Enhancing the bifunctional activity of CoSe2 nanocubes by surface decoration of CeO2 for advanced zinc-air batteries

The coupling of oxygen evolution and reduction reactions (OER and ORR) plays a key role in rechargeable Zn-air batteries (ZABs). However, both OER and ORR still suffer from sluggish kinetics, even when using the mainstream precious metal-based catalysts. Herein, oxygen vacancies-rich CeO2 decorated CoSe2 nanocubes are proposed as a novel air electrode to drive OER and ORR for ZABs. The resultant CeO2 coupled CoSe2 nanocubes (CeO2@CoSe2-NCs) catalyst exhibits a significantly enhanced bifunctional activity relative to the pristine CoSe2-NCs and the pristine CeO2. Moreover, an assembled ZABs using this CeO2@CoSe2-NCs electrode delivers a high output power density of 153 mW cm−2 and a long-life stability over 400 cycles, superior to the benchmark Pt/C-IrO2 electrode. Theoretical calculations reveal that the electronic interaction and oxygen vacancies in CeO2@CoSe2-NCs contribute to efficient oxygen electrocatalysis. This protocol provides a promising approach of constructing oxygen vacancies in hybrid catalysts for energy conversion and storage devices.