Flexible sandwich-structured MXene@CNT/SA@MXene film with high electromagnetic shielding performance

The composite films with flexible and high electromagnetic-shielding (EMI) performance have been attracting more and more attention. Herein, using MXene as an interlayer and carbon nanotube/sodium alginate (CNT/SA) as a core layer, a flexible and high EMI MXene@CNT/SA@MXene (MCS) film with a sandwich structure was successfully prepared via alternating vacuum filtration. The optimal MCS film was obtained with a MXene dosage of 15 mg, a CNT/SA dosage of 6 mg and a CNT:SA mass ratio of 6:4. The thickness of the MCS film had a linear relation with the MXene and CNT/SA dosages. The best MCS film was 12 μm thick and exhibited an EMI total electromagnetic wave efficiency ( SE T ) of 61.3 dB, SSE / t of 2.34 × 10 5  dB cm 2  g −1 and conductivity of 1.74 × 10 5 S m −1 . The breaking strength, breaking elongation and toughness of MCS film increased by 24.3%, 16.7%, and 40.0% in comparison with pure MXene film, and by 40.3%, 40.0%, and 100% in comparison with MXene/CNT/SA blend film, respectively.