Effects of pressurization on cell performance of a microtubular SOFC with Sc-doped zirconia electrolyte

In this study, we fabricated an anode-supported microtubular solid oxide fuel cell (SOFC) with the cell configuration La0.6Sr0.4Co0.2Fe0.8O3 (LSCF)-Ce0.8Gd0.2O1.9 (CGO) cathode/CGO buffer layer/(ZrO2)(0.89)(Sc2O3)(0.1)(CeO2)(0.01) (ScSZ) electrolyte/Ni-ScSZ anode. A power generation test of the SOFC was carried out at 0.1-0.7 MPa at 650 degrees C. By using a wet H-2-N-2 gas mixture and air, the maximum power density of the microtubular cell was found to be 0.68 W cm(-2) (at 2.6 A cm(-2), U-f=78%) at atmospheric pressure (0.1 MPa). With increasing the operating pressure, the performance of the cell was improved, and the power density reached 1.48 W cm(-2) (at 2.8 A cm(-2), U-f=86%). It was confirmed by the current interruption method that both polarization and ohmic resistances decrease under a pressurized condition. (C) 2008 The Electrochemical Society.