SPECTROSCOPIC INVESTIGATIONS OF LI-INTERCALATED V2O5 POLYCRYSTALLINE FILMS

Polycrystalline V2O5 films (0.15 mum thick) have been electrochemicall y intercalated with Li+ at constant current, so that to obtain a set o f 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 revers ible Li+ intercalation for x less-than-or-equal-to 1, in agreement wit h previous observations on pellettized V2O5 powder electrodes. Some co mpositions (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 see m to indicate a non complete recovery of the original electronic confi guration and of the structure in the material after the inserted Li+ h as been fully extracted via a reverse electrochemical reaction.