Microwave absorption enhancement of multifunctional composite microspheres with spinel Fe3 O4 Cores and Anatase TiO2 shells

Magnetic targeting and pH-microwave dual responsive Janus mesoporous silica nanoparticles for drug encapsulation and delivery

In this paper, a new Janus-structured nano drug delivery carrier Fe3O4@TiO2&mSiO2was designed and synthesized, which consisted of a spherical head and a closely connected rod. The head was a nanocomposite of core/shell structure with magnetic spinel ferric tetraoxide core and anatase titanium dioxide shell (Fe3O4@TiO2), and the rod was ordered mesoporous silica (mSiO2). The nanocarriers showed excellent magnetic targeting capability (saturation magnetization, 25.18 emu g-1). The core/shell heads endowed the carriers with fine microwave responsiveness. The pore volume of mesoporous nanocarriers was 0.101 cm3g-1, and the specific surface area was 489.0 m2g-1. Anticancer drug doxorubicin could be loaded in the mesoporous of the carriers to form Fe3O4@TiO2&mSiO2-DOX. The drug loading capacity was 10.4%. Fe3O4@TiO2&mSiO2-DOX exhibited acid-sensitive and microwave-sensitive release properties along with good bio-compatibility. Fe3O4@TiO2&mSiO2Janus nanoparticles are expected to be ideal drug carriers.

Interface-induced dual-pinning mechanism enhances low-frequency electromagnetic wave loss

Improving the absorption of electromagnetic waves at low-frequency bands (2-8 GHz) is crucial for the increasing electromagnetic (EM) pollution brought about by the innovation of the fifth generation (5G) communication technology. However, the poor impedance matching and intrinsic attenuation of material in low-frequency bands hinders the development of low-frequency electromagnetic wave absorbing (EMWA) materials. Here we propose an interface-induced dual-pinning mechanism and establish a magnetoelectric bias interface by constructing bilayer core-shell structures of NiFe2O4 (NFO)@BiFeO3 (BFO)@polypyrrole (PPy). Such heterogeneous interface could induce distinct magnetic pinning of the magnetic moment in the ferromagnetic NFO and dielectric pinning of the dipole rotation in PPy. The establishment of the dual-pinning effect resulted in optimized impedance and enhanced attenuation at low-frequency bands, leading to better EMWA performance. The minimum reflection loss (RLmin) at thickness of 4.43 mm reaches -65.30 dB (the optimal absorption efficiency of 99.99997%), and the effective absorption bandwidth (EAB) can almost cover C-band (4.72 ~ 7.04 GHz) with low filling of 15.0 wt.%. This work proposes a mechanism to optimize low-frequency impedance matching with electromagnetic wave (EMW) loss and pave an avenue for the research of high-performance low-frequency absorbers.

Preparation of surface molecular imprinting fluorescent sensor based on magnetic porous silica for sensitive and selective determination of catechol

A magnetic fluorescent molecularly imprinted sensor was successfully prepared and implemented to determine catechol (CT). Fe3O4 nanoparticles were synthesized by the solvothermal technique and mesoporous Fe3O4@SiO2@mSiO2 imprinted carriers were prepared by coating nonporous and mesoporous SiO2 shells on the surface of the Fe3O4 subsequently. The magnetic surface molecularly imprinted fluorescent sensor was created after the magnetic mesoporous carriers were modified with γ-methacryloxyl propyl trimethoxy silane to introduce double bonds on the surface of the carries and the polymerization was carried out in the presence of CT and fluorescent monomers. The magnetic mesoporous carriers were modified with γ-methacryloxyl propyl trimethoxy silane and double bonds were introduced on the surface of the carriers. After CT binding with the molecularly imprinted polymers (MIPs), the fluorescent intensity of the molecularly imprinted polymers (Ex = 400 nm, Em = 523 nm) increased significantly. The fluorescent intensity ratio (F/F0) of the sensor demonstrated a favorable linear correlation with the concentration of CT between 5 and 50 μM with a detection limit of 0.025 μM. Furthermore, the sensor was successfully applied to determine CT in actual samples with recoveries of 96.4-105% and relative standard deviations were lower than 3.5%. The results indicated that the research of our present work provided an efficient approach for swiftly and accurately determining organic pollutant in water.

Hierarchical Co2 P/CoS2 @C@MoS2 Composites with Hollow Cavity and Multiple Phases Toward Wideband Electromagnetic Wave Absorption

The synergistic effect of hollow cavities and multiple hetero-interfaces displays huge advantages in achieving lightweight and high-efficient electromagnetic wave absorption, but still confronts huge challenges. Herein, hierarchical Co2 P/CoS2 @C@MoS2 composites via the self-sacrificed strategy and a subsequent hydrothermal method have been successfully synthesized. Specifically, ZIF-67 cores first act as the structural template to form core-shell ZIF-67@poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (ZIF-67@PZS) composites, which are converted into hollow Co2 P@C shells with micro-mesoporous characteristics because of the gradient structural stabilities and preferred coordination ability. The deposition of hierarchical MoS2 results in phase transition (Co2 P→Co2 P/CoS2 ), yielding the formation of hierarchical Co2 P/CoS2 @C@MoS2 composites with hollow cavities and multiple hetero-interfaces. Benefiting from the cooperative advantages of hollow structure, extra N,P,S-doped sources, lattice defects/vacancies, diverse incoherent interfaces, and hierarchical configurations, the composites deliver superior electromagnetic wave capability (-56.6 dB) and wideband absorption bandwidth (8.96 GHz) with 20 wt.% filler loading. This study provides a reliable and facile strategy for the precise construction of superior electromagnetic wave absorbents with efficient absorption attenuation.

Controllable Synthesis of Highly Symmetrical Streamlined Structure for Wideband Microwave Absorption

Highly symmetrical and streamlined nanostructures possessing unique electron scattering, electron-phonon coupling, and electron confinement characteristics have attracted a lot of attention. However, the controllable synthesis of such a nanostructure with regulated shapes and sizes remains a huge challenge. In this work, a peanut-like MnO@C structure, assembled by two core-shell nanosphere is developed via a facile hydrogen ion concentration regulation strategy. Off-axis electron holography technique, charge reconstruction, and COMSOL Multiphysics simulation jointly reveal the unique electronic distribution and confirm its higher dielectric sensitive ability, which can be used as microwave absorption to deal with currently electromagnetic pollution. The results reveal that the peanut-like core-shell MnO@C exhibits great wideband properties with effective absorption bandwidth of 6.6 GHz, covering 10.8-17.2 GHz band. Inspired by this structure-induced sensitively dielectric behavior, promoting the development of symmetrical and streamlined nanostructure would be attractive for many other promising applications in the future, such as piezoelectric material and supercapacitor and electromagnetic shielding.

