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

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.