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Hirokazu Aoyama - One of the best experts on this subject based on the ideXlab platform.

  • Thermal and oxidation stability of organo-Fluorine compound-mixed electrolyte solutions for lithium ion batteries
    Journal of Power Sources, 2013
    Co-Authors: Daiki Nishikawa, Tsuyoshi Nakajima, Yoshimi Ohzawa, Akiyoshi Yamauchi, Michiru Kagawa, Hirokazu Aoyama
    Abstract:

    Abstract Thermal and oxidation stability of Fluorine compound-mixed electrolyte solutions have been investigated. Charge/discharge behavior of natural graphite electrode has been also examined in the same electrolyte solutions. Fluorine Compounds demonstrate much lower reactivity with metallic Li than ethylene carbonate/dimethyl carbonate. Fluorine compound-mixed electrolyte solutions show the lower reactivity with LiC6 and the smaller exothermic peaks due to decomposition of electrolyte solutions and surface films than original solutions without Fluorine compound. Oxidation currents are also smaller in Fluorine compound-mixed electrolyte solutions than in original ones. First coulombic efficiencies in Fluorine compound-mixed electrolyte solutions are similar to those in original ethylene carbonate-based solutions except one case. Mixing of Fluorine Compounds highly increase first coulombic efficiencies of natural graphite electrode in propylene carbonate-containing solution.

  • safety improvement of lithium ion batteries by organo Fluorine Compounds
    Journal of Fluorine Chemistry, 2011
    Co-Authors: Yuki Matsuda, Tsuyoshi Nakajima, Yoshimi Ohzawa, Akiyoshi Yamauchi, Michiru Kagawa, Hirokazu Aoyama
    Abstract:

    Abstract Thermal stability, electrochemical oxidation stability and charge/discharge characteristics of natural graphite powder were investigated by mixing of five fluoro-carbonates with 1 mol/L LiClO 4 –EC/DEC/PC (1:1:1 vol.). DSC study revealed that thermal stability of the electrolyte solution was improved by mixing of fluoro-carbonates by 10.0–33.3 vol.%. Electrochemical oxidation stability was also improved. Oxidation currents for Pt electrode significantly decreased by mixing of fluoro-carbonates. In the fluoro-carbonate-mixed electrolyte solutions, electrochemical reduction of PC decreased with increasing concentration of fluoro-carbonate and current density. As a result, first coulombic efficiency for natural graphite electrode increased, that is, irreversible capacity decreased in the fluoro-carbonate-mixed solutions.

  • thermal stability and electrochemical properties of Fluorine Compounds as nonflammable solvents for lithium ion batteries
    Journal of The Electrochemical Society, 2010
    Co-Authors: Takashi Achiha, Tsuyoshi Nakajima, Yoshimi Ohzawa, Akiyoshi Yamauchi, Michiru Kagawa, Hirokazu Aoyama
    Abstract:

    Differential scanning calorimetry study demonstrated that mixing of fluoro-ethers and fluoro-carbonates improved the thermal stability of 0.67 mol/L LiClO 4 ―ethylene carbonate (EC)/diethyl carbonate (DEC)/propylene carbonate (PC) (1:1:1 by volume). The oxidation currents were smaller in the Fluorine compound-mixed electrolyte solutions than in 0.67 mol/L LiClO 4 ―EC/DEC/PC, which also shows a high stability of the Fluorine compound-mixed electrolyte solutions against electrochemical oxidation. Electrochemical reduction of Fluorine Compounds took place at the higher potentials than EC, DEC, and PC, as suggested by the highest occupied molecular orbital and lowest unoccupied p-molecular orbital energies of the Fluorine Compounds. However, charge/discharge experiments using natural graphite (NG) electrodes showed that the Fluorine Compounds increased first coulombic efficiencies due to the quick formation of the solid electrolyte interphase on NG in PC-containing solvents.

