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Ultrathin flexible electrospun carbon nanofibers reinforced graphene microgasbags films with three-dimensional conductive network toward synergetic enhanced electromagnetic interference shielding

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Journal of Materials Science & Technology 2022年第16期111卷 57-65页

作者： Likui Zhang Yao Chen Qian Liu Wenting Deng Yaoqun Yue fanbin meng Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

In recent years,graphene-based composite films have been greatly developed in the field of electromagnetic shielding interference(EMI).However,it is still a huge challenge to prepare graphene-based composite films with excellent mechanical properties,conductivity and electromagnetic shielding *** this work,we adopted a facile and effective method by annealing the alkali-treated polyacrylonitrile(aPAN)nanofibers reinforced graphene oxide(GO)composite films at 2000°C to obtain graphene-carbon nanofibers composite films(GCFs).Microscopically,carbon nanofibers(CNFs)were intercalated into the graphene sheets,and microgasbags structure was formed during the heat treatment *** special structure makes GCFs have superior tensile strength(10.4 MPa)at 5%*** repeated folding over1000 times,the films still demonstrate excellent structural integrity and flexibility ***,the graphene-based composite films with 10 wt%a PAN nanofibers exhibit an extremely low density of about 0.678 g/cm^(3)and excellent electrical conductivity of 1.72×10^(5)S/***,an outstanding electromagnetic shielding effectiveness(SE)of 55–57 d B was achieved,and the corresponding value of the specific SE/thickness can reach 67,601–70,059 d B·cm^(2)/g,which is the highest among reported graphenebased shielding *** significant electromagnetic shielding performance is due to the synergistic enhancement effect brought by the excellent conductivity of carbon nanofibers and graphene,the formed effective conductive network and the microgasbags *** simulation further clarified that the underlying mechanism should be mainly attributed to the conduction loss and multiple reflections caused by the special structure of *** work will provide new solutions for low density,high flexibility and excellent electromagnetic shielding properties materials in the next generation of foldable and wearable electronics.

关键词： Graphene-based composite films Mechanical properties Electromagnetic shielding Electromagnetism simulation Electromagnetic interference shielding mechanism

Multiaxial electrospun generation of hollow graphene aerogel spheres for broadb and high-performance microwave absorption

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Nano Research 2020年第2期13卷 477-484页

作者： Tian Li Dandan Zhi Yao Chen Bing Li Zuowan Zhou fanbin meng Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong University Chengdu 610031China Shandong Qiangjunwei Intelligent Equipment Co.LTD Yantai 264000China

Although graphene aerogels(GA)have been attracted great attention,the easy-operation and large-scale production of GA are still ***,most GA have a monolith-like appearance,limiting their application-specific ***,we highlight graphene aerogel spheres with controllable hollow structures(HGAS)that are delicately designed and manufactured via coaxial electrospinning coupled with freeze-drying and *** HGAS exhibit a spherical configuration at the macroscale,while the construction elements of graphene on the microscale showing an interconnected radial microchannel *** ball-in-ball graphene aerogel spheres(BGAS)are obtained by reference to the triaxial electrospinning *** as-prepared spheres possess the controllable integrated conductive networks,leading to the effective dielectric loss and impedance matching thus bringing on high-performance microwave *** as-obtained HGAS shows a minimum reflection loss of-52.7 dB and a broad effective absorption bandwidth(f)of 7.0 GHz with thickness of 2.3 ***,the fe reaches 9.3 GHz for BGAS with thickness of 3.4 *** superior microwave absorption of HGAS and BGAS confirms combination of multiaxial electrospinning and freeze-drying on the multiscale is an effective strategy for scalable fabrication of advanced *** functional graphene aerogel spheres.

