【摘要】 基于密度泛函理论的第一原理赝势法 ,研究了Mg在Li(Co ,Al)O2 中掺杂前后的电子结构的变化 .通过能带和态密度的分析 ,发现Mg掺杂后在价带中引入了电子空穴 ,同时价带展宽 ,这两个电子结构的显著变化是引起Li(Co ,Al)O2 导电率提高的主要机理 .通过对Co3d电子态密度的分析发现 ,在二价Mg掺杂后 ,Li(Co ,Al)O2 中的Co价态升高 ,介于Co3+和Co4 +之间 .从能带计算出发 ,进一步定量给出了Co和O的平均价态的变化 .更多还原

【Abstract】 Electronic structures of Li(Co,Al)O 2 and Mg-doped Li(Co,Al)O 2 were studied theoretically via ab initio calculation based on density-functional theory. Studies of band structures and density of states show that hole states appear in the valence bands of the Mg-doped material as well as an increase in bandwidth,which are in charge of the increase in the observed electronic conductivity. It was found by analysis of Co3d density of states that the divalence Mg doping induces a higher cobalt valence state between Co \{3+\} and Co \{4+\} in Li(Co, Al,Mg)O 2,which is in good agreement with experimental results. Using the band theory,we have calculated the average valence states of Co and O.更多还原