Flexible Fiber‐Shaped Supercapacitors: Structures, Materials, Fabrication Methods, and Applications

ABSTRACT The advent of wearable electronics has generated considerable interest in the development of fiber‐shaped supercapacitors (FSCs). FSCs have several applications, such as integration into wearable power fabrics for modular energy storage, coupling with specific devices, forming composite fibers, and combining with energy‐harvesting fibers to develop integrated energy‐harvesting and storage‐usage fabrics. This review provides a comprehensive overview of FSCs based on their fundamental principles, detailing various structural configurations (e.g., parallel, wrapped, twisted, and coaxial) and substrate materials (e.g., carbon‐based, polymeric, and metallic fibers), along with strategies for enhancing their electrochemical and mechanical performance. Furthermore, it outlines large‐scale fabrication techniques, such as wet spinning, synchronous coupling, direct ink writing, and thermal drawing. This review identifies the challenges currently facing FSCs research and suggests directions for future development.