锂离子电池硅薄膜电极充放电形态实验研究  

Experimental study on charge-discharge morphology of silicon thin film electrode for lithium-ion battery

作　　者：齐志凤 马伟皓 杨思源 王志勇[1] 李林安[1] 王世斌[1] 李传崴[1] QI Zhifeng;MA Weihao;YANG Siyuan;WANG Zhiyong;LI Linan;WANG Shibin;LI Chuanwei(Department of Mechanics,School of Mechanical Engineering,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学机械工程学院力学系,天津300350

出　　处：《实验力学》2020年第6期1041-1048,共8页Journal of Experimental Mechanics

基　　金：硅薄膜电极充放电形态和微裂纹演化机理的实验研究,国家自然科学基金项目(11602167)。

摘　　要：硅基电极材料因其比容量高、低脱锂电位和低成本等优点被认为是最具有潜力的下一代锂离子电池负极材料之一。然而,硅电极在嵌锂/脱锂过程中会产生巨大的体积膨胀,从而引起电极结构的力学损伤,使其力学和电化学性能大幅度衰减,最终影响电池寿命。因此,针对硅薄膜电极在充放电过程中的变形和损伤演化行为开展研究是非常必要的。本文采用射频磁控溅射方法沉积的非晶硅薄膜作为工作电极,以CR2032型纽扣电池为原型,设计了电极可视化纽扣电池,利用激光共聚焦显微镜(Laser Scanning Confocal Microscope,LSCM)系统,结合数字图像相关(Digital Image Correlation,DIC)方法对硅薄膜电极在嵌锂/脱锂过程中的全场变形进行在线测量。基于实验数据中电极应变场和荷电状态(State of Charge,SOC)的关联关系,分析了硅电极在充放电过程中的力电耦合效应。本文结果为进一步研究硅薄膜电极在电化学循环过程中的变形及损伤提供了实验基础,对改进和优化设计新型高性能高容量的锂离子电池具有一定意义。Silicon-based electrode materials are believed to be one of the most prospective anode materials due to their advantages including high specific capacity,low electric potential and low cost.However,the large volume expansion and the internal stress usually emerge during the lithiation/delithiation processes,leading to mechanical/electrochemical failures and ultimate life reduction of the lithium-ion battery.Therefore,it is essential to study the deformations and failure behaviors of silicon electrodes in the charge-discharge processes.In the current study,the working film electrode is manufactured with a sputtering method from silicon source.Abutton battery with an optical window on the surface based on the button cell(CR2032)for electrode visualization is specially designed.The laser scanning confocal microscopy(LSCM)and the digital image correlation(DIC)method are used to experimentally obtain the full field strain distribution in situ.Based on the correlation between the strain and the state of charging(SOC),the mechanical/electrochemical coupling effect is analyzed.The current study provides a potential way for future investigations on mechanical failures and optimizations of silicon electrodes as well as novel design for high capacity lithium-ion battery.

关 键 词：锂离子电池 硅薄膜电极 嵌锂/脱锂 数字图像相关 

分 类 号：O348.1[理学—固体力学] TM911[理学—力学]