Effects of cell irregularity on the thermal conductivity of carbon honeycombs

J Zhang, CARBON, 131, 127-136 (2018).

DOI: 10.1016/j.carbon.2018.01.097

The recently synthesised carbon honeycombs (CHCs) are found to possess random cell shapes. However, in the previous studies the cell irregularity was omitted, because CHCs were tacitly assumed to have an idealized periodic crystal structure. With the aid of Voronoi tessellation technique and non-equilibrium molecular dynamics simulations, the influence of cell irregularity on the thermal conductivity of CHCs is investigated in this work. Our simulation results indicate that the thermal conductivity of CHCs can be greatly reduced by the irregularity of their cell shapes. Moreover, the reduction in the thermal conductivity is found to become more significant in CHCs with larger degree of cell irregularity. Our study reveals that the reduction in the thermal conductivity of random CHC structures can be attributed to the intrinsic wavy configurations of their component graphene elements, as more phonon scattering is found in CHCs with larger degree of cell wall waviness. Our study also indicates that the strain engineering is an effective avenue to overcome the reduction in the thermal conductivity induced by the cell irregularity as the thermal conductivity of CHCs can be significantly increased by external tensile strain. (c) 2018 Elsevier Ltd. All rights reserved.

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