Seamlessly knitted stretchable comfortable textile triboelectric nanogenerators for E-textile power sources

Textile-based triboelectric nanogenerator (t-TENG) is one of the most promising technologies for wearable power sources of smart electronic textiles. It is still a challenge to integrate t-TENGs into apparel without compromising aesthetic and comfort of textiles. In this work, a stretchable and comfortable t-TENG is developed by using advanced knitting technology for harvesting human motion energies, and it can be integrated into knitwear seamlessly and conveniently. Ag conductive yarns are wrapped with polytetrafluoroethylene (PTFE) and nylon66 (PA66) respectively for knitting the t-TENG. The t-TENG is fabricated by directly knitting the two yarns into a tubular structure, of which the two yarns are kept apart at the initial or relaxed state and kept in contact at stretched or compressed state. At stretching motion mode, a peak power density reaches 1484 mu W/m(2); at compression motion mode, it reaches 7531 mu W/m(2). The t-TENG is demonstrated to be comfortable, breathable and soft. Furthermore, a pair of knitted pants is prepared by using intarsia technique to integrate this t-TENG seamlessly to harvest knee-bending energy. This study suggests the potential of t-TENGs for comfortable smart garment with advanced knitting technology.