The Experts below are selected from a list of 1332 Experts worldwide ranked by ideXlab platform
Masataka Wakihara - One of the best experts on this subject based on the ideXlab platform.
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stability of lithium polymer battery based on substituted spinel cathode and peg Borate Ester pc plasticized polymer electrolyte
Journal of The Electrochemical Society, 2005Co-Authors: I R M Kottegoda, Zhumabay Bakenov, Hiromasa Ikuta, Masataka WakiharaAbstract:The possible application of a novel plasticized polymer electrolyte in lithium battery based on substituted spinel cathode was investigated. The polymer electrolyte was prepared by dissolving LiClO 4 in the host polymer, poly(ethylene glycol) methacrylates (PEGMs) plasticized by both propylene carbonate (PC) and poly(ethylene glycol)-Borate Ester (PEG-BE) of various compositions. The ionic conductivity σ of the polymer is enhanced with the addition of PC, while the lithium ion transference number t L i + reaches an optimum in a mixture of 49% PEG-BE and 21% of PC in the polymer weight. PEG-BE has been recognized to interact with anion as a Lewis acid, which leads to high lithium ion conductivity. The observed trend of σ and t L i + with decreasing PEG-BE is suggested as being due to enhancement of anion conductivity in the medium as a result of low viscous and high dielectric properties of PC coupled with suppressed Lewis acid interaction of PEG-BE. The cycle performance and the storage stability of the Li/polymer electrolyte/LiMn 1 . 8 Co 0 . 2 O 4 cell comprising the above electrolyte were found to be quite acceptable for practical utility.
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Electrochemical Performance of Lithium Polymer Battery Based on PC/Polymer Borate Ester Plasticizers
Electrochemical and Solid State Letters, 2005Co-Authors: I R M Kottegoda, Zhumabay Bakenov, Hiromasa Ikuta, Yoshiharu Uchimoto, Masataka WakiharaAbstract:The electrochemical performance of a lithium polymer battery based on a novel gel polymer electrolyte and a substituted spinel cathode was investigated. Propylene carbonate (PC) and poly(ethylene glycol)-Borate Ester (PEG-BE) were used as plasticizers in the polymer electrolyte composed of poly (ethylene glycol) methacrylates (PEG-Ms) and LiClO 4 . The electrolyte exhibited satisfactory thermal, mechanical, and electrochemical stability. The Li/PC/PEG-BE based polymer electrolyte/LiMn 1 . 8 co 0 . 2 O 4 cell generated a reasonable steady capacity at room temperature and a substantial rate capability at 65°C.
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ionic conductivity and transport number of lithium ion in polymer electrolytes containing peg Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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Ionic conductivity and transport number of lithium ion in polymer electrolytes containing PEG–Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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interaction between the lewis acid group of a Borate Ester and various anion species in a polymer electrolyte containing mg salt
Journal of Physical Chemistry B, 2003Co-Authors: Morihiro Saito, Hiromasa Ikuta, Masataka Wakihara, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masahiro YamamotoAbstract:To clarify the interaction between a Lewis acid and anionic species of the supporting salt incorporated in a polymer electrolyte, we designed a novel solid polymer electrolyte based on Mg salt complexes of poly(ethylene glycol) (PEO) chains cross-linked by a Borate Ester group as a Lewis acid and examined the ionic conduction mechanism of the electrolyte. Mg(ClO4)2, Mg(CF3SO3)2, and Mg[(CF3SO2)2N]2 were used as the Mg salt. To change the concentration of the Lewis acid in the polymer electrolyte, two different lengths of PEG chains, which were cross-linked by Borate Ester group, were used. By estimating the transport number of the Mg2+ cation (tMg2+) of the electrolytes, it was found that the Borate Ester group interacts with anions with the consequence that tMg2+ increases with increasing concentration of Borate Ester group. By measuring Raman spectra for the electrolyte containing Mg(ClO4)2 salt, it was also found that the concentration of the free ClO4- anion increased with the increasing concentration...
Hiromasa Ikuta - One of the best experts on this subject based on the ideXlab platform.
