An Efficient Oxygen Reduction Catalyst for Zn‐Air Battery: Cobalt Nanoparticles Encapsulated in 3D Nitrogen‐Doped Porous Carbon Networks Derived from Fish Scales

Abstract The development of a simple and eco‐friendly approach for synthesizing high‐activity and low‐cost electrocatalysts remains a huge challenge for the commercialization of zinc‐air battery technology. Herein, a facile method is demonstrated to skillfully fabricate cobalt nanoparticles encapsulated in N‐doped micro/mesoporous carbon networks (Co/N‐MC) by using natural fish scales as carbon source. The effects of pyrolysis temperature on microstructure, N‐doping and oxygen reduction reaction (ORR) electrocatalytic activity of the obtained Co/N‐MC samples are systematically investigated. The as‐synthesized Co/N‐MC catalyst exhibits better ORR catalytic activity, stability as well as superior Zn‐air battery performance compared with commercial 20 % Pt/C catalyst, owing to its three‐dimensional structures and synergistic effect of N species. The simple and eco‐friendly strategy developed for ORR catalyst in this study holds great potential for the commercial application of zinc‐air batteries.