High-efficiency Electromagnetic Wave Absorption Research Articles

Fabrication of Ni/ZnO/C hollow microspheres decorated graphene composites towards high-efficiency electromagnetic wave absorption in the Ku-band

Developing light-weight, thin thickness and high-efficiency electromagnetic wave (EMW) absorbers is an effective strategy for dealing with the increasingly serious problem of electromagnetic radiation pollution. Herein, nickel/zinc oxide/carbon (Ni/ZnO/C) hollow microspheres decorated graphene composites were facilely prepared through the high-temperature pyrolysis of bimetallic NiZn metal-organic frameworks (MOFs) precursors. Morphological characterization results manifested that the Ni/ZnO/C microspheres with unique hollow structure were almost evenly anchored on the wrinkled surfaces of flake-like graphene. Moreover, the influences of additive amounts of graphene oxide (GO) in the MOFs precursors on the crystal structure, graphitization degree, micromorphology, magnetic properties, electromagnetic parameters and EMW absorption performance were investigated in detail. It was found that the superior EMW absorption performance could be achieved through facilely adjusting the additive amounts of GO in the precursors. As the additive amount of GO was equal to 60 mg, the obtained composite showed the comprehensive excellent EMW absorption performance. Notably, the optimal minimum reflection loss reached −57.5 dB at 16.5 GHz in the Ku-band under an ultrathin matching thickness of merely 1.34 mm, and the broadest effective absorption bandwidth achieved 5.6 GHz (from 12.4 to 18 GHz) when the thickness was 1.5 mm. Furthermore, the underlying EMW absorption mechanisms of as-prepared composites were revealed. It was believed that our results could be valuable for the structural design and EMW absorption performance modulation for MOFs derived magnetic carbon composites.

Enhanced electromagnetic wave absorption of layered FeCo@carbon nanocomposites with a low filler loading

Metal-organic frameworks (MOFs) derived carbon-based magnetic metal materials had attracted much attention in the field of electromagnetic wave absorbers. In this work, a layered FeCo@C nanocomposites was successfully synthesized by annealing FeCo-MOFs. The pyrolytic temperatures had influenced the graphitization degree of the carbon frameworks and the magnetic properties of the FeCo nanoparticles. Owing to the outstanding attenuation capacity, impedance matching and unique layered structure, FeCo@C nanocomposites displayed an excellent electromagnetic wave absorption performance with the strongest reflection loss (RL) value could reach to −53.6 dB at 12.8 GHz and the effective bandwidth (RL<−10 dB) could reach 6 GHz (10.4–16.4 GHz) at the thickness of 2.5 mm with the filler loading was only 15 wt%. Therefore, the layered FeCo@C nanocomposites could be a potential high-efficiency electromagnetic wave absorption material with lightweight, wide effective absorption bandwidth, and strong absorption characteristics.

Fabrication of yolk-shell NiCo alloy@C composites derived from trimetallic metal–organic frameworks as light-weight and high-performance electromagnetic wave absorbers

Developing the high-performance electromagnetic wave (EMW) absorbers with the characteristics of thin thickness, broad bandwidth and strong absorption against the increasingly serious electromagnetic pollution was still a great challenge. In this work, NiCo alloy@C (NCC) composites were fabricated through high-temperature pyrolysis of trimetallic NiCoZn metal-organic framework. Results showed that the NCC composites displayed a unique yolk-shell structure, and the carbonization temperature had a great influence on the crystal structure, graphitization degree and micromorphology. Moreover, the electromagnetic parameters and absorption capacity could be regulated by adjusting the carbonization temperature and filler contents. Significantly, the obtained NCC composite presented the integrated optimal absorption capacity, including the minimum reflection loss of −61.9 dB under an ultrathin thickness of 1.5 mm and a wide absorption bandwidth of 6.0 GHz at 1.7 mm. Additionally, the underlying absorption mechanisms were revealed. Our results could offer a new approach to fabricate light-weight and high-efficiency EMW absorbers.

