Multifunctional MXene-Based Fireproof Electromagnetic Shielding Films with Exceptional Anisotropic Heat Dissipation Capability and Joule Heating Performance

The burgeoning development of wearable electronic devices has resulted in urgent demands for electromagnetic interference (EMI) shielding films that feature excellent fireproof and heat dissipation capability. Herein, multifunctional fireproof EMI shielding films with excellent anisotropic thermal conductivity are constructed based on MXene and montmorillonite (MMT) via a simple vacuum-assisted filtration technique. The presence of MMT can protect the MXene from oxidation and endow the composite films with exceptional fire-resistant ability. The impressive thermal conductivity performance, high in-plane thermal conductivity (28.8 W m^–1 K^–1) and low cross-plane thermal conductivity (0.27 W m^–1 K^–1), ingeniously enables highly efficient in-plane heat dissipation and cross-plane heat insulation in the MXene-based films simultaneously. The high electrical conductivity (4420 S m^–1) of the composite film enables an excellent EMI shielding effectiveness of over 65 dB in the entire X-band and a high specific shielding effectiveness of over 10 000 dB cm² g^–1 at a thickness of only 25 μm. Importantly, the EMI shielding effectiveness is maintained at above 60 dB even after burning for 30 s. Besides, the composite films show outstanding Joule heating performance with a fast thermal response (<10 s) and a low driving voltage (<5 V). These multifunctional films are highly promising for applications concerning fire protection, de-icing, heat dissipation/insulation, and EMI shielding devices.