One-Step Braided Tubular Supercapacitor for Integration with a Fibrous Strain Sensor as a Wearable Fibrous Self-Powered Integrated System

Strain sensors with wearable and self-powered characteristics have great potential in areas such as the detection of human motion and human–machine interface technology. However, most current self-powered sensors are based on two-dimensional (2D) planar structures, and the overall weight and size of such integrated devices are relatively large. Here, an integrated wearable fibrous self-powered sensing device consisting of a braided-based asymmetric tubular supercapacitor (BATSC) and a carbon nanotube/polyester@rubber braided thread (CNT/PRBT) fibrous strain sensor is presented. The BATSC braided by a one-step braiding method exhibits a high linear energy density (23.5 μWh cm–1 at a power density of 67.8 μW cm–1) and excellent electrochemical stability performance (92.2% capacitance retention after 6000 bending–recovering cycles; the initial capacitance remains almost constant at dynamic bending different angles). The fibrous self-powered strain sensing device has reliable self-powered sensing performance and can be sewn onto textiles or tied directly as a portable self-powered strain sensor for real-time detection of human joint motion (fingers, elbows, and knees), which has potential applications in wearable intelligent motion monitoring and rehabilitation training areas. The design and integration strategy of the fibrous self-powered sensing device provides insights for the development of fibrous multifunctional wearable products.