ALBERT

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Soner Çakar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a novel 1–10 phenanthroline and 1–10 phenanthroline 5,6 diol based metal complex sensitizers for dyes sensitized solar cells applications is investigated. The 1–10 phenanthroline 5,6 diol structure is formed by the addition of two –OH groups to 1–10 phenanthroline, which has higher cell yields due to binding sites of TiO〈sub〉2〈/sub〉. The 1–10 phenanthroline 5,6 diol metal complexes are prepared with Cu and Fe at different pH values. Additionally, these metal complexes are mixed at different ratio to prepare cocktail dyes. The maximum cell efficiency value of dyes sensitized solar cells based on 1–10 phenanthroline 5,6 diol prepared with Cu:Fe 2:1 ratio cocktail dyes is 3.70%. The phen-ol based DSSC containing Cu-complex dye exhibits 2.80% conversion efficiency value, which shows an 25% lower than cocktail phen-ol based dyes sensitized solar cells. The solar cell efficiency values are demonstrated decrement by increasing of Fe-complex ratio. However, the Fe-complexes exhibit more stable complex structures than Cu-complexes. This phenomenon also gives a new way to the use of the environmentally friendly metal complex-based dyes sensitized solar cells. Additionally, these transition metal-based sensitizers will be an alternative to synthetic organic dyes and noble metal-based solar cells.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Weiping Diao, Saurabh Saxena, Michael Pecht〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Accelerated cycle life testing of lithium-ion batteries is conducted as a means to assess whether a battery will meet its life cycle requirements. This paper presents a study to identify optimal accelerated cycle testing conditions for LiCoO〈sub〉2〈/sub〉-graphite cells. A full factorial design of experiment with three stress factors—ambient temperature (10 °C, 25 °C, 45 °C, 60 °C), discharge current rate (C-rate, 0.7C, 1C, 2C), and charge cut-off C-rate (C/5, C/40)—is used to study the effects of these stress factors on battery capacity fade and to obtain the data necessary for decision making. An empirical accelerated degradation model is then developed to capture the characteristics of the two-stage capacity degradation process, along with an accelerated test planning approach.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Linna Dai, Qing Sun, Jianguang Guo, Jun Cheng, Xiaoyan Xu, Huanhuan Guo, Deping Li, Long Chen, Pengchao Si, Jun Lou, Lijie Ci〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Li-O〈sub〉2〈/sub〉 batteries are considered as one of the future candidates for electrochemical power sources due to their high theoretical energy density. As the dominating component affects the performance of Li-O〈sub〉2〈/sub〉 batteries, O〈sub〉2〈/sub〉-cathode catalyst with high efficiency, low price, facile preparation is important. Herein, polyhedral and porous Mn〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 rods are fabricated for cathode catalysts in Li-O〈sub〉2〈/sub〉 batteries via electrospinning method followed by calcination. The Mn〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 catalyst possesses a three-dimensional porous structure, which can offer good catalytic activity, expose plenty of active sites and improve the diffusion of electrolyte and O〈sub〉2〈/sub〉. When employed as the cathode catalyst, the Li-O〈sub〉2〈/sub〉 batteries show enhanced initial discharge capacity of 9701 mA h g〈sup〉−1〈/sup〉 at a current density of 200 mA g〈sup〉−1〈/sup〉, superior rate capacity and good cycling stability within 160 cycles at the capacity of 500 mA h g〈sup〉−1〈/sup〉. These enhanced performances demonstrate a facile method to fabricate Mn〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 with unique structure as a promising catalytic material for Li-O〈sub〉2〈/sub〉 batteries.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Yong Zhang, Guangwu Wen, Shan Fan, Yuanyuan Chu, Shuhua Li, Baoyun Xu, Jing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, three-dimensional phenolic hydroxyl functionalized partially reduced graphene oxides with high hydroxyl content and significantly enhanced electrochemical performance have been successfully prepared by a one-pot hydrothermal method from graphene oxide dispersions. A very small amount of 4-aminophenol is employed as reducing and N-doping agent, structure modifier and the phenolic hydroxyl source, at the same time. The electrochemical test results show that as binder-free electrode, the as-synthesized sample with high hydroxyl content (6.15 at%) exhibits an ultrahigh specific capacitance of 284.1 F g〈sup〉−1〈/sup〉 at current density of 0.3 A g〈sup〉−1〈/sup〉 in 6 M KOH electrolyte, and retains for 80.4% even at a current density of 10 A g〈sup〉−1〈/sup〉. Above all, the as-assembled symmetric supercapacitor shows superior energy density of 9.9 Wh kg〈sup〉−1〈/sup〉 at a power density of 75.0 W kg〈sup〉−1〈/sup〉. The significantly enhanced electrochemical performance can be ascribed to the high hydroxyl content and other oxygen functional groups, N-doping, modified porous framework and the high specific surface area of the graphene. Those special characteristics suggest that the as-synthesized graphene materials may have potential applications in high performance supercapacitors.