Graphene/Copper Nanoparticles as Thermal Interface Materials

Recently, graphene was extensively applied in the fields of electronic and thermal management for its extraordinary thermal conductivity (TC). The graphene prepared by venturi-assisted supercritical CO2 (scCO2) exfoliation has lots of advantages such as high quality, few defects, and extremely high in-plane TC and is usually used as thermal interface material (TIM). However, it was difficult to meet the development of three-dimensional integration due to the thermal anisotropy. Herein, we successfully introduced copper nanoparticles into graphene sheets to prepare the graphene nanocopper (Gr/Cu) composites with highly aligned graphene nanoplatelet by a vacuum filtration method. The unique structure of copper nanoparticles can significantly weaken the thermal anisotropy by providing a heat transfer channel for the graphene nanoplatelet. Experimental results revealed that through-plane thermal conductivity of Gr/Cu composites was increased by 2.05 times (5.22 W m–1 K–1) with 20 wt % copper nanoparticles doping and the thermal anisotropy decreased from 247 to 45, which means that there is great potential for TIMs.