ALBERT

Description: 〈p〉Publication date: 31 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 408〈/p〉 〈p〉Author(s): Guoping Chen, Xiong Song, Suqing Wang, Xinzhi Chen, Haihui Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lithium-sulfur (Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉S) batteries are attractive candidates for advanced energy storage devices. However, the low utilization of sulfur and the severe “shuttle effect” hinder the commercialization of Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉S batteries. Herein, we design an ultra-thin and lightweight two-dimensional (2D) molybdenum nitride nanosheets layer to modify Celgard (denoted as MoN〈sub〉x〈/sub〉/Celgard) separator to promote the electrochemical performance of Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉S batteries. Benefiting from the 2D polar molybdenum nitride nanosheets, the obtained molybdenum nitride layer can effectively suppress the shuttle effect via the synergistic effect of structural confinement and chemical absorption. Meanwhile, molybdenum nitride nanosheets layer possesses metallic and catalytic characteristics, which are beneficial for high sulfur utilization. Therefore, the Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉S batteries using MoN〈sub〉x〈/sub〉/Celgard separator with multifunction exhibit high capacity and outstanding cycling performance. It delivers a high discharge capacity of 1298 mA h g〈sup〉−1〈/sup〉 at 0.1C and sustain a capacity of 566 mA h g〈sup〉−1〈/sup〉 after 500 cycles at 0.5C, corresponding with the capacity fading rate of only 0.063% per cycle.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 31 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 408〈/p〉 〈p〉Author(s): Yilan Wu, Xin Fan, Rohit Ranaganathan Gaddam, Qinglan Zhao, Dongfang Yang, Xiaoming Sun, Chao Wang, X.S. Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sodium-ion capacitors with unique characteristics such as higher energy density than electrical double-layer capacitors, higher power density than rechargeable batteries, and abundant sodium resources represent current research trend in developing large-scale electrical energy storage technology. One of the key challenges presently facing the development of this technology is the imbalanced kinetics between the sluggish Faradaic sodium insertion in the anode and the fast capacitive ion adsorption on the cathode. Here we demonstrate the sol-gel synthesis of a novel, high-rate, stable composite anode material for sodium-ion capacitors (NICs). The composite consisted of Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanoparticles embedded in a carbon matrix (denoted by m-Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉/C). Sodium-ion capacitors employing the m-Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉/C anode and a commercial activated carbon as the cathode showed an admirable performance, delivering high energy densities in a wide range of power densities (73 Wh kg〈sup〉−1〈/sup〉@250 W kg-1 and 16.8 Wh kg〈sup〉−1〈/sup〉@20 kW kg〈sup〉−1〈/sup〉). These favourable cell characteristics are attributed to the properties of the m-Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉/C anode: the mesoporous structure that facilitates electron and ion transport, the presence of the niobium carbide interlayer between the Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanoparticles and the surrounding graphitic carbon that additionally improves the electron conductivity, and the predominant capacitive charge storage mechanism.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311881-fx1.jpg" width="302" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 31 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 408〈/p〉 〈p〉Author(s): Yuyan Zhang, Pei Tian, Kexun Li, Yi Liu, Zhaohui Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A highly active electrocatalyst is synthesized by employing melamine assisted metal-organic framework as the precursor. By pyrolyzing the hybrid at 350–800 °C, the precursor can be easily transferred into abundant iron and nitrogen co-doped carbon skeleton. The microbial fuel cell doped with the above treated sample at 600 °C achieves the maximum power density 2229 ± 10 mW m〈sup〉−2〈/sup〉, 257% and 36.6% higher than that of activated carbon and the control sample. The total resistance decreases by 53.8% from 18.16 Ω (activated carbon) to 8.39 Ω. The reaction process is testified to be four-electron transfer. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy prove the coexistence of divalent copper and C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and the incorporation of nitrogen into the network formed active sites. Thus, the ideal results make the pyrolyzed hybrid at 600 °C a promising catalyst in microbial fuel cell.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 31 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 408〈/p〉 〈p〉Author(s): Guiping Ren, Yuan Sun, Anhuai Lu, Yan Li, Hongrui Ding〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Anode electron transfer efficiency is one of the main bottlenecks in determining the performance of microbial fuel cells (MFCs). Here, we report for the first time a novel design of a silicon solar cell equipped MFC with one-dimensional TiO〈sub〉2〈/sub〉/Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 photoanode and conventional bioanode to overcome the constraints of using traditional anodes. The novel MFC has the maximum power density of 638.3 mW m〈sup〉−2〈/sup〉, which is nearly 7.6 times higher than that of general MFCs (84.2 mW m〈sup〉−2〈/sup〉). In addition, the novel MFC achieves 90.9% removal of hexavalent chromium Cr(VI) with concentration of 50 ppm within 13.5 h, and this rate is significantly high at 3.67 g m〈sup〉−3〈/sup〉 h〈sup〉−1〈/sup〉. Efficient microbial oxidation and photoelectrocatalysis are realized after constructing the SSC with double-anode MFC, thereafter leading to enhanced electron transfer to the external circuit. In addition, the electrons are driven by the built-in electric field in silicon solar cell, in which system barriers are resolved at the same time. Power output and Cr(VI) reduction efficiency are both remarkably enhanced. Such a novel MFC strategy provides new directions for designing new systems that can increase the efficiency of MFCs by utilizing solar energy economically, which further suggest great potential in environmental remediation.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311893-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 31 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 408〈/p〉 〈p〉Author(s): Xiumei Guo, Nana Bai, Yan Tian, Ligang Gai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Flexible all-solid-state supercapacitors with specific energy higher than 1 mW h cm〈sup〉−3〈/sup〉 after long-term cycles remain a hot research topic in energy storage systems. In this paper, free-standing reduced graphene oxide/polypyrrole films are produced at the ice/ethanol interface following by hydrogen iodide reduction. The reduced graphene oxide/polypyrrole films are featured with high specific surface area, three-dimensional porosity, and tunable thickness and electronic conductivity. The typical flexible all-solid-state supercapacitor based on reduced graphene oxide/polypyrrole films exhibits a high volumetric specific capacitance of 17.3 F cm〈sup〉−3〈/sup〉 and a high specific energy of 2.40 mW h cm〈sup〉−3〈/sup〉 with corresponding specific power of 136.1 mW cm〈sup〉−3〈/sup〉 at a current density of 3 mA cm〈sup〉−2〈/sup〉 (ca. 10 A g〈sup〉−1〈/sup〉). After 10,000 cycles at 3 mA cm〈sup〉−2〈/sup〉, the capacitance retention of the typical flexible supercapacitor retains 73.2%. The enhanced electrochemical properties of the flexible supercapacitors are attributed to the high specific surface area, three-dimensional porosity, and the synergistic effect between reduced graphene oxide and polypyrrole with respect to the composite films.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311911-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 31 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 408〈/p〉 〈p〉Author(s): Muhammad Rauf, Jing-Wen Wang, Peixin Zhang, Waheed Iqbal, Junle Qu, Yongliang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The exploration of cheap and stable electrocatalysts with high activity towards oxygen reduction reaction in the acidic and alkaline medium is a vital activity for large-scale applications of fuel cells. In recent years, one-dimensional nanofibrous electrode materials with high surface area and specific porosities have been drawing great attention in energy conversion devices such as fuel cells and metal-air batteries. Nanofibers with a one-dimensional nanostructure can be produced by electrospinning, which has been considered as a particularly low-cost and versatile method. In this review, we summarize the properties of electrospun nanofibers and the recent progress in designing of non-precious nanostructured electrocatalysts for oxygen reduction reaction in fuel cells. More importantly, we also highlight the interesting nanostructures, new synthetic approaches, and the electrocatalytic performance including active sites and stability of electrospun-based electrocatalysts. In addition, we describe the research challenges and future developmental perspectives of electrospun materials in energy technology.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 31 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 408〈/p〉 〈p〉Author(s): Yijie Xu, Dustin Bauer, Mechthild Lübke, Thomas E. Ashton, Yun Zong, Jawwad A. Darr〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sodium titanate nanopowder (nominal formula Na〈sub〉1.5〈/sub〉H〈sub〉0.5〈/sub〉Ti〈sub〉3〈/sub〉O〈sub〉7〈/sub〉) was directly synthesized using a continuous hydrothermal flow synthesis process using a relatively low base concentration (4 M NaOH) in process. The as-made titanate nanomaterials were characterised using powder X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, Brunauer–Emmett–Teller analysis and transmission electron microscopy, and evaluated as potential electrode materials for Li-ion and Na-ion batteries. Cyclic voltammetry studies on half-cells revealed that the sodium titanate nanomaterial stored charge primarily through a combination of pseudocapacitive and diffusion-limited processes in both systems. Electrochemical cycling tests at a high specific current of 1000 mA g〈sup〉−1〈/sup〉, revealed that the Li-ion and Na-ion cells retained relatively high specific capacities after 400 cycles of 131 and 87 mAh g〈sup〉−1〈/sup〉, respectively. This study demonstrates the potential of CHFS-made sodium titanate nanopower as an anode material for both Li- and Na-ion cell chemistries.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311406-fx1.jpg" width="428" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 31 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 408〈/p〉 〈p〉Author(s): Yannick Garsany, Robert W. Atkinson, Benjamin D. Gould, Karen E. Swider-Lyons〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present a method for preparing laboratory-scale proton exchange membrane fuel cells (PEMFCs) that have high power and high current densities despite their low platinum loadings. This performance is achieved with membrane electrode assemblies featuring a commercial PtCo catalyst supported on high surface area carbon and a short-side chain, low equivalent weight ionomer binder in the cathode catalyst layer; these are then compressed with dry-laid paper type gas diffusion media. The PEMFCs with a Pt loading of 0.08 mg〈sub〉Pt〈/sub〉 cm〈sup〉−2〈/sup〉 produced comparatively high power to similarly loaded state-of-the-art PEMFCs. This methodology can be used for further research on high performance catalyst layers.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311819-fx1.jpg" width="341" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 409〈/p〉 〈p〉Author(s): Xianlin Xu, Guodong Zhao, Hang Wang, Xiaojie Li, Xi Feng, Bowen Cheng, Lei Shi, Weimin Kang, Xupin Zhuang, Yan Yin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Proton exchange membranes with remarkable performance are important for the development of direct methanol fuel cells. Inspired by the proton-conducting mechanism of transmembrane proteins, amino-acid-functionalized cellulose whiskers, are developed as a novel proton-conducting pathway for hybrid proton exchange membranes. Fmoc-amino acids are immobilized onto the surface of cellulose whiskers to obtain amino acids (Glycine, 5-amino-Valeric acid, 〈span〉l〈/span〉-Serine, 〈span〉l〈/span〉-Asparagine, and 〈span〉l〈/span〉-Leucine) functionalized cellulose whiskers with primary amino groups after Fmoc-deprotection. Proton-conducting mixed-matrix membranes are obtained by incorporating amino-acid-functionalized cellulose whiskers into sulfonated polysulfone. The performance of hybrid proton exchange membranes is evaluated to study the effects of the structure and content of amino acids. Results shows that the introduction of amino acids considerably enhances the proton conductivity. Proton exchange membranes with 4 wt.% and 10 wt.% content of 〈span〉l〈/span〉-Serine-functionalized cellulose whiskers have high proton conductivity of 0.209 S/cm and 0.234 S/cm at 80 °C, respectively. In addition, water uptake, resistance to methanol permeability and single-cell performance are also enhanced. These results indicates that the composition of filler and mixed matrix exhibit remarkable properties, and proton-conducting mixed-matrix membranes are promising materials in direct methanol fuel cells.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Hiroki Sakai, Yukinori Taniguchi, Kohei Uosaki, Takuya Masuda〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanoscale Young's modulus mapping of the cross-section of electrode composite films used in lithium ion batteries was carried out using bimodal atomic force microscopy. Clear difference in Young's modulus was observed between the particles of active materials and matrix of conductive additives/binders in the composites of LiCoO〈sub〉2〈/sub〉-based positive and graphite-based negative electrodes. Interestingly, there were a few particles showing significantly reduced Young's modulus in the 100% state-of-charge positive electrode although such particles were not present in the pristine electrode.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313545-fx1.jpg" width="320" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Pravin N. Didwal, Rakesh Verma, Chan-Woo Min, Chan-Jin Park〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Three-dimensional (3-D) interconnected porous Na〈sub〉3〈/sub〉V〈sub〉2〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉 coated with carbon (NVP@C) is synthesised by a simple modified sol-gel method. When 15 wt% glucose is used as the carbon precursor, the obtained NVP@C15 composite exhibits excellent electrochemical performance as a cathode as well as an anode for sodium-ion batteries (SIBs). As a cathode, the NVP@C15 electrode delivers a high capacity of 116.9 mAh g〈sup〉−1〈/sup〉 at a rate of 1 C, which is close to its theoretical capacity. Even at a high rate of 20C, the NVP@C15 electrode exhibits an initial reversible capacity of 99.2 mAh g〈sup〉−1〈/sup〉 and a capacity retention of 77% after 6000 cycles. As an anode, the NVP@C15 delivers an initial reversible capacity of 85.8 mAh g〈sup〉−1〈/sup〉 at a rate of 1C. At higher rates of 10 and 20C, a remarkably good cyclability, with a capacity retention of 76% over 4000 cycles and 62% over 5000 cycles, respectively, is achieved. Furthermore, the full cell, composed of two symmetric NVP@C15 electrodes, exhibits an initial reversible capacity of 73 mAh g〈sup〉−1〈/sup〉 at a rate of 1C. In addition, capacity retentions of 88% after 100 cycles and 61% after 500 cycles are obtained at rates of 1C and 5C, respectively.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313697-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Muhammad Yousif, Qian Ai, Waqas Ahmad Wattoo, Ziqing Jiang, Ran Hao, Yang Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A number of valid possible arrangements of renewable energy sources (wind turbines, solar photovoltaics) with energy storage systems (electrochemical storage, fuel cell, battery) for the large-scale electric grid system (26 GW) are explored in this paper. There are two core motivations for choosing such arrangements. First, the same type of renewable resources located at a single site have high fluctuation, so we model various type of renewable resources located at various locations to have lesser fluctuations accompanied with relatively compact energy storage systems. The second incentive is to find the true minimum cost combination, excluding subsidies and relaxation in taxes for governments. This study includes the whole year (hourly, 8760 h in total) electric load and related weather elements. It is found that the least cost combinations require excessive generation capacity, diverse renewable generation resources and energy storage techniques, which would meet the load requirements and have less carbon emissions.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313399-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Haoqing Lin, Peng liu, Shaofeng Wang, Zhenbao Zhang, Ziyang Dai, Shaozao Tan, Dengjie Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Perovskite LaMnO〈sub〉3〈/sub〉 is reported to be a superior electrocatalyst for oxygen reduction reaction in terms of the onset potential and intrinsic activity. However, traditionally prepared LaMnO〈sub〉3〈/sub〉 is characterized to exhibit a low specific surface area and a limited pore volume. Herein, we synthesize a three-dimensional ordered macroporous LaMnO〈sub〉3〈/sub〉 that features ordered and interconnected porous structure, in order to increase catalytic sites. The obtained three-dimensional ordered macroporous LaMnO〈sub〉3〈/sub〉 exhibits an increased specific surface area of 20.328 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉 and pore volume of 0.126 cm〈sup〉3〈/sup〉 g〈sup〉−1〈/sup〉. Rotating-ring-disk electrode measurement reveals a more positive onset potential (0.827 V) and half-wave potential (0.686 V), and a much higher current-limited density (5.90 mA cm〈sup〉−2〈/sup〉) of the three-dimensional ordered macroporous LaMnO〈sub〉3〈/sub〉 compared to counterparts, as well as a high electron transfer number (∼4) and a better stability. Furthermore, a Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈sub〉2〈/sub〉 battery employing the three-dimensional ordered macroporous LaMnO〈sub〉3〈/sub〉 as air electrode exhibits excellent electrochemical performance with a higher initial discharge capacity (5592 mAh g〈sup〉−1〈/sup〉), a smaller discharge-charge voltage gap (1.56 V), and a higher coulombic efficiency (∼100%) in comparison with the carbon electrode. Our results suggest that traditional perovskite oxides could be effectively optimized for efficient electrocatalytic reactions.