ALBERT

Description: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Xingyun Luo, Xiucai Sun, Yanlu Li, Fapeng Yu, Li Sun, Xiufeng Cheng, Xian Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Charge neutrality is vital to improve the performance of electronic devices based on epitaxial graphene grown on SiC substrates. First-principle calculations are applied to predict the charge-neutral epitaxial graphene by intercalating B〈sub〉3〈/sub〉C〈sub〉5〈/sub〉 layer between the SiC substrate and a buffer carbon layer. The electronic structure of graphene is found to be modulated by adjusting the B:C ratio of a series of B〈sub〉x〈/sub〉C〈sub〉y〈/sub〉 intercalation layers. The buffer layer is eliminated and the intrinsic 〈em〉n〈/em〉-doping of as-grown graphene is avoided by preventing the charge transfer between graphene and the SiC substrate. The calculated surface energy of the B〈sub〉3〈/sub〉C〈sub〉5〈/sub〉-intercalated structure shows considerable stability as compared to the other intercalated structures over a wide range of temperatures and pressures under B-rich conditions. These findings will promote the practical application of B〈sub〉3〈/sub〉C〈sub〉5〈/sub〉-intercalated epitaxial graphene on SiC(0001) as a core element of microelectronic devices at high temperature, or pressure sensors at variable pressure conditions.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301147-egi103CPH9XSLQ.jpg" width="346" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Laleh Abbasi, Majid Arvand, Seyyed Ebrahim Moosavifard〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Engineering of nanostructured electrodes for enhancing their electrochemical performance is a critical issue to further development in energy storage systems. In the present study, we have developed a facile template-free method to engineer 3D hierarchical ravine-like electrode based on MnCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 nanosheet arrays as an efficient material for high-performance electrochemical capacitors. The physico-chemical characteristics of ravine-like structure of MnCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 nanosheets are investigated by different techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The as-prepared MnCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 electrode exhibits an ultrahigh specific capacity of 834 C g〈sup〉−1〈/sup〉 (231 mAh g〈sup〉−1〈/sup〉) at the current density of 1 A g〈sup〉−1〈/sup〉, excellent rate capability and good cycle performance. Thiospinel nature of the MnCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 electrode and its ravine-like nanosheet structure with effective spatial confinement for the electrolyte ions and charge transportation are responsible for this remarkable performance. Furthermore, the assembled MnCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉//AC asymmetric device shows the maximum energy density of 57 W h kg〈sup〉−1〈/sup〉 and the highest power density of 20.8 kW kg〈sup〉−1〈/sup〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A template-free method has been developed to engineer 3D ravine-like interconnected MnCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 nanosheet arrays as a positive electrode material for asymmetric electrochemical capacitors.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301135-fx1.jpg" width="370" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Rui Zhang, Ning Wang, Chunsheng Shi, Enzuo Liu, Chunnian He, Naiqin Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Li metal is the essential anode material for high-energy-density batteries due to its low electrochemical potential and high specific capacity (3860 mAh g〈sup〉−1〈/sup〉). Unfortunately, the uneven plating/stripping of Li metal causes uncontrolled Li dendrites growth, which induces low cycling efficiency and safety concerns. Herein, we report a 3D graphene framework with continuous duct-like structure (3DCG) as a stable host for Li metal anode. The lithium plating behavior on 3DCG was investigated through 〈em〉ex-situ〈/em〉 and 〈em〉in-situ〈/em〉 techniques. The duct-like graphene provides the pathway accelerating the Li〈sup〉+〈/sup〉 diffusion and promotes homogeneous metallic Li deposition throughout the 3D framework. The continuously porous structure of 3DCG electrode provides a space for the metallic Li deposition and could effectually adjust the volume expansion during cycles. As a result, the 3DCG electrode exhibits a high average Coulombic efficiency of 98.7% over 1000 h, an extremely high capacity (up to 20 mAh cm〈sup〉−2〈/sup〉, 3236 mAh g〈sup〉−1〈/sup〉), and a stable Li plating/stripping performance even at a high current density of 10 mA cm〈sup〉−2〈/sup〉. Meanwhile, the full batteries coupled with sulfur cathodes show excellent cycling stability. This work presents the approach to realize the uniform Li deposition throughout the 3D framework and long-lifespan lithium metal batteries.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300841-fx1.jpg" width="491" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Li Xiang, Fan Xia, Wanlin Jin, Xiangwen Zeng, Fang Liu, Xuelei Liang, Youfan Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electronic devices with configurability to providing multiple functions are of great interests for their superior adaptability to the ever-changing and multifarious application scenarios. Here, we report flexible integrated circuits (ICs) possessing configurable functions constructed with dual-material gate (DMG) devices based on carbon nanotube thin films, which can serve as either transistors or diodes, on a 2-μm-thick parylene substrate. When configured as a transistor, the DMG device has great advantages over the normal-gated (NG) devices regarding the current on/off ratio (〈em〉I〈/em〉〈sub〉on〈/sub〉/〈em〉I〈/em〉〈sub〉off〈/sub〉), the subthreshold swing (〈em〉SS〈/em〉) and the drain-induced barrier lowering (DIBL) due to the regulated energy band distribution in channel area. When operating as a diode, a typical DMG device demonstrates a sufficient rectification ratio of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mn〉8〈/mn〉〈mo linebreak="goodbreak" linebreakstyle="after"〉×〈/mo〉〈msup〉〈mrow〉〈mn〉10〈/mn〉〈/mrow〉〈mrow〉〈mn〉4〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 and a diode-on-current of over 26 μA. Scalable manufacturing of DMG devices was also demonstrated with great uniformity both in diode and transistor configurations. Finally, multifunctional integrated circuits, which can dynamically switch their function from rectifier to follower or from OR gate to voltage adder by changing controlling signals, were constructed. The functional-configurability, together with scalable manufacturing and the realization on ultrathin flexible substrates, will open up great opportunity for the future environmentally-adaptive system in the field of flexible electronics.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301032-fx1.jpg" width="419" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Xianrong Huang, Renfu Li, Lijian Zeng, Xueling Li, Zhaojun Xi, Kun Wang, Yichao Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Excellent multifunctional polymeric nanocomposite cannot be achieved without good dispersion and well protection of nanofillers, for which a highly efficient, cost-effective and environmental benign nanofiller treatment approach is demanded. Herein, we report that soy protein isolate (SPI), an extracted protein from soybean, is applied as a highly performed bio-surfactant to treat carbon nanotubes (CNTs), resulting in nanocomposite with tremendously improved dispersion, electrical and mechanical properties. TEM, UV–vis and dynamic light scattering (DLS) and real-time optical microscopic characterizations show that, compared with a conventional surfactant, sodium dodecylsulfate (SDS), SPI more effectively and efficiently functionalize CNTs with less agglomerates and more stable particle size distribution. The electrical conductivity of the SPI-CNTs/epoxy increased by 6 orders of magnitude at 0.5 wt% vs pure epoxy, which is 4 orders higher than the pristine CNTs/epoxy and even 1 order higher than that of the SDS treated counterpart. The tensile modulus, strength and fracture toughness of the SPI-CNTs/epoxy increased by 27%, 24% and 32% at 1.0 wt% loading of CNTs, respectively, which is 20%, 26% and 18% higher than the pristine CNTs/epoxy and 10%, 23% and 21% higher than the SDS-CNTs/epoxy. The in-situ tensile test accompanied by digital image correlation technique (DIC) shows that cracks are effectively arrested by the SPI-CNTs while SDS-CNTs cannot. These results establish a solid foundation for the application of SPI in the polymeric nanocomposite fields.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300762-fx1.jpg" width="400" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Yun Chen, Chun-Sheng Guo, Wang Gao, Qing Jiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Revealing the distinction between rolling and sliding at the nanoscale is crucial for understanding the nanoscale tribology. To address this issue, we studied the rolling and sliding of single-walled carbon nanotubes (CNTs) on graphene using density functional theory augmented with many-body dispersion (MBD) forces method. We find that the motion of CNTs on graphene is changed from sliding to rolling with increasing the CNT radius, in which Pauli repulsion dominates rolling and MBD interactions dictate sliding. In addition, armchair CNTs always generate larger barriers than zigzag CNTs with similar radius regardless of rolling and sliding. These phenomena originate from the decay and fluctuations of charge density with respect to the distance between CNTs and graphene. Based on the potential corrugation of CNT motion on graphene, we also extend a model to capture the viscous friction of rolling and sliding with the experimental accuracy, providing a reasonable mechanistic picture for understanding the available experimental findings.