Preferred c-axis oriented LiCoO2 thin films were prepared on a Si substrate by pulsed laser deposition (PLD). The chemical diffusion coefficients, D ˜ Li , of Li in these films were measured by electrochemical impedance spectroscopy (EIS) and potentiostatic intermittent titration technique (PITT). D ˜ Li was found to be in the range of 10−11 to 10−13 cm2 s−1 depending on Li concentration and on the characterization method used.