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[Display omitted] With the increased usage of electromagnetic microwaves (EM) in wireless communication technology, the problem of electromagnetic radiation pollution has grown dramatically. This study successfully prepared novel Co/C magnetic nanocomposite fibers for EM absorption using the electrospinning and carbonization methods. The morphology, composition, magnetic properties, and EM absorption performance were extensively characterized. This material shows exceptional EM absorption performance, achieving −72.01 dB (at 2.08 mm) for minimum reflection loss (RL min) and 5.4 GHz (at 1.68 mm) for effective absorption bandwidth (EAB). The performance surpasses not only any single precursor but also stands as the best in similar investigations. It can be attributed to the microstructure of magnetic Co nanoparticles encapsulated in carbon nanofibers and the macrostructure of cross-linked three-dimensional (3D) conductive networks. The combination of these structures resulted in excellent dielectric loss, magnetic loss, and impedance matching. This research offers new insights into the production of one-dimensional (1D) carbon-based absorbers, while also establishing a theoretical foundation for exploring the application potential of this material. These findings may contribute to the development of more efficient and practical EM absorption materials in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] Increasing electromagnetic (EM) radiation has driven the rapid development of carbon-based EM wave absorption materials, but the design of light-weight and efficient carbon-based materials remains a huge challenge. Herein, N -doped carbon fibers embedded with CoNi alloy particles (CoNi/C fibers) were synthesized via electrospinning technology and carbonization. Then, conductive polypyrrole-coated CoNi/C fibers (CoNi/C@PPy composites) were synthesized by chemical polymerization. As-synthesized CoNi/C@PPy composites showed outstanding EM wave absorption property due to the synergistic effect between CoNi, N -doped carbon fibers and PPy. The optimal reflection loss (RL) is -68.78 dB (12.90 GHz) with the thickness of 2.43 mm and the low filler loading of 15 wt%. The widest effective absorption bandwidth (EAB) is 5.62 GHz with the thickness of 2.10 mm and the low filler loading of 20 wt%. The outstanding EM wave absorption property is mainly attributed to 3D network structure, great impedance matching and strong dielectric loss. The results showed that embedding magnetic alloy particles in carbon fibers coated with conductive polymers is an effective strategy for constructing efficient lightweight EM wave absorption materials. [ABSTRACT FROM AUTHOR]

[Display omitted] At present, the magnetic metal/carbon composites have been widely explored for microwave absorption (MA), which effectively integrate the characteristics of magnetic and dielectric materials. As a typical material, metal–organic framework (MOF) shows tremendous potential as a precursor or template. However, its development is limited by the inferior impedance matching. Herein, a novel rod-like Fe/Fe 3 O 4 /FeN/N-doped carbon (FON/NC) composite was synthesized via dual-ligand strategy and following calcination. The outer polypyrrole (PPy) shell, obtained by a facile polymerization method, effectively optimized the impedance matching and observably enhanced the MA capacity. Both the multi-component loss mechanism and unique porous core–shell structures of MOF-derived composites were beneficial for microwave attenuation. The effects of filler loadings (20 wt%, 25 wt%, 30 wt% and 35 wt%) on electromagnetic (EM) properties of FON/NC@PPy composites were discussed. Remarkably, as-obtained composites exhibited a minimum reflection loss (RL) value of −60.08 dB at the layer thickness of merely 1.44 mm and the widest effective absorption bandwidth (EAB, RL ≤ −10 dB) of 5.06 GHz at 1.64 mm with 30 wt% filler loading. This work provides a great reference for designing MOF-derived absorbers with high MA performance. [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] The conductive networks for electron hopping and migration constructed by one-dimensional (1D) composite absorbers are highly desirable to improve the electromagnetic (EM) wave attenuation capacity. Herein, the Ni@Co/C@polypyrrole (PPy) composites integrating the advantages of component and microstructure were fabricated. The addition of Co/C and PPy effectively optimized the impedance matching and improved the EM attenuation. Under the comprehensive impacts of multiple reflections/scattering, conduction loss and interface polarization, the Ni@Co/C@PPy composites showed superior EM wave absorption with the reflection loss (RL) value of −48.76 dB and the effective absorption bandwidth (EAB) of 5.10 GHz at a corresponding thickness of 2.0 mm. The largest EAB could reach 5.54 GHz (7.24–12.78 GHz) at the thickness of 2.2 mm. This work provides a great reference for fabricating 1D novel EM wave absorption materials. [ABSTRACT FROM AUTHOR]

