FeCl3/KOH two steps activated biocarbon with hierarchical porosity and oxygen-rich for enhanced supercapacitor applications

Biomass waste derived from jackfruit ( Artocarpus heterophyllus ) cores is used to fabricate hierarchical porous activated carbon through chemical activation with Iron(III) chloride (FeCl 3 ) and potassium hydroxide (KOH). Jackfruit is an abundant agricultural by-product in tropical regions, including India, Bangladesh, and Sri Lanka. The activated carbon derived from jackfruit provides a sustainable, low-cost, and high-performance alternative to conventional carbon materials for supercapacitors, thereby aligning with waste valorisation strategies. The prepared carbon displays hierarchical porous structures of both micro and mesopore architectures. They are amorphous and contain functional oxygen groups, as confirmed by X-Ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). A high surface area (1251m 2 g −1 ) was obtained via Brunauer-Emmett-Teller (BET) analysis. The electrochemical performances, via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCD) show high specific capacitance of 310 F g −1 at 0.8 A g −1 from GCD, 331 F g −1 at 10 mV s −1 from CV, and a charge transfer resistance of 0.1410 Ω cm 2 , in three electrode configuration and showing good cycling stability of 87% over 2500 cycles. These results suggest that the activated carbon offers potential application in low-cost and renewable production of carbon materials for supercapacitors applications. • Jackfruit-derived activated carbon was prepared by two steps chemical activation process using FeCl 3 /KOH. • O-doped hierarchical porous activated carbon (1251 m 2 g −1 ) was fabricated. • The two-step activated carbon exhibited a specific capacitance of 310 F g −1 at 0.8 A g −1 . • High energy (19.12 Wh·kg −1 ) and power (5296.15 W kg −1 ) densities were obtained. • Cycling stability over 2500 cycles was assessed using GCD, with 87 % of capacitance retention.