Nitrogen-enriched flexible porous carbon/graphene composite cloth as free-standing electrodes for high performance aqueous supercapacitors

Flexible supercapacitors have attracted great attention with the rising demand of wearable electronics. Herein, cotton cloth was utilized to fabricate a novel kind of high performance flexible electrodes, i.e. nitrogen-enriched porous carbon/graphene composite cloth. The prepared composite cloth is composed of hollow-structured porous carbon/graphene hybrid fibers. The composite exhibits a high specific capacitance of 438 F g(-1) (391 F cm(-3)) in 6 M KOH electrolyte. The assembled symmetric supercapacitor with the composite as electrodes demonstrates excellent energy storage capability, a high capacitance retention of 93% can be achieved after 10,000 cycles at 2 A g(-1) indicating its superior cycling stability. Meanwhile, the supercapacitor can deliver high energy density and high power density. The superior performance is attributed to the improved conductivity, high surface area and abundant micropores of the composite, as well as the extra pseudocapacitive contribution from the enriched heteroatom species.