Efficient Bifunctional Oxygen Electrocatalysts for Rechargeable Zinc–Air Battery: Fe3O4/N−C Nanoflowers Derived from Aromatic Polyamide

Graphical Rechargeable batteries : N-doped carbon nanoflower with embedded Fe 3 O 4 −Vo nanoparticles was successfully prepared by a facile and scalable method. This material which showed excellent ORR/OER activity and performance in zinc-air battery. Experiment and density functional theory results demonstrate that the high catalytic activity is primarily due to the surface oxygen vacancy of Fe 3 O 4 nanoparticles. The development of low-cost, high-activity bifunctional oxygen electrocatalysts for rechargeable zinc–air batteries is highly desired. Herein, N-doped carbon nanoflower embedded Fe 3 O 4 nanoparticles were prepared using a simple and scalable method. The obtained electrocatalyst exhibits excellent activity and stability toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), as well as a small potential gap of 0.72 V between the half-wave potential of ORR and the onset potential of OER potential, which is superior to the most previously reported bifunctional ORR/OER catalysts. The corresponding zinc–air battery exhibits good charged/discharge cycle performance as well as excellent discharge property, with a power density of 136.8 mW cm −2 at 200 mA cm −2 outperforming commercial Pt/C (96.5mW cm −2 ). Experiment results and density functional theory demonstrate that the high catalysis activity is mainly caused by the surface oxygen vacancy of Fe 3 O 4 nanoparticles. This study sheds new light on the ORR/OER bifunctional electrocatalyst design.