▎ 摘　　要

Aqueous redox-active electrolytes can provide a significant improvement in electric energy storage for electrochemical capacitors. Herein, we report a novel hybrid capacitor consisting of porous polypyrrole/ reduced graphene oxide (PPy/rGO-HT) composite electrodes and an aqueous electrolyte with hydroquinone redox-active species. A hydrothermal-assisted synthesis of the PPy/rGO-HT composite allowed to obtain a porous polymer-graphene composite with a high specific surface area of 597 m(2) g(-1). In a three-electrode configuration with the redox-active electrolyte, PPy/rGO-HT exhibits better electrochemical performance in terms of specific capacity and cycling stability compared with that of pristine rGO. An assembled symmetric device achieves excellent long-term stability and a specific energy of 6.5 Wh kg(-1), indicating the potential of hybrid systems for energy storage applications. (C) 2020 The Authors. Published by Elsevier Ltd.