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With the accelerating development of electronic technology, how to effectively eliminate electromagnetic radiation pollution has become a critical issue. Electromagnetic wave (EMW) absorption materials have an irreplaceable position in the field of military stealth as well as in the field of electromagnetic pollution control. In order to cope with the complicated electromagnetic environment, the design of multifunctional and multiband high-efficiency EMW absorbers remains a daunting challenge. In this work, a hierarchical porous molybdenum carbide matrix with a three-dimensional porous structure was designed by salt melt synthesis (SMS) strategy. Furthermore, the relationship between the structure and the impedance matching performance was explored by stepwise modification via ultrathin layered MoS2 nanoflakes. Analysis indicates that the extent of modification of hierarchical porous molybdenum carbide by MoS2 nanoflakes modulates the dielectric performance due to differences in morphology and the introduction of heterogeneous structures, along with a dramatic impact on the impedance matching performance. In particular, the prepared MS/MC/PNC-2 composite exhibits a reflection loss (RL) of -55.30 dB at 2.4 mm, and an ultra-broad effective absorption bandwidth (EAB) of 7.60 GHz is obtained at 2.0 mm. The coordination of structure and component enables the absorber to exhibit strong absorption, wide bandwidth, thin thickness, and multi-band absorption characteristics. Noticeably, the effective absorption performance in the broadband for X and Ku is also satisfying, as well as possessing moderate marine anti-corrosion performance. This study contributes to an in-depth understanding of the relationship between impedance matching and EMW absorber performance and provides a reference for the design of multifunctional, multiband microwave absorbing materials. [ABSTRACT FROM AUTHOR]

As the integration technology for integrated circuit (IC) packaging continues to advance, the issue of electromagnetic interference in IC packaging becomes increasingly prominent. Magnetic materials, acknowledged for their superior electromagnetic absorption capabilities, play a pivotal role in mitigating electromagnetic interference problems. In this study, we employed a liquid-phase reduction method. We prepared three types of cobalt (Co) particles with distinct morphologies. Through variations in the synthesis process conditions, we were able to control the aspect ratio of protrusions on the surface of the Co particles. It was found that the sword-like Co particles exhibit superior electromagnetic wave absorption capabilities, showing a reflection loss value of up to −50.96 dB. Notably, when the coating thickness is only 1.6 mm, the effective absorption bandwidth is extended up to 7.6 GHz. The spatially expansive sword-like Co particles, with their unique structure featuring dipole polarization and interfacial polarization, demonstrated enhanced dielectric and magnetic loss capabilities, concurrently showcasing superior impedance-matching performance. [ABSTRACT FROM AUTHOR]

Atomic‐level structural editing is a promising way for facile synthesis and accurately constructing dielectric/magnetic synergistic attenuated hetero‐units in electromagnetic wave absorbers (EWAs), but it is hard to realize. Herein, utilizing the rapid explosive volume expansion of the CoFe‐bimetallic energetic metallic triazole framework (CoFe@E‐MTF) during the heat treatment, the effective absorption bandwidth and the maximum absorption intensity of a series of atomic CoFe‐inserted hierarchical porous carbon (CoFe@HPC) EWAs can be modified under the diverse synthetic temperature. Under the filler loading of 15 wt%, the fully covered X and Ku bands at 3 and 2.5 mm for CoFe@HPC800 and the superb minimum reflection loss (RLmin) of −53.15 dB and specific reflection loss (SRL) of −101.24 dB mg−1 mm−1 for CoFe@HPC1000 are achieved. More importantly, the single‐atomic chemical bonding among Co─Fe on the nanopores is captured by extended X‐ray absorption fine structure, which reveals the formation mechanism of nanopore‐confined vortical dipoles and magnetic domains. This work heralds the infinite possibilities of atomic editing EWA in the future. [ABSTRACT FROM AUTHOR]

