WO2018179990A1 - 半固体電解液、半固体電解質、半固体電解質層、電極、二次電池 - Google Patents
半固体電解液、半固体電解質、半固体電解質層、電極、二次電池 Download PDFInfo
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- WO2018179990A1 WO2018179990A1 PCT/JP2018/005661 JP2018005661W WO2018179990A1 WO 2018179990 A1 WO2018179990 A1 WO 2018179990A1 JP 2018005661 W JP2018005661 W JP 2018005661W WO 2018179990 A1 WO2018179990 A1 WO 2018179990A1
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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
- H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
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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
- H01M10/0569—Liquid materials characterised by the solvents
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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
- H01M10/052—Li-accumulators
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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
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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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
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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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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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
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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
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
- H01M2300/0028—Organic electrolyte characterised by the solvent
- H01M2300/0037—Mixture of solvents
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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
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
- H01M2300/0045—Room temperature molten salts comprising at least one organic ion
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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
- H01M2300/00—Electrolytes
- H01M2300/0085—Immobilising or gelification of electrolyte
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- 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 invention relates to a semi-solid electrolyte, a semi-solid electrolyte, a semi-solid electrolyte layer, an electrode, and a secondary battery.
- Patent Document 1 discloses an electrolyte solution in which glymes having a high boiling point and a high flash point are mixed with a lithium salt. There is disclosed a method characterized in that battery life can be improved by using glymes excluding glyme.
- the mixed solution of triglyme and lithium bis (fluorosulfonyl) imide in Patent Document 1 has a high viscosity, so that the ion conductivity of lithium ions is low and the rate characteristics may be low.
- a low viscosity organic solvent such as a carbonate-based solvent
- the life of the secondary battery may be reduced depending on the mixing ratio of the mixed solution and the low viscosity organic solvent. is there.
- the present invention aims to improve the life and rate characteristics of a secondary battery.
- the life and rate characteristics of the secondary battery can be improved. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.
- Sectional drawing of the all-solid-state battery which concerns on one Embodiment of this invention The charging / discharging curve at the time of the first charging / discharging of an Example and a comparative example.
- a lithium ion secondary battery is an electrochemical device that can store or use electrical energy by occlusion / release of lithium ions to and from an electrode in a nonaqueous electrolyte. This is called by another name of a lithium ion battery, a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery, and any battery is a subject of the present invention.
- the technical idea of the present invention can be applied to sodium ion secondary batteries, magnesium ion secondary batteries, aluminum ion secondary batteries and the like in addition to lithium ion secondary batteries.
- FIG. 1 is a cross-sectional view of a secondary battery according to an embodiment of the present invention.
- the secondary battery 100 includes a positive electrode 70, a negative electrode 80, a battery case 30, and a semi-solid electrolyte layer 50.
- the battery case 30 houses the semi-solid electrolyte layer 50, the positive electrode 70, and the negative electrode 80.
- the material of the battery case 30 can be selected from materials that are corrosion resistant to non-aqueous electrolytes, such as aluminum, stainless steel, and nickel-plated steel.
- FIG. 1 shows a stacked secondary battery, the technical idea of the present invention can be applied to a wound secondary battery.
- an electrode body composed of the positive electrode 70, the semi-solid electrolyte layer 50, and the negative electrode 80 is laminated.
- the positive electrode 70 includes the positive electrode current collector 10 and the positive electrode mixture layer 40.
- a positive electrode mixture layer 40 is formed on both surfaces of the positive electrode current collector 10.
- the negative electrode 80 includes a negative electrode current collector 20 and a negative electrode mixture layer 60. Negative electrode mixture layers 60 are formed on both surfaces of the negative electrode current collector 20.
- the positive electrode current collector 10 and the negative electrode current collector 20 protrude outside the battery case 30, and the plurality of protruding positive electrode current collectors 10 and the plurality of negative electrode current collectors 20 are bonded together by, for example, ultrasonic bonding. As a result, a parallel connection is formed in the secondary battery 100.
- a bipolar secondary battery in which an electrical series connection is configured in the secondary battery 100 may be used.
- the positive electrode 70 or the negative electrode 80 may be referred to as an electrode
- the positive electrode mixture layer 40 or the negative electrode mixture layer 60 may be referred to as an electrode mixture layer
- the positive electrode current collector 10 or the negative electrode current collector 20 may be referred to as an electrode current collector.
- the positive electrode mixture layer 40 includes a positive electrode active material, a positive electrode conductive agent intended to improve the conductivity of the positive electrode mixture layer 40, and a positive electrode binder for binding them.
- the negative electrode mixture layer 60 includes a negative electrode active material, a negative electrode conductive agent intended to improve the conductivity of the negative electrode mixture layer 60, and a negative electrode binder for binding them.
- the semi-solid electrolyte layer 50 has a semi-solid electrolyte binder and a semi-solid electrolyte.
- the semi-solid electrolyte has inorganic particles and a semi-solid electrolyte.
- the positive electrode active material or the negative electrode active material may be referred to as an electrode active material
- the positive electrode conductive agent or the negative electrode conductive agent may be referred to as an electrode conductive agent
- the positive electrode binder or the negative electrode binder may be referred to as an electrode binder.
- the semi-solid electrolyte layer 50 is a material in which a lithium salt is dissolved in a semi-solid electrolyte solvent and mixed with oxide particles such as SiO 2 .
- the feature of the semi-solid electrolyte layer 50 is that there is no fluid electrolyte and the electrolyte is difficult to leak out.
- the semi-solid electrolyte layer 50 serves as a medium for transmitting lithium ions between the positive electrode 70 and the negative electrode 80 and also serves as an electronic insulator, thereby preventing a short circuit between the positive electrode 70 and the negative electrode 80.
- the semi-solid electrolyte When a semi-solid electrolyte is filled in the pores of the electrode mixture layer, the semi-solid electrolyte may be retained by adding the semi-solid electrolyte to the electrode mixture layer and absorbing it into the pores of the electrode mixture layer. . At this time, inorganic particles contained in the semi-solid electrolyte layer are not required, and the semi-solid electrolyte can be held by particles such as an electrode active material and an electrode conductive agent in the electrode mixture layer.
- a slurry in which a semisolid electrolyte, an electrode active material, and an electrode binder are mixed is prepared, and the electrode mixture layer is put together on the electrode current collector. There is a method of applying to.
