Pre‐Coordination Engineering Enables Synergistic Fe‐Based Single Atoms and Atomic Clusters for High‐Performance Zinc‐Air Batteries

ABSTRACT

Integrating single atoms and atomic clusters presents a promising strategy to enhance electrocatalytic performance. Herein, a bifunctional oxygen electrocatalyst featuring Fe atomic clusters and single atoms in nitrogen‐doped carbon nanotubes (Fe _AC /Fe _SA ‐N‐CNTs) was fabricated via a pre‐coordination strategy. The low‐cost gallic acid can effectively chelate Fe ions, preventing their further aggregation into particles. Fe single‐atom sites act as the primary active centers, while adjacent Fe atomic clusters modulate their local electronic environment, thereby optimizing the adsorption energy of oxygen intermediates. Therefore, Fe _AC /Fe _SA ‐N‐CNTs exhibits outstanding bifunctional oxygen electrocatalytic activity, with a half‐wave potential ( E _1/2 ) of 0.90 V for the oxygen reduction reaction (ORR) and an overpotential ( η ₁₀ ) of 330 mV at 10 mA cm ⁻² for the oxygen evolution reaction (OER). An aqueous zinc‐air battery (A‐ZAB) assembled with Fe _AC /Fe _SA ‐N‐CNTs achieves a large peak power density of 212.3 mW cm ⁻² and remarkable cycling stability over 900 h. The quasi‐solid‐state ZAB (QSS‐ZAB) utilizing Fe _AC /Fe _SA ‐N‐CNTs delivers a high peak power density of 222.6 mW cm ⁻² , maintaining excellent cycling stability for 92 h at 0.5 mA cm ⁻² . This work demonstrates that catalysts with coexisting single atoms and atomic clusters, prepared via a pre‐coordination strategy, can not only significantly enhance catalytic performance but also achieve multifunctional catalysis.