Redox Reactions in a Layer of Adsorbed Mn(II) Cations and RuO₄ Molecules. Synthesis of Manganese Oxide Doped with Ruthenium by Successive Ionic Layer Deposition

Abstract— Сonditions were considered for the synthesis of the Ru_xMnO_y∙nH₂O 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 RuO₄ 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 Na₂SO₄ solution at a charge-discharge current of 1 A/g.