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stability of lithium polymer battery based on substituted spinel cathode and peg Borate Ester pc plasticized polymer electrolyte
Journal of The Electrochemical Society, 2005Co-Authors: I R M Kottegoda, Zhumabay Bakenov, Hiromasa Ikuta, Masataka WakiharaAbstract:The possible application of a novel plasticized polymer electrolyte in lithium battery based on substituted spinel cathode was investigated. The polymer electrolyte was prepared by dissolving LiClO 4 in the host polymer, poly(ethylene glycol) methacrylates (PEGMs) plasticized by both propylene carbonate (PC) and poly(ethylene glycol)-Borate Ester (PEG-BE) of various compositions. The ionic conductivity σ of the polymer is enhanced with the addition of PC, while the lithium ion transference number t L i + reaches an optimum in a mixture of 49% PEG-BE and 21% of PC in the polymer weight. PEG-BE has been recognized to interact with anion as a Lewis acid, which leads to high lithium ion conductivity. The observed trend of σ and t L i + with decreasing PEG-BE is suggested as being due to enhancement of anion conductivity in the medium as a result of low viscous and high dielectric properties of PC coupled with suppressed Lewis acid interaction of PEG-BE. The cycle performance and the storage stability of the Li/polymer electrolyte/LiMn 1 . 8 Co 0 . 2 O 4 cell comprising the above electrolyte were found to be quite acceptable for practical utility.
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Electrochemical Performance of Lithium Polymer Battery Based on PC/Polymer Borate Ester Plasticizers
Electrochemical and Solid State Letters, 2005Co-Authors: I R M Kottegoda, Zhumabay Bakenov, Hiromasa Ikuta, Yoshiharu Uchimoto, Masataka WakiharaAbstract:The electrochemical performance of a lithium polymer battery based on a novel gel polymer electrolyte and a substituted spinel cathode was investigated. Propylene carbonate (PC) and poly(ethylene glycol)-Borate Ester (PEG-BE) were used as plasticizers in the polymer electrolyte composed of poly (ethylene glycol) methacrylates (PEG-Ms) and LiClO 4 . The electrolyte exhibited satisfactory thermal, mechanical, and electrochemical stability. The Li/PC/PEG-BE based polymer electrolyte/LiMn 1 . 8 co 0 . 2 O 4 cell generated a reasonable steady capacity at room temperature and a substantial rate capability at 65°C.
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ionic conductivity and transport number of lithium ion in polymer electrolytes containing peg Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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Ionic conductivity and transport number of lithium ion in polymer electrolytes containing PEG–Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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interaction between the lewis acid group of a Borate Ester and various anion species in a polymer electrolyte containing mg salt
Journal of Physical Chemistry B, 2003Co-Authors: Morihiro Saito, Hiromasa Ikuta, Masataka Wakihara, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masahiro YamamotoAbstract:To clarify the interaction between a Lewis acid and anionic species of the supporting salt incorporated in a polymer electrolyte, we designed a novel solid polymer electrolyte based on Mg salt complexes of poly(ethylene glycol) (PEO) chains cross-linked by a Borate Ester group as a Lewis acid and examined the ionic conduction mechanism of the electrolyte. Mg(ClO4)2, Mg(CF3SO3)2, and Mg[(CF3SO2)2N]2 were used as the Mg salt. To change the concentration of the Lewis acid in the polymer electrolyte, two different lengths of PEG chains, which were cross-linked by Borate Ester group, were used. By estimating the transport number of the Mg2+ cation (tMg2+) of the electrolytes, it was found that the Borate Ester group interacts with anions with the consequence that tMg2+ increases with increasing concentration of Borate Ester group. By measuring Raman spectra for the electrolyte containing Mg(ClO4)2 salt, it was also found that the concentration of the free ClO4- anion increased with the increasing concentration...
Yuki Kato - One of the best experts on this subject based on the ideXlab platform.
