摘要
以LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)/硅-石墨(Si-C)软包装电池作为研究对象,通过平均电压、d Q/d U曲线、SEM、透射电子显微镜(TEM)、XRD和X射线能谱仪(EDS)等方法,研究软包装电池常温循环失效的原因。NCM622/Si-C软包装电池以1 C在3.0~4.3 V循环300次,容量保持率为79.1%,循环过程中电池整体厚度逐渐增大,全荷电态下循环300次,厚度较循环前增加11.25%,主要由负极膨胀引起。在循环过程中,NCM622正极材料晶体结构保持完整,但有活性物质颗粒出现微裂纹;Si-C负极嵌锂膨胀、脱锂收缩,使硅颗粒破碎,负极材料表面固体电解质相界面(SEI)膜不断修复生长,从而消耗可逆的活性锂,这是电池循环容量衰减的主要原因。
With LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)/silicon(Si)-graphite(C)pouch battery as the research object,the failure reasons of the battery at room temperature cycle were studied by means of average voltage method,d Q/d U curves,SEM,transmission electron microscope(TEM),XRD and X-ray energy disperse spectroscopy(EDS).The capacity retention rate of the NCM622/Si-C pouch battery was 79.1%at 1 C in 3.0-4.3 V after cycled 300 times.During the cycles,the overall thickness of the battery gradually increased.After cycled 300 times,the thickness of the battery in the fully charged state increased by 11.25%compared with that before cycled,was mainly caused by the expansion of negative electrode.During the cycling process,the structure of NCM622 anode material remained intact,but there were microcracks in the active substance particles;the silicon particles were broken due to the expansion and shrinkage of Si-C anode,and the solid electrolyte interface(SEI)film on the anode surface kept repairing and growing,thus consumption of reversible active lithium,which was the main reason for the decline of cycling capacity of battery.
作者
郑舒
李保鹏
常艳
蔡洪波
ZHENG Shu;LI Bao-peng;CHANG Yan;CAI Hong-bo(School of Material Sciences and Engineering,Henan Institute of Technology,Xinxiang,Henan 453003,China;Henan Lithium Power Source Co.,Ltd.,Xinxiang,Henan 453000,China)
出处
《电池》
CAS
北大核心
2021年第2期173-177,共5页
Battery Bimonthly
基金
河南省高等学校重点科研项目计划基础研究专项(21A480004)
河南省科技攻关项目(192102310499)。
