Influences of starting particulate materials on microstructural evolution and electrochemical activity of LSM-YSZ composite cathode for SOFC

LSM-YSZ composite electrodes are prepared from a mixture of YSZ and LSM particles. Commercial YSZ particles were mixed with polymerizable complex method-driven LSM powders of two different particle sizes, 81 and 210 nm. The correlations between sintering temperature, microstructure and performance of composite cathode have been studied. It was found that optimum sintering temperature differs depending upon the LSM particle size. The composite cathode derived from finer LSM particles displayed lowest polarization resistance similar to 0.46 Omega cm(2) when sintered at 1100 degrees C, whereas the same resistance was observed for the electrode involving larger LSM sintered at 1200 degrees C. The microstructural changes evolved during the course of sintering and the resulting electrodes were investigated by scanning electron microscopy and impedance spectroscopy.