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With the rapid development of current electronic equipment, electromagnetic microwave absorption (EMA) materials with higher design requirements under special circumstances have attracted great attention. Herein, a flexible polyurethane composite foam assisted by coral‐like CNT@Fe3O4/graphene nanocomposites is fabricated by a facile solvothermal and moisture self‐foaming method. The composite foam with 15 wt% nanofillers exhibits an outstanding temperature cycle stability with gradually improved EMA performance at elevated temperature and excellent resilience stability with a tensile strength of 4.81 MPa. An enhanced minimum reflection loss (RLmin) of −59.44 dB at 10.38 GHz with a thickness of 2.28 mm is achieved, while the ultrawide absorption bandwidth of 6.09 GHz nearly covers the full X‐band. This benefits from interface impedance matching, dielectric and magnetic dual losses, and multiple reflections depending on the interior open microcellular structures. It is expected to become a promising thermally tunable microwave absorber in harsh environments. [ABSTRACT FROM AUTHOR]

[Display omitted] • Construct multi-scale architectures from 0D to 2D with abundant heterostructures. • Enhanced microwave absorption of −67 dB with ultrabroad absorption bandwidth. • Rich heterogeneous interfaces and synergistic multiple loss mechanisms for EWA. Two-dimensional (2D) MXene has attracted vast attention in electromagnetic wave absorption (EWA), but there remains a contradiction between maintaining impedance matching and enhancing dielectric loss. Herein, the multi-scale architectures of ecoflex/2D MXene (Ti 3 C 2 T x)@zero-dimensional CoNi sphere@one-dimensional carbon nanotube composite elastomers were successfully constructed by simple liquid-phase reduction and thermo-curing method. The binding between the hybrids as fillers and ecoflex as a matrix greatly enhanced the EWA capability of the obtained composite elastomer and improved its mechanical properties. Owing to its good impedance matching, abundant heterostructures, and synergistic electrical and magnetic losses, this elastomer exhibited an excellent minimum reflection loss of −67 dB at 9.46 GHz under a thickness of 2.98 mm. In addition, its ultrabroad effective absorption bandwidth reached 6.07 GHz. This achievement will pave the way for the exploitation of multi-dimensional heterostructures as high-performance electromagnetic absorbers with superior EWA ability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel wheat-like Ni-coated core–shell silver nanowire using facile one-pot method. • High-efficiency microwave absorption of −61.1 dB with wide absorption bandwidth. • Synergistic effect of unique structure and multiple loss mechanisms for EWA. • Long-term operational stability for three months. Nowadays, developing high-performance electromagnetic functional materials to eliminate the ever-increasing electromagnetic pollution problem is necessary for the complex electromagnetic environment. However, the materials with high electrical conductivity are prone to secondary electromagnetic pollution due to interface impedance mismatching. Herein, the wheat-like electrically conductive and magnetic silver nanowire@nickle (AgNW@Ni) composites were fabricated via a one-pot in-situ growth method. The electromagnetic properties of the composites could be regulated by adjusting different ratios of precursors, resulting in various morphological features of the nanowire as the core with different Ni shell thicknesses. When the Ag and Ni molar ratio was 1:1.1, the AgNW@Ni composite exhibited the optimal minimum reflection loss (RL min) of −61.1 dB with an adequate effective absorption bandwidth (EAB) of 4.06 GHz owing to good impedance matching, abundant heterostructures, and synergistic electrical and magnetic losses. Even after three months, it still maintained an acceptable RL min value of −39.7 dB and similar EAB , demonstrating its long-term operational stability. This unique composite is expected to be applied in more actual electromagnetic protection occasions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flower-like bimetallic MOF-derived carbon composites. • Regulate structures by adjusting different precursor ratios. • High-efficiency microwave absorption of −56.89 dB with wide bandwidth of 4.7 GHz. • Synergistic effect of unique structure and electromagnetic characteristic for EWA. Recently, high-performance functional composites for electromagnetic wave absorption (EWA) with tunable nano/micro-structures have attracted extensive attention. Herein, the flower-like electrically conductive and magnetic cobalt-nickel@carbon (CoNi@C) composites derived from bimetallic metal-organic frameworks (MOFs) were fabricated via solvothermal method and pyrolysis. By adjusting the ratios of different precursors, different morphological features of composites were formed. When the molar ratio of Co and Ni was 1:2, the CoNi@C composites exhibited the optimal minimum reflection loss (RL min) of −56.89 dB at 6.7 GHz with an effective absorption bandwidth of 4.7 GHz, due to the coordinated dielectric and magnetic loss caused by the electromagnetic properties of each component as well as the interactions between the unique three-dimensional (3D) interfaces of flower-like structures that promoted the absorption and dissipation of composites for microwaves. The composites are expected to become promising candidates as high-efficiency absorbers in the electromagnetic protection field. [ABSTRACT FROM AUTHOR]

