Interaction between La(Sr)FeO3 SOFC cathode and YSZ electrolyte

Anode-supported yttria-stabilized zirconia (YSZ) solid oxide fuel cells utilizing a Sr-doped LaFeO3 (LSF) cathode show improved performance with the incorporation of a Sm-doped CeO2 layer between the cathode and YSZ electrolyte. Detailed X-ray diffraction (XRD) analysis of LSF–YSZ reaction mixtures indicates no strontium or lanthanum zirconate formation between these materials even at 1400 °C. However, a significant shift in the LSF diffraction peaks is readily apparent and corresponds to a unit cell volume expansion. The most likely scenario for the change in volume is considered to be the incorporation of Zr4+ cations in the perovskite structure. The presence of the Zr cations subsequently results in reduced electrical conductivity of the cathode, potentially explaining the need for the aforementioned ceria interlayer.