Synthesis and electrical properties of Co-doped Y0.08Sr0.92TiO3-δ as a potential SOFC anode

Strontium titanate with perovskite structure is one of potential candidates for alternative anodes for solid oxide fuel cells. Co-doped Y0.08Sr0.92TiO3-delta was synthesized via solid-state reaction. The effect of Co-doping on the electrical behavior of Y0.08Sr0.92TiO3-delta was investigated and a doping mechanism was proposed. Compared with Y0.08Sr0.92TiO3-delta, the electrical conductivities of Y0.08Sr0.92CoxTi1-xO3-delta decrease obviously with increasing Co-doping amount at 25-1000 degrees C, while the ionic conductivities increase significantly at 500-1000 degrees C. The addition of Co can increase the oxygen vacancy concentration and enlarge the saddle point critical radius r(c), both of them should be responsible for the remarkably enhanced ionic conductivity of Y0.08Sr0.92CoxTi1-xO3-delta. The decreased electronic conductivity of Y0.08Sr0.92CoxTi1-xO3-delta is ascribed to the lowered Ti3+ concentration, caused by the substitution of Co3+. Co-doping increases the oxygen absorption temperature, and thus widens the operation temperature range of doped-SrTiO3. (C) 2008 Elsevier B.V. All rights reserved.