Classifications

• • 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
  • H01M10/052—Li-accumulators
• • 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
• • 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
  • H01M10/0568—Liquid materials characterised by the solutes
• • 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

• the present disclosure relates to a non-aqueous electrolytic solution and a lithium ion secondary battery in which the non-aqueous electrolytic solution is used.
• Patent Document 1 proposes an electrode for a secondary battery containing a radical material containing a conductive material mixed with a conductive material, and a secondary battery including the electrode.
• Patent Document 2 proposes an active material subjected to spin labeling treatment using a spin labeling agent containing a nitroxide radical compound as a radical material, and a secondary battery including an electrode layer containing the active material.
• Patent Document 3 proposes an electrode active material containing a polymer having an azaanthraquinone skeleton as a radical material and a secondary battery including an electrode containing the electrode active material.
• the radical material itself does not have conductivity, when the radical material is put into the active material, the conductivity of the electrode is lowered and the battery performance is deteriorated. Therefore, a manufacturing process of compounding a radical material and a conductive material is required.
• the present disclosure has been made in view of this point, and is a lithium ion secondary battery containing a radical material, which does not reduce the energy density per volume as a battery, and which facilitates the battery manufacturing process, and the lithium ion secondary battery. It is an object of the present invention to provide a non-aqueous electrolyte solution used for a secondary battery.
• the present disclosure is as follows. -The non-aqueous electrolytic solution of the present disclosure is characterized by containing a lithium salt as an electrolyte salt, an electrolytic solution solvent, and a compound having a nitroxy radical group. Further, the non-aqueous electrolytic solution of the present disclosure contains a lithium salt as an electrolyte salt, an electrolytic solution solvent, and a compound having a nitroxy radical group, and the lithium salt is represented by the following general formula (1).
• LiN (XSO 2 ) (FSO 2 ) (1) (In the general formula (1), X represents a fluorine atom, an alkyl group having 1 to 6 carbon atoms or a fluoroalkyl group having 1 to 6 carbon atoms.) -The lithium ion secondary battery of the present disclosure uses the above-mentioned non-aqueous electrolytic solution.
• a lithium ion secondary battery containing a radical material, having no decrease in energy density per volume as a battery, and facilitating a battery manufacturing process, and a non-aqueous electrolyte solution used in the lithium ion secondary battery. Can be provided.
• the non-aqueous electrolytic solution according to the present embodiment contains a lithium salt as an electrolyte salt, an electrolytic solution solvent, and a compound having a nitroxy radical group.
• This non-aqueous electrolytic solution is particularly preferably used for a lithium ion secondary battery among the non-aqueous electrolytic solution secondary batteries.
• the non-aqueous electrolyte solution according to this embodiment contains a lithium salt as an electrolyte salt.
• the lithium salt include a sulfonylimide compound represented by the general formula (1): LiN (XSO 2 ) (FSO 2 ) (hereinafter, also simply referred to as “sulfonylimide compound”).
• X represents a fluorine atom, an alkyl group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms.
• Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group and a hexyl group.
• Examples of the alkyl groups having 1 to 6 carbon atoms a linear or branched alkyl group having 1 to 6 carbon atoms is preferable, and a linear alkyl group having 1 to 6 carbon atoms is more preferable.
• Examples of the fluoroalkyl group having 1 to 6 carbon atoms include those in which a part or all of the hydrogen atoms of the alkyl group having 1 to 6 carbon atoms are replaced with fluorine atoms.
• fluoroalkyl group having 1 to 6 carbon atoms include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, a pentafluoroethyl group and the like.
• substituent X a fluorine atom, a trifluoromethyl group and a pentafluoroethyl group are preferable.
• the sulfonylimide compound examples include lithium bis (fluorosulfonyl) imide (hereinafter also referred to as "LiFSI"), lithium (fluorosulfonyl) (methylsulfonyl) imide, lithium (fluorosulfonyl) (ethylsulfonyl) imide, and lithium (fluoro). Examples thereof include sulfonyl) (trifluoromethylsulfonyl) imide and lithium (fluorosulfonyl) (pentafluoroethylsulfonyl) imide.
• the sulfonylimide compounds may be used alone or in combination of two or more.
• the sulfonylimide compound a commercially available product may be used, or a compound obtained by synthesizing by a conventionally known method may be used.
• the sulfonylimide compounds lithium bis (fluorosulfonyl) imide, lithium (fluorosulfonyl) (trifluoromethylsulfonyl) imide, and lithium (fluorosulfonyl) (pentafluoroethylsulfonyl) imide are preferable, and lithium bis (fluorosulfonyl). Imides are more preferred.
• the non-aqueous electrolyte solution may contain other electrolyte salts different from the sulfonylimide compound.
• electrolyte salts trifluoromethanesulfonic acid ion (CF 3 SO 3 -), hexafluorophosphate ion (PF 6 -), perchlorate ion (ClO 4 -), tetrafluoroborate ion (BF 4 -) , hexafluoroarsenate ion (AsF 6 -), tetracyanoquinodimethane borate ion ([B (CN) 4] -), tetrachloro aluminum ion (AlCl 4 -), tricyanomethide ion (C [(CN) 3] - ), Disianamide ion (N [(CN) 2 ] - ), Bis (trifluoromethanesulfonyl) imide ion (N [(SO 2 CF 3 ) 2
• electrolyte salts may be used alone or in combination of two or more.
• a compound represented by the general formula (2) hereinafter, also referred to as “fluorophosphate compound”
• a compound represented by the general formula (3) hereinafter, also referred to as “fluoroboric acid compound”.
