The Experts below are selected from a list of 12 Experts worldwide ranked by ideXlab platform
Shin-ichi Orimo - One of the best experts on this subject based on the ideXlab platform.
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Halide-stabilized LiBH4, a room-temperature lithium fast-ion conductor
Journal of the American Chemical Society, 2009Co-Authors: Hideki Maekawa, Mariko Ando, Yasuto Noda, Taiki Karahashi, Motoaki Matsuo, Hitoshi Takamura, Shin-ichi OrimoAbstract:Solid state lithium conductors are attracting much attention for their potential applications to solid-state Batteries and supercapacitors of high energy density to overcome safety issues and irreversible capacity loss of the currently commercialized ones. Recently, we discovered a new class of lithium super ionic conductors based on lithium borohydride (LiBH(4)). LiBH(4) was found to have conductivity as high as 10(-2) Scm(-1) accompanied by orthorhombic to hexagonal phase transition above 115 degrees C. Polarization to the lithium metal electrode was shown to be extremely low, providing a versatile anode interface for the battery application. However, the high transition temperature of the superionic phase has limited its applications. Here we show that a chemical modification of LiBH(4) can stabilize the superionic phase even below room temperature. By doping of lithium halides, high conductivity can be obtained at room temperature. Both XRD and NMR confirmed room-temperature stabilization of superionic phase for LiI-doped LiBH(4). The electrochemical measurements showed a great advantage of this material as an extremely lightweight lithium Electrolyte for Batteries of high energy density. This material will open alternative opportunities for the development of solid ionic conductors other than previously known lithium conductors.
J Yan - One of the best experts on this subject based on the ideXlab platform.
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Li/LiFePO4 Batteries with room temperature ionic liquid as Electrolyte
Electrochemistry Communications, 2009Co-Authors: J Jin, J. P. Wei, X. K. Bian, Z. Zhou, H. H. Li, J YanAbstract:Room temperature ionic liquid (RTIL) was prepared on basis of N-methyl-N-butylpiperidinium bis(trifluoromethanesulfonyl)imide (PP14TFSI), which showed a wide electrochemical window (-0.1-5.2 V vs. Li+/Li) and is theoretically feasible as an Electrolyte for Batteries with metallic Li as anodes. The addition of vinylene carbonate (VC) improved the compatibility of PP14TFSI-based Electrolyte towards lithium anodes and enhanced the formation of solid Electrolyte interphase film to protect lithium anodes from corrosion. Accordingly, Li/LiFePO4 cells initially delivered a discharge capacity of about 127 mAh g-1 at a current density of 17 mA g-1 in the ionic liquid with the addition of VC and showed better cyclability than in the neat ionic liquid. Electrochemical impedance spectroscopy disclosed that the addition of VC enhanced Li-ion diffusion and depressed interfacial resistance significantly. © 2009 Elsevier B.V. All rights reserved.
Hideki Maekawa - One of the best experts on this subject based on the ideXlab platform.
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Halide-stabilized LiBH4, a room-temperature lithium fast-ion conductor
Journal of the American Chemical Society, 2009Co-Authors: Hideki Maekawa, Mariko Ando, Yasuto Noda, Taiki Karahashi, Motoaki Matsuo, Hitoshi Takamura, Shin-ichi OrimoAbstract:Solid state lithium conductors are attracting much attention for their potential applications to solid-state Batteries and supercapacitors of high energy density to overcome safety issues and irreversible capacity loss of the currently commercialized ones. Recently, we discovered a new class of lithium super ionic conductors based on lithium borohydride (LiBH(4)). LiBH(4) was found to have conductivity as high as 10(-2) Scm(-1) accompanied by orthorhombic to hexagonal phase transition above 115 degrees C. Polarization to the lithium metal electrode was shown to be extremely low, providing a versatile anode interface for the battery application. However, the high transition temperature of the superionic phase has limited its applications. Here we show that a chemical modification of LiBH(4) can stabilize the superionic phase even below room temperature. By doping of lithium halides, high conductivity can be obtained at room temperature. Both XRD and NMR confirmed room-temperature stabilization of superionic phase for LiI-doped LiBH(4). The electrochemical measurements showed a great advantage of this material as an extremely lightweight lithium Electrolyte for Batteries of high energy density. This material will open alternative opportunities for the development of solid ionic conductors other than previously known lithium conductors.
J Jin - One of the best experts on this subject based on the ideXlab platform.
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Li/LiFePO4 Batteries with room temperature ionic liquid as Electrolyte
Electrochemistry Communications, 2009Co-Authors: J Jin, J. P. Wei, X. K. Bian, Z. Zhou, H. H. Li, J YanAbstract:Room temperature ionic liquid (RTIL) was prepared on basis of N-methyl-N-butylpiperidinium bis(trifluoromethanesulfonyl)imide (PP14TFSI), which showed a wide electrochemical window (-0.1-5.2 V vs. Li+/Li) and is theoretically feasible as an Electrolyte for Batteries with metallic Li as anodes. The addition of vinylene carbonate (VC) improved the compatibility of PP14TFSI-based Electrolyte towards lithium anodes and enhanced the formation of solid Electrolyte interphase film to protect lithium anodes from corrosion. Accordingly, Li/LiFePO4 cells initially delivered a discharge capacity of about 127 mAh g-1 at a current density of 17 mA g-1 in the ionic liquid with the addition of VC and showed better cyclability than in the neat ionic liquid. Electrochemical impedance spectroscopy disclosed that the addition of VC enhanced Li-ion diffusion and depressed interfacial resistance significantly. © 2009 Elsevier B.V. All rights reserved.
Mariko Ando - One of the best experts on this subject based on the ideXlab platform.
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Halide-stabilized LiBH4, a room-temperature lithium fast-ion conductor
Journal of the American Chemical Society, 2009Co-Authors: Hideki Maekawa, Mariko Ando, Yasuto Noda, Taiki Karahashi, Motoaki Matsuo, Hitoshi Takamura, Shin-ichi OrimoAbstract:Solid state lithium conductors are attracting much attention for their potential applications to solid-state Batteries and supercapacitors of high energy density to overcome safety issues and irreversible capacity loss of the currently commercialized ones. Recently, we discovered a new class of lithium super ionic conductors based on lithium borohydride (LiBH(4)). LiBH(4) was found to have conductivity as high as 10(-2) Scm(-1) accompanied by orthorhombic to hexagonal phase transition above 115 degrees C. Polarization to the lithium metal electrode was shown to be extremely low, providing a versatile anode interface for the battery application. However, the high transition temperature of the superionic phase has limited its applications. Here we show that a chemical modification of LiBH(4) can stabilize the superionic phase even below room temperature. By doping of lithium halides, high conductivity can be obtained at room temperature. Both XRD and NMR confirmed room-temperature stabilization of superionic phase for LiI-doped LiBH(4). The electrochemical measurements showed a great advantage of this material as an extremely lightweight lithium Electrolyte for Batteries of high energy density. This material will open alternative opportunities for the development of solid ionic conductors other than previously known lithium conductors.