摘要
富锂层状氧化物(lithium-rich layered oxide,LLO)正极材料,如Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2),具有Li_(2)MnO_(3),LiTMO_(2)(TM=Ni,Co,Mn)两相复合结构,从分子轨道理论角度分析,Li_(2)MnO_(3)中特殊的Li-O-Li构型通过O_(2p)非键合轨道激活晶格氧,发生氧化还原反应(lattice oxygen redox,LOR),使Li_(2)MnO_(3)在高压(U>4.5 V)下通过特殊的LOR提供额外的比容量.目前该材料在使用过程中存在首周库仑效率低、倍率性能差及循环中电压持续衰减等问题.电压衰减问题会导致LLO的能量密度不断降低,给电动汽车电池管理系统的应用带来困难,是LLO未能商业化的最大阻碍.对LLO的结构和机理进行综述,聚焦其电压衰减问题,讨论可能的解决办法并指出未来的研究重点,可为LLO的未来设计研究提供一定的参考.
Lithium-rich layered oxide(LLO)cathodes,such as Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2),feature a composite structure of Li_(2)MnO_(3)and LiTMO_(2)phases.From the perspective of molecular orbital theory,the unique Li-OLi configuration in Li_(2)MnO_(3)phase activates lattice oxygen redox(LOR)through O_(2p)non-bonding orbitals,providing additional specific capacity from the Li_(2)MnO_(3)phase under high voltage(>4.5 V)via this special LOR.However,the material faces several challenged that hinder its commercialization,including low initial Coulomb efficiency,poor rate performance,and continuous voltage decay during cycling.The issue of voltage decay can lead to a persistent decrease in the energy density of LLO,posing difficulties for the application of electric vehicle battery management systems and presenting the greatest obstacle to the commercialization of LLO.This manuscript reviews the structure and mechanisms of LLO,focusing on its voltage decay,discussing possible solutions,and highlighting future research priorities,thereby providing valuable insights for the future design of LLO.
作者
赵国龙
刘开心
谭永涛
崔永建
王海龙
Zhao Guolong;Liu Kaixin;Tan Yongtao;Cui Yongjian;Wang Hailong(School of Materials and New Energy,Ningxia University,Yinchuan 750021,China)
出处
《宁夏大学学报（自然科学版）》
CAS
2024年第4期426-435,共10页
Journal of Ningxia University(Natural Science Edition)
基金
国家自然科学基金面上资助项目(22379076)。
