FTIR spectroscopy of metal oxide insertion materials: Analysis of LixMn2O4 spinel electrodes

Fourier transform infrared (FTIR) spectra were obtained from spinel-type lithium manganese oxides of composition Li_xMn₂O₄ with 0 < x < 2.4, prepared by both chemical and electrochemical means. Each phase in this system has a distinct spectrum which is characteristic of the local (shortrange) structure. Mixtures of phases were analyzed using the method of scaled absorbance subtraction. The results correlate well with previously reported XRD and neutron diffraction analyses as well as with phase behavior indicated by electrochemical measurements. FTIR spectroscopy thus provides both qualitative and quantitative information and is shown to be an effective companion technique to X-ray diffraction.