Advances and challenges in flexible electromagnetic protection materials for electromagnetic interference shielding and wave absorption

In this paper, we report ultralight carbon-nanotube (CNT)-infused materials with high electromagnetic shielding and absorption performance over an ultrabroadband frequency range. By controlling the CNT content and thickness of ultralight aerogels composed of CNTs during fabrication, their electromagnetic shielding/absorbing performance can be tuned over a wide frequency range (5.6–110 GHz). Samples with 40 wt% CNTs exhibit excellent shielding performance in an intensity range of 30–90 dB in all frequency ranges. Samples with less than 5 wt% CNTs show improved electromagnetic wave absorption performance of more than 10 dB. In addition, in samples with 2 and 4 wt% CNTs, strong absorption of over 25 dB occurs at certain frequencies. These CNT aerogels, which are ultralight (bulk density: 10 mg cm−3) and exhibit good mechanical properties, are expected to become a new material for electromagnetic shielding and absorption in advanced engineering applications.

A quantitative permittivity model for designing electromagnetic wave absorption materials with conduction loss: A case study with microwave-reduced graphene oxide

The vital application of rare earth for future high-performance electromagnetic wave absorption materials: A review

Metal–organic frameworks (MOFs) derivatives are developing family of functional materials for electromagnetic wave (EMW) absorption. Their tailored structures, controllable compositions, high porosity, and versatile functions offer immense advantages for the construction of excellent EMW absorption materials. Nevertheless, it is crucial and challenging to understand the unique role of rationally designing art and tailoring the microstructures of MOF‐derived materials for EMW absorption. In this review, advances in rational architectural design strategy and the elaborate control of microstructures are outlined to promote the EMW absorption performance of MOF‐derived materials. In addition, the derived key information regarding the superiority and composition–structure–performance relationships of the engineered MOF‐derived materials with advanced components and nanostructures is comprehensively summarized. Finally, the insight into the challenges of future development in MOF‐derived EMW absorption materials is presented.

Bridging microscopic phase and defect manipulation with macroscopic core-sheath-shell structure for polarization-dominated electromagnetic wave absorption

To meet the rigorous demands placed on electromagnetic (EM) wave absorbing (EWA) materials by harsh service conditions and to reduce EM wave power density, the development of ceramic‐based EWA materials with high reliability and stability has become a subject of significant focus. In this study, yttrium silicide carbide interphase was in situ synthesized on silicon carbide fibers to fabricate Y₃Si₂C₂–SiC f composite fibers by the molten salt method. These fibers were then incorporated into a mullite ceramic matrix, and Y₃Si₂C₂–SiC f /mullite composites were prepared by gel injection molding, aiming at enhancing the EWA properties. The Y₃Si₂C₂–SiC f /mullite composite exhibited a reflection loss of −28.97 dB at 2.44 mm thickness and an effective absorption bandwidth of 3.066 GHz, outperforming pure mullite and SiC f /mullite composites due to the addition of Y₃Si₂C₂–SiC f . A modified Drude–Lorentz model was developed to capture the multi‐peak permittivity behavior of Y₃Si₂C₂–SiC f /mullite composites. The results showed that dipole relaxation and hopping migration of localized electrons played key roles in the overall microwave energy attenuation, which closely matched the experimental data. Furthermore, simulations of the electric field distribution and radar cross‐section confirmed the superior energy loss capability and practical application potential of Y₃Si₂C₂–SiC f /mullite composites. This study offers valuable theoretical insights into the design and application of SiC f ‐reinforced ceramic‐based EWA materials.

Widespread electromagnetic (EM) interference and pollution have become major issues due to the rapid advancement of fifth-generation (5G) wireless communication technology and devices. Recent advances in high-entropy (HE) materials have opened new opportunities for exploring EM wave absorption abilities to address the issues. The lattice distortion effect of structures, the synergistic effect of multi-element components, and multiple dielectric/magnetic loss mechanisms can offer extensive possibilities for optimizing the balance between impedance matching and attenuation ability, resulting in superior EM wave absorption performance. This review gives a comprehensive review on the recent progress of HE materials for EM wave absorption. We begin with the fundamentals of EM wave absorption materials and the superiority of HE absorbers. Discussions of advanced synthetic methods, in-depth characterization techniques, and electronic properties, especially with regard to regulatable electronic structures through band engineering of HE materials are highlighted. This review also covers current research advancements in a wide variety of HE materials for EM wave absorption, including HE alloys, HE ceramics (mainly HE oxides, carbides, and borides), and other novel HE systems. Finally, insights into future directions for the further development of high-performance HE EM wave absorbers are provided.

