Nitrogen-Doped Graphene as Electrode Material with Enhanced Energy Density for Next-Generation Supercapacitor Application

Abstract

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.