A highly (003)-oriented pure LiCoO2 thin film cathode, without Co3O4 impurities, was grown onto a stainless steel substrate by pulsed laser deposition, and was characterized by means of electrochemical testing, scanning electron microscopy, ex situ X-ray diffraction, Raman and X-ray photo-electron spectroscopy. The chemical diffusion coefficient of the Li+ ion was estimated to be about 4.7 x 10−11cm2/s, from cyclic voltammetry scans. Ex situ X-ray diffraction revealed that the spacing of crystalline planes expanded by about 0.09Å when charged to 4.2V; corresponding to Li0.5CoO2. This was lower than the value for composite powder LiCoO2 electrodes. The photo-electron spectroscopy results showed that the number of low-coordination O ions increased relative to the removal of Li+ ions.

Characterization of a LiCoO2 Thin Film Cathode Grown by Pulsed Laser Deposition. S.B.Tang, L.Lu, M.O.Lai: Philosophical Magazine, 2005, 85[24], 2831-42