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Improving interface connectivity of magnetic nanoparticles in carbon aerogels is crucial, yet challenging for assembling lightweight, elastic, high‐performance, and multifunctional carbon architectures. Here, an in situ growth strategy to achieve high dispersion of metal–organic frameworks (MOFs)‐anchored cellulose nanofibrils to enhance the interface connection quality is proposed. Followed by a facile freeze‐casting and carbonization treatment, sustainable biomimetic porous carbon aerogels with highly dispersed and closely connected MOF‐derived magnetic nano‐capsules are fabricated. Thanks to the tight interface bonding of nano‐capsule microstructure, these aerogels showcase remarkable mechanical robustness and flexibility, tunable electrical conductivity and magnetization intensity, and excellent electromagnetic wave absorption performance. Achieving a reflection loss of −70.8 dB and a broadened effective absorption bandwidth of 6.0 GHz at a filling fraction of merely 2.2 wt.%, leading to a specific reflection loss of −1450 dB mm−1, surpassing all carbon‐based aerogel absorbers so far reported. Meanwhile, the aerogel manifests high magnetic sensing sensibility and excellent thermal insulation. This work provides an extendable in situ growth strategy for synthesizing MOF‐modified cellulose nanofibril structures, thereby promoting the development of high‐value‐added multifunctional magnetic carbon aerogels for applications in electromagnetic compatibility and protection, thermal management, diversified sensing, Internet of Things devices, and aerospace. [ABSTRACT FROM AUTHOR]

[Display omitted] One-dimensional carbon-based materials have emerged as promising electromagnetic wave absorption agents due to their outstanding conductivity, high stability, low weight, and easy availability. Properly optimizing their electromagnetic parameters is expected to further enhance the electromagnetic wave attenuation capacity. In this work, efficient Cu 9 S 5 /C nanocomposite fibers are prepared by a combined approach of electrospinning and subsequent carbonization-sulfurization processes. The Cu 9 S 5 nanoparticles with size of ca. 100–200 nm were homogeneously embedded in fibrous carbon matrix with diameter of 300 nm. For electromagnetic wave absorption, the optimized composited nanofibers (Cu 9 S 5 /C-3) exhibited an extremely superb reflection loss of −65.4 dB (9.5 GHz, 2.7 mm) at a lower mass fraction (20 wt%). And the effective absorption bandwidth could be up to 4.1 GHz (8.0–12.1 GHz) with a matching thickness of 2.9 mm, covering the whole X-band. Electromagnetic wave attenuation mechanism investigation revealed that the performance enhancement originated from the synergy of various loss pathways, including interfacial polarization, dipole polarization, and conductive loss. The unique hierarchical structure from particle embedding, one-dimensional fiber, to three-dimensional network further amplified the performance advantages of each component. This work is anticipated to provide a feasible strategy to synthesize sulfide/carbon binary composite fibers for efficient electromagnetic wave absorption. [ABSTRACT FROM AUTHOR]

