Nanoporous MnOx thin-film electrodes are synthesized using a combination of pulsed laser deposition (PLO) and electrochemical lithiation/delithiation methods A dense Mn3O4 thin-film deposited by PLO can transform into a nanoporous MnOx thin-film after electrochemical lithiation/delithiation A nanoporous MnOx thin-film electrode exhibits significantly improved supercapacinve performance compared with an as-deposited Mn3O4 thin-film electrode A MnOx thin-film finally transforms into a MnO2 thin-film through an electrochemical oxidation process during continuous cyclic voltammetry scanning (C) 2010 Elsevier B V All rights reserved