• fluorophosphate compound a compound represented by the general formula (2)
• fluoroboric acid compound hereinafter, also referred to as “fluoroboric acid compound”.
• lithium hexafluoroarsenate are preferred.
• Fluorophosphate compound represented by the general formula (2) represented by LiPF a (C m F 2m + 1) 6-a (0 ⁇ a ⁇ 6,1 ⁇ m ⁇ 4).
• the fluorophosphate compound include LiPF 6 , LiPF 3 (CF 3 ) 3 , LiPF 3 (C 2 F 5 ) 3 , LiPF 3 (C 3 F 7 ) 3 , LiPF 3 (C 4 F 9 ) 3, and the like. Be done.
• the fluorophosphoric acid compounds may be used alone or in combination of two or more. Among the fluorophosphate compounds, LiPF 6 and LiPF 3 (C 2 F 5 ) 3 are preferable, and LiPF 6 is more preferable.
• the fluoroboric acid compound is represented by the general formula (3): LiBF b (C n F 2n + 1 ) 4-b (0 ⁇ b ⁇ 4, 1 ⁇ n ⁇ 4).
• Examples of the fluoroboric acid compound include LiBF 4 , LiBF (CF 3 ) 3 , LiBF (C 2 F 5 ) 3 , LiBF (C 3 F 7 ) 3, and the like.
• the fluoroboric acid compounds may be used alone or in combination of two or more. Among the fluoroboric acid compounds, LiBF 4 and LiBF (CF 3 ) 3 are preferable, and LiBF 4 is more preferable.
• an electrolyte salt having a mixed salt composition containing the sulfonylimide compound and other electrolyte salts is preferable to the electrolyte salt having a single salt composition of the sulfonylimide compound, and the sulfonylimide compound and the fluorophosphate compound are contained.
• An electrolyte salt having a mixed salt composition is more preferable, and an electrolyte salt having a mixed salt composition containing LiFSI and LiPF 6 is even more preferable.
• the concentration of the sulfonylimide compound in the non-aqueous electrolyte solution is preferably 0.01 mol / L or more, more preferably 0., from the viewpoint of reducing the interfacial resistance and DC resistance of the battery, improving the high temperature durability and the charge / discharge cycle characteristics. It is 05 mol / L or more, more preferably 0.1 mol / L or more, still more preferably 0.2 mol / L or more, and even more preferably 0.5 mol / L or more.
• the concentration is preferably 1.5 mol / L or less, more preferably 1.2 mol / L or less, still more preferably 1 mol / L or less, from the viewpoint of suppressing corrosion of the positive electrode current collector.
• each concentration of the other electrolyte salt in the non-aqueous electrolyte solution reduces the interface resistance and DC resistance of the battery, and is durable at high temperature.
• it is preferably 0.1 mol / L or more, more preferably 0.2 mol / L or more, still more preferably 0.5 mol / L or more.
• the concentration is preferably 1.5 mol / L or less, more preferably 1.2 mol / L or less, still more preferably 1 mol / L or less, from the viewpoint of suppressing corrosion of the positive electrode current collector.
• the total concentration of electrolyte salts in the non-aqueous electrolyte solution is preferably 0.1 mol / L or more, more preferably 0, from the viewpoint of reducing the interfacial resistance and DC resistance of the battery, improving the high temperature durability and the charge / discharge cycle characteristics. .2 mol / L or more, more preferably 0.5 mol / L or more, still more preferably 1 mol / L or more. Further, the concentration is preferably 3 mol / L or less, more preferably 2.4 mol / L or less, still more preferably 2 mol / L or less, still more preferably 1. It is 5 mol / L or less, and even more preferably 1.2 mol / L or less.
• the content of the sulfonylimide compound in the non-aqueous electrolyte solution is 100 mol% in total of the electrolyte salts contained in the non-aqueous electrolyte solution from the viewpoint of reducing the interface resistance and DC resistance of the battery, improving the high temperature durability and the charge / discharge cycle characteristics.
• 10 mol% or more is preferable, 20 mol% or more is more preferable, and 30 mol% or more is further preferable.
• the most preferable range is 50 mol% or more.
• Sulfonylimide compounds Other electrolyte salts are preferably 1:15 or more, more preferably 1:10 or more, even more preferably 1: 5 or more, still more preferably 1: 2 or more, even more preferably 1: 1 or more. Is.
• the non-aqueous electrolytic solution contains an electrolytic solution solvent.
• the electrolytic solution solvent is not particularly limited as long as it can dissolve and disperse the electrolyte salt.
• Examples of the electrolytic solution solvent include a non-aqueous solvent, a polymer used in place of the electrolytic solution solvent, a medium such as a polymer gel, and the like. , Any solvent commonly used for batteries can be used.
• non-aqueous solvent a solvent having a large dielectric constant, high solubility of the electrolyte salt, a boiling point of 60 ° C. or higher, and a wide electrochemical stable range is preferable. More preferably, it is an organic solvent having a low water content. Examples of such an organic solvent include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, tetrahydrofuran, 2-methyl tetrahydrofuran, 2,6-dimethyl tetrahydrofuran, tetrahydropyran, crown ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and the like.
• Ether-based solvents such as 1,4-dioxane and 1,3-dioxolane; chain carbonate-based solvents such as dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, diphenyl carbonate and methylphenyl carbonate; ethylene carbonate, propylene carbonate , 2,3-Dimethylethylene carbonate, 1,2-butylene carbonate, erythritan carbonate and other saturated cyclic carbonate solvents; vinylene carbonate, methylvinylene carbonate, ethylvinylene carbonate, 2-vinylethylene carbonate and phenylethylene carbonate and the like.
