Thermal transport characteristics of supported carbon nanotube: Molecular dynamics simulation and theoretical analysis

Zhang, Yufeng; Fan, Aoran; An, Meng; Ma, Weigang; Zhang, Xing

doi:10.1016/j.ijheatmasstransfer.2020.120111

Cited by 18 publications

(5 citation statements)

References 68 publications

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“…We have observed the same behaviora central region with a clear linear temperature profile when time averaged-in all the simulations reported in this paper. It is thus very tempting [22][23][24][25][26] to apply the same temperature-gradient procedure (2) to compute the thermal conductivity as in normal diffusive systems.…”

Section: The Temperature-gradient and Temperature-difference Methodsmentioning

confidence: 99%

“…Nonequlibrium Molecular Dynamics (NEMD) simulations have been frequently used to study these nano systems 17,[21][22][23] . The common procedure of thermostatting the boundaries, waiting for a stationary profile, and then computing the thermal conductivity from Fourier's law, applied at a central region of the material, where a linear temperature profile is observed, away from the boundaries, has been applied repeatedly in the past 12,[21][22][23][24][25][26] . This method, which we refer to as the temperature-gradient method, has been a standard procedure to minimize the effect of the boundaries in the calculation.…”

Section: Introductionmentioning

confidence: 99%

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Temperature gradient and thermal conductivity in superdiffusive materials

Ren¹,

Wu²,

Cubero³

2021

Preprint

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Thermal conductivities are routinely calculated in molecular dynamics simulations by keeping the boundaries at different temperatures and measuring the slope of the temperature profile in the bulk of the material, explicitly using Fourier's law of heat conduction. Substantiated by the observation of a distinct linear profile at the center of the material, this approach has also been frequently used in superdiffusive materials, such as nanotubes or polymer chains, which do not satisfy Fourier's law at the system sizes considered. It has been recently argued that this temperature gradient procedure yields worse results when compared with a method based on the temperature difference at the boundaries-thus taking into account the regions near the boundaries where the temperature profile is not linear. We study a realistic example, nanocomposites formed by adding boron nitride nanotubes to a polymer matrix of amorphous polyethylene, to show that in superdiffusive materials, despite the appearance of a central region with a linear profile, the temperature gradient method is actually inconsistent with a conductivity that depends on the system size, and, thus, it should be only used in normal diffusive systems.

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Section: The Temperature-gradient and Temperature-difference Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temperature gradient and thermal conductivity in superdiffusive materials

Ren¹,

Wu²,

Cubero³

2021

Preprint

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“…Due to the parameterization of the elements of the entire periodic table, UFF is often recommended for systems not covered by special force fields and has been widely used in metal complexes, organic molecules, and main group compounds. − In addition, Zhang et al used the UFF force field to obtain the Li + diffusion coefficient by calculating the mean square displacement of Li + in the propylene carbonate/LLZTO solid-state electrolyte. The UFF force field has also been widely used in metallic nanofluids. − Drawing on the theoretical model of the CNT-based composite system adopted by Zhang et al and Park et al, the size of the three-dimensional periodic unit was set to 64.45 × 64.45 × 56.57 Å 3 , and periodic boundary conditions were applied in the x , y , and z directions. The number of Li 2 O 2 in the periodic unit was controlled by setting the density value of Li 2 O 2 in the Amorphous Cell module.…”

Section: Computational Detailsmentioning

confidence: 99%

Evolution of Discharge Products on Carbon Nanotube Cathodes in Li–O₂ Batteries Unraveled by Molecular Dynamics and Density Functional Theory

Liu

Pan

et al. 2022

ACS Catal.

