The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Lynden A Archer - One of the best experts on this subject based on the ideXlab platform.
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metal sulfur battery cathodes based on pan sulfur composites
Journal of the American Chemical Society, 2015Co-Authors: Shuya Wei, Kenville E Hendrickson, Lynden A ArcherAbstract:Sulfur/Polyacrylonitrile composites provide a promising route toward cathode materials that overcome multiple, stubborn technical barriers to high-energy, rechargeable lithium-sulfur (Li-S) cells. Using a facile thermal synthesis procedure in which sulfur and Polyacrylonitrile (PAN) are the only reactants, we create a family of sulfur/PAN (SPAN) nanocomposites in which sulfur is maintained as S3/S2 during all stages of the redox process. By entrapping these smaller molecular sulfur species in the cathode through covalent bonding to and physical confinement in a conductive host, these materials are shown to completely eliminate polysulfide dissolution and shuttling between lithium anode and sulfur cathode. We also show that, in the absence of any of the usual salt additives required to stabilize the anode in traditional Li-S cells, Li-SPAN cells cycle trouble free and at high Coulombic efficiencies in simple carbonate electrolytes. Electrochemical and spectroscopic analysis of the SPAN cathodes at various stages of charge and discharge further show a full and reversible reduction and oxidation between elemental sulfur and Li-ions in the electrolyte to produce Li2S as the only discharge product over hundreds of cycles of charge and discharge at fixed current densities.
Yan Zhao - One of the best experts on this subject based on the ideXlab platform.
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binding mechanism of sulfur and dehydrogenated Polyacrylonitrile in sulfur polymer composite cathode
Journal of Power Sources, 2013Co-Authors: Mahmoudreza Ghaznavi, Yan Zhao, Yongguang Zhang, Aishuak Konarov, Mikhail Sadhu, Ravichandra Tangirala, P ChenAbstract:A composite consisting of sulfur/dehydrogenated Polyacrylonitrile is one of the most promising cathode materials for use in rechargeable lithium–sulfur batteries. However, the reported sulfur contents have been low, less than 50 wt%, which compromise the intrinsic high specific capacity and energy of elemental sulfur and hence decrease significantly the specific energy of the composite. To identify the potential to further increase the sulfur content, we elucidate the binding mechanism of sulfur and Polyacrylonitrile in their composite. The heat treatment experiments at varying timespans with excess sulfur showed a constancy of sulfur content after a critical length of timespan, indicating the saturation of sulfur in the structure of dehydrogenated Polyacrylonitrile. Based on molecular structure and size consideration, it is proposed that the binding involves the formation of an 8 membered ring of sulfur embedded between 4 heterocyclic rings of dehydrogenated Polyacrylonitrile. From this model and experimental results, we show that there exists an upper limit of sulfur content in the sulfur/dehydrogenated Polyacrylonitrile composite at 56 wt%.
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synthesis and characterization of Polyacrylonitrile 2 amino 2 thiazoline resin and its sorption behaviors for noble metal ions
Reactive & Functional Polymers, 2003Co-Authors: Yiyong Chen, Yan ZhaoAbstract:Abstract Polyacrylonitrile-2-amino-2-thiazoline resin (PAN-ATAL) was synthesized from macroporous type crosslinked Polyacrylonitrile and 2-amino-2-thiazoline. The functional group capacity and percentage conversion of functional group of PAN-ATAL prepared under the optimum condition were 2.002 mmol FG/g and 15.90%, respectively. The structure of PAN-ATAL was confirmed by elemental analysis and X-ray photoelectron spectroscopy (XPS). The sorption capacities of PAN-ATAL for Rh(III), Ru(IV), Ir(IV) and Pd(II) were 72.07, 137.6, 147.1 and 230.7 mg/g resin, respectively. PAN-ATAL resin has excellent sorption selectivity for Pd(II) and Rh(III) in the presence of common metal ions over a wide acidity range. The sorption rate constants of PAN-ATAL resin for Rh(III) and Ir(IV) were determined. The apparent sorption activation energy ( E a ) of PAN-ATAL for Ru(IV) and Ir(IV) was 58.8±0.6 kJ mol −1 and 65.9±0.9 kJ mol −1 , respectively.
Lixia Yuan - One of the best experts on this subject based on the ideXlab platform.
