Facile and sustainable technique to produce low-cost high surface area mangosteen shell activated carbon for supercapacitors applications

In this study, we have reported the effect of different activating agents, temperatures, and impregnation ratios on the porosity of mangosteen shell-derived activated carbons (M-S AC). The sample’s characterization comprised of scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and N2 physisorption analysis. The M-S AC synthesized with K2CO3 as the activating agent displayed a high specific surface area of 2802.6 m2 g−1 and a flower-like morphology. Electrochemical measurements of the M-S AC synthesized with K2CO3 revealed a specific capacitance of 298.13 F g−1 at 0.5 A g−1 in a potential window of −0.9–0.0 V vs Ag/AgCl using 2.5 M KNO3 electrolyte in a three-electrode measurement. An initial symmetric supercapacitor assembled with the optimized M-S AC as electrode material and 2.5 M KNO3 as the electrolyte delivered a specific energy of 11.5 Wh kg−1 corresponding to a specific power of 0.4 kW kg−1 at 0.5 Ag−1 in a potential window of 1.6 V. A second assembled symmetric device using the same M-S AC as electrode material and 1-Ethyl-3-methylimidazolium-bis(fluoroSulfonyl)imide (EmiFSI) ionic liquid as the electrolyte demonstrated high specific energy of 28.03 Wh kg−1 corresponding to a specific power of 0.7 kW kg−1 at 0.5 Ag−1 in a wider potential window of 2.8 V.