Hierarchical CoP@CNTs-bridged CeO₂/CoP heterostructures-sealed hollow microcubes as highly-reversible electrocatalyst for Zn-Air batteries

A high-efficiency, reversible electrocatalyst derived from CoP nanoparticles encapsulated within carbon nanotubes that bridge CeO₂/CoP heterostructures-sealed nitrogen-doped hollow carbon microcubes (CeO₂/CoP@NC-CNT) is developed. Featuring a hierarchical structure with numerous metallic heterogeneous interfaces and efficient connection between different active phases, the developed catalyst ensures abundant active sites, superb conductivity, short electron transfer pathways, and controlled adsorption/desorption of intermediates, resulting in well-adjusted *OOH–*O conversion for rapid catalytic kinetics and high reversibility of oxygen catalytic reactions. The CeO₂/CoP@NC-CNT exhibits remarkable bifunctional activities in an alkaline electrolyte, where the oxygen evolution reaction requires a low overpotential of 260 mV at 10 mA cm⁻² and the oxygen reduction reaction demonstrates an excellent half-wave potential of + 0.85 V. A liquid-state Zn–air battery (ZAB) equipped with a CeO₂/CoP@NC-CNT air–cathode achieves a notable power density of 188 mW cm⁻² and shows exceptional galvanostatic cycling durability beyond 3500 h, significantly outperforming the commercial (Pt/C + RuO₂) counterpart. The practical potential of this innovative air–cathode catalyst is further demonstrated through the design of a solid-state rechargeable ZAB, revealing good rate performance and extended cycling life, thus offering potential for developing high-performance, cost-effective rechargeable ZABs.