Altering the Symmetry of Fe‐N‐C by Axial Cl‐Mediation for High‐Performance Zinc–Air Batteries

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Fe‐N‐C catalyst is acknowledged as a promising alternative for the state‐of‐the‐art Pt/C in oxygen reduction reaction (ORR) towards cutting‐edge electrochemical energy conversion/storage applications. Herein, a "Cl‐mediation" strategy is proposed on Fe‐N‐C for modulating the catalyst's electronic structure towards achieving remarkable ORR activity. By coordinating axial‐Cl atoms to iron phthalocyanine (FePc) molecules on carbon nanotubes (CNTs) matrix, a Cl‐modulated Fe‐N‐C (FePc‐Cl‐CNTs) catalyst is synthesized. The as‐prepared FePc‐Cl‐CNTs exhibit an improved ORR activity with a half‐wave potential of 0.91 V vs. RHE in alkaline solution, significantly outperforming the parent FePc–CNTs (0.88 V vs. RHE). The advanced nature of the as‐prepared FePc‐Cl‐CNTs is evidenced by a configured high‐performance rechargeable Zn‐air battery, which operates stably for over 150 h. The experiments and density functional theory calculations unveil that axial‐Cl atoms induce the transformation of FePc from its original D4h to C4v symmetry, effectively altering the electrons distribution around the Fe‐center, by which it optimizes *OH desorption and subsequently boosts the reaction kinetics. This work paves ways for resolving the dilemma of Fe‐N‐C catalysts’ exploration via engineering Fe‐N‐C configuration.