Heterointerface-engineered electron-bridge in hollow carbon nanotube-anchored Fe₂P/FeCoP electrocatalyst for highly stable Zn–air batteries

Transition metal phosphides (TMPs) hold promise as effective bifunctional oxygen electrocatalysts for rechargeable Zn–air batteries (RZABs), yet their practical application is hindered by inadequate durability and sluggish kinetics. Herein, we design a heterophosphate composite comprising Fe₂P-FeCoP heterojunctions anchored on one-dimensional (1D) hollow N, P-doped carbon nanotubes (Fe₂P-FeCoP@HNPC) through controlled metal modulation of aniline-phytate nanorods. Critically, the interfacial electronic coupling between Fe₂P and FeCoP induces a cross-interfacial electron-bridge network, which drives charge redistribution to accelerate interfacial electron transfer and refines the d band adsorption energetics for optimized oxygen intermediate binding. Coupled with its hollow architecture, Fe₂P-FeCoP@HNPC enables synergistic mass/charge transfer enhancement. The synergistic electronic-structural effects endow Fe₂P-FeCoP@HNPC with exceptional bifunctional activity, achieving a high oxygen reduction reaction (ORR) half-wave potential (0.83 V vs. reversible hydrogen electrode (RHE)) and low oxygen evolution reaction (OER) overpotential (1.53 V @10 mA·cm⁻²), attributed to the stabilized electron-bridge effect and hierarchical mass/charge transfer dynamics. Fe₂P-FeCoP@HNPC assembled RZAB achieves a peak power density of 145 mW·cm⁻² and ultralong cycling stability (> 1240 h) with negligible decay. This work demonstrates a universal strategy to harmonize electronic and structural engineering in TMPs for high-performance electrochemical energy systems.