Electromagnetic Wave Absorption Research Articles

Facile synthesis of Fe3O4/Ti3C2Tx MXene/RGO aerogels with broadband microwave absorption and thermal insulation performance

Abstract The development of microwave absorbing materials with attributes such as low weight, broad absorption bandwidth, and superior thermal insulation performance is still challenging. In this study, Fe3O4 nanoparticles were anchored on Ti3C2Tx MXene/RGO nanosheets by one-step hydrothermal gelation method to prepare Fe3O4/Ti3C2Tx MXene/RGO (FeMR) hybrid aerogels. Perfect impedance matching and electromagnetic coupling effect were achieved by adjusting the composition ratio of FeMR aerogels, so exceptionally outstanding microwave absorption performance was obtained. FeMR aerogel at 2.90 mm thickness, effective absorption bandwidth (EAB) up to 8.10 GHz. Simultaneously, FeMR aerogels have has good thermal insulation performance. After heating at 300°C for 60 min, the aerogel can still isolate the thermal radiation of about 155 °C. This work demonstrates a simple method for preparing lightweight, broadband electromagnetic wave absorption and heat insulation three-dimensional MXene-based aerogels, which provides inspiration for the structural design and potential applications of EWA materials.

Etching-time-regulated strategy toward delaminated Mo 2CT x MXene for tailoring electromagnetic wave absorption

Etching-time-regulated strategy toward delaminated Mo ₂CT <em> _x </em> MXene for tailoring electromagnetic wave absorption

In-Situ Surface Modification of Nickel Mesh for Superior Electromagnetic Interference Shielding

Metal mesh, with its inherent conductivity, transparency, and flexibility, has proven to be an exceptional choice for high-performance reflection-dominated electromagnetic interference (EMI) shielding materials, due to its multifunctionality and wide applicability. However, the development of metal-based absorption-enhanced EMI shielding materials characterized by high absorption and low reflection is crucial but remains challenging. Herein, we introduce a novel surface modification strategy for nickel mesh (NM) aimed at augmenting its surface electromagnetic wave absorption through electrochemical surface microstructure alteration and subsequent wet chemical sulphuration. This approach leverages the multiple reflections within the microporous structure and the impedance matching enhancement provided by the magnetic sulfided nickel layer, resulting in the sulphur-treated porous NM (Ni3S2-PNM) achieving an outstanding average EMI SE of 59.6 dB across a broad frequency range of 4 to 40 GHz. The surface electromagnetic wave absorption rate of Ni3S2-PNM has increased from under 1% for unmodified NM to over 60%, significantly reducing the re-reflection of electromagnetic waves back into free space (the average SER value decreases from about 20 dB to 2.2 dB). Characterized by its simplicity and cost-effectiveness, this in-situ surface modification method on bulk industrial-grade NM, enhancing electromagnetic shielding, presents a promising avenue for wider application in electromagnetic protection.

Ni doped carbon-based composites derived from waste cigarette polypropylene filter rod with electromagnetic wave absorption performance

Abstract Polypropylene is widely used in the plastics industry, especially in the tobacco industry, served as cigarette filters to reduce tar and harm. However, it’s difficult to degrade these polypropylene plastics and suitable methods for recycling and reuse is urgent. This research proposes an efficient method for the reuse of polypropylene cigarette filters by mixing waste polypropylene filters with nickel source in different proportions, followed by a facile calcination treatment to prepare nickel-modified carbon-based composite materials with excellent microwave absorption properties. Morphology and magnetic properties of as-prepared samples were analyzed via XRD, SEM, and VSM, exhibiting an increase in carbon content with raising nickel content. Nickel ion anchored on polypropylene fiber may facilitate better fixation of carbon chains during the polypropylene decomposition process. Among the as-prepared samples, CN2 exhibited superior microwave absorption performance, with an optimal absorption peak of -26.76 dB at 7.97 GHz when matched with a given thickness of 4.3 mm, and an effective absorption bandwidth of 3.64 GHz (8.04 GHz to 11.68 GHz) with a matching thickness of 3.5 mm, covering the X band. Therefore, the as-prepared microwave absorbers provides a feasible solution for the recycling and reuse of polypropylene filters, aligning with the tobacco industry requirements for green and sustainable development.&amp;#xD;

