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Highlights: Co/Co3O4@NC nanosheets with gradient magnetic heterointerfaces have been fabricated by the high-temperature carbonization/low-temperature oxidation processes. Experimental and theoretical simulation results indicate that magnetic heterointerfaces engineering is beneficial for optimizing impedance matching and promoting electromagnetic wave absorption. Gradient magnetic heterointerfaces with magnetic-heteroatomic components realize the adjustment of interfacial polarization, magnetic coupling, and long-range magnetic diffraction. Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching, adjusting dielectric/magnetic resonance and promoting electromagnetic (EM) wave absorption, but still exist a significant challenging in regulating local phase evolution. Herein, accordion-shaped Co/Co3O4@N-doped carbon nanosheets (Co/Co3O4@NC) with gradient magnetic heterointerfaces have been fabricated via the cooperative high-temperature carbonization and low-temperature oxidation process. The results indicate that the surface epitaxial growth of crystal Co3O4 domains on local Co nanoparticles realizes the adjustment of magnetic-heteroatomic components, which are beneficial for optimizing impedance matching and interfacial polarization. Moreover, gradient magnetic heterointerfaces simultaneously realize magnetic coupling, and long-range magnetic diffraction. Specifically, the synthesized Co/Co3O4@NC absorbents display the strong electromagnetic wave attenuation capability of − 53.5 dB at a thickness of 3.0 mm with an effective absorption bandwidth of 5.36 GHz, both are superior to those of single magnetic domains embedded in carbon matrix. This design concept provides us an inspiration in optimizing interfacial polarization, regulating magnetic coupling and promoting electromagnetic wave absorption. [ABSTRACT FROM AUTHOR]

Multifunctionalization of electromagnetic wave absorbing materials (EMWAMs) presents a promising avenue for their application in complex scenarios. However, the effective integration of multiple supplementary functions into EMWAMs continues to pose a significant challenge. Herein, a novel nanofiber elastomer (NFE) incorporating multicomponent inorganic FeS2/S,N co‐doped carbon nanofibers (NFs) and organic component (Ecoflex) are designed and synthesized. The sulfur doping ratios and species can be effectively modulated via controlling the amount of sulfur and sulfurization temperature. The optimized FeS2/S,N co‐doped carbon NFs/Ecoflex NFE not only exerted an excellent impedance matching characteristic, but also displays boosted conductive loss and polarization loss capacities. Amongst, the designed NFE achieved an ultra‐wide effective absorption bandwidth (EAB) of 7.40 GHz and minimum reflection loss (RLmin) of −21.82 dB at the thin matching thickness (≈2.00 mm). Furthermore, FeS2/S,N co‐doped carbon NFs/Ecoflex NFE simultaneously presents greatly improved mechanical property, thermal insulation, hydrophobicity, and corrosion resistance. Through designing metastructures, the NFE with a periodically closed‐ring resonant structure realized an EAB of 32.64 GHz (ranging from 7.36 to 40.00 GHz). Overall, this research contributes valuable insights for the design of next‐generation EMWAMs with satisfactory multifunctionalities, demonstrating their significant potential for application in smart devices and challenging environments. [ABSTRACT FROM AUTHOR]

The popularity of portable and wearable flexible electronic devices, coupled with the rapid advancements in military field, requires electromagnetic interference (EMI) shielding materials with lightweight, thin, and flexible characteristics, which are incomparable for traditional EMI shielding materials. The film materials can fulfill the above requirements, making them among the most promising EMI shielding materials for next‐generation electronic devices. Meticulously controlling structure of composite film materials while optimizing the electromagnetic parameters of the constructed components can effectively dissipate and transform electromagnetic wave energy. Herein, the review systematically outlines high‐performance EMI shielding composite films through structural design strategies, including homogeneous structure, layered structure, and porous structure. The attenuation mechanism of EMI shielding materials and the evaluation (Schelkunoff theory and calculation theory) of EMI shielding performance are introduced in detail. Moreover, the effect of structure attributes and electromagnetic properties of composite films on the EMI shielding performance is analyzed, while summarizing design criteria and elucidating the relevant EMI shielding mechanism. Finally, the future challenges and potential application prospects of EMI shielding composite films are prospected. This review provides crucial guidance for the construction of advanced EMI shielding films tailored for highly customized and personalized electronic devices in the future. [ABSTRACT FROM AUTHOR]

