Regulating Percolation Threshold via Dual Conductive Phases for High-Efficiency Microwave Absorption Performance in C and X Bands

Abstract

The development of high-efficiency microwave absorbers for C and X bands still remains a challenge, limiting the settlement of corresponding electromagnetic pollution and radar stealth. In this work, a reduced graphene oxide (RGO)/Cu/Fe3O4 composite is successfully proposed by a one-step solvothermal method with a GO dispersion content of 5 mL, where Fe3O4 exhibits high magnetic loss from natural resonance at the C band, and Cu nanorods and RGO are introduced as dual conductive phases to produce suitable dielectric properties by regulating the percolation threshold. The results show that the existence of Cu nanorods significantly reduces the conductivity and dielectric loss of the composites, optimizing the coordination of attenuation capacity and impedance matching in the C and X bands. Consequently, the obtained RGO/Cu/Fe3O4 composite shows outstanding microwave absorption performance with the maximum effective absorption bandwidth (EAB) value of 5.2 GHz at a thin thickness of 3.1 mm, which covers 84% of the C band and 46% of the X band (4.64–9.84 GHz). The performance is superior to the vast majority of previous absorbers in the corresponding bands.

High‐Voltage Induced Surface and Intragranular Structural Evolution of Ni‐Rich Layered Cathode

“…This approach, however, leads to a more rapid capacity fade during charge/discharge cycling. [ 7–10 ] Therefore, a thorough understanding of the degradation mechanism of Ni‐rich cathode upon high‐voltage cycling is of great importance for the development of high‐energy‐density LIBs.…”

High Dielectric Fe3O4 and Fe2O3 Nanoparticles Deposited on Graphite Nanosheets for Electromagnetic Wave Absorption

“…In Figure d–f, the frequency dependences of μ′, μ″, and tan δμ for S-150, S-250, S350, and S-450. It has been reported that the natural resonant frequency of soft magnetic Fe 3 O 4 usually occurs at less than 2 GHz. , Magnetic losses in composites are usually related to the natural resonance and eddy currents of ferromagnetic absorbers . The fluctuation of the μ′ and μ″ curves in the whole frequency range means that there are natural resonance, eddy current loss, and exchange resonance, which can enhance the magnetic loss of the composites.…”

Reduced graphene oxide-wrapped Fe–Fe3O4@mSiO2 hollow core–shell composites with enhanced electromagnetic wave absorption properties

“…Specifically, a longer line indicates superior conductivity loss. 35,36 Only semicircles were observed in the Cole-Cole plot of the specimen using Fe 3 O 4 or Fe 3 O 4 @mSiO 2 , as fillers, indicating the dominating role of the Debye relaxation (see Fig. S2, ESI †).…”