Bimetallic nanocubes embedded in biomass-derived porous carbon to construct magnetic/carbon dual-mechanism layered structures for efficient microwave absorption

Biomass-derived porous carbon materials have great potential for the development of lightweight and efficient broadband microwave absorbers. In this study, we reported the successful immobilization of Co3O4/CoFe2O4 nanocubes on porous carbon derived from ginkgo biloba shells by activated carbonization and electrostatic self-assembly processes. The optimal reflection loss value of the prepared BPC@Co3O4/CoFe2O4 reaches -68.5 dB when the filling load is 10 wt%, and the effective absorption bandwidth is 6.2 GHz with a matching thickness of 2 mm. The excellent microwave absorption (MA) performance is attributed to the rational three-dimensional structural design, the modulation of magnetic/carbon components, the optimized impedance matching, and the coordinated action of multiple mechanisms. It was further demonstrated by high-frequency structural simulation that the composite can effectively dissipate microwave energy in practical applications. Therefore, the results indicate a favorable potential of the synthesis and application of semiconductor/magnetic component/biomass-derived carbon microwave absorbing materials.

Preparation and characterization of bifunctional wolfsbane-like magnetic Fe3O4 nanoparticles-decorated lignin-based carbon nanofibers composites for electromagnetic wave absorption and electrochemical energy storage

Recently, with the pursuit of high-efficiency electromagnetic wave absorption (EMWA) and electrochemical energy storage (EES) materials, multifunctional lignin-based composites have attracted significant interest due to their low cost, vast availability, and sustainability. In this work, lignin-based carbon nanofibers (LCNFs) was first prepared by electrospinning, pre-oxidation and carbonization processes. Then, different content of magnetic Fe3O4 nanoparticles were deposited on the surface of LCNFs via the facile hydrothermal way to produce a series of bifunctional wolfsbane-like LCNFs/Fe3O4 composites. Among them, the synthesized optimal sample (using 12 mmol of FeCl3·6H2O named as LCNFs/Fe3O4-2) displayed excellent EMWA ability. When the minimum reflection loss (RL) value achieved -44.98 dB at 6.01 GHz with an thickness of 1.5 mm, and the effective absorption bandwidth (EAB) was up to 4.19 GHz ranging from 5.10 to 7.21 GHz. For supercapacitor electrode, the highest specific capacitance of LCNFs/Fe3O4-2 reached 538.7 F/g at the current density of 1 A/g, and the capacitance retention remained at 80.3 %. Moreover, an electric double layer capacitor of LCNFs/Fe3O4-2//LCNFs/Fe3O4-2 also showed a remarkable power density of 7755.29 W/kg, outstanding energy density of 36.62 Wh/kg and high cycle stability (96.89 % after 5000 cycles). In short, the construction of this multifunctional lignin-based composites has potential applications in electromagnetic wave (EMW) absorbers and supercapacitor electrodes.

State of the art and prospects of Fe3O4/carbon microwave absorbing composites from the dimension and structure perspective

At present, to solve the threat of electromagnetic wave (EMW) radiation pollution to human health, intelligent control and information security, tremendous efforts have been made to manufacture EMW absorbing materials. For ideal microwave absorption materials (MAMs), it is generally necessary not only to pursue strong microwave absorption (MA) over wide effective absorption bandwidth (EAB), but also to take into account the requirements of light weight, thin matching thickness and chemical stability characteristics. It has been found that magnetite (Fe3O4) is the most promising MAM to absorb and dissipate EMW among various absorbers, because of its good mechanical and chemical stability, controllable morphology, high Curie temperature, easy preparation, economy and excellent magnetic properties. However, the application performance of Fe3O4 absorber with single composition is limited by its easy agglomeration, eddy current, high density, and impedance mismatch. In addition, achieving efficient MA metrics with low absorber loading remains a huge challenge. To overcome these limitations, conjugation with dielectric carbon-based materials and special structural designs have been extensively explored as viable solutions to optimize the microwave absorption performance (MAP) of Fe3O4. This paper reviews the recent research progress of Fe3O4/carbon MAMs, and then the influence of dimensions and structures regulations on the MAPs are introduced in detail. Finally, the current existing problems and future development direction of Fe3O4/carbon composites in the field of MA are also presented.

Designing flower-like MOFs-derived N-doped carbon nanotubes encapsulated magnetic NiCo composites with multi-heterointerfaces for efficient electromagnetic wave absorption

In order to acquire exceptional electromagnetic wave absorption properties, the microstructure design and component modification of composites are essential. Metal-organic frameworks (MOFs), due to the unique metal-organic crystalline coordination, tunable morphology, high surface area, and well-defined pores, have been regarded as promising electromagnetic wave absorption materials precursors. However, the inadequate contact abilities between adjacent MOFs nanoparticles endow it with undesirable electromagnetic wave dissipation capacity at a low filler loading, which is a great challenge to break size effect of nanoparticles to achieve efficient absorption. Herein, NiCo-MOFs derived N-doped carbon nanotubes encapsulated with NiCo nanoparticles anchored on flowers-like composites (denoted as NCNT/NiCo/C) were successfully prepared through facile hydrothermal method followed by thermal chemical vapor deposition with melamine-assisted catalyst. By controlling the Ni/Co ratio in precursor, the tunable morphology and microstructure of MOFs are achieved. Most importantly, the derived N-doped carbon nanotubes tightly connect the adjacent nanosheets to construct the special 3D interconnected conductive network, which effectively accelerates the charge transfer and improves the conduction loss. And notably, the NCNT/NiCo/C composite delivers excellent electromagnetic wave absorption performance with minimum reflection loss of -66.1 dB and wide effective absorption bandwidth up to 4.64 GHz when the Ni/Co ratio is 1:1. This work provides a novel method for the preparation of morphology controllable MOFs-derived composites and realizes high-performance electromagnetic wave absorption properties.

