锂离子电池硅氧化物负极首次库伦效率的影响因素与提升策略

硅氧化物(SiO_x, 0<x≤2)具有高的比容量和低的嵌锂电位, 且体积膨胀率显著低于纯硅负极, 因而被认为是替代传统石墨负极材料的理想选择之一. 然而SiO_x负极在首次嵌锂过程中表面形成的固体电解质界面膜(SEI)以及大量的不可逆产物, 造成其首次库伦效率偏低, 严重阻碍了SiO_x负极的实际应用. 本文从SiO_x的结构模型出发, 系统阐述了SiO_x负极的嵌锂机理以及首次库伦效率低的原因; 归纳了SiO_x负极首次库伦效率的提升策略及其研究进展; 并对提升SiO_x负极首次库伦效率的未来发展方向进行了展望.

Influencing Factors and Promotion Strategies of the First-cycle Coulombic Efficiency of Silicon Suboxide Anodes in Lithium-ion Batteries

The popularity of electric vehicles and various portable electronic devices has led to higher demands on battery energy density. Silicon suboxide（SiO_x， 0<x≤2） shows high specific capacity and low Li-ion insertion potential， and the volume expansion effect is significantly lower than that of pure silicon anode， and therefore is considered to be one of the ideal alternatives to traditional graphite anode materials. However， the solid electrolyte interphase（SEI） and a large number of irreversible products are formed during the first lithiation/delithiation cycle， resulting in low Coulombic efficiency， which seriously hinders the practical application of SiO_x anodes. On the basis of SiO_x structure， this review systematically explained the lithium storage mechanism of SiO_x anode and the reason for the low first-cycle efficiency. Further， strategies of improving the first Coulombic efficiency of SiO_x anode in recent years is summarized in detail. Finally， the future direction of improving the first-cycle efficiency of SiO_x anode is also forecasted.