CN-122026126-A - Hierarchical heterogeneous interface magnetic-dielectric cooperative wave-absorbing material, preparation method and application

CN122026126ACN 122026126 ACN122026126 ACN 122026126ACN-122026126-A

Abstract

The invention discloses a preparation method of a hierarchical heterogeneous interface magneto-dielectric synergistic wave-absorbing material, which comprises the steps of obtaining a lamellar few-layer graphite dispersion liquid by shearing and stripping expanded graphite through a liquid phase, constructing a nickel-iron layered double hydroxide enrichment micro-area on the surface and the edge of the dispersion liquid in situ, introducing a cobalt source and an iron source precursor, enabling CoFe 2 O 4 nano particles to be preferentially generated on the surface of the enrichment micro-area in situ, and forming a hierarchical heterogeneous interface regulation and control area which is sequentially contacted with local LLG/LDH/CoFe 2 O 4 . The invention solves the problems of poor impedance matching and disordered interface caused by direct contact of magnetic particles and a carbon skeleton in the prior art through a sequential control process, and realizes impedance matching optimization, interface polarization enhancement and magneto-dielectric cooperative loss. When the matching thickness of the obtained composite material is 2.0 mm, the minimum reflection loss reaches-57.2 dB, the effective absorption bandwidth is 5.6 GHz, and the composite material has wide application prospect in the fields of wave-absorbing coating, structural wave-absorbing patches, electromagnetic radiation preventing fabrics and the like.

Inventors

ZHAO ZIYE
WEI PENG
Yue Dianhui
GUO JIA
LIU RONG
DAI JIAMU
ZHANG WEI

Assignees

南通大学

Dates

Publication Date: 20260512
Application Date: 20260325

Claims (8)

1. The preparation method of the hierarchical heterogeneous interface magnetic-dielectric cooperative wave-absorbing material is characterized by comprising the following steps of: Step 1, placing expanded graphite in a water/alcohol mixed solvent containing a nonionic surfactant for liquid phase shearing treatment, and obtaining a lamellar few-layer graphite dispersion liquid after centrifugal separation; Step 2, placing the flaky few-layer graphite dispersion obtained in the step 1 into a reaction system containing a nickel source, an iron source and a precipitant, and reacting under alkaline conditions to ensure that nickel-iron layered double hydroxide nano-sheets preferentially grow on the surface and edge active sites of the flaky few-layer graphite to obtain a composite matrix dispersion with nickel-iron layered double hydroxide enriched micro-areas; Step 3, adding a precursor solution containing a cobalt source and an iron source into the composite matrix dispersion liquid obtained in the step 2, and under the stirring condition, enabling Co and Fe precursors to be preferentially distributed on the surface of the nickel-iron layered double hydroxide enrichment micro-area and/or the peripheral area of the enrichment micro-area, and subjecting the cobalt-iron layered double hydroxide enrichment micro-area to precipitation control or hydrothermal treatment to enable CoFe 2 O 4 nano particles to be generated in situ or be preferentially deposited on the surface of the nickel-iron layered double hydroxide enrichment micro-area; and 4, separating, washing and drying the composite system obtained in the step 3 to obtain the magneto-dielectric synergistic wave-absorbing composite material.
2. The method according to claim 1, wherein in the step 1, the thickness of the flake-like few-layer graphite is less than 5 nm and the number of layers is less than 10, and the intensity ratio I_D/I_G of the D peak to the G peak in the Raman spectrum of the flake-like few-layer graphite is less than 0.5.
3. The method according to claim 1, wherein in step 2, the nickel-iron layered double hydroxide enrichment microdomains are composed of nanosheets having a lateral dimension of 20-200 nm and a thickness of 2-10 nm, and the nanosheets are attached to the surface of the lamellar less graphite in a vertical, inclined, clustered, flower-like, island-like or a combination thereof form.
4. The method according to claim 1, wherein the mass ratio of the flake few-layer graphite, the nickel-iron layered double hydroxide and the CoFe 2 O 4 is (1-2): 1.5-2.5): 4-6.
5. The method of claim 4, wherein in step 3, the particle size of the CoFe 2 O 4 nano-particles is 20-50 nm, and the particles are mainly distributed on the surface of the nickel-iron layered double hydroxide enrichment micro-region and/or the peripheral area of the enrichment micro-region, and allow partial direct contact with the flake-like few-layer graphite, and mainly contact the CoFe 2 O 4 nano-particles with the nickel-iron layered double hydroxide enrichment micro-region.
6. The method of claim 1, wherein in step 2 the Zeta potential of the composite matrix dispersion of nickel iron layered double hydroxide enriched microdomains is less than-20 mV.
7. The hierarchical hetero-interface magneto-dielectric synergistic wave-absorbing material prepared by the preparation method of any one of claims 1 to 6, comprising: Flake few-layer graphite; nickel-iron layered double hydroxide enrichment micro-areas distributed on the surface and edge areas of the flaky few-layer graphite; And CoFe 2 O 4 nano particles which are mainly distributed on the surface of the nickel-iron layered double hydroxide enrichment micro region and/or the peripheral region of the enrichment micro region; Wherein, a hierarchical heterogeneous interface regulation and control region which is formed by sequentially contacting the lamellar less-layer graphite, the ferronickel layered double hydroxide and the CoFe 2 O 4 is formed in a local area.
8. The use of the magneto-dielectric synergistic wave-absorbing composite material as claimed in claim 7 for the preparation of wave-absorbing coatings, structural wave-absorbing patches or electromagnetic radiation-resistant fabrics.

