前、后过渡金属在高电压层状结构正极材料中的协同作用机制

项目名称： 前、后过渡金属在高电压层状结构正极材料中的协同作用机制

项目编号： No.51502319

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 马君

作者单位： 中国科学院青岛生物能源与过程研究所

项目金额： 20万元

中文摘要： 层状结构正极材料在高电压充放电时较差的结构稳定性导致循环性能显著降低，使其成为高比能、长寿命锂离子电池进一步发展的瓶颈之一。本项目拟设计合成由可提供较高比容量的后过渡金属M和能够提高结构稳定性的前过渡金属M'共同组成的层状结构正极材料LiM1-xM'xO2，综合利用XRD、XAS、STEM等多种原位/非原位表征技术，从晶体结构和电子结构的角度研究其在高电压脱嵌锂时的结构演化机理，揭示结构稳定性与储锂行为的构效关系，探明前、后过渡金属在结构稳定性和储锂性能方面的协同作用机制，阐明层状结构正极材料LiM1-xM'xO2在高电压工作时前、后过渡金属协同作用、结构演化和储锂行为的规律，为设计兼顾高比容量和长循环寿命的层状结构正极材料提供理论依据。

中文关键词： 锂离子电池；正极材料；层状结构；结构转变；长循环寿命

英文摘要： High energy density and long cycle life lithium-ion battery (LIB) has been bottlenecked by the unsatisfied cycling performance of layer-structured cathode materials due to their poor structure stability at high voltage. In this proposal, layer-structured cathode material LiM1-xM'xO2 consisting of late (M) and early (M') transition metals were designed, in which M and M' can supply high capacity and structure stability, respectively. LiM1-xM'xO2 has been investigated comprehensively by in/ex situ XRD, XAS, STEM and other techniques. During high voltage lithiation/delithiation, the crystalline and electronic structure transition as well as structure active relationship will be characterized carefully. The electrochemical mechanism and synergistic effects of early and late transition metals on the structure stability of LiM1-xM'xO2 will be explored through investigating the electrochemical performance dependence on the structure evolution. This project will shed light on the design and modification of layer-structured cathode materials with both high energy density and long cycle life.

英文关键词： lithium-ion battery;cathode material;layer structure;structure transition;long cycle life