• • FeN5@N-C hollow microplates achieve a half-wave potential of 0.93 V vs. RHE, surpassing Pt/C (typically 0.85–0.90 V) and enabling a 225.3 mW cm−2 peak power density in Zn-air batteries, directly addressing the performance bottleneck of non-precious ORR catalysts.
• • The axial nitrogen coordination (Fe-N5) induces additional 3d-2p orbital hybridization that weakens OH* binding compared to planar Fe-N4, as confirmed by theoretical calculations, providing a mechanistic basis for enhanced intrinsic activity.
• • The polydopamine-assisted hollowing strategy is versatile, successfully encapsulating Ni, Co, Mn, and Cu single atoms into N-doped carbon hollow microplates, demonstrating a platform for synthesizing diverse single-atom catalysts with tailored coordination environments.
• • Zn-air batteries using FeN5@N-C air-cathode exhibit stable cyclability up to 400 h, indicating excellent durability under operational conditions, a critical requirement for practical energy storage applications.