The three-dimensional hollow structural design combined with component regulation has been recognized as an effective strategy for achieving lightweight, broadband microwave absorption. Herein, nitrogen-doped hollow carbon microcubes modified with in situ catalytic growth carbon nanotubes (Ni@CNTs/N-HCMs) were successfully fabricated using a salt-template technique followed by a subsequent chemical-catalyzed self-deposition (CCSD) process and a simple water-washing step for template removal. Benefiting from the unique structural features improving the impedance matching and the synergistic effect of multiple components enhancing loss capacity, the microwave absorption performance of the as-obtained Ni@CNTs/N-HCMs composites could be effectively regulated and optimized. Remarkably, with a filling loading of only 3.5 wt%, the optimal reflection loss can reach up to -46.7 dB at 3.7 mm and the maximum effective absorption bandwidth attains 6.1 GHz at 2.0 mm, respectively. Importantly, the salt templates are more economical and environmentally friendly, and the salt templates offer the potential for recycling, facilitating large-scale production of the material. This study provides an innovative path for constructing high-performance functional carbon-based microwave absorption materials.

Recognized as a critical environmental hazard in modern industry, electromagnetic radiation poses substantial risks to human health and the ecosystem, necessitating lightweight and broadband microwave absorption materials as essential components of electromagnetic safety strategies. This work demonstrates a hollow engineering strategy for magnetic graphene composites, wherein centrifugal spray drying combined with subsequent high-temperature pyrolysis yields graphene hollow microspheres with magnetic nanoparticles uniformly anchored onto their inner and outer walls. The influence of pyrolysis temperature on the microwave absorption properties of the resulting composites is systematically investigated. Experimental results reveal that the pyrolysis temperature critically governs the phase crystallinity, graphitization degree and magnetic characteristics, thereby determining both their dielectric loss and magnetic loss capacities as well as the impedance matching behavior. An optimal pyrolysis temperature (800 ℃) yields superior broadband microwave absorption, achieving a minimum reflection loss (RLmin) of -45.3 dB and an effective absorption bandwidth (EAB, RL<-10 dB) exceeding 5.8 GHz at a thin thickness of 1.82 mm. The exceptional performance is attributed to the synergistic interplay of multiple attenuation mechanisms, including dielectric loss from the defective rGO and hollow cavity-induced multiple reflections, magnetic loss from the embedded nanoparticles, and enhanced impedance matching enabled by the hollow architecture. These findings advance the understanding of pyrolysis-temperature effects on microwave absorption and establish a promising platform for hollow-structure engineering.

As the issue of electromagnetic pollution continues to intensify, the design of high-performance microwave absorption materials featuring lightweight, broad bandwidth and strong absorption has become a key research focus. In this work, we propose a strategic integration of electrospinning technology and melamine-assisted chemical vapor deposition (CVD) to construct carbon nanotube (CNT)-bridged polymer-derived carbon nano-fiber (PCNF) composites (denoted as CNTs/M@PCNFs). In this architecture, CNTs effectively bridge adjacent PCNFs, forming an interconnected conductive network. The resulting composites exhibit significantly enhanced dielectric loss capability due to the improved conductivity, interfacial polarization, and multiple scattering. Furthermore, nitrogen doping derived from melamine introduces additional dipole polarization and optimizes impedance matching. Consequently, the composites achieve excellent microwave absorption performance, with a low filler loading of only 10 wt%, a strong minimum reflection loss of-39.8 dB, and a broad effective absorption bandwidth of 7.85 GHz. This work offers a new avenue for developing high-performance microwave absorption materials.