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ionic conductivity and transport number of lithium ion in polymer electrolytes containing peg Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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Ionic conductivity and transport number of lithium ion in polymer electrolytes containing PEG–Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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Influence of Lewis acidic Borate Ester groups on lithium ionic conduction in polymer electrolytes
Journal of Materials Chemistry, 2002Co-Authors: Yuki Kato, Hiromasa Ikuta, Masataka Wakihara, Yoshiharu Uchimoto, Shoichi Yokoyama, Kentaro Suwa, Takeshi Yabe, Masahiro YamamotoAbstract:Polymer electrolytes having Borate Ester groups, which are part of the polymer matrix, have been prepared. The transference number of the lithium ions increases with increasing concentration of the Borate Ester groups, and therefore it is considered that the Borate Ester groups, having Lewis acidity, interact with Lewis basic anions. Furthermore, the transference numbers of lithium ions in the polymer electrolytes containing LiCF3SO3 or LiClO4 were found to be higher than that in the electrolyte with LiN(CF3SO2)2. Ab initio calculations were performed to estimate the interactions between the Borate Ester groups and the anions. The calculated results indicate that the Borate Ester group prefers to interact with a ‘hard’ basic anion, CF3SO3− or ClO4−. This is in good agreement with the obtained experimental results.
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thermally stable solid polymer electrolyte containing Borate Ester groups for lithium secondary battery
Solid State Ionics, 2002Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Kentaro Suwa, Takeshi Yabe, Masataka WakiharaAbstract:Abstract A novel polymer electrolyte having Borate Ester groups, which are fixed to the backbone chain of the polymer, was prepared. The backbone polymer was synthesized by reaction between polyethylene glycol and boric acid anhydride. The highest conductivity was found for the polymer electrolyte sample prepared by the polyethylene glycol having average molecular weight of 600 (PEG600), the values of the ionic conductivity were 5.8×10 −5 S cm −1 at 30 °C and 2.6×10 −4 S cm −1 at 60 °C, respectively. The solid polymer electrolytes have relatively high thermal stability and electrochemical stability.
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Polymer electrolyte plasticized with PEG-Borate Ester having high ionic conductivity and thermal stability
Solid State Ionics, 2002Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Kohji Hasumi, Masataka WakiharaAbstract:Abstract We have focused on the PEG-Borate Ester as a new type of plasticizer for solid polymer electrolyte composed of poly(ethyleneglycol) methacrylate (PEGMA) and lithium bis-trifluoromethanesulfonimide (LiTFSI). The PEG-Borate Ester shows good thermal stability and high flash point. Ionic conductivity of the polymer electrolyte increases with increasing amount of the PEG-Borate Ester and exhibits values greater than 10−4 S cm−1 at 30 °C and 10−3 S cm−1 at 60 °C. Furthermore, PEG-Borate Ester has three EO chains whose lengths are variable, and various ionic conductivities are expected to depend on EO chain length. As a result, polymer electrolyte containing the PEG-Borate Ester whose EO chain length is n=3 shows highest ionic conductivity. Furthermore, polymer electrolytes containing PEG-Borate Esters show excellent thermal and electrochemical stability. The electrolytes are thermally stable up to 300 °C and electrochemically up to 4.5 V vs. Li+/Li.
Yoshiharu Uchimoto - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical Performance of Lithium Polymer Battery Based on PC/Polymer Borate Ester Plasticizers
Electrochemical and Solid State Letters, 2005Co-Authors: I R M Kottegoda, Zhumabay Bakenov, Hiromasa Ikuta, Yoshiharu Uchimoto, Masataka WakiharaAbstract:The electrochemical performance of a lithium polymer battery based on a novel gel polymer electrolyte and a substituted spinel cathode was investigated. Propylene carbonate (PC) and poly(ethylene glycol)-Borate Ester (PEG-BE) were used as plasticizers in the polymer electrolyte composed of poly (ethylene glycol) methacrylates (PEG-Ms) and LiClO 4 . The electrolyte exhibited satisfactory thermal, mechanical, and electrochemical stability. The Li/PC/PEG-BE based polymer electrolyte/LiMn 1 . 8 co 0 . 2 O 4 cell generated a reasonable steady capacity at room temperature and a substantial rate capability at 65°C.
