Thermal conductivity and thermoelectric properties in 3D macroscopic pure carbon nanotube materials

Abstract

Sintered carbon nanotube (CNT) blocks and porous CNT sponges were prepared, and their thermoelectric properties were measured. The maximum dimensionless thermoelectric figure-of-merit, ZT, at room temperature of the sintered single-walled carbon nanotube (SWCNT) block is 9.34 × 10−5, which is twice higher than that of the sintered multi-walled carbon nanotube (MWCNT) block in this work and also higher than that of other sintered MWCNT blocks reported previously. In addition, the porous MWCNT sponge showed an ultra-low thermal conductivity of 0.021 W/(m K) and significantly enhanced ZT value of 5.72 × 10−4 at room temperature and 1 atm. This ZT value is higher than that of other 3D macroscopic pure CNT materials reported. The pronounced enhancement of the ZT in the porous MWCNT sponge is attributed to the ultra-low density, ultra-high porosity, and interconnected structure of the material, which lead to a fairly low thermal conductivity and better Seebeck coefficient. The finding of this work provides an understanding for exploring potential enhancement mechanisms and improving the thermoelectric properties of CNT-based thermoelectric composites.

Effective Conductivity of Carbon-Nanotube-Filled Systems by Interfacial Conductivity to Optimize Breast Cancer Cell Sensors

“…"φ p " was reported as 0.0005, 0.001, 0.0003, and 0.002 for the PVC/MWCNT, PET/MWCNT, epoxy/SWCNT, and PC/ABS/MWCNT samples, respectively. These levels were compared with the predictions of Equation (15). The values of (t, τ) were obtained as (1.5, 400), (3, 300), (7,145), and (8, 1600) (nm, S/m) for the PVC/MWCNT, PET/MWCNT, epoxy/SWCNT, and PC/ABS/MWCNT samples, respectively.…”

“…Carbon nanotubes (CNTs) endow significant conductivity and high mechanical properties to composites, especially polymer CNT nanocomposites (PCNT) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. A CNT aspect ratio in a range of 500–1000 creates a conductive network at extremely low concentrations of CNTs [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

Recent Development of Carbon-Nanotube-Based Solar Heat Absorption Devices and Their Application

“…Furthermore, Zhang et al [ 30 ] fabricated Bucky paper (prepared with the pressing of highly aligned CNT films) with a density of 1.39 mg/cm 3 , and the thermal conductivity reached 766 W/m·K. Yang et al [ 31 ] performed 3D microscopic analysis of SWCNTs, MWCNTs, and an MWCNT sponge. They concluded that the density of CNTs has a significant effect on thermal conductivity.…”

Modeling of thermal conductivity for disordered carbon nanotube networks

“…The unexpectedly low thermal conductivities of CNT networks were verified later by other groups. [4][5][6] For example, Yang et al [4] demonstrated that the thermal conductivity of single-walled CNT (SWCNT) networks is 0.142 W/(m•K), and can be reduced further to 0.057 W/(m•K) as the density of networks reduces from 0.217 g/cm 3 to 0.097 g/cm 3 .…”

“…This ultralow thermal conductivity of CNT networks has been attributed to both the large contact thermal resistance between CNTs and the high porosity of CNT networks. [3][4][5] When only the porosity is considered, the thermal conductivity of a CNT network k net can be written as [3,7]…”