Novel synthesis route for the preparation of mesoporous nitrogen-doped carbons from forestry wastes for supercapacitors

Abstract Biochar has excellent electrochemical properties and is an ideal renewable green material for many types of energy storage equipment. Nevertheless, most of the biochar materials currently reported as supercapacitor electrodes require a great specific surface area above 1000 m2/g. Here, we first reported the use of two forestry wastes, extracted residue of lacquer wax (RP) and Acer truncatum husk (ATH), as biomass raw materials for pre-carburization at 400 °C. After impregnating potassium ferricyanide, a higher temperature heat treatment is carried out to realize the simultaneous activation of pore formation, catalytic graphitization and hetero-element doping. The specific surface area of activated carbon from the extracted residue of lacquer wax (ACRP) activated at 650 °C was only 311 m2/g, but its specific capacitance reached 324 F/g at a current density of 0.2 A/g. And after 3000 cycles, the capacitance retention rate of the prepared working electrode also reached over 97%, indicating that it has an excellent cycle performance. This study provides a feasible technical route and strategy for the preparation of carbon materials with low specific surface area and high electrochemical performance in a three-electrode system.