【作者】 彭振桓； 邓青林； 沈维超； 康蕊； 张家培； 赵宏滨； 徐甲强；

【Author】 Zhenhuan PENG~a,Qinglin DENG~a,Weichao SHEN~b,Rui KANG~b,Jiapei ZHANG~b,Hongbin ZHAO~(*a),Jiaqiang XU~(*a) a Department of Chemistry,College of Science,Shanghai University,Shanghai,200444,China; b Residential College,Shanghai University Shanghai,200444,China

【机构】 上海大学理学院化学系； 上海大学社区学院；

【摘要】 含硫正极材料具有环境友好、成本低廉、能量密度高等特性,因此锂硫电池在电动汽车电源等方面展现了诱人的应用前景。但由于单质硫本身导电性极差,且容易形成多硫化物溶解进入电解液中,制约了其利用率和循环性能。为解决这一问题,笔者将硫包埋在导电聚合物巾形成核壳结构以改善其性能。实验结果表明:使用聚吡咯(PPv)包覆硫的锂硫电池正极材料具有良好的容量保持率,其循环性能显著提高。首次充电容量1200mAh/g,放电容量980 mAh/g,20次循环容量保持率在85%PX上。进一步的分析表明:在充放电循环过程中,PPy形成的网状结构能够容纳和释放多硫化物,从而显著地抑制了其在电解液巾的溶解。在研究中我们还发现:除控制导电聚合物PPy层的厚度外,掺杂聚阴离子同样可以显著提升电池的循环性能。可以预料,在对PPy层和多硫化物之间的界面行为进行更加深入的研究后,我们可以在设计制造长循环寿命锂硫电池方面取得更大的进展。更多还原

【Abstract】 Sulfur as cathodic material of rechargeable batteries is attractive for electric transportation for their environmentally friendliness,low cost,and superior energy density.However,elemental sulfur is not applied effectively as lithium rechargeable batteries,owing to its drawbacks,namely,soluble polysulfide formation and low conductivity.To tackle this issue,we present here a strategy based on the use of a conducting polymer layer as shell for sulfur impregnation.Electrodes containing sulfur coated with polypyrrole(PPy) were found to show a marked increase in the capacity retention of Li-S cathodes,especially for the cycling performance.The initial charging capacity is 1200 mAh/g and the corresponding discharging capacity is 980 mAh/g.After 20 cycles,85%of the capacity is maintained.Results for complementary analysis demonstrated the reversible capture and release of the polysulfides by the net of PPy during cycling and evidenced an inhibitory action of polysulfide dissolution by PPy coating.Besides polymer layer thickness,the polyanion doping of the conducting polymers,as observed for the PPy,appears to also have a pronounced effect on enhancing the cycle performance.Increased knowledge about the interface between polysulfide species and PPy surfaces could lead to novel approaches in the design and fabrication of long cycle life S electrodes.更多还原