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313569-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Heng Shao, Diankai Qiu, Linfa Peng, Peiyun Yi, Xinmin Lai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is necessary to obtain internal heat and water distribution of proton exchange membrane fuel cells in order to perform water-heat management. Most of the existing works focus on the measurement in small experimental fuel cells, which cannot effectively guide the development of large-area fuel cells. In this study, an in-situ measurement method using micro-sensors is developed to observe the temperature and relative humidity in a commercial-size fuel cell with parallel flow fields and an active area of 250 cm〈sup〉2〈/sup〉. A sensor array is incorporated into the cathode flow field, and well-designed waterproof and sealing structures protect sensors from liquid water. The sensors are verified with accuracy and response speed. The fuel cell performance and electrochemical impedance spectroscopy under co-flow and counter-flow configurations considering anode gas humidification are investigated. The results show that the temperature distribution is more uneven in the cases with lower output voltage, and the fuel cell performance is significantly affected by the humidity near the air inlet area. As current density increases, the relative humidity drops while dew point temperature keeps almost unchanged. The experimental method and analysis are beneficial to the understanding of the water-heat state and optimization of fuel cell stack design.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Derun Li, Wenfeng Guo, Yanshuai Li, Yongfu Tang, Jitong Yan, Xiaojuan Meng, Meirong Xia, Faming Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To increase the storage capacity and improve the sluggish ion diffusion in the titanium oxide negative electrode for aqueous asymmetric supercapacitors, a novel binder-free titanium supported K〈sup〉+〈/sup〉 intercalated hollandite TiO〈sub〉2〈/sub〉 electrode with large (2 × 2) atom tunnels is facilely synthesized via a phase transformation from anatase TiO〈sub〉2〈/sub〉 to hollandite TiO〈sub〉2〈/sub〉 in a high temperature (220 °C) alkaline hydrothermal system combining with a post ion exchange process to partially extract the intercalated K〈sup〉+〈/sup〉 ions. The as-prepared K〈sup〉+〈/sup〉 intercalated hollandite TiO〈sub〉2〈/sub〉 electrode delivers a high areal capacitance of 526.6 mF cm〈sup〉−2〈/sup〉 due to that the (2 × 2) atom tunnels provide large space for the Li〈sup〉+〈/sup〉 ion storage and suitable pathway for ionic transport. A novel 2.4 V flexible all-solid-state asymmetric supercapacitor, assembled with the as-prepared hollandite TiO〈sub〉2〈/sub〉 negative electrode, carbon cloth supported MnO〈sub〉2〈/sub〉 positive electrode and LiCl/polyvinyl alcohol gel electrolyte, exhibits high voltage window of 2.4 V, high volumetric energy density of 63.9 mWh cm〈sup〉−3〈/sup〉, good cycle-performance and excellent flexibility, suggesting its promising practical applications in energy storage. The studies offer a novel strategy to enhance the capacitance and rate-performance of the TiO〈sub〉2〈/sub〉 based negative electrode for the flexible high voltage aqueous or all-solid-state asymmetric supercapacitors.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313430-fx1.jpg" width="287" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Hongmei Ji, Chao Ma, Jingjing Ding, Jie Yang, Gang Yang, Yimin Chao, Yang Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To limit the pulverization of tin-based anode materials during lithiation/delithiation, submicron tin oxide/tin particles are fixed on core/sheath carbon nanofiber/spongy carbon via hydrothermal and carbothermal reduction treatment in this work. During carbothermal reduction, SnO〈sub〉2〈/sub〉 nanosheets are converted to spherical Sn submicron particles and simultaneously the hollow spongy carbon is produced and still enwrap on carbon nanofiber. The as-produced flexible film is used for a binder-free anode for lithium ion batteries, without the polymer binder and conductive carbon. At 0.1, 0.5, 1 and 2 A g〈sup〉−1〈/sup〉, the composite electrode respectively displays a discharging capacity of 1393.0, 738.2, 583.6 and 382.6 mAh g〈sup〉−1〈/sup〉. Moreover, it delivers specific capacity of 726.9 mAh g〈sup〉−1〈/sup〉 and coulombic efficiency of 99.45% after 300 cycles at 0.1 A g〈sup〉−1〈/sup〉. The comparison sample of carbon nanofiber/SnO〈sub〉〈em〉x〈/em〉〈/sub〉 film without the presence of spongy carbon displays much lower rate performance and worse cyclic performance. The integrated structure of carbon nanofiber/SnO〈sub〉〈em〉x〈/em〉〈/sub〉/spongy carbon results in the remarkable Li-storage performance, in which the carbon nanofiber and spongy carbon synergistically provide conductive channel and buffer zone to hinder the pulverization and peeling of SnO〈sub〉〈em〉x〈/em〉〈/sub〉 particles during charging-discharging processes.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313739-fx1.jpg" width="476" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Y. Wu, J.I.S. Cho, X. Lu, L. Rasha, T.P. Neville, J. Millichamp, R. Ziesche, N. Kardjilov, H. Markötter, P. Shearing, D.J.L. Brett〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In-depth understanding of the effect of compression on the water management in polymer electrolyte fuel cells (PEFCs) is indispensable for optimisation of performance and durability. Here, in-operando neutron radiography is utilised to evaluate the liquid water distribution and transport within a PEFC under different levels of compression. A quantitative analysis is presented with the influence of compression on the water droplet number and median droplet surface area across the entire electrode area. Water management and performance of PEFCs is strongly affected by the compression: the cell compressed at 1.0 MPa demonstrates ∼3.2% and ∼7.8% increase in the maximum power density over 1.8 MPa and 2.3 MPa, respectively. Correlation of performance to neutron radiography reveals that the performance deviation in the mass transport region is likely due to flooding issues. This could be ascribed to the loss of the porosity and increased tortuosity factor of the gas diffusion layer under the land at higher compression pressure. The size and number of droplets formed as a function of cell compression was examined: with higher compression pressure, water droplet number and median droplet surface area rapidly increase, showing the ineffective water removal, which leads to fuel starvation and the consequent performance decay.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 4 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources〈/p〉 〈p〉Author(s): Xing Zhou, Zhengqiang Pan, Xuebing Han, Languang Lu, Minggao Ouyang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The need for a quick yet informative technique for diagnosing the lithium-ion batteries is escalating. Conventional impedance-based diagnosis methods are usually time-demanding for a complete electrochemical impedance spectroscopy measurement and involve complicated calculations to extract battery information, which therefore have limited applications in battery monitoring. In this study, we propose a multi-point impedance technique, involving impedance measurement on three characteristic frequency points and being able to separate ohmic, contact and solid electrolyte interphase resistances. The characteristic frequency points are calibrated using distribution of relaxation time method. This multi-point impedance technique holds potential for large-scale high-throughput battery monitoring and screening.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313429-fx1.jpg" width="312" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): R.A. Escalona-Villalpando, E. Ortiz-Ortega, J.P. Bocanegra-Ugalde, Shelley D. Minteer, J. Ledesma-García, L.G. Arriaga〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of devices capable of generating energy through biofluids, such as sweat, is an effort to integrate flexible devices that can be powered and used on the skin. A patch-type completely enzymatic biofuel cell (p-EBFC) is developed using bilirubin oxidase- and lactate oxidase-based electrodes as biocathode and bioanode respectively, where both enzymes are immobilized on flexible Toray carbon paper-modified. The evaluation of the half-cells shows that the bioelectrodes had good catalytic activity towards the oxygen reduction and lactic acid oxidation reactions using natural human sweat. The wireless p-EBFC on the skin is capable to delivery an open circuit voltage of 0.55 ± 0.03 V and a short circuit current of 140 ± 4 μA cm〈sup〉−2〈/sup〉. Also, the p-EBFC maintains its performance of 20 μW cm〈sup〉−2〈/sup〉 and 30 μA cm〈sup〉−2〈/sup〉 continuously for 30 min in a sweat delivery from the arm of a healthy volunteer during workouts. In addition, a wireless device is incorporated in order to monitor via a cell phone the energy produced in real time.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Xuyang Zhang, Xu Zhang, Hidetaka Taira, Hongtan Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A serpentine flow field is commonly used in both fuel cells and redox flow batteries. Accurate prediction of mass transfer in the porous gas/liquid diffusion layer (GDL/LDL) is essential for both flow field design optimization and pressure drop predictions. Darcy's law has been widely used to predict fluid flow through GDL/LDL in fuel cells and flow batteries. However, since the inertial effect is neglected in the Darcy's law, significant errors can arise when it is applied to serpentine flow fields. In this work, dimensional analyses are performed using both the Buckingham Pi-theorem and the analytical models developed earlier based on Darcy's law and modified Darcy's law. From the Pi-theorem, four and five non-dimensional parameters are obtained from the Darcy's law and the modified Darcy's law, respectively. The variations of Darcy's law errors in predicting under-land cross-flow rate with each of the non-dimensional parameters are studied. By comparing the coefficient of each term of the two models, two independent Pi-terms for under-land cross-flow rate are obtained. The criterion for applicability of Darcy's law is developed based on the two Pi-terms. The model predicted errors of Darcy's law compared very well with experimental data, thus further confirms the applicability of developed criterion.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): William Manalastas, Jokin Rikarte, Richard J. Chater, Rowena Brugge, Ainara Aguadero, Lucienne Buannic, Anna Llordés, Frederic Aguesse, John Kilner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metallic Li anodes are key to reaching high energy densities in next-generation solid-state batteries, however, major problems are the non-uniform deposition of Li at the interface and the penetrative power of Li metal during operation, which cause failure of the ceramic electrolyte, internal short-circuits and a premature end of battery life. In this work, we explore the anode-electrolyte interface instability of a Li metal-garnet electrolyte system during Li electrodeposition, and its implications for mechanical fracture, Li metal propagation, and electrolyte failure. The degradation mechanism was followed step-by-step during in-operando electrochemical cycling using optical and scanning electron microscopy. High amounts of Li electrodeposition in a localized zone of the interface lead to ceramic fracture followed by an electrode-to-electrode electrical connection via a conductor Li metal filament. This work enables deeper understanding of battery failure modes in all-solid-state batteries containing a ceramic electrolyte membrane.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318312825-fx1.jpg" width="278" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Jun Zhang, Chao Zheng, Jiatao Lou, Yang Xia, Chu Liang, Hui Huang, Yongping Gan, Xinyong Tao, Wenkui Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Argyrodite Li〈sub〉6〈/sub〉PS〈sub〉5〈/sub〉Cl is a promising solid electrolyte in all-solid-state lithium batteries owing to its high ionic conductivity. However, the poor mechanical property and undesirable interfacial property restrict its application. In order to solve these issues, we fabricate Li〈sub〉6〈/sub〉PS〈sub〉5〈/sub〉Cl/poly(ethylene oxide) composite solid electrolytes with enhanced mechanical property and stable lithium/electrolyte interface. By adding 5 to 20 wt% poly(ethylene oxide), the proportional limit of composite solid electrolytes is enhanced by ∼150%, reaching a value up to 60 MPa. With 5 wt% poly(ethylene oxide), the as-assembled sandwich-type LiNi〈sub〉0〈/sub〉〈sub〉·〈/sub〉〈sub〉8〈/sub〉Co〈sub〉0〈/sub〉〈sub〉·〈/sub〉〈sub〉1〈/sub〉Mn〈sub〉0〈/sub〉〈sub〉·〈/sub〉〈sub〉1〈/sub〉O〈sub〉2〈/sub〉/composite solid electrolytes/Li battery exhibits enhanced cycling performance with a capacity retention rate of 91% over 200 cycles at 0.05C and 30 °C. 〈em〉Ex situ〈/em〉 characterizations reveal that by adding suitable poly(ethylene oxide) content in Li〈sub〉6〈/sub〉PS〈sub〉5〈/sub〉Cl, the interfacial reactions and lithium dendrite growth can be effectively inhibited, resulting in much improved cycling performance of all-solid-state lithium batteries.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318312771-fx1.jpg" width="275" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Weijian Tang, Zhangxian Chen, Fan Xiong, Fei Chen, Cheng Huang, Qiang Gao, Tongzhen Wang, Zeheng Yang, Weixin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nowadays nickel-rich LiNi〈sub〉x〈/sub〉Co〈sub〉y〈/sub〉Mn〈sub〉1-x-y〈/sub〉O〈sub〉2〈/sub〉 (0.5 〈 x 〈 1) cathode materials attract great research interests due to their high specific capacity in lithium ion batteries. However, poor cycling performance and serious safety concerns trade off their benefits. Here, we present an effective etching-induced coating strategy for surface modification of LiNi〈sub〉0.8〈/sub〉Co〈sub〉0.1〈/sub〉Mn〈sub〉0.1〈/sub〉O〈sub〉2〈/sub〉 cathode materials by LiAlO〈sub〉2〈/sub〉. Hydrolysis of AlCl〈sub〉3〈/sub〉 creates H〈sup〉+〈/sup〉 to etch the hydroxide precursor of LiNi〈sub〉0.8〈/sub〉Co〈sub〉0.1〈/sub〉Mn〈sub〉0.1〈/sub〉O〈sub〉2〈/sub〉 and to induce oriented deposition of Al(OH)〈sub〉3〈/sub〉 layer on surface of the hydroxide precursor, which is transformed into uniform γ-LiAlO〈sub〉2〈/sub〉 coating on the LiNi〈sub〉0.8〈/sub〉Co〈sub〉0.1〈/sub〉Mn〈sub〉0.1〈/sub〉O〈sub〉2〈/sub〉 particles after the subsequent lithium impregnating and annealing. The 2.2 wt% LiAlO〈sub〉2〈/sub〉-coated LiNi〈sub〉0.8〈/sub〉Co〈sub〉0.1〈/sub〉Mn〈sub〉0.1〈/sub〉O〈sub〉2〈/sub〉 cathode delivers a high rate capacity of 135.2 mAh g〈sup〉−1〈/sup〉 at 10 C and long cyclability with capacity retention of 85.8% after 200 cycles at 0.5 C. In addition, the thermal stability of LiAlO〈sub〉2〈/sub〉-coated LiNi〈sub〉0.8〈/sub〉Co〈sub〉0.1〈/sub〉Mn〈sub〉0.1〈/sub〉O〈sub〉2〈/sub〉 is significantly improved. The enhanced battery performances are due to partial Al〈sup〉3+〈/sup〉 doping and Li〈sup〉+〈/sup〉 conductive LiAlO〈sub〉2〈/sub〉 coating layer that provides well-connected networks for Li〈sup〉+〈/sup〉 transport, improves the structural stability and prevents core materials from the attack by side products.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The detailed etching-induced coating strategy for the synthesis of LiAlO〈sub〉2〈/sub〉-coated NCM811 materials.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313090-fx1.jpg" width="258" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Heng Wang, Chuang Yu, Swapna Ganapathy, Ernst R.H. van Eck, Lambert van Eijck, Marnix Wagemaker〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The increased safety associated with all-solid-state batteries using inorganic ceramic electrolytes make it a promising technology, with potential to replace current commercial battery systems. The key challenges to realize this technology are the development of new solid electrolytes with high ionic conductivity and optimization of the ionic transport pathways across the multiple phases of the battery. In this study an optimal composition of the argyrodite 〈em〉i.e.〈/em〉 Li〈sub〉6〈/sub〉PS〈sub〉5〈/sub〉Cl〈sub〉0.5〈/sub〉Br〈sub〉0.5〈/sub〉 is synthesized via the mechanical milling method. This material possesses a higher bulk ionic conductivity and reduced activation energy than the single halogen doped argyrodites 〈em〉i.e.〈/em〉 Li〈sub〉6〈/sub〉PS〈sub〉5〈/sub〉X (X = Cl and Br), assessed by temperature-dependent impedance spectroscopy and Nuclear Magnetic Resonance (NMR) relaxometry. A combined X-ray and neutron diffraction analysis reveals an influence of the composition and distribution of halogen atoms on the Li-ion conductivity. All-solid-state batteries fabricated using Li〈sub〉2〈/sub〉S as cathode show a high reversible capacity of 820 mAh g〈sup〉−1〈/sup〉 for up to 30 cycles. In addition, the Li-ion diffusion across the interface between the Li〈sub〉2〈/sub〉S cathode and Li〈sub〉6〈/sub〉PS〈sub〉5〈/sub〉Cl〈sub〉0.5〈/sub〉Br〈sub〉0.5〈/sub〉 electrolyte is probed by exchange NMR spectroscopy. It reveals that Li-ion diffusion across this interface was the main factor limiting the performance of Li〈sub〉6〈/sub〉PS〈sub〉5〈/sub〉Cl〈sub〉0.5〈/sub〉Br〈sub〉0.5〈/sub〉 in the battery, despite its high bulk ionic conductivity.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318312643-fx1.jpg" width="422" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Qi Li, Shuangxi Sun, Anderson D. Smith, Per Lundgren, Yifeng Fu, Peng Su, Tao Xu, Lilei Ye, Litao Sun, Johan Liu, Peter Enoksson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the establishment of the internet of things (IoT) and the rapid development of advanced microsystems, there is a growing demand to develop electrochemical capacitors (ECs) to replace bulky electrolytic capacitors on circuit boards for AC line filtering, and as a storage unit in energy autonomous systems. For this purpose, ECs must be capable of handling sufficiently high signal frequencies, display minimum energy loss through self-discharge and leakage current as well as maintaining an adequate capacitance. Here, we demonstrate ECs based on mechanically flexible, covalently bonded graphite/vertically aligned carbon nanotubes (graphite/VACNTs) hybrid materials. The ECs employing a KOH electrolyte exhibit a phase angle of −84.8°, an areal capacitance of 1.38 mF cm〈sup〉−2〈/sup〉 and a volumetric capacitance (device level) of 345 mF cm〈sup〉−3〈/sup〉 at 120 Hz, which is among the highest values for carbon based high frequency ECs. Additionally, the performance as a storage EC for miniaturized systems is evaluated. We demonstrate capacitive charging/discharging at μA current with a gel electrolyte, and sub-μA leakage current reached within 50 s, and 100 nA level equilibrium leakage within 100 s at 2.0 V floating with an ionic liquid electrolyte.