One of the considered solutions to avoid the reactivity between LSCF cathode and YSZ electrolyte is the intercalation of a CGO buffer layer. A study of the interfacial reactivity by XRD and by ToF-SIMS between CGO, by ESD, and YSZ has shown that an heat treatment above 1100 °C in air leads to the chemical degradation of the CGO layer leads to the formation of a solid solution. An ageing investigation of LSCF/CGO/YSZ half cell was performed for different CGO layer thicknesses coated by DC magnetron sputtering from 0.11 to 2 µm, by electrochemical impedance spectroscopy at 700 °C in air at OCV. EIS measurements have shown that the thickness of this coating has a strong effect on the electrical properties of these systems. The introduction of a thin CGO buffer layer has lead to the decrease of the initial value of the series resistance and to the reduction of the LSCF electrode degradation. This degradation electrode is due to the diffusion of Sr at the LSCF/YSZ interface as shown by microanalyses X.
