Thermal conductivity of graphene oxide: A molecular dynamics study
J. Chen1), L. Li
Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo, 454000 Henan, Peoples republic of China
Abstract
The thermal properties of graphene oxide containing hydroxyl and epoxy functional groups were
studied using non-equilibrium molecular dynamics to understand the thermal transport phenomena
involved and the structure factors limiting heat conduction. Estimates were given in terms of phonon
mean free paths for the reduction in thermal conductivity by interior defects due to scattering. The
mechanism of phonon transport in the graphene oxide was discussed. The results indicated that the
degree of oxidation can significantly affect the thermal performance of graphene oxide. A low degree
of oxidation is necessary to enhance the phonon transport properties of graphene oxide and reduce the
probability of phonon-defect scattering. Phonon transport in graphene oxide with a high degree of
oxidation is governed by the mean free path of phonons associated with scattering from interior
defects.
Oxygen-containing functional groups can adversely affect performance and reduce the efficiency of
phonon transport in graphene oxide due to phonon mean free paths limited mainly by interior defects.
The calculated intrinsic thermal conductivity of graphene oxide at room temperature is about
72 W/m • K with an oxidation degree of 0.35 and about 670 W/m • K with an
oxidation degree of 0.05. The
phonon mean free path decreases with increasing the degree of oxidation due to enhanced
phonon-defect scattering, making the thermal conductivity very sensitive to the concentration of
oxygen-containing functional groups.