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307840-fx1.jpg" width="330" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Anna Slesarenko, Igor K. Yakuschenko, Vahid Ramezankhani, Visweshwar Sivasankaran, Olga Romanyuk, Alexander V. Mumyatov, Ivan Zhidkov, Sergey Tsarev, Ernst Z. Kurmaev, Alexander F. Shestakov, Olga V. Yarmolenko, Keith J. Stevenson, Pavel A. Troshin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report a facile synthesis of octahydroxytetraazapentacene (OHTAP) and the application of this redox-active material as a cathode for lithium- and potassium-ion batteries. While testing in lithium half-cells, OHTAP was used in the form of lithium salt and delivered the specific discharge capacity of 〉400 mAh g〈sup〉−1〈/sup〉 and the energy density of ~700 Wh kg〈sup〉−1〈/sup〉, which are impressive values achieved for organic electrode materials and can also be favorably compared with the characteristics of the current commercial benchmark cathodes based on LiFePO〈sub〉4〈/sub〉 (~155 mAh g〈sup〉−1〈/sup〉 and 543 Wh kg〈sup〉−1〈/sup〉). The potassium half-cells fabricated using pristine OHTAP depending on the electrode deposition technique showed specific capacities of 120–220 mAh g〈sup〉−1〈/sup〉, which are among the record values reported so far for this type of batteries. Quantum chemical DFT modelling provided insights in the mechanistic aspects of metallation of OHTAP and revealed that lithium- and potassium-ion storage might involve both the hydroquinone-quione chemistry as well as the redox transformations of pyrazine rings.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319306950-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Meetu Bharti, Ajay Singh, Gajender Saini, Sudeshna Saha, Anil Bohra, Yuki Kaneko, A.K. Debnath, K.P. Muthe, Kazuhiro Marumoto, D.K. Aswal, S.C. Gadkari〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We demonstrate that introduction of p-type Bi〈sub〉0.5〈/sub〉Sb〈sub〉1.5〈/sub〉Te〈sub〉3〈/sub〉 nanostructures into the polymer matrix not only causes highly adherent drop-casted films of PEDOT:PSS (on Kapton sheets) to attain a free-standing nature but also brings a significant improvement in their thermoelectric properties. Hall and ESR measurements of these hybrid films clearly show that both the carrier concentration and mobility can be varied with Bi〈sub〉0.5〈/sub〉Sb〈sub〉1.5〈/sub〉Te〈sub〉3〈/sub〉 content. Whereas, results of X-ray diffraction, Raman and X-ray photoelectron spectroscopy confirm the enhancement in chain alignment and better connectivity among PEDOT:PSS and Bi〈sub〉0.5〈/sub〉Sb〈sub〉1.5〈/sub〉Te〈sub〉3〈/sub〉 nanosheets; leading to remarkable enhancement of electrical conductivity. These hybrid films, due to energy filtering of charge carriers at the organic/inorganic interface, exhibit improvement in the Seebeck coefficient also. In fact, such a synergetic combination of improved electrical conductivity and Seebeck coefficient expertly tailors the power factor (from order of ~10〈sup〉−4〈/sup〉 to 8.3 μW/mK〈sup〉2〈/sup〉) over a vast range. The optimized films are tested for their power conversion ability and a single thermoelement based device exhibits an open circuit voltage ~536 μV and current ~134 μA for a temperature difference of 53 °C. Such an evolution of organic-inorganic hybrid films in a flexible, free-standing motif with enhanced thermoelectric properties exhibit good potential for recovering heat from the curved hot surfaces.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307293-fx1.jpg" width="252" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Mohammed Srout, Karima Lasri, Mouad Dahbi, Abdelkader Kara, Laurene Tetard, Ismael Saadoune〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Being considered as a high Li-ion mobility material, Nasicon structured Li〈sub〉1.5〈/sub〉Fe〈sub〉0.5〈/sub〉Ti〈sub〉1.5〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉 phosphate material was synthesized via sol-gel route and electrochemically tested as electrode material for lithium-ion batteries. The material was tested in half-lithium electrochemical cells, within two voltage windows, 1.5–3.0 V and 0.5–3.0 V, and delivered first discharge capacities of 129 mAh/g and 567 mAh/g, respectively. Raman spectroscopy was used to confirm the material's structure before and during cycling. In addition, a comparative study of the electrochemical performance by the use of two different binders (PVDF and CMC), was conducted and showed a significant change in the electrochemical performance due to the change of the binder. Electrochemical impedance spectroscopy was used to evidence the electrodes' interface changes during cycling.