High Thermally Conductive and Mechanically Strong Aramid Nanofiber Composite\nFilm by a Single-Walled Carbon Nanotube and Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene for Electromagnetic Shield

Currently,\nthe development of electromagnetic shielding materials\nwith both mechanical strength and high thermal conductivity for next-generation\nelectronic devices remains a challenge. In this study, we developed\nsingle-walled carbon nanotube (SWCNT)/MXene/aramid nanofiber (ANF)\ncomposite films, with a “brick-and-mortar” structure,\nby vacuum filtration and a hot-pressing method. This structure enables\nthe composite film to enhance the mechanical and thermal performance\nwhile maintaining a satisfied electromagnetic shielding function.\nParticularly, the low-temperature plasma-treated SWCNTs were utilized\nto significantly overcome the interface resistance, where strong hydrogen\nbonds with ANFs have been confirmed. The results indicated that the\ncomposite film achieved a tensile strength of 281.2 MPa and an elongation\nat break of 17.6%. The combination of SWCNTs and Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene forms a three-dimensional\nthermal conduction network, resulting in an exceptional thermal conductivity\nof 14.99 W/m·K for the SWCNT/MXene/ANF composite film, which\nis 571% higher than that of a pure ANF film. The “brick-and-mortar”\nstructure results in continuous absorption and attenuation of electromagnetic\nwaves, allowing the electromagnetic shielding effectiveness to reach\naround 31.9 dB. Overall, the strategy proposed in this work has shown\npositive potential multifunctional electromagnetic shielding materials\nwith good mechanical and thermal performance.