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301044-fx1.jpg" width="275" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Pengcheng Chen, Jordan N. Metz, Anthony S. Mennito, Shamel Merchant, Stuart E. Smith, Michael Siskin, Steven P. Rucker, David C. Dankworth, J. Douglas Kushnerick, Nan Yao, Yunlong Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Petroleum pitch has played a significant role in carbon science as a key abundant resource for polycyclic aromatic hydrocarbons in making various higher value carbon materials. Despite many detailed studies using advanced characterization techniques over 50 years, the exact nature of the molecular structures of petroleum M − 50 pitch molecules remains unclear, due to the molecular diversity and their low solubility of this material. In this study, we applied real-space single molecule imaging non-contact atomic force microscopy to obtain exact structures of individual molecules, and compared the results from other characterization techniques to validate some of the previously hypothesized average structures. We identified a diverse slate of largely catacondensed polycyclic aromatic hydrocarbons with short alkyl chains, such as methyl and methylene groups. Furthermore, both single core and multi-core structures have been observed, in contrast to previous assertions that only one type would be present. The presence of these structures enables a mechanistic rationalization for their formation and allows potential mechanisms for the thermal conversion of pitch into larger bonding networks to be postulated.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300695-fx1.jpg" width="409" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): J.H. Chu, L.B. Tong, M. Wen, Z.H. Jiang, D.N. Zou, S.F. Liu, H.J. Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The poor corrosion/wear resistance of Mg alloy seriously limits its industrial application. Graphene-based anti-corrosion coatings show the excellent imperviousness, but they can provide the additional cathodic sites for Mg alloys, which accelerates the galvanic corrosion behaviors near the interfaces. A novel design of cerium-based intermediate layer (Ce(Ⅳ)) is reported in this study, which exhibits a synergistic effect of hydrogen/ionic bond on the graphene oxide (GO)/polyvinyl alcohol (PVA) biomimetic coating. It overcomes the problems of galvanic corrosion and low interfacial adhesion between Mg substrate and hybrid coating through a prominent barrier effect. Furthermore, the GO/PVA coating with “bricks and mortar” structure effectively blocks the permeation of electrolyte due to the reduced porosity and enhanced densification. The corrosion rate of Ce(Ⅳ)/GO/PVA coating is 11 and 19 times lower than bare Mg alloy and single GO/PVA film, respectively. The wear rate of GO/PVA and Ce(Ⅳ)/GO/PVA samples is decreased by 98.8% and 97.6%, which is ascribed to the high hardness and lubrication of GO sheets. Moreover, the relatively interlayer slipping between GO sheets can lubricate the sliding process. Compared with GO/PVA, the slightly decreased wear resistance of Ce(Ⅳ)/GO/PVA coating is resulted from the enhanced shear force.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301056-fx1.jpg" width="467" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Takafumi Ishii, Jun-ichi Ozaki〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A deuterium-labeled temperature-programmed desorption (TPD) technique was developed to accurately characterize functional groups on the surface of carbon-based materials. After the protic hydrogen of the functional groups on activated carbons was substituted by deuterium, TPD analysis revealed the desorption of deuterium compounds (D〈sub〉2〈/sub〉O, DHO, D〈sub〉2〈/sub〉, DH). The functional groups were estimated from the predicted desorption mechanisms of these deuterium compounds, which can be distinguished according to the functional groups and their surrounding chemical structures. Thus, this technique provides information on not only the type of functional groups but also the extensive chemical structure around them. The phenolic group, ether, and edge hydrogen formed on the activated carbons were separately quantified, and the functional groups were further classified into 12 types by the nearby chemical structures. Comparison with IR spectra indicated that the deuterium-labeled TPD gave qualitatively reasonable results. This technique is useful for obtaining a deeper understanding of the surface chemical structure of carbon-based materials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300865-fx1.jpg" width="253" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Qinglun Che, Hao Li, Ligang Zhang, Fuyan Zhao, Guitao Li, Yufeng Guo, Jianjun Zhang, Ga Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Multi-walled carbon nanotubes (MWCNTs), and MWCNTs/zirconia nanoparticles (nano-ZrO〈sub〉2〈/sub〉) hybrids were compounded into a formulated non-asbestos brake material of phenolic binder, respectively. It is demonstrated that even low-loading above nanofillers switching virtually the original brake material to an extremely wear-resistant self-lubricating material. More interestingly, the addition of MWCNTs/nano-ZrO〈sub〉2〈/sub〉 hybrids leads to formation of a double-deck tribofilm yielding extraordinarily low friction and wear. First-principles calculations demonstrate that O atoms from air ambience break carbon-carbon backbones of CNTs, facilitating them to convert into graphitic nanograins. Our work provides direct evidence that graphitic nanograins and nano-ZrO〈sub〉2〈/sub〉 are digested within the beneath layer of the tribofilm, whilst chelation of polymer chains radicals with nano-ZrO〈sub〉2〈/sub〉 expedites formation of a carbon-based lubricous top layer. The present work puts forward a new strategy for endowing numerous mechanical motion systems with a robust self-lubrication characteristic via tuning tribofilms’ nanostructures.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Growth of a double-deck tribofilm yielding ultra-low friction and wear.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000862232030110X-fx1.jpg" width="267" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 26 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Laís Helena Sousa Vieira, Carla Manuela Sganzerla Sabino, Francisco Holanda Soares Júnior, Janaina Sobreira Rocha, Manuela Oliveira Castro, Rafael Silva Alencar, Luelc Souza da Costa, Bartolomeu Cruz Viana, Amauri Jardim de Paula, João Maria Soares, Antônio Gomes de Souza Filho, Larissa Otubo, Pierre Basílio Almeida Fechine, Anupama Ghosh, Odair Pastor Ferreira〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Magnetic carbonaceous nanocomposites (MCN) were prepared by hydrothermal carbonization (HTC) of a carbohydrate in the presence of Fe〈sup〉3+〈/sup〉, followed by thermal treatment with KOH for simultaneous activation and magnetization. The precursor formed (IOCN) in the HTC process contained iron oxide nanoparticles encapsulated in the hydrochar matrix. The thermochemical parameters of the activation (temperature and IOCN/KOH mass-ratio) were varied to achieve an increase of the specific surface area along with formation of magnetic phases in MCN compared to IOCN. Activation temperature was found to be responsible for the structural and morphological properties of the MCNs whereas the IOCN/KOH mass-ratio controlled the porosity. The magnetic properties of the MCNs originated from the formation of Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 and Fe〈sup〉0〈/sup〉 phases, encapsulated in the carbonaceous material. They were tested for adsorption of methylene blue (MB) dye, followed by magnetic separation. The MCN, produced in the best conditions, showed a specific surface area of 766 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉, magnetization of 8 emu g〈sup〉−1〈/sup〉 and a MB adsorption capacity of 570 mg g〈sup〉−1〈/sup〉. Detailed kinetic and isotherm studies of MB adsorption were also performed. The methodology of simultaneous activation and magnetization to generate MCNs, presented here, could be extended to obtain new multifunctional carbon-based nanocomposite adsorbent starting from different biomasses.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301081-fx1.jpg" width="357" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Mengjue Cao, Yi Feng, Rongrong Tian, Qian Chen, Jinghang Chen, Mingmin Jia, Jianfeng Yao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Highly flexible carbon foam with double-layer structure and hierarchical pores is synthesized based on Co-ZIF-L supported on carbonized melamine sponge (MS). Due to the special leaf-like structure of Co-ZIF-L, the uniform in-situ growth of ZIF-L onto carbonized MS makes the three-dimensional carbon wires dendriform-like, which after carbonization and KOH activation, sufficient micro- and mesopores are created resulting from Co-ZIF-L particles and gaps among them. Such hierarchical pore structure significantly improves the specific capacities (238 F/g at 1 A/g compared to that of 92 F/g for carbonized pristine MS). Moreover, due to the excellent mechanical properties inheriting from MS, the obtained sample can be used directly as a flexible electrode and remains high electrochemical performance under different bending states (the capacitance remains 99% and 96.1% respectively when bent at 90° and 180°). When using such foam as all-solid-state supercapacitors, it shows high specific capacity (149 F/g at 5 mV/s), high stability in high operation voltage window (0–1.8 V) and excellent flexibility, which makes such material a potential candidate for high-performance supercapacitors in modern portable and wearable devices.