Interaction between Fe-Cr metallic interconnect and (La,Sr) MnO ₃/YSZ composite cathode of solid oxide fuel cells

The interaction between a chromia-forming alloy interconnect and (La,Sr) MnO3 Y2 O3 - ZrO2 (LSM/YSZ) and Gd-doped CeO2 (GDC)-impregnated LSM electrodes is investigated under solid oxide fuel cell operating conditions. LSM/YSZ and GDC-impregnated LSM composite electrodes show much higher electrochemical activity and performance stability in comparison to that of pure LSM. In contrast to that on the pure LSM electrode, there is no preferential deposition of Cr species at the electrode and electrolyte interface region for the reaction on the LSM/YSZ composite electrode with high YSZ content (30 wt %) and a 1.6 mg cm-2 GDC-impregnated LSM composite electrode. The amount of Cr deposits is also much smaller in comparison to that on the pure LSM electrode. The reason for the significantly reduced Cr deposition in the LSM composite cathodes is most likely due to the decrease of Mn2+ ions generated under cathodic polarization, which leads to the significant reduction in the nucleation and grain growth reaction for the Cr deposition. The results demonstrate that LSM composite and GDC-impregnated LSM electrodes have high tolerance toward Cr species.