• Cyclic carbonate-based solvent having unsaturated bond Fluorine-containing cyclic carbonate-based solvent such as fluoroethylene carbonate, 4,5-difluoroethylene carbonate and trifluoropropylene carbonate; aromatic carboxylic acid such as methyl benzoate and ethyl benzoate Ester solvent; lactone solvent such as ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -valerolactone; phosphate ester solvent such as trimethyl phosphate, ethyldimethyl phosphate, diethylmethyl phosphate, triethyl phosphate; acetonitrile, Nitrile-based solvents such as propionitrile, methoxypropionitrile, glutaronitrile, adiponitrile, 2-methylglutaronitrile, valeronitrile, butyronitrile, isobutyronitrile; dimethylsulfone, ethylmethylsulfone, diethylsulfone
• carbonate-based solvents such as chain carbonate-based solvents and cyclic carbonate-based solvents, lactone-based solvents, and ether-based solvents are preferable, and dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate are preferable.
• ⁇ -Butyrolactone, ⁇ -Valerolactone and the like are more preferable, and carbonate solvents such as dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, ethylene carbonate and propylene carbonate are further preferable.
• the following method may be adopted. That is, a method in which a solution obtained by dissolving an electrolyte salt in a solvent is dropped onto a polymer formed by a conventionally known method to impregnate and support the electrolyte salt and a non-aqueous solvent; the polymer and the electrolyte at a temperature equal to or higher than the melting point of the polymer.
• a method in which a salt is melted and mixed, a film is formed, and a solvent is impregnated therein (hereinafter, gel electrolyte); a non-aqueous electrolyte solution in which an electrolyte salt is previously dissolved in an organic solvent and a polymer are mixed, and then this is performed.
• gel electrolyte a non-aqueous electrolyte solution in which an electrolyte salt is previously dissolved in an organic solvent and a polymer are mixed, and then this is performed.
• a method of forming a film by a casting method or a coating method to volatilize an organic solvent a method of melting a polymer and an electrolyte salt at a temperature equal to or higher than the melting point of the polymer, and mixing and molding (intrinsic polymer electrolyte); etc. ..
• a homopolymer or a copolymer of an epoxy compound ethylene oxide, propylene oxide, butylene oxide, allylglycidyl ether, etc.
• a polyether such as polyethylene oxide (PEO), polypropylene oxide, etc.
• PMMA methacrylic polymers
• PAN polymethylmethacrylate
• PVdF polyvinylidene fluoride
• PVdF polyvinylidene fluoride-hexafluoropropylene and other fluoropolymers
• co-polymers thereof examples include polymers. These polymers may be used alone or in combination of two or more.
• the non-aqueous electrolyte solution further contains a compound having a nitroxy radical group as a radical material.
• the compound having a nitroxy radical group is not contained in the electrode, but is contained in the non-aqueous electrolytic solution. Therefore, it is not necessary to further add an insoluble material into the electrode. Therefore, in the battery using the non-aqueous electrolytic solution, there is no inconvenience that the ratio of the active material in the electrode is lowered and the energy density per volume of the battery is lowered accordingly.
• a battery using a non-aqueous electrolytic solution in which a compound having a nitroxy radical group is dissolved improves its battery performance. More specifically, the increase in the interfacial resistance of the battery using this non-aqueous electrolyte solution at 25 ° C. and -30 ° C. is suppressed, and the direct current resistance (DCR) of the battery is reduced accordingly, and the high temperature durability performance and the high temperature durability performance and Deterioration of cycle characteristics is suppressed.
• DCR direct current resistance
• the non-aqueous electrolytic solution according to the present embodiment can be obtained only by dissolving the compound having a nitroxy radical group in the non-aqueous electrolytic solution containing the lithium salt and the electrolytic solution solvent. Therefore, the manufacturing process of the battery using the non-aqueous electrolytic solution is easy.
• Examples of the compound having a nitroxy radical group include 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and 4-methacryloyloxy-2,2,6,6-tetramethylpiperidin-1-.
• nitrosodisulfonate examples include alkali metal salts of nitrosodisulfonic acid.
• alkali metal salt of nitrosodisulfonic acid examples include potassium nitrosodisulfonate, disodium 1-nitroso-2-naphthol-3,6-disulfonate and the like. These compounds having a nitroxy radical group may be used alone or in combination of two or more.
• a compound having a nitroxyl radical group having a sulfonyl group (nitrosodisulfonic acid and / or a salt) is preferable, a nitrosodisulfonate is more preferable, and an alkali metal salt of nitrosodisulfonic acid is preferable. Even more preferred, potassium nitrosodisulfonate is even more preferred.
• the content of the compound having a nitroxy radical group in the non-aqueous electrolytic solution is 100% by mass of the non-aqueous electrolytic solution from the viewpoint of reducing the interfacial resistance and DC resistance of the battery, improving the high temperature durability and the charge / discharge cycle characteristics. It is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more.
• the content of the compound having a nitroxy radical group in the non-aqueous electrolyte solution is 100 mass by mass of the non-aqueous electrolyte solution from the viewpoint of reducing the interfacial resistance and DC resistance of the battery, improving the high temperature durability and the charge / discharge cycle characteristics. In%, it is preferably 3% by mass or less, and more preferably 1% by mass or less.
• 100% by mass of the non-aqueous electrolytic solution is included in the non-aqueous electrolytic solution such as an electrolyte salt, an electrolytic solution solvent, a compound having a nitroxy radical group, and other components used as necessary. Means the sum of all the ingredients.
• the non-aqueous electrolyte solution may contain additives for the purpose of improving various characteristics of the lithium ion secondary battery.
• Additives include succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride, diglycolic anhydride, cyclohexanedicarboxylic acid anhydride, cyclopentanetetracarboxylic dianhydride, and phenyl.
• Carboxylanhydrides such as succinic anhydride; ethylenesulfite, 1,3-propanesulton, 1,4-butanesulton, methyl methanesulfonate, bushalphane, sulfolane, sulfolene, dimethylsulfone, tetramethylthium monosulfide, trimethylene Sulfur-containing compounds such as glycol sulfate ester; 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone, N-methylsuccinimide, etc.
• succinic anhydride ethylenesulfite, 1,3-propanesulton, 1,4-butanesulton, methyl methanesulfonate, bushalphane, sulfolane, sulfolene, dimethylsulfone, tetramethylthium monosulfide, trimethylene Sulfur-
• Nitrogen-containing compounds such as monofluorophosphate and difluorophosphate; saturated hydrocarbon compounds such as heptane, octane and cycloheptane; vinylene carbonate (VC), vinylethylene carbonate (VEC), methylvinylene carbonate Cyclic carbonate having an unsaturated bond such as (MVC), ethylvinylene carbonate (EVC); carbonate compounds such as fluoroethylene carbonate (FEC), trifluoropropylene carbonate, phenylethylene carbonate and erythritan carbonate; lithium bisoxalate bora -Alkali metal salt of oxalatoborate such as LiBOB; sulfamic acid (amide sulfate, H 3 NSO 3 ); sulfamate (alkali metal salt such as lithium salt, sodium salt, potassium salt; calcium salt, strontium salt) , Alkaline earth metal salts such as barium salt; other metal salts such as manganes, sodium salt
• H 3 NSO 3 and its salt (hereinafter, also referred to as “sulfamic acid compound”) are preferable, and H 3 NSO 3 and its lithium salt are more preferable, from the viewpoint of further reducing the interfacial resistance of the battery.
• H 3 NSO 3 and LiH 2 NSO 3 are more preferred.
• LiH 2 NSO 3 can be produced by the method described in the following Examples.
• the additive is preferably used in the range of 0.1% by mass or more and 10% by mass or less, and more preferably 0.2% by mass or more and 8% by mass or less in 100% by mass of the non-aqueous electrolytic solution. It is more preferable to use it in the range of 0.3% by mass or more and 5% by mass or less.
• the viscosity of the non-aqueous electrolyte solution may increase and the conductivity may decrease.
• the amount of the sulfamic acid compound added to the non-aqueous electrolyte solution is preferably 0.1% by mass or more, more preferably 0.2% by mass, based on 100% by mass of the non-aqueous electrolyte solution, from the viewpoint of further reducing the interfacial resistance of the battery. It is by mass% or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more.
• the amount of the sulfamic acid compound added to the non-aqueous electrolytic solution is preferably 1 mass in 100% by mass of the non-aqueous electrolytic solution from the viewpoint of reducing the amount of insoluble particles of the sulfamic acid compound remaining in the non-aqueous electrolytic solution. % Or less, more preferably 0.8% by mass or less.
• the non-aqueous electrolyte solution is composed of each component such as a lithium salt, an electrolyte solution solvent, a compound having a nitroxy radical group,, if necessary, another electrolyte salt, various additives, and the like.
• the non-aqueous electrolytic solution can be prepared, for example, by mixing each of these components in a predetermined composition ratio (hereinafter, also referred to as “non-aqueous electrolytic solution (A)”).
• the solution in which each component is mixed may be left with stirring for, for example, 0.5 to 2 days.
• the non-aqueous electrolytic solution (A) may further contain other additives from the viewpoint of further improving the effect of adding the compound having a nitroxy radical group.
• fluorosulfonic acid (HFSO 3 ) which is an impurity (acid) derived from the sulfonylimide compound contained in the non-aqueous electrolytic solution (A)
• HFSO 3 fluorosulfonic acid
• the non-aqueous electrolytic solution (A) may further contain other additives from the viewpoint of further improving the effect of adding the compound having a nitroxy radical group.
• fluorosulfonic acid (HFSO 3 ) which is an impurity (acid) derived from the sulfonylimide compound contained in the non-aqueous electrolytic solution (A)
• HF hydrofluoric acid
• Li 2 CO 3 lithium carbonate
• Na 2 CO 3 sodium carbonate
• K 2 CO 3 potassium carbonate
• Rb 2 CO 3 rubidium carbonate
• Cs 2 CO 3 cesium carbonate
• beryllium carbonate (BeCO 3) magnesium carbonate
• MgCO 3 magnesium carbonate
• CaCO 3 calcium carbonate
• strontium carbonate (SrCO 3) alkaline earth metal carbonates such as barium carbonate (BaCO 3); alkali metal carbonates and the like
• Examples thereof include carbonates such as ammonium carbonate (NH 4 ) 2 CO 3 ); copper (II) carbonate (CuCO 3 ); iron (II) carbonate (FeCO 3 ); silver (I) carbonate (Ag 2 CO 3).
• These carbonates may be used alone or in combination of two or more.
