WO2017204028A1 - 固体電解質組成物、固体電解質含有シートおよび全固体二次電池ならびに固体電解質含有シートおよび全固体二次電池の製造方法 - Google Patents
固体電解質組成物、固体電解質含有シートおよび全固体二次電池ならびに固体電解質含有シートおよび全固体二次電池の製造方法 Download PDFInfo
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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
- H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
- H01M10/0562—Solid materials
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
- H01B1/10—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances sulfides
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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
- H01M10/058—Construction or manufacture
- H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
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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
- H01M4/621—Binders
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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
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0065—Solid electrolytes
- H01M2300/0068—Solid electrolytes inorganic
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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
- H01M2300/0065—Solid electrolytes
- H01M2300/0068—Solid electrolytes inorganic
- H01M2300/0071—Oxides
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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
- H01M2300/0088—Composites
- H01M2300/0091—Composites in the form of mixtures
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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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- 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
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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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates to a solid electrolyte composition, a solid electrolyte-containing sheet and an all-solid secondary battery, and a method for producing a solid electrolyte-containing sheet and an all-solid secondary battery.
- a lithium ion secondary battery is a storage battery that has a negative electrode, a positive electrode, and an electrolyte sandwiched between the negative electrode and the positive electrode, and enables charging and discharging by reciprocating lithium ions between the two electrodes.
- an organic electrolytic solution has been used as an electrolyte in a lithium ion secondary battery.
- the organic electrolyte is liable to leak, and there is a possibility that a short circuit occurs inside the battery due to overcharge or overdischarge, resulting in ignition, and further improvements in reliability and safety are required. Under such circumstances, an all-solid secondary battery using an inorganic solid electrolyte instead of an organic electrolyte has been attracting attention.
- All-solid-state secondary batteries are composed of a solid negative electrode, electrolyte, and positive electrode, which can greatly improve safety and reliability, which is a problem of batteries using organic electrolytes, and can also extend the life. It will be. Furthermore, the all-solid-state secondary battery can have a structure in which electrodes and an electrolyte are directly arranged in series. Therefore, it is possible to increase the energy density as compared with a secondary battery using an organic electrolyte, and application to an electric vehicle, a large storage battery, and the like is expected.
- all-solid-state secondary batteries are being developed as next-generation lithium-ion batteries.
- an active material layer of a negative electrode, a solid electrolyte layer, and an active material layer of a positive electrode are usually combined with an inorganic solid electrolyte and / or an active material and a binder (a binder such as a specific polymer compound). It is formed using the material containing (adhesive).
- Patent Document 1 describes that the battery resistance is reduced by configuring the solid electrolyte layer of the all-solid-state secondary battery to include a specific sulfide solid electrolyte material and a hydrophobic polymer. Yes.
- Patent Document 2 an inorganic solid electrolyte and a binder made of a particulate polymer containing a surfactant having a polyoxyethylene chain are used in combination in a layer constituting an all-solid secondary battery.
- a binder made of a particulate polymer containing a surfactant having a polyoxyethylene chain are used in combination in a layer constituting an all-solid secondary battery.
- the battery voltage of the obtained all-solid-state secondary battery can be sufficiently increased, and the layer thickness uniformity is also increased, so that short circuits and the like are less likely to occur. It is an object to provide a solid electrolyte composition.
- the present invention uses a solid electrolyte-containing sheet having a uniform layer thickness, excellent ionic conductivity, and capable of effectively increasing battery voltage when used in an all-solid secondary battery, and the sheet.
- An object is to provide an all-solid-state secondary battery.
- this invention makes it a subject to provide the manufacturing method of each of the said solid electrolyte containing sheet
- a dispersion medium having a specific chemical structure and having a boiling point within a predetermined range at normal pressure, a specific inorganic solid electrolyte, and a binder are contained.
- the solid electrolyte composition has excellent dispersion stability and has a viscosity suitable for battery production, and the layer thickness can be made more uniform by forming a layer using the solid electrolyte composition. It has been found that the all-solid-state secondary battery has a sufficiently high battery voltage.
- the present invention has been further studied based on these findings and has been completed.
- the dispersion medium (C) contains an alicyclic compound (C1) composed of carbon atoms and hydrogen atoms and / or halogen atoms, and the boiling point of the alicyclic compound (C1) at 760 mmHg is 100 ° C. or higher and 180 ° C.
- a solid electrolyte composition which is: (2) The solid electrolyte composition according to (1), wherein the alicyclic compound (C1) does not contain an unsaturated bond in the ring and is monocyclic. (3) The alicyclic compound (C1) has at least one selected from the group consisting of an alkyl group having 2 or more carbon atoms, an alkenyl group, an alkynyl group, and a halogen atom, according to (1) or (2) Solid electrolyte composition. (4) The solid electrolyte composition according to any one of (1) to (3), wherein the alicyclic compound (C1) is a 6- to 8-membered ring compound.
- the binder (B) is at least one selected from the group consisting of acrylic resin, polyurethane resin, polyurea resin, polyimide resin, fluorine-containing resin and hydrocarbon-based thermoplastic resin (1) to (6) Solid electrolyte composition as described in any one of these.
- (15) Contains an inorganic solid electrolyte (A) having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table and a binder (B), and the dispersion medium (C) is 1 ppm or more in the total mass.
- a method for producing a solid electrolyte-containing sheet comprising a step of applying the solid electrolyte composition according to any one of (1) to (14) on a substrate to form a coating film.
- An all-solid secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, An all-solid secondary battery, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is the solid electrolyte-containing sheet according to (15).
- a method for producing an all-solid secondary battery wherein an all-solid secondary battery is produced via the production method according to (16).
- a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
- acryl or “(meth) acryl” is simply described, it means methacryl and / or acryl.
- the term “acryloyl” or “(meth) acryloyl” simply means methacryloyl and / or acryloyl.
- substituents, etc. when there are a plurality of substituents, linking groups, etc. (hereinafter referred to as substituents, etc.) indicated by specific symbols, or when a plurality of substituents etc. are specified simultaneously or alternatively, It means that a substituent etc. may mutually be same or different. The same applies to the definition of the number of substituents and the like.
- the mass average molecular weight (Mw) can be measured as a molecular weight in terms of polystyrene by GPC.
- GPC device HLC-8220 manufactured by Tosoh Corporation
- G3000HXL + G2000HXL is used as the column
- the flow rate is 1 mL / min at 23 ° C.
- detection is performed by RI.
- the eluent can be selected from THF (tetrahydrofuran), chloroform, NMP (N-methyl-2-pyrrolidone), m-cresol / chloroform (manufactured by Shonan Wako Pure Chemical Industries, Ltd.) and dissolves. If present, use THF.
- the solid electrolyte composition of the present invention is excellent in dispersion stability and has a viscosity suitable for battery production.
- the solid electrolyte-containing sheet of the present invention has a highly uniform layer thickness and is excellent in ion conductivity. Further, the all solid state secondary battery of the present invention can realize a sufficiently high battery voltage. Moreover, according to the manufacturing method of this invention, the solid electrolyte containing sheet
- FIG. 1 is a longitudinal sectional view schematically showing an all solid state secondary battery according to a preferred embodiment of the present invention.
- FIG. 2 is a longitudinal sectional view schematically showing the test apparatus used in the examples.
- FIG. 3 is a longitudinal sectional view schematically showing an all solid state secondary battery (coin battery) produced in the example.
- FIG. 1 is a cross-sectional view schematically showing an all solid state secondary battery (lithium ion secondary battery) according to a preferred embodiment of the present invention.
- the all-solid-state secondary battery 10 of this embodiment has a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in this order as viewed from the negative electrode side. .
- Each layer is in contact with each other and has a laminated structure.
- the solid electrolyte composition of the present invention can be preferably used as a molding material for the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer.
- the solid electrolyte-containing sheet of the present invention is suitable as the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer.
- a positive electrode active material layer (hereinafter also referred to as a positive electrode layer) and a negative electrode active material layer (hereinafter also referred to as a negative electrode layer) may be collectively referred to as an electrode layer or an active material layer.
- the all-solid-state secondary battery having the layer configuration shown in FIG. 1 when putting the all-solid-state secondary battery having the layer configuration shown in FIG. 1 into a 2032 type coin case, the all-solid-state secondary battery having the layer configuration shown in FIG. A battery produced by placing an electrode sheet for an all-solid secondary battery in a 2032 type coin case may be referred to as an all-solid secondary battery.
- the thicknesses of the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 are not particularly limited. In consideration of general battery dimensions, the thickness is preferably 10 to 1,000 ⁇ m, more preferably 20 ⁇ m or more and less than 500 ⁇ m. In the all solid state secondary battery of the present invention, it is more preferable that the thickness of at least one of the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 is 50 ⁇ m or more and less than 500 ⁇ m.
- the solid electrolyte composition of the present invention comprises an inorganic solid electrolyte (A) having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, a binder (B), and a dispersion medium (C). contains.
- the dispersion medium (C) contains the alicyclic compound (C1), and the boiling point of the alicyclic compound (C1) at 760 mmHg is 100 ° C. or higher and 180 ° C. or lower.
- the inorganic solid electrolyte (A), the binder (B), and the dispersion medium (C) may be referred to as an inorganic solid electrolyte, a binder, and a dispersion medium, respectively.
- the inorganic solid electrolyte is an inorganic solid electrolyte, and the solid electrolyte is a solid electrolyte capable of moving ions inside. Since it does not contain organic substances as the main ion conductive material, organic solid electrolytes (polymer electrolytes typified by polyethylene oxide (PEO), etc., organics typified by lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), etc. It is clearly distinguished from the electrolyte salt). In addition, since the inorganic solid electrolyte is solid in a steady state, it is not usually dissociated or released into cations and anions.
- organic solid electrolytes polymer electrolytes typified by polyethylene oxide (PEO), etc.
- LiTFSI lithium bis (trifluoromethanesulfonyl) imide
- inorganic electrolyte salts LiPF 6 , LiBF 4 , LiFSI, LiCl, etc.
- the inorganic solid electrolyte is not particularly limited as long as it has conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table, and generally does not have electron conductivity.
- the inorganic solid electrolyte has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table.
- a solid electrolyte material applied to this type of product can be appropriately selected and used.
- Typical examples of inorganic solid electrolytes include (i) sulfide-based inorganic solid electrolytes and (ii) oxide-based inorganic solid electrolytes.
- a sulfide-based inorganic solid electrolyte is preferably used.
- the sulfide-based inorganic solid electrolyte contains a sulfur atom (S) and has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and Those having electronic insulating properties are preferred.
- the sulfide-based inorganic solid electrolyte preferably contains at least Li, S and P as elements and has lithium ion conductivity. However, depending on the purpose or the case, other than Li, S and P may be used. An element may be included. For example, a lithium ion conductive inorganic solid electrolyte that satisfies the composition represented by the following formula (1) can be given.
- L represents an element selected from Li, Na and K, and Li is preferred.
- M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge.
- A represents an element selected from I, Br, Cl and F.
- a1 to e1 indicate the composition ratio of each element, and a1: b1: c1: d1: e1 satisfies 1 to 12: 0 to 5: 1: 2 to 12: 0 to 10.
- a1 is further preferably 1 to 9, and more preferably 1.5 to 7.5.
- b1 is preferably 0 to 3.
- d1 is preferably 2.5 to 10, and more preferably 3.0 to 8.5.
- e1 is preferably 0 to 5, and more preferably 0 to 3.
- composition ratio of each element can be controlled by adjusting the blending amount of the raw material compound when producing the sulfide-based solid electrolyte as described below.
- the sulfide-based inorganic solid electrolyte may be amorphous (glass) or crystallized (glass ceramic), or only a part may be crystallized.
- a Li—PS system glass containing Li, P and S, or a Li—PS system glass ceramic containing Li, P and S can be used.
- the sulfide-based inorganic solid electrolyte includes, for example, lithium sulfide (Li 2 S), phosphorus sulfide (for example, diphosphorus pentasulfide (P 2 S 5 )), simple phosphorus, simple sulfur, sodium sulfide, hydrogen sulfide, lithium halide (for example, LiI, LiBr, LiCl) and a sulfide of an element represented by M (for example, SiS 2 , SnS, GeS 2 ) can be produced by reaction of at least two raw materials.
- Li 2 S lithium sulfide
- P 2 S 5 diphosphorus pentasulfide
- simple phosphorus simple sulfur
- sodium sulfide sodium sulfide
- hydrogen sulfide lithium halide
- a sulfide of an element represented by M for example, SiS 2 , SnS, GeS 2
- the ratio of Li 2 S and P 2 S 5 in the Li—PS system glass and Li—PS system glass ceramic is a molar ratio of Li 2 S: P 2 S 5 , preferably 60:40 to 90:10, more preferably 68:32 to 78:22.
- the lithium ion conductivity can be increased.
- the lithium ion conductivity can be preferably 1 ⁇ 10 ⁇ 4 S / cm or more, more preferably 1 ⁇ 10 ⁇ 3 S / cm or more. Although there is no particular upper limit, it is practical that it is 1 ⁇ 10 ⁇ 1 S / cm or less.
- Li 2 S—P 2 S 5 Li 2 S—P 2 S 5 —LiCl, Li 2 S—P 2 S 5 —H 2 S, Li 2 S—P 2 S 5 —H 2 S—LiCl, Li 2 S—LiI—P 2 S 5 , Li 2 S—LiI—Li 2 O—P 2 S 5 , Li 2 S—LiBr—P 2 S 5 , Li 2 S—Li 2 O—P 2 S 5 , Li 2 S—Li 3 PO 4 —P 2 S 5 , Li 2 S—P 2 S 5 —P 2 O 5 , Li 2 S—P 2 S 5 —SiS 2 , Li 2 S—P 2 S 5 —SiS 2 —LiCl, Li 2 S—P 2 S 5 —SnS, Li 2 S—P 2 S 5 —Al 2 S 3 , Li 2
- Examples of a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition include an amorphization method.
- Examples of the amorphization method include a mechanical milling method, a solution method, and a melt quench method. This is because processing at room temperature is possible, and the manufacturing process can be simplified.
- Oxide-based inorganic solid electrolyte contains an oxygen atom (O) and has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and A compound having an electronic insulating property is preferable.
