A supercapacitor based on a novel redox-mediated gel polymer electrolyte (PVA-H(2)SO(4)-P-benzenediol) and activated carbon electrodes is assembled. The electrochemical properties of the supercapacitor are evaluated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. It is found that the supercapacitor exhibits large specific capacitance (474.29 F g(-1)), high energy density (11.31 W h kg(-1)), and excellent cyclical stability. The good performance for the supercapacitor is due to the capacity-storage mechanism combination of the electrical double layer capacitance and Faradaic pseudocapacitance by p-benzenediol/p-benzoquinone in the electrolyte. (C) 2011 Elsevier B.V. All rights reserved.