MXenes: Structure, properties, and photothermal applications

The ever-growing interest in MXenes has been driven by their unique electrical, thermal, mechanical, and optical properties. Due to the presence of diverse surface ligands and defect sites, MXenes exhibit desirable and highly tunable optical response in the solar spectrum. In addition, they have also been found to be effective shields for electromagnetic interference thanks to their selective electromagnetic wave absorption capability. These features collectively provide MXenes with promising potentials for photothermal conversion applications. However, the underlying scientific mechanisms, pathways, and potential impact of photothermal conversion by MXenes remain poorly categorized and understood. In this review, the electronic, optical, and plasmonic properties and potential photothermal mechanism of MXene materials are systematically summarized. Current advances in various photothermal applications as well as challenges and opportunities in relevant fields are also presented. This review provides comprehensive understandings on the fundamental properties as well as a guidance for in-depth investigation of the photothermal conversion mechanism.

Optimized electromagnetic wave absorption of Ag/Fe3O4/SiO2 via magnetic field-induced synthesis

This study reports on the synthesis and electromagnetic wave-absorbing properties of Ag/Fe3O4/SiO2 under various magnetic field intensities. The nanocomposites were prepared via a solvothermal method followed by a Stober proces, during which uniform magnetic fields were applied to induce the formation of one-dimensional nanochain structures. Results indicate that the Ag/Fe3O4/SiO2 exhibit enhanced wave-absorbing capabilities under strong magnetic fields. Specifically, at a magnetic field of 600 mT, the composite achieves a minimum reflection loss value of −48.61 dB, accompanied by a broad effective absorption bandwidth. Furthermore, the microwave absorption performance of samples oriented horizontally along the circumference surface during preparation shows a significant improvement compared to non-oriented samples. It is attributed to the optimized electromagnetic wave transmission pathways and improved electrical conductivity and magnetic loss capabilities facilitated by the nanochain structures. Specifically, the nanochains effectively lengthen the wave propagation distance, promote charge migration, and intensify natural and exchange resonance effects. This research not only broadens the design paradigm for electromagnetic wave-absorbing materials but also offers novel strategies for their development.

Additive manufacturing of polymer composite millimeter‐wave components: Recent progress, novel applications, and challenges

AbstractWith the advent of 5G/6G for radar and space communication systems, various millimeter‐wave (MMW) components are rapidly innovated for multi‐functional, higher integrated and miniaturized solutions across diverse industries and applications. Polymer composites‐based additive manufacturing (AM), an advanced manufacturing technique, can manufacture MMW components with high fabrication resolution, intricate structural design, adjustable dielectric properties, and functionally gradient distribution characteristics. This paper outlines the state‐of‐the‐art polymer composite MMW components, their design, and manufacturing techniques. An integrated “material‐structure‐manufacturing‐performance” design conceptual framework of polymer composite MMW components is discussed in terms of material design, structure design, and process design. Moreover, multi‐functional polymer composite MMW structures focus on electromagnetic wave absorption and electromagnetic interference (EMI) shielding functions. Moreover, novel applications of MMW polymer composite components enabled by AM on radar/sensing, communication, enclosure, and miscellaneous applications are discussed. Furthermore, future perspectives and current challenges are identified to provide new insights into multi‐functional 3D‐printed MMW products, exploring new possibilities for next‐generation advanced MMW technology.Highlights The 3D‐printed MMW components and additive manufacturing are reviewed. The integrated “material‐structure‐manufacturing‐performance” concept is introduced. 3D‐printed MMW components are discussed on radar, enclosure, and miscellaneous applications. Future perspectives and challenges of 3D‐printed MMW components are addressed.

