Microstructure control of SOFC cathodes using the self-organizing behavior of LSM/ScSZ composite powder material prepared by spray pyrolysis

Composite particles for SOFC cathodes were synthesized by a spray pyrolysis method. The constituent materials for the cathode are provided in the form of a metal ion solution with the addition of an electrolyte sol solution, and sprayed droplets of the solution undergo pyrolysis to form composite LSM/ScSZ particles. The resultant particles have been shown to possess a structure on a nano-order with a well-controlled particle size and material composition. Also, the cathode using the composite particles has demonstrated a significant reduction in the interfacial area specific resistance by 30–50% when compared to those for conventional cathode materials. This paper describes the processes for cathode fabrication in order to understand how such a finely controlled cathode microstructure is realized. In particular, the self-organizing behavior during the course of crystal growth within the cathode is carefully observed. The present results encourage further optimization of the composite particle design in order to further improve the cathode performance.