Facile and Scalable Fabrication of Nitrogen-Doped Porous Carbon Nanosheets for Capacitive Energy Storage with Ultrahigh Energy Density

Porous carbon materials are the most commonly used electrode materials for supercapacitors because of their abundant structures, excellent conductivities, and chemical stability. However, the manufacture of carbon materials possessing sizable pores and remarkable wettability with the electrolyte remains challenging. Herein, we developed a facile and industrially scalable method for the production of nitrogen-doped porous carbon nanosheets (PNDC-4) with excellent pore size distribution, large specific surface area (>1200 m2 g–1), high conductivity (>700 S m–1), and superb wettability either in aqueous or organic electrolyte. Particularly, PNDC-4 shows a high capacitance of 387 F g–1 (1 A g–1) in a three-electrode system with 3 M KOH and 80 F g–1 (1 A g–1) in a symmetric two-electrode system with EMIMBF4. The device exhibits an ultrahigh energy density of 81 W h kg–1 at a power density of 1.3 kW kg–1 and can still maintain at 60.8 W h kg–1 when the power density is increased to 266.6 kW kg–1. Moreover, the devices show superb stability that 94% of its initial capacitance is still maintained after 100 000 cycles at 20 A g–1.