▎ 摘　　要

Polymer composites with high thermal conductivity and good electrical insulation property exhibit great potential applications in electronic packing field. Herein, we report a composite film through functional Al2O3 (f-Al2O3) deposited graphene as fillers to regulate both the thermal conductivity and the electrical insulation property of nanofibrillated cellulose (NFC). The bridging effect of f-Al2O3 among graphene increased the number of heat conduction paths, thus improved the thermal conductivity of obtained f-Al2O3@RGO/NFC composite. The maximum in-plane thermal conductivity of obtained composite film is up to 8.3 W m(-1) K-1, representing the enhancement of 1975% compared with the pure NFC. At the same time, owing to the inherent insulating property of Al2O3, the composite exhibited excellent electrical insulation property due to the inherent insulation property of Al2O3. This facile and scalable strategy could pave the way for the fabrication of thermal management materials in the next-generation electrical packing field.