Effect of crystal morphology of ultrahigh-nickel cathode materials on high temperature electrochemical stability of lithium ion batteries  

作　　者：Bi Luo Hui Li Haoyu Qi Yun Liu Chuanbo Zheng Weitong Du Jiafeng Zhang Lai Chen 

机构地区：[1]School of Metallurgy Engineering,Jiangsu University of Science and Technology,Zhangjiagang 215600,Jiangsu,China [2]National Engineering Laboratory for High-Efficiency Recovery of Refractory Nonferrous Metals,School of Metallurgy and Environment,Central South University,Changsha 410083,Hunan,China [3]School of Materials Science and Engineering,Beijing Key Laboratory of Environmental Science and Engineering,Beijing Institute of Technology,Beijing 100081,China

出　　处：《Journal of Energy Chemistry》2024年第1期327-335,I0008,共10页能源化学（英文版）

基　　金：supported by the Natural Science Foundation of Jiangsu Province (BK20210887);the Jiangsu Provincial Double Innovation Program (JSSCB20210984);the Natural Science Fund for Colleges and Universities of Jiangsu Province (21KJB450003);the Jiangsu University of Science and Technology Doctoral Research Start-up Fund (120200012)。

摘　　要：Higher nickel content endows Ni-rich cathode materials LiNi_(x)Co_yMn_(1-x-y)O_(2)(x>0.6)with higher specific capacity and high energy density,which is regarded as the most promising cathode materials for Li-ion batteries.However,the deterioration of structural stability hinders its practical application,especially under harsh working conditions such as high-temperature cycling.Given these circumstances,it becomes particularly critical to clarify the impact of the crystal morphology on the structure and high-temperature performance as for the ultrahigh-nickel cathodes.Herein,we conducted a comprehensive comparison in terms of microstructure,high-temperature long-cycle phase evolution,and high-temperature electrochemical stability,revealing the differences and the working mechanisms among polycrystalline(PC),single-crystalline(SC)and Al doped SC ultrahigh-nickel materials.The results show that the PC sample suffers a severe irreversible phase transition along with the appearance of microcracks,resulting a serious decay of both average voltage and the energy density.While the Al doped SC sample exhibits superior cycling stability with intact layered structure.In-situ XRD and intraparticle structural evolution characterization reveal that Al doping can significantly alleviate the irreversible phase transition,thus inhibiting microcracks generation and enabling enhanced structure.Specifically,it exhibits excellent cycling performance in pouch-type full-cell with a high capacity retention of 91.8%after 500 cycles at 55℃.This work promotes the fundamental understanding on the correlation between the crystalline morphology and high-temperature electrochemical stability and provides a guide for optimization the Ni-rich cathode materials.

关 键 词：SINGLE-CRYSTALLINE Ultrahigh-nickel cathode High-temperature performance Phase evolution 

分 类 号：TM912[电气工程—电力电子与电力传动]