高比容量富锂层状正极材料的制备与性质研究

发布时间：2018-03-04 00:37

本文选题：锂离子电池　切入点：富锂层状正极材料　出处：《吉林大学》2014年博士论文　论文类型：学位论文

【摘要】：富锂层状正极材料具有比能量高、无毒环保、价格低廉、安全性高等优点，是具有重要应用前景的新一代锂离子电池正极材料。虽然近年来针对富锂层状正极材料的合成、结构与电化学性质研究取得了一些重要进展，然而，针对材料在电解液中的老化机制及其对材料电化学性质的影响、以及充放电过程中材料的结构变化与电化学动力学性质之间的关系尚缺乏深入细致的研究。本论文针对富锂层状正极材料存在的上述问题开展了研究。首先，利用溶胶-凝胶法合成了具有亚微米尺寸的富锂层状正极材料，并研究了材料在不同温度下的电化学性质。随后，采用在位同步辐射X射线衍射，，配合电化学分析方法，研究了富锂层状正极材料在首次充电过程中的结构变化与其电化学动力学性质之间的关系。然后，研究了富锂层状正极材料在电解液中老化（aging）之后其晶体结构、表面结构与电化学性质的变化规律。最后，针对富锂层状正极材料电导率低的缺点，制备了多壁碳纳米管（MWCNT）与富锂层状材料复合的正极材料，确定了MWCNT的最佳复合量，提高了富锂层状正极材料的电导率，进而改善了材料的电化学性能。通过本文研究，使我们加深了对富锂层状正极材料的合成、结构与电化学性质的理解与认识，为这类材料在锂离子电池中的应用提供了必要的理论依据和可行的解决方案。
[Abstract]:Li rich layered cathode materials with high specific energy, non-toxic environmental protection, low price, high security, is has important application prospect in a new generation of cathode material for lithium ion batteries. Although the synthesis of Li rich layered cathode materials in recent years, has made some important progress on the structure and electrochemical properties. However, the aging mechanism the material in the electrolyte and its effect on the electrochemical properties of materials, the relationship between structural change and electrochemical kinetics of materials and the charge and discharge process is still a lack of in-depth and meticulous research. This paper studied the problems of Li rich layered cathode materials. Firstly, the layered Li rich cathode materials with submicron size was prepared by the sol-gel method, and studied the electrochemical properties of materials at different temperatures. Then, by in-situ synchrotron radiation X ray diffraction, with The electrochemical analysis method, studied the relationship between the Li rich layered cathode materials between the first charge structure changes in the process of its electrochemical kinetic properties. Then, on the aging of Li rich layered cathode materials in electrolyte (aging) after the changes of crystal structure, surface structure and electrochemical properties. Finally, the conductivity of layered materials li rich low, multi walled carbon nanotubes (MWCNT) were prepared with the composite cathode materials of Li rich layered materials, the optimum amount of MWCNT composite, improve the conductivity of layered cathode material of lithium rich rate, thereby improving the electrochemical performance of the material. Through this study, we enhance the synthesis of layered Li rich cathode materials, understanding the structure and electrochemical properties, provide the necessary theoretical basis and feasible solution for the application of these materials in lithium ion batteries.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM912

【共引文献】