Abstract: Rechargeable zinc-air batteries (ZABs) suffer from poor reversibility of Zn anode due to dendrite formation and parasitic side reactions, severely limiting their practical deployment. Here we report an interfacial engineering strategy that integrates three Bi components: metallic Bi⁰, atomic Bi-N_x sites, and Bi₂O₃ nanocrystals, anchored within a nitrogen-doped mesoporous carbon framework. This triphasic Bi interphase delivers collective synergistic effects by: (1) homogenizing Zn²⁺ nucleation, (2) accelerating Zn plating/stripping kinetics, and (3) suppressing hydrogen evolution and interfacial corrosion. Density functional theory calculations confirm that the Bi₂O₃/Bi heterointerface exhibits strong zincophilicity, markedly lowering the nucleation energy barrier and enabling uniform Zn deposition. Benefiting from these collective interfacial effects, symmetric cells with s-Bi₂O₃/Bi-NC@Zn anodes sustain dendrite-free cycling for over 520 h at 10 mA cm^-2, with negligible polarization growth. When assembled into ZABs, the engineered anodes deliver an ultrahigh power density of 829.3 mW cm^-2 and an extended lifetime of 1650 h at 5 mA cm^-2 with 80% voltage efficiency. This work establishes a triphasic Bi-based interfacial design as a powerful strategy to achieve highly reversible Zn anodes and offers a generalizable approach for advancing metal-based batteries.

Key words: Bi₂O₃/Bi heterointerface, Bi single atom, Dendrite inhibition, Surface modification, Zn anode, Zn-air battery