FeNx/ZnSe/Fe Heterojunctions Embedded in Leafy N-Doped Carbon as Efficient Bifunctional Oxygen Electrocatalysts for Flexible Rechargeable Zn–Air Batteries

Flexible quasi-solid zinc–air batteries, known for their efficiency and promising potential as an energy storage system, have found extensive applications in the fields of portable power supply, wildlife rescue, and flexible wearable devices. Herein, a FeNx/ZnSe/Fe heterojunction nanocomposite anchored on leafy nitrogen-doped carbon (FeNx/ZnSe/Fe–NC) is developed as a highly active bifunctional catalyst via one-step high-temperature selenization of Fe-doped zeolitic imidazolate frameworks 8. The formation of the heterostructure FeNx/ZnSe/Fe is conducive to accelerating electron transfer and improving the activity of the oxygen reduction reaction and oxygen evolution reaction. Moreover, FeNx/ZnSe/Fe–NC exhibits exceptional performance in liquid Zn–air batteries, comparable to the potency of industrially produced catalysts fabricated from precious metals. Notably, the gel polymer electrolyte (GPE) with a double-network structure, composed of poly(vinyl alcohol)- and polyacrylamide-modified with dimethyl sulfoxide (PVA–PAM–DMSO), exhibits significantly higher conductivity (193.5 mS cm–1) and excellent water retention (93.6%). As a result of the FeNx/ZnSe/Fe–NC catalyst and PVA–PAM–DMSO GPE, a flexible Zn–air battery with high-rate capability has been achieved, which demonstrates a high open-circuit potential of 1.51 V. This battery displays exceptional performance with excellent durability, adaptability, and adjustment capacity across a broad temperature range.