Naoki Komatsu
Abstract
Nanocarbons are carbon allotropes with nanometer scale and comprised mainly of 0 – 3 dimensional (0D – 3D) forms; fullerenes (0D), carbon nanotubes (1D), graphene (2D), and nanodiamond (3D). In our group, various surfactants with appropriate size and shape have been developed for the nanocarbons. ...
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Nanocarbons are carbon allotropes with nanometer scale and comprised mainly of 0 – 3 dimensional (0D – 3D) forms; fullerenes (0D), carbon nanotubes (1D), graphene (2D), and nanodiamond (3D). In our group, various surfactants with appropriate size and shape have been developed for the nanocarbons. In order to separate the fullerenes, bowl-shaped surfactants were designed and synthesized to accommodate the 0D spherical nanocarbon, giving C70 selectively as precipitates. On the other hand, gable- and bracket-shaped surfactants formed stable complexes with 1D tubular nanocarbons, dispersing carbon nanotubes with specific diameter, handedness and/or metallicity selectively in solution phase. The flat surfactants worked as an exfoliant and dispersant for graphite in both wet and dry processes; sonication and ball milling, respectively. They gave graphene composites with high concentrations and yield in aqueous solution and low-boiling point organic solvents. The hyper-branched polymer named polyglycerol coated the nanodiamond surface covalently through ring-opening polymerization of glycidol. The chemisorped polymer gave large hydrophilicity to the nanodiamond, dispersing it stably in aqueous solutions such as water and phosphate buffer as well as polar organic solvents such as methanol. Copyright © VBRI Press.
Arenst Andreas Arie; Joong Kee Lee
Abstract
In this work, LiCoO2(LCO) composite electrodes were coated by fullerene C60 thin film with different thickness of 60, 100 and 200 nm using a plasma thermal evaporation technique. The surface morphology of bare and coated samples was observed by scanning electron microscope (SEM). The electrochemical ...
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In this work, LiCoO2(LCO) composite electrodes were coated by fullerene C60 thin film with different thickness of 60, 100 and 200 nm using a plasma thermal evaporation technique. The surface morphology of bare and coated samples was observed by scanning electron microscope (SEM). The electrochemical characteristics of the coated electrodes as cathode materials in Lithium-Ion Batteries (LIB)were investigated by a galvanostatic charge-discharge test at various C-rates between 3.0 and 4.5 V and compared with those of uncoated samples. An improvement of the performances of the coated electrodes in terms of higher initial coulombic efficiency, higher capacity retention and better rate capability was shown by the 60 nm thick C60 coated LiCoO2 electrodes. It can be said that the thin C60 coating layer can minimize the dissolution of Co from the electrode to the electrolyte. As the thickness of coating layer was increased, the coated electrodes show a more severe capacity fade due to longer Li-ion diffusion path.
R. Singhal; A. Tripathi; D. K. Avasthi
Abstract
Electrically conducting carbon nanowires, all parallel to each other and embedded in fullerene C70 matrix are created by swift heavy ion irradiation of thin fullerene C70 film at low fluences (up to 10 10 ions/cm 2 ). The conductivity of the wires is several orders of magnitude higher than the surrounding ...
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Electrically conducting carbon nanowires, all parallel to each other and embedded in fullerene C70 matrix are created by swift heavy ion irradiation of thin fullerene C70 film at low fluences (up to 10 10 ions/cm 2 ). The conductivity of the wires is several orders of magnitude higher than the surrounding material and it is due to the transformation of fullerene into amorphous carbon within each ion hit zone. These conducting nanowires are evidenced by conducting atomic force microscopy. The typical diameter of the conducting tracks is observed to be about 11-21 nm.
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