Fluorinated oxide films were prepared by reactive sputtering, and the mobilities of Li, Na, and K were studied by using electrochemical techniques. Chronopotentiometric data suggested that the cations occupied one type of site for cation/Ti ratios of less than 0.5, while other sites were populated at higher ratios. The intercalation of Li and Na appeared to proceed without major structural change, whereas the intercalation of (larger) K ions led to structural rearrangement. The impedance spectra were analyzed in terms of a Randles circuit, with a finite-length Warburg element. From this, chemical diffusion coefficients were obtained for various intercalation levels and temperatures. It was concluded that the ion diffusion could be understood in terms of the classical Anderson-Stuart model, provided that the structure remained unchanged. Consequently, K intercalation could not be explained by this model.

Diffusion of Li, Na, and K in Fluorinated Ti Dioxide Films: Applicability of the Anderson–Stuart Model. Mattsson, M.S., Niklasson, G.A., Granqvist, C.G.: Journal of Applied Physics, 1997, 81[5], 2167-72