Creation of nanopores and nitrogen doping in the surface layers of reduced graphene oxide electrode via ions implantation resulting in enhanced electrochemical performance for supercapacitor

Abstract

Nitrogen doping is an effective way to enhance the electrochemical performance of carbon materials. In this study, the surface layers of graphene oxide (GO) film was firstly implanted by nitrogen ions, and then annealed at nitrogen atmosphere to obtain the nitrogen-doped reduced GO (NrGO) electrode for supercapacitor. Uniformly distributed nanopores are created in the surface layers of NrGO electrode, and also as high as 9.9 % nitrogen content is doped into its surface layers. The synergistic effects of these surface modifications significantly improve its electrochemical performance. The specific capacitance is increased from 148 F g−1 (original reduced GO (rGO)) to 270 F g−1 (NrGO), tested at current density of 0.5 A g−1 in symmetrical cells with 6 M KOH electrolyte. The volumetric capacitance of NrGO reaches 416 F cm−3, and its volumetric energy density is 14.3 Wh L−1 with power density of 191.7 W L−1. This study provides an exploration via nitrogen ions implantation to fabricate graphene-based electrodes with high electrochemical performance.