Palmyra (Borassus flabellifer) fruit fiber-derived activated biocarbon for supercapacitor applications: A comparative study on the effects of activating agents

Palmyra (Borassus flabellifer) fruit fiber was effectively converted into activated biocarbon via chemical activation. The effects of using KOH, ZnCl2, and H3PO4 as the activating agents on the physicochemical properties were investigated through various analytical techniques. The chemical activation leads to the production of biocarbons with enhanced specific surface area and porosity compared to their pristine counterpart, which greatly depends on the nature of the activating agents. The specific surface area of H3PO4, KOH, and ZnCl2, activated biocarbons were found to be 505.37 m2 g−1, 766.24 m2 g−1, and 264.05 m2 g−1, respectively. The synthesized activated biocarbon materials were effectively used to fabricate electrodes for supercapacitors. The supercapacitor fabricated using KOH-activated biocarbon exhibits the highest specific capacitance of 148 Fg−1 at 1 Ag−1 compared to ZnCl2 (90 Fg−1) and H3PO4 (122 Fg−1) activated biocarbon materials. Further, the energy and power density of the capacitive cell fabricated using KOH-activated biocarbon are found to be 5.25 Wh.kg−1 and 270 W.kg−1at 1 Ag−1, respectively.