Peanut bran derived hierarchical porous carbon for supercapacitor

Hierarchical porous carbon has been prepared from peanut bran via hydrothermal carbonization coupled with KOH activation at 800 °C for 1 h. The obtained porous carbon possesses an outstanding specific surface area of 2565 m 2 /g and total pore volume of 1.503 cm 3 /g with mesopores narrowly distributed from 2 to 4 nm. When used as electrode materials for supercapacitor, the hierarchical porous carbon delivers a specific capacitance of 188 F/g at the current density of 0.04 A/g, exhibits cycle stability with 89.3% capacitance retention after 10,000 charge–discharge cycles at 2.0 A/g, and demonstrates low equivalent series resistance of 0.04 Ω. The excellent electrochemical performance is due to the combination of large specific surface area with hierarchical pore structure and moderate amount of surface oxygen functional groups of the hierarchical porous carbon. This new material makes full use of biomass peanut bran to provide a promising material for the electrode of supercapacitor.