• alkali metal carbonates and alkaline earth metal carbonates are preferable, alkali metal carbonates are more preferable, and lithium carbonate (Li 2 CO 3 ) is preferable from the viewpoint of reliably trapping HFSO 3 and / or HF.
• Sodium carbonate (Na 2 CO 3 ), potassium carbonate (K 2 CO 3 ), and cesium carbonate (Cs 2 CO 3 ) are even more preferred, and lithium carbonate (Li 2 CO 3 ) is even more preferred.
• the amount of carbonate added to the non-aqueous electrolyte solution (A) may be appropriately determined according to the amount of electrolyte salt used in the non-aqueous electrolyte solution, but from the viewpoint of reliably trapping HFSO 3 and / or HF.
• 100% by mass of the non-aqueous electrolyte solution (A) preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, still more preferably 0.5% by mass. % Or more.
• the amount of carbonate added to the non-aqueous electrolytic solution (A) is 100 mass by mass of the non-aqueous electrolytic solution (A) from the viewpoint of reducing the amount of carbonate insoluble particles remaining in the non-aqueous electrolytic solution (A). In%, it is preferably 1% by mass or less, more preferably 0.8% by mass or less.
• the sulfamic acid compound to the non-aqueous electrolytic solution (A) together with the carbonate.
• the effect of reducing the interfacial resistance of the battery is further improved.
• the total amount of carbonate and sulfamic acid compound added to the non-aqueous electrolyte solution (A) reliably traps HFSO 3 and / or HF, and from the viewpoint of further reducing the interfacial resistance of the battery, non-aqueous electrolysis In 100% by mass of the liquid (A), it is preferably 0.2% by mass or more, more preferably 0.4% by mass or more, and further preferably 0.6% by mass or more.
• the total amount of the carbonate and the sulfamic acid compound added to the non-aqueous electrolyte solution (A) is 100 mass by mass of the non-aqueous electrolyte solution (A) from the viewpoint of reducing the amount of insoluble particles remaining in the non-aqueous electrolyte solution (A). In%, it is preferably 2% by mass or less, more preferably 1.6% by mass or less, and further preferably 1.2% by mass or less.
• the non-aqueous electrolyte solution (A) is used to reliably trap HFSO 3 and / or HF in the carbonate or the like after adding a carbonate and, if necessary, a sulfamic acid compound (hereinafter referred to as “carbonate or the like”).
• carbonate or the like a sulfamic acid compound
• the sparingly soluble sulfamic acid compound is left to stand with stirring for 0.5 to 2 days, for example, in order to further dissolve it in the non-aqueous electrolyte solution (A).
• non-aqueous electrolytic solution (B) When a carbonate or the like is added to the non-aqueous electrolytic solution (A), it is preferable to filter the obtained solution (hereinafter, also referred to as “non-aqueous electrolytic solution (B)”). By filtering this non-aqueous electrolytic solution (B), carbonates and the like remaining in the non-aqueous electrolytic solution (B) are removed.
• the non-aqueous electrolytic solution (B) since carbonate and the like are insoluble in an organic solvent such as a carbonate solvent, they remain contained in the non-aqueous electrolytic solution (B) as an insoluble matter.
• the non-aqueous electrolyte solution (B) containing the fluorophosphate compound as the electrolyte salt the non-aqueous electrolyte solution continues to react with the HF derived from the fluorophosphate compound until carbon dioxide and the like disappear from the non-aqueous electrolyte solution (B).
• Moisture always remains in (B) the fluorophosphate compound is continuously decomposed, and gas such as carbon dioxide (CO 2) is continuously generated.
• insoluble particles such as carbonates remaining in the non-aqueous electrolyte solution (B) may cause the liquid injection device to malfunction, such as clogging of the high bar pump cylinder of the liquid injection device and deterioration of piston operation.
• the insoluble particles that cause the problem can be removed.
• the filtration method is not particularly limited as long as the carbonate or the like contained in the non-aqueous electrolyte solution (B) can be removed, and examples thereof include pressure filtration and suction filtration.
• the filter medium (filter) used is preferably a non-aqueous filter medium that targets an organic solvent or the like.
• the filter material is made of fluororesin such as PTFE; made of stainless steel fiber; made of polyethylene, ultra-high density polyethylene, made of polyolefin such as polypropylene; made of nylon; made of cellulose fiber; made of glass fiber; made of silica fiber; made of polycarbonate; made of cotton. Made of polyether sulfone; made of cellulose acetate and the like.
• a commercially available filter can be used as the filter. Examples of commercially available filters include GL chromatodisc non-aqueous systems manufactured by GL Sciences Co., Ltd. The pore size of the filter is about 0.1 to 1 ⁇ m.
• the temperature at which the non-aqueous electrolytic solution (B) is filtered is not particularly limited, but is preferably in the range of 0 to 70 ° C, more preferably 0 to 50 ° C, and even more preferably 20 to 50 ° C.
• one-stage filtration may be performed, or two-stage or more multi-stage filtration may be performed.
• cleaning may be performed if necessary after filtration.
• the non-aqueous electrolyte solution (C) can be obtained by filtering the obtained non-aqueous electrolyte solution (B) after adding a carbonate or the like to the non-aqueous electrolyte solution (A) containing an electrolyte salt.
• the interfacial resistance is reduced, side reactions during charging and discharging are suppressed, and the electrolyte salt is continuously decomposed and the gas is continuously decomposed in the battery. Since the generation is suppressed, the battery performance is further improved.
