Enhancing the oxygen reduction reaction activity and durability of a double-perovskite via an A-site tuning

摘要

The major factors limiting the electrochemical performance of a perovskite cathode for ceramic-based fuel cells are the sluggish oxygen reduction reaction (ORR) kinetics and poor durability, which are largely determined by the Asite elements. In this work, to enhance the ORR activity and stability, we present an effective strategy of tuning the A-site dopant in a layered double perovskite oxide of Ba0.8Gd0.8Pr0.4Co2O6-delta (BGPC). When applied as a cathode on a La0.8Sr0.2Ga0.8Mg0.2O3-delta (LSGM) electrolyte-supported cell, it demonstrates high electrochemical performance, achieving an area-specific resistance (ASR) of 0.170 Omega cm(2), and a peak power density (PPD) of 1.189 W cm(-2) at 800 degrees C, better than those acquired from a state-of-the-art (La0.6Sr0.4)(0.95)Co0.2Fe0.8O3-delta(LS95CF)-based cathode. The single cells with the BGPC cathode exhibit better performance and stability (a degradation rate of 0.074% h(-1)) than the cells with the LS95CF cathode (a PPD of 1.079 W cm(-2) at 800 degrees C and a degradation rate of 0.13% h(-1)) under the same operating conditions. By the electrochemical performance evaluation and characterizations, it is suggested that A-site tuning on a double-perovskite oxide can be a promising strategy to enhance the electrode activity and durability of fuel cells.

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