Thin films of CeO2 and CeO2-TiO2 having a wide range of compositions prepared following sol-gel spin coating technique involving a Ce (III) salt and titanium propoxide in ethanol fired at 500 degreesC were investigated by different characterization techniques to obtain information on thermal, structural, optical and electrochemical aspects of the films. The influence of the structure on the kinetics of electrochemical insertion/extraction of lithium ions was evaluated with the outcome of above results emphasizing the importance of TiO2 in relation to improvement of coloration-bleaching kinetics of electrochromic material configured with CeO2-TiO2 films, rendering them suitable for electrochromic windows. The XRD investigations showed the prevalence of amorphicity in the films constituting 50% or lower mole percentage Of CeO2. The compositions with higher CeO2 contents exhibited nanocrystallinity and were distinguished by the existence of diffraction peaks assigned to cerianite and the mixed compound, CeO1.6.2TiO(2). In all the compositions, presence of TiO2 in the amorphous phase was clearly evident, which led to the enhanced ion insertion capacity of the films. The highest cathodic charge density (CCD) of 23 mC/cm(2) was observed for the film containing 75% TiO2. The AFM images clearly show the reduced level of roughness and the grain size of CeO2 in the films with the increased content of TiO2. The best performance characteristics achieved for the electrochromic device comprising WO3 and 50% CeO2 electrodes conveys the practical utility of the latter in the transmissive electrochromic devices. (C) 2004 Elsevier B.V All rights reserved.