Construction of low-frequency and high-efficiency electromagnetic wave absorber enabled by texturing rod-like TiO2 on few-layer of WS2 nanosheets

As a novel 2D transition metal sulfide material, WS2 has been proven to possess potential electromagnetic wave absorption (EMWA) property due to its peculiar electronic structure. However, the intrinsic weak impedance match and single dielectric loss domination of this material only produce high-frequency electromagnetic absorption (EMA), which is seemingly futile for the prevalent low-band 4G and 5G EMW. In this study, efforts have been made to effectively texture rod-like TiO2 semiconductor with different mass ratios on the a few layers of WS2 nanosheets via a simple step-by-step hydrothermal method. It is found that the WS2/TiO2 hybrids loaded with 10% TiO2 at a sample thickness of 5.30 mm, the minimum RL is −43.90 dB at 5.12 GHz. When the thickness of the sample is 2.00 mm, the bandwidth with RL value less than −10 dB can reach 4.70 GHz, and the effective EMA band could be adjusted in a range of 13.84 GHz (4.16–18 GHz) by increasing the thickness from 1.0 mm to 5.5 mm. It was found that the introduction of TiO2 nanosheets with high dielectric loss into the dielectric WS2 nanosheets can produce a synergistic effect. The benefits of such synergestic effect include, optimization of the EMA strength and bandwidth, and a reduction of the effective EMA frequency band from high frequency to low frequency. This study paves a new avenue for the future design of low-frequency EMA materials with high efficiency.

Tunable sulfur vacancies and hetero-interfaces of FeS2-based composites for high-efficiency electromagnetic wave absorption

Controlling Vacancies and heterointerfaces of nano/microstuctures is very challenging, importantly, which tailors the electromagnetic (EM) parameters to develop the high-performance electromagnetic wave (EMW) absorbers. Herein, we report a strategy using various sulfur-source modifying Fe3O4 nanosphere by one-step hydrothermal method to prepare a series of FeS2-based composites. Diverse sulfur sources determine their morphologies, crystal structures and compositions, and further affect EMW absorption abilities. Among these materials, rich sulfur vacancies and abundant heterogeneous interfaces improve their conduction loss and polarization loss caused by a unique concave cubic polyhedrons structure of the Fe3O4/FeS2 composites fabricated by thioacetamide (TAA), which displays the brilliant EMW absorption capacity compared to others. That is, it possesses the minimum reflection loss (RLmin) of −59.27 dB and effective absorption bandwidth (EAB, RL ≤ -10 dB) of 5.86 GHz at the thin thickness of 1.8 mm. This study opens a new avenue for designing the superior EMW absorbers by tunable sulfur vacancy and heterointerface.

Opportunities and challenges in microwave absorption of nickel-carbon composites.

In recent years, the problem of electromagnetic wave (EMW) pollution has attracted more and more attention with the development of science and technology. In order to solve this complex problem, the research and development of EMW-absorbing materials is crucial. The new absorbing materials should have the characteristics of light weight, high efficiency, wide bandwidth, environmental protection, oxidation resistance, and other characteristics. Traditional single-phase Ni materials exhibit remarkable ferromagnetic behavior and double-loss mechanisms (dielectric loss and magnetic loss), and are considered as efficient EMW absorbers. However, under the action of EMWs, especially in the GHz frequency band, Ni materials tend to produce an eddy current effect, which limits their application prospects. For Ni-based materials, there is much interest in modifying the composite materials by designing a hierarchical structure for their preparation. Traditional, single-phase, carbon-based materials have been widely used in related fields because of their light weight and good conductivity. However, a single-loss mechanism will affect the impedance matching of carbon materials, thus affecting their application in the field of absorbing waves. For carbon materials, people use them as a filler or matrix material to fabricate composites with metals, metal oxides, or polymer materials to obtain carbon-containing absorbing materials. This paper reviews the evaluation and design principles of the absorbing properties of EMW-absorbing materials. Then, the progress of modified single-phase Ni-based materials (designed materials with 0D, 1D, 2D, and 3D structures), the development of carbon materials (carbon black, carbon nanotubes, carbon fiber, graphite oxide, reduced graphene oxide, and biomedical carbon), and the research progress of Ni-C composite materials (the composite material formed by nickel and carbon) are reviewed. The ultimate goal is to obtain absorbers with light weight, strong absorbing ability, and a wide frequency band. In particular, Ni-MXene, Ni-biomedical carbon, and Ni-multiphase carbon composites are the target direction for designing new and high efficiency EMW absorbers. Finally, the basic challenges and opportunities in this field are discussed.