Magnetic Composite Rapidly Treats Staphylococcus aureus-Infected Osteomyelitis through Microwave Strengthened Thermal Effects and Reactive Oxygen Species

It is difficult to effectively treat bacterial osteomyelitis using photothermal therapy or photodynamic therapy due to poor penetration of light. Here, a microwave (MW)-excited magnetic composite of molybdenum disulfide (MoS₂ ) / iron oxide (Fe₃ O₄ ) is reported for the treatment of bacteria-infected osteomyelitis. In in vitro and in vivo experiments, MoS₂ /Fe₃ O₄ is shown to effectively eradicate bacteria-infected mouse tibia osteomyelitis, due to MW thermal enhancement and reactive oxygen species (ROS) (¹ O₂ and ·O₂ ^- ) production under MW radiation. In addition, the mechanism of MW heat generation is proposed by MW network vector analysis. By the density functional theory and finite element method, the ROS generation mechanism is proposed. The synergy or conductive network between dielectric MoS₂ and magnetic Fe₃ O₄ can reach both enhancement of the dielectric and magnetic attenuation capability. In addition, abundant interfaces are generated to enhance the attenuation of electromagnetic waves by MoS₂ and Fe₃ O_4, introducing multiple reflections and interfacial polarization. Therefore, MoS₂ /Fe₃ O₄ has excellent MW absorption ability based on the synergy or conductive network between MoS₂ and magnetic Fe₃ O₄ as well as multiple dielectric reflections and interfacial polarization.

Autogenous and Tunable CNTs for Enhanced Polarization and Conduction Loss Enabling Sea Urchin-Like Co3ZnC/Co/C Composites with Excellent Microwave Absorption Performance

ZIF-67-derived magnetic metal/carbon composites are considered prospective candidates for use as microwave absorption (MA) materials owing to their magnetoelectric synergy. However, the structure of ZIF-67-derived MA materials mainly depends on the morphology and composition of pristine metal-organic frameworks (MOFs), and their microstructures lack a rational design. Herein, a multidimensional sea urchin-like carbon nanotubes (CNTs)-grafted carbon polyhedra-encapsulated Co₃ZnC/Co nanoparticle composite was prepared by one-step catalytic pyrolysis of ZIF-67/ZnO using a rational structural design. The autogenous and tunable CNTs obtained with the assistance of zinc evaporation not only overcome the limitation of homogeneous dispersion but also endow the Co₃ZnC/Co/C composite with outstanding MA properties owing to the conduction loss provided by CNTs, polarization loss caused by multiple components, and electromagnetic wave trap composed of a special sea urchin-like structure. Consequently, the minimum reflection loss of ZZ_0.1-600 reaches -60.3 dB at 1.6 mm, the maximum absorption bandwidth of ZZ_0.05-600 is 6.24 GHz (covering nearly the entire Ku band) at 1.9 mm, and the structure has a low weight ratio (30 wt %). Compared with Z-600 and pure ZnO, the MA performance of the sea urchin-like Co₃ZnC/Co/C composite obtained by rational structural design has been greatly improved; this strategy offers a new approach for optimizing the MA performance of materials according to their structural design.

Magnetic Interacted Interaction Effect in MXene Skeleton: Enhanced Thermal-Generation for Electromagnetic Interference Shielding

With the rapid advancements of portable and wearable equipment, high-efficiency electromagnetic interference (EMI) shielding materials are highly entailed to eliminate radiated electromagnetic pollution. Herein, by assembling hexagonal SrFe₁₂ O₁₉ flakes into a Ti₃ C₂ T_x MXene/MWCNT substrate, a magnetized Ti₃ C₂ T_x -based film is successfully fabricated by a facile filtration approach. Carbon nanotubes are used as isolation agents to realize the submicroscopic dispersion of MXene and SrFe₁₂ O₁₉ . The obtained MXene/MWCNTs/SrFe₁₂ O₁₉ film shows a high electrical conductivity of 438 S cm^-1 and an excellent EMI shielding effectiveness of 62.9 dB in X-band at a thickness of only 40 µm. Benefiting from a strong magnetic response ability and an expanded magnetic coupling space, hexagonal SrFe₁₂ O₁₉ sheets can efficiently consume incident magnetic field energy by domain wall migration and the ferromagnetic resonance effect. Boosted EMI shielding performance can be achieved by improving the magnetic loss in the Ti₃ C₂ T_x MXene/MWCNTs/SrFe₁₂ O₁₉ film, preventing the secondary reflection of electromagnetic waves. Meanwhile, magnetized MXene-based films display the freestanding and flexible features and are suitable for installation in electric devices. It is anticipated that this strategy offers new ideas for designing EMI shielding films and in broadening potential utility of MXene-based materials.

Novel MOF-derived 3D hierarchical needlelike array architecture with excellent EMI shielding, thermal insulation and supercapacitor performance

The upcoming 5G era will powerfully promote the development of intelligent society in the future, but it will also bring serious electromagnetic pollution. Thus, the development of efficient, lightweight and multifunctional electromagnetic shielding materials and devices is an important research hotspot around the world. Herein, a novel needlelike Co₃O₄/C array architecture is constructed from MOF precursor via a simple pyrolysis process, and its microstructure is controllably tailored by changing the pyrolysis temperature. The unique 3D hierarchical structure and multiphase components enable the architecture to provide high-efficiency electromagnetic interference (EMI) shielding, along with good thermal insulation. More importantly, the architecture possesses fast ion transport channels, which can be used to construct supercapacitors with high specific capacitance and excellent cycle stability. Obviously, this work offers a new inspiration for the design and construction of multifunctional electromagnetic materials and devices.

In situ SERS monitoring of intracellular H2O2 in single living cells based on label-free bifunctional Fe3O4@Ag nanoparticles

Visualization of signaling molecules in single living cells is crucial for understanding cellular metabolism and physiology, which can provide valuable insights into early diagnoses and treatments of diseases. Highly sensitive in situ monitoring of intracellular analytes released from single living cells by virtue of label-free nanosensors is urgently needed, which can avoid interferences from molecular labeling. Here, we proposed an ultrasensitive strategy for in situ imaging of intracellular H₂O₂ in single living cancer cells by surface-enhanced Raman scattering (SERS) spectroscopy with the utilization of label-free Fe₃O₄@Ag core-satellite nanoparticles (NPs). The Fe₃O₄@Ag NPs can efficiently and selectively catalyze the oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H₂O₂. Additionally, they exhibit excellent SERS activity that allows for in situ monitoring of intracellular H₂O₂ in living cells through establishing the correlation between the H₂O₂ level and the SERS intensity of the catalytic oxidation product of TMB. The H₂O₂ concentration is revealed through the SERS intensity of oxidized TMB with a good linear response in a wide range from 1 fM to 1 mM. Moreover, the intracellular H₂O₂ level in live cancer cells and imaging of the distribution of H₂O₂ inside single cells can be achieved by using such a label-free nanosensor based strategy. Our work demonstrates that the label-free Fe₃O₄@Ag NP-based SERS imaging and quantification strategy is a promising and powerful approach to assess intracellular H₂O₂ in living cells and allows us to monitor single-cell signaling molecules with nanoscale resolution.

