Mixed nickel-cobalt oxide was prepared by hydrothermal synthesis. Evaluation of the morphology and structure of the produced oxide using scanning electron microscopy and X-ray structural analysis reevaled spinel NiCo₂O₄ formed spherical nanostructures. Electrodes were prepared from composite materials based on nickel-cobalt mixed oxides, polyvinylidene fluoride binder, and carbon black, applied to nickel foam by various methods. Electrochemical studies of electrodes in aqueous alkaline solutions were carried out by the cyclic voltammetry. The obtained values of the specific capacity of the material in charge-discharge cycling reach 840 F/g at 5 mV/s. The best value of the capacity retention of the produced materials was 87% for 100 cycles.