Ferrites were among the earliest types of microwave absorbers due to their high magnetic dissipation and low cost. Ferrites, on the other hand, have some disadvantages, such as a low natural resonance frequency (fr), a lack of dielectric loss, and a high density. We effectively generated (SrMnCoFe 10 O 19 /MnCoFe 2 O 4)/SiO 2 samples with hollow microfiber morphologies and most of the effective parameters suggested to overcome these disadvantages and increase the microwave dissipation properties of ferrites. Hard and soft SrMnCoFe 10 O 19 /MnCoFe 2 O 4 hollow microfibers were obtained using sol-gel and electrospinning technology. After heat treatment at 1050 °C for 3 h, the binary ferrites are formed. (Hard ferrite/soft ferrite)/SiO 2 core-shell structures were fabricated by the Stober process, so their microwave absorption performance is greatly influenced by the hard/soft mass ratio and SiO 2 thickness of the sample. The fabricated fibers were characterized by x-ray diffraction (XRD), vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FESEM), FTIR spectroscopy, and vector network analyzer (VNA). The single-phase structure of all microfibers was determined by X-ray diffraction (XRD) analysis. The phase formation of the coated microfibers is also elaborated using Fourier transform infrared spectroscopy (FTIR) based on identified chemical bonds. According to the (FESEM) analysis results, the microfibers manufactured have a homogeneous core–shell structure. A vector network analyzer was used to investigate the samples' dielectric constants and microwave absorption properties between 12 and 18 GHz at room temperature. The results showed that when the mass ratio is hard/soft (8: 2) and the mass ratio of ferrite/SiO 2 (1:1), the maximum reflectance loss is −27 dB and the absorption bandwidth is 2 GHz. The magnetic saturation (Ms) was calculated at 43.44 emu/g and the calculated coercivity values (1163.07 Oe) confirm the hard ferrite/soft ferrite/SiO 2 core-shell structures. [Display omitted] [ABSTRACT FROM AUTHOR]

In this research, we developed a wideband electromagnetic wave absorber suitable for the X-band frequency by using a unique hybrid nanocomposite structure made of FeWO 4 embellished with Ag 3 PO 4 nanopowders. Simple chemical hydrothermal and microwave-aided hydrothermal procedures were used to successfully produce single-phase spherical-like FeWO4 and FeWO4@Ag3PO4 nanocomposite powders. Using XRD, FTIR, VSM, FESEM, and VNA methods, the phase constituents, morphological, magnetic, and electromagnetic properties of the produced nanocomposite materials were assessed. The resin-based nanocomposite absorber sample allows to obtain a maximum reflection loss of −21 dB with a matching thickness of 1.8 mm at the ferromagnetic resonance of 10.4 GHz with a 3.8 GHz effective absorption bandwidth, which is evaluated using the waveguide technique, when the filler loading percentage reaches 40 wt percent (S40). S40 had superior impedance matching capabilities, a wide effective absorption bandwidth, and a high absorption capacity when compared to other produced absorber samples. The best sample is prepared for free-space testing with the dimension of 200 × 200 mm and an optimum thickness of 1.8 mm, and the results demonstrate a good agreement between the waveguide and free-space technique results. This absorber sample's wideband absorption capacity was attained by adjusting the magneto-electric composition and enhancing the interfacial characteristics brought on by the core-shell construction. In this study, a design approach for efficient microwave absorbers based on a magneto-electric hybrid nanocomposite structure is presented, using waveguide and free-space experimental methods in two different ways. [ABSTRACT FROM AUTHOR]

In this study, the electromagnetic wave absorption properties of woven glass fiber reinforced epoxy composites with Sb2O3 and SnO2 nanoparticles doped mica pigments were investigated. Herein, we synthesized SnO2/mica, Sb2O3/mica, and Sb2O3:SnO2/mica pigments using the sol–gel method. Subsequently, mica pigments filled glass fiber/epoxy composite panels were fabricated with a vacuum assisted resin mold. The phase, crystal, and morphological examinations of particles confirm the deposition of SnO2 and Sb2O3 nanoparticles on the mica surfaces. The electromagnetic wave absorption properties of samples were measured using the S parameters and obtained dielectric data. Sb2O3:SnO2/mica particles display higher complex permittivity and dielectric loss values due to the strong interfacial polarization between conductive nano metal‐oxide shells and mica surfaces. According to the calculated reflection loss values, Sb2O3:SnO2/mica particles exhibit superior electromagnetic wave absorption performance with a minimum reflection loss of −25.62 dB for 2.4 mm thicknesses with effective bandwidth between 9.3 and 12.4 GHz. The S parameters of the prepared structural composites with the size of 30 cm × 30 cm × 3 mm was determined by the free‐space technique using the transmission line technique. According to the S12 parameters, filled glass fiber/epoxy composite containing 25 wt% Sb2O3:SnO2/mica show a minimum reflection loss of −20.426 dB at 8.2 GHz with effective bandwidth between 8.2 and 9.67 GHz. These results indicate that Sb2O3:SnO2/mica‐filled fiber/epoxy composite is an excellent candidate for the practical application of electromagnetic wave absorbers. [ABSTRACT FROM AUTHOR]

