▎ 摘　　要

Nitrogen-doped graphene (NDG), synthesized from graphene oxide by a hydrothermal process, was used to construct a non-aqueous symmetric supercapacitor. The electrochemical performance of NDG was evaluated using cyclic voltammetry, galvanostatic charge-discharge cycling and impedance analysis in a symmetrical hybrid supercapacitor cell with 1 M tetraethyl ammonium tetrafluoroborate in acetonitrile as the electrolyte. The specific capacitance of NDG is 103 F g(-1) at a current density of 0.5 mA cm(-2). The NDG product exhibits a remarkably high energy density of 97 Wh kg(-1), which is double that of conventional lead-acid batteries. The superior capacitive behavior has also been compared with a few representative capacitor materials. (C) 2015 The Electrochemical Society. All rights reserved.