High-performance Electromagnetic Wave Absorption Research Articles

Surface modification by CO2 plasma boosting core shells structural Fe/Fe3C/FeN @ graphite carbon nanoparticles toward high performance microwave absorber

The surface modification of three-dimensional (3D) materials is an efficient method for adjusting their interfacial defect concentration, electronic conductivity and content of functional groups with extensive applications in catalysis, electrode materials and bioengineering. In this work, a multiphase iron nanocrystals consisting of Fe3C, Fe and FeN nanoparticles encapsulated in hierarchical structure of graphite carbon (denoted as Fe/Fe3C/FeN@GC) is synthesized for the first time by a novel high temperature plasma method. Meanwhile, more defects and functional groups are introduced by surface modification of graphite carbon layer of Fe/Fe3C/FeN@GC with controllable CO2 (low temperature) plasma. Benefiting from the advantages of multiple heterogenous interface and the abundant interfacial polarization relaxation that represent strong electromagnetic (EM) wave dissipation as well as an applicable impedance matching, the optimized Fe/Fe3C/FeN@GC demonstrate superior microwave absorption (MA) properties. The minimum reflection loss (RL) achieves −54.4 dB (more than 99.9% MA) at 17.6 GHz with a thin thickness of 1.8 mm, and the maximum effective absorption bandwidth (EAB, RL < −10 dB) is up to 6.2 GHz (11.8–18.0 GHz) at 2.0 mm. The above results reveal that the optimized Fe/Fe3C/FeN@GC composites with strong absorption, broad EAB, light mass (only filling content of 30 wt%) and ultrathin thickness are prospective candidate for high performance EM wave absorbers.

Synthesis and characterization of high-performance electromagnetic wave absorption of CoS/Co9S8/WS2 composites

Synthesis and characterization of high-performance electromagnetic wave absorption of CoS/Co9S8/WS2 composites

Carbon nanofibers embedded with Fe–Co alloy nanoparticles via electrospinning as lightweight high-performance electromagnetic wave absorbers

Carbon nanofibers embedded with Fe–Co alloy nanoparticles via electrospinning as lightweight high-performance electromagnetic wave absorbers

Fabrication of hollow Ni/NiO/C/MnO2@polypyrrole core-shell structures for high-performance electromagnetic wave absorption

In response to the increasingly serious problem of electromagnetic wave pollution, there is a growing demand for materials capable of absorbing electromagnetic waves. A crucial strategy involves optimizing the microstructure and composition of these materials. In this study, the Ni/NiO/C/MnO2@PPy (NCMP) composites are successfully fabricated through the combination of hydrothermal method, high-temperature calcination process, chemical method and in situ polymerization. Due to the strong synergistic effect of the dielectric and magnetic components, and good impedance match, the NCMP-40 exhibits excellent electromagnetic wave absorption properties, with an optimal reflection loss (RLmin) of −56.23 dB at a thickness of 3.87 mm, and a high effective absorption bandwidth (EAB) of 6.86 GHz (10.68–17.54 GHz) at a thickness of 1.97 mm covering the entire Ku-band part of the X-band. Moreover, the radar cross section (RCS) attenuation is obtained through a simulation procedure. Compared to the sole perfect electrically conductive (PEC) layer, the PEC layer coated with NCMP-40 achieves an RCS value consistently below −10 dB m2 in the range of −60° < θ < 60°, and an RCS value is −22.0 dB m2 at θ = 0°. The prepared NCMP-40 presented herein shows excellent electromagnetic wave absorption performances. And this study provides a new method for the structural design of electromagnetic wave absorption materials.

