Influence of the Fabric Topology on the Performance of a Textile-Based Triboelectric Nanogenerator for Self-Powered Monitoring

The fibrous surface of textiles offers a larger contact area and continuous contact with the skin, which makes them a prominent candidate for biomechanical energy harvesting using the triboelectric nanogenerator principle. Herein, a lightweight, comfortable, and robust wearable triboelectric nanogenerator (W-TENG) device is fabricated for its application in self-powered technologies. The TENG output is enhanced via a three-way process: using a textured yarn and modifying the textile material and its structural variation in fabric. The triboelectric performance is correlated to the surface morphology, roughness, and dielectric properties. The current research compares woven and knitted fabric triboelectric nanogenerators using nylon, cotton, polypropylene (PP), and polyester. The surface roughness of the different textile materials and the irregular surface morphology of woven and knitted structures are studied using a three-dimensional (3D) optical profilometer. It is observed that the convolutions on the PP and nylon yarn and the 3D configuration of knitted fabric impart higher roughness than their woven counterpart providing a larger contact area. The higher contact area between the nylon/PP pair of knitted fabric has shown 240.55, 64.96, and 460% increments in voltage, current, and power density, respectively, compared to the woven W-TENG. The knitted fabric-based TENG has additionally demonstrated improved breathability and suitability to generate electrical energy from various human motions.