Multiple relaxation behaviors are promising for broad frequency band and strong electromagnetic wave (EMW) absorption based on polarization‐controlled electromagnetic (EM) attenuation. However, rational selection of materials and structure manipulation through tunable substitution or phase control are challenging toward optimization of EMW absorption. Herein, bi‐metallic organic frameworks (B‐MOFs) with various morphologies are employed as EMW absorbers. Remarkably, the polar units can be enhanced by introducing Ni‐metal nodes into the Cu‐coordinated MOFs, rendering the B‐MOFs with self‐polarized properties and consecutive multifrequency EMW absorption behaviors. The maximum reflection loss of acetylene black (ACET) filled NiCu‐MOFs can reach –40.54 dB together with a wide bandwidth (<‐10 dB) of 5.87 GHz at a thickness of 2.5 mm. As a counterpart of the Ni/Cu/C derivatives, significantly increased broad band absorption (6.93 GHz) and multifrequency absorbing and polarization characteristics are also maintained in bimetal coexisting carbonized architectures as prepared by calcination of CuNi‐MOFs. This work demonstrates that the performance of effective absorbing frequency band can be enhanced in multi‐metallic organic frameworks‐based architectures, and paves a novel avenue for developing broadband and strong EMW absorbers. [ABSTRACT FROM AUTHOR]

In order to overcome the problems caused by electromagnetic pollution, the design and development of high-performance microwave absorbers is urgently required. In this work, a hierarchical ZnFe 2 O 4 @MnO 2 @RGO composite was successfully fabricated via a facile and rapid hydrothermal method. Its unique core-shell structure and synergistic effect between multiple components are beneficial for electromagnetic wave absorption. The morphology, elemental composition, microstructure and microwave absorption characteristics were systematically studied. With a filler loading of 20 wt%, the composite presents a minimum reflection loss (R Lmin) of −46.7 dB and an effective absorption bandwidth (EAB) as wide as 5.2 GHz at a thickness of 2.5 mm. The superior absorption ability profits from a special microstructure, good impedance matching, multiple attenuation features, interfacial polarization, and the synergistic effect of dielectric and magnetic loss. Consequently, this work lays a foundation for the design of high-performance electromagnetic wave absorbers with multicomponent heterogeneous structures. [ABSTRACT FROM AUTHOR]

VB‐Group transition metal disulfides (TMDs) are considered excellent materials for electromagnetic wave (EMW) absorption because of their good conductivity and abundant active sites located at their edges and substrates, as compared with VIB‐Group TMDs. Herein, for the first time, EMW absorbers based on VB‐Group NbS2 nanosheets by using a facile one‐step solvothermal method are successfully prepared. The minimum reflection loss (RLmin) can reach up to 43.85 dB with an effective absorption bandwidth of 6.48 GHz (11.52–18.00 GHz). The remarkable EMW absorption performance can also be reflected in the tunable frequency bands (C‐, X‐, and Ku‐bands), which is achieved by adjusting the contents of materials. Furthermore, the influence of the content of 2H‐phase and 1T‐phase in NbS2 on the EMW absorption performance is systematically investigated. The hierarchical hollow‐sphere structure of NbS2 promotes dielectric loss and the multiple reflection and absorption of EMW, and enhances the impedance matching and synergistic attenuation ability. This work demonstrates that the bottleneck of effective absorbing frequency band of single‐component dielectric EMW absorbing materials could be broken through, and paves a novel path towards developing broadband absorbing materials in EMW absorption. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) carbon-based materials have attracted growing attention in the field of electromagnetic wave absorption applications. However, their high conductivity results in high dielectric constant, leading to impedance mismatching, and this characteristic finally weakens their electromagnetic wave absorption performance. In this work, 3D carbon foam (3DCF) was successfully prepared by calcining the melamine foam as the carbon framework precursor under N 2 atmosphere. Subsequently, 1T-2H MoS 2 nanosheets were uniformly assembled on the surface of the 3DCF skeleton through a solvothermal process. The diameter of the 3DCF skeleton was about 1 μm and the thickness of the 1T-2H MoS 2 on the surface was about 150 nm. The 3D network brings in many advantages for microwave attenuation, including numerous conductive pathways, excellent impedance matching and multi-polarization processes. The composites exhibited a maximum reflection loss (RL max) of −45.88 dB at 10.2 GHz with the thickness of 2.2 mm, and the effective absorbing bandwidth (E AB) was as wide as 5.68 GHz, implying their superb microwave absorption behavior. This work is believed to offer a strategy for the design of efficient 3D electromagnetic wave absorbers with low density in the future. [ABSTRACT FROM AUTHOR]

