Green synthesis of activated carbon from biomass waste of date palm seeds: A sustainable solution for energy storage and environmental impact

Pursuing green, sustainable, and efficient energy storage devices has accelerated the development of techno-economically viable and environmentally benign activated carbons (ACs) derived from natural waste resources. Traditionally, chemical activation has been the favored approach to produce highly porous carbons; however, the environmental hazards posed by conventional chemical activators have shifted towards more sustainable and less corrosive alternatives. This study presents a novel synthesis of high-performance porous AC from waste biomass of date palm seeds, employing sodium oxalate (Na₂C₂O₄) as a greener organic activating agent. This innovative method utilizes agricultural waste effectively and mitigates the environmental concerns associated with traditional chemical activators. The resultant AC, labeled AC-4, demonstrates outstanding electrochemical properties, boasting a specific surface area of up to 1630 m²/g. When evaluated in a symmetric supercapacitor (SC) configuration, AC-4 exhibited a specific capacitance of 112 F/g at a current density of 0.5 A/g and achieved a significant energy density of 16 Wh/kg at a power density of 250 W/kg. Moreover, the AC-4-based symmetric SC showcased exceptional durability and stability, retaining approximately 97 % of its capacitance and a Coulombic efficiency of around 94 % over 10,000 charge-discharge cycles, highlighting its robustness and suitability for next-generation energy storage applications. A preliminary life cycle assessment was conducted to analyze the environmental impact across the entire life cycle of AC-4, from resource extraction to end-of-life disposal. The findings confirm a reduced ecological footprint, underscoring the potential of Na₂C₂O₄-ACs to advance sustainable energy storage technologies. Integrating this sustainable AC into SC technology aligns with eco-friendly manufacturing practices and sets a new benchmark for high-performance energy storage devices produced from waste materials.