Ultrahigh thermal and electric conductive graphite films prepared by g-C3N4 catalyzed graphitization of polyimide films

High-efficiency heat-dissipation materials are in urgent need in microelectronics industry in 5G era. However, large-scale, low-cost, and high-efficiency preparation technologies still have great challenges. Here, ultrahigh thermal and electric conductive graphite films prepared by graphite-phase carbon nitride (g-C3N4) catalyzed graphitization of polyimide film (PI) were reported for the first time. The graphite film obtained from 0.25 wt% g-C3N4 catalyzed polyimide graphitization (G0.25) has homogeneous and perfect graphene structure and state-of-the-art properties. The d-spacing of the graphite layers is about 0.335 nm, which is similar to the ideal layer thickness of graphene (0.334 nm). The thermal conductivity is 1781 W·m−1·K−1 and the conductivity is 1.63 × 106 S·m−1, which is 1.49 and 2.18 times of graphite film from pure PI film, 1.94 and 2.34 times of graphite film from commercialized Kapton film (I-film), respectively. The thermal conductivity of G0.25 film is 4.52 times of Cu and 7.46 times of Al. More importantly, the addition of g-C3N4 can reduce the graphitization temperature from 2800 to 2500 ℃, which can reduce the energy consumption by 20.5% in the whole polyimide graphitization process. The developed preparation technology has important guiding significance and very attractive industrial application value for the preparation of large-scale, low cost and high-quality heat dissipation materials.