• Composite was prepared by coordinate combination to improve the agglomeration phenomenon. • The impedance matching of composites was optimized by constructing mesoporous structures and regularized surface structures. • The absorption mechanism of the composite was explained by analyzing electromagnetic parameters and microscopic morphology. • The reflection loss and effective absorption bandwidth of the composites are −48.5 dB and 4.52 GHz, respectively. Biomass carbon has been widely studied as an electromagnetic wave-absorbing material in recent years due to its wide range of material sources, natural porous structure, and other advantages. Herein, a series of magnetic lignin-based carbon composites have been prepared as electromagnetic wave absorbers using carboxylation lignin as an organic ligand and Fe, Co as a metal ion. The bimetallic to coordinate combination with carboxylation lignin improved the agglomeration phenomenon, optimized mesoporous structure, and the pore distribution of the material compared to monometallic. This lignin-based FeCo@C had an abundant interfacial, mesoporous structure, dielectric, and magnetic loss capability. When the ratio of Fe and Co was 1:1, the reflection loss value of −48.5 dB at 12.3 GHz, and the effective absorption bandwidth achieved 4.52 GHz with a thickness of 2.5 mm. In short, this work provided a new direction for the preparation of renewable and high-performance lignin-based electromagnetic wave absorber materials. [ABSTRACT FROM AUTHOR]

Associated with the unique structure and superior properties of zeolitic imidazolate frameworks (ZIFs) of Co-based metal-organic frameworks (MOFs), we synthesized the MWCNTs@carbonaceous CoO composites of a 3D interconnected network using multi-walled carbon nanotubes (MWCNTs) as decoration through the wet chemical and pyrolysis method. Due to the mutual coordination between proper magnetic loss and strong dielectric loss together with perfect impedance match, the MWCNTs@carbonaceous CoO composites exhibit the maximal reflection loss (RL) value of −50.2 dB with 1.84 mm thickness at 14.3 GHz, absorbing bandwidth (RL ≤ −10 dB) of 13.2 GHz (4.8–18 GHz) with respect to 1.0–4.0 mm thickness range. More importantly, the content of composites added to paraffin matrix is merely 10 wt%. In addition, the synergistic effect between CoO NPs and MWCNTs is also beneficial to the highly efficient electromagnetic (EM) wave absorption of the composites. Therefore, the obtained CoO NPs/MOF-derived composites with lightweight and thin performance can be an attractive candidate of the EM wave absorptive materials. Unlabelled Image • MWCNTs@carbonaceous CoO composite is prepared via wet chemical and pyrolysis method. • The composite can reach −50.2 dB at 14.3 GHz with the thickness of 1.84 mm. • The composite exhibits a bandwidth of 13.2 GHz at RL ≤ −10 dB in the range of 1.0–4.0 mm. • The composite shows a good performance of impedance match. [ABSTRACT FROM AUTHOR]

Abstract The dielectric-dielectric composite (SRGA) for electromagnetic absorber was fabricated via integrating Ag(I)-Schiff base coordination compounds (SSBCC) with three-dimensional reduced graphene aerogel (3D-rGA) powders. SRGA showed excellent electromagnetic wave absorption properties in terms of reflection loss, absorption band width and absorber thickness. Specially, when the mass ratio of SSBC to 3D-rGA powders was 1:3 (SRGA-25), the maximum value of reflection loss at 2 mm was up to −63.82 dB and the effective frequency bandwidth of 6.28 GHz (10.16–16.44 GHz) at 2.5 mm can be obtained. The mechanism investigation of electromagnetic wave absorption for SRGA showed that the enhanced electromagnetic wave absorption was ascribed to enhanced polarization loss derived from good 3D-conductive-network units of 3D-rGA, abundant interfaces caused by the media heterostructure due to the introduction of SSBCC and the good impedance matching condition. And 3D-rGA based materials might be put into practical application only in powder state due to the very low strength of the buck state. Therefore, the investigation on SRGA in our contribution is considered to be an actual performance evaluation of the materials based on three-dimensional graphene for microwave attenuation. This work also provided a method for fabricating excellent graphene-based electromagnetic wave absorbers by simply mixing a suitable dielectric lossy material, e.g. SSBCC. Graphical abstract Image 1 Highlights • The preparation method of SRGA through mixing components is simple. • 3D-rGA powers overcome the limitation of low strength of graphene aerogel. • Schiff base enhances dielectric properties and makes SRGA good impedance matching. • The max RL at 2 mm is up to −63.82 dB and the effective bandwidth reaches 6.28 GHz. [ABSTRACT FROM AUTHOR]

Abstract In the present study, an electromagnetic (EM) wave absorber was fabricated with a multi-walled carbon nanotube (MWNT)-incorporated cement composite and the absorbing capability of the absorber was assessed. To disperse MWNTs in a cement matrix, composites were fabricated under a low flow condition of the fresh mixture, and silica fume (SF) was added to explore the influence of SF addition on MWNT distribution. The electrical conductivity of the composite was evaluated to examine the MWNT distribution and the complex permittivity was determined to study the EM characteristics of the composite. The conductivity results demonstrated that SF addition of 10 wt% led to the greatest enhancement. Meanwhile, the absorber was designed on the basis of complex permittivity at a frequency point of 9.4 GHz, and SF0-M1.0 type (no SF addition and MWNT content of 1.0 wt%) and SF10-M0.6 type (SF content of 10 wt% and MWNT content of 0.6 wt%) were employed. The experimental assessment of the absorbing capability demonstrated that the −10 dB bandwidths of SF0-M1.0 and SF10-M0.6 type absorbers were 2.5 GHz and 3.2 GHz, respectively. In addition, the absorbing capability derived from the experimental work was compared and validated by means of computational simulation work. [ABSTRACT FROM AUTHOR]