Synthesis of nitrogen-doped reduced graphene oxide/cobalt-zinc ferrite composite aerogels with superior compression recovery and electromagnetic wave absorption performance.

Graphene aerogels possessing a three-dimensional (3D) porous netlike structure, good electrical conductivity and ultralow density have been widely regarded as a promising candidate for high-efficiency electromagnetic wave (EMW) absorption. Herein, nitrogen-doped reduced graphene oxide/cobalt-zinc ferrite (NRGO/Co0.5Zn0.5Fe2O4) composite aerogels were synthesized through a solvothermal and subsequent hydrothermal self-assembly two-step method. The results of micromorphology analysis showed that the 3D networks were well constructed through the partial stacking of adjacent NRGO sheets, which were decorated with numerous Co0.5Zn0.5Fe2O4 microspheres. The as-synthesized NRGO/Co0.5Zn0.5Fe2O4 composite aerogels have a very low density (12.1-14.6 mg cm-3) and good compression recovery. Moreover, excellent EMW absorption performance could be achieved through facilely regulating the additive volume of ethylenediamine (i.e. nitrogen doping contents) and filler contents. Impressively, the composite aerogel with a doped nitrogen content of 2.5 wt% displayed the optimal minimum reflection loss (RLmin) of -66.8 dB in the X-band at a thickness of 2.6 mm and the broadest effective absorption bandwidth of 5.0 GHz under an ultrathin thickness of merely 1.6 mm. Meanwhile, the RLmin of NRGO/Co0.5Zn0.5Fe2O4 composite aerogels below -20 dB could be reached in almost the whole tested thickness range (1.4-5.0 mm). Additionally, the potential EMW absorption mechanisms were revealed, which was mainly due to the unique 3D porous netlike structure, synergistic effects among conduction loss, magnetic resonance loss and polarization loss, as well as the balanced attenuation capacity and impedance matching. It was believed that this work provided an alternative way for fabricating strong mechanical graphene-based 3D magnetic/dielectric composites as light-weight and high-efficiency EMW absorbers.

Facile preparation of CNTs microspheres as improved carbon absorbers for high-efficiency electromagnetic wave absorption

Carbon nanotubes microspheres (CNTsM) with porous skeleton and net structure were successfully prepared by a facile method of ultrasonic atomization combined with heat treatment. Dielectric characteristics and electromagnetic wave (EMW) absorption properties within the frequency range of 2–18 GHz of CNTsM were studied. Owing to increased multiple reflection/scattering, enhanced interfacial polarization and optimized impedance matching, an excellent EMW absorption performance is therefore obtained for CNTsM. The maximum reflection loss (RL) reaches −35 dB at the thickness of 4.6 mm, and a wide effective absorption bandwidth (EAB, RL < −10dB) of 4.4 GHz is achieved with a thickness of 1.5 mm. CNTsM can be regarded as a brand-new competitive candidate for EMW absorption materials.

