Preparation and electrical behavior study of the ceramic interconnect La_0.7Ca_0.3CrO_3-δ with CeO₂-based electrolyte Ce_0.8Sm_0.2O_1.9

Based on the conventional interconnect La_0.7Ca_0.3CrO_3-δ, a novel ceramic interconnect for intermediate temperature solid oxide fuel cells was developed. In the air, the electrical conductivities of La_0.7Ca_0.3CrO_3-δ + 5%Ce_0.8Sm_0.2O_1.9 at 600, 700 and 800 °C were 96.7, 146.3 and 687.8 S cm^-1, respectively, which increased significantly as compared with La_0.7Ca_0.3CrO_3-δ under the same conditions. Similarly, in pure hydrogen, La_0.7Ca_0.3CrO_3-δ + 3%Ce_0.8Sm_0.2O_1.9 possessed the maximal electrical conductivities which were 4.2, 5.3 and 7.1 S cm^-1, respectively at 600, 700 and 800 °C. The crystal structures of La_0.7Ca_0.3CrO_3-δ, La_0.7Ca_0.3CrO_3-δ + 5%Ce_0.8Sm_0.2O_1.9 and La_0.7Ca_0.3CrO_3-δ + 10%Ce_0.8Sm_0.2O_1.9 were single phase with hexagonal symmetry, cubic phase plus some doped ceria impurity and orthorhombic phase plus some doped ceria impurity, respectively. The difference between the crystal structures may account for the difference between the electrical conductivities. The electrical conductivities and sinterability of La_0.7Ca_0.3CrO_3-δ were increased by introducing Ce_0.8Sm_0.2O_1.9, whereas the other properties were not influenced.