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1.
Highly Conductive Ordered Mesoporous Carbon Based Electrodes Decorated by 3D Graphene and 1D Silver Nanowire for Flexible Supercapacitor
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Jian Zhi Wei Zhao Xiangye Liu Angran Chen Zhanqiang Liu Fuqiang Huang 《Advanced functional materials》2014,24(14):2013-2019
Ordered mesoporous carbon (OMC) is considered one of the most promising materials for electric double layer capacitors (EDLC) given its low‐cost, high specific surface area, and easily accessed ordered pore channels. However, pristine OMC electrode suffers from poor electrical conductivity and mechanical flexibility, whose specific capacitance and cycling stability is unsatisfactory in flexible devices. In this work, OMC is coated on the surface of highly conductive three‐dimensional graphene foam, serving as both charge collector and flexible substrate. Upon further decoration with silver nanowires (Ag NWs), the novel architecture of Ag NWs/3D‐graphene foam/OMC (Ag‐GF‐OMC) exhibits exceptional electrical conductivity (up to 762 S cm?1) and mechanical robustness. The Ag‐GF‐OMC electrodes in flexible supercapacitors reach a specific capacitance as high as 213 F g?1, a value five‐fold higher than that of the pristine OMC electrode. Moreover, these flexible electrodes also exhibit excellent long‐term stability with >90% capacitance retention over 10 000 cycles, as well as high energy and power density (4.5 Wh kg?1 and 5040 W kg?1, respectively). This study provides a new procedure to enhance the device performance of OMC based supercapacitors, which is a promising candidate for the application of flexible energy storage devices. 相似文献
2.
Hydrophilic Nanotube Supported Graphene–Water Dispersible Carbon Superstructure with Excellent Conductivity
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Vasilios Georgakilas Athanasios Demeslis Evangelos Ntararas Antonios Kouloumpis Konstantinos Dimos Dimitrios Gournis Mikuláš Kocman Michal Otyepka Radek Zbořil 《Advanced functional materials》2015,25(10):1481-1487
In this work, it is shown that the hydrophilic functionalized multiwall carbon nanotubes (MWCNs) can stabilize a large amount of pristine graphene nanosheets in pure water without the assistance of surfactants, ionic liquids, or hydrophilic polymers. Role of stabilizer is conveyed by highly hydrophilic carbon nanotubes, functionalized by dihydroxy phenyl groups, affording a stable dispersion at concentrations as high as 15 mg mL?1. Such multidimensional (2D/1D) graphene/MWCN hybrid is found to be dispersible also in other polar organic solvents such as ethanol, isopropanol, N,N‐dimethylformamide, ethylene glycol, and their mixtures. High‐resolution transmission microscopy and atomic force microscopy (AFM) including a liquid mode AFM manifest several types of interaction including trapping of multiwalled carbon nanotubes between the graphene sheets or the modification of graphene edges. Molecular dynamic simulations show that formation of an assembly is kinetically controlled. Importantly, the hybrid can be deposited on the paper by drop casting or dispersed in water‐soluble polymers resulting in record values of electrical conductivity (sheet resistance up to Rs ≈ 25 Ω sq?1 for free hybrid material and Rs ≈ 1300 Ω sq?1 for a polyvinilalcohol/hybrid composite film). Thus, these novel water dispersible carbon superstructures reveal a high application potential as conductive inks for inkjet printing or as highly conductive polymers. 相似文献
3.
A kind of graphene‐based nanoporous material is prepared through assembling graphene sheets mediated through polyoxometalate nanoparticles. Owing to the strong interaction between graphene and polyoxometalate, 2D graphene sheets with honeycomb‐latticed carbon atoms could assemble into a porous structure, in which 3D polyoxometalate nanoparticles serve as the crosslinkers. Nitrogen and hydrogen sorption analysis reveal that the as‐prepared graphene‐based hybrid material possesses a specific surface area of 680 m2 g?1 and a hydrogen uptake volume of 0.8?1.3 wt%. Infrared spectrometry is used to probe the electron density changes of polyoxometalate particle in the redox‐cycle and to verify the interaction between graphene and polyoxometalate. The as‐prepared graphene‐based materials are further characterized by Raman spectroscopy, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. 相似文献
4.
