Self‐Standing Metal Organic Framework–Carbon Nanofiber Composites as Bifunctional Electrocatalysts for Rechargeable Zinc‐Air Batteries

Abstract

Abstract Metal‐organic framework (MOF)–carbon composite materials are promising candidates for use as electrocatalysts in zinc‐air batteries (ZAB). Electrospun carbon nanofibers (CNFs) are particularly advantageous as conductive substrates due to their porous and binder‐free architecture. However, achieving stable and efficient dispersion of MOFs on CNFs remains a significant challenge. In this study, we present the synthesis of a composite electrode comprising of nickel‐based metal‐organic framework decorated over cobalt oxide‐embedded carbon nanofibers (NM@CCNF), designed as a self‐standing bifunctional electrocatalyst for rechargeable ZABs. The NM@CCNF features a unique open flower petal‐like morphology providing abundant active sites for oxygen reduction (ORR) and oxygen evolution reactions (OER). Electrochemical testing demonstrated that NM@CCNF exhibited a low potential gap (Δ E ) between the ORR and OER of 0.794 V, surpassing individual noble metal catalysts and rivaling benchmark Pt/C and IrO₂ combinations. The assembled ZAB demonstrated a high specific capacity of 830 mA h g Zn −1 , and a peak power density of 77.36 mW cm −2 . Long‐term cycling stability tests over 200 cycles showed minimal voltage degradation, indicating excellent durability and rechargeability. Post‐mortem analysis confirmed the reversible formation of ZnO during operation, validating the battery's rechargeability. These findings highlight the potential of NM@CCNF as a promising candidate for next‐generation energy storage systems.