Effect of A-site stoichiometry on phase stability and electrical conductivity of the perovskite Las(Ni0.59Fe0.41)O3−δ and its compatibility with (La0.85Sr0.15)0.91MnO3−δ and Zr0.85Y0.15O2.925

To investigate the influence of A-site stoichiometry on phase stability and electrical conductivity of the perovskite based series Las(Ni0.59Fe0.41)O3−δ for cathode current collection in solid oxide fuel cells, X-ray diffraction and DC electrical conductivity studies were performed on samples, prepared by the glycine nitrate combustion method. The chemical compatibility of La0.99(Ni0.59Fe0.41)O3−δ with the cathode material (La0.85Sr0.15)0.91MnO3−δ and the electrolyte Y2O3-doped ZrO2 (8 mol%) was likewise studied by X-ray diffraction and scanning electron microscopy. Small deviations (∼1 at.%) in the A-site stoichiometry of the perovskite did not result in significant change to the electrical conductivity. Extensive reaction between La0.99(Ni0.59Fe0.41)O3−δ and 8 mol% Y2O3 doped ZrO2 after sintering was observed by X-ray diffraction. Reaction between La0.99(Ni0.59Fe0.41)O3−δ and (La0.85Sr0.15)0.91MnO3−δ resulted in a single perovskite material when the compounds were co-sintered. The interface between a screen-printed layer of La0.99(Ni0.59Fe0.41)O3−δ and a layer of Ce0.9Gd0.10O3−δ/(La0.85Sr0.15)0.91MnO3−δ composite has been investigated and the extent of the reaction zone determined by energy dispersive X-ray spectroscopy.