High-Performance\nThermoelectric Fabric Based on a\nStitched Carbon Nanotube Fiber

Abstract

With\nthe continuous development of flexible and wearable thermoelectric\ngenerators (TEGs), high-performance materials and their integration\ninto convenient wearable devices have to be considered. Herein, we\nhave demonstrated highly aligned wet-spun carbon nanotube (CNT) fibers\nby optimizing the liquid crystalline (LC) phase via hydrochloric acid\npurification. The liquid crystalline phase facilitates better alignment\nof CNTs during fiber extrusion, resulting in the high power factor\nof 2619 μW m^–1 K^–2, which\nsurpasses those of the dry-spun CNT yarns. A flexible all-carbon TEG\nwas fabricated by stitching a single CNT fiber and doping selected\nsegments into n-type by simple injection doping. The flexible TEG\nshows the maximum output power densities of 1.9 mW g^–1 and 10.3 mW m^–2 at Δ<i>T</i> =\n30 K. Furthermore, the flexible TEG was developed into a prototype\nwatch-strap TEG, demonstrating easy wearability and direct harvesting\nof body heat into electrical energy. Combining high-performance materials\nwith scalable fabrication methods ensures the great potential for\nflexible/or wearable TEGs to be utilized as future power-conversion\ndevices.