Structural, chemical and electrochemical analyses of CuxV2O5 bronzes thin films

Vanadium pentoxide is one of the most attractive cathodic materials for use in microbatteries. However, the continuous insertion and extraction of lithium ions generate gradative losses in its intercalation capacity during the charge and discharge cycles. The insertion of metallic ions in the oxide matrix, forming bronzes of general formula MexV2O5 is an alternative to increase the electrochemical performance of V2O5. In this work, vanadium oxides and bronzes, in thin film form, were deposited by means of co-sputtering. Structural, chemical and electrochemical characterizations were realized in order to identify the cristallinity, composition, density and oxidation states of the elements in the film. The electrochemical techniques were used for analysis of the reversibility, charge capacity and determination of the diffusion coefficient for lithium ions. The main conclusion is that the addition of copper increased the specific volumetric capacity of the thin films and a better performance was attained during the charge/discharge cycles.