Carbon Nanotube-Based Polymer Composite Thermoelectric Generators

Abstract

Carbon nanotube-based polymer composites possess several properties that make them ideal for use in low powered waste heat recovery applications not suitable to nonorganic crystalline materials even though their thermoelectric performance is lower, such as their light weight and flexible physical structure. Additionally, the favorable thermoelectric properties of the carbon nanotubes with moderate Seebeck coefficients and potentially large electrical conductivities result in modest power factors, while the low thermal conductivity of the polymer host aids in maintaining a temperature gradient across the composite. In order to effectively utilize a thermoelectric material in a practical application, they must be combined in a thin film device structure consisting of alternating p-type and n-type elements that are connected electrically in series and thermally in parallel. The device performance is then dictated by the intrinsic thermoelectric properties of the individual layers in the device. Ultimately, the total power output is limited by several extrinsic properties of the specific application.

Anisotropic Thermal Transport in Thermoelectric Composites of Conjugated Polyelectrolytes/Single-Walled Carbon Nanotubes

“…We found these results to be consistent in various locations, indicating relatively homogeneous mixing of CPEs and SWNTs in the micron scale. Note that these thermal conductivity data are comparable to previous reports on randomly packed polymer/SWNT composites (0.15 W m –1 K –1 ) …”

“…Because of the interaction of SWNTs with the organic matrix, polymer/SWNT composites can exhibit low thermal conductivities that are similar to what is observed for neat polymers. Polymer/SWNT composites have thus been recognized as materials that merit attention for the fabrication of flexible thermoelectric modules. , …”

Enhanced thermoelectric properties of self-assembling ZnO nanowire networks encapsulated in nonconductive polymers

“…Despite the importance of the development of flexible thermoelectric materials application in wearable devices and waste heat harvesting from curved surfaces 39 , there is a minimal number of reports on the application of ZnO for flexible thermoelectrics at near-room temperatures 22,40 , where ZnO is used in the form of powder filler for electrically conductive polymer 40 or deposited in the form of thin film on a flexible substrate 22 . Most state-ofthe-art flexible thermoelectric materials developed for low-grade heat-to-power conversion are polymer-based composites with different nanostructured fillers, such as carbon nanotubes, bismuth and antimony chalcogenides, or hybrid fillers [41][42][43][44][45] . Commonly, the matrix for the polymer-based composite is electrically conductive polymers.…”

Carboxylated CNTs‐polyvinyl fluoride based electrical film heaters with improved mechanical properties

“…In another study, the boron nitrides and CNTs blended shape memory polymer (SMP) nanocomposites were fabricated, in which shape recovery behavior was achieved through infrared light assisted heating; the SMP nanocomposite filled with 4 wt.% boron nitrides and 4 wt.% CNTs exhibited full recovery to their original shape 6 . Because of such an advantageous properties of CNTs‐polymer composites, which have been potentially used in many interesting applications including energy harvesting, 7 electromagnetic interference shielding, 8 photovoltaic power harvesting, 9 pollution control, 10 low grade heat recovery, 11 deicing, 12 electrothermal heaters, 13 and so forth, CNTs have exhibited significant Joule‐heating phenomenon when stimulated by voltage, upon infusion into polymers. For instance, polydimethylsiloxane‐multi‐wall carbon nanotube (PDMS‐MWCNT) nanocomposite films exhibit high piezo resistivity and mechanical properties 14 ; an elastomeric foam of PDMS‐MWCNTs has been reported for an excellent EMI shielding properties 15,16 .…”