CERAMICS INTERNATIONAL
·
2024
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IF 5.1
Yue Liu,Xiuyun Ren,Xinfeng Zhou,Di Lan,Zhenguo Gao,Zirui Jia,Guanglei Wu
Vacancy engineering presents an appealing method for modifying the electronic structure of spinel architectures. However, based on well-defined vacancy concentrations, how to design anionic vacancies to modulate electromagnetic parameters as well as electromagnetic wave absorption (EMA) properties is less studied. Here, NiCo 2 Se 4 spinel structures were prepared using different selenization methods, and the Se vacancy defect concentration was controlled by changing the annealing temperature, thus regulating the EMA properties. Among them, the design of the hollow structure effectively enhanced the EMA performance. Moreover, the increase of Se vacancy concentration increases the conductivity loss while regulating the electronic structure, and also acts as an unsaturated site to induce the formation of dipoles to optimize the polarization loss. The effective absorption bandwidth (EAB) of NiCo 2 Se 4 -130 reaches 8.48 GHz at 2.4 mm at the highest Se vacancy concentration. This work establishes a direct relationship between vacancy concentration and the electromagnetic wave dissipation capability, offering valuable insights for the development of advanced EMA materials.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Composites and Hybrid Materials
·
2024
·Vol. 7
·期 2
·1-16
·
IF 23.2
Yuan Liying,Zhao Wenxin,Miao Yukun,Wang Chang,Cui Anguo,Tian Zhongning,Wang Ting,Meng Alan,Zhang Meng,Li Zhenjiang
The inadequate impedance matching and weak attenuation capability for incident electromagnetic waves exhibited by carbon fibers (CF) are critical factors limiting their application served as absorbing materials. Constructing a nanocomposite system that simultaneously exhibits both dielectric loss and magnetic loss characteristics is a feasible strategy to overcome these limitations. In the present study, a core-shell CF@PPy@CoFe 2 O 4 nanocomposite is fabricated through electrodeposition and subsequent hydrothermal methods to enhance the attenuation capacity and impedance matching of bare CF. Under the synergistic effects of diverse components and a peculiar network structure, the nanocomposite demonstrates optimized conductive loss and polarization loss, which results in a remarkable electromagnetic wave absorption performance with a minimum reflection loss (RL min ) of -55.33 dB and an effective absorption bandwidth (EAB) of 6.48 GHz (12 ~ 18 GHz) at optimal thicknesses of 2.11 and 2.42 mm, respectively, suggesting its promising application as a candidate absorber. More importantly, the exploration concerning the absorption mechanism provides significant insights into the attenuation modes of the dielectric-magnetic loss hetero-junction, which is beneficial for developing similar absorbing materials. Graphical abstract
CF@PPyCoFe 2 O 4 nanocomposite displays an efficient electromagnetic wave absorption capacity by virtue of its excellent conductive loss and polarization loss.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2024
·
IF 10.5
Kaiming Wang,Xin Gong,Xinyu Ye,Jinxu Li,Yang Yang,Huacheng Zhu,Yuesheng Wang,Liping Yan,Yanping Zhou
Biomass char is very promising in developing microwave absorbing materials with low minimum reflection loss (RL min ) and ultrawide effective absorption bandwidth (EAB) owing to its low cost and natural availability of various pores, but however is facing a dilemma between the conduction loss and interface polarization loss where new heating technology is highly desirable. In this work, a microwave confined plasma/microwave hybrid heating technology is developed based on the unique interaction between porous carbon and microwave for simultaneous enhancement of conduction loss and interface polarization loss of cellulose char. Compared to the conventional heating product at the same temperature, the as-prepared microwave char showed almost doubled conductivity which is beneficial for conduction loss, higher content of C –O bond that has longer bond length and dielectric susceptibility