Enhancing Thermal Conductivity of Graphene Films via Secondary Graphitization under a Direct Current Arc

Thermally conductive graphene films (GFs) have been applied in the thermal management of electronic devices. Improving the thermal conductivity of GFs is critical for their applications in more systems based on high-power devices. However, traditional thermal treatment methods face great challenges in enhancing the performance of thermally conductive GFs. Herein, we applied direct current (DC) arc discharge for the secondary graphitization of GFs and investigated the enhancement in the thermal conductivity of thermally conductive GFs during the graphitization process at ultrahigh temperatures. The temperature of secondary graphitization was obtained via numerical simulations, and the effects of the atmosphere and reaction time on the thermal conductivity of thermally conductive GFs were explored to quantify the impact of these parameters on the thermal performance of GFs. The arc secondary graphitization process improved the structural order of thermally conductive GFs and reduced their defect density, thereby improving their thermal conductivity. Finally, a thermally conductive GF with a thickness of 100 ± 10 μm and a thermal conductivity of 1644 ± 11 W/mK was prepared. This GF exhibited a 9.50% improvement in thermal conductivity compared to samples without arc treatment (1501 ± 15 W/mK), exhibiting a superior performance compared with related reports. The thermal conductivity of the GF was enhanced within 2 min using the ultrahigh temperatures of >4000 K generated by arc discharge, which provides an approach for preparing high-performance thermal materials.