Development of SERS-based immunoassay for the detection of cryptococcosis biomarker

The surface-enhanced Raman scattering (SERS) technique has displayed a broad application prospect in disease diagnosis owing to its high sensitivity, fast responsiveness, and high specificity. In this study, we developed a SERS-based immunoassay for the detection of cryptococcal capsular polysaccharide (glucuronoxylomannan, GXM), which is an important biomarker of cryptococcosis. The coupled localized surface plasmon resonance effect between magnetic SERS substrates and SERS tags gave rise to an enhanced Raman signal upon the formation of sandwich complexes, which contributes to the sensitive and specific detection of GXM. As a result, the developed method provided a lower limit of detection (1.25 ng/mL) than conventional methods, such as latex agglutination, lateral flow assay, and enzyme-linked immunosorbent assay. Additionally, a recovery experiment was performed to detect GXM in human serum, which also validated the potential advantages of a SERS-based immunoassay in the clinical diagnosis of cryptococcosis.

Size-Dependent Oxidation-Induced Phase Engineering for MOFs Derivatives Via Spatial Confinement Strategy Toward Enhanced Microwave Absorption

Precisely reducing the size of metal-organic frameworks (MOFs) derivatives is an effective strategy to manipulate their phase engineering owing to size-dependent oxidation; however, the underlying relationship between the size of derivatives and phase engineering has not been clarified so far. Herein, a spatial confined growth strategy is proposed to encapsulate small-size MOFs derivatives into hollow carbon nanocages. It realizes that the hollow cavity shows a significant spatial confinement effect on the size of confined MOFs crystals and subsequently affects the dielectric polarization due to the phase hybridization with tunable coherent interfaces and heterojunctions owing to size-dependent oxidation motion, yielding to satisfied microwave attenuation with an optimal reflection loss of -50.6 dB and effective bandwidth of 6.6 GHz. Meanwhile, the effect of phase hybridization on dielectric polarization is deeply visualized, and the simulated calculation and electron holograms demonstrate that dielectric polarization is shown to be dominant dissipation mechanism in determining microwave absorption. This spatial confined growth strategy provides a versatile methodology for manipulating the size of MOFs derivatives and the understanding of size-dependent oxidation-induced phase hybridization offers a precise inspiration in optimizing dielectric polarization and microwave attenuation in theory.

Improving oxygen reduction reaction of microbial fuel cell by titanium dioxide attaching to dual metal organic frameworks as cathode

In this study, a two-step simple distributed feeding method was used to prepare the core-shell nanocomposite dual metal organic frameworks (D-MOFs, TiO₂@ZIF-67/ZIF-8). There were three obvious peaks (011), (112), (222) interface in D-MOFs core, which fully showed that ZIF-67/ZIF-8 crystal core was successfully synthesized. The morphology of composite material was core-shell structure with a rough surface, and Ti, Co, Zn, Al were uniformly distributed on the surface. TiO₂@ZIF-67/ZIF-8 also had excellent electrochemical activity and the maximum power density of TiO₂@ZIF-67/ZIF-8 microbial fuel cell (MFC) was 341.506 mW/m², which was 1.30 times of ZIF-67/ZIF-8-MFC (262.144 mW/m²) and 2.07 times of ZIF-67-MFC (164.836 mW/m²). And the continuous output voltage of TiO₂@ZIF-67/ZIF-8-MFC was 413.43 mV, which could maintain stable voltage output for 8.3 days. D-MOFs as the core of composites ensured the integrity, stability and high activity of materials; Rough TiO₂ as the surface of the material provided surface area and reaction center.

Dimensional Design and Core-Shell Engineering of Nanomaterials for Electromagnetic Wave Absorption

Electromagnetic (EM) wave absorption materials possess exceptionally high EM energy loss efficiency. With vigorous developments in nanotechnology, such materials have exhibited numerous advanced EM functions, including radiation prevention and antiradar stealth. To achieve improved EM performance and multifunctionality, the elaborate control of microstructures has become an attractive research direction. By designing them as core-shell structures with different dimensions, the combined effects, such as interfacial polarization, conduction networks, magnetic coupling, and magnetic-dielectric synergy, can significantly enhance the EM wave absorption performance. Herein, the advances in low-dimensional core-shell EM wave absorption materials are outlined and a selection of the most remarkable examples is discussed. The derived key information regarding dimensional design, structural engineering, performance, and structure-function relationship are comprehensively summarized. Moreover, the investigation of the cutting-edge mechanisms is given particular attention. Additional applications, such as oxidation resistance and self-cleaning functions, are also introduced. Finally, insight into what may be expected from this rapidly expanding field and future challenges are presented.

Hierarchical engineering of Large-caliber carbon Nanotube/Mesoporous Carbon/Fe3C nanoparticle hybrid nanocomposite towards Ultra-lightweight electromagnetic microwave absorber

The rational regulation of the magnetic-dielectric composition and microstructures of the absorber is considered an important approach to optimize both the impedance matching and the electromagnetic microwave attenuation ability. Along these lines, a novel architecture-controlled large-caliber carbon nanotube/mesoporous carbon/Fe₃C nanoparticle-based hybrid nanocomposites (CNT/C/Fe₃C), which were derived from the CNT/polyimide (PI) assemblies anchoring ferric oxide hydrate nanoprecipitates, are presented in this work. The proposed configurations were prepared by applying a cooperative co-assembly strategy and high-temperature pyrolysis procedure for the development of an ultra-lightweight electromagnetic microwave absorber. The employed hierarchically tubular heterogeneous architecture is composed of a highly graphited CNT supporting skeleton, polyimide assemblies-converted carbon interlayer with mesopores, and uniformly distributed magnetic Fe₃C nanoparticles. This unique hierarchical structure can not only induce multiple reflection and scattering effects of the incident electromagnetic microwave but also trigger dipole/interfacial polarization, ferromagnetic resonance and eddy current loss that are beneficial for the synergistic dielectric and magnetic loss. Moreover, the large-caliber CNT and mesoporous carbon interlayer can endow the as-prepared absorber with lightweight characteristics. Hence, the proposed CNT/C-EDA/Fe₃C-900 hybrid nanocomposite exhibits a minimum reflection loss (RL) of -48.4 dB at a matching thickness of 3.2 mm, and the effective absorption bandwidth (RL ≤ -10 dB) almost covers the whole X-band only with a 5 wt% filler loading. Undoubtedly, these encouraging outcomes will promote the development of hierarchical engineering techniques of novel magnetic-dielectric nanocomposite absorbers.