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Kingo Ariyoshi, Satoshi Mizutani, Yusuke Yamada〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrochemical impedance analysis was performed for Li[Li〈sub〉0.1〈/sub〉Al〈sub〉0.1〈/sub〉Mn〈sub〉1.8〈/sub〉]O〈sub〉4〈/sub〉 (LAMO) used as a lithium-insertion electrode by the diluted electrode method to identify the origin of resistance. Utilization of diluted electrodes, in which some portion of active material, LAMO, was systematically replaced with the same amounts of spectator Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 material to maintain the original structure of the LAMO electrode, is a promising method to discriminate between the resistance attributed to the lithium-insertion reaction in LAMO (charge-transfer resistance) and that accompanied by conduction of electron and/or ion in the porous electrodes. Electrochemical impedance spectra of the diluted electrodes consisted of two semicircles. The radius of a semicircle in the lower frequency region depends on the LAMO content in a diluted electrode, indicating that the semicircle is associated with charge-transfer resistance. On the other hand, the radius of the other semicircle in the higher frequency region is independent of the LAMO contents, suggesting that the semicircle is mainly related to the resistance accompanied by the porous structure of electrodes. Thus, the structure of lithium-insertion electrode should be carefully considered in designing high-energy and high-power lithium-ion batteries that employ thick electrodes.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Rajesh Thomas, Shashikant P. Patole, Pedro M.F.J. Costa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electrochemical storage of aluminum in graphitic electrodes is a topic of much interest in the search for alternative battery systems. Here, we show that an Al-based battery can be realized using a cathode assembled with graphene flakes obtained from processed expandable graphite. When compared to pristine graphite (in this work, with 45 mAh/g at a current density of 214 mA/g), the capacity and cycle life performance are notably increased by the use of the graphene flakes (172 mAh/g, at 214 mA/g, after 100 cycles). The location and persistence of the charged choloraluminate species in the carbon materials was experimentally analyzed and complemented with computational modelling. Accordingly, and besides intercalation, grafting of the Al-species onto the graphene layers was identified as a possible mechanism that enhanced the performance of the processed expandable graphite cathodes. Such a phenomena would make the electrode more conductive and introduce a path for charge storage on its surface (akin to faradaic supercapacitors).〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307517-fx1.jpg" width="443" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Elizabeth Whiddon, Haihui Zhu, Xiuping Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Salinity gradient (SG) energy is a renewable and clean energy resource that exists worldwide from the change in Gibbs free energy when two solutions with different salinities are mixed. More recently, concentration flow cells (CFCs) have been introduced as a new technology for SG energy recovery with the highest reported power density output to date as a result of the utilization of both the electrode potential and Donnan potential. In this study, multiple CFCs are connected to form a consecutive number of stacks, and systematic analysis is conducted to investigate the influence of both parallel and series electrical wire connections on the overall performance. For both wire connections, an effective increase in the overall power output with an increase in stack size is observed. The power densities normalized to the membrane area are however lower (3.7 W m〈sup〉−2〈/sup〉 in series and 5.8 W m〈sup〉−2〈/sup〉 in parallel, for 5-stacks) than that of the individual cell unit (8.9 W m〈sup〉−2〈/sup〉) because the back of the stack experiences cumulative mixing. Additionally, as a result of an ionic cross-conduction causing a parasitic current in the series cell, the parallel wire configuration is demonstrated to be more successful in the CFC stack than the series.〈/p〉〈/div〉 〈/div〉