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In this study, nanocomposite films of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF–HFP) incorporating polyethylenimine (PEI)-covalently modified graphene sheets (rGO–PEI) were prepared by a solution-cast method, and the dielectric properties of the films were studied. Infrared spectroscopy, atom force microscope, X-ray photoelectron spectroscopy, solid state NMR spectroscopy, Raman, thermogravimetry...
Up to now, the cost-effective mass production of pristine graphene sheets remains a significant challenge. We report a binary solvent system of dimethylformamide and n-butylalcohol that facilitates the high concentration production of unoxidized graphene through liquid-exfoliation assisted with sonication. A stable dispersion with concentration as high as 6.5mg/ml, was received via this method. The...
Boron-catalyzed graphitization of carbon fibers was conducted in a boron-doped graphite crucible at 2000°C, in which boron diffused from the crucible to the carbon fibers to act as the catalyst. The microstructures, boron contents and mechanical properties of the resulting carbon fibers were characterized by Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, high-resolution...
S-doped carbon nanotubes (SCNTs) obtained by a post treatment approach are used as conductive additive for LiFePO4 (LFP) cathodes in Lithium ion batteries (LIBs). The SCNTs exhibit higher specific surface area, higher conductivity and better hydrophily as compared to the pristine CNTs because of S doping. Thus the SCNTs can be stably dispersed in water, forming an aqueous conductive slurry. The LFP...
We investigate dynamic fracture of C/SiC composites under high strain-rate compression or tension with split Hopkinson pressure bar (SHPB) and gas gun loading. Components of the as-fabricated composites are mapped and quantified with X-ray computed tomography, including C fibers and fiber bundles, SiC matrix, and inter- and intrabundle voids. Compression loading is applied along the out-of- and in-plane...
As an alternative to potentially carcinogenic hydrazine for fuel cell application, carbohydrazide, which contains lone electron pairs on nitrogen atoms and readily activated N–H bonds, can be catalytically oxidized over metal-free carbon catalysts due to the high equilibrium electromotive force (1.65V) of its oxidation reaction. Carbon nanotubes are found to electrochemically catalyze the carbohydrazide...
The feasibility of using thermally reduced graphene oxide (TrGO) to improve the antioxidative efficiency of commercial antioxidant (3,5-di-tert-butyl-4-hydroxycinnamic acid, AO) on unstabilized polypropylene (PP) was evaluated in terms of the oxidation induction time (OIT) and the initial degradation temperature (Ti). It was found that a synergistic effect exist between AO and TrGO in retarding the...
The design and preparation of high comprehensive performance composite phase change materials (PCMs) via a straightforward route were pioneered. Graphene oxide (GO) nanosheets were introduced as supporting materials to keep the shape of polyethylene glycol (PEG) stable during the phase change process and graphene nanoplatelets (GNP) were used as conductive fillers to improve the thermal conductivity...
Infiltration of molten FLiNaK salt into degassed nuclear graphite samples under inert gas pressure was studied. The weight gain of different grades (2020, 2114, IG-110, NBG-8, G1 and G2) of nuclear graphite during infiltration with different pressures was measured. Molten salt infiltration was compared with mercury intrusion porosimetry where it was found that mercury infiltration was a useful predictor...
A novel three-dimensional (3D) nanoarchitecture consisting of hybrid graphene nanosheets (GNs)/graphene foam (GF) was fabricated on the FTO conducting substrate as a high efficient counter electrode (CE) for dye sensitized solar cells (DSSCs). The GNs with various sized such as large-sized heat-reduced graphene nanosheets (H-GNs) and small-sized laser-reduced graphene quantum dots (L-GQDs) were synthesized...
The microstructures of amorphous solid-core carbon nanofibers (CNFs) synthesized in flames show long-range disorder, which makes it difficult to reconstruct their three-dimensional atom configurations by popular characterization methods.Using a reverse Monte Carlo method, the atom configurations of CNFs were derived from X-ray diffraction data, and these were used to calculate the Fermi levels, density...
A series of carbon fiber (CF)/polyether polyurethane (PU) composites were prepared by in situ polymerization and a casting compression molding technique. The influence of CF content and its pretreatment with a coupling agent and oxidation by 65%-68% (mass fraction) nitric acid on the mechanical performance, thermal properties and morphology of the composites was investigated by TGA, SEM and mechanical...
Electrically conductive polycarbonate (PC)/carbon nanotube (CNT) composites were prepared by melt compounding. Well-controlled voids were introduced into the PC/CNT composites by supercritical CO2 foaming technique. The dispersion of CNTs and the cellular morphology of the PC composite foams were characterized with transmission electron microscopy and scanning electron microscopy, respectively. The...
An efficient surface enhanced Raman scattering (SERS) substrate has been developed based on Ag nanoparticle-decorated graphene oxide (GO). The structure of Ag@GO hybrid material was confirmed by X-ray diffraction, transmission and scanning electron microscopy. The as-prepared substrate exhibited the enhancement ability of SERS toward various aromatic dyes, such as Rhodamine 6G, Rhodamine B, and crystal...
Lithium-ion batteries (LIBs) are extensively used in numerous portable devices such as smart-phones and laptops. However, current LIBs based on the conventional intercalation mechanism cannot meet the requirements of the electronics industry and electric vehicles although they are approaching their theoretical capacity. Therefore, it is extremely urgent to seek for systems with higher energy densities...
Epitaxial graphene is grown on a non-polar n+ 6H-SiC m-plane substrate and studied using atomic scale scanning tunneling microscopy. Multilayer graphene is found throughout the surface and exhibits rotational disorder. Moiré patterns of different spatial periodicities are found, and we found that as the wavelength increases, so does the amplitude of the modulations. This relationship reveals information...
A novel pyridine-containing metal-organic framework (MOF), [Zn(bpdc)DMA]·DMF, was first constructed by solvothermal reaction of 2,2′-bipyridine-5,5′-dicarboxylate (bpdc) with zinc nitrate, and then it was converted to nitrogen-doped porous carbons (NPCs) by direct carbonization. The as-prepared porous carbon (NPC800) was characterized by scanning electron microscopy (SEM), X-ray powder diffraction...
Improving the interaction of graphene with terahertz (THz) waves in experiment – through experimental measurement is a challenge for THz detectors, modulators, and other THz photonic components based on graphene. Hybridization of graphene with metamaterials leads to a strong THz response enhancement. Here, we observed maximum enhancement of 33.0% in non-resonant region and 23.8% in resonant region...
Hierarchically porous carbon materials have many important technological applications; however, most of them were fabricated using either expensive materials or complicated procedures. Based on a general chelate-assisted multi-component co-assembly strategy, nitrogen-doped hierarchically porous carbon materials were fabricated by using Al-based composite and commercial triblock copolymer Pluronic...
The rational integration of conductive nanocarbon scaffolds and insulative sulfur is an efficient method to build composite cathodes for high-energy-density lithium–sulfur batteries. The full demonstration of the high-energy-density electrodes is a key issue towards full utilization of sulfur in a lithium–sulfur cell. Herein, carbon nanotubes (CNTs) that possess robust mechanical properties, excellent...
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