The exploration and optimization of electrodes in capacitors with high capacitance, excellent rate capacity and considerable energy density without sacrificing power density remain a great challenge at a high mass loading. Herein, a simple and novel strategy is presented to activate carbon cloth via chemical oxidation and then followed by gamma-ray irradiated reduction process for removing the oxygen functional groups bonded on the surface of carbon cloth. Activated carbon cloth with extensive pore distribution and high surface area was made up into electrodes to measure its energy storage performance Despite only 5.6% change in surface area from oxidized to gamma irradiated carbon cloth (118 and 124.6 m(2)/g), the electrode based on gamma irradiated carbon cloth shows an obvious 74.6% enhancement of area capacitance (from 402 to 702 mF/cm(2)) critically due to the removal of the oxygen functional groups boned on the surface of carbon cloth by the gamma reduction process. It also provides a desirable rate performance of 86% (610 mF/cm(2) at 20 mA/cm(2)) and 110.5% of its original capacitance after 30000 cycles. In order to further corroborate the prospect of the activated carbon cloth, a symmetric device based on the activated carbon cloth was assembled and it shows a maximum energy density of 0.556 mW h/cm(3) and a supreme power density of 1016 mW/cm(3). The promising energy and power characteristics and excellent cycling stability of the activated carbon cloth have high potential for low-cost, high-performance, and flexible supercapacitors. (C) 2016 Elsevier Ltd. All rights reserved.