High‐Surface‐Area Nitrogen‐Doped Reduced Graphene Oxide for Electric Double‐Layer Capacitors

Abstract

Abstract A two‐step method consisting of solid‐state microwave irradiation and heat treatment under NH 3 gas was used to prepare nitrogen‐doped reduced graphene oxide (N‐RGO) with a high specific surface area (1007 m 2 g −1 ), high electrical conductivity (1532 S m −1 ), and low oxygen content (1.5 wt %) for electrical double‐layer capacitor applications. The specific capacitance of N‐RGO was 291 F g −1 at a current density of 1 A g −1 , and a capacitance of 261 F g −1 was retained at 50 A g −1 , which indicated a very good rate capability. N‐RGO also showed excellent cycling stability and preserved 96 % of the initial specific capacitance after 100 000 cycles. Near‐edge X‐ray absorption fine‐structure spectroscopy results provided evidenced for the recovery of π conjugation in the carbon networks with the removal of oxygenated groups and revealed chemical bonding of the nitrogen atoms in N‐RGO. The good electrochemical performance of N‐RGO is attributed to its high surface area, high electrical conductivity, and low oxygen content.