Li_2MnO_3·LiMO_2(M=Co,Ni)的电子结构与性能  

Electronic structure and properties of Li_2MnO_3·LiMO_2(M=Co,Ni) by density functional theory

作　　者：李雪[1] 谢晓峰[1] 

机构地区：[1]清华大学核能与新能源技术研究院,北京100084

出　　处：《化工学报》2013年第S1期188-193,共6页CIESC Journal

基　　金：国家高技术研究发展计划项目(2012AA052201)~~

摘　　要：将富锂锰基正极材料Li2MnO3·LiMO2(M=Co,Ni)分为LiMO2和Li2MnO3两部分,基于密度泛函理论第一性原理方法对其分别进行了研究,分析和计算了LiMO2(M=Co,Ni)的结构和性能及Li2MnO3的脱锂过程。结果表明:在LiMO2(M=Co,Ni)和Li2MnO3中锂以离子形式存在,LiNiO2体系的导电性优于LiCoO2体系,Li2MnO3在脱锂过程中锂离子首先从锂层中脱出,之后从过渡金属层进一步脱锂,其中锂脱出造成的电荷变化主要由O的氧化来补偿。A systematic first principles calculation based on density functional theory is carried out to discuss the structures and properties of LiMO2(M=Co,Ni)and Li2 MnO3,the lithium removal process of Li2 MnO3 is studied from an energetic point of view.In LiMO2(M=Co,Ni)and Li2 MnO3 crystal structures,lithium exists in the Li+form,and transition metals(Co,Ni,Mn)are covalently bound to O. Because of spin polarization,the energy band gap of LiNiO2system is much smaller than that of LiCoO2 and thus LiNiO2 is supposed to show batter conductivity performance.In the process of Li+removal from Li2 MnO3,it happens in the lithium layer at the beginning of charging process,and further removal is likely to take place at the Mn2/3Li1/3layer.The electric structure of the LixMnO3indicates that the charge compensation associated with lithium removal is performed mainly by the oxidation of oxygen,with only a small part of Mn oxidation.

关 键 词：富锂锰基固溶体 第一性原理 平均嵌锂电势 电子结构 

分 类 号：O611.3[理学—无机化学]