In this work selected cation-ordered perovskite-type anode and cathode materials were investigated in terms of their possible application in intermediate temperature solid oxide fuel cells (IT-SOFC). Their phase composition, oxygen content, chemical diffusion coefficient of oxygen D and surface exchange coefficient K, chemical stability in relation to ceria electrolyte, and stability of the anode material in reducing atmosphere were studied. It was found that Sr0.5Ba1.5CoMoO 6 - δ anode material exhibits Fm-3m symmetry with B-site rock salt-type cation ordering, while YBaCo2O5 + δ cathode material possesses P4/mmm space group with A-site layered-type cation ordering. In the case of SmBa0.5Sr0.5Co 1.5Fe0.5O5 + δ compound, partial (> 70 wt.%) A-site layer-type ordering was observed. Electrical conductivity σ of Sr0.5Ba1.5CoMoO6 - δ anode material is much lower (< 0.1 S·cm- 1), as compared to the studied cathode materials, for which σ > 100 S·cm- 1 in 600-800 °C temperature range was measured. However, in reducing conditions, conductivity of Sr0.5Ba1.5CoMoO6 - δ is significantly enhanced (~ 0.5 S·cm- 1). Chemical stability studies at 1000°C revealed that YBaCo2O5 + δ reacts with Ce0.8Gd0.2O1.9, while SmBa 0.5Sr0.5Co1.5Fe0.5O 5 + δ remains stable. In the case of Sr0.5Ba 1.5CoMoO6 - δ compound, long time annealing in reducing atmosphere of 5 vol.% H2 in Ar at 800°C caused decomposition of the material. Despite poor stability of the anode material in reducing conditions, relatively good performance of constructed H2 | Sr0.5Ba1.5CoMoO6 - δ | Ce 0.8Gd0.2O1.9 | SmBa0.5Sr 0.5Co1.5Fe0.5O5 + δ IT-SOFCs was recorded.
ASJC Scopus subject areas
- 化学 (全般)