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 (PC _2-M ) made at a KOH/ pitch mass ratio of 2 with microwave heating for 30 min reaches 1 786 m ² / g. The electrochemical performance of the PC electrode for supercapacitors was evaluated in different electrolytes including KOH, K ₂ SO ₄ , Na ₂ SO ₄ , Li ₂ SO ₄ 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 1 318 W/ kg in a 0. 5 mol/ L K ₂ SO ₄ 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.