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318312990-fx1.jpg" width="496" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Serkan Sevinc, Burak Tekin, Ali Ata, Mathieu Morcrette, Hubert Perrot, Ozlem Sel, Rezan Demir-Cakan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In-situ formation of pure olivine NaFePO〈sub〉4〈/sub〉 from chemically synthesized LiFePO〈sub〉4〈/sub〉 nanoparticles via an electrochemical ion-exchange route in sodium salt containing aqueous electrolyte is reported. Both in-situ electrochemical quartz crystal microbalance (EQCM) and in-situ X-ray diffraction (XRD) measurements are performed to monitor the formation of NaFePO〈sub〉4〈/sub〉. Subsequently, a rechargeable Na-ion aqueous polysulfide battery is demonstrated where NaFePO〈sub〉4〈/sub〉 and dissolved Na〈sub〉2〈/sub〉S〈sub〉5〈/sub〉 solution are used as cathode and anolyte, respectively; and are separated from each other by an ion-exchange polymeric membrane. In order to prevent diffusion of Na〈sub〉2〈/sub〉S〈sub〉5〈/sub〉 polysulfide from the anode to the cathode side, salt concentration at both sides of the NaFePO〈sub〉4〈/sub〉||Na〈sub〉2〈/sub〉S〈sub〉5〈/sub〉 full cell is finely tuned resulting a 45 mAh g〈sup〉−1〈/sup〉 cycling capacity over 200 cycles.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S037877531831276X-fx1.jpg" width="304" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Nan Cai, Jialu Wu, Rulin Dong, Changchun Jin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electrochemical deposition of small amounts of Au and Pt on the surface of Ni nanoparticles supported on reduced graphene oxide and the electrooxidation of ethylene glycol on the AuPt-decorated Ni/reduced graphene oxide catalysts in alkaline solution are investigated. By selecting a short deposition time, a low concentration of metal precursors, and a positive applied potential, AuPt loadings of less than 1.0 μg cm〈sup〉−2〈/sup〉 are obtained. Physical and electrochemical characterizations of AuPt/Ni/reduced graphene oxide reveal a much lower content of Pt relative to Au. However, AuPt/Ni/reduced graphene oxide behaves similar to monometallic Pt/reduced graphene oxide rather than to Au/reduced graphene oxide in ethylene glycol oxidation, while Ni/reduced graphene oxide and Pt-decorated Ni/reduced graphene oxide show no activity. Compared to Pt/reduced graphene oxide or Au/reduced graphene oxide, the peak intensities of AuPt/Ni/reduced graphene oxide are somewhat higher in terms of the glassy carbon substrate, but are significantly higher in terms of the AuPt mass loading. Another attractive feature of AuPt/Ni/reduced graphene oxide is low cost resulted from the low AuPt loading. The result of this study indicates that decorating the surface of non-noble metal with a small amount of two noble metals is an efficient method to fabricate highly active catalysts.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Yuchuan Liu, Baobing Huang, Xuefei Zhang, Xing Huang, Zailai Xie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Iron and nitrogen co-doped carbons show great potential for high-performance electrochemical oxygen reduction reaction. However, the rational design of atomically dispersed iron over nitrogen-doped carbons with activity comparable to that of Pt-C is still challenging. Herein, we develop a new approach that enables the direct formation of intrinsically nitrogen-functionalized two-dimensional sheet-like carbons containing a high concentration of single Fe atoms. This strategy only involves one-step pyrolysis of both, guanine and iron nitrate, without using any guiding agent and sacrificial template. The electrochemistry tests demonstrate an excellent ORR performance of the prepared Fe-N〈sub〉x〈/sub〉-C catalyst with a half-wave potential of 0.85 V and a limited current density of −6.5 mA/cm〈sup〉2〈/sup〉 in alkaline medium, outperforming the commercial Pt-C and most of previously reported Fe-N〈sub〉x〈/sub〉-C catalysts. We believe that the emergence of superior ORR performance is mostly attributed to the uniform dispersion of single Fe atoms at the molecular level and the formation of abundant coordinated Fe-N〈sub〉x〈/sub〉 sites. In addition, the high surface area, optimal porosity and defective structure (particularly the defects at the edge) of the two-dimensional carbons are also beneficial for the improved ORR activity.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S037877531831259X-fx1.jpg" width="475" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): A. Sorrentino, T. Vidakovic-Koch, K. Sundmacher〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present contribution an experimental validation and a measurement routine of a new electrochemical method to study dynamics of electrochemical processes, the so-called concentration alternating frequency response analysis (cFRA) is presented. In cFRA the electrical response of the cell (current or potential) to periodic perturbation of specific reactant feeds is studied by means of linear system analysis. For the example of a polymer electrolyte fuel cell (PEMFC) we show that cFRA, in contrast to classical electrochemical impedance spectroscopy (EIS), detects selectively the effect of the dynamics of mass transport of reactants and products inside the different layers of the PEMFC. Moreover, cFRA can be used to diagnose the humidification state of the fuel cell cathode. Finally, procedures to improve the diagnostic skills of the proposed cFRA technique are discussed and directions of future work are recommended.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313120-fx1.jpg" width="284" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Jing Xiong, Shaoliang Wang, Xiangrong Li, Zhigang Yang, Jianguo Zhang, Chuanwei Yan, Ao Tang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Stack reliability is of great importance in commercialization of vanadium redox flow battery (VFB) since practical VFB stacks are prone to undergo material failure and electrolyte leakage caused by unreliable stack design and improper assembling conditions. A comprehensive evaluation of mechanical behavior and analysis of stack failure is thus highly valued for material fabrication, stack design and assembly. In this study, mechanical behavior and Weibull statistics based failure analysis of the VFB stacks are investigated. The Weibull parameters of two key components are firstly determined from tensile strength tests, which, in combination with finite element analysis of the stack mechanical behavior, are subsequently used to calculate the stack failure probability at specified clamping forces for two different stack designs that both contains 20 individual cells. The results demonstrate that the stack failure probability can be significantly reduced by properly decreasing the clamping forces for both designs, while adding a thick plate to the middle of the stack can effectively lower the probability of failure thus offering a superior stack mechanical performance and a prolonged stack life cycle. Such an approach to analyze stack failure can be readily accessed by flow battery engineers for design and assembly of commercial VFB stacks.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313077-fx1.jpg" width="466" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Pedro J. Corral-Vega, Luis M. Fernández-Ramírez, Pablo García-Triviño〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper describes and evaluates a hybrid propulsion system based on diesel generator and supercapacitors (SCs) as energy storage system (ESS) for a rubber tyre gantry (RTG) container crane, which currently operates within the yard of the Algeciras port terminal (Spain) powered by diesel electric generator for supplying the electric drives and motors (hoist and trolley). The SCs, which are connected to the DC bus through a bidirectional DC/DC converter, are controlled by a control strategy based on the DC-bus voltage. The SCs reference current is limited depending on their state-of-charge (SOC). All main components and control strategy of the RTG crane are modelled and simulated in SimPowerSystems. The current and hybrid configuration are simulated and compared under the real working cycle of the RTG crane. The results show the technical viability, the validity of the proposed control strategy, the improvements in the energy efficiency and diesel fuel consumption, and the economic viability of the hybrid propulsion system for the RTG crane.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Yadvinder Singh, Robin T. White, Marina Najm, Tylynn Haddow, Vivian Pan, Francesco P. Orfino, Monica Dutta, Erik Kjeang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mechanical degradation occurs in fuel cell membranes due to the dynamic environmental conditions of operational duty cycles, and is regarded as a critical determinant of fuel cell durability and lifetime. Imaging-based failure analysis is typically employed to characterize structural and morphological aspects of the degradation, and 3D visualization capability of X-ray computed tomography is effectively expanding the scope of this analysis. This work further leverages the additional non-destructive and non-invasive attributes of this visualization technique to capture 4D information pertaining to the evolution of mechanical degradation in fuel cell membranes. A custom fuel cell fixture is utilized to periodically track identical membrane locations during the course of its mechanical degradation, which is generated through an accelerated stress test. The predominant fatigue-driven membrane crack development process is found to proceed non-linearly in time and is spatially concentrated under the uncompressed channel regions. Membrane cracking location is shown to be strongly correlated with beginning-of-life MEA defects, namely, electrode cracks and delamination. 〈em〉In situ〈/em〉 crack propagation rates are quantified and the presence of a ‘crack closure’ effect during mechanical membrane degradation is demonstrated. Unlike crack initiation, crack propagation in the membranes does not appear to be significantly influenced by electrode morphology.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318312965-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Linna Sha, Ke Ye, Gang Wang, Jiaqi Shao, Kai Zhu, Kui Cheng, Jun Yan, Guiling Wang, Dianxue Cao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉NiCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 nanowire arrays grown on Ni foam (NiCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/NF) are synthesized by a simple template-free hydrothermal route followed by a thermal treatment in the air at 400 °C. The as-prepared Ni foam substrate exhibits homogeneous and porous nanowire arrays, which providing a number of active sites and electronic transmission channels for urea electrooxidation. The electroactivity of NiCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/NF electrode toward the oxidation of urea in alkaline solution is evaluated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) measurements. Results show that the as-obtained electrode delivers an outstanding electrocatalytic activity and stability for urea electrooxidation. The NiCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/NF electrode delivers a low open potential at 0.19 V versus Ag/AgCl with a corresponding current density of 570 mA cm〈sup〉−2〈/sup〉 in 5 mol L〈sup〉−1〈/sup〉 KOH and 0.33 mol L〈sup〉−1〈/sup〉 urea electrolytes. Meanwhile, detailed investigation is made for the electrocatalytic oxidation of urea by varying several reaction parameters, such as scan rate, urea and KOH concentrations. Benefiting from the unique structure and synergistic effects of Ni and Co, the NiCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/NF electrode exhibit superior electrocatalyst activity and is considered to be a promising candidate catalysis material for direct urea fuel cell.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Bruno S. Machado, Mohamed Mamlouk, Nilanjan Chakraborty〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A three-dimensional agglomerate model of an anion exchange membrane fuel cell has been developed and used to perform a parametric analysis of the effects of inlet relative humidity, ionomer water uptake, platinum loading, carbon content and ionomer volume fraction on the overall fuel cell performance. Improved cell performance has been obtained when the anode relative humidity was higher compared to the cathode resulting in a significant amount of water back diffusion, as well as higher oxygen partial pressure at the cathode enhancing the oxygen mass transport. Increasing the membrane water content positively affects the overall performance of the fuel cell because of the improvement of ionic conductivity. An increase in platinum loading has been found to have a positive impact on the fuel cell performance. Carbon loading influences the thickness of the catalyst layer, directly affecting concentration and Ohmic losses in the catalyst layer. An increase in the ionomer volume fraction enhances the transportation of ions and also the diffusion of membrane water through the membrane. A decrease in the volume fraction of ionomer in the catalyst layer leads to a reduction in the membrane water content and ion diffusion rate, thus deteriorating the overall performance of the fuel cell.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Wei Chen, Xingtian Yin, Meidan Que, Haixia Xie, Jie Liu, Chenhui Yang, Yuxiao Guo, Yutao Wu, Wenxiu Que〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Devices with printable carbon electrodes are promising directions for the commercialization of perovskite solar cells. Most of perovskite solar cells employ mesoporous device structures when using printable carbon as the counter electrodes. Here, we carry a comparative study of planar and mesoporous perovskite solar cells with carbon electrodes. The device efficiency is significantly reduced from 11.37% to 5.27% when the mesoporous TiO〈sub〉2〈/sub〉 film is removed from the device structure. Compared with the planar device, smaller carrier transport resistance and bigger carrier recombination resistance are demonstrated for the mesoporous device. Results suggest that the presence of mesoporous TiO〈sub〉2〈/sub〉 enables an efficient electron extraction from the perovskite absorber, which remits the serious carrier recombination in the hole transport layer free device due to the hole accumulation. Therefore, the electron extraction efficiency is crucial in these hole transport layer free devices with carbon electrodes. This study helps to develop further optimization of low temperature carbon-based perovskite solar cells for higher reproducibility and higher device performance.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318312667-fx1.jpg" width="463" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Yuqing Wang, Aayan Banerjee, Olaf Deutschmann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The co-electrolysis of CO〈sub〉2〈/sub〉 and H〈sub〉2〈/sub〉O in high temperature solid oxide electrolysis cells (SOECs) is a promising energy storage method for intermittent renewable energy sources. In this paper, a three-dimensional (3D) continuum model of a 3-kW 40-cell planar SOEC stack is employed to study the dynamic behavior and control strategy under variable working conditions. The dynamic responses of stack power, current density, output H〈sub〉2〈/sub〉/CO ratio and stack temperature are evaluated for a scaled real-time wind power input over a whole day. The fluctuation of the wind power input leads to SOEC stack temperature fluctuation, which illustrates the need for temperature control. Two representative cases with voltage step changes in both endothermic and exothermic operation modes are studied to predict the temperature control by the variation of excess air ratio. The effects of excess air ratio on both the steady-state temperature gradient and the transient temperature variation rate are analyzed in both cases. The temperature fluctuation is successfully controlled by applying an excess air ratio profile that changes with the wind power input.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Lin-Song Wu, Xiao-Ping Wen, He Wen, Hong-Bin Dai, Ping Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Crucial to enabling hydrous hydrazine as a viable fuel is the development of high-performance electrocatalysts. Herein, we report the synthesis of a palladium decorated porous nickel electrocatalyst using a combination of the dealloying and galvanic replacement methods. The obtained electrocatalyst shows outstanding catalytic activity and good long-term durability towards hydrazine oxidation. The mechanistic reason for the improved electrocatalytic performance is discussed based on the structural characterization and controlled experiments. Our study demonstrates that the electrocatalytic properties of catalyst can be improved by enhancing the number of active sites and its intrinsic activity.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318312527-fx1.jpg" width="322" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Yonghyun Lim, Hojae Lee, Soonwook Hong, Young-Beom Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nickel-samaria-doped ceria (Ni-SDC) nanocomposite anodes with various compositions are fabricated by co-sputtering technique. The film compositions are effectively controlled by adjusting the applied power to the SDC target while applying a constant power to the Ni target. The microstructure, crystallinity and electrical conductivity of the deposited films are analyzed and their optimal composition is investigated based on fuel cell performance and electrochemical impedance spectroscopy (EIS) analysis. Among various deposition conditions, the lowest polarization resistance is achieved at Ni-SDC 80W condition, which is attributed to the difference in the film composition and expected reaction site densities. Thin film fuel cells with the optimal nickel cermet anode are fabricated on a nanoporous supporting structure to achieve a high cell performance and compared with noble Pt electrode. The fuel cell with the optimal nickel cermet anode yields a maximum power density of 178 mW/cm〈sup〉2〈/sup〉 and polarization resistance of 0.55 Ω cm〈sup〉2〈/sup〉 at 450 °C, which is significantly improved from the reference Pt anode cell (113 mW/cm〈sup〉2〈/sup〉 and 1.69 Ω cm〈sup〉2〈/sup〉). Impedance analysis clearly demonstrates that the enhancement in the cell performance originates from the difference in the polarization resistance, resulting from the expanded reaction sites owing to the mixed ion electronic conducting characteristics of the nickel cermet nanocomposite anode.