Abstract
Aqueous batteries and supercapacitors utilizing water-based electrolytes present safer, cost-effective, and environmentally sustainable alternatives to conventional organic systems, eliminating the need for complex battery management protocols. Despite these advantages, most current aqueous systems depend on scarce transition metals such as nickel, cobalt, and manganese. This has spurred interest in organic electrode materials composed of earth-abundant elements (C, H, O, N, S). BiomassBiomass-derived activated carbonCarbon (AC) precursors, including hemp, honeydew peel, and eggshells, are gaining traction due to their sustainabilitySustainability and promising electrochemical performance. Preliminary investigations at Murdoch University demonstrate that hemp-based composites, synthesized via a simple one-step process, produce AC with a high surface area (1195 m2/g) and excellent electrochemical double-layer capacitance. Scanning electron microscopy (SEM) and cyclic voltammetry analyses reveal that hemp-derived AC surpasses commercial AC in performance, offering a viable solution to interface challenges in aqueous energy storageEnergy storage systems. Interestingly, AC derived from honeydew peel exhibits significantly higher specific capacitance (478 F/g in 1 M H₂SO₄) compared to industrial hemp (105 F/g in 2 M Na2SO4 electrolytes). These compelling results are explored in this proceeding, emphasizing how variations in functional groups, porosity, and redox-active sites in biomassBiomass materials contribute to pseudocapacitive behavior and enhanced energyEnergy density. Notably, honeydew peel-derived AC achieves an energyEnergy density of 66 Wh/kg and a peak power density of 662 W/kg in a symmetric capacitor configuration.