Efficient preparation of porous carbons from coal tar pitch for high performance supercapacitors

Porous carbons (PCs) for supercapacitors were prepared from coal tar pitch by a one-step microwave-assisted KOH activation with low KOH consumption. The surface area of the PC (PC2–M) made at a KOH/pitch mass ratio of 2 with microwave heating for 30 min reaches 1786 m2/g. The electrochemical performance of the PC electrode for supercapacitors was evaluated in different electrolytes including KOH, K2SO4, Na2SO4, Li2SO4 in water, and tetraethylammoniatetra fluoroborate in propylene carbonate. The supercapacitors have a high specific capacitance of 267 F/g in 6 mol/L KOH aqueous electrolyte at 0.1 A/g and a high energy density of 12.0 Wh/kg at 1318 W/kg in a 0.5 mol/L K2SO4 neutral electrolyte. The one-step microwave-assisted KOH activation is a simple, efficient and low energy-consumption approach for the preparation of high performance PCs for supercapacitors.