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Min Jung Kim, Seoung Jai Bai, Jae Ryoun Youn, Young Seok Song〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The photosynthetic activities of cyanobacteria have been employed in various energy related fields such as energy harvesting and water-splitting based energy conversion. However, the output powers obtained from the photo-bioelectrochemical cells have lower efficiency than those from other artificial materials. It is reported in this study that 〈em〉Synechococcus〈/em〉 sp.-iron oxide nanoparticles (γ-Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 and Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉)- neodymium iron boride magnet complexes enable great energy harvesting performance by both synergistic combination effect of the natural and artificial photocatalysts and formation of an effective electron transfer conduit to the electrode. A green LED bulb is turned on as the result of the energy harvesting. During the light illumination, electrons are transported through the electrode, yielding a peak power density of 0.806 and 0.534 W/m〈sup〉2〈/sup〉 for 〈em〉Synechococcus〈/em〉 sp.-γ-Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉- neodymium iron boride magnet and 〈em〉Synechococcus〈/em〉 sp.-Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉- neodymium iron boride magnet complexes, respectively. The difference in the power output arises from the distinct electrochemical interactions among the cell, iron oxide nanoparticles, and NdFeB depending on the type of the nanoparticles. The approach introduced in this study can boost solar energy harvesting remarkably by combining natural photocatalysts with artificial ones.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15–31 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volumes 410–411〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Qiming Bing, Wei Liu, Wencai Yi, Jing-yao Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Noble-metal-free catalysts are highly desirable for hydrogen generation from formic acid dehydrogenation. Herein, using first-principles density functional theory calculations, we design a series of nickel-anchored nitrogenated holey two-dimensional carbon structures (Ni〈sub〉x〈/sub〉@C〈sub〉2〈/sub〉N, x = 1–3) as formic acid dehydrogenation catalysts. For all Ni〈sub〉x〈/sub〉@C〈sub〉2〈/sub〉N surfaces, the formic acid dehydrogenation preferably proceeds via the formate pathway. The effective barrier continuously decreases for formic acid dehydrogenation while increases for hydrogen formation from Ni〈sub〉1〈/sub〉@C〈sub〉2〈/sub〉N to Ni〈sub〉3〈/sub〉@C〈sub〉2〈/sub〉N. The side reaction producing carbon monoxide and water via the carboxyl or formyl pathway cannot occur on Ni〈sub〉1〈/sub〉@C〈sub〉2〈/sub〉N or Ni〈sub〉2〈/sub〉@C〈sub〉2〈/sub〉N and is not preferred on Ni〈sub〉3〈/sub〉@C〈sub〉2〈/sub〉N, and thus, the Ni〈sub〉x〈/sub〉@C〈sub〉2〈/sub〉N catalysts possess excellent selectivity of hydrogen. Notably, the unsaturated nitrogen atom of substrate also participates in the reaction and exhibits synergetic effect with the nickel component in Ni〈sub〉1〈/sub〉@C〈sub〉2〈/sub〉N and Ni〈sub〉2〈/sub〉@C〈sub〉2〈/sub〉N. The Gibbs free energetic span analysis predicts that the order of reactivity is Ni〈sub〉2〈/sub〉@C〈sub〉2〈/sub〉N (0.79 eV) 〉 Ni〈sub〉1〈/sub〉@C〈sub〉2〈/sub〉N (0.87 eV) 〉 Ni〈sub〉3〈/sub〉@C〈sub〉2〈/sub〉N (1.23 eV), and the turnover frequency of Ni〈sub〉x〈/sub〉@C〈sub〉2〈/sub〉N is evaluated. The results are compared with the experimental and theoretical reports of some palladium-based catalysts. The present work suggests that the Ni〈sub〉x〈/sub〉@C〈sub〉2〈/sub〉N may be promising noble-metal-free catalysts for formic acid dehydrogenation with high performance and low cost.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314149-fx1.jpg" width="404" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Caihua Jiang, Shitong Wang, Yutong Li, Zhongtai Zhang, Zilong Tang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Multi-phase integration and structural hydration are effective material design strategies for advanced electrode materials with high capacity and fast lithiation. Herein, a novel layered-spinel lithium manganite hydrate is successfully synthesized through a one-step hydrothermal lithiation process. Structure characterizations, electrochemical properties, reaction mechanisms and kinetic analysis are investigated in detail. The layered-spinel coexistence, stable intercalated water, abundant interfaces/defects and mesoporous architectures comprising 2D nanosheets help to shorten the Li-ion transport pathway, promote electronic/ion conductivity, increase Li storage sites and maintain structural stability. With combined diffusion-controlled and pseudocapacitive reaction mechanisms, the layered-spinel lithium manganite hydrate exhibits superior electrochemical behaviors, showing great potentials for high-capability and ultrafast lithium storage. The comprehensive utilization of multi-phase integration and structural hydration promotes the diversity of material and structure systems, and further paves new way for the design of other high-performance electrode materials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314186-fx1.jpg" width="376" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Eric Matte, Gerald Holzlechner, Lars Epple, Detlef Stolten, Piero Lupetin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, cathode performance of cost-effective inert substrate-supported solid oxide fuel cells fabricated by a single step cosintering process is investigated. The polarization resistance of cosintered inert substrate-supported cathode symmetrical cells (ISC) is compared with the polarization resistance of electrolyte-supported symmetrical cells (ESC) prepared by post- and cosintering. ESC prepared by cosintering have similar polarization resistance than ESC prepared by post-firing due to the addition of pore formers. However, the implementation of a porous inert substrate increases the polarization resistance. Analysis of electrochemical impedance spectra could exclude a gas-phase diffusion limitation due to the porous substrate. Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) reveals an accumulation of zinc, magnesium and silicon on the inner pore surface of the cathode layer. Thermodynamic calculations confirm desorption of these elements from the silicate substrate during the cosintering. In addition, a zinc manganite spinel is detected in the cathode layer via confocal Raman spectroscopy, which indicates a reaction between the cathode material and zinc. The larger cathode polarization resistance of the inert substrate-supported cell is attributed to microstructural changes and the coverage of the cathode surface.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313764-fx1.jpg" width="433" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Hyunchul Kim, Dong-Seok Yang, Ji Hyun Um, Mahalingam Balasubramanian, Jaeseung Yoo, Hyunwoo Kim, Su Bin Park, Ji Man Kim, Won-Sub Yoon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For next generation Li-ion batteries, advanced electrode materials with high energy densities are mightily important issue. Since the partial oxidation of Sn with Li〈sub〉2〈/sub〉O to form SnO〈sub〉〈em〉x〈/em〉〈/sub〉 was demonstrated upon delithiation in SnO〈sub〉2〈/sub〉 anode, the additional conversion reaction has contributed that the theoretical capacity of SnO〈sub〉2〈/sub〉 can be extended from 783 to 1494 mAh g〈sup〉−1〈/sup〉. Herein, with the design of additional conversion reaction, we discuss key factors for high electrochemical performances of the SnO〈sub〉2〈/sub〉 anodes through comparative analysis between nano-structured mesoporous SnO〈sub〉2〈/sub〉 and conventional bulk SnO〈sub〉2〈/sub〉, based on synchrotron radiation-based techniques, quantitative analysis of extended X-ray absorption fine structure spectra, and bond strength calculation. In this way, we demonstrate that the mesoporous SnO〈sub〉2〈/sub〉 has a nano-engineered structure with the weakened Sn-O bond strength for inducing the enhanced reversible conversion reaction as well as the facilitated electrochemical reaction, and a void structure for relieving the severe volume changes during lithiation/delithiation. Consequently, excellent electrochemical performance through the additional reversible conversion reaction is obtained in the mesoporous SnO〈sub〉2〈/sub〉. Insight from this research enables important advance in the development of metal oxide-based anode materials by making irreversible reaction reversible, providing a realizable strategy for the design and creation of high-energy storage devices.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313867-fx1.jpg" width="327" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Lina Chen, Long Chen, Wei Zhai, Deping Li, Yunxiang Lin, Shirui Guo, Jinkui Feng, Lin Zhang, Li Song, Pengchao Si, Lijie Ci〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Li〈sub〉x〈/sub〉MnO〈sub〉2〈/sub〉 nanowires with controllable morphology and excellent electrochemical performance are synthesized by a hydrothermal method with tunable lithium contents. Both double layer capacitive process and diffusion-controlled Faradaic process play roles in the charging-discharging process. Aqueous Li-ion hybrid supercapacitors are assembled using Li〈sub〉x〈/sub〉MnO〈sub〉2〈/sub〉 nanowires as the positive electrode and activated carbon as the negative electrode. The hybrid devices deliver high energy density of 88.56 Wh kg〈sup〉−1〈/sup〉 and 25.2 Wh kg〈sup〉−1〈/sup〉 at the high power density of 151.8 W kg〈sup〉−1〈/sup〉 and 2155.8 W kg〈sup〉−1〈/sup〉, respectively. The device also shows superb cycling life with capacitance retention of 95.2% after 10,000 cycles and 85.2% after 20,000 cycles.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Shi Wang, Jingyu Li, Qingyuan Li, Jie Chen, Xu Liu, Zhinan Wang, Qinghui Zeng, Tong Zhao, Xiangfeng Liu, Liaoyun Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A topological structural polymer is designed and synthesized by sequential living polymerization of pinacol vinylboronate and poly(ethylene glycol) methyl ether methacrylate using hyperbranched polystyrene as the core. The as-synthesized polymer containing lithium salt is casted onto the ceramic electrostatic spinning film to prepare the composite solid polymer electrolyte. As predicted, the electrolyte shows a high ionic conductivity of 9.63 × 10〈sup〉−5〈/sup〉 S cm〈sup〉−1〈/sup〉 at room temperature, which likely due to the creation of conductive network on the surfaces of the nanowires. In addition, introduction of poly(pinacol vinylboronate) segments onto the hyperbranched polymer strongly improves the electrochemical stability (reaches 5.2 V) of the electrolyte in comparison to the one without poly(pinacol vinylboronate) chains. As a result, the LiFeO〈sub〉4〈/sub〉/Li cell using the electrolyte presents excellent long cycle stability at 50 °C (average discharge capacity of 130 mA h g〈sup〉−1〈/sup〉 with coulombic efficiency close to 100% over 800 cycles at 0.5 C) as well as very good cell performance at room temperature (discharge capacity reaches 162 mAh g〈sup〉−1〈/sup〉 with average coulombic efficiency of ∼100%). More importantly, we also confirm that the electrolyte can be applied to high-voltage cathode materials, such as LiCoO〈sub〉2〈/sub〉 and Li〈sub〉1.2〈/sub〉Mn〈sub〉0.5〈/sub〉Ni〈sub〉0.2〈/sub〉O〈sub〉2〈/sub〉-based cathodes, which also shows satisfactory cell performance.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313909-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Yiran Wang, Zhaoyong Jiao, Shuhong Ma, Yongliang Guo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The properties of C〈sub〉3〈/sub〉N/graphene heterostructures and their electrochemical performance serving as anodes for Li-ion batteries are systematically studied using density functional calculations. Present results demonstrate that C〈sub〉3〈/sub〉N/graphene exhibits a metallic behavior, favorable stability and ultrahigh stiffness, which are well maintained even under the applied strains and after lithium adsorption, ensuring the electrode's good electric conductivity and integrity against pulverization. Most particularly, it is predicted that C〈sub〉3〈/sub〉N/graphene possesses a maximum Li-storage theoretical capacity of 1079 mA h g〈sup〉−1〈/sup〉, low average open-circuit voltages (0.13 V) and Li-diffusion barrier (0.28 eV). These encouraging findings indicate that C〈sub〉3〈/sub〉N/graphene heterostructures can be appealing anode materials for Li-ion batteries.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Inci Donmez Noyan, Marc Dolcet, Marc Salleras, Andrej Stranz, Carlos Calaza, Gerard Gadea, Merce Pacios, Alex Morata, Albert Tarancon, Luis Fonseca〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper describes a specific route for the complete integration of a novel planar thermoelectric microgenerator (μTEG) that can operate under environmental conditions using commercial miniaturized heat exchangers. The proposed heat exchanger integration process is compatible with the fragility of planar micromachined silicon structures. The main structure of the μTEG is built around a micromachined silicon platform defined by silicon microfabrication technologies. Different silicon-based materials, such as bottom-up grown silicon and silicon-germanium nanowire arrays as well as top-down fabricated silicon microbeams are used as thermoelectric materials. μTEGs with those materials are characterized both before and after heat exchanger integration. The presence of the heat exchanger increases the μTEG performance significantly and power densities around 40 μW cm〈sup〉−2〈/sup〉 are obtained when placed on a heat source at 100 °C and exposed under natural convection to a surrounding ambient at room temperature.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313806-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Jeng-An Wang, Sheng-Chi Lin, Yu-Sheng Wang, Chen-Chi M. Ma, Chi-Chang Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a sticky copolymer of water-born polyurethane-potassium poly(acrylate) (WPU-PAAK) is designed for acting as not only a gel electrolyte but also a binder in manufacturing the carbon-based electrodes for flexible, quasi solid-state electrical double-layer capacitors (EDLCs). This copolymer has been successfully synthesized from potassium poly(acrylate) backbone cross-linked with water-born polyurethane. In comparison with the most common poly(vinylidene fluoride) (PVDF) binder, WPU-PAAK enhances the areal specific capacitance of activated carbon/carbon nanotube (AC/CNT)-coated electrode about 64% and over 100% at 1 and 10 mA cm〈sup〉−2〈/sup〉, respectively. More importantly, the areal specific capacitance of AC/CNT composites with the WPU-PAAK binder is directly proportional to their mass loading, revealing the perfect utilization of active materials. The quasi solid-state device of the sandwich type demonstrates a potential window of 1.4 V and a high device-areal specific capacitance of 122.43 mF cm〈sup〉−2〈/sup〉 at 1 mA cm〈sup〉−2〈/sup〉. This highly flexible electrical double-layer capacitor (over 95.6% areal specific capacitance retention at a bending angle of 180°) also delivers an energy density of 33.33 μWh cm〈sup〉−2〈/sup〉 at a power density of 0.7 mW cm〈sup〉−2〈/sup〉 with an excellent cycle life of 87.5% retention in the 10,000-cycle test.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S037877531831379X-fx1.jpg" width="272" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Yifan Chen, Qingqing Qiu, Dejun Wang, Yanhong Lin, Xiaoxin Zou, Tengfeng Xie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we present a new design for the development of quantum dot sensitized solar cells with a CuSe/Cu〈sub〉x〈/sub〉S substrate on F-doped tin oxide as the counter electrode. The best performing CuSe/Cu〈sub〉0.78〈/sub〉S counter electrode notably achieves a photoelectric conversion efficiency of 5.70% with a significant improvement in the J〈sub〉SC〈/sub〉 for the CdS/CdSe co-sensitized solar cells, superior to a cell with CuSe (4.80%) or Cu〈sub〉0.78〈/sub〉S (4.11%) as the counter electrodes. Two types of reverse barriers, including a positive reverse barrier and negative reverse barrier, at the interface between the Cu〈sub〉x〈/sub〉S and CuSe are investigated using solid-state measurements from a dark current–voltage test. The transient photovoltage responses and Kelvin probe measurements further demonstrate reduction of the positive reverse barrier between the CuSe and Cu〈sub〉x〈/sub〉S interface with increasing Cu/S ratios of Cu〈sub〉x〈/sub〉S (x = 0.52–0.78), which is beneficial to the electron transfer from Cu〈sub〉x〈/sub〉S to CuSe. The electrochemical catalytic activity and stability of the CuSe/Cu〈sub〉x〈/sub〉S counter electrodes are verified with electrochemical impedance spectroscopy, tafel polarization and cyclic voltammetry results, which suggest that CuSe/Cu〈sub〉x〈/sub〉S counter electrodes have promising applications in solar cells.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313788-fx1.jpg" width="258" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 28 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 414〈/p〉 〈p〉Author(s): Tunc Catal, Aykut Kul, Vildan Enisoglu Atalay, Hakan Bermek, Selma Ozilhan, Nevzat Tarhan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Detection and partial degradation of the cocaine metabolite benzoylecgonine in synthetic and real human urine is accomplished using single-chamber air-cathode microbial fuel cells. Microbial fuel cells generate voltage in the range of 0.2–0.26 V using synthetic urine or real human urine obtained from both cocaine users and drug-free individuals. Concentrations of benzoylecgonine up to 1000 ng/mL are treated in the fuel cells, and electricity generation is decreased with respect to increasing concentrations of benzoylecgonine. Power density, current density, chemical oxygen demand removal and total carbohydrate removal data confirm that, in comparison to the synthetic urine, fuel cell performance decreases using benzoylecgonine-containing human urine as the medium. In the fuel cells, benzoylecgonine levels decrease by 14% in 24 h of incubation, as determined by mass spectrometry results. According to the computational chemistry analysis, cation form 2 of the benzoylecgonine might limit transfer of electrons from the microorganisms to anode. In conclusion, microbial fuel cell technology is shown to exhibit a potential for use as biosensors for detection and quantification of cocaine metabolite benzoylecgonine in real human urine.