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301123-fx1.jpg" width="497" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 26 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Yang Zhang, Wenjie Liu, Zheng Wang, Yong-Miao Shen, Wenchang Wang, Zhidong Chen, Juan Xu, Jianyu Cao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Aqueous hybrid flow batteries (AHFBs) are considered as a cost-effective large-scale energy storage system for renewable energy applications. Herein, using π-π stacking directed self-assembly, we report an electrochemically active composite material comprising planar π-conjugated molecules (tetrapyridophenazine, TPPHZ) and two-dimensional (2-D) graphene nanoplatelets for high-performance anodes of AHFBs. The TPPHZ/graphene composite shows highly negative redox potential, rapid electrochemical reaction kinetics and excellent electronic conductivity in aqueous alkaline electrolyte. Using TPPHZ/graphene composite as the anode and ferrocyanide salt as the catholyte, respectively, the AHFB cell yields a cell voltage of 1.3 V and realizes a specific power of 29.4 W g〈sup〉−1〈/sup〉 (at 100% state of charge) and an average energy efficiency of ∼89.3% (at a current density of 5 A g〈sup〉−1〈/sup〉). Furthermore, this AHFB cell shows extremely stable cycling performance, with over 81.4% capacity retention (99.9938% per cycle) after 3000 consecutive cycles.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301111-fx1.jpg" width="295" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Minglong Yang, Ye Yuan, Ying Li, Xianxian Sun, Shasha Wang, Lei Liang, Yuanhao Ning, Jianjun Li, Weilong Yin, Renchao Che, Yibin Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lightweight, low-cost electromagnetic (EM) wave absorption materials are in urgent need, as EM interference pollution is increasingly serious. Carbon material as EM absorber has attracted ever increasing attention. However, their absorption property is still limited. Herein, we propose a very simple strategy to prepare hierarchical carbon fiber coated with Co/C nano-dodecahedron particles where CNTs were anchored (HCF@CZ-CNTs), using cotton and metal-organic-framework (MOF) as raw materials. One of MOF, ZIF-67 particles were 〈em〉in-situ〈/em〉 grown onto the surface of cotton fibers. Lightweight HCF@CZ-CNTs samples were obtained by direct carbonization, the apparent density of which is only 0.0198 g/cm〈sup〉3〈/sup〉. The minimum reflection loss (RL〈sub〉min〈/sub〉) of hierarchical HCF@CZ-CNTs was dramatically enhanced to −53.5 dB at 7.8 GHz, compared with pure carbonized cotton fiber (RL〈sub〉min〈/sub〉 = −18.9 dB at 16 GHz). Meanwhile the effectively absorption bandwidth was also remarkably enlarged to 8.02 GHz. The excellent EM wave absorption performance is attributed to the micro-to-nano hierarchical hollow fibrous structure, as well as the synergetic effect of polarization relaxation and magnetic loss. These results illuminate a low-cost and sustainable strategy to prepare ultra-lightweight microwave absorbers with excellent EM wave absorbing ability utilizing biomass precursor and MOF.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A hierarchical carbon fiber coated with dodecahedral Co/C nanoparticles and villus-like CNTs was fabricated using cotton and ZIF-67(HCF@CZ-CNTs), which shows ultra-low apparent density (0.0198 g/cm〈sup〉3〈/sup〉), minimum −53.5 dB microwave reflection loss at 7.8 GHz as well as broad effective absorption bandwidth of 8.02 GHz.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300804-fx1.jpg" width="270" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Qianyue Cui, Cunguang Chen, Chengwei Yu, Tianxing Lu, Haiming Long, Shuhao Yan, Alex A. Volinsky, Junjie Hao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Graphite flakes (GFs) in the GF/Cu composites generally fail to exert the advantage of the negative coefficient of thermal expansion (CTE) on account of the weak interfacial bonding between GFs and Cu. In this work, a rivet-joint strategy is adopted to surmount the dilemma. By introducing submicron Mo particles into the Cu matrix through the chemical synthesis process, various GF/Cu composites with the improved alignment of GFs via the method of tape-casting and hot-pressing sintering have been prepared. Due to the combined effects of Mo particle strengthened Cu and the rivet-joint interfacial architecture deriving from the in-situ synthesized Mo〈sub〉〈em〉x〈/em〉〈/sub〉C, optimized thermal/mechanical properties of GF/Cu–Mo composites have been achieved. The 50 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mi〉v〈/mi〉〈mi〉o〈/mi〉〈mi〉l〈/mi〉〈mtext〉%〈/mtext〉〈/mrow〉〈/math〉 GF/Cu composite with 1 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈mi〉w〈/mi〉〈mi〉t〈/mi〉〈mtext〉%〈/mtext〉〈/mrow〉〈/math〉 Mo shows the in-plane thermal conductivity of 598 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈mrow〉〈mi〉W〈/mi〉〈mo linebreak="goodbreak" linebreakstyle="after"〉⋅〈/mo〉〈msup〉〈mrow〉〈mi〉m〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈/mrow〉〈/msup〉〈mo linebreak="goodbreak" linebreakstyle="after"〉⋅〈/mo〉〈msup〉〈mrow〉〈mi〉K〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 and the through-plane CTE of −2.92〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈mrow〉〈mo linebreak="goodbreak" linebreakstyle="after"〉×〈/mo〉〈msup〉〈mrow〉〈mn〉10〈/mn〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉6〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si5.svg"〉〈mrow〉〈msup〉〈mrow〉〈mi〉K〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 (25–100 〈sup〉∘〈/sup〉C). Simultaneously, the bending strength is 40〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si6.svg"〉〈mrow〉〈mtext〉%〈/mtext〉〈/mrow〉〈/math〉 higher than the 50 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mi〉v〈/mi〉〈mi〉o〈/mi〉〈mi〉l〈/mi〉〈mtext〉%〈/mtext〉〈/mrow〉〈/math〉 GF/Cu composite. This strategy could promote the development of composites with improved combined structural and functional properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Fulai Zhao, Yu Wang, Xin Zhang, Xuejing Liang, Fei Zhang, Ling Wang, Yu Li, Yiyu Feng, Wei Feng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Germanene, as a cousin of graphene, has shared increasing attention in recent years. There have been abundant theoretical and experimental reports on the synthesis and physicochemical properties of germanene, but few experiments have investigated the energy storage properties. Herein, this study reports the electrochemical properties of GeCH〈sub〉3〈/sub〉, a methyl terminated germanene, as anode materials for lithium-ion batteries (LIBs). First, few-layer GeCH〈sub〉3〈/sub〉 nanosheets were prepared by liquid-phase exfoliation. Then to further explore the electrochemical lithium storage potential of GeCH〈sub〉3〈/sub〉 nanosheets, sandwiched GeCH〈sub〉3〈/sub〉/rGO nanocomposites were prepared by adding rGO as a conductive agent and stabilizer through a simple ultrasonic wet dispersion mixing process. The resulting nanocomposite exhibited a remaining capacity of 1058 mAh g〈sup〉−1〈/sup〉 after 100 cycles at 0.2 A g〈sup〉−1〈/sup〉, indicating that GeCH〈sub〉3〈/sub〉 nanocomposite is a promising high energy density anode material. This encouraging result may shed light on the application of germanene in LIBs.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300798-fx1.jpg" width="419" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Shukai Ding, Wei Cheng, Gaohui Du, Qingmei Su, Linjuan Guo, Xiaojuan Chen, Shuai Zhang, Lin Shang, Xiaodong Hao, Bingshe Xu, Christophe A. Serra〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Application of the graphene-based composites in practice was hampered due to the lack of the controllable synthesis strategy. To solve the problem, we envisaged the organic nanodroplets as a nano-reaction environment to obtain the organic nanoframes by photo-polymerization, then to directly graphitize for the graphene-based materials. In such strategy, two-dimensional laminar matrix of graphene nanosheets (2DLM〈sub〉G〈/sub〉) was obtained with millimeter-scale surface, which rendered the matrix high electron conductivity. Thanks to the confinement effect of the nanodroplets, the composited materials were homogeneously dispersed in the organic nanoframes. Then, the organic nanoframes converted directly to 2DLM〈sub〉G〈/sub〉-based composites after calcination. In this paper, the transformation from organic nanoframes to 2DLM〈sub〉G〈/sub〉 has been revealed in detail by comprehensive analyses from SEM, XRD and XPS. To demonstrate the versatility of 2DLM〈sub〉G〈/sub〉, the superiority in lithium ion battery has been indicated by the high specific capacity (565 mA h g〈sup〉−1〈/sup〉), high cycling performance after 500 cycles and the 100% retention capacity in rate measurement. For the synthesis of the composites, Sn nanoparticles and γ-Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanoparticles were distributed in 2DLM〈sub〉G〈/sub〉 without the aggregation with high loading. The proposed organic molecule