MoS₂ Lubricate-Toughened MXene/ANF Composites for Multifunctional Electromagnetic Interference Shielding

The design and fabrication of high toughness electromagnetic interference (EMI) shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem. Ternary MXene/ANF (aramid nanofibers)-MoS₂ composite films with nacre-like layered structure here are fabricated after the introduction of MoS₂ into binary MXene/ANF composite system. The introduction of MoS₂ fulfills an impressive "kill three birds with one stone" improvement effect: lubrication toughening mechanical performance, reduction in secondary reflection pollution of electromagnetic wave, and improvement in the performance of photothermal conversion. After the introduction of MoS₂ into binary MXene/ANF (mass ratio of 50:50), the strain to failure and tensile strength increase from 22.1 $\pm$ 1.7% and 105.7 $\pm$ 6.4 MPa and to 25.8 $\pm$ 0.7% and 167.3 $\pm$ 9.1 MPa, respectively. The toughness elevates from 13.0 $\pm$ 4.1 to 26.3 $\pm$ 0.8 MJ m^-3 (~ 102.3%) simultaneously. And the reflection shielding effectiveness (SE_R) of MXene/ANF (mass ratio of 50:50) decreases ~ 10.8%. EMI shielding effectiveness (EMI SE) elevates to 41.0 dB (8.2-12.4 GHz); After the introduction of MoS₂ into binary MXene/ANF (mass ratio of 60:40), the strain to failure increases from 18.3 $\pm$ 1.9% to 28.1 $\pm$ 0.7% (~ 53.5%), the SE_R decreases ~ 22.2%, and the corresponding EMI SE is 43.9 dB. The MoS₂ also leads to a more efficient photothermal conversion performance (~ 45 to ~ 55 °C). Additionally, MXene/ANF-MoS₂ composite films exhibit excellent electric heating performance, quick temperature elevation (15 s), excellent cycle stability (2, 2.5, and 3 V), and long-term stability (2520 s). Combining with excellent mechanical performance with high MXene content, electric heating performance, and photothermal conversion performance, EMI shielding ternary MXene/ANF-MoS₂ composite films could be applied in many industrial areas. This work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers.