Enhanced Electromagnetic Microwave Absorption Performance of Lightweight Bowl-like Carbon Nanoparticles

Abstract

Rational structure design of microwave absorption material (MAM) is of fundamental significance in terms of enhancing the electromagnetic microwave absorption performance and deeply understanding the specific correlation between the material structure and its electromagnetic microwave absorption (EMA) performance. Here, bowl-like carbon nanoparticles (BLCNs) as novel MAM have been successfully fabricated via calcination of bowl-like polydopamine. Interestingly, BLCNs have exhibited dramatically enhanced EMA performance with a minimum reflection loss of −45.3 dB and an effective bandwidth of below −10 dB in the wide range of 4.2 GHz, implying the unique critical role of the microstructure in adjusting the EMA performance. Our work not only paves an attractive way for the design of advanced and lightweight MAM, but also provides valuable insights into the relationships between the material structure and its EMA performance.

Multidimension‐Controllable Synthesis of MOF‐Derived Co@N‐Doped Carbon Composite with Magnetic‐Dielectric Synergy toward Strong Microwave Absorption

“…[ 16 ] The C1s XPS spectra for the Co@NCNT‐o products were deconvoluted into four signals with binding energies of 284.3, 285.2, 286.5, and 288.6 eV corresponding to CC/CC, CN, CO, and CO species, respectively (Figure S9, Supporting Information). [ 17 ] Accordingly, the XPS results are consistent with the expected surface composition, demonstrating successful hybridization with N‐doped CNT.…”

Preparation and Characterization of Copper Chromium Oxide Nanoparticles Using Modified Sol‐Gel Route and Evaluation of Their Microwave Absorption Properties

“…The microwave absorbing properties of materials have been investigated according to the transmission line theory equation. The reflection losses of absorbers were obtained from equation where Z 0 is the intrinsic impedance of free space (377 Ω) and Z in equal to the intrinsic impedance of absorber, given by the equation where μ r, ϵ r, f , d , and c are the complex permeability, complex permittivity, frequency, thickness of absorber, and velocity of light in the free space, respectively . The simulation of matching thicknesses and microwave absorption curves of CuCr 2 O 4 /silicone rubber or PVDF as well as modified CuCr 2 O 4 /silicone rubber or PVDF nanocomposites in the x and ku‐band frequency with thicknesses of 1.5, 2.0, 2.5, and 3.0 mm have been presented in Figure .…”

“…The relative complex permittivity and permeability of nanocomposites from 8.2 to 18 GHz frequency were investigated in the Figure . The complex permittivity and permeability are originated from and equations where ϵ ′ and ϵ ″ are the real and imaginary parts of permittivity and μ ′ and μ ″ are the real and imaginary parts of permeability . The spectra illustrated more resonance peaks within the PVDF polymeric matrix, originated from dipole interactions between the fluorine unpaired electrons and the surface of nanoparticles.…”

Dopamine-derived cavities/Fe3O4 nanoparticles-encapsulated carbonaceous composites with self-generated three-dimensional network structure as an excellent microwave absorber

“…Those carbonaceous composites FC-700 and HFC-X all present noticeable I D /I G values (>1.6) in comparison to other carbonbased microwave absorption materials reported in related papers. 26,28,32 A high value that means more defects in the carbon is likely to largely inspire defect and dipole polarization, which give rise to the absorption properties.…”

“…The solid-void interfaces can generate interfacial polarization, multiple reections and scattering in the presence of microwaves and then attenuate the microwaves. 25,26 Nevertheless, there are limited reports on microwave absorption by SA. Moreover, Fe 3+ can be cross-linked with alginate macromolecules when SA gels and subsequently, magnetic Fe 3 O 4 nanoparticles that make a signicant contribution to magnetic dissipation will be generated in situ during the carbonization process.…”