Low-Polarization Composite Cathodes Based on Nanocatalysts and Oxygen Ion Conductor for Solid Oxide Fuel Cell (SOFC) Applications
An ideal cathode may be made of highly conducting ionic and electronic conductor with desired nanostructure. Thus, the objective of this work is to develop high performance composite cathode consisting of an oxygen ion conductor and metallic and/or nonmetallic catalysts with nanostrcutrures. A one-step synthesis method is developed to form colloidal Ag nanocatalysts by reducing silver ions with sodium borohydride (NaBH4) using adequate capping and stabilizing agents. As a result, a composite cathode made of Bi2O3-based ionic conductor and well-dispersed Ag nanocatalysts is obtained at the temperature as high as 600 °C. The commonly used composite cathode, LSM-YSZ, is also investigated for comparison. The crystal structure, microstructure, and electrical/electrochemical properties of the developed composite cathode are investigated using XRD, FESEM, TEM, and impedance spectroscopy.