Biochar‐Derived From Rice Husk as Electrode Materials for Supercapacitor Application

ABSTRACT Biochar‐derived from rice husk (BC‐RH) with irregular morphology, microscale size and porous structures was prepared by a simple inert atmosphere sintering strategy, and the optimal preparation conditions were determined to be 800°C for 90 min. The micro‐structure, composition and specific surface area of the BC‐RH were analyzed by different techniques. The proposed biochar was applied as the supercapacitor electrode material and the electrochemical performance of the BC‐RH was investigated by cyclic voltammetry method and galvanostatic charge‐discharge technology. The BC‐RH obtained at 800°C for 90 min exhibits a specific surface area of 245.9 m 2 ·g −1 and delivers a specific capacitance of 78.3 F·g −1 at 0.5 A·g −1 in 6 M KOH electrolyte. The capacitance retention after 5000 cycles is 91.2% showing that the BC‐RH possesses good capacitance cycle stability. The work provides a simple route for high value‐added conversion of rice husk waste into biochar for supercapacitor electrode application.