Monomeric gold (Au) and silver (Ag) nanoparticle (NP) arrays are self‐assembled uniformly into anodized aluminium oxide (AAO) nanopores with a high homogeneity of greater than 95%, using ultrasonication. The monomeric metal NP array exhibits asymmetric plasmonic absorption due to Fano‐like resonance as interpreted by finite‐difference time‐domain (FDTD) simulation for the numbers up to 127 AuNPs. To examine gap distance‐dependent collective‐plasmonic resonance, the different dimensions of S, M, and L arrays of the AuNP diameters/the gap distances of ≈36 nm/≈66 nm, ≈45 nm/≈56 nm, and ≈77 nm/≈12 nm, respectively, are prepared. Metal NP arrays with an invariable nanogap of ≈50 nm can provide consistent surface‐enhanced Raman scattering (SERS) intensities for Rhodamine 6G (Rh6G) with a relative standard deviation (RSD) of 3.8–5.4%. Monomeric arrays can provide an effective platform for 2D hot‐electron excitation, as evidenced by the SERS peak‐changes of 4‐nitrobenzenethiol (4‐NBT) adsorbed on AgNP arrays with a power density of ≈0.25 mW µm‐2 at 514 and 633 nm. For practical purposes, the bacteria captured by 4‐mercaptophenylboronic acid are found to be easily destroyed under visible laser excitation at 514 nm with a power density of ≈14 mW µm‐2 for 60 min using Ag due to efficient plasmonic‐electron transfer. 相似文献
5.
Tianru Wu Guqiao Ding Honglie Shen Haomin Wang Lei Sun Da Jiang Xiaoming Xie Mianheng Jiang 《Advanced functional materials》2013,23(2):198-203
A simple but efficient strategy to synthesize millimeter‐sized graphene single crystal grains by regulating the supply of reactants in the chemical vapor deposition (CVD) process is demonstrated. Polystyrene is used as a carbon source. Pulse heating on the carbon source is utilized to minimize the nucleation density of graphene on copper foil, while a gradual increase in the temperature of the carbon source and the flow rate of hydrogen is adapted to drive the continuous growth of the graphene grains. As a result, the nucleation density of graphene grain can be controlled to as low as ≈100 nuclei/cm2, and a single crystal grain can grow up to dimensions of ≈1.2 mm. Raman spectroscopy, transmission electron microscopy (TEM), and electrical‐transport measurements show that the graphene grains obtained are of high quality. The strategy presented provides very good controllability and enables the possibility of large graphene single crystals, which is of vital importance for practical applications. 相似文献
6.
Tianjing Wu Mingjun Jing Ye Tian Li Yang Jiugang Hu Xiaoyu Cao Guoqiang Zou Hongshuai Hou Xiaobo Ji 《Advanced functional materials》2019,29(17)
Heteroatom modification represents one of the major areas of carbon materials' research in electrical energy storage. However, the influence of heteroatomic state evolution on electrochemical properties remains an elusive topic. Herein, thiophene‐2,5‐dicarboxylic acid is chemically activated to prepare O,S‐diatomic hybrid carbon material (OS–C). The heteroatoms and carbon matrix coexist in the form of C?O/C? O and C? S/S? S bonds, which introduce porous networks to the partially graphitized carbon skeleton and provide abundant active sites for better ion absorption. Moreover, the heteroatoms and carbon matrix are bridged to establish stable pseudocapacitive functional groups like quinoid unit and disulfide bonds, which can be electrochemically converted into benzenoid units and mercaptan anions through Faradaic reactions to further improve the reversible capacity. Combined with the detailed kinetic exploration and in situ investigation of the electrochemical impedance spectra, the energy storage mechanism for lithium/sodium is proposed in the following steps: Faradaic reactions at a higher potential range, energy storage at active sites, and ions intercalation on the graphitized parts in the low‐voltage states. Greatly, the electrode can store lithium up to the capacity of ≈700 mAh g?1, while also delivering ≈330 mAh g?1 of sodium storage, providing lifetimes in excess of thousands of cycles. 相似文献
7.
