Evolution of the morphology,structural and thermal stability of LiCoO_(2) during overcharge  

作　　者：Zhitao E Huajun Guo Guochun Yan Jiexi Wang Rukun Feng Zhixing Wang Xinhai Li 

机构地区：[1]School of Metallurgy and Environment,Central South University,Changsha 410083,Hunan,China

出　　处：《Journal of Energy Chemistry》2021年第4期524-532,共9页能源化学（英文版）

基　　金：supported by the National Natural Science Foundation of China(51974370);the Program of Huxiang Young Talents(2019RS2002);the Innovation and Entrepreneurship Project of Hunan Province,China(Grant No.2018GK5026)。

摘　　要：The overcharge behaviors of 1000 m Ah LiCoO_(2)/graphite pouch cells are systematically investigated through the analysis of morphology,structural and thermal stability of LiCoO_(2) under different state of charge(SOC)of 120%,150%,174%,190%and 220%.The LiCoO_(2) experiences the phase transition from O3 to H1-3 and then O1 together with the grain breakage and boundary slip as evidenced by XRD and SEM analysis respectively,which results in the pronounced Co dissolution after the SOC of 174%.The impedance analysis of the pouch cells and coin cells demonstrates that the main contribution of impedance increase originates from the LiCoO_(2) electrode.Under the combined effect of structural collapse,Co dissolution,and electrolyte oxidization,the thermal stability of Li CoO_(2) cathode materials reduces with the progressing of overcharge as revealed by differential scanning calorimetry(DSC)results.We hope that this comprehensive understanding can provide meaningful guidance for advancing the overcharge performance of LiCoO_(2)/graphite pouch cells.

关 键 词：Li-ion batteries OVERCHARGE Stability LiCoO_(2) 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ131.11[化学工程—无机化工]