High-Performance Platinum-Perovskite Composite Bifunctional Oxygen Electrocatalyst for Rechargeable Zn–Air Battery

摘要

Constructing highly active electrocatalysts with superior stability at low cost is a must, and vital for the large-scale application of rechargeable Zn-air batteries. Herein, a series of bifunctional composites with excellent electrochemical activity and durability based on platinum with the perovskite Sr(Co0.8Fe0.2)(0.95)P0.05O3-delta (SCFP) are synthesized via a facile but effective strategy. The optimal sample Pt-SCFP/C-12 exhibits outstanding bifunctional activity for the oxygen reduction reaction and oxygen evolution reaction with a potential difference of 0.73 V. Remarkably, the Zn-air battery based on this catalyst shows an initial discharge and charge potential of 1.25 and 2.02 V at 5 mA cm(-2), accompanied by an excellent cycling stability. X-ray photoelectron spectroscopy, X-ray absorption near-edge structure, and extended X-ray absorption fine structure experiments demonstrate that the superior performance is due to the strong electronic interaction between Pt and SCFP that arises as a result of the rapid electron transfer via the Pt-O-Co bonds as well as the higher concentration of surface oxygen vacancies. Meanwhile, the spillover effect between Pt and SCFP also can increase more active sites via lowering energy barrier and change the rate-determining step on the catalysts surface. Undoubtedly, this work provides an efficient approach for developing low-cost and highly active catalysts for wider application of electrochemical energy devices.