Preparation of Nitrogen‐Rich Porous Carbon by One‐Pot Pyrolysis for High‐Performance Supercapacitor

Biomass‐derived carbon has become an ideal supercapacitor electrode material for its unique pore structure and favorable surface functional group modulation ability, demonstrating growing significance in electrochemistry. Based on this, this work adopted coconut shell as a carbon electrode precursor to fabricate flake‐like nitrogen‐containing porous carbon electrodes. This is achieved by pyrolysis in a one‐pot method using CH 3 COONH 4 as a combined nitrogen source and templating agent, alongside KHCO 3 as a green activator, providing an eco‐friendly alternative to the conventional KOH method. The templating agent swelled the carbon pore channels during pyrolysis, and the gas stripping overflow further squeezed and ablated the pores, enlarging the pore diameters. At the same time, N atoms replace C atoms and form a large number of active sites for redox reactions in the carbon structure, providing additional charge and thus expanding the capacitance. The best sample exhibited a mass specific capacitance of 302.2 F/g at 0.5 A/g current density in 6 M KOH solution, and the supercapacitor fabricated from this sample had a maximum energy density of 9.19 Wh/kg and a maximum power density of 5,000 W/kg. The supercapacitors maintained 100% Coulombic efficiency and 99.38% capacity retention after 12,000 cycles, which demonstrated the excellent electrochemical performance of the device.