New Structural Characterization of the Li_xV₂O₅ System Provided by Raman Spectroscopy

The Raman spectra of the ε-, δ-, and γ-Li x V 2 O 5 powdered phases are reported. New fingerprints are obtained and discussed in connection with those previously reported for electrochemically and chemically lithiated V 2 O 5 . The metastable character of the δ-phase is explored through the XRD and Raman study of the δ → ε → γ “high temperature” phase transitions and allows explaining the great disparities encountered in the literature spectra. The knowledge of these reference Raman spectra for the Li x V 2 O 5 phases constitutes fundamental data for understanding the electrochemical cycling behavior of the Li/V 2 O 5 system.