A porous electrically and thermally conductive composite film for heat dissipation and electromagnetic interference shielding

MXene, as an emerging graphene-like 2D material, has exhibited excellent electromagnetic interference (EMI) shielding performance because of its outstanding electrical conductivity, multiple interfaces, low density, and easy structure-constructing feature. However, the easy to stack for the 2D structure will seriously weaken the attenuation of electromagnetic waves, and heighten the secondary reflection because of high conductivity. Herein, we prepared the 3D porous MXene@fractal Ag micro-dendrites (Ag FDs) composite films by using vacuum filtration method that is induced by K ions, and then used the freeze-drying way to construct the 3D porous structure. The introduction of Ag FDs into the system can significantly improve the electrical conductivity and thermal conductivity. Additionally, the design of porous structure dramatically enhanced the multiple dissipation of electromagnetic waves, thereby augmenting the EMI shielding performance. The obtained porous composite film (thickness: 55 μm) with only 20 wt% Ag FDs delivers an outstanding EMI shielding effectiveness (SE) of 69 dB with an excellent specific EMI SE (1.25 × 10⁴ dB cm² g⁻¹), and a distinguished thermal conductivity of 26.6 W m⁻¹ K⁻¹. This porous MXene@Ag FDs composite film demonstrates exceptional EMI shielding and thermal transport properties, offering new strategies for integrating EMI shielding with thermal management.