One-pot synthesis of N-doped hierarchical porous carbon for high-performance aqueous capacitors in a wide pH range

Nitrogen doped porous carbons are the most attractive electrode materials for supercapacitors due to their large surface area and surface pseudocapacitance. Herein, a nitrogen-doped porous carbon with an ultra-high specific surface area of 3709 m2 g−1 is synthesized by a simple one-pot polymerization and calcination process. The porous carbon exhibits both high specific capacitance and excellent rate capability in a wide pH range. High specific capacitances of 304.3, 348.0, 185.4 and 298.0 F g−1 are achieved for the nitrogen-doped porous carbon in 1 M H2SO4, 6 M KOH, 21 m LiTFSI and 1 M Li2SO4 at 2 mV s−1, respectively. The symmetrical supercapacitor with this porous carbon as the electrodes can deliver a high energy density of 25.9 Wh kg−1 at a power density of 339.6 W kg−1 with an operating cell voltage of 1.7 V in 1 M Li2SO4 electrolyte, and a good cycle stability with 84% of its initial specific capacitance remains after 23,000 cycles. The superior electrochemical properties can be attributed to the large specific surface area, well-defined hierarchical pores, and high level of disorder structure for the N-doped carbon material.