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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 Ba 0.5 Sr 0.5 (Co 0.8 Fe 0.2 ) 0.96 Zn 0.04 O 3-δ (BSCFZ) as the SOFC cathode, which exhibits much higher electrocatalytical activity than Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) for the oxygen reduction reaction (ORR). The BSCFZ cathode exhibited a polarization resistance of only 0.23 and 0.03 Ω·cm 2 on a symmetrical cell at 600 and 750 • C, respectively. The corresponding maximum power density of 0.58 W·cm −2 was obtained in the yittria-stabilized zirconia (YSZ)-based anode-supported single cell at 750 • 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 Zn 2+ doping. This work proves that Zn-doping is a highly effective strategy to further enhance the ORR electrocatalytic activity of state-of-the-art Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ cathode material for intermediate temperature SOFCs.

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