W-type Sr-hexaferrites, Sr 0.75 Ca 0.25 Zn 2- x Co x Fe 16 O 27 (0.0 ≤ x ≤ 2.0), were synthesized, and their magnetic and electromagnetic (EM) wave absorption properties were investigated. As x increased from 0.0 to 2.0, the saturation magnetization value increased and reached a maximum at x = 1.25, followed by a decrease, while the magnetic anisotropic field (H ani) decreased and showed a minimum at x = 1.0, then increased again. The variation in H ani could be controlled by adjusting the value of x , which also changed the ferromagnetic resonance (FMR) frequency and enabled control over the frequency band of EM wave absorption. It is demonstrated that the EM wave absorption is primarily controlled by imaginary part of permeability (μ") induced by FMR. Composite of the W-type hexaferrite-epoxy (10 wt%) with x = 0.75–2.0 showed a broad-band EM wave absorption in the 1–18 GHz range, while the composites with x = 0–0.4 showed it in the 26.5–40 GHz. The x = 1.25 sample satisfied RL < − 10 dB in the 7–17 GHz range with a thickness of 2.1 mm, while x = 0.3 sample satisfied RL < − 10 dB in the 27–39 GHz with a thickness of 0.8 mm. Sr 0.75 Ca 0.25 Zn 2- x Co x W is a very promising material for tunable wideband EM wave absorbers in 1–40 GHz range. • H ani of Sr 0.75 Ca 0.25 Zn 2- x Co x W could be controlled by Co-doping level x , which also changed the FMR frequency. • EM wave absorption is primarily controlled by μ" induced by FMR. • Sr 0.75 Ca 0.25 Zn 2- x Co x W-epoxy composites exhibited tunable and broad-band EM wave absorption within 1–40 GHz range. [ABSTRACT FROM AUTHOR]

Two-dimensional nanomaterial MXene Ti 3 C 2 T x with excellent electrical conductivity has received extensive attention in the electromagnetic wave (EMW) absorption field. However, the excessively high permittivity of Ti 3 C 2 T x is not conducive to impedance matching and the absorption of EMW. Considering the low permittivity and mesoporous structure of MOF, in this work, Co/La-MOF were in situ growth on the surfaces of Ti 3 C 2 T x by a facile co-solvothermal method. The obtained Co/La-MOF anchored on Ti 3 C 2 T x (Co/La-MOF/Ti 3 C 2 T x) composite exhibits low density with excellent EMW absorption performance. Co/La-MOF/Ti 3 C 2 T x -2 (Co2+/La3+ mass ratio of 16:3) shows the minimum reflection loss of − 44.15 dB at 4.00 GHz with the effective absorption bandwidth of 3.67 GHz in the frequency range of 14.03–17.70 GHz under 1.3 mm. In addition, the electromagnetic absorption mechanism of Co/La-MOF/Ti 3 C 2 T x was also investigated. It provides an effective strategy for the preparation of a novel absorber with high EMW absorbing performance. • Two-dimensional Ti 3 C 2 T x MXene and Co/La-MOF with porous structure were synthesized by in-situ growth method. • Co/La-MOF/Ti 3 C 2 T x exhibits an excellent electromagnetic absorption performance. • The RL min of Co/La-MOF/Ti 3 C 2 T x is − 44.15 dB at 4.00 GHz under 4.5 mm, the EAB is 3.67 GHz under 1.3 mm. • EMW absorption performance of samples can be regulated by adjusting the Co2+/La3+ mass ratio. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI)-coated Y 3 Fe 5 O 12 (YIG)/CoFe 2 O 4 (CFO) hybrid composites were synthesized via sol-gel and oxidative polymerization methods to achieve advanced microwave absorption properties. The structural, morphological, magnetic, and microwave absorption characteristics of the resulting samples were analyzed by performing X-ray diffraction (XRD), scanning electron microscopy (SEM), vibration sample magnetometer (VSM), and vector network analyzer (VNA). XRD results revealed that CFO and YIG have cubic crystal structures with Fd3m and Ia3d space symmetry, respectively, with an average crystallite size of 35.3 nm and 42.9 nm. The Ferro/ferrimagnetic signals were detected from the ferrite samples' room temperature magnetic hysteresis loops. The incorporation of PANI and YIG into the composites resulted in a decrease in their magnetic saturation (M s) and coercive field (Hc) values. VNA measurements demonstrated that nearly all samples achieved 90% absorption (≤−10 dB) of incident electromagnetic waves throughout the X -band frequency range. The minimum reflection loss (RL min) value reaches − 47.34 dB at 8.14 GHz, with an effective bandwidth of 4.00 GHz, covering the entire X -band and beyond. These impressive absorption characteristics suggest that the manufactured composites possess potential as viable candidates for defense applications conducted at X -band frequency. [Display omitted] • PANI/[YIG x /CFO 1−x ] hybrid composites were synthesized by in-situ polymerization of aniline followed by the sol-gel route. • All manufactured samples, except PYC06, absorb 90% of incident EMW through X-band frequency. • The RL min value is found as − 47.34 dB at 8.14 GHz with effective bandwidth of 4.00 GHz (entire X-band) for PYC02 sample [ABSTRACT FROM AUTHOR]

