Fabrication of high performance structural N-doped hierarchical porous carbon for supercapacitor

In this paper, a method to fabricate structural N-doped hierarchical porous carbon is proposed. KOH and melamine are found to have synergistically impact on the pore-creating and nitrogen-doping process. The targeted product possesses specific surface area of 2642 m(2) g(-1) with a highly promoted inner surface area. The specific capacitance increases from 364 to 715 F g(-1) at the current density of 1 A g(-1) in a two-electrode system using 6 M KOH electrolyte. It also shows the good rate capability (526 F g(-1) at 100 A g(-1)) and cycle performance (98.28% retention after 5000 cycles at 5 A g(-1)). The energy density reaches 118 W h kg(-1) at the power density of 200 W kg(-1). The high specific capacitance is mostly derived from the electrical double-layer capacitance, which is a significant advantage compared to the conventional surface doping. The nitrogen atoms stably embedded into the carbon skeleton. N-5 hindered the energy storage process, while N-Q showed obvious impact both on the specific capacitance and cycle performance. All in all, a high-performance electrode material for supercapacitor is provided in this study and it also provides a brand-new idea for the structural doping porous carbon. (C) 2020 Elsevier Ltd. All rights reserved.