Restricting Growth of Ni₃Fe Nanoparticles on Heteroatom-Doped Carbon Nanotube/Graphene Nanosheets as Air-Electrode Electrocatalyst for Zn–Air Battery

Exploring bifunctional oxygen electrode catalysts with efficient and stable oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) performance is one of the limitations for high-performance zinc–air battery. In this work, Ni3Fe alloy nanoparticles incorporated in three-dimensional (3D) carbon nanotube (CNT)/graphene nanosheet composites with N and S codoping (Ni3Fe/N–S–CNTs) as bifunctional oxygen electrode electrocatalysts for zinc–air battery. The main particle size of Ni3Fe nanoparticles could be well restricted because of the unique 3D structure of carbon nanotube/graphene nanosheet composites (N–S–CNTs). The large specific area of N–S–CNTs is conducive to the uniform dispersion of Ni3Fe nanoparticles. On the basis of the synergistic effect of Ni3Fe nanoparticles with N–S–CNTs, and the sufficient exposure of reactive sites, the synthesized Ni3Fe/N–S–CNTs catalyst exhibits excellent OER performance with a low overpotential of 215 mV at 10 mA cm–2, and efficient ORR activity with a half-wave potential of 0.877 V. When used as an electrocatalyst in zinc–air battery, the device exhibits a power density of 180.0 mW cm–2 and long term durability for 500 h.