Formation of La0.8Sr0.2MnO3 films as SOFC cathodes by electrophoretic deposition

概要

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La0.8Sr0.2MnO3 (LSM) cathode films for a solid oxide fuel cell (SOFC) were formed on a solid electrolyte sheet using the electrophoretic deposition (EPD) technique. The EPD process was undertaken in methanol suspensions containing LSM particles with different mean particle sizes. The zeta potentials of the LSM dispersions in methanol tended to decrease with increased sintering temperature during powder preparation. The morphology of the cathodic films was significantly dependent on the mean particle size and the grain sizes in the films after sintering at 1100°C were in the order of LSM600 > LSM1000 > LSM800, with corresponding cathodic performance in the order of LSM800 > LSM1000 > LSM600. The morphology of the LSM 800 films varied with the DC voltage applied during the EPD process (7.5 and 15 V), and a more densely deposited phase with finer pores was achieved with lower applied voltage. Increase in applied voltage tended to induce particle growth; therefore, the film applied at low voltage exhibited the highest cathodic performance. The cathodic performance was not dependent on the film thickness in the range between 5 and 15 µm, which implies that the LSM800 film was sufficiently porous to provide a suitable rate of oxygen gas diffusion.