Recent Advances in Fiber-Shaped Supercapacitors for Flexible and Wearable Energy-Storage Applications

The rapid advancement of flexible electronic technologies, including wearable electronics, implantable medical devices, and smart textiles, has spurred a growing interest in developing biocompatible, high-performance, and flexible energy-storage systems. Among these, fiber-shaped supercapacitors have emerged as promising candidates for next-generation flexible power sources due to their high power density, long cycle life, and excellent flexibility. In this regard, nanomaterial-based composites have been developed to further enhance their performance and practical applicability. This review systematically summarizes recent research progress in fibrous supercapacitors, with a special emphasis on design strategies and performance optimization related to established fabrication methods (such as wet spinning and coating), typical structural configurations (parallel, twisted, and coaxial designs), and key electrode materials (including metal wires, carbon-based substances, graphene, and MXene). Furthermore, this article highlights cutting-edge applications of fibrous supercapacitors in self-powered systems, wearable electronics, and biomedical devices, and discusses the prevailing challenges and future directions for their large-scale fabrication, system integration, and practical deployment.