Dual-Oxide-Modified Electrospun Carbon Nanofibers Enabling Hierarchically Porous Composite Electrodes for Regulated...

Zinc-based flow batteries (ZBFBs) are promising candidates for large-scale energy storage. However, their practical application is limited by uneven interfacial electric fields and uncontrolled dendrite growth during zinc deposition. Herein, we report a hierarchical zincophilic composite electrode combining a conventional carbon felt with an electrospun carbon nanofiber scaffold modified by ZnO and SiO2. This multiscale porous structure improves both electrolyte transport and charge distribution. Specifically, the macroporous carbon felt facilitates electrolyte flow, while the nanofiber network increases the electrochemically active surface area to homogenize the local electric field. Furthermore, the dual oxides act as regulated zinc nucleation sites and mechanical plasticizing components, lowering the nucleation overpotential and relieving localized stress during repeated plating and stripping. Consequently, the electrode promotes uniform and highly reversible zinc deposition under high areal loading. The resulting ZBFBs achieve highly stable performance for over 50,000 cycles at 60 mA cm-2, demonstrating exceptional durability under practical, high-current-density operations.