  • electrochemical behavior of nonflammable organo Fluorine Compounds for lithium ion batteries
    Journal of The Electrochemical Society, 2009
    Co-Authors: Takashi Achiha, Tsuyoshi Nakajima, Yoshimi Ohzawa, Akiyoshi Yamauchi, Michiru Kagawa, Hirokazu Aoyama
    Abstract:

    The electrochemical behavior of organo-Fluorine Compounds with antioxidation ability has been investigated. Oxidation currents of Fluorine-compound-containing ethylene carbonate (EC)/diethyl carbonate (DEC) solutions were much smaller than those of EC/ DEC and EC/DEC/propylene carbonate (PC) at potentials higher than 6 V vs Li/Li + . Electrochemical reduction of Fluorine Compounds started at ca. 2 V vs Li/Li + , higher than those for EC, DEC, and PC. However the first coulombic efficiencies for natural graphite electrodes in Fluorine-compound-containing EC/DEC mixtures were nearly the same as those in EC/DEC without an increase in irreversible capacities. Furthermore the first coulombic efficiencies in Fluorine-compound-containing EC/DEC/PC mixtures were much larger than those in EC/DEC/PC itself. The results show that the Fluorine Compounds used in the present study can be used as nonflammable solvents for lithium ion batteries.

Tsuyoshi Nakajima - One of the best experts on this subject based on the ideXlab platform.

  • Thermal and oxidation stability of organo-Fluorine compound-mixed electrolyte solutions for lithium ion batteries
    Journal of Power Sources, 2013
    Co-Authors: Daiki Nishikawa, Tsuyoshi Nakajima, Yoshimi Ohzawa, Akiyoshi Yamauchi, Michiru Kagawa, Hirokazu Aoyama
    Abstract:

    Abstract Thermal and oxidation stability of Fluorine compound-mixed electrolyte solutions have been investigated. Charge/discharge behavior of natural graphite electrode has been also examined in the same electrolyte solutions. Fluorine Compounds demonstrate much lower reactivity with metallic Li than ethylene carbonate/dimethyl carbonate. Fluorine compound-mixed electrolyte solutions show the lower reactivity with LiC6 and the smaller exothermic peaks due to decomposition of electrolyte solutions and surface films than original solutions without Fluorine compound. Oxidation currents are also smaller in Fluorine compound-mixed electrolyte solutions than in original ones. First coulombic efficiencies in Fluorine compound-mixed electrolyte solutions are similar to those in original ethylene carbonate-based solutions except one case. Mixing of Fluorine Compounds highly increase first coulombic efficiencies of natural graphite electrode in propylene carbonate-containing solution.

  • Fluorine Compounds as energy conversion materials
    Journal of Fluorine Chemistry, 2013
    Co-Authors: Tsuyoshi Nakajima
    Abstract:

    Abstract Fluorine Compounds are quite useful as energy conversion materials, in particular as primary and secondary lithium battery materials. Primary lithium battery with graphite fluoride cathode was commercialized in 1973, based on the research on graphite fluoride. Since then, it has been shown that Fluorine Compounds are useful and attractive materials for lithium batteries. The present account paper reports the historical aspects and update topics on Fluorine Compounds such as graphite fluorides, Fluorine–graphite intercalation Compounds and organo-Fluorine Compounds as energy conversion materials. Surface modification by Fluorine is also reported.

  • safety improvement of lithium ion batteries by organo Fluorine Compounds
    Journal of Fluorine Chemistry, 2011
    Co-Authors: Yuki Matsuda, Tsuyoshi Nakajima, Yoshimi Ohzawa, Akiyoshi Yamauchi, Michiru Kagawa, Hirokazu Aoyama
    Abstract:

    Abstract Thermal stability, electrochemical oxidation stability and charge/discharge characteristics of natural graphite powder were investigated by mixing of five fluoro-carbonates with 1 mol/L LiClO 4 –EC/DEC/PC (1:1:1 vol.). DSC study revealed that thermal stability of the electrolyte solution was improved by mixing of fluoro-carbonates by 10.0–33.3 vol.%. Electrochemical oxidation stability was also improved. Oxidation currents for Pt electrode significantly decreased by mixing of fluoro-carbonates. In the fluoro-carbonate-mixed electrolyte solutions, electrochemical reduction of PC decreased with increasing concentration of fluoro-carbonate and current density. As a result, first coulombic efficiency for natural graphite electrode increased, that is, irreversible capacity decreased in the fluoro-carbonate-mixed solutions.