Ni Flower/MXene-Melamine Foam Derived 3D Magnetic/Conductive Networks for Ultra-Efficient Microwave Absorption and Infrared Stealth

The development of multifunctional and efficient electromagnetic wave absorbing materials is a challenging research hotspot. Here, the magnetized Ni flower/MXene hybrids are successfully assembled on the surface of melamine foam (MF) through electrostatic self-assembly and dip-coating adsorption process, realizing the integration of microwave absorption, infrared stealth, and flame retardant. Remarkably, the Ni/MXene-MF achieves a minimum reflection loss (RL_min) of - 62.7 dB with a corresponding effective absorption bandwidth (EAB) of 6.24 GHz at 2 mm and an EAB of 6.88 GHz at 1.8 mm. Strong electromagnetic wave absorption is attributed to the three-dimensional magnetic/conductive networks, which provided excellent impedance matching, dielectric loss, magnetic loss, interface polarization, and multiple attenuations. In addition, the Ni/MXene-MF endows low density, excellent heat insulation, infrared stealth, and flame-retardant functions. This work provided a new development strategy for the design of multifunctional and efficient electromagnetic wave absorbing materials.

Magnetic modulation of core@shell MoS2-based flower-like multicomponent nanocomposites to improve microwave attenuation

Nanocomposites with a three-dimensional (3D) flower-like geometrical morphology were considered as excellent microwave absorbers (MAs) because of the numerous effective sites for the multiple reflections of electromagnetic (EM) wave. Herein, for optimizing the EM matching characteristic and taking full advantage of interface polarization, a strategy of magnetic modulation was proposed to further improve the EM wave absorption performances (EMWAPs) of MoS₂-based nanocomposites. We adopted a simple hydrothermal route and a combined method of hydrothermal treatment/hydrogen reduction to synthesize core@shell CoFe₂O₄@MoS₂ and CoFe@MoO₂/MoS₂ flower-like nanocomposites, respectively. The obtained results indicated that the hydrogen reduction effectively improved their magnetic properties and magnetic loss capabilities, and their 3D flower-like geometrical morphologies were well maintained during the hydrogen reduction process. The obtained core@shell CoFe@MoO₂/MoS₂ flower-like nanocomposites presented the extraordinary comprehensive EMWAPs including the optimal reflection loss value of -54.83 dB with the matching thicknesses (d_m) value of 2.05 mm and effective absorption bandwidth value of 6.40 GHz with the d_m value of 2.59 mm, which were evidently superior to the properties of CoFe₂O₄@MoS₂. Therefore, the findings provided an effective pathway to further improve EMWAPs of MoS₂-based core@shell nanocomposites and the as-prepared core@shell CoFe@MoO₂/MoS₂ flower-like nanocomposites could be utilized as the novel high-efficient MAs.

Synergetic Dielectric and Magnetic Losses of a Core-Shell Co/MnO/C Nanocomplex toward Highly Efficient Microwave Absorption

High-performance microwave-absorbing materials (MAMs) derived from metal-organic frameworks (MOFs) have attracted considerable attention due to their tunable chemical composition and microstructure. In this contribution, a core-shell-structured Co/MnO/C nanocomplex was prepared using a CoMn-MIL MOF by a facile hydrothermal synthesis and subsequent pyrolysis process. The optimal microwave absorption (MA) property of the as-prepared Co/MnO/C nanocomplex was achieved by the regulation of the Co²⁺/Mn²⁺ molar ratio. The minimum reflection loss (RL_min) of the Co/MnO/C-31 nanocomplex was low to -55.0 dB at 16.2 GHz with a thickness of 1.49 mm, and the effective absorption bandwidth (EAB) was high to 5.95 GHz (12.05-18 GHz) at a thickness of 1.8 mm. The mixed-metal nanocomplex with the core-shell structure exhibited outstanding MA performance, corresponding to the synergetic effect of the magnetic and dielectric loss. It provides a high efficiency strategy for rendering low reflection loss and broad EAB to high-performance MAMs.

Numerical analysis, experimental verification and criterion establishment of non-magnetic microwave absorbing material

Non-magnetic materials show a great potentiality in microwave absorption with the advantages of low-density, wideband, and thin thickness. Even so, it is still difficult to accurately analyze the connection between performance and parameters. To reveal what electromagnetic parameters could lead to excellent absorbing performance, we simplify and derive the formulae based on Transmission-Reflection-Line theory (TRL) and computer programs. Based on the relation of ε' and ε'', a criterion is established to decide what parameters have the possibility of absorbing performance. Using a new fitting method, the relationship between dielectric constant and absorber content is established. Further, an instruction derived from the relation between ε' and p is used to screen thicknesses. The optimum permittivity of ultra-low reflectivity and ultra-wide band is obtained by combining the numerical analysis results. To verify the accuracy and reliability of results and deductions, the permittivity of four prepared materials and fifty published papers are investigated.

High Performance Microwave Absorption of Lightweight and Porous Non-carbon-based Polymeric Monoliths via Gel Emulsion Template

A special porous non-carbon-based microwave-absorbing materials are designed and synthesized by bonding di(prop-1-en-2-yl) ferrocene into porous polymeric monoliths made by gel-emulsions as templates. In this study, a sequence of porous...

