Organic carbonization modification of carbon nanotubes with stable thermoelectric performance at high temperature

Abstract

Carbon nanotube-based thermoelectric composites are promising sources in the field of flexible electronics. However, they often suffer from degraded thermoelectric performance at elevated temperatures due to their low thermal stability. In this study, highly-stable carbon nanotube-based thermoelectric composite at high temperature are fabricated through organic carbonization modification. Specifically, polydopamine is used as a linker to connect carbon nanotubes with carbonized glucose, forming a protective layer on the carbon nanotube surfaces. This protective layer serves a “two birds with one stone” purpose. On one hand, the carbonized glucose coating enhances the electron transfer characteristics at the surface of the carbon nanotubes, thereby improving the efficiency of electron transfer. On the other hand, it reduces the oxidation of carbon nanotubes in air at high temperatures, resulting in improved thermoelectric stability. The composite exhibits an excellent electrical conductivity of 1014.7 ± 40.1 S cm⁻¹ and a Seebeck coefficient of 48.5 ± 1.6 μV K⁻¹, achieving a PF of 238.5 ± 11.2 μW m⁻¹ K⁻² at 513 K. At 583 K (temperature difference 310 K), the power density can reach 0.156μW cm⁻² K⁻². This approach offers a novel pathway for designing and fabricating high-performance thermoelectric materials, providing valuable insights for future applications.