FeCo alloy nanoparticles embedded in N-doped carbon supported on highly defective ketjenblack as effective bifunctional electrocatalysts for rechargeable Zn–air batteries

The development of highly active non-precious metal-based electrocatalysts to accelerate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is an essential issue for practical application of metal–air batteries. Herein, hydrothermal and annealing processes are employed to prepare FeCo alloy nanoparticles in N-doped carbon shells on a defect-rich carbon support (FeCoNC/D). The introduction of defect-rich carbon support combined with the strong coupling of distributed FeCo alloy and N-doped carbon shell efficiently enhances the electrocatalytic activity. The FeCoNC/D exhibits superior bifunctional electrocatalytic activity with a half-wave potential of 892 mV (vs. RHE) for the ORR and an overpotential of 362 mV to drive a current density of 10 mA cm –2 for the OER. Moreover, Zn–air secondary battery prepared with FeCoNC/D displays a higher specific capacity of 725 mA h g Zn –1 , a power density of 157 mW cm –2 at 245 mA cm –2 , and long-term cycling stability compared to state-of-the-art Pt/C-RuO 2 . • FeCoNC supported on defective ketjenblack (FeCoNC/D) catalysts are synthesized. • Defective carbon offers high electrical conductivity and abundant active sites. • The synergy effect of FeCo alloy and N-doped carbon improves ORR and OER activity. • Rechargeable Zn-air battery with FeCoNC/D shows high power density and stability.