Sulfur-tolerant anode materials for solid oxide fuel cell application
This paper summarizes the degradation mechanisms for SOFC anodes in the presence of sulfur and recent developments in sulfur-tolerant anodes. There are two primary sulfur-degradation mechanisms for the anode materials: physical absorption of sulfur that blocks the hydrogen reaction sites, and chemical reaction that forms nickel sulfide. The sulfur-tolerant anodes are categorized into three kinds of materials: thiospinels and metal sulfides, metal cermets, and mixed ionic and electronic conductors. Each material has its own advantages and disadvantages, and the combined application of available materials to serve as different functional components in anodes through proper design may be effective to achieve a balance between stability and performance.