Bead-on-string N-doped carbon nanofiber networks that spatially decouple high oxide loading from transport limitations in flexible zinc-ion batteries

Increasing active-material loading in self-supported flexible electrodes can improve energy-storage capability, but often causes slower ion transport and weaker structural integrity. Resolving this trade-off is essential for high-performance flexible batteries, yet existing high-loading electrodes often sacrifice transport efficiency or mechanical robustness. Here, we address this challenge through a rational dual-polymer electrospinning strategy that creates bead-on-string N-doped carbon nanofiber networks capable of sustaining high oxide loading while preserving efficient transport pathways and flexibility. By optimizing the vanadium-salt-to-polyacrylonitrile ratio, the resulting VO@CNF cathode achieves ∼47 wt% vanadium oxide loading together with a large surface area. The bead domains increase loading capacity and inter-fiber spacing, whereas the fibrous carbon network maintains continuous electron conduction and mechanical continuity. In addition, porous features promote electrolyte penetration and shorten ion transport pathways. This synergistic architecture delivers a specific capacity of 201 mAh g⁻ 1 at 0.4 A g⁻ 1 and retains 163 mAh g⁻ 1 at 1.0 A g⁻ 1 . When assembled into a flexible pouch cell with quasi-solid electrolyte, the device maintains stable operation with 119 mAh g⁻ 1 capacity across 0–90° bending and exhibits 73% retention after 250 cycles. These findings establish bead-on-string nanofiber as a general strategy for overcoming the trade-off between high oxide loading, ion transport, and mechanical stability in flexible energy-storage electrodes.