To improve the interfacial bonding strength between T800 carbon fibers (CF) and polyimide resin, this study employed O2-Ar mixed gas plasma for modification treatment of the CF. In this study, the gas flow rates were controlled to indirectly regulate the gas ratio, and O2-Ar mixed-gas component experiments were conducted. The optimal O2-Ar mixing ratio was determined to be 5:5. Based on this optimal ratio, orthogonal experiments were carried out to determine the optimal treatment conditions under O2-Ar mixed-gas plasma. Under optimal treatment conditions, both the room-temperature and high-temperature interlaminar shear strength (ILSS) of the composites were significantly improved. The room-temperature ILSS increased from 100.89 to 124.75 MPa, corresponding to an enhancement of 23.6%; while the ILSS at 300 degrees C increased from 69.98 to 97.42 MPa, representing an improvement of 39.2%. By combining objective evidence from microscopic characterization, carbon fiber contact angle and surface energy data, mechanical property data, and the cross-section of the composite after failure, the synergistic mechanism of the O2-Ar mixed gas was elucidated, providing ideas and methods that can serve as a reference for subsequent research on multi-component mixed gases.

Although silicon is a promising anode material for lithium-ion batteries, efficient and controllable synthesis of silicon anodes with good cyclability and low electrode swelling remains a major challenge. Here, we have synthesized a novel bread-like Si/C composite with a yolk-double shell structure through sol-gel and self-template methods. In this design, the zeolite imidazolate framework-derived nitrogen-doped porous carbon skeleton is applied to enhance the electrical conductivity of silicon, and the adequate space inside the yolk-double shell structure can effectively mitigate the volume change of silicon. Additionally, porous structures are not only conducive to the rapid diffusion of the electrolyte but also shorten the migration channel of lithium ions and electrons. The stable bread-like double carbon layer structure helps in the formation of stable solid electrolyte interphase films. As expected, the composite demonstrates exceptional electrochemical properties, including outstanding reversible capacity (868.1 mA h g-1 after 500 extended cycles at 1 A g-1) and remarkable rate capability (408.1 mA h g-1 at a high current density of 5 A g-1). Moreover, the anode has a low electrode expansion rate of 31% after cycling. This study provides a new idea for designing high-stability silicon-based anode materials.

The deformation process of helical structure is analogous to the stretching of spring which has shape memory capability. We propose introducing helical structure molecules into thermosetting resin matrix to investigate the influence of helical structure molecules on the shape memory properties of the resin matrix. The effects of helical structure on the thermomechanical properties and shape memory properties of epoxy and bismaleimide resins were analyzed by molecular dynamics. The results indicated that the introduction of helical structure molecules could enhance the tensile properties of thermosetting resin crosslinking network to some extent, and also reduce residual strain in the network. The epoxy resin and bismaleimide resin cell both contain one helical molecule, with mass fractions of 6.15% and 5.95%, respectively. The introduction of one helical structure additionally enhanced the shape memory recovery ratio of epoxy resin and bismaleimide resin by 12.63% and 12.76%, respectively, while promoting a faster shape recovery response in the crosslinking network.

The rational structural design and precise compositional regulation of lightweight and broadband carbon-based absorbing materials is an urgent task at present to deal with the complex electromagnetic environment. The soluble salt template assisted preparation technology holds good feasibility for constructing unique hollow carbon-based microwave absorbents due to their reusability and economy of salt templates. Nevertheless, magnetic modified nitrogen doping hollow carbon microcapsules fabricated by employing salt-template technique have not been explored. Herein, we adopt a green and low cost NaCl soluble salt template assisted synthesis strategy to universally fabricate 3D unique hollow carbon-based microwave materials loaded with precursors of magnetic particles. Following the high-temperature pyrolysis and wash desalting template, we have successfully achieved mass preparation of magnetic modified nitrogen doping hollow carbon microcapsules. Benefiting from the unique chemical component dominance and distinctive structural merits, the optimized Ni magnetic modified nitrogen doping hollow carbon microcapsules (Ni@N-HCNs) delivered extremely outstanding microwave absorption performance (MAP), including an optimal minimum reflection loss value (RLmin) of -37.7 dB and an effective absorption bandwidth of 5.5 GHz under a filling level of only 5 wt%. More excitingly, the widest effective absorption bandwidth could cover up to 7.87 GHz (10.03-18.0 GHz) at a thin matching thickness of 2.6 mm. Due to the large-scale production and simple preparation process, Ni@N-HCNs composites might be considered as one of the most competitive candidates for the design of lightweight and high performance microwave absorbents.

