Abstract: 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 Li₂MnO₃, the lithium removal process of Li₂MnO₃ is studied from an energetic point of view. In LiMO₂ (M=Co, Ni) and Li₂MnO₃ 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 LiNiO₂ system is much smaller than that of LiCoO₂ and thus LiNiO₂ is supposed to show batter conductivity performance. In the process of Li⁺ removal from Li₂MnO₃, it happens in the lithium layer at the beginning of charging process, and further removal is likely to take place at the Mn_2/3Li_1/3 layer. The electric structure of the Li_xMnO₃ indicates that the charge compensation associated with lithium removal is performed mainly by the oxidation of oxygen, with only a small part of Mn oxidation.

Key words: manganese based Li-rich solid solution, first principle calculation, average potential, electronic structure

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。

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