ALKALINE WATER ELECTROLYSIS WITH ANION EXCHANGE MEMBRANES AND DIFFERENT TYPES OF ELECTRODES

Abstract

The article is devoted to the creation of a new generation element base for aqueous alkaline electrolyzers with anion-exchange membranes. As a result of the research, two new membranes and various types of electrodes have been 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 values of specific energy consumption. In this case, the electrolysis module consists entirely of electrode-membrane blocks. Their composition includes components tested in industrial alkaline electrolysis, which distinguishes them from known analogues in chemical resistance. Various types of catalysts that can be used as part of membrane-electrode blocks are considered separately. The results of express tests of electrodes made of stainless steel 12X18H10T are presented, the oxidation process of chromium, which is part of the alloy, is shown, which leads to a decrease in its corrosion resistance. When testing electrodes based on a steel mesh coated with a protective layer of nickel, extensive pitting corrosion was detected on the anode during its operation at high current densities. As an alternative, electrodes made of nickel mesh are proposed. These samples showed excellent corrosion resistance and high adhesion to electrodeposited catalysts. Catalytic coatings consisting of nickel or nickel-cobalt powder with additionally chemically precipitated phosphorus were investigated as catalysts.