Environment-Stable CoxNiy Encapsulation in Stacked Porous Carbon Nanosheets for Enhanced Microwave Absorption

Liang, Xiaohui; Man, Zengming; Quan, Bin; Zheng, Jing; Gu, Weihua; Zhang, Zhu; Ji, Guangbin

doi:10.1007/s40820-020-00432-2

Cited by 232 publications

(99 citation statements)

References 45 publications

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“…Yet, the continued development of microwave absorbing materials is imperative. These materials are highly utilized in the defense [ 16–22 ] and telecommunications industries, [ 18,23–27 ] as means for reducing radar cross sections for stealth technology, [ 28,29 ] and providing electromagnetic interference shielding for the information processing and transport capabilities in electronic devices. The progression of research and development in the field of MAMs continues to accelerate, and researchers are in need of new methods for materials development and analysis.…”

Section: Figurementioning

confidence: 99%

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Green

Tran

Chen

2020

Adv Materials Inter

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materials development methods do not guarantee results. Yet, the continued development of microwave absorbing materials is imperative. These materials are highly utilized in the defense [16-22] and telecommunications industries, [18,23-27] as means for reducing radar cross sections for stealth technology, [28,29] and providing electromagnetic interference shielding for the information processing and transport capabilities in electronic devices. The progression of research and development in the field of MAMs continues to accelerate, and researchers are in need of new methods for materials development and analysis. One of the most common components integrated into materials systems for microwave absorption is polyaniline. [30-36] This polymer, particularly the protonated Emeraldine Salt variation due to its high conductivity, is a popular material for MAM research and development due the strong dielectric response it demonstrates when irradiated with GHz-range electromagnetic energy. [15] For example, Liu et al. embedded a graphene-polyaniline matrix with nickel ferrite in an attempt to synergistically couple the magnetic properties of the ferrite with the dielectric nature of the matrix. This coupling resulted in a strong microwave interaction and reflection loss of −50.5 dB at 12.5 GHz, with an effective bandwidth of 5.3 GHz. [30] Wang et al. took a similar approach, imbedding a nickel-zinc ferrite into a polyaniline matrix, with a similar goal of coupling the strong dielectric action of the polyaniline material with a magnetic material. The maximal reflection loss realized by these efforts was −41 dB at 12.8 GHz and a 5 GHz effective bandwidth with a material thickness of 2.6 mm. [31] In this study, we demonstrate for the first time a data-driven process for optimizing the microwave absorbing properties of polyaniline. The final reflection loss is maximally reported as −88.54 dB with (f, d) coordinates of (7.0 GHz, 3.8 mm) 5.5 GHz with a 2.1 mm thickness. These results are record-setting for polyaniline-based materials, and the methods used to achieve these experimentally-validated results are thought to be scalable and applicable to the type of research methodologies prevalent in MAM development. As such, this type of data-driven optimization has the potential to revolutionize materials R&D for microwave absorption. The polyaniline materials were synthesized according to standard literature procedures [37] and characterized via X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and Microwave absorbing materials (MAMs) are highly utilized in the defense and telecommunications industries, as means for reducing radar cross sections for stealth technology, and providing electromagnetic interference shielding for the information processing and transport capabilities in electronic devices. Polyaniline materials have attracted enormous attention in the field of MAM development due to their strong dielectric properties. In this manuscript, the strong dielectric action of polyaniline is utilized to demonstrate...

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Section: Figurementioning

confidence: 99%

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Green

Tran

Chen

2020

Adv Materials Inter

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“…At the same time, the ε′ value of the CNA900 sample decreased from 9.32 to 5.47 during the working frequency from 2 to 18 GHz, while the ε″ value decreased from 5.10 to 2.25. It can be found that the ε′ and ε″ values of CNA800 and CNA1000 accompanied with dramatic fluctuations during high frequency range, which can be ascribed to dielectric resonance behavior and dipole polarization caused by particles aggregation 22 . Moreover, the average values of the real (μ′) and imaginary (μ″) permeability of CNA900 are 1.08 and 0.15, separately.…”

Section: Resultsmentioning

confidence: 97%

Extending effective microwave absorbing bandwidth of CoNi bimetallic alloy derived from binary hydroxides

Chen

Zhao

et al. 2020

Sci Rep

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Effectively broadening microwave absorbing frequency of pure magnetic substances remains a huge challenge. Herein, micro-perspective structures can be controlled through a calcination route. Satisfactorily, the composites prepared at the calcination temperature of 900 °C exhibit excellent microwave attenuation performance with a broad working frequency and appropriate paraffin filling ratio. Remarkably, the composites can reach an extremely high reflection loss (RL) value of − 49.79 dB, and the extended effective working frequency range (RL < − 10 dB) of 6.84 GHz can also be obtained. Superb magnetic loss, admirable dielectric loss, sufficient dipole polarization, as well as superior impedance matching should be band together for obtaining ideal microwave absorbers. The CoNi hydroxides derived bimatallic alloy composites were fabricated via a cost-effective and facile synthesis process, and this work aroused inspirations of designing high-performance microwave absorbers for mataining the sustainable development.

