锂电池正极材料Li(Co,Ni)O_2化合物的第一性原理研究

First-principles study of the cathode materials-Li(Co,Ni)O_2 compounds

锂离子电池以其高能量存储密度和优良的循环性能而受到广泛关注,尤其是其正极材料成为储能材料领域的研究热点.本文采用基于密度泛函理论的第一性原理方法对LiCoO_2,LiNiO_2和Li(Co_(0.5)Ni_(0.5))O_2化合物的晶体结构、电子结构、化学键合特性进行了研究.结果表明:Li(Co_(0.5)Ni_(0.5))O_2化合物中主要是氧和过渡金属之间成键,锂原子对晶体总态密度贡献很少.Ni/Co混合后将导致Li(Co_(0.5)Ni_(0.5))O_2中Co的3d轨道和O的2p轨道之间成键得以加强.

Recently, Layered transition-metal oxides, Li（Co, Ni）O2, have been considered as potential cathode materials for lithium batteries with high energy storage density and excellent cycle performance. The crystal structures, electronic properties and chemical bonding properties of LiCoO2, LiNiO2, and Li （Co0.5 Ni0.5）O2 have been studied using density functional theory （DFT） and plane-wave pseudopotential technique. The results indicate that the bonds in Li（Co, Ni）O2 compounds are due mainly to oxygentransition metal, the contribution of lithium ion to the total density of crystals is small; and when mixed with Nis＋ , the band of Co3d-O2p in Li（Co0. sNi0.5O2）compound becomes stronger.