| Summary: | Metallic oxides are considered promising candidates for supercapacitors owing to their inherent pseudocapacitive behavior and superior electrochemical properties. In this work, NiCo<sub>2</sub>O<sub>4</sub>, CuCo<sub>2</sub>O<sub>4</sub>, and CuCo<sub>2</sub>O<sub>4</sub>@NiCo<sub>2</sub>O<sub>4</sub> composite electrodes are synthesized directly on a nickel foam substrate via the facile hydrothermal method. The phase of the prepared materials was analyzed using the X-ray diffraction method. The morphology of the prepared binder-free electrodes was observed by scanning electron microscopy. The electrochemical testing was done in a 2 M KOH solution against an Ag/AgCl reference electrode. The CuCo<sub>2</sub>O<sub>4</sub>@NiCo<sub>2</sub>O<sub>4</sub> composite electrode demonstrated a value of specific capacitance as high as 422 F g<sup>−1</sup> at a current density of 1 A g<sup>−1</sup> and thus outperformed the NiCo<sub>2</sub>O<sub>4</sub> and CuCo<sub>2</sub>O<sub>4</sub> in terms of its electrochemical performance. The CuCo<sub>2</sub>O<sub>4</sub>@NiCo<sub>2</sub>O<sub>4</sub> composite retained a specific capacitance of 278 F g<sup>−1</sup> even with the increase of current density to 10 A g<sup>−1</sup>, which corresponds to a 34% loss of capacitance compared to 40% and 48% of individual NiCo<sub>2</sub>O<sub>4</sub> and CuCo<sub>2</sub>O<sub>4</sub> electrodes, respectively. Hence, the synergy in a composite material demonstrates it to be a potential candidate as an electrode in supercapacitors.
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