Tsutomu NAKAMURA

Characterization of La(Ni,Fe)O3 as a new cathode for solid oxide fuel cells

Supervisor: Kazunori SATO


Substitution of iron for nickel in LaNiO3 stabilizes the perovskite phase with an increase in the electronic conductivity. The La(Ni,Fe)O3 cathode combined with a 10 mol%Sc2O3-1 mol%Al2O3-89 mol%ZrO2 electrolyte showed a higher solid-oxide-fuel-cell (SOFC) performance than the La0.6Sr0.4MnO3 cathode. The crystal phase and microstructure of the La(Ni,Fe)O3 cathode were stable for the fuel cell operation at least up to approximately 800 degrees Celsius. Phase stability and reactivity for La(Ni,Fe)O3 with yttria-stabilized zirconia were investigated at 800-1100 degrees Celsius by X-ray diffraction and scanning electron microscopy. An appreciable amount of La2Zr2O7, which degrades the SOFC performance, was formed approximately above 1000 degrees Celsius.�@The cathodic polarization resistance of LaNi0.6Fe0.4O3 was approximately half as much as�@that of La0.6Sr0.4MnO3. This decrease can be attributed to a high-electronic conductivity of LaNi0.6Fe0.4O3 and its ability to transfer the oxygen from the gas phase to the electrolyte.