The electrochemical cycling behavior of nanocrystalline MnO2 coatings with a defective antifluorite structure, prepared by anodic electrodeposition, was investigated in terms of morphological and structural evolution. MnO2 electrodes cycled at 100mVs(-1) exhibited improved electrochemical frequency response, compared with as-prepared electrodes. The improved frequency response is attributed to morphological and structural evolution from equiaxed oxide nanocrystals to petal-shaped, single-crystal nanosheets, which follows a dissolution-redeposition mechanism. (C) 2008 Elsevier Ltd. All rights reserved.