JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
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2024
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IF 2.5
Liang Yan,Yujing Zhang,Yilin Zhang,Rui Liu,Chuyang Liu,Fan Wu,Xuefei Miao,Er Liu,Xiaoling Peng,Jing Li,Shan Tao,Feng Xu
LaFeO 3 perovskite has possessed great potential in the field of microwave absorption considering its outstanding dielectric and magnetic properties. In this work, Bi-doped LaFeO 3 powders (BLFO) were prepared by a simple solid state reaction method. The results have demonstrated that the crystalline of LaFeO 3 and the lattice oxygen are increased with the additionally introduced Bi. As a result, the samples could exhibit the strongest microwave absorption with the minimum reflection loss (RL min ) of −39.48 dB and the effective absorption band (EAB) of 3.63 GHz (10.28–13.91 GHz) at a filling ratio of 60 wt%. The excellent microwave absorption properties are ascribed to the enhanced conductive loss, polarization relaxation and the co-existed magnetic loss. Moreover, the optimum sample exhibits the radar cross-section values below −10 dBm 2 across a wide angular range of −90° to 90° with a thickness of 2.5 mm. Therefore, this work opens up a feasible and effective way for modulating the electromagnetic properties of perovskite materials as potential microwave absorbents.
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
RSC Advances
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2017
·Vol. 7
·期 40
·24698-24708
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IF 3.108
Youbing Li,Xiaobing Zhou,Jing Wang,Qihuang Deng,Mian Li,Shiyu Du,Young-Hwan Han,Jaehyung Lee,Qing Huang
A novel family of Ti3C2Tx/ferrite composites with high reflection loss was developed using a facile in situ co-precipitation method. The as-synthesized Ti3C2Tx/ferrite composite with a 5 wt% Ti3C2Tx MXenes loading exhibited high reflection loss (−42.5 dB) at 13.5 GHz. The effective absorption bandwidth of the 5 wt% Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composite reached ∼3 GHz (12–15 GHz) in the K-band. The incorporation of Ti3C2Tx MXenes improved the electromagnetic impedance of the Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composite resulting from the enhanced electrical conductivity. The potential electromagnetic wave absorption mechanisms were revealed, which may contain magnetic loss, dielectric loss, conductivity loss, multiple reflections, and scattering. The technique is facile, fast, scalable, and favorable for the commercialization of this composite. This study provides a potential way to develop EM wave absorbing materials for a large family of MXenes/ferrite composites.
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
Materials Today Chemistry
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2021
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IF 8.301
H. Zhang,J. Xu,S. Wang,Q. Liu,X. Kong
Iron-based nanostructured materials are desirable for various applications owing to their high magnetization. Herein, we presented a facile fabrication of free-standing γ-Fe 2 O 3 nanosheets by a molten salt method for microwave absorption. Furthermore, Al component was incorporated to serve as the template for hole production. The designed holey γ-Fe 2 O 3 nanosheets were effective to maximize the usage of nanomaterials, thereby providing larger surface area, richer defects, and more polarization centers. Both experimental measurements and electric field simulation showed an enhanced capability for microwave absorption using holey γ-Fe 2 O 3 when compared with its intact counterpart. Oxygen vacancy was generated during the hole evolution, which significantly improved the electrical conductivity and thus promoted the conductive loss mechanism. In addition, the holey configuration may extend the transmission path of microwave and confer it with multiple reflection and scattering within the absorbent matrix. Meantime, the polarization loss was strengthened owing to Al modulation associated with the induced defect sites. With the improvement in conductive loss, polarization, impedance matching, and attenuation constant, the as-synthesized holey γ-Fe 2 O 3 exhibited promising microwave absorbability, with a maximum reflection loss of 52.4 dB and an effective bandwidth of 5.12 GHz at a thickness of 2.2 mm, overperforming most pure Fe-based materials.
