界面化学对镍锰酸锂正极材料电化学性能影响的研究现状及分析

尖晶石LiNi_0.5Mn_1.5O₄正极材料因理论比容量和理论比能量高、工作电压高、资源丰富且价格低廉等优点而备受关注,但该材料因为高电压下电解液的分解及界面副反应导致循环性能和倍率性能不佳,制约着材料的推广应用。结合近几年的研究报道,介绍了LiNi_0.5Mn_1.5O₄正极材料的结构及脱嵌机制、表/界面化学、改性方法,着重介绍了LiNi_0.5Mn_1.5O₄材料的表面性质及不同组分之间的界面反应机制及对正极材料电化学性能的影响,指出LiNi_0.5Mn_1.5O₄材料的晶面取向、颗粒形貌、表面元素分布、包覆及离子掺杂是改善镍锰酸锂材料电化学性能的有效途径。同时,通过溶剂替代、成膜添加剂的添加、改变锂盐的种类及浓度等方式,开发与之匹配的耐高压电解液也是提升镍锰酸锂电池性能的重要方法。最后,对LiNi_0.5Mn_1.5O₄正极材料表面改性和电解液界面构筑方面进行了总结和展望,旨在为提升该材料性能的相关研究提供参考。

Research status and analysis of effect of interfacial chemistry on electrochemical properties of LiNi0.5Mn1.5O4 cathode materials

Spinel LiNi_0.5Mn_1.5O₄ cathode material has attracted much attention due to its high theoretical specific capacity,high theoretical specific energy,high working voltage,abundant resources and low price.However,its poor cycling performance and rate performance are caused by the decomposition of electrolyte and interface side reaction under high pressure,which restricts its popularization and application.Combined with the research reports in recent years,the structure and the mecha-nism of the intercalation,surface/interface chemistry,and modification methods of LiNi_0.5Mn_1.5O₄ cathode material are introdu-ced.The surface properties of LiNi_0.5Mn_1.5O₄,the interfacial reaction mechanism between different components and its influence on the electrochemical performance of cathode material are emphatically introduced.It proposes that the crystal plane orienta-tion,particle morphology,surface element distribution,coating and ion doping are effective ways to improve the electrochemi-cal performance of LiNi_0.5Mn_1.5O₄ material.At the same time,the development of suitable high-voltage electrolyte by solvent substitution,film-forming additives addition,changing the type and concentration of lithium salt is also an important method to improve the performance of LiNi_0.5Mn_1.5O₄ battery.Finally,the surface modification of LiNi_0.5Mn_1.5O₄ cathode material and the construction of electrolyte interface are summarized and prospected,which aims to provide reference for the related research on improving the performance of the material.