Electrochemical and morphological characterizations of La2⿿xNiO4±d (x = 0.01, 0.02, 0.03 and 0.05) as new cathodes materials for IT-SOFC

Abstract

A new IT-SOFC (Intermediate Temperature Oxide Fuel Cell) cathode material, La2⿿xNiO4±δ (x=0.01, 0.02, 0.03 and 0.05), was tested along with the electrolyte material yttria-stabilized zirconia (YSZ). The low deficit materials have good electrochemical properties. L2NO has shown the lowest resistance values meanwhile L1NO has shown the lowest energy activation. Particle size decrease according to the percentage of deficiency as increased interaction force between atoms causes shrinkage of the crystal lattice. In addition, porosity is reduced. Nevertheless this phenomenon adversely affects the electrochemical properties of the material by increasing its polarization resistance. That was observed in the case of materials whose deficiency varies between 3 and 5%. The mixed conducting materials were prepared by the citrate method. They were characterized by SEM and XRD while their electric properties were studied by impedance spectroscopy. Eventually improvements in the electrochemical properties of the cathode are certainly due to the morphological properties of materials.