Preparation of activated carbon composite electrode from sugarcane bagasse and its application on energy storage devices

Based on sustainable resource recycling, we utilize physical and chemical activation to modify sugarcane bagasse into activated carbon materials with a porous structure. The activated carbon modified with KOH-KNO₃ exhibits a high specific surface area and excellent specific capacitance, and the fabricated composite electrode demonstrates superior electrical conductivity of 57mS/cm. Subsequently, a supercapacitor containing an electrode, gel electrolyte, and separator is assembled in a sandwich structure. It achieves a specific capacitance of 262.4 F/g, an energy density of 17.9 Wh/kg, and a power density of 2021 W/kg at a scanning rate of 0.02 V/s. Furthermore, the supercapacitor demonstrates excellent cycle stability since it can maintain 98.38% of its initial capacitance after 20,000 cycles of charge and discharge under a constant current. In addition, the KOH-KNO₃-modified activated carbon composite electrode exhibited superior electrochemical performance after we compared it to other carbon electrode supercapacitors derived from agricultural wastes.