Thermoelectric Materials for Textile Applications

Abstract

Since prehistoric times, textiles have served an important role–providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles—making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.

A comprehensive review on the output voltage/power of wearable thermoelectric generators concerning their geometry and thermoelectric materials

“…Hybrid TE materials benefit from both the low thermal conductivity and flexibility of TE polymers and the high power factor of inorganic TE materials [160]. Moreover, the combination of organic and inorganic materials arises interfacial transport properties in the resultant hybrid TE material, resulting in the enhancement of the 𝑍𝑇 value [161]. Thus, Xu et al [162] combined PEDOT: PSS and tellurium (Te) nanowires together to take advantage from both the high flexibility and low thermal conductivity of the former and the high Seebeck coefficient of the latter.…”

Flexible Bi2Te3/PEDOT nanowire sandwich-like films towards high-performance wearable cross-plane thermoelectric generator and temperature sensor array

“…, power generator and sensor), which will lay the cornerstone of multifunctional wearable TEs. 32–39 Hence, rational design and construction of high-performance, flexible TE materials and devices are to be addressed for practical applications.…”

Copper Iodide on Spacer Fabrics as Textile Thermoelectric Device for Energy Generation

“…Furthermore, textile thermoelectrically (TE) active devices represent very cost-effective substrate materials, can be worn on the body and exhibit high flexibility, to also effectively use the heat from shaped surfaces [6][7][8][9]. For the development of textile-based components such as actuators, sensors, flexible energy storage devices or energy generation [10][11][12][13][14][15], simple coating processes such as dipping or laminating of nontoxic but effective working materials are useful for scalable applications or preparation in the textile industry. Flat flexible thermoelectric generators (TEG) with a 2-dimensional architecture could not generate an effective temperature gradient from hot to cold side.…”