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Microwave absorption (MA) materials are widely used in military and civilian applications to solve electromagnetic wave absorption and attenuation problems. The generation of high-performance materials containing extensive absorption frequency, strong absorption capacity and light weight has become a research focus in the field of MA. Magnetic materials have a wide range of applications due to their intrinsic ferromagnetic resonance absorption capacity. In addition to the inherent electromagnetic properties, the microstructure and morphology of the absorption material also have important influences on the electromagnetic wave absorption properties. One-dimensional (1D) nanostructure is considered to be beneficial microscopic morphology due to their unique shape anisotropy. The high aspect ratio is conducive to electron conduction and further increases the conduction loss capability. This review introduced the research progress of 1D magnetic nanomaterials in MA and categorized them from the viewpoint of preparation methods. Challenges and prospects were proposed toward the development of 1D magnetic nanomaterials in MA, which indicated the directions and priorities for future research. [ABSTRACT FROM AUTHOR]

[Display omitted] Advanced microwave absorption (MA) materials have attracted widespread attention to meet the challenges of electromagnetic (EM) pollution. Herein, MgFe 2 O 4 /MgO/C fibers were successfully prepared via electrospinning technology and carbonization, and their surfaces were coated by MoS 2 via hydrothermal method. The EM wave absorption performance of composites was enhanced due to the introduction of MoS 2. The results showed that the EM wave absorption performance of MgFe 2 O 4 /MgO/C could not meet the requirements due to low dielectric loss and poor impedance matching. The performance of the composites was improved after coating of MoS 2 , which showed the strong wave absorption capability and the broad absorption bandwidth. The optimal reflection loss (RL) is −56.94 dB at 9.5 GHz and the effective absorption bandwidth is 3.9 GHz (8.08–11.98 GHz) with a thickness of 2.7 mm. The excellent MA performance can be mainly attributed to excellent synergistic effect between MgFe 2 O 4 /MgO/C and MoS 2. Furthermore, MoS 2 also contributes to dielectric loss and ideal impedance matching. MgFe 2 O 4 /MgO/C@MoS 2 composites may be utilized for lightweight and high-efficient MA materials. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, one-dimensional (1D) ZnFe 2 O 4 @carbon@MoS 2 /FeS 2 composites were synthesized by hydrothermal method, magnetic-field-induced distillation-precipitation polymerization and high-temperature carbonization. The structure, morphology, composition, magnetic performance and electromagnetic (EM) wave absorbing properties of the composites were systematically studied. The composites show strong microwave absorption (MA) capacity with a minimum reflection loss (RL min) value of −52.5 dB at 13.2 GHz, and have an effective absorption frequency range of 10.10–15.08 GHz with a bandwidth of 4.98 GHz when the thickness is 2.23 mm. It is expected that as-synthesized 1D ZnFe 2 O 4 @carbon@MoS 2 /FeS 2 composites can be a promising EM wave absorption material. [ABSTRACT FROM AUTHOR]

Designing one-dimensional (1D) magnetic-carbon composites microwave absorbers is a promising strategy that can meet the current demand for high-performance microwave absorption (MA) materials. In this work, hierarchical structured Fe 3 O 4 /Fe@C@MoS 2 nanofibers were successfully obtained via a simple three-step method. 1D Fe 3 O 4 /Fe@C nanofibers were fabricated through electrospinning technology and in-situ polymerization followed by carbonization and reduction in H 2 /N 2 atmosphere. MoS 2 nanosheets grew irregularly on the surface of 1D Fe 3 O 4 /Fe@C nanofibers to form the flower-like structure. The morphology, composition and magnetism of samples were systematically investigated. Furthermore, electromagnetic characteristics and MA properties of Fe 3 O 4 /Fe@C nanofibers and Fe 3 O 4 /Fe@C@MoS 2 nanofibers were compared. The minimum reflection loss (RL min) of Fe 3 O 4 /Fe@C@MoS 2 nanofibers could reach −53.79 dB at 11.12 GHz and the corresponding absorption bandwidth (RL < -10 dB) of 4.4 GHz was achieved at the absorber thickness of 2.24 mm. This work combines electrospinning technology with traditional chemical synthesis to prepare a novel 1D core-shell microwave absorber, which provides some inspiration for preparing MA material in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

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. • Representative polyaniline-based microwave absorbers are introduced. • The mechanism of polyaniline-based microwave absorbers is elaborated and summarized. • The related modification strategies of polyaniline-based microwave absorbers are classified. • The facing challenges and further opportunities of polyaniline-based microwave absorbers are overviewed. [ABSTRACT FROM AUTHOR]

[Display omitted] Herein, coralloid core-shell structure NiS/Ni 3 S 4 @PPy@MoS 2 nanowires were elaborately designed and successfully synthesized through a three-step route to obtain exceptional microwave absorption (MA) properties. Ni nanowires were first fabricated, and then used as the substrate to be coated with a layer of PPy. Ni chalcogenides were obtained by using Ni nanowire as sacrificial templates while growing MoS 2 nanorods by hydrothermal method. Both the one-dimensional (1D) core-shell structure and the coralloid surface generated by MoS 2 nanorods were beneficial for the attenuation of microwaves. After investigating the electromagnetic properties of different loading content absorbers (30 wt.%, 40 wt.% and 50 wt.%), it is found that the 50 wt.% loading absorber has the optimal MA performance. The minimum reflection loss (RL min) value can reach −51.29 dB at 10.1 GHz with a thickness of 2.29 mm, and the corresponding effective absorption bandwidth (EAB, RL < −10 dB) can be up to 3.24 GHz. This research provides a reference for exploiting novel high-efficient 1D absorbers in the field of MA. [ABSTRACT FROM AUTHOR]

