高比能二次锂电池的基础研究

This project will systematically investigate the key fundamental issues in the development of advanced cathode and anode materials for next generation rechargeable lithium batteries with high specific energy, explore and summarize the electrochemical reaction mechanism and reaction rules, thus to overcome the key technology bottleneck for the future development. The topics include the exploration and investigation of novel high specific capacity cathode materials, investigation of the electrochemical reaction mechanism of the new materials and the relationship between material's structure and performance during charge/discharge process, the construction of lithium-alloy anodes with long-term cycling stability and understand the factors that affect the overall anode performance. Disclose the relationships among electrode material's composition, structure and electrochemical performance, then realization of the effectively tuning/controlling of the electrode performance. Through deeply investigating of the kinetics of electrode processes of these novel electrode materials, they will bring us to disclose electrochemical reaction mechanism in these systems and the factors that control their performances, thus it will impact the development and optimization of rechargeable lithium battery systems. The research results of this project will provide important theoretical and technical guides to the future development and research of next generation rechargeable lithium secondary batteries with self-owned intellectual property rights.

本项目拟对下一代高比能二次锂电池正、负极体系中的一些关键基础性问题开展系统研究，探索并总结其电化学反应机理及反应规律性，继而解决其核心技术的制约瓶颈问题。研究内容将包括新型高比容量正极材料体系的探索与研究，新型正极体系相关电化学反应机理及其反应过程中电极材料构效关系，长循环稳定性锂合金负极的构筑及其影响电极循环性能的诸因素等。通过阐述电极材料组成、结构及其与电化学性能的关系，进而实现对电极材料性能的有效调控。通过深入开展新电极体系的电极过程动力学研究，阐述其电化学反应机理及其控制因素，进而发展实现新型高比能二次锂电池体系。这些重要的应用基础研究将为研发具有自主知识产权的下一代高比能二次锂电池技术提供重要的理论基础和技术指导。

本项目系统深入研究了高比能二次锂电池电极及电解质材料体系、材料构效关系与电化学反应机制，包括高比容量聚阴离子型及层状氧化物和有机聚合物正极材料、高电压电解液及固态电解质、长循环稳定性锂合金负极。通过材料设计和合成方法的创新，利用多电子交换反应获得高比容量，形成了一些可以深入发展的高比能正极材料体系，如聚阴离子型磷酸铜材料利用多电子转化反应可逆比容量高达350 mAh/g；三聚喹喔啉可逆比容量达到395 mAh/g，10000次充放电循环后，容量保持率可达到70%。成功地获得了以Li-Na共沉积和共氧化为反应特征的二次电池负极，发现了有利于Li及Li-Na均匀沉积/氧化的基底材料；较为全面地解析了金属锂与不同电解质界面的特性及内在规律，在此基础上实现了优异的Li沉积/氧化循环。利用多种先进的电化学原位谱学表征技术，如电化学原位XR、XAFS、固体核磁共振谱学及成像技术，结合第一性原理计算，系统深入研究了高比能电极材料充放电过程中电化学反应机理（结构相变、局域化学环境演变、价态变化、离子输运及电荷转移机制等），深入剖析了电极材料组成-结构-电化学性能间的构效关系，为发展优化高比能二次电池提供了重要的实验依据和的理论指导。