- Li xc B yc M cc zc Onc (M cc is C, S, Al, Si, Ga, Ge, In, Sn are at least one element, xc satisfies 0 ⁇ xc ⁇ 5, yc satisfies 0 ⁇ yc ⁇ 1, and zc satisfies 0 ⁇ zc ⁇ met 1, nc satisfies 0 ⁇ nc ⁇ 6.), Li xd ( l, Ga) yd (Ti, Ge) zd Si ad P md O nd ( provided that, 1 ⁇ xd ⁇ 3,0 ⁇ yd ⁇ 1,0 ⁇ zd ⁇ 2,0 ⁇ ad ⁇ 1,1 ⁇ md
- D ee represents a halogen atom or Represents a combination of two or more halogen atoms.
- Li 3 BO 3 —Li 2 SO 4 Li 2 O—B 2 O 3 —P 2 O 5 , Li 2 O—SiO 2 , Li 6 BaLa 2 ta 2 O 12, Li 3 PO (4-3 / 2w) N w (w is w ⁇ 1), LI ICON (Lithium super ionic conductor) type Li 3.5 Zn 0.25 GeO 4 having a crystal structure, La 0.55 Li 0.35 TiO 3 having a perovskite crystal structure, NASICON (Natrium super ionic conductor) type crystal structure
- Li, P and O Phosphorus compounds containing Li, P and O are also desirable.
- lithium phosphate Li 3 PO 4
- LiPON obtained by replacing a part of oxygen of lithium phosphate with nitrogen
- LiPOD 1 LiPOD 1
- LiA 1 ON A 1 is at least one selected from Si, B, Ge, Al, C, Ga, etc.
- the shape of the inorganic solid electrolyte before being contained in the solid electrolyte composition is not particularly limited, but is preferably in the form of particles.
- the volume average particle diameter of the inorganic solid electrolyte before being contained in the solid electrolyte composition is not particularly limited, but is preferably 0.01 ⁇ m or more, and more preferably 0.1 ⁇ m or more. As an upper limit, it is preferable that it is 100 micrometers or less, and it is more preferable that it is 50 micrometers or less.
- the volume average particle diameter of the inorganic solid electrolyte before being contained in the solid electrolyte composition can be calculated by the method described in the section of Examples described later.
- the shape of the inorganic solid electrolyte in the solid electrolyte composition is not particularly limited, but is preferably particulate.
- the volume average particle diameter of the inorganic solid electrolyte in the solid electrolyte composition is not particularly limited, but it is preferably as small as possible.
- the smaller the volume average particle size of the inorganic solid electrolyte the larger the surface contact area between the inorganic solid electrolyte and the active material. As a result, lithium ions can easily move in and between layers constituting the all-solid-state secondary battery. It is practical that the lower limit of the volume average particle diameter of the inorganic solid electrolyte is 0.1 ⁇ m or more.
- the upper limit of the volume average particle diameter of the inorganic solid electrolyte is preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less, and particularly preferably 2 ⁇ m or less.
- the volume average particle diameter of the inorganic solid electrolyte in the solid electrolyte composition can be calculated by the method described in the section of Examples described later.
- the content of the solid component in the solid electrolyte composition of the inorganic solid electrolyte is 100% by mass of the solid component when considering the reduction of the interface resistance when used in an all-solid secondary battery and the maintenance of the reduced interface resistance. It is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 20% by mass or more. As an upper limit, it is preferable that it is 99.9 mass% or less from the same viewpoint, It is more preferable that it is 99.5 mass% or less, It is especially preferable that it is 99 mass% or less.
- the said inorganic solid electrolyte may be used individually by 1 type, or may be used in combination of 2 or more type.
- solid content refers to a component that does not volatilize or evaporate when subjected to a drying treatment at 170 ° C. for 6 hours in a nitrogen atmosphere. Typically, it refers to components other than the dispersion medium described below.
- the solid electrolyte composition of the present invention contains a binder (B).
- the binder used in the present invention is not particularly limited as long as it is an organic polymer.
- the binder that can be used in the present invention is not particularly limited, and for example, a binder made of the resin described below is preferable.
- fluorine-containing resin examples include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP).
- hydrocarbon-based thermoplastic resin examples include polyethylene, polypropylene, styrene butadiene rubber (SBR), hydrogenated styrene butadiene rubber (HSBR), butylene rubber, acrylonitrile butadiene rubber, polybutadiene, and polyisoprene.
- acrylic resin examples include various (meth) acrylic monomers, (meth) acrylamide monomers, and copolymers of these monomers (preferably a copolymer of acrylic acid and methyl acrylate). It is done. Further, a copolymer (copolymer) with other vinyl monomers is also preferably used. Examples thereof include a copolymer of methyl (meth) acrylate and styrene, a copolymer of methyl (meth) acrylate and acrylonitrile, and a copolymer of butyl (meth) acrylate, acrylonitrile, and styrene.
- the copolymer may be any of a statistical copolymer, a periodic copolymer, a block copolymer, and a graft copolymer, and a block copolymer is preferable.
- other resins include polyurethane resin, polyurea resin, polyamide resin, polyimide resin, polyester resin, polyether resin, polycarbonate resin, and cellulose derivative resin. These may be used individually by 1 type, or may be used in combination of 2 or more type.
- the binder used in the present invention is the above-mentioned acrylic resin, polyurethane resin, polyurea resin, polyimide resin, fluorine-containing resin, and the like in order to further improve the bonding between the inorganic solid electrolyte particles and between the inorganic solid electrolyte particles and the active material particles. It is preferably at least one selected from the group consisting of hydrocarbon-based thermoplastic resins.
- the binder used in the present invention preferably has a polar group in order to improve wettability and adsorptivity to the particle surface.
- the polar group is preferably a monovalent group containing a hetero atom, for example, a monovalent group containing a structure in which any one of an oxygen atom, a nitrogen atom and a sulfur atom is bonded to a hydrogen atom.
- Specific examples include a carboxy group, A hydroxy group, an amino group, a phosphate group, and a sulfo group are mentioned.
- the shape of the binder is not particularly limited, and may be particulate or indefinite in the solid electrolyte composition, the solid electrolyte-containing sheet, or the all-solid secondary battery.
- the binder is particles insoluble in the dispersion medium.
- “the binder is an insoluble particle in the dispersion medium” means that the average particle diameter does not decrease by 5% or more even when added to the dispersion medium at 30 ° C. and left to stand for 24 hours. It is preferably 3% or less, more preferably 1% or less.
- the binder in the solid electrolyte composition is preferably a nanoparticle having an average particle diameter of 10 to 1000 nm in order to suppress a decrease in interparticle ion conductivity of the inorganic solid electrolyte.
- the average particle size of the binder can be calculated by the method described in the Examples section below.
- the binder may be composed of one compound or a combination of two or more compounds.
- the binder is a particle, the particle itself may not be a uniform dispersion but may be a core-shell shape or a hollow shape.
- you may enclose organic substance and an inorganic substance in the core part which forms the inside of a binder.
- the organic substance included in the core include a dispersion medium, a dispersant, a lithium salt, an ionic liquid, and a conductive auxiliary agent described later.
- a commercial item can be used for the binder used for this invention. Moreover, it can also prepare by a conventional method.
- the water concentration of the polymer constituting the binder used in the present invention is preferably 100 ppm (mass basis) or less.
- the polymer which comprises the binder used for this invention may be used in a solid state, and may be used in the state of a polymer particle dispersion or a polymer solution.
- the mass average molecular weight of the polymer constituting the binder used in the present invention is preferably 10,000 or more, more preferably 20,000 or more, and further preferably 30,000 or more. As an upper limit, 1,000,000 or less is preferable, 200,000 or less is more preferable, and 100,000 or less is more preferable.
- the content of the binder in the solid electrolyte composition is 0.01% by mass with respect to 100% by mass of the solid component, considering good reduction in interface resistance and its maintainability when used in an all-solid secondary battery.
- the above is preferable, 0.1% by mass or more is more preferable, and 1% by mass or more is more preferable.
- the mass ratio of the total mass (total amount) of the inorganic solid electrolyte and the active material to the mass of the binder [(mass of the inorganic solid electrolyte + mass of the active material) / mass of the binder] is 1,000 to 1. A range is preferred. This ratio is more preferably 500 to 2, and further preferably 100 to 10.
- the dispersion medium of the present invention contains an alicyclic compound (C1).
- the alicyclic compound (C1) has a boiling point of 100 ° C. or more and 180 ° C. or less at normal pressure (760 mmHg), and is not particularly limited as long as it is a compound composed of specific atoms as described later. The reason is not clear, but in the present invention, the dispersion medium contains the alicyclic compound (C1), so that the solid electrolyte composition as a slurry is not only excellent in dispersion stability but also suitable for battery production. Has viscosity.
- the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer can be formed to have a uniform thickness, and a predetermined amount of the dispersion medium is removed by drying at a low temperature. be able to. Also in each layer, it is considered that the solid component is uniformly dispersed as in the solid electrolyte composition, which is considered to contribute to the improvement of the voltage of the all-solid secondary battery.
- miniaturized can be disperse
- the reason for this is not clear, but is estimated as follows. That is, when the dispersion medium contains an alicyclic compound, when preparing the solid electrolyte composition, the energy for miniaturizing the inorganic solid electrolyte (for example, the rotational energy of the ball when using a ball mill) is sufficiently inorganic. It is considered that the inorganic solid electrolyte can be sufficiently miniaturized because it is transmitted to the solid electrolyte. Furthermore, since the inorganic solid electrolyte is stable with respect to the alicyclic compound, it is considered that dissolution and decomposition of the inorganic solid electrolyte are suppressed, and the decrease in ionic conductivity can be minimized.
- the lower limit of the boiling point of the alicyclic compound (C1) is preferably 110 ° C. or higher, more preferably 120 ° C. or higher.
- the upper limit is preferably 160 ° C. or lower, and more preferably 150 ° C. or lower.
- the alicyclic compound (C1) does not contain heteroatoms other than halogen atoms. Since the atoms constituting the alicyclic compound (C1) used in the present invention are only carbon and hydrogen atoms, only carbon and halogen atoms, or only carbon, hydrogen and halogen atoms, alicyclic compounds The solubility of the inorganic solid electrolyte in (C1) is low, and the reaction with the inorganic solid electrolyte hardly occurs.
- the alicyclic compound (C1) does not contain an unsaturated bond in the ring and is monocyclic.
- the alicyclic compound (C1) may have a substituent or may be unsubstituted.
- substituent include the substituent P described later.
- the alicyclic compound (C1) is a group consisting of an alkyl group (preferably an alkyl group having 2 or more carbon atoms), an alkenyl group, an alkynyl group and a halogen atom. It is preferable to have at least one selected from the group consisting of an alkyl group and a halogen atom.
- an alkyl group having 2 to 6 carbon atoms is preferable, and more preferably 2 to 4 carbon atoms.
- an alkyl group having 2 to 6 carbon atoms is preferable, and more preferably 2 to 4 carbon atoms.
- an alkynyl group having 2 to 6 carbon atoms is preferable, and more preferably 2 to 4 carbon atoms.
- a chlorine atom is more preferable.
- the substituent of the alicyclic compound (C1) has a branched structure because it is easily available.
- the alicyclic compound (C1) is a 6- to 8-membered ring compound because a slurry viscosity which is more excellent in coating production suitability is obtained.
- alicyclic compound (C1) examples include the following compounds. However, the present invention is not limited to these.
- the unsubstituted compound examples include cycloheptane (bp 118 ° C., “bp” is a notation in which the boiling point “boiling point” is omitted, the same applies hereinafter), cyclooctane (bp 149 ° C.), cyclononane (bp 178 ° C.), and the like.
- Examples of the compound having an alkyl group include ethylcyclopentane (bp103 ° C), methylcyclohexane (bp101 ° C), 1,3,5-trimethylcyclohexane (bp140 ° C), ethylcyclohexane (bp131 ° C), propylcyclohexane (bp155 ° C), Examples thereof include isopropylcyclohexane (bp 155 ° C.), 1-methyl-4-isopropylcyclohexane (bp 171 ° C.), isobutyl cyclohexane (bp 169 ° C.), t-butyl cyclohexane (bp 167 ° C.), butyl cyclohexane (bp 180 ° C.) and the like.
- Examples of the compound having an alkenyl group include vinylcyclopentane (bp 100 ° C.) and vinyl cyclohexane (bp 121 ° C.).
- Examples of the compound having an alkynyl group include ethynylcyclopentane (bp 105 ° C.) and ethynyl cyclohexane (bp 118 ° C.).
- the compounds having a halogen atom include chlorocyclopentane (bp 114 ° C.), bromocyclopentane (bp 138 ° C.), fluorocyclohexane (bp 103 ° C.), chlorocyclohexane (bp 142 ° C.), bromocyclohexane (bp 166 ° C.), chlorocycloheptane (bp 175). ° C) and the like.
- Examples of the compound having an unsaturated bond in the ring include 1-methyl-1-cyclohexene (bp 110 ° C.), 3-methyl-1-cyclohexene (bp 104 ° C.), 4-methyl-1-cyclohexene (bp 102 ° C.), 1- Examples thereof include methyl-1,4-cyclohexadiene (bp 115 ° C.), vinylcyclohexene (bp 126 ° C.), cyclooctene (bp 145 ° C.), cyclooctadiene (bp 151 ° C.), and the like.
- polycyclic having two or more rings in one molecule
- examples of polycyclic include norbornane (bp 106 ° C.), camphene (bp 159 ° C.), 5-vinyl-2-norbornene (bp 141 ° C.), 5-ethylidene-2-norbornene (Bp 147 ° C.), 5,6-dihydrodicyclopentadiene (bp 180 ° C.) and the like.
- An alicyclic compound (C1) may be used individually by 1 type, and 2 or more types may be mixed and used for it.
- the lower limit of the viscosity of the alicyclic compound (C1) at 20 ° C. is preferably 0.7 mPa ⁇ s or more, more preferably 0.8 mPa ⁇ s or more, and particularly preferably 1.0 mPa ⁇ s or more.
- an upper limit is not specifically limited, 10 mPa * s or less is preferable, 5.0 mPa * s or less is more preferable, and 3.0 mPa * s or less is especially preferable.
- the viscosity is within the above range, the solid electrolyte composition as a slurry is more excellent in dispersion stability and the layer thickness uniformity of a layer obtained by applying the solid electrolyte composition to a substrate is also excellent.
- the lower limit of the viscosity of the solid electrolyte composition of the present invention at 20 ° C. is preferably 30 mPa ⁇ s or more, more preferably 50 mPa ⁇ s or more, and particularly preferably 100 mPa ⁇ s or more.
