薄膜厚度对α-SiO_x薄膜负极电化学性能的影响（英文）

Influence of Film Thickness on the Electrochemical Performance of α-SiO_x Thin-film Anodes

近年来, SiO_x作为锂离子电池负极,由于其良好的循环稳定性、较大的容量以及对成分调控的可行性,引起了广泛的关注。以往的许多研究都集中在阐明氧含量对SiO_x负极的影响,尺寸效应对性能的影响规律很少被研究。此工作研究了不同厚度的薄膜型SiO_x负极材料的电化学性能。溅射制备SiO_x电极的Si/O比值为0.7、膜厚为450 nm时,电极初始库仑效率(ICE)为71.68%、容量保持率92.01%。以上的最优性能主要归功于电荷转移电阻低、SEI层形成减少和循环过程中电极的结构稳定性。研究表明,作为LIBs负极,控制SiO_x负极的厚度可以有效改善电极材料的电化学性能。

SiOx anodes of lithium ion batteries have attracted considerable attention in recent years, due to their cycle stability, large capacity, and feasibility on composition manipulation. Many previous works have focused on clarifying the influences of oxygen contents on SiOx based anodes. However, the size effect is still far from understanding. Herein, the size effect on electrochemical properties of SiOx with thin-film type anodes in different thickness was investigated. It is found that the SiOx electrodes prepared by sputtering is of a Si/O ratio of 0.7 and exhibits the highest initial Coulombic efficiency （ICE） of 71.68% and the highest capacity retention of 92.01% when the film thickness being 450 nm, compared with those in other thickness. The best performance under such intriguing thick- ness-performance relationship is attributed to the low charge transfer resistance, formation of the reduced SEI layer and good electrode integrity upon cycling, as evidenced by SEM images and EIS collected during cycling. These results indicate that as anodes of LIBs, the SiOx anodes with controlled size can greatly improve the electrochemical performance.