Showing papers on "Dielectric loss published in 2022"
TL;DR: In this article , comprehensive views toward dielectric loss mechanisms including interfacial polarization, dipolar polarization, conductive loss, and defect-induced polarization are provided, and in-depth losses and mechanisms regulation strategies instead of regular components compositing are summarized to provide inspiring thoughts toward simple and effective EM wave attenuation behavior modulation.
Abstract: Electromagnetic (EM) wave absorbing materials play an increasingly important role in modern society for their multi‐functional in military stealth and incoming 5G smart era. Dielectric loss EM wave absorbers and underlying loss mechanism investigation are of great significance to unveil EM wave attenuation behaviors of materials and guide novel dielectric loss materials design. However, current researches focus more on materials synthesis rather than in‐depth mechanism study. Herein, comprehensive views toward dielectric loss mechanisms including interfacial polarization, dipolar polarization, conductive loss, and defect‐induced polarization are provided. Particularly, some misunderstandings and ambiguous concepts for each mechanism are highlighted. Besides, in‐depth dielectric loss study and novel dielectric loss mechanisms are emphasized. Moreover, new dielectric loss mechanism regulation strategies instead of regular components compositing are summarized to provide inspiring thoughts toward simple and effective EM wave attenuation behavior modulation.
246 citations
TL;DR: In this paper , a laminate-stacked sphere-shaped trimetallic CoNiMnO@C composites were designed to investigate the polarization loss mechanism, which facilitates the improvement of electromagnetic loss capacity.
Abstract: Polymeric metal‐organic framework (MOF)‐derived composites are promising functional materials because of their exceptional chemical homogeneity, designable components, and adjustable pore size. The modulation of oxygen and Mn vacancies via the introduction of heteroatoms and changes in the annealing temperature in MOFs‐derived composites can be a possible solution to investigate the polarization loss mechanism, which facilitates the improvement of electromagnetic loss capacity. Herein, the design of laminate‐stacked sphere‐shaped trimetallic CoNiMn‐MOFs is presented. The derived CoNi/MnO@C composites retain the original topography of the MOFs. The concentration of oxygen vacancies increases with the incorporation of heteroatoms, but decreases with annealing temperature, which prevails in the polarization loss mechanism rather than the contribution of Mn2+ vacancies and heterogeneous interfaces. Therefore, the minimum reflection loss of the CoNi/MnO@C sample demonstrates −55.2 dB at 2.6 mm and the broad effective absorption bandwidth reaches 8.0 GHz at 2.1 mm. This work is expected to provide meaningful insights into the significant effect of ion vacancy modulation on the EM wave‐absorbing performance of Mn‐based MOFs‐derived composites.
149 citations
TL;DR: In this paper, a magnetic ferrite CuFe2O4/MoS2 composite was constructed to achieve a wide effective absorption bandwidth (EAB) of 8.16 GHz (9.84 GHz −18 GHz) at 2.3 mm.
127 citations
TL;DR: In this paper , a magnetic ferrite CuFe2O4/MoS2 composite was constructed to achieve a wide effective absorption bandwidth (EAB) of 8.16 GHz (9.84 GHz −18 GHz) at 2.3 mm, when the optimum reflection loss is −40.33 dB.
113 citations
TL;DR: In this paper, the effect of Fe doping on the dielectric and magnetic properties of LCFOs and the strong hybridization of Co/Fe-3d with O-2p was successfully demonstrated.
109 citations
TL;DR: In this paper , 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.
Abstract: 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 (RLmin) 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.
89 citations
88 citations
TL;DR: In this article, the effect of N-doped carbon skeletons on the absorption ability of carbon-based absorbers has been investigated, and the authors provided a valuable approach for fabricating high-efficiency microwave absorption materials by combining the control of morphology and Ndoped effect on the absorbers.
88 citations
TL;DR: In this paper, NiFe2O4/polypyrrole nanocomposites are prepared by a simple surface-initiated polymerization method and demonstrate negative permittivity in the low frequency regions.
