Promising Cathode Materials for Solid Oxide Fuel Cells

PURPOSE. The cathode in a solid oxide fuel cell is responsible for reduction of oxygen molecules to oxygen ions, which then migrate through the electrolyte to the anode. The thermophysical properties of the cathode material play a crucial role for the performance and efficiency of the fuel cell. So, creation of the cathodes of solid oxide fuel cells (SOFCs) requires taking into account the thermal and chemical stability, as well as analysis of the main characteristics of the cathodes, such as the electrocatalyst activity, electrical conductivity, and mechanical strength. This article presents a review of scientific literature on the qualitative characteristics of SOFC cathodes made of various alloys, as well as their operation parameters. In the review, results of functioning of such cathodes are compared in view of possible improvement of their performance parameters in dependence on the composition of the materials used. The composition and microstructure of cathode materials have a great influence on the characteristics of SOFCs. A rational composition of materials is ensured by controlled oxygen non-stoichiometry, and some aspects of defects can improve the ionic and electronic conductivity, as well as catalytic properties for the oxygen reduction in the cathode.