[Display omitted] Nowadays, ferrites/carbon fibers have attracted considerable attention as microwave absorption materials (MA) due to the synergistic effect between dielectric and magnetic loss. Herein, the ZnFe 2 O 4 /C fibers were fabricated via electrospinning and calcination methods, and then polypyrrole (PPy) successfully coated on the fibers via oxidative polymerization. The ZnFe 2 O 4 /C@PPy composites exhibit enhanced EM wave absorption performance with the loading of 25 wt%. The optimal reflection loss (RL) value is up to −66.34 dB (13.80 GHz) and effective absorption bandwidth (EAB) is 5.74 GHz (11.78–17.52 GHz) with a matching thickness of 1.93 mm. Besides, high-efficient absorption performance of the ZnFe 2 O 4 /C@PPy composites is mainly attributed to the dielectric loss and ideal impedance matching. This study reveals a novel approach to development of ferrites/carbon fibers coated with PPy, and the ZnFe 2 O 4 /C@PPy composites exhibit great potential application as the materials with high-efficient absorption properties. [ABSTRACT FROM AUTHOR]

[Display omitted] Metal-organic framework (MOF) materials have caused widespread concerns in the field of microwave absorption, due to the unique microstructure and electronic state. Herein, the CoZn/C@MoS 2 @polypyrrole (PPy) composites were prepared through MOF self-template method. The MoS 2 sheets and PPy shell incorporated for optimizing impedance matching of two-dimensional (2D) CoZn/C composites. The introduction of MoS 2 sheets and PPy shell endowed the composites with enhanced microwave absorption. The as-prepared CoZn/C@MoS 2 @PPy composites showed a minimum reflection loss (RL) of −49.18 dB with the thickness of 1.5 mm. In addition, the effective absorption bandwidth (EAB, RL values exceeding −10 dB) covered 4.56 GHz, which showed greater performances than CoZn/C composites under a lower thickness (<2 mm). This work not only provides a facile route for fabricating MOF-derived carbon-based composites as microwave absorbers, but also broadens the application of MOF 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]

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] In recent years, electromagnetic pollution has become more and more serious, and there is an urgent need for microwave absorbing materials with superior performance. Prussian blue analogue (PBA) is a metal organic framework material with the advantages of diverse morphology and tunable composition. Therefore, PBA has attracted a lot of attention in the field of microwave absorption. In this work, PBA was coated on the surface of carbon composites by hydrothermal method, and then PPy was compounded on its surface after carbonization treatment to construct hierarchical core–shell CoC@CoFe/C@PPy fibers. The fibers have Co-doped C composites as the core and CoFe/C decorated with PPy as the shell. This unique hierarchical structure and various microwave absorption mechanisms are described in detail. The microwave absorption performance is optimized by adjusting the filling of the sample. The best microwave absorption performances are achieved at 25 wt% filling of CoC@CoFe/C@PPy. At a thickness of just 1.69 mm, CoC@CoFe/C@PPy fiebrs have a minimum reflection loss (RL min) of −64.32 dB. When the thickness is 1.88 mm, CoC@CoFe/C@PPy achieves a maximum effective absorption bandwidth (EAB max) of 5.38 GHz. The results indicate that the CoC@CoFe/C@PPy composite fibers have a great potential in the field of microwave absorption. [ABSTRACT FROM AUTHOR]