86 citations
01 May 2022
TL;DR: In this article , NiFe2O4/polypyrrole nanocomposites are prepared by a simple surface-initiated polymerization method and demonstrate negative permittivity in the low frequency regions.
Abstract: NiFe2O4/polypyrrole (NiFe2O4/PPy) nanocomposites are prepared by a simple surface-initiated polymerization method and demonstrate negative permittivity in the low frequency regions. These nanocomposites also exhibit significantly enhanced electromagnetic wave (EMW) absorption property in the high frequency regions. Compared with pure PPy, the enhanced negative permittivity is observed in the NiFe2O4/PPy nanocomposites with a NiFe2O4 loading of 5.0, 10.0, 20.0 and 40.0 wt%, indicating the formation of metal-like electrical conducting network in NiFe2O4/PPy nanocomposites. Moreover, the negative permittivity could be tuned by changing the NiFe2O4 loading. The minimum reflection loss (RL) of -40.8 dB is observed in the 40.0 wt% NiFe2O4/PPy composites with a thickness of only 1.9 mm. The effective absorption bandwidth below -10.0 and -20.0 dB reaches 6.08 and 2.08 GHz, respectively. The enhanced EMW absorption performance benefits from the improved independence matching, EMW attenuation capacity, and synergistic effects of conduction loss, dielectric loss (interfacial and dipole polarizations) and magnetic loss (exchange and natural resonances). This research work provides a guidance for the fabrication of nanocomposites with an excellent EMW absorption.
83 citations
01 Jun 2022
TL;DR: In this article , a series of loosely packed accordion-like 3D NiCo/CeO2/Ti3C2Tx with tunable and high-efficient EMW absorption were fabricated by introducing self-assembled NiCo alloys on the surface of Ti3C 2Tx and subsequent anchoring of CeO2.
Abstract: The single dielectric/magnetic loss mechanism and invalid polarization loss are the crucial issues which limit the exploitation of multi-component electromagnetic wave (EMW) absorption materials, especially Ti3C2Tx MXene based absorption materials. In this work, a series of loosely packed accordion-like 3D NiCo/CeO2/Ti3C2Tx with tunable and high-efficient EMW absorption were fabricated by introducing self-assembled NiCo alloys on the surface of Ti3C2Tx and subsequent anchoring of CeO2. On the one hand, the magnetic NiCo particles and highly conductive Ti3C2Tx achieved the dielectric-magnetic dual-loss. On the other hand, the triple interfacial polarization among NiCo/CeO2/Ti3C2Tx further enhanced the relaxation loss. In addition, the effects of cerium ions on tuning the compositional structure, electromagnetic parameters and impedance behavior of the composites are explored. The NiCo/CeO2/Ti3C2Tx-0.1 performed a wide absorption bandwidth of 6.32 GHz at 1.9 mm, as well as, the minimum reflection loss value of -42.48 dB at 2.0 mm. This work putted forward a new synergistic regulation strategy of dielectric-magnetic dual-loss and triple heterointerface polarization via magnetic MXene for high-performance EMW absorption, which may shed new light on the fabrication of multiple-component synergistic loss absorption materials.
TL;DR: In this article , the effect of N-doped carbon skeletons on the absorption ability of carbon-based absorbers has been investigated, and the authors provided a valuable approach for fabricating high-efficiency microwave absorption materials by combining the control of morphology and Ndoped effect on the absorbers.
TL;DR: In this article, MgFe2O4/MgO/C fibers were successfully prepared via electrospinning technology and carbonization, and their surfaces were coated by MoS2 via hydrothermal method.
TL;DR: In this article , MgFe2O4/MgO/C fibers were successfully prepared via electrospinning technology and carbonization, and their surfaces were coated by MoS2 via hydrothermal method.
TL;DR: In this article, a high-density 2D Ni2P nanosheets were grown vertically and cross-linked on the surface of 1D silk-derived carbon fiber.
TL;DR: In this article , 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.
Abstract: 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 (RLmin) 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.
