Fabrication of flexible composite electrodes and their application in flexible supercapacitors for wearable electronic devices

With the rapid development of flexible wearable electronics, the demand for lightweight, safe, and durable energy storage systems has grown dramatically. Flexible supercapacitors (FSCs), featuring high power density, ultrafast charge‐discharge capability, and long cycling life, have emerged as promising candidates for next‐generation flexible devices. Nevertheless, it still remains a challenge to achieve an optimal balance between inherent mechanical flexibility and superior energy storage capability for electrodes relying on a single active material. This review first provides a comprehensive overview of recent advances in composite flexible electrodes for FSCs from the aspects of structural design, energy storage mechanisms, and key performance indicators. The fabrication strategies and active composite materials are discussed in detail, highlighting the role of material synergy and structural engineering in enhancing electrochemical performance and mechanical robustness. Applications in flexible electronic systems, including intelligent sensors, medical devices, and electronic displays, are also discussed. Finally, the opportunities and challenges faced by FSCs are presented. This review aims to provide guidance for advancing FSCs toward practical and versatile energy storage solutions by systematically summarizing recent progress and discussing the remaining challenges.