Manipulating Hierarchical Orientation of Wet‐Spun Hybrid Fibers via Rheological Engineering for Zn‐Ion Fiber Batteries

Abstract Wet‐spinning is a promising strategy to fabricate fiber electrodes for real commercial fiber battery applications, according to its great compatibility with large‐scale fiber production. However, engineering the rheological properties of the electrochemical active materials to accommodate the viscoelasticity or liquid crystalline requirements for continuous wet‐spinning remains a daunting challenge. Here, with entropy‐driven volume‐exclusion effects, the rheological behavior of vanadium pentoxide (V 2 O 5 ) nanowire dispersions is regulated through introducing 2D graphene oxide (GO) flakes in an optimal ratio. By optimizing the viscoelasticity and liquid‐crystalline behavior of the spinning dope, the wet‐spun hybrid fibers display controlled hierarchical orientation. The wet‐spun V 2 O 5 /rGO hybrid fiber with the optimal 10:1 mass fraction (V 2 O 5 /rGO 10:1 ) exhibits a highly oriented nanoblock arrangement, enabling efficient Zn‐ion migration and an excellent Zn‐ion storage capacity of 486.03 mAh g −1 at 0.1 A g −1 . A half‐meter long quasi‐solid‐state fiber Zn‐ion battery is assembled with a polyacrylamide gel electrolyte and biocompatible Ecoflex encapsulation. The thus‐derived fiber Zn‐ion battery is integrated into a wearable self‐powered system, incorporating a highly efficient GaAs solar cell, which delivers a record‐high overall efficiency (9.80%) for flexible solar charging systems.