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

Abstract Strontium titanate with perovskite structure is one of potential candidates for alternative anodes for solid oxide fuel cells. Co-doped Y 0.08 Sr 0.92 TiO 3 −  δ was synthesized via solid-state reaction. The effect of Co-doping on the electrical behavior of Y 0.08 Sr 0.92 TiO 3 −  δ was investigated and a doping mechanism was proposed. Compared with Y 0.08 Sr 0.92 TiO 3 −  δ , the electrical conductivities of Y 0.08 Sr 0.92 Co x Ti 1 −  x O 3 −  δ decrease obviously with increasing Co-doping amount at 25–1000 °C, while the ionic conductivities increase significantly at 500–1000 °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 Y 0.08 Sr 0.92 Co x Ti 1 −  x O 3 −  δ . The decreased electronic conductivity of Y 0.08 Sr 0.92 Co x Ti 1 −  x O 3 −  δ is ascribed to the lowered Ti 3+ concentration, caused by the substitution of Co 3+ . Co-doping increases the oxygen absorption temperature, and thus widens the operation temperature range of doped-SrTiO 3 .