A hybridization cage-confinement pyrolysis strategy for ultrasmall Ni3Fe alloy coated with N-doped carbon nanotubes as bifunctional oxygen electrocatalysts for Zn–air batteries

An ultrasmall bifunctional catalyst with excellent ORR and OER properties was achieved via hybridization cage-confinement pyrolysis strategy, and shows a wide prospect for rechargeable Zn–air batteries.