Interaction of a ceria-based anode functional layer with a stabilized zirconia electrolyte: Considerations from a materials perspective

We report on the materials interaction of gadolinium-doped ceria (GDC) and yttria-stabilized zirconia (YSZ) in the context of high-temperature sintering during manufacturing of anode supported solid oxide fuel cells (AS-SOFC). While ceria-based anodes are expected to show superior electrochemical performance and enhanced sulfur and coking tolerance in comparison to zirconia-based anodes, we demonstrate that the incorporation of a Ni-GDC anode into an ASC with YSZ electrolyte decreases the performance of the ASC by approximately 50% compared to the standard Ni-YSZ cell. The performance loss is attributed to interdiffusion of ceria and zirconia during cell fabrication, which is investigated using powder mixtures and demonstrated to be more severe in the presence of NiO. We examine the physical properties of a GDC-YSZ mixed phase under reducing conditions in detail regarding ionic and electronic conductivity as well as reducibility, and discuss the expected impact of cation intermixing between anode and electrolyte.