Alkaline Water Electrolysis with Anion-Exchange Membranes and Nickel-Based Catalysts

The article is devoted to the development of a new-generation elemental base for aqueous alkaline electrolyzers with anion-exchange membranes. Two new membranes and various types of electrodes are proposed, which significantly increase the purity of the generated electrolysis gases and the operating outlet pressure directly at the outlet of the electrolysis module, while maintaining low specific energy consumption. The electrolysis module consists entirely of membrane-electrode assemblies. Their composition includes components tested in the industrial alkaline electrolysis; they stand out from the known analogues in their chemical resistance. Various types of catalysts that can be used as part of membrane-electrode assemblies are considered. The results of express tests of the 12Kh18N10T-stainless-steel electrodes revealed the oxidation process of chromium, a part of the alloy, which is shown to lower its corrosion resistance. When testing electrodes based on a steel mesh coated with a protective nickel layer, an extensive anode pitting corrosion was detected during its operating at high current densities. As an alternative, nickel-mesh electrodes are proposed. They showed excellent corrosion resistance and high adhesion of the electrodeposited catalysts. Catalytic coatings consisting of nickel or nickel-cobalt powder with chemically deposited phosphorus are investigated as catalysts.