TL;DR: In this paper, a multi-layered hexagonal-like carbon nanotubes (MWCNTs/MnF2/CoO composite is prepared via one-step hydrothermal and annealing process.
01 Feb 2022
TL;DR: In this article , a high-density 2D Ni2P nanosheets were grown vertically and cross-linked on the surface of 1D silk-derived carbon fiber.
Abstract: Considering a series of electromagnetic pollution problems brought by the development of electronic communication technology, more attention has been paid to the research of electromagnetic wave (EMW) absorbing materials with unique composition and structure. Herein, under the inspiration of mixed-dimensional hierarchical structure, 2D Ni2P nanosheets anchored on 1D silk-derived carbon fiber is successfully fabricated as a gratifying resistor-dielectric type absorber. By a controllable pyrolyzation strategy and disproportionated reaction, high-density 2D Ni2P nanosheets were grown vertically and cross-linked on the surface of 1D silk-derived carbon fiber. The sample exhibited superior EMW absorption performance with maximum reflection loss value of – 56.9 dB at the thickness of 2.32 mm and the effective absorption bandwidth can reach to 7.2 GHz at the thickness of 1.93 mm. In addition, the pure Ni2P shows remarkable dielectric characteristic and EMW absorption ability as well. The integration of dual-conductive loss, enhanced polarization relaxation loss and the multiple scattering in the composites was proved to contribute to the good EMW absorption performance. Therefore, this work confirms the great potentials of Ni2P as a high-efficient EMW absorbing materials and light a new way in construction of multidimensional absorber.
TL;DR: In this article , a series of multi-element core-shell magnetic nano-particle composite layered graphene absorbing materials CoFe 2 O 4 @C/rGO (CCr) were prepared by adjusting carbon shell thickness.
TL;DR: In this article, a series of multi-element core-shell magnetic nano-particle composite layered graphene absorbing materials CoFe2O4@C/rGO (CCr) were prepared by adjusting carbon shell thickness.
TL;DR: In this article, PPy planar microhelixes anchored with Fe3O4 nanoparticles were constructed via a simple chemical oxypolymerization coupled with a solvothermal method.
TL;DR: In this paper , a controllable seeding of nitrogen-doped carbon nanotubes (NCNTs) on the surface of Co/C foams through in-situ growth is demonstrated.
TL;DR: In this paper , a 2D/2D Ni/Mo 2 TiC 2 T x was constructed by loading spherical and flower-like Ni on delaminated Mo 2TiC 2T x MXene using the solvothermal route, indicating outstanding microwave absorption (50.36 dB at 1.4 mm only).
TL;DR: In this paper, a core-shell structural carbon microsphere/magnetic metal composites were fabricated through the combination of an electrostatic assembly approach and subsequent in-situ reduction reaction.
TL;DR: In this paper , 3D flower-like hollow [email protected] microspheres were fabricated by a solvothermal process followed by in-situ polymerization, indicating the minimum reflection loss (RLmin) of -71.1 dB and effective absorption bandwidth (EAB) covering 81% of test frequency range.
TL;DR: In this article , a core-shell structural carbon microsphere/magnetic metal composites were fabricated through the combination of an electrostatic assembly approach and subsequent in-situ reduction reaction.
TL;DR: In this paper , a hierarchical multi-shell [email protected]@TiO2@MoS2 (FCTM) microsphere is fabricated via an in-situ reduction process.
TL;DR: In this article, a hollow ZnO/ZnS/CuS composite was constructed using a hard template and based on the diverse binding ability of Cu and Zn ions to S ions, the compositions, interfaces, and defects of the sample were simultaneously regulated.
TL;DR: In this paper , a hollow ZnO/ZnS/CuS composite was constructed using a hard template and based on the diverse binding ability of Cu and Zn ions to S ions, the compositions, interfaces, and defects of the sample were simultaneously regulated.
TL;DR: In this article, a hierarchical multi-shell Fe@C@TiO2@MoS2 (FCTM) microsphere is fabricated via an in-situ reduction process.