Electrical conductivity and stability of A-site deficient (La, Sc) co-doped SrTiO3 mixed ionic-electronic conductor

Mixed ionic-electronic conductors with high ionic conductivity play an important role in modern solid-state ionic devices. The ionic conductivity of SrTiO3-based materials can be significantly improved by creating deficiency on the A-site and acceptor-doping on the B-site. We report in this paper a remarkable enhancement of ionic conductivity, sinterability and thermal stability of (La, Sc) co-doped SrTiO3 by creating deficiency on the A-site. The ionic conductivity of (La0.3Sr0.7)(0.95)Sc(0.10)Ti(0.9)0O(3-delta) varies from 0.005 S/cm at 500 degrees C to 0.01 S/cm at 700 degrees C and to 0.018 S/cm at 950 degrees C in 5%H-2/Ar. These values are nearly eight times higher than that of La0.3Sr0.7TiO3-delta at T >= 700 degrees C. The A-site deficiency in (La, Sc) co-doped SrTiO3 also improves the thermal and electrical stabilities in various atmospheres. A possible charge compensation mechanism among defects in the (La0.3Sr0.7)(0.95)Sc0.10Ti0.90O3-delta is also discussed. (C) 2011 Elsevier B.V. All rights reserved.