Ambient plasma is applied to graphite oxide electrodes directly to improve electrochemical properties for supercapacitor applications. Surface morphology of the electrodes after the plasma treatment changes dramatically and amount of oxygen reduced significantly, demonstrating a reduction effect on the graphite oxide electrode by the ambient plasma. Equivalent series resistance of the electrode also reduced from 108 Omega to 84 Omega after the plasma treatment. Corresponding specific capacitance, therefore, increases from 0.45 F cm(-2) to 0.85 F cm(-2), proving that the ambient plasma treatment is very efficient, clean, economic, and environment-friendly method to reform the graphite oxide electrodes directly for the supercapacitor applications. (C) 2017 Elsevier B.V. All rights reserved.