Innovative multi-functional foamed concrete made from rice husk ash: thermal insulation and electromagnetic wave absorption

Innovative multi-functional foamed concrete made from rice husk ash: thermal insulation and electromagnetic wave absorption

The cation exchange driving multi-phase regulation in Co7Fe3/Co@NC for enhanced broadband electromagnetic wave absorption

Phase engineering offers distinctive advantages in designing efficient electromagnetic wave (EMW) absorbers. The manipulation of the interaction and arrangement of different multi-phase systems enables the achievement of more precise EMW absorption. However, the transition mechanism from single metal phases to metal/alloy phases has not yet been fully revealed. Here, we employ multiphase engineering driven by cation exchange reactions to finely control the proportion of Co/Co7Fe3 phases and regulate electromagnetic parameters. The introduction of cavities and heteroatoms through cation exchange enables optimized defect distribution and composition, which enhances both impedance matching and electromagnetic attenuation capabilities. Specifically, we yield hollow Co7Fe3/Co@N-doped carbon (H-Co7Fe3/Co@NC) embedded in high-crystallinity graphite carbon after high-temperature pyrolysis, which promotes significant electron transfer between phases, thus enhancing conduction and polarization losses. H-Co7Fe3/Co@NC exhibits ultra-strong reflection loss (RL) of −59.70 dB at 9.37 GHz and achieves broadband absorption of 6.01 GHz at 2.1 mm. This study highlights the influence of Co7Fe3/Co heterogeneous structures on absorption performance and validates the electromagnetic response mechanism of multi-phase heterostructures through COMSOL finite element simulation analysis. Thus, this work paves the way for applying multi-phase engineering driven by cation exchange reactions for advanced absorbers.

Multifunctional electromagnetic wave absorbing carbon fiber/Ti3C2TX MXene fabric with ultra-wide absorption band

In order to provide electronics and aerospace equipment with effective immunity to electromagnetic interference and to improve their adaptability to very harsh electromagnetic environments, high-performance electromagnetic wave-absorbing materials are urgently needed for civil and military applications. Unfortunately, their effective absorption bandwidth width is still unsatisfactory (<10 GHz) due to the insufficient regulation of their component mixing and microstructure. By employing nanocage-structured UiO-66 as a doping phase, MXene/ZrO2/tungsten-doped carbon (MXene/ZrO2/W-C) interpenetrating fiber networks were prepared by the electrostatic spinning method. According to the experimental results, the introduction of the dopant phase and the formation of the interpenetrating network significantly improves impedance matching, resulting in a wide absorption bandwidth of 11.12 GHz for the composites, completing the coverage of the X and Ku bands. The radar scattering cross section of MXene/ZrO2/W-C has been simulated using three-dimensional electromagnetic field simulation, and as a result of its excellent stealth performance, it is able to generate corresponding electromagnetic responses in radar detection environments that exhibit different far-field emission bands. Further, MXene/ZrO2/W-C exhibits outstanding hydrophobicity, corrosion resistance, and temperature resistance. These characteristics allow it to be used for the preparation of electromagnetic wave (EMW) absorbing devices for complex environmental applications. It is important to note that the results of this study will be extremely useful in the development of composites based on MXene with ultra-wide absorption bands as well as in the analysis of EMW absorption mechanisms.