Nitrogen‐Doped Nanoporous Carbon/Graphene Nano‐Sandwiches: Synthesis and Application for Efficient Oxygen Reduction
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Jing Wei Yaoxin Hu Yan Liang Biao Kong Jin Zhang Jingchao Song Qiaoliang Bao George P. Simon San Ping Jiang Huanting Wang 《Advanced functional materials》2015,25(36):5768-5777
A zeolitic‐imidazolate‐framework (ZIF) nanocrystal layer‐protected carbonization route is developed to prepare N‐doped nanoporous carbon/graphene nano‐sandwiches. The ZIF/graphene oxide/ZIF sandwich‐like structure with ultrasmall ZIF nanocrystals (i.e., ≈20 nm) fully covering the graphene oxide (GO) is prepared via a homogenous nucleation followed by a uniform deposition and confined growth process. The uniform coating of ZIF nanocrystals on the GO layer can effectively inhibit the agglomeration of GO during high‐temperature treatment (800 °C). After carbonization and acid etching, N‐doped nanoporous carbon/graphene nanosheets are formed, with a high specific surface area (1170 m2 g?1). These N‐doped nanoporous carbon/graphene nanosheets are used as the nonprecious metal electrocatalysts for oxygen reduction and exhibit a high onset potential (0.92 V vs reversible hydrogen electrode; RHE) and a large limiting current density (5.2 mA cm?2 at 0.60 V). To further increase the oxygen reduction performance, nanoporous Co‐Nx/carbon nanosheets are also prepared by using cobalt nitrate and zinc nitrate as cometal sources, which reveal higher onset potential (0.96 V) than both commercial Pt/C (0.94 V) and N‐doped nanoporous carbon/graphene nanosheets. Such nanoporous Co‐Nx/carbon nanosheets also exhibit good performance such as high activity, stability, and methanol tolerance in acidic media. 相似文献
8.
Brenda Long Mary Manning Micheal Burke Bartholomaeus N. Szafranek Giuseppe Visimberga Damien Thompson James C. Greer Ian M. Povey John MacHale Guaylord Lejosne Daniel Neumaier Aidan J. Quinn 《Advanced functional materials》2012,22(4):717-725
A simple, versatile method for non‐covalent functionalization of graphene based on solution‐phase assembly of alkane‐amine layers is presented. Second‐order Møller–Plesset (MP2) perturbation theory on a cluster model (methylamine on pyrene) yields a binding energy of ≈220 meV for the amine–graphene interaction, which is strong enough to enable formation of a stable aminodecane layer at room temperature. Atomistic molecular dynamics simulations on an assembly of 1‐aminodecane molecules indicate that a self‐assembled monolayer can form, with the alkane chains oriented perpendicular to the graphene basal plane. The calculated monolayer height (≈1.7 nm) is in good agreement with atomic force microscopy data acquired for graphene functionalized with 1‐aminodecane, which yield a continuous layer with mean thickness ≈1.7 nm, albeit with some island defects. Raman data also confirm that self‐assembly of alkane‐amines is a non‐covalent process, i.e., it does not perturb the sp2 hybridization of the graphene. Passivation and adsorbate n‐doping of graphene field‐effect devices using 1‐aminodecane, as well as high‐density binding of plasmonic metal nanoparticles and seeded atomic layer deposition of inorganic dielectrics using 1,10‐diaminodecane are also reported. 相似文献
9.