Broadening absorption bandwidth is of great significance to extend application scenarios for electromagnetic wave (EMW) absorption materials. Since the electromagnetic character changes caused by high shape anisotropy, one-dimensional fibrous materials have been widely concerned. In this work, manganese sulfide (MnS)/carbon nanocomposite fibers are facilely synthesized by a facile combination of electrospinning and high-temperature processing. The fibrous carbon supports with a 350-nm average diameter are embedded with dense MnS nanoparticles on the surface. Under the premise of ensuring a strong EMW absorption intensity (−68.9 dB, 11.1 GHz, 3.6 mm), the MnS/carbon nanocomposite fibers can achieve a wide effective absorption bandwidth of 7.2 GHz (9.5–16.7 GHz, 3.3 mm). In-depth study verifies that MnS can help to achieve superior synergy between conductive and polarized attenuation capacity, enhance the attenuation ability and optimize impedance matching characteristic. Besides, considering the few studies about MnS in this field, this work confirmed the huge potentials of MnS for EMW absorption applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Low density, high stability and strong dielectric loss capacity endow carbon-based nanocomposites with superb microwave dissipation performances. Different from grapheme or carbon nanotubes, the graphitization degrees of carbon-based composites derived from the organic precursor pyrolysis can be accurately regulated by controlling the carbonization temperature. As such, their electromagnetic properties can be easily tuned. In this work, we report the preparation of TiO 2 /Co/Carbon nanofibers (CNFs) through a combined approach of electrospun and carbonization at different temperatures. The nanofibers with an average diameter of 300 nm were coated by a dense layer of TiO 2 and embedded by Co/CoO nanoparticles. The performance evaluation indicated the composite obtained at 700 °C exhibits remarkably strong absorption of −63.2 dB at 9.8 GHz and wide effective absorption bandwidth of 6.4 GHz with a pretty low filling rate of 15 wt%. Further analysis on the electromagnetic behaviors shows that the composite possesses regulable impedance matching characteristic and absorption performances, implying the huge application potential under various demand conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoO 2 modified Ni/CNFs is synthesized by facile electrospinning and carbonization. • Synergistic magnetic-dielectric attenuation conduces to effective EMW absorption. • Polarization behavior is revealed by simulating the electric field distribution. • Far-field EMW absorption competence is forecasted by radar cross section. One-dimensional carbon-based nanofibers are considered as a group of the most promising candidates applied in electromagnetic wave absorption owing to their shape anisotropy, tractability, and stability. To further meet the requirements of lightweight, broadband and effective features, in this work, nickel/carbon nanofibers modified with molybdenum dioxide were resoundingly fabricated through electrospinning and subsequent carbonization. According to textural characteristic analyses, nickel nanoparticles with a diameter of approximately 30 nm were supported on the surface of the carbon nanofibers, while the smaller MoO 2 grains were embedded inside. Under the premise of realizing an outstanding electromagnetic wave absorption intensity (−64.0 dB at 8.0 GHz), the ternary composites achieved a wide effective absorption bandwidth up to 6.9 GHz (9.5 GHz–16.4 GHz). Based on the investigations of electromagnetic parameters and field distribution simulation results, the interwoven network structure and the synergistic effect between each component not only endowed the materials with perfect impedance matching, but introduced manifold loss mechanisms including magnetic loss, conductivity loss and multiple polarization relaxation. Thus, this work provided theoretical guidance and enlightenment for the design of new generation fibrous electromagnetic wave absorbers. [ABSTRACT FROM AUTHOR]

Fabrication of multi-component composites is regarded as an effective strategy to obtain efficient electromagnetic (EM) wave absorption materials. Nevertheless, it is still challenging to find effective approaches to reasonably collocate compositions and construct microstructures to achieve the synergetic effects. In this work, Ni embedded TiO 2 /C core-shell ternary nanofibers were fabricated by a combined method of electrospinning and subsequent thermal treatment. The surface of the carbon nanofibers of 200 nm in diameter was coated with a rough and wrinkled layer of TiO 2 , and metallic Ni nanoparticles with size of 20–30 nm were uniformly embedded in the matrix of the nanofibers. The ternary nanofibers with the molar ratio of 4:1 between TiO 2 and metallic Ni exhibited excellent maximum effective absorption bandwidth of 6.7 GHz at 2.6 mm, with minimum reflection loss value reaching −74.5 dB at 2.0 mm. It is found that TiO 2 optimized impedance matching characteristics and metallic Ni promoted attenuation capacity through electromagnetic parameter regulation. This work not only showed the huge application promise for the ternary composites, but also provided meaningful theoretical guidance for the design of high-efficiency EM wave absorption materials in future studies. Image 1 [ABSTRACT FROM AUTHOR]

