Zinc-based fiber-shaped rechargeable batteries: Insights into structures, electrodes, and electrolytes

The rapid evolution of flexible wearable electronics has spurred a growing demand for energy storage devices, characterized by low-cost manufacturing processes, high safety standards, exceptional electrochemical performance and robust mechanical properties. Among novel flexible devices, fiber-shaped batteries (FSBs) have emerged as prominent solutions exceptionally suited to future applications, owing to their unique one-dimensional (1D) architecture, remarkable flexibility, potential for miniaturization, adaptability to deformation and compatibility with the conventional textile industry. In the forefront research on fiber-shaped batteries, zinc-based FSBs (ZFSBs) have garnered significant attentions, featured by the promising electrochemical properties of metallic Zn. This enthusiasm is driven by the impressive capacity of Zn (820 mAh·g⁻¹) and its low redox potential (Zn/Zn²⁺: −0.76 V vs. standard hydrogen electrode). This review aims to consolidate recent achievements in the structural design, fabrication processes and electrode materials of flexible ZFSBs. Notably, we highlight three representative structural configurations: parallel type, twisted type and coaxial type. We also place special emphasis on electrode modifications and electrolyte selection. Furthermore, we delve into the promising development opportunities and anticipate future challenges associated with ZFSBs, emphasizing their potential roles in powering the next generation of wearable electronics.