New Fabrication Techniques for Micro-Tubular Hollow Fiber Solid Oxide Fuel Cells

Abstract

A novel combination of phase inversion and electrophoretic deposition was used in the fabrication of anode supported micro tubular (hollow fiber) solid oxide fuel cells (MT-HF-SOFCs). The phase inversion process was used to produce ca. 240 μm thick, highly porous 60 wt. % NiO-40 wt. % yttria-stabilised zirconia (YSZ) hollow fiber anode precursors. The electrophoretic deposition process was then used to apply ca. 40 μm thick, particulate YSZ electrolyte layers onto the unsintered NiO-YSZ HFs from an ethanol suspension at an applied electric field of ca. 0.22 kV cm-1. The YSZ-coated NiO-YSZ HFs were sintered at 1500 oC for twelve hours. Dispersions of YSZ-LSM particles were then painted on top of the electrolyte layer, as ‘graded’ YSZ-LSM porous cathode precursors that were sintered at 1200 oC for three hours. The fabrication process was completed by winding silver wire current collectors spirally round the cathodes and through the lumen of the fibers to enable current collection from the anodes. Single MT-HF-SOFCs delivered peak power densities of 0.20, 0.18 and 0.14 W cm-2 at 800, 750 and 700 oC, respectively, with flow rates of 15 cm3 min-1 H2 (97% H2-3% H2O) and 30 cm3 min-1 of air.