WO2022070312A1 - 電解液及び電気化学デバイス - Google Patents

電解液及び電気化学デバイス Download PDF

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WO2022070312A1
WO2022070312A1 PCT/JP2020/037170 JP2020037170W WO2022070312A1 WO 2022070312 A1 WO2022070312 A1 WO 2022070312A1 JP 2020037170 W JP2020037170 W JP 2020037170W WO 2022070312 A1 WO2022070312 A1 WO 2022070312A1
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electrolytic solution
mass
atom
solution according
group
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PCT/JP2020/037170
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English (en)
French (fr)
Japanese (ja)
Inventor
秀之 小川
真也 中村
馨 今野
薫平 山田
保彦 吉成
允哉 砂入
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昭和電工マテリアルズ株式会社
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Priority to PCT/JP2020/037170 priority Critical patent/WO2022070312A1/ja
Priority to JP2022553306A priority patent/JP7647766B2/ja
Publication of WO2022070312A1 publication Critical patent/WO2022070312A1/ja

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • This disclosure relates to electrolytes and electrochemical devices.
  • Patent Document 1 discloses an electrolytic solution for a non-aqueous electrolytic solution battery containing a specific siloxane compound in order to improve cycle characteristics and internal resistance characteristics.
  • One aspect of the present invention is to provide an electrolytic solution capable of improving the performance of an electrochemical device.
  • R 1 and R 2 each independently represent a monovalent hydrocarbon group or a halogen atom which may be substituted with a halogen atom
  • R 3 represents an alkylene group
  • R 4 represents an alkylene group.
  • R 1 and R 2 may each independently represent an unsubstituted monovalent hydrocarbon group.
  • R 3 may represent a linear alkylene group.
  • R 3 may represent an alkylene group having 2 or more carbon atoms.
  • R4 may represent a hydrogen atom.
  • R4 may represent a halogen atom.
  • R4 may represent a silyl group.
  • the silyl group may be represented by the following formula (1a).
  • R 41 to R 43 each independently represent a monovalent hydrocarbon group or a halogen atom which may be substituted with a halogen atom.
  • the total number of carbon atoms in the compound represented by the formula (1) may be 4 or more.
  • R 1 and R 2 may represent a methyl group
  • R 3 may represent a linear alkylene group having 2 or more carbon atoms
  • R 4 may represent a hydrogen atom or a halogen atom.
  • the R 4 may be a hydrogen atom.
  • Lithium salts include LiPF 6 , LiBF 4 , LiClO 4 , LiB (C 6 H 5 ) 4 , LiCH 3 SO 3 , CF 3 SO 2 OLi, LiN (SO 2 F) 2 , LiN (SO 2 CF 3) 2, LiN (SO 2 CF 3 ) 2 , And LiN (SO 2 CF 2 CF 3 ) 2 may contain at least one selected from the group consisting of 2.
  • the lithium salt may include a lithium salt of a cyclic compound having a ring containing a boron atom or a phosphorus atom.
  • the lithium salt may contain a lithium salt of a compound having a fluorine atom, an oxygen atom and a phosphorus atom.
  • the electrolytic solution may further contain an additive different from the compound represented by the formula (1) and the lithium salt, and the content of the additive may be 10% by mass or less based on the total amount of the electrolytic solution.
  • the additive may contain a cyclic compound having a carbon-carbon double bond.
  • the additive may include a cyclic compound having a fluorine atom.
  • the additive may include a cyclic compound having a sulfur atom.
  • the additive may include a nitrile compound.
  • Another aspect of the present invention is an electrochemical device including a positive electrode, a negative electrode, and the above-mentioned electrolytic solution.
  • an electrolytic solution capable of improving the performance of an electrochemical device.
  • FIG. 1 It is a perspective view which shows the non-aqueous electrolyte secondary battery as an electrochemical device which concerns on one Embodiment. It is an exploded perspective view which shows the electrode group of the secondary battery shown in FIG.
  • FIG. 1 is a perspective view showing an electrochemical device according to an embodiment.
  • the electrochemical device is a non-aqueous electrolyte secondary battery.
  • the non-aqueous electrolytic solution secondary battery 1 includes an electrode group 2 composed of a positive electrode, a negative electrode, and a separator, and a bag-shaped battery exterior body 3 accommodating the electrode group 2.
  • the positive electrode and the negative electrode are provided with a positive electrode current collecting tab 4 and a negative electrode current collecting tab 5, respectively.
  • the positive electrode current collecting tab 4 and the negative electrode current collecting tab 5 project from the inside of the battery exterior 3 to the outside so that the positive electrode and the negative electrode can be electrically connected to the outside of the non-aqueous electrolyte secondary battery 1, respectively. ..
  • the battery exterior 3 is filled with an electrolytic solution (not shown).
  • the non-aqueous electrolyte secondary battery 1 may be a battery (coin type, cylindrical type, laminated type, etc.) having a shape other than the so-called “laminated type” as described above.
  • the battery exterior 3 may be, for example, a container made of a laminated film.
  • the laminated film may be, for example, a laminated film in which a resin film such as a polyethylene terephthalate (PET) film, a metal foil such as aluminum, copper, and stainless steel, and a sealant layer such as polypropylene are laminated in this order.
  • PET polyethylene terephthalate
  • metal foil such as aluminum, copper, and stainless steel
  • a sealant layer such as polypropylene
  • FIG. 2 is an exploded perspective view showing an embodiment of the electrode group 2 in the non-aqueous electrolyte secondary battery 1 shown in FIG. 1.
  • the electrode group 2 includes a positive electrode 6, a separator 7, and a negative electrode 8 in this order.
  • the positive electrode 6 and the negative electrode 8 are arranged so that the surfaces of the positive electrode mixture layer 10 side and the negative electrode mixture layer 12 side face each other with the separator 7.
  • the positive electrode 6 includes a positive electrode current collector 9 and a positive electrode mixture layer 10 provided on the positive electrode current collector 9.
  • the positive electrode current collector 9 is provided with a positive electrode current collector tab 4.
  • the positive electrode current collector 9 is made of, for example, aluminum, titanium, stainless steel, nickel, calcined carbon, a conductive polymer, conductive glass, or the like.
  • the positive electrode current collector 9 may have a surface of aluminum, copper or the like treated with carbon, nickel, titanium, silver or the like for the purpose of improving adhesiveness, conductivity and oxidation resistance.
  • the thickness of the positive electrode current collector 9 is, for example, 1 to 50 ⁇ m in terms of electrode strength and energy density.
  • the positive electrode mixture layer 10 contains a positive electrode active material, a conductive agent, and a binder.
  • the thickness of the positive electrode mixture layer 10 is, for example, 20 to 200 ⁇ m.
  • the positive electrode active material may be, for example, lithium oxide.
  • the lithium oxide include Li x CoO 2 , Li x NiO 2 , Li x MnO 2 , Li x Coy Ni 1-y O 2 , Li x Coy M 1-y Oz , and Li x Ni 1- . y My O z , Li x Mn 2 O 4 and Li x Mn 2- y My O 4 (In each formula, M is Na, Mg, Sc, Y , Mn, Fe, Co, Cu, Zn, Al. , Cr, Pb, Sb, V and at least one element selected from the group consisting of B (where M is an element different from the other elements in each equation).
  • X 0 to 1.2.
  • the positive electrode active material may be, for example, a phosphate of lithium.
  • phosphate phosphate include lithium manganese phosphate (LiMnPO 4 ), lithium iron phosphate (LiFePO 4 ), lithium cobalt phosphate (LiCoPO 4 ) and lithium vanadium phosphate (Li 3 V 2 (PO 4 )). 3 ) can be mentioned.
  • the content of the positive electrode active material may be 80% by mass or more, 85% by mass or more, or 99% by mass or less, based on the total amount of the positive electrode mixture layer.
  • the conductive agent may be carbon black such as acetylene black or ketjen black, or a carbon material such as graphite, graphene or carbon nanotube.
  • the content of the conductive agent may be, for example, 0.01% by mass or more, 0.1% by mass or more, or 1% by mass or more, and 50% by mass or less, 30% by mass, based on the total amount of the positive electrode mixture layer. It may be less than or equal to 15% by mass or less.
  • the binder is, for example, a resin such as polyethylene, polypropylene, polyethylene terephthalate, polymethylmethacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluororubber. , Isoprene rubber, butadiene rubber, rubber such as ethylene-propylene rubber; styrene / butadiene / styrene block copolymer or its hydrogen additive, EPDM (ethylene / propylene / diene ternary copolymer), styrene / ethylene / butadiene.
  • a resin such as polyethylene, polypropylene, polyethylene terephthalate, polymethylmethacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene
  • Thermoplastic elastomers such as ethylene copolymers, styrene / isoprene / styrene block copolymers or hydrogenated products thereof; syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymers, propylene / ⁇ -Soft resins such as olefin copolymers; polyvinylidene fluoride (PVDF), polytetrafluoroethylene, fluorinated vinylidene fluoride, polytetrafluoroethylene / ethylene copolymer, polytetrafluoroethylene / vinylidene fluoride copolymer, etc.
  • PVDF polyvinylidene fluoride
  • Fluoro-containing resin a resin having a nitrile group-containing monomer as a monomer unit; a polymer composition having ionic conductivity of an alkali metal ion (for example, lithium ion) and the like can be mentioned.
  • the content of the binder may be, for example, 0.1% by mass or more, 1% by mass or more, or 1.5% by mass or more, and is 30% by mass or less and 20% by mass, based on the total amount of the positive electrode mixture layer. % Or less, or 10% by mass or less.