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ether compatible sulfurized Polyacrylonitrile cathode with excellent performance enabled by fast kinetics via selenium doping
Nature Communications, 2019Co-Authors: Xin Chen, Lihui Wang, Jiaqiang Yang, Linfeng Peng, Bin Shan, Zhangxiang Hao, Jingwei Xiang, Kai Yuan, Yunhui Huang, Lixia YuanAbstract:Sulfurized Polyacrylonitrile is suggested to contain Sn (n ≤ 4) and shows good electrochemical performance in carbonate electrolytes for lithium sulfur batteries. However inferior results in ether electrolytes suggest that high solubility of Li2Sn (n ≤ 4) trumps the limited redox conversion, leading to dissolution and shuttling. Here, we introduce a small amount of selenium in sulfurized Polyacrylonitrile to accelerate the redox conversion, delivering excellent performance in both carbonate and ether electrolytes, including high reversible capacity (1300 mA h g−1 at 0.2 A g−1), 84% active material utilization and high rate (capacity up to 900 mA h g−1 at 10 A g−1). These cathodes can undergo 800 cycles with nearly 100% Coulombic efficiency and ultralow 0.029% capacity decay per cycle. Polysulfide dissolution is successfully suppressed by enhanced reaction kinetics. This work demonstrates an ether compatible sulfur cathode involving intermediate Li2Sn (n ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries. Lithium sulfur batteries are promising for advanced energy storage, but polysulfide shuttling limits performance lifetime. Here the authors report selenium-doping in a sulfur-based cathode to prevent dissolution of polysulfide intermediates, leading to ether compatibility, high capacity and stable cycling.
Xin Chen - One of the best experts on this subject based on the ideXlab platform.
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effect of eutectic accelerator in selenium doped sulfurized Polyacrylonitrile for high performance room temperature sodium sulfur batteries
Journal of Materials Chemistry, 2019Co-Authors: Lihui Wang, Xin Chen, Jiaqiang Yang, Yulong Sun, Linfeng Peng, Bin Shan, Jia XieAbstract:Sulfurized Polyacrylonitrile is a suitable cathode candidate for room temperature sodium–sulfur batteries. However, its limited reactivity results in low utilization of active materials, limited rate capability and poor cycling performance especially in ether electrolyte. Here, we demonstrate the effect of using selenium as a eutectic accelerator in sulfurized Polyacrylonitrile in which a small amount of selenium is easily distributed at the molecular level and leads to significant improvement of reaction kinetics. As a result, the designed Se0.08S0.92@pPAN cathode exhibits superior rate and cycle performance as well as compatibility with both ether and carbonate electrolytes, delivers capacities of 1214 and 767 mA h g−1 at 0.1 and 3 A g−1 respectively, and maintains a good specific capacity of 770 mA h g−1 at 0.4 A g−1 over 500 cycles (0.045% decay per cycle) in carbonate electrolyte with nearly 100% coulombic efficiency. Furthermore, self-discharge tests reveal diminished soluble sodium polysulfides owing to the fast redox conversion enabled by Se-doping.
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ether compatible sulfurized Polyacrylonitrile cathode with excellent performance enabled by fast kinetics via selenium doping
Nature Communications, 2019Co-Authors: Xin Chen, Lihui Wang, Jiaqiang Yang, Linfeng Peng, Bin Shan, Zhangxiang Hao, Jingwei Xiang, Kai Yuan, Yunhui Huang, Lixia YuanAbstract:Sulfurized Polyacrylonitrile is suggested to contain Sn (n ≤ 4) and shows good electrochemical performance in carbonate electrolytes for lithium sulfur batteries. However inferior results in ether electrolytes suggest that high solubility of Li2Sn (n ≤ 4) trumps the limited redox conversion, leading to dissolution and shuttling. Here, we introduce a small amount of selenium in sulfurized Polyacrylonitrile to accelerate the redox conversion, delivering excellent performance in both carbonate and ether electrolytes, including high reversible capacity (1300 mA h g−1 at 0.2 A g−1), 84% active material utilization and high rate (capacity up to 900 mA h g−1 at 10 A g−1). These cathodes can undergo 800 cycles with nearly 100% Coulombic efficiency and ultralow 0.029% capacity decay per cycle. Polysulfide dissolution is successfully suppressed by enhanced reaction kinetics. This work demonstrates an ether compatible sulfur cathode involving intermediate Li2Sn (n ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries. Lithium sulfur batteries are promising for advanced energy storage, but polysulfide shuttling limits performance lifetime. Here the authors report selenium-doping in a sulfur-based cathode to prevent dissolution of polysulfide intermediates, leading to ether compatibility, high capacity and stable cycling.
Sheng S Zhang - One of the best experts on this subject based on the ideXlab platform.
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understanding of sulfurized Polyacrylonitrile for superior performance lithium sulfur battery
Energies, 2014Co-Authors: Sheng S ZhangAbstract:Sulfurized Polyacrylonitrile (SPAN) is one of the most important sulfurized carbon materials that can potentially be coupled with the carbonaceous anode to fabricate a safe and low cost “all carbon” lithium-ion battery. However, its chemical structure and electrochemical properties have been poorly understood. In this discussion, we analyze the previously published data in combination with our own results to propose a more reasonable chemical structure that consists of short –Sx– chains covalently bonded onto cyclized, partially dehydrogenated, and ribbon-like Polyacrylonitrile backbones. The proposed structure fits all previous structural characterizations and explains many unique electrochemical phenomena that were observed from the Li/SPAN cells but have not been understood clearly.
