Unlocking ultra-long stability of Zn–air batteries: synergistic role of antiperovskite carbide Fe3SnC and Fe3C nanoparticles in enhancing electrocatalytic performance

Abstract

The high efficiency, superior selectivity, and ultra-long stability of electrocatalysts are essential for high-performance, sustainable and affordable energy storage applications. Antiperovskites are functional materials with a unique tetragonal crystal structure that exhibit excellent stability and can maintain performance without change under harsh conditions, which is critical for extending battery life and slowing performance degradation. In this paper, an antiperovskite carbide, Fe₃SnC, as an auxiliary component was prepared by introducing the p-block metal Sn into an Fe-based system, and it was simultaneously anchored with Fe₃C nanoparticles onto a honeycomb meso-microporous substrate to fabricate an FeSn-NC catalyst with high activity and ultra-long stability. The catalyst showed a half-wave potential up to 0.87 V in 0.1 M KOH solution, and the current density remained at 90.8% of the initial value after 40 000 seconds of operation. DFT calculations confirmed that the synergistic interaction between Fe₃SnC and Fe₃C anchored on nitrogen-doped carbon could effectively reduce the energy barrier of the ORR rate-determining step (from *OH to OH⁻). On this basis, the Zn–air battery employing FeSn-NC as a positive electrode catalyst has an ultra-long stability of up to 2418 hours. This work developed a competitive antiperovskite carbide (Fe₃SnC) as an auxiliary component, offering insights into the rapid development of highly stable cathode catalyst materials.