• the lithium ion secondary battery according to the present embodiment is housed in an outer case together with a separator provided between an electrode (positive electrode and negative electrode), a positive electrode and a negative electrode, and a state in which the separator is impregnated with the positive electrode and the negative electrode. It is provided with a non-aqueous electrolyte solution. In this lithium ion secondary battery, the non-aqueous electrolytic solution according to the present embodiment is used.
• the positive electrode includes a positive electrode current collector and a positive electrode mixture layer, and the positive electrode mixture layer is formed on the positive electrode current collector.
• Examples of the metal used for the positive electrode current collector include iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum and the like. Of these, aluminum is preferred.
• the shape and dimensions of the positive electrode current collector are not particularly limited.
• the positive electrode mixture layer is formed from the positive electrode composition.
• the positive electrode composition contains a positive electrode active material, a conductive auxiliary agent, a binder, a solvent for dispersing these components, and the like.
• the positive electrode active material may be any as long as it can occlude and release lithium ions, and a generally used positive electrode active material can be used.
• the positive electrode active material include metal oxides containing lithium.
• the lithium-containing metal oxide include lithium cobalt oxide, lithium iron phosphate, lithium manganese phosphate, lithium manganate, lithium nickel manganese cobalt oxide, and lithium nickel cobalt aluminum composite oxide.
• the positive electrode active material may be used alone or in combination of two or more.
• the content of the positive electrode active material in the non-volatile content of the positive electrode composition is preferably 70 to 98.8% by mass, more preferably 80 to 98.3, from the viewpoint of improving the output characteristics and electrical characteristics of the lithium ion secondary battery. It is mass%.
• Conductive aids are used to improve the output of lithium-ion secondary batteries.
• conductive carbon is mainly used.
• the conductive carbon include carbon black, fibrous carbon, graphite and the like.
• carbon black is preferable.
• carbon black include Ketjen black and acetylene black.
• the content of the conductive auxiliary agent in the non-volatile content of the positive electrode composition is preferably 1 to 20% by mass, more preferably 1.5 to 10% by mass from the viewpoint of improving the output characteristics and electrical characteristics of the lithium ion secondary battery. Is.
• fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene
• synthetic rubbers such as styrene-butadiene rubber and nitrile butadiene rubber
• polyamide resins such as polyamideimide
• polyolefin resins such as polyethylene and polypropylene.
• the binders may be used alone or in combination of two or more. Further, the binder may be in a state of being dissolved in a solvent at the time of use or in a state of being dispersed in a solvent.
• the solvent examples include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methylethylketone, tetrahydrofuran, acetonitrile, acetone, ethanol, ethyl acetate, water and the like.
• the solvent may be used alone or in combination of two or more.
• the amount of the solvent used is not particularly limited, and may be appropriately determined according to the production method and the material used.
• a non-fluoropolymer such as a (meth) acrylic polymer, a nitrile polymer, a diene polymer, a polymer such as a fluoropolymer such as polytetrafluoroethylene, and the like.
• Emulsifiers such as anionic emulsifiers, nonionic emulsifiers, and cationic emulsifiers; dispersants such as styrene-maleic acid copolymers and polymer dispersants such as polyvinylpyrrolidone, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyacrylic acid (salts).
• An alkali-soluble (meth) acrylic acid- (meth) acrylic acid ester copolymer and other thickeners, preservatives and the like may be contained.
• the content of other components in the non-volatile content of the positive electrode composition is preferably 0 to 15% by mass, more preferably 0 to 10% by mass.
• the positive electrode composition can be prepared, for example, by mixing a positive electrode active material, a conductive auxiliary agent, a binder, a solvent, and if necessary, other components, and dispersing them using a bead mill, a ball mill, a stirring type mixer, or the like. ..
• the negative electrode includes a negative electrode current collector and a negative electrode mixture layer, and the negative electrode mixture layer is formed on the negative electrode current collector.
• Examples of the metal used for the negative electrode current collector include iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum and the like. Of these, copper is preferred.
• the shape and dimensions of the negative electrode current collector are not particularly limited.
• the negative electrode mixture layer is formed from the negative electrode composition.
• the negative electrode composition contains a negative electrode active material, a conductive auxiliary agent, a binder, a solvent for dispersing these components, and the like.
• the negative electrode active material examples include carbon materials such as graphite, natural graphite, and artificial graphite, polyacene-based conductive polymers, composite metal oxides such as lithium titanate, lithium alloys, and silicon-based materials.
• the negative electrode active material may be used alone or in combination of two or more.
• the content of the negative electrode active material in the non-volatile content of the negative electrode composition is preferably 85 to 99.7% by mass, more preferably 90 to 99.5, from the viewpoint of improving the output characteristics and electrical characteristics of the lithium ion secondary battery. It is mass%.
• the same ones used for the positive electrode composition can be used.
• the content of the conductive auxiliary agent in the non-volatile content of the negative electrode composition is preferably 1 to 20% by mass, more preferably 1.5 to 10% by mass from the viewpoint of improving the output characteristics and electrical characteristics of the lithium ion secondary battery. Is.
• the negative electrode composition may contain other components such as a dispersant, a thickener, and a preservative as other components, if necessary.
• the content of other components in the non-volatile content of the negative electrode composition is preferably 0 to 15% by mass, more preferably 0 to 10% by mass, from the viewpoint of improving the output characteristics and electrical characteristics of the lithium ion secondary battery. ..
• the negative electrode composition can be prepared, for example, by mixing a negative electrode active material, a conductive auxiliary agent, a binder, a solvent, and if necessary, other components, and dispersing them using a bead mill, a ball mill, a stirring type mixer, or the like. ..
