3D-porous activated carbon morphological modification of Manihot esculenta tuber and Bambusa blumeana stem for high-power density supercapacitor: Biomass waste to sustainable energy

Activated carbon derived from biomass is an environmentally friendly and low-cost supercapacitor electrode material. The diverse morphology and pore shape of activated carbon have a significant impact on enhancing the storage capacity of supercapacitors. However, the disparate distribution of pore sizes in activated carbon has a negative effect on energy density. In the present study, the synthesis and modification of the carbon pore structure of Manihot esculenta tuber and Bambusa blumeana stem was carried out using a sonochemical-assisted hydrothermal method with various chemicals (0.06 M KOH, 0.06 M PVP, 0.06 M ZnCl₂). The 3D pore structure of the sample modified with 0.06 M ZnCl₂ exhibited a well-defined microporous architecture and a substantial specific surface area of 516.29 m²g⁻¹, leading to excellent electrochemical performance in coin cell supercapacitors. A high power density of 1086.12 Wkg⁻¹ at a voltage window of 2 V has been attained, with a corresponding current density of 0.3 Ag⁻¹. Remarkably, after 5000 charge and discharge cycles, the capacitance retention was maintained at 90.8 %. The high power density produced from biomass activated carbon based on Manihot esculenta tuber and Bambusa blumeana stem modified using 0.06 M ZnCl₂ provides a practical approach for environmentally friendly electrical energy storage devices and realizes rapid mass transportation.