Ex situ FTIR spectroscopy study of LiVPO4F as cathode material for lithium-ion batteries

The LiVPO₄F as cathode material for lithium-ion batteries was synthesized through two steps of solid-state reactions and investigated by ex situ Fourier transform infrared (FTIR) spectroscopy for the initial charge and discharge cycle. The characterization of the effect on the structure of the LiVPO₄F in the process of lithium-ion insertion/extraction at a molecular level by ex situ FTIR spectroscopy is helpful for the mechanism research for lithium-ion insertion/extraction and the improvement of the performance of lithium-ion batteries. In the process of the initial cycle, new bands of VPO₄F appear in the charge and the featured bands of LiVPO₄F reappear in the discharge. In this paper, ex situ FTIR spectra indicates that the structure of the LiVPO₄F in the process of lithium-ion insertion/extraction is almost not affected, which clearly states that the LiVPO₄F possesses stable structure as cathode material. Consequently, the LiVPO₄F might be expected as a potential cathode replacement for commercial lithium-ion batteries.