All‐Carbon Nanoarchitectures as High‐Performance Separation Membranes with Superior Stability
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Kunli Goh Wenchao Jiang Huseyin Enis Karahan Shengli Zhai Li Wei Dingshan Yu Anthony G. Fane Rong Wang Yuan Chen 《Advanced functional materials》2015,25(47):7348-7359
The application of graphene‐based membranes is hindered by their poor stability under practical hydrodynamic conditions. Here, nanocarbon architectures are designed by intercalating surface‐functionalized, small‐diameter, multi‐walled carbon nanotubes (MWCNTs) into reduced graphene oxide (rGO) sheets to create highly stable membranes with improved water permeability and enhanced membrane selectivity. With the intercalation of 10 nm diameter MWCNTs, the water permeability reaches 52.7 L m?2 h?1 bar?1, which is 4.8 times that of pristine rGO membrane and five to ten times higher than most commercial nanofiltration membranes. The membrane also attains almost 100% rejection for three organic dyes of different charges. More importantly, the membrane can endure a turbulent hydrodynamic flow with cross‐flow rates up to 2000 mL min?1 and a Reynolds number of 4667. Physicochemical characterization reveals that the inner graphitic walls of the MWCNTs can serve as spacers, while nanoscale rGO foliates on the outer walls interconnect with the assimilated rGO sheets to instill superior membrane stability. In contrast, intercalating with single‐walled nanotubes fails to reproduce such stability. Overall, this nanoarchitectured design is highly versatile in creating both graphene‐rich and CNT‐rich all‐carbon membranes with engineered nanochannels, and is regarded as a general approach in obtaining stable membranes for realizing practical applications of graphene‐based membranes. 相似文献
10.
Enhanced Electrocatalysis via 3D Graphene Aerogel Engineered with a Silver Nanowire Network for Ultrahigh‐Rate Zinc–Air Batteries
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Shang Hu Ting Han Chao Lin Weikai Xiang Yonghui Zhao Peng Gao Fuping Du Xiaopeng Li Yuhan Sun 《Advanced functional materials》2017,27(18)
3D graphene aerogel (GA) integrated with active metal or its derivatives has emerged as a novel class of multifunctional constructs with range of potential applications. However, GA fabricated by self‐assembly in the liquid phase still suffers from low conductivity and poor knowledge related to spatial active phase distribution and 3D structure. To address these issues, a facile approach involving in situ integration of 1D silver nanowire (AgNW) during gelation of graphene oxide flakes is presented. AgNWs prevent the restacking of graphene sheets and act as an efficient electron highway and Ag source for deposition of ultrasmall Ag nanocrystals (AgNCs). When applied as the cathodic electrocatalyst in a zinc–air battery, the 3D GA integrated with 0D AgNCs and 1D AgNWs permit ultrahigh discharge rates of up to 300 mA cm?2. Moreover, for the first time, with the help of phase‐contrast X‐ray computed microtomography, the interconnected porous network of millimeter‐sized GA and a full‐field view of the macrodistribution of Ag is delivered, offering the vitally complementary macroscopic structure information, which has been missing in previous reports. 相似文献
11.
Highly Efficient and Bendable Organic Solar Cells with Solution‐Processed Silver Nanowire Electrodes
Myungkwan Song Dae Sung You Kyounga Lim Sujin Park Sunghoon Jung Chang Su Kim Dong‐Ho Kim Do‐Geun Kim Jongk‐Kuk Kim Juyun Park Yong‐Cheol Kang Jinhee Heo Sung‐Ho Jin Jong Hyun Park Jae‐Wook Kang 《Advanced functional materials》2013,23(34):4177-4184
Highly efficient and bendable organic solar cells (OSCs) are fabricated using solution‐processed silver nanowire (Ag NW) electrodes. The Ag NW films were highly transparent (diffusive transmittance ≈ 95% at a wavelength of 550 nm), highly conductive (sheet resistance ≈ 10 Ω sq?1), and highly flexible (change in resistance ≈ 1.1 ± 1% at a bending radius of ≈200 μm). Power conversion efficiencies of ≈5.80 and 5.02% were obtained for devices fabricated on Ag NWs/glass and Ag NWs/poly(ethylene terephthalate) (PET), respectively. Moreover, the bendable devices fabricated using the Ag NWs/PET films decrease slightly in their efficiency (to ≈96% of the initial value) even after the devices had been bent 1000 times with a radius of ≈1.5 mm. 相似文献
12.
