Degradation Behaviours Of Fe-Doped La0.8sr0.2coo3-Delta By Thermal Stress

The improvement in durability by Fe doping to La0.8Sr0.2CoO3-delta (LSC) and its degradation mechanism were investigated in terms of structural and morphological analyses. Polarisation resistance of LSC was increased approximately by 65.7% after exposure to thermal stress at 900 degrees C for 100h because the oxygen reduction reaction was declined by particle coarsening and aggregation of LSC powders. The polarisation resistance of La0.8Sr0.2Co0.8Fe0.2O3-delta (LSCF) was increased from 0.269 to 0.328 Omega cm(2) after the heat treatment. Increasing rate of polarisation resistance of LSCF was 21.9%, which was three times lower than that of LSC due to reduced particle coarsening and aggregation by Fe doping. Particle size of LSCF powders was maintained about 0.5-3 mu m, and morphologies were also similar before and after the heat treatment. Chemical reaction between the LSCF and Sm-doped Ceria electrolyte powders did not occur despite the thermal stress, indicating the interface between the cathode and electrolyte is chemically stable.