Arginine-functionalized graphene oxide for green and high-performance symmetric supercapacitors

The present paper intends to show how a graphene-based composite has effortlessly been synthesized utilizing the arginine amino acid (Arg) as a supercapacitor electrode via a green process with neither organic nor toxic substances in aqueous electrolyte (KOH 6 M). Arg amino acid molecules were used as interfacial spacer of graphene sheets to obstruct aggregation. Hence, the surface area increased and the efficient diffusion of electrolyte ions was facilitated in consequence of generating a 3D porous graphene structure. Besides, the surface chemistry of graphene is tuned as amine and carboxylic acid groups are present in the Arg structure which results in high capacitance through electrode wettability and improved diffusion of electrolyte ions into the electrode structure as well as through pseudo-faradic reactions. The as-fabricated electrode provides an exceptional specific capacitance of 295 F g⁻¹ in 1 A g⁻¹ and effective cycling stability (94% after 4000 cycles) in the design of two-electrode configuration. Considering environmental compatibility as well as the superior power and energy density (2204 W kg⁻¹ and 50 Wh Kg⁻¹, respectively), the striking ability of Arg/GO composite to become an appropriate choice for future generations of energy storage devices is proven.