LAUSR

Abstract The electrochemical properties of the composite electrodes of LaNi0.6Fe0.4O3−δ-Ce0.9Gd0.1O1.95 in various compositions were measured by electrochemical impedance spectroscopy as a function of temperature and p(O2). The enhancement of area-specific conductivity, σE, was found higher than that of the single-phase porous LaNi0.6Fe0.4O3−δ electrode. σE greatly depends on their volume ratio, where σE increases with the increase of the volume fraction of Ce0.9Gd0.1O1.95 phase up to 50%. Above 50% of the volume ratio, σE decreases which could be due to the loss of its surface area density and connectivity between LaNi0.6Fe0.4O3−δ particles. The enhancement degree of σE was evaluated using the transmission line model for the porous-mixed ionic and electronic electrodes. The calculated model is close to the measured σE, showing that the enhancement of σE is not only because of the enhancement of ionic conducting pathways but also possibly due to the decrease of the surface reaction resistivity upon contact with the Ce0.9Gd0.1O1.95.