The Effect of Anode Thickness on the Performance of Anode-Supported Solid Oxide Fuel Cells

Abstract

Anode-supported cells comprising a three layer structure of a porous composite cathode of Sr-doped LaMnO3 (LSM) + yttria-stabilized zirconia (YSZ); a thin, dense YSZ electrolyte; and a porous Ni + YSZ anode were fabricated. The anode thickness was varied between similar to 1.04 and similar to 3.86 mm. The YSZ electrolyte thickness was similar to 10 mu m and the LSM + YSZ cathode thickness was similar to 50 mu m. The cells were tested at 800 degrees C with humidified hydrogen as the fuel and air as the oxidant. The voltage (V) vs, current density (i) traces were nonlinear; concave-up (d(2)V/di(2) greater than or equal to 0) at low current densities and convex-up (d(2)V/di(2) less than or equal to 0) at high current densities. The maximum power density for a cell with an anode thickness of similar to 1.04 mm was similar to 1.9 W/cm(2) and that for a cell with an anode thickness of similar to 3.86 mm was similar to 1.1 W/cm(2). The measured short circuit current densities were similar to 6.35 A/cm(2) for a cell with an anode thickness of similar to 1.04 mm and similar to 3.56 A/cm(2) for a cell with an anode thickness of similar to 3.86 mm. The V vs. i traces were fitted to a previously developed theoretical model. The present work shows that anode-supported cells can be made with a relatively thick and rugged anode while still exhibiting an excellent power density at a temperature of 800 degrees C.