The CeO2-TiO2-ZrO2 sol-gel film: a counter-electrode for electrochromic devices

Thin films of CeO2-TiO2-ZrO2 with 23 mol% of Ce, 45 mol% of Ti and 32 mol% of Zr were obtained by the sol-gel method. The precursor sol was prepared from a mixture of Ce(NH4)2 (NO3)6, Ti(OPri)4 and Zr(OPri)4 solubilized in isopropanol and then sonicated. Xerogels were characterized by Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) and X-ray diffraction. The films were deposited by dip-coating technique on a glass plate coated with an indium tin oxide film (ITO) and thermally treated at 80 °C for 15 min. and heated at 450 °C for 15 min in an oxygen atmosphere. By means of the addition of a lithium salt (LiCF3SO3) to the precursor solution, films with different electrochemical performances were obtained. Their possible use as ion storage (counter-electrode) in electrochromic devices (ECD) was analyzed by spectroelectrochemical measurements using cyclic voltammetry and chronoamperometry coupled to spectrometric measurements.