Graphene Paper‐Based Multilayer Thermally Conductive Tapes with Exceptional Electrical Insulation for High Heat Flux Dissipation

Abstract The rapid increase in power density and the more limited space in compact electronic devices necessitate highly thermally conductive yet electrically insulating tapes for heat dissipation. However, state‐of‐the‐art tapes have an in‐plane thermal conductivity ( κ _// ) lower than 70 W m ⁻¹ K ⁻¹ when the thickness exceeds 200 µm, limiting their applications in high heat flux devices. Herein, a multilayer, highly thermally conductive yet electrically insulating tape (MTCEIT) is developed by sandwiching graphene paper within boron nitride nanosheet‐filled polymer nanocomposite adhesives and in series combining it with a boron nitride flake‐filled polymer composite film. At ≈300 µm thickness, the MTCEIT exhibits an ultrahigh κ _// of 121.22 W m ⁻¹ K ⁻¹ , while maintaining a volume electrical resistivity of 5.07 × 10 ¹¹ Ω·cm and a Weibull characteristic breakdown strength of 36.9 kV mm ⁻¹ . The multilayer structure endows the MTCEIT with exceptional electrical insulation and highly efficient heat dissipation capability, which can reduce the equilibrium temperature of a central processing unit (CPU) by 9 °C in a thin laptop and stabilize the video frame rate (fluctuation ≤ 0.1 fps) of an ultrathin smartphone without forced cooling. This study provides an innovative solution to the challenge of dissipating high heat flux in compact electronic devices.