Improved electrochemical activity of Bi0.5Sr0.5FeO3-δ-Ce0.9Gd0.1O1.95composite cathode electrocatalyst for solid oxide fuel cells

Developing MIEC materials with high electrocatalytic performance for the ORR and good thermal/chemical/ structural stability is of paramount importance to the success of solid oxide fuel cells (SOFCs). In this work, high -activity Bi0.5Sr0.5FeO3-delta-xCe(0.9)Gd(0.1)O(1.95) (BSFO-xGDC, x = 10, 20, 30 and 40 wt%) oxygen electrodes are synthesized, and confirmed by XRD, SEM and EIS, respectively. The crystal structure, microstructure, electrochemical property and performance stability of the promising BSFO-xGDC composite cathodes are systematically evaluated. It is found that introducing GDC nanoparticles can obviously improve the electrochemical property of the porous composite electrode. Among all these composite cathodes, BSFO-30GDC composite cathode shows the best ORR activity. The peak power density of anode supported single cells employing BSFO-30GDC composite cathode reaches 709 mW cm(-2) and the electrode polarization resistance (R-p) of the BSFO-30GDC is about 0.14 Omega cm(2) at 700 degrees C. The analysis of the oxygen reduction kinetic indicates that the major electrochemical process of the GDC-decorated composite cathode is oxygen adsorption-dissociation. These preliminary results demonstrated that BSFO-30GDC is a prospective composite cathode catalyst for SOFCs because of its outstanding ORR activity.