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.

The development and synthesis of cathode electrocatalysts with high activity and durable stability for metal-air batteries is an important challenge in the area of electrocatalysis. Herein, we introduce a novel in-situ nitriding and phosphating strategy for producing W₃N₄ and WP from phosphotungstic acid (HPW)-polyaniline-phytic acid-Fe³⁺ organic–inorganic hybrid material. The final material has a three-dimensional porous framework with W₃N₄-WP heterostructures embedded in the carbon matrix (W₃N₄-WP@NPC). As-made materials exhibit exceptional electrocatalytic performance for the oxygen reduction reaction (ORR), with a diffusion-limiting current density of 6.9 mA·cm⁻² and a half-wave potential of 0.82 V. As a Zn-air primary cathode, the W₃N₄-WP@NPC assembled battery can provide a relatively high peak power density (194.2 mW·cm⁻²). As a Zn-air secondary air-cathode, it has great cycling stability over 500 h. This work provides a simple and efficient method for rationally designing high-performance air cathodes from copolymer-anchored polyoxometalates.

The rational design and preparation of promising cathode electrocatalysts with excellent activity and strong stability for metal-air batteries is a huge challenge. In this work, we innovate an approach of combining solvothermal with high-temperature pyrolysis utilizing zeolitic imidazolate framework (ZIF)-8 and ZIF-67 as the template to synthesize a novel hybrid material of hierarchical porous yolk–shell Co-N-C polyhedron nanocatalysts engaged in graphene nanopocket (yolk–shell Co-N-C@GNP). The obtained catalyst exhibits prominent bifunctional electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the alkaline condition, in which the half-wave potential is 0.86 V for ORR, and the over-potential for OER is 0.42 V at 10 mA·cm⁻². The rechargeable aqueous Zn-air battery fabricated with yolk–shell Co-N-C@GNP cathode deliveries an open circuit voltage (OCV) of 1.60 V, a peak power density of 236.2 mW·cm⁻², and excellent cycling stability over 94 h at 5 mA·cm⁻². The quasi-solid-state Zn-air battery (ZAB) using yolk–shell Co-N-C@GNP displays a high OCV of 1.40 V and a small voltage gap of 0.88 V in continuous cycling tests at 2 mA·cm⁻². This work provides a valuable thought to focus attention on the design of high-efficient bifunctional catalysts with hierarchical porous yolk–shell framework and high-density metal active sites for metal-air battery technologies.

Transition metal nitrides and carbides have attracted intensive attentions in metal-air battery application due to their metallic electron transport behavior and high chemical stability toward the oxygen reduction reaction (ORR). Herein, the polyoxometalate@polyaniline composite derived WN-W₂C heterostructured composite (WN-W₂C@pDC) has been fabricated through an in situ nitriding-carbonization strategy, with WN-W₂C nanoparticles implanted on N doped carbon nanorods. As-fabricated WN-W₂C@pDC demonstrates prominent electrocatalytic performance towards ORR and excellent cycling stability in metal-air battery, which possesses positive half-wave potential and large diffusion limiting current density (0.81 V and 5.8 mA·cm⁻²). Moreover, it demonstrates high peak power density of 157.4 mW·cm⁻² as Al-air primary cathode and excellent stability at the discharge–charge test (> 500 h) of Zn-air secondary battery. The excellent activity and durability of WN-W₂C@pDC catalyst should be attributed to the combined effect of intimate WN-W₂C heterointerfaces, unique embedded nanoparticles structure, and excellent electrical media of N doped carbon, confirmed by a series of contrast experiments.