A "gas-breathing" integrated air diffusion electrode design with improved oxygen utilization efficiency for high-performance Zn-air batteries.

A "gas-breathing" integrated air diffusion electrode based on BN-C catalysts was prepared with improved oxygen utilization and transfer efficiency, achieving high-performance for Zn-air batteries even without external O 2 -pumping equipment. [Display omitted] • A "gas-breathing" integrated air diffusion electrode is designed for rechargeable Zn-air batteries. • B,N-codoped carbon catalysts exhibit efficient ORR and OER bifunctional activity. • The hydrophobic diffusion layer in air diffusion electrode assists high oxygen transfer and utilization efficiency. • Air diffusion electrode endows the constructed ZABs with high-current and long-cycle battery applications. • All solid-state ZABs based on BN/C-ADE with commendable flexibility and efficient charge–discharge property. Rechargeable Zn-air batteries (ZABs) are promising candidates for next-generation sustainable energy storage due to high theoretical energy density and inherent safety. For further practical applications, in addition to developing bifunctional cathode catalysts, there is still a significant performance bottleneck of poor oxygen utilization efficiency in conventional air cathodes, which is often overlooked. To address this problem, a novel "gas-breathing" integrated air diffusion electrode based on B,N-codoped carbon (BN-C/ADE) is designed, which combines gas-diffusion layers and catalyst layers into a single architecture. The hydrophobic diffusion layer with substantial channels promotes active diffusion of oxygen from air atmosphere to reaction interface without the need for an air pump. Consequently, compared with the conventional cathode, a reduced overpotential, higher power density (118.5 mW cm−2) and long lifespan (over 170 h) are obtained for liquid ZABs based on BN-C/ADE, even without external oxygen-pumping equipment, profiting from higher oxygen utilization and transfer efficiency. [ABSTRACT FROM AUTHOR]