confinement reaction strategy was expected to point out a promising direction for the preparation of graphene-based materials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300828-fx1.jpg" width="326" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Yansheng Liu, Huayu Feng, Feng Luo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a study of quantitative analysis of the defects in chemical vapor deposition (CVD) grown graphene through plasmon-enhanced Raman scattering has been performed. By designing and fabricating three-dimensional hybrid Au nano-particles/single-layer-graphene/Au nano-holes (Au NPs/SLG/Au NHs) structures, the defects induced Raman scattering signals of SLG have been extremely enhanced. The light-graphene interaction between graphene and plasmonic nanostructures heightened the cross-section of the Raman scattering resulting in enhancing Raman signals. In the SERS spectra of graphene, the D band and D′ band which associated with defects-induced double resonance (DR) Raman scattering processes have been clearly observed. A general and empirical formula has been applied to quantify graphene defects nano-crystallite (La) through the relation between the ratio of I〈sub〉D〈/sub〉/I〈sub〉G〈/sub〉 and E〈sub〉L〈/sub〉〈sup〉4〈/sup〉. Additionally, an empirical formula for quantifying the defects based on the relation between I〈sub〉D’〈/sub〉/I〈sub〉G〈/sub〉 and E〈sub〉L〈/sub〉〈sup〉4〈/sup〉 was proposed. Besides, the Au NPs/SLG/Au NHs as a SERS substrate has been applied in detecting the fluorescein molecular under low concentration, and it exhibited good SERS performance.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The defects-induced signals of graphene are enhanced by SERS, and the empirical formulas are proposed to quantify graphene defects nano-crystallite.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300701-fx1.jpg" width="263" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Zejun Zhang, Jinli Qin, Huailing Diao, Shasha Huang, Jin Yin, Hui Zhang, Yongxin Duan, Jianming Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Janus graphene oxide (GO) usually refers to a unique two-dimensional material with asymmetric surface chemistries on opposite faces of the sheets. Herein, we propose a facile and efficient method to fabricate Janus-like GO (JGO) with a novel asymmetric structure along the faces of the sheets. Unlike the traditional post-synthesis of double-faced Janus GO based on pre-prepared GO, the novel JGO with a randomly distributed asymmetric oxidation structure along the sheet face can be achieved by a simple ultrasonic treatment on partially oxidized graphene. The asymmetric oxidation structure along the sheet face of our Janus GO was confirmed by confocal micro-Raman imaging and analysis of height profiles by atomic force microscopy. Due to the asymmetric oxidation structure, the as-prepared JGO has amphiphilic characteristics, with hydrophilicity on one side of the sheet and hydrophobicity on the other side, leading to an eyelash-like liquid crystal alignment at the oil/water interface. The perpendicular alignment rather than the parallel orientation behavior of GO liquid crystals at the oil/water interface further confirms the asymmetric structure of our JGO along the face graphene sheets. The simple approach and a new class of JGO proposed herein provide a new insight into understanding the asymmetric chemistry of graphene.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The facile preparation of Janus GO nanosheets with asymmetric surface chemistries and eyelash-like liquid crystal alignment at the oil/water interface.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300853-fx1.jpg" width="334" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Wenxiang Xu, Peng Lan, Yaqing Jiang, Dong Lei, Haixia Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interphase configurations affect conductive properties of carbon fibrous composites (CFCs), specifically the percolation of interphase triggers the dramatic change of conductive properties. It has been a key but unresolved issue how to capture the percolation of soft interphase interacted by anisotropic-shaped carbon fibers and its quantitative effect on the conductivity of CFCs. This work proposes a theoretical framework for the accurate predictions of the excluded volume and percolation threshold of soft interphase and the effective conductivity of CFCs. This framework contains three theoretical models: (1) a coupling scheme between the second virial coefficient theory and Monte Carlo simulations for determining the excluded volumes; (2) an excluded-volume-based percolation model for obtaining the percolation threshold of soft interphase; (3) a continuum percolation-based micromechanical model (CPMM) for predicting the effective conductivity of CFCs with spherocylindrical carbon fibers of high volume fraction and their surrounding interphase percolation. Comparison against numerical and experimental data validates that the theoretical framework can well predict these properties of CFCs. This framework can be regarded as a general scheme that is readily applicable to other core-shell networks. Furthermore, we use the framework to probe various factors effects on the percolation threshold of interphase and electrical conductivity of CFCs.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300907-egi10K9QS9T5GL.jpg" width="372" alt="Image 10995" title="Image 10995"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Nathan Schaefer, Ramon Garcia-Cortadella, Andrea Bonaccini Calia, Nikolaos Mavredakis, Xavi Illa, Eduard Masvidal-Codina, Jose de la Cruz, Elena del Corro, Laura Rodríguez, Elisabet Prats-Alfonso, Jessica Bousquet, Javier Martínez-Aguilar, Antonio P. Pérez-Marín, Clement Hébert, Rosa Villa, David Jiménez, Anton Guimerà-Brunet, Jose A. Garrido〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Poor metal contact interfaces are one of the main limitations preventing unhampered access to the full potential of two-dimensional materials in electronics. Here we present graphene solution-gated field-effect-transistors (gSGFETs) with strongly improved linearity, homogeneity and sensitivity for small sensor sizes, resulting from ultraviolet ozone (UVO) contact treatment. The contribution of channel and contact region to the total device conductivity and flicker noise is explored experimentally and explained with a theoretical model. Finally, in-vitro recordings of flexible microelectrocorticography (μ-ECoG) probes were performed to validate the superior sensitivity of the UVO-treated gSGFET to brain-like activity. These results connote an important step towards the fabrication of high-density gSGFET μ-ECoG arrays with state-of-the-art sensitivity and homogeneity, thus demonstrating the potential of this technology as a versatile platform for the new generation of neural interfaces.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300737-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Jun Sun, Shyam Kanta Sinha, Amir Khammari, Matthieu Picher, Mauricio Terrones, Florian Banhart〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is shown that graphitic shells encapsulating metal nanoparticles facilitate the amorphization of metals and stabilize the amorphous phase against recrystallization. In an 〈em〉in-situ〈/em〉 electron microscopy experiment, where the objects are exposed to laser pulses during their observation, the amorphization of iron and cobalt nanocrystals in graphitic shells is demonstrated. The infrared nanosecond pulses lead to fast melting of the metal which then dissolves carbon atoms from the shell. Fast cooling of the liquid solution after the pulse results in the solidification of an amorphous metal-carbon phase. The amorphous phase is metastable and can be recrystallized by repeated laser pulses or slow thermal annealing. The recrystallization needs heterogeneous nucleation but is unfavorable at the metal-graphite interface and so stabilizes the amorphous phase against recrystallization. The analysis of the experiments explains the formation mechanisms of an amorphous metal-carbon phase as a metastable solution of carbon in a transition metal and shows how that the encapsulation by a graphitic shell can be a route towards the stabilization of otherwise unfavorable amorphous metal or metal-carbon phases.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300749-fx1.jpg" width="400" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Youngho Eom, Sung Min Son, Yea Eun Kim, Jung-Eun Lee, Sang-Ha Hwang, Han Gi Chae〈/p〉