Regulating the carbon shell structure of hollow cubic carbon for high performance electromagnetic wave absorption

Herein, HCCs absorbers were synthesized by pyrolysis of phenolic resin, which was uniformly spread onto the surface of NaCl crystals. An investigation was undertaken to assess the effect of shell thickness on wave-absorbing capacity by altering the timing of the phenolic resin reaction. The morphology, composition and electromagnetic properties of the samples were also analyzed for different reaction times. Scanning electron microscopy (SEM) findings revealed a progressive increase in shell thickness of the HCCs from 28.728 nm to 92.654 nm, accompanied by a gradual enlargement in sample size. Compared to samples obtained at other reaction times, the sample reacted for 48 h exhibited favorable wave absorption properties attributed to its fitting shell thickness and impedance matching. Specifically, at a load rate of 5 wt% and the thickness of 2.7 mm, the maximum reflection loss reaches −50.5 dB with an effective absorption bandwidth of 6.2 GHz (11.8 GHz–18.0 GHz). Thus by altering the synthesis duration of phenolic resin is possible to effectively adjust the carbon shell morphology, thereby enhancing the capability for electromagnetic wave absorption.

Construction of Hierarchical Yolk-Shell Co/N-Dope C@void@C@MoS2 Composites with Multiple Heterogeneous Interfaces toward Broadband Electromagnetic Wave Absorption.

The synthesis of materials with a multicomponent hierarchical structure is an essential strategy for achieving high-performance electromagnetic wave (EMW) absorption. However, conventional design strategies face challenges in terms of the rational construction of specific architecture. In this study, we employ a combined space-restricted and hierarchical construction strategy to surface-plant MoS2 nanosheets on yolk-shell structural carbon-modified Co-based composites, leading to the development of high-performance Co/NC@void@C@MoS2 absorbers with advanced architecture. The surface-planted MoS2 nanosheets, the Co/NC magnetic yolk, and the dielectric carbon shell work together to enhance the impedance matching characteristics and synergistic loss capabilities in the composites. Experimental results indicate that Co/NC@void@C-700@MoS2 exhibited the best absorption performance with an effective absorption bandwidth of 7.54 GHz (at 2.05 mm) and a minimum reflection loss of -60.88 dB (at 1.85 mm). Furthermore, radar cross-section simulation results demonstrate that Co/NC@void@C-700@MoS2 effectively suppresses the scattering and transmission of EMWs on perfect electric conductor substrates, implying its superior practical application value. This study provides inspiration and experimental basis for designing and optimizing EMW absorption materials with hierarchical yolk-shell architecture.

MOF Derivatives with Gradient Structure Anchored on Carbon Foam for High-Performance Electromagnetic Wave Absorption.

The impedance matching and high loss capabilities of composites with homogeneous distribution are limited owing to high addition and lack of structural design. Developing composites with heterogeneous distribution can achieve strong and wide electromagnetic (EM) wave absorption. However, challenges such as complex design and unclear absorption mechanisms still exist. Herein, a novel composite with a heterogeneous distribution gradient is successfully constructed via MOF derivatives Co@ nitrogen-doped carbon (Co@NC) anchored on carbon foam (CF) matrix (MDCF). Notably, the concentration of MOF can easily control the gradient structure. In particular, the morphologies of MOF derivatives on the surface of CF undergo a transition from the collapse of the inner layer to the integrity of the outer layer, accompanied by a continuous reduction in the size of Co nanoparticles. Correspondingly, enhanced interface polarization from the core-shell of Co@NC and good impedance matching of MDCF can be obtained. The optimized MDCF exhibits the minimum reflection loss of -68.18dB at 2.01mm and effective absorption bandwidth covering the entire X-band. Moreover, MDCF exhibits lightweight characteristics, excellent compressive strength, and low radar cross-section reduction. This work highlights the immense potential of composites with heterogeneous distribution for achieving high-performance EM wave absorption.

Rose-Derived Porous Carbon and In-Situ Fabrication of Cobalt/Nickel Nanoparticles Composites as High-Performance Electromagnetic Wave Absorber

Rose-Derived Porous Carbon and In-Situ Fabrication of Cobalt/Nickel Nanoparticles Composites as High-Performance Electromagnetic Wave Absorber

In situ fabrication of Fe3C nanoparticles and porous-carbon composites as high-performance electromagnetic wave absorber.

