Carbon nanotube (CNT) yarns are promising for flexible and fabric-type wearable materials that can convert waste heat into thermoelectricity. To improve the thermoelectric properties of CNT yarns, researchers dispersed CNT filaments in a highly viscous glycerol, enabling the production of CNT yarn with highly aligned bundles together with surfactants that prevent increased thermal conductivity. This innovative approach can significantly improve carbon nanotube-based thermoelectric materials, making it possible to power wearable devices using just body heat.