SPECTROSCOPIC INVESTIGATIONS OF LI-INTERCALATED V2O5 POLYCRYSTALLINE FILMS

Polycrystalline V2O5 films (0.15 mum thick) have been electrochemically intercalated with Li+ at constant current, so that to obtain a set of different cation concentrations. The open circuit potential and the optical transmittance of the LixV2O5 films were followed as a function of the lithium charge. The electrochemical measurements show a reversible Li+ intercalation for x less-than-or-equal-to 1, in agreement with previous observations on pellettised V2O5 powder electrodes. Some compositions (x congruent-to 0, 0.3, 1) have been also characterized by both optical absorbtion and micro-Raman spectroscopy, which appear to be very sensitive to the Li+ content. Raman and absorbtion spectra seem to indicate a non complete recovery of the original electronic configuration and of the structure in the material after the inserted Li+ has been fully extracted via a reverse electrochemical reaction