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
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IF 4.9
Chunmiao Liu,Yanchun Tong,Chang Liu,Meng Xu,Haibin Sun,Shigang Wu,Yujun Zhao,Jiao Li,Xue Guo,Yurun Feng
Faced with severe electromagnetic wave (EMW) pollution, the development of high-performance EMW absorbers remains a formidable challenge. In this study, SiBCN/Ni fibers containing uniformly dispersed Ni 2 Si nanoparticles were synthesized by electrospinning method with polymer-derived ceramics method, and their electromagnetic properties were evaluated. The low permeability threshold of the fibers ensures sufficient conduction loss effect. The in situ grown Ni 2 Si nanoparticles provide a magnetically coupled network, which is more conducive to obtaining excellent impedance matching. Furthermore, the presence of β-SiC, SiO 2 , and Si 2 N 2 O generates numerous heterogeneous interfaces (e.g., C-SiC and C-Ni 2 Si), leading to enhanced interfacial polarization through the accumulation of charges. As a result, the prepared SiBCN/Ni fibers exhibit impressive EMW absorption properties . At a Ni content of 1 wt%, the effective absorption band (EAB) is 4.32 GHz (13.68–18 GHz). At a Ni content of 1.5 wt%, the minimum reflection loss (RL min ) is −52.98 dB, and the sample has excellent radar scattering capabilities, which is verified by CST Microwave Studio simulations. Therefore, SiBCN/Ni fibers are promising as excellent EMW absorbing materials in practical applications.
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
Nanoscale
·
2024
·
IF 5.8
Hexing Liu,Jian Wang,Yunfan Wang,Zhonghui Shen,Xin Zhang,Bao-Wen Li
Polyvinylidene fluoride (PVDF) film, with high energy density and excellent mechanical properties, has drawn attention as an energy storage device. However, conduction loss in PVDF under high electric fields hinders improvement in efficiency due to electrode-limited and bulk-limited conduction. Well-aligned multilayer interfaces of two-dimensional (2D) nanocoatings can block charge injection, reducing electrode-limited conduction loss in dielectric polymers. Thus, rational selection of 2D fillers is crucial for designing high-energy-density dielectric materials. This study explores 2D oxide nanosheets with varying dielectric constants and bandgaps, such as Ti0.87O2, Ca2Nb3O10, and montmorillonite (MMT). Ca2Nb3O10 nanosheets, with a higher dielectric constant and similar bandgap to Ti0.87O2, created a higher Schottky barrier (0.6 eV), resulting in a discharge energy density (Ud) of 26.4 J cm−3 at 720 MV m−1 in PVDF-Ca2Nb3O10 film. The PVDF-MMT film, coated with MMT nanosheets featuring a lower dielectric constant yet a higher bandgap, achieves a similar Ud of 26.8 J cm−3 at 720 MV m−1, with efficiencies (η) above 80% for both films. The results indicate that the bandgap and dielectric constant of 2D nanosheets play a crucial role in determining PVDF composites’ energy storage density and efficiency, necessitating a balance between these parameters. Furthermore, ultraviolet (UV) irradiation was introduced to induce trap centers and inhibit charge conduction and energy loss in PVDF-based composites under high electric fields. Consequently, the UV-treated PVDF-MMT composite film achieves a Ud of 29.1 J cm−3 and an η of 78.3% at 750 MV m−1. This work offers an effective strategy for developing high-energy density, high-efficiency PVDF-based polymer materials.
研究领域:
材料科学
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能源工程
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DOI
PubMed
高影响因子
Materials Horizons
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2024
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IF 12.2
Xu Fan,Zhicheng Li,Yu Zhang,Peng Wang,Jinjun Liu,Jinhong Yu,Jiwei Zhai,Weiping Li,Zhongbin Pan
Dielectric capacitors are pivotal elements in advanced pulsed power devices and high-voltage, high-capacity power electronic converters, crucial for efficient energy storage. However, a major challenge remains the significant reduction in energy density and charge–discharged efficiency of dielectric polymers under high temperatures, primarily due to heightened electrical conduction losses. This study introduces a universal approach of heterojunction interface engineering in polyethersulfone (PESU) composites, aimed at improving capacitive performance across a broad temperature range. The introduction of one-dimensional heterojunction BaTiO3@Al2O3 nanofibers with large aspect ratios could enhance both the dielectric constant (εr) and breakdown strength (Eb). Specifically, the creation of hierarchical interfaces increases the trap density and energy levels for mobile charges, effectively reducing conduction losses and improving Eb under high-temperature conditions. Consequently, the PESU-3 vol% BaTiO3@Al2O3 nanocomposite achieves an excellent energy density of 7.3 J cm−3 with over 90% retention at 150 °C and 550 MV m−1. Finite element simulations further confirm that the heterojunction structure of BaTiO3@Al2O3 nanofibers effectively inhibits the growth of breakdown paths. This work demonstrates that hierarchical interface engineering offers a powerful strategy to enhance capacitive performance in dielectric polymer composites under harsh conditions.
研究领域:
材料科学
·
电气工程
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）