Carbon Nanotube Yarns Tailored Using Dispersants and Surfactants for Flexible and Wearable Thermoelectric Generators
Nguyen Ngoc Anh, Naofumi Okamoto, Ryo Abe, Aghnia Dinan Maulani Heriyanto, Nikita Kumari, Gilbert Pado, S. Tanimura, Yongyoon Cho, Manish Pandey, Hiroaki Benten, Masakazu Nakamura
Abstract
High Resolution Image Download MS PowerPoint Slide Carbon nanotube (CNT) yarns have emerged as a promising candidate for flexible and fabric-type wearable thermoelectric devices. This study developed CNT yarns tailored by a low-cost, fast, and environmentally friendly CNT dispersion method using glycerol as a dispersant and polyoxyethylene(50) stearyl ether as a surfactant. A high power factor of 242 μW m –1 K –2 was obtained, which is ca. three times higher than that of the previous dispersion method. The significant contribution is the 2-fold increase of electrical conductivity (from 325 to 747 S cm –1 ), which originates from the higher degree of disentanglement in dispersion and better CNT alignment in the yarn. Another contribution is the suppression of the increase in thermal conductivity as a possible side effect of the CNT alignment, which is concluded to be due to the surfactant adsorbed on CNT bundles. As a result, the figure of merit ZT value was successfully improved by ca. a factor of 3.