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Ying Zhang, Qi Song, Tingli Wang, Qinfu Zhao, Ronglan Zhang, Jianshe Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Three kinds of morphology precursors were synthesized by three different hydrothermal assisted coprecipitation methods and calcined to obtain the nanoscale cathode materials Li〈sub〉2〈/sub〉MnO〈sub〉3〈/sub〉·LiMO〈sub〉2〈/sub〉 (M = Mn, Co, Ni) for lithium ion battery. The difference in dispersed ions, solvothermal solvents and calcination for precursors may lead to different nucleation kinetics, and further lead to different morphologies for precursors. Interestingly, the precursors form the battery cathode materials with similar morphologies in different crystallographic directions. In addition, a theoretical simulation has been carried out to confirm that lithium ions migrate activation barrier is the lowest along the b-axis, while the hexagonal sheet precursor may prefer to form a material with its (010) crystal face preferential exposure. The theoretical results can further guide to prepare high performance Li〈sub〉2〈/sub〉MnO〈sub〉3〈/sub〉·LiMO〈sub〉2〈/sub〉 cathode materials for lithium ion batteries.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314204-fx1.jpg" width="411" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Ryohei Morita, Kazuma Gotoh, Mouad Dahbi, Kei Kubota, Shinichi Komaba, Kazuyasu Tokiwa, Saeid Arabnejad, Koichi Yamashita, Kenzo Deguchi, Shinobu Ohki, Tadashi Shimizu, Robert Laskowski, Hiroyuki Ishida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Phosphorus is a promising material for the electrode in sodium ion batteries (NIBs). In this study, the states of Na〈sub〉x〈/sub〉P〈sub〉y〈/sub〉 compounds synthesized by thermochemical reaction and electrochemical sodiation were compared using solid state 〈sup〉23〈/sup〉Na magic angle spinning (MAS) NMR, 〈sup〉23〈/sup〉Na multiple quantum (MQ) MAS NMR, and 〈sup〉31〈/sup〉P MAS NMR. The NMR signals in thermochemically synthesized Na〈sub〉x〈/sub〉P〈sub〉y〈/sub〉 compounds (Na〈sub〉3〈/sub〉P, NaP, Na〈sub〉3〈/sub〉P〈sub〉7〈/sub〉, Na〈sub〉3〈/sub〉P〈sub〉11〈/sub〉, NaP〈sub〉7〈/sub〉) are assigned in reference to theoretical chemical shifts, based on first-principles calculations. Furthermore, the NMR signals in electrochemically prepared Na〈sub〉x〈/sub〉P〈sub〉y〈/sub〉 compounds after two sodiation/desodiation cycles are ascribed to Na〈sub〉3〈/sub〉P compounds and three amorphous compositions. The amorphous compounds ascribed to Na〈sub〉1−α〈/sub〉P (0 〈 α 〈 1), Na〈sub〉2−β〈/sub〉P (0 〈 β 〈 1), and Na〈sub〉3−γ〈/sub〉P (0 〈 γ 〈 1) are formed below 0.58 V in the charge and discharge process. These Na〈sub〉3〈/sub〉P and the amorphous phases overlapped in the range from 0.20 V (sodiation process) to 0.58 V (desodiation process). 〈sup〉23〈/sup〉Na and 〈sup〉31〈/sup〉P NMR spectra reveal reversible sodiation and desodiation processes in the third cycle.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Baobing Huang, Xiang Hu, Yuchuan Liu, Wei Qi, Zailai Xie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Effective integration of CNTs and heteroatom-doped graphene can produce a new functional carbons that combines the extraordinary properties of heteroatom-doped graphene (e.g., catalytic activity, and huge exposed field) with those of CNTs (e.g., mechanical stability, and high electronic conductivity). Herein, we report a straightforward method to manufacture a metal-free, hierarchically porous and N/S co-doped CNT-graphene 3D framework 〈em〉via〈/em〉 one-step pyrolysis of the guanine-sulfate and OCNTs. The usage of guanine-sulfate as carbon precursor can yield very regular (2D nanosheet) and in situ nitrogen-doped carbons. By combining with OCNTs, the as-obtained graphene is found to strongly couple with the surface of CNTs, achieving the uniform distribution of both components. Such 3D hybrid shows high activity toward a set of important electrochemical reactions and high-performance in Zn-air batteries. Systematic electrochemical studies indicate the indispensability of both the optimal nitrogen configuration and well-developed porosity for excellent ORR/OER/HER performance. The amount of pyridinic-N and graphitic-N, rather than the total nitrogen content, has a more positive effect on ORR activity, particularly for the onset potential; while the favorable pore size distributions might guarantee a much well-developed diffusion-limited current region and considerable diffusion-limited current value. These results undoubtedly could provide meaningful guidance to develop highly efficient electrocatalysts.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313983-fx1.jpg" width="322" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Gustav Wilhelm Sievers, Jacob R. Bowen, Volker Brüser, Matthias Arenz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanostructuring of electrocatalysts is an important aspect of catalyst design as catalytic performance depends not only on the specific activity (reaction rate per surface area), but also on the dispersion of the catalyst. We present an industrially compatible, but effective preparation method for support-free nanostructured catalyst layers. Alternating sputtering was used to prepare heterogeneous Pt〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Cu templates ranging from 95 up to 99.5 at. % Cu. These templates were then electrochemically leached to form a nanostructured Pt〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Cu network and benchmarked with respect to the oxygen reduction reaction. It is shown that the templates with lower Cu:Pt ratios exhibit the highest initial specific activity but have a relatively low electrochemically active surface area. Subjecting the samples to extended accelerated stress tests, it is found that the support-free nanostructured Pt〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Cu networks are relatively resistant to high potential cycling, which can be explained by the lack of carbon corrosion. The loss in electrochemical surface area thereby depends on the initial Pt content. The specific oxygen reduction activity, however, approaches the value of bulk Pt. Although this decrease is not desirable, still an (specific) activity improvement of two to four times as compared carbon supported nanoparticles can be preserved.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313958-fx1.jpg" width="391" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Ying Zhao, Peter Stein, Yang Bai, Mamun Al-Siraj, Yangyiwei Yang, Bai-Xiang Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Investigations on the fast capacity loss of Lithium-ion batteries (LIBs) have highlighted a rich field of mechanical phenomena occurring during charging/discharging cycles, to name only a few, large deformations coupled with nonlinear elasticity, plastification, fracture, anisotropy, structural instability, and phase separation phenomena. In the last decade, numerous experimental and theoretical studies have been conducted to investigate and model these phenomena. This review aims, on one hand, at a comprehensive overview of the approaches for modeling the coupled chemo-mechanical behavior of LIBs at three different scales, namely the particle, the electrode, and the battery cell levels. Focus is thereby the impact of mechanics on the cell performance and the degradation mechanisms. We point out the critical points in these models, as well as the challenges towards resolving them. Particularly, by outlining the milestones of theoretical and numerical models, we give a step-by-step instruction to the interested readers in both electrochemical and mechanical communities. On the other hand, this review aims to facilitate the knowledge transfer of mechanically coupled modeling to the study of all-solid-state batteries, where the mechanical issues are expected to play even more diverse and essential roles due to the additional mechanical constraintimposed by the solid electrolytes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Jian-Gan Wang, Huanyan Liu, Rui Zhou, Xingrui Liu, Bingqing Wei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Two-dimensional MoS〈sub〉2〈/sub〉 is a promising anode material for Li-ion batteries, but suffers from poor electrochemical activity and stability. Herein, a facile approach for the controlled synthesis of onion-like nanospheres organized by carbon encapsulated MoS〈sub〉2〈/sub〉 nanosheets is developed through a simple polymerization and sulfidation/carbonation process. Mo-containing polyoxometalate is demonstrated to enable polymerization of polypyrrole accompanying with uniform encapsulation of Mo-nanoclusters. The hybrid precursor confines the growth of few-layer MoS〈sub〉2〈/sub〉 nanosheets (≤5 layers) into N-doped carbon framework, which is of great benefit in enhancing the electrical conductivity and structural integrity. As a result, the nanospherical MoS〈sub〉2〈/sub〉@C hybrid electrode manifests high Li-ion storage capacity (1119 mAh g〈sup〉−1〈/sup〉 at 0.1 A g〈sup〉−1〈/sup〉), excellent rate capability (616 mAh g〈sup〉−1〈/sup〉 at 2 A g〈sup〉−1〈/sup〉), and long cycling stability. The substantial improvement is rationalized by fast electrode kinetics and great pseudocapacitive contribution. The present work may offer a powerful engineering strategy of MoS〈sub〉2〈/sub〉@C nanomaterials for Li/Na-ion batteries and electrocatalysts.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S037877531831406X-fx1.jpg" width="313" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Hongwei Mi, Xiaodan Yang, Fang Li, Xiaoqin Zhuang, Chunxia Chen, Yongliang Li, Peixin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Silicon anode suffers from poor intrinsic conductivity and dramatic volume change during discharge/charge process, which hinders its commercialization for high energy density lithium-ion batteries. To address these challenges, silicon-sodium alginate-polyaniline composites are rationally designed and synthesized via in-situ polymerization. A hydrogen bond self-healing process occurs during lithiation and delithiation to accommodate the strong volumetric modification, so that the composites perform excellent electrochemical performance, with a capacity of 1099.5 mAh·g〈sup〉−1〈/sup〉 after 200 cycles at the current density of 1.0 A·g〈sup〉−1〈/sup〉. In view of the density functional theory calculations, the synergy effect of sodium alginate and polyaniline enhances the hydrogen bonding of the silicon and polymers, increases the electron transport capability, and results in excellent electrical, mechanical integrity and conductivity of the electrodes. Our work not only provides a facile procedure to prepare unique conducting three dimensional network structured composites as a commercial anode but also reveals the mechanism that the silicon nanoparticles avoids electrode pulverization via hydrogen bonding self-healing process.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318312758-fx1.jpg" width="220" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): S. Gopalakrishnan, G.M. Bhalerao, K. Jeganathan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report the fabrication of hybrid Si nanowires @ g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 nanosheets based photocathode using metal assisted chemical etching and facile liquid exfoliated process. The g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 nanosheets on Si nanowires form hybrid heterojunction photocathode, which exhibits an enhanced photon induced water reduction activity enabling higher photocurrent density of 22 mA cm〈sup〉−2〈/sup〉 with applied bias photocurrent conversion efficiency of 4.3% under visible light irradiation. The onset potential of cathodic photocurrent is positively shifted from 41 to 420 mV vs. RHE with the short circuit current density, J〈sub〉sc〈/sub〉 of 0.50 mA cm〈sup〉−2〈/sup〉 owing to superior charge transport in hybrid photocathode as compared to pristine Si nanowires for hydrogen evolving reaction at pH∼7. The electrochemical impedance spectroscopy measurement elucidates the interface layer of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 nanosheets form hybrid heterojunction with Si nanowires that result significant increment in solar water reduction activity owing to low charge transferred resistance with high life time of excited electrons in conduction band. This strategy may open to design a new low cost stable hybrid heterostructure photocathode for solar induced water reduction.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313855-fx1.jpg" width="248" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Libin Zeng, Xinyong Li, Shiying Fan, Mingmei Zhang, Zhifan Yin, Moses Tadé, Shaomin Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Developing low-energy and high-efficiency photoelectrocatalysts towards hydrogen evolution reaction is one of the frontier technologies capturing intensive research enthusiasm. In this work, a sustainable solar-driven microbial fuel cell is successfully constructed to synthesize rich edge sites of MoS〈sub〉2〈/sub〉 nanomaterials and 〈em〉in situ〈/em〉 utilize dual electrons mode for hydrogen generation under visible light illumination (〉420 nm). For this photo-driven coupling system, the continuous formation of MoS〈sub〉2〈/sub〉 catalyst is more beneficial for efficient hydrogen generation without external bias assistance. Such unique preparation method endows the system to possess more active edge sites for MoS〈sub〉2〈/sub〉 exposure, and promotes the obtained materials to exhibit super-hydrophilic behavior. Additionally, the introduction of MoS〈sub〉2〈/sub〉 semiconductor could cooperate with bio-electrons to dramatically hinder the recombination of photo-excited electron-hole pairs, leaving more opportunities for photo-electrons to participate hydrogen evolution reaction under the bioelectric field. Simultaneously, the constructed MoS〈sub〉2〈/sub〉 based electrode performs excellent photoelectrochemical performance (the onset overpotential only ∼36 mV 〈em〉vs.〈/em〉 SHE, Tafel slope of 53 mV per decade) and hydrogen evolution activities for hydrogen production with 0.003 m〈sup〉3〈/sup〉 m〈sup〉−3〈/sup〉 min〈sup〉−1〈/sup〉 rate. This work not only leads to a promising approach for the preparation of high efficient photoelectrocatalysts, but also highlights the potential strategy for diverse applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314058-fx1.jpg" width="346" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Siyuan Chen, He Duan, Long Zhao, Yanming Zhao, Asha Gupta, Quan Kuang, Qinghua Fan, Xinxuan Zeng, Huangzhong Yu, Youzhong Dong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The novel CeVO〈sub〉3〈/sub〉 anode material is synthesized successfully by simple sol-gel method. The crystal structure is determined by the X-ray diffraction, where the CeVO〈sub〉3〈/sub〉 possesses a stable framework and a good lithium-ion migration pathway. The corresponding electrochemical measurement shows that pure CeVO〈sub〉3〈/sub〉 presents a low reversible discharge capacity and poor rate performance due to the low electronic conductivity. In order to improve the electrochemical properties, the carbon-coated CeVO〈sub〉3〈/sub〉 samples are also prepared choosing sucrose as carbon source with 9.5% carbon content. The added carbon inhibits the particle growth and increases the conductivity. By carbon-coating, the corresponding electronic conductivity of the CeVO〈sub〉3〈/sub〉 is increased by one order of magnitude and the lithium diffusion coefficient is increased from 6.55 × 10〈sup〉−11〈/sup〉 cm〈sup〉2〈/sup〉 s〈sup〉−1〈/sup〉 to 2.26 × 10〈sup〉−10〈/sup〉 cm〈sup〉2〈/sup〉 s〈sup〉−1〈/sup〉, resulting in the improvement of discharge specific capacity and rate performance. In addition, using In-situ XRD method, we determine the Li ions insertion/extraction mechanism of the CeVO〈sub〉3〈/sub〉 material which can be interpreted as a solid-solution behavior. Finally, using nudged elastic band method, we calculate the possible migration paths for lithium diffusion in CeVO〈sub〉3〈/sub〉 crystal which most likely prefers to along the diagonal direction of 〈em〉z〈/em〉 axis and 〈em〉x〈/em〉 axis.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314046-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Jieting Ding, Palanisamy Kannan, Peng Wang, Shan Ji, Hui Wang, Quanbing Liu, Hengjun Gai, Fusheng Liu, Rongfang Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Designing a novel, highly efficient earth-abundant, and low cost electrocatalyst is a key for direct hydrazine fuel cell (DHFC) applications. Electrocatalyst plays an eminent role in enhancing the performance of DHFC, a promising tool to produce electricity without CO〈sub〉2〈/sub〉 emission. Herein, we report a salt-template based synthesis of manganese oxide (MnO) nanoparticles integrated nitrogen-doped network-like carbon (MnO/N-C) nanocomposites and demonstrated their catalytic performance towards electrochemical oxidation of hydrazine for the first time. The MnO nanoparticles (3.7 nm size) are not only uniformly distributed onto the entire N-C composite surface, but also having enormous porous structure with large active surface area of 885 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉 and external surface area of 678 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉, which plays a majestic role in hydrazine oxidation reaction. Interestingly, MnO/N-C nanocomposite displays significantly higher electrocatalytic performance towards hydrazine oxidation than the N-C and MnO catalysts. In addition, the electrocatalytic performance of MnO/N-C nanocomposite appeared even after 3000 cycles, demonstrating an exceptional stability of MnO/N-C catalyst. The improved electrocatalytic efficiency of MnO/N-C nanocomposite originates from the synergetic physicochemical properties of MnO and N-C, which offers large active sites for the catalytic reactions and rapidly facilitates electrolyte diffusion for DHFC applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314010-fx1.jpg" width="389" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Chengshang Zhou, Zhigang Zak Fang, Pei Sun, Lei Xu, Yong Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Catalyzed magnesium hydride is suggested as a potential absorbent material for hydrogen separation, purification, and other relevant applications. The present study reports an investigation on selective hydrogen absorption using ball-milled VTiCr-catalyzed MgH〈sub〉2〈/sub〉 from a gaseous mixture. Temperature oscillation absorption method, thermogravimetric analysis and differential scanning calorimeter techniques are utilized to characterize the VTiCr-catalyzed MgH〈sub〉2〈/sub〉, demonstrating a reversible capacity up to 4 wt%H when the temperature is oscillated between 150 and 350 °C. When the hydrogen partial pressure is increased from 0.04 to 0.4 bar the reaction (dehydrogenation and hydrogenation) temperatures increase, and so do the reversible hydrogen capacities. The reaction kinetics are stable during the first 10 cycles. Transmission electron microscopy analysis shows that the VTiCr catalyst is a few nanometers in size and is dispersed uniformly in MgH〈sub〉2〈/sub〉 matrix. The results of this study demonstrate that nano-VTiCr catalyzed MgH〈sub〉2〈/sub〉 can readily react with low-pressure hydrogen and cycle in the mixture atmosphere.