关键词： multiaxial electrospinning hollow graphene aerogel spheres hierarchical porous structures electromagnetic performance

Design of novel RGO/2D strip-like ZIF-8/DMAOP ternary hybrid structure towards high-efficiency microwave absorption, active and passive anti-corrosion, and synergistic antibacterial performance

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Nano Research 2024年第3期17卷 913-926页

作者： Tanlin Chen Yingrui Tian Zihao Guo Yao Chen Qing Qi fanbin meng Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Shenzhen Institute of Southwest Jiaotong University Shenzhen 518000China

In order to meet the requirements of the marine environment for microwave absorption(MA)materials,we put forward the strategy of constructing multi-functional composite materials,which integrate microwave absorption,anti-corrosion,and antibacterial ***,graphene oxide(GO)was used as a template to induce the growth of zeolitic imidazolate framework-8(ZIF-8),simultaneously as a two-dimensional(2D)nanocontainers to load corrosion inhibitors to achieve pH-responsive and self-healing ***,quaternary ammonium salt(dimethyl octadecyl(3-trimethoxylsilyl propyl)ammonium chloride(DMAOP))and sodium ascorbate(VCNa)were introduced to achieve synergistic antibacterial activity and the reduction of *** 2D strip-like structure of ZIF-8 was due to the confined growth induced by the electrostatic attraction between ZIF-8 and GO *** as-obtained reduced GO(RGO)/ZIF-8/DMAOP5 exhibited excellent microwave absorption(MA)properties,with a minimum reflection loss(RL)value of-47.08 dB at 12.73 GHz when the thickness was 2.8 ***,the effective absorption bandwidth reached 6.84 *** soaking in 3.5%NaCl solution for 35 days,the RGO/ZIF-8/DMAOP5-0.7%coating still achieved an impedance value of 4.585×107Ω·cm^(2) and a protective efficiency of 99.994%,providing superior anti-corrosion *** addition,fantastic antibacterial activity was obtained,with the antibacterial rates of RGO/ZIF-8/DMAOP_(10) reaching 99.39%and 100%against Escherichia coli and Staphylococcus *** work could open new avenues towards the development of a new generation of multifunctional MA materials.

关键词： two-dimensional(2D)strip-like zeolitic imidazolate framework-8(ZIF-8) microwave absorption active and passive anti-corrosion antibacterial

Wheat straw-derived magnetic carbon foams: In-situ preparation and tunable high-performance microwave absorption

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Nano Research 2019年第6期12卷 1423-1429页

作者： Guangjun Gou fanbin meng Huagao Wang Man Jiang Wei Wei Zuowan Zhou Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Recently,biomass-derived three-dimensional (3D) porous carbon materials have been gaining more interest as promising microwave absorbers due to their low cost,vast availability,and ***,a novel 3D interconnected porous magnetic carbon foams are in-situ synthesized via a combination of sol-gel and carbonization process with wheat straw as the carbon source and FeCl3·6H2O as the magnetic regulating *** the process of foams formation,the lignocelluloses from the steam-exploded wheat straw are converted into interconnected carbon sheet networks with hierarchical porous structures,and the precursor FeCl3·6H2O is converted into magnetic nanoparticles uniformly embedded in the porous carbon *** generated magnetic nanoparticles are benefit to enhance the interface polarization and magnetic loss ability to improve the efficient complementarities between the dielectric and magnetic loss,thus increasing the impedance *** obtained sample treated at 600 ℃ displays the best microwave absorption (MA) *** presents a minimal reflection loss (RL) of-43.6 dB at 7.1 GHz and the effective bandwidth (RL <-10 dB) is 3.3 GHz with the thickness of 4.7 *** 3D porous structure,multi-interfaces and the synergy of dielectric loss and magnetic loss make great contribution to the outstanding MA performance.