This study successfully utilized a straightforward approach, choosing liquid-liquid phase separation to build a porous structure and synthesize composite absorbers based on polyimide-based porous carbon/Fe3C (PIC/Fe3C-1, PIC/Fe3C-2) nanoparticles and porous carbon/FeCo alloy nanoparticles (PIC/FeCo). The specially designed network structure pore structures contributed multiple reflection, conduction loss and strong interfacial polarization. After characterization, PIC/Fe3C-2 obtained minimum RL of -35.37 dB at 17.04 GHz with 1.55 mm thickness and effective absorption bandwidth of 4.95 GHz with 1.66 mm thickness. Furthermore, PIC/FeCo, with a thickness of 1.63 mm, exhibits the most robust electromagnetic wave loss ability at 15.6 GHz, with a minimum RL of -56.32 dB and an effective absorption bandwidth of 4.88 GHz. Thus, the design strategy presented in this study could serve as a model for synthesizing other high-performance absorbers, effectively mitigating electromagnetic wave-induced pollution.

Polyimide-based porous carbon and cobalt nanoparticle composites as high-performance electromagnetic wave absorbers.

This study successfully utilized a straightforward approach, choosing liquid-liquid phase separation to build a porous structure and synthesize composite absorbers based on polyimide-based porous carbon and cobalt nanoparticles (designated as PPC/Co-700 and PPC/Co-800). A fine porous structure was achieved as a result of the excellent heat resistance of polyimide resulting in an excellent electromagnetic wave absorption ability of PPC/Co composites. The results obtained clearly indicated that PPC/Co-700 and PPC/Co-800 exhibit a porous structure with coral-like pores, enhancing both impedance matching properties and microwave attenuation abilities. This improvement in impedance matching conditions and dissipation capability is attributed to the synergistic effect of dielectric loss induced by carbon and magnetic loss induced by Co nanoparticles. PPC/Co-700 showed the strongest absorption performance with a minimum reflection loss of -59.85 dB (30 wt% loading, thickness of 3.42 mm) and an effective absorption bandwidth (EABW, RL ≤ -10 dB) of 6.24 GHz (30 wt% loading, thickness of 2.78 mm). Therefore, this work provides a facile strategy for the development of a promising absorbing material with outstanding electromagnetic wave absorption performance.

High-performance electromagnetic wave absorption in FeS2/SnS2@multi-walled carbon nanotube composites with honeycomb-shaped structure.

In this work, we synthesized composites of ferrous disulfide and tin disulfide with multi-walled carbon nanotubes (MWCNTs) using a straightforward hydrothermal method. The incorporation of carbon nanotubes significantly enhanced the dielectric loss capability of the composites. When the filling ratio of FeS2/SnS2@CNTs (20 wt%) in paraffin was 40%, the effective absorption bandwidth was 3.28 GHz, while the minimum reflection loss (RL) value was as high as -39.2 dB, which corresponded to a thickness of only 1.4 mm. This work reveals the potential research value of this material in terms of thin thickness, strong absorption and light mass.

Construction of urchin-like porous Co/CoO/C composites enabling high-performance wideband electromagnetic wave absorption

A series of urchin-like porous Co/CoO/C composites with wideband and strong EWA performance have been prepared, in which the 3D porous urchin-like microstructures facilitate the propagation and attenuation of electromagnetic waves.

Controllable fabrication of CoNi bimetallic alloy for high-performance electromagnetic wave absorption.

