PERFORMANCE OF Ni/CEO2/YSZ SOFC ANODES WITH CARBONACEOUS FUELS
| dc.contributor.advisor | Jackson, Gregory S | en_US |
| dc.contributor.author | Patel, Siddharth | en_US |
| dc.contributor.department | Mechanical Engineering | en_US |
| dc.contributor.publisher | Digital Repository at the University of Maryland | en_US |
| dc.contributor.publisher | University of Maryland (College Park, Md.) | en_US |
| dc.date.accessioned | 2010-02-19T06:45:33Z | |
| dc.date.available | 2010-02-19T06:45:33Z | |
| dc.date.issued | 2009 | en_US |
| dc.description.abstract | This study explores the impact of ceria incorporation into Ni/YSZ cermet anode support layers on the performance of button-cell solid oxide fuel cells operating with syngas and n-butane/steam fuel feeds. Ceria is incorporated into the porous anode support by co-firing ceria powders with NiO, YSZ, and graphite pore formers. Comparison of the performance with and without the co-fired ceria indicated improvements for operation with doped ceria for both syngas (by almost 20% higher power density) and direct n-butane/steam feeds (by over 25% higher power density). For initial cell performance, ceria addition to the support layer offered improved performance at high current densities with syngas suggesting that ceria enhanced water-gas-shift reactions, thereby increasing H2 availability for more effective electrochemical oxidation in the functional layer. For longer-term testing with direct-butane feeds, ceria doped cells not only showed better performance, but also indicated suppression of carbon deposition thus improving long term operability. Ex situ characterization of the ceria-doped anodes using SEM and Raman spectroscopy indicated that ceria addition helped the anodes maintain their structural integrity. To better understand the experiments, a previous through-the-MEA 1-D model has been updated and used with C-H-O microkinetics for Ni/YSZ anodes to characterize the experimentally observed cell performance. The model was enhanced by developing a leakage mechanism to account for leakage through the electrolyte and by incorporating non-isothermal effects to account for temperature gradients due to endothermic internal reforming and exothermic oxidation within the anode layers. Studies with internal methane reforming in a Ni/YSZ anode showed that the non-isothermal effects in 1-D button cell experiments are very small. This through-the-MEA model was used to fit experimental data and provided a basis for assessing key micro-structural parameters for the Ni/YSZ cells tested in this study. The model fits with syngas at various compositions provided a basis for assessing the most sensitive micro-structural parameters on the fuel cell performance such as anode support layer porosity and tortuosity. | en_US |
| dc.identifier.uri | http://hdl.handle.net/1903/9876 | |
| dc.subject.pqcontrolled | Engineering, Mechanical | en_US |
| dc.subject.pquncontrolled | butane | en_US |
| dc.subject.pquncontrolled | cell | en_US |
| dc.subject.pquncontrolled | ceria | en_US |
| dc.subject.pquncontrolled | fuel | en_US |
| dc.subject.pquncontrolled | oxide | en_US |
| dc.subject.pquncontrolled | solid | en_US |
| dc.title | PERFORMANCE OF Ni/CEO2/YSZ SOFC ANODES WITH CARBONACEOUS FUELS | en_US |
| dc.type | Thesis | en_US |
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