  • the separator 7 is particularly limited as long as it electronically insulates between the positive electrode 6 and the negative electrode 8 while allowing ions to permeate and has resistance to oxidizing property on the positive electrode 6 side and reducing property on the negative electrode 8 side. Not done.
  • Examples of the material (material) of such a separator 7 include resins and inorganic substances.
  • the separator 7 is preferably a porous sheet or a non-woven fabric made of a polyolefin such as polyethylene or polypropylene from the viewpoint of being stable to an electrolytic solution and having excellent liquid retention.
  • the inorganic substance examples include oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate.
  • the separator 7 may be, for example, a separator in which a fibrous or particulate inorganic substance is attached to a thin film-like substrate such as a non-woven fabric, a woven fabric, or a microporous film.
  • the negative electrode 8 includes a negative electrode current collector 11 and a negative electrode mixture layer 12 provided on the negative electrode current collector 11.
  • the negative electrode current collector 11 is provided with a negative electrode current collector tab 5.
  • the negative electrode current collector 11 is made of copper, stainless steel, nickel, aluminum, titanium, calcined carbon, a conductive polymer, conductive glass, an aluminum-cadmium alloy, or the like.
  • the negative electrode current collector 11 may have a surface of copper, aluminum, or the like treated with carbon, nickel, titanium, silver, or the like for the purpose of improving adhesiveness, conductivity, and reduction resistance.
  • the thickness of the negative electrode current collector 11 is, for example, 1 to 50 ⁇ m in terms of electrode strength and energy density.
  • the negative electrode mixture layer 12 contains, for example, a negative electrode active material and a binder.
  • the negative electrode active material is not particularly limited as long as it is a substance that can occlude and release lithium ions.
  • the negative electrode active material include carbon materials, metal composite oxides, oxides or nitrides of Group 4 elements such as tin, germanium, and silicon, elemental lithium, lithium alloys such as lithium aluminum alloys, Sn, Si, and the like. Examples include metals that can form alloys with lithium.
  • the negative electrode active material is preferably at least one selected from the group consisting of a carbon material and a metal composite oxide.
  • the negative electrode active material may be one of these alone or a mixture of two or more thereof.
  • the shape of the negative electrode active material may be, for example, particulate.
  • the carbon material examples include amorphous carbon material, natural graphite, composite carbon material in which a film of amorphous carbon material is formed on natural graphite, artificial graphite (resin raw material such as epoxy resin and phenol resin, petroleum, coal, etc.). (A product obtained by firing a pitch-based raw material obtained from) and the like.
  • the metal composite oxide preferably contains either one or both of titanium and lithium, and more preferably lithium.
  • the carbon material has high conductivity and is particularly excellent in low temperature characteristics and cycle stability.
  • graphite is preferable from the viewpoint of increasing the capacity.
  • the carbon mesh surface layer (d002) in the X-ray wide-angle diffraction method is preferably less than 0.34 nm, and more preferably 0.3354 nm or more and 0.337 nm or less.
  • a carbon material satisfying such conditions may be referred to as pseudoanisotropic carbon.
  • the negative electrode active material may further contain a material containing at least one element selected from the group consisting of silicon and tin.
  • the material containing at least one element selected from the group consisting of silicon and tin may be a simple substance of silicon or tin, or a compound containing at least one element selected from the group consisting of silicon and tin.
  • the compound may be an alloy containing at least one element selected from the group consisting of silicon and tin, for example, in addition to silicon and tin, nickel, copper, iron, cobalt, manganese, zinc, indium and silver. , Titanium, germanium, bismuth, antimony and chromium.
  • the compound containing at least one element selected from the group consisting of silicon and tin may be an oxide, a nitride, or a carbide, and specifically, for example, silicon oxidation of SiO, SiO 2 , LiSiO, etc. It may be a substance, a silicon nitride such as Si 3 N 4 , Si 2 N 2 O, a silicon carbide such as SiC, a tin oxide such as SnO, SnO 2 , LiSnO, or the like.
  • the negative electrode 8 preferably contains a carbon material as a negative electrode active material, more preferably contains graphite, and further preferably contains a carbon material, silicon and the like. It contains a mixture with a material containing at least one element selected from the group consisting of tin, and particularly preferably contains a mixture of graphite and silicon oxide.
  • the content of the carbon material (graphite) in the material (silicon oxide) containing at least one element selected from the group consisting of silicon and tin in the mixture is 1% by mass or more, or 3 based on the total amount of the mixture. It may be 3% by mass or more and 30% by mass or less.
  • the content of the negative electrode active material may be 80% by mass or more, 85% by mass or more, or 99% by mass or less, based on the total amount of the negative electrode mixture layer.
