Redox Stability and Conductivity of Nb Doped SrTiO3 for SOFC Anodes

This study investigated the development of novel electronically conductive ceramic materials for use in redox-stable solid oxide fuel cell (SOFC) anodes. The conductivity of bulk SrNb_xTi_1-xO₃ (SNT), for x = 0.05, 0.1, and 0.2, was measured for samples sintered in air as well as samples sintered under reducing conditions. The conductivity of reduced bulk samples was measured to be of order 10 S/cm under relevant fuel cell operating and redox conditions. In addition, the electronic conductivity of porous SNT/yttria-stabilized zirconia (YSZ) composites was measured to be of order 1 S/cm. All samples sufficiently maintained conductivity with redox cycling at 973 K and 1073 K. X-ray diffraction (XRD) data suggest the SNT and YSZ do not react, indicating compatibility of the composite materials.