than C O bond, and more condensed carbon nanoparticles embedded in the carbon matrix which is responsible for increasing the heterointerface polarization loss. As such the tangent loss of MW900-40 % ranges from 0.69 to 0.97 while that of CH900-40 % only ranges from 0.34 to 0.64 in the frequency range of 2.0–18.0 GHz. Further, based on multilayer impedance gradient principle, a double-layer absorber is constructed with products of different MW900 loading, yielding a RL min of −59.0 dB at 15.9 GHz with an EAB of 10.0 GHz at 4.0 mm, whose working mechanism is comprehensively studied by simulations in terms of impedance matching and microwave dissipation distribution.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Linyun Zhang,Yijing Sun,Shanxin Li,Xuzhou Jiang,Hongying Yu
M−Mo−N (M = Co, Ni) bimetallic nitrides, known for their distinctive mechanical, magnetic and electrical properties, hold significant potential as microwave absorption (MA) materials. However, it remains challenge to obtain high-performance microwave absorbers from these bimetallic nitrides. In this work, the rod-like MoO 2 /Co 2 Mo 3 N/Co 3 Mo 3 N/Ni 3 Mo 3 N (MoCoNi) composites consisting of connected nanoparticles are fabricated in situ. The plentiful interfaces between the connected nanoparticles and between the different components effectively enhance the interfacial polarization, the rod-like structure benefits to conduction loss, and crystal defects facilitate strong dipole polarization. Therefore, MoCoNi composites achieve outstanding absorption properties with the reflection loss of −55.69 dB at 8.08 GHz and the effective absorption bandwidth of 6.48 GHz (11.36–17.84 GHz) at 2.4 mm. The actual MA performance of MoCoNi composites is verified through radar cross section simulation. This study proposes a novel approach for the utilizing of M−Mo−N (M = Co, Ni) bimetallic nitrides in microwave absorptions.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 30
·7621-7628
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IF 5.256
Xinliang Li,Xiaowei Yin,Meikang Han,Changqing Song,Xinnan Sun,Hailong Xu,Laifei Cheng,Litong Zhang
Herein, Ti2CTx MXene and its derivatives with various heterogeneous structures were constructed via etching and a facile oxidation treatment. The effect of different oxidation conditions on their structural evolution and phase composition was studied in detail. Compared with that of pristine Ti2CTx MXene, the improvement in the electromagnetic wave absorption capability of the as-prepared Ti2CTx/TiO2 and C/TiO2 nanocomposites was attributed to their enhanced polarization loss and stronger conductivity loss. The enhanced polarization loss is caused by the generated heterogeneous interfaces and higher specific surface area, and the stronger conductivity loss is due to the completely exfoliated carbon layers. Additionally, the remaining multilayered structure after exfoliation of the carbon layers favors energy dissipation. The C/TiO2 nanocomposites attain a minimum reflection coefficient of −50.3 dB at 7.1 and 14.2 GHz, and an effective absorption bandwidth of 4.7 GHz (covering the whole X-band) with a matching thickness of 2.1 mm; this indicates their excellent electromagnetic wave absorption properties. We believe that these nanocomposites with a heterogeneous structure also hold great promise for application in the fields of photocatalysis, lithium batteries, water purification, etc.
研究领域:
材料科学
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电磁学
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
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2025
·
IF 6.3
Qingkun Xu,Xiurong Zhu,Jiawei Zhu,Peng Liao,Yi Yu,Zuzou Xiong,Xianke Zhang,Jvjun Yuan,Xiaoqing Liu