  • the binder and its content may be the same as the binder and its content in the above-mentioned positive electrode mixture layer.
  • the negative electrode mixture layer 12 may contain a thickener in order to adjust the viscosity.
  • the thickener is not particularly limited, but may be carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, salts thereof and the like.
  • the thickener may be one of these alone or a mixture of two or more thereof.
  • the content thereof is not particularly limited.
  • the content of the thickener may be 0.1% by mass or more, preferably 0.2% by mass or more, based on the total amount of the negative electrode mixture layer from the viewpoint of coatability of the negative electrode mixture layer. , More preferably 0.5% by mass or more.
  • the content of the thickener may be 5% by mass or less, preferably 3% by mass, based on the total amount of the negative electrode mixture layer from the viewpoint of suppressing a decrease in battery capacity or an increase in resistance between negative electrode active materials. % Or less, more preferably 2% by mass or less.
  • the electrolytic solution contains a compound represented by the following formula (1), a lithium salt, and a non-aqueous solvent.
  • R 1 and R 2 each independently represent a monovalent hydrocarbon group or a halogen atom which may be substituted with a halogen atom
  • R 3 represents an alkylene group
  • R 4 represents an alkylene group.
  • the “monovalent hydrocarbon group optionally substituted with a halogen atom” represented by R 1 and R 2 is an unsubstituted monovalent hydrocarbon group or a hydrogen atom in the monovalent hydrocarbon group. At least one of the above is a monovalent hydrocarbon group substituted with a halogen atom (hereinafter, also referred to as “hydrocarbon substituted monovalent hydrocarbon group”).
  • the monovalent hydrocarbon group may be, for example, an alkyl group or an aryl group.
  • the alkyl group may be linear or branched.
  • the number of carbon atoms of the monovalent hydrocarbon group may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, or 6 or more, and 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 It may be less than or equal to or less than or equal to 2.
  • the halogen atom in the halogen-substituted monovalent hydrocarbon group may be, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, may be a fluorine atom or a chlorine atom, or may be a fluorine atom.
  • the number of halogen atoms in the halogen-substituted monovalent hydrocarbon group may be 1 or more, 2 or more, 3 or more, or 4 or more, and may be 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less. It's okay.
  • the halogen atom represented by R 1 and R 2 may be, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, may be a fluorine atom or a chlorine atom, or may be a fluorine atom.
  • the alkylene group represented by R 3 may be linear or branched.
  • the carbon number of the alkylene group may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, or 6 or more, and is 12 or less, 11 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less. It may be 5, 4 or less, or 3 or less.
  • the halogen atom represented by R4 may be, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, may be a fluorine atom or a chlorine atom, or may be a fluorine atom.
  • R4 is represented by, for example, the following formula (1a).
  • R 41 to R 43 each independently represent a monovalent hydrocarbon group or a halogen atom which may be substituted with a halogen atom.
  • the "monovalent hydrocarbon group optionally substituted with a halogen atom" represented by R 41 to R 43 is an unsubstituted monovalent hydrocarbon group or a halogen-substituted monovalent hydrocarbon group.
  • the monovalent hydrocarbon group may be, for example, an alkyl group or an aryl group.
  • the alkyl group may be linear or branched.
  • the number of carbon atoms of the monovalent hydrocarbon group may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, or 6 or more, and 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 It may be less than or equal to or less than or equal to 2.
  • the halogen atom in the halogen-substituted monovalent hydrocarbon group may be, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, may be a fluorine atom or a chlorine atom, or may be a fluorine atom.
  • the number of halogen atoms in the halogen-substituted monovalent hydrocarbon group may be 1 or more, 2 or more, 3 or more, or 4 or more, and may be 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less. It's okay.
  • the halogen atom represented by R 41 to R 43 may be, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, may be a fluorine atom or a chlorine atom, or may be a fluorine atom.
  • the total number of carbon atoms in the compound represented by the formula (1) may be 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more, and is 20 or less, 19 or less, 18 or less. , 17 or less, 16 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9 or less, or 8 or less.
  • R 1 and R 2 each independently represent a methyl group or a halogen atom, and R 3 represents a linear alkylene group having 2 or more carbon atoms.
  • R 4 represents a hydrogen atom or a halogen atom.
  • R 1 and R 2 represent a methyl group
  • R 3 represents a linear alkylene group having 2 or more carbon atoms
  • R 4 represents hydrogen.
  • R 1 and R 2 represent a methyl group
  • R 3 represents a linear alkylene group having 2 or more carbon atoms
  • R 4 represents hydrogen. Represents an atom.
  • the compound represented by the formula (1) may be a solid or a liquid at 25 ° C.
  • the viscosity of the compound represented by the formula (1) at 25 ° C. is 10 mPa ⁇ s or less, 5 mPa ⁇ s or less, or 1 mPa ⁇ s or less. It may be present, and may be 0.2 mPa ⁇ s or more.