- an upper limit is not specifically limited, 10000 mPa * s or less is preferable, 1000 mPa * s or less is more preferable, 500 mPa * s or less is especially preferable.
- a dispersion medium other than the alicyclic compound (C1) (amide solvent, amine solvent, alcohol solvent (for example, methanol, ethanol, butanol, pen) (Tanol and hexanol), ether solvents (eg, diethoxyethane, dibutyl ether, tetraethylene glycol dimethyl ether (tetraglyme), triethylene glycol dimethyl ether (triglyme), tetraethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol and Triethylene glycol), ester solvents (eg butyl butyrate and ⁇ -butyrolactone), carbonate solvents (eg ethylene carbonate, dimethyl carbonate and diethyl carbonate) Bonate), cyclic ether solvent, ketone solvent (eg, methyl ethyl ketone), sulfonyl solvent, hydrocarbon solvent
- the dispersion medium preferably contains 20% by mass or more of the alicyclic compound (C1), more preferably 50% by mass or more, further preferably 80% by mass or more, and particularly preferably 95% by mass or more.
- the content is within the above range, the solid electrolyte composition that is a slurry is more excellent in dispersion stability, and the layer thickness of the layer obtained by applying the solid electrolyte composition to the substrate also depends on the layer thickness uniformity. It is because it is excellent.
- the dispersion medium (C) contained in the solid electrolyte composition is removed in a specific amount in the production process of the solid electrolyte-containing sheet or the all-solid secondary battery.
- the solid electrolyte-containing sheet of the present invention contains the dispersion medium (C) in a total mass of 1 ppm to 10000 ppm.
- the upper limit of the content (mass basis) of the dispersion medium (C) in the solid electrolyte-containing sheet of the present invention is preferably 1000 ppm or less, and more preferably 500 ppm or less.
- the content of the dispersion medium in the solid electrolyte composition can be appropriately set in consideration of the balance between the viscosity of the solid electrolyte composition and the drying load. Generally, it is preferably 20 to 99% by mass, more preferably 25 to 90% by mass, and particularly preferably 30 to 80% by mass in the solid electrolyte composition.
- a compound or group for which substitution or non-substitution is not specified clearly means that the compound or group may have an appropriate substituent. This is also synonymous for compounds that do not specify substituted or unsubstituted.
- Preferable substituents include the following substituent P. Examples of the substituent P include the following.
- alkyl group preferably an alkyl group having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.
- alkenyl A group preferably an alkenyl group having 2 to 20 carbon atoms such as vinyl, allyl, oleyl and the like
- an alkynyl group preferably an alkynyl group having 2 to 20 carbon atoms such as ethynyl, butadiynyl, phenylethynyl and the like
- a cycloalkyl group preferably a cycloalkyl group having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc., but in this specification,
- an aryloyl group (preferably an aryloyl group having 7 to 23 carbon atoms, such as benzoyl, etc., but an acyl group in this specification usually means an aryloyl group).
- An acyloxy group (preferably an acyloxy group having 1 to 20 carbon atoms, such as acetyloxy), an aryloyloxy group (preferably an aryloyloxy group having 7 to 23 carbon atoms, such as benzoyloxy, etc., provided that In this specification, an acyloxy group usually means an aryloyloxy group), a carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, such as N, N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.
- An acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.), an alkylsulfanyl group (preferably an alkylsulfanyl group having 1 to 20 carbon atoms, such as methylsulfanyl, ethyl Sulfanyl, isopropyl Sulfanyl, benzylsulfanyl, etc.), arylsulfanyl groups (preferably arylsulfanyl groups having 6 to 26 carbon atoms, such as phenylsulfanyl, 1-naphthylsulfanyl, 3-methylphenylsulfanyl, 4-methoxyphenylsulfanyl, etc.), alkylsulfonyl A group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms, such as methylsulfonyl or ethyls
- a silyl group (preferably an alkylsilyl group having 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), an arylsilyl group (preferably 6 to 4 carbon atoms)
- Arylsilyl groups such as triphenylsilyl
- alkoxysilyl groups preferably alkoxysilyl groups having 1 to 20 carbon atoms such as monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.
- aryl An oxysilyl group (preferably an aryloxysilyl group having 6 to 42 carbon atoms, such as triphenyloxysilyl), a phosphoryl group (preferably a phosphoryl group having 0 to 20 carbon atoms, such as —OP ( ⁇ O) (R P ) 2 ), a phosphonyl group (preferably a phosphonyl
- Groups such as -P (R P ) 2 ), (meth) acryloyl groups, (meth) acryloyloxy groups, ( (Meth) acryloylumimino group ((meth) acrylamide group), hydroxy group, sulfanyl group, carboxy group, phosphoric acid group, phosphonic acid group, sulfonic acid group, cyano group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, Iodine atom).
- each of the groups listed as the substituent P may be further substituted with the substituent P described above.
- substituent, linking group and the like include an alkyl group, an alkylene group, an alkenyl group, an alkenylene group, an alkynyl group and / or an alkynylene group, these may be cyclic or linear, and may be linear or branched. It may be substituted as described above or unsubstituted.
- the solid electrolyte composition of the present invention may contain a dispersant. Even when the concentration of either the electrode active material or the inorganic solid electrolyte is high by adding a dispersant, or even when the particle diameter is small and the surface area is increased, the aggregation is suppressed, and the uniform active material layer and solid electrolyte layer Can be formed.
- a dispersant those usually used for all-solid secondary batteries can be appropriately selected and used. In general, compounds intended for particle adsorption and steric repulsion and / or electrostatic repulsion are preferably used.
- the solid electrolyte composition of the present invention may contain a lithium salt.
- the lithium salt that can be used in the present invention is preferably a lithium salt that is usually used for this type of product, and is not particularly limited. For example, the following are preferable.
- Inorganic lithium salts inorganic fluoride salts such as LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 ; perhalogenates such as LiClO 4 , LiBrO 4 , LiIO 4 ; inorganic chloride salts such as LiAlCl 4 etc.
- (L-3) Oxalatoborate salt lithium bis (oxalato) borate, lithium difluorooxalatoborate and the like.
- Rf 1 and Rf 2 each represent a perfluoroalkyl group.
- lithium salt may be used individually by 1 type, or may combine 2 or more types arbitrarily.
- the lithium salt content is preferably 0.1 parts by mass or more, and more preferably 0.5 parts by mass or more with respect to 100 parts by mass of the inorganic solid electrolyte.
- 10 mass parts or less are preferable, and 5 mass parts or less are more preferable.
- the solid electrolyte composition of the present invention may contain an ionic liquid in order to further improve the ionic conductivity of the solid electrolyte-containing sheet.
- an ionic liquid From the viewpoint of improving an ionic conductivity effectively, what melt
- the compound which consists of a combination of the following cation and an anion is mentioned.
- (I) Cation As a cation, an imidazolium cation having the following substituent, a pyridinium cation having the following substituent, a piperidinium cation having the following substituent, a pyrrolidinium cation having the following substituent, Morpholinium cations having the following substituents, phosphonium cations having the following substituents, or quaternary ammonium cations having the following substituents. As the cation, one kind of these cations may be used alone, or two or more kinds may be used in combination. Preferably, it is a quaternary ammonium cation, a piperidinium cation or a pyrrolidinium cation.
- an alkyl group (an alkyl group having 1 to 8 carbon atoms is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable), a hydroxyalkyl group (a hydroxyalkyl group having 1 to 3 carbon atoms is preferable).
- An alkyloxyalkyl group (preferably an alkyloxyalkyl group having 2 to 8 carbon atoms, more preferably an alkyloxyalkyl group having 2 to 4 carbon atoms), an ether group, an allyl group, an aminoalkyl group (1 to 8 carbon atoms).
- an aryl group (an aryl group having 6 to 12 carbon atoms is more preferable, and an aryl group having 6 to 8 carbon atoms is more preferable).
- the substituent may form a cyclic structure containing a cation moiety. These substituents may further have the above substituent P.
- the ether group is used in combination with other substituents. Examples of such a substituent include an alkyloxy group and an aryloxy group.
- Anions As anions, chloride ions, bromide ions, iodide ions, boron tetrafluoride ions, nitrate ions, dicyanamide ions, acetate ions, iron tetrachloride ions, bis (trifluoromethanesulfonyl) imide ions, bis ( Fluorosulfonyl) imide ion, bis (perfluorobutylmethanesulfonyl) imide ion, allyl sulfonate ion, hexafluorophosphate ion, or trifluoromethane sulfonate ion.
- these anions may be used alone or in combination of two or more.
- Preferred are boron tetrafluoride ion, bis (trifluoromethanesulfonyl) imide ion, bis (fluorosulfonyl) imide ion, hexafluorophosphate ion, dicyanamide ion or allyl sulfonate ion, more preferably bis (trifluoromethanesulfonyl) imide ion.
- the ionic liquid examples include 1-allyl-3-ethylimidazolium bromide, 1-ethyl-3-methylimidazolium bromide, 1- (2-hydroxyethyl) -3-methylimidazolium bromide, 1- ( 2-methoxyethyl) -3-methylimidazolium bromide, 1-octyl-3-methylimidazolium chloride, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, 1- Ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide, 1-ethyl-3-methylimidazolium dicyanamide, 1-butyl-1-methyl Pyrrolidinium bis (trifluoromethanesulfonyl) Trimethylbutylammonium bis
- the content of the ionic liquid is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more with respect to 100 parts by mass of the inorganic solid electrolyte.
- 50 mass parts or less are preferable, 20 mass parts or less are more preferable, and 10 mass parts or less are especially preferable.
- the mass ratio of the lithium salt to the ionic liquid is preferably 1:20 to 20: 1, more preferably 1:10 to 10: 1, and particularly preferably 1: 5 to 2: 1.
- the solid electrolyte composition of the present invention may contain a conductive additive.
- a conductive support agent What is known as a general conductive support agent can be used.
- graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black and furnace black, amorphous carbon such as needle coke, vapor-grown carbon fiber and carbon nanotubes, which are electron conductive materials
- Carbon fibers such as graphene, carbonaceous materials such as graphene and fullerene, metal powders such as copper and nickel, and metal fibers may be used, and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives may be used. It may be used.
- 1 type may be used among these and 2 or more types may be used.
- the solid electrolyte composition of the present invention may contain an active material capable of inserting and releasing ions of metal elements belonging to Group 1 or Group 2 of the Periodic Table.
- the active material include a positive electrode active material and a negative electrode active material, and a transition metal oxide that is a positive electrode active material or a metal oxide that is a negative electrode active material is preferable.
- a solid electrolyte composition containing an active material positive electrode active material, negative electrode active material
- an electrode composition positive electrode composition, negative electrode composition
- the positive electrode active material that may be contained in the solid electrolyte composition of the present invention is preferably one that can reversibly insert and release lithium ions.
- the material is not particularly limited as long as it has the above characteristics, and may be a transition metal oxide, an organic substance, an element that can be complexed with Li, such as sulfur, or a complex of sulfur and metal.
- the positive electrode active material it is preferable to use a transition metal oxide, and a transition metal oxide having a transition metal element M a (one or more elements selected from Co, Ni, Fe, Mn, Cu and V). More preferred.
- this transition metal oxide includes an element M b (an element of the first (Ia) group of the metal periodic table other than lithium, an element of the second (IIa) group, Al, Ga, In, Ge, Sn, Pb, Elements such as Sb, Bi, Si, P or B) may be mixed.
- the mixing amount is preferably 0 ⁇ 30 mol% relative to the amount of the transition metal element M a (100mol%). Those synthesized by mixing so that the molar ratio of Li / Ma is 0.3 to 2.2 are more preferable.
- transition metal oxide examples include (MA) a transition metal oxide having a layered rock salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD And lithium-containing transition metal halide phosphate compounds and (ME) lithium-containing transition metal silicate compounds.
- transition metal oxide having a layered rock salt structure LiCoO 2 (lithium cobaltate [LCO]), LiNi 2 O 2 (lithium nickelate) LiNi 0.85 Co 0.10 Al 0.05 O 2 (lithium nickel cobalt aluminate [NCA]), LiNi 1/3 Co 1/3 Mn 1/3 O 2 (nickel manganese lithium cobaltate [NMC]) and LiNi 0.5 Mn 0.5 O 2 (manganese) Lithium nickelate).
- LCO lithium cobaltate
- NCA lithium nickel cobalt aluminate
- NMC nickel manganese lithium cobaltate
- LiNi 0.5 Mn 0.5 O 2 manganese lithium cobaltate
- transition metal oxides having (MB) spinel structure include LiMn 2 O 4 (LMO), LiCoMnO 4, Li 2 FeMn 3 O 8 , Li 2 CuMn 3 O 8 , Li 2 CrMn 3 O 8 and Li 2 NiMn 3 O 8 is mentioned.
- (MC) lithium-containing transition metal phosphate compounds include olivine-type phosphate iron salts such as LiFePO 4 and Li 3 Fe 2 (PO 4 ) 3 , iron pyrophosphates such as LiFeP 2 O 7 , LiCoPO 4, and the like. And monoclinic Nasicon type vanadium phosphate salts such as Li 3 V 2 (PO 4 ) 3 (vanadium lithium phosphate).
- (MD) as the lithium-containing transition metal halogenated phosphate compound for example, Li 2 FePO 4 F such fluorinated phosphorus iron salt, Li 2 MnPO 4 hexafluorophosphate manganese salts such as F and Li 2 CoPO 4 F Cobalt fluorophosphates such as
- Examples of the (ME) lithium-containing transition metal silicate compound include Li 2 FeSiO 4 , Li 2 MnSiO 4, and Li 2 CoSiO 4 .
- a transition metal oxide having a (MA) layered rock salt structure is preferable, and LCO, LMO, NCA or NMC is more preferable.
- the shape of the positive electrode active material is not particularly limited, but is preferably particulate.
- the volume average particle diameter (sphere conversion average particle diameter) of the positive electrode active material is not particularly limited.
- the thickness can be 0.1 to 50 ⁇ m.
- an ordinary pulverizer or classifier may be used.
- the positive electrode active material obtained by the firing method may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.
- the volume average particle diameter (sphere-converted average particle diameter) of the positive electrode active material particles can be measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA).
- the positive electrode active materials may be used alone or in combination of two or more.
- the mass (mg) (weight per unit area) of the positive electrode active material per unit area (cm 2 ) of the positive electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.
