多晶储锂正极材料的循环失效微观机理

项目名称： 多晶储锂正极材料的循环失效微观机理

项目编号： No.51304248

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 矿业工程

项目作者： 韦伟峰

作者单位： 中南大学

项目金额： 25万元

中文摘要： 锂离子电池由于其能量/功率密度高、工作电压高、自放电小、无记忆效应等技术特性，在便携式电子设备、电动工具、汽车动力电源、可再生能源的静态存储等重大技术领域有着广阔的应用前景。但是，其循环寿命主要受制于多晶正极材料由于电化学冲击效应所导致的循环失效。本项目拟就多晶正极材料微结构演化与循环失效的微纳尺度力学机制这一关键科学问题，结合电化学性能测试、原位透射电镜研究与纳米力学测试分析，主要研究多晶储锂正极材料在不同的电化学循环状态（尤其是在高倍率充放电状态下），多相界面微结构演化及循环失效的微观机制，筛选出材料类型-显微组织-循环状态的优化判据，为获取长循环寿命锂离子正极材料提供理性设计原则。

中文关键词： 富锂层状正极材料；硅酸盐正极材料；固态复合电解质；表面微结构；电化学循环

英文摘要： Li-ion Batteries, characteristic of high energy density, high voltage, low leakage current and no memory effects, are a versatile solution to a variety of emerging applications such as portable electronics, pure electric or hybrid electric vehicles and stationary storage systems. However, Li-ion batteries experience significant capacity fading owing to electrochemical shock occurred to polycrystalline positive electrodes. Inspired by this consideration, this proposed research intends to answer the fundamental question related to the long-term cyclability of polycrystalline positive electrode materials: how the microstructure of the composite interfaces evolves irreversibly and what is the corresponding capacity fading mechanism? In this research, in-depth study on microstructural evolution of the composite interfaces during charge-discharge cycling will be carried out via in-situ TEM and nanoindetation techniques. The objectives of this proposed research are to establish the relationship between physicochemical feature evolution in polycrystalline positive electrode materials and corresponding electrochemical response during charge-discharge cycles, and to understand the capacity fading mechanism of electrode materials on atomic scale. It is anticipated that the experimental results can establish a firm basis to

英文关键词： Li-rich Layered Oxide Cathodes；Orthosilicate cathodes；Solid composite electrolytes；Surface structures；Electrochemical Cyclability