Spray Pyrolysis Regulated FeCo Alloy Anchoring on Nitrogen–Doped Carbon Hollow Spheres Boost the Performance of Zinc–Air Batteries

Abstract

Low‐cost and high‐efficiency non‐precious metal‐based oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) bifunctional catalysts are the key to promoting the commercial application of metal–air batteries. Herein, a highly efficient catalyst of Fe0.18Co0.82 alloy anchoring on the nitrogen‐doped porous carbon hollow sphere (FexCo1‐x/N‐C) is intelligently designed by spray pyrolysis (SP). The zinc in the SP‐derived metal oxides and metal‐organic framework volatilize at high temperature to construct a hierarchical porous structure with abundant defects and fully exposes the FeCo nanoparticles which uniformly anchor on the carbon substrate. In this structure, the coexistence of Fe0.18Co0.82 alloy and binary metal active sites (Fe‐Nx/Co‐Nx) guarantees the Fe0.2Co0.8/N‐C catalyst exhibiting an excellent half‐wave potential (E1/2 ═ 0.84 V) superior to 20% Pt/C for ORR and a suppressed overpotential (280 mV) than RuO2 for OER. Assembled rechargeable Zn–air battery (RZAB) demonstrates a promising specific capacity of 807.02 mAh g−1, peak power density of 159.08 mW cm−2 and durability without electrolyte circulation (550 h). This work proposes the design concept of utilizing an oxide core to in situ consume the porous carbon shell for anchoring metal active sites and construct defects, which benefits from spray pyrolysis in achieving precise control of the alloy structure and mass preparation.

Microenvironment Tailoring of NiCo Alloys Coupled with FePc as Efficient Bifunctional Catalysts for High-Rate Zn-Air Batteries

“…Pt-based and Ru-based catalysts based on precious metals are the best catalysts for catalytic activity, but their limited resources, expensive nature, and poor corrosion resistance inevitably restrict the commercialization of Zn-air batteries. 7−9 Non-noble metal alloy materials (such as NiCo, 10−12 FeCo, 13,14 NiFe, 15,16 and CoCu 17 ) have become promising cost-effective alternative oxygen electrocatalysts due to their high electron mobility, high catalytic selectivity, and activity in OER. 18,19 Although the abundant valence-state changes are facilitated by the lattice strain differences on the two different metals in the alloy catalyst, 20,21 the regulation ability is limited and even uncontrollable due to the natural feature of the surface oxidation.…”

“…Non-noble metal alloy materials (such as NiCo, − FeCo, , NiFe, , and CoCu) have become promising cost-effective alternative oxygen electrocatalysts due to their high electron mobility, high catalytic selectivity, and activity in OER. , Although the abundant valence-state changes are facilitated by the lattice strain differences on the two different metals in the alloy catalyst, , the regulation ability is limited and even uncontrollable due to the natural feature of the surface oxidation. In addition, the catalytic activity and stability of the metal alloy electrocatalyst are greatly impacted due to the corrosive environment of acidic or alkaline electrolytes .…”