Enhanced through-plane thermal conductivity of graphene membranes by the interlayer microstructure manipulation: Multiscale numerical simulations and experimental verifications

Graphene, with ultrahigh in-plane thermal conductivity (IPTC), has been widely applied in the thermal dissipation of integrated circuits. However, the extremely low through-plane thermal conductivity (TPTC) of graphene limits its further application. In this work, a novel strategy was proposed to enhance the TPTC of graphene membranes (GNMs) by improving the interlayer bonding state through interlayer decoration with metal elements. Molecular dynamics simulations demonstrated that decoration with interlayer elements (Al, Ti, and Ni) enhanced the interfacial thermal conductance. This was attributed to interfacial chemical bonding through strong interfacial interactions (intensive electron localization) formed at the interface between metal and GN sheets as implied by the first principles calculations. Furthermore, the composite GNMs decorated with interlayer metal nanoparticles (Al, Ni, and Co) were prepared through co-reduction using thermal decomposition method. The corresponding TPTC was tested using time-domain thermoreflectance (TDTR) method which was much higher for the composite GNMs (175–400 W/m·K) than for pure GNM (∼140 W/m·K), and this was in consistent with the simulation results. Interlayer decoration, which enhanced the TPTC of GNMs, provides a novel and effective strategy for enhancing the overall thermal management performance of graphene-based materials in both vertical and horizontal directions.