All-biomass electrochemical supercapacitors cell utilizing date stone-derived activated carbon electrodes and cellulose hydrogel electrolyte

In this pioneering study, we introduce an all-biomass supercapacitor (SC) derived from date stone biomass, a prominent agricultural byproduct in Saudi Arabia. This novel approach leverages date stones' intrinsic properties to fabricate electrode materials and electrolytes, presenting a sustainable solution to waste management and energy storage. The electrodes are made from date stone-derived activated carbon (DSAC), optimized for high surface area and electrochemical reactivity, while the electrolyte is a novel cellulose hydrogel (date stone-derived cellulose [DSDC]-sodium hydroxide [NaOH]-Urea) extracted directly from date stone biomass. Our electrochemical analysis showcases the SC's exceptional performance, featuring a high specific capacitance of 113.75 F g −1 at a current density of 0.5 A g −1 and an impressive energy density of 40.44 Wh kg −1 at a power density of 400 W kg −1 . Notably, the device operates within a wide 1.8 V potential window, outperforming traditional aqueous electrolytes, and maintains 107.42% capacitance retention with nearly 100% Coulombic efficiency after 5000 cycles. These findings underscore the potential of date stone biomass not only as a sustainable source of energy storage materials but also as a pivotal component in developing advanced SCs. This research paves the way for further exploration into cost-effective and environmentally friendly energy solutions, particularly in regions rich in biomass resources.