Microwave-absorbing materials play a pivotal role in electromagnetic protection and military stealth applications. Core-shell structured materials are expected to be candidates for advanced electromagnetic wave absorption materials due to their unique ability to optimize interface polarization and impedance matching. A coreshell CoxNiy@SiO2@C (CNSC) nanocomposite was prepared via modified Stober process and in-situ polymerization method. At a matching thickness of 2.5 mm, the CNSC-0.5 composite demonstrates exceptional microwave absorption performance, achieving a minimum reflection loss of -61.31 dB at 14.43 GHz and an effective absorption bandwidth) of 6.63 GHz, covering a significant portion of the Ku-band (12-18 GHz). This study presents a promising synthesis strategy for developing high-performance broadband microwave absorbers through rational structural design and multicomponent integration.

One-dimensional dielectric-magnetic heterostructures demonstrate significant potential in microwave absorption beyond traditional single-component materials, owing to their unique electromagnetic coupling properties. This study innovatively presents a synergistic strategy of in-situ oxidative polymerization and topologically confined pyrolysis to construct nitrogen-doped carbon/cobalt/polypyrrole coaxial nanotubes (NC/Co/PPy NTs) with multi-scale heterogeneous interfaces. The designed structure featured Co nanoparticles sandwiched between dual conductive layers, forming a sandwich-like configuration that not only established a percolating conductive network but also effectively suppressed the agglomeration of magnetic nanoparticles. Characterization results indicated that the gradient distribution of dielectric-magnetic components and the multi-shell hollow structure synergistically optimized impedance matching, while the interfacial polarization induced by multiple heterogeneous interfaces significantly enhanced electromagnetic wave loss capability. Benefiting from the precise microscopic structure design and multi-mechanism synergistic loss effects, the as-prepared NC/Co/PPy NTs exhibited exceptional microwave absorption performance, achieving a minimum reflection loss of-63.98 dB at 8.14 GHz with an effective absorption bandwidth covering 7.14 GHz. Moreover, the material demonstrated good thermal insulation properties, offering potential for integrated applications in thermal management and electromagnetic protection. By constructing multi-scale dielectric-magnetic heterointerfaces, this work offers new insights for developing lightweight, broadband, and multifunctional microwave absorption materials.

The rational construction of multi-component heterogeneous interfaces is crucial for overcoming the inherent limitations of single-component microwave absorbers. This study designs a novel multi-component composite Ti3C2Tx-TiO2/nitrogen-doped carbon derived from MXene@polypyrrole. By employing an in situ polymerization-calcination temperature gradient design method, the oxidation degree of the MXene precursor and the carbonization process are precisely controlled, thereby adjusting the dielectric constant. The optimized composite exhibits excellent microwave absorption performance, achieving an effective absorption bandwidth (EAB, RL ≤-10 dB) of 6.89 GHz and a strong reflection loss of -57.27 dB at a thickness of 2.2 mm. Mechanistic studies reveal that excellent impedance matching and multiple polarization between multi-layer heterogeneous interfaces cooperate to establish a comprehensive microwave attenuation mechanism. Compared with the recently developed TiO2-based microwave absorbing materials, the EAB is significantly enhanced, successfully resolving the long-standing bandwidth-thickness contradiction in dielectric-dominant systems. Additionally, the thermal insulation property of the material makes it have the potential for practical application. This study provides new insights into the design of multifunctional electromagnetic wave absorbers.

The Ni/Beta zeolite has been recognized as a promising catalyst for olefin oligomerization, though its catalytic activity and stability still confront significant challenges. In this work, the alkaline/acid treatment is employed to inducibly regulate the acid center and cationic Ni coordination environment in hierarchical Ni/Beta catalysts. Notably, this modification modulates the framework Al species, transitioning them to an extra-framework state, which intensifies the electron deficiency of Ni cations and consequently boosts their catalytic activities. These cations in the modified sample, acting as active species, exhibit an elevated reaction rate of 182.1 molC3=/ (molNi & sdot;h), up from 151.3 molC3=/(molNi & sdot;h), while maintaining a dimer selectivity of 69.1 %. In addition, the optimally desilicated Ni/DSB(5.5) sample exhibits a larger mesoporous volume (0.943 cm3/g) compared to the untreated Ni/Beta(12) (0.734 cm3/g), facilitating faster product desorption and diffusion, ultimately prolonging catalyst lifetime. The generation of secondary mesopores significantly reduces the catalyst deactivation rate from 0.0663 h-1 to 0.0109 h-1 during operation. This strategy successfully enhances the catalytic activity and stability of Ni/Beta catalyst for propylene dimerization. The comparative analyses involving Al-containing and Al-free catalysts further underscore the crucial role of various Al states on the Ni active species. This study presents an approach for the development of highly efficient and long-term stable catalysts for olefin oligomerization.

