The conducting properties of room-temperature sputtered amorphous oxide films were investigated by using the galvanostatic intermittent titration technique, impedance spectroscopy and isothermal transient ionic current measurements. There was a negligible intercalation in the potential window used in WO3-based electrochromic devices. In this potential region, the Li chemical diffusion coefficient was larger than the corresponding quantity for WO3. There was a non-zero electronic conductivity, in these films, which had not been observed in chemical vapor deposited samples. Nevertheless, the ionic conductivity was about an order of magnitude larger than the electronic one.

Li Conduction in Sputtered Amorphous Ta2O5. G.Frenning, F.Engelmark, G.A.Niklasson, M.Stromme: Journal of the Electrochemical Society, 2001, 148[5], A418-21