  • the viscosity of the compound represented by the formula (1) at 25 ° C. is measured by a differential pressure type micro viscometer (for example, a differential pressure type micro viscometer Microbisque manufactured by RheoSense (for example, low viscosity sensor cartridge HA01-01 is applied)). Will be done.
  • the content of the compound represented by the formula (1) is 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 1 based on the total amount of the electrolytic solution. It may be 50% by mass or more, 2% by mass or more, 3% by mass or more, 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, 50% by mass or less, 40% by mass or less, 30. It may be 0% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 9% by mass or less, 8% by mass or less, 7% by mass or less, 6% by mass or less, or 5% by mass or less.
  • the lithium salt examples include a lithium salt (first lithium salt) that functions as an electrolyte salt, a lithium salt of a cyclic compound having a ring containing a boron atom or a phosphorus atom (second lithium salt), a fluorine atom, and an oxygen atom. And a lithium salt of a compound having a phosphorus atom (third lithium salt) and the like.
  • the lithium salt corresponding to the second lithium salt or the third lithium salt is not included in the first lithium salt. Further, the lithium salt corresponding to the second lithium salt is not included in the third lithium salt.
  • the first lithium salt is, for example, LiPF 6 , LiBF 4 , LiClO 4 , LiB (C 6 H 5 ) 4 , LiCH 3 SO 3 , CF 3 SO 2 OLi, LiN (SO 2 F) 2 (Li [FSI]]. , Lithium bisfluorosulfonylimide), LiN (SO 2 CF 3 ) 2 (Li [TFSI], lithium bistrifluoromethanesulfonylimide), and LiN (SO 2 CF 2 CF 3 ) 2 at least selected from the group. May be.
  • the lithium salt preferably contains LiPF 6 from the viewpoint of further excellent solubility in a solvent, charge / discharge characteristics of a secondary battery, output characteristics, cycle characteristics and the like.
  • the concentration of the first lithium salt is preferably 0.5 mol / L or more, more preferably 0.7 mol / L or more, still more preferably 0.8 mol, based on the total amount of the non-aqueous solvent from the viewpoint of excellent charge / discharge characteristics.
  • / L or more preferably 1.5 mol / L or less, more preferably 1.3 mol / L or less, still more preferably 1.2 mol / L or less.
  • the second lithium salt may be, for example, a lithium salt represented by the following formula (2).
  • M represents a boron atom or a phosphorus atom
  • X represents a halogen atom or a fluoroalkyl group
  • p represents an integer of 1 to 3.
  • P is preferably 2.
  • the number of carbon atoms of the fluoroalkyl group represented by X may be, for example, 1 to 4.
  • X is preferably a fluorine atom or a trifluoromethyl group, and more preferably a fluorine atom.
  • the second lithium salt include a lithium salt represented by the following formula.
  • the content of the second lithium salt is 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass based on the total amount of the electrolytic solution. % Or more, and may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass or less.
  • the third lithium salt include a lithium salt represented by the following formula.
  • the content of the third lithium salt is 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass based on the total amount of the electrolytic solution. % Or more, and may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass or less.
  • the lithium salt may contain any one of a first lithium salt, a second lithium salt, and a third lithium salt, and may contain two or more kinds.
  • the lithium salt may contain, for example, a first lithium salt and a second lithium salt, and may contain a first lithium salt and a third lithium salt.
  • a first lithium salt, a second lithium salt, and a third lithium salt may contain any one of a first lithium salt, a second lithium salt, and a third lithium salt, and may contain two or more kinds.
  • the lithium salt may contain, for example, a first lithium salt and a second lithium salt, and may contain a first lithium salt and a third lithium salt.
  • a first lithium salt, a second lithium salt, and a third lithium salt may contain any one of a first lithium salt, a second lithium salt, and a third lithium salt.
  • the content of the second lithium salt and / or the third lithium salt is the first. 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, 20 parts by mass or less, based on 100 parts by mass of the total amount of the lithium salt, the second lithium salt and the third lithium salt. It may be 15 parts by mass or less, or 10 parts by mass or less.
  • the non-aqueous solvent is a non-aqueous solvent that can dissolve the lithium salt.
  • the non-aqueous solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ⁇ -butyl lactone, acetonitrile, 1,2-dimethoxyethane, dimethoxymethane, tetrahydrofuran, dioxolane, methylene chloride, methyl acetate and the like. May be.
  • the non-aqueous solvent may be one of these alone or a mixture of two or more thereof, and is preferably a mixture of two or more.
  • the content of the non-aqueous solvent may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, and 99% by mass or less, based on the total amount of the electrolytic solution. It may be there.
