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 N-2 sorption isotherms techniques. The as-prepared NPC exhibited a high BET surface area of 2321 m(2) 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). (C) 2018 Elsevier B.V. All rights reserved.