Thermoelectric and power generation properties of epoxy/SWCNT nanocomposite above and below room temperature

Scalable thermoelectric (TE) materials are of great importance for their practical applications; however, the available TE materials lack this property, in addition to their high cost, toxicity, and limited operation below room temperature (RT). In this study, highly electrically conducting single-walled carbon nanotubes (SWCNTs) were used as a networking and electrical conductivity enhancer for the epoxy matrix to form scalable and high TE performance epoxy/SWCNT nanocomposite sheet at different SWCNT loadings within the range of 2–5 wt%. Then, the TE properties, including output power, were investigated below and above RT. The Seebeck coefficient and electrical conductivity were measured in the temperature range 213–363 K. The corresponding power generation was also assessed at ΔT = 25, 45, and 65 K below and above RT conditions. The nanocomposite containing 4 wt% of SWCNT exhibits the highest electrical conductivity, recording 7.51 S m⁻¹ at 213 K and 9.18 S m⁻¹ at 363 K. The corresponding Seebeck coefficient values recorded – 66 µV K⁻¹ at 213 K and – 91 µV K⁻¹ at 363 K. The measured power output by a small leg module above RT reached 6.20, 11.18, and 18.0 nW at ΔT = 25, 45, and 65 K, respectively. Notably, measurements below RT showed nearly double the power output. This indicates that the epoxy/SWCNT nanocomposite is a promising TE material at low temperatures, making it a promising candidate for power generation in cold environments.