Abstract: One-dimensional (1D) magnetic Fe3O4/P(GMA–DVB) peapod-like nanochains have been successfully synthesized by magnetic-field-induced precipitation polymerization using Fe3O4 as building blocks and P(GMA–DVB) as linker. The Fe3O4 microspheres without surface modification can be arranged with the direction of the external magnetic field in a line via the dipolar interaction between Fe3O4 microspheres and linked permanently via P(GMA–DVB) coating during precipitation polymerization. The length of peapod-like nanochains can be controlled by magnetic field intensity, and the thickness of polymer shell can be tuned by the amount of monomers. Magnetic measurement revealed that these 1D peapod-like nanochains showed highly magnetic sensitivity. In the presence of magnetic field, 1D magnetic Fe3O4/P(GMA–DVB) peapod-like nanochains can be oriented and aligned along the direction of external magnetic field. [Copyright &y& Elsevier]

NiCo-HFPR-0.2 composite is prepared for high-performance electromagnetic wave absorption, exhibiting the RL min of −61.20 dB at 14.26 GHz and 1.56 mm, the EAB of 4.90 GHz at 1.57 mm, and the reduction in RCS up to 31.0 dB m2 at θ=0°. [Display omitted] • NiCo-HFPR-0.2 composite is successfully fabricated for electromagnetic wave absorption. • The composite has the RL min of −61.20 dB at 14.26 GHz and 1.56 mm and the EAB of 4.90 GHz at 1.57 mm. • These performances are attributed to the multiple losses and impedance match stemming from reasonable structural design. • At θ = 0° and Phi = 0°, the coating of this composite reduces the RCS value by 31.0 dB m2 compared to the sole PEC layer. In contemporary times, electromagnetic radiation poses a significant threat to both human health and the normal functioning of electronic devices. Developing composites as adsorption materials possess exceptional electromagnetic wave absorption performances can efficient address this critical issue. Herein, hollow core–shell NiCo 2 O 4 @polypyrrole nanofibers/reduced graphene oxide (NiCo-HFPR) composites are fabricated by the combination of electrostatic spinning, air calcination, in-situ polymerization, freeze-drying and hydrazine vapor reduction. As anticipated, NiCo-HFPR-0.2 exhibits noteworthy properties, with the minimum reflection loss (RL min) of −61.20 dB at 14.26 GHz and 1.56 mm, as well as the effective absorption bandwidth (EAB) of 4.90 GHz at 1.57 mm. Additionally, the simulation procedure is employed to determine the radar cross-section (RCS) attenuation. In comparison to a singular perfect electrically conductive (PEC) layer, the PEC layer coated with NiCo-HFPR-0.2 consistently yields an RCS value below −10 dB m2 within the range of −60° < θ < 60°. The RCS attenuation value of the NiCo-HFPR-0.2 coating achieves an outstanding 31.0 dB m2 at θ = 0°, strongly affirming the ability to effectively attenuate electromagnetic wave in real-world applications. The employed experimental methodology, the meticulously crafted composite, and the simulation outcomes presented in this study bear great promise for the progressive advancement of both theoretical investigations and practical applications within the domain of electromagnetic wave absorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • The study focuses on the production of CoNi/C nanofibers by electrospinning and carbonization processes, as well as the construction of high-efficiency EMW absorbers. • The optimal optimization strategy was determined through systematic exploration of the effects of altering Co and Ni elemental proportions on the morphology, composition, magnetic and electromagnetic properties of the composite. • The CoNi/C nanofibers with a Co/Ni ratio of 1/3 exhibited exceptional EMW absorption capabilities, with RL min of −71.2 dB (2.4 mm, 13.4 GHz) and EAB of 5.9 GHz (2.2 mm, 12.1–18 GHz). • Simple fabrication of cobalt–nickel alloy/carbon nanocomposite fibers for tunable microwave. A series of CoNi/C nanocomposite fibers with different Co and Ni ratios were successfully prepared by electrospinning and carbonization techniques for the study of electromagnetic microwave (EMW) absorbing materials. We systematically studied the influence of Co and Ni content on the microstructure, chemical composition, magnetic properties, and EMW absorption characteristics of the samples. The results showed that CoNi/C nanocomposite fibers obtained excellent EMW absorption ability through the reasonable design of the composition, and the Co/Ni ratio significantly affected the microstructure and EMW absorption performance. When the Co/Ni ratio was 1/3, the minimum reflection loss (RL min) is −71.2 dB (2.4 mm, 13.4 GHz), and the maximum effective absorption bandwidth (EAB, RL＜-10 dB) is up to 5.9 GHz (2.2 mm, 12.1–18 GHz), covering almost the entire Ku band. This study demonstrated the enormous potential of one-dimensional structure in the field of EMW absorption. In addition, the CoNi/C nanocomposite fiber synthesized using a straightforward and low-cost method not only has excellent EMW absorption performance but also has the potential for practical application. The results of this study provide a simple and effective approach for designing high-performance EMW absorbing materials. [ABSTRACT FROM AUTHOR]

