Wet-spinning vanadium oxide-based coaxial fibers for the construction of zinc-ion batteries

Fiber-shaped aqueous zinc-ion batteries (FAZIBs) emerge as a promising energy storage device for future wearable electronics. Vanadium-based oxides possess high theoretical capacity, benefiting from their multiple oxidation states and versatile open-framework structures, yet its practical application is largely hindered by the poor electrical conductivity and cycling instability. Herein, we develop a core–sheath fiber as a cathode for FAZIBs via coaxial wet-spinning. The incorporation of reduced graphene oxide (rGO) significantly enhances electron transport in the V2O3 core, while the utilization of holey rGO (HrGO) as a sheath guarantees rapid ion diffusion at the same time renders further mechanical and electrical supports. The obtained V2O3/rGO@HrGO fiber exhibits a high volumetric capacity of 429 mAh cm−3 at 0.4 A cm−3 and still retains 275 mAh cm−3 at 4.0 A cm−3 with improved stability. This study provides an alternative option for the design of a high performance fiber cathode for future wearable aqueous ZIBs.