In Situ Synthesis of C-N@NiFe2O4@MXene/Ni Nanocomposites for Efficient Electromagnetic Wave Absorption at an Ultralow Thickness Level

Abstract

Recently, the development of composite materials composed of magnetic materials and MXene has attracted significant attention. However, the thickness and microwave absorption performance of the composite is still barely satisfactory. In this work, the C-N@NiFe2O4@MXene/Ni nanocomposites were successfully synthesized in situ by hydrothermal and calcination methods. Benefiting from the introduction of the carbon-nitrogen(C-N) network structure, the overall dielectric properties are improved effectively, consequently reducing the thickness of the composite while maintaining excellent absorption performance. As a result, the minimum reflection loss of C-N@NiFe2O4@MXene/Ni can reach −50.51 dB at 17.3 GHz at an ultralow thickness of 1.5 mm, with an effective absorption bandwidth of 4.95 GHz (13.02–18 GHz). This research provides a novel strategy for materials to maintain good absorption performance at an ultralow thickness level.

MXene Nanosheet/Polypyrrole Composite Felt with a Continuous Impedance-Gradient Structure for Electromagnetic Wave Absorption

“…The straight line and the semicircle in Cole–Cole’s curve represent the conduction loss and the polarization loss, respectively . Ordinary polyester felt is neither conductive nor magnetic and is a transparent material that has no protective effect against EM waves.…”

“…The straight line and the semicircle in Cole−Cole's curve represent the conduction loss and the polarization loss, respectively. 31 Ordinary polyester felt is neither conductive nor magnetic and is a transparent material that has no protective effect against EM waves. After being coated with MXene and PPy, MXene/PPy as a conductive composite absorbent coated polyester felt forms a good conductive network, which provides a wide range of transport channels for carrier migration, thus improving the conductive loss capacity.…”

The In Situ Preparation of Ni–Zn Ferrite Intercalated Expanded Graphite via Thermal Treatment for Improved Radar Attenuation Property

“…The attenuation constant (α) is often used to reflect the dissipative capacity of materials to the incident electromagnetic wave. According to electromagnetic wave transmission theory, the attenuation constant can be expressed as Equation (14) [ 51 , 52 , 53 ]. where and are the real and imaginary parts of the complex permittivity of materials and and are the real and imaginary parts of the complex permeability of materials.…”

Well-matched PANI@FePO4@FeSi hybrid composite with excellent microwave absorption property

“…Figures 6(a)-(c) display the complex permittivity of the PANI@FePO 4 @FeSi samples with different reaction time. The dielectric constants of all the samples fluctuate considerably over the entire frequency range, which is attributed to the dielectric polarization relaxation [6,26]. Two relaxation peaks around 10 GHz and 17.5 GHz are spotted in e ascribe to the dipole polarization and interfacial polarization [27].…”

“…Fe, Co or Ni magnetic metal-based composites play critical role as microwave absorbing materials for their large permeability, high saturation magnetization and curie temperature [1][2][3][4]. However, the skin effect weakens impedance matching and restrains further improving microwave absorption ability [5][6][7][8]. To address these issues, coating of non-magnetic dielectric material can effectively isolate the metal particles, suppress the eddy current effect.…”