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

Anode-supported cells comprising a three layer structure of a porous composite cathode of Sr-doped LaMnO 3 (LSM) + yttria-stabilized zirconia (YSZ); a thin, dense YSZ electrolyte; and a porous Ni + YSZ anode were fabricated. The anode thickness was varied between ∼1.04 and ∼3.86 mm. The YSZ electrolyte thickness was ∼10 pm and the LSM + YSZ cathode thickness was ∼50 μm. The cells were tested at 800°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 ≥ 0) at low current densities and convex-up ( d 2 V / di 2 ≤ 0) at high current densities. The maximum power density for a cell with an anode thickness of ∼1.04 mm was ∼1.9 W/cm 2 and that for a cell with an anode thickness of ∼3.86 mm was ∼1.1 W/cm 2 . The measured short circuit current densities were -6.35 A/cm 2 for a cell with an anode thickness of ∼1.04 mm and ∼3.56 A/cm 2 for a cell with an anode thickness of ∼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°C.