Three-Dimensional Fe-N-C-Supported Amorphous NiFe Alloy Nanoparticles As an Efficient Bifunctional Electrocatalyst for Zn-Air Batteries

The development of highly active and durable bifunctional oxygen reduction and evolution reaction (OER/ORR) electrocatalysts is vitally important for rechargeable metal-air batteries. However, little research has been done on the development of amorphous materials as bifunctional catalysts. Here, amorphous NiFe alloy nanoparticles (a-NiFe) coupled to transition metal nitrogen-doped carbon (Fe-N-C) substrate (a-NiFe@Fe-N-C) have been produced and ducted by a simple synthesis method. It is confirmed that the a-NiFe@Fe-N-C composite has significant amorphous characteristics according to XRD, HR-TEM, and SAED characterization methods, and the amorphous structure has abundant defects caused by the disordered arrangement of atoms, which is conducive to accommodate a large mass of active sites and promote the performance of catalysts. Additionally, the large specific surface area, the interconnected multistage pore structure, and the superior electrical conductivity of the Fe-N-C substrate, as well as the synergistic effect between bimetals Ni and Fe, make a-NiFe@Fe-N-C composite electrocatalyst present superior bifunctional catalytic activity and durability. Remarkably, compared with benchmark Pt/C + IrO 2 , the rechargeable liquid Zinc-air battery using a-NiFe@Fe-N-C as cathode exhibits a superior power density (170 mW·cm −2 ), specific capacity (687.65 mAh·g Zn-1 ) and cycling durability (100 h).