- the content of the positive electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 95% by mass, more preferably 30 to 90% by mass, and even more preferably 50 to 85% by mass at 100% by mass. Preferably, it is 55 to 80% by mass.
- the negative electrode active material that may be contained in the solid electrolyte composition of the present invention is preferably one that can reversibly insert and release lithium ions.
- the material is not particularly limited as long as it has the above characteristics, and is a carbonaceous material, a metal oxide such as tin oxide, a silicon oxide, a metal composite oxide, a lithium simple substance and a lithium alloy such as a lithium aluminum alloy, and , Metals such as Sn, Si, Al, and In that can form an alloy with lithium.
- a carbonaceous material or a lithium composite oxide is preferably used from the viewpoint of reliability.
- the metal composite oxide is preferably capable of inserting and extracting lithium.
- the material is not particularly limited, but preferably contains titanium and / or lithium as a constituent component from the viewpoint of high current density charge / discharge characteristics.
- the carbonaceous material used as the negative electrode active material is a material substantially made of carbon.
- various synthetics such as petroleum pitch, carbon black such as acetylene black (AB), graphite (natural graphite, artificial graphite such as vapor-grown graphite), PAN (polyacrylonitrile) -based resin, furfuryl alcohol resin, etc.
- the carbonaceous material which baked resin can be mentioned.
- various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, dehydrated PVA (polyvinyl alcohol) -based carbon fiber, lignin carbon fiber, glassy carbon fiber, and activated carbon fiber. Examples thereof include mesophase microspheres, graphite whiskers, and flat graphite.
- an amorphous oxide is particularly preferable, and chalcogenite, which is a reaction product of a metal element and an element of Group 16 of the periodic table, is also preferably used. It is done.
- amorphous as used herein means an X-ray diffraction method using CuK ⁇ rays, which has a broad scattering band having a peak in the region of 20 ° to 40 ° in terms of 2 ⁇ , and is a crystalline diffraction line. You may have.
- an amorphous oxide of a metalloid element and a chalcogenide are more preferable.
- Ga, Si, Sn, Ge, Pb, Sb and Bi are used alone or in combination of two or more thereof, and chalcogenides are particularly preferable.
- preferable amorphous oxides and chalcogenides include, for example, Ga 2 O 3 , SiO, GeO, SnO, SnO 2 , PbO, PbO 2 , Pb 2 O 3 , Pb 2 O 4 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb 2 O 8 Bi 2 O 3 , Sb 2 O 8 Si 2 O 3 , Bi 2 O 4 , SnSiO 3 , GeS, SnS, SnS 2 , PbS, PbS 2 , Sb 2 S 3 , Sb 2 S 5 and SnSiS 3 are preferred. Moreover, these may be a complex oxide with lithium oxide, for example, Li 2 SnO 2 .
- the negative electrode active material contains a titanium atom. More specifically, Li 4 Ti 5 O 12 (lithium titanate [LTO]) is excellent in rapid charge / discharge characteristics due to small volume fluctuations during the insertion and release of lithium ions, and the deterioration of the electrodes is suppressed, and the lithium ion secondary This is preferable in that the battery life can be improved.
- Li 4 Ti 5 O 12 lithium titanate [LTO]
- a Si-based negative electrode it is also preferable to apply a Si-based negative electrode.
- a Si negative electrode can occlude more Li ions than a carbon negative electrode (such as graphite and acetylene black). That is, the amount of occlusion of Li ions per unit mass increases. Therefore, the battery capacity can be increased. As a result, there is an advantage that the battery driving time can be extended.
- the shape of the negative electrode active material is not particularly limited, but is preferably particulate.
- the average particle size of the negative electrode active material is preferably 0.1 to 60 ⁇ m.
- a normal pulverizer or classifier is used.
- a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill, and a sieve are preferably used.
- pulverizing wet pulverization in the presence of water or an organic solvent such as methanol can be performed as necessary.
- classification is preferably performed.
- the classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be used both dry and wet.
- the average particle diameter of the negative electrode active material particles can be measured by the same method as the above-described method for measuring the volume average particle diameter of the positive electrode active material.
- the chemical formula of the compound obtained by the above firing method can be calculated from an inductively coupled plasma (ICP) emission spectroscopic analysis method as a measurement method, and from a mass difference between powders before and after firing as a simple method.
- ICP inductively coupled plasma
- the said negative electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.
- the mass (mg) (weight per unit area) of the negative electrode active material per unit area (cm 2 ) of the negative electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.
- the content of the negative electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 80% by mass, and more preferably 20 to 80% by mass with a solid content of 100% by mass.
- the surfaces of the positive electrode active material and the negative electrode active material may be coated with another metal oxide.
- the surface coating agent include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li.
- Specific examples include spinel titanate, tantalum oxide, niobium oxide, and lithium niobate compound. Specifically, Li 4 Ti 5 O 12 , Li 2 Ti 2 O 5 , and LiTaO 3.
- the electrode surface containing a positive electrode active material or a negative electrode active material may be surface-treated with sulfur or phosphorus.
- the particle surface of the positive electrode active material or the negative electrode active material may be subjected to a surface treatment with actinic light or an active gas (plasma or the like) before and after the surface coating.
- the solid electrolyte composition of the present invention can be prepared by dispersing the inorganic solid electrolyte (A) and the binder (B) in the presence of the dispersion medium (C) to form a slurry.
- Slurry can be performed by mixing an inorganic solid electrolyte, a binder, and a dispersion medium using various mixers.
- the mixing apparatus is not particularly limited, and examples thereof include a ball mill, a bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader, and a disk mill.
- the mixing conditions are not particularly limited.
- the mixing is preferably performed at 150 to 700 rpm (rotation per minute) for 1 to 24 hours.
- a solid electrolyte composition containing components such as an active material and a particle dispersant, it may be added and mixed simultaneously with the dispersion step of the inorganic solid electrolyte (A) and the binder (B). You may add and mix.
- the solid electrolyte-containing sheet of the present invention contains an inorganic solid electrolyte (A) having a conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table and a binder (B), and a dispersion medium (C). In a total mass of 1 ppm or more and 10,000 ppm or less.
- the dispersion medium (C) contains an alicyclic compound (C1) composed of carbon atoms and hydrogen atoms and / or halogen atoms, and the boiling point of the alicyclic compound (C1) at 760 mmHg is 100 ° C. or higher and 180 ° C. It is below °C.
- the solid electrolyte-containing sheet of the present invention can be suitably used for an all-solid-state secondary battery, and includes various modes depending on the application.
- a sheet preferably used for a solid electrolyte layer also referred to as a solid electrolyte sheet for an all-solid secondary battery
- a sheet preferably used for an electrode or a laminate of an electrode and a solid electrolyte layer an electrode sheet for an all-solid secondary battery Etc.
- these various sheets may be collectively referred to as an all-solid secondary battery sheet.
- the all-solid-state secondary battery sheet is a sheet having a solid electrolyte layer or an active material layer (electrode layer) on a base material.
- the all-solid-state secondary battery sheet may have other layers as long as it has a base material and a solid electrolyte layer or an active material layer. It is classified as a secondary battery electrode sheet. Examples of other layers include a protective layer, a current collector, and a coat layer (current collector, solid electrolyte layer, active material layer) and the like.
- Examples of the solid electrolyte sheet for an all-solid secondary battery include a sheet having a solid electrolyte layer and a protective layer in this order on a base material.
- the substrate is not particularly limited as long as it can support the solid electrolyte layer, and examples thereof include materials described in the current collector, sheet materials (plate bodies) such as organic materials and inorganic materials, and the like.
- the organic material include various polymers, and specific examples include polyethylene terephthalate, polypropylene, polyethylene, and cellulose.
- the inorganic material include glass and ceramic.
- the thickness of the solid electrolyte layer of the all-solid-state secondary battery sheet is the same as the thickness of the solid electrolyte layer described in the above-described all-solid-state secondary battery of the present invention.
- This sheet is obtained by forming (coating and drying) the solid electrolyte composition of the present invention on a base material (which may be via another layer) to form a solid electrolyte layer on the base material. It is done.
- the solid electrolyte composition of the present invention can be prepared by the above-described method.
- the electrode sheet for an all-solid-state secondary battery of the present invention (also simply referred to as “electrode sheet”) is formed on a metal foil as a current collector for forming the active material layer of the all-solid-state secondary battery of the present invention.
- An electrode sheet having an active material layer is usually a sheet having a current collector and an active material layer, but an embodiment having a current collector, an active material layer, and a solid electrolyte layer in this order, and a current collector, an active material layer, and a solid electrolyte The aspect which has a layer and an active material layer in this order is also included.
- the configuration and the layer thickness of each layer constituting the electrode sheet are the same as the configuration and the layer thickness of each layer described in the above-described all solid state secondary battery of the present invention.
- the electrode sheet is obtained by forming (coating and drying) the solid electrolyte composition containing the active material of the present invention on a metal foil to form an active material layer on the metal foil.
- the method for preparing the solid electrolyte composition containing the active material is the same as the method for preparing the solid electrolyte composition except that the active material is used.
- the all solid state secondary battery of the present invention has a positive electrode, a negative electrode facing the positive electrode, and a solid electrolyte layer between the positive electrode and the negative electrode.
- the positive electrode has a positive electrode active material layer on a positive electrode current collector.
- the negative electrode has a negative electrode active material layer on a negative electrode current collector.
- At least one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is preferably formed using the solid electrolyte composition of the present invention.
- the active material layer and / or the solid electrolyte layer formed of the solid electrolyte composition are preferably the same as those in the solid content of the solid electrolyte composition with respect to the component species to be contained and the content ratio thereof.
- a preferred embodiment of the present invention will be described with reference to FIG. 1, but the present invention is not limited to this.
- any of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is formed using the solid electrolyte composition of the present invention. That is, when the solid electrolyte layer 3 is formed of the solid electrolyte composition of the present invention, the solid electrolyte layer 3 includes an inorganic solid electrolyte and a binder. The solid electrolyte layer usually does not contain a positive electrode active material and / or a negative electrode active material.
- the binder exists between solid particles such as the inorganic solid electrolyte and the active material contained in the adjacent active material layer. Therefore, the interfacial resistance between the solid particles is reduced and the binding property is increased.
- the positive electrode active material layer 4 and the negative electrode active material layer 2 are respectively a positive electrode active material or a negative electrode. It contains an active material, and further contains an inorganic solid electrolyte and a binder.
- the active material layer contains an inorganic solid electrolyte, the ionic conductivity can be improved.
- the active material layer it is considered that a binder exists between solid particles. Therefore, the interfacial resistance between the solid particles is reduced and the binding property is increased.
- the inorganic solid electrolyte and the binder contained in the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 may be the same or different from each other.
- the solid electrolyte composition in which any one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer in the all-solid-state secondary battery contains the binder and solid particles such as an inorganic solid electrolyte. It is produced using. For this reason, the binding property between solid particles can be improved, and as a result, good cycle characteristics in an all-solid secondary battery can also be realized.
- the positive electrode current collector 5 and the negative electrode current collector 1 are preferably electronic conductors. In the present invention, either or both of the positive electrode current collector and the negative electrode current collector may be simply referred to as a current collector.
- Materials for forming the positive electrode current collector include aluminum, aluminum alloy, stainless steel, nickel and titanium, as well as the surface of aluminum or stainless steel treated with carbon, nickel, titanium or silver (formation of a thin film) Among them, aluminum and aluminum alloys are more preferable.
- the material for forming the negative electrode current collector is treated with carbon, nickel, titanium or silver on the surface of aluminum, copper, copper alloy or stainless steel. What was made to do is preferable, and aluminum, copper, copper alloy, and stainless steel are more preferable.
- the current collector is usually in the form of a film sheet, but a net, a punched one, a lath, a porous body, a foam, a fiber group molded body, or the like can also be used.
- the thickness of the current collector is not particularly limited, but is preferably 1 to 500 ⁇ m.
- the current collector surface is roughened by surface treatment.
- a functional layer, a member, or the like is appropriately interposed or disposed between or outside each of the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector. May be.
- Each layer may be composed of a single layer or a plurality of layers.
- the basic structure of the all-solid-state secondary battery can be manufactured by arranging each of the above layers. Depending on the application, it may be used as an all-solid secondary battery as it is, but in order to form a dry battery, it is further enclosed in a suitable housing.
- the housing may be metallic or made of resin (plastic). When using a metallic thing, the thing made from an aluminum alloy and stainless steel can be mentioned, for example.
- the metallic housing is preferably divided into a positive-side housing and a negative-side housing, and electrically connected to the positive current collector and the negative current collector, respectively.
- the casing on the positive electrode side and the casing on the negative electrode side are preferably joined and integrated through a gasket for preventing a short circuit.
- the solid electrolyte-containing sheet of the present invention forms a solid electrolyte layer on a substrate by forming (coating and drying) the solid electrolyte composition of the present invention on the substrate (may be through another layer). Is obtained.
- seat for all-solid-state secondary batteries which is a sheet
- the method as described in manufacture of the following all-solid-state secondary battery can be used.
- seat of this invention can be measured with the following method.
- the solid electrolyte-containing sheet is punched out with a 20 mm square and immersed in deuterated tetrahydrofuran in a glass bottle.
- the obtained eluate is filtered through a syringe filter, and quantitative operation is performed by 1 H-NMR.
- the correlation between the 1 H-NMR peak area and the amount of solvent is determined by preparing a calibration curve.
- Manufacture of all-solid-state secondary battery and electrode sheet for all-solid-state secondary battery can be performed by a conventional method. Specifically, the all-solid-state secondary battery and the all-solid-state secondary battery electrode sheet can be manufactured by forming each of the above layers using the solid electrolyte composition of the present invention. This will be described in detail below.
- the all-solid-state secondary battery of the present invention is produced by a method including (intervening) the step of applying the solid electrolyte composition of the present invention onto a metal foil to be a current collector and forming (forming) a coating film.
- a solid electrolyte composition containing a positive electrode active material is applied as a positive electrode material (positive electrode composition) on a metal foil as a positive electrode current collector to form a positive electrode active material layer, and an all-solid secondary A positive electrode sheet for a battery is prepared.
- a solid electrolyte composition for forming a solid electrolyte layer is applied on the positive electrode active material layer to form a solid electrolyte layer.
- a solid electrolyte composition containing a negative electrode active material is applied as a negative electrode material (negative electrode composition) on the solid electrolyte layer to form a negative electrode active material layer.
