锂离子电池用新型电解质锂盐LiBSO4F2与LiBSO3F2的制备及应用电化学性能研究

The commercial lithium-ion batteries containing LiPF6-based electrolytes have given rise to certain drawbacks, for its limited thermal stability and high sensitivity to trace moisture in the air. The development of a novel conducting salts for electrolyte is of great importance for battery applications. Based on the experimental prediction and our theoretical calculation, this proposal aims to synthesize LiBSO4F2 and LiBSO3F2 salts with excellent properties for the first time. Effects of functional groups within salt molecules and electrolyte solvents on performances of lithium-ion batteries as well as compatible mechanisms of electrolytes with anode materials will be discussed by studying of properties (e.g., the formation processes, compositions and surface morphologies) for solid electrolyte interface layers. Besides, the compatibilities of prospecting electrolytes with various cathode materials will also be discussed by studying of the dissolution of electrolytes for cathode materials, safety in heating, and the performance of assembled cells. Effects of structures on performances of conducting salts and correlations between structures of conducting salts and compositions of electrolytes will be clarified with the reseach going on. In addition, it is possible that the implementation of this proposed project will not only build correlations and relational models among structures of conducting salts, suitable electrolyte compositions, interfacial properties and cell’s performances, but also provide a useful theoretical guidance for design, formulation and optimization of new salts and electrolytes for lithium-ion batteries in the future.

传统电解质LiPF6盐具有较为优异的综合性能，但其热稳定性较差且易潮解。因此，寻找新型锂盐是电池领域的一个研究重点。在经验预测及理论计算的指导下，项目试图制备出综合性能优异的LiBSO4F2、LiBSO3F2产品。以基于新盐的电解液组装试验电池，通过系统研究固体电解质界面膜的形成过程、组成、形貌等性质，充分明确锂盐中各种官能团、电解液体系中各种溶剂在电池体系中实际发挥的作用及其与负极材料的相容机理。通过系统研究新型电解液对正极材料的溶蚀、热安全性问题及所组装电池的综合性能，深入探讨新型电解液体系与不同正极材料的相容性能及其机理。通过研究，明确锂盐结构对锂盐性能的影响，总结出锂盐结构与适宜电解液组成间的关系，明确电解液组成对界面性质及电池各项性能的影响，建立起锂盐结构-适宜电解液组成-界面性质-电池综合性能四者间具有普遍指导意义的关联模型，进而为新盐及电解液配方的研发提供理论支持与指导。

目前传统锂盐已不能完全满足人们对于锂离子电池性能的要求，研究者需寻找新型锂盐来进一步提高电池性能。本项目利用锂盐结构特性制备出了综合性能优异的锂盐LiBSO4F2和LiBSO3F2。并通过该新盐电解液体系与量子化学计算结合得到该锂盐还原过程及固体电解质界面膜的形成过程、组成、形貌等性质。探讨了锂盐中各种官能团、电解液体系中各种溶剂在电池体系中实际发挥的作用，明确锂盐结构与适宜电解液组成间的关系。并通过研究新型电解液体系适配于不同电极材料具有优异的电化学性能，建立起锂盐结构-适宜电解液组成-界面性质-电池综合性能四者间具有普遍指导意义的关联模型，进而为新盐及电解液配方的研发提供理论支持与指导。