Y. Du, J. Zhou, P. Ying, J. Zhang, Effects of cell defects on the mechanical and thermal properties of carbon honeycombs. Computational Materials Science 187, 110125 (2021).
Published in Computational Materials Science, 2020
Cell defects are inevitable during the fabrication of carbon honeycombs (CHCs), which, however, were tacitly ignored in previous studies. In this work, the effects of defects including Stone-Wales (SW) defect and single-wall vacancy (SV) defect on the mechanical and thermal properties of CHCs are investigated by using molecular dynamics simulations. Our results show that the Young’s modulus of CHCs has nearly a constant value around 16.5 GPa, which is almost independent with the defect concentration. However, the tensile strength and fracture strain are reduced by about 40% and 20%, respectively, when the CHCs have a defect concentration of 2%. Additionally, the influence of SV defect on the fracture properties of CHCs is generally larger than that of its SW counterpart. The influence of cell defects on the mechanical properties of CHCs is well explained by the theories of damage and fracture mechanics. Our simulation results also show a reduction in the thermal conductivity of CHCs containing SW and SV defects. This reduction can be up to 23% when the defect concentration of CHCs is 2%. The reduced thermal conductivity observed in defective CHCs can be attributed to the wavy configuration of the component graphene nanoribbons in defective cells, which can increase the phonon scattering of CHCs. In addition, the reduced heat capacity of CHCs with SV defects can be another important factor inducing the reduction in their thermal conductivity.