LAUSR

High-capacity metal chalcogenides often suffer from low initial coulombic efficiency (ICE) and serious capacity fading owing to the shuttle effect and volumetric expansion. Various carbon-coating and fixing methods were used to improve the above-mentioned performance. However, the synthesis processes of them are complex and time-consuming, limiting their engineering applications. Herein, polar polymer binder sodium polyacrylate (PAANa) is selected as an example to solve the problems of metal chalcogenides (bare micro-sized FeS) without any modification of the active materials. The special function of the polymer binder in the interface between the active material particles and the electrolytes demonstrates that a PAANa-induced network structure on the surface of ion sulfide microparticles not only buffers the mechanical stress of particles during discharging-charging, but also participates in forming a ductile solid electrolyte interphase (SEI) with high interfacial ion transportation and enhanced ICE. The cyclic stability and rate performance can be simultaneously improved. This work not only provides a new understanding of the binder on electrode, but also introduces a new way to improve the performance of batteries. 高容量金属硫化物面临着首周库伦效率低、 穿梭效应和体积膨胀等导致的严重容量衰退问题, 碳包覆和固定常被用来解决上述问题. 然而, 这些方法通常比较复杂、 耗时, 不利于大规模应用. 本文提出一种采用粘结剂优化解决微米级FeS电极材料上述问题的简便策略, 以极性聚合物粘结剂聚丙烯酸钠(PAANa)为例, 研究了其作用机制: PAANa粘结剂的引入可与FeS材料颗粒形成交联的网状结构, 既可以缓冲电极材料在充放电时体积的改变所产生的机械应力, 还诱导并参与在FeS颗粒表面形成较薄的SEI膜, 提高了电极界面离子迁移速度和电极的首周库伦效率, 使得FeS负极的循环稳定性和倍率性能得到明显优化. 本工作不仅使人们对电极粘结剂在电极中的作用有了新的认识, 而且为优化电池材料性能提供了新途径.