Self-Promoted Electrocatalysts Derived from Surface Reconstruction for Rechargeable Zinc–Air Batteries

Recent fruitful investigations on rechargeable metal–air batteries have brought about the emergence of various bifunctional catalysts toward both oxygen reduction reaction and oxygen evolution reaction. Herein, inlaid on N-doped porous carbon frameworks, FeOx–Co3O4 solid solution undergoes a reconstruction process under the discharging process of the Zn–air battery test, evolving into a heterostructure with a functionalized surface. The functionalized surface consisting of in situ formed highly conductive metallic CoFe alloy and defect-rich structure is responsible for the reinforced conductivity and reactivity. Upon surface reconstruction, the self-promoted catalyst afforded by maintained electroactive FeOx–Co3O4 and functionalized surface boosts the electrocatalytic activity and Zn–air battery performance. A near 1.2-fold enlargement in peak power density is achieved, and the charge–discharge voltage gap gradually decreases from 1.18 to 1.04 V, accompanied with a steady cycle performance for 200 h. This self-promoted electrocatalyst can provide an important inspiration for rational engineering of electrocatalytic materials.