High-capacity porous carbons prepared by KOH activation of activated carbon for supercapacitors

High-performance supercapacitor electrode materials are prepared from the commercially available activated carbon (AC) through a facile and low-cost chemical activation method. The obtained results show that AC activated by KOH with an alkali/carbon ratio of 6/1 (ACK6) possesses a specific surface area of 3405   m 2 /g, a large pore volume of 2.01   cm 3 /g, and exhibits the highest initial specific capacitance of 335   F/g at the current density of 0.5   A/g in 6   mol/L KOH, and 85% coloumbic efficiency for 5000 cycles at 20   mV/s.