- Electrode conductive agent As the electrode conductive agent, ketjen black, acetylene black or the like is preferably used, but is not limited thereto.
- Electrode binder examples include, but are not limited to, styrene-butadiene rubber, carboxymethyl cellulose, polyvinylidene fluoride (PVDF), and a mixture thereof.
- ⁇ Positive electrode active material> lithium ions are desorbed in the charging process, and lithium ions desorbed from the negative electrode active material in the negative electrode mixture layer are inserted in the discharging process.
- a lithium composite oxide containing a transition metal is preferable, and specific examples include LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiMnO 3 , LiMn 2 O 3 , LiMnO 2 , Li 4 Mn 5 O.
- ⁇ Positive electrode current collector 10 As the positive electrode current collector 10, an aluminum foil having a thickness of 10 to 100 ⁇ m or an aluminum perforated foil having a thickness of 10 to 100 ⁇ m and a hole diameter of 0.1 to 10 mm, an expanded metal, a foam metal plate, or the like is used. In addition to aluminum, stainless steel, titanium, etc. are also applicable. Any material can be used for the positive electrode current collector 10 without being limited by the material, shape, manufacturing method, or the like as long as it does not change during the use of the secondary battery, such as dissolution and oxidation.
- ⁇ Positive electrode 70> A positive electrode slurry obtained by mixing a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and an organic solvent is attached to the positive electrode current collector 10 by a doctor blade method, a dipping method, or a spray method, and then the organic solvent is dried.
- the positive electrode 70 can be produced by pressure forming with a roll press.
- a plurality of positive electrode mixture layers 40 can be laminated on the positive electrode current collector 10 by performing a plurality of times from application to drying.
- the thickness of the positive electrode mixture layer 40 is desirably equal to or greater than the average particle diameter of the positive electrode active material. This is because if the thickness of the positive electrode mixture layer 40 is made smaller than the average particle diameter of the positive electrode active material, the electron conductivity between the adjacent positive electrode active materials deteriorates.
- ⁇ Negative electrode active material> lithium ions are desorbed in the discharging process, and lithium ions desorbed from the positive electrode active material in the positive electrode mixture layer 40 are inserted in the charging process.
- the negative electrode active material include carbon materials (eg, graphite, graphitizable carbon materials, amorphous carbon materials), conductive polymer materials (eg, polyacene, polyparaphenylene, polyaniline, polyacetylene), lithium A composite oxide (for example, lithium titanate: Li 4 Ti 5 O 12 ), metal lithium, or a metal alloyed with lithium (for example, aluminum, silicon, tin) can be used, but is not limited thereto.
- the negative electrode current collector 20 is also made of a copper foil having a thickness of 10 to 100 ⁇ m, a copper perforated foil having a thickness of 10 to 100 ⁇ m and a pore diameter of 0.1 to 10 mm, an expanded metal, a foam metal plate, or the like. In addition to copper, stainless steel, titanium, nickel, etc. can also be applied. Any negative electrode current collector 20 can be used without being limited by the material, shape, manufacturing method and the like.
- ⁇ Negative electrode 80> A negative electrode slurry in which a negative electrode active material, a negative electrode conductive agent, and an organic solvent containing a trace amount of water are mixed is attached to the negative electrode current collector 20 by a doctor blade method, a dipping method, a spray method, or the like, and then the organic solvent is dried.
- the negative electrode 80 can be produced by pressure molding with a roll press.
- a plurality of negative electrode mixture layers 60 can be laminated on the negative electrode current collector 20 by performing a plurality of times from application to drying.
- the thickness of the negative electrode mixture layer 60 is desirably equal to or greater than the average particle diameter of the negative electrode active material. This is because if the thickness of the negative electrode mixture layer 60 is made smaller than the average particle diameter of the negative electrode active material, the electron conductivity between the adjacent negative electrode active materials deteriorates.
- the inorganic particles are preferably insulative particles and insoluble in a semi-solid electrolytic solution containing an organic solvent or ionic liquid from the viewpoint of electrochemical stability.
- silica (SiO 2 ) particles, ⁇ -alumina (Al 2 O 3 ) particles, ceria (CeO 2 ) particles, and zirconia (ZrO 2 ) particles can be preferably used.
- other known metal oxide particles may be used.
- the average particle size of the primary particles of the inorganic particles is preferably 1 nm or more and 10 ⁇ m or less.
- the average particle diameter is larger than 10 ⁇ m, the inorganic particles cannot appropriately hold a sufficient amount of the semisolid electrolyte, and it may be difficult to form the semisolid electrolyte.
- the average particle diameter is smaller than 1 nm, the inter-surface force between the inorganic particles becomes large and the particles are likely to aggregate, which may make it difficult to form a semi-solid electrolyte.
- the average particle size of the primary particles of the inorganic particles is more preferably 1 nm to 50 nm, and still more preferably 1 nm to 10 nm.
- the average particle diameter can be measured using a transmission electron microscope (TEM).
- the semi-solid electrolyte has a semi-solid electrolyte solvent, a low viscosity solvent, optional additives, and optional electrolyte salts.
- the semi-solid electrolyte solvent has a mixture (complex) of an ether-based solvent and a solvated electrolyte salt exhibiting properties similar to those of an ionic liquid.
- An ionic liquid is a compound that dissociates into a cation and an anion at room temperature, and maintains a liquid state.
- the ionic liquid may be referred to as an ionic liquid, a low melting point molten salt or a room temperature molten salt.
- the semi-solid electrolyte solvent is desirably a low volatility, specifically, a vapor pressure at room temperature of 150 Pa or less from the viewpoint of stability in the air and heat resistance in the secondary battery.
- the content of the semi-solid electrolyte in the electrode is preferably 20% by volume to 40% by volume.
- the content of the semi-solid electrolytic solution is less than 20%, the ion conduction path inside the electrode is not sufficiently formed, and the rate characteristic may be deteriorated.
- content of a semi-solid electrolyte solution is larger than 40% or more, a semi-solid electrolyte solution may leak from an electrode.
- the ether solvent constitutes a solvated electrolyte salt and a solvated ionic liquid.
- a symmetrical glyme RO (CH 2 CH 2 O) n—R ′ (R and R ′ are saturated hydrocarbons, and n is an integer)
- ionic liquids Generic name for glycol diether.
- tetraglyme tetraethylene dimethyl glycol, G4
- triglyme triethylene glycol dimethyl ether, G3
- pentaglime pentaglime
- pentaglime pentaglime
- crown ether (a general term for macrocyclic ethers represented by (—CH 2 —CH 2 —O) n (n is an integer)) can be used as an ether solvent. Specifically, 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6 and the like can be preferably used, but are not limited thereto. These crown ethers may be used alone or in combination. Among these, it is preferable to use tetraglyme or triglyme in that a complex structure can be formed with a solvated electrolyte salt that is a lithium salt.
- solvated electrolyte salt imide salts such as LiFSI, LiTFSI, and LiBETI can be used, but are not limited thereto.
- semi-solid electrolyte solvent a mixture of an ether solvent and a solvated electrolyte salt may be used alone or in combination.
- electrolyte salt e.g., LiPF 6, LiBF 4, LiClO 4, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, lithium bis oxalate borate (LiBOB), LiFSI, LiTFSI, the LiBTFI like preferably Can be used.
- electrolyte salts may be used alone or in combination.
- ⁇ Low viscosity solvent> By including a low-viscosity solvent in the semi-solid electrolyte, the viscosity of the semi-solid electrolyte can be lowered.
- organic solvents such as propylene carbonate, ethylene carbonate, dimethyl carbonate, ionic liquids such as N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, Hydrofluoroethers (for example, 1,1,2,2-tetrafluoroethyl-12,2,3,3-tetrafluoropropyl ether) and the like can be used.
- the low viscosity solvent preferably has a lower viscosity than a mixed solution of an ether solvent and a solvated electrolyte salt. It is desirable that the solvation structure of the ether solvent and the solvated electrolyte salt is not greatly disturbed. Specifically, those having the same number of donors as those of ether solvents such as glyme or crown ether, or those having a small number of donors, such as propylene carbonate, ethylene carbonate, acetonitrile, dichloroethane, dimethyl carbonate, 1,1, 2,2-tetrafluoroethyl-12,2,3,3-tetrafluoropropyl ether and the like can be preferably used.
- low viscosity solvents may be used alone or in combination.
- ethylene carbonate is preferable, and propylene cardnate is particularly preferable. Since ethylene carbonate and propylene cardnate have a high boiling point, they are less likely to volatilize when a low-viscosity solvent is contained in the electrode, and are less susceptible to changes in the composition of the semi-solid electrolyte due to volatilization.
- the mixing ratio of the ether solvent to the solvated electrolyte salt is preferably 0.5 or more and 1.5 or less, particularly preferably 0.5 or more and 1.2 or less, and more preferably 0.5 or more and 0.8 or less in terms of mole. By setting it as said range, all the ether solvents introduced into the semi-solid electrolyte form a solvated electrolyte salt and a solvated structure, and the redox decomposition of the ether solvent on the electrode can be suppressed.
- the mixing ratio of the low-viscosity solvent to the electrolyte salt is preferably 4 or more and 16 or less, particularly preferably 4 or more and 12 or less, and more preferably 4 or more and 6 or less in terms of mole. By setting it as said range, the viscosity of a semi-solid electrolyte can be fully reduced and a rate characteristic can be improved.
- additives Even if it is a low-viscosity solvent which does not satisfy
- the addition amount of the additive is preferably 30% by mass or less, particularly preferably 10% by mass or less, based on the weight of the semisolid electrolytic solution. If it is 30 mass percent, even if an additive is introduced, the solvation structure of the glyme or crown ether solvent and the solvated electrolyte salt is not greatly disturbed.
- vinylene carbonate, fluoroethylene carbonate and the like can be preferably used. These additives may be used alone or in combination.
- ⁇ Semi-solid electrolyte binder As the semi-solid electrolyte binder, a fluorine-based resin is preferably used. As the fluororesin, polytetrafluoroethylene (PTFE) is preferably used. By using PTFE, the adhesion between the semi-solid electrolyte layer 50 and the electrode current collector is improved, so that the battery performance is improved.
- PTFE polytetrafluoroethylene
- a semi-solid electrolyte is constituted by carrying (holding) the semi-solid electrolyte on inorganic particles.
- a semi-solid electrolyte and inorganic particles are mixed at a specific volume ratio, an organic solvent such as methanol is added and mixed, and a slurry of the semi-solid electrolyte is prepared. It is spread on a petri dish and the organic solvent is distilled off to obtain a semi-solid electrolyte powder.
- ⁇ Semi-solid electrolyte layer 50> As a method for producing the semi-solid electrolyte layer 50, a semi-solid electrolyte powder is compression-molded into a pellet using a molding die or the like, or a semi-solid electrolyte binder is added to and mixed with the semi-solid electrolyte powder to form a sheet. There are methods.
- a highly flexible semi-solid electrolyte layer 50 (electrolyte sheet) can be produced by adding and mixing an electrolyte binder powder to the semi-solid electrolyte.
- the semi-solid electrolyte layer 50 can be produced by adding and mixing a solution of a binder in which a semi-solid electrolyte binder is dissolved in a dispersion solvent to the semi-solid electrolyte and distilling off the dispersion solvent. Moreover, you may produce the semi-solid electrolyte layer 50 by apply
- the content of the semi-solid electrolytic solution in the semi-solid electrolyte layer 50 is desirably 70% by volume or more and 90% by volume or less. When the content of the semisolid electrolyte is larger than 70% by volume, the interface resistance between the electrode and the semisolid electrolyte layer 50 may be significantly increased. Further, when the content of the semi-solid electrolyte is larger than 90%, the semi-solid electrolyte may leak from the semi-solid electrolyte layer 50.
- a microporous membrane may be added to the semisolid electrolyte layer 50.
- the microporous film polyolefin such as polyethylene or polypropylene, glass fiber, or the like can be used.
- the semi-solid electrolyte layer 50 that insulates the positive electrode 70 and the negative electrode 80 a microporous film not containing a semi-solid electrolyte may be used.
- the secondary battery 100 particularly the microporous membrane, is filled with the semi-solid electrolyte.
- coated the slurry which made the oxide inorganic particle contain the binder on the electrode or the microporous film.
- the oxide inorganic particles include silica particles, ⁇ -alumina particles, ceria particles, zirconia particles, and the like. These materials may be used alone or in combination.
- the above-mentioned semi-solid electrolyte binder can be used as the binder.
- ⁇ Negative electrode 80> Graphite (amorphous coating, average particle size 10 ⁇ m), polyvinylidene fluoride (PVDF), and conductive additive (acetylene black) are mixed at a weight ratio of 88: 10: 2, and N-methyl-2-pyrrolidone is mixed.
- a slurry-like solution was prepared by further mixing. The prepared slurry was applied to a current collector made of SUS foil having a thickness of 10 ⁇ m using a doctor blade and dried at 80 ° C. for 2 hours or more. At this time, the coating amount of the slurry was adjusted so that the weight of the negative electrode mixture layer 60 per 1 cm 2 after drying was 8 mg / cm 2 . The dried electrode was pressurized to a density of 1.5 g / cm 3 and punched out at ⁇ 13 mm to obtain a negative electrode 80.
- ⁇ Secondary battery> The produced negative electrode 80 was dried at 100 ° C. for 2 hours or more and then transferred into a glove box filled with argon. Next, an appropriate amount of the semi-solid electrolytic solution was added to the negative electrode 80 or a separator made of polypropylene and having a thickness of 30 ⁇ m, and the electrolytic solution was permeated into the negative electrode 80 or the separator. Then, the secondary battery 100 of Example 1 was obtained by putting in the 2032 size coin-type battery cell holder in the state which arrange
- a secondary battery 100 was produced in the same manner as in Example 1 except that the mixing molar ratio of LiTFSI, G4, and PC was set to 1: 0.8: 5 in the semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 1 except that the mixed molar ratio of LiTFSI, G4, and PC was 1: 0.6: 5 in the semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 1 except that the mixing molar ratio of LiTFSI, G4, and PC was 1: 1.2: 5 in the semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 1 except that the mixing molar ratio of LiTFSI, G4, and PC was 1: 1: 8 in the semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 1 except that the mixing molar ratio of LiTFSI, G4, and PC was set to 1: 0.8: 8 in the semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 1 except that the mixing molar ratio of LiTFSI, G4, and PC was 1: 0.6: 8 in the semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 1 except that the mixing molar ratio of LiTFSI, G4, and PC was 1: 1.2: 8 in the semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 1 except that the electrolyte salt used in the semisolid electrolyte was changed from LiTFSI to LiFSI.
- a secondary battery 100 was produced in the same manner as in Example 1 except that 10% by mass of vinylene carbonate was added to the semisolid electrolyte.
- Secondary battery 100 was fabricated in the same manner as in Example 1 except that tetraglyme (G4) was changed to triglyme (G3) in the semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 11 except that in the semi-solid electrolyte, the mixing molar ratio of LiTFSI, G3, and PC was 1: 0.75: 5.
- a secondary battery 100 was produced in the same manner as in Example 11 except that in the semi-solid electrolyte, the mixing molar ratio of LiTFSI, G3, and PC was 1: 0.5: 5.
- Secondary battery 100 was fabricated in the same manner as in Example 11 except that in the semi-solid electrolyte, the mixing molar ratio of LiTFSI, G3, and PC was 1: 1.25: 5.
- a secondary battery 100 was produced in the same manner as in Example 11 except that in the semi-solid electrolyte, the mixing molar ratio of LiTFSI, G3, and PC was set to 1: 1.5: 5.
- Secondary battery 100 was fabricated in the same manner as in Example 11 except that in the semi-solid electrolyte, the mixing molar ratio of LiTFSI, G4, and PC was 1: 1: 1.
- Secondary battery 100 was fabricated in the same manner as in Example 11 except that in the semi-solid electrolyte, the mixing molar ratio of LiTFSI, G4, and PC was 1: 1: 16.
- a secondary battery 100 was produced in the same manner as in Example 1 except that G4 was replaced with 12-crown-4-ether in a semisolid electrolyte.
- a secondary battery 100 was produced in the same manner as in Example 1 except that PC was changed to ethylene carbonate in the semi-solid electrolyte.
- ⁇ Semi-solid electrolyte layer 50> LiTFSI, G4, and PC were mixed to prepare a semi-solid electrolyte.
- a semi-solid electrolyte and SiO 2 nanoparticles (particle size: 7 nm) were mixed at a volume fraction of 80:20, methanol was added thereto, and the mixture was stirred for 30 minutes using a magnetic stirrer. . Thereafter, the obtained mixed solution was spread on a petri dish, and methanol was distilled off to obtain a powdery semi-solid electrolyte.
- ⁇ Secondary battery 100> The obtained semi-solid electrolyte layer 50 was punched out with a size of ⁇ 15 mm. After that, the negative electrode 80 produced by the same procedure as in Example 1 on one side of the semi-solid electrolyte layer 50 and the lithium metal on the other side are placed in a 2032 size coin-type battery cell holder and sealed by a caulking machine. A secondary battery 100 was obtained.
- Secondary battery 100 was fabricated in the same manner as in Example 20 except that in the semi-solid electrolyte layer 50, the mixing molar ratio of LiTFSI, G4, and PC was 1: 0.8: 5.
- a secondary battery 100 was produced in the same manner as in Example 21 except that 10 mass percent of vinylene carbonate was added to the semi-solid electrolyte layer 50.
- a secondary battery 100 was produced in the same manner as in Example 21 except that the lithium salt used for the semisolid electrolyte layer 50 was changed from LiTFSI to LiFSI.
- ⁇ Positive electrode 70> By mixing the positive electrode active material LiNiMnCoO 2 with polyvinylidene fluoride (PVDF) and a conductive additive (acetylene black) in a weight ratio of 84: 9: 7, adding N-methyl-2-pyrrolidone and further mixing. A slurry solution was prepared. The prepared slurry was applied to a current collector made of SUS foil having a thickness of 10 ⁇ m using a doctor blade and dried at 80 ° C. for 2 hours or more. At this time, the application amount of the slurry was adjusted so that the weight of the positive electrode mixture layer 40 per 1 cm 2 after drying was 18 mg / cm 2 . Pressurization was performed so that the density after drying was 2.5 g / cm 3, and punched out with a diameter of 13 mm to obtain a positive electrode 70.
- PVDF polyvinylidene fluoride
- acetylene black acetylene black
- a secondary battery 100 was produced in the same manner as in Example 1 except that the positive electrode 70 of this example was used instead of the lithium metal of Example 1.
- a secondary battery 100 was produced in the same manner as in Example 24 except that in the semi-solid electrolyte layer 50, the mixing molar ratio of LiTFSI, G4, and PC was 1: 0.8: 5.
- a secondary battery 100 was produced in the same manner as in Example 24 except that 10% by mass of vinylene carbonate was added to the semi-solid electrolyte layer 50.
- a secondary battery 100 was produced in the same manner as in Example 24 except that the lithium salt used in the semisolid electrolyte layer 50 was changed from LiTFSI to LiFSI.
- a laminate of the positive electrode 70 / semi-solid electrolyte layer 50 / bipolar electrode / semi-solid electrolyte layer 50 / negative electrode 80 in this order was placed in a coin battery cell container and sealed with a caulking machine to obtain a bipolar secondary battery 100.
- the negative electrode 80 and the positive electrode 70 of the bipolar electrode were opposed to the negative electrode 80 and the positive electrode 70 through the joined semi-solid electrolyte layer 50, respectively.
- a secondary battery 100 was produced in the same manner as in Example 28 except that in the semi-solid electrolyte layer 50, G4 was changed to G3.
- a secondary battery 100 was fabricated in the same manner as in Example 28 except that in the semi-solid electrolyte layer 50, the mixing molar ratio of LiTFSI, G3, and PC was 1: 0.75: 5. [Comparative Example 1]
- a secondary battery 100 was produced in the same manner as in Example 1 except that in the semi-solid electrolyte layer 50, the mixing molar ratio of LiTFSI, G4, and PC was 1: 1: 0. [Comparative Example 2]
- a secondary battery 100 was produced in the same manner as in Example 1 except that in the semi-solid electrolyte layer 50, the mixing molar ratio of LiTFSI, G4, and PC was 1: 0: 3. [Comparative Example 3]
- a secondary battery 100 was fabricated in the same manner as in Example 1 except that the semi-solid electrolyte layer 50 was mixed at a molar ratio of LiTFSI, G4, and PC of 1: 0: 4. [Comparative Example 4]
- a secondary battery 100 was produced in the same manner as in Example 1 except that in the semi-solid electrolyte layer 50, the mixing molar ratio of LiTFSI, G4, and PC was 1: 0: 8. [Comparative Example 5]
- a secondary battery 100 was produced in the same manner as in Example 1 except that the semi-solid electrolyte layer 50 was mixed at a 1: 1 molar ratio of LiTFSI, G4, and PC. [Comparative Example 6]
- a secondary battery 100 was produced in the same manner as in Example 1 except that in the semi-solid electrolyte layer 50, the mixing molar ratio of LiTFSI, G4, and PC was 1: 1: 2.
- a secondary battery 100 was produced in the same manner as in Example 20 except that the semi-solid electrolyte layer 50 was mixed with LiTFSI, G4, and PC at a molar ratio of 1: 1: 0. [Comparative Example 8]
- a secondary battery 100 was produced in the same manner as in Comparative Example 7, except that the lithium salt used for the semi-solid electrolyte layer 50 was changed from LiTFSI to LiFSI. [Comparative Example 9]
- a secondary battery 100 was produced in the same manner as in Example 1 except that ⁇ -butyllactone (GBL) was used instead of PC in the semi-solid electrolyte layer 50.
- GBL ⁇ -butyllactone
- a secondary battery 100 was produced in the same manner as in Example 1 except that trimethyl phosphate (TMP) was used instead of PC in the semi-solid electrolyte layer 50.
- TMP trimethyl phosphate
- a secondary battery 100 was produced in the same manner as in Example 1 except that triethyl phosphate (TEP) was used instead of PC in the semi-solid electrolyte layer 50.
- TEP triethyl phosphate
- a secondary battery 100 was fabricated in the same manner as in Example 1 except that in the semi-solid electrolyte layer 50, the mixing molar ratio of LiTFSI, G4, and PC was 1: 2: 5.
- the secondary battery 100 is required to have high life and high rate characteristics.
- the evaluation criteria for the lifetime was that the Coulomb efficiency (the ratio between the discharge capacity and the charge capacity) at the first charge / discharge was 70% or more.
- the capacity maintenance ratio (discharge capacity / discharge capacity at 0.05 C rate ⁇ 100) is 90% at a 0.5 C rate (current value at which the design capacity of the battery is fully charged in 2 hours). It was a condition that it was above.
- the amount of liquid in the electrode (% by volume) was calculated based on the porosity of the negative electrode 80.
- FIG. 4 summarizes the results of the examples and comparative examples in numerical form. Regarding the rate characteristics, only the value of the capacity maintenance rate at the 0.5 C rate is shown. Referring to FIG. 4, it is apparent that Examples 1 to 30 are superior in terms of life and rate characteristics as compared with Comparative Examples 1 to 12. Details are described below.
- FIG. 2 shows a charge / discharge curve at the first charge / discharge.
- the discharge capacity exceeded 90% of the designed capacity, and the coulomb efficiency exceeded 70%.
- the discharge capacity was only about 40% of the designed capacity, and the coulomb efficiency was only about 50%.
- the secondary battery could not be charged due to the side reaction of PC, and a desired discharge capacity could not be obtained. From the above results, it can be seen that the discharge capacity and coulomb efficiency of the secondary battery were improved by this example. This means that the present invention is effective in improving the battery life.
- Fig. 3 shows the rate characteristics of the battery.
- the capacity retention rate at the 1C rate achieved 90% or more, and an improvement in ionic conductivity could be confirmed.
- the capacity retention rate at the 1C rate was 20% or less.
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Abstract
Description
電極導電剤としては、ケッチェンブラック、アセチレンブラック等が好適に用いられるが、これに限られない。
電極バインダとしては、スチレン-ブタジエンゴム、カルボキシメチルセルロ-ス、ポリフッ化ビニリデン(PVDF)及びこれらの混合物等が挙げられるが、これに限られない。
正極活物質は、充電過程においてリチウムイオンが脱離し、放電過程において負極合剤層中の負極活物質から脱離したリチウムイオンが挿入される。正極活物質の材料として、遷移金属を含むリチウム複合酸化物が好ましく、具体例としては、LiCoO2、LiNiO2、LiMn2O4、LiMnO3、LiMn2O3、LiMnO2、Li4Mn5O12、LiMn2-xMxO2(ただし、M=Co、Ni、Fe、Cr、Zn、Ta、x=0.01~0.2)、Li2Mn3MO8(ただし、M=Fe、Co、Ni、Cu、Zn)、Li1-xAxMn2O4(ただし、A=Mg、B、Al、Fe、Co、Ni、Cr、Zn、Ca、x=0.01~0.1)、LiNi1-xMxO2(ただし、M=Co、Fe、Ga、x=0.01~0.2)、LiFeO2、Fe2(SO4)3、LiCo1-xMxO2(ただし、M=Ni、Fe、Mn、x=0.01~0.2)、LiNi1-xMxO2(ただし、M=Mn、Fe、Co、Al、Ga、Ca、Mg、x=0.01~0.2)、Fe(MoO4)3、FeF3、LiFePO4、LiMnPO4などをなどが挙げられるが、これに限られない。
正極集電体10として、厚さが10~100μmのアルミニウム箔、あるいは厚さが10~100μm、孔径0.1~10mmの孔を有するアルミニウム製穿孔箔、エキスパンドメタル、発泡金属板などが用いられ、材質もアルミニウムの他に、ステンレス鋼、チタンなども適用可能である。二次電池の使用中に溶解、酸化などの変化をしないものであれば、材質、形状、製造方法などに制限されることなく、任意の材料を正極集電体10に使用できる。
正極活物質、正極導電剤、正極バインダ、及び有機溶媒を混合した正極スラリーを、ドクターブレード法、ディッピング法、又はスプレー法等によって正極集電体10へ付着させた後、有機溶媒を乾燥させ、ロールプレスによって加圧成形することにより、正極70を作製できる。また、塗布から乾燥までを複数回行うことにより、複数の正極合剤層40を正極集電体10に積層化させることも可能である。正極合剤層40の厚さは、正極活物質の平均粒径以上とすることが望ましい。正極合剤層40の厚さを正極活物質の平均粒径より小さくすると、隣接する正極活物質間の電子伝導性が悪化するからである。
負極活物質は、放電過程においてリチウムイオンが脱離し、充電過程において正極合剤層40中の正極活物質から脱離したリチウムイオンが挿入される。負極活物質の材料として、例えば、炭素系材料(例えば、黒鉛、易黒鉛化炭素材料、非晶質炭素材料)、導電性高分子材料(例えば、ポリアセン、ポリパラフェニレン、ポリアニリン、ポリアセチレン)、リチウム複合酸化物(例えば、チタン酸リチウム:Li4Ti5O12)、金属リチウム、リチウムと合金化する金属(例えば、アルミニウム、シリコン、スズ)を用いることができるが、これに限られない。
負極集電体20も、厚さが10~100μmの銅箔、厚さが10~100μm、孔径0.1~10mmの銅製穿孔箔、エキスパンドメタル、発泡金属板などが用いられる。銅の他に、ステンレス鋼、チタン、ニッケルなども適用できる。材質、形状、製造方法などに制限されることなく、任意の負極集電体20を使用できる。
負極活物質、負極導電剤、及び水を微量含んだ有機溶媒を混合した負極スラリーを、ドクターブレード法、ディッピング法、スプレー法等によって負極集電体20へ付着させた後、有機溶媒を乾燥させ、ロールプレスによって加圧成形することにより、負極80を作製することができる。また、塗布から乾燥までを複数回行うことにより、複数の負極合剤層60を負極集電体20に積層化させることも可能である。負極合剤層60の厚さは、負極活物質の平均粒径以上とすることが望ましい。負極合剤層60の厚さを負極活物質の平均粒径より小さくすると、隣接する負極活物質間の電子伝導性が悪化するからである。
無機粒子(粒子)としては、電気化学的安定性の観点から、絶縁性粒子であり有機溶媒またはイオン液体を含む半固体電解液に不溶であることが好ましい。例えば、シリカ(SiO2)粒子、γ-アルミナ(Al2O3)粒子、セリア(CeO2)粒子、ジルコニア(ZrO2)粒子を好ましく用いることができる。また、他の公知の金属酸化物粒子を用いてもよい。
半固体電解液は、半固体電解質溶媒、低粘度溶媒、任意の添加剤、および任意の電解質塩を有する。半固体電解質溶媒は、イオン液体に類似の性質を示すエーテル系溶媒および溶媒和電解質塩の混合物(錯体)を有する。イオン液体とは、常温でカチオンとアニオンに解離する化合物であって、液体の状態を保持するものである。イオン液体は、イオン性液体、低融点溶融塩あるいは常温溶融塩と称されることがある。半固体電解質溶媒は、大気中での安定性や二次電池内での耐熱性の観点から、低揮発性、具体的には室温における蒸気圧が150Pa以下であるものが望ましい。
半固体電解液に低粘度溶媒が含まれることにより、半固体電解液の粘度を下げられる。低粘度溶媒として、プロピレンカーボネート、エチレンカーボネート、ジメチルカーボネート等の有機溶媒や、N,N-ジエチル-N-メチル-N-(2-メトキシエチル)アンモニウムビス(トリフルオロメタンスルホニル)イミドなどのイオン液体、ハイドロフルオロエーテル類(例えば、1,1,2,2-テトラフルオロエチル-12,2,3,3-テトラフルオロプロピルエーテルなど)などを利用できる。低粘度溶媒として、エーテル系溶媒と溶媒和電解質塩との混合溶液よりも低粘度であることであることが望ましい。また、エーテル系溶媒と溶媒和電解質塩との溶媒和構造を大きく乱さないことが望ましい。具体的には、グライムもしくはクラウンエーテルなどのエーテル系溶媒とドナー数が同程度のもの、またはドナー数の小さなもの、例えば、プロピレンカーボネートや、エチレンカーボネート、アセトニトリル、ジクロロエタン、ジメチルカーボネート、1,1,2,2-テトラフルオロエチル-12,2,3,3-テトラフルオロプロピルエーテルなどを好ましく用いることができる。これらの低粘度溶媒を単独または複数組み合わせて使用してもよい。この中で、エチレンカーボネートが好ましく、プロピレンカードネートが特に好ましい。エチレンカーボネートやプロピレンカードネートは高沸点であるために、電極に低粘度溶媒が含まれていた場合に揮発しにくく、揮発による半固体電解液の組成変化の影響を受けにくい。
溶媒和電解質塩に対するエーテル系溶媒の混合比率がモル換算で0.5以上1.5以下が好ましく、0.5以上1.2以下が特に好ましく、更に0.5以上0.8以下が好ましい。上記の範囲とすることで、半固体電解液中に導入されたすべてのエーテル系溶媒が溶媒和電解質塩と溶媒和構造を形成し、電極上でのエーテル系溶媒の酸化還元分解を抑制できる。また、電解質塩に対する低粘度溶剤の混合比率がモル換算で4以上16以下が好ましく、4以上12以下が特に好ましく、更に4以上6以下が好ましい。上記の範囲とすることで、半固体電解液の粘度を十分に下げることができ、レート特性を向上できる。
前記のドナー数の条件を満たさない低粘度溶剤であっても、少量であれば添加剤として用いてもよい。半固体電解液に添加剤を含めることにより二次電池のレート特性の向上や電池寿命の向上が期待できる。添加剤の添加量は、半固体電解液の重量に対して30質量パーセント以下が好ましく、10質量パーセント以下が特に好ましい。30質量パーセントであれば、添加剤を導入してもグライム類やクラウンエーテル系溶媒と溶媒和電解質塩との溶媒和構造を大きく乱さない。添加剤として、ビニレンカーボネート、フルオロエチレンカーボネートなどを好ましく用いることができる。これらの添加剤を単独または複数組み合わせて使用してもよい。
半固体電解質バインダは、フッ素系の樹脂が好適に用いられる。フッ素系の樹脂としては、ポリテトラフルオロエチレン(PTFE)が好適に用いられる。PTFEを用いることで、半固体電解質層50と電極集電体の密着性が向上するため、電池性能が向上する。
半固体電解液が無機粒子に担持(保持)されることにより半固体電解質が構成される。半固体電解質の作製方法として、半固体電解液と無機粒子とを特定の体積比率で混合し、メタノール等の有機溶媒を添加し・混合して、半固体電解質のスラリーを調合した後、スラリーをシャーレに広げ、有機溶媒を留去して半固体電解質の粉末が得る、などが挙げられる。
半固体電解質層50の作製方法として、半固体電解質の粉末を成型ダイス等を用いてペレット状に圧縮成型する方法や、半固体電解質バインダを半固体電解質の粉末に添加・混合し、シート化する方法などがある。半固体電解質に電解質バインダの粉末を添加・混合することにより、柔軟性の高い半固体電解質層50(電解質シート)を作製できる。または、半固体電解質に、分散溶媒に半固体電解質バインダを溶解させた結着剤の溶液を添加・混合し、分散溶媒を留去することで、半固体電解質層50を作製できる。また、半固体電解質層50は、電極上に塗布および乾燥することにより作製してもよい。半固体電解質層50中の半固体電解液の含有量は70体積%以上90体積%以下であることが望ましい。半固体電解液の含有量が70体積%より大きい場合、電極と半固体電解質層50との界面抵抗が大幅に増加する可能性がある。また、半固体電解液の含有量が90%体積より大きい場合、半固体電解質層50から半固体電解液が漏れ出してしまう可能性がある。
LiTFSIとG4およびPCをモル比で1:1:4となるようにとりわけ、ガラス瓶内でマグネティックスターラを用いて撹拌、溶解させて半固体電解液を作製した。
黒鉛(非晶質被覆、平均粒径10μm)と、ポリフッ化ビニリデン(PVDF)、導電助剤(アセチレンブラック)を重量比88:10:2の割合で混合し、N-メチル-2-ピロリドンを加えてさらに混合することでスラリー状の溶液を作製した。作製したスラリーを厚さ10μmのSUS箔からなる集電体にドクターブレードを用いて塗布し、80℃で2時間以上乾燥した。このとき、乾燥後の1cm2当たりの負極合剤層60の重量が8mg/cm2となるように、スラリーの塗布量を調整した。乾燥後の電極を密度1.5g/cm3となるように加圧して、φ13mmで打ち抜いて負極80とした。
作製した負極80は、100℃で2時間以上乾燥した後に、アルゴンで充填したグローブボックス内に移した。次に、半固体電解液を負極80やポリプロピレン製で厚さ30μmのセパレータに適量加え、負極80やセパレータ中に電解液を浸透させた。その後、セパレータの片面に負極80、他面にリチウム金属を配置した状態で2032サイズのコイン型電池セルホルダに入れ、かしめ機により密閉することで実施例1の二次電池100を得た。
まず、LiTFSIとG4およびPCを混合し半固体電解液を作製した。アルゴン雰囲気のグローブボックス内で、半固体電解液とSiO2ナノ粒子(粒径7nm)を体積分率80:20で混合し、これにメタノールを添加した後に、マグネットスターラーを用いて30分間攪拌した。その後、得られた混合液をシャーレに広げ、メタノールを留去して粉末状の半固体電解質を得た。この粉末に、PTFE粉末5質量%を添加して、よく混合しながら加圧により伸ばすことで厚さ約200μmのシート状であり、LiTFSIとG4およびPCのモル比が1:1:4の半固体電解質層50を得た。
得られた半固体電解質層50はφ15mmのサイズで打ち抜いた。その後、半固体電解質層50の片面に実施例1と同様の手順で作製した負極80、他面にリチウム金属を配置した状態で2032サイズのコイン型電池セルホルダに入れ、かしめ機により密閉することで二次電池100を得た。
正極活物質LiNiMnCoO2と、ポリフッ化ビニリデン(PVDF)、導電助剤(アセチレンブラック)を重量比84:9:7の割合で混合し、N-メチル-2-ピロリドンを加えてさらに混合することでスラリー状の溶液を作製した。作製したスラリーを厚さ10μmのSUS箔からなる集電体にドクターブレードを用いて塗布し、80℃で2時間以上乾燥した。このとき、乾燥後の1cm2当たりの正極合剤層40の重量が18mg/cm2となるように、スラリーの塗布量を調整した。乾燥後の密度2.5g/cm3となるように加圧して、φ13mmで打ち抜いて正極70とした。
実施例1のリチウム金属の代わりに、本実施例の正極70を用いた以外は実施例1と同様にして二次電池100を作製した。
[比較例1]
[比較例2]
[比較例3]
[比較例4]
[比較例5]
[比較例6]
[比較例7]
[比較例8]
[比較例9]
[比較例10]
[比較例11]
[比較例12]
(1)黒鉛―リチウム金属電池
該当する実施例および比較例のコイン型の二次電池100を用いて25℃で測定した。ソーラトロン社製の1480ポテンシオスタットを用いて、0.05Cレートで充電した。その後、1時間開回路状態で休止した後に0.05Cレートで放電した。充放電時は二次電池100の電極間電位が0.005Vに達するまで0.05Cレートの一定電流で充電し、その後0.005Vの電位にて電流値が0.005Cレートに達するまで充電を行った(定電流定電圧充電)。放電時は、0.05Cレートの一定電流で1.5Vまで放電した(定電流放電)。測定結果を図4に示す。
該当する実施例のコイン型の二次電池100を用いて25℃で測定した。以下の点以外は(1)の手順と同じである。充放電時は二次電池100の電極間電位が4.2Vに達するまで0.05Cレートの一定電流で充電し、その後4.2Vの電位にて電流値が0.005Cレートに達するまで充電を行った。放電時は、0.05Cレートの一定電流で2.7Vまで放電した。測定結果を図4に示す。
実施例および比較例のコイン型の二次電池100にて実施した。前記手順にて初回充放電を実施した後に、充放電時の電流量を0.05C、0.1C、0.2C、0.3C、0.5Cレートの順に増加させて充放電を実施した。なお、充電後と放電後には、二次電池100は開回路状態で1時間休止した。測定結果を図4に示す。
二次電池100には、寿命とレート特性の高さが要求される。寿命の評価基準としては、初回充放電時のクーロン効率(放電容量と充電容量の比)が70%以上あることを条件とした。レート特性の評価基準としては、0.5Cレート(2時間で電池の設計容量を充電し終える電流値)にて容量維持率(放電容量/0.05Cレートでの放電容量×100)が90%以上あることを条件とした。電極内液量(体積%)は負極80の空隙率をもとに算出した。
20 負極集電体
30 電池ケース
40 正極合剤層
50 半固体電解質層
60 負極合剤層
70 正極
80 負極
100 二次電池
Claims (9)
- 溶媒和電解質塩と、
前記溶媒和電解質塩と溶媒和イオン液体を構成するエーテル系溶媒と、
低粘度溶媒と、を有し、
前記溶媒和電解質塩に対する前記エーテル系溶媒の混合比率がモル換算で0.5以上1.5以下であり、
前記溶媒和電解質塩に対する前記低粘度溶媒の混合比率がモル換算で4以上16以下である半固体電解液。 - 請求項1の半固体電解質において、
前記溶媒和電解質塩に対する前記低粘度溶媒の混合比率がモル換算で4以上12以下である半固体電解液。 - 請求項1の半固体電解質において、
前記溶媒和電解質塩に対する前記エーテル系溶媒の混合比率がモル換算で0.5以上1.2以下である半固体電解液。 - 請求項1の半固体電解質において、
添加剤を含む半固体電解液。 - 請求項1の半固体電解液および粒子を有し、
前記半固体電解液が前記粒子によって保持される半固体電解質。 - 請求項5の半固体電解質および半固体電解質バインダを有する半固体電解質層。
- 請求項1の半固体電解液を有する電極であって、
前記電極中の前記半固体電解液の含有量は20体積%以上40体積%以下である電極。 - 正極、負極、および請求項1の半固体電解液を有する二次電池。
- 正極、負極、および請求項6の半固体電解質層を有する二次電池。
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JP2019508754A JP6843966B2 (ja) | 2017-03-29 | 2018-02-19 | 半固体電解液、半固体電解質、半固体電解質層、電極、二次電池 |
CN201880009126.1A CN110235296A (zh) | 2017-03-29 | 2018-02-19 | 半固体电解液、半固体电解质、半固体电解质层、电极、二次电池 |
KR1020197020005A KR20190088070A (ko) | 2017-03-29 | 2018-02-19 | 반고체 전해액, 반고체 전해질, 반고체 전해질층, 전극, 이차전지 |
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JP2020087783A (ja) * | 2018-11-28 | 2020-06-04 | トヨタ自動車株式会社 | 負極 |
JP2020170656A (ja) * | 2019-04-04 | 2020-10-15 | トヨタ自動車株式会社 | 電解液およびフッ化物イオン電池 |
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JP5804557B2 (ja) | 2010-10-29 | 2015-11-04 | 国立大学法人横浜国立大学 | アルカリ金属−硫黄系二次電池 |
JP5673825B2 (ja) * | 2011-07-08 | 2015-02-18 | パナソニックIpマネジメント株式会社 | 蓄電デバイス |
CN103078136B (zh) * | 2012-12-03 | 2015-04-22 | 湖州创亚动力电池材料有限公司 | 一种低温倍率型锂离子电池电解液 |
CN103078141A (zh) * | 2013-01-25 | 2013-05-01 | 宁德新能源科技有限公司 | 锂离子二次电池及其电解液 |
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- 2018-02-19 WO PCT/JP2018/005661 patent/WO2018179990A1/ja active Application Filing
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JPH03266372A (ja) * | 1990-03-16 | 1991-11-27 | Sony Corp | リチウム二次電池 |
JP2000188128A (ja) * | 1998-12-24 | 2000-07-04 | Mitsubishi Chemicals Corp | 非水電解液二次電池 |
JP2002298916A (ja) * | 2001-03-28 | 2002-10-11 | Osaka Gas Co Ltd | 非水系二次電池 |
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JP2020087783A (ja) * | 2018-11-28 | 2020-06-04 | トヨタ自動車株式会社 | 負極 |
JP7077923B2 (ja) | 2018-11-28 | 2022-05-31 | トヨタ自動車株式会社 | 負極 |
JP2020170656A (ja) * | 2019-04-04 | 2020-10-15 | トヨタ自動車株式会社 | 電解液およびフッ化物イオン電池 |
JP7201514B2 (ja) | 2019-04-04 | 2023-01-10 | トヨタ自動車株式会社 | 電解液およびフッ化物イオン電池 |
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US20200014067A1 (en) | 2020-01-09 |
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