Recently, with the pursuit of high-efficiency electromagnetic wave absorption (EMWA) and electrochemical energy storage (EES) materials, multifunctional lignin-based composites have attracted significant interest due to their low cost, vast availability, and sustainability. In this work, lignin-based carbon nanofibers (LCNFs) was first prepared by electrospinning, pre-oxidation and carbonization processes. Then, different content of magnetic Fe 3 O 4 nanoparticles were deposited on the surface of LCNFs via the facile hydrothermal way to produce a series of bifunctional wolfsbane-like LCNFs/Fe 3 O 4 composites. Among them, the synthesized optimal sample (using 12 mmol of FeCl 3 ·6H 2 O named as LCNFs/Fe 3 O 4 –2) displayed excellent EMWA ability. When the minimum reflection loss (RL) value achieved −44.98 dB at 6.01 GHz with an thickness of 1.5 mm, and the effective absorption bandwidth (EAB) was up to 4.19 GHz ranging from 5.10 to 7.21 GHz. For supercapacitor electrode, the highest specific capacitance of LCNFs/Fe 3 O 4 –2 reached 538.7 F/g at the current density of 1 A/g, and the capacitance retention remained at 80.3 %. Moreover, an electric double layer capacitor of LCNFs/Fe 3 O 4 –2//LCNFs/Fe 3 O 4 –2 also showed a remarkable power density of 7755.29 W/kg, outstanding energy density of 36.62 Wh/kg and high cycle stability (96.89 % after 5000 cycles). In short, the construction of this multifunctional lignin-based composites has potential applications in electromagnetic wave (EMW) absorbers and supercapacitor electrodes. [Display omitted] • Bifunctional wolfsbane-like composites were prepared as electromagnetic wave absorbers and supercapacitor electrodes. • Increasing magnetic Fe 3 O 4 nanoparticles contents in the composites optimized the properties of EMWA and EES. • The optimal sample exhibited the minimum RL value of -44.98 dB at 6.01 GHz with an thickness of 1.5 mm. • In three-electrode, the best sample displayed high specific capacitance of 538.7 F/g at the current density of 1 A/g. • In two-electrode, an outstanding energy density of 36.62 Wh/kg at the power density of 7755.29 W/kg was achieved. [ABSTRACT FROM AUTHOR]

Recently, multifunctional lignin-based materials are gaining more and more attention due to their great potential for low-cost and sustainability. In this work, to obtain both an excellent supercapacitor electrode and an outstanding electromagnetic wave (EMW) absorber, a series of multifunctional nitrogen-sulphur (N-S) co-doped lignin-based carbon magnetic nanoparticles (LCMNPs) had been successfully prepared through Mannich reaction at different carbonization temperature. As compared with the directly carbonized lignin carbon (LC), LCMNPs had more nano-size structure and higher specific surface area. Meanwhile, with the increase of carbonization temperature, the graphitization of the LCMNPs could also be effectively improved. Therefore, LCMNPs-800 displayed the best performance advantages. For the electric double layer capacitor (EDLC), the optimal specific capacitance of LCMNPs-800 reached 154.2 F/g, and the capacitance retention after 5000 cycles was as high as 98.14 %. When the power density was 2204.76 W/kg, the energy density achieved 33.81 Wh/kg. In addition, N-S co-doped LCMNPs also exhibited strong electromagnetic wave absorption (EMWA) ability, whose the minimum reflection loss (RL) value of LCMNPs-800 was realized −46.61 dB at 6.01 GHz with an thickness of 4.0 mm, and the effective absorption bandwidth (EAB) was up to 2.11 GHz ranging from 5.10 to 7.21 GHz, which could cover the C-band. Overall, this green and sustainable approach is a promising strategy for the preparation of high-performance multifunctional lignin-based materials. [Display omitted] • Multifunction N-S co-doped LCMNPs were prepared as supercapacitor electrode and electromagnetic wave absorber. • Increasing the carbonization temperature was an effective strategy for preparing multifunction N-S co-doped LCMNPs. • LCMNPs-800 could display high specific capacitance of 474.8 F/g at a current density of 0.5 A/g. • LCMNPs-800 could exhibit excellent cycling stability of 98.14 % after 5000 cycles. • The minimum RL reach −46.61 dB at 6.01 GHz with an EAB of 2.11 GHz at a thickness of 4.0 mm. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, the periodic structure-based absorber operating at dual-band or more for applying to new electromagnetic wave measurement facility that does not contain a conventional pyramidal absorber is presented. To achieve the objective, the absorber structure takes the format of two-layer periodic surfaces. Based on the logical design principles, the parametric study results to obtain the desired performance and the final experimental result are addressed. The measured result shows a broadband reflectivity characteristic from 0.60 to 3.27 GHz on the basis of below −10 dB. As a result, the absorber shows the performance supporting CDMA, WCDMA, and WLAN bands in the electromagnetic wave measurement facility. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:478-481, 2017 [ABSTRACT FROM AUTHOR]

