High-coordination Fe–N 4 SP single-atom catalysts via the multi-shell synergistic effect for the enhanced oxygen reduction reaction of rechargeable Zn–air battery cathodes

Novel Fe single-atom catalysts with highly coordinated Fe–N 4 SP structures were designed via the multi-coordination-shell synergistic effect. The optimization of the catalysts enhances their ORR activity in alkaline/acidic media towards rechargeable Zn–air batteries.