  • the electrolytic solution described above can improve the performance of the electrochemical device by containing the compound represented by the formula (1). Specifically, for example, by containing the compound represented by the formula (1) in the electrolytic solution, the viscosity of the electrolytic solution can be reduced. This can improve the diffusion rate of the lithium salt cations (Li + ) in the electrolyte, which in turn can improve the rate characteristics of the electrochemical device. In addition, by lowering the viscosity of the electrolytic solution, improvement of the permeability of the electrolytic solution to the high-density electrode and suppression of foaming of the electrolytic solution can be achieved.
  • the Si—F bond in the compound represented by the formula (1) traps the anion of the lithium salt (for example, PF6- ) to improve the dissociability of the lithium salt, resulting in an electrochemical device.
  • the interfacial charge transfer resistance in (secondary battery) can be reduced.
  • the Si—F bond in the compound represented by the formula (1) can stabilize the anion of the lithium salt and suppress the decomposition of the anion on the electrode.
  • the compound represented by the formula (1) since the compound represented by the formula (1) has excellent electrochemical stability, the above-mentioned effects are obtained as compared with the conventional film-forming additives such as vinylene carbonate and fluoroethylene carbonate. It can be exerted over a long period of time.
  • the electrolytic solution may further contain an additive in addition to the compound represented by the formula (1), the lithium salt and the non-aqueous solvent. It is expected that the effect of the compound represented by the above-mentioned formula (1) will be more remarkably obtained by further containing the additive in the electrolytic solution.
  • the additive in the present specification means a component other than the compound represented by the formula (1), a lithium salt and a non-aqueous solvent, and the content thereof is 10% by mass or less based on the total amount of the electrolytic solution. do.
  • the additive may contain a cyclic compound having a carbon-carbon double bond.
  • the cyclic compound having a carbon-carbon double bond may be, for example, a cyclic carbonate having a carbon-carbon double bond.
  • the two carbons constituting the ring may form a double bond.
  • Examples of the cyclic carbonate having a carbon-carbon double bond include vinylene carbonate, methylvinylene carbonate, dimethylvinylene carbonate (4,5-dimethylvinylene carbonate), ethylvinylene carbonate (4,5-diethylvinylene carbonate), and diethyl. Vinylene carbonate can be mentioned.
  • the cyclic carbonate having a carbon-carbon double bond is preferably vinylene carbonate from the viewpoint of further improving the performance of the electrochemical device.
  • the content of the cyclic compound having a carbon-carbon double bond is 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, based on the total amount of the electrolytic solution. Alternatively, it may be 0.1% by mass or more, and may be 10% by mass or less, 5% by mass or less, 3% by mass or less, or 2% by mass or less.
  • the additive may contain a cyclic compound having a fluorine atom.
  • the cyclic compound having a fluorine atom may be, for example, a cyclic carbonate having a fluorine atom.
  • the cyclic carbonate having a fluorine atom is a cyclic carbonate having a fluoro group.
  • Examples of the cyclic carbonate having a fluorine atom include 4-fluoro-1,3-dioxolane-2-one (fluoroethylene carbonate; FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1, Examples thereof include 1,2-trifluoroethylene carbonate and 1,1,2,2-tetrafluoroethylene carbonate.
  • Cyclic carbonate having a fluorine atom is preferably 4-fluoro-1,3-dioxolane-2-one (fluoroethylene carbonate; FEC) from the viewpoint of suppressing side reactions when a stable film is formed on the negative electrode. Is.
  • the content of the cyclic compound having a fluorine atom is 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, or 0.1 based on the total amount of the electrolytic solution. It may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass or less.
  • the additive may include a cyclic compound having a sulfur atom.
  • the cyclic compound having a sulfur atom may be, for example, a cyclic sulfonic acid ester compound (also referred to as a sultone compound).
  • the cyclic sulfonic acid ester compound is a compound having a ring containing an —OSO2- group. Cyclic sulfonic acid ester compounds have a ring containing one or two —OSO2-groups.
  • the cyclic sulfonic acid ester compound having a ring containing -OSO 2 -group may be, for example, a compound represented by the following formula (X) (monosulfonic acid ester).
  • a 1 represents an alkylene group having 3 to 5 carbon atoms or an alkenylene group having 3 to 5 carbon atoms
  • the hydrogen atom in the alkylene group and the alkaneylene group is an alkyl group, a cycloalkyl group or an aryl. It may be substituted with a group or a fluoro group.
  • the number of carbon atoms of the alkyl group may be, for example, 1 to 12.
  • the cycloalkyl group may have, for example, 3 to 6 carbon atoms.
  • the aryl group may have, for example, 6 to 12 carbon atoms.
  • a 1 is preferably an alkylene group having 3 carbon atoms or an alkenylene group having 3 carbon atoms. That is, the monosulfonic acid ester is preferably a compound represented by the following formula (X-1) or formula (X-2).