Bio-Inspired Microwave Modulator for High-Temperature Electromagnetic Protection, Infrared Stealth and Operating Temperature Monitoring

High-temperature electromagnetic (EM) protection materials integrated of multiple EM protection mechanisms and functions are regarded as desirable candidates for solving EM interference over a wide temperature range. In this work, a novel microwave modulator is fabricated by introducing carbonyl iron particles (CIP)/resin into channels of carbonized wood (C-wood). Innovatively, the spaced arrangement of two microwave absorbents not only achieves a synergistic enhancement of magnetic and dielectric losses, but also breaks the translational invariance of EM characteristics in the horizontal direction to obtain multiple phase discontinuities in the frequency range of 8.2-18.0 GHz achieving modulation of reflected wave radiation direction. Accordingly, CIP/C-wood microwave modulator demonstrates the maximum effective bandwidth of 5.2 GHz and the maximum EM protection efficiency over 97% with a thickness of only 1.5 mm in the temperature range 298-673 K. Besides, CIP/C-wood microwave modulator shows stable and low thermal conductivities, as well as monotonic electrical conductivity-temperature characteristics, therefore it can also achieve thermal infrared stealth and working temperature monitoring in wide temperature ranges. This work provides an inspiration for the design of high-temperature EM protection materials with multiple EM protection mechanisms and functions.

In Situ Dual-Template Method of Synthesis of Inverse-Opal Co3O4@TiO2 with Wideband Microwave Absorption

A unique porous TiO₂ with Co₃O₄ nanoparticles anchored in (Co₃O₄@TiO₂) is prepared by a dual-templating method for promoting electromagnetic microwave absorption (EMA). The as-prepared Co₃O₄@TiO₂ possesses a three-dimensional (3D) ordered macroporous TiO₂ skeleton and plenty of mesopores, as well as small Co₃O₄ nanoparticles that coexisted in the macropore walls of the TiO₂ skeleton. The introduction of Co₃O₄ can increase the magnetic loss as well as suppress impedance mismatch, resulting in the regulation of the EMA performance. The synergetic effect of the TiO₂ porous framework and Co₃O₄ nanoparticles with proper ratio promote microwave absorption performance. Therefore, Co₃O₄@TiO₂-2 with 25 wt % Co₃O₄ nanoparticles content displays a strong and ultrawide effective absorption band (EAB) performance. The Co₃O₄@TiO₂-2 presents a strong reflection loss of -53.9 dB at 2.95 mm. Moreover, it obtains a super broad EAB of ∼12.5 GHz at 5.0 mm. This dual-templating approach for a well-controlled porous structure could be a facial strategy for the development of high-performance electromagnetic wave absorbers.

Conductive substrates-based component tailoring via thermal conversion of metal organic framework for enhanced microwave absorption performances

Component tailoring, especially for the conductive substrates-based composites, acts as a significant role in optimizing the electromagnetic (EM) parameters and improving the EM response capability. Here, Fe-based metal oxides modified rGO microwave absorbers with component evolution were fabricated through hydrothermal treatment and subsequent pyrolysis process. The synergistic effects of the dielectric loss (multi-relaxations) and the magnetic loss (resonance and eddy current) are found to be effective in promoting the microwave absorption property of Fe_x-1O_x/C/rGO absorbers. As the thermal treatment temperature reaches 500 °C, the as-prepared composite sample shows ideal microwave absorption performance, where the reflection loss value is -25.94 dB, and the effective bandwidth reaches 5.84 GHz at 1.9 mm. In addition, CST simulation was employed to analyze the microwave absorption capability in the actual far field. When the scattering angle is 0° and 20°, the radar cross section (RCS) reduction of S-500/PEC layers is 8.11 dB m² and 8.80 dB m², respectively. This study exhibits the importance of component tailoring in enhancing the performances of substrates-based microwave absorption materials.

High-Performance, Lightweight, and Flexible Thermoplastic Polyurethane Nanocomposites with Zn2+-Substituted CoFe2O4 Nanoparticles and Reduced Graphene Oxide as Shielding Materials against Electromagnetic Pollution

The development of flexible, lightweight, and thin high-performance electromagnetic interference shielding materials is urgently needed for the protection of humans, the environment, and electronic devices against electromagnetic radiation. To achieve this, the spinel ferrite nanoparticles CoFe2O4 (CZ1), Co0.67Zn0.33Fe2O4 (CZ2), and Co0.33Zn0.67Fe2O4 (CZ3) were prepared by the sonochemical synthesis method. Further, these prepared spinel ferrite nanoparticles and reduced graphene oxide (rGO) were embedded in a thermoplastic polyurethane (TPU) matrix. The maximum electromagnetic interference (EMI) total shielding effectiveness (SET) values in the frequency range 8.2-12.4 GHz of these nanocomposites with a thickness of only 0.8 mm were 48.3, 61.8, and 67.8 dB for CZ1-rGO-TPU, CZ2-rGO-TPU, and CZ3-rGO-TPU, respectively. The high-performance electromagnetic interference shielding characteristics of the CZ3-rGO-TPU nanocomposite stem from dipole and interfacial polarization, conduction loss, multiple scattering, eddy current effect, natural resonance, high attenuation constant, and impedance matching. The optimized CZ3-rGO-TPU nanocomposite can be a potential candidate as a lightweight, flexible, thin, and high-performance electromagnetic interference shielding material.

Nitrogen-Doped Ti3C2Tx MXene Induced by Plasma Treatment with Enhanced Microwave Absorption Properties

Ti₃C₂T_x has microwave absorption (MA) properties due to its dielectric loss, but the absence of magnetic loss capability of pure Ti₃C₂T_x causes unmatched impedance and unsatisfied MA performance. Modification of Ti₃C₂T_x with magnetic particles is an effective way to introduce the magnetic loss mechanism. However, these modified Ti₃C₂T_x particles have higher density and require complicated fabrication processes, restricting the industrial production and functional applications. Here, a low-temperature and simple method of radio-frequency N₂ plasma treatment was adopted to modify Ti₃C₂T_x with N. More interestingly, the N-doped Ti₃C₂T_x flakes demonstrated magnetic properties and thus exhibited drastically enhanced MA properties. The minimum reflection loss (RL_min) of -59.20 dB at 10.56 GHz was achieved in N-doped Ti₃C₂T_x products after only 3 min of plasma treatment, remarkably higher than RL_min of -11.07 dB at 7.92 GHz for the pristine Ti₃C₂T_x. The main mechanism is due to the combination of dielectric loss, magnetic loss, and the good impedance matching in the N-doped Ti₃C₂T_x. Further prolonging the nitriding time induces much desorption of -F and the formation of TiO₂, thus deteriorating the impedance matching and the MA properties.

Tuning Dielectric Loss of SiO2@CNTs for Electromagnetic Wave Absorption

We developed a simple method to fabricate SiO₂-sphere-supported N-doped CNTs (NCNTs) for electromagnetic wave (EMW) absorption. EMW absorption was tuned by adsorption of the organic agent on the precursor of the catalysts. The experimental results show that the conductivity loss and polarization loss of the sample are improved. Meanwhile, the impedance matching characteristics can also be adjusted. When the matching thickness was only 1.5 mm, the optimal 3D structure shows excellent EMW absorption performance, which is better than most magnetic carbon matrix composites. Our current approach opens up an effective way to develop low-cost, high-performance EMW absorbers.

