Interfaces and Durability for Different LSCF/CGO/YSZ Systems for IT-SOFC

Abstract

Ageing investigations of LSCF/CGO/YSZ systems were performed at 700°C in air at OCV up to 530h with different thicknesses of CGO layer (0, 0.11, 0.45, 1.1 and 2 µm). After 530 h, a low series resistance variation is observed and becomes weaker with CGO layer due to a better contact. The polarization resistance evolution is strongly reduced when the CGO layer is added, and the minimum is observed with a CGO thickness of only 0.11 µm. The increase of the polarisation resistance was related to the high frequency contribution which corresponds to the degradation of the ionic transfer at the electrode / electrolyte interface. X-ray microanalyses have shown the diffusion and segregation of Sr at this interface only in the sample without CGO layer.