Novel Averrhoa bilimbi Linn. water-based natural acidic aqueous electrolyte assembled with activated carbon from A. bilimbi L. fruit waste for electrochemical energy storage system

In this work, Averrhoa bilimbi Linn. fruit was exploited in a dual function for the fabrication of symmetric supercapacitor devices. Specifically, A. bilimbi L. fruit water was employed as a novel natural acidic aqueous electrolyte, while activated carbon derived from A. bilimbi L. fruit waste was synthesized as the electrode material via a chemical impregnation method. The primary objectives were to explore the viability of A. bilimbi L. fruit water as an innovative natural electrolyte solution and to evaluate the impact of various chemical impregnation agents on the electrochemical performance of the activated carbon electrodes within the A. bilimbi L. fruit water-based electrolyte. The ABAC-K-800 demonstrated a high S_BET of 937.7 m² g⁻¹. Among the samples, the ABAC-H-800 exhibited a remarkable specific capacitance of 287.8 ± 6 F g⁻¹ at 1 A g⁻¹. Furthermore, this device achieved a high energy density of 39.97 ± 0.86 Wh kg⁻¹ coupled with a power density of 1050.42 W kg⁻¹. This work not only introduces an innovative strategy for the application of A. bilimbi L. fruit water as a sustainable electrolyte in supercapacitors but also establishes a facile and effective approach to fabricate high-performance symmetric supercapacitor devices from biomass-derived activated carbon, thereby contributing to the development of eco-friendly and cost-effective energy storage technologies.