锂离子电池正极材料Li_xNi_(0.5)Mn_(0.5)O_2电子结构的第一性原理研究  

First principles study on electronic structure of Li_xNi_(0.5)Mn_(0.5)O_2 cathode material for lithium ion batteries

作　　者：罗垂意 李之锋[1,2] 彭弯弯 钟盛文[1,2] 郭进康 赖江洪 吕庆文[1,2] 

机构地区：[1]江西理工大学材料科学与工程学院,江西赣州341000 [2]江西省动力电池及其材料重点实验室,江西赣州341000

出　　处：《有色金属科学与工程》2016年第4期45-49,共5页Nonferrous Metals Science and Engineering

基　　金：国家自然科学基金资助项目(51372104);江西省对外科技合作项目(20123BDH80016)

摘　　要：采用基于密度泛函理论的第一性原理超软赝势平面波法,对Li_xNi_(0.5)Mn_(0.5)O_2的几何结构进行优化,并计算相应的电子结构和平均嵌锂电压.结果表明:x=1时,费米能级上分布着Ni、Mn d轨道电子和部分O2p轨道电子,层状LiNi_(0.5)Mn_(0.5)O_2是电子的良导体;O2p轨道与Ni、Mn形成较强的共价键,Ni-O与Mn-O具有相近的键长,抑制了LiNiO_2与m-LiMnO_2中的因Jahn-Teller效应导致的八面体扭曲,且Mn-O键长在充放电过程中保持不变,材料具有稳定的结构;Li在晶胞中以主要离子态的形式存在,有利于脱嵌与传输.随着锂离子的脱出,材料的带隙增加,导电性能变差.The geometries of LixNi0.5Mn0.5O2 was optimized by density functional theory （DFT） plane-wave uhrasoft-pseudopotential method, and then the corresponding electronic structure and average intercalation-Li voltage were calculated. The results indicate that when x=1, the d orbital electron of Ni, Mn and part of O2p near the fermi surface are electronic contributors; O2p and Ni （Mn） 3d orbials form strong covalent bonds. The bond length of Ni-O is similar to that of Mn-O, which inhibits the distorting of M-O octahedron. LiNi0.5Mn0.5O2 is not only a good electric conductor but also owns stable structure. Li exists in layer material mainly in the state of Li＋, which is conducive to deintercalation and diffusion. The electrical conductivity gradually becomes poor with the deintercalation of Li-ion and the increase of band gap.

关 键 词：LINI0.5MN0.5O2 平均嵌锂电压 态密度 电子结构 能带结构 

分 类 号：TM911[电气工程—电力电子与电力传动]