High-efficiency thermal management materials have attracted increasingly more attention in the heat dissipation of electronic chips, LED light and electro-thermal heating. Herein, we judiciously designed and synthesized thermally conductive nanocomposite films with tunable electrical conductivity, by assembly of graphene oxide (GO) and hexagonal boron nitride (h-BN) nanosheets. Specfically, the GO/BN/cellulose nanocrystal (CNC) hybrid dispersions, which were prepared by mixing and stirring GO and BN/CNC dispersions, were converted into macroscopic films through the evaporation-induced self-assembly. Cellulose nanocrystals (CNC) played a key role in the assembly process, becuase they acted as a dispersant for h-BN nanosheets and formed chiral-structured connection between h-BN and GO. The thermal and electrical performance was tuned by different ratios of reduced GO (RGO) to h-BN with an appropriate reduction procedure. When a thermally conductive yet electrically insulating BN/GO/CNC (mass ratio 76/5/19) film was reduced by hydrazine, it showed thermal conductivity of 107.6 W·m^-1·K^-1 and resistivity over 10⁹ Ω·cm. On the other hand, an RGO/BN/carbonized CNC nanorods (CNR) (mass ratio 7.5/4.0/1.0) film which was annealed at 1500 °C exhibited thermal conductivity of 2,037.9 W·m^-1·K^-1 and electrical conductivity of 1,930.5 S·cm^-1. These improvements were attributed to the conductive network consisting of RGO, h-BN and CNR. This research would provide a new platform for development of the next-generation thermal management materials.

高效的热管理材料在电子芯片，LED灯和电热加热的散热方面越来越受到关注。本文中，我们通过组装氧化石墨烯（GO）和六方氮化硼（h-BN）纳米片，明智地设计和合成了具有可调电导率的导热纳米复合材料薄膜。具体地说，通过混合和搅拌GO和BN / CNC分散体制备的GO / BN /纤维素纳米晶体（CNC）杂化分散体通过蒸发诱导的自组装转变为宏观薄膜。纤维素纳米晶体（CNC）在组装过程中起着关键作用，因为它们充当h-BN纳米片的分散剂并在h-BN和GO之间形成手性结构连接。通过适当的还原程序，通过还原GO（RGO）与h-BN的不同比例来调节热和电性能。当用肼还原导热但电绝缘的BN / GO / CNC（质量比76/5/19）膜时，其导热系数为107.6 W·m^-1 ·K ^-1和电阻率超过10 ⁹ Ω·cm以下。在另一方面，一个RGO / BN /碳化CNC纳米棒（CNR）（质量比7.5 / 4.0 / 1.0）膜，其在1500℃下退火表现出2,037.9·W·米的热传导率^-1 ·K ^-1和导电性1,930.5 S·cm ^-1。这些改进归因于由RGO，h-BN和CNR组成的导电网络。该研究将为开发下一代热管理材料提供一个新的平台。