Rapidly synthesizing magneto-thermal adjustable high entropy alloy nanoparticles on carbon fiber surface for enhancing electromagnetic wave absorption, thermal conductivity and interface compatibility of composites

It is a significant challenge to develop a fast carbon fiber (CF) surface modification method that could generate a simple multifunctional CF surface, especially in the field of electromagnetic wave (EMW) and thermal regulation. Herein, the FeCoNiAlMn high-entropy alloy (HEA) nanoparticles modified CF (HEA-CF) was successfully prepared by microwave induced carbon thermal shock (MCTS) in a few seconds. The HEA-CF possessed magneto-thermal adjustability by controlling the elemental composition and crystal structures of HEA nanoparticles. It exhibited outstanding dielectric-magnetic loss and phonon heat transfer capability. Moreover, HEA nanoparticles and cellulose nanofibers on CF surface also formed multiscale interfacial reinforced structure. Consequently, HEA-CF/Polyamide 6 (PA6) composites demonstrated extraordinary versatility. MCTS5s-CF/PA6 exhibited the strongest absorption with minimum reflection loss value of −63.6 dB at 2.4 mm thickness. The maximum effective absorption bandwidth reached 6.67 GHz with thickness of only 1.9 mm. Compared with that of untreated-CF/PA6 composite, the thermal conductivities of MCTS4s-CF and MCTS5s-CF/PA6 composites increased by 45.2 % and 19.1 %. Simultaneously, the tensile strength of MCTS4s-CF/PA6 and MCTS5s-CF/PA6 composites increased by 19.5 % and 16.1 %. This new approach provided an effective way to realize multifunctional composites. Its low-cost, efficient and environmentally friendly process had great potential for large-scale production.

MOF derivatives anchored to multichannel hollow carbon fibers with gradient structures for corrosion resistance and efficient electromagnetic wave absorption

With the rapid development of 5G technology and the interconnection of industrial production, electromagnetic pollution has become a serious problem. Achieving lightweight and controllable loads of absorbers while obtaining corrosion-resistant absorbers with high electromagnetic response properties is still considered a huge challenge. In this work, carbon fiber with a multichannel hollow structure is obtained by PAN/PS hybrid electrospinning and subsequent high-temperature roasting process. The spatial structure inside the carbon fiber plays an active role in optimizing the impedance matching characteristics of the absorber. In addition, bimetallic metal-organic frameworks (MOFs) derivatives are obtained by a precisely controlled ion exchange as well as a high-temperature gas-phase selenization process. The resulting introduction of a non-homogeneous interface induces interfacial polarization and improves the absorption behavior of the absorber. The analysis of the experimental results shows that the electromagnetic wave (EMW) absorption performance can be effectively enhanced due to the mechanisms of interface polarization and dipole polarization. The prepared NiSe/ZnSe/MHCFs composite can obtain excellent EMW absorption properties in C, X, and Ku bands by adjusting the thickness. Structural design and component modulation play a crucial role in realizing the strong absorption and wide bandwidth of the absorber. Radar cross-section calculations indicate that NiSe/ZnSe/MHCFs have tremendous potential in practical military stealth technology. And the prepared composite coating can provide periodic corrosion resistance to Q235 steel sheet when dealing with complex and extreme environments.

Polypyrrole nanoclips-coated Co/C nanostructures with enhanced microwave absorption

There is a challenge to boost the electromagnetic wave absorption performance of magnetic carbon-based materials by rationally adjusting the structure of MOF. In this paper, nanoclip-shaped polypyrrole (PPy) was wrapped on the surface of the Co/C nanoparticle derived from Co-MOF via in-situ polymerization of pyrrole with the help of cetylammonium bromide. The electromagnetic parameters of prepared Co/C@PPy can be easily tuned by adjusting the feed ratio of PPy to Co/C. The optimum value of reflection loss (RL) for Co/C@PPy is −45.49 dB at 2.4 mm and 15.12 GHz when the feed ratio of pyrrole to Co/C is 200 μL to 80 mg, and the effective absorption bandwidth (EAB, RL ≤ −10 dB) reaches 5.97 GHz (11.76–17.73 GHz) at the matching thickness of 2.5 mm. This study paves the way for further design and preparation of the nanocomposites based on MOF-derived nanostructures with excellent EMW absorption performance.

NiCoZn/C@melamine sponge-derived carbon composites with high-performance electromagnetic wave absorption

NiCoZn/C@melamine sponge-derived carbon composites with high-performance electromagnetic wave absorption

Kirkendall Effect-Induced Ternary Heterointerfaces Engineering for High Polarization Loss MOF-LDH-MXene Absorbers.