As important functional materials for absorbing and attenuating incident electromagnetic waves, microwave absorption (MA) materials have found a wide range of applications in civil and military fields. In addition to the study of the compositions, the structural design of the MA materials is also a research hotspot in the field. Among the various structures, the one-dimensional (1D) structure has drawn wide attention because of the unique shape anisotropy and spatial confinement effect. Electrospinning technology has become one of the main ways to prepare continuous 1D micro-nano fibers due to the advantages of many types of spinnable materials, low spinning cost, and high controllability of process parameters. This review involves an introduction and a classification of the research progresses achieved in electrospinning technology concerning MA nanofibers from the perspective of compositions, as well as the list of their minimum reflection loss (RL min) and effective absorption bandwidth (EAB). [ABSTRACT FROM AUTHOR]

One-dimensional (1D) ZnFe 2 O 4 @SiO 2 (ZS) nanochains were prepared with Stöber method under external magnetic field. Then, 1D ZS nanochains were covered with a uniform polydopamine (PDA) shell, and the pyrolysis process was completed to obtain 1D ZnFe 2 O 4 @SiO 2 @C (ZSC) nanochains. Finally, 1D flower-like ZnFe 2 O 4 @SiO 2 @C@NiCo 2 O 4 (ZSCNC) nanochains were fabricated through a simple hydrothermal method. The carbon layer with strong dielectric loss enabled the 1D ZSC nanochains to achieve an ultra-wide effective absorption bandwidth (EAB) of 6.22 GHz. Compared with the above nanochains, the 1D ZSCNC nanochains showed more excellent microwave absorption (MA) properties because of the unique 1D flower-like architectures having large surfaces and multiple interfaces. The sample loaded with 30 wt% 1D flower-like ZSCNC nanochains showed strong MA performances with a minimum reflection loss (RL) value of −54.29 dB (11.14 GHz) and an EAB of 5.66 GHz (11.94–17.60 GHz) at the thickness of 2.39 mm. The 1D flower-like ZSCNC nanochains with strong absorption, broad absorption bandwidth (almost the entire Ku band) and thin layer has a good application prospect for the absorption of electromagnetic waves in Ku band. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flower-like surface Ni@Co 3 O 4 /RGO composites were designed and fabricated. • The possible microwave absorption mechanism was demonstrated and illustrated. • The optimal reflection loss value of −60.0 dB can be obtained. Novel composite microwave absorption (MA) materials with multiple loss mechanism have attracted considerable attention. In this work, flower-like surface Ni@Co 3 O 4 nanowires were designed and fabricated through chemical reduction method induced by magnetic field, followed by in-situ polymerization, low temperature oil bath and thermal annealing. Then, the Ni@Co 3 O 4 /RGO composites were prepared through a hydrothermal reaction of the Ni@Co 3 O 4 nanowires and graphene oxide suspension. The electromagnetic properties of different loading content samples (15 wt%, 25 wt% and 35 wt%) were measured to investigate the influence of loading content on the MA performance. For the 35 wt% loading sample, the minimum reflection loss (RL min) value of −60.0 dB was determined at the thickness of 2.3 mm, and the maximum effective absorption bandwidth (EAB, RL < −10 dB) of 4.62 GHz can be achieved when the thickness is 1.6 mm. This research provides a reference for exploiting high-efficient flower-like surface magnetic-dielectric composites in the field of MA. [ABSTRACT FROM AUTHOR]

Hierarchical structured ZnFe 2 O 4 @SiO 2 @C@NiO/reduced graphene oxide (ZSCN/RGO) composites were designed and fabricated via a multi-step route. One-dimensional (1D) ZnFe 2 O 4 @SiO 2 nanochains were fabricated through magnetic-field-induced stöber method. ZnFe 2 O 4 @SiO 2 @phenolic resin nanochains were synthesized through in-situ polymerization and then after high-temperature carbonization ZnFe 2 O 4 @SiO 2 @C (ZSC) nanochains were obtained. 1D ZSCN nanochains with flower-like surface were formed after NiO nanosheets grew irregularly on the surface. Finally, ZSCN/RGO composites with ZSCN nanochains anchoring on RGO nanosheets were successfully synthesized. The morphology, structure, composition and magnetic performance were systematically investigated. Moreover, the microwave absorption (MA) properties of ZSCN nanochains and ZSCN/RGO composites were compared. The results indicate that ZSCN/RGO composites exhibit a minimum reflection loss (RLmin) of −66.38 dB (9.58 GHz) and an effective absorption bandwidth (EAB) of 3.44 GHz (8.12–11.56 GHz) at a thickness of 2.45 mm, due to the synergetic effect between ZnFe 2 O 4 , SiO 2 , carbon, NiO and RGO. • One-dimensional ZnFe 2 O 4 @SiO 2 @C nanochains were synthesized successfully. • The flower-like structure was obtained after NiO nanosheets grew on ZnFe 2 O 4 @SiO 2 @C nanochains by the hydrothermal method. • The microwave absorption mechanism of ZnFe 2 O 4 @SiO 2 @C@NiO/reduced graphene oxide was demonstrated in depth. • The strongest absorption of -66.38 dB and the effective absorption bandwidth of 3.44 GHz can be obtained. [ABSTRACT FROM AUTHOR]