Electrochemical properties of V2O5 thin films deposited by spin coating

The electrochemical properties of V2O5 thin films prepared by spin coating on indium tin oxide coated glass substrates using metalorganic, organic and inorganic sol–gel precursors have been investigated. The stoichiometry of the films was found to depend on the carbon to vanadium ratio in the precursors with a larger carbon content leading to a higher non-stoichiometry. The structural properties of the films were investigated by X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), Raman and UV–vis spectroscopy. The non-stoichiometry of the films was investigated by measuring the red shift in the shortest VO bond vibrational frequency between vanadium and terminal oxygen, which is consistent with the observation of planar defects in HRTEM-micrographs. The electrochemical studies by cyclic voltametry indicate that the Li+ intercalation capacity and Li+ diffusion coefficient are increased by an order of magnitude in the non-stoichiometric film, which may significantly improve the properties of vanadium oxide films as a cathode material for Li-ion batteries.