Synthesis and performance of A-site deficient lanthanum-doped strontium titanate by nanoparticle based spray pyrolysis

In this study A-site deficient lanthanum doped strontium titanate, which is considered as a promising, redox-stable candidate for full ceramic anodes in Solid Oxide Fuel Cells (SOFCs), was produced by nanoparticle-based spray pyrolysis. In this process cost-effective nitrate salts and titania nanoparticles are used as precursors. LST with a nominal composition of La0.2Sr0.7TiO3 showed limited stability at temperatures higher than 1290 degrees C. It was observed that minor contents of secondary phases, which form at elevated temperatures, invoke a drastic loss of the electrical performance. Thermal stability is significantly increased by a slight enrichment of strontium. The phase pure A-site deficient LST shows remarkably higher electrical performance than similar stoichiometric counterparts. Reductive sintering results in a conductivity as high as 600 S cm(-1) at 600 degrees C. Furthermore the A-site deficient LST shows a high redox-stability and fast redox-kinetics. With these properties IST is a suitable material for the fabrication of a new generation of Ni-free ceramic SOFC anodes. Secondary phases have a significant influence on the electrical conductivity and redox behaviour. (C) 2011 Elsevier B.V. All rights reserved.