关键词： wheat straw magnetic biomass carbon foams microwave absorption interface polarization impedance matching

Failure characteristics of Ag-SnO_2 contact material in AC level

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Rare Metals 2008年第1期27卷 18-21页

作者： meng fanbin LU Jianguo ZHU Yongqing LU Ningyi CHEN Zhichao HUANG Qiutao Electrical Apparatus Institute Hebei University of Technology Tianjin 300130 China Hongfa Electroacoustlc Co. Ltd. Xiamen 361021 China

The failure characteristics of the contact material Ag-SnO2 were investigated by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,and X-ray energy dispersive spectroscopy（EDS）.Phase analysis showed that there were Ag,SnO2,and Sn on the contact surfaces at the time of failure under the load condition of 30 A and 220 V（AC）,which means that SnO2 decomposed in *** the contacts were tested under airproof ambient condition,half-spherical bulges came into being on the contact surfaces,which resulted in early failure and dispersive *** half-spherical bulges were not found when the contacts were tested under open ambient *** temperature change of the contacts during the life testing under airproof ambient condition was different from that under open ambient condition.

关键词： contact materials electric contact failure analysis relays

Generation of graphene-based aerogel microspheres for broadband and tunable high-performance microwave absorption by electrospinning-freeze drying process

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Nano Research 2018年第5期11卷 2847-2861页

作者： fanbin meng Huagao Wang Wei Zijian Chen Tian Li Chunyuan Li Yu Xuan Zuowan Zhou Key Laboratory of Advanced Technologies of Materials (Ministry of Education) School of Materials Science and Engineering Southwest Jiaotong University Chengdu 610031 China

Despite recent progress in the synthesis and application of graphene-based aerogels, some challenges such as scalable and cost-effective production, and miniaturization still remain, which hinder the practical application of these materials. Here we report a large-scale electrospinning method to generate graphene-based aerogel microspheres （AMs）, which show broadband, tunable and high-performance microwave absorption. Graphene/Fe3O4 AMs with a large number of openings with hierarchical connecting radial microcharmels can be obtained via electrospinning-freeze drying followed by calcination. Importantly, for a given Fe3O4：graphene mass ratio, altering the shape of aerogel monoliths or powders into aerogel microspheres leads to unique electromagnetic wave properties. As expected, the reflection loss of graphene/Fe3O4 AMs-1：1 with only 5 wt.% absorber loading reaches -51.5 dB at 9.2 GHz with a thickness of 4.0 mm and a broad absorption bandwidth （RL 〈-10 dB） of 6.5 GHz. Furthermore, switching to coaxial electrospinning enables the fabrication of SiO2 coatings to construct graphene/Fe3O4@SiO2 core-shell AMs. The coatings influence the electromagnetic wave absorption of graphene/Fe3O4 AMs significantly. In view of these advantages, we believe that this processing technique may be extended to fabricate a wide range of unique graphene-based architectures for functional design and applications.

关键词： electrospun graphene-based aerogel microspheres electromagnetic wave absorption impedance matching ultralow loading content

High-purity helical carbon nanotubes by trace-water- assisted chemical vapor deposition： Large-scale synthesis and growth mechanism

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Nano Research 2018年第6期11卷 3327-3339页

作者： fanbin meng Ying Wang Qiang Wang Xiaoling Xu Man Jiang Xuesong Zhou Ping He Zuowan Zhou Key Laboratory of Advanced Technologies of Materials (Ministry of Education) School of Materials Science and Engineering Southwest Jiaotong University Chengdu 610031 China Zhonghao Heiyuan Research Institute of Chemical Industry Zigong 643201 China

Helical carbon nanotubes （HCNTs） are highly desirable due to their unique geometrical elegance and inherent physical properties; however, high-efficiency synthesis of high-purity HCNTs with high yield and full elucidation of their growth mechanism remains challenging. Traditional methods to achieve the high-yield growth of HCNTs mainly focus on controlling the size of catalytic particles. Herein, we found that addition of trace water greatly benefits large-scale synthesis of HCNTs. Uniform HCNTs with - 100% purity can be obtained, and the yield of HCNTs can reach ~ 8,078% in a run of 6 h, much higher than that obtained without trace water and any of the reported yields. Experiments and theoretical simulations are performed to reveal that the trace water can react with the dangling bond on carbon, thus inhibiting the generation of amorphous species. Furthermore, the trace water can enhance the anisotropy of the catalyst surface. This results in different segregation rates of carbon atoms coming out of different crystal planes and further periodic mismatch of the graphite layers, thus leading to the formation of HCNTs. Therefore, this new and efficient method is promising for practical, large-scale production of HCNTs.

