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 FeO4-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.