Green power from scraps: renovating fruit and vegetable waste into high-performance supercapacitor electrodes—a comprehensive review

Abstract

This review comprehensively examines the potential of activated porous carbon materials derived from fruit and vegetable waste as sustainable electrode materials for supercapacitor applications. Particular emphasis is placed on the synthesis methodologies, physicochemical characterization techniques, and electrochemical performance evaluation, including specific capacitance, energy density, and cycling stability. Recent findings demonstrate that carbon derived from potato peels achieved an exceptionally high specific capacitance of 1987.5 F/g at 0.2 A/g, while carbon derived from corncobs exhibited 1360.0 F/g at 1.0 A/g, highlighting the excellent electrochemical capabilities of certain biomass sources. In contrast, banana peel-derived carbon showed a much lower specific capacitance of 0.8 F/g at 50 mV/s, underlining the critical role of precursor selection and activation strategy. Additionally, this review discusses how different activation techniques applied to the same biomass precursor, such as coconut shells, led to significant variations in surface area (1567.0, 250.5 and 2143.6 m²/g) and corresponding specific capacitance values (449.0 F/g at 1.0 A/g, 186.5 F/g at 10 mV/s, and 317.0 F/g at 0.5 A/g). These observations underscore the profound influence of activation methods on pore structure development, surface chemistry, and resultant electrochemical behaviour. Overall, the study highlights the dual advantages of utilizing biomass waste—advancing high-performance energy storage technologies while promoting environmentally sustainable and cost-effective material production. A comparative analysis is provided to facilitate the identification of optimal precursors and processing techniques for future research and application development.

Graphical abstract