Revolutionizing Zn-Air batteries with chainmail catalysts: Ultrathin carbon-encapsulated FeNi alloys on N-doped graphene for enhanced oxygen electrocatalysis

The sluggish kinetics of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) pose significant challenges for the viability of rechargeable Zn-air batteries. Developing efficient, cost-effective, stable, and dual-purpose oxygen electrocatalysts remains a formidable hurdle. In this study, we successfully synthesized a highly promising chainmail catalyst named FeNi@NC, comprising ultrathin carbon shells encapsulating FeNi alloy nanoparticles on N-doped graphene-like nanosheets. The strong synergistic effects between FeNi alloys and N-doped carbon shells result in outstanding bifunctional catalytic activity, particularly in alkaline media. Consequently, Zn-air batteries incorporating FeNi@NC as the catalyst demonstrate exceptional performance, operating reliably at high power density with extended lifespan. Furthermore, computational analyses provided further confirmation of the catalytic activity and revealed that the electron transfer from FeNi alloy nanoparticles to the carbon shells activates the carbon surface, leading to enhanced catalytic performance. This research not only sheds light on the rational design and synthesis of heteroatom-doped carbon materials supporting the growth-constrained transition metal alloys but also offers a practical solution for advancing the application of Zn-air batteries.