Visualization of oxide ionic diffusion at SOFC cathode/electrolyte interfaces by isotope labeling techniques

The depth profiles of secondary ion mass spectrometry (SIMS) have been applied to analyze the distribution of 18O and metal oxide ions precisely at La0.6Sr0.4Co0.2Fe0.8O3 − d/Gd0.1Ce0.9O2 − x (GDC)/Y0.15Zr0.85O2 − y (YSZ) interfaces. 18O concentration peak was identified only under cathodic polarization with a constant current density of 0.071 A cm− 2 at 973 K under 18O2 atmosphere. The 18O peak position was corresponded to the Sr condensed zone where SrZrO3 was formed at the GDC/YSZ interfaces. The SrZrO3 formation and the 18O concentration profile pile-up are correlated to each other.