  • thermal stability and electrochemical properties of Fluorine Compounds as nonflammable solvents for lithium ion batteries
    Journal of The Electrochemical Society, 2010
    Co-Authors: Takashi Achiha, Tsuyoshi Nakajima, Yoshimi Ohzawa, Akiyoshi Yamauchi, Michiru Kagawa, Hirokazu Aoyama
    Abstract:

    Differential scanning calorimetry study demonstrated that mixing of fluoro-ethers and fluoro-carbonates improved the thermal stability of 0.67 mol/L LiClO 4 ―ethylene carbonate (EC)/diethyl carbonate (DEC)/propylene carbonate (PC) (1:1:1 by volume). The oxidation currents were smaller in the Fluorine compound-mixed electrolyte solutions than in 0.67 mol/L LiClO 4 ―EC/DEC/PC, which also shows a high stability of the Fluorine compound-mixed electrolyte solutions against electrochemical oxidation. Electrochemical reduction of Fluorine Compounds took place at the higher potentials than EC, DEC, and PC, as suggested by the highest occupied molecular orbital and lowest unoccupied p-molecular orbital energies of the Fluorine Compounds. However, charge/discharge experiments using natural graphite (NG) electrodes showed that the Fluorine Compounds increased first coulombic efficiencies due to the quick formation of the solid electrolyte interphase on NG in PC-containing solvents.

  • electrochemical behavior of nonflammable organo Fluorine Compounds for lithium ion batteries
    Journal of The Electrochemical Society, 2009
    Co-Authors: Takashi Achiha, Tsuyoshi Nakajima, Yoshimi Ohzawa, Akiyoshi Yamauchi, Michiru Kagawa, Hirokazu Aoyama
    Abstract:

    The electrochemical behavior of organo-Fluorine Compounds with antioxidation ability has been investigated. Oxidation currents of Fluorine-compound-containing ethylene carbonate (EC)/diethyl carbonate (DEC) solutions were much smaller than those of EC/ DEC and EC/DEC/propylene carbonate (PC) at potentials higher than 6 V vs Li/Li + . Electrochemical reduction of Fluorine Compounds started at ca. 2 V vs Li/Li + , higher than those for EC, DEC, and PC. However the first coulombic efficiencies for natural graphite electrodes in Fluorine-compound-containing EC/DEC mixtures were nearly the same as those in EC/DEC without an increase in irreversible capacities. Furthermore the first coulombic efficiencies in Fluorine-compound-containing EC/DEC/PC mixtures were much larger than those in EC/DEC/PC itself. The results show that the Fluorine Compounds used in the present study can be used as nonflammable solvents for lithium ion batteries.

Ganpat Mani - One of the best experts on this subject based on the ideXlab platform.

  • Kirk‐Othmer Encyclopedia of Chemical Technology - Fluorine Compounds, Inorganic, Sulfur
    Kirk-Othmer Encyclopedia of Chemical Technology, 2000
    Co-Authors: Francis E. Evans, Ganpat Mani
    Abstract:

    The two most commercially important sulfur-containing inorganic Fluorine Compounds are fluorosulfuric acid and sulfur hexafluoride. Fluorosulfuric acid is used as a fluorinating reagent in the preparation of such Compounds as boron trifluoride and silicon tetrafluoride, and as a catalyst in organic reactions for alkylation, acylation, polymerization, sulfonation, and isomerization. Fluorosulfuric acid is itself a strong acid. When combined with certain inorganic fluorides, the system exhibits superacid properties. Properties, manufacture, and uses are discussed. Of the known sulfur fluorides, sulfur hexafluoride and sulfur tetrafluoride are available commercially. Sulfur hexafluoride, nonflammable and of high chemical stability, has a high dielectric, and is used widely in electrical and electronic equipment such as circuit breakers, capacitors, microwave components, etc. Sulfur tetrafluoride is used as a fluorinating reagent. Properties, manufacture, and uses are described. Other sulfur fluorides are discussed.

