Bimetallic phosphides-oxides heterostructures coupled heteroatom-doped carbon as bifunctional electrocatalysts for Zn-air batteries

Designing efficient bifunctional catalysts with multi-component composites is essential for the application of zinc-air batteries (ZABs). Herein, a bimetallic phosphides-oxides heterostructures coupled heteroatom-doped carbon (FeCoP-FeCo₂O₄@PNPC) was designed by in-situ growth of phosphor-oxide heterostructures on heteroatom-doped carbon materials and employed as bifunctional electrocatalyst for ZABs. The heteroatom-doped carbon substrate with ORR active sites can effectively improve the conductivity and the double transition metal atoms can enhance the catalytic activity. The heterostructure adjusts the d-band center, making the material gain and loss of electrons are at a medium level, which is conducive to the material’s capture of raw materials and the release of products. is beneficial to electron transfer. The dense FeCo₂O₄ nanorods act as a protection layer to improve stability, and the oxide-phosphide heterostructure and synergistic coupling with the heteroatom-doped carbon substrate also contribute to the catalytic activity. The small ΔE of 0.765 V for catalyzing both OER and ORR, high power density of 121.6 mW·cm^–2 and the extraordinary long-term stability of more than 240 h for liquid state rechargeable ZAB can be realized. The flexible solid-state rechargeable ZAB with FeCoP-FeCo₂O₄@PNPC also exhibits superior mechanical flexibility and cycling stability.