No abstract

“Reaction-sintered” powder processing is a new method for low-cost production of yttria-stabilized zirconia (YSZ). Developed by CoorsTek, Inc., reaction-sintered 8YSZ powders may prove to be a low-cost alternative to conventional ceramic powders used in solid oxide fuel cells (SOFC’s). However, the performance of fuel cells fabricated using reaction-sintered 8YSZ powders needs to be quantitatively compared to the conventional 8YSZ powders. In this study, we present results of such a comparison by evaluating both planar anode supports and tubular SOFC’s fabricated using reaction-sintered and conventional 8YSZ powders. Comparisons between material sets were conducted to compare cell morphology and composition, in addition to a number of different SOFC-performance metrics, including gas transport, fuel-conversion and power density. Experimental results show that the performance of SOFCs fabricated using reaction-sintered 8YSZ is comparable to cells fabricated with conventional 8YSZ powders.

Biofuels are receiving significant interest as a source for sustainable, locally produced hydrocarbon fuels. While solid-oxide fuel cells (SOFCs) can operate efficiently on biomass fuel streams, their use can prove problematic if process conditions are not carefully monitored, as carbon-deposit formation presents a significant risk. In this study, we examine the chemistry and transport processes underway when SOFC anodes are exposed to ethanol-steam mixtures. Through use of a unique Separated-Anode Experiment, this study decouples anode chemistry processes from charge-transfer, cathode-activation, and other electrochemical processes in an effort to focus on ethanol decomposition in SOFC environments. Experiments are combined with numerical simulations that include Dusty-Gas transport modeling within the anode pore structure, and elementary, multi-step heterogeneous and homogeneous chemical kinetics mechanisms representing fuel conversion within the anode. Process windows for deposit-free operation are postulated, and alternate anode architectures that minimize the risk of deposit formation are discussed.