Synthesis and properties of Y-doped SrTiO3 as an anode material for SOFCs

Y-doped SrTiO3 was synthesized via solid-state reaction. The effects of Y-doping on the sinterability and the electrical conductivity of YxSr1−xTiO3 were investigated. Y-doping can increase the sintering activity and the electrical conductivity of SrTiO3 when yttrium amount is less than 0.09 in YxSr1−xTiO3. Excessive yttrium will cause the generation of an insulating phase Y2Ti2O7, which impedes the densification process and decreases the electrical conductivity of YxSr1−xTiO3 material. With the increased temperature, the electrical conductivity of Y-doped SrTiO3 increases first and then decreases gradually, showing a mixed conduction behavior of semi-conductors and metals. The optimized Y0.09Sr0.91TiO3 possesses an electrical conductivity on the order of 32.5–195.8 S cm−1 in the temperature range of 25–1000 °C and being 73.7 S cm−1 at 800 °C in forming gas. The thermal cycling in air does not remarkably affect the electrical conductivity and the conduction behavior of Y0.09Sr0.91TiO3 at high temperatures. Y0.09Sr0.91TiO3 displays a relatively stable electrical conductivity at different oxygen partial pressures and excellent chemical compatibility with YSZ at temperatures lower than 1300 °C.