无钴富锂层状氧化物正极材料储锂机制的中子全散射研究

无钴锰基富锂层状氧化物正极材料因其超高的能量密度和较低的成本而备受关注。然而，钴元素的缺失使得无钴富锂材料在储锂过程中面临更严重的结构不稳定性问题。基于此，本项目提出通过Ni/Mn元素比例优化和4d过渡金属元素痕量掺杂的方法，利用不同过渡金属元素差异化的电子结构特性，调控材料的晶体结构，综合改善其电化学性能。同时，利用中子对锂、氧等轻质元素和镍、锰等近邻元素敏感的特性以及全散射技术在分析局域结构方面的独特优势，系统研究无钴富锂材料在储锂过程中的结构演化规律，确定材料化学组分对其不可逆结构演化以及储锂结构稳定性的调控作用。在制备筛选高性能无钴富锂材料的同时，为该材料体系的进一步优化设计提供理论基础和科学指导。

Due to the ultrahigh energy density and relative low cost, Co-free Mn-based Li-rich layered oxide cathode materials have received great attention. However, the absence of Co element makes Co-free Li-rich materials face the problem of more serious structure instability during the Li storage process. Based on this, a method of Ni/Mn element ratio optimization and trace doping of 4d transition metal elements was proposed in this project, and the crystal structure of materials will be regulated by the different electronic structure characteristics of different transition metal elements, so as to comprehensively improve their electrochemical performance. Meanwhile, the sensitivity of neutron to light elements, such as Li and O, and neighboring elements, such as Ni and Mn, as well as the unique advantage of total scattering in analyzing local structure will be used to systematically study the structure evolution rule of Co-free Li-rich materials during the Li storage process, and the regulating effect of chemical composition on unreversible structure evolution as well as stable Li storage structure will be understanded. While preparing and screening high-performance Co-free Li-rich materials, the research will provide theoretical basis and scientific guidance for the further optimization and design of this material system.