Anode Supported SOFC With GDC Barrier Layer Deposited by Aerosol Deposition Method

In this study, a thin (less than 1 micrometer) interlayer of gadolinia doped ceria (GDC) was applied by aerosol deposition (AD) process between YSZ electrolyte and LSCF-GDC composite cathode. The GDC interlayer was co-fired with the cathode without an additional heat treatment step. Performance of the cells with the GDC layer was evaluated with small button type cells. The results show that the GDC layer was dense enough to successfully prevent the formation of SrZrO₃ layer after cathode heat treatments under 1100°C. Electrochemical performance of the cells largely depended on the sintering temperatures. Maximum power densities were 1.0 ± 0.1 W/cm² at 750°C after sintering at the temperatures between 1000°C and 1060°C. Through SEM and TEM study, solid solution layer at the interface of GDC layer and YSZ layer was found in the specimen after sintering at 1000°C and SrZrO3 layers on both sides of the GDC layer after heat treatment at 1100°C. These layers contributed to the poor performance of the cells sintered at over 1080°C. Therefore, the temperatures for cathode sintering have to be precisely controlled to get the best performance. AD process requires week vacuum and takes only couple minutes to finish deposition. This presentation also shows scaling up the ADM process to 320 mm × 220 mm planar cells for dozens kW stack application at the Research Institute of Industrial Science and Technology (RIST) in Korea. Long term operation tests for the large cells are now on process.