Chemical Degradation of the La<sub>0.6</sub>Sr<sub>0.4</sub>Co<sub>0.2</sub>Fe<sub>0.8</sub>O<sub>3−δ</sub>/Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>2−δ</sub> Interface during Sintering and Cell Operation
Mélanie François,
Maria Paola Carpanese,
Olivier Heintz,
Victoire Lescure,
Davide Clematis,
Lionel Combemale,
Frédéric Demoisson,
Gilles Caboche
Affiliations
Mélanie François
Laboratoire Interdisciplinaire Carnot de Bourgogne, FCLAB, ICB-UMR6303, CNRS—Université de Bourgogne Franche-Comté, 9 Avenue Savary, BP47870, CEDEX, 21078 DIJON, France
Maria Paola Carpanese
Department of Civil, Chemical and Environmental Engineering (DICCA)—Università Degli Studi di Genova, Via Montallegro 1, 16145 Genova, Italy
Olivier Heintz
Laboratoire Interdisciplinaire Carnot de Bourgogne, FCLAB, ICB-UMR6303, CNRS—Université de Bourgogne Franche-Comté, 9 Avenue Savary, BP47870, CEDEX, 21078 DIJON, France
Victoire Lescure
Laboratoire Interdisciplinaire Carnot de Bourgogne, FCLAB, ICB-UMR6303, CNRS—Université de Bourgogne Franche-Comté, 9 Avenue Savary, BP47870, CEDEX, 21078 DIJON, France
Davide Clematis
Department of Civil, Chemical and Environmental Engineering (DICCA)—Università Degli Studi di Genova, Via Montallegro 1, 16145 Genova, Italy
Lionel Combemale
Laboratoire Interdisciplinaire Carnot de Bourgogne, FCLAB, ICB-UMR6303, CNRS—Université de Bourgogne Franche-Comté, 9 Avenue Savary, BP47870, CEDEX, 21078 DIJON, France
Frédéric Demoisson
Laboratoire Interdisciplinaire Carnot de Bourgogne, FCLAB, ICB-UMR6303, CNRS—Université de Bourgogne Franche-Comté, 9 Avenue Savary, BP47870, CEDEX, 21078 DIJON, France
Gilles Caboche
Laboratoire Interdisciplinaire Carnot de Bourgogne, FCLAB, ICB-UMR6303, CNRS—Université de Bourgogne Franche-Comté, 9 Avenue Savary, BP47870, CEDEX, 21078 DIJON, France
A complete cell consisting of NiO-Ce0.8Sm0.2O3−δ//Ce0.8Sm0.2O3−δ//(La0.6Sr0.4)0.95Co0.2Fe0.8O3−δ elaborated by a co-tape casting and co-sintering process and tested in operating fuel cell conditions exhibited a strong degradation in performance over time. Study of the cathode–electrolyte interface after cell testing showed, on one hand, the diffusion of lanthanum from (La0.6Sr0.4)0.95Co0.2Fe0.8O3−δ into Sm-doped ceria leading to a La- and Sm-doped ceria phase. On the other hand, Ce and Sm diffused into the perovskite phase of the cathode. The grain boundaries appear to be the preferred pathways of the cation diffusion. Furthermore, a strontium enrichment was clearly observed both in the (La0.6Sr0.4)0.95Co0.2Fe0.8O3−δ layer and at the interface with electrolyte. X-ray photoelectron spectroscopy (XPS) indicates that this Sr-rich phase corresponded to SrCO3. These different phenomena led to a chemical degradation of materials and interfaces, explaining the decrease in electrochemical performance.
