Assembly of high-performance zinc-ion hybrid capacitor using soy residue-derived porous carbon as cathode and HCl treated zinc foil as anode

As a secure energy storage device, zinc-ion hybrid capacitors (ZHCs) have garnered significant research attention. Prior investigations have demonstrated that the performance of ZHCs is profoundly impacted by the structural characteristics or compositional design of both the anode and cathode materials, as well as the electrolyte. Consequently, this study employed porous carbon derived from soy residue as the cathode, and HCl treated zinc foil as anode to construct ZHCs. Influence of the preparation condition of the soy residue-derived porous carbon, and the morphology of the zinc foil anode on the assembled ZHCs performance was systematically explored. Utilizing a soy residue-derived porous carbon material with the specific surface area of 3216.2 m² g⁻¹ as the cathode, and a zinc foil anode featuring surface cracks markedly improved the performance of the fabricated ZHCs. The specific capacitance and power density of the assembled ZHC, incorporating the aforementioned cathode and anode, achieved 514.6 F g⁻¹ and 323.5 Wh kg⁻¹, respectively. To ensure the cycling stability of ZHC, the zinc electrode was protected using nickel foam. The assembled ZHC maintained a 100 % specific capacitance retention after 5000 cycles. For the advancement of high-performance ZHCs, it is imperative to refine the structural attributes of the porous carbon cathode and zinc foil anode, alongside optimizing the zinc anode protection method.