The initial stages of the electrochemical intercalation of Li in sputter-deposited oxide thin films were studied. As-deposited films exhibited an appreciable and irreversible uptake of Li, without any electrochromic effect. This trapping of Li was associated with the presence of excess O in the film. The experimental results were consistent with the reaction of Li and interstitial O to form a neutral Li2-Oi complex. It was suggested that this electrochemical titration method could be used to probe excess O in other oxide films.

Lithium Trapping at Excess Oxygen in Sputter-Deposited a-WO3 Films. T.J.Vink, E.P.Boonekamp, R.G.F.A.Verbeek, Y.Tamminga: Journal of Applied Physics, 1999, 85[3], 1540-4