Converting Corncob to Activated Porous Carbon for Supercapacitor Application.

Carbon materials derived from biomass are promising electrode materials for supercapacitor application due to their specific porosity, low cost and electrochemical stability. Herein, a hierarchical porous carbon derived from corncob was developed for use as electrodes. Benefitting from its hierarchical porosity, inherited from the natural structure of corncob, high BET surface area (1471.4 m²·g-1 ) and excellent electrical conductivity, the novel carbon material exhibited a specific capacitance of 293 F·g-1 at 1 A·g-1 in 6 M KOH electrolyte and maintained at 195 F·g-1 at 5 A·g-1 . In addition, a two-electrode device was assembled and delivered an energy density of 20.15 Wh·kg-1 at a power density of 500 W·kg-1 and an outstanding stability of 99.9% capacitance retention after 4000 cycles.