A Zn-Doped Ba0.5Sr0.5Co0.8Fe0.2O3-delta Perovskite Cathode with Enhanced ORR Catalytic Activity for SOFCs

The insufficient oxygen reduction reaction activity of cathode materials is one of the main obstacles to decreasing the operating temperature of solid oxide fuel cells (SOFCs). Here, we report a Zn-doped perovskite oxide Ba0.5Sr0.5(Co0.8Fe0.2)(0.96)Zn0.04O3-delta (BSCFZ) as the SOFC cathode, which exhibits much higher electrocatalytical activity than Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) for the oxygen reduction reaction (ORR). The BSCFZ cathode exhibited a polarization resistance of only 0.23 and 0.03 Omega.cm(2) on a symmetrical cell at 600 and 750 degrees C, respectively. The corresponding maximum power density of 0.58 Omega.cm(-2) was obtained in the yittria-stabilized zirconia (YSZ)-based anode-supported single cell at 750 degrees C, an increase by 35% in comparison to the BSCF cathode. The enhanced performance can be attributed to a better balance of oxygen vacancies, surface electron transfer and ionic mobility as promoted by the low valence Zn2+ doping. This work proves that Zn-doping is a highly effective strategy to further enhance the ORR electrocatalytic activity of state-of-the-art Ba0.5Sr0.5Co0.8Fe0.2O3-delta cathode material for intermediate temperature SOFCs.