In here, cobalt-zinc bimetallic oxides@polypyrrole (PPy) composites with core–shell structure are prepared, and the prepared Co 3 O 4 /ZnCo 2 O 4 @PPy (CZCP) has a wide absorption of 5.58 GHz, while ZnCo 2 O 4 /ZnO@PPy (ZCZP) has a strong reflection loss of −71.2 dB. [Display omitted] • By changing the ratio of Co2+ and Zn2+ of the MOF precursors, the various cobalt-zinc bimetallic oxides are fabricated. • Cobalt-zinc bimetallic oxides@polypyrrole (PPy) composites with core–shell structure are prepared through in situ polymerization method. • When the loading is 50 wt%, the EAB of Co 3 O 4 /ZnCo 2 O 4 @PPy is 5.58 GHz (12.42–18 GHz) at 1.53 mm, and the RL min of ZnCo 2 O 4 /ZnO@PPy is −71.2 dB at 13.04 GHz and 1.84 mm. Composite materials that combine magnetic and dielectric losses offer a potential solution to enhance impedance match and significantly improve microwave absorption. In this study, Co 3 O 4 /ZnCo 2 O 4 and ZnCo 2 O 4 /ZnO with varying metal oxide compositions are successfully synthesized, which are achieved by modifying the ratios of Co2+ and Zn2+ ions in the CoZn bimetallic metal–organic framework (MOF) precursor, followed by a high-temperature oxidative calcination process. Subsequently, a layer of polypyrrole (PPy) is coated onto the composite surfaces, resulting in the formation of core–shell structures known as Co 3 O 4 /ZnCo 2 O 4 @PPy (CZCP) and ZnCo 2 O 4 /ZnO@PPy (ZCZP) composites. The proposed method allows for rapid adjustments to the metal oxide composition within the inner shell, enabling the creation of composites with varying degrees of magnetic losses. The inclusion of PPy in the outer shell serves to enhance the bonding strength of the entire composite structure while contributing to conductive and dielectric losses. In specific experimental conditions, when the loading is set at 50 wt%, the CZCP composite exhibits an effective absorption bandwidth (EAB) of 5.58 GHz (12.42 GHz-18 GHz) at a thickness of 1.53 mm. Meanwhile, the ZCZP composite demonstrates an impressive minimum reflection loss (RL min) of −71.2 dB at 13.04 GHz, with a thickness of 1.84 mm. This study offers a synthesis strategy for designing absorbent composites that possess light weight and excellent absorptive properties, thereby contributing to the advancement of electromagnetic wave absorbing materials. [ABSTRACT FROM AUTHOR]

