This study exhibits influence of deposition rate on LiCoO2 epitaxial films prepared by pulsed laser deposition. High deposition rates tend to destabilize trivalent Co, resulting in formation of an oxygen-deficient phase with a rock-salt structure as an impurity in the deposited films. Because the oxygen-deficient phase originates from incomplete oxidation, post-annealing in air eliminates the impurity phase. Moreover, since it also improves the crystallinity of the film, the post-annealing enhances the electrode performance of the LiCoO2 films. (C) 2015 Elsevier B.V. All rights reserved.