Evaluation of zinc-ion hybrid super-capacitor based on chemically activated (KOH/H3PO4) ground nutshell biochar

In the realm of advancing energy storage technologies, the efficacy of natural biomass sources in mitigating environmental constraints has gained prominence. This study delves into the evolving landscape of energy storage devices, specifically batteries, super-capacitors, and the nascent domain of zinc-ion hybrid super-capacitors (ZIHSC). The focus centers on biomass-derived highly activated carbon, a burgeoning field of research esteemed for its diversity, environmental compatibility, distinctive structural attributes, and unique surface characteristics. This investigation presents a comparative analysis of activated carbons derived from ground nutshell (GS) in the context of ZIHSC applications. Emphasis is placed on the significance of a straightforward biochar synthesis process and subsequent chemical activation. The activated biochar, denoted as GS-H₃PO₄ and synthesized using H₃PO₄, exhibits a discernibly higher Brunauer Emmett Teller (B.E.T.) surface area when juxtaposed with pre-carbonized ground nutshell (GS-Biochar).The ZIHSC cell incorporating GS-H₃PO₄ manifests noteworthy energy density metrics, registering at 50.28 Wh Kg⁻¹ (100 W Kg⁻¹) and 11 Wh Kg⁻¹ (2 kW Kg⁻¹). Additionally, it demonstrates a specific capacitance of 199 F g⁻¹ (2 mV s⁻¹). These findings underscore the promising potential of H₃PO₄-derived activated carbon in optimizing cathode performance for Zinc-ion hybrid super-capacitors. This study contributes to the growing understanding of biomass-derived materials, offering insights into the nuanced interplay between synthesis methods and electrochemical properties, crucial for advancing sustainable energy storage solutions.