Nanocrystalline CeO2-SiO2 thin films were spray pyrolyzed onto fluorine-doped tin oxide (FTO) coated glass substrates using a blend of equimolar concentrations of cerium nitrate hexahydrate and trimethoxymethylsilane in methanol with appropriate volumetric proportions. CeO2-SiO2 films were polycrystalline with cubic fluorite crystal structure and transforms to amorphous with increasing SiO2 content. The room temperature electrical resistivity of the film varied from 1.05 x 10(10) to 1.13 x 10(6) Omega cm with the increase in SiO2 concentration (0-6 vol% SiO2). In all cases the resistivity follows an Arrhenius behavior with negative temperature dependence in the range of 298-553 K with a thermal activation energy of 0.84 +/- 0.04 eV. Films were transparent (T similar to 80%), showing a decrease of the band gap energy (E-g) from 3.45 eV for pristine CeO2 to 3.02-3.12 eV for CeO2-SiO2 films. The ion storage capacity (ISC) and electrochemical stability of the films was affected by different morphological features of the film obtained with different CeO2-SiO2 compositions. A CeO2-SiO2 film prepared with 3 vol% Si having a thickness of 580 nm showed the highest porosity and the high ISC of 28 mC cm(-2) with an electrochemical stability of 3500 cycles in 0.5 M LiClO4+PC electrolyte. The optically passive behavior of such CeO2-SiO2 film is confirmed by its negligible transmission modulation upon Li+ ion insertion/extraction, irrespective of the extent of Li+ ion intercalation. (C) 2009 Elsevier B.V. All rights reserved.