硅基负极与电解液化学反应的分析与抑制策略

The analyses and suppressing strategies of silicon anode with the electrolyte

硅基材料因其高能量密度、适中的充放电平台以及丰富的储量成为最具有潜力的下一代锂离子电池负极材料,但其较差的循环稳定性是目前硅基负极材料应用的瓶颈。目前的研究主要通过导电性改进、控制体积膨胀和改进固体电解质界面这三方面来改进材料,并取得了一定的效果。但是,目前的改进主要是从电化学的角度出发,忽略了硅基材料与电解液之间的本征化学反应。本文综述了清华大学化工系魏飞课题组近年来在硅基负极与电解液本征化学反应分析与抑制策略的系列工作,从硅基材料与电解液的反应动力学出发,发现了影响硅基负极界面稳定性的另外因素,对其进行深入研究的基础上,提出了抑制副反应的有效策略,研究了抑制本征化学反应的策略。结果表明,通过引入陶瓷包覆层形成规整人造SEI层,在保证锂离子和电子的传输前提下,可有效抑制硅基材料与电解液的化学反应。本文对硅基材料与电解液的本征化学反应的抑制提出了有效策略,为提高硅基负极材料循环稳定性提供了新思路,有效指导了硅基负极材料的发展。

Owing to its high energy density,moderate charging and discharging platform,and abundant reserves,silicon-based material has emerged as one of the most promising anode materials for lithium-ion batteries.However,its low cyclic stability limits its usefulness.To date,previous studies have mainly concentrated on electrochemically driven interfacial reactions during cycling and have neglected the intrinsic chemical reactivity between the anode and the electrolyte.This paper reviews previous research on the intrinsic reaction between silicon and electrolyte and strategies for suppressing the side reaction.Other factors affecting the interface stability of silicon base anode were discovered on the basis of the reaction kinetics of silicon base material and electrolyte,and effective strategies for inhibiting side reactions were proposed.To suppress the side reaction effectively,a protective layer should be designed on the surface of silicon,which could suppress the penetration of fluorine to protect the silicon.Furthermore,the protective layer should have the ability to allow the lithium ion and electron to pass through.An appealing perspective was proposed to improve the performance of silicon anodes and effectively guide their development.