Y-substituted SrTiO3–YSZ composites as anode materials for solid oxide fuel cells: Interaction between SYT and YSZ

Donor-substituted SrTiO3 ceramic materials were investigated as the anodes of solid oxide fuel cells (SOFCs). Sr0.89Y0.07TiO3−δ (SYT) samples with good electrical conductivity and redox stability were prepared. The thermal and chemical expansions of SYT are both compatible with YSZ electrolyte. Half cells consisting of a flat anode substrate and an electrolyte layer with outer dimensions of 5 cm × 5 cm were fabricated, Ni particles were infiltrated on the pore walls within the ceramic anode framework, and the redox stability of the half cell was tested by He leakage tests after redox cycling. Ti diffusion but no Sr migration was found between the anode and electrolyte layers. Sr0.895Y0.07TixO3±δ (x = 1.00–1.20)–YSZ composites with a volume ratio 2:1 were prepared to investigate the influences of this interdiffusion between YSZ and SYT materials. The results indicate that the conductivity of SYT decreases because of the Ti diffusion, and a small amount of Ti excess can solve this problem.