A novel fabrication method for porous LSM (lanthanum strontium manganite) powders using a pore-forming agent was developed by an ultrasonic spray pyrolysis (USP) method. The spray solution was prepared for the chemical composition of LSM ((La0.85Sr0.15)0.9MnO3-δ) by dissolving proper amounts of La-, Sr- and Mn-nitrates in distilled water. To form a porousstructured LSM powder, hollow polymer particles as a pore-forming agent were mixed with a solution of nitrates. The solution of this mixture was atomized by an ultrasonic nebulizer. The atomized droplets were decomposed and synthesized in the hot zone of a furnace at 650 oC. The morphology and crystal phases of the powders were studied by SEM, TEM and XRD. Thermal analyses of the nitrate precursors and synthesized powders were performed using DSC/TG. The particle size of the prepared powders was determinate by a particle size analyzer. The structure of the porous cathode layer for a cell was fabricated by a dip-coating process using porous LSM powders. The morphology and microstructure of the coated porous cathode layer were characterized by SEM.

Keywords: Lanthanum strontium manganite, Porous powder, Cathode, Pore-forming agent, Ultrasonic spray pyrolysis method.