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 a nd Fe doped SrTiO3 are widely influenced by composition. In contrast to La free compositions, La containing compositions show high stability against r eaction with yttria stabilised zirconia (YSZ) and a closely matching therma l expansion coefficient (similar to1 X 10(-5) K-1). Faradaic efficiency mea surements for Sr0.97Ti0.6Fe0.4O3-delta, and La0.4Sr0.5Ti0.6Fe0.4O3-delta sh ow ionic transference numbers in air between 5 x 10(-3) to 4 x 10(-2), and 2 x 10(-4) to 6 x 10(-4) respectively, decreasing with decreasing temperatu re. The substitution of La for Sr is observed to deplete the level of both ionic and total conductivity obtained in air. (C) 2001 Published by Elsevie r Science Ltd.