Yarn-based supercapacitors and sensors can be easily integrated into textiles to form flexible and lightweight self-powered wearable electronic devices, which enable stable and continuous signal detection without an external power source. However, most current supercapacitors for self-powered systems lack the stretchability to adapt to complex human body deformations, which restricts their application as a stable wearable power source. This study presents a high-performance strain-insensitive yarn supercapacitor via prestretching