Stability study of metal-supported solid oxide fuel cell using diesel reformate

Abstract

This thesis discusses about metal-supported solid oxide fuel cell (SOFC) operation using diesel reformate. SOFC has great possibilities to make fuel cell system because of high efficiency and fuel flexibility. The majority of SOFC development has focused on ceramic-supported cells: anode-supported cells (ASCs), electrolyte-supported cells (ESCs), or cathode-supported cells (CSCs). In the cases of ASC, ESC and CSC, there are several problems remained such as mechanical strength, thermal cycling and sealing efficiency. New design of SOFC was suggested to solve those challenges, which are metal-supported cells (MSCs). MSCs have been recognized as a high-potentially commercializable technology due to their high mechanical strength and excellent sealing efficiency. Diesel is a representative of heavy hydrocarbon fuels and has many advantages, such as high hydrogen density and well infrastructure for refueling. These advantages made diesel better for various applications, such as transportation and military. Diesel reforming is also very competitive to use for SOFC as fuel processing. Diesel-driven metal-supported SOFC has some merits, which the system can be portable and have high stability and durability. The system can be applied to auxiliary power units (APUs) for transportation and military power generator. However, there have not been studied metal-supported SOFC coupled with diesel reformer. Therefore, the issues of metal-supported SOFC operation using diesel reformate were discussed, and the possible solutions were suggested in this thesis. Metal-supported cells were successfully fabricated from button size to $10vxv10 cm^2$ large sizes using high temperature sinter-joining process. The metal-supported cells show high electrochemical performance with hydrogen fuel as well as stable long-term performance. However, there was a serious problem with long-term operation when diesel reformate was supplied as fuel. The main reason of performance degradation was meta...