Spin‐State Transition in Heterometal‐Bridged Cu–MnN ₄ Motifs Overcomes Activity‐Stability Trade‐Off for Ultra‐Stable Zinc‐Air Batteries

ABSTRACT Rechargeable zinc‐air batteries (ZABs) are promising for sustainable energy storage but limited by the scarcity of efficient and durable oxygen reduction reaction (ORR) catalysts. Transition metal M–N ₄ single‐atom catalysts, particularly Mn–N ₄ , offer structural stability but face an activity‐stability trade‐off due to electronic rigidity. Herein, we overcoming this dilemma by modulating Mn spin state via incorporating an adjacent Cu atom to form a heterometallic Cu–MnN ₄ motif (CuMn/NC). Experiments and density functional theory calculations reveal that Cu induces electron reconfiguration, driving a spin transition of Mn from intermediate‐ to high‐spin states. This transition enhances electron occupancy in Mn–O antibonding orbitals, optimizes oxygen intermediate adsorption, and lowers the energy barrier of the rate‐determining step (*OH desorption) by over 30%. The CuMn/NC achieves an exceptional ORR half‐wave potential of 0.892 V vs. RHE, surpassing benchmark Pt/C (∼47 mV) and current Mn‐based catalysts (∼101 mV), while maintaining remarkable stability (>91.9% current retention after 32 h). ZABs. with CuMn/NC delivered a record peak power density (172.6 mW cm ⁻² ) and unprecedented cycling stability (>1000 h with negligible voltage decay). This study demonstrates that precise spin‐state modulation via heterometallic coordination provides a fundamental strategy for designing high‐performance, durable electrocatalysts.