High Thermally Conductive and Mechanically Strong Aramid Nanofiber Composite Film by a Single-Walled Carbon Nanotube and Ti₃C₂T_<i>x</i> MXene for Electromagnetic Shielding and Thermal Management

Currently, the development of electromagnetic shielding materials with both mechanical strength and high thermal conductivity for next-generation electronic devices remains a challenge. In this study, we developed single-walled carbon nanotube (SWCNT)/MXene/aramid nanofiber (ANF) composite films, with a “brick-and-mortar” structure, by vacuum filtration and a hot-pressing method. This structure enables the composite film to enhance the mechanical and thermal performance while maintaining a satisfied electromagnetic shielding function. Particularly, the low-temperature plasma-treated SWCNTs were utilized to significantly overcome the interface resistance, where strong hydrogen bonds with ANFs have been confirmed. The results indicated that the composite film achieved a tensile strength of 281.2 MPa and an elongation at break of 17.6%. The combination of SWCNTs and Ti3C2Tx MXene forms a three-dimensional thermal conduction network, resulting in an exceptional thermal conductivity of 14.99 W/m·K for the SWCNT/MXene/ANF composite film, which is 571% higher than that of a pure ANF film. The “brick-and-mortar” structure results in continuous absorption and attenuation of electromagnetic waves, allowing the electromagnetic shielding effectiveness to reach around 31.9 dB. Overall, the strategy proposed in this work has shown positive potential multifunctional electromagnetic shielding materials with good mechanical and thermal performance.