Ni NCs@Z-P/RGO composites are prepared for high-performance electromagnetic wave absorption, exhibiting RL min of −63.58 dB at 14.3 GHz with a thickness 1.61 mm, the EAB of 5.08 GHz (11.92 GHz-17 GHz) at a thickness of 1.67 mm, and the reduction in RCS up to 26.6 dB m2 at θ=0°. [Display omitted] • One-dimensional Ni nanochains@Zn2+ doping PPy/reduced graphene oxide composites for electromagnetic wave absorption are fabricated. • The composite has the RL min of −63.58 dB at 14.3 GHz with a thickness 1.61 mm and the EAB of 5.08 GHz (11.92 GHz-17 GHz) at a thickness of 1.67 mm. • At θ = 0° and PHi = 0°, the coating of this material reduces the RCS value by 26.6 dB m2 compared to the uncoated perfectly conducting layer. Nowadays, electromagnetic radiation significantly impacts the normal operation of electronic devices and poses risks to human health. To effectively address this problem, the development of composites that exhibit exceptional electrochemical wave absorption through the combination of different components holds great promise. In this study, we have successfully prepared 1D Ni nanochains@Zn2+ doping polypyrrole/reduced graphene oxide (Ni NCs@Z-P/RGO, denoted as R-x) composites using a combination of hydrothermal, solvothermal, in situ polymerization, and physical blending methods. Notably, the R-2 composite demonstrates a remarkable minimum reflection loss (RL min) of −63.58 dB at 14.3 GHz, with a thickness of 1.61 mm. Furthermore, the R-2 composite exhibits an impressive effective absorption bandwidth (EAB) of 5.08 GHz (11.92 GHz-17 GHz) at a thickness of 1.67 mm. These outstanding performances can be attributed to the synergistic effect of the different components and a well-thought-out structural design. Moreover, to showcase the practical applicability of the material, we have conducted additional investigations on the reduction of the radar cross-sectional area (RCS). The results strongly demonstrate that the prepared composite material, when used as a coating, effectively reduces the RCS value by up to 26.6 dB m2 for R-2 at θ = 0°. The experimental methods and simulations presented in this study hold significant potential for application in wave absorption research and practical implementations. Additionally, the prepared Ni NCs@Z-P/RGO composites demonstrate feasibility as wave-absorbing materials for future utilization. [ABSTRACT FROM AUTHOR]

Fe 3 O 4 @PPy/rGO composites have been fabricated by hydrothermal method, in situ polymerization method, directional freeze-drying and hydrazine vapor reduction, exhibiting the RL min of −61.20 dB at 1.89 mm and the EAB of 5.26 GHz at 1.71 mm. [Display omitted] • Fe 3 O 4 @PPy/rGO (FPG) composites have been fabricated by hydrothermal method, in situ polymerization method, directional freeze-drying and hydrazine vapor reduction. • The enhanced EMW adsorption performances are attributed to the synergy effect of multiple EMW losses stemming from Fe 3 O 4 , PPy, rGO and optimized impedance match. • FPG-4 exhibits the RL min of −61.20 dB at 1.89 mm and the EAB of 5.26 GHz at 1.71 mm. The design of heterostructures with reasonable chemical composition and spatial structure is one of the effective strategies to achieve high performances electromagnetic wave (EMW) absorption. Herein, reduced graphene oxide (rGO) nanosheets decorated with hollow core–shell Fe 3 O 4 @PPy (FP) microspheres have been prepared by the combination of hydrothermal method, in situ polymerization method, directional freeze-drying and hydrazine vapor reduction. FP acting as traps can consume EMW trapped into their interior through the magnetic and dielectric losses. RGO nanosheets forming the conductive network are served as multi-reflected layers. Moreover, the impedance matching is optimized by the synergistic effect between FP and rGO. As expected, the synthetic Fe 3 O 4 @PPy/rGO (FPG) composite shows excellent EMW absorption performances with the minimum reflect loss (RL min) of −61.20 dB at 1.89 mm and the effective absorption bandwidth (EAB) of 5.26 GHz at 1.71 mm. The excellent performances for the heterostructure are attributed to the synergistic effect of conductive loss, dielectric loss, magnetic loss, multiple reflection loss, and optimized impedance matching. This work provides a simple and effective strategy for the fabrication of lightweight, thin and high-performances EMW absorbing materials. [ABSTRACT FROM AUTHOR]