Description: 〈p〉Publication date: Available online 25 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Yun Wang, Dong Lu, Fei Wang, Dongxing Zhang, Jing Zhong, Binghao Liang, Xuchun Gui, Li Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bottom-up and top-down are two different strategies to prepare nano-materials and their assemblies, each with their own pro-and-cons. Here, we demonstrate a combined approach in preparing large area uniform carbon nanotube (CNT) thin films within minutes, several orders of magnitude faster than conventional methods. This strategy takes full advantage of the unique micro-structure of CNT sponges, synthesized by a bottom-up process and composed of physically entangled CNTs with uniform size and spatial distribution. Such a 3D network structure allows us to firstly transfer certain amount of structured CNTs from the sponge onto a Scotch tape. Through a second-step stamping process, which is essentially a top-down process, transparent and conductive (TCF) CNT films with controlled micro-structures are produced on viscous substrates. Bonding strength between the stamped CNT network and elastomer substrate can be adjusted to optimize the physical properties including the transparency and sheet resistance of the CNT thin films. Upon stretching, the device exhibits high piezoresistive responsiveness; combining high sensitivity, low hysteresis and large working strain range. The proposed methodology had been extended to fabricate micro-electrodes on patterned elastomers with same effectiveness. These experimental results highlight the high efficiency, low-cost and versatility of this approach in preparing TCF electrodes with different sizes and shapes.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320301093-egi10GRCHCF0HM.jpg" width="175" alt="Image 100" title="Image 100"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 25 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Zhimin Chen, Xiaofeng Wang, Beichen Xue, Wei Li, Zhiyao Ding, Xiaomin Yang, Jieshan Qiu, Zichen Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rice husk-based hierarchical porous carbon (RHPC) has great promising applications in supercapacitors. Herein we systematically examined the formation mechanism of hierarchical porous structure of RHPC, tried to work out the intrinsic relationship of pore structure and the electrochemical performance. A method for separation of components in rice husk is proposed. It has been found that the pore structure in RHPC is closely related to different components in rice husk, and can be tuned by carbonization, desiliconization, and activation, shedding a light on the formation mechanism of the hierarchical porous structure in RHPC. The electrochemical performance of RHPC and the porous carbons made from three rice husk components has been correlated to their porous structure. The micropores function to provide a large number of adsorption sites for electrolyte ions, leading to high specific capacitance, while the mesopores coupled with the macropores function to provide fast transport channels for electrolyte ions, which play the key role for the excellent rate capability of RHPC. The stable skeleton structure with good conductivity ensures the superior cycling stability of RHPC.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Via a detailed component separation method, the pore source, the formation mechanism of hierarchical porous structure, and the structure-performance relationship of RHPC are determined.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000862232030107X-fx1.jpg" width="280" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 26 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Mohammad Ramezanzadeh, Bahram Ramezanzadeh, Mohammad Mahdavian, Ghasem Bahlakeh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a novel corrosion protective coating with an excellent barrier, and superior active anti-corrosion characteristics was constructed through a one-pot synthesis method of zeolitic imidazolate framework-8 (ZIF-8) on the graphene oxide sheets. Experimental results proved the successfully synthesize of GO@ZIF-8 particles with a 79% improvement of the specific surface area compared with the neat GO. A corrosion inhibition efficiency of about 79% was recorded for the steel sample immersed in the NaCl solution containing GO@ZIF-8 particles extract by the polarization test, proving the active inhibition properties of GO@ZIF-8 particles. The low-frequency impedance (|〈em〉Z〈/em〉|〈sub〉10 mHz〈/sub〉) values greater than 10〈sup〉10〈/sup〉 Ω cm〈sup〉2〈/sup〉 were recorded by EIS analysis for the GO@ZIF-8/epoxy coating at all immersion times, indicating the superior barrier anti-corrosion properties of this coating. The pull-off and cathodic delamination tests revealed about 73% and 60% improvements of the epoxy coating cathodic delamination resistance and wet adhesion strength, respectively, in the presence of GO@ZIF-8 particles in comparison with the neat epoxy sample. The EIS outcome revealed a 70% improvement in the corrosion resistance of the GO@ZIF-8 loaded epoxy composites with an artificial defect after 72 h immersion than the neat epoxy sample, indicating the good smart inhibition activity for this sample.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300890-fx1.jpg" width="287" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 25 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): An Hua, Yong Li, Desheng Pan, Jian Luan, Yu Wang, Jun He, Shufang Tang, Dianyu Geng, Song Ma, Wei Liu, Zhidong Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The hollow carbon nanowires with large number of surface defects and specific surface have been prepared by de-alloying Al〈sub〉4〈/sub〉C〈sub〉3〈/sub〉@C nanowires. Compared to the graphene-based or carbon-nanotube-based wave-absorbing composites reported previously, the hollow carbon nanowires achieve enhanced wideband microwave absorption due to enhanced impedance match and increased electric dipoles, which are related to the defects on the surface of the distinctive hollow structure. As a result, the complex dielectric and microwave absorption properties of the hollow carbon nanowires are significantly optimized in 2–18 GHz range. The composites filled with 50 wt% of hollow carbon nanowires in paraffin show a minimum reflection loss (RL) of −47.1 dB at 15.7 GHz with a thickness of 1.9 mm and 5.5 GHz (RL  〈  −10 dB) absorbing bandwidth with thickness of 2 mm, being one of the most competitive carbon-based absorbers. This study provides an effective way to improve the microwave performance of the hollow carbon nanowires by template method.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300889-fx1.jpg" width="282" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 25 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Lin Zhang, Zhuorui Song, Binxing Zhao, Ezekiel Villarreal, Heng Ban〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Energy transfer between gases and solid surfaces plays a vital role in many technologies. Thermal accommodation coefficient (TAC), which specifies the energy transferred between a surface composed of thermally-vibrating atoms and a colliding gas molecule, can be calculated by sampling the incident velocities of gas molecules by the Maxwell-Boltzmann (MB) distribution. However, the MB distribution describes gas behavior in free space rather than near a solid surface. In this work, we calculated the TAC between helium and graphite by a modified Maxwell-Boltzmann distribution accounting for the fast atom effect where gases of higher out-of-plane velocity have a larger chance of reaching the solid surface at the same period. A significant reduction in TAC is found by correcting the MB distribution with the modified-MB distribution, 32.7% for helium at 500 K and 10.74% at 300 K. Further analysis shows that the out-of-plane velocity component dominates the scattering process and energy transfer. This result underlines the importance and necessity to correct the MB distribution to incorporate the fast atom effect. Moreover, the lower and upper boundaries of the scattering events were depicted. These findings can provide a fundamental understanding of gas-surface energy transfer and guidelines for molecular dynamics simulations for TAC.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300658-fx1.jpg" width="244" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Dan Liu, Eunja Kim, Philippe F. Weck, David Tománek〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We use 〈em〉ab initio〈/em〉 spin-polarized density functional theory to study the magnetic order in a Kagomé-like 2D metamaterial consisting of pristine or substitutionally doped phenalenyl radicals polymerized into a nanoporous, graphene-like structure. In this and in a larger class of related structures, the constituent polyaromatic hydrocarbon molecules can be considered as quantum dots that may carry a net magnetic moment. The structure of this porous system and the coupling between the quantum dots may be changed significantly by applying moderate strain, thus allowing to control the magnetic order and the underlying electronic structure.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300609-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Dini Wang, Rui Dai, Xing Zhang, Lei Liu, Houlong Zhuang, Yongfeng Lu, Yan Wang, Yiliang Liao, Qiong Nian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanoholes on the basal plane of graphene can provide abundant mass transport channels and chemically active sites for enhancing the electrochemical performance. However, current thermal chemical etching processes to manufacture these nanoholes commonly suffer from insufficient process efficiency, scalability and controllability, due to the conventional bulk heating strategy lacks capability to promote the etching reactions. To address this issue, a novel process is developed using microwave irradiation to promote and control the chemical etching of graphene. In this process, the microwave can induce a selective heating of graphene in the liquid solution and then facilitate the etching reactions occurring on the graphene-etchant interface. Applying this strategy, a remarkable reduction of processing time from hour-scale to minute-scale compared to the conventional approaches have been achieved with the control of the population and area percentage of nanoholes on the graphene basal plane. DFT and MD simulations revealed that the formation of nanoholes originated from the cyclic etchant oxidation process occurring at the edge-sites atoms around pretreated vacancies on graphene basal plane. The obtained holey graphene oxide sheets exhibit excellent capacitive performance and electrochemical catalytic activity due to the improvements in the accessible surface area, ion diffusion, and heterogeneous charge transfer.