Improved impedance matching by multi-componential metal-hybridized rGO toward high performance of microwave absorption

Abstract

Microwave-absorbing materials with good microwave absorption performance are of great interest for military applications and human health, which is threatened by electromagnetic radiation pollution. Herein, the design and synthesis of multi-componential metal-hybridized graphene composites via freeze drying and pyrolysis of ferrocene hydrazone complex precursor are reported. Various magnetic nanoparticles are loaded on reduced graphene oxide (rGO) via controlling their pyrolysis temperature. The complex electromagnetic parameters of these hybrids are therefore regulated by the hybrid components. Among them, rGO hybridized by the sea-island-like Fe2O3/Fe3O4/FeNi3 multi-componential metals shows a good balance of dielectric and magnetic constants. Thus, the improved impedance matching with free space brings about a superior electromagnetic wave absorption performance, especially on the effective absorption bandwidth. The minimum reflection loss (RL) of the hybrids is as low as −40.3 dB at 11 GHz with the RL bandwidth of −10 dB being 4.55 GHz (from 9.25 to 13.8 GHz).

Reduced Graphene Oxide/Barium Ferrite Ceramic Nanocomposite Synergism for High EMI Wave Absorption

“…The 25 wt % TCRGO/BF and TCRGO/MAG ceramic nanocomposites exhibit improved microwave absorption performance due to the effective dissipation of electromagnetic waves that enter the interiors of these absorbers, with the 25 wt % TCRGO/BF showing particularly advantageous performance, surpassing other samples. , A high attenuation value demonstrates a synergistic enhancement of dielectric and magnetic energy loss, leading to a more effective absorption of the wave by the ceramic nanocomposite . Additionally, the effective absorption percentage, denoted as A eff , is a metric used to assess the efficiency of an EMI shielding material in absorbing EMI.…”

Construction and application of carbon aerogels in microwave absorption

“…Generally, matching the value of ε r to μ r is beneficial for achieving good impedance matching. 127,128 where Z in indicates the impedance of the absorption material, and Z 0 indicates the impedance of free space. d , f , c are the thickness of the absorption material, frequency of incident electromagnetic wave and the speed of light.…”

“…Generally, matching the value of e r to m r is beneficial for achieving good impedance matching. 127,128…”

“…9b. 128 The attenuation constants are, on the whole, linear with electromagnetic wave frequencies. The peak marked by the arrow in Fig.…”

Polypyrrole/Schiff Base Composite as Electromagnetic Absorbing Material with High and Tunable Absorption Performance

“…Polypyrrole (PPy), one of the most commonly used conductive polymers, has attracted extensive research in the field of electromagnetic absorption [ 9 ]. However, according to the free electron theory, conductive PPy has high permittivity, leading to mismatching between the dielectric constant and permeability, to be more precise, a mismatching in impedance, thus affecting its microwave absorption performance [ 10 ]. Therefore, many composites composed of PPy and magnetic metal compounds have been investigated, including Fe 3 O 4 [ 11 ], Co 3 O 4 [ 12 ], MoS 2 [ 13 ], ZnFe 2 O 4 [ 14 ], Ni [ 15 ], and other designed PPy magnetic metal composites.…”