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.

The high power density and intelligence of next-generation flexible electronic devices bring many challenges to fabricate flexible composite films with electromagnetic interference (EMI) shielding effectiveness (SE) property and excellent toughness via a simple method. Herein, inspired by the layered structure and biopolymer matrix networks in natural nacre, nacre-like layered Ti₃C₂T_x (MXene)/aramid nanofiber (ANF) films were fabricated through sol-gel, vacuum-assisted filtration, and hot-pressing. Three-dimensional (3D) interconnected aramid nanofibers networks between adjacent layered MXene result in an ultralong strain-to-failure of the film. Even though the functional filler MXene contents are as high as 60 wt.% and 70 wt.%, the strain-to-failure of the films could reach astonishing values of 18.34% ± 1.86% and 14.43% ± 1.26%, respectively. And the tensile strength could maintain about 85 MPa. Excitingly, with such a high filler, the film can also withstand double folding and vigorous rubbing without damage, which could better adapt to a harsh application environment. The result means that this work provides a convenient way to prepare other high functional filler composite films with excellent mechanical performance. The EMI SE values could reach 45 and 52.15 dB at 60 wt.% and 70 wt.% MXene in 8.2–12.4 GHz. Meanwhile, the films have prominent Joule heating properties, high sensitivity (< 15 s), small voltage operation (0.5 V), and high operation constancy (1300 s). Therefore, nacre-inspired MXene/ANF composite films in this work have ability to apply in many areas including communication technology, military, and aerospace.

Energy has increasingly become the material basis for the development of human society and occupies a strategic position in the national economy. Single-atom catalysts (SACs) are widely recognized as promising catalysts in the chemical and energy industries. Therefore, it is of great practical significance to develop SACs with ideal intrinsic activity, high stability, and low cost. Compared with traditional M–N₄ active sites, metal–nitrogen–carbon (M–N–C) catalysts with asymmetric coordination structures have been rapidly developed in the field of catalysis. This could be attributed to their unique electronic and geometric structures, making asymmetric coordination a novel and attractive strategy. In this paper, several typical asymmetric M–N–C SACs are summarized, namely asymmetric M–N_x SACs, asymmetric M–N_x–O/S/P/B/Cl/I SACs and asymmetric M–M SACs. The research development and application of these advanced catalysts in electrocatalytic reactions such as the oxygen reduction reaction (ORR), CO₂ reduction reaction (CO₂RR), hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and nitrogen reduction reaction (NRR) are systematically illustrated.

Currently, the development of low-reflection electromagnetic interference (EMI) shielding composite materials for mitigating secondary electromagnetic wave pollution has become a major research focus. However, achieving thinness, high toughness, low reflectivity, and multifunctionality in flexible EMI shielding films remains a challenge. To address this issue, this study introduces a "magnetic-electric" Janus structure EMI shielding composite film composed of MXene nanosheets, carbonized ZIF67 (CZIF67) nanoparticles and aramid nanofibers (ANF), balancing thinness, high toughness, low reflectivity and multifunctionality. As a result, the MXene/ANF-CZIF67/ANF-4 (MACA-4) sample exhibits high tensile strength (110.0 ± 7.0 MPa), large strain tolerance (21%), and superior toughness (14.9 ± 0.9 MJ·m^-³), reflecting the stress dispersion effect of the 3D network structure of ANF and the strengthening effect of hydrogen bonding. The sample exhibits excellent flexibility, resistance to rubbing and folding. Even with a thickness of only 80 μm, the MACA-4 film exhibits a reflection performance (SE_R) as low as 4.3 to 4.5 dB in the 8.2 to 9.6 GHz band and the SE_T in the X-band reaches 44.8 dB. In addition, the superior conductivity of the MXene/ANF layer and the localized surface plasmon resonance effect give the MACA composite films excellent electrothermal conversion capabilities. Surprisingly, the sample also exhibited excellent infrared stealth and fire alarm properties. This work offers valuable guidance on the fabrication of ultra-thin flexible EMI shielding composites and provides an important scientific basis for the design and application of efficient EMI shielding materials.