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000862232030083X-fx1.jpg" width="336" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Song Tian, Lu Zhou, Zhongtian Liang, Yu Yang, Yanru Wang, Xinfa Qiang, Shilin Huang, Haojie Li, Shi Feng, Zhonghao Qian, Yangbo Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hafnium carbide nanowires (HfCnw) were in-situ grown in 2.5 D needle-punched carbon felts by a catalyst-assisted chemical vapor deposition method. Subsequently, the carbon felts were densified to obtain HfCnw reinforced carbon/carbon (HfCnw-C/C) composites via chemical vapor infiltration. Effects of HfCnw on electrical conductivity, electromagnetic shielding properties and oxidation resistance of C/C composites were investigated for the first time. The results show that the SE〈sub〉T〈/sub〉 of C/C composites with 1.75 wt. % HfCnw exceeds 40 dB in the whole frequency range of 8.2-12.4 GHz, implying more than 99.99% of the incident beam was shielded. Moreover, it is found that the relative magnitude relationship of the total shielding effectiveness of composites (SE〈sub〉T(S-2h)〈/sub〉 〉 SE〈sub〉T(S-3h)〈/sub〉 ˃ SE〈sub〉T(S-0h)〈/sub〉) is similar with the conductance (〈span〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300877-egi10CQ85RWFN4.jpg" width="7" alt="Image 1" title="Image 1"〉〈/span〉〈sub〉S-2h〈/sub〉 〉 〈span〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300877-egi10CQ85RWFN4.jpg" width="7" alt="Image 2" title="Image 2"〉〈/span〉〈sub〉S-3h〈/sub〉 〉 〈span〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300877-egi10CQ85RWFN4.jpg" width="7" alt="Image 3" title="Image 3"〉〈/span〉〈sub〉S-0h〈/sub〉), which indicates the conductance can effectively predict the relative magnitude of the SE〈sub〉T〈/sub〉. In addition, the analysis based on oxidation curves demonstrates that HfCnw significantly enhance the oxidation resistance of the composites even with a small amount of HfCnw. The high electromagnetic interference (EMI) shielding effectiveness coupled with relatively low density and good oxidation resistance of HfCnw-C/C composites make itself exhibit remarkable potential as lightweight and high-performance structural-functional integrated materials for future EMI shielding application.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300877-egi10BRRS75VVF.jpg" width="500" alt="Image 1075" title="Image 1075"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Diego L. Silva, João Luiz E. Campos, Thales F.D. Fernandes, Jeronimo N. Rocha, Lucas R.P. Machado, Eder M. Soares, Douglas R. Miquita, Hudson Miranda, Cassiano Rabelo, Omar P. Vilela Neto, Ado Jorio, Luiz Gustavo Cançado〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A metrological framework for statistical analysis of number of layers and stacking order in mass-produced graphene using Raman spectroscopy is presented. The method is based on two complementary protocols, denominated by 2D and G. The 2D–protocol is based on the parameterized principal component analysis of the two-phonon 2D band, and it measures interlayer coupling. A neural-network algorithm for spectral denoising was also developed to improve the outcome. The G–protocol explores the intensity of the bond-stretching G band, and provides information about the number of layers. The method is suitable for automated statistical analysis of heterogeneous graphene-based systems with relatively low computational cost, as shown here for graphene flakes prepared by the liquid-phase exfoliation of graphite.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300567-fx1.jpg" width="270" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 22 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Tomonori Ichikawa, Naohiro Shimizu, Kenji Ishikawa, Mineo Hiramatsu, Masaru Hori〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carbon nanowalls (CNWs) are vertically standing, interconnecting flake- or wall-like collections of graphene sheets. In the present work, this material was synthesized by applying precisely controlled high-voltage nanosecond pulses to a substrate using an inductor energy storage circuit in a radical-injection plasma-enhanced chemical vapor deposition system, employing a CH〈sub〉4〈/sub〉/H〈sub〉2〈/sub〉 plasma. The resulting interconnected networks had a low density of CNWs with large average wall-to-wall distances. During the application of short-period pulses, the entire substrate surface was uniformly activated, thus enhancing the adsorption of carbon precursors and preventing CNW nucleation. As a result, an amorphous carbon film covered the surface of the substrate and a low CNW density was obtained with average wall-to-wall distances greater than 700 nm. On the basis of these results, the growth mechanism of CNWs was modeled.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300713-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 22 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Nikita M. Kuznetsov, Sergey I. Belousov, Artem V. Bakirov, Sergei N. Chvalun, Roman A. Kamyshinsky, Alexey A. Mikhutkin, Alexander L. Vasiliev, Peter M. Tolstoy, Anton S. Mazur, Eugeny D. Eidelman, Elena B. Yudina, Alexander Ya Vul〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The paper describes the data on unusual rheological properties of detonation nanodiamonds (DND) hydrosols and presents the fractal model explaining such behavior. The hydrosols of DND with particles size of 4–5 nm and concentration range of 1.1–7.3 wt% with negative (〈em〉ζ〈/em〉 〈 0) and positive (〈em〉ζ〈/em〉 〉 0) electrokinetic potentials have been studied by rotational viscometry, small-angle X-ray scattering, nuclear magnetic resonance and Cryo Electron Tomography. Remarkable hysteresis of viscosity and thixotropic effect demonstrate the sol-gel transition at very low concentrations of the DND: 4–5 wt% for 〈em〉ζ〈/em〉 〉 0 and 5–6 wt% for 〈em〉ζ〈/em〉 〈 0. The transition is accompanied by increase of loss (viscosity) modulus by two orders of magnitude and the storage (elasticity) modulus started to be detected also. The experimental results have been explained in the frame of percolation theory based on the network formation due to faceted DND particles interactions.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300610-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Bingfei Nan, Kun Wu, Zhencai Qu, Luqi Xiao, Changan Xu, Jun Shi, Mangeng Lu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we developed a multifunctional thermal management nanocomposite paper (NPG) consisting of cationic poly (diallyldimethylammonium chloride) (PDDA)-functionalized graphene oxide (PG) and nanodiamond (ND). Due to the functionalized reduction of graphene oxide (GO) by PDDA as well as electrostatic interactions between the positively charged PG and negatively charged ND, a three-dimensional (3D) hybrid NPG paper constructed by two-dimensional (2D) PG layers and zero-dimensional (0D) ND particles was successfully prepared via a vacuum-assisted self-assembly strategy. The resulting NPG papers were characterized by various techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS). In this analogous 3D “panel-bead” structure, adjacent PG nanosheets and ND particles are bridged through electrostatic interactions, which strengthens the interface connection and reduces phonon scatterings, resulting in an effective phonon transport pathway. Thus, a superior in-plane thermal conductivity of 16.653W m〈sup〉−1〈/sup〉K〈sup〉−1〈/sup〉 was obtained at the mass ratio of GO:ND = 3:1 (NPG3), which is about 80 times higher than that of traditional pure polymers. In addition, the peak heat release rate (PHRR) of NPG3 paper was only 99.16 W g〈sup〉−1〈/sup〉 at 439.2 °C while that of GO was 438.4 W g〈sup〉−1〈/sup〉 at 210.9 °C, indicating that NPG paper possesses excellent flame retardancy. More interestingly, although the NPG3 paper has excellent insulation (electrical resistivity reaches up to 2.647 × 10〈sup〉11〈/sup〉 Ω cm), the ultrafast flame alarm response was found within about 1s after the paper exposed to the flame. This design idea provides an alternative approach for preparing multifunctional thermal management nanocomposites in the future.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300634-fx1.jpg" width="253" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Youngho Eom, Sung Min Son, Yea Eun Kim, Jung-Eun Lee, Sang-Ha Hwang, Han Gi Chae〈/p〉

