Life Testing and Redox Cycling of Ni- and Ru-Doped Strontium Iron Titanate Exsolution Fuel Electrodes in Electrolyte-Supported Solid Oxide Cells

Oxide exsolution fuel electrodes for solid oxide cells (SOCs) have shown good initial electrochemical performance compared with conventional Ni-YSZ. Few studies have focused on investigating the long-term durability of these materials and no long-term reversible operation has ever been conducted on cells with these exsolution fuel electrodes. In this study, life tests on electrolyte-supported full and symmetric cells with Sr 0.95 Ti 0.3 Fe 0.63 Ni 0.07 O 3- d (STFN) and Sr 0.95 Ti 0.3 Fe 0.63 Ru 0.07 O 3- d (STFRu) fuel electrodes were conducted under different testing conditions. STFN fuel electrodes tested with 97% H 2 +3% H 2 O showed worse initial stability than cells tested with 50% H 2 +50% H 2 O; this is attributed to a more extensive perovskite-RP phase transformation, as suggested by in-situ X-ray diffraction (XRD) analyses. STFRu was also tested with 97% H 2 +3% H 2 O and showed better stability than STFN.