High-performance Microwave Absorption Materials Research Articles

Facile synthesis of 2D MoS2/reduced graphene oxide hybrids with excellent microwave absorption

High-performance microwave absorption materials with tunable electromagnetic properties have long been the goal of researchers. It is still a challenge to achieve broad band absorption and lightweight performance by simply optimizing the chemical composition of absorbers. Molybdenum disulfide (MoS2) belongs to the two-dimensional transition metal disulfide with a layered structure similar to graphene. In this work, two-dimensional MoS2/reduced graphene oxide (MS/RGO) hybrids have been constructed through a convenient self-assembled hydrothermal method, in which MoS2 ultrathin nanosheets in-situ grow uniformly on the surface of RGO, constructing a unique hierarchical microstructure. Electromagnetic parameter measurements display that the dielectric behaviors of MS/RGO composites are optimized via changing the content of RGO, and meanwhile the superior microwave absorption properties are achieved with the filler-loading ratio of only 20 wt%. The widest effective absorption bandwidths (RL<−10 dB) of 5.68 GHz (12.32–18 GHz) and 6.32 GHz (11.20–17.52 GHz) are observed at a thickness of 2.0 mm for MS/RGO-10 and MS/RGO-15, respectively. When the thickness is raised to 5.0 mm, the reflection loss value of MS/RGO-10 composites reaches the minimum value of − 39.8 dB at 4.96 GHz. The improved performance can be explained by the strong interfacial polarization loss due to abundant heterogeneous interfaces, defect dipole polarization, conduction loss, and multiple reflections and scattering. The results indicate that the light-weight MS/RGO composite is considered as a promising candidate for high-performance microwave absorbers with an adequate absorption bandwidth.

Morphology engineering of defective graphene for microwave absorption

Graphene with abundant defects has been considered as the most lightweight electromagnetic functional materials. Although important, the dominant electromagnetic response of defective graphene with diverse morphologies is rarely the focus of existing research. Herein, the defective graphene with two-dimensional planar structure (2D-ps) and three-dimensional continuous network (3D-cn) morphologies were dexterously designed with 2D mixing and 3D filled systems of polymeric matrix. A comparison between the topologies of defective graphene-based nanofillers and the microwave attenuation behaviors was examined. Defective graphene with 3D-cn morphology can achieve ultralow filling content and broadband absorption, which is attributed to the presence of numerous pore structures that promote impedance matching, induce continuous conduction loss and provide multiple reflection and scattering sites for electromagnetic wave attenuation. Comparatively, by virtue of the increased filling content of 2D-ps, the dielectric losses primarily originate from the dielectric genes, including aggregation-induced-charge transport, abundant defect and dipole polarization, resulting in good microwave absorption at low thickness and low frequency. Therefore, this work provides a pioneering insight into morphology engineering of defective graphene microwave absorbers, and it will guide future exploration of customizing high-performance microwave absorption materials based on graphene-based low-dimensional building blocks.

Rational design of hollow microspheres@Ba0.5Sr0.5Fe12O19/PANI for lightweight high-performance microwave absorption materials

Rational design of hollow microspheres@Ba0.5Sr0.5Fe12O19/PANI for lightweight high-performance microwave absorption materials

Construct of CoZnO/CSP biomass-derived carbon composites with broad effective absorption bandwidth of 7.2 GHz and excellent microwave absorption performance

Biomass-carbon materials have excellent electromagnetic wave attenuation properties, which is one of the essential factors for developing ultra-thin matched-thickness, and high-performance microwave absorption materials. This study reports a two-step procedure consisting of carbonization and subsequent in-situ growth for preparing a wrinkle-like multilayer biomass-derived composites with magnetic Co particles and ZnO particles (CoZnO/C-X). The synergistic effect of a wrinkle-like multilayer structure and Co and ZnO particles, as well as the existence of many heterogeneous interfaces in the composites structure, and efficiently creates multiple scattering and reflections, which gives the composites the strong microwave absorption properties. The minimum reflection loss value (RLmin) of CoZnO/C-X reaches − 54.90 dB with a thickness of 1.8 mm, and the effective absorption bandwidth (lower than − 10 dB) is 7.2 GHz covering from 10.8 GHz to18.0 GHz with matching thickness of 2.0 mm. Furthermore, the reasonable dielectric/magnetic losses, optimized impedance matching and enhanced polarization loss play an indispensable role among improving microwave absorption performance. Thus, this result provides a good potential method for preparation of magnetic particle/metal oxide/biomass-derived carbon microwave absorbing structural materials.

