Self-assembled templated pulp of Citrus limetta porous Biochar@H3PO4 activated cathode for zinc-ion hybrid supercapacitors

This study investigates the utilization of <i>Citrus limetta</i> waste pulp as a renewable agro-waste-derived material for energy storage applications, specifically in zinc-ion hybrid supercapacitors (ZIHSCs). Soft-templated synthesis is employed to synthesize the porous template biochar (CL@CTAB_850°C) through hydrothermal treatment followed by pyrolysis at 850°C. To boost the surface properties of the porous template, it undergoes further chemical treatment (H₃PO₄), resulting in improved physicochemical and electrochemical performance. The fabricated ZIHSC device exhibits high electrochemical performance for CL@CTAB@H₃PO₄_850°C cathode. The scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) results confirm the porous nature of the materials. The ZIHSC device exhibits excellent self-discharge behavior with high voltage retention, addressing key challenges in current energy storage technology and advancing its potential for practical implementations. This research highlights a resource-efficient and waste-valorizing approach for creating high-performance carbon electrodes, demonstrating the potential of agro-waste valorization in energy storage and ZIHSC devices.