Preparation and evaluation of mechanochemically fabricated LSM/ScSZ composite materials for SOFC cathodes

The LSM/ScSZ composite powder materials for SOFC cathodes were prepared by the mechanical method using an attrition-type particle composing machine and their electrochemical performance was examined. They are designed in such a way that relatively large LSM particles are coated with fine-grained ScSZ particles prior to the electrode fabrication process such as sintering, thus ensuring the establishment of both the ionic and electronic conducting paths within the electrode. The composite cathode using these composite powders outperformed, in the interfacial area specific resistance, a simple LSM cathode and the LSM/ScSZ composite cathode fabricated by an ordinary starting powder mixture without mechanical treatment. The interfacial area specific resistance was actually reduced by 75% relative to the simple LSM cathode, and by 50% relative to the ordinary composite cathode. In addition, the amount of ScSZ doping was reduced down to 20% by weight fraction. The present result suggests that the proposed composite particles can be considered as a potential cathode material in order to enhance SOFC cathode performance.