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313995-fx1.jpg" width="283" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Homen Lahan, Shyamal K. Das〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉While addressing the question of Al〈sup〉3+〈/sup〉 ion intercalation/deintercalation in MoO〈sub〉3〈/sub〉, we unravel that Al〈sup〉3+〈/sup〉 ion preferentially intercalates in MoO〈sub〉3〈/sub〉 in certain aqueous electrolytes. The Al〈sup〉3+〈/sup〉 ion electrochemistry in MoO〈sub〉3〈/sub〉 shows stark contrasting characteristics in different aqueous electrolytes. Although very high initial Al〈sup〉3+〈/sup〉 ion storage capacity of 680 mAhg〈sup〉−1〈/sup〉 is observed, a stable discharge capacity of approximately 170 mAhg〈sup〉−1〈/sup〉 is attained after 20th cycle over the measured time (350〈sup〉th〈/sup〉 cycle) at a specific current of 2.5 Ag〈sup〉-1〈/sup〉 (5 mA cm〈sup〉−2〈/sup〉) in AlCl〈sub〉3〈/sub〉 aqueous electrolyte. AlCl〈sub〉3〈/sub〉 aqueous electrolyte exhibits superior benefits than Al〈sub〉2〈/sub〉(SO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉 and Al(NO〈sub〉3〈/sub〉)〈sub〉3〈/sub〉 aqueous electrolytes in terms of offering higher Al〈sup〉3+〈/sup〉 ion storage capacity, long-term stability, capacity retention and minimized polarization.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Maria Grazia Insinga, Roberto Luigi Oliveri, Carmelo Sunseri, Rosalinda Inguanta〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Despite Lead Acid Battery (LAB) is the oldest electrochemical energy storage system, diffusion in the emerging sectors of technological interest is inhibited by its drawbacks. The principal ones are low energy density and negative plate sulphating on high rate discharging. In this work, it is shown the possibility of overcoming such drawbacks by using nanostructured lead as a negative electrode. Lead nanowires (NWs) were fabricated by electrochemical deposition in template, which is an easy, cheap, and easily scalable process. Their morphology and crystal structure have been characterized by electron microscopy and X-ray diffraction, respectively. An electrochemical cell simulating LAB has been assembled with PbO〈sub〉2〈/sub〉 as a counter electrode and an AGM separator, both from commercial battery. Cycling tests were conducted at 10C-rate, setting the cut-off voltage on discharging at 1.2 V. For comparison, also cycling tests at 1C-rate have been carried out, in otherwise identical conditions. At both C-rates, performances in terms of cycling efficiency and lifetime were found a lot better than those of current LABs. The high porosity formed under cycling at 10C-rate provides a reliable explanation of the results.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313843-fx1.jpg" width="217" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Jing Qi, Yunfeng Zhai, Jean St-Pierre〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effects of single, binary and ternary contaminant mixtures containing propene (C〈sub〉3〈/sub〉H〈sub〉6〈/sub〉), acetonitrile (CH〈sub〉3〈/sub〉CN), and bromomethane (CH〈sub〉3〈/sub〉Br) on proton exchange membrane fuel cells have been studied. Changes in polarization curves, electrochemical impedance spectroscopy spectra, electrochemical catalyst surface areas by cyclic voltammetry, and hydrogen crossover through the membrane by chronoamperometry are used to define the extent of recovery and irrecoverable losses after the contamination period and to understand the contaminant interactions. CH〈sub〉3〈/sub〉CN in the contaminant mixture mitigates the decrease in oxygen reduction reaction kinetics and the increase in oxygen and water mass transport resistance, while C〈sub〉3〈/sub〉H〈sub〉6〈/sub〉 speeds up the above situations. The hydrolysis of CH〈sub〉3〈/sub〉CN results in the formation of ammonium ions, which exchange with membrane protons, leading to an increase in the membrane resistance. CH〈sub〉3〈/sub〉Br increases the decomposition of the Nafion〈sup〉®〈/sup〉 ionomer. Bromide accumulation on the catalyst surface leads to large catalyst area losses for the mixtures containing CH〈sub〉3〈/sub〉Br. Competitive adsorption on Pt active sites exists between CH〈sub〉3〈/sub〉CN and CH〈sub〉3〈/sub〉Br. However, there is noncompetitive adsorption between C〈sub〉3〈/sub〉H〈sub〉6〈/sub〉 and CH〈sub〉3〈/sub〉Br or CH〈sub〉3〈/sub〉CN.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Chuan Cheng, Ross Drummond, Stephen R. Duncan, Patrick S. Grant〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Li-ion battery cathodes based on LiFePO〈sub〉4〈/sub〉 are fabricated by a layer-by-layer spray printing method with a continuous through thickness gradient of active material, conductive carbon, and binder. Compared with cathodes with the more usual homogeneous distribution, but with the same average composition, both C-rate and capacity degradation performance of the graded electrodes are significantly improved. For example at 2C, graded cathodes with an optimized material distribution have 15% and 31% higher discharge capacities than sprayed uniform or conventional slurry cast uniform cathodes, and capacity degradation rates are 40–50% slower than uniform cathodes at 2C. The improved performance of graded electrodes is shown to derive from a lower charge transfer resistance and reduced polarization at high C-rates, which suggests a more spatially homogeneous distribution of over-potential that leads to a thinner solid electrolyte interphase formation during cycling and sustains improved C-rate and long-term cycling performance.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313727-fx1.jpg" width="494" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Di Tian, Xiaofeng Lu, Yun Zhu, Meixuan Li, Ce Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metal-organic framework nanosheets draw continuous attention in energy storage areas. In this work, for the first time, a facile strategy is developed to grow metal-organic framework nanosheets on electrospun nanofibers as supercapacitor electrode materials, exhibiting a high capacitance of 702.8 F g〈sup〉−1〈/sup〉 at a current density of 0.5 A g〈sup〉−1〈/sup〉 and excellent cycling stabilities over 10000 cycles. Through a specific carbonization process, the metal-organic framework based hybrids are preserved to produce a porous metal doped carbon material with the improved rate performance and a great prospect for cathode materials. Furthermore, an asymmetric solid-state supercapacitor device is assembled using the metal-organic framework based hybrids and metal doped carbon materials as anode and cathode materials, respectively. The maximum energy density of 51.4 Wh kg〈sup〉−1〈/sup〉 with a power density of 1500.1 W kg〈sup〉−1〈/sup〉 is achieved, which is superior to many previous reports, revealing a promising prospect for the novel high-performance asymmetric supercapacitor.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S037877531831365X-fx1.jpg" width="298" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Christopher H. Lee, Joseph A. Dura, Amy LeBar, Steven C. DeCaluwe〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The solid electrolyte interphase (SEI) remains a central challenge to lithium-ion battery durability, in part due to poor understanding of the basic chemistry responsible for its formation and evolution. In this study, the SEI on a non-intercalating tungsten anode is measured by operando neutron reflectometry and quartz crystal microbalance. A dual-layer SEI is observed, with a 3.7 nm thick inner layer and a 15.4 nm thick outer layer. Such structures have been proposed in the literature, but have not been definitively observed via neutron reflectometry. The SEI mass per area was 1207.2 ng/cm〈sup〉2〈/sup〉, and QCM provides insight into the SEI formation dynamics during a negative-going voltage sweep and its evolution over multiple cycles. Monte Carlo simulations identify SEI chemical compositions consistent with the combined measurements. The results are consistent with a primarily inorganic, dense inner layer and a primarily organic, porous outer layer, directly confirming structures proposed in the literature.〈/p〉 〈p〉Further refinement of techniques presented herein, coupled with additional complementary measurements and simulations, can give quantitative insight into SEI formation and evolution as a function of battery materials and cycling conditions. This, in turn, will enable scientifically-guided design of durable, conductive SEI layers for Li-ion batteries for a range of applications.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S037877531831348X-fx1.jpg" width="483" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 28 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 414〈/p〉 〈p〉Author(s): Xianjun Wei, Ji-Shi Wei, Yongbin Li, Hongli Zou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An efficient and economic approach for sustainable production of hierarchically interconnected porous carbons are designed and fabricated through the pyrolysis of Rhus typhina fruits and followed by KOH activation to create micropores or mesopores on the nano-sheet wall of macropores. The related N-doped carbon consists of a plenty of micropores and owns high specific surface area (up to 2675 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉), resulting in high performances for supercapacitors, such as ultrahigh specific capacitance (568 F g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉), remarkable rate capability (310 F g〈sup〉−1〈/sup〉 at 20 A g〈sup〉−1〈/sup〉, 282 F g〈sup〉−1〈/sup〉 at even 30 A g〈sup〉−1〈/sup〉 current density) and good long-term stability (capacitance retention of 99% after 10000 cycles at 30 A g〈sup〉−1〈/sup〉) in 1 mol L〈sup〉−1〈/sup〉 H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉. Moreover, the carbon derived from Rhus typhina fruits demonstrates 474 F g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉, 281 F g〈sup〉−1〈/sup〉 at 30 A g〈sup〉−1〈/sup〉, and capacitance retention of 92% after 10000 cycles at 30 A g〈sup〉−1〈/sup〉 in 6 mol L〈sup〉−1〈/sup〉 KOH electrolyte. This novel and sustainable biomass-derived carbon material holds a bright future for fabricating high energy supercapacitors.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314150-fx1.jpg" width="351" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Lubing Wang, Sha Yin, Jun Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The safety design of systems using lithium-ion batteries (LIBs) as power sources, such as electric vehicles, cell phones, and laptops, is difficult due to the strong multiphysical coupling effects among mechanics, electrochemistry and thermal. An efficient and accurate computational model is needed to understand the safety mechanism of LIBs and thus facilitate fast safety design. In this work, a detailed mechanical model describing the mechanical deformation and predicting the short-circuit onset of commercially available 18650 cylindrical battery with a nickel cobalt aluminum oxide (NCA) system is established for the first time. The mechanical properties of anode, cathode, and separator are characterized. Based on the experiment results, the constitutive models of component materials are established and validated through numerical simulations. A detailed computational model including all components (i.e., separator, anode, cathode, winding, and battery casing) is then developed by evaluating four typical mechanical-loading conditions. Short-circuit criteria are subsequently established based on the separator failure, thereby enabling the mechanical model to predict the short circuit electrochemically. Results show that the model can describe LIB behaviors from mechanical deformation to internal short circuit. Results provide a powerful tool for the safety design of LIBs and related engineering systems.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314101-fx1.jpg" width="290" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Shiro Tanaka, Arnaud G. Malan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effect of the metal-gas diffusion layer (M-GDL) on the performance of a proton exchange membrane fuel cell (PEMFC) was investigated by numerically simulating selected parameters. Even though the ability of the M-GDL to outperform the conventional GDL is well known, it is necessary to optimise the design parameters of the M-DGL. This is to address its inefficient gas and electron transport due to the inherent heterogeneous structure. This paper presents the use of numerical simulation to quantify (a) the effect of the size of the pores and (b) width of the frame comprising the structure of a porous M-GDL in a PEMFC. A mechanical – electrical – electrochemical – fluid dynamics coupling model was utilised for this study involving an isothermal and single-phase simulation. The best cell performance was estimated as 0.63 V at 1.5 A cm〈sup〉−2〈/sup〉 with the optimised M-GDL design, under the fully humidified condition with 30 μm-thick Nafion. This constitutes a 9.4% improvement in cell performance.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S037877531831396X-fx1.jpg" width="278" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Saidatul Sophia Sha'rani, Ebrahim Abouzari-Lotf, Mohamed Mahmoud Nasef, Arshad Ahmad, Teo Ming Ting, Roshafima Rasit Ali〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The search of new membranes for vanadium redox flow battery with low vanadium ions permeation rates, high ion conductivity, excellent proton conductivity, low area resistance, chemical stability, and low cost is on a soaring demand. In this work, a simple modification method is applied to improve the performance of commercially available low-cost membranes by applying several polyelectrolytes layers. Particularly, graphene-containing commercial perfluorinated sulfonic acid membrane of GN212C with a thickness of 33 μm is modified by introducing alternate layers of positively charged poly(diallyldimethylammonium chloride) and negatively charged poly(sodium styrene sulfonate). Microscopy and spectroscopy investigations indicate that the polyelectrolytes layers are successfully deposited on the membrane surface. The effects of the layer composition and number of bilayers are evaluated with regard to vanadium ion permeability, proton conductivity and battery performance. The modified membranes exhibit an improved vanadium (VO〈sup〉2+〈/sup〉) barrier property, which enhances the VRFB single cell performance in terms of coulombic efficiency and energy efficiency compared to pristine GN212C and Nafion 117 membranes. The overall results suggest that the bi-ionically modified membrane is a potential candidate for application in flow battery despite its small thickness.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313879-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Liwen Zhang, Qiuquan Guo, Rosaiah Pitcheri, Yi Fu, Jiangsheng Li, Yejun Qiu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Self-support silver nanofibers with excellent electrocatalytic performance for oxygen reduction reaction (ORR) are successfully fabricated through a hybrid method combining an electrospinning process with an electroplating technique. This nanofiber-based catalyst demonstrated superior long-term stability and an unusually high methanol-tolerant effect that its ORR activity was enhanced, instead of lessened in 3 M methanol. The impact of microstructure and crystal facet on ORR activity is examined through quantifying the performance of the catalysts by electrochemical measurements. Through tuning the synthesis parameters, the onset potential, half-wave potential, and peak potential of 1.041 V, 0.848 V, and 0.864 V are achieved for the silver nanofibers with thorny structure, even superior to those of commercial Pt/C catalyst. Such excellent performance is attributed to two major factors, the micro morphology, i.e. thorn-on-fiber structure, and the crystal facet. The special thorny structure leads to the accumulation of electrons on the tip to act as highly active sites and better confinement of the oxygen between thorns, while the high ratio of (110) facets on the tip favors high catalytic activity. This kind of low-cost silver nanofiber-based catalyst exhibits a highly beneficial prospect as a potential alternative catalyst for oxygen reduction reaction.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313971-fx1.jpg" width="265" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Omar Muneeb, Isabel Chino, Albert Saenz, John L. Haan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A grand challenge for optimization of fuel cells is reduction in catalyst cost due to the prolific use of precious metals. The development of alkaline direct liquid fuel cells has reduced dependence on Pt, but it has not eliminated the use of precious metals such as Pd. In this work, we demonstrate two ascorbate fuel cells that contain carbon black nanoparticles as the electrodes (both anode and cathode) to produce impactful power. The first fuel cell is constructed with an anion exchange membrane, a carbon anode, and a carbon cathode; the anode fuel stream contains ascorbate and KOH, while the cathode oxidant stream contains either oxygen or H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉. Using 30% H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉, its maximum power density increases from 12 to 16 mW cm〈sup〉−2〈/sup〉 as the temperature increases from 25 to 60 °C. The second fuel cell is constructed with a Na〈sup〉+〈/sup〉 treated cation exchange membrane, a carbon anode, and a carbon cathode. With an alkaline anode fuel stream (ascorbate and KOH) combined with an acidic cathode oxidant stream (H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 and H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉) the maximum power density reaches 158 mW cm〈sup〉−2〈/sup〉 at 60 °C with 30% H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉. The performance of these fuel cells is quite promising, especially since the electrodes only consist of carbon black nanoparticles.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Yu Wu, Yigeng Huangfu, Rui Ma, Alexandre Ravey, Daniela Chrenko〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the fuel cell power applications, the output voltage and load power are variable which highly depends on the operating conditions. Thus, DC/DC power converters are usually utilized to obtain a constant voltage to match the subsequent power bus. Due to the non-linear characteristics of the fuel cell and load profiles, a stronger robustness design of power converters is required. In order to resolve the above issues, this paper designs a strong robust isolated flyback DC/DC converter for the fuel cell power applications. An all-digital controller based on high-order sliding mode (HSM) control is developed. The super-twisting algorithm of HSM is applied with a digital signal processor (DSP) TMS320F28035 that is used as the control chip. In the experiments, the designed digital HSM controller can achieve a fast convergence with a settling time of less than 0.1 ms and an overshoot of less than 0.1%. A typical incremental PI controller is also designed as the benchmark control method. The effectiveness of the proposed digital HSM controller is demonstrated through several different experiments conducted under large disturbances of load and input voltage.