▎ 摘　　要

As a next-generation thermal management material, the graphene film with outstanding thermal conductivity and superior flexibility shows attractive prospects in many applications. However, its thermal conductivity and mechanical performance are difficult to further improve because of the weak interfacial interactions between graphene sheets and a large quantity of phonon scatterings induced by structural defects. In this work, we fabricate the three-dimensional foam via forming cross-links between graphene oxide (GO) and polyimide (PI), and then, the graphitized graphene films are produced by hot-press oxidization pretreatment, hot-press carbonization, and graphitization. Further investigation demonstrates that graphitized reduced graphene oxide/polyimide (g-rGO/PI) films exhibit not only superior mechanical performance with a Young's modulus of 15.3 +/- 1 GPa and tensile strength of 142 +/- 11 MPa but also thermal and electrical conductivities of 1467 +/- 55 W m(-1) K-1 and 1.8 x 10(5) S m(-1), respectively. Therefore, these graphene-carbon composite films show great potential to be the heat spreader material applied in the field of aerospace and microelectronics owing to the optimized structure and improved properties.