A transmission electron microscope and electron diffraction study of carbon nanodisks

Garberg, Torgunn; Naess, Stine Nalum; Helgesen, Geir; Knudsen, Kenneth D.; Kopstad, G.; Elgsaeter, Arnljot

doi:10.1016/j.carbon.2008.06.044

Cited by 29 publications

(31 citation statements)

References 9 publications

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“…Using different images, we calculate the average spacing as 3.76 ± 0.10 Å, thus a layer distance which is significantly larger than in graphite. This observation is consistent with what we found earlier for carbon nanodiscs [25].…”

Section: Resultssupporting

confidence: 83%

“…By carefully drawing lines separating the facets in several different carbon cones, and making use of the relations described above, we find that for all cones, the facet interfacial angles of a pair of facets, φ . These values are the same as those found earlier for carbon nanodiscs [25], and correspond to Miller indices (100) and (210) of the two-dimensional hexagonal unit cell in graphite. As demonstrated by Eksioglu and Nadarajah [27], and also pointed out earlier [28], an alternating shift by ±21.8…”

Section: Resultssupporting

confidence: 63%

“…The electron beam attenuation factor, i.e. the average Beer-Lambert-Bouguer attenuation factor K for the 100 keV beam used was K = 0.0090 nm −1 as can be calculated from the measurements of Garberg et al [25] for disc-shaped particles at an electron beam energy of 80 kV using the appropriate energy and aperture corrections [26]. Figure 2(b) shows a comparison between the experimentally determined relative transmitted electron beam intensity, I (x)/I 0 , and that calculated theoretically, along a line defined by a vertical plane located at different distances from the apex of the cone in figure 2(a).…”

Section: Resultsmentioning

confidence: 99%

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Carbon nanocones: wall structure and morphology

Naess

Elgsaeter

Helgesen

et al. 2009

Science and Technology of Advanced Materials

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Large-scale production of conical carbon nanostructures is possible through pyrolysis of hydrocarbons in a plasma torch process. The resulting carbon cones occur in five distinctly different forms, and disc-shaped particles are produced as well. The structure and properties of these carbon cones and discs have been relatively little explored until now. Here we characterize the structure of these particles using transmission electron microscopy, synchrotron x-ray and electron diffraction. The carbon nanocones are found to exhibit several interesting structural features; instead of having a uniform cross-section, the walls consist of a relatively thin inner graphite-like layer with a non-crystalline envelope, where the amount of the latter can be modified significantly by annealing. The cones appear with a well-defined faceting along the cone edge, demonstrating strict long-range atomic ordering; they also present occasional examples of symmetry breaking, such as two apexes appearing in the same carbon nanocone.

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Section: Resultssupporting

confidence: 83%

Section: Resultssupporting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

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Carbon nanocones: wall structure and morphology

Naess

Elgsaeter

Helgesen

et al. 2009

Science and Technology of Advanced Materials

Self Cite

123

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“…The carbon cone based material is a mixture of hollow cones and flat disks of carbon. The as-produced material consists of a crystalline core with a disordered outer shell [42], while CC2700 is graphitized, i.e. SEM and XRD shows that heat treatment makes the material more crystalline.…”

Section: Thermal Conductivity Measurementsmentioning

confidence: 99%

Thermal Conductivity, Heat Sources and Temperature Profiles of Li-Ion Batteries

et al. 2014

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In this paper we report the thermal conductivity of several commercial and noncommercial Li-ion secondary battery electrode materials with and without electrolyte solvents. We also measure the Tafel potential, the ohmic resistance, reaction entropy and external temperature of a commercial pouch cell secondary Li-ion battery. Finally we combined all the experimentally obtained data in a thermal model and discuss the corresponding internal temperature effects.The thermal conductivity of dry electrode material was found to range from 0.07 to 0.41 W K −1 m −1 while the electrode material soaked in electrolyte solvent ranged from 0.36 to 1.10 W K −1 m −1 . For all the different materials it was found that adding the electrolyte solvent increased the thermal conductivity by at least a factor of three. For one of the anode materials it was found that heat treatment at 3000 K increased the thermal conductivity by a factor of almost five.Measuring the electric heat sources of an air cooled commercial pouch cell battery at up to ± 2C and the thermal conductivity of the electrode components made it possible to estimate internal temperature profiles. Combining the heat sources with tabulated convective heat transfer coefficients of air allowed us to calculate the ambient temperature profiles. At 12C charging rate (corresponding to 5 minutes complete charging) the internal temperature differences was estimated to be in the range of 4-20K, depending on the electrode thermal conductivity. The external temperature drop in air flowing at the battery surface was estimated to nearly 40K. Evaluating thermal * Corresponding author; odnesb@hist.no management of batteries in the light of our measurement led to the conclusion that external cooling is more challenging than internal, though neither should be neglected.

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“…Transmission electron microscope and electron diffraction studies reveal that these disks have multi-layered, graphitic structures [5]. In this study we focus on the characterization of the carbon nanodisks by atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and confocal Raman spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Substrate-induced strain in carbon nanodisks

et al. 2014

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Abstract:Graphitic nanodisks of typically 20 -50 nm in thickness, produced by the so-called Kvaerner Carbon Black and Hydrogen Process were dispersed on gold substrate and investigated by atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and confocal Raman spectroscopy. The roughness of the gold surface was drastically changed by annealing at 400 o C. AFM measurements show that this change in the surface roughness induces changes also in the topography of the nanodisks, as they closely follow the corrugation of the gold substrate. This leads to strained nanodisks, which is confirmed also by confocal Raman microscopy. We found that the FE-SEM contrast obtained from the disks depends on the working distance used during the image acquisition by In-lens detection, a phenomenon which we explain by the decrease in the amount of electrons reaching the detector due to diffraction. This process may affect the image contrast in the case of other layered materials, like hexagonal boron nitride, and other planar hybrid nanostructures, too.

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A transmission electron microscope and electron diffraction study of carbon nanodisks

Cited by 29 publications

References 9 publications

Carbon nanocones: wall structure and morphology

Carbon nanocones: wall structure and morphology

Thermal Conductivity, Heat Sources and Temperature Profiles of Li-Ion Batteries

Substrate-induced strain in carbon nanodisks

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