Lightweight hollow carbon nanospheres with tunable sizes towards enhancement in microwave absorption

Zhou, Chen; Geng, Sai; Xu, Xiuwen; Wang, Tihong; Zhang, Liqiang; Tian, Xiaojuan; Yang, Fan; Yang, Haitao; Li, Yongfeng

doi:10.1016/j.carbon.2016.07.015

Cited by 232 publications

(97 citation statements)

References 44 publications

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“…3c), much better than that of similar carbon absorbers (Table 1). [34][35][36][37][38][39][40] Further increasing the carbonization temperature decreased the span of frequencies that was effectively absorbed: at a thickness of 1.5 mm, S-1000 effectively absorbed radiation spanning only 3.2 GHz (Fig. 3d).…”

Section: Characterizationsmentioning

confidence: 99%

“…9 In recent years, the rapid development of electronic, wireless communication techniques has resulted in increasing levels of electromagnetic pollution. [10][11][12] Finding materials that can eliminate these unwanted electromagnetic waves has been of general interest. Amorphous carbon has been selected as an electromagnetic absorber due to its moderate conductivity, which can balance its impedance matching and electromagnetic attenuation ability and thus lead to its displaying highperformance absorption properties.…”

Section: Introductionmentioning

confidence: 99%

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Development of a hollow carbon sphere absorber displaying the multiple-reflection effect to attenuate electromagnetic waves

Sun

Wang

et al. 2017

RSC Adv.

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The development and use of hollow amorphous carbon spheres has been considered to be an efficient strategy to combat severe electromagnetic interference. In the current work, hollow carbon spheres were treated at various high temperatures to improve their graphitization levels and conductivity loss abilities in an attempt to best eliminate the unwanted electromagnetic wave. Of the various samples tested, the hollow carbon spheres obtained at 900 C showed the best and excellent electromagnetic absorption, with a reflection loss value (RL min ) of up to À23.0 dB and the ability to effectively absorb frequencies spanning a range of 4.4 GHz, when using a sample layer with a thickness of only 1.5 mm. A mechanism for the electromagnetic absorption was proposed. Besides the strong conductivity, the occurrence of multiple reflections of electromagnetic waves in the interior void was indicated to strengthen the attenuation of the electromagnetic wave.

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Section: Characterizationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of a hollow carbon sphere absorber displaying the multiple-reflection effect to attenuate electromagnetic waves

Sun

Wang

et al. 2017

RSC Adv.

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“…The two broad peaks positioned at 2q ¼ 24 and 42 correspond to the reections of (002) and (100) planes of graphite, respectively. 22,29,35 Since the peak intensity of d 002 plane in CAs is weak, it is concluded that the CAs structure consists of low degree of crystallinity.…”

Section: Xrd Analysismentioning

confidence: 99%

Electromagnetic and microwave absorption characteristics of PMMA composites filled with a nanoporous resorcinol formaldehyde based carbon aerogel

2018

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Nanostructured carbons have opened up new perspectives in fields of electromagnetic (EM) applications.The present study aims at the processing of microwave absorbing (MA) materials based on carbon aerogels (CAs) in polymethyl methacrylate (PMMA) matrix to be used in X-band frequency. CAs were synthesized by carbonization of a sol-gel derived organic gel from resorcinol and formaldehyde as starting materials. Microwave attenuation properties of the prepared composites were investigated in terms of CAs particle size distribution (PSD) and mass fraction. To do so, the optimal PSD was initially determined by assessing the EM attenuation performance of the CAs/PMMA composites with constant mass loading (10 wt%) and differing particle sizes. Next, the EM properties of the selected CAs with the optimal particle size was measured as a function of mass fraction varying from 1 to 15 wt% in order to obtain a highly efficient CAs based MA. The results indicate that the dielectric loss of CAs composites can be enhanced by optimizing the PSD as well as the mass fraction of CAs. The effective absorption bandwidth of composites containing 10 wt% of CAs exceeded 3.7 GHz at a very thin thickness of 1.9 mm indicating that these materials present advantages as microwave absorbers.

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“…Hence, excellent EM wave absorption materials are urgently needed to reduce the radiation impact of EM waves. It is widely accepted that ideal EM wave absorption materials should not only possess a wide absorption bandwidth but also exhibit good thermal stability and have a light weight . Typically, traditional EM absorption materials are composed of an EM wave transparent phase (A phase, matrix) and a lossy phase (B phase, absorption agent).…”

Section: Introductionmentioning

confidence: 99%

“…The microstructure of the absorption agent has a great influence on the EM absorption performance. Recently, special microstructures with large surface areas, such as a hollow structure, core‐shell structure, yolk‐shell structure and mesoporous hollow structure, have been developed to enhance EM absorption ability. Among them, the mesoporous hollow structure has attracted great attention due to its large surface areas and highly porous structure.…”

Section: Introductionmentioning

confidence: 99%

Interface evolution of a C/ZnO absorption agent annealed at elevated temperature for tunable electromagnetic properties

Yin

et al. 2019

J Am Ceram Soc

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Excellent electromagnetic (EM) wave absorption agents that attenuate EM waves by mechanisms based on impedance matching, conductive loss and polarization loss instead of destructive interference are urgently needed but remain challenging. Here, an EM wave absorption agent with a tailorable heterogeneous interface is designed and prepared by the in situ growth of ZnO nanoparticles on the surface of mesoporous carbon hollow microspheres (PCHMs@ZnO) via hydrothermal synthesis followed by annealing. A controlled interface evolution associated with abundant heterogeneous interfaces plays a crucial role in optimized impedance matching and enhanced interfacial polarization loss. With this method, targeted EM wave absorption agents with an excellent absorption ability that is derived mainly from polarization loss and conductive loss rather than destructive interference are successfully obtained. When the PCHMs@ZnO annealed at 700°C were combined with paraffin, the effective absorption bandwidth of the resultant composites covers the whole X band, and the mean value of reflection loss (RL) reaches −12 dB, exceeding those of other reported ZnO‐based materials. When the thickness of the composites varies from 3.3 to 4.3 mm, the value of the RL is lower than −8 dB in the whole X band. This work provides a promising model for preparing high‐performance EM wave absorption agents.

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Lightweight hollow carbon nanospheres with tunable sizes towards enhancement in microwave absorption

Cited by 232 publications

References 44 publications

Development of a hollow carbon sphere absorber displaying the multiple-reflection effect to attenuate electromagnetic waves

Development of a hollow carbon sphere absorber displaying the multiple-reflection effect to attenuate electromagnetic waves

Electromagnetic and microwave absorption characteristics of PMMA composites filled with a nanoporous resorcinol formaldehyde based carbon aerogel

Interface evolution of a C/ZnO absorption agent annealed at elevated temperature for tunable electromagnetic properties

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