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318314009-fx1.jpg" width="402" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Ryan J. Milcarek, Hisashi Nakamura, Takuya Tezuka, Kaoru Maruta, Jeongmin Ahn〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Flame-assisted fuel cell (FFC) studies have been limited to lower fuel-rich equivalence ratios (∼1–1.7, due to the upper flammability limit and sooting limit) where only small concentrations of H〈sub〉2〈/sub〉 and CO can be generated in the exhaust. In this work, a non-catalytic microcombustion based FFC is proposed for direct use of hydrocarbons for power generation. The potential for high FFC performance (450 mW cm〈sup〉−2〈/sup〉 power density and 50% fuel utilization) in propane/air microcombustion exhaust is demonstrated. The micro flow reactor is investigated as a fuel reformer for equivalence ratios from 1 to 5.5. One significant result is that soot formation in the micro flow reactor is not observed at equivalence ratios from 1 to 5.5 and maximum wall temperatures ranging from 750 to 900 °C. Soot formation is observed at higher wall temperatures of 950 °C and 1000 °C and equivalence ratios above 2.5. H〈sub〉2〈/sub〉 and CO concentrations in the exhaust are found to have a strong temperature dependence that varies with the maximum wall temperature and the local flame temperature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Jiajia Cui, Junkai Wang, Xiongwen Zhang, Guojun Li, Kai Wu, Yonghong Cheng, Jun Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Protonic ceramic fuel cells offer the potential for environmentally sustainable and cost-effective electric power generation. However, the power outputs of protonic ceramic fuel cells are far from the requirements due to the lack of active cathodes. In this work, porous thin sheets Ca〈sub〉x〈/sub〉Y〈sub〉1-x〈/sub〉Fe〈sub〉0.5〈/sub〉Co〈sub〉0.5〈/sub〉O〈sub〉3-〈/sub〉〈sub〉δ〈/sub〉 (〈em〉x〈/em〉 = 0.1, 0.3 and 0.5) are synthesized by a modified pechini method and investigated as cathode materials for protonic ceramic fuel cells. Ca〈sub〉x〈/sub〉Y〈sub〉1-x〈/sub〉Fe〈sub〉0.5〈/sub〉Co〈sub〉0.5〈/sub〉O〈sub〉3-〈/sub〉〈sub〉δ〈/sub〉 show high electrical conductivities and excellent chemical compatibility with Ba(Zr〈sub〉0.1〈/sub〉Ce〈sub〉0.7〈/sub〉Y〈sub〉0.2〈/sub〉)O〈sub〉3〈/sub〉 electrolyte. The maximum electrical conductivity of Ca〈sub〉0.3〈/sub〉Y〈sub〉0.7〈/sub〉Fe〈sub〉0.5〈/sub〉Co〈sub〉0.5〈/sub〉O〈sub〉3-〈/sub〉〈sub〉δ〈/sub〉 reaches 202 S cm〈sup〉−1〈/sup〉 in air at 750 °C. The detailed mechanism for oxygen reduction reaction reveals that the rate-limiting step of oxygen reduction reaction is transformed from charge transfer to O〈sub〉2〈/sub〉 adsorption-dissociation with temperature rising or Ca doping. The composite cathode Ca〈sub〉0.3〈/sub〉Y〈sub〉0.7〈/sub〉Fe〈sub〉0.5〈/sub〉Co〈sub〉0.5〈/sub〉O〈sub〉3-〈/sub〉〈sub〉δ〈/sub〉-Ba(Zr〈sub〉0.1〈/sub〉Ce〈sub〉0.7〈/sub〉Y〈sub〉0.2〈/sub〉)O〈sub〉3〈/sub〉 presents a relatively low polarization resistance of 0.07 Ω cm〈sup〉2〈/sup〉 at 750 °C in air. The power density of the anode-supported cell of NiO〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉 Ba(Zr〈sub〉0.1〈/sub〉Ce〈sub〉0.7〈/sub〉Y〈sub〉0.2〈/sub〉)O〈sub〉3〈/sub〉∣Ba(Zr〈sub〉0.1〈/sub〉Ce〈sub〉0.7〈/sub〉Y〈sub〉0.2〈/sub〉)O〈sub〉3〈/sub〉∣Ca〈sub〉0.3〈/sub〉Y〈sub〉0.7〈/sub〉Fe〈sub〉0.5〈/sub〉Co〈sub〉0.5〈/sub〉O〈sub〉3-〈/sub〉δ-Ba(Zr〈sub〉0.1〈/sub〉Ce〈sub〉0.7〈/sub〉Y〈sub〉0.2〈/sub〉)O〈sub〉3〈/sub〉 is 798 mW cm〈sup〉−2〈/sup〉 as the electrolyte thickness is about 150 μm. The prepared Ca〈sub〉x〈/sub〉Y〈sub〉1-x〈/sub〉Fe〈sub〉0.5〈/sub〉Co〈sub〉0.5〈/sub〉O〈sub〉3-〈/sub〉〈sub〉δ〈/sub〉 oxides are promising candidates as high-performance cathodes for protonic ceramic fuel cells.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313818-fx1.jpg" width="441" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): H. Moussaoui, R.K. Sharma, J. Debayle, Y. Gavet, G. Delette, J. Laurencin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The performances of Solid Oxide Cells (SOCs) are controlled by key microstructural properties such as the density of Triple Phase Boundary lengths (TPBl) and the interfacial specific surface areas (〈em〉S〈/em〉〈sub〉〈em〉i/j〈/em〉〈/sub〉). These electrode properties are dependent on basic morphological parameters defined by the phase volume fractions and the Particle Size Distributions (PSD) of the percolated solid phases. The understanding of these relationships is of central importance for designing an optimum electrode microstructure. In this study, semi-analytical expressions for the density of TPBl and the interfacial specific surface areas are investigated. For this purpose, a large number of synthetic microstructures are generated by using validated models based on the sphere packing and the truncated Gaussian random field methods. The coefficients of the parametric equations for both investigated properties (TPBl density and 〈em〉S〈/em〉〈sub〉〈em〉i/j〈/em〉〈/sub〉) are fitted on the large database generated. The predictions of the microstructural correlations are in good agreement with the parameters directly computed on 3D reconstructions of typical LSCF-CGO and Ni-YSZ electrodes, thereby validating their reliability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Chi Him A. Tsang, Kwun Nam Hui, K.S. Hui〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Highly active and stable electrocatalysts for ethanol oxidation reaction (EOR) are very important for applications in fuel cells. Even though huge efforts have been devoted to enhancing their catalytic activity, preparation of open-structure electrodes by a green and binder-free method remains a challenge. It is obvious in graphene aerogel (GA) based materials due to the destruction of the original GA structure by traditional fabrication methods. In this report, Pd〈sub〉1〈/sub〉Pt〈sub〉x〈/sub〉 alloy NPs/GA/nickel foam electrodes (Pd〈sub〉1〈/sub〉Pt〈sub〉x〈/sub〉/GA/NF) were prepared by a green, simple and binder-free one-step method. The results show that the mean particle size and distribution of Pd〈sub〉1〈/sub〉Pt〈sub〉x〈/sub〉 alloy NPs and the Pd〈sub〉1〈/sub〉Pt〈sub〉x〈/sub〉 loading ratios (at%; x = 2.92, 1.31, 1.03) on the electrodes are strongly dependent on the initial concentration of PtCl〈sub〉6〈/sub〉〈sup〉2−〈/sup〉 ions in the synthesis solution. The Pd〈sub〉1〈/sub〉Pt〈sub〉x〈/sub〉/GA/NF electrodes were evaluated for EOR. The Pd〈sub〉1〈/sub〉Pt〈sub〉1.03〈/sub〉/GA/NF electrode exhibits high activity and stability in EOR under a long operation (1000 cycles), which are attributed to the synergistic effect of the bimetallic Pd〈sub〉1〈/sub〉Pt〈sub〉x〈/sub〉 alloy NPs on the electrode. This study introduced a binder-free, current-collector-free electrode preparation method which may provide new opportunities to develop high-performance electrodes for energy generation and storage technologies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Shidong Song, Limei Yu, Yanli Ruan, Jian Sun, Butian Chen, Wu Xu, Ji-Guang Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Irreversible parasitic reactions and the resulting accumulation of insulating side products are main barriers for practical application of rechargeable lithium–oxygen (Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈sub〉2〈/sub〉) batteries. Therefore, it is critical to develop multifunctional oxygen electrodes suitable for oxygen reduction reaction, oxygen evolution reaction, and decomposition of side reaction products. Here we report the application of ultrafine ruthenium on boron carbide (Ru/B〈sub〉4〈/sub〉C) with highly efficient multifunctional activities as carbon-free oxygen electrodes for Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈sub〉2〈/sub〉 batteries. Li〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 and LiOH can be completely decomposed by Ru/B〈sub〉4〈/sub〉C at 4.0 V and 4.1 V, respectively, within the stability window of the electrolyte. A Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈sub〉2〈/sub〉 battery using the Ru/B〈sub〉4〈/sub〉C oxygen electrode achieves low overpotentials for Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈sub〉2〈/sub〉 reactions, and excellent cycling performance under the capacities of 300 and 500 mAh g〈sup〉−1〈/sup〉〈sub〉Ru/B4C〈/sub〉. In-situ gas chromatography analysis reveals that O〈sub〉2〈/sub〉 is the major gas product during charging. Only a negligible amount of CO〈sub〉2〈/sub〉 is observed in the first charging process. Therefore, Ru/B〈sub〉4〈/sub〉C can be a very promising oxygen-electrode material for Li〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈sub〉2〈/sub〉 batteries and Li–air batteries operated in ambient air.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313673-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 413〈/p〉 〈p〉Author(s): Ke Pan, Feng Zou, Marcello Canova, Yu Zhu, Jung-Hyun Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Silicon monoxide (SiO), similar to its more common counterpart silicon (Si), is considered as an attracting anode material for advanced Li-ion batteries (LiBs) due to its high theoretical capacity. However, many electrochemical properties of SiO have not been explored as much as those of Si. In this study, we report fundamental properties of SiO as an anode material, which offer promising LiB performances superior to pure Si anodes. The Li-ion diffusion in SiO was found to be consistently faster than that in Si, as evidenced by galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS). As a result, SiO anodes can deliver much improved fast charging/discharging capability compared with pure Si anodes, which indicates that SiO is a better candidate for high-power cell applications. The volume expansion rate of SiO particles was determined to be ∼118% by using scanning electron microscopy (SEM)-based particle size distribution (PSD) analysis, which is less than half of that of Si particles (c.a. 280%). Meanwhile, the open circuit potential (OCP) of SiO was found to be very close to Si, except near the end of delithiation state. These results provide fundamental information on SiO for its future applications as the next generation LiB anodes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Jian Xu, Jian-Bo Liu, Bai-Xin Liu, Bing Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pb-free halide double perovskites (HDPs) are proposed as potential candidates for various optoelectronic applications to replace the mainstream hybrid organic-inorganic halide perovskites, 〈em〉e.g.〈/em〉, CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉. While it is known that ion diffusion is a critical problem to affect the structural and electronic stability of CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉, the mechanism of ion diffusions in HDPs is still unclear and highly desired to be revealed. In this study, taking Cs〈sub〉2〈/sub〉AgInX〈sub〉6〈/sub〉 (X = Cl, Br) HDPs as prototypes, for the first time we suggest that the fast ion diffusion of the dominant defects may play an important role in the performance stability of HDPs. Importantly, we find that the Ag〈sub〉i〈/sub〉〈sup〉+〈/sup〉 diffusion in a multi-ion concerted fashion has a much faster diffusion rate, compared to the V〈sub〉Ag〈/sub〉〈sup〉−〈/sup〉 and V〈sub〉X〈/sub〉〈sup〉+〈/sup〉 diffusion in a single-ion fashion. It is revealed that HDPs exhibit quite different diffusion properties from CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉. Furthermore, we demonstrate that the diffusion rate of Ag〈sub〉i〈/sub〉〈sup〉+〈/sup〉 in HDPs can be effectively suppressed by applying an epitaxial strain, which opens a promising way to enhance the performance stability of perovskite materials for various device applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313661-fx1.jpg" width="274" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Jun Tang, Xiongwei Zhong, Haiqiao Li, Yan Li, Feng Pan, Baomin Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report an ultrafast in-situ laser reduction process of graphene oxides (GO) in LiFePO〈sub〉4〈/sub〉 electrodes, where the selective laser reduction of GO sheets is conducted after coating LiFePO〈sub〉4〈/sub〉 on current collector. This novel process technique avoids the solvophobicity and agglomeration problems of graphene in 1-methyl-2-pyrrolidinone (NMP) or other solvents for the electrode material slurry preparation because of GO's solvophilicity in various solvents. Under the optimized laser reduction condition, a hierarchical structure of graphene conductive network is formed without wrapping the LiFePO〈sub〉4〈/sub〉 surface, which can greatly improve the rate capability and cycle performance. The battery capacity remains 84.5% after 1000 cycles and 72.9% when the charge/discharge current density increases from 0.5C to 20C. The method developed in this work is also applicable for other material systems to selectively reduce GO for performance enhancement.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313600-fx1.jpg" width="263" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Shihui Yu, Chunmei Zhang, Muying Wu, Helei Dong, Lingxia Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ultra-high energy storage performance of lead-free ferroelectric materials has been achieved at room temperature by heterostructure composite based on environment-friendly BaSn〈sub〉0.15〈/sub〉Ti〈sub〉0.85〈/sub〉O〈sub〉3〈/sub〉 and Ba〈sub〉0.6〈/sub〉Sr〈sub〉0.4〈/sub〉TiO〈sub〉3〈/sub〉 thin films. The dielectric constant and loss tangent of BaSn〈sub〉0.15〈/sub〉Ti〈sub〉0.85〈/sub〉O〈sub〉3〈/sub〉 layers grown on the Ba〈sub〉0.6〈/sub〉Sr〈sub〉0.4〈/sub〉TiO〈sub〉3〈/sub〉 layers respectively are calculated as 402 and 0.0137 at 100 kHz. The interfacial layer between BaSn〈sub〉0.15〈/sub〉Ti〈sub〉0.85〈/sub〉O〈sub〉3〈/sub〉 and Ba〈sub〉0.6〈/sub〉Sr〈sub〉0.4〈/sub〉TiO〈sub〉3〈/sub〉 layers can improve the dielectric constant and reduce the loss tangent of heterostructures. The electrical breakdown strength can be significantly enhanced by the interfacial layer, and the influence mechanism is proposed. Ultra-high energy storage density as high as 43.28 J/cm〈sup〉3〈/sup〉, is obtained at a sustained high bias electric field of 2.37 MV/cm with a power density of 6.47 MW/cm〈sup〉3〈/sup〉 and an efficiency of 84.91% in the BaSn〈sub〉0.15〈/sub〉Ti〈sub〉0.85〈/sub〉O〈sub〉3〈/sub〉/Ba〈sub〉0.6〈/sub〉Sr〈sub〉0.4〈/sub〉TiO〈sub〉3〈/sub〉 heterostructure thin films.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Yuying Zhu, Chenghao Huang, Chao Li, Meiqiang Fan, Kangying Shu, Hai Chao Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electroactive materials with high electrochemical activity, good rate capability and excellent cycling stability are urgently needed for hybrid supercapacitors, but achieving those performances at the same time is still a big challenge. Here, α phase nickel−cobalt−manganese hydroxide (NiCoMn−OH) with a flower-like structure is synthesized and used as the battery materials for hybrid supercapacitor. The NiCoMn−OH exhibits strong synergetic electrochemistry between the transition metals, which contributes better charge storage performances. The NiCoMn−OH shows a specific capacity of 757 C g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉 and retains 369 C g〈sup〉−1〈/sup〉 at very high specific current of 50 A g〈sup〉−1〈/sup〉, which are both much higher than the corresponding bimetal and nomometal hydroxides. Therefore, both high electrochemical activity and rate capability have been achieved. The α phase NiCoMn−OH also exhibits a long-term cycling stability because the specific role of Co, maintaining 100% of the specific capacity after 1200 cycles. The hybrid supercapacitor based on NiCoMn−OH also shows high specific capacity of 219 C g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉, high rate performance of 53% capacity retention when the specific current increases 25 times and ultralong cycling stability of 83% capacity retention after 12,000 cycles.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313351-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 412〈/p〉 〈p〉Author(s): Fei Li, Dong Wang, Qiongzhen Liu, Bo Wang, Weibing Zhong, Mufang Li, Ke Liu, Zhentan Lu, Haiqing Jiang, Qinghua Zhao, Chuanxi Xiong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study attempts to prompt the formation of microorganism films on flexible textile-based anodes and enhances the performance of living microorganisms by introducing magnetic properties to the anodes. A magnetic and electrically conductive anode for a microbial fuel cell is designed and fabricated by encapsulating uniformly dispersed SrFe〈sub〉12〈/sub〉O〈sub〉19〈/sub〉 nanoparticles into the poly(vinyl alcohol-〈em〉co〈/em〉-ethylene) (PVA-〈em〉co〈/em〉-PE) nanofibers and forming a three-dimensional (3D) polypyrrole (PPy) network on the surface of flexible composite nanofiber based fabric. A dual-chamber MFC equipped with the magnetized anode shows a maximum power density of 3317 mW m〈sup〉−2〈/sup〉, which is significantly larger than that of the non-magnetized anode (2471 mW m〈sup〉−2〈/sup〉). This study demonstrates that the hard-magnetic anode providing an inherent magnetic field can greatly promote bio-electrochemical reaction rates of 〈em〉E. coli〈/em〉, and decrease the anode charge transfer resistance in a MFC system.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318313454-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 404〈/p〉 〈p〉Author(s): N.J. Steffy, S. Vinod Selvaganesh, Madan Kumar L, A.K. Sahu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study deals with a novel diagnostic tool for fuel and water management problems by analyzing the harmonics on an operating polymer electrolyte membrane fuel cell. In this method, a low frequency signal is applied to the fuel cell and the total harmonic distortion contained in the resulting signal is observed under different conditions. The total harmonic distortion is used to monitor and identify the conditions online such as anode drying, anode flooding, hydrogen starvation and cathode flooding prevailing in the cell. This is done by identifying a set of indicator frequencies correspond to the aforementioned critical conditions. Through empirical studies, it is shown that frequency responses lead to a high total harmonic distortion value indicating critical conditions and provide an accurate diagnostic method to detect an even slightly degraded state. These results successfully demonstrate the promise of the proposed method in overcoming performance losses by efficient online monitoring of fuel cells. The relation between the health of the fuel cell and the variations in the harmonics present in the studied signal is characterized and utilized for the diagnostic studies of polymer electrolyte membrane fuel cell.