PrBaCo2O6-δ - Ce0.8Sm0.2O1.9 Composite Cathodes for Intermediate Temperature Solid Oxide Fuel Cells

The single phase double perovskite PrBaCo₂O_6-δ and composites (100‑y) PrBaCo₂O_6‑δ ‑ y Ce_0.8Sm_0.2O_1.9 (y = 10 ‑ 30 wt.%) were investigated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). The chemical compatibility, thermal expansion behavior, DC conductivity and electrochemical performance of these materials were studied. The results on chemical compatibility showed no reaction between PrBaCo₂O_6-δ and Ce_0.8Sm_0.2O_1.9 electrolyte even at temperature as high as 1200 °C. The average thermal expansion coefficient and overall conductivity of (100‑y) PrBaCo₂O_6‑δ ‑ y Ce_0.8Sm_0.2O_1.9 (y = 10 ‑ 30 wt.%) composite materials were shown to decrease with increasing content of Ce_0.8Sm_0.2O_1.9 in the composite whereas the polarization resistance was found to increase somewhat at the same time. Although the thermal expansion coefficient of the composite cathodes remains too high as compared to that of the electrolyte, the values of their total conductivity and electrochemical activity meet requirements for successful application of such cathode materials in IT-SOFCs.