SOFC Anode Based on YSZ Pillars

In anode of solid oxide fuel cells (SOFCs), yttria-stabilized zirconia (YSZ), Ni, pore are distributed, and oxygen ions, electrons, H₂ and H₂O gases are transported in each path. And the species chemically reacted each other at the boundaries (triple phase boundaries, TPBs). In the view point of tortuosity, aligned YSZ and Ni particles and TPB are promising structures for a low resistances of matter transporting and their chemical reaction. In our previous work [1], it was proposed and developed that Ni particles were aligned by magnetic field during the drying process after screen-printing Ni/YSZ paste. A second step of low-tortuosity path configuration is completely straight along the specie transporting direction. Because the nominal conductivity of oxygen ion in YSZ is the lowest among the specie (ion, electrons, gas) transportation conductivities, YSZ should be straight preferentially. In this study, we prototyped pillar pattern of YSZ, infiltrated Ni, and investigated the effect of pillar width, height, and surface area of pillar corresponding to TPB length on the generation performance. The YSZ pillars were fabricated by an excimer laser. The figure shows that the width were varied 5, 10, 20, 40 μm, and their trenches were fabricated deeper in wider pillar. The trenches of YSZ pattern were infiltrated by Ni particles. The finer pillar resulted in higher generation performance as also shown in the figure. Furthermore, the electrochemical phenomena was discussed by Lattice-Boltzmann Method simulation.

[1] K. Nagato, N. Shikazono, A. Weber, D. Klotz, M. Nakao, E. Ivers-Tiffée, ECS Trans. 57, 1307-1311 (2013).