Direct oxidation solid oxide fuel cell: Aspects of anode performance optimization.

摘要

I have examined the impact of high fuel utilization and anode catalyst stability for Cu-based anodes in solid oxide fuel cells (SOFC). First, the performance of SOFC with Cu-ceria-YSZ anodes was studied in n-butane at 973 K as a function of fuel conversion. Conversion led to dilution of the fuel which resulted in a significant decrease in performance at higher fuel conversions. I demonstrated that the inclusion of a steam-reforming catalyst within the anode compartment of direct-oxidation SOFC improved performance at high fuel utilization.; The performance of a Cu-CeO2-YSZ SOFC was compared to a conventional SOFC with Ni-YSZ anode while operating on H2, CO, and syngas fuels. Cells with Cu-CeO2-YSZ anodes exhibit similar performance when operating on H2 or CO fuels, while cells with Ni-YSZ anodes exhibited substantially lower performance when operating on CO compared to H2. My work demonstrated that dilution of H2 by H2O has little effect on the kinetics of H2 oxidation on both the Cu-CeO 2-YSZ and Ni-YSZ anodes.; In addition, I have investigated the thermal stability of the anode catalyst, ceria, was using thin ceria films supported on YSZ. Special attention was given to the interactions between ceria and YSZ under high temperature treatments in reducing and oxidizing environments. My results have shown that ceria films on YSZ are highly mobile at relatively moderate temperatures and their morphology depends on the gas environment to which they have been exposed. Studies with alpha-Al2O3 assisted in clarifying the role of the substrate in the treatment effects on ceria.