Sandwich-like sulfur-free expanded graphite/CoNi hybrids and their synergistic enhancement of microwave absorption

Sulfur-free expanded graphite (EG) was prepared by chemical oxidation, then EG-based cobalt-nickel alloy hybrid (EG@CoNi) was obtained via hydrothermal method in this work. CoNi particles with the diameter of 0.1–0.5 µm were tightly attached to the surface of the layered EG. The incorporation of CoNi was conducive to the absorption of electromagnetic waves due to the increase in Ms and Hc, which enhanced the soft magnetization of EG@CoNi hybrids. The resulting EG@CoNi hybrids exhibited better dielectric loss than CoNi particles, and the optimal value of reflection loss (RL) reached − 50 dB, while the optimal bandwidth less than − 10 dB was 4 GHz, indicating enhanced microwave absorption characteristics. The well impedance matching and electromagnetic wave attenuation of EG@CoNi hybrids benefited from the synergy and double-loss mechanism between CoNi nanoparticles and EG. The dielectric loss in the double-loss mechanism was mainly dipole polarization and interface polarization, while the magnetic loss was mainly the natural ferromagnetic resonance and eddy current loss of CoNi nanoparticles. These multi-layer EG@CoNi hybrids with light weight and high dielectric characteristics would show good application prospects in high-efficiency electromagnetic wave absorbers.

Fabrication of magnesium ferrite microspheres decorated nitrogen-doped reduced graphene oxide hybrid composite toward high-efficiency electromagnetic wave absorption

In this work, magnesium ferrite (MgFe2O4) microspheres decorated nitrogen-doped reduced graphene oxide (NRGO) hybrid composite was fabricated through a solvothermal and hydrothermal two-step method. Results manifested that the three-dimensional netlike structure consisting of MgFe2O4 microspheres and crumpled NRGO was well constructed in the as-synthesized hybrid composite. Significantly, both hybridization with reduced graphene oxide (RGO) and nitrogen doping had few effects on the size of MgFe2O4 microspheres. Furthermore, the influences of hybridization with RGO, nitrogen doping and filler loadings on the electromagnetic absorption properties were carefully examined. It was found that both hybridization with RGO and nitrogen doping were effective strategies to enhance the electromagnetic absorption capacity of MgFe2O4 microspheres. Remarkably, the as-prepared NRGO/MgFe2O4 hybrid composite presented excellent electromagnetic absorption performance, that was the minimum reflection loss of −48.0 dB at 5.2 GHz, and maximum absorption bandwidth of 4.8 GHz under a low filler loading of 25.0 wt% and a small matching thickness of 2.0 mm. In addition, the potential electromagnetic absorption mechanisms were revealed. Therefore, our results could be beneficial to fabricating graphene-based dielectric/magnetic hybrid composites as high-efficiency electromagnetic absorbers.

Facile synthesis of the three-dimensional flower-like ZnFe2O4@MoS2 composite with heterogeneous interfaces as a high-efficiency absorber

Lightweight and high-efficiency microwave absorbers are determined by structure and composition of materials. In this research, a novel core-shell ZnFe2O4@MoS2 composite with a flower-like heterostructure was synthesized successfully by a facile hydrothermal process. The unique 3D heterostructure (porous ZnFe2O4 and MoS2 nanosheets as core and outer shells, respectively) endows the synthesized sample with high-efficiency electromagnetic wave absorption performance. The exploration of microwave absorption properties reveals that the maximum reflection loss displayed by the ZnFe2O4@MoS2 composite is up to −61.8 dB at 9.5 GHz with a filler content of 20 wt%, and the corresponding effective bandwidth (RL exceeding −10 dB) achieves 5.8 GHz (from 7.2 to 13 GHz). The enhanced microwave absorption performance is benefitted by the porous core-shell structure, intense interfacial polarization, multiple reflections, matched impedance and favorable synergistic effect between ZnFe2O4 core and MoS2 shell. Consequently, this strategy provides inspiration for the design of novel microwave absorber with high-performance.

PVP-assisted transformation of ZIF-67 into cobalt layered double hydroxide/carbon fiber as electromagnetic wave absorber

A high efficiency and ultra-light electromagnetic wave (EW) absorber is proposed without precedent. A series of hierarchical short carbon fibers (SCFs) based composites with in-situ grown cobalt layered double hydroxides (Co-LDHs) can be successfully synthesized via a simple PVP-assisted solvothermal method. The synthesized hierarchical structure is composed of 1D SCFs skeleton, 3D hydrangea-like Co-LDHs-1 and 1D rod-like Co-LDHs-2. Notably, ultralight (5 wt% in paraffin matrix), ultrathin (2.1 mm) and ultrawide (6.5 GHz) features are achieved in our composites by simply tuning the doping amount of PVP. The mechanism is explained by the tunable attenuation constant and impedance matching, that is, Co-LDHs-1 and Co-LDHs-2 with different conductivities and morphologies are coordinated to optimize the excessively high complex permittivity of SCFs. This contribution will shed the light on design of LDHs-based materials for light-weight, tuning, and high efficiency EW absorbers.

Facile synthesis of nitrogen-doped reduced graphene oxide/nickel ferrite hybrid nanocomposites with superior electromagnetic wave absorption performance in the X-band

In this work, nitrogen-doped reduced graphene oxide/nickel ferrite (NRGO/NiFe2O4) hybrid nanocomposites were synthesized by a one-pot hydrothermal method. Results manifested that the as-synthesized NiFe2O4 nanoparticles displayed hexagonal morphology with a mean size of 40 nm. Moreover, it was found that the entangled structure consisting of crumpled RGO and hexagonal NiFe2O4 nanoparticles was well constructed in the as-fabricated hybrid nanocomposites. Furthermore, the additive volumes of hydrazine hydrate and filler loadings had significant influences on the electromagnetic wave (EMW) absorption properties of obtained nanocomposites. Remarkably, the NRGO/NiFe2O4 hybrid nanocomposite with 15 mL additive volume of hydrazine hydrate showed the optimal reflection loss of −54.4 dB at 9.2 GHz (X band) under a matching thickness of 2.2 mm and maximum absorption bandwidth of 4.5 GHz (13.5–18 GHz) at a very thin thickness of only 1.5 mm. The dual absorption peaks located at the low and high frequency regions could be achieved by facilely modulating the matching thicknesses. In addition, the underlying EMW absorption mechanisms were uncovered. Therefore, our results could shed light on the design and fabrication of graphene-based dielectric/magnetic hybrid composites as light-weight and high-efficiency EMW absorbers.

Rational design of hierarchical porous Fe3O4/rGO composites with lightweight and high-efficiency microwave absorption

The hierarchical porous flower-like Fe3O4/rGO composites were fabricated through facile microwave-assisted solvothermal method and annealing process. The flower-like Fe3O4 particles were in-situ grown on the rGO. The porous structure led to enhanced multiple reflections and scatterings, facilitating the increased propagation paths and the energy dissipation of electromagnetic wave (EMW). In addition, the construction of hierarchical heterostructure contributed to the strong interfacial polarization and dipole polarization. As a result, the obtained Fe3O4/rGO composites exhibited a minimum reflection loss (RLmin) value of −50.2 dB and a broad effective absorption bandwidth of 4.1 GHz at a matching thickness of only 1.5 mm. Therefore, this work provides a simple and flexible paradigm for the design and synthesis of hierarchical heterostructure as lightweight and high-efficiency EMW absorber.

High efficiency electromagnetic wave absorber derived from transition metal layered double hydroxides

Transition metals and carbon materials are known as electromagnetic wave (EMW) nemesis, which can effectively attenuate EMW in the 2–18 GHz frequency band. Herein, three typical transition metal (Fe, Co, Ni) are freely combined into three layered double hydroxides (LDHs) through hydrothermal method and successfully grown in situ on the surface of short carbon fibers (SCFs). The SEM images show that although the three LDHs (CoNi-LDHs, FeNi-LDHs and FeCo-LDHs) are all sheet-like structures, their respective morphologies are completely different and each has its own merits. After calcination treatment at 500 °C, their distinct morphologies are basically retained, while the EMW absorption properties are greatly improved dramatically. Their effective absorption bandwidth (fe) (RL ≤ −10 dB) reached 3.68 GHz, 1.68 GHz and 4.48 GHz at thicknesses of 2.2 mm, 2.2 mm and 2.0 mm, respectively. As an important transition metal-based material, the exploration of LDHs in EMW absorption has just begun.

MOF-derived nanoporous carbon/Co/Co3O4/CNTs/RGO composite with hierarchical structure as a high-efficiency electromagnetic wave absorber

Lightweight and high-efficiency electromagnetic (EM) wave absorption are two key factors in the research of new-type absorbers, which could be obtained by regulating the component, structure, or suitable impedance matching. In this paper, a nanoporous carbon/Co/Co3O4/carbon nanotubes (CNTs)/reduced graphene oxide (RGO) composite with polyhedral structure was prepared by high-temperature pyrolysis of Co-based zeolitic imidazolate frameworks (ZIF 67). The carbon/Co/Co3O4/CNTs/RGO composite was composed of carbon polyhedrons, in which Co and Co3O4 particles were encapsulated by carbon polyhedrons and CNTs. With a filler ratio of 20 wt%, this absorber displayed the highest reflection loss (RL) of −59.2 dB at 11.2 GHz with 2.5 mm thickness and the absorption bandwidth (RL exceeding −10 dB) of 5.7 GHz (12.3–18 GHz) with a thickness of only 2 mm. The outstanding microwave absorption performance of this material results from proper impedance matching, synergistic effect, enhanced interfacial polarizations and interior cavities. This strategy may provide guidance for the manufacture of new-type absorbers with high-efficiency characteristics.

Insight of S, N co-doped graphene aerogel (double reduction)/cobalt (Ⅱ)-substituted α-Keggin-type polyoxometalate nanocomposites with synergistically enhanced impedance matching and energy conservation performance

Exploring new types of absorbing materials has always been the focus and hot spot of stealth research. As we all know, the best conductivity of absorbing materials is generally in the range of semiconductor. Polyoxometalate is a kind of metal oxygen cluster with semiconductor properties and a good electron acceptor, but there is little research on its absorption property. In this work, we synthesized S, N co-doped graphene aerogel (secondary reduction by ascorbic acid)/cobalt (Ⅱ)-substituted α-Keggin-type polyoxometalate (SNGA(Vc)/α-SiW11Co) nanocomposites through some facile routes. The graphene aerogel and polyoxometalate could analogously play the role of alkali and acid, respectively, attracting each other through electrostatic interaction, in addition to hydrogen bonding (N–H- … O, O–H- … O). By changing the types of element doped graphene aerogels and reduction degree, it could regulate the conductivity and affect the polarization relaxation capacity of SNGA(Vc)/α-SiW11Co nanocomposites. With a filling rate of 1:2.5 in paraffin matrix, the maximum reflection loss was up to −67.9 dB at 17.3 GHz and 1.6 mm. There was also another strong absorption peak value of −63.7 dB at 3.5 mm and 6.9 GHz. The absorption bandwidths with the RL value lower than −10 and −20 dB remarkably reached as strong as 14.1 and 13.4 GHz when the thickness range was 1.5–5 mm, respectively, meaning the super electromagnetic wave absorption ability of SNGA(Vc)/α-SiW11Co nanocomposites. This study demonstrates that the polyoxometalate composite materials can become a novel idea for designing high-efficiency electromagnetic wave absorbers.

One-Pot Hydrothermal Synthesis of MWCNT/ZrO2 Composites for Enhancing Electromagnetic Wave Absorption Performance

Electromagnetic (EM) wave absorption materials have drawn a lot of attention because they can effectively reduce EM wave pollution from electronic equipment. In this work, we combined ZrO2 nanoparticles with multi-walled carbon nanotubes (MWCNTs) and explored applications of MWCNT/ZrO2 composites in EM wave absorbing field. ZrO2 nanoparticles with a high crystalline were synthesized by one-step hydrothermal method. Adding MWCNTs in this hydrothermal process, ZrO2 nanoparticles aggregated together to form uneven lumps and wraps on MWCNTs surfaces. MWCNTs improved the conductivity loss and electron polarization capability of composites. The minimum reflection loss (RL) of MWCNT/ZrO2 composites reached [Formula: see text]39.73 dB at a thickness of 2[Formula: see text]mm. Such excellent EM wave absorption properties are attributed to the dielectric loss, dipole polarizations and interfacial polarizations. This composite can be a promising candidate as high efficiency EM wave absorption material and used for commercial production because of the simple synthesis methods.

Engineering compositions and hierarchical yolk-shell structures of NiCo/GC/NPC nanocomposites with excellent electromagnetic wave absorption properties

Designable microstructure was crucial for fabricating electromagnetic wave (EMW) absorbing materials. Herein, NiCo nanoparticles/graphitic carbon/nanoporous carbon (NiCo/GC/NPC) core–shell nanocomposites with novel hierarchical double yolk-shell structure were synthesized from metal-organic frameworks by a facile process. The yolk-shell nanoporous core–shell structure of the NiCo/GC/NPC nanocomposites was expertly tuned by regulating the composition of the Ni and Co elements, leading to the engineering relaxation polarization, conductive loss, magnetic resonance and multiple scatterings and reflections. The Ni1Co2/GC/NPC nanocomposite exhibited a minimum reflection loss (RLmin) value of −52.2 dB and a broad effective absorbing bandwidth (EAB) of 7.2 GHz (from 10.8 to 18 GHz) for RL < −10 dB with a thin thickness of 2.1 mm. The outstanding absorbing performance was ascribed to the optimized nanostructure which integrated the yolk-shell configuration, nanoporous structure and core–shell architecture, which brought in higher tunable dielectric and magnetic loss with the good impedance matching. This work provides a facile paradigm for the design and fabrication of the yolk-shell nanoporous core–shell structure for light weight and high-efficiency EMW absorbers.

Facile One-Pot Solvothermal Synthesis of the RGO/MWCNT/Fe3O4 Hybrids for Microwave Absorption.

How to effectively regulate the electromagnetic parameters of magnetic composites to achieve better microwave absorption (MA) performances is still a serious challenge. Herein, we constructed nanocomposites composed of magnetic constituents and carbon materials to obtain high-efficiency electromagnetic wave absorbers. Self-assembled, multi-interfacial, and porous RGO/MWCNT/Fe3O4 hybrids (GMFs) were synthesized via in situ one-pot solvothermal method. The growth mechanism of the GMFs would be that the defects on reduced graphene oxide (RGO) provide sites for the crystallization of Fe3O4. Also, the RGO and Fe3O4 were further linked by the cross-connection of multiwalled carbon nanotubes (MWCNTs), which acted as a bridge. The MA mechanism of GMFs was studied while considering the synergistic effects between the three components (RGO, MWCNT, and raspberry-shaped Fe3O4) and their multi-interfacial and porous structure. Also, the MA performance of the GMFs was conducted. The GMFs exhibited a maximum reflection loss (RL) value of −61.29 dB at 10.48 GHz with a thickness of 2.6 mm when the contents of RGO and MWCNT were 6.3 and 1.3 wt %, respectively. The RL values (≤−10 dB) were observed to be in the range of 8.96–12.32 GHz, and the effective microwave absorption bandwidth was tunable from 3.52 to 18 GHz by changing the sample thickness. The results revealed that the multi-interfacial and porous structure of the GMFs is beneficial to MA performance by inducing multiscatterings. Since no toxic solvents were used, this method is environmentally friendly and has potential for large-scale production. The prepared GMFs may have a wide range of applications in MA materials against electromagnetic interference pollution.