To incorporate magnetic metals into carbon materials is a proven method to achieve highly efficient electromagnetic wave absorption (EMA) capabilities. In this study, cobalt (Co)-iron (Fe) alloys doped phenolic-based carbon aerogels (CoFe-CAs) with an impressive core-shell structure were prepared by using 1,2-epoxypropane as catalyst via a simplified sol-gel method. The effect of annealing temperature on the EMA properties of CoFe-CAs was explored and the X-ray diffractometer, Raman spectrometer, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, selected area electron diffraction, N 2 isothermal adsorption-desorption curves and vector network analyzer were used to acquire their physical and chemical properties. The results show that the CoFe-CAs (S-1050) with an impressive core-shell structure possess outstanding EMA performance, the minimum reflection-loss value reaches -58.46 dB (matching thickness: 2.1 mm, frequency: 12.9 GHz) while the maximum effective-absorption-bandwidth displays 5.7 GHz (frequency range: 12.13–17.83 GHz, matching thickness: 1.84 mm), the minimum radar-cross-section value displays -40.02 dB m 2 in a range of 0° to 360°. The excellent EMA performance of CoFe-CAs can be mainly attributed to the high conduction loss derived from their graphitized carbon, the polarization loss resulted from their impressive core-shell structure, high specific surface area and rich pore structure, and the impedance matching characteristics optimized by the good synergy of dielectric loss and magnetic loss. This study provides a new catalyst and a simplified method for the preparation of magnetic metal doped phenolic-based CAs with excellent EMA properties.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Jiahao Wang,Lei Zhang,Junfeng Yan,Jiangni Yun,Wu Zhao,Kun Dai,Huan Wang,Yushan Sun
MXene, a highly regarded material, has garnered significant attention within the electromagnetic wave (EMW) absorption field. However, the practical application of MXene is limited in harsh environments. Herein, a magic technique strategy of intercalation growth nucleation engineering is employed to prepare multifunctional MXene-based EMW absorption materials. By regularly introducing different metal ions between the layers of MXene, an ultrathin absorber can be achieved by annealing after reacting in specific positions. The synthesized MCFC-69-8 shows hydrophobicity properties and exhibits a large charge-transfer resistance of 18112 Ω cm 2 with a low corrosion rate and corrosion rate, indicating a good anti-corrosion property. Through applying a series of mathematical methods, MCFC-69-8 shows 25% relaxation polarization loss and 75% conduction loss, and its relaxation time is linked with the specific type of relaxation polarization loss, resulting in an effective absorption bandwidth (EAB) of 4.9 GHz with an ultra-thin optimal matching thickness of 1.48 mm. Finally, an absorber is built using CST to attain an ultrabroad EAB covering 2–18 GHz. This engineering not only simplifies the intercalation process but also achieves a high-performance and anti-corrosion EMW absorber, providing a valuable perception for realizing thinner MXene-based EMW absorbers in the future.
研究领域:
材料科学
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电磁学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Jie Liu,Chunmiao Liu,Yanchun Tong,Haibin Sun,Hui Peng,Mingwei Zhang,Shigang Wu,Hongying Zhang,Hongyu Gong,Zhiqin Zheng,Xue Guo,Yurun Feng
The SiCN/Fe/Ni ceramics codoped with iron acetylacetonate (FA) and nickle acetylacetonate (NA) was synthesized by polymer-derived ceramics (PDCs) method in this study. The microstructure, phase composition and electromagnetic wave (EMW) absorption properties of the samples were analyzed. The polarization loss and conduction loss of materials were analyzed by the direct current (DC) multimeter and the contribution rate of polarization loss was more than 94% in the whole frequency band. The results showed that C, SiC, Fe 2 Si, Ni 3 Si, γ- (Fe, Ni) and CNTs were formed after pyrolysis which provided lots of heterogeneous interface and enhanced the interfacial polarization. Meanwhile, Ni could enter the lattice of Fe and formed a unique electronic configuration, which reinforced the conductivity and stability of Fe. In addition, the in-situ generated Fe 2 Si and Ni 3 Si provided magnetic loss and conduction loss. The RL min value of SiCN/Fe/Ni-3 ceramic was −52.06 dB at 1.54 mm and the effective absorption band (EAB, RL ≤ −10 dB) reached 4.21 GHz (13.79–18 GHz, 1.43 mm).