CuS/Fe 3 O 4 @polypyrrole composites are successfully prepared via combining hydrothermal method, solvothermal method and in-situ polymerization method, exhibiting the RL min of −74.12 dB at 2.96 mm and the EAB of 4.6 GHz at 1.68 mm. [Display omitted] • CuS/Fe 3 O 4 @PPy composites are successfully fabricated by combining hydrothermal method, solvothermal method and in-situ polymerization method. • The enhanced electromagnetic loss and the optimized impedance matching are attributed to the synergy effect of CuS, Fe 3 O 4 and PPy. • The RL min of CuS/Fe 3 O 4 @PPy composites is −74.12 dB at 6.82 GHz with the thickness of 2.96 mm. Recently, electromagnetic radiation is a serious threat to equipment accuracy, military safety and human health. The combination with different materials to fabricate absorber composites with well-designed morphology is expected to ameliorate this issue. In here, CuS/Fe 3 O 4 @polypyrrole (CuS/Fe 3 O 4 @PPy) flower-like composites are constructed by the combination of hydrothermal method, solvothermal method and in-situ polymerization. CuS with flower-like structure consisting of nanosheets can provide a conductive backbone and large specific surface area. Hollow Fe 3 O 4 microspheres play a key role in deciding magnetic loss, and electromagnetic waves can penetrate their hollow structure, result in multiple reflection and refraction. PPy coating can enhance the combined strength of composite, and effectively consume microwaves by scattering and multiple refraction in the intercalated structure. As expected, the minimum reflection loss (RL min) of CuS/Fe 3 O 4 @PPy composites is −74.12 dB at 8.16 GHz with a thickness of 2.96 mm, and the effective absorption bandwidth (EAB) is 4.6 GHz (13.4–18.0 GHz) at 1.68 mm. The excellent electromagnetic wave absorption performances are attributed to the synergy effect of different components. This work provides a unique strategy for the structural design of flower-like microspheres in the field of electromagnetic wave absorption. [ABSTRACT FROM AUTHOR]

1D M (Co, Ni)@PANI nanochains are synthesized through reducing the metal element under a parallel magnetic field, pretreating metal nanochains by KH550 and oxidating the aniline monomer. These composites have excellent wave absorption with good impedance matching, exhibiting −73.16 dB at 4.63 mm and −65.96 dB at 1.59 mm for Co@PANI nanochains and Ni@PANI nanochains, respectively. [Display omitted] The development of microwave absorbing materials with strong absorption capacity, wide bandwidth and light weight has always been a topic of concern. Herein, one-dimensional (1D) M (Co, Ni)@polyaniline (PANI) nanochains (NCs) with adjustable thickness have been successfully synthesized by reducing the mental ions under a parallel magnetic field, pretreating metal nanochains with KH550 and pre-oxidization of aniline monomer. It is found that Co has a more favorable absorption width for electromagnetic waves (EMW) and Ni aims at the absorption intensity. Furthermore, the effect of metal elements on adjusting impedance matching is more significant than their magnetic loss for composites. The minimum reflection loss (RLmin) of CoP2 can be up to −73.16 dB at 4.63 mm and the effective absorption bandwidth (EAB) is 4.98 GHz at 2.17 mm, while those of NiP2 are −65.06 dB at 3.88 mm and 5.02 GHz at 2.05 mm. The increase of PANI content can significantly reduce the matching thickness. And the RLmin of CoP3 and NiP3 can reach −58.72 dB at 2.32 mm and −65.96 dB at 1.59 mm, respectively. The absorption mechanism reveals that the matching thickness of the quarter-wavelength determines frequency location. And high absorption intensity is attributed to the synergistic effects of impedance matching, conduction loss, polarization loss, and magnetic loss. This work provides a theoretical basis for designing PANI or other conducting polymers coating magnetic nanochains for electromagnetic absorbing materials with strong absorption capacity, wide bandwidth and light weight. [ABSTRACT FROM AUTHOR]