Description: 〈p〉Publication date: Available online 22 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Jinjin Li, Jianfeng Li, Xinchun Chen, Yuhong Liu, Jianbin Luo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Superlubricity at gold–graphite heterointerfaces can be easily achieved at the nanoscale because the different lattice parameters make them the promising friction pairs to form the incommensurate contact. However, the superlubricity under a high contact pressure at micro- or macro-scales, which has great implications in mechanical lubrication, remains unclear. In this study, a gold nanocrystal-coated probe was fabricated to form the multiple gold–graphite heterointerfaces in the contact zone, and the superlubricity was achieved under high contact pressures at ambient conditions. Friction coefficient reduced to the order of 0.001, and the scaling law of friction versus contact area satisfied the structural superlubricity model with a scaling power of γ = 0.08–0.36. The superlow friction can be attributed to the formation of structural superlubricity where the mismatched lattices at the multiple gold–graphite heterointerfaces ensure the incommensurate contact. These results extend the superlubricity of gold–graphite heterointerfaces to the practical level for the lubrication of micro- and nano-electromechanical systems.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300774-fx1.jpg" width="393" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Xiaoting Liu, Kai Pang, Hui Yang, Xingzhong Guo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Highly porous graphene aerogels (GAs) demonstrate extensive applications in damping blocks, thermal insulation, sensors, catalyst carriers and energy storage because of their ultralow density, superelasticity and functional versatility. These properties have been regulated by topological structural design and composite of materials, but the effect of the structural unit on the properties of GA has not been reported. Herein, highly porous GAs with excellent mechanical performances and improved adsorption capacities have been prepared by a freezing-drying process. Ultra-flyweight (〈em〉ρ〈/em〉 〈 1 mg cm〈sup〉−3〈/sup〉), superelastic (low energy loss factor) and high-strength (i.e., high Young’ modulus) aerogels can be obtained by integrating different wall thicknesses and pore sizes. And it has been found that the grain refinement of ice crystals has a positive impact on the strength and modulus of as-prepared GAs during freezing-drying, which is similar to typical Hall-Petch strengthening in fine crystal metal materials. The as-prepared GA with the thinnest wall thickness exhibits the highest adsorption properties with respect to the oil solvents, and the adsorption capacity is 1272 times of its own weight. This study enriches our understanding of the structure and performance of GAs and indicates a practical methodology to ensure precise structural control of high-performance GAs for various applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉We have intrinsically prepared ultra-flyweight, super-elastic, and high-strength graphene aerogels with extreme adsorption capacities by regulating their nano-scale wall thickness and pore size.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300725-fx1.jpg" width="246" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Alberto Bianco, Yuan Chen, Elzbieta Frackowiak, Michael Holzinger, Nikhil Koratkar, Vincent Meunier, Sergey Mikhailovsky, Michael Strano, Juan M.D. Tascon, Mauricio Terrones〈/p〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Wenda Li, Dezhu Wang, Zhijiang Gong, Xiaosong Guo, Jing Liu, Zhonghua Zhang, Guicun Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rechargeable non-aqueous potassium-ion batteries have been regarded as one of ideal candidates for large-scale electric energy storage applications. However, the achievement of high reversible capacity and rate capability is still a great challenge. In this work, an extraordinary S-/N-/O- multielement-doped three-dimensional (3D) flower-like hard carbon architecture is firstly proposed as promising anode material for low-cost potassium-ion batteries. The 3D flower-like architecture not only provides abundant exposed surface-active sites but acts as highly conductive interconnected network for electron transport. More encouragingly, the introduction of highly reactive -N-C〈sub〉〈em〉x〈/em〉〈/sub〉-S- species has been revealed to show highly reversible pseudo-capacitive charge storage behavior, inherently enlarging the slope reversible capacity to the highest value of 423 mAh g〈sup〉−1〈/sup〉 at low current density of 0.05 A g〈sup〉−1〈/sup〉. As well, benefitted from the structural and compositional advantages, an unprecedented rate capability (251 mAh g〈sup〉−1〈/sup〉 at 1.0 A g〈sup〉−1〈/sup〉) and stable cycling stability (362 mAh g〈sup〉−1〈/sup〉 after 300 cycles at 0.5 A g〈sup〉−1〈/sup〉) has been obtained, which outperforms most of carbonaceous materials for K-ion storage. Our present work not only provide new understandings on surface/conversion-synergistic driven K-ion storage mechanisms but offer effective material engineering strategies for improving the properties of potassium-ion batteries.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300592-fx1.jpg" width="267" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Yi Guo, Zoran Ristovski, Elizabeth Graham, Svetlana Stevanovic, Puneet Verma, Mohammad Jafari, Branka Miljevic, Richard Brown〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Four types of fuels blended with diesel in scaling proportion were used in a diesel engine to generate 13 different soot samples. The samples were characterised for their thermal-induced oxidation process with DSC and TGA from which the mass loss during each of three phases and 6 critical temperatures was obtained per sample. With the same samples, soot chemical structure was characterised by Raman, XPS and TEM. This analysis provided information on different carbon chemical structures, O/C ratio on the sample surface, and nanostructure (fringe length and tortuosity). It was observed that generally for oxygenated fuel blends, the soot samples are more reactive, have more O functional groups on the carbon layer edge plane and have smaller polyaromatic layer size than reference diesel soots, while aromatic fuel blends show the opposite trends. However, the trend was not distinctive for all the samples analysed. Nevertheless, the two groups of data are highly correlated which implies that the chemical structure is the underlying reason dominating the soot reactivity. Specifically, the soot samples with more O functional groups and/or C–C bonds on the edge plane, are more reactive, they lose more mass at the lower temperature range and require lower temperature to initiate oxidation.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300683-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Wen He, Rujun Ma, Dae Joon Kang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the latest trend of miniaturization of modern portable electronic devices, the development of small-sized, flexible power sources is in great demand. Herein, we report the fabrication of flexible and high-performance planar microsupercapacitors (MSCs) on a poly-ethylene terephthalate substrate as portable energy storage devices. We employed a facile laser printing technology and thermal crosslinking route to fabricate crosslinked polyaniline (PANI) based MSCs, taking advantage of the low processing cost and high cyclic stability. The flexible PANI MSCs after heat treatment in Argon atmosphere exhibited a remarkably high areal capacitance of 54 mF cm〈sup〉−2〈/sup〉 at the current density of 0.3 mA cm〈sup〉−2〈/sup〉, which is much higher than that of PANI MSCs reported so far elsewhere. 79.8% of the initial capacitance was retained after 1000 cycles, indicating the excellent cyclic stability of the devices. This innovative approach provides a new strategy for the facile fabrication of flexible and high-performance planar energy storage devices.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉We have successful fabricated the highly flexible planar PANI MSCs with outstanding electrochemical properties through a facile laser printing lithography approach following heat treatment.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300476-fx1.jpg" width="467" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Mani Mahajan, Kingshuk Roy, Swati Parmar, Gourav Singla, O.P. Pandey, K. Singh, Ramanathan Vaidhyanathan, Satishchandra Ogale〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉3D carbide systems with their robust physical and mechanical properties have always attracted multiple application interests. In this report, we have synthesized a three-dimensional in-situ carbon coated cubic carbide, Vanadium Carbide (VC@C), by a very simple, scalable and cost-effective room temperature mechano-chemical ball-milling procedure and researched its promise as effective anode material for Li and Na ion batteries. We have demonstrated that VC@C shows an impressive initial discharge/lithiation capacity of 1165 mAh g〈sup〉−1〈/sup〉 with a high reversible capacity of 640 mAh g〈sup〉−1〈/sup〉 after 100 charge-discharge cycles at an applied current density of 0.1 A g〈sup〉−1〈/sup〉. We have also found that this material renders a very promising rate performance with significantly low capacity drop after exposing it to variable current densities ranging from 0.05 A g〈sup〉−1〈/sup〉 to 2 A g〈sup〉−1〈/sup〉 with an excellent stability up to 1000 cycles owing to its structural robustness, as verified by post-cycling characterizations. A Li-ion full cell study using LiCoO〈sub〉2〈/sub〉 as cathode also showed excellent promise in terms of practical application demonstrating a reversible capacity of 95 mAh g〈sup〉−1〈/sup〉 after 100 cycles. Even for Na insertion/de-insertion VC@C shows a clear promise in terms of capacity, cyclic stability and rate performance.