  • R 11 to R 20 independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a fluoro group.
  • the carbon number of the alkyl group, the cycloalkyl group and the aryl group represented by R 11 to R 20 is the same as the carbon number of the alkyl group, the cycloalkyl group and the aryl group described in the formula (X), respectively.
  • R 11 to R 20 are preferably hydrogen atoms.
  • the monosulfonic acid ester examples include 1,3-propane sultone, 1,4-butane sultone, 2,4-butane sultone, 1,3-propensultone, 1,4-butensultone, and 1-methyl-1,3-propane. Examples thereof include sultone, 3-methyl-1,3-propane sultone, 1-fluoro-1,3-propane sultone, and 3-fluoro-1,3-propane sultone. From the viewpoint of further improving the performance of the electrochemical device, the monosulfonic acid ester is preferably 1,3-propane sultone (in the formula (X-1), all of R 11 to R 16 are hydrogen atoms. A compound) or 1-propen-1,3-sultone (a compound in which all of R 17 to R 20 are hydrogen atoms in the formula (X-2)).
  • the cyclic sulfonic acid ester compound having a ring containing two -OSO 2 -groups may be, for example, a compound represented by the following formula (X-3) (disulfonic acid ester).
  • B 1 and B 2 independently represent an alkylene group having 1 to 5 carbon atoms or an alkaneylene group having 1 to 5 carbon atoms, and the hydrogen atom in the alkylene group and the alkaneylene group is an alkyl group or a cyclo. It may be substituted with an alkyl group, an aryl group, or a fluoro group.
  • B 1 and B 2 are preferably unsubstituted alkylene groups having 1 or 2 carbon atoms.
  • the disulfonic acid ester include methylenemethane disulfonic acid ester and ethylene methanedisulfonic acid ester.
  • the cyclic compound having a sulfur atom may be, for example, a compound represented by the formula (Y) or a compound represented by the formula (Z).
  • a 2 and A 3 independently represent an alkylene group having 3 to 5 carbon atoms or an alkenylene group having 3 to 5 carbon atoms, and hydrogen in the alkylene group and the alkaneylene group.
  • the atom may be substituted with an alkyl group, a cycloalkyl group or an aryl group.
  • the carbon number of the alkyl group, the cycloalkyl group and the aryl group in A 2 and A 3 is the same as the carbon number of the alkyl group, the cycloalkyl group and the aryl group described in the formula (X), respectively.
  • Examples of the compound represented by the formula (Y) include sulfolane, 2-methylsulfolane, 3-methylsulfolane, 2-ethylsulfolane, 3-ethylsulfolane, 2,4-dimethylsulfolane, 2-phenylsulfolane, 3-. Included are phenylsulfolanes, sulfolanes, and 3-methylsulfolanes.
  • the compound represented by the formula (Y) is preferably a sulfolane from the viewpoint of further improving the performance of the electrochemical device.
  • Examples of the compound represented by the formula (Z) include ethylene sulphite, propylene sulphite, butylene sulphite, vinylen sulphite, and phenylethylene sulphite.
  • the compound represented by the formula (Z) is preferably ethylene sulfate from the viewpoint of further improving the performance of the electrochemical device.
  • the content of the cyclic compound having a sulfur atom is 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, or 0.1 based on the total amount of the electrolytic solution. It may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass or less.
  • the additive may contain a nitrile compound.
  • the nitrile compound is a compound having at least one cyano group (nitrile group).
  • the nitrile compound may have one or more cyano groups and may have two or three cyano groups.
  • Examples of the nitrile compound having one cyano group include butyronitrile, valeronitrile, and n-heptanenitrile.
  • Examples of the nitrile compound having two cyano groups include succinonitrile, glutarine nitrile, adiponitrile, pimeronitrile, and suberonitrile.
  • Examples of the nitrile compound having three cyano groups include 1,2,3-propanetricarbonitrile and 1,3,5-pentanetricarbonitrile.
  • the nitrile compound preferably has two or more cyano groups and a carbon atom in the cyano group from the viewpoint that a stable film is formed on the positive electrode or the negative electrode and the expansion of the battery due to the decomposition of the electrolytic solution can be suppressed. It is a nitrile compound having 2 or more carbon atoms excluding.
  • the nitrile compound is more preferably a compound having two or three cyano groups and having two or more carbon atoms excluding carbon atoms in the cyano group.
  • the nitrile compound is more preferably succinonitrile, glutalnitrile, adiponitrile, pimeronitrile, suberonitrile, 1,2,3-propanetricarbonitrile, or 1,3,5-pentanetricarbonitrile.
  • the content of the nitrile compound is 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more based on the total amount of the electrolytic solution. It may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass or less.
  • the content of the additive (when the electrolytic solution contains two or more kinds of additives, the total content thereof) is 0.001% by mass or more, 0.005% by mass or more, based on the total amount of the electrolytic solution. It may be 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more, and may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass. It may be as follows.