Conductive polymers materials with hollow micro/nanostructure due to their special electrical properties and corrosion resistance have potential applications in microwave absorption, especially in marine environment. Herein, one-dimensional hollow conductive polypyrrole microtubes (H-PPyM) were prepared by in-situ polymerization of pyrrole monomer with methyl orange (MO) as soft template and FeCl3 as oxidant based on structural regulation strategy. The morphology and conductivity of H-PPyM can be easily controlled by adjusting the content proportion of MO. The results indicated that the surface morphology of polypyrrole changed from random granular to microtubular and the conductivity also gradually rose with the content increase of MO. When the content proportion of MO was 0.25 g, the obtained H-PPyM-0.25 composites possed notable microwave absorption capacity, simultaneously achieving ultrabroad effective absorption bandwidth (EAB, 6.7 GHz) and strong reflection loss value (RL, -33.6 dB) at a thickness of 2.6 mm with the filling content of only 10 wt.%, respectively. Furthermore, the corresponding H-PPyM-0.25 products soaked in corrosive medium (3.5 wt% NaCl solution) for one month still displayed stable tubular hollow structure and excellent microwave absorption performance with RLmin of -43.8 dB and EAB of 6.2 GHz. The research results can not only help to understand the relationship among the morphology and microwave absorption of PPy, but also open a new avenue for preparing excellent seawater corrosion resistant microwave absorption materials.

Amid escalating electromagnetic pollution, the urgent demand for advanced microwave absorbers exhibiting thin-profile, lightweight, strong attenuation, and broadband absorption characteristics has driven this research. Guided by polarization theory, we engineered the composition and morphology of MXene/MOF-derived composites through a rational design strategy. By integrating two-step etched MXene with dopamine-modified hollow ZIF-67 assemblies followed by controlled pyrolysis, Li4Ti5O12 was successfully intercalated within MXene interlayers, creating high surface area interfaces that significantly enhance interfacial polarization. Leveraging the tunable surface characteristics of MXene nanosheets and the compositional flexibility of MOF derivatives, the synthesized material achieves optimal magneto-dielectric balance. The resulting HCLT-3 composite demonstrates exceptional impedance matching and electromagnetic dissipation capabilities, delivering a minimal reflection loss of -58.97 dB at 2.26 mm thickness and an ultra-wide effective absorption bandwidth of 8.50 GHz. This work pioneers a dual-approach methodology combining conventional component hybridization with innovative 2D interlayer engineering-providing valuable insights for developing next generation high performance MXene-based microwave absorbers.

The narrow effective absorption band of manganese dioxide (MnO2) as dielectric loss material seriously limits their application in the field of electromagnetic functional materials. Morphology control engineering is one of the key strategies to modulate the electric structure and improve the electromagnetic loss ability. Herein, onedimensional manganese dioxide nanowires (alpha-MnO2 NW) were prepared by a controllable hydrothermal synthesis method. Interestingly, the morphology and crystal structure of manganese dioxide can be easily controlled by adjusting the proportion of manganese ions Mn2+/Mn7+. The results showed that with the increase of Mn7+, the surface morphology of MnO2 changed from nanowires to nanoflowers and the crystal structure also changed. When the molar ratio of Mn2+ to Mn7+ was 1:3, the manganese dioxide nanowires (alpha-MnO2 NW) possed notable microwave absorption performance, simultaneously achieving strong absorption characteristics at a thickness of 2.8 mm (-55.76 dB at 10.8 GHz) and ultrabroad absorption bandwidth (5.6 GHz) at a thin thickness of 2.1 mm with the filling content of 17.5 wt%, respectively. The research results can not only help to understand the relationship among the morphology, structure and microwave absorption of MnO2, but also help to realize the controllable synthesis of multi-morphology and multifunctional MnO2.