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 405〈/p〉 〈p〉Author(s): Yanzhi Sun, Shicheng Guo, Wei Li, Junqing Pan, Carlos Fernandez, Raja Arumugam Senthil, Xueliang Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metal Organic Frameworks or related carbon materials are the ideal materials for supercapacitors due to their high surface area and unique porous structure. Here, we propose a new green and recyclable synthesis method of porous carbon. Aluminum hydroxide (Al(OH)〈sub〉3〈/sub〉) and trimesic acid (BTC) are employed as raw materials to obtain aluminium trimesic (denoted as Al-BTC) via their covalent reaction. Then, the porous carbon is obtained through carbonization and dissolving process to remove the aluminum oxide (Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉). Al(OH)〈sub〉3〈/sub〉 is recovered by the Bayer method for the next batch. The SEM images show that the porous carbon has rugby-like morphology with the same of 400 nm wide and 1000 nm long which indicates the porous carbon with c/a ratio of 2.5 providing the largest specific volume surface area. The sample offers 306.4 F g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉, and it can retain 72.2% even at the current density of 50 A g〈sup〉−1〈/sup〉. In addition, the porous carbon provides excellent durability of 50,000 cycles at 50 A g〈sup〉−1〈/sup〉 with only 5.05% decline of capacitance. Moreover, the porous carbon has an ultrafast charge acceptance, and only 4.4 s is required for one single process, which is promising for application in electric vehicles.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311261-fx1.jpg" width="269" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 405〈/p〉 〈p〉Author(s): Andrea Baricci, Matteo Bonanomi, Haoran Yu, Laure Guetaz, Radenka Maric, Andrea Casalegno〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Improving the durability of polymer electrolyte membrane fuel cells with low platinum loading is a crucial step in the development of next generation electric vehicles. In this work a simplified model of nanoparticle growth is spatially solved across the catalyst layer and combined with a PEMFC model to analyze the heterogeneity of degradation that is induced by accelerated stress test for electrocatalyst durability, which mimics the degradation due to load cycling. The model is calibrated and later validated by analyzing experimental data collected on cathode catalyst layers with 0.1 mg cm〈sup〉−2〈/sup〉 platinum loading and average particle size ranging from 2 nm to 5 nm. Non-uniform degradation is observed in the catalyst layer consequently to the formation of a platinum depleted region next to the membrane, which, according to the model, results from diffusion and precipitation of dissolved platinum into the membrane. Performance of catalyst layers with gradient structure is simulated to get insight into the degradation of non-uniform catalyst layers and results are compared to experimental data. It is concluded that gradient catalyst layers mitigate performance degradation because evolve towards more uniform distribution of active surface and improve transport loss due to low-roughness factor and Ohm loss in the catalyst layer.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 404〈/p〉 〈p〉Author(s): Xinfang Jin, Surinder Singh, Atul Verma, Brandon Ohara, Anthony Ku, Kevin Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present computational study investigates the effects of pressure and flow patterns on the electrochemical performance of a repeating unit in the anode-support SOFC stack using a reduced order model previously developed. A unique feature of the present study is that the charge, heat, and mass transport affecting the cell performance has been coupled with the temperature field. The focus of this study is to simulate how the flow patterns and operating pressure in conjunction with temperature field coupling impact the electrochemical performance and chemical reactions within syngas-fueled SOFCs. The simulation results show that the benefits of pressure on power performance do not increase linearly, but with a tapering of performance at higher pressure ranges. This indicates that an intermediate pressure operation may offer a balance between increased performance but higher cost in pressurized systems. The counter-flow design yields a narrower temperature gradient than the co-flow design across the stack, thus leading to a better overall performance. The simulations also find that pressurization significantly promotes the CO direct electro-oxidation and reverse water gas shift reaction simultaneously, thus resulting in higher power density.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 405〈/p〉 〈p〉Author(s): Yao Wang, Xueling Lei, Yanxiang Zhang, Fanglin Chen, Tong Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, 〈em〉in-situ〈/em〉 fabricated nano-socketed Fe-Ni particles structured Sr〈sub〉2〈/sub〉Fe〈sub〉1.5〈/sub〉Mo〈sub〉0.5〈/sub〉O〈sub〉6-δ〈/sub〉 (SFM) electrodes are proposed to simultaneously combine good electrochemical properties of Ni-based materials and good stabilities of SFM-based materials. Preliminary studies on the Ellingham diagram and density functional theory offer certain theoretical basis for realizing the feasibility to extract Fe-Ni alloy from parent Sr〈sub〉2〈/sub〉Fe〈sub〉1.3〈/sub〉Ni〈sub〉0.2〈/sub〉Mo〈sub〉0.5〈/sub〉O〈sub〉6-δ〈/sub〉 in the viewpoint of thermodynamic and minimum energy principle. Experimental results according to X-ray diffraction, scanning electron microscopy-elements mapping, high resolution transmission electron microscopy measurements show that a large amount of uniformly dispersed Fe-Ni nano-catalysts are elegantly exsolved from the perovskite oxide parent. Electrical conductivity relaxation results indicate that surface exchange coefficient of SFM-based material is enhanced from 0.5 × 10〈sup〉−3〈/sup〉 to 1.7 × 10〈sup〉−3〈/sup〉 cms〈sup〉−1〈/sup〉 by the 〈em〉in-situ〈/em〉 growth of Fe-Ni alloy at 800 °C. The 〈em〉in-situ〈/em〉 fabricated Fe-Ni@SFM combined with Ce〈sub〉0.8〈/sub〉Sm〈sub〉0.2〈/sub〉O〈sub〉1.9〈/sub〉 (SDC) composite electrodes perform a considerably high electrolysis current density of 1257 mA cm〈sup〉−2〈/sup〉 at 1.3 V, 850 °C and polarization resistance of 0.20 Ωcm〈sup〉2〈/sup〉 at open circuit voltage and 850 °C. Distribution relaxation of time analysis of impedance spectra shows that the gas conversion process is the rate-limiting step in the Fe-Ni@SFM-SDC hydrogen electrode for steam electrolysis.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311157-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 405〈/p〉 〈p〉Author(s): J. Sun, L. Zeng, H.R. Jiang, C.Y.H. Chao, T.S. Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrospinning has been employed to fabricate carbonaceous materials with larger surface areas for vanadium redox flow batteries. However, the woven carbon nanofibers prepared with conventional electrospinning methods are plagued by the low porosity and poor permeability, thereby causing a significant mass-transport resistance during the operation of batteries. To tackle this problem, we report a novel method by self-assembling porous carbon fibers into large bundles to form electrodes. This electrode is fabricated by electrospinning polyacrylonitrile and polystyrene binary solutions. Instead of forming single fibers, the individual fibers are self-assembled into fiber bundles by properly managing the viscosity of the precursor solution. The formation of large fiber bundles significantly enlarges the pore size while retaining large specific surface areas. The single cell with the as-prepared electrodes achieves an energy efficiency of 87.7% at a current density of 100 mA cm〈sup〉−2〈/sup〉, which is 15.2% higher than that of the single cell with conventional electrospinning electrodes. The energy efficiency still maintains over 80% at 200 mA cm〈sup〉−2〈/sup〉. More importantly, the discharge capacity and electrolyte utilization are nearly doubled. All these results demonstrate that this electrode preparation method is effective to improve the mass transport properties of traditional electrospun electrodes in vanadium redox flow batteries.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 404〈/p〉 〈p〉Author(s): Jiahe Xu, Feng Zheng, Cuiping Xi, Yi Yu, Lai Chen, Weiguang Yang, Pengfei Hu, Qiang Zhen, Sajid Bashir〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report a heterojunction composite of V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanobelt arrays/TiO〈sub〉2〈/sub〉 nanoflake arrays grown directly on nickel foam. The morphology evolution and growth mechanism of TiO〈sub〉2〈/sub〉 nanoflake arrays on V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanobelt arrays are investigated in detail. The heterojunction composite nano-arrays have a large specific capacitance of 587 F g〈sup〉−1〈/sup〉 at a current density of 0.5 A g〈sup〉−1〈/sup〉, a high coulombic efficiency (〉92%), an excellent cycle stability (92%) after 5000 cycles and a low charge transfer resistance of 2.6 Ω. When the heterojunction composite nano-arrays are assembled into symmetric supercapacitor, the device shows a high energy density of 100.8 W h kg〈sup〉−1〈/sup〉 at a power density of 399 W kg〈sup〉−1〈/sup〉. The high supercapacitive performance is attributed to their direct growth on conductive current collector and the synergistic effect of V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 and TiO〈sub〉2〈/sub〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318310875-fx1.jpg" width="362" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 404〈/p〉 〈p〉Author(s): Zelong He, Lan Zhang, Shuai He, Na Ai, Kongfa Chen, Yanqun Shao, San Ping Jiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reversing the direction of polarization current is essential for reversible solid oxide cells technologies, but its effect on cobaltite based perovskite oxygen electrodes is largely unknown. Herein, we report the operating stability and microstructure at the electrode/electrolyte interface of La〈sub〉0.57〈/sub〉Sr〈sub〉0.38〈/sub〉Co〈sub〉0.18〈/sub〉Fe〈sub〉0.72〈/sub〉Nb〈sub〉0.1〈/sub〉O〈sub〉3-δ〈/sub〉 (LSCFN) oxygen electrodes assembled on barrier-layer-free Y〈sub〉2〈/sub〉O〈sub〉3〈/sub〉〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉ZrO〈sub〉2〈/sub〉 electrolyte under cyclic anodic/cathodic polarization mode at 0.5 A cm〈sup〉−2〈/sup〉 and 750 °C. During the cyclic polarization, the electrocatalytic activity of LSCFN electrode is drastically deteriorated in cathodic mode, but the performance loss is largely recoverable in anodic mode. This is due to the fact that the surface segregation of Sr and accumulation at the electrode/electrolyte interface by cathodic polarization can be remarkably mitigated by anodic polarization. The time period in each cycle plays a key role in determining the accumulation of Sr species at the electrode/electrolyte interface. A full cell operating in a time period of 12 h fuel-cell/12 h electrolysis is reversible for a duration of 240 h, in contrast to the performance degradation in a shorter time period of 4 h fuel cell/4 h electrolysis. The present study sheds lights on applying cobaltite based perovskite oxygen electrodes on barrier-layer-free YSZ electrolyte for reliable solid oxide cells.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 405〈/p〉 〈p〉Author(s): Jingyi Wu, Hongxia Zeng, Qingxuan Shi, Xiongwei Li, Qing Xia, Zhigang Xue, Yunsheng Ye, Xiaolin Xie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Uncontrollable lithium (Li) dendrite growth has hampered the application of lithium metal batteries (LMBs). Herein, a novel plastic crystal composite polymer electrolyte (nh-CPE) consisting of multifunctional two-dimensional (2D) molybdenum disulfide (MoS〈sub〉2〈/sub〉) and ion-conducting one-dimensional (1D) surfactant oxidized cellulose nanocrystal (OCNC) is developed to overcome this challenge. The nh-CPE possesses good Li-dendrite-suppressing ability, which is attributed to the well-designed three-dimensional (3D) ion conducting network constructed by homogeneously dispersed MoS〈sub〉2〈/sub〉 and OCNC. This structure facilitates Li-ion conductivity and enables uniform Li deposition on the anode. Moreover, the impermeable MoS〈sub〉2〈/sub〉 nano-flakes with excellent mechanical strength serve as physical barriers to hold the electrolyte-electrode interface stability and consequently block Li dendrite growth and enhance fire retardancy. When applied in LMB, the nh-CPE exhibits excellent cycle performance and rate capability, with 90% capacity retention after 200 cycles at 0.5 C and 60 °C, and a discharge capacity of 128 mAh g〈sup〉−1〈/sup〉 at 1 C. Notably, owing to high room-temperature ionic conductivity (0.8 mS cm〈sup〉−1〈/sup〉), the cell with nh-CPE cycled at room temperature delivers an initial discharge capacity of 144 mAh g〈sup〉−1〈/sup〉. The outstanding performance and simple process offer great opportunity to promote Li-dendrite-suppressing LMBs for practical application.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311224-fx1.jpg" width="291" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 405〈/p〉 〈p〉Author(s): Hongyu Liang, Yongfeng Bu, Fuping Pan, Junyan Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Transforming carbon-containing wastes into useful porous carbon materials is highly desired. The strategy can not only relieve environmental pollution but obtain porous carbon electrodes for energy storage devices. Herein we report an efficient method to transform the ozone-depleting gas of Freon (CCl〈sub〉3〈/sub〉F) into 3D graphene (3DG) frameworks for supercapacitor electrode materials. The 3DG possesses self-supporting interconnected meso- and macropore channels supported by the multilayer graphene frameworks, which can be well kept in actual 3DG electrodes. This characteristic, together with high conductivity, enables 3DG supercapacitors to present high rate performance through the effective synergy between ion and electron transports, thus achieving the high capacitance retention of 76.1% (156 F g〈sup〉−1〈/sup〉 at 100 A g〈sup〉−1〈/sup〉) relative to the original capacitance (205 F g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉), as well as high energy density retention (42.3% at 100 A g〈sup〉−1〈/sup〉). The capacitance retention is much higher than that of typical reduced graphene oxide, and comparable to those of the reported state-of-the-art carbon-based materials. This study provides new strategy to dispose carbon-rich environmental pollutants for useful porous carbon electrode materials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775318311091-fx1.jpg" width="498" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 404〈/p〉 〈p〉Author(s): Sandip Maurya, Phong Thanh Nguyen, Yu Seung Kim, Qinjun Kang, Rangachary Mukundan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Addition of flow fields to carbon paper electrodes in a vanadium redox flow battery (VRFB) can improve the peak power density through uniform distribution of electrolyte in the electrodes. However, it is unclear whether flow fields have a similar effect with graphite felt electrodes, as VRFBs with felt electrodes reported in literature show a large anomaly in obtained power density. In this work, we evaluate three flow fields; viz. serpentine, interdigitated and conventional (without flow pattern) type with felt electrodes and compare their performance with a serpentine flow field using carbon paper electrodes under identical experimental conditions. The conventional flow field provides highest energy efficiency (75%) followed by serpentine (64%) and interdigitated (55%) at 0.2 A cm〈sup〉−2〈/sup〉 attributable to the deteriorating electrolyte distribution in the electrodes. Computation fluid dynamic simulations confirm the experimental finding of worsening electrolyte distribution (conventional 〈 serpentine 〈 interdigitated). A power density of 0.51 W cm〈sup〉−2〈/sup〉 at 60 mL min〈sup〉−1〈/sup〉 flow rate is obtained for serpentine and conventional flow fields with felt electrodes; comparable to the highest power density reported in literature for high performing zero-gap flow field architecture. This paper gives comprehensive insights on flow fields for VRFBs that can be extended to other flow batteries.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 407〈/p〉 〈p〉Author(s): Haiying Che, Xinrong Yang, Hong Wang, Xiao-Zhen Liao, Sheng S. Zhang, Chunsheng Wang, Zi-Feng Ma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sodium-ion pouch cells with up to 1000 cycles are presented by using a NaNi〈sub〉1/3〈/sub〉Fe〈sub〉1/3〈/sub〉Mn〈sub〉1/3〈/sub〉O〈sub〉2〈/sub〉 cathode, a hard carbon anode, and a functional electrolyte. The functional electrolyte is composed of 1 M NaPF〈sub〉6〈/sub〉 dissolved in a 1:1 (v/v) mixed solvent of propylene carbonate (PC) and ethyl methyl carbonate (EMC) with 3–4 wt% of two or three additives, including fluoroethylene carbonate (FEC), prop-1-ene-1,3-sultone (PST), and 1,3,2-Dioxathiolane-2,2-dioxide (DTD). It is shown that the capacity retentions of the cells increase to 84.4% and 92.2% after 1000 cycles for electrolytes containing FEC-PST bi-additive and FEC-PST-DTD tri-additive, respectively, as compared with that containing FEC single additive. Using X-ray photoelectron spectroscopy, inductively coupled plasma optical, and transmission electron microscopy, post-mortem analyses on the surface of the cycled electrodes indicate that PST and DTD are beneficial to the anode by forming an organic compound rich solid electrolyte interphase (SEI), and to the cathode by forming a dense and thick cathode electrolyte interphase (CEI) that consequently prevents transition metal ions from dissolving into electrolyte.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 30 September 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources〈/p〉 〈p〉Author(s): Youngkwon Kim, Yun Young Choi, Nari Yun, Mingyu Yang, Yonghee Jeon, Ki Jae Kim, Jung-Il Choi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An activity gradient carbon felt (AGCF) electrode is prepared by a simple thermal oxidation method, which is composed of both a low activity electrode near the inlet side and a high activity electrode near the outlet side. The vanadium redox flow battery (VRFB) full cell with AGCF electrodes shows higher discharge capacity (18.7 Ah L〈sup〉−1〈/sup〉) and coulomb efficiency (93.6%) than non-gradient carbon felt electrodes (14.3 Ah L〈sup〉−1〈/sup〉, 88.4%) at a current density of 80 mA cm〈sup〉−2〈/sup〉. From the computational analysis, the AGCF electrodes exhibit reduced overpotential results as well as improved uniform activity at low reactant concentration condition during charging and discharging at the current density. These results suggest that the AGCF electrode is an effective electrode design for high-performance VRFB featuring high energy density by improving electrolyte utilization as well as high roundtrip efficiency by improving energy efficiency.〈/p〉〈/div〉 〈/div〉