The electromagnetic wave absorption properties of single- and double-layer silver nanoparticle/carbon nanotube (Ag/CNT) nanocomposites were evaluated. The reflection loss (R.L.) of the samples was calculated based on the measured complex permittivity and permeability. The double-layer composites constructed from CNT 30 wt.% and Ag/CNT 30 wt.% with total thickness of 3.3 mm showed a minimum R.L. of ∼−52.9 dB (over 99.999% absorption) at 6.3 GHz. The bandwidth of reflection loss less than −10 dB was observed at 3 regions, with wideness of 3.5, 0.8, and 1.5 GHz. Thin absorber with large R.L. and wide response bandwidth at low and high frequency regions can be obtained with double-layer composites. The capability to modulate the absorption and bandwidth of these samples to suit various applications in different frequency bands indicates that these nanocomposites could be an excellent electromagnetic wave absorber. [ABSTRACT FROM AUTHOR]

• (PEA) 2 PbBr 4 /CNTs with an ultra-wide absorption bandwidth (5.12 GHz). • Polarization loss in conductive network construction. • The first study of 2D perovskite as microwave absorber. • Expand the application field of 2D perovskite. Two-dimensional (2D) hybrid halide perovskites have shown great potential for application in the field of electromagnetic wave (EMW) absorption thanks to their inherent high-equilibrium electron hole and electron mobility as well as enhanced water-resistance and photo-stability. However, research on the application in EMW absorption has never been reported. Here, we first design the (PEA) 2 PbBr 4 /CNTs wave-absorption system. By adjusting the component ratio, the 2D perovskite-based composite shows an excellent wave absorbing performance. The maximum effective absorption bandwidth reaches 5.12 GHz at 1.74 mm (12.28–17.40 GHz) and a minimum reflection loss of −56.88 dB at 1.90 mm, respectively, as the component mass ratio is 12:1. This outstanding performance is attributed to the combined action of multiple loss mechanisms and provide a great potential of 2D perovskite for application in EMW absorption. [ABSTRACT FROM AUTHOR]

Barium titanate/carbon nanotube (BTO/CNT) hybrid nanocomposites were fabricated by sol–gel method. The BTO/CNT hybrid nanomaterials were characterized using X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, Raman and X-ray photoelectron spectroscopy. The BTO/CNT hybrid nanomaterials were then loaded in paraffin wax with different weight percentage, and pressed into toroidal shape with thickness of 1.0 mm to evaluate their complex permittivity and complex permeability using vector network analyzer. The reflection loss of the samples was calculated according to their measured complex permittivity and permeability. The minimum reflection loss of the BTO/CNT 60 wt.% hybrid nanocomposites sample with a thickness of 1.0 mm reached 29.6 dB (over 99.9% absorption) at 13.6 GHz, and also exhibited a wide response bandwidth where the frequency bandwidth of the reflection loss of less than −10 dB (over 90% absorption) was from 12.1 to 13.8 GHz. The BTO/CNT 60 wt.% hybrid nanocomposites with thickness of 1.1 mm showed a minimum reflection loss of ∼−56.5 dB (over 99.999% absorption) at 13.2 GHz and was the best absorber when compared with the other samples of different thickness. The reflection loss peak shifted to lower frequency and wider response bandwidth can be obtained as the thickness of the samples increased. The capability to modulate the absorption band of these samples to suit various applications in different frequency bands simply by manipulating their weight percentage and thickness indicates that these hybrid nanocomposites could be a promising electromagnetic wave absorber. [ABSTRACT FROM AUTHOR]