Heterogeneous interfacial engineering has garnered widespread attention for optimizing polarization loss and enhancing the performance of electromagnetic wave absorption. A novel Kirkendall effect-assisted electrostatic self-assembly method is employed to construct a metal-organic framework (MOF, MIL-88A) decorated with Ni-Fe layered double hydroxide (LDH), forming a multilayer nano-cage coated with Ti3C2Tx. By modulating the surface adsorption of Ti3C2Tx on LDH, the heterointerfaces in MOF-LDH-MXene ternary composites exhibit excellent interfacial polarization loss. Additionally, the Ni-Fe LDH@Ti3C2Tx nano-cage exhibits a large specific surface area, abundant defects, and a large number of heterojunction structures, resulting in excellent electromagnetic wave absorption performance. The MIL-88A@Ni-Fe LDH@Ti3C2Tx-1.0 nano-cage achieves a reflection loss value of -46.7 dB at a thickness of 1.4mm and an effective absorption bandwidth of 5.12 GHz at a thickness of 1.8mm. The heterojunction interface composed of Ni-Fe LDH and Ti3C2Tx helps to enhance polarization loss. Additionally, Ti3C2Tx forms a conductive network on the surface, while the cavity between the MIL-88A core and the Ni-Fe LDH shell facilitates multiple attenuations by increasing the transmission path of internal incident waves. This work may reveal a new structural design of multi-component composites by heterointerfaces engineering for electromagnetic wave absorption.

Template-free synthesize of PANI nanostructures: Modulating structure for enhanced dielectric characteristics and superior electromagnetic wave absorption

To provide electromagnetic protection for intelligent equipment, advanced electromagnetic wave absorption (EWA) materials are highly desired. To reveal the interaction mechanism of structure and electromagnetic waves, polyaniline (PANI) with various structures, including nanosheets, clusters, and nanofibers, is synthesized via a template-free approach. The self-assembly process of PANI can be regulated by camphor sulfonic acid due to the formation and guidance of charge transfer complexes. A comprehensive analysis of structure, chemical constitution, and electromagnetic characteristics is conducted. Clusters with three-dimensional micro-nano structure exhibit superior microwave absorption, achieving a minimum reflection loss of −52.22 dB at 9.84 GHz with a 3.2 mm thickness and an absorption bandwidth of 6.12 GHz at 2.3 mm thickness. The outstanding EWA performance is attributed to the unique architecture, strong dielectric loss capabilities, and effective impedance matching. Moreover, the fabrication process is cost-effective and scalable, making it conducive to practical applicability.

Advances in Carbon Microsphere-Based Nanomaterials for Efficient Electromagnetic Wave Absorption.

Carbon microspheres have indeed shown great promise as effective materials for absorbing electromagnetic waves, particularly in microwave applications. Their unique properties, such as high surface area, porosity, and electronic characteristics, make them ideal candidates for addressing the growing concerns around electromagnetic pollution from electronic devices. By leveraging the properties of these materials, we can work toward creating more efficient and sustainable electromagnetic wave absorption technologies. Recent efforts have focused on synthesizing and investigating carbon microsphere-based electromagnetic wave-absorbing nanomaterials with the ambition of achieving the desired attributes of being thin, light, wide, and robust. This Review first delves into the detailed mechanism of electromagnetic wave absorption, followed by an elucidation of the preparation methods for carbon microsphere-based nanomaterials. Furthermore, it systematically outlines the common methods and strategies employed to improve the microwave absorption capabilities of carbon microspheres, including chemical vapor deposition, emulsion polymerization, hydrothermal methods, and template methods. Lastly, it outlines the challenges encountered by carbon microsphere-based electromagnetic wave absorption nanomaterials and outlines their prospects, mainly morphology change, component hybridization, and elemental doping. This Review aims to provide valuable insights into the creation of carbon microsphere nanomaterials with excellent electromagnetic wave absorption properties.

