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 m²·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.