Abstract: Сonditions were considered for the synthesis of the Ru _xMnO _y∙nH ₂O nanocomposite layers by the ionic deposition method based on successive repeated redox reactions on the substrate surface in a layer of adsorbed Mn(II) cations and RuO ₄ molecules. It was found that, under the chosen synthesis conditions, on the nickel surface ruthenium-doped manganese(IV) oxide layers are formed, which have a triclinic crystal structure and consist of a set of nanosheets about 5 nm thick and 20–50 nm in lateral dimensions. Based on the experimental data obtained, the features of chemical reactions occurring on the substrate surface during treatment with each of the reagents were considered. The supercapacitor electrodes obtained using these layers and nickel foam are characterized by a capacitance of 687 F/g in 1 M Na ₂SO ₄ solution at a charge-discharge current of 1 A/g.