Characterization of vanadium oxide and new V/Ce oxide films prepared by sol-gel process

The preparation of vanadium oxide and new mixed V/Ce oxide thin films as in tercalation compound for lithium ions (at 55 and 38 at % of V) started from aqueous inorganic precursors. Thin films were prepared via the sol-gel pro cess by dip-coating only once. Glass slides covered with SnO2:F were used a s substrates. The influence of added cerium precursors on the electrochemic al optical and structural properties of thin films was studied by cycling v oltammetry (CV), in-situ ultraviolet and visible (UV-VIS) spectroscopy, ato mic force microscopy (AFM) and IR spectroscopy The addition of CeO2 improve d the poor stability of vanadium oxide films and enhanced their ion-charge capacity up to 30 mC/cm(2). In all films the process of intercalation of li thium ions was followed by in-situ UV-VIS spectroscopy and ex-situ FT-IR sp ectroscopy performed at near-grazing incidence angle. The intercalation of Li+ ions was confirmed trough shifting of the absorbance edge in UV-VIS spe ctra and by the observed shifts of V-O-nu vibrations in the IR spectra. The surface of the films was also characterized by AFM imaging before and afte r cycling in IM LiClO4 in propylene carbonate electrolyte. (C) 1999 Acta Me tallurgica Inc.