Flexible graphite film (FGF), as a traditional interface heat dissipation material, has high anisotropy. It is a challenge to enhance both in-plane and through-plane thermal conductivity of FGF. For this reason, the effects of oxygen content, layer spacing, density and particle size on the in-plane and through-plane thermal conductivity of FGF were studied by both molecular simulation and experimental investigation. The simulation results indicate that the ways to improve the thermal conductivity of FGF include reducing oxygen content and layer spacing, increasing the density and matching the size of graphite sheets. The FGF prepared from room temperature exfoliated graphite (RTFGF) has a wide range of adjustable density (1.3–2.0 g/cm) and thickness (50–400 μm). The thermal conductivity of the RTFGF is significantly improved after heat treatment owing to reduced oxygen content and layer spacing, which is consistent with the simulation results. Moreover, RTFGF with both high in-plane (518 W⋅m⋅K) and through-plane (7.2 W⋅m⋅K) thermal conductivity can be obtained by particle size matching of graphite.

中文翻译：

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柔性石墨薄膜导热性能的分子模拟与实验研究

柔性石墨薄膜（FGF）作为传统的界面散热材料，具有较高的各向异性。提高 FGF 的面内和面内导热率是一个挑战。为此，通过分子模拟和实验研究了氧含量、层间距、密度和粒径对FGF面内和穿过面导热系数的影响。模拟结果表明，提高FGF导热系数的途径包括降低氧含量和层间距、增加石墨片的密度和匹配石墨片的尺寸。由室温膨胀石墨（RTFGF）制备的FGF具有较宽的密度（1.3-2.0 g/cm）和厚度（50-400 μm）可调范围。由于氧含量和层间距的降低，热处理后RTFGF的热导率显着提高，这与模拟结果一致。此外，通过石墨的粒径匹配，可以获得同时具有高面内（518 W⋅m⋅K）和穿面（7.2 W⋅m⋅K）导热率的RTFGF。