Impact of electrolyte concentration on electrochemical performance of Cocos nucifera Waste-Derived High-Surface carbon for green energy storage

[Display omitted] •Biomass waste transforms into high-performance carbon material for supercapacitors.•ZnCl2-assisted carbonization and KOH activation yield high-surface CHSC.•6 M KOH crucial for superior ion diffusion and electrochemical performance.•Achieves 559.27F/g capacitance, 80.37 % stability after 20,000 cycles. The increasing popularity of utilizing biomass's natural structure represents a promising avenue for sustainable innovation, as it taps into the inherent characteristics of organic materials to address various environmental and industrial challenges. Researchers and industries continue to explore the full potential of biomass in creating more sustainable and efficient solutions. The transformation of biomass into carbon materials is an indirect means of utilizing CO2 as a carbon source, thus contributing to the sustainable development of energy storage technologies and also in pollution reduction. In the quest for sustainable energy solutions, this research unveils a cost-effective approach to supercapacitor development by harnessing the untapped potential of Cocos nucifera trunk sawdust-derived high-surface carbon (CHSC). Through a meticulous process involving ZnCl2 treatment and KOH activation at varying temperatures, CHSC-700 emerges as a standout electrode material with exceptional structural characteristics, boasting enhanced graphitization and a specific surface area of 1153.72 m2/g. Further, the study delved into the nuanced relationship between electrolyte concentration and supercapacitor performance, pinpointing 6 M KOH as the optimal condition. In 6 M KOH, the electrode exhibits a maximum specific capacitance of 559.27F/g at the current density of 0.5 A/g with outstanding cyclic stability, retaining 80.37 % capacitance after 20,000 cycles and an impressive energy density of 18.92 Wh/kg and power density of 246.75 W/kg. This systematic exploration provides valuable data for understanding the biomass-derived carbon electrode's behaviour under various electrolyte concentrations, offering crucial information for optimizing its performance in practical applications, such as energy storage devices.