Analysis of Electrochemical Lithium Topochemical Reactions into Superstructure Spinel Oxides

点击翻译按钮获取中文摘要

LiMn_2O_4 based spinel type oxides are one of the most promising cathode materials used in lithium ion batteries because their low cost, high theoretical energy density. In order to improve their cycle performance, several research groups have investigated the properties of manganese-substituted spionels of LiM_yMn_<2-y>O_4(M=Cr, Ni, Co, etc.). These spinels show a decreased capacity on the 4.1 V plateau, however improved cycle life was reported for Co, Ni, and Cr doped spinels. Furthermore, recently Co, Ni, and Cr doped spinels show reversible redox processes at potentials above 4.5 V.It is important to clarify the structural change, valency change during charge and discharge process in order to understand their electrochemical properties. In the present study, B-site doped spinels (LiM_yMn_<2-y>O_4 ; M=Cr, Ni, Co) were prepared. X-ray diffraction, X-ray absorption Fine Structure, and electrochemical studies were carried out.