Tailoring porosity of starch-derived biocarbon for enhanced supercapacitor performance

Abstract

Carbon materials derived from biomass offer promising prospects for energy storage due to their eco-friendly nature, abundance, and distinctive porous structures. In this study, starch powder was used to synthesise activated biocarbon for supercapacitor electrodes. Spherical carbon particles with an average diameter of 250 nm were obtained using hydrothermal synthesis followed by chemical activation with KOH solution. Physical properties were analysed using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, and N2 adsorption/desorption analysis. Optimally activated biocarbon was achieved at an activation temperature of 900°C, exhibiting a specific surface area of 2730 m2 g−1 and an average pore size of 2.69 nm. The mesoporous structure facilitated ion movement, even at a high scan rate. The resultant symmetric supercapacitor exhibited an energy density of 60.16 Wh kg−1 (@140 W kg−1) and a power density of 24,590 W kg−1 (@51.24 Wh kg−1), surpassing commercial activated carbon.