Superior thermal conductivity of layered RGO/Cu composites by multi-step electrodeposition

We developed a layered composite with directional distributed reduced graphene oxide (RGO) in a copper matrix through a double-slot multi-step electrodeposition method, playing to the advantage of in-plane thermal conductivity of RGO. The resulting RGO/Cu composite has superior thermal conductivity up to 545 W m −1 K −1 (150% of copper), which was determined by the growth behavior of the RGO flake on the copper substrate through adjusting electrodeposition time. By analyzing the structure, distribution status and its relationship with thermal conductivity, three factors including of structural integrity of RGO, thermal conduction network and interfacial effect between RGO layers were proposed. With the increase of deposition time, the restoration of RGO lattice structure and the formation of a complete thermal conduction network both promoted the phonon transmission, which was beneficial to the improvement of thermal conductivity. The multi-layer stacking of RGO, however, could generate the interlayer interfacial effects, resulting in the phonon scattering and unfavorable to the thermal conductivity. Therefore, proper adjustment of RGO deposition time resulted in excellent thermal conductivity of RGO/Cu composite, meeting the demands for the heat dissipation performance of the instrument. • Reduced graphene oxide (RGO) was directional in Cu matrix by multi-step deposition. • RGO/Cu composite has superior thermal conductivity up to 545 W m −1 K −1 (150% of Cu). • Structural integrity, thermal conduction network and interface effect were proposed. • The deposition time of RGO was adjusted to achieve excellent thermal conductivity.