  • Kirk-Othmer Encyclopedia of Chemical Technology - Fluorine Compounds, Inorganic, Fluorosulfuric Acid
    Kirk-Othmer Encyclopedia of Chemical Technology, 2000
    Co-Authors: Francis E. Evans, Ganpat Mani
    Abstract:

    The two most commercially important sulfur-containing inorganic Fluorine Compounds are fluorosulfuric acid and sulfur hexafluoride. Fluorosulfuric acid is used as a fluorinating reagent in the preparation of such Compounds as boron trifluoride and silicon tetrafluoride, and as a catalyst in organic reactions for alkylation, acylation, polymerization, sulfonation, and isomerization. Fluorosulfuric acid is itself a strong acid. When combined with certain inorganic fluorides, the system exhibits superacid properties. Properties, manufacture, and uses are discussed. Of the known sulfur fluorides, sulfur hexafluoride and sulfur tetrafluoride are available commercially. Sulfur hexafluoride, nonflammable and of high chemical stability, has a high dielectric, and is used widely in electrical and electronic equipment such as circuit breakers, capacitors, microwave components, etc. Sulfur tetrafluoride is used as a fluorinating reagent. Properties, manufacture, and uses are described. Other sulfur fluorides are discussed.

Tamotsu Takahashi - One of the best experts on this subject based on the ideXlab platform.

  • halogen exchange reaction of aliphatic Fluorine Compounds with organic halides as halogen source
    Organic Letters, 2015
    Co-Authors: Yuki Mizukami, Zhiyi Song, Tamotsu Takahashi
    Abstract:

    The halogen exchange reaction of aliphatic Fluorine Compounds with organic halides as the halogen source was achieved. Treatment of alkyl fluorides (primary, secondary, or tertiary fluorides) with a catalytic amount of titanocene dihalides, trialkyl aluminum, and polyhalomethanes (chloro or bromo methanes) as the halogen source gave the corresponding alkyl halides in excellent yields under mild conditions. In the case of a Fluorine/iodine exchange, no titanocene catalyst is needed. Only C–F bonds are selectively activated under these conditions, whereas alkyl chlorides, bromides, and iodides are tolerant to these reactions.

William Xavier Bajzer - One of the best experts on this subject based on the ideXlab platform.

  • Kirk‐Othmer Encyclopedia of Chemical Technology - Fluorine Compounds, Organic
    Kirk-Othmer Encyclopedia of Chemical Technology, 2004
    Co-Authors: William Xavier Bajzer
    Abstract:

    The introduction briefly covers the history of organic Fluorine Compounds along with an overview of their commercial impact founded in special chemical properties imparted by the CF bond. Various important synthetic fluorination methods are discussed with an emphasis on global commercial processes, the corresponding plant sites and their production capacities. The changing global marketplace is discussed as CFC (chlorofluorocarbon) use is banned and their replacements are being commercialized. Specific chemicals are shown as examples of the dependence and the diversity of organic Fluorine Compounds within our environment. A summary of safe handling aspects is characterized by a wide range of biological activity and inactivity offered by the examples of this interesting group of chemicals. A bibliography and general reading suggestions complete the subject with the literature search covering information through March, 2004.

  • Kirk-Othmer Encyclopedia of Chemical Technology - Fluorine Compounds, Organic, Introduction
    Kirk-Othmer Encyclopedia of Chemical Technology, 2000
    Co-Authors: William Xavier Bajzer
    Abstract:

    Organic Compounds bearing Fluorine substituents are commercially important in many applications. The refrigerant application is over six decades old and continues to receive wide global attention due to the environmental impact of the chlorofluorocarbon (CFC) materials. Alternative hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) materials are under development to replace the CFCs. The properties of many fluorinated organic Compounds are contrasted with their hydrocarbon analogues. Various methods are described for introduction of Fluorine singly or multiply into organic Compounds. Attention is focused on the recommended commercial method to manufacture many fluorinated organic Compounds. Fluorinated Compounds are discussed by class, with examples given for each. Global production patterns and capacity by company are reviewed along with significant commercial trends. Toxicology of this class of materials is addressed from a brief overview perspective. Bibliographic references and suggestions for general reading are listed. Keywords: Introduction; Fluorine Compounds; organic; Halomethanes; Hydrocarbons; Fluorocarbons; Fluorine substitution; Pharmaceuticals; Herbicides; Insecticides; Fungicides; Safe handling