Construction of CoFe2O4/MXene hybrids with plentiful heterointerfaces for high-performance electromagnetic wave absorption through dielectric-magnetic cooperation strategy

Smart shape memory composite foam enabled rapid and conformal manipulation of electromagnetic wave absorption performance

Construction of three-dimensional porous network Fe-rGO aerogels with monocrystal magnetic Fe3O4@C core-shell structure nanospheres for enhanced microwave absorption

Excellent electromagnetic wave loss and impedance matching are typical characteristics of superior‐performance electromagnetic wave (EMW) absorption materials. Changing the component ratios and multidimensional combinations of various absorbing materials is one of the best methods to improve absorption performance. This work used a convenient physical mixing approach to combine three wave‐absorbing materials with various dimensions to successfully prepare Graphene/carbon nanotubes/Fe3O4 (G/C/Fe3O4)/paraffin composites. One‐dimensional (1D) tube carbon nanotubes (CNTs) pierced two‐dimensional (2D) sheet graphene to form a strong three‐dimensional (3D) conductive network, enhancing interfacial polarization without introducing zero‐dimensional (0D) magnetic Nano‐Fe3O4. Nevertheless, because of their significant dielectric characteristics, the graphene/carbon nanotube (G/C) paraffin composites displayed low impedance matching and electromagnetic wave absorption properties. At a mass ratio of 1:1, the G/C/paraffin composites achieved an ideal reflection loss (RL) of −11.99 db and an impedance matching value of 0.59. Adding Fe3O4 improved the impedance matching and electromagnetic wave loss performance and promoted the formation of a non‐homogeneous interface, improving interfacial polarization and reflection. The G/C/Fe3O4/paraffin composite, with a mass ratio of 1:1:6 and a filler ratio of 20%, achieved an optimum reflection loss of −37.2 dB and an effective absorption bandwidth of 4.16 GHz. This work optimized and improved the performance of EMW materials practically and rapidly, providing a research method for the widespread application of superior‐performance electromagnetic wave absorption materials.Highlights The EMW absorption materials with various architectures. 1D CNTs pierced 2D sheet graphene to form a strong 3D conductive network. Adding Fe3O4 promoted the formation of a non‐homogeneous interface. Electromagnetic synergies and different structural combinations It achieved excellent impedance matching and electromagnetic loss performance.

Flexible electromagnetic wave absorption material: Multiscale synergistic approach to achieve whole X-band absorption and thermal stealth property

The electromagnetic (EM) devices have been widely used in communication, electrical engineering, and medical care. However, EM device is a double-edged sword for its convenience is followed by signal pollution and radiation. Electromagnetic interference (EMI) combat has brought lots of attention to researchers in this field. Researchers have made great efforts in developing electromagnetic wave absorbing and shielding (EMAS) materials to reduce EM wave power density to solve the above problem. However, the great majority of reported EMAS materials are powders and coatings, which possess merely EMAS property. Modern practical application has abundant multiple scenes, including high temperature, intense light, water flow, etc. Under the circumstances, EMAS materials should be functionalized with outstanding tunable absorption bands. Based on field theory in physics, multiexternal fields-responsive materials are an effective method to deal with the above urgently unsolved problem. Thus, herein, different external field-responsive materials, including temperature, light, space-time, electrical, wind, density, and flow fields, are focused on. Various action mechanisms, materials synthesis methods, and different macrostructures are summarized in detail. Meanwhile, the developing trends of novel external field-responsive materials are also discussed in order. Finally, the challenges of designing new type of EMAS devices are mentioned.

Plentiful heterogeneous interfaces coupling in hydrangea-like NiMn-LDH decorated MXene hybrids for enhancing electromagnetic wave absorption

Nanofibrous membrane constructed magnetic materials for high-efficiency electromagnetic wave absorption