  • the viscosity of the electrolytic solution at 25 ° C. may be 20 mPa ⁇ s or less, 10 mPa ⁇ s or less, or 5 mPa ⁇ s or less, and may be 0.5 mPa ⁇ s or more.
  • the viscosity of the electrolytic solution at 25 ° C. is measured by a differential pressure type micro viscometer (for example, a differential pressure type micro viscometer Microbisque manufactured by RheoSense (for example, low viscosity sensor cartridge HA01-01 is applied)).
  • the method for manufacturing the non-aqueous electrolyte secondary battery 1 includes a first step of obtaining a positive electrode 6, a second step of obtaining a negative electrode 8, and a third step of accommodating the electrode group 2 in the battery exterior body 3. A fourth step of injecting the electrolytic solution into the battery exterior 3 is provided.
  • the material used for the positive electrode mixture layer 10 is dispersed in a dispersion medium using a kneader, a disperser, or the like to obtain a slurry-like positive electrode mixture, and then this positive electrode mixture is used by the doctor blade method.
  • the positive electrode 6 is obtained by applying it on the positive electrode current collector 9 by a dipping method, a spray method, or the like, and then volatilizing the dispersion medium. After volatilizing the dispersion medium, a compression molding step by a roll press may be provided, if necessary.
  • the positive electrode mixture layer 10 may be formed as a multilayer structure positive electrode mixture layer by performing the above-mentioned steps from application of the positive electrode mixture to volatilization of the dispersion medium a plurality of times.
  • the dispersion medium may be water, 1-methyl-2-pyrrolidone (hereinafter, also referred to as NMP) or the like.
  • the second step may be the same as the first step described above, and the method of forming the negative electrode mixture layer 12 on the negative electrode current collector 11 may be the same method as the first step described above. ..
  • the separator 7 is sandwiched between the produced positive electrode 6 and the negative electrode 8 to form the electrode group 2.
  • the electrode group 2 is housed in the battery exterior body 3.
  • the electrolytic solution is injected into the battery exterior body 3.
  • the electrolytic solution can be prepared, for example, by first dissolving the lithium salt in a non-aqueous solvent and then further dissolving other materials in the non-aqueous solvent.
  • the electrochemical device may be a capacitor. Similar to the non-aqueous electrolytic solution secondary battery 1 described above, the capacitor may include an electrode group composed of a positive electrode, a negative electrode, and a separator, and a bag-shaped battery exterior body accommodating the electrode group. The details of each component in the capacitor may be the same as those of the non-aqueous electrolyte secondary battery 1.
  • Example 2 An electrolytic solution was prepared in the same manner as in Example 1 except that the content of the compound represented by the formula (A) was changed to 5% by mass (corresponding to 0.33 mol with respect to 1 mol of LiPF 6 ) based on the total amount of the electrolytic solution. bottom.
  • the viscosity of the electrolytic solution was reduced by containing the compound represented by the formula (1) in the electrolytic solution.
  • This can improve the diffusion rate of the lithium salt cations (Li + ) in the electrolyte, which in turn can improve the rate characteristics of the electrochemical device. That is, the performance of the electrochemical device can be improved by containing the compound represented by the formula (1) in the electrolytic solution.
  • Non-aqueous electrolyte secondary battery electrochemical device
  • 6 Positive electrode
  • 7 Separator
  • 8 Negative electrode

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PCT/JP2020/037170 2020-09-30 2020-09-30 電解液及び電気化学デバイス WO2022070312A1 (ja)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007012595A (ja) * 2005-05-30 2007-01-18 Denso Corp 非水電解液及び該電解液を用いた非水電解液二次電池
WO2012066879A1 (ja) * 2010-11-16 2012-05-24 株式会社Adeka 非水電解液二次電池
JP2015195135A (ja) * 2014-03-31 2015-11-05 三井化学株式会社 電池用非水電解液、及びリチウム二次電池
JP2018147899A (ja) * 2018-06-27 2018-09-20 オートモーティブエナジーサプライ株式会社 リチウムイオン二次電池

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007012595A (ja) * 2005-05-30 2007-01-18 Denso Corp 非水電解液及び該電解液を用いた非水電解液二次電池
WO2012066879A1 (ja) * 2010-11-16 2012-05-24 株式会社Adeka 非水電解液二次電池
JP2012109091A (ja) * 2010-11-16 2012-06-07 Adeka Corp 非水電解液二次電池
JP2015195135A (ja) * 2014-03-31 2015-11-05 三井化学株式会社 電池用非水電解液、及びリチウム二次電池
JP2018147899A (ja) * 2018-06-27 2018-09-20 オートモーティブエナジーサプライ株式会社 リチウムイオン二次電池

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