A high performance nitrogen-doped porous activated carbon for supercapacitor derived from pueraria

In this work, pueraria-based biomass nitrogen-doped porous activated carbon (NPC) was prepared by a simple two-step approach. Firstly, pueraria powder and melamine were fully mixed and hydrothermally treated. Secondly, the as-formed product was directly subjected to the oven for the simultaneous pyrolysis and activation. The as-prepared samples were systematically characterized by SEM, TEM, XPS, XRD, and N2 sorption isotherms techniques. The as-prepared NPC exhibited a high BET surface area of 2321 m2 g−1 with 99% small-size mesoporous structures. In 6 M KOH electrolyte, the NPC electrode delivered a high specific capacitance of 250 F g−1 at a current density of 0.5 A g−1. Even at 10 A g−1, specific capacitance of 231 F g−1 was obtained. Furthermore, an energy density of 8.46 Wh kg−1 at a power density of 123 W kg−1 was obtained with the NPC electrode in a supercapacitor, and it still retained a specific energy density of 7.52 Wh kg−1 at a power density of 2417 W kg−1.