Enhancing the performance of Zn-ion capacitors with electrochemically tailored NiCo-LDH@Co3O4 nanoflakes on Ni foam

Co3O4 material is superior among various metal oxides due to its good conductivity and abundance while layered double hydroxide (LDH) materials has unique structure with a large specific surface area, exceptional anion exchange efficiency, high electrochemical reactivity, as well as excellent stability. Thus, the synergetic effect of Co3O4 with NiCo-LDH has been employed in this study to boost the power and energy density of cathode material used in the fabrication of zinc-ion capacitor. The as-synthesized NiCo-LDH@Co3O4@NF electrode material design incorporates specific pathways that facilitate swift ion diffusion, allowing for rapid movement of ions within the material. Additionally, the structure supports the quick transportation of electrons, ensuring efficient electron transfer. As a cumulative result of these features, the proposed electrode material exhibits outstanding specific capacitance. The host material (NiCo-LDH@Co3O4@NF) was directly deposited on Nickel foam (NF) via single step electrochemical deposition technique. The fabricated NiCo-LDH@Co3O4@NF material demonstrates remarkable electrochemical performance, exhibiting pseudocapacitive behaviour in an alkaline solution (1 M KOH) and achieving a peak specific capacitance of 1256 mFcm−2. Zinc-ion capacitor is fabricated using zinc plate as an anode and NiCo-LDH@Co3O4@NF as a cathode gives value of specific capacity 8630 mAhcm−2 (6767.8 mFcm−2), power density of 1220 μWcm−2 (956.4 μWcm−2) and energy density of 1950 μWhcm−2, (1530 μWhcm−2) respectively in 1 M KOH + 10 mM Zn (Ac)2 solution. Furthermore, as-fabricated Zinc-ion capacitor has retention rate of 91.5 % over 10,000 cycles with coulombic efficiency 100 %. Thus, this research opens diverse possibilities for the synthesis of transition metal oxide/hydroxides and their composites as an electrode material for highly efficient Zinc-ion capacitor. •NiCo-LDH@Co3O4 nanoflakes deposited on nickel foam.•NiCo-LDH@Co3O4@NF electrode exhibit specific capacitance ∼1256 mFcm−2.•Zn-ion capacitor exhibits maximum capacity 8630 mAcm−2.•Zn-ion capacitor shows outstanding retention rate ∼91.5 %.