A Ternary Ni46Co40Fe14 Nanoalloy‐Based Oxygen Electrocatalyst for Highly Efficient Rechargeable Zinc–Air Batteries

Abstract Replacing noble‐metal‐based oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts is the key to developing efficient Zn–air batteries (ZABs). Here, a homogeneous ternary Ni 46 Co 40 Fe 14 nanoalloy with a size distribution of 30–60 nm dispersed in a carbon matrix (denoted as C@NCF‐900) as a highly efficient bifunctional electrocatalyst produced via supercritical reaction and subsequent heat treatment at 900 °C is reported. Among all the transition‐metal‐based electrocatalysts, the C@NCF‐900 exhibits the highest ORR performance in terms of half‐wave potential (0.93 V) in 0.1 m KOH. Moreover, C@NCF‐900 exhibits negligible activity decay after 10 000 voltage cycles with minor reduction (0.006 V). In ZABs, C@NCF‐900 outperforms the mixture of Pt/C 20 wt% and IrO 2 , cycled over 100 h under 58% depth of discharge condition. Furthermore, density functional theory (DFT) calculations and in situ X‐ray absorption spectroscopy strongly support the active sites and site‐selective reaction as a plausible ORR/OER mechanism of C@NCF‐900.