N‐Decorated Main‐Group MgAl2O4 Spinel: Unlocking Exceptional Oxygen Reduction Activity for Zn‐Air Batteries

Abstract

AbstractThe development of economical and efficient oxygen reduction reaction (ORR) catalysts is crucial to accelerate the widespread application rhythm of aqueous rechargeable zinc‐air batteries (ZABs). Here, a strategy is reported that the modification of the binding energy for reaction intermediates by the axial N‐group converts the inactive spinel MgAl2O4 into the active motif of MgAl2O4‐N. It is found that the introduction of N species can effectively optimize the electronic configuration of MgAl2O4, thereby significantly reducing the adsorption strength of *OH and boosting the reaction process. This main‐group MgAl2O4‐N catalyst exhibits a high ORR activity in a broad pH range from acidic and alkaline environments. The aqueous ZABs assembled with MgAl2O4‐N shows a peak power density of 158.5 mW cm−2, the long‐term cyclability over 2000 h and the high stability in the temperature range from ‐10 to 50 °C, outperforming the commercial Pt/C in terms of activity and stability. This work not only serves as a significant candidate for the robust ORR electrocatalysts of aqueous ZABs, but also paves a new route for the effective reutilization of waste Mg alloys.