This project focuses on secondary phase materials added to traditional Ni-based cermet electrodes to enhance SOFC anode durability and performance. Small amounts of an inorganic oxide, aluminum titanate or ALT, mechanically mixed with a nickel-yttria stabilized zirconia (Ni-YSZ) ceramic metallic composite results in a material that is ~50% stronger than the native Ni-YSZ cermet. Furthermore, anodes fabricated from ALT-enhanced Ni-YSZ show significantly slower degradation in solid oxide fuel cells (SOFCs) operating at 800°C with H2. Objectives for this project include, refining methods used to fabricate ALT enhanced anodes into bi-layer anode supports to achieve high power densities; comparing the effects of adding ALT mechanically to Ni-YSZ powders prior to anode fabrication with adding ALT through infiltration and co-infiltration of YSZ scaffolds; testing the resilience of these novel materials to electrochemical and environmental redox cycling and thermal stresses commonly encountered in functioning SOFCs; working closely with SOFC manufacturers to transfer laboratory knowledge to full-sized cell fabrication and testing.

A centerpiece of this effort is anode resilience studies related to sequential oxidation and reduction processes incorporating operando optical methods coupled with electrochemical measurements to identify (in real time) material changes that occur within functioning SOFC anodes under redox cycling stress, which simultaneously correlate to changes in electrochemical conversion efficiency, thermal stability, mechanical robustness and material composition. The effects of secondary phase formation on anode microstructure and strength will be optimized based on results from pre- and post-operation fracture testing of anode-supported membrane electrode assemblies. The distribution and heterogeneity of new material phases will be mapped ex situ using state-of-the-art surface analytical methods.