CORROSION RESISTANT ELECTRODES / CURRENT COLLECTORS FOR ANODES OF ELECTROLYSIS CELLS WITH SOLID POLYMER ELECTROLYTE

Abstract

The paper deals with the corrosion resistant electrodes production by the environmentally friendly magnetron sputtering for use in the acid electrochemical systems with solid polymer electrolyte, in particular, fuel cells, electrolyzers, and oxygen pumps. A technique was found for obtaining electrodes with electrochemical stability that was close to the stability of platinum, but with a sharply reduced content, which would reduce the cost of the corresponding installation. As the basis for the electrodes, titanium was chosen. Both smooth titanium foil and porous titanium were used. Applied coatings consisted of palladium, platinum or platinum with carbon. The coatings thickness and microstructure were tested using Rutherford backscattering and electron microscopy. The stability tests were carried out in 1 M sulphuric acid at 25oC and current density of 50 mA/cm 2 . The application of these coatings is shown to increase sharply the stability of electrodes and current collectors of titanium foils and porous titanium. The coatings obtained at a direct current sputtering and a negative bias voltage on the titanium substrate have the most dense structure and high stability. In the pulsed mode, the stability was worse and decreased with increasing pulse frequency when obtaining a more porous structure. Comparison of the coatings with different compositions shows that stability of the coating with platinum is higher than stability of the coating with palladium and platinum with carbon. The resulting materials are expected to be used in fuel cells and electrochemical oxygen pumps.