摘要
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.
作者
Linjie Chen
Keming Song
Juan Shi
Jiyu Zhang
Liwei Mi
Weihua Chen
Chuntai Liu
Changyu Shen
陈琳洁;宋轲铭;石娟;张继雨;米立伟;陈卫华;刘春太;申长雨(National Engineering and Research Center for Advanced Polymer Processing Technology,Zhengzhou University,Zhengzhou,450001,China;Green Catalysis Center,and College of Chemistry,Zhengzhou University,Zhengzhou,450001,China;Center of Advanced Materials Research,Zhongyuan University of Technology,Zhengzhou,450007,China)
基金
supported by the National Natural Science Foundation of China(U1804129,21771164,21671205 and U1804126)
Zhongyuan Youth Talent Support Program of Henan Province
Zhengzhou University Youth Innovation Program。