With the coming era of artificial intelligence (AI) dominated by high-tech electronics, developing high-performance microwave absorption materials (MAMs) is imperative to solve the problem of increasing electromagnetic inference and pollution. Herein, a metal-organic framework (MOF)-derived CoNi bimetallic alloy (CoNi/C) with an irregular rod-like structure is prepared by a thermal reduction method. Introducing the CoNi alloy facilitates the balance between conduction loss and polarization loss and forms good impedance matching, leading to excellent microwave absorption performance. Interestingly, the optimization of absorption performance can be further achieved by controllably modulating the molar ratio of Co and Ni (Co2+/Ni2+). As expected, the obtained CoNi/C delivers excellent microwave absorption performance with a minimum reflection loss (RLmin) of -50.80 dB at 10.40 GHz and an effective absorption bandwidth (EAB) of 3.28 GHz (8.91-12.19 GHz) with a filler loading of 50 wt% at 2.0 mm. In addition, the CoNi/C can reach a maximum EAB of 4.77 GHz (12.99-17.76 GHz) at a low thickness of 1.5 mm, spanning nearly the entire Ku band. The CoNi3/C also exhibits an impressive RLmin of -44.84 dB at 3.28 GHz in the S band. This work offers a novel strategy to modulate the magnetic/electric properties of MOF-derived MAMs.

An equivalent RLC circuit loss mechanism introduced by Fe2O3 nanoneedle arrays towards high-performance electromagnetic wave absorption materials

The introduction of an equivalent RLC circuit loss mechanism realizes strong EMW absorption in a low-filling ratio and even lower thicknesses.

A dilute ferromagnetic ZrO2/carbon nanocomposite derived from a zirconium-based metal–organic framework for high-performance electromagnetic wave absorption

Dilute ferromagnetic ZrO2/carbon nanocomposites have been fabricated based on a Zr-MOF. The ZrO2/C_700 nanocomposite exhibits a superior reflection loss of −59.69 dB at 2.88 mm and a wide effective absorption bandwidth of 6.44 GHz at 2.36 mm.

Regulating the vacancies of nitrogen-doped carbon nanohorns for high-performance electromagnetic wave absorption.

Single-walled carbon nanohorns (SWCNHs), which are sealed on one side with a conical cap and can self-aggregate, are aggregates with spherical morphology ranging from 30 to 100 nm and include dahlia, bud, and seed structures. These SWCNHs are suitable for electromagnetic wave absorption (EMWA) due to their conductivity loss. However, conductivity loss, which is part of three primary loss mechanisms, leads to SWCNHs suffering from impedance mismatching and a narrow effective absorption bandwidth (EAB). In this work, the content of vacancy-type defects in "dahlia-like" nitrogen-doped single-walled carbon nanohorns (NSWCNHs) is regulated by dielectric barrier discharge (DBD) plasma with argon to adjust their polarization and impedance matching. The high-energy argon ions from the plasma impact the bonds between the carbon atoms and adsorbed oxygen, leading to the sputtering of oxygen atoms from the surface and resulting in an increase in surface disorder and defect content. Vacancy-type defects improved polarization loss and optimized impedance matching, leading to the satisfactory EMWA performance of NSWCNHs. The NSWCNHs exhibit an outstanding minimum reflection loss (RLmin) of -57.94 dB when subjected to argon DBD treatment for 5 minutes, achieving this remarkable result at a thickness of 1.9 mm. Additionally, the effective absorption bandwidth (EAB) can cover 4.78 GHz after a treatment period of 1 minute. These results suggest that NSWCNHs have great potential as high-efficiency EMWA materials and demonstrate a new approach for designing high-performance EMWA absorbers.

Facile fabrication of NiFe2O4-FeNi/C heterointerface composites with balanced magnetic-dielectric loss for boosting electromagnetic wave absorption

In the electronic information age, and even in the impending “intelligent era”, electromagnetic wave (EMW) absorbers have inevitably received more and more attention. However, their practical applications are currently limited by a lack of suitable mass-production strategies for high performance EMW absorbers. Herein, we propose a facile strategy for large-scale and controllable preparation of NiFe2O4-FeNi/C (NFO-FN/C) composites with various microstructural features advantageous to enhanced EMW absorption, including core-shell structure, porous structure, hierarchical nano-micro topography, and electromagnetic heterointerfaces. The composites are synthesized through the confinement pyrolysis of the polydopamine (PDA)-coated NiFe2O4 (NFO), and their microstructural features can be facilely tailored by changing the number of PDA confinement. The synthesized composite of NFO-FN/C-2 performs best after two repetitions of PDA confinement throughout the preparation process, with a reflection loss (RLmin) of −68.74 dB at a thickness of 1.61 mm and a broad effective absorption of 6.37 GHz at a thickness of 1.9 mm. This impressive EMW absorption performance is attributed to the synergistic effect of multiple loss mechanisms and excellent impedance matching derived from the tailored microstructural features of our EMW absorbers. This work provides a new perspective on the large-scale preparation of highly efficient EMW absorbing materials.

