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

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.