Low-temperature preparation of nitrogen-doped graphene for supercapacitors

A simple method to prepare nitrogen-doped graphene (NG) by a pressure-promoted process at relatively low temperatures is demonstrated. The NG with an atomic N content higher than 10% can be obtained by heating graphene oxide and NH4HCO3 in a sealed autoclave at a temperature as low as 150 °C. The product exhibits a specific capacitance of 170 F g−1 at 0.5 A g−1 in 5 M KOH, and a high retention rate of 96.4% of its initial capacitance after 10,000 charge/discharge cycles at a current density of 10 A g−1. Such an easy, cost-effective and low-temperature doping process will be promising for preparing devices based on NG.