Synchronously Formed Hetero- and Hollow Core-Branch Nanostructure Toward Wideband Electromagnetic Wave Absorption.

The intrinsic limitation of low electrical conductivity of MoSe2 resulted in inferior dielectric properties, which restricts its electromagnetic wave absorption (EMWA) performances. Herein, a bimetallic selenide of MoSe2/CoSe2@N-doped carbon (NC) composites with hollow core-branch nanostructures are synthesized via the selenization treatment of MoO3 nanorods coated with ZIF-67. By adjusting the mass ratio of ZIF-67 to MoO3, the electromagnetic parameters and morphologies of composites are finely tuned, further ameliorating the impedance matching and EMWA performances. The involvement of NC improves the electronic conductivity of the composites. The synchronously formed heterostructure not only facilitates charge transfer but also leads to the accumulation and uneven distribution of charges, thus enhancing the conductive loss and polarization loss. The hollow core-branch nanostructure provides abundant conductive networks, heterointerfaces, and voids, significantly enhancing the EMWA property. Density functional theory implies that the heterostructures effectively boost charge transport and change charge distribution, which heightens the conductive loss and polarization loss. As a result, the composites demonstrate a minimum reflection loss value of -53.53 dB at 9.04 GHz, alongside a maximum effective absorption bandwidth of 6.32 GHz. This work offers invaluable insights into novel structural designs for future research and applications.

Air-microwave simultaneously induced carbon fiber surface oxidation and magnetism adjustment by CoOx nanoparticles rapid assembly for interface enhancement and electromagnetic wave absorption of its composites

It is a significant challenge to develop a fast carbon fiber (CF) surface modification method, especially for the high strength electromagnetic wave (EMW) absorption materials. Herein, magnetic CoOx nanoparticles are successfully synthesized and uniformly assembled on CF surface with high oxygen-containing groups by rapid ambient microwave carbon thermal shock (MCTS). The presence of oxygen defect sites on CF surface promotes CoOx nanoparticles nucleation. The number of oxygen defects and the types of magnetic nanoparticles on the CF surface effectively adjust the surface chemical activity and the electromagnetic properties of CF, which is conducive to improving the EMW absorption performance and interface compatibility of the CoOx nanoparticles modified CF reinforced polyamide 6 (CO@CF/PA6) composites. Compared with CO@CF-0 s/PA6, the tensile strength and modulus of CO@CF-3.5 s/PA6 composite are increased by 18.1 % and 18.6 %, respectively. It also displays a minimum reflection loss value (−59.9 dB) at a thinner thickness of 1.9 mm while the maximum effective absorption bandwidth reaches 5.02 GHz with a thickness of 1.8 mm. Its radar cross-section values exhibit less than −10 dBm2 at all tested detection angles. This rapid MCTS shows great potential for large-scale production of CF modification with low-cost, efficient and environmentally friendly process.

Wideband water-based switchable metasurface absorber/reflector

A water-based switchable absorber/reflector (WSAR) based on toner-coated honeycomb is proposed. The structure consists of a metasurface absorbing layer, a toner honeycomb layer, a water layer and a metal plate. The combination of metasurface and coated toner honeycomb can realize the function of broadband absorption, and the water layer is used as a control purpose to obtain a good reflection effect by filling the container with water. When the water container is in the state of without water, it behaves as an electromagnetic wave absorber with good absorption performance in the frequency band of 4.72–17.50 GHz. When the water container is in the state of full water，it behaves as a reflector with good reflection performance (reflection coefficient close to −1 dB in the 4.5–10 GHz band) in the operating frequency band. The characteristics and mechanism of the WSAR are analyzed by using the energy loss and equivalent impedance matching, and the correctness of the design is verified by experiments. The proposed structure has certain application value in radar target stealth, electromagnetic compatibility, adaptive camouflage.