Using potassium hydroxide as the reduction agent, a stable aqueous dispersion of graphene nanosheets was successfully prepared and characterized for its structural and electrochemical properties for supercapacitor application. The structure and morphology of the as-prepared material were investigated by Fourier transform infrared spectra, X-ray diffraction pattern and high resolution transmission electron microscopy, respectively. The electrochemical supercapacitive properties of as-prepared material were evaluated using cyclic voltammetry, galvanostatic charge-discharge methods and electrochemical impedance spectroscopy. The as-prepared material showed maximum specific capacitance of (200 F g(-1)) in 6.0 M aqueous KOH electrolyte at scan rate 5 mV s(-1). For comparison, we add the data of traditional chemical reduction agent-hydrazine. (C) 2012 Elsevier B. V. All rights reserved.