Thin crystalline films of the oxide were deposited, by reactive radio-frequency magnetron sputtering, from a metallic V target in Ar-O gas mixtures at a substrate temperature of 300C. It was found that the orientation of the films could be controlled by changing the O flow ratio. Cyclic voltammetry measurements of the films revealed that Li diffused much faster in a-axis oriented films than in b-axis oriented ones. The surface morphologies of the samples were studied, but there was little difference between them. That is, Li-ion diffusion was not dominated by the porosity of the film. It was also found that the chemical diffusion coefficient of Li along the a-axis was larger than that along the b-axis.

Electrochemical Evaluation of Oriented Vanadium Oxide Films Deposited by Reactive rf Magnetron Sputtering. H.Miyazaki, H.Sakamura, M.Kamei, I.Yasui: Solid State Ionics, 1999, 122[1-4], 223-9