Heterostructure interface effect on the ORR/OER kinetics of Ag–PrBa0.5Sr0.5Co2O5+δ for high-efficiency Li–O2 battery

Developing high-efficiency and cost-effective bifunctional electrocatalysts toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is an urgent issue for the oxygen-based electrochemical devices. Herein, an interface engineering concept has been proposed to achieve high-performance Ag–PBSC (Ag–PrBa_0.5Sr_0.5Co₂O_5+δ) heterostructure nanofibers catalyst. Benefiting from the significant ligand action and interparticle cooperation of exsolved Ag NPs and PBSC double perovskite, ORR/OER catalytic kinetics have been successfully boosted. In details, the PBSC double perovskite possessing abundant oxygen vacancies can provide oxygen channels and facilitate the transfer of electrons and oxygen. The embedded Ag NPs can deliver superior catalytic durability for the heterostructure interface. As expected, the as-synthesized Ag-PBSC heterostructure catalyst performs a favorable electrochemical performance in the oxygen-based applications. In alkaline media, the catalyst exhibits an excellent activity for ORR (E_onset: 0.88 V vs. RHE and E_1/2: 0.72 V vs. RHE) and OER (1.67 V at 10 mA cm^–2). When adopting the Ag–PBSC heterostructure catalyst in LOBs, the corresponding battery provides an outperforming capacity performance (13 000 mAh g^–1), low discharge–charge polarization (1.37 V), and considerable cycling performance (128 cycles at the restricted capacity of 3 000 mAh g^–1 and 400 mA g^–1). Apparently, the work described here confirms that the interface engineering of perovskites can open up opportunities to develop highly active and durable heterostructure electrocatalysts for multitudinous oxygen-based electrochemical applications.