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Journal ArticleDOI

Three-dimensional reduced graphene oxide foam modified with ZnO nanowires for enhanced microwave absorption properties

01 May 2017-Carbon (Pergamon)-Vol. 116, Iss: 116, pp 50-58
TL;DR: In this paper, a hierarchical reduced graphene oxide (RGO) foams decorated with in-situ grown ZnO nanowires (ZnO nws ) were realized by a direct freeze-drying and hydrothermal process.
About: This article is published in Carbon.The article was published on 2017-05-01. It has received 499 citations till now. The article focuses on the topics: Absorption (electromagnetic radiation) & Graphene.
Citations
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Journal ArticleDOI
TL;DR: The method of utilizing an external voltage to break the intrinsic dielectric feature by modifying a traditional electronic absorption device is demonstrated for the first time and has great significance in solving the low-frequency electromagnetic interference issue.
Abstract: Nowadays, low-frequency electromagnetic interference (<2.0 GHz) remains a key core issue that plagues the effective attenuation performance of conventional absorption devices prepared via the component-morphology method (Strategy I). According to theoretical calculations, one fundamental solution is to develop a material that possesses a high e' but lower e″. Thus, it is attempted to control the dielectric values via applying an external electrical field, which inducts changes in the macrostructure toward a performance improvement (Strategy II). A sandwich-structured flexible electronic absorption device is designed using a carbon film electrode to conduct an external current. Simultaneously, an absorption layer that is highly responsive to an external voltage is selected via Strategy I. Relying on the synergistic effects from Strategies I and II, this device demonstrates an absorption value of more than 85% at 1.5-2.0 GHz with an applied voltage of 16 V while reducing the thickness to ≈5 mm. In addition, the device also shows a good absorption property at 25-150 °C. The method of utilizing an external voltage to break the intrinsic dielectric feature by modifying a traditional electronic absorption device is demonstrated for the first time and has great significance in solving the low-frequency electromagnetic interference issue.

657 citations

Journal ArticleDOI
01 Dec 2018-Carbon
TL;DR: In this article, the authors discussed the factors of microstructural defects, filler concentration, filler alignment, filler inherent conductivity and the surrounding temperature of carbon nanostructures and their composites.

531 citations

Journal ArticleDOI
TL;DR: In this paper, the authors systematically combed the structures and electromagnetic functions of graphene hybrids, and demonstrated the advances in the microwave response mechanism, including relaxation, charge transport, magnetic resonance, and eddy currents, as well as magnetic-dielectric synergistic effects.
Abstract: Graphene has been long sought-after over the past few decades because of its multiple functions and broad applications in various fields, such as energy, information, medicine, military equipments, and aerospace. In particular, it has been significantly reported in electromagnetic wave absorbing and shielding fields, promoting it as the most cutting-edge topic. Herein, we systematically comb the structures and electromagnetic functions of graphene hybrids. We demonstrate the advances in the microwave response mechanism, including relaxation, charge transport, magnetic resonance, and eddy currents, as well as magnetic-dielectric synergistic effects. Furthermore, our review mainly focuses on graphene-dispersed systems, flexible graphene papers, graphene hybrids, and 3D graphene architectures.

468 citations

Journal ArticleDOI
TL;DR: In this paper, a simple chemical vapor deposition (CVD) route for the direct growth of edge-rich graphene (ERG) with tailored structures and tunable dielectric properties in porous Si3N4 ceramics using only methyl alcohol (CH3OH) as precursor is reported.
Abstract: High-performance graphene microwave absorption materials are highly desirable in daily life and some extreme situations. A simple technique for the direct growth of graphene as absorption fillers in wave-transmitting matrices is of paramount importance to bring it to real-world application. Herein, a simple chemical vapor deposition (CVD) route for the direct growth of edge-rich graphene (ERG) with tailored structures and tunable dielectric properties in porous Si3N4 ceramics using only methyl alcohol (CH3OH) as precursor is reported. The large O/C atomic ratio of CH3OH helps to build a mild oxidizing atmosphere and leads to a unique structure featuring open graphite nanosteps and freestanding nanoplanes, endowing the ERG/Si3N4 hybrid with an appropriate balance between good impedance matching and strong loss capacity. Accordingly, the prepared materials exhibit superior electromagnetic wave absorption, far surpassing that of traditional CVD graphene and reduced graphene oxide-based materials, achieving an effective absorption bandwidth of 4.2 GHz covering the entire X band, with a thickness of 3.75 mm and a negligibly low loading content of absorbents. The results provide new insights for developing novel microwave absorption materials with strong reflection loss and wide absorption frequency range.

417 citations

References
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Journal ArticleDOI
TL;DR: An overview of the synthesis, properties, and applications of graphene and related materials (primarily, graphite oxide and its colloidal suspensions and materials made from them), from a materials science perspective.
Abstract: There is intense interest in graphene in fields such as physics, chemistry, and materials science, among others. Interest in graphene's exceptional physical properties, chemical tunability, and potential for applications has generated thousands of publications and an accelerating pace of research, making review of such research timely. Here is an overview of the synthesis, properties, and applications of graphene and related materials (primarily, graphite oxide and its colloidal suspensions and materials made from them), from a materials science perspective.

8,919 citations

Journal ArticleDOI
01 Aug 2012-Carbon
TL;DR: In this paper, the state-of-the-art status of the reduction of GO on both techniques and mechanisms is reviewed, where the reduction process can partially restore the structure and properties of graphene.

4,187 citations

Journal ArticleDOI
TL;DR: The broadband and tunable high-performance microwave absorption properties of an ultralight and highly compressible graphene foam (GF) are investigated and it is shown that via physical compression, the microwave absorption performance can be tuned.
Abstract: The broadband and tunable high-performance microwave absorption properties of an ultralight and highly compressible graphene foam (GF) are investigated. Simply via physical compression, the microwave absorption performance can be tuned. The qualified bandwidth coverage of 93.8% (60.5 GHz/64.5 GHz) is achieved for the GF under 90% compressive strain (1.0 mm thickness). This mainly because of the 3D conductive network.

1,533 citations

Journal ArticleDOI
TL;DR: Owing to the magnetic-dielectric synergistic effect, the obtained CoNi@SiO2 @TiO2 microspheres exhibit outstanding microwave absorption performance with a maximum reflection loss of -58.2 dB and wide bandwidth of 8.1 GHz.
Abstract: The synthesis of CoNi@SiO2 @TiO2 core-shell and CoNi@Air@TiO2 yolk-shell microspheres is reported for the first time. Owing to the magnetic-dielectric synergistic effect, the obtained CoNi@SiO2 @TiO2 microspheres exhibit outstanding microwave absorption performance with a maximum reflection loss of -58.2 dB and wide bandwidth of 8.1 GHz (8.0-16.1 GHz, < -10 dB).

1,409 citations

Journal ArticleDOI
TL;DR: Chemical graphitized r-GOs, as the thinnest and lightest material in the carbon family, exhibit high-efficiency electromagnetic interference shielding at elevated temperature, attributed to the cooperation of dipole polarization and hopping conductivity.
Abstract: Chemical graphitized r-GOs, as the thinnest and lightest material in the carbon family, exhibit high-efficiency electromagnetic interference (EMI) shielding at elevated temperature, attributed to the cooperation of dipole polarization and hopping conductivity. The r-GO composites show different temperature-dependent imaginary permittivities and EMI shielding performances with changing mass ratio.

1,358 citations