Keratin-derived heteroatoms-doped hierarchical porous carbon materials for all-solid flexible supercapacitors

Abstract

In this work, N, O, S co-doped hierarchical porous carbons are developed utilizing low cost and sustainable keratin obtained from chicken feathers as a precursor. The intrinsic composition of keratin and the addition of inorganic acids contributes to the heteroatoms doped in the carbon framework uniformly during pyrolysis. By optimizing the pore structure with KOH, the as prepared H2SO4-KK-3 possesses an ultrahigh specific surface area of 2864 m2 g−1 with a total pore volume of 1.461 m3 g−1. As an electrode material of supercapacitor, the H2SO4-KK-3 demonstrates a high specific capacitance of 270 F g−1 at the current density of 1 A g−1 and displays superior long-term cycling stability with the capacity retention of 98% after 10000 cycles attributed to the fast kinetics of ion transport and more charge-storage surface. The assembled symmetric carbon-based supercapacitor delivers good rate capability and a high energy density of 11.84 W h Kg−1 at the power density of 8525 W kg−1 in a neutral electrolyte. More promisingly, the all-solid device based on H2SO4-KK-3 exhibits outstanding flexibility, which greatly broadens its practicability.