First-principle investigation on stability of Co-doped spinel λ-Mn_(4-x)Co_xO_8  

作　　者：黄可龙 陈春安 刘素琴 罗琼 刘志国 

机构地区：[1]College of Chemistry and Chemical Engineering, Central South University [2]Department of Chemistry and Chemical Engineering, Hunan University of Technology

出　　处：《Journal of Central South University of Technology》2007年第2期186-190,共5页中南工业大学学报（英文版）

基　　金：Project(20376086) supported by National Natural Science Foundation of China

摘　　要：The mechanism of stability of Co-doped spinel λ-MnO_2 that is referred to as spinel Li_xMn_2O_4 (x=0) was studied by using the first-principle calculation method. The total energy and formation enthalpy can be decreased remarkably due to the Co substation, resulting in a more stable structure of λ-Mn_xCr_(2-x)O_4. The bond order and DOS analysis were given in detail to explain the nature of stability improvement. The calculated results show that as the content of Co dopant increases, the bond order of Mn—O becomes larger and the peak of density of states around Fermi level shifts toward lower energy. The charge density distribution illustrates that the Mn—O bonding is ionic and partially covalent, and the covalent Mn-O bonding becomes stronger with the increase of Co dopant content. The results confirm that the Codoping will enhance the stability of λ-MnO_2 and hence improve the electrochemistry performance of Li_xMn_2O_4.The mechanism of stability of Co-doped spinel λ-MnO2 that is referred to as spinel LixMn2O4 （x=0） was studied by using the first-principle calculation method. The total energy and formation enthalpy can be decreased remarkably due to the Co substation, resulting in a more stable structure ofλ-MnxCr2-xO4. The bond order and DOS analysis were given in detail to explain the nature of stability improvement. The calculated results show that as the content of Co dopant increases, the bond order of Mn-O becomes larger and the peak of density of states around Fermi level shifts toward lower energy. The charge density distribution illustrates that the Mn-O bonding is ionic and partially covalent, and the covalent Mn-O bonding becomes stronger with the increase of Co dopant content. The results confirm that the Co-doping will enhance the stability of λ-MnO2 and hence improve the electrochemistry performance of LixMn2O4.

关 键 词：FIRST-PRINCIPLES STABILITY electrochemical performance Co-doped λ-MnO2 

分 类 号：O611.3[理学—无机化学]