Synthesis of SiC nanowires wrapped in trimetallic layered double hydroxide nanosheets with core-shell structure via self-assembly growth approach for effective electromagnetic wave absorption

The optimization of microstructure and composition is an important strategy to obtain high-performance electromagnetic wave absorption (EMA) materials. In this study, several fungus-like two-dimensional (2D) trimetallic layered double hydroxide (LDH) nanosheets have been synthesized with tunable metallic ions of Ni2+, Co2+, and Zn2+ by using a compositional genetic strategy from MOF. Thereafter, a series of core-shell composites have been fabricated at room temperature by the self-assembly growth approach, constructed from 2D trimetallic LDH nanosheets wrapped on 1D SiC nanowires. The composition and structure of the samples can be preserved by varying the Co and Zn ratios. The EMA materials were prepared by performing a thermal treatment approach in the air atmosphere based on the synthesized composites described above. A reasonable integration of dielectric and magnetic components and an opportune core-shell structure provide better impedance matching, multiple reflections and scattering, polarization loss, enhancing conduction loss, and magnetic loss. The results show that NiCo2Zn1-LC@SiC exhibits superior EMA performance with the minimum reflection loss (RLmin) of −44.73 dB at a thickness of 1.86 mm and the maximum effective absorption band (EABmax) of 6.12 GHz at 2.12 mm. This work proves the influence of the structure and composition on absorbers and provides ideas for the design and development of high-performance EMA materials in a facile approach.

Multi-scale heterostructures of MXene-based composites for adjustable electromagnetic wave absorption

Nowadays, electromagnetic pollution caused by the development of communication technology and electronic equipment has become an urgent problem to be solved. It is an effective solution to design high-performance electromagnetic wave absorption (EWA) materials with wide-band and powerful absorption characteristics for electromagnetic protection. In this work, a multi-scale MXene/carbon nanotube@Fe3O4 composite material with a heterogeneous structure was synthesized by a solvothermal method, and the high/low-frequency EWA operating bands were adjusted by component regulation. The composite material performed excellent EWA performances based on the synergistic effect of polarization loss, conductive and magnetic loss, and three-dimensional heterointerfaces. Its minimum reflection loss reached − 59.95 dB with an effective absorption bandwidth of 4.7 GHz (13.3–18 GHz), which basically covered the Ku band. Therefore, this feasible scheme is expected to provide an effective strategy for controlling military and civil electromagnetic pollution.

Controllable heterogeneous interfaces and dielectric modulation of biomass-derived nanosheet metal-sulfide complexes for high-performance electromagnetic wave absorption

Constructing new environmentally friendly dielectric coupling models is an effective strategy for designing high-performance wave absorbers. However, biomass carbon materials with high potential energy and a lack of magnetic response mechanism do not fulfill the requirements. In this work, the effects of different pyrolysis temperatures and the introduction of different metal sulfides on the microscopic morphology and dielectric-magnetic properties of the composites were investigated. Among them, K element detected in the biomass effectively modulates the conduction loss. The minimum reflection loss (RLmin) of –62.42 dB at 1.8 mm and the maximum effective absorption bandwidth (EABmax) of –62.42 dB at 1.9 mm were obtained due to the non-uniform interfacial-induced polarization of the metal-sulfide nanosheets and the scattering of the electromagnetic waves (EW) by the “island” microstructures. This study provides a powerful reference for the modification and application of biomass materials.