Mg,Al掺杂对LiCoO2体系电子结构影响的第一原理研究

为了研究Mg ,Al掺杂对锂二次电池正极材料LiCoO2 体系的电子结构的影响 ,进而揭示Mg掺杂的LiCoO2 具有高电导率的机理 ,对Li(Co ,Al)O2 和Li(Co,Mg)O2 进行了基于密度泛函理论的第一原理研究 .通过对能带及态密度的分析 ,发现在Mg掺杂后价带出现电子态空穴 ,提高了电导 ,并且通过歧化效应 (disproportionation)改变了Co 3d电子在各能级的分布 ,而Al掺杂则没有这些作用 .O2 - 的离子性在掺杂后明显增强 .

Ab initio study of the effects of Mg, Al doping on the electronic structure of LiCoO2

In order to investigate the effect of Mg, Al doping on the electronic structure of LiCoO 2, and to find the mechanism of high electronic conductivity in Mg-doped LiCoO 2, we have carried out first-principles calculations based on density-functional theory (DFT) for LiCoO 2, Li(Co, Al)O 2 and Li(Co, Mg)O 2 systems. Studies of band structures and densities of states show that hole states, which enhance the conductivity of semiconductor, appear in the valence bands of Mg-doped material, and the effect of charge disproportionation changes the distribution of Co-3d states in different energy levels. The ionicity of O 2- increases with Mg and Al doping.