微波辅助制备富锂层状正极材料及其脱嵌锂机理的电镜学研究

项目名称： 微波辅助制备富锂层状正极材料及其脱嵌锂机理的电镜学研究

项目编号： No.21203033

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理化学

项目作者： 汪敏

作者单位： 复旦大学

项目金额： 26万元

中文摘要： 富锂层状材料是近几年快速发展的新型锂离子电池用正极材料，因比容量高和循环性能优秀获得广泛关注，其结构和脱嵌锂机理是当前研究热点。本课题计划采用微波辅助溶胶凝胶法合成一系列富锂材料xLi2MnO3o(1-x) Li(Ni1/3Co1/3Mn1/3)O2 (x=0.2，0.4，0.6)，通过电镜和X射线衍射法对其微观结构进行表征，组装实验电池测试其电化学性能，优化合成条件，获得结构规整、颗粒小且粒径均匀的富锂材料。同时借助电镜分析手段，运用电子能量损失谱、高角环行暗场像技术和高分辨成像技术等，从原子层面上研究不同循环周次下富锂材料晶体结构的变化，研究富锂材料脱嵌锂机理，阐明其容量损失机制，由此建立材料结构与电化学性能之间的关联，为新型富锂正极材料的设计和改性提供理论指导方向。

中文关键词： 锂离子电池；正极材料；材料合成；电子显微镜；微观结构

英文摘要： The Lithium-rich layered materials have emerged as promising cathode materials for lithium-ion batteries in past few years due to their high capacity, excellent cycleability, good structural stability and low cost. The distinct electrochemical properties may be associated with a new electrochemical charge-discharge mechanism different with other kind of lithium-ion cathode materials, which need to be further investigated. This project focuses on the preparation and characterization of Li-rich materials, and the study on the lithium extraction/insertion mechanism. 1. Preparing a series of lithium-rich layered materials, xLi2MnO3o(1-x) Li(Ni1/3Co1/3Mn1/3)O2 (x=0.2，0.4，0.6), via a microwave-assisted sol-gel process; Characterizing the microstructure of the as-prepared materials by X-ray photoelectron spectroscopy and transmission electron microscopy; Testing the electrochemical properties of the synthesized materials with coin cells at the room temperature. Then, the preparation conditions of microwave sintering time and temperature will be optimized in order to obtain well-ordered, small size and uniform particles. 2. Investigating the crystal structure variations for series cathode active materials after different cycle times through high resolution transmission electron microscopy (HRTEM), electron energy loss

英文关键词： Lithium-ion battery；Cathode material；Material synthesis；Electron microscopy；Micro-structure