PEDOT/CNT/Bi₂Te₃ coated porous thermoelectric yarns for textile based wearable thermoelectric generator

Fiber- and yarn-based thermoelectric materials play an essential role in the design of fabric-based flexible thermoelectric generators (FTEGs) which may overcome the wearable difficulties of existing film-based FTEGs. In this study, we used a robust coating method to produce high-performance thermoelectric yarns for wearable applications. An organic/inorganic hybrid coating agent composed of PEDOT:PSS, MWCNT, and Bi₂Te₃ was used to coat an alkali modified porous polyester yarn. The organic/inorganic hybrid material contributes to the improved thermoelectric properties. The porous modification of polyester yarns improves the wicking property of the fibers and enhances the adhesion stability between yarn substrate and the coating layer. A compromised optimal power factor of 12.3 μWm⁻¹ K⁻² could be achieved by 20 wt% Bi₂Te₃ loading. The corresponding electrical conductivity and Seebeck coefficient were 5526.8 S m⁻¹ and 47.1 μV K⁻¹ at room temperature respectively. A fabric thermoelectric generator with five yarn legs could generate an open circuit voltage of 2.95 mV at a temperature difference of 30 °C, demonstrating its potential application in wearable applications.