[Display omitted] Transition metals with catalytic properties were expected to improve the fire resistance of the polymer. In this work, NiMoO 4 nanorods decorated with Co-Ni layered double hydroxide (LDH) were fabricated and incorporated into polyurea (PUA) to improve the flame retardancy during combustion. Thermogravimetric analysis (TGA) showed that the addition of NiMoO 4 @Co-Ni LDH slightly decreased the initial degradation and the maximum degradation temperature. With increasing loading of NiMoO 4 @Co-Ni LDH, the char residue increased obviously. The combustion performance of PUA with 3.0 wt% NiMoO 4 @Co-Ni LDH investigated by cone calorimeter (CCT) showed that the peak heat release rate (PHRR), total heat release (THR) and smoke factor (SF) decreased by 34.41%, 12.68% and 48.65%, respectively. The existence of well-dispersed NiMoO 4 @Co-Ni LDH effectively enhanced the mechanical properties and flame retardant performances of PUA. [ABSTRACT FROM AUTHOR]

[Display omitted] Nowadays, facing the inevitable electromagnetic (EM) pollution caused by many electronic products, it is urgent to develop high-performance microwave absorbing materials. In particular, the bimetallic carbon-based composites derived from MOFs exhibit excellent microwave absorption potential due to their simple preparation, low cost, adjustable morphology and magnetoelectric synergy mechanism. In this work, we successfully prepared plum-like NiCo@C composite by simple solvothermal method and carbonization treatment, which displays strong absorption (-55.4 dB) and wide effective absorption band (EAB, 7.2 GHz) when the loading is 20 wt%. The plum-like structure greatly enriches the non-uniform interface and the structural anisotropy contributes to the dissipation of electromagnetic waves. At the same time, the band hybridization and magnetic coupling of NiCo@C contribute to the coordination of EM characteristics. Overall, this work proves the feasibility of NiCo@C hierarchical composite in the field of microwave absorbing, and provides insight for the development of high-performance absorbers. [ABSTRACT FROM AUTHOR]

[Display omitted] Multiband-compatible stealth materials play an increasingly crucial role in the field of modern military defence because they can enable the targeted objects to dodge advance detection technologies. In this study, chain-like Fe 3 O 4 @poly(ethyleneglycol dimethacrylate- co -methacrylic acid) nanocomposites were constructed as precursors through the magnetic field-induced distillation precipitation polymerisation. Then, the liquid-phase seed-mediated growth method, together with subsequent calcination, was applied to introduce SnO 2 shells and remove poly(ethyleneglycol dimethacrylate- co -methacrylic acid) shells, which led to the successful preparation of innovative core–shell Fe 3 O 4 @SnO 2 nanochains. The unique microstructure and appropriate components endowed nanochains with multiple functional applications. The minimum reflection loss value was approximately −39.4 dB (5.67 GHz), exhibiting excellent microwave absorption performance. The possible microwave absorption mechanisms involve interfacial polarisation, space charge polarisation, natural resonance, and multiple reflections and scatterings. The optimal infrared reflectivity reached 0.64, 0.51, and 0.37 in three atmospheric windows, indicating outstanding infrared stealth performance, which was attributed to the intense infrared reflection of SnO 2 shells. Furthermore, three nanochains showed different colours (dark green, brick red, and bright orange), revealing selection absorption for visible light. This can be attributed to the combined effect of visible responses of SnO 2 shells along with Bragg diffraction from the periodic arrangement of Fe 3 O 4 particles in a single nanochain. Thus, core-shell Fe 3 O 4 @SnO 2 nanochains can be considered as promising radar-infrared-visible compatible stealth materials. This discovery opens a new means to exploit multiband-compatible stealth materials. [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]