Orange peel-derived activated carbon as a potential electrode material for supercapacitor application

Abstract

Supercapacitors are emerging as a viable alternative to batteries in a variety of applications. In recent years, extensive research has been carried out on the development of new electrode material to produce supercapacitors with high energy density. In this study, 2 different types of activated carbon (AC) namely commercialized AC (i.e. steam-activated charcoal) and self-prepared phosphoric acid-treated orange peel AC were used to fabricate the supercapacitor electrodes. Prior to the fabrication, the structural properties and surface morphology of both ACs were examined using the Brunaeuer-Emmett-Teller (BET) analysis and Scanning Electron Microscope (SEM). The results revealed that commercialized AC exhibited more pores on its surface and a higher BET surface area of 818.8441 m2/g than orange peel-derived AC, which had a surface area of 137.9910 m2/g. The fabricated coil cell supercapacitor in sodium sulfate electrolyte demonstrated specific capacitance of 35.5880 F/g for the commercialized AC and 57.7056 F/g for the orange peel-derived AC. Higher energy density was recorded for supercapacitor fabricated using orange peel-derived AC (8.0147 Wh/kg), compared to the commercialized AC counterpart (4.9428 Wh/kg). Despite its inferior physical properties, the superiority of supercapacitor performance (e.g., specific capacitance and energy density) with orange peel AC suggested that there is a potential for orange peel AC-based supercapacitors to be used in real-world applications, but more research on the optimization of electrode composition, type, and electrolyte concentration is required.