A flexible, robust and multifunctional montmorillonite/aramid nanofibers@MXene electromagnetic shielding nanocomposite with an alternating structure for enhanced Joule heating and fire-resistant protective performance.

With the rapidly increasing development of portable devices and flexible electronic devices, multifunctional composites with excellent mechanical strength, great electromagnetic interference shielding, great Joule heating performance and strong fire-resistant protective performance are noticeably required. Herein, inspired by the sandwich structure, we have designed a montmorillonite/aramid nanofibers@MXene (MMT/ANFs@MXene) nanocomposite with an alternating multilayered structure via a simple AVF process. In this nanocomposite, the ANFs/MMT (AT) layer acts as a mechanically reinforced and insulation protection layer, while the MXene layer maintains a complete conductive network. The superior alternating multilayered structure endows the nanocomposite with outstanding mechanical properties (154.66 MPa, 14.22%) and excellent EMI shielding effectiveness values (58.4 dB). In addition, the fire-resistant protective performance of the nanocomposite improves its safety and reliability, especially, the EMI shielding effectiveness is maintained at ∼34 dB after burning for 30 s. Besides, the MMT/ANFs@MXene nanocomposite shows excellent Joule heating performance with a fast thermal response, low driving voltage and long-time temperature stability, which could reach 110.2 °C at only 3 V applied voltage within 10 s. As a result, this work presents a novel strategy for constructing multifunctional composites with outstanding overall performance, which will broaden application areas and prospects in thermal management and EMI shielding in wearable products.