Opportunities and challenges in microwave absorption of nickel-carbon composites

In recent years, the problem of electromagnetic wave (EMW) pollution has attracted more and more attention with the development of science and technology. In order to solve this complex problem, the research and development of EMW-absorbing materials is crucial. The new absorbing materials should have the characteristics of light weight, high efficiency, wide bandwidth, environmental protection, oxidation resistance, and other characteristics. Traditional single-phase Ni materials exhibit remarkable ferromagnetic behavior and double-loss mechanisms (dielectric loss and magnetic loss), and are considered as efficient EMW absorbers. However, under the action of EMWs, especially in the GHz frequency band, Ni materials tend to produce an eddy current effect, which limits their application prospects. For Ni-based materials, there is much interest in modifying the composite materials by designing a hierarchical structure for their preparation. Traditional, single-phase, carbon-based materials have been widely used in related fields because of their light weight and good conductivity. However, a single-loss mechanism will affect the impedance matching of carbon materials, thus affecting their application in the field of absorbing waves. For carbon materials, people use them as a filler or matrix material to fabricate composites with metals, metal oxides, or polymer materials to obtain carbon-containing absorbing materials. This paper reviews the evaluation and design principles of the absorbing properties of EMW-absorbing materials. Then, the progress of modified single-phase Ni-based materials (designed materials with 0D, 1D, 2D, and 3D structures), the development of carbon materials (carbon black, carbon nanotubes, carbon fiber, graphite oxide, reduced graphene oxide, and biomedical carbon), and the research progress of Ni-C composite materials (the composite material formed by nickel and carbon) are reviewed. The ultimate goal is to obtain absorbers with light weight, strong absorbing ability, and a wide frequency band. In particular, Ni-MXene, Ni-biomedical carbon, and Ni-multiphase carbon composites are the target direction for designing new and high efficiency EMW absorbers. Finally, the basic challenges and opportunities in this field are discussed.

Rational construction of porous N-doped Fe2O3 films on porous graphene foams by molecular layer deposition for tunable microwave absorption

Graphene-based materials with porous microstructure have attracted immense attentions due to their wide application in microwave absorption. However, constructing magnetic film with both porous microstructure and uniform pore size by using traditional methods still remains a challenge. To overcome this problem, we reported a facile strategy of molecular layer deposition (MLD) for successfully fabrication of the hybrid-architecture of porous graphene foams and nitrogen-doped porous Fe₂O₃ films. The surfaces of porous graphene foams are uniformly covered by porous Fe₂O₃ films without aggregation and the pore structures are widely distributed. The porous graphene-based composites exhibit remarkably enhanced microwave absorption performance compared to the pristine graphene foams. The minimum reflection loss value is increased by approximately 8 times, reaching -64.36 dB with a thickness of only 2.18 mm. More importantly, the absorption property can be precisely modulated by tuning the MLD cycle numbers and effective absorption bandwidth covers 3.04-18.0 GHz by adjusting the thickness from 1.0 to 5.0 mm. This work provides new insights for exploring novel and high-performance graphene-based microwave absorbents and offers a new idea to rationally design three-dimensional composites with porous magnetic films.

Effective lightweight, flexible and ultrathin PVDF/rGO/Ba2Co2Fe12O22composite films for electromagnetic interference shielding applications

In this study, we developed a simple and cost-effective solvent film casting method to fabricate ultrathin, flexible and lightweight polyvinylidenefluoride (PVDF)-based composites that provide high electromagnetic interference (EMI) shielding performance. Y-type barium hexaferrite with general formula Ba₂Co₂Fe₁₂O₂₂was first synthesized by the sol-gel autocombustion method and then reduced graphene oxide (rGO) was prepared by modified Hummer's method. The crystal structure, morphology, elemental surface analysis and magnetic properties of the samples were systematically investigated using x-ray diffraction spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, high-resolution scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy and vibrating sample magnetometry. Then, the complex permittivity, complex permeability and EMI shielding properties of the flexible PVDF/rGO/Ba₂Co₂Fe₁₂O₂₂composite films with two different amounts of Ba₂Co₂Fe₁₂O₂₂NP content and a fixed amount of rGO content were investigated using a vector network analyzer. The structural characterizations of the resultant composite films showed the formation of an electroactiveβ-phase of PVDF with addition of Ba₂Co₂Fe₁₂O₂₂nanoparticles and rGO content. The enhancement of theβ-phase in the PVDF/rGO/Ba₂Co₂Fe₁₂O₂₂nanocomposites was explained from a physicochemical viewpoint. Furthermore, the electrically conductive and magnetic properties of PVDF composite films incorporating rGO and Ba₂Co₂Fe₁₂O₂₂NPs exhibited a high EMI shielding effectiveness of 25.63 dB, with an absorption-dominated shielding feature in the 8-12 GHz region. The enhanced absorption was attributed to the electrostatic interaction induced by theβ-phase fraction in the PVDF matrix, and subsequently from multiple reflections and magnetic loss originating from the synergetic effect of rGO and Ba₂Co₂Fe₁₂O₂₂NPs. This study introduces a low-cost and scalable method for the design of novel, lightweight, flexible and efficient EMI shielding composite films with promising prospects for application in the construction, electronics and aerospace fields.

Cubic-like Co/NC composites derived from ZIF-67 with a dual control strategy of size and graphitization degree for microwave absorption

MOFs with high tunability are considered ideal candidates as microwave-absorbing materials. Strict experimental conditions can ensure the repeatability and maximize the potential of such materials. In this study, cubic ZIF-67 carbides synthesized at different solution temperatures showed an adjustable average size, and then by adjusting the calcination temperature we could control the degree of graphitization, so as to explore the synergistic effect of these two aspects to achieve an in-depth understanding of the electromagnetic properties and microwave absorption properties. The results showed that sample 30-600 (with the former number referring to the synthesis temperature and the latter to the calcination temperature) showed the widest effective absorption bandwidth (5.75 GHz, 1.8 mm) and the optimal reflection loss (-56.92 dB, 2.1 mm). The best matching electromagnetic parameters were obtained under the synergistic action of a smaller particle size and appropriate degree of graphitization, so as to achieve strong attenuation characteristics under low electromagnetic wave reflection. The microwave loss mechanism of the sample mainly involved dielectric losses, such as from conductance loss, dipole polarization, and interface polarization. Starting from the experimental details, this work proposes a dual control strategy for developing microwave-absorbing materials with both simplicity and practicability, which provides a useful reference for other microwave absorbents synthesized at room temperature.

