Hierarchically porous carbon derived from an aqueous curable composition for supercapacitors

Abstract

Hierarchically porous carbon with micropores, mesopores, macropores and high specific surface area for supercapacitors is fabricated from an aqueous curable composition by curing and subsequent carbonization, followed by KOH activation under N2 atmosphere. With the manipulation of KOH activation to the peculiar morphology developed during carbonization, the external specific surface area grows from 208 to 1151m2g−1, while the specific surface area of micropores stays at around 1100m2g−1, leading to the micro/external specific surface area ratio decreases from 5.36 to 0.94. Prepared with KOH/carbon weight ratio at 2.0, the porous carbon with total specific surface area of 1590m2g−1 and moderate micro/external specific surface area ratio of about 2.0, exhibits intriguing electrochemical performance in 1M H2SO4 aqueous electrolyte, such as superior specific capacitance (274Fg−1 at 0.1Ag−1), excellent rate capability (161Fg−1 remained at 20Ag−1) and outstanding cycling stability (no capacitance loss over 5000 cycles). The promising electrochemical performance could be attributed to the synergy of the hierarchically porous morphology and high specific surface area.