Hierarchical structural design has been proved to be a new strategy for fabricating high-performance microwave absorbers, so some researchers use low–dimensional components to construct continuous networks for better performance. In this work, the novel hierarchical carbon fibers@ZIF–67@MoS 2 film with tunable and efficient electromagnetic wave (EMW) absorption performance was obtained by the electrostatic spinning of ZIF–67 in the interior of carbon fibers and subsequent hydrothermal of MoS 2. By the synergistic effects from the ZIF–67 particles increasing the magnetic loss and MoS 2 at the outer layer improving the impendence matching, the absorption property of CPZM–1 could be summarized as follow: the optimal reflection loss(RL) was −72.7 dB with a thickness of 2.6 mm at 10.0 GHz and the corresponding effective absorption bandwidth (EAB) of 9.8 GHz covered whole X and Ku band. Moreover, by adjusting the load of ZIF–67, CPZM–5 achieved the maximum EAB of 12.5 GHz. [ABSTRACT FROM AUTHOR]

Abstract: Sm2O3/α-Fe/Sm2Fe17N x composites were prepared in situ by hydrogenation–disproportionation–oxygen-desorption–recombination and nitrogen process, and their electromagnetic wave absorption properties were measured in the frequency range of 0.5–18GHz. The result showed that saturation magnetization and coercivity of as-prepared powder with 25.3wt% Sm2O3, 64.4wt% α-Fe and 10.3wt% Sm2Fe17N3 were 134.57emu/g and 654.5G, respectively. The dielectric constant of composites was low over the frequency range of 0.5–18GHz, and their resonance frequencies were at a high frequency range. The resin composite of Sm2O3/α-Fe/Sm2Fe17N3 exhibited effective electromagnetic wave absorption (RL≤20dB) in a frequency range 3–9GHz, for absorber thickness ranging from 3 to 8mm, respectively. A minimum reflection loss of −53dB from the samples was observed at 7GHz with an absorber thickness of 3.59mm. [Copyright &y& Elsevier]

This article shows some results related to the optimum design of a multilayered electromagnetic absorber, in the frequency range between 0.85 GHz and 5.4 GHz, which belongs to wireless communications. For this design, the Unified Particle Swarm Optimization (UPSO) metaheuristic was used. The results agree with those previously obtained using the standard Particle Swarm Optimization (PSO) algorithm and the deterministic method of interval analysis, which were previously reported. An important reduction on computation time was achieved, although a limited results reproducibility persists. [ABSTRACT FROM AUTHOR]

In this study, Cu 3 (1,3,5-benzenetricarboxylate) (Cu-BTC) metal-organic frameworks decorated with Fe 3 O 4 nanoparticles were synthesized via the hydrothermal process. Subsequently, the obtained Fe 3 O 4 /Cu-BTC was coated by poly(3,4-ethylenedioxythiophene) (PEDOT) via in situ chemical polymerization methods. The chemical, structural, and magnetic hysteresis analysis of particles were carried oud via scanning electron microscope (SEM), X-ray diffractometer (XRD), vibrating sample magnetometer (VSM), and fourier transform infrared spectroscopy (FTIR) machines. The characteristic peaks of C/F and P@C/F were obtained without any other impurities and extra peaks. The Fe 3 O 4 decorated Cu-BTC displayed octahedral morphology with average particle size of 150–170 nm. As an electromagnetic wave absorber, the obtained Fe 3 O 4 decorated Cu-BTC was mixed with 45% by weight of paraffin. For comparative studies, the PEDOT coated Fe 3 O 4 /Cu-BTC was also filled to the paraffin matrix. The higher real and imaginary part of permittivity values were obtained with introduction of conductive PEDOT shell. The electromagnetic wave absorption performance of composites was determined with permeability and permittivity values. The result exhibited that the strongest reflection loss was −18.3 dB at 17.5 GHz frequency with a thickness of 5 mm for PEDOT coated Fe 3 O 4 /Cu-BTC composite. It was proved that the conductive PEDOT coating on Fe 3 O 4 /Cu-BTC enhanced electromagnetic wave absorption capability of composite and the PEDOT coated Fe 3 O 4 /Cu-BTC can be considered as a good candidate for electromagnetic wave absorption applications. • Cu 3 (1,3,5-benzenetricarboxylate) (Cu-BTC) metal-organic frameworks decorated with Fe3O4 nanoparticles were synthesized. • The PEDOT coated Fe 3 O 4 /Cu-BTC was successfully prepared. • The sample with 45 wt% loading exhibits optimal R L characteristics. • RL min of the sample is −18.3 dB with a broad effective bandwidth of 2 GHz at 5 mm. [ABSTRACT FROM AUTHOR]