Recent Advances of Fiber‐Shaped Aqueous Zinc Ion Batteries: From Structure, Principles, Issues to Strategies

ABSTRACT Fiber‐shaped aqueous zinc‐ion batteries (FAZIBs) have been regarded as highly promising power supplying devices for wearable and flexible electronics because of their intrinsic safety, low cost, lightweight nature, and excellent flexibility. However, their practical development is still hindered by coupled electrochemical and mechanical issues, including Zn dendrite growth, H 2 evolution, surface passivation, cathode materials dissolution and shedding, and electrode/electrolyte interfacial separation under deformation. This review provides a critical and comprehensive overview of recent progresses in FAZIBs from composition, structural design, working principles, failure mechanisms, to mitigation strategies. First, the components of FAZIBs, including fibrous Zn anodes, fibrous cathodes, gel electrolytes, encapsulation materials, and device architectures, are systematically discussed. Then, the energy storage and flexibility‐related mechanisms are analyzed to clarify the intrinsic correlation between electrochemical behavior and mechanical adaptability. Subsequently, the major degradation pathways limiting the performance and durability of FAZIBs are summarized. Representative strategies, including rational design of flexible Zn anodes, gel‐electrolyte regulation, cathode stabilization, and interface optimization, are further highlighted. Finally, the remaining scientific challenges and future research directions are outlined. This review is expected to supply some useful guidance for the rational design of next‐generation FAZIBs with high energy density, excellent flexibility, and long‐term stability.