Highly Elastic and Conductive N‐Doped Monolithic Graphene Aerogels for Multifunctional Applications
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In Kyu Moon Seonno Yoon Kyoung‐Yong Chun Jungwoo Oh 《Advanced functional materials》2015,25(45):6976-6984
The simple synthesis of ultralow‐density (≈2.32 mg cm?3) 3D reduced graphene oxide (rGO) aerogels that exhibit high electrical conductivity and excellent compressibility are described herein. Aerogels are synthesized using a combined hydrothermal and thermal annealing method in which hexamethylenetetramine is employed as a reducer, nitrogen source, and graphene dispersion stabilizer. The N‐binding configurations of rGO aerogels increase dramatically, as evidenced by the change in pyridinic‐N/quaternary‐N ratio. The conductivity of this graphene aerogel is ≈11.74 S m?1 at zero strain, whereas the conductivity at a compressive strain of ≈80% is ≈704.23 S m?1, which is the largest electrical conductivity reported so far in any 3D sponge‐like low‐density carbon material. In addition, the aerogel has excellent hydrophobicity (with a water contact angle of 137.4°) as well as selective absorption for organic solvents and oils. The compressive modulus (94.5 kPa; ρ ≈ 2.32 mg cm?3) of the rGO aerogel is higher than that of other carbon‐based aerogels. The physical and chemical properties (such as high conductivity, elasticity, high surface area, open pore structure, and chemical stability) of the aerogel suggest that it is a viable candidate for the use in energy storage, electrodes for fuel cells, photocatalysis, environmental protection, energy absorption, and sensing applications. 相似文献
13.
Etching‐Free Epitaxial Growth of Gold on Silver Nanostructures for High Chemical Stability and Plasmonic Activity
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Hongpo Liu Tingzhuo Liu Lei Zhang Lu Han Chuanbo Gao Yadong Yin 《Advanced functional materials》2015,25(34):5435-5443
A robust method for epitaxial deposition of Au onto the surface of Ag nanostructures is demonstrated, which allows effective conversion of Ag nanostructures of various morphologies into Ag@Au counterparts, with the anisotropic ones showing excellent plasmonic properties comparable to the original Ag nanostructures while significantly enhanced stability. Sulfite plays a determining role in the success of this epitaxial deposition as it strongly complexes with gold cations to completely prevent galvanic replacement while it also remains benign to the Ag surface to avoid any ligand‐assisted oxidative etching. By using Ag nanoplates as an example, it is shown that the corresponding Ag@Au nanoplates possess remarkable plasmonic properties that are virtually Ag‐like, in clear contrast to Ag@Au nanospheres that exhibit much lower plasmonic activities than their Ag counterparts. As a result, they display high durability and activities in surface‐enhanced Raman scattering applications. This strategy may represent a general platform for depositing a noble metal on less stable metal nanostructures, thus opening up new opportunities in rational design of functional metal nanomaterials for a broad range of applications. 相似文献
14.
Agnieszka Stpniak‐Dybala Pawe Dyniec Marek Kopciuszyski Ryszard Zdyb Mieczysaw Jaochowski Mariusz Krawiec 《Advanced functional materials》2019,29(50)
2D sheets of graphene‐like silicon, namely planar silicene, are synthesized. This new silicon allotrope is prepared on Au(111) thin films grown on a Si(111) substrate in the process of surface segregation. Owing to its almost perfectly flat geometry it shares the atomic structure with graphene rather than with low‐buckled silicene. Scanning tunneling microscopy measurements clearly display an atomically resolved planar silicene honeycomb lattice. Ab initio density functional theory calculations fully support the experimental findings and predict a pure sp2 atomic configuration of Si atoms. The present work is the first experimental evidence of epitaxial planar silicene. 相似文献
15.
Neil W. Johnson Patrick Vogt Paola De Padova Israel Perez Ernst Z. Kurmaev Guy Le Lay Alexander Moewes 《Advanced functional materials》2014,24(33):5253-5259
Silicene is a two‐dimensional structure composed of a buckled hexagonal honeycomb lattice of silicon atoms. Freestanding silicene is yet to be synthesized, but epitaxial silicene monolayers have been directly observed or predicted to exist on a number of supporting substrates. Herein the atomic and electronic structures of five distinct epitaxial silicene morphologies on Ag(111) are examined through the complementary techniques of density functional theory and soft X‐ray spectroscopy at the Si L2,3 edge. Hybridization with the Ag(111) substrate is shown to cause these silicene monolayers to become strongly metallic, and the specific electronic interactions that are responsible for this metallic nature are determined. The results imply that epitaxial silicene on Ag(111) does not possess the Dirac cone electronic structure that is characteristic of freestanding silicene and graphene sheets. 相似文献
16.
