硅酸盐材料Li2MSiO4(M=Fe, Mn, Co, Ni)是一种新型高电压、高容量锂离子电池正极材料，但存在可逆性能差、结构不稳定等缺陷。申请人前期的研究发现Li2CoSiO4的3D结构在电化学循环过程中没有出现电压降，这在Li2MSiO4(M=Fe, Mn)中是不存在的。本项目以第一性原理计算为主要手段，确定影响Li2CoSiO4电化学特性的关键微观因素。在此基础上提出以Pmn21-DP晶相为初始模板的Co与其它过渡金属固溶的新型硅酸盐材料，以提高其电化学特性。基于通用的“理性固溶设计方案”，结合实验手段，研究阳离子混排随过渡金属配比变化的规律，揭示阳离子混排的根源；对比分析每种配比下的电子结构，揭示过渡金属间d-d相互作用与其电化学性能之间的关系。最终确定硅酸盐固溶体金属间协同效应与其电化学特性之间的微观物理机理，为其在硅酸盐固溶材料或其它类型复合电极材料中的应用奠定基础。

As novel cathode materials, silicate materials Li2MSiO4(M=Fe, Mn, Co, Ni) promise high voltage and high capacity for lithium ion battery, but they suffer poor reversibility, low-rate performance and structural instability simultaneously. The applicant found Co-silicate 3D polymorphs did not present voltage degradation as always did Fe- and Mn-silicates by the previous research on Li2CoSiO4. Therefore, this project, mainly by using first-principles calculations, aims to determinate the key factors on its electrochemical characteristics. Based on the above results, The novel solid solution of Co with other transition metals will be proposed to avoid the structural distortion by lithium ions removing, and further improve its electrochemical properties, with Li2CoSiO4 Pmn21-DP polymorph used as the starting template. Based on the universal rational design of solid solution, combined with experimental methods, systematically study the changes of cationic ordering with different ratio of transition metal to reveal the roots of cationic ordering. Comparatively analyse the electronic structure of each ratio to indicate the relationship between d-d interactions among transition metals and its electrochemical performance. Based on the foregoing work, the microscopic physical mechanisms between the synergistic effect of inter-metal in silicate solid solution and its electrochemical properties will be determined. This will lay the foundation for its application in silicate solid solution materials or other types of composite electrode materials.