摘要
FeS因具有较高的比容量和优异的环境友好性,被认为是一种极具竞争力的锂/钠离子电池负极材料.然而,循环过程中缓慢的电荷转移动力学和较大的体积变化阻碍了它的实际应用.本文通过在超薄FeS/C复合材料中构建应变缓冲(气泡膜状)结构,从根本上解决了FeS动力学缓慢和体积变化大的问题.有限元模拟和非原位透射电镜结果验证了气泡膜状碳基质可作为保护壳层缓解FeS的巨大体积变化,还能提高其电子导电性.得益于这种独特的结构设计,该电极材料表现出显著增强的性能.其在5 A g^(-1)下的储锂容量为469 mA h g^(-1),在1 A g^(-1)下循环1500次后的储钠容量为354 mA h g^(-1).此外,由该电极与LiFePO_(4)正极组装的全电池即使在100次循环后也能提供558 mA h g^(-1)的比容量,展现出优异的循环稳定性.这一策略也可应用于其它导电性差、体积变化大的负极材料,以促进高倍率和长寿命电池的发展.
Iron sulfide(FeS)is a competitive anode material for Li-/Na-ion batteries(LIBs/SIBs)with high specific capacity and excellent environmental benignity.Nevertheless,its practical application is greatly hindered by the sluggish charge transfer dynamics and large volume variations upon cycling.Herein,by constructing a strain-alleviated(bubble film-like)structure in an ultrathin FeS/C composite,the sluggish transfer kinetics and huge volume variations of FeS were fundamentally solved.The bubble film-like carbon matrix serves as the protective shell to alleviate the huge volume changes of FeS and enhance its electronic conductivity,as verified by finite element simulation and ex-situ transmission electron microscopy results.Benefiting from this unique design,the as-designed electrode exhibited a significantly enhanced performance with a high discharge capacity of 469 mA h g^(−1)at 5 A g^(−1)for LIBs and 354 mA h g^(−1)after 1500 cycles at 1 A g^(−1)for SIBs.Moreover,the full cell with this electrode and LiFePO_(4)cathode can deliver outstanding cycling stability of 558 mA h g^(−1)even after 100 cycles.We expect that this strategy can also be applied to other anode materials plagued by poor conductivity and huge volume changes and remarkably spur the development of batteries with high rate capability and long lifespan.
作者
黄肖
何琼
寻坚
潘泰松
周双
曹国忠
潘安强
Xiao Huang;Qiong He;Jian Xun;Taisong Pan;Shuang Zhou;Guozhong Cao;Anqiang Pan(School of Materials and Energy,University of Electronic Science and Technology of China,Chengdu 611731,China;School of Materials Science and Engineering,Central South University,Changsha 410083,China;Hunan Aerospace Institute of Electromechanical Device&Special Materials,Changsha 410006,China;Department of Materials Science and Engineering,University of Washington,Seattle,WA 98195,USA)
基金
supported by the National Natural Science Foundation of China(51874362)。