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“…With an increase in sample thickness, the maximum RL moved toward the low frequency. The matched frequency ( f m ) and matched thickness ( t m ) can satisfy the equation: [ 15 ]

t_{m} = n c / (4 f_{m} \sqrt{(||, μ_{r})} \sqrt{(||, ε_{r})})

, in which c is the EM wave velocity in free space ( n = 1, 3, 5...). The absorption band (RL less than –20 dB) was over 3–18 GHz, which mainly focused on λ/4.…”

Section: Resultsmentioning

confidence: 99%

“…To achieve thin absorbers, the permeability and permittivity can be improved according to the equation

t_{m} = n λ / 4 = n c / (4 f_{m} \sqrt{|μ_{r}| |ε_{r}|})

. [ 15 ] Numerous studies have been conducted on this issue, and found that the modulation of absorbent dimension, structure, component, defect, and surface‐interface can remarkably increase the permittivity owing to the increased multiple polarizations. [ 16–18 ] In addition, based on Snoek's law

(false(μ_{s} - 1 false) f_{r} = \frac{2}{3} γ \times 4 π M_{s})

, the permeability can be enhanced by selecting magnetic materials as absorbers, combining nonmagnetic absorbers with magnetic materials, [ 19,20 ] inhibiting eddy current effects, [ 21 ] enlarging the anisotropic field, [ 8 ] adding an epactal geometrical field to the scattered spin waves, [ 22 ] etc.…”

Section: Introductionmentioning

confidence: 99%

Simple Salt‐Template Assembly for Layered Heterostructures of C/Ferrite and EG/C/MFe₂O₄ (M = Fe, Co, Ni, Zn) Nanoparticle Arrays toward Superior Microwave Absorption Capabilities

Lü

Shao

et al. 2020

Adv Materials Inter

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carbon, [1] expanded graphite (EG), carbon nanotubes (CNTs), and graphene), dielectric loss materials (ZnO [2] and BaTiO 3), and magnetic loss materials (MFe 2 O 4 , [3] Fe, Co, Ni, and their alloys [4,5]) are generally included. Among them, ferrite materials are widely used as EAMs because of their abundant raw materials, low cost, easy preparation, nontoxicity, and good chemical stability. [3,6] However, their low permittivity and large density render them too thick and heavy to be used in light and thin electronic devices. Besides, EG consisting of sheet-like graphite as an EAM has also attracted much attention. Its excellent properties (low cost, low density, large conductivity, large specific surface area, good antioxidation ability, and big shape anisotropy [6,7]) make it a superb host for nanoparticles. [8] Nevertheless, studies have demonstrated that EG solely used as an EAM hardly meets the high demand of broadband EAMs due to its single conductivity loss and poor impedance matching. Layered C/ferrite nanoparticle array (NPA) and expanded graphite (EG)/C/MFe 2 O 4 (M = Fe, Co, Ni, Zn) NPA heterostructures are synthesized via a simple sodium salt-template method. An array of well-distributed ferrite nanoparticles supported by layered carbon grows simultaneously on the EG surface from metal-oleate complexes. Some dynamic factors are systematically optimized to well adjust the size, content, and morphology of the heterostructures. The heterostructures show good soft magnetic nature with the M s decreasing in the following order: EG/C/γ-Fe 2 O 3 > EG/C/CoFe 2 O 4 > EG/C/NiFe 2 O 4 > EG/C/ZnFe 2 O 4. As microwave absorbers, these heterostructures of EG/C/MFe 2 O 4 NPA exhibit significantly enhanced electromagnetic-wave absorbing capabilities (EWACs) compared with pure EG, EG/γ-Fe 2 O 3 NPA heterostructure, and other C-based composites. Hereinto, EG/C/CoFe 2 O 4 NPA heterostructures exhibit the optimal EWAC with a minimal reflection loss of −49.85 dB at 13.9 GHz and a 1.3 mm coating thickness. The frequency range of 99% absorption is over 2.0-17.0 GHz and the corresponding thickness is 1.10-8.0 mm. The excellent microwave absorption relies on cooperation of double dielectric relaxations, natural resonance, eddy current loss, high attenuation, and appropriate impedance matching. Therefore, layered heterostructures of EG/C/MFe 2 O 4 NPA are promising electromagnetic wave absorbers for practical application.

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Environment-Stable CoxNiy Encapsulation in Stacked Porous Carbon Nanosheets for Enhanced Microwave Absorption

Cited by 232 publications

References 45 publications

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Extending effective microwave absorbing bandwidth of CoNi bimetallic alloy derived from binary hydroxides

Simple Salt‐Template Assembly for Layered Heterostructures of C/Ferrite and EG/C/MFe₂O₄ (M = Fe, Co, Ni, Zn) Nanoparticle Arrays toward Superior Microwave Absorption Capabilities

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Environment-Stable CoxNiy Encapsulation in Stacked Porous Carbon Nanosheets for Enhanced Microwave Absorption

Cited by 232 publications

References 45 publications

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Extending effective microwave absorbing bandwidth of CoNi bimetallic alloy derived from binary hydroxides

Simple Salt‐Template Assembly for Layered Heterostructures of C/Ferrite and EG/C/MFe2O4 (M = Fe, Co, Ni, Zn) Nanoparticle Arrays toward Superior Microwave Absorption Capabilities

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Simple Salt‐Template Assembly for Layered Heterostructures of C/Ferrite and EG/C/MFe₂O₄ (M = Fe, Co, Ni, Zn) Nanoparticle Arrays toward Superior Microwave Absorption Capabilities