Sustainable synthesis of polyaniline and activated carbon using citrus limetta peel for asymmetric supercapacitors

Abstract

The sustainable synthesis of energy storage materials having good ion transport mechanisms is the need of the hour. Conducting polymers like polyaniline is an excellent pseudocapacitive material. In our work, we sustainably synthesized polyaniline and activated carbon from the citrus waste with enhanced electrochemical properties. To study the electrochemical behavior 1 M H2SO4 electrolyte was used. The polyaniline electrode showed a specific capacitance of 647 F g−1 at the current density of 0.5 A g−1. The pseudocapacitive nature of polyaniline is due to the emeraldine to leucoemeraldine redox transitions. The inner (intercalation) and outer (surface) charges stored by polyaniline were approximately 39 and 61%, respectively. Also, the full-cell polyaniline//AAC asymmetric system showed a maximum specific energy of 35.3 Wh kg−1 and a corresponding specific power of 250 W kg−1 at a current density of 0.5 A g−1 with an operating potential of 1 V. The specific power of 5056 W kg−1 and specific energy of 6.7 Wh kg−1 were obtained at a much higher current density of 10 A g−1. A capacitance retention of 90.12% was observed after 2500 cycles. This detailed study of polyaniline shows excellent charge storage capability and makes it a potential material that can be used for energy storage applications as a pseudocapacitive material. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.