Coupling of Indium Clusters with Atomic Fe-N4 on Carbon for Long-term Rechargeable Zn-Air Batteries

Abstract

The single atom electrocatalysts with the typical metal-nitrogen-carbon sites possess good oxygen reduction reaction (ORR) activity, yet challenges remain in fabricating rechargeable Zn-air batteries (ZABs) due to their poor oxygen evolution reaction (OER) performance. Herein, we demonstrated the in-situ anchoring of indium clusters on carbon matrix with iron-nitrogen-carbon sites via the pyrolysis of supermolecule aggregation coordinated with indium and iron ions, aimed to prepare advanced bifunctional electrocatalysts for ORR and OER. With the detailed atomic structure analysis, the modulation on coordination environment between indium cluster and iron-nitrogen-carbon sites induces asymmetrical charge distribution to reduce the reaction barrier via the the p-d orbital hybridization, thus achieving superior bifunctional electrocatalytic activity. Consequently, the rechargeable ZABs demonstrated a cycling durability of 1650 h. Moreover, the solid-state batteries also exhibited a large power density of 220.0 mWcm^-2. The work provides a feasible guide for rational incorporation of metal clusters with single atom sites to enhance bifunctional electrocatalysis.