Hierarchical Porous Carbons Derived from Renewable Poplar Anthers for High‐Performance Supercapacitors

Abstract Hierarchical porous carbons with granular shape were prepared from waste biomass poplar anthers (PA) by pre‐carbonization and following KOH activation. The pore structure and surface chemistry of PA‐derived carbon can be controlled by adjusting the activation temperature. The material activated at 800 °C possesses a high surface area of 3639 m 2 g −1 , abundant mesopores, and appropriate amounts of oxygen‐ and nitrogen‐containing species. As a result, it exhibits excellent electrochemical performances as a supercapacitor electrode. The specific capacitance reaches 361.5 F g −1 at a current density of 0.5 A g −1 in 6 M KOH aqueous solution. In addition, it shows an impressive energy density of 60.8 Wh kg −1 at a power density of 10416.7 W kg −1 in the ionic liquid BMIMBF 4 . Particularly, a high electrochemical stability and an excellent reversibility were observed in both aqueous and non‐aqueous electrolytes.