Mannitol enhanced thermal conductivity and environmental stability of highly aligned MXene composite film

Multifunctional thermal management materials with high flexibility are urgently required to tackle the heat dissipation issues of highly integrated electronics. MXene is considered a promising two-dimensional (2D) material for preparing composite with high thermal conductivity. However, there still is a challenge to prepare highly aligned MXene composite for simultaneously achieving high thermal performance and excellent mechanical properties. Herein, a novel MXene composite film was synthesized by vacuum-assisted filtering MXene nano-sheets suspension containing non-toxic and pollution-free mannitol. Under the connection of mannitol, MXene nano-sheets in the MXene/mannitol composite film form a highly aligned structure, resulting in outstanding thermal and mechanical properties. In-plane and through-plane thermal conductivities are 36.3 and 1.06 W m−1 K−1 for the MXene/mannitol composite film prepared using MXene suspension with a mannitol content of 0.2 mol/L, which are higher by 172% and 193% than those of pure MXene film, respectively. As the heat sink for a high-power LED, the MXene/mannitol composite film also demonstrated an excellent heat dissipation efficiency outperforming pure MXene film. Moreover, the MXene/mannitol composite film exhibited noteworthy mechanical property and stable thermal conductivity after bending for 300 times. Our findings provide a promising approach to prepare high-performance heat spreader for the thermal management of modern electronic components.