• A facile method to design carbon nanofibers loaded with oxides or metals. • Unique 3D micro-network morphology contributing to electromagnetic absorption. • Deeply investing the separate function of dielectric metal oxide and magnetic metal. • Employing 2D projection images of impedance matching characteristic to assist in the analysis. • Revealing the inner attenuation mechanism of enhanced electromagnetic absorption performances. Carbon materials are widely used for electromagnetic wave absorption. However, to find out a more rational approach to improve the electromagnetic (EM) wave absorption performance is still worthy of attention. In this work, the carbon nanofibers (CNFs) decorated by titanium oxide and metallic cobalt (TiO 2 /Co/CNFs) were synthesized by electrospinning and carbonizing process, and the microtopography, structure, composition and magnetic properties of which were characterized in detail. The TiO 2 /Co/CNFs nanocomposites acquired optimal electromagnetism parameters and exhibited superb electromagnetic wave absorption property. The results showed that the minimum reflection loss (RL) values of TiO 2 /Co/CNFs samples with different filling ratios are less than −50 dB with the matching thickness less than 3.5 mm. The maximum effective absorption bandwidths (RL ≤ −10 dB) exceed 5.2 GHz. Besides, the strong absorption frequency range can be regulated by adjusting filling ratios to broaden the application. This work provides a unique approach to design carbon nanofibers loaded with oxides or metals, and the TiO 2 /Co/CNFs nanocomposites could be an ideal candidate as light-weight and high-efficiency electromagnetic wave absorption materials and the tunable absorption property portend the potential application in various environmental conditions. [ABSTRACT FROM AUTHOR]

The sustainable cellulose nanofibril (CNF) was efficiently utilized to facilitate the preparation of a type of ultralight, high-porosity carbon nanotube (CNT) hybrid aerogel-based electromagnetic wave (EMW) absorbers. CNF not only serves as a green surfactant to avoid the agglomeration of CNT, but also acts as supporting matrix or binder to promote the construction of porous CNT-based aerogels. Furthermore, the CNF precursor contributes to the generation of CNF-derived nanocarbon (CNFC) for a high-efficiency dielectric modulator, leading to the tuneable electromagnetic parameters and good impedance matching. Combined with the loss capacity of CNFC, the EMW absorption performance of CNT-based aerogels is enhanced. Consequently, the hybrid aerogels show EMW absorption performance involving an effective absorption bandwidth of 3.3 GHz and an ultrahigh reflection loss of −76.46 dB at a filling ratio of 5 wt%, outperforming that of other CNT-based EMW absorbers ever reported. The synergistic effects of multiple EMW absorption mechanisms for the hybrid aerogels were analyzed at length, demonstrating the indispensable roles of the CNF or CNFC in constructing high-efficiency CNT-based EMW absorbers. Combined with the green, sustainable, facile, and scalable preparation approach, the carbon aerogel-based EMW absorbers are highly promising for applications in electromagnetic compatibility or protection and aerospace. [Display omitted] • Multifunctional, indispensable roles of the cellulose-derived carbon are demonstrated on constructing efficient EMW absorbers. • Preparing ultralow-density aerogels with an easy, scalable production process. • Hybrid aerogel exhibits an optimum reflection loss of −76.46 dB at a low filling ratio of 5 wt%. [ABSTRACT FROM AUTHOR]

A type of nickel/manganese oxide (Ni/MnO)/carbon nanocomposite fibers were prepared via a facile and scalable electrospinning and carbonization approach. In comparison to the pure carbon showing a severe agglomeration, the uniformly embedded MnO and Ni nanoparticles promoted the formation of the fibrous carbon-based nanocomposites with an average diameter of 250 nm and a rough surface. The synergistic coactions of the MnO nanoparticles acting as impedance modulating mediator, the magnetic Ni nanoparticles, and the conductive, fibrous carbon with large aspect ratio and rough surface contributed to the excellent electromagnetic wave (EMW) absorbing performance of the nanocomposites. The nanocomposites with a MnO/Ni ratio of 1:1 exhibited an effective absorption bandwidth of 6.5 GHz at a thickness of 2.9 mm and a minimum reflection loss of −53.23 dB at a thickness of 2.3 mm. The EMW absorption mechanisms of the nanocomposite fibers were discussed at length, which showed the importance of the multi-component building units and microstructure for achieving high EMW absorbing performance. This work thus suggested a convenient, facile, and scalable manufacturing approach for constructing high-performance multi-component nanocomposite fiber based EMW absorbing materials. [ABSTRACT FROM AUTHOR]