Dielectric Loss Mechanism in Electromagnetic Wave Absorbing Materials

Advanced Science, Journal Year: 2022, Volume and Issue: 9(10)

Published: Feb. 7, 2022

Electromagnetic (EM) wave absorbing materials play an increasingly important role in modern society for their multi-functional military stealth and incoming 5G smart era. Dielectric loss EM absorbers underlying mechanism investigation are of great significance to unveil attenuation behaviors guide novel dielectric design. However, current researches focus more on synthesis rather than in-depth study. Herein, comprehensive views toward mechanisms including interfacial polarization, dipolar conductive loss, defect-induced polarization provided. Particularly, some misunderstandings ambiguous concepts each highlighted. Besides, study emphasized. Moreover, new regulation strategies instead regular components compositing summarized provide inspiring thoughts simple effective behavior modulation.

Language: Английский

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Dimensional Design and Core–Shell Engineering of Nanomaterials for Electromagnetic Wave Absorption

Advanced Materials, Journal Year: 2021, Volume and Issue: 34(11)

Published: Nov. 10, 2021

Abstract Electromagnetic (EM) wave absorption materials possess exceptionally high EM energy loss efficiency. With vigorous developments in nanotechnology, such have exhibited numerous advanced functions, including radiation prevention and antiradar stealth. To achieve improved performance multifunctionality, the elaborate control of microstructures has become an attractive research direction. By designing them as core–shell structures with different dimensions, combined effects, interfacial polarization, conduction networks, magnetic coupling, magnetic–dielectric synergy, can significantly enhance performance. Herein, advances low‐dimensional are outlined a selection most remarkable examples is discussed. The derived key information regarding dimensional design, structural engineering, performance, structure–function relationship comprehensively summarized. Moreover, investigation cutting‐edge mechanisms given particular attention. Additional applications, oxidation resistance self‐cleaning also introduced. Finally, insight into what may be expected from this rapidly expanding field future challenges presented.

Language: Английский

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Heterointerface Engineering in Electromagnetic Absorbers: New Insights and Opportunities

Advanced Materials, Journal Year: 2021, Volume and Issue: 34(4)

Published: Oct. 4, 2021

Electromagnetic (EM) absorbers play an increasingly essential role in the electronic information age, even toward coming "intelligent era". The remarkable merits of heterointerface engineering and its peculiar EM characteristics inject a fresh infinite vitality for designing high-efficiency stimuli-responsive absorbers. However, there still exist huge challenges understanding reinforcing these interface effects from micro macro perspectives. Herein, response mechanisms interfacial are dissected depth, with focus on advanced characterization as well theoretical techniques. Then, representative optimization strategies systematically discussed emphasis component selection structural design. More importantly, most cutting-edge smart functional devices based reported. Finally, current concrete suggestions proposed, future perspectives this promising field also predicted.

Language: Английский

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Ultrabroad Microwave Absorption Ability and Infrared Stealth Property of Nano-Micro CuS@rGO Lightweight Aerogels

Nano-Micro Letters, Journal Year: 2022, Volume and Issue: 14(1)

Published: Aug. 20, 2022

Developing ultrabroad radar-infrared compatible stealth materials has turned into a research hotspot, which is still problem to be solved. Herein, the copper sulfide wrapped by reduced graphene oxide obtain three-dimensional (3D) porous network composite aerogels (CuS@rGO) were synthesized via thermal reduction ways (hydrothermal, ascorbic acid reduction) and freeze-drying strategy. It was discovered that phase components (rGO CuS phases) micro/nano structure (microporous nanosheet) well-modified modulating additive amounts of changing ways, resulted in variation pore structure, defects, complex permittivity, microwave absorption, radar cross section (RCS) value infrared (IR) emissivity. Notably, obtained CuS@rGO with single dielectric loss type can achieve an bandwidth 8.44 GHz at 2.8 mm low filler content 6 wt% hydrothermal method. Besides, aerogel realizes minimum reflection (RLmin) - 60.3 dB lower 2 wt%. The RCS reach 53.3 m2, effectively reduces probability target being detected detector. Furthermore, laminated architecture multicomponent endowed insulation IR versatility. Thus, this work offers facile method design develop rGO-based absorbers radar-IR stealth.

Language: Английский

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Ultralight Magnetic and Dielectric Aerogels Achieved by Metal–Organic Framework Initiated Gelation of Graphene Oxide for Enhanced Microwave Absorption

Nano-Micro Letters, Journal Year: 2022, Volume and Issue: 14(1)

Published: April 19, 2022

Metal-organic frameworks (MOFs) are used to directly initiate the gelation of graphene oxide (GO), producing MOF/rGO aerogels. The ultralight magnetic and dielectric aerogels show remarkable microwave absorption performance with ultralow filling contents. development a convenient methodology for synthesizing hierarchically porous comprising metal-organic (GO) building blocks that exhibit an density uniformly distributed MOFs on GO sheets is important various applications. Herein, we report facile route MOF/reduced (rGO) based GO, which initiated using MOF crystals. Free metal ions exposed surface MIL-88A nanorods act as linkers bind nanosheets three-dimensional network via metal-oxygen covalent or electrostatic interactions. MOF/rGO-derived Fe3O4@C/rGO Ni-doped notable (MA) performance, simultaneously achieving strong broad bandwidth at low thickness 2.5 (- 58.1 dB 6.48 GHz) 2.8 mm 46.2 7.92 contents 0.7 0.6 wt%, respectively. attenuation ability prepared further confirmed radar cross-sectional simulation, attributed synergistic effects their structures heterointerface engineering. This work provides effective pathway fabricating hybrid offers MA.

