Designing cost-effective and highly active oxygen reduction reaction (ORR) catalysts is critical for the development of Zn-air batteries (ZABs). Iron-nitrogen-carbon (Fe-N-C) catalysts with single-atom Fe-Nx active sites are considered as one of the most promising alternatives to noble Pt but are hindered by unsatisfactory activity and durability. Herein, a NaCl template-assisted in situ pyrolysis technique is utilized to massively fabricate Fe-N-C single-atom catalysts (SACs) anchored on the three-dimensional open-pore carbon networks (denoted as 3D SAFe). The 3D SAFe catalyst exhibits ultrahigh activity with a half-wave potential of 0.90 V (vs RHE), benefiting from the enhanced mass diffusion and the increased amount of effective Fe-N4 sites. Consequently, the ZABs assembled with 3D SAFe deliver high peak power density up to 156 mW cm-2 and outstanding durability of 80 h, suggesting the application potential of the 3D SAFe catalyst. This work inspires the rational design and synthesis of highly efficient SACs for ZABs.
Keywords: Zn−air battery; mass transfer; open-pore structure; oxygen reduction reaction; single-atom catalysts.