This paper examines surface modification of carbon fibers using low-temperature plasma and investigates the temperature-dependent interfacial properties of high-performance polyimide-based composites. Additionally, the mechanisms by which air and argon plasma treatments enhance the high-temperature interfacial properties of carbon fiber-reinforced polymers (CFRP) are examined. First, the changes in physical morphology and surface structural defects of carbon fibers under different plasma atmospheres are discussed: carbon fibers develop surface protrusions after various plasma treatments, and a grooved morphology forms after argon plasma treatment. The ID/IG ratio (R value) of the carbon fiber surface increased from 1.25 in untreated fibers to 1.37 after air plasma treatment, and further to 1.60 after argon plasma treatment. The short-beam shear strength test results show that at 300 degrees C, the ILSS (interlaminar shear strength) of argon plasma-treated laminates increased from 67.70 MPa to 87.69 MPa, a 29.53% improvement. The ILSS of air plasma-treated laminates reached 81.46 MPa, a 20.33% improvement. Argon plasma-treated laminates showed more stable interlaminar shear performance at high temperatures, maintaining an interfacial retention rate of 85.11% at 300 degrees C. Secondly, the mechanisms by which air and argon plasma modification enhance the high-temperature interface performance of CFRP are as follows: Air treatment, due to the dual effects of chemical bonding and physical etching, allows the laminated plates to exhibit excellent performance at room temperature. However, in high-temperature environments, the chemical bonding effect is easily affected and damaged, significantly reducing the interface retention rate of the laminated plates. The etching effect of argon treatment is quite significant, which means that the improvement effect of argon mainly manifests in the mechanical interlocking action, with the chemical bonding effect being relatively small. The physical effect of mechanical interlocking is less influenced by temperature, thus the high-temperature retention rate of the laminate is relatively high. Furthermore, molecular dynamics models of the interface were built using atomic simulation to explore how plasma modification introduces active groups that enhance the interface at the molecular level. The impact of these modifications on interfacial structure and energy was analyzed using molecular dynamics metrics. Both experimental and molecular dynamics simulation results confirm that plasma treatment has a positive regulatory effect on the interface.

The sustainable electromagnetic (EM) environment urgently needs the development of high-performance absorbers. This study involved synthesizing a series of ZnOCo@ND-CN (X) composites through in-situ depositing Prussian blue analogue (Zn3[Co(CN)6]2) on varying amounts of Nitrogen-Depleted g-C3N4 (ND-CN), followed by carbonization. Adjusting the amount of ND-CN in the composites can effectively regulate the dielectric constant. The as-fabricated defective structures with high electrical conductivity and the synergy between ND-CN with ZnOCo particles, as well as the presence of a variety of heterogeneous interfaces, which endow the composites with the impressive EM wave absorption properties. ZnOCo@ND-CN (0.2) simultaneously exhibits a minimum reflection loss value of -51.57dB and a widest effective absorption bandwidth of 5.70GHz at the thickness of only 1.7mm with merely 8wt% filler. This work provides a scalable strategy for the construction of multicomponent PBA-derived composites for lightweight and high-performance microwave absorption.

The surface of Chinese-manufactured T800 carbon fiber (CF) underwent air ICP plasma treatment to enhance its interfacial bonding with polyimide resin at high temperatures. This treatment significantly improved the high-temperature interlaminar shear strength (ILSS) of the CF/PI composite. Optimal treatment, achieved at a power of 200W, resulted in an ILSS retention rate of 67.34% at 300 degrees C and maintained ILSS at 66.46MPa at 350 degrees C. At this power level, the CF surface developed protrusions, increasing its roughness to 155.70 nm and its oxygen content to 18.32%. Additionally, the ratio of polar to nonpolar groups increased to 0.98, and the ID/IG value rose to 2.781. These changes were important reasons for enhancing the high-temperature ILSS of CF/PI composite. [GRAPHICS]