Novel Ceramic Anode Material Research and Development for Fuel Flexible and Reversible Operation of a Solid Oxide Fuel Cell.

摘要

Solid oxide fuel cell (SOFC) technology is an attractive, emerging alternative for clean electrical power generation. Motivated by the potential to advance SOFC to a more accessible technology, this dissertation is focused upon the SOFC materials research, aimed to contribute to cost reduction, fuel flexible operation and versatile system integration and reversible operation of an SOFC system.;This dissertation describes the research and development of novel ceramic anode materials for fabrication, fuel flexible and reversible operation of a solid oxide fuel cell. Properties of novel Yttrium-doped SrTiO3 (Sr0.86Y0.08TiO3, SYT) material for use as anode in an anode-supported SOFC have been characterized. Positive electrode, electrolyte, and negative electrode (PEN) structures have been fabricated via cost-effective manufacturing processes. A tape casting process has been utilized to fabricate SYT-based anode substrates, porous and homogeneous SYT-based anode substrates have been fabricated. Ceramic processing methods utilized in this dissertation are not only adequate to fabricate lab scale button cells, but also can be scaled to fabricate large scale SOFC planar cells. Conductivities of SYT and SYT-YSZ composite are examined and the effects of preparation conditions on electrical properties of SYT are discussed. Overall performance of SYT-YSZ anode-supported cells have been tested and evaluated. Cell performance is compared using both dry/wet hydrogen and methane as fuel at 800°C. The reversible operation of an SYT-YSZ anode-supported cell is also tested. The results indicate that SYT-based anode material has relatively poor performance and higher anode overpotential compared to a traditional Ni-YSZ anode. A two-dimensional isothermal mathematical model of an SYT ceramic based anode-supported solid oxide fuel cell has been developed and verified using experimental results. Simulation results provide important information to identify the major sources of the polarization losses and to determine possible explanations for the fast degradation observed. Life cycle analysis was performed on anode substrate manufacturing and the water tape casting has been proved to require the lowest energy inputs and have the lowest emissions. The SYT-based anode-supported planar SOFC system consumes less energy and thus produces less emissions than a Ni-YSZ based anode-supported planar SOFC system.