Optical and electrochemical properties of CeO2 thin film prepared by an alkoxide route

Transparent CeO2 thin solid films, used as ion storage layer in electrochromic devices were prepared by the sol–gel method using an alkoxide route combined with the dip-coating technique. The precursor sol was prepared from a mixture of cerium (IV) methoxyethoxide in anhydrous 2-butanol. Electrochemical Li+ intercalation/deintercalation was performed by cyclic voltammetry and the results indicate that the CeO2/LiClO4 system is electrochemically reversible. The total inserted/extracted charge of the CeO2 film was determined by chronoamperometric measurements, which showed an ion storage capacity of ∼14 mC/cm2. The solid-state diffusion of lithium ion into the CeO2 thin films was investigated by electrochemical impedance spectroscopy.