Preparation and electrical properties of yttrium-doped strontium titanate with B-site deficiency

Yttrium-doped strontium titanate with B-site deficiency (Y0.08Sr0.92Ti1−xO3−δ) is synthesized via conventional solid-state reaction. The effect of B-site deficiency on the lattice parameter, sinterability, microstructure and electrical properties of Y0.08Sr0.92TiO3−δ is investigated. The charge compensation mechanism for B-site deficiency is proposed. The limit of B-site deficiency in Y0.08Sr0.92Ti1−xO3−δ is below 5 mol % in Ar with 5% H2 at 1500 °C. The sinterability of Y0.08Sr0.92Ti1−xO3−δ decreases slightly with increasing deficiency level (x). Compared with Y0.08Sr0.92TiO3−δ, the electrical conductivity of Y0.08Sr0.92Ti1−xO3−δ samples decreases while the ionic conductivity increases with increasing B-site deficient amount. It is assumed that the deficiency of Ti in Y0.08Sr0.92Ti1−xO3−δ is charge compensated by the increase of oxygen vacancy concentration and the decrease of Ti3+ concentration. Y0.08Sr0.92Ti1−xO3−δ shows a relatively stable electrical conductivity at different oxygen partial pressures and displays an excellent chemical compatibility with YSZ electrolyte below 1200 °C.