Advanced interfacial engineering of oxygen-enriched Fe Sn1−OSe nanostructures for efficient overall water splitting and flexible zinc-air batteries

The rational design of the highly active, durable, and cost-effective catalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) is essential for next-generation water splitting systems and zinc-air batteries. Herein, a novel strategy is demonstrated to design iron tin oxyselenide (FexSn1−xOSe) with enriched oxygen vacancies through a simple and straightforward hydrothermal and subsequent selenization process. The optimal Fe0.33Sn0.67OSe catalyst exhibits superior ORR, OER, and HER performances due to the numerous electroactive sites and high synergistic effects. The water electrolyzer requires a small voltage of 1.490 V and incredible reversibility over 24 h. Most interestingly, the Fe0.33Sn0.67OSe air-cathode based flexible ZAB exhibits a high power density of 153.96 mW cm−2 and ultralong cycle life for 400 h. This work opens a new strategy to establish highly active and durable multifunctional catalysts in next-generation energy conversion and storage systems.