Thermochemical Stability and Polarization Resistance of La(Ni0.6Fe0.4)O3 Cathode

Abstract

Polarization resistance of LaNi 0.6 Fe 0.4 O 3 (LNF) cathode has been investigated in relation to its electrical conductivity and thermochemical stability. Electrochemical properties of a solid oxide fuel cell using LNF as the cathode were compared to those using La 0.8 Sr 0.2 MnO 3 (LSM). Temperature dependence of the cathodic polarization resistance is discussed in terms of its thermochemical stability. The electrical conductivity of bulk LNF sample was measured with the four-probe DC method at different oxygen partial pressures. Phase identification for the LNF powder samples treated at 900 o C in the atmosphere of oxygen and argon was studied with time dependency of heat treatment by X-ray diffraction analysis. Although the rhombohedral crystal structure of the starting phase was maintained, the electrical conductivity of LNF sensitively changed with the partial pressure of oxygen.