Evaluation of ScSZ Electrolyte Added with Ga₂O₃ and Fabrication of Anode-Supported SOFC

抄録

The effects of Ga₂O₃ addition into 10mol% Sc₂O₃-stabilized zirconia (10ScSZ) on the phase transformation, oxide-ion conductivity and densification behavior were studied for the application of solid electrolyte of solid oxide fuel cell(SOFC). The addition of 0.5mol% Ga₂O₃ into10ScSZ was found to stabilize the cubic structure down to room temperature, although 10ScSZ without additives showed the phase transition from cubic to rhombohedral at 650^oC or below, leading to poor oxide-ion conductivity. The 10ScSZ with 0.5mol% Ga₂O₃ (10ScSZ0.5Ga)showed conductivity of 0.31S/cm at 1000^oC. The densification behavior was enhanced by the addition of Ga₂O₃, and fully densified body was obtained at 1300^oC. 10ScSZ0.5Ga thus obtained was evaluated as a solid electrolyte for anode-supported SOFC cell where Ni-YSZ, La_0.6Sr_0.4Co_0.2Fe_0.8O₃(LSCF) and Sm-doped CeO₂ were used as anode, cathode and barrier layer between 10ScSZ0.5Ga and LSCF respectively. The maximum power density of 1.0W/cm² was obtained at 800^oC operation.