Stable oxygen reduction catalysts for enhancing rechargeability for zinc–air batteries: FeCoCu nanoparticles embedded in N-doped carbon matrices

Abstract

Zinc–air batteries are potential devices for energy conversion and storage, offering high energy and power density. Efficient, durable, and cost-effective electrocatalysts that accelerate sluggish oxygen reduction kinetics are crucial for achieving high performance. Here we have developed a high-performance oxygen reduction catalyst based on N-doped carbon and FeCoCu particles encapsulated in graphitic carbon nanotube composites (N-doped carbon/FeCoCu). Through the systematic experimental and simulation studies, we propose a synergetic coupling among FeCoCu nanoparticles and N-doped carbon nanotubes. The electron transfer from FeCoCu nanoparticles to carbon active sites through metal–N–C moieties affects the crystal structure, local environment, and electronic properties of the catalyst, enhancing its conductivity, electrocatalytic performance, and reaction kinetics, while also providing exceptional durability in alkaline electrolyte. Consequently, as an alternative to the precious Pt catalyst, N-doped carbon/FeCoCu catalyst used in the air cathode of zinc–air batteries exhibits remarkable specific capacities (810 mA h g⁻¹) with large energy densities (918 W h kg⁻¹), and a peak power density of 154.7 mW cm⁻². Additionally, impressive reversibility and stability are demonstrated throughout extensive charge/discharge cycles over 900 h, holding great potential for practical applications in next-generation sustainable and green rechargeable batteries.