Konjac Sponge Derived Carbon Flakes with Optimized Pore Structure for High-Performance Supercapacitor

Abstract

Lamellar activated carbons derived from Konjac sponges (KACs) have been successfully fabricated through a facile KOH activation method. By manipulating the activation temperature and KOH/C ratio, the achieved KACs exhibit ultrahigh specific surface area up to ∼3000 m2/g and hierarchical pore structure with tunable micro/mesopore distribution. Notably, KACs possess plenty of worm-shaped micropores formed by graphene stacking layers with the lateral distance close to size of hydrated electrolyte ions. Owing to optimized pore structure, high graphitization, and extra O/N doping, KACs exhibited much enhanced specific capacitance (253.0 F/g), superior rate ability (77% retention of capacitance at 10 A/g), and remarkable cycling stability (0.4% decay under 5 A/g after 2000 cycles) in the acid electrolyte. The mass production ability of KAC materials and the knowledge of correlation between texture properties and capacitive performance open new opportunities for the application of such novel biomass-derived carbons in supercapacitor devices.