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2024
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IF 5.8
Yan Cheng,Kai Zhou,Yongzhen Ma,Huanqin Zhao,Haibo Yang
Developing the synergistic magnetic-dielectric composites with multiple loss mechanism as excellent microwave absorber is the goal pursued by researchers, but the effective regulation of specific mechanism still remains a challenge. In this work, we fabricated the customized composites of mesoporous carbon hollow sphere (MCHS)@Co@carbon nanotubes (CNTs) for high-performance microwave absorption (MA). First, MCHS with hierarchical porous structure was selected as light dielectric substrate. Then, metal Co nanoparticles were introduced into the pores of MCHS to provide magnetic loss and as catalyst. Last, the CNTs are in-situ grafted on MCHS to serve as electrons transportation channels to reinforce conductive loss. The obtained magnetic-dielectric composites integrated multiple loss mechanism present excellent MA performance with strong absorption intensity of –37.3 dB and wide effective absorption bandwidth of 8.0 GHz under low filling ratio of 20%. Moreover, the conductive loss can be tuned through regulating the length of CNTs. It is confirmed that the appropriate length of CNTs can endow the composites with feasible microwave attenuation ability and impedance matching feature. This work provides a new way to control loss mechanism from microstructure design to optimize MA capability.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2025
·
IF 14.3
Pengcheng Shu,Juhua Luo,Xinzhi Zhou,Yun Cui,Ziyang Dai,Yuhan Wu,Xing Liu,Xiangcheng Li
Graphitic carbon nitride (g-C 3 N 4 ) has garnered significant attention due to its remarkable advantages such as lightweight, exceptional chemical stability and defect-rich surface. Nevertheless, its inadequate electrical conductivity and impedance matching hindered the practical implementation in the electromagnetic wave absorption (EMWA) field. To address these challenges, we developed a composites system of carbon spheres/g-C 3 N 4 (CCN) through a supramolecular self-assembly strategy, subsequently integrated with reduced graphene oxide (RGO) via a water bath method. Systematic investigation revealed that the EMWA performance of CCN/RGO composites exhibited a distinct dependence (a trend of first increasing and then decreasing) on RGO content. Especially, when the mass ratio of RGO to CCN was 20%, the CCN/RGO composite brought a minimum reflection loss value of −45.40 dB at 13.44 GHz and a broad effective absorbing bandwidth of 6.32 GHz at 2.19 mm. First-principles calculations based on density functional theory suggested that the constructed heterostructure effectively facilitated electron mobility and charge redistribution, boosting both conductive loss and polarization loss mechanisms. The exceptional absorption performance was ascribed to the synergistic effects of conductive loss, relaxation loss, and suitable impedance matching. As a results, this work provided a rational design strategy for high-performance g-C 3 N 4 -based EMWA materials.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 16
·4068-4074
·
IF 5.256
Xinliang Li,Xiaowei Yin,Meikang Han,Changqing Song,Hailong Xu,Zexin Hou,Litong Zhang,Laifei Cheng
Ti3C2Tx MXenes modified with in situ grown carbon nanotubes (CNTs) are fabricated via a simple catalytic chemical vapor deposition (CVD) process. The as-prepared Ti3C2Tx/CNT nanocomposites show that one-dimensional (1D) carbon nanotubes are uniformly distributed in the interlayers of two-dimensional (2D) Ti3C2Tx MXene flakes. Compared with the pristine Ti3C2Tx MXenes, the hierarchical sandwich microstructure makes a contribution to the excellent electromagnetic wave absorption performance in the frequency range of 2–18 GHz, including higher absorption intensity (the minimum reflection coefficient reaches −52.9 dB, ∼99.999% absorption), broader effective absorption bandwidth (4.46 GHz), lower filler loading (35 wt%) and thinner thickness (only 1.55 mm). In addition, with the adjustment of thickness from 1.55 to 5 mm, the effective absorption bandwidth can reach up to 14.54 GHz (3.46–18 GHz). Different absorption mechanisms mainly based on polarization behaviors and conductivity loss are discussed. This work not only proposes the design of a novel electromagnetic wave absorber, but also provides an effective route for extending further the applications of 2D MXene materials in the field of electromagnetic wave absorption.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Fangyu Gan,Zhenpeng Li,Qingrong Yao,Shasha Jiang,Xiaochang Yu,Jianqiu Deng,Zhao Lu,Lichun Cheng,Maomi Zhao,Huaiying Zhou
Polarization loss and conduction loss are the important attenuation mechanisms in dielectric loss dominant electromagnetic wave (EMW) absorbers, but their synergistic effects in different frequency bands need to be further investigated. In this study, FeNi/ZnO/C/Ni 3 ZnC 0.7 composites (FNZC) were synthesized using a simple and environmentally friendly template-sacrificing method, with water as the only solvent. By varying the elemental addition, the phase and microstructure of the final product can be controlled, which in turn affects the conduction loss and polarization loss, thus altering the EMW absorption performance. The minimum reflection loss (RL) value and EAB of the optimized FNZC composite are –49.23 dB and 5.48 GHz (12.32–18.00 GHz), respectively, covering 99.9 % of the Ku band. Additionally, the RLmin values in the S, C, and X bands are below –17 dB. Based on the component regulation strategy and the analysis of electromagnetic parameters, Cole-Cole curves, and EMW absorption performance, it can be concluded that conduction loss is the primary factor contributing to strong absorption of low-frequency EMW. In contrast, interfacial polarization and defect-induced polarization are the main factors for strong absorption of medium- and high-frequency EMW.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）