Smart Processing of Solid Electrolyte Dendrites with Ordered Porous Structures for Fuel Cell Miniaturizations

Solid electrolyte dendrites of yttria stabilized zirconia with spatially ordered porous structures were successfully fabricated for fuel cell miniaturizations by using micro patterning stereolithography. Micrometer order ceramic lattices with the coordination numbers 4, 6, 8 and 12 were propagated spatially in computer graphic space. Aspect ratios of the lattice diameters and lengths were designed between 1.0 and 2.0 to value the porosities in higher levels from 50 to 80 %. On the fabrication process, nanometer sized yttria stabilized zirconia were dispersed in to photo sensitive liquid resins at 30 % in volume fraction to obtain thixotropic slurries. The paste material was spread on a grass substrate with 10 μm in layer thickness by using mechanic knife edge movements, and an ultra violet micro pattern was exposed on the surface to create cross sectional solid layer with 2 μm in part accuracy. After the layer stacking process, the ceramic dispersed resin lattices of 100 μm in diameter were obtained exactly. These composite precursors were dewaxed and sintered at 600 and 1500 °C in an air atmosphere, respectively, and the fine ceramic lattices of 98 % in relative density were created. Gaseous fluid profiles and pressure distributions in the formed ceramic lattices with the various coordination numbers and porosity percents were visualized and analyzed by using finite element method. The fabricated solid electrolytes with the extremely high porosities and wide surface areas are expect to be applied to novel electrodes in the compact fuel cells. The smart processing of the solid electrolytes by utilizing computer aided design, manufacturing and evaluation methods will be demonstrated.