Effects of nickel content on the electrochemical performance of nanosized ternary nickel–zinc–cobalt oxide supercapacitors

To improve the electrochemical performance and structural durability of supercapacitors, herein, well-ordered, porous Ni–Zn–Co ternary oxide nanostructures were synthesized by doping Ni to Zn–Co oxide using ultrasonic electrodeposition. Our investigations revealed that Ni–Zn–Co ternary oxide exhibited superior capacity and rate performance when compared to Zn–Co oxide. In particular, the incorporation of 1 mol/L of Ni markedly improved the electrochemical capabilities of the cathode materials. Remarkably, under the influence of ultrasonic power at 500 W, Ni–Zn–Co oxide exhibited a superior mass loading of 6.2 mg/cm2, coupled with exceptional electron transfer efficiency. The growth mechanism and valence composition of Ni–Zn–Co oxides were studied by SEM and XPS analysis. Moreover, electrodes fabricated from Ni–Zn–Co oxide, synthesized via ultrasonic electrodeposition, demonstrated remarkable area capacitance and rate capabilities, achieving an impressive 1.779 F/cm2 at a current density of 3 mA/cm2. Additionally, the supercapacitor incorporating the Ni–Zn–Co oxide electrode exhibited exceptional long-term stability, maintaining a capacity retention rate of 125.2 % over 24,000 cycles in a mild alkaline electrolyte. This study not only contributes to advancing high-performance cathode materials but also offers valuable perspectives on novel techniques for their fabrication.