Structural and sintering characteristics of the La2Ni1−xCoxO4+δ series

The solid solution, La2Ni1−xCoxO4+δ (0.00≤x≤1.00), based on the K2NiF4 structure was synthesised and studied for potential use as cathodes in solid-oxide fuel cells. A structural phase transition was observed with increasing cobalt substitution, between x=0.50 and 0.60 from tetragonal to orthorhombic symmetry. An apparent correlation between the area specific resistance and microstructural properties has been found for materials produced using both conventional and microwave heating. The difference in microstructure for samples prepared by these two techniques persists even after firing on CGO and LSGM pellets at 950 °C in air for 2 weeks.