Developing high-performance microwave absorption (MA) materials becomes an urgent concern in the field of electromagnetic protection. Constructing porous framework is an efficient approach to MA owing to the abilities of adjusting impedance matching and providing more reflection and scattering paths for electromagnetic waves. Herein, a cellulose nanofibril (CNF)/honeycomb-like carbon-shell encapsulated FeCoNi@C/carbon nanotube (CNT) composite aerogel was fabricated via a facile freeze-drying method. The super-lightweight composites showed a distinctive gradient structure for reflection and scattering inside aerogel pores, micrometer small pores, and nano-fillers on the pore walls. The composite aerogel showed an ideal minimum reflection loss (RL min) of −43.6 dB and remarkable adjustable effective absorption bandwidth (EAB) of 12.18 GHz due to good impedance matching, unique gradient porous structure, and synergies of multiple loss mechanisms. Therefore, this work will provide a viable strategy to improve the MA capability of absorbers by taking full advantage of constructing gradient reflection and scattering porous structure. [Display omitted] [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) heterogeneous flower-like spherical MoS 2 /CNTs composites with worm-like interfaces were successfully fabricated by a simplified solvothermal reaction to achieve superb electromagnetic wave absorption (EWA) properties. The microstructure characteristics, morphology features, EWA performance and associated mechanism of as-prepared specimen were systematically analyzed. The incorporation of MoS 2 resulted in the establishment of a 3D conductive network and a substantial augmentation of the heterogeneous interfaces between MoS 2 and carbon nanotubes (CNTs), thereby inducing an amplified conductance loss and polarization loss, respectively. Moreover, the fabrication of 3D architecture not only enhances the structural robustness of the composites, but also broadens the avenue for electromagnetic wave (EW) reflection and scattering, thus augmenting the absorption of EW energy. As a result of the synergistic effect of augmented attenuation capability as well as optimized impedance matching, the EWA performance of materials was outstanding, with a minimum reflection loss (RL min) of −52.1 dB and an effective absorption bandwidth (EAB) of 1.93 GHz achieved at a thin thickness of 2.46 mm in the X band. This research will serve as a meaningful point of reference for exploring 3D flower-like spherical structure of EW absorber. [Display omitted] • 3D heterogeneous flower-like spherical MoS 2 /CNTs composites were prepared. • MoS 2 /CNTs composites have worm-like interfaces. • Superior EMA performance was achieved with minimum reflection loss was −52.1 dB. • The impedance matching and polarization loss was enhanced with MoS 2. • The electromagnetic wave absorption mechanism was proposed. [ABSTRACT FROM AUTHOR]

Currently, electromagnetic interference (EMI) shielding and microwave absorption are two important means to alleviate the increasingly severe electromagnetic (EM) pollution. However, the application areas of EMI shielding and microwave absorption are quite different, so integrating these two capabilities in the same material is a great challenge. Herein, multiple-scale polyurethane (PU) composite foams (CFs) assisted by tadpole-like carbon nanotube (CNT)@Fe 3 O 4 nanocomposites were designed by a facile solvothermal and self-foaming method. By adjusting the CNT@Fe 3 O 4 loadings and ambient temperatures, the EM parameters and interface impedance matching of PU/CNT@Fe 3 O 4 CFs could be optimized, thus realizing the coexistence of EMI shielding and microwave absorption inside one same material. The resulting CF exhibited an effective minimum reflection loss (RL min) of −41.9 dB and EMI shielding effectiveness (SE) of ∼20 dB. Furthermore, the elevated temperatures within a range of −20-60 °C would stimulate the transformation of individual CF from microwave absorption towards EMI shielding capability and vice versa. This work will promote the development of intelligent EM compatible devices in the field of optional EM protection. [Display omitted] • Polyurethane composite foams assisted by multi-dimensional coral-like components • Reversibly switching microwave absorption towards EMI shielding capability • Outstanding and tunable temperature-stimulated EM protection ability [ABSTRACT FROM AUTHOR]