- An all-solid secondary battery having a structure in which a solid electrolyte layer is sandwiched between a positive electrode active material layer and a negative electrode active material layer is obtained by stacking a negative electrode current collector (metal foil) on the negative electrode active material layer. Can do. If necessary, this can be enclosed in a housing to obtain a desired all-solid secondary battery.
- each layer is reversed, and a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer are formed on the negative electrode current collector, and the positive electrode current collector is stacked to manufacture an all-solid secondary battery.
- Another method includes the following method. That is, a positive electrode sheet for an all-solid secondary battery is produced as described above. Further, a negative electrode active material layer is formed by applying a solid electrolyte composition containing a negative electrode active material as a negative electrode material (negative electrode composition) on a metal foil as a negative electrode current collector, and forming an all-solid secondary A negative electrode sheet for a battery is prepared. Next, a solid electrolyte layer is formed on one of the active material layers of these sheets as described above. Furthermore, the other of the positive electrode sheet for an all solid secondary battery and the negative electrode sheet for an all solid secondary battery is laminated on the solid electrolyte layer so that the solid electrolyte layer and the active material layer are in contact with each other.
- Another method includes the following method. That is, as described above, a positive electrode sheet for an all-solid secondary battery and a negative electrode sheet for an all-solid secondary battery are produced. Separately from this, a solid electrolyte composition is applied on a substrate to produce a solid electrolyte sheet for an all-solid secondary battery comprising a solid electrolyte layer. Furthermore, it laminates
- An all-solid-state secondary battery can also be manufactured by a combination of the above forming methods. For example, as described above, a positive electrode sheet for an all-solid secondary battery, a negative electrode sheet for an all-solid secondary battery, and a solid electrolyte sheet for an all-solid secondary battery are produced. Subsequently, after laminating the solid electrolyte layer peeled off from the base material on the negative electrode sheet for an all solid secondary battery, an all solid secondary battery can be manufactured by pasting the positive electrode sheet for the all solid secondary battery. it can. In this method, the solid electrolyte layer can be laminated on the positive electrode sheet for an all-solid secondary battery, and bonded to the negative electrode sheet for an all-solid secondary battery.
- the method for applying the solid electrolyte composition is not particularly limited, and can be appropriately selected. Examples thereof include coating (preferably wet coating), spray coating, spin coating coating, dip coating, slit coating, stripe coating, and bar coating coating. At this time, the solid electrolyte composition may be dried after being applied, or may be dried after being applied in multiple layers.
- the drying temperature is not particularly limited.
- the lower limit is preferably 30 ° C or higher, more preferably 60 ° C or higher, and still more preferably 80 ° C or higher.
- the upper limit is preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and further preferably 200 ° C. or lower.
- a dispersion medium By heating in such a temperature range, a dispersion medium can be removed and it can be set as a solid state. Moreover, it is preferable because the temperature is not excessively raised and each member of the all-solid-state secondary battery is not damaged. Thereby, in the all-solid-state secondary battery, excellent overall performance can be exhibited and good binding properties can be obtained.
- each layer or all-solid secondary battery After producing the applied solid electrolyte composition or all-solid-state secondary battery. Moreover, it is also preferable to pressurize in the state which laminated
- An example of the pressurizing method is a hydraulic cylinder press.
- the applied pressure is not particularly limited and is generally preferably in the range of 50 to 1500 MPa. Moreover, you may heat the apply
- the heating temperature is not particularly limited, and is generally in the range of 30 to 300 ° C. It is also possible to press at a temperature higher than the glass transition temperature of the inorganic solid electrolyte.
- the pressurization may be performed in a state where the coating solvent or the dispersion medium is previously dried, or may be performed in a state where the solvent or the dispersion medium remains.
- each composition may be apply
- the atmosphere during pressurization is not particularly limited, and may be any of the following: air, dry air (dew point -20 ° C. or lower), and inert gas (for example, argon gas, helium gas, nitrogen gas).
- the pressing time may be a high pressure in a short time (for example, within several hours), or a medium pressure may be applied for a long time (1 day or more).
- a restraining tool screw tightening pressure or the like
- the pressing pressure may be uniform or different with respect to the pressed part such as the sheet surface.
- the pressing pressure can be changed according to the area and film thickness of the pressed part. Also, the same part can be changed stepwise with different pressures.
- the press surface may be smooth or roughened.
- the all solid state secondary battery manufactured as described above is preferably initialized after manufacture or before use.
- the initialization is not particularly limited, and can be performed, for example, by performing initial charging / discharging in a state where the press pressure is increased, and then releasing the pressure until the general use pressure of the all-solid secondary battery is reached.
- the all solid state secondary battery of the present invention can be applied to various uses. Although there is no particular limitation on the application mode, for example, when installed in an electronic device, a notebook computer, a pen input personal computer, a mobile personal computer, an electronic book player, a mobile phone, a cordless phone, a pager, a handy terminal, a mobile fax machine, a mobile phone Copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, electric shaver, transceiver, electronic notebook, calculator, portable tape recorder, radio, backup power supply, memory card, etc.
- Others for consumer use include automobiles (electric cars, etc.), electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder massagers, etc.) . Furthermore, it can be used for various military use and space use. Moreover, it can also combine with a solar cell.
- An all-solid secondary battery in which at least one of a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer contains a lithium salt.
- a method for producing an all-solid-state secondary battery wherein the solid electrolyte layer is wet-coated with a slurry in which a lithium salt and a sulfide-based inorganic solid electrolyte are dispersed by a dispersion medium.
- a solid electrolyte composition containing an active material for producing the all-solid secondary battery [4] A battery electrode sheet obtained by applying the solid electrolyte composition on a metal foil to form a film.
- the preferred methods for producing the all-solid-state secondary battery and the battery electrode sheet of the present invention are both wet processes. Thereby, even in a region where the content of the inorganic solid electrolyte in at least one of the positive electrode active material layer and the negative electrode active material layer is as low as 10% by mass or less, the adhesiveness between the active material and the inorganic solid electrolyte is increased, and an efficient ion conduction path. Can be maintained, and an all-solid-state secondary battery having a high energy density (Wh / kg) and high power density (W / kg) per battery mass can be manufactured.
- An all-solid secondary battery refers to a secondary battery in which the positive electrode, the negative electrode, and the electrolyte are all solid. In other words, it is distinguished from an electrolyte type secondary battery using a carbonate-based solvent as an electrolyte.
- this invention presupposes an inorganic all-solid-state secondary battery.
- the all-solid-state secondary battery includes an organic (polymer) all-solid-state secondary battery that uses a polymer compound such as polyethylene oxide as an electrolyte, and an inorganic all-solid-state that uses the above-described Li—PS glass, LLT, LLZ, or the like. It is divided into secondary batteries.
- an organic compound to an inorganic all-solid secondary battery is not hindered, and the organic compound can be applied as a binder or additive for a positive electrode active material, a negative electrode active material, and an inorganic solid electrolyte.
- the inorganic solid electrolyte is distinguished from an electrolyte (polymer electrolyte) using the above-described polymer compound as an ion conductive medium, and the inorganic compound serves as an ion conductive medium. Specific examples include the above-described Li—PS glass, LLT, and LLZ.
- the inorganic solid electrolyte itself does not release cations (Li ions) but exhibits an ion transport function.
- electrolyte a material that is added to the electrolytic solution or the solid electrolyte layer and serves as a source of ions that release cations (Li ions) is sometimes called an electrolyte.
- electrolyte salt When distinguishing from the electrolyte as the above ion transport material, this is called “electrolyte salt” or “supporting electrolyte”.
- electrolyte salt An example of the electrolyte salt is LiTFSI.
- composition means a mixture in which two or more components are uniformly mixed. However, as long as the uniformity is substantially maintained, aggregation or uneven distribution may partially occur within a range in which a desired effect is achieved.
- Li 2 S lithium sulfide
- P 2 S 5 diphosphorus pentasulfide
- ⁇ Measurement method of volume average particle diameter> (Measurement of volume average particle diameter of inorganic solid electrolyte before addition to solid electrolyte composition)
- a dynamic light scattering particle size distribution analyzer (trade name: LB-500, manufactured by Horiba, Ltd.) according to JIS 8826: 2005, the synthesized sulfide-based inorganic solid electrolyte particles are separated into 20 ml sample bottles. The sample is taken and diluted with toluene so that the solid content concentration becomes 0.2% by mass. Data is taken 50 times at a temperature of 25 ° C. using a 2 ml measuring quartz cell, and the obtained volume-based arithmetic is performed. The average was taken as the average particle size. The 50% cumulative particle size from the fine particle side of the cumulative particle size distribution was defined as the cumulative 50% particle size. The average particle size of the particles before mixing was measured by this method.
- Example 1 The solid electrolyte composition prepared later was subjected to a dispersion stability test, measurement of viscosity, measurement of the volume average particle diameter of the inorganic solid electrolyte in the solid electrolyte composition, and measurement of ionic conductivity. The test and measurement results are summarized in Table 1 below. In addition, a dispersion stability test and a viscosity measurement were performed on the positive electrode composition and the negative electrode composition prepared below. The test and measurement results are summarized in Tables 2 and 3 below. The test method and measurement method are described below.
- ⁇ Dispersion stability test> Each of the following compositions was prepared and allowed to stand at 25 ° C. for 24 hours in a transparent sample bottle. The state of each composition before and after standing for 24 hours was visually observed. The solid components of each composition before standing for 24 hours and the solid components of each composition after standing for 24 hours were visually observed and evaluated according to the following evaluation criteria. The evaluation criteria are shown below. Ranks A to C are acceptable levels. ⁇ Evaluation criteria> A: No change (sedimentation) was observed. B: The ratio of the precipitated solid component is 10% or less C: The ratio of the precipitated solid component is more than 10% and 30% or less D: The ratio of the precipitated solid component is more than 30% and 80% or less E: The precipitated solid component Of over 80%
- ⁇ Measurement method of volume average particle diameter> (Measurement of volume average particle diameter of inorganic solid electrolyte in solid electrolyte composition)
- a dynamic light scattering particle size distribution analyzer (trade name: LB-500, manufactured by Horiba, Ltd.) in accordance with JIS 8826: 2005
- the solid electrolyte composition is dispensed into 20 ml sample bottles and solidified with toluene.
- the dilution was adjusted so that the partial concentration became 0.2% by mass, and data acquisition was performed 50 times at a temperature of 25 ° C. using a 2 ml quartz cell for measurement. did.
- the 50% cumulative particle size from the fine particle side of the cumulative particle size distribution was defined as the cumulative 50% particle size.
- the average particle size of the inorganic solid electrolyte particles in the solid electrolyte composition was measured by this method. The results are summarized in Table 1 below.
- ⁇ Ion conductivity measurement> The slurry of the solid electrolyte composition was dried at atmospheric pressure for 2 hours on a hot plate heated to 100 ° C. in a dry air having a dew point of ⁇ 60 ° C.
- the ionic conductivity of the obtained dry powder was measured by the impedance method. 300 mg of the dry powder was packed in a cylinder having a diameter of 14.5 mm to produce a coin-type jig. It was sandwiched between jigs capable of applying a pressure of 500 kgf / cm 2 between the electrodes from the outside of the coin-shaped jig, and used for measurement of ion conductivity.
- the ion conductivity at a pressure 500 kgf / cm 2
- the specimen shown in FIG. 2 was used for pressurization of the coin-type jig. 11 is an upper support plate, 12 is a lower support plate, 13 is a coin-type jig, and S is a screw.
- Table 1 summarizes the composition and components of the solid electrolyte composition.
- the solid electrolyte compositions S-1 to S-19 are solid electrolyte compositions of the present invention
- the solid electrolyte compositions T-1 to T-4 are comparative solid electrolyte compositions.
- B-1 PVdF-HFP (manufactured by Arkema)
- B-2 SBR (manufactured by JSR)
- B-3 Acrylic acid-methyl acrylate copolymer prepared by the following method (20/80 molar ratio Mw25000)
- 1.2 g of acrylic acid manufactured by Wako Pure Chemical Industries, Ltd.
- 4.2 g of methyl acrylate manufactured by Wako Pure Chemical Industries, Ltd.
- MEK methyl ethyl ketone
- B-4 Acrylic latex Binder (B-1) described in JP-A-2015-88486, average particle size: 450 ⁇ m (dispersion medium: ethylcyclohexane), average particle diameter: 180 ⁇ m (dispersion medium: chlorocyclohexane)
- B-5 Urethane polymer Exemplified compound (44) described in JP-A-2015-88480 (The average particle size of the binder is only described in the form of particles in the dispersion medium.)
- LLZ Li 7 La 3 Zr 2 O 12 (manufactured by Toshima Seisakusho)
- Li / P / S The boiling point (° C.) of the Li—PS system glass alicyclic compound (C1) synthesized above is the boiling point at 760 mmHg, and the viscosity (mPa ⁇ s) of the alicyclic compound (C1) is The viscosity at 20 ° C is shown.
- LiTFSI lithium bis (trifluoromethanesulfonyl) imide
- TMBATFSI trimethylbutylammonium bis (trifluoromethanesulfonyl) imide
- EMImTFSI 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide particle diameter: volume average particle of inorganic solid electrolyte Means diameter.
- the average particle diameter of the binder particles was measured according to the following procedure. A 1% by mass dispersion was prepared using the above binder with an arbitrary solvent (dispersion medium used for preparing the solid electrolyte composition. In the case of binder B-1, ethylcyclohexane or chlorocyclohexane). Using this dispersion sample, the volume average particle diameter of the binder particles was measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by HORIBA).
- Table 2 below summarizes the composition of the positive electrode solid electrolyte composition.
- positive electrode solid electrolyte compositions P-1 to P-19 are solid electrolyte compositions of the present invention
- positive electrode solid electrolyte compositions HP-1 to HP-4 are comparative solid electrolyte compositions.
- LCO LiCoO 2
- LMO LiMn 2 O 4 NCA: LiNi 0.85 Co 0.10 Al 0.05
- NMC LiNi 1/3 Co 1/3 Mn 1/3 O 2 AB: Acetylene black
- composition for negative electrode- 50 zirconia beads having a diameter of 3 mm were put into a 45 mL container (manufactured by Fritsch) made of zirconia, and 6.8 g of the inorganic solid electrolyte composition (S-1) synthesized above was added.
