Fourier-transform infrared spectroscopic studies on the solid electrolyte interphase formed on Li-doped spinel Li 1.05Mn 1.96O 4 cathode

Abstract

Fourier-transform infrared (FTIR) spectroscopy has been used to identify the solid electrolyte interphase (SEI) formed on Li-doped spinel Li 1.05Mn 1.96O 4 cathode. The major components in the SEI have been assigned, and the formation and evolution of the SEI over the initial charge–discharge cycle are discussed. By Fourier-transform infrared spectroscopy, it has been found that during the charge–discharge process, the SEI can be directly formed on the Li 1.05Mn 1.96O 4 cathode, and is mainly composed of R-CO 3Li and Li 2CO 3. In terms of composition, it is very similar to those formed on a carbon anode. In the initial cycle, the formation of R-CO 3Li begins at 4.10 V during the charging process, and becomes more distinct with increasing charge voltage. The formation of Li 2CO 3 begins at 4.10 V during the discharge process, and becomes more distinct with decreasing discharge voltage. The SEI becomes more evident over subsequent cycles.