Tailored carbon-based aramid nanofiber nanocomposites with highly anisotropic thermal conductivity and superior mechanical properties for thermal management

Polymer nanocomposites show great potential as thermal management materials owing to their light weight and high design freedom. However, they often suffer from the inability of integrating a high thermal conductivity, satisfactory mechanical properties, and even elevated temperature resistance for real-world scenarios. Here we tailor high-performance carbon-based aramid nanofiber (ANF) nanocomposites toward highly anisotropic thermal conductivity and superior mechanical properties through a vacuum-filtration-induced self-assembly process. The as-obtained ANF nanocomposite films exhibit a unique hierarchical structure composed of horizontally stacked carbon fillers in the ANF matrix, thereby achieving a high in-plane thermal conductivity of 20.54 Wm−1K−1 at only 20 wt% graphene nanosheet loading and anisotropy factors of over 100. Further finite element simulations and proof-of-concept applications for high-power light-emitting diode chip cooling demonstrate the excellent heat dissipation performance of the resulting nanocomposite film. More importantly, the tailored ANF nanocomposite films exhibit high mechanical robustness, high flexibility, superb thermal stability, and flame retardancy, making them extremely promising for thermal management applications in various electronic devices.