关键词： helical carbon nanotubes trace water assist high yield and purity first-principles study growth mechanism

Multifunctional aramid nanofibers reinforced RGO aerogels integrated with high-efciency microwave absorption, sound absorption and heat insulation performance

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Journal of Materials Science & Technology 2022年第35期130卷 166-175页

作者： Qian Liu Liang Tang Jinzhe Li Yao Chen Zhengkang Xu Jiatong Li Xinyu Chen fanbin meng Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Shenzhen Institute of Southwest Jiaotong University Shenzhen 518000China

Although lightweight and three-dimensional(3 D) graphene aerogels are highly desirable for microwave absorption(MA) due to their high porosity,specific surface area,and 3 D conductive network,it still remains a large challenge to construct a multifunctional application framework to quickly adapt to the complex practical environment,making it to be efficiently applied in a variety of complex ***,multifunctional aramid nanofibers(ANFs) reinforced reduced graphene oxide aerogels(RGO@ANF) have been achieved by in-situ gel reaction,freeze-drying,and thermal annealing *** introduced ANFs in RGO aerogels can prevent the graphene sheets from over-stacking and enhance the connectivity of cell walls,thus leading to excellent compression resistance,MA,sound absorption,and thermal insulation *** 70% strain,the maximum compressive stress of RGO@ANF aerogel reaches78.8 kPa,and reversible compressibility with reliable resistance to fatigue for 100 compressive cycles at20% ***,the RGO@ANF aerogel exhibit a minimum reflection loss(RL_(min)) of-56.5 dB and a maximum effective absorption bandwidth(EAB) of 7.0 GHz at a thickness of 2.8 mm,basically covering the X and Ku ***,the hybrid aerogel exhibited excellent sound absorption with an average absorption coefficient> 0.56 at 2-6 kHz and good thermal insulation performance with low thermal conductivity of about 49.18 mW *** integrated graphene aerogels with such multifunctional performances hold a great promise for applications such as MA,sound absorption,and heat insulation.

关键词： Graphene-based aerogels Reversible Compressibility Microwave absorptio Heat insulation Sound absorption

Influence of stresses on martensitic transformation in ferromagnetic shape memory Ni_(50)Mn_(19)Fe_6Ga_(25) ribbons

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Science China(Technological Sciences) 2004年第6期47卷 710-715页

作者： meng fanbin LI Yangxian LIU Heyan QU Jingping LIU Zhuhong CHEN Jinglian WU Guangheng School of Mechanical Science and Engineering Hebei University of TechnologyTianjin 300130China State Key Laboratory for Magnetism Institute of PhysicsChinese Academy of SciencesBeijing 100080China

The influence of stresses on martensitic transformation in Ni50Mn19Fe6Ga25 melt-spun ribbons was studied. X-ray diffraction examination shows that the ribbon has a pure cubic L21 phase at room temperature and that the ribbon surface exhibits [100] preferentially oriented texture, while the [110] axis is about 45° tilted from the normal of the ribbon. By calculating the d spacing at different angles with the length direction of the ribbon, the tension was observed. It was found that the direction of the stress was along [010] direction of the oriented textured grains. During cooling, there is no obvious structural transition observed in as-spun ribbons. However, when the ribbons were annealed at 900 K for 24 h, the tension along [010] direction disappeared and the structural transition from cubic to tetragonal occurred obviously during cooling. It indicates that it is the tension along [010] direction to suppress the martensitic transformation in the as-spun ribbons.

关键词： stress martensitic transformation ferromagnetic shape memory alloy