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300646-fx1.jpg" width="353" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Runyu Yan, Martin Oschatz, Feixiang Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Despite intensive research on porous carbon materials as hosts for sulfur in lithium-sulfur battery cathodes, it remains a problem to restrain the soluble lithium polysulfide intermediates for a long-term cycling stability without the use of metallic or metal-containing species. Here, we report the synthesis of nitrogen-doped carbon materials with hierarchical pore architecture and a core-shell-type particle design including an ordered mesoporous carbon core and a polar microporous carbon shell. The initial discharge capacity with a sulfur loading up to 72 wt% reaches over 900 mA h g〈sub〉sulfur〈/sub〉〈sup〉−1〈/sup〉 at a rate of C/2. Cycling performance measured at C/2 indicates ∼90% capacity retention over 250 cycles. In comparison to other carbon hosts, this architecture not only provides sufficient space for a high sulfur loading induced by the high-pore-volume particle core, but also enables a dual effect of physical and chemical confinement of the polysulfides to stabilize the cycle life by adsorbing the soluble intermediates in the polar microporous shell. This work elucidates a design principle for carbonaceous hosts that is capable to provide simultaneous physical-chemical confinement. This is necessary to overcome the shuttle effect towards stable lithium-sulfur battery cathodes, in the absence of additional membranes or inactive metal-based anchoring materials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300464-fx1.jpg" width="393" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Mehmet Emin Kilic, Kwang-Ryeol Lee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, Tetrahexcarbon (TH-carbon), a new two-dimensional(2D) carbon allotrope, has been identified with an intrinsic direct bandgap, which makes it promising for practical applications in optoelectronic devices. Using first-principles calculations, we examined the possibility of manipulating the physical and chemical properties of TH-carbon sheet by controlled hydrogenation. We systematically studied pristine TH-carbon and its hydrogenated derivatives with various configurations such as single- and double-sided hydrogenation. Our study revealed their stability in energetic, dynamic, thermal, and mechanical aspects. Depending on the hydrogen coverage and configurations, we observed the tunability of the phononic and electronic bandgap, and the direct-indirect-direct bandgap transitions. These results suggest the plausibility of modulating its electronic properties by hydrogenation. The heat transport in TH-carbon is anisotropic. A significant decrease in thermal conductivity was observed in the fully hydrogenated TH-carbon. The thermal conductivity in TH-carbon can be controlled by the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mi〉s〈/mi〉〈msup〉〈mrow〉〈mi〉p〈/mi〉〈/mrow〉〈mrow〉〈mn〉3〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 C–H low conduction domains. A notable increase in specific heat capacity was observed in hydrogenated derivatives of TH-carbon, which would make them useful in nanoscale engineering of thermal transport. The hydrogenation was found to reduce the in-plane stiffness and Young’s modulus, but increase the ultimate strength. These findings would provide important guidelines for practical applications of TH-carbon.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300270-fx1.jpg" width="497" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 16 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Alessandro Cresti, Jesús Carrete, Hanako Okuno, Tao Wang, Georg K.H. Madsen, Natalio Mingo, Pascal Pochet〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report on the structural and transport properties of the smallest dislocation loop in graphene, known as a flower defect. First, by means of advanced experimental imaging techniques, we deduce how flower defects are formed during recrystallization of chemical vapor deposited graphene. We propose that the flower defects arise from a bulge type mechanism in which the flower domains are the grains 〈em〉left over〈/em〉 by the dynamic recrystallization. Next, in order to evaluate the use of such defects as possible building blocks for all-graphene electronics, we combine multiscale modeling tools to investigate the structure and the electron and phonon transport properties of large monolayer graphene samples with a random distribution of flower defects. For large enough flower densities, we find that electron transport is strongly suppressed while, surprisingly, hole transport remains almost unaffected. These results suggest possible applications of flowered graphene for electron energy filtering. For the same defect densities, phonon transport is reduced by orders of magnitude as elastic scattering by defects becomes dominant. Heat transport by flexural phonons, key in graphene, is largely suppressed even for very low concentrations.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300403-fx1.jpg" width="497" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon〈/p〉 〈p〉Author(s): Zhiyu Zou, Virginia Carnevali, Laerte L. Patera, Matteo Jugovac, Cinzia Cepek, Maria Peressi, Giovanni Comelli, Cristina Africh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An 〈em〉operando〈/em〉 investigation of graphene growth on (100) grains of polycrystalline nickel (Ni) surfaces was performed by means of variable-temperature scanning tunneling microscopy complemented by density functional theory simulations. A clear description of the atomistic mechanisms ruling the graphene expansion process at the stepped regions of the substrate is provided, showing that different routes can be followed, depending on the height of the steps to be crossed. When a growing graphene flake reaches a monoatomic step, it extends jointly with the underlying Ni layer; for higher Ni edges, a different process, involving step retraction and graphene landing, becomes active. At step bunches, the latter mechanism leads to a peculiar ‘staircase formation’ behavior, where terraces of equal width form under the overgrowing graphene, driven by a balance in the energy cost between C–Ni bond formation and stress accumulation in the carbon layer. Our results represent a step towards bridging the material gap in searching new strategies and methods for the optimization of chemical vapor deposition graphene production on polycrystalline metal surfaces.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300397-fx1.jpg" width="280" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Buhe Bateer, Xiuwen Wang, Chungui Tian, Ying Xie, Kai Pan, Wenxiang Ping, Honggang Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rational microstructure design of carbon based composites is becoming a promising method to reinforce their electromagnetic (EM) wave absorption performance, but their synthesis remains a challenge. Herein, we have reported a design of small-size Ni〈sub〉2〈/sub〉P grown on carbon nanotubes (CNTs) as lightweight and high efficiency EM wave absorber. The Ni〈sub〉2〈/sub〉P NPs can be uniformly grown on CNTs by controlling the nucleation and growth rate of Ni〈sub〉2〈/sub〉P during the synthesis. The size and coverage of Ni〈sub〉2〈/sub〉P on CNTs can be tuned by adjusting the reaction conditions with a high yield, which is large favorable for adjusting their application performance. The Ni〈sub〉2〈/sub〉P/CNTs sample with low filler loading (30 wt%) in the paraffin wax exhibits a good wave absorption performance with the minimum reflection loss (RL mini) value of −51.8 dB at 5.28 GHz. Moreover, it shows a good EM wave absorption ability even at the thinnest thickness of 2 mm (−46.1 dB), and an effective absorption bandwidth of 11.68 GHz is achieved when the absorber thickness is in the range of 1.5–5 mm. The excellent EM wave absorbing performance makes the Ni〈sub〉2〈/sub〉P/CNTs as a promising new microwave absorbing material in sustainable filed.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The small-sized Ni〈sub〉2〈/sub〉P coated on carbon nanotubes were designed in high yields, which can be used as enhanced lightweight electromagnetic wave absorbers with the RL mini value of – 51.8 dB at 5.28 GHz.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622319312965-fx1.jpg" width="295" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 161〈/p〉 〈p〉Author(s): Kaixiang Zou, Zixing Guan, Yuanfu Deng, Guohua Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High performance N-doping porous carbon (NDPC) are ideal electrode materials for Li-ion capacitors (LICs). However, the practical application of NDPC is extremely limited, which is mainly attributed to the typical methods for the scale preparation NDPC are time-consuming, high cost and low yield. Herein, we have developed a new route for high efficient, environment friendly, low cost and high yield fabrication of NDPC, using biomass waste as the carbon source and a novel eutectic salt as the activation agent. After a series of comparative experiments, the application of eutectic salt herein not only reduce the process time and cost, but also obviously enhance the yield, the specific surface area (SSA) and nitrogen-doping content of NDPC sample (labelled as NDPC-0.5). In combination of the rich N-doping level, larger SSA and interconnected porous structure, the NDPC-0.5 sample exhibit an excellent electrochemical performance as both cathode and anode materials for a LIC, with specific discharge capacities of ∼60 and 290 mAh g〈sup〉−1〈/sup〉 at a current density of 5 A g〈sup〉−1〈/sup〉. The resultant NDPC-0.5//NDPC-0.5 LIC device delivers a high energy density of 116.9 Wh kg〈sup〉−1〈/sup〉 at 500 W kg〈sup〉−1〈/sup〉, with a capacity retention of 81% after 8000 cycles at 2 A g〈sup〉−1〈/sup〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622320300452-fx1.jpg" width="497" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