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PERFORMANCE OF Ni/CEO2/YSZ SOFC ANODES WITH CARBONACEOUS FUELS

dc.contributor.advisorJackson, Gregory Sen_US
dc.contributor.authorPatel, Siddharthen_US
dc.date.accessioned2010-02-19T06:45:33Z
dc.date.available2010-02-19T06:45:33Z
dc.date.issued2009en_US
dc.identifier.urihttp://hdl.handle.net/1903/9876
dc.description.abstractThis 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.titlePERFORMANCE OF Ni/CEO2/YSZ SOFC ANODES WITH CARBONACEOUS FUELSen_US
dc.typeThesisen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.contributor.departmentMechanical Engineeringen_US
dc.subject.pqcontrolledEngineering, Mechanicalen_US
dc.subject.pquncontrolledbutaneen_US
dc.subject.pquncontrolledcellen_US
dc.subject.pquncontrolledceriaen_US
dc.subject.pquncontrolledfuelen_US
dc.subject.pquncontrolledoxideen_US
dc.subject.pquncontrolledsoliden_US


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