- a container manufactured by Fritsch
- LTO Li 4 Ti 5 O 12
- this container was set in a planetary ball mill P-7 (manufactured by Fritsch), and the temperature was 25 ° C. and the rotational speed was 100 rpm for 10 minutes. Stirring was continued to prepare a solid electrolyte composition N-1 for negative electrode.
- Table 3 summarizes the composition of the negative electrode solid electrolyte composition.
- the negative electrode solid electrolyte compositions N-1 to N-17 are solid electrolyte compositions of the present invention
- the negative electrode solid electrolyte compositions HN-1 to HN-4 are comparative solid electrolyte compositions.
- the solid electrolyte composition of the present invention is excellent in dispersion stability of the solid electrolyte, has a viscosity suitable for battery production, and can be dispersed in a dispersion medium in a more refined state of the inorganic solid electrolyte. . It turns out that the ionic conductivity of the obtained powder is maintained with high.
- Electrode sheet PS-1 ⁇ Preparation of electrode sheet ⁇
- the slurry of the positive electrode solid electrolyte composition P-1 was applied onto an aluminum foil having a thickness of 40 ⁇ m with an applicator (trade name: SA-201 Baker type applicator, manufactured by Tester Sangyo Co., Ltd.), and 120 ° C. using a heat press machine.
- the dispersion medium was removed by heating for 1 hour to obtain an electrode sheet PS-1 for an all-solid-state secondary battery having a thickness of about 160 ⁇ m (electrode sheet PS-1 for positive electrode).
- positive electrode sheets PS-2 to PS-19 and HPS-1 to HPS-4 were produced.
- the positive electrode layers PS-1 to PS-19 and HPS-1 to HPS-4 indicate that the positive electrode layer of the all-solid-state secondary battery is the positive electrode sheet PS-1 to PS-19 and HPS-1, respectively. Means a positive electrode layer of HPS-4.
- a solid electrolyte sheet S-1 for an all-solid-state secondary battery was produced using the solid electrolyte composition S-1 in the same manner as the positive electrode sheet PS-1.
- Solid electrolyte sheets S-2 to S-19 and HS-1 to HS-4 for all solid secondary batteries were produced in the same manner as the solid electrolyte sheet S-1 for all solid secondary batteries.
- solid electrolyte layers S-1 to S-19 and HS-1 to HS-4 are solid electrolyte layers for all solid secondary batteries, respectively. It means a solid electrolyte layer of S-19 and HS-1 to HS-4.
- a negative electrode sheet NS-1 was produced using the negative electrode solid electrolyte composition N-1.
- negative electrode sheets NS-2 to NS-17 and HNS-1 to HNS-4 were produced.
- the negative electrode layers NS-1 to NS-17 and HNS-1 to HNS-4 are the negative electrode layers of the all-solid-state secondary battery, respectively, and the negative electrode sheets NS-1 to NS-17 and HNS-1 Means a negative electrode layer of HNS-4.
- the solid electrolyte composition S-1 was applied onto a Teflon (registered trademark) sheet with an applicator (trade name: SA-201 Baker type applicator, manufactured by Tester Sangyo Co., Ltd.) and dried at 120 ° C. for 0.1 hour. This was bonded to the positive electrode sheet PS-1 obtained above to remove the Teflon sheet.
- the negative electrode sheet NS-1 obtained above was bonded to the solid electrolyte layer side and pressed at 300 MPa for 5 seconds using a press. As shown in FIG.
- the electrode sheet 16 for the all-solid-state secondary battery manufactured as described above is cut into a disk shape having a diameter of 14.5 mm, and 2032 made of stainless steel incorporating a spacer and a washer (both not shown in FIG. 3).
- the battery voltage of the all-solid secondary battery produced above was measured with a charge / discharge evaluation apparatus “TOSCAT-3000 (trade name)” manufactured by Toyo System. Charging was performed until the battery voltage reached 4.2 V at a current density of 2 A / m 2. After reaching 4.2 V, constant voltage charging was performed until the current density was less than 0.2 A / m 2 . Discharging was performed at a current density of 2 A / m 2 until the battery voltage reached 3.0V. This was repeated three times as one cycle, and the battery voltage after 5 mAh / g discharge in the third cycle was read and evaluated according to the following criteria. Ranks A to C are acceptable levels.
- the content ratio of the dispersion medium (C) in the sheets constituting each layer was 1 ppm or more and 10000 ppm or less in the total mass in any sheet.
- the measurement of the content rate was performed by the above-mentioned method.
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Abstract
Description
かかる状況下、有機電解液に代えて、無機固体電解質を用いた全固体二次電池が注目されている。全固体二次電池は負極、電解質および正極のすべてが固体からなり、有機電解液を用いた電池の課題とされる安全性ないし信頼性を大きく改善することができ、また長寿命化も可能になるとされる。さらに、全固体二次電池は、電極と電解質を直接並べて直列に配した構造とすることができる。そのため、有機電解液を用いた二次電池に比べて高エネルギー密度化が可能となり、電気自動車や大型蓄電池等への応用が期待されている。
(1)周期律表第1族又は第2族に属する金属のイオンの伝導性を有する無機固体電解質(A)と、バインダー(B)と、分散媒体(C)とを含有する固体電解質組成物であって、
分散媒体(C)が、炭素原子と、水素原子および/またはハロゲン原子とで構成された脂環式化合物(C1)を含み、760mmHgにおける脂環式化合物(C1)の沸点が100℃以上180℃以下である固体電解質組成物。
(2)脂環式化合物(C1)が、環内に不飽和結合を含まず、かつ、単環状である(1)に記載の固体電解質組成物。
(3)脂環式化合物(C1)が、炭素数2以上のアルキル基、アルケニル基、アルキニル基およびハロゲン原子からなる群から選択される少なくとも1種を有する(1)または(2)に記載の固体電解質組成物。
(4)脂環式化合物(C1)が、6~8員環の化合物である(1)~(3)のいずれか1つに記載の固体電解質組成物。
(5)分散媒体(C)中の、脂環式化合物(C1)の割合が20質量%~100質量%である(1)~(4)のいずれか1つに記載の固体電解質組成物。
(6)無機固体電解質(A)が、硫化物系無機固体電解質である(1)~(5)のいずれか1つに記載の固体電解質組成物。
(7)バインダー(B)が、アクリル樹脂、ポリウレタン樹脂、ポリウレア樹脂、ポリイミド樹脂、含フッ素樹脂および炭化水素系熱可塑性樹脂からなる群から選択される少なくとも1種である(1)~(6)のいずれか1つに記載の固体電解質組成物。
(8)バインダー(B)が極性基を有する(1)~(7)のいずれか1つに記載の固体電解質組成物。
(9)バインダー(B)が分散媒体(C)に対して不溶の粒子である(1)~(8)のいずれか1つに記載の固体電解質組成物。
(10)バインダー(B)が、平均粒子径10~1000nmのナノ粒子である(9)に記載の固体電解質組成物。
(11)活物質(D)を含有する(1)~(10)のいずれか1つに記載の固体電解質組成物。
(12)導電助剤を含有する(1)~(11)のいずれか1つに記載の固体電解質組成物。
(13)リチウム塩を含有する(1)~(12)のいずれか1つに記載の固体電解質組成物。
(14)イオン液体を含有する(1)~(13)のいずれか1つに記載の固体電解質組成物。
(15)周期律表第1族又は第2族に属する金属のイオンの伝導性を有する無機固体電解質(A)とバインダー(B)とを含有し、分散媒体(C)を全質量中1ppm以上10000ppm以下含有する固体電解質含有シートであって、分散媒体(C)が、炭素原子と、水素原子および/またはハロゲン原子とで構成された脂環式化合物(C1)を含み、760mmHgにおける脂環式化合物(C1)の沸点が100℃以上180℃以下である固体電解質含有シート。
(16) (1)~(14)のいずれか1つに記載の固体電解質組成物を基材上に塗布し、塗膜を形成する工程を含む固体電解質含有シートの製造方法。
(17)正極活物質層、負極活物質層および固体電解質層を具備する全固体二次電池であって、
正極活物質層、負極活物質層および固体電解質層の少なくとも1つの層が(15)に記載の固体電解質含有シートである全固体二次電池。
(18) (16)に記載の製造方法を介して、全固体二次電池を製造する全固体二次電池の製造方法。
本明細書において、単に「アクリル」又は「(メタ)アクリル」と記載するときは、メタアクリル及び/又はアクリルを意味する。また、単に「アクリロイル」又は「(メタ)アクリロイル」と記載するときは、メタアクリロイル及び/又はアクリロイルを意味する。
本明細書において、特定の符号で表示された置換基および連結基等(以下、置換基等という)が複数あるとき、あるいは複数の置換基等を同時もしくは択一的に規定するときには、それぞれの置換基等は互いに同一でも異なっていてもよいことを意味する。このことは、置換基等の数の規定についても同様である。
また、本発明の製造方法によれば、上記の優れた特性ないしは性能を持つ、固体電解質含有シート及び全固体二次電池それぞれを好適に製造することができる。
本発明の上記及び他の特徴及び利点は、適宜添付の図面を参照して、下記の記載からより明らかになるであろう。
図1は、本発明の好ましい実施形態に係る全固体二次電池(リチウムイオン二次電池)を模式化して示す断面図である。本実施形態の全固体二次電池10は、負極側からみて、負極集電体1、負極活物質層2、固体電解質層3、正極活物質層4、正極集電体5を、この順に有する。各層はそれぞれ接触しており、積層した構造をとっている。このような構造を採用することで、充電時には、負極側に電子(e-)が供給され、そこにリチウムイオン(Li+)が蓄積される。一方、放電時には、負極に蓄積されたリチウムイオン(Li+)が正極側に戻され、作動部位6に電子が供給される。図示した例では、作動部位6に電球を採用しており、放電によりこれが点灯するようにされている。本発明の固体電解質組成物は、上記負極活物質層、正極活物質層、固体電解質層の成形材料として好ましく用いることができる。また、本発明の固体電解質含有シートは、上記負極活物質層、正極活物質層、固体電解質層として好適である。