Construction of multi-dimensional NiCo/C/CNT/rGO aerogel by MOF derivative for efficient microwave absorption

The development of high-performance microwave absorption materials is currently imperative in order to solve the problem of electromagnetic pollution. Herein, we successfully obtained a multi-dimensional graphene-based aerogel (NiCo/C/CNT/rGO aerogel) decorated with one-dimensional carbon nanotubes (CNTs) and metal-organic framework (MOF) derivatives. The introduction of rGO aerogel significantly modifies the phase composition (NiCo/C/CNT and rGO) and hierarchical structure (1D CNT, 3D NiCo/C/CNT and rGO aerogel) of the composite, resulting in a multi-dimensional gradient, defects, heterogeneous interfaces, and superior microwave absorption properties. The optimum electromagnetic wave absorption performance of −58.8 dB is achieved at a filler loading of 20 wt%, with a thickness of 1.8 mm and an effective absorption bandwidth of 7.6 GHz, covering the entire Ku-band. The excellent electromagnetic wave absorption performance can be attributed to the synergistic effect of impedance matching, electromagnetic attenuation capability, unique multi-dimensional porous structure, abundant defects and interfaces. In summary, the present work provides a novel approach for the synthesis of multi-dimensional lightweight magnetic/dielectric microwave absorbers.

Hierarchical graphene@MXene composite foam modified with flower-shaped FeS for efficient and broadband electromagnetic absorption

• Ultralight magnetic composite foam with hierarchical structure is fabricated. • Loading of MXene/FeS on rGO promotes the formation of hierarchical impedance in foam. • Hierarchical impedance structure facilitates the entrance and dissipation of EMW. • Optimization of impedance structure improves absorption capacity and bandwidth. Developing high-performance broadband microwave absorption material becomes an urgent concern in the field of electromagnetic protection. In this work, an ultralight magnetic composite foam was constructed by electrostatic self-assembly of MXene on the surface of graphene skeletons, and subsequent hydrothermal anchoring of flower-shaped FeS clusters. Under the synergistic effect of MXene coating increasing conductive loss and FeS clusters improving magnetic loss, the rational construction of hierarchical impedance structure in foam can effectively promote the entrance and consumption of more incident electromagnetic waves. The minimum reflection loss (RL min ) reaches –47.17 dB at a thickness of 4.78 mm, and the corresponding effective absorption bandwidth (EAB) is up to 6.15 GHz. More importantly, the microwave absorption performance of composite foam can be further optimized by controlling the loading of MXene and thermal treatment at a low temperature. The maximum of EAB for GMF-300 can be extended to an unprecedented value of 11.20 GHz (covering 6.10–17.30 GHz).

Recent progress in TiO2-based microwave absorption materials.

It is particularly important to develop high-performance microwave absorption (MA) materials to remediate the increasingly serious electromagnetic pollution. Recently, titanium dioxide-based (TiO2-based) composites have become a research hotspot owing to their light weight and synergy loss mechanism. In this study, significant research progress in TiO2-based complex-phase microwave absorption materials is reviewed, which involves carbon components, magnetic materials, polymers and so on. First, the research background and limitations of TiO2-based composites are discussed. The design principles for microwave absorption materials are elaborated in the next section. More importantly, TiO2-based complex-phase materials with multi-loss mechanisms are analyzed and summarized in this review. Finally, the conclusions and prospectives are presented, which provide a reference for the understanding of TiO2-based MA materials.

Hierarchical dandelion-like CoS2 hollow microspheres: self-assembly and controllable microwave absorption performance.

The emerging electromagnetic radiation and interference problems have promoted the rapid development of microwave absorption materials (MAMs). However, it remains a severe challenge to construct high-performance microwave absorption materials with broadband, lightweight and corrosion resistance within low filling contents. Herein, hierarchical dandelion-like CoS2 hollow microspheres were reasonably constructed via a solvothermal-hydrothermal etching-in situ vulcanization process. The structure morphology, composition and electromagnetic performance of all samples have been thoroughly tested. The research results demonstrated that the structure morphology of the prepared samples with a volume ratio of 1 : 1 between ethanol and H2O remained intact without serious damage. Notably, the as-obtained hierarchical dandelion-like CoS2 hollow microspheres (25 wt%) exhibited excellent microwave absorption capacity with a minimum reflection loss (RLmin) of -47.3 dB and the corresponding effective absorption bandwidth (EAB) of 8.4 GHz at 3.3 mm. Moreover, the broadest effective absorption bandwidth (EAB, RL < -10 dB) reached 9.0 GHz (9.0-18.0 GHz) at the matching thickness of 3.2 mm. The unparalleled multiple features including hierarchical hollow structure, tunable complex permittivity as well as the enhanced impedance matching endowed CoS2 great promise as high-performance microwave absorbers for solving the problem of electromagnetic pollution.

Enhanced Electromagnetic Wave Absorption of SiOC/Porous Carbon Composites.

Carbon-based materials have been widely explored as electromagnetic (EM) wave absorbing materials with specific surface areas and low density. Herein, novel porous carbon/SiOC ceramic composites materials (porous C/sp-SiOC) were prepared from the binary mixture, which used the low cost pitch as carbon resource and the polysilylacetylene (PSA) as SiOC ceramic precursor. With the melt-blending-phase separation route, the PSA resin formed micro-spheres in the pitch. Then, numerous SiOC ceramic micro-spheres were generated in porous carbon matrices during the pyrolysis process. By changing the percent of SiOC, the microstructure and wave absorption of porous C/sp-SiOC composites could be adjusted. The synergistic effect of the unique structure, the strong interfacial polarization, and the optimized impedance matching properties contributed to the excellent absorption performance of porous C/sp-SiOC composites. The minimum reflection loss for porous C/sp-SiOC absorber reached -56.85 dB, and the widest effective bandwidth was more than 4 GHz with a thickness of only 1.39 mm. This presented research provides an innovative and practical approach to developing high-performance porous carbon-based microwave absorption materials from green chemistry.

Decoration of worm-like Cu2S particles on CuCo2S4 micro-spheres: An effective strategy to improve the electromagnetic dissipation feature

Civilization can be shielded from the dangerous electromagnetic spectrum by using microwave absorption materials, however, absorbing electromagnetic radiation with thin thickness and high bandwidth remains a challenge, especially at scales that are significant. Herein, we propose a novel architecture where worm-like Cu2S particles are decorating CuCo2S4 micro-spheres were decorated, and this method is thought to be a successful one for enhancing the created nanocomposite's ability to dissipate electromagnetic radiation. Changing the filler loading percentage allows the nanohybrids' electromagnetic characteristics and microwave dissipation effectiveness to be efficiently changed. This leads to the creation of ultra-bandwidth absorbers with thin thickness, which are then tested using waveguide and free-space techniques. The sample with a thickness of 1.4 mm has a maximum reflection loss of −18 dB and a maximum bandwidth of 3.6 GHz. The hetero-structures, multi-interfaces, and multiple relaxations phenomena, as well as the combined effects of the two components, are credited with the superior microwave absorption performance compared with the state-of-the-art. This finding demonstrates that CuCo2S4/Cu2S nanohybrids pave the way for the development of future high-performance microwave absorption materials.

Ti3C2Tx MXene@NiFe layered double hydroxide derived multiple interfacial composites with efficient microwave absorption

High-performance microwave absorption materials are considered to be an effective solution to the increasing electromagnetic pollution. In this work, Ti3C2Tx MXene@NiFe-layered double hydroxide (NiFe-LDH) derived multi-interfacial FeNi3/TiN@nitrogen-doped carbon (NC)@magnetic multiwalled carbon nanotube composites were prepared by a hydrothermal process and subsequent carbothermal reduction. The phase compositions, morphology, defects and electromagnetic parameters of the composites can be regulated by the thermal treatment temperature. The reflection loss value of the composite with a thickness of only 1.6 mm can reach − 43.75 dB when the heat treatment temperature is 900 °C, and the effective absorption bandwidth is 5.5 GHz with a thickness of 2.12 mm when the heat treatment temperature is 700 °C. The synergistic effects among the associated dielectric loss, magnetic loss and the impedance matching of the samples are also systematically investigated. This work provides a new perspective and an effective approach for acquiring MXene hybrids derived high-performance microwave absorbing materials.

MOF-derived core-shell Co9S8 @MoS2 nanocubes anchored on RGO to construct heterostructure for high-efficiency microwave attenuation

Elegant material construction to realize high-efficiency microwave absorption with low filler loading is in strong demand yet remains challenging. Here we combine a self-assembly method followed by pyrolysis to fabricate core-shell Co9S8 @MoS2 nanocubes, which were uniformly anchored on reduced graphene oxide nanosheets (A-G/Co9S8 @MoS2) to form hierarchical heterostructures. The heterostructure was deliberately designated via chemical etching of in situ formed Co9S8 derived from ZIF-67 and decoration of flower-like MoS2 nanosheets. Owing to its synergic effect in compositions and well-designed heterostructure, the product A-G/Co9S8 @MoS2 exhibits excellent microwave absorption performance with low loading content. A minimum reflection loss of − 55.13 dB and effective absorption bandwidth of 6.61 GHz with filler loading of only 8 wt% was achieved, contributed by the good impedance matching and dual loss mechanism. This work provides a new pathway for designing low-filler loading high-performance microwave absorption materials.

Microstructure optimization of core@shell structured MSe2/FeSe2@MoSe2 (M = Co, Ni) flower-like multicomponent nanocomposites towards high-efficiency microwave absorption

• Core@shell structured M Se 2 /FeSe 2 @MoSe 2 ( M =Co, Ni) flower-like MCNCs were selectively synthesize through a simple route. • The obtained core@shell structured MCNCs with the different MoSe 2 contents and flower-like morphologies could be tuned. • The obtained M Se 2 /FeSe 2 @MoSe 2 ( M =Co, Ni) flower-like MCNCs displayed very outstanding comprehensive MAPs. • Our findings provided a new and effective pathway to develop the strong wideband MAs. In this work, we put forward a scheme to exquisitely design and selectively synthesize the core@shell structured M Se 2 /FeSe 2 @MoSe 2 ( M = Co, Ni) flower-like multicomponent nanocomposites (MCNCs) through a simple two-step hydrothermal reaction on the surfaces of M Fe 2 O 4 nanospheres with the certain amounts of Mo and Se sources. With increasing the amounts of Mo and Se sources, the obtained core@shell structured M Se 2 /FeSe 2 @MoSe 2 ( M = Co, Ni) MCNCs with the enhanced content of MoSe 2 and improved flower-like geometry morphology could be produced on a large scale. The obtained results revealed that the as-prepared samples displayed improved comprehensive microwave absorption properties (CMAPs) with the increased amounts of Mo and Se sources. The as-prepared CoSe 2 /FeSe 2 @MoSe 2 and NiSe 2 /FeSe 2 @MoSe 2 MCNCs with the well-defined flower-like morphology could simultaneously present the outstanding CMAPs in terms of strong absorption capability, wide absorption bandwidth, and thin matching thicknesses, which mainly originated from the conduction loss and flower-like geometry morphology. Therefore, the findings not only develop the very desirable candidates for high-performance microwave absorption materials but also pave a new way for optimizing the CMAPs through tailoring morphology engineering.

Enhanced heat conductance and microwave absorption of 2D laminated Ti3C2Tx MXene microflakes via steering surface, defects, and interlayer spacing

In this paper, 2D laminated Ti3C2Tx MXene was successfully synthesized via etching the Al layer on Ti3AlC2 precursors in a one-step hydrothermal reaction. Controlling the etching time (t) handily adjusted the defects, surface groups, interlayer spacing, and surface oxide layer of laminated Ti3C2Tx MXene. With the prolonged etching time, the electrical conductivity and heat conductance changed in an inverted U-type. Moreover, the permittivity and low-frequency attenuation ability of Ti3C2Tx were enhanced, but the impedance matching decreased. The laminated Ti3C2Tx MXene harvest a maximal effective bandwidth of 6.32 GHz (RL ≤ −10 dB, 1.4 mm in thickness) with a maximal absorption of − 33.37 dB at t = 72 h and the optimal heat conductance of 2.746 W/(m·K) at t = 12 h. The outstanding comprehensive properties are owing to the synergistic effects of interface, defect/dipole, orientation, and crossing polarizations, caused by 2D laminated structure with appropriate layer spacing, surface functional groups, and defects. Consequent upon this fact, our strategies offer some significant insights for designing high-performance microwave absorption and heat conductance materials.

Fe@Fe3C Core-Shell Nanoparticles Embedded in Polyvinyl Alcohol-Derived Porous Carbon toward Light and High-Performance Microwave Absorption

High-performance microwave absorbents play a key role in information technology field. In this work, excellent microwave absorption property was achieved via embedded Fe@Fe3C core–shell nanoparticles in polyvinyl alcohol-derived porous carbon matrix. The results indicate that the microwave absorption performance will be greatly enhanced due to the interface between the nanoparticles and matrix, as well as the core–shell and porous structure, increase the energy consumption capacity via dipole polarization, interface loss and the multiple reflection/scattering. The maximum reflection loss (RLmax) reaches −56.88 dB at 11.3 GHz with the thickness of 2.11 mm, and the effective absorption bandwidth (EAB, RL<−10 dB) can get up to 5.2 GHz (from 12.9 to 18 GHz) with the thickness of 1.64 mm. Moreover, due to the low density of the porous carbon matrix, the total weight of the absorbents can be greatly induced, which provides an efficient way for lightweight and high-performance microwave absorption materials design.

Recent progress of polyaniline-based composites in the field of microwave absorption

Electromagnetic waves pollution as one of the major pollutions, has seriously endangered the human health and the normal use of electronic equipments. The development of high-performance microwave absorption (MA) materials containing wide absorption bandwidth, strong absorption capacity and light weight has become imminent. Due to excellent electrical conductivity, corrosion resistance, and unique doping mechanism, polyaniline (PANI) is expected to be a highly efficient microwave absorber. However, the lack of magnetic loss and multi-interface polarization of single-component PANI makes it difficult to meet practical applications. Therefore, compounding PANI with other lossy materials is used to improve its MA performance. This paper reviews the research background and the mechanism of PANI-based MA materials. Subsequently, the research progress of PANI/carbon composites, PANI/ferrite composites, PANI/natural composites and multicomponent PANI-based composites is introduced. The challenges and the prospects for the development of PANI-based composites in MA are presented, and the directions and the priorities for future research are pointed out.

Controllable Synthesis of Hierarchical Dendrite-Like Iron-Based Hybrids with Boosting Microwave Absorption Performance

Fabricating high-performance microwave absorption materials with excellent attenuation property covering low frequency ranges are urgently needed for applications in our daily life. Herein, we put forward the controllable synthesis of hierarchical dendrite-like iron-carbon hybrids (Fe-C based hybrids) through three steps, including the hydrothermal method, chemical vapor deposition strategy and hydrogen reduction using K3[Fe(CN)6] and C2H2 as Fe and C source, respectively. Due to the existence of interface polarization effect, natural resonance, and exchange resonance generated from Fe-C based hybrids, the microwave absorption property in low frequency bands of the as-fabricated Fe-C based hybrids are growing as the filler loading increases. The Fe-C based hybrids achieved the minimum reflection loss value (RLmin) at 2.95 GHz as low as -31.73 dB at 4.5 mm, and the effective absorption bandwidth can reach up to 9.19 GHz in the range of thickness from 1.5 to 5.0 mm, covering the entire L, S, C, and X-band frequency bands. The novel structure design provides a facile and meaningful strategy for fabricating two-dimensional hierarchical dendrite-like Fe-C based hybrids as high-performance microwave absorbers.

Hierarchical CoNi alloys toward microwave absorption application: Chain-like versus particle-like

CoNi alloys are well known as excellent magnetic microwave absorption materials, but their various structures greatly influence electromagnetic properties, especially chains versus particles. Hierarchical CoNi chains were prepared using the solvothermal method in conjunction with an external magnetic field, and hierarchical CoNi particles were obtained in the absence of the magnetic field. Changing the reaction time from 6 to 12 h can change the surface structures of hierarchical CoNi alloys, as seen in the SEM images. The lattice parameters of samples are determined by XRD results, which include crystalline structures, lattice constants, mean crystallite sizes, and internal strain. The investigation of magnetic properties indicates that CoNi chains possess a stronger saturation magnetization and higher coercivity than CoNi particles as a result of their higher aspect ratios and larger crystalline sizes. Furthermore, CoNi chains have a higher microwave absorption capacity than CoNi particles, with a minimum reflection loss value of −42.113 dB (16.5 GHz) and an effective absorption bandwidth of 3.5 GHz (13–16.5 GHz). Conductive loss, defect-induced polarization relaxation, eddy current effect, exchange resonance, N é el relaxations, multiple reflections, and scatterings all contribute to the excellent microwave absorption performance of the CoNi chains. This research establishes that a chain-like structure outperforms a particle-like structure for hierarchical CoNi alloys as microwave absorbers, and it will provide clear guidance for designing high-performance magnetic microwave absorption materials.

Simultaneously enhancing mechanical and microwave absorption properties of Cf/SiC composites via SiC nanowires additions

Cf/SiC composite is an excellent structural and functional material, silicon carbide nanowires (SiCnws) are not only a toughening material but also a great application in the field of microwave absorption. In this study, SiCnws are grown on the surface of carbon fiber (Cf) by polymer impregnation and pyrolysis, and the SiC matrix was prepared by chemical vapor osmosis method. The SiCnws are introduced to enhance the mechanical and microwave absorption properties simultaneously. After 3 impregnations, the flexural strength of the composite was 107.35 ± 10 MPa. When the thickness is 1.86 mm, the minimum reflection loss value is −41.08 dB, and the effective absorption bandwidth (RL ≤ −10 dB) is 3.86 GHz. Furthermore, the microwave absorption mechanism of the material is discussed. This work provides a new method to prepare lightweight, stable and high-performance microwave absorption materials, and these materials are expected to be used in high temperature environments.

Nickel/porous carbon derived from rice husk with high microwave absorption performance

BHPC (biomass hierarchical porous carbon) is a new microwave absorption material with extraordinarily low density, excellent dielectric loss, and a low environmental impact. In this paper, a Ni/BHPC composite is introduced, which were fabricated using a simple electroless plating method. When the NiSO4 concentration is changed, the electromagnetic characteristics and absorption performance are optimized. The Ni/BHPC composite material exhibits excellent absorption characteristics at a NiSO4 concentration of 0.2 mol/L. With a thickness of 2.7 mm, the RLmin is −58.504 dB at 10.741 GHz. In the frequency range 8.221–12.4 GHz, with a thickness of 2.9 mm, this reflection loss (RL) is less than −10 dB. These results indicate that incorporating Ni particles into the BHPC enhances its wave absorption efficiency. The research contributes to develop high-performance porous carbon microwave absorption materials from biomass.