Ce0.8Gd0.2O2-δ protecting layers manufactured by physical vapor deposition for IT-SOFC

Anode-supported Solid Oxide Fuel Cells (SOFCs) built with La0.58Sr0.4Fe0.8Co0.2O3 (-) (delta) (LSCF) as cathode material exhibit a high electrochemical performance at low temperatures. However, these LSCF perovskites are chemically incompatible with the YSZ electrolyte, reacting to SrZrO3 which acts as an inhibitor for ion conductivity. Therefore, an interlayer between electrolyte and cathode is needed to prevent Sr2+ migration towards the electrolyte. Among the materials we could imagine for this purpose, gadolinium doped ceria, e.g. Ce0.8Gd0.2O2 (- delta) (CGO) shows a good performance. The electrochemical performance of these cells depends on the microstructure of the CGO layer. The deposition method plays an important role for the microstructure of the layer. The deposition methods screen printing and physical vapor deposition were compared. Among the physical vapor deposition methods, the magnetron sputtering seems to be the more accurate technology to produce nearly dense layers with efficient Sr2+ retention. The correlation between the CGO layer microstructure and the performance of the cell and the Sr2+-retention was studied. (C) 2007 Elsevier B.V. All rights reserved.