Metal-Organic Framework-Derived Carbon/Carbon Nanotubes Mediate Impedance Matching for Strong Microwave Absorption at Fairly Low Temperatures

The use of magnetic particles and carbon materials, particularly those with compatible dielectric and magnetic loss, is crucial in managing microwave pollution. However, the mismatched impedance of currently available absorbers constrains their practical applications. Herein, we demonstrate the potential of a metal-organic framework (MOF)-derived composite whose impedance matching is optimized through spraying and immersion of MOF precursors in carbon nanotube socks followed by carbonization. The composite presents extremely strong microwave absorption with a reflection loss of -30 dB, a thin thickness of 1.5 mm, and a wide frequency bandwidth of 7.8 GHz. The excellent absorption can still be maintained even at a fairly low temperature of -40 °C. Such results are primarily attributed to the synergistic effect between the hierarchical architecture and multiple components that greatly optimizes the impedance matching. We believe that the composite is a promising microwave absorber that can help to solve the critical electromagnetic wave pollution.

Confined Magnetic-Dielectric Balance Boosted Electromagnetic Wave Absorption

Magnetic-dielectric property plays a critical significance for the functional expression toward advanced materials. Within nanoscale, the simultaneous regulation of the electrical and magnetic properties of electromagnetic (EM) wave absorption materials faces huge challenges. Herein, using the metal-organic frameworks (MOF) as templates, highly-dispersed ZnO and Co nanoparticles are uniformly confined inside graphited N-doped carbon skeleton, constructing the balanced EM property in the Co@NC-ZnO absorbers. Meanwhile, a dynamics and symmetrical morphology optimization of MOF-derived Co@NC-ZnO are dependent on the Co/Zn mass ratio and adjusting MOF frameworks, which evolves from the cube, truncated cube, dodecahedron, and to the final microsphere. Simultaneously, both the electronic conduction network and magnetic coupling network are compatible together in the in situ transformed Co@NC-ZnO system. Boosted magnetic responding ability and unique magnetic coupling are verified by the off-axis electronic holography. Plentiful heterojunction interfaces and special electronic conduction paths can be built in this Co-Zn-MOF derivatives, facilitating the dielectric loss behaviors. As expected, MOF-derived Co@NC-ZnO absorber displays outstanding EM wave absorption ability with strongest reflection loss value of -69.6 dB at only 1.9 mm thickness and wideband absorption covering 6.8 GHz at 2.4 mm. Confined EM balance provides new design strategy toward MOF-derived excellent MA materials and functional devices.

Defect-Enhanced Electromagnetic Wave Absorption Property of Hierarchical Graphite Capsules@Helical Carbon Nanotube Hybrid Nanocomposites

Development of high-performance materials for electromagnetic wave absorption has attracted extensive interest, but it still remains a huge challenge especially in reducing density and lowering filler loading. Herein, a hierarchical all-carbon nanostructure is rationally designed as follows: the defect-rich hollow graphite capsules (GCs) controlled by the size/density of ZnO templates are synthesized on the surface of helical carbon nanotubes (HCNTs) to form a hybrid nanocomposite, denoted as GCs@HCNTs. As a result, the GCs@HCNTs demonstrate a strong and wide absorption performance with a very low filler loading of 10 wt %. The minimum reflection loss reaches -51.7 dB at 7.6 GHz, and the effective bandwidth (below -10 dB) ranges from 8 to 14 GHz, covering the whole X or Ku bands. The hierarchical nanostructure and homoatomic heterogeneous interface are beneficial to impedance matching and bring additional dipole polarization enhanced by the structural defects, which may enlighten the design of ultralight and broadband high-performance electromagnetic wave absorption materials.

Melamine-induced formation of carbon nanotubes assembly on metal-organic framework-derived Co/C composites for lightweight and broadband microwave absorption

Extending effective absorption bandwidth at a low filling ratio is still a challenge for metal-organic framework-derived microwave absorbing materials. Herein, varied complex structures based on CNTs have been built on Co/C particles derived from ZIF-67 via melamine-involved annealing routes. It was found that cobalt nanoparticles derived from ZIF-67 act as catalysts for the growth of CNTs, effectively promoting and controlling the content of melamine. Due to the effective control of the CNT-containing complex structure, excellent microwave absorption performance was achieved at a rather low filling ratio of 20 wt%, which can be attributed to improved attenuation ability and ameliorated impedance matching. Results show that highly graphitic CNTs benefit the formation of the electron transport network and enhancement of conduction loss. Unique one-dimensional complex structure and abundant Co/C interfaces strengthen the polarization loss. When the dielectric loss was optimized at different frequencies, appropriate impedance matching was also gained to realize a broad effective absorption bandwidth of 5.6 and 4.4 GHz in Ku and X bands, respectively. This work may provide novel insights into the synthesis and design of CNT-containing metal-organic framework-derived materials with lightweight features and wide frequency response.

Alternating Multilayered Si3N4/SiC Aerogels for Broadband and High-Temperature Electromagnetic Wave Absorption up to 1000 °C

Lightweight electromagnetic (EM) wave absorbers made of ceramics have sparked tremendous interest for applications in EM wave interference protection at high temperatures. However, EM wave absorption by pure ceramics still faces huge challenges due to the lack of efficient EM wave attenuation modes. Inspired by the energy dissipation mechanism during fracture of lobster shells with a soft and stiff multilayered structure, we fabricate a high-performance EM wave absorption ceramic aerogel composed of an alternating multilayered wave transparent Si₃N₄ (N) layer and wave absorption SiC (C) layer by a simple restack method. The obtained N/C aerogel shows ultralow density (∼8 mg/cm³), broad effective absorption bandwidth (8.4 GHz), strong reflection loss (-45 dB) at room temperature, and excellent EM wave absorption performance at high temperatures up to 1000 °C. The attenuation of EM wave mainly results from a "reflection-absorption-zigzag reflection" process caused by the alternating multilayered structure. The superior absorption performance, especially at high temperatures, makes the N/C aerogel promising for next-generation wave absorption devices served in high-temperature environments.