• the electrode can be manufactured, for example, by applying an electrode composition to a current collector and drying it to form an electrode mixture layer. If necessary, the electrodes may be pressurized by using, for example, a die press or a roll press.
• separator As the separator, polyolefin resins such as polyethylene, polypropylene and polymethylpentene, fluororesins, polyester resins such as polyethylene terephthalate (PET), polyamide resins such as nylon, cellulose resins (cellulose fibers) and polyparaphenylene.
• PET polyethylene terephthalate
• a film made of an aramid resin such as terephthalamide, an acrylic resin, a polyvinyl alcohol resin or the like can be used.
• the secondary battery according to the present embodiment is, for example, by superimposing a positive electrode and a negative electrode on each other via a separator, putting the obtained laminate in a battery container, injecting a non-aqueous electrolytic solution into the battery container, and sealing the battery. , Easy to manufacture.
• expanded metal, fuses, overcurrent prevention elements such as PTC elements, lead plates, etc. may be placed in the battery container to prevent pressure rise and overcharge / discharge inside the battery.
• Examples of the shape of the battery include a coin type, a button type, a sheet type, a cylindrical type, a square type, a flat type, and the like, but the present disclosure is not limited to such an example.
• Example 1 Preparation of non-aqueous electrolyte solution> (Example 1) to (Example 3)
• EC ethylene carbonate
• EMC ethylmethyl carbonate
• LiFSI Co., Ltd.
• LiPF 6 electrolyte salt
• potassium nitrosodisulfonate manufactured by Sigma Aldrich
• a non-aqueous electrolyte mass ratio nitrogen in 100% by mass of the non-aqueous electrolyte solution.
• a non-aqueous electrolyte solution was prepared by adding so that the amount of potassium was 0.5% by mass and stirring for 1 day.
• Table 1 shows the electrolyte salt composition of the obtained non-aqueous electrolyte solution, the types of nitroxy radical group-containing compounds, and the types of other additives (the same applies hereinafter).
• Example 4 To the non-aqueous electrolyte solution obtained in Example 3, LiH 2 NSO 3 and Li 2 CO 3 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added as other additives to each of the non-aqueous electrolyte solutions at a mass ratio of 0.5. It was added so as to be by mass, and the mixture was stirred for 1 day.
• a non-aqueous electrolyte solution was prepared by filtering the obtained non-aqueous electrolyte solution using a filter having a pore size of 0.45 ⁇ m (GL Chromatodisk non-aqueous system 13N manufactured by GL Sciences Co., Ltd.).
• LiH 2 NSO 3 was prepared as follows. H 3 NSO 3 was slurried with pure water. Lithium hydroxide monohydrate was added to the slurry while stirring the obtained slurry and monitoring the heat generation. Subsequently, the insoluble matter of the slurry was filtered. Finally, the filtrate was dried under reduced pressure at 80 ° C. When the obtained LiH 2 NSO 3 was analyzed by XRD (manufactured by Spectris Co., Ltd., product number: X PERT-MPD), no impurities could be confirmed.
• XRD manufactured by Spectris Co., Ltd., product number: X PERT-MPD
• Example 1 A non-aqueous electrolytic solution was prepared in the same manner as in Example 1 except that potassium nitrosodisulfonate was not added to the non-aqueous electrolytic solution.
• Example 2 A non-aqueous electrolytic solution was prepared in the same manner as in Example 2 except that potassium nitrosodisulfonate was not added to the non-aqueous electrolytic solution.
• Example 3 A non-aqueous electrolytic solution was prepared in the same manner as in Example 3 except that potassium nitrosodisulfonate was not added to the non-aqueous electrolytic solution.
• the obtained positive electrode mixture slurry was applied to an aluminum foil (positive electrode current collector, manufactured by Nippon Foil Co., Ltd., thickness 15 ⁇ m) so that the coating weight after drying was 19.4 mg / cm 2.
• an aluminum foil positive electrode current collector, manufactured by Nippon Foil Co., Ltd., thickness 15 ⁇ m
• the coating weight after drying was 19.4 mg / cm 2.
• a sheet-shaped (thickness 83 ⁇ m) positive electrode was obtained by pressure molding with a roll press machine until the density became 3.1 g / cm 3.
• the obtained negative electrode mixture slurry was applied to a copper foil (negative electrode current collector, manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., thickness 15 ⁇ m), and the coating weight after drying was 12.7 g / cm 2 . It was coated on one side with an applicator so as to be, and dried on a hot plate at 80 ° C. for 10 minutes. Further, it was dried in a vacuum drying oven at 100 ° C. for 12 hours. Then, a negative electrode in the form of a sheet (thickness 113 ⁇ m) was obtained by pressure molding with a roll press machine until the density became 1.3 g / cm 3.
• the obtained laminated battery was used with a charge / discharge test device (manufactured by Asuka Electronics Co., Ltd., product number: ACD-01, the same applies hereinafter) and has a current value of 0.1 C (3 mA) at room temperature (25 ° C., the same applies hereinafter). Charged for 90 minutes. After charging, one side of the sealing portion was cleaved to degas, and then the one side was resealed in vacuum. Then, it was left at room temperature for 3 days. After being left to stand, it was charged with a constant current and constant voltage (CCCV) at 0.5 C (15 mA) and 4.2 V for 5 hours at room temperature.
• CCCV constant current and constant voltage
• the frequency at which the arc diverges is the frequency at which the imaginary axis value reaches the minimum between 100 Hz and 0.01 Hz in the case of measurement at 25 ° C., and the frequency is 10 Hz to 0. This is the frequency at which the imaginary axis value reaches the minimum between 001 Hz.
• the reduction rate of the actual shaft resistance is the actual shaft resistance (ratio) of the example having the same salt composition as that of the comparative example, based on the actual shaft resistance of the comparative example (that is, “1”).
• the reduction rate of the actual shaft resistance of Example 1 is a ratio based on the actual shaft resistance of Comparative Example 1.
• the reduction rate of the actual shaft resistance of Example 2 is a ratio based on the actual shaft resistance of Comparative Example 2.
• the reduction rate of the actual shaft resistance of Examples 3 and 4 is a ratio based on the actual shaft resistance of Comparative Example 3.
• the standard comparison example for each example is the same.
• the cell after being stored at 60 ° C. for 14 days was charged at 2.4 V at 25 ° C. for 3 hours at 1 C (30 mA) and left at 85 ° C. for 3 days.
• the cell after being left to stand was cooled at 25 ° C., it was discharged at 25 ° C. at 1 C (30 mA) until the end of 2.75 V.
• a constant current constant voltage charge was performed at 25 ° C. at 4.2 V and 1 C (30 mA) at 0.6 mA termination, and the discharge capacity was confirmed by the discharge at 1 C (30 mA) and 2.75 termination.
• the measurement results are shown in the column of "Discharge capacity" in "Leave at 85 ° C. for 3 days" in Table 1.
• discharge capacity after high temperature storage the improvement rate of the discharge capacity after storage at 60 ° C. for 14 days or after leaving at 85 ° C. for 3 days. It refers to the discharge capacity (ratio) after high-temperature storage of an example having the same salt composition as that of the comparative example, based on the discharge capacity (that is, “1”).
• the improvement rate of the discharge capacity after high-temperature storage in Example 1 is based on the following (Equation 2): based on the discharge capacity after high-temperature storage in Comparative Example 1.
• Capacity maintenance rate (%) (1C capacity in the 300th cycle / 1C capacity in the 1st cycle) x 100 (Equation 3)
• the improvement rate of the volume retention rate after the 300-cycle test is the volume of the example having the same salt composition as that of the comparative example, based on the volume retention rate of the comparative example (that is, “1”).
• the maintenance rate (ratio) is the volume of the example having the same salt composition as that of the comparative example, based on the volume retention rate of the comparative example (that is, “1”).
• Example 1 is compared with Comparative Example 1 having the same salt composition
• Example 2 is compared with Comparative Example 2 having the same salt composition
• Examples 3 to 4 have the same salt composition. It can be seen that the actual shaft resistance and DCR are reduced and the discharge capacity and cycle characteristics after high temperature storage are improved as compared with Comparative Example 3.
• Examples 2 and 3 of the mixed salt composition of LiFSI and LiPF 6 have a smaller actual shaft resistance than Example 1 of the LiPF 6 single salt composition, and have a discharge capacity after high temperature storage and after a 300 cycle test. Not only the capacity retention rate is large, but also the reduction rate of actual shaft resistance and DCR, and the improvement rate of the discharge capacity after high temperature storage and the capacity retention rate after 300 cycle test are compared with the standard comparative example of the same salt composition. large. Therefore, it can be seen that the non-aqueous electrolytic solution having a mixed salt composition of LiFSI and LiPF 6 has a greater effect of improving the battery performance by adding a compound having a nitroxy radical group than the non-aqueous electrolytic solution having a LiPF 6 elemental salt composition.
• a non-aqueous electrolyte containing LiFSI it is excellent in ionic conductivity than the non-aqueous electrolyte LiPF 6 alone salt composition, LiFSI suppresses the decomposition of LiPF 6, LiPF 6 decomposition from It is considered that side reactions are suppressed, LiFSI promotes ion adsorption / desorption of compounds having a nitroxy radical group, and the like.
• the non-aqueous electrolytic solution according to the present embodiment contains a compound having a nitroxy radical group together with a lithium salt and an electrolytic solution solvent, the lithium ion secondary battery in which the non-aqueous electrolytic solution is used is a battery. As a result, the inconvenience of lowering the energy density per volume does not occur.
• the non-aqueous electrolytic solution is obtained by dissolving a compound having a nitroxy radical group in a non-aqueous electrolytic solution containing a lithium salt and an electrolytic solution solvent, and a compound having a nitroxy radical group and a conductive material are mixed. Since it is not necessary to combine them, the manufacturing process of the lithium ion secondary battery using the non-aqueous electrolytic solution is easy.
• the interfacial resistance is reduced, and the DC resistance is reduced accordingly, and the high temperature durability performance and the cycle characteristics are improved (in other words, the interfacial resistance and the interfacial resistance and the cycle characteristics are improved. It is possible to suppress an increase in DC resistance and a decrease in high temperature durability performance and cycle characteristics).
• the present disclosure is suitable for a non-aqueous electrolytic solution used in a lithium ion secondary battery.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Inorganic Chemistry (AREA)
• Secondary Cells (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=75848377

Family Applications (1)

Country Status (2)

Cited By (2)

Citations (3)

Family Cites Families (1)

• 2020
  • 2020-10-23 WO PCT/JP2020/039886 patent/WO2021090709A1/ja not_active Ceased
  • 2020-10-23 JP JP2021554889A patent/JP7245355B2/ja active Active

Patent Citations (3)

Also Published As

Similar Documents

Legal Events