Description

Hierarchical heterogeneous interface magnetic-dielectric cooperative wave-absorbing material, preparation method and application Technical Field The invention belongs to the technical field of preparation of electromagnetic wave absorbing materials, and particularly relates to a hierarchical heterogeneous interface magneto-dielectric synergistic wave absorbing material, a preparation method and application. Background The existing magneto-dielectric cooperative wave absorbing material is used for realizing electromagnetic wave attenuation by combining magnetic particles with a carbon-based conductive material. The ferrite such as CoFe 2O4 has good magnetic loss capability, and the graphene or few-layer graphite has high conductivity and multiple scattering capability, so that the two are compounded by a common technical route. However, this technical route still has the following inherent drawbacks: (1) When the magnetic particles are in direct contact with the high-conductivity carbon skeleton, a local excessively strong conductive network is easily formed, so that impedance matching is poor. (2) The magnetic particles are randomly distributed on the surface of the carbon material, are easy to agglomerate, cannot form an ordered heterogeneous interface structure, and have limited interface polarization effect; (3) The multicomponent random blending or disordered composite mode can not realize the accurate regulation and control of the spatial distribution of each component, and is difficult to stably construct an effective interface structure. In order to solve the above problems, the prior art attempts to introduce intermediate components such as Layered Double Hydroxide (LDH), however, the prior technical solution of introducing LDH still adopts a multicomponent blending or one-step compounding mode, and the spatial distribution relationship between LDH and magnetic particles and between LDH and carbon skeleton is still not clear, so that the problems of disordered interface and impedance mismatch cannot be effectively solved. Therefore, it is necessary to provide a composite material capable of forming a local-level heterogeneous interface regulatory region between a two-dimensional conductive skeleton and magnetic particles and a method for preparing the same. Disclosure of Invention The invention aims to overcome the defects of the prior art, realizes the cooperative enhancement of magnetic loss and dielectric loss by sequentially controlling the technical scheme of constructing the local-level heterogeneous interface regulation region, remarkably improves the impedance matching characteristic of the material and obtains the broadband efficient electromagnetic wave absorption performance. The invention provides a preparation method of a hierarchical heterogeneous interface magneto-dielectric cooperative wave-absorbing material, which comprises the following steps: Step 1, placing expanded graphite in a water/alcohol mixed solvent containing a nonionic surfactant for liquid phase shearing treatment, and obtaining a lamellar few-layer graphite dispersion liquid after centrifugal separation; Step 2, placing the flaky few-layer graphite dispersion obtained in the step 1 into a reaction system containing a nickel source, an iron source and a precipitant, and reacting under alkaline conditions to ensure that nickel-iron layered double hydroxide nano-sheets preferentially grow on the surface and edge active sites of the flaky few-layer graphite to obtain a composite matrix dispersion with nickel-iron layered double hydroxide enriched micro-areas; Step 3, adding a precursor solution containing a cobalt source and an iron source into the composite matrix dispersion liquid obtained in the step 2, and under the stirring condition, enabling Co and Fe precursors to be preferentially distributed on the surface of the nickel-iron layered double hydroxide enrichment micro-area and/or the peripheral area of the enrichment micro-area, and subjecting the cobalt-iron layered double hydroxide enrichment micro-area to precipitation control or hydrothermal treatment to enable CoFe 2O4 nano particles to be generated in situ or be preferentially deposited on the surface of the nickel-iron layered double hydroxide enrichment micro-area; and 4, separating, washing and drying the composite system obtained in the step 3 to obtain the magneto-dielectric synergistic wave-absorbing composite material. Preferably, in the step 1, the thickness of the flaky fewer-layer graphite is less than 5 nm and the number of layers is less than 10, and the intensity ratio I_D/I_G of a D peak to a G peak in the Raman spectrum of the flaky fewer-layer graphite is less than 0.5. Preferably, in the step 2, the nickel-iron layered double hydroxide enrichment microdomain is composed of nano sheets with a transverse dimension of 20-200 nm and a thickness of 2-10 nm, and the nano sheets are attached to the surface of the lamellar less-layer graphite in a