Thermal Conductivity of Three-Dimensionally Interconnected Graphene-Networked Cu Composite Fabricated by a Simple Two-Step Process

Abstract

A Cu composite reinforced by a three-dimensionally interconnected graphene network was synthesized in situ by a simple two-step process utilizing compacted Cu powder (99% purity) as a template for the growth of graphene. Cu composites with different graphene contents were obtained by controlling the processing parameters. The composites were approximated to have two layers of graphene with curved shapes, high aspect ratios, and which were wrapped around Cu grains at the grain boundaries. The threedimensionally interconnected graphene structure formed throughout the Cu matrix can act as a barrier to Cu diffusion and dislocation movement. Enhanced thermal conductivities (TCs) of 406 ± 5 W/mK and 385 ± 7 W/mK in the through- and in-plane directions, respectively, were obtained at room temperature for the Cu composite with a disc density of 8.16 g/cm3 and carbon content of ~ 73 ppm. The lower in-plane TC as compared to the through-plane TC could be explained by the increased number of defects as the measurement distance increased from 0.9 mm (through-plane) to 13 mm (in-plane). In conclusion, the spatial distribution of the three-dimensionally interconnected continuous graphene network throughout the Cu matrix must provide effective pathways for thermal conduction in the Cu composite, to thereby enable relatively high thermal conduction. Key words: graphene-Cu composite, 3D-interconnected graphene, Cu powder, chemical vapor deposition