Graphene as an Electron Shuttle for Silver Deoxidation: Removing a Key Barrier to Plasmonics and Metamaterials for SERS in the Visible
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Maria Losurdo Iris Bergmair Babak Dastmalchi Tong‐Ho Kim Maria M. Giangregroio Wenyuan Jiao Giuseppe V. Bianco April S. Brown Kurt Hingerl Giovanni Bruno 《Advanced functional materials》2014,24(13):1864-1878
The role of graphene in enabling deoxidation of silver nanostructures, thereby contributing to enhance plasmonic properties and to improve the temporal stability of graphene/silver hybrids for both general plasmonic and meta‐materials applications, as well as for surface enhanced Raman scattering (SERS) substrates, is demonstrated. The chemical mechanism occurring at the graphene–silver oxide interface is based on the reduction of silver oxide triggered by graphene that acts as a shuttle of electrons and as a kind of catalyst in the deoxidation. A mechanism is formulated, combining elements of electron transfer, role of defects in graphene, and electrochemical potentials of graphene, silver, and oxygen. Therefore, the formulated model represents a step forward from the simple view of graphene as barrier to oxygen diffusion proposed so far in literature. Single layer graphene grown by chemical vapor deposition is transferred onto silver thin films, a periodic silver fishnet structure fabricated by nanoimprint lithography, and onto silver nanoparticle ensembles supporting a localized surface plasmon resonance in the visible range. Through the study of these nanostructured graphene/Ag hybrids, the effectiveness of graphene in preventing and reducing oxidation of silver plasmonic structures, keeping silver in a metallic state over months at air exposure, is demonstrated. The enhanced and stable plasmonic properties of the silver‐fishnet/graphene hybrids are evaluated through their SERS response for detecting benzyl mercaptane. 相似文献
17.
Regulating Top‐Surface Multilayer/Single‐Crystal Graphene Growth by “Gettering” Carbon Diffusion at Backside of the Copper Foil
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Irfan H. Abidi Yuanyue Liu Jie Pan Abhishek Tyagi Minghao Zhuang Qicheng Zhang Aldrine A. Cagang Lu‐Tao Weng Ping Sheng William A. Goddard III Zhengtang Luo 《Advanced functional materials》2017,27(23)
A unique strategy is reported to constrain the nucleation centers for multilayer graphene (MLG) and, later, single‐crystal graphene domains by gettering carbon source on backside of the flat Cu foil, during chemical vapor deposition. Hitherto, for a flat Cu foil, the top‐surface‐based growth mechanism is emphasized, while overlooking the graphene on the backside. However, the systematic experimental findings indicate a strong correlation between the backside graphene and the nucleation centers on the top‐surface, governed by the carbon diffusion through the bulk Cu. This understanding steers to devise a strategy to mitigate the carbon diffusion to the top‐surface by using a carbon “getter” substrate, such as nickel, on the backside of the Cu foil. Depth profiling of the nickel substrate, along with the density functional theory calculations, verifies the gettering role of the nickel support. The implementation of the backside carbon gettering approach on single‐crystal graphene growth results in lowering the nucleation density by two orders of magnitude. This enables the single‐crystal domains to grow by 6 mm laterally on the untreated Cu foil. Finally, the growth of large‐area polycrystalline single layer graphene, free of unwanted MLG domains, with significantly improved field‐effect mobility of ≈6800 cm2 V?1 s?1 is demonstrated. 相似文献
18.
