Helical Fiber‐Shaped Aqueous Zn‐Ion Batteries with Modified Zn Anode and Self‐Healing Gel Electrolyte for Flexible Electronics

Fiber‐shaped aqueous Zn‐ion batteries (FAZIBs) hold great promise for flexible and wearable electronics due to their inherent safety and excellent flexibility. However, their practical application is severely hindered by the simultaneous occurrence of Zn dendrite growth, hydrogen evolution, and interfacial delamination under repeated mechanical deformation. Herein, this work reports a triple synergistic strategy that addresses these challenges from materials, structural, and interfacial levels. A bismuth‐modified Zn@carbon nanotube fiber (ZnBi@CNTF) anode is designed to suppress dendrite formation and parasitic hydrogen evolution. To mitigate bending‐induced stress concentration, both the Zn anode and the cobalt hexacyanoferrate (CoHCF)@CNTF cathode are configured into a helical architecture. Furthermore, a self‐healing gel electrolyte based on dynamic borate ester crosslinked polyvinyl alcohol (PVA‐Zn(CF 3 SO 3 ) 2 ‐borax) is developed, which exhibits high ionic conductivity (6.4 mS·cm −1 ), a high Zn 2+ transference number (0.74), and rapid macroscopic self‐healing in 30 s. The fabricated FAZIB delivers a high energy density of 130.54 Wh·kg −1 and maintains about 90.2% of its initial capacity after 1000 dynamic bending cycles. This work establishes a generalized design paradigm for achieving mechanically robust and electrochemically stable fiber‐shaped batteries for wearable applications.