Low-cost, high-performance supercapacitor based on activated carbon electrode materials derived from baobab fruit shells.

Due to an effective synthesis strategy, two kinds of hierarchical porous activated carbons were derived via KOH and H3PO4 activation and carbonization processes from baobab fruit shells (BFSs) used as a green and low-cost biomass precursor. The physicochemical properties and the morphological structure of the baobab fruit shell derived carbons (BFSCs) were systematically studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra, nitrogen adsorption/desorption isotherms and X-ray photoelectron spectroscopy (XPS) techniques. The biomass-derived activated carbons, BFSC1 (using KOH activation), and BFSC2 (using H3PO4 activation), obtained exhibit high specific capacitances of 233.48 F g-1 and 355.8 F g-1 at a current density of 1 A g-1, respectively, due to their different surface structures and high specific surface areas. Furthermore, the as-assembled, flexible all-solid-state supercapacitor devices based on the BFSC electrodes exhibit a high specific capacitance of 58.67 F g-1 at 1 A g-1 and a high energy density of 20.86 Wh kg-1 at a power density of 400 W kg-1. This facile route highlights the exciting possibility of utilizing waste baobab fruit shells to produce low-cost, green and high-performance carbon-based electrode materials for sustainable electrochemical energy storage systems.