锂离子二次电池界面反应主要包括锂离子嵌入/脱出、溶剂化/去溶剂化、电解液分解和固体电解质界面膜的形成与变化等。这些过程直接影响锂离子二次电池能源转换和储存的效率以及安全性能。运用红外光谱从分子水平上认识锂离子二次电池的各种界面反应过程并阐述其反应机理,有助于设计锂离子二次电池新体系、提升其性能并发展非水电解质理论。本文综述了锂离子二次电池界面过程的红外光谱(FTIRS)研究的最新进展,重点阐述锂离子二次电池研究中非原位红外光谱、原位红外反射光谱和原位红外透射光谱方法的建立及其对界面反应的分析。
Lithium-ion batteries (LIBs) are one of the important electrochemical power sources for low-or zero-emission hybrid electrical and electrical vehicles, energy-efficient cargo ships and locomotives, and aerospace in the modern society. The difficulties in mastering the electrode/electrolyte interface have slowed down the progress of LIBs. Interfacial processes of lithium ion batteries include mainly insertion/extraction of lithium ion, solvation/desolvation of lithium with solvents, formation and variation of solid electrolyte interphase (SEI) layer, and decomposition of electrolyte. Interracial processes directly affect the efficiency of electrochemical energy conversion and storage, such as the cycling ability, the lifetime and the reversible capacity, as well as the safety issue of lithium ion batteries. The characterization of the interface processes at a molecular level by FTIR spectroscopy is one of the key subjects, as it is helpful for the improvement the performance of lithium ion batteries and development of non-aqueous theory. Recent progresses about the application of FTIR spectroscopy in lithium ion batteries are reviewed. This review put emphasis on: (a) the characterization of chemical composition and variation of SEI layer on cycled or aged electrode materials by ex situ FTIR spectroscopy, and (b) the investigation of decomposition of electrolyte, formation of SEI layer and the insertion/extraction of lithium ion by both in-situ FTIR reflection spectroscopy and in situ FTIR transmission spectroscopy.