Hierarchical porous carbon obtained from animal bone and evaluation in electric double-layer capacitors

Abstract

Animal bone, an abundant biomass source and high volume food waste, had been converted into a hierarchical porous carbon in a simple two-step sustainable manner to yield a highly textured material. The structures were characterized by nitrogen sorption at 77 K, scanning electron microscopy and X-ray diffraction. The electrochemical measurement in 7 M KOH electrolyte showed that the porous carbon had excellent capacitive performances, which can be attributed to the unique hierarchical porous structure (abundant micropores with the size of 0.5–0.8 and 1–2 nm, mesopores and macropores with the size of 2–10 and 10–100 nm), high surface area ( S BET = 2157 m 2/g) and high total pore volume ( V t = 2.26 cm 3/g). Its specific capacitance was 185 F/g at a current density of 0.05 A/g. Of special interest was the fact that the porous carbon still maintained 130 F/g even at a high current density of 100 A/g.