LAUSR

In this paper, gadolinia-doped ceria (GDC), which is a highly catalyzed oxide ionic conductor, was explored to further improve oxygen surface reaction rates using a grain-controlled layer (GCL) concept. Typically, GDC materials have been used as a cathode functional layer by coating the GDC between the electrode and electrolyte to accelerate the oxygen reduction reaction (ORR). To further improve the oxygen surface kinetics of the GDC cathodic layer, we modified the grain boundary density and crystallinity developed in the GDC layer by controlling RF power conditions during the sputtering process. This approach revealed that engineered nano-grains of GDC thin films directly affected ORR kinetics by catalyzing the oxygen surface reaction rate, significantly enhancing the fuel cell performance. Using this innovative concept, the fuel cells fabricated with a GDC GCL demonstrated a peak power density of 240 mW/cm2 at 450oC.