A thermoelectric wristband based on single-walled carbon nanotubes for energy harvesting

Single-walled carbon nanotubes (SWCNTs) have attracted increasing attention in wearable thermoelectric devices due to their extremely high strength and toughness. Here we introduce a flexible thermoelectric wearable wristband based on SWCNTs. High-performance SWCNTs films were successfully fabricated through ultrasonic dispersion and heat-pressing processes, exhibiting a Seebeck coefficient of 42.5 µV/K and a maximum electrical conductivity of 3503 S/cm. The flexible films exhibited excellent bending durability, ‌with‌ an impedance increase of no more than 7.6% after 400 bending cycles.The width and length of the thermoelectric legs were optimized, and a wearable thermoelectric wristband was simulated by connecting the legs in series, thereby analyzing its total output power. Furthermore, a thermoelectric wristband was fabricated by spin-coating onto a flexible printed circuit (FPC) substrate, and it achieved a maximum output power of 10.7 µW under a temperature difference of 36.5 K. This research provides an efficient and feasible energy harvesting pathway for utilizing carbon-based materials as thermoelectric materials.