Javad Foroughi Geoffrey M. Spinks Dennis Antiohos Azadehsadat Mirabedini Sanjeev Gambhir Gordon G. Wallace Shaban R. Ghorbani Germanas Peleckis Mikhail E. Kozlov Marcio D. Lima Ray H. Baughman 《Advanced functional materials》2014,24(37):5859-5865
An efficient procedure for the fabrication of highly conductive carbon nanotube/graphene hybrid yarns has been developed. To start, arrays of vertically aligned multi‐walled carbon nanotubes (MWNT) are converted into indefinitely long MWNT sheets by drawing. Graphene flakes are then deposited onto the MWNT sheets by electrospinning to form a composite structure that is transformed into yarn filaments by twisting. The process is scalable for yarn fabrication on an industrial scale. Prepared materials are characterized by electron microscopy, electrical, mechanical, and electrochemical measurements. It is found that the electrical conductivity of the composite MWNT‐graphene yarns is over 900 S/cm. This value is 400% and 1250% higher than electrical conductivity of pristine MWNT yarns or graphene paper, respectively. The increase in conductivity is asssociated with the increase of the density of states near the Fermi level by a factor of 100 and a decrease in the hopping distance by an order of magnitude induced by grapene flakes. It is found also that the MWNT‐graphene yarn has a strong electrochemical response with specific capacitance in excess of 111 Fg?1. This value is 425% higher than the capacitance of pristine MWNT yarn. Such substantial improvements of key properties of the hybrid material can be associated with the synergy of MWNT and graphene layers in the yarn structure. Prepared hybrid yarns can benefit such applications as high‐performance supercapacitors, batteries, high current capable cables, and artificial muscles. 相似文献
19.
Yunzhao Wu Mingchao Wang Ye Tao Kai Zhang Molang Cai Yong Ding Xuepeng Liu Tasawar Hayat Ahmed Alsaedi Songyuan Dai 《Advanced functional materials》2020,30(5)
3D graphene, as a light substrate for active loadings, is essential to achieve high energy density for aqueous Zn‐ion batteries, yet traditional synthesis routes are inefficient with high energy consumption. Reported here is a simplified procedure to transform the raw graphite paper directly into the graphene‐like carbon film (GCF). The electrochemically derived GCF contains a 2D–3D hybrid network with interconnected graphene sheets, and offers a highly porous structure. To realize high energy density, the Na:MnO2/GCF cathode and Zn/GCF anode are fabricated by electrochemical deposition. The GCF‐based Zn‐ion batteries deliver a high initial discharge capacity of 381.8 mA h g?1 at 100 mA g?1 and a reversible capacity of 188.0 mA h g?1 after 1000 cycles at 1000 mA g?1. Moreover, a recorded energy density of 511.9 Wh kg?1 is obtained at a power density of 137 W kg?1. The electrochemical kinetics measurement reveals the high capacitive contribution of the GCF and a co‐insertion/desertion mechanism of H+ and Zn2+ ions. First‐principles calculations are also carried out to investigate the effect of Na+ doping on the electrochemical performance of layered δ‐MnO2 cathodes. The results demonstrate the attractive potential of the GCF substrate in the application of the rechargeable batteries. 相似文献
20.
Yongkwon Song Donghee Kim Sungkun Kang Younji Ko Jongkuk Ko June Huh Yongmin Ko Seung Woo Lee Jinhan Cho 《Advanced functional materials》2019,29(30)
To fabricate flexible electrodes, conventional silver (Ag) nanomaterials have been deposited onto flexible substrates, but the formed electrodes display limited electrical conductivity due to residual bulky organic ligands, and thus postsintering processes are required to improve the electrical conductivity. Herein, an entirely different approach is introduced to produce highly flexible electrodes with bulk metal–like electrical conductivity: the room‐temperature metallic fusion of multilayered silver nanoparticles (NPs). Synthesized tetraoctylammonium thiosulfate (TOAS)‐stabilized Ag NPs are deposited onto flexible substrates by layer‐by‐layer assembly involving a perfect ligand‐exchange reaction between bulky TOAS ligands and small tris(2‐aminoethyl)amine linkers. The introduced small linkers substantially reduce the separation distance between neighboring Ag NPs. This shortened interparticle distance, combined with the low cohesive energy of Ag NPs, strongly induces metallic fusion between the close‐packed Ag NPs at room temperature without additional treatments, resulting in a high electrical conductivity of ≈1.60 × 105 S cm?1 (bulk Ag: ≈6.30 × 105 S cm?1). Furthermore, depositing the TOAS–Ag NPs onto cellulose papers through this approach can convert the insulating substrates into highly flexible and conductive papers that can be used as 3D current collectors for energy‐storage devices. 相似文献