Electromagnetic interference (EMI) shielding materials with low electromagnetic (EM) waves reflection characteristics are ideal materials for blocking EM radiation and pollution. Materials with low reflectivity must be constructed using materials with excellent EM waves absorption properties. However, materials simultaneously possessing both low reflectivity and excellent EMI shielding performance remain scarce, consequently, multilayer structures need to be developed. Poly(p-phenylene-2,6-benzobisoxazole) nanofibers (PNF) are prepared by deprotonation. PNF are combined with MXene and heterostructure MXene@Ni prepared by in-situ growth; MXene@Ni/PNF acts as an EM absorption layer while MXene/PNF acts as an EM reflective layer. Finally, (MXene@Ni/PNF)-(MXene/PNF) aerogels are prepared by layer-by-layer freeze-drying based on the layered modular design concept. Experimental characterizations revealed that (MXene@Ni/PNF)-(MXene/PNF) aerogels enable the efficient absorption-reflection-reabsorption of EM waves, effectively eliminating EMI. When the mass ratio of MXene to Ni in MXene@Ni is 1:6 and the mass fraction of MXene in the reflective layer is 80 wt.%, the (MXene@Ni/PNF)-(MXene/PNF) aerogels exhibit excellent EMI shielding performance (71 dB) and a very low reflection coefficient (R = 0.10). Finite element simulations verified that the developed asymmetric structural aerogels achieve high EMI shielding performance with low reflection characteristics. In addition, (MXene@Ni/PNF)-(MXene/PNF) aerogels display excellent infrared camouflage ability., (© 2024 Wiley‐VCH GmbH.)

The low thermal conductivity, poor toughness, and non-reprocessability of thermosetting epoxy resins severely restrict their applications and sustainable development in flexible electronics. Herein, liquid crystalline epoxy (LCE) and dynamic ester and disulfide bonds are introduced into the cured network of bisphenol A epoxy resin (E-51) to construct highly thermally conductive flexible liquid crystalline epoxy resin (LCER) vitrimers. LCER vitrimers demonstrate adjustable mechanical properties by varying the ratio of LCE to E-51, allowing it to transition from soft to strong. Typically, a 75 mol% LCE to 25 mol% E-51 ratio results in an in-plane thermal conductivity (λ) of 1.27 W m -1 K -1 , over double that of pure E-51 vitrimer (0.61 W m -1 K -1 ). The tensile strength and toughness increase 2.88 folds to 14.1 MPa and 2.45 folds to 20.1 MJ m -3 , respectively. Besides, liquid crystalline phase transition and dynamic covalent bonds enable triple shape memory and three-dimensional shape reconstruction. After four reprocessing cycles, λ and tensile strength remain at 94% and 72%, respectively. Integrating carbon nanotubes (CNTs) imparts photo-thermal effect and enables "on" and "off" switch under near-infrared light to LCER vitrimer. Furthermore, the CNTs/LCER vitrimer displays light-induced actuation, self-repairing, and self-welding besides the closed-loop recycling and rapid degradation performance., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Currently, the demand for electromagnetic wave (EMW) absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent. Multi-component interface engineering is considered an effective means to achieve high-efficiency EMW absorption. However, interface modulation engineering has not been fully discussed and has great potential in the field of EMW absorption. In this study, multi-component tin compound fiber composites based on carbon fiber (CF) substrate were prepared by electrospinning, hydrothermal synthesis, and high-temperature thermal reduction. By utilizing the different properties of different substances, rich heterogeneous interfaces are constructed. This effectively promotes charge transfer and enhances interfacial polarization and conduction loss. The prepared SnS/SnS 2 /SnO 2 /CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt% in epoxy resin. The minimum reflection loss (RL) is - 46.74 dB and the maximum effective absorption bandwidth is 5.28 GHz. Moreover, SnS/SnS 2 /SnO 2 /CF epoxy composite coatings exhibited long-term corrosion resistance on Q235 steel surfaces. Therefore, this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments., (© 2024. The Author(s).)