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ionic conductivity and transport number of lithium ion in polymer electrolytes containing peg Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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Ionic conductivity and transport number of lithium ion in polymer electrolytes containing PEG–Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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interaction between the lewis acid group of a Borate Ester and various anion species in a polymer electrolyte containing mg salt
Journal of Physical Chemistry B, 2003Co-Authors: Morihiro Saito, Hiromasa Ikuta, Masataka Wakihara, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masahiro YamamotoAbstract:To clarify the interaction between a Lewis acid and anionic species of the supporting salt incorporated in a polymer electrolyte, we designed a novel solid polymer electrolyte based on Mg salt complexes of poly(ethylene glycol) (PEO) chains cross-linked by a Borate Ester group as a Lewis acid and examined the ionic conduction mechanism of the electrolyte. Mg(ClO4)2, Mg(CF3SO3)2, and Mg[(CF3SO2)2N]2 were used as the Mg salt. To change the concentration of the Lewis acid in the polymer electrolyte, two different lengths of PEG chains, which were cross-linked by Borate Ester group, were used. By estimating the transport number of the Mg2+ cation (tMg2+) of the electrolytes, it was found that the Borate Ester group interacts with anions with the consequence that tMg2+ increases with increasing concentration of Borate Ester group. By measuring Raman spectra for the electrolyte containing Mg(ClO4)2 salt, it was also found that the concentration of the free ClO4- anion increased with the increasing concentration...
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influence of peg Borate Ester as a lewis acid on ionic conductivity of polymer electrolyte containing mg salt
Journal of The Electrochemical Society, 2003Co-Authors: Morihiro Saito, Hiromasa Ikuta, Masataka Wakihara, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masahiro YamamotoAbstract:We produced a novel Mg 2+ conducting polymer electrolyte and added a poly(ethylene glycol) (PEG)-Borate Ester as a new type plasticizer having a Lewis acidity and investigated the influence of the Lewis acidity of the PEG-BorateEster to a solid polymer electrolyte containing Mg(ClO 4 ) 2 salt. Adding the PEG-Borate Ester into the electrolyte shows the increase in the ionic conductivity of the polymer electrolyte. By measuring the glass transition temperature ( T g ) of the polymer electrolytes using differential scanning calorimetry, it became clear that the mobility of the carrier ion increases with increasing the amount of the PEG-Borate Ester. By investigating the temperature dependence of the ionic conductivity using William-Landel-Ferry type equation and measuring Raman spectra of the polymer electrolytes, it was found that the concentration of the carrier ion increases with increasing the amount of the PEG-Borate Ester in the polymer electrolyte. Furthermore, by estimating the transference number of the Mg 2+ cation and performing the ab initio calculation for the PEG-Borate Ester, it is suggested that the PEG-Borate Ester may enhance the degree of dissociation of the Mg salt in the polymer electrolyte to increase the ratio of the free ion, especially Mg 2+ , by interacting with and trapping the ClO 4 - anion of the salt as a Lewis acid.
Shoichi Yokoyama - One of the best experts on this subject based on the ideXlab platform.
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ionic conductivity and transport number of lithium ion in polymer electrolytes containing peg Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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Ionic conductivity and transport number of lithium ion in polymer electrolytes containing PEG–Borate Ester
Electrochimica Acta, 2004Co-Authors: Yuki Kato, Hiromasa Ikuta, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masataka WakiharaAbstract:Abstract We investigated the effects of PEG–Borate Ester on the ionic conductivity and transport number of lithium ions in polymer electrolytes with Li-salt, such as LiN(CF 3 SO 2 ) 2 , LiClO 4 or LiCF 3 SO 3 . The ionic conductivity of the polymer electrolyte with LiN(CF 3 SO 2 ) 2 was found to be higher than those of the electrolytes with LiClO 4 or LiCF 3 SO 3 . This result is mainly concerned with mobility of ions, which is indicated by the comparison of glass transition temperatures of the polymer electrolytes. On the other hand, the transport numbers of lithium ions in the polymer electrolytes with LiClO 4 or LiCF 3 SO 3 were higher than those of the electrolyte with LiN(CF 3 SO 3 ) 2 . Furthermore, the conductivities of lithium ions calculated by multiplying the ionic conductivity measured by ac impedance with transport number of lithium ions were also found to be higher than that of the electrolytes with LiN(CF 3 SO 2 ). These results indicate that the PEG–Borate Ester acts as Lewis acid and interacts with CF 3 SO 3 − or ClO 4 − more effectively compared with N(CF 3 SO 2 ) 2 − , leading to improved dissociation of Li-salts and transport number of lithium ions.