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The performance of Li–O2 batteries (LOBs), such as capacity and overpotential, is closely related to the morphology of the discharge product. Here, the relationship between the growth behavior of Li2O2 on the surface of the carbon nanotube (CNT) cathodes and the cycle performance of LOBs was innovatively revealed based on molecular dynamics (MD) and density functional theory (DFT). Our results demonstrated that the growth of (Li2O2) n on the CNT surface mainly undergoes three stages: adhesion, branching, and connection. The stable gap between (Li2O2) n and the CNT surface was determined to be approximately 2.47 Å. Interestingly, the dense deposition thickness is positively correlated with the number of Li2O2 monomers. In addition, the formation of free Li2O2 directly induces the instability of (Li2O2) n and capacity loss. Moreover, armchair-type CNTs with larger diameters, especially single-walled CNTs and multi-walled CNTs with an odd number of tube walls were found to be more conducive to the stable growth of discharge products. Notably, (Li2O2) n is mainly composed of internal stable parts with low conductivity and amorphous components distributed on the surface with p-type semiconductor characteristics. Therefore, the regulation of the CNT structure and the preparation of catalysts to promote the conversion of Li2O2 from an ordered state to an amorphous structure play a vital role in breaking the technical bottleneck of LOBs. Our results identify the long-term controversial evolution mechanism of the product morphology, and the unique calculation ideas are also applicable to the intuitive exploration of the microscopic growth behavior of discharge products in other metal–air batteries.

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“…By performing spectral energy density (SED) analysis of the interface structure, the results show that the low-frequency acoustic branch is lifted up and the phonons are suppressed by the substrate phonon scattering [21]. In addition, the heat flow inside the SWCNT-TIM is highly directional because the SWCNT acts as a quasi-one-dimensional material, maintaining essentially the normal heat transport capacity in one direction, while the thermal transport in the opposite direction is extremely suppressed.…”

Section: Introductionmentioning

confidence: 99%

Interfacial thermal transport of carbon nanotube on substrate

Chen

Wang

2023

Preprint

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Exploring the thermal transport properties of the interface structure of low-dimensional nanomaterials contributes to a deeper understanding of the interface phonon modes and may provide theoretical support for efficient chip cooling devices. In this manuscript, we have simulated in detail the effects of system temperature, substrate location and heat flow density on the thermal transport at the SWCNT/Si interface using the Non-equilibrium Molecular Dynamics approach and predicted the interfacial thermal conductance of SWCNT/Si for second, third and fourth order phonon using the Anharmonic Inelastic model. The results show that the low-frequency acoustic branch of SWCNT is suppressed by phonon scattering from the substrate, and the low-frequency phonon branch of SWCNT is boosted by about 1 THz. The anharmonic channels and inelastic phonon scattering significantly affect the interface phonon modes at higher temperatures, and the anharmonic interactions could increase additional thermal transport channels, which result in an increased number of additional phonon peaks. The increase in temperature gradually consumes the phonons incident at the interface in SWCNT, which enhances the anharmonic scattering and weakens the nonlinear characteristics of the bimaterial heterostructure, while the weakening of the acoustic branch accompanied by the temperature increase makes the LA phonon branch thermal conduction rate slower and the interfacial thermal conductance gradually stabilizes, which leads to the weakening of the thermal rectification effect.

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Thermal transport characteristics of supported carbon nanotube: Molecular dynamics simulation and theoretical analysis

Cited by 18 publications

References 68 publications

Temperature gradient and thermal conductivity in superdiffusive materials

Temperature gradient and thermal conductivity in superdiffusive materials

Evolution of Discharge Products on Carbon Nanotube Cathodes in Li–O₂ Batteries Unraveled by Molecular Dynamics and Density Functional Theory

Interfacial thermal transport of carbon nanotube on substrate

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Thermal transport characteristics of supported carbon nanotube: Molecular dynamics simulation and theoretical analysis

Cited by 18 publications

References 68 publications

Temperature gradient and thermal conductivity in superdiffusive materials

Temperature gradient and thermal conductivity in superdiffusive materials

Evolution of Discharge Products on Carbon Nanotube Cathodes in Li–O2 Batteries Unraveled by Molecular Dynamics and Density Functional Theory

Interfacial thermal transport of carbon nanotube on substrate

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Product

Resources

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Evolution of Discharge Products on Carbon Nanotube Cathodes in Li–O₂ Batteries Unraveled by Molecular Dynamics and Density Functional Theory