Language: Английский

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Environmentally Tough and Stretchable MXene Organohydrogel with Exceptionally Enhanced Electromagnetic Interference Shielding Performances

Nano-Micro Letters, Journal Year: 2022, Volume and Issue: 14(1)

Published: March 21, 2022

Conductive hydrogels have potential applications in shielding electromagnetic (EM) radiation interference deformable and wearable electronic devices, but usually suffer from poor environmental stability stretching-induced performance degradation. Although organohydrogels can improve the of materials, their development is at expense reducing electrical conductivity thus weakening EM ability. Here, a MXene organohydrogel prepared which composed network for electron conduction, binary solvent channels ion abundant solvent-polymer-MXene interfaces wave scattering. This possesses excellent anti-drying ability, low-temperature tolerance, stretchability, shape adaptability, adhesion rapid self-healing Two effective strategies been proposed to solve problems current materials. By reasonably controlling content glycerol-water ratio gel, exhibit exceptionally enhanced performances compared hydrogel due increased physical cross-linking density gel. Moreover, shows attractive stretching-enhanced effectiveness, caused by connection parallel arrangement nanosheets. well-designed has devices.

Language: Английский

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Synergistic Polarization Loss of MoS₂‐Based Multiphase Solid Solution for Electromagnetic Wave Absorption

Advanced Functional Materials, Journal Year: 2022, Volume and Issue: 32(18)

Published: Jan. 24, 2022

Abstract Given tunable hybridization structures in solid solutions, fascinating electromagnetic (EM) properties can be achieved for regulating EM wave (EMW) absorption. Herein, a novel metal–organic cooperative interactions method is proposed to manipulate the vacancy, interstitial, substitutional, and heterointerface molybdenum disulfide (MoS 2 ) solution simultaneously, thence meeting synergistic polarization loss on various point face sites. Assisted by coordination between Cu 2+ polydopamine (PDA), effect of modification MoS highly improved, which further lead S interstitial Cu, substitutional N, carbon . Contributing synergetic among multiple polarizations, Cu/C@MoS exhibit ultrahigh EMW absorption performance, EMA with twice PDA delivers effective bandwidth 7.12 GHz minimum reflection −48.22 dB (2.5 mm). The energy attenuation improved almost 266.7% 222.2% than C@MoS Cu@MoS , respectively. Finally, this work reveals structural dependency materials establishes an entirely new model.

Language: Английский

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Synthesis of CuCo2S4@Expanded Graphite with crystal/amorphous heterointerface and defects for electromagnetic wave absorption

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Sept. 23, 2023

The remarkable advantages of heterointerface and defect engineering their unique electromagnetic characteristics inject infinite vitality into the design advanced carbon-matrix wave absorbers. However, understanding interface dipole effects based on microscopic macroscopic perspectives, rather than semi-empirical rules, can facilitate heterointerfaces defects to adjust impedance matching absorption material, which is currently lacking. Herein, CuCo2S4@Expanded Graphite heterostructure with multiple cation are reported, morphology, interfaces component regulated by varying concentration metal ions. results show that 3D flower-honeycomb crystal-crystal/amorphous abundant effectively conductive polarization losses, achieve balance carbon materials, improve wave. For sample CEG-6, effective Ku band RLmin -72.28 dB bandwidth 4.14 GHz realized at 1.4 mm, while filler loading only 7.0 wt. %. This article reports establishment potential relationship between heterointerfaces, defects, materials.

Language: Английский

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NiO/Ni Heterojunction on N‐Doped Hollow Carbon Sphere with Balanced Dielectric Loss for Efficient Microwave Absorption

Small, Journal Year: 2023, Volume and Issue: 19(12)

Published: Jan. 1, 2023

Hollow carbon spheres are potential candidates for lightweight microwave absorbers. However, the skin effect of pure carbon-based materials frequently induces a terrible impedance mismatching issue. Herein, small-sized NiO/Ni particles with heterojunctions on N-doped hollow (NHCS@NiO/Ni) constructed using SiO2 as sacrificing template. The fabricated NHCS@NiO/Ni displayed excellent absorbability minimum reflection loss -44.04 dB matching thickness 2 mm and wider efficient absorption bandwidth 4.38 GHz 1.7 mm, superior to most previously reported Experimental results demonstrated that property attributed balanced dielectric optimized characteristic due presence heterojunctions. Theoretical calculations suggested redistribution charge at interfaces formation dipoles induced by N dopants defects responsible enhanced conduction polarization losses NHCS@NiO/Ni. simulations surface current power densities reveal has- applicable attenuation ability toward under practical application scenario. This work paves an way reasonable design well-defined nanostructures high-efficiency absorption.

Language: Английский

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Morphology control of eco-friendly chitosan-derived carbon aerogels for efficient microwave absorption at thin thickness and thermal stealth

Green Chemistry, Journal Year: 2022, Volume and Issue: 24(13), P. 5280 - 5290

Published: Jan. 1, 2022

In the face of increasingly severe electromagnetic wave pollution, research biomass-based carbon materials due to advantages being green, renewable, environment-friendly, porous and light has become one most attractive topics.

Language: Английский

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