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interaction between the lewis acid group of a Borate Ester and various anion species in a polymer electrolyte containing mg salt
Journal of Physical Chemistry B, 2003Co-Authors: Morihiro Saito, Hiromasa Ikuta, Masataka Wakihara, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masahiro YamamotoAbstract:To clarify the interaction between a Lewis acid and anionic species of the supporting salt incorporated in a polymer electrolyte, we designed a novel solid polymer electrolyte based on Mg salt complexes of poly(ethylene glycol) (PEO) chains cross-linked by a Borate Ester group as a Lewis acid and examined the ionic conduction mechanism of the electrolyte. Mg(ClO4)2, Mg(CF3SO3)2, and Mg[(CF3SO2)2N]2 were used as the Mg salt. To change the concentration of the Lewis acid in the polymer electrolyte, two different lengths of PEG chains, which were cross-linked by Borate Ester group, were used. By estimating the transport number of the Mg2+ cation (tMg2+) of the electrolytes, it was found that the Borate Ester group interacts with anions with the consequence that tMg2+ increases with increasing concentration of Borate Ester group. By measuring Raman spectra for the electrolyte containing Mg(ClO4)2 salt, it was also found that the concentration of the free ClO4- anion increased with the increasing concentration...
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influence of peg Borate Ester as a lewis acid on ionic conductivity of polymer electrolyte containing mg salt
Journal of The Electrochemical Society, 2003Co-Authors: Morihiro Saito, Hiromasa Ikuta, Masataka Wakihara, Yoshiharu Uchimoto, Shoichi Yokoyama, Takeshi Yabe, Masahiro YamamotoAbstract:We produced a novel Mg 2+ conducting polymer electrolyte and added a poly(ethylene glycol) (PEG)-Borate Ester as a new type plasticizer having a Lewis acidity and investigated the influence of the Lewis acidity of the PEG-BorateEster to a solid polymer electrolyte containing Mg(ClO 4 ) 2 salt. Adding the PEG-Borate Ester into the electrolyte shows the increase in the ionic conductivity of the polymer electrolyte. By measuring the glass transition temperature ( T g ) of the polymer electrolytes using differential scanning calorimetry, it became clear that the mobility of the carrier ion increases with increasing the amount of the PEG-Borate Ester. By investigating the temperature dependence of the ionic conductivity using William-Landel-Ferry type equation and measuring Raman spectra of the polymer electrolytes, it was found that the concentration of the carrier ion increases with increasing the amount of the PEG-Borate Ester in the polymer electrolyte. Furthermore, by estimating the transference number of the Mg 2+ cation and performing the ab initio calculation for the PEG-Borate Ester, it is suggested that the PEG-Borate Ester may enhance the degree of dissociation of the Mg salt in the polymer electrolyte to increase the ratio of the free ion, especially Mg 2+ , by interacting with and trapping the ClO 4 - anion of the salt as a Lewis acid.
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Influence of Lewis acidic Borate Ester groups on lithium ionic conduction in polymer electrolytes
Journal of Materials Chemistry, 2002Co-Authors: Yuki Kato, Hiromasa Ikuta, Masataka Wakihara, Yoshiharu Uchimoto, Shoichi Yokoyama, Kentaro Suwa, Takeshi Yabe, Masahiro YamamotoAbstract:Polymer electrolytes having Borate Ester groups, which are part of the polymer matrix, have been prepared. The transference number of the lithium ions increases with increasing concentration of the Borate Ester groups, and therefore it is considered that the Borate Ester groups, having Lewis acidity, interact with Lewis basic anions. Furthermore, the transference numbers of lithium ions in the polymer electrolytes containing LiCF3SO3 or LiClO4 were found to be higher than that in the electrolyte with LiN(CF3SO2)2. Ab initio calculations were performed to estimate the interactions between the Borate Ester groups and the anions. The calculated results indicate that the Borate Ester group prefers to interact with a ‘hard’ basic anion, CF3SO3− or ClO4−. This is in good agreement with the obtained experimental results.