Slip-cast and hot-solution infiltrated porous yttria stabilized zirconia (YSZ) supported tubular fuel cells
Hot solution infiltration was investigated as a flexible and rapid method to incorporate anode and cathode components into fully sintered, porous ceramic tubular templates for use as solid oxide fuel cells (SOFC). Composed of either a porous 8 mol% yttria-stabilized zirconia (YSZ) or 5 wt% NiO–YSZ support structure, a thin Ni–YSZ anode functional layer and an outer ca. 10 μm dense YSZ electrolyte, closed end tubes were first hot solution (ca. 100 °C) infiltrated on the inside with NiO–SDC (Sm0.2Ce0.8O1.9) to serve as the anode. Cathodes were either LSM (nominally La0.8Sr0.2MnO3+δ) infiltrated into a thin porous YSZ layer on the outer electrolyte surface, or an LSCF–GDC composite (Gd0.1Ce0.9O1.95–La0.6Sr0.4Co0.2Fe0.8O3−δ) on a thin GDC buffer layer. Although hot solution infiltration of the Ni, Ce and Sm salts into the anode support structure did not result in complete penetration (with the Ni contents in the tube wall ranging between 4 and 10 vol.%), well-sealed full cells produced power densities as high as 275, 196 and 153 mW cm−2 at 800, 750 and 700 °C, respectively. Hot solution infiltration of active SOFC electrode materials is thus shown to be a very flexible approach for the evaluation of their performance.