The stability and mixed conductivity in La and Fe doped SrTiO3 in the search for potential SOFC anode materials

Both physical properties and the level of mixed conduction obtained in La and Fe doped SrTiO3 are widely influenced by composition. In contrast to La free compositions, La containing compositions show high stability against reaction with yttria stabilised zirconia (YSZ) and a closely matching thermal expansion coefficient (∼1×10−5 K−1). Faradaic efficiency measurements for Sr0.97Ti0.6Fe0.4O3–δ and La0.4Sr0.5Ti0.6Fe0.4O3–δ show ionic transference numbers in air between 5 × 10−3 to 4 × 10−2, and 2 × 10−4 to 6 × 10−4 respectively, decreasing with decreasing temperature. The substitution of La for Sr is observed to deplete the level of both ionic and total conductivity obtained in air.