本明細書において、正極活物質層(以下、正極層とも称す。)と負極活物質層(以下、負極層とも称す。)をあわせて電極層または活物質層と称することがある。
なお、図1に示す層構成を有する全固体二次電池を2032型コインケースに入れる場合、図1に示す層構成を有する全固体二次電池を全固体二次電池用電極シートと称し、この全固体二次電池用電極シートを2032型コインケースに入れて作製した電池を全固体二次電池と称して呼び分けることもある。
本発明の固体電解質組成物は、周期律表第1族又は第2族に属する金属のイオンの伝導性を有する無機固体電解質(A)と、バインダー(B)と、分散媒体(C)とを含有する。上記分散媒体(C)は、脂環式化合物(C1)を含み、760mmHgにおける脂環式化合物(C1)の沸点は、100℃以上180℃以下である。
以下、無機固体電解質(A)、バインダー(B)および分散媒体(C)を、それぞれ無機固体電解質、バインダーおよび分散媒体と記載することもある。
無機固体電解質とは、無機の固体電解質のことであり、固体電解質とは、その内部においてイオンを移動させることができる固体状の電解質のことである。主たるイオン伝導性材料として有機物を含むものではないことから、有機固体電解質(ポリエチレンオキシド(PEO)などに代表される高分子電解質、リチウムビス(トリフルオロメタンスルホニル)イミド(LiTFSI)などに代表される有機電解質塩)とは明確に区別される。また、無機固体電解質は定常状態では固体であるため、通常カチオンおよびアニオンに解離または遊離していない。この点で、電解液やポリマー中でカチオンおよびアニオンが解離または遊離している無機電解質塩(LiPF6、LiBF4,LiFSI,LiClなど)とも明確に区別される。無機固体電解質は周期律表第1族または第2族に属する金属のイオンの伝導性を有するものであれば特に限定されず電子伝導性を有さないものが一般的である。
硫化物系無機固体電解質は、硫黄原子(S)を含有し、かつ、周期律表第1族または第2族に属する金属のイオン伝導性を有し、かつ、電子絶縁性を有するものが好ましい。硫化物系無機固体電解質は、元素として少なくともLi、SおよびPを含有し、リチウムイオン伝導性を有しているものが好ましいが、目的または場合に応じて、Li、SおよびP以外の他の元素を含んでもよい。
例えば下記式(1)で示される組成を満たすリチウムイオン伝導性無機固体電解質が挙げられる。
La1Mb1Pc1Sd1Ae1 式(1)
式中、LはLi、NaおよびKから選択される元素を示し、Liが好ましい。Mは、B、Zn、Sn、Si、Cu、Ga、Sb、Al及びGeから選択される元素を示す。Aは、I、Br、Cl及びFから選択される元素を示す。a1~e1は各元素の組成比を示し、a1:b1:c1:d1:e1は1~12:0~5:1:2~12:0~10を満たす。a1はさらに、1~9が好ましく、1.5~7.5がより好ましい。b1は0~3が好ましい。d1はさらに、2.5~10が好ましく、3.0~8.5がより好ましい。e1はさらに、0~5が好ましく、0~3がより好ましい。
硫化物系無機固体電解質は、例えば硫化リチウム(Li2S)、硫化リン(例えば五硫化二燐(P2S5))、単体燐、単体硫黄、硫化ナトリウム、硫化水素、ハロゲン化リチウム(例えばLiI、LiBr、LiCl)及び上記Mであらわされる元素の硫化物(例えばSiS2、SnS、GeS2)の中の少なくとも2つ以上の原料の反応により製造することができる。
酸化物系無機固体電解質は、酸素原子(O)を含有し、かつ、周期律表第1族または第2族に属する金属のイオン伝導性を有し、かつ、電子絶縁性を有する化合物が好ましい。
なお、固体電解質組成物に含有させる前の無機固体電解質の体積平均粒子径は、後述の実施例の項に記載の方法により算出することができる。
固体電解質組成物中の無機固体電解質の体積平均粒子径は特に限定されないが、小さい程好ましい。全固体二次電池において、無機固体電解質の体積平均粒子径が小さい程、無機固体電解質と活物質との表面接触面積が大きくなる。その結果、リチウムイオンが、全固体二次電池を構成する各層中および各層間を移動しやすくなるからである。無機固体電解質の体積平均粒子径の下限は、0.1μm以上であることが実際的である。一方、無機固体電解質と活物質との表面接触面積を考慮すると、無機固体電解質の体積平均粒子径の上限は、10μm以下が好ましく、5μm以下がより好ましく、2μm以下が特に好ましい。
なお、固体電解質組成物中の無機固体電解質の体積平均粒子径は、後述の実施例の項に記載の方法により算出することができる。
上記無機固体電解質は、1種を単独で用いても、2種以上を組み合わせて用いてもよい。
なお、本明細書において固形分とは、窒素雰囲気下170℃で6時間乾燥処理を行ったときに、揮発ないし蒸発して消失しない成分をいう。典型的には、後述の分散媒体以外の成分を指す。
本発明の固体電解質組成物はバインダー(B)を含有する。
本発明で使用するバインダーは、有機ポリマーであれば特に限定されない。
本発明に用いることができるバインダーは、特に制限はなく、例えば、以下に述べる樹脂からなるバインダーが好ましい。
炭化水素系熱可塑性樹脂としては、例えば、ポリエチレン、ポリプロピレン、スチレンブタジエンゴム(SBR)、水素添加スチレンブタジエンゴム(HSBR)、ブチレンゴム、アクリロニトリルブタジエンゴム、ポリブタジエン、ポリイソプレンが挙げられる。
アクリル樹脂としては、各種の(メタ)アクリルモノマー類、(メタ)アクリルアミドモノマー類、およびこれら樹脂を構成するモノマーの共重合体(好ましくは、アクリル酸とアクリル酸メチルとの共重合体)が挙げられる。
また、そのほかのビニル系モノマーとの共重合体(コポリマー)も好適に用いられる。例えば、(メタ)アクリル酸メチルとスチレンとの共重合体、(メタ)アクリル酸メチルとアクリロニトリルとの共重合体、(メタ)アクリル酸ブチルとアクリロニトリルとスチレンとの共重合体が挙げられる。本願明細書において、コポリマーは、統計コポリマー、周期コポリマー、ブロックコポリマーおよびグラフトコポリマーのいずれでもよく、ブロックコポリマーが好ましい。
その他の樹脂としては例えばポリウレタン樹脂、ポリウレア樹脂、ポリアミド樹脂、ポリイミド樹脂、ポリエステル樹脂、ポリエーテル樹脂、ポリカーボネート樹脂、セルロース誘導体樹脂等が挙げられる。
これらは1種を単独で用いても、2種以上を組み合わせて用いてもよい。
本発明において、バインダーが分散媒体に対して不溶の粒子であることが固体電解質組成物の分散安定性の観点から好ましい。ここで、「バインダーが分散媒体に対して不溶の粒子である」とは、30℃の分散媒体に添加し、24時間静置しても、平均粒子径が5%以上低下しないことを意味し、3%以上低下しないことが好ましく、1%以上低下しないことがより好ましい。
なお、バインダー粒子が分散媒体に全く溶解していない状態では、添加前に対する平均粒子径の上記変化量は0%である。
また、固体電解質組成物中におけるバインダーは、無機固体電解質の粒子間イオン伝導性の低下抑制のため、平均粒子径10~1000nmのナノ粒子であることが好ましい。
バインダーの平均粒子径は、後述の実施例の項に記載の方法により算出することができる。
また、本発明に用いられるバインダーを構成するポリマーは、固体の状態で使用しても良いし、ポリマー粒子分散液またはポリマー溶液の状態で用いてもよい。
本発明では、バインダーの質量に対する、無機固体電解質と活物質の合計質量(総量)の質量比[(無機固体電解質の質量+活物質の質量)/バインダーの質量]は、1,000~1の範囲が好ましい。この比率はさらに500~2がより好ましく、100~10がさらに好ましい。
本発明の分散媒体は、脂環式化合物(C1)を含む。脂環式化合物(C1)は、常圧(760mmHg)における沸点が100℃以上180℃以下であり、後述のように特定の原子で構成される化合物であれば特に制限されない。
理由は定かではないが、本発明では、分散媒体が脂環式化合物(C1)を含むことにより、スラリーである固体電解質組成物が、分散安定性に優れるだけでなく、電池の製造に適した粘度を有する。本発明の固体電解質組成物により、正極活物質層、固体電解質層および負極活物質層を層厚が均一になるように形成することがき、かつ、低温での乾燥により分散媒体を所定の量除くことができる。各層においても、固体電解質組成物中と同様に均一に固形成分が分散されていると考えられ、全固体二次電池の電圧向上に寄与すると考えられる。
また、本発明において、脂環式化合物を用いることにより、固体電解質組成物中に微細化された無機固体電解質を分散させることができ、かつ、固体電解質含有シートはイオン伝導性に優れる。この理由は定かではないが、以下のように推定される。すなわち、分散媒体が脂環式化合物を含むことにより、固体電解質組成物を調製する際、無機固体電解質を微細化するためのエネルギー(例えば、ボールミルを用いる場合、ボールの回転エネルギー)が十分に無機固体電解質に伝わるため、無機固体電解質を十分に微細化することができると考えられる。さらに、無機固体電解質は、脂環式化合物に対して安定であるため、無機固体電解質の溶解や分解が抑制され、イオン伝導度の低下を最小限にとどめることができると考えられる。
後述の置換基Pとして挙げられるアルケニル基の中でも、炭素数2~6のアルキル基が好ましく、より好ましくは炭素数2~4である。
後述の置換基Pとして挙げられるアルキニル基の中でも、炭素数2~6のアルキル基が好ましく、より好ましくは炭素数2~4である。
後述の置換基Pとして挙げられるハロゲン原子の中でも、塩素原子がより好ましい。
無置換の化合物としては、シクロヘプタン(bp118℃、「bp」は沸点「boiling point」を省略した表記、以下同様。)、シクロオクタン(bp149℃)、シクロノナン(bp178℃)等が挙げられる。
脂環式化合物(C1)は、1種単独で用いてもよく、2種以上を混合して用いても良い。
粘度が上記範囲内にあることで、スラリーである固体電解質組成物が、より分散安定性に優れ、固体電解質組成物を基材に塗布して得られる層の、層厚均一性にもより優れるためである。
なお、本発明の固体電解質組成物の20℃における粘度は、下限が30mPa・s以上が好ましく、50mPa・s以上がより好ましく、100mPa・s以上が特に好ましい。上限は特に限定されないが、10000mPa・s以下が好ましく、1000mPa・s以下がより好ましく、500mPa・s以下が特に好ましい。
含有量が上記範囲内にあることで、スラリーである固体電解質組成物が、より分散安定性に優れ、固体電解質組成物を基材に塗布して得られる層の、層厚均一性にもより優れるためである。
置換基Pとしては、下記のものが挙げられる。
アルキル基(好ましくは炭素原子数1~20のアルキル基、例えばメチル、エチル、イソプロピル、t-ブチル、ペンチル、ヘプチル、1-エチルペンチル、ベンジル、2-エトキシエチル、1-カルボキシメチル等)、アルケニル基(好ましくは炭素原子数2~20のアルケニル基、例えば、ビニル、アリル、オレイル等)、アルキニル基(好ましくは炭素原子数2~20のアルキニル基、例えば、エチニル、ブタジイニル、フェニルエチニル等)、シクロアルキル基(好ましくは炭素原子数3~20のシクロアルキル基、例えば、シクロプロピル、シクロペンチル、シクロヘキシル、4-メチルシクロヘキシル等、ただし本明細書においてアルキル基というときには通常シクロアルキル基を含む意味である。)、アリール基(好ましくは炭素原子数6~26のアリール基、例えば、フェニル、1-ナフチル、4-メトキシフェニル、2-クロロフェニル、3-メチルフェニル等)、アラルキル基(好ましくは炭素数7~23のアラルキル基、例えば、ベンジル、フェネチル等)、ヘテロ環基(好ましくは炭素原子数2~20のヘテロ環基、好ましくは、環構成原子として酸素原子、硫黄原子および窒素原子から選択される少なくとも1つを有する5又は6員環のヘテロ環基が好ましく、例えば、テトラヒドロピラニル、テトラヒドロフラニル、2-ピリジル、4-ピリジル、2-イミダゾリル、2-ベンゾイミダゾリル、2-チアゾリル、2-オキサゾリル、ピロリドン基等)、アルコキシ基(好ましくは炭素原子数1~20のアルコキシ基、例えば、メトキシ、エトキシ、イソプロピルオキシ、ベンジルオキシ等)、アリールオキシ基(好ましくは炭素原子数6~26のアリールオキシ基、例えば、フェノキシ、1-ナフチルオキシ、3-メチルフェノキシ、4-メトキシフェノキシ等、ただし本明細書においてアルコキシ基というときには通常アリーロイル基を含む意味である。)、アルコキシカルボニル基(好ましくは炭素原子数2~20のアルコキシカルボニル基、例えば、エトキシカルボニル、2-エチルヘキシルオキシカルボニル等)、アリールオキシカルボニル基(好ましくは炭素原子数6~26のアリールオキシカルボニル基、例えば、フェノキシカルボニル、1-ナフチルオキシカルボニル、3-メチルフェノキシカルボニル、4-メトキシフェノキシカルボニル等)、アミノ基(好ましくは炭素原子数0~20のアミノ基、アルキルアミノ基、アリールアミノ基を含み、例えば、アミノ、N,N-ジメチルアミノ、N,N-ジエチルアミノ、N-エチルアミノ、アニリノ等)、スルファモイル基(好ましくは炭素原子数0~20のスルファモイル基、例えば、N,N-ジメチルスルファモイル、N-フェニルスルファモイル等)、アシル基(好ましくは炭素原子数1~20のアシル基、例えば、アセチル、プロピオニル、ブチリル等)、アリーロイル基(好ましくは炭素原子数7~23のアリーロイル基、例えば、ベンゾイル等、ただし本明細書においてアシル基というときには通常アリーロイル基を含む意味である。)、アシルオキシ基(好ましくは炭素原子数1~20のアシルオキシ基、例えば、アセチルオキシ等)、アリーロイルオキシ基(好ましくは炭素原子数7~23のアリーロイルオキシ基、例えば、ベンゾイルオキシ等、ただし本明細書においてアシルオキシ基というときには通常アリーロイルオキシ基を含む意味である。)、カルバモイル基(好ましくは炭素原子数1~20のカルバモイル基、例えば、N,N-ジメチルカルバモイル、N-フェニルカルバモイル等)、アシルアミノ基(好ましくは炭素原子数1~20のアシルアミノ基、例えば、アセチルアミノ、ベンゾイルアミノ等)、アルキルスルファニル基(好ましくは炭素原子数1~20のアルキルスルファニル基、例えば、メチルスルファニル、エチルスルファニル、イソプロピルスルファニル、ベンジルスルファニル等)、アリールスルファニル基(好ましくは炭素原子数6~26のアリールスルファニル基、例えば、フェニルスルファニル、1-ナフチルスルファニル、3-メチルフェニルスルファニル、4-メトキシフェニルスルファニル等)、アルキルスルホニル基(好ましくは炭素原子数1~20のアルキルスルホニル基、例えば、メチルスルホニル、エチルスルホニル等)、アリールスルホニル基(好ましくは炭素原子数6~22のアリールスルホニル基、例えば、ベンゼンスルホニル等)、アルキルシリル基(好ましくは炭素原子数1~20のアルキルシリル基、例えば、モノメチルシリル、ジメチルシリル、トリメチルシリル、トリエチルシリル等)、アリールシリル基(好ましくは炭素原子数6~42のアリールシリル基、例えば、トリフェニルシリル等)、アルコキシシリル基(好ましくは炭素原子数1~20のアルコキシシリル基、例えば、モノメトキシシリル、ジメトキシシリル、トリメトキシシリル、トリエトキシシリル等)、アリールオキシシリル基(好ましくは炭素原子数6~42のアリールオキシシリル基、例えば、トリフェニルオキシシリル等)、ホスホリル基(好ましくは炭素原子数0~20のホスホリル基、例えば、-OP(=O)(RP)2)、ホスホニル基(好ましくは炭素原子数0~20のホスホニル基、例えば、-P(=O)(RP)2)、ホスフィニル基(好ましくは炭素原子数0~20のホスフィニル基、例えば、-P(RP)2)、(メタ)アクリロイル基、(メタ)アクリロイルオキシ基、(メタ)アクリロイルイミノ基((メタ)アクリルアミド基)、ヒドロキシ基、スルファニル基、カルボキシ基、リン酸基、ホスホン酸基、スルホン酸基、シアノ基、ハロゲン原子(例えばフッ素原子、塩素原子、臭素原子、ヨウ素原子等)が挙げられる。
また、これらの置換基Pで挙げた各基は、上記の置換基Pがさらに置換していてもよい。
化合物、置換基および連結基等がアルキル基、アルキレン基、アルケニル基、アルケニレン基、アルキニル基および/またはアルキニレン基等を含むとき、これらは環状でも鎖状でもよく、また直鎖でも分岐していてもよく、上記のように置換されていても無置換でもよい。
本発明の固体電解質組成物は分散剤を含有してもよい。分散剤を添加することで電極活物質及び無機固体電解質のいずれかの濃度が高い場合や、粒子径が細かく表面積が増大する場合においてもその凝集を抑制し、均一な活物質層及び固体電解質層を形成することができる。分散剤としては、全固体二次電池に通常使用されるものを適宜選定して用いることができる。一般的には粒子吸着と立体反発および/または静電反発を意図した化合物が好適に使用される。
本発明の固体電解質組成物は、リチウム塩を含有してもよい。
本発明に用いることができるリチウム塩としては、通常この種の製品に用いられるリチウム塩が好ましく、特に制限はないが、例えば、以下に述べるものが好ましい。
これらのなかで、LiPF6、LiBF4、LiAsF6、LiSbF6、LiClO4、Li(Rf1SO3)、LiN(Rf1SO2)2、LiN(FSO2)2、及びLiN(Rf1SO2)(Rf2SO2)が好ましく、LiPF6、LiBF4、LiN(Rf1SO2)2、LiN(FSO2)2、及びLiN(Rf1SO2)(Rf2SO2)などのリチウムイミド塩がさらに好ましい。ここで、Rf1、Rf2はそれぞれパーフルオロアルキル基を示す。
なお、リチウム塩は、1種を単独で使用しても、2種以上を任意に組み合わせてもよい。
本発明の固体電解質組成物は、固体電解質含有シートのイオン伝導度をより向上させるため、イオン液体を含有してもよい。イオン液体としては、特に限定されないが、イオン伝導度を効果的に向上させる観点から、上述したリチウム塩を溶解するものが好ましい。例えば、下記のカチオンと、アニオンとの組み合わせよりなる化合物が挙げられる。
カチオンとしては、以下の置換基を有するイミダゾリウムカチオン、以下の置換基を有するピリジニウムカチオン、以下の置換基を有するピペリジニウムカチオン、以下の置換基を有するピロリジニウムカチオン、以下の置換基を有するモルホリニウムカチオン、以下の置換基を有するホスホニウムカチオン、又は、以下の置換基を有する第4級アンモニウムカチオン等が挙げられる。
カチオンとしては、これらのカチオンを1種単独で用いてもよく、2種以上組み合わせて用いることもできる。
好ましくは、四級アンモニウムカチオン、ピペリジニウムカチオン又はピロリジニウムカチオンである。
置換基としては、アルキル基(炭素数1~8のアルキル基が好ましく、炭素数1~4のアルキル基がより好ましい。)、ヒドロキシアルキル基(炭素数1~3のヒドロキシアルキル基が好ましい。)、アルキルオキシアルキル基(炭素数2~8のアルキルオキシアルキル基が好ましく、炭素数2~4のアルキルオキシアルキル基がより好ましい。)、エーテル基、アリル基、アミノアルキル基(炭素数1~8のアミノアルキル基が好ましく、炭素数1~4のアミノアルキル基がより好ましい。)、アリール基(炭素数6~12のアリール基が好ましく、炭素数6~8のアリール基がより好ましい。)が挙げられる。上記置換基はカチオン部位を含有する形で環状構造を形成していてもよい。これらの置換基はさらに上記置換基Pを有していてもよい。なお、上記エーテル基は、他の置換基と組み合わされて用いられる。このような置換基として、アルキルオキシ基、アリールオキシ基等が挙げられる。
アニオンとしては、塩化物イオン、臭化物イオン、ヨウ化物イオン、四フッ化ホウ素イオン、硝酸イオン、ジシアナミドイオン、酢酸イオン、四塩化鉄イオン、ビス(トリフルオロメタンスルホニル)イミドイオン、ビス(フルオロスルホニル)イミドイオン、ビス(パーフルオロブチルメタンスルホニル)イミドイオン、アリルスルホネートイオン、ヘキサフルオロリン酸イオン、又は、トリフルオロメタンスルホネートイオン等が挙げられる。
アニオンとしては、これらのアニオンを1種単独で用いてもよく、2種以上組み合わせて用いることもできる。
好ましくは、四フッ化ホウ素イオン、ビス(トリフルオロメタンスルホニル)イミドイオン、ビス(フルオロスルホニル)イミドイオン、ヘキサフルオロリン酸イオン、ジシアナミドイオン又はアリルスルホネートイオンであり、さらに好ましくはビス(トリフルオロメタンスルホニル)イミドイオン、ビス(フルオロスルホニル)イミドイオン又はアリルスルホネートイオンである。
イオン液体の含有量は、無機固体電解質100質量部に対して0.1質量部以上が好ましく、0.5質量部以上がより好ましく、1質量部以上が特に好ましい。上限としては、50質量部以下が好ましく、20質量部以下がより好ましく、10質量部以下が特に好ましい。
リチウム塩とイオン液体の質量比は1:20~20:1が好ましく、1:10~10:1がより好ましく、1:5~2:1が特に好ましい。
本発明の固体電解質組成物は、導電助剤を含有してもよい。導電助剤としては、特に制限はなく、一般的な導電助剤として知られているものを用いることができる。例えば、電子伝導性材料である、天然黒鉛、人造黒鉛などの黒鉛類、アセチレンブラック、ケッチェンブラック、ファーネスブラックなどのカーボンブラック類、ニードルコークスなどの無定形炭素、気相成長炭素繊維やカーボンナノチューブなどの炭素繊維類、グラフェンやフラーレンなどの炭素質材料であっても良いし、銅、ニッケルなどの金属粉、金属繊維でも良く、ポリアニリン、ポリピロール、ポリチオフェン、ポリアセチレン、ポリフェニレン誘導体など導電性高分子を用いても良い。またこれらの内1種を用いても良いし、2種以上を用いても良い。
本発明の固体電解質組成物は、周期律表第1族又は第2族に属する金属元素のイオンの挿入放出が可能な活物質を含有してもよい。活物質としては、正極活物質及び負極活物質が挙げられ、正極活物質である遷移金属酸化物、又は、負極活物質である金属酸化物が好ましい。
本発明において、活物質(正極活物質、負極活物質)を含有する固体電解質組成物を、電極用組成物(正極用組成物、負極用組成物)ということがある。
本発明の固体電解質組成物が含有してもよい正極活物質は、可逆的にリチウムイオンを挿入および放出できるものが好ましい。その材料は、上記特性を有するものであれば、特に制限はなく、遷移金属酸化物や、有機物、硫黄などのLiと複合化できる元素や硫黄と金属の複合物などでもよい。
中でも、正極活物質としては、遷移金属酸化物を用いることが好ましく、遷移金属元素Ma(Co、Ni、Fe、Mn、CuおよびVから選択される1種以上の元素)を有する遷移金属酸化物がより好ましい。また、この遷移金属酸化物に元素Mb(リチウム以外の金属周期律表の第1(Ia)族の元素、第2(IIa)族の元素、Al、Ga、In、Ge、Sn、Pb、Sb、Bi、Si、PまたはBなどの元素)を混合してもよい。混合量としては、遷移金属元素Maの量(100mol%)に対して0~30mol%が好ましい。Li/Maのモル比が0.3~2.2になるように混合して合成されたものが、より好ましい。
遷移金属酸化物の具体例としては、(MA)層状岩塩型構造を有する遷移金属酸化物、(MB)スピネル型構造を有する遷移金属酸化物、(MC)リチウム含有遷移金属リン酸化合物、(MD)リチウム含有遷移金属ハロゲン化リン酸化合物および(ME)リチウム含有遷移金属ケイ酸化合物等が挙げられる。
(MB)スピネル型構造を有する遷移金属酸化物の具体例として、LiMn2O4(LMO)、LiCoMnO4、Li2FeMn3O8、Li2CuMn3O8、Li2CrMn3O8およびLi2NiMn3O8が挙げられる。
(MC)リチウム含有遷移金属リン酸化合物としては、例えば、LiFePO4およびLi3Fe2(PO4)3等のオリビン型リン酸鉄塩、LiFeP2O7等のピロリン酸鉄類、LiCoPO4等のリン酸コバルト類ならびにLi3V2(PO4)3(リン酸バナジウムリチウム)等の単斜晶ナシコン型リン酸バナジウム塩が挙げられる。
(MD)リチウム含有遷移金属ハロゲン化リン酸化合物としては、例えば、Li2FePO4F等のフッ化リン酸鉄塩、Li2MnPO4F等のフッ化リン酸マンガン塩およびLi2CoPO4F等のフッ化リン酸コバルト類が挙げられる。
(ME)リチウム含有遷移金属ケイ酸化合物としては、例えば、Li2FeSiO4、Li2MnSiO4およびLi2CoSiO4等が挙げられる。
本発明では、(MA)層状岩塩型構造を有する遷移金属酸化物が好ましく、LCO、LMO、NCA又はNMCがより好ましい。
正極活物質層を形成する場合、正極活物質層の単位面積(cm2)当たりの正極活物質の質量(mg)(目付量)は特に限定されるものではない。設計された電池容量に応じて、適宜に決めることができる。
本発明の固体電解質組成物が含有してもよい負極活物質は、可逆的にリチウムイオンを挿入および放出できるものが好ましい。その材料は、上記特性を有するものであれば、特に制限はなく、炭素質材料、酸化錫等の金属酸化物、酸化ケイ素、金属複合酸化物、リチウム単体およびリチウムアルミニウム合金等のリチウム合金、並びに、Sn、Si、AlおよびIn等のリチウムと合金形成可能な金属等が挙げられる。中でも、炭素質材料又はリチウム複合酸化物が信頼性の点から好ましく用いられる。また、金属複合酸化物としては、リチウムを吸蔵および放出可能であることが好ましい。その材料は、特には制限されないが、構成成分としてチタン及び/又はリチウムを含有していることが、高電流密度充放電特性の観点で好ましい。
負極活物質層を形成する場合、負極活物質層の単位面積(cm2)当たりの負極活物質の質量(mg)(目付量)は特に限定されるものではない。設計された電池容量に応じて、適宜に決めることができる。
また、正極活物質または負極活物質を含む電極表面は硫黄またはリンで表面処理されていてもよい。
さらに、正極活物質または負極活物質の粒子表面は、上記表面被覆の前後において活性光線または活性気体(プラズマ等)により表面処理を施されていても良い。
本発明の固体電解質組成物は、無機固体電解質(A)およびバインダー(B)を分散媒体(C)の存在下で分散して、スラリー化することで調製することができる。
スラリー化は、各種の混合機を用いて無機固体電解質と、バインダーと、分散媒体とを混合することにより行うことができる。混合装置としては、特に限定されないが、例えば、ボールミル、ビーズミル、プラネタリミキサ―、ブレードミキサ―、ロールミル、ニーダーおよびディスクミルが挙げられる。混合条件は特に制限されないが、例えば、ボールミルを用いた場合、150~700rpm(rotation per minute)で1時間~24時間混合することが好ましい。
活物質、粒子分散剤等の成分を含有する固体電解質組成物を調製する場合には、上記の無機固体電解質(A)およびバインダー(B)の分散工程と同時に添加及び混合してもよく、別途添加及び混合してもよい。
本発明の固体電解質含有シートは、周期律表第1族又は第2族に属する金属のイオンの伝導性を有する無機固体電解質(A)とバインダー(B)とを含有し、分散媒体(C)を全質量中1ppm以上10000ppm以下含有する。上記分散媒体(C)は、炭素原子と、水素原子および/またはハロゲン原子とで構成された脂環式化合物(C1)を含み、760mmHgにおける脂環式化合物(C1)の沸点が100℃以上180℃以下である。
全固体二次電池用固体電解質シートとして、例えば、固体電解質層と保護層とを基材上に、この順で有するシートが挙げられる。
基材としては、固体電解質層を支持できるものであれば特に限定されず、後記集電体で説明した材料、有機材料および無機材料等のシート体(板状体)等が挙げられる。有機材料としては、各種ポリマー等が挙げられ、具体的には、ポリエチレンテレフタレート、ポリプロピレン、ポリエチレンおよびセルロース等が挙げられる。無機材料としては、例えば、ガラスおよびセラミック等が挙げられる。
このシートは、本発明の固体電解質組成物を基材上(他の層を介していてもよい)に製膜(塗布乾燥)して、基材上に固体電解質層を形成することにより、得られる。
ここで、本発明の固体電解質組成物は、上記の方法によって、調製できる。
電極シートを構成する各層の構成および層厚は、上述の、本発明の全固体二次電池において説明した各層の構成および層厚と同じである。
電極シートは、本発明の、活物質を含有する固体電解質組成物を金属箔上に製膜(塗布乾燥)して、金属箔上に活物質層を形成することにより、得られる。活物質を含有する固体電解質組成物を調製する方法は、活物質を用いること以外は、上記固体電解質組成物を調製する方法と同じである。
本発明の全固体二次電池は、正極と、この正極に対向する負極と、正極及び負極の間の固体電解質層とを有する。正極は、正極集電体上に正極活物質層を有する。負極は、負極集電体上に負極活物質層を有する。
負極活物質層、正極活物質層及び固体電解質層の少なくとも1つの層は、本発明の固体電解質組成物を用いて形成されることが好ましい。
固体電解質組成物で形成された活物質層および/または固体電解質層は、好ましくは、含有する成分種及びその含有量比について、固体電解質組成物の固形分におけるものと同じである。
以下に、図1を参照して、本発明の好ましい実施形態について説明するが、本発明はこれに限定されない。
全固体二次電池10においては、正極活物質層、固体電解質層及び負極活物質層のいずれかが本発明の固体電解質組成物を用いて形成されている。
すなわち、固体電解質層3が本発明の固体電解質組成物で形成されている場合、固体電解質層3は、無機固体電解質とバインダーとを含む。固体電解質層は、通常、正極活物質及び/又は負極活物質を含まない。固体電解質層3中では、バインダーが、無機固体電解質および隣接する活物質層中に含まれる活物質等の固体粒子の間に存在していると考えられる。そのため、固体粒子間の界面抵抗が低減され、結着性が高くなっている。
正極活物質層4、固体電解質層3及び負極活物質層2が含有する無機固体電解質及びバインダーは、それぞれ、互いに同種であっても異種であってもよい。
正極集電体5及び負極集電体1は、電子伝導体が好ましい。
本発明において、正極集電体及び負極集電体のいずれか、又は、両方を合わせて、単に、集電体と称することがある。
正極集電体を形成する材料としては、アルミニウム、アルミニウム合金、ステンレス鋼、ニッケルおよびチタンなどの他に、アルミニウムまたはステンレス鋼の表面にカーボン、ニッケル、チタンあるいは銀を処理させたもの(薄膜を形成したもの)が好ましく、その中でも、アルミニウムおよびアルミニウム合金がより好ましい。
負極集電体を形成する材料としては、アルミニウム、銅、銅合金、ステンレス鋼、ニッケルおよびチタンなどの他に、アルミニウム、銅、銅合金またはステンレス鋼の表面にカーボン、ニッケル、チタンあるいは銀を処理させたものが好ましく、アルミニウム、銅、銅合金およびステンレス鋼がより好ましい。
集電体の厚みは、特に限定されないが、1~500μmが好ましい。また、集電体表面は、表面処理により凹凸を付けることも好ましい。
上記の各層を配置して全固体二次電池の基本構造を作製することができる。用途によってはこのまま全固体二次電池として使用してもよいが、乾電池の形態とするためにはさらに適当な筐体に封入して用いる。筐体は、金属性のものであっても、樹脂(プラスチック)製のものであってもよい。金属性のものを用いる場合には、例えば、アルミニウム合金およびステンレス鋼製のものを挙げることができる。金属性の筐体は、正極側の筐体と負極側の筐体に分けて、それぞれ正極集電体及び負極集電体と電気的に接続させることが好ましい。正極側の筐体と負極側の筐体とは、短絡防止用のガスケットを介して接合され、一体化されることが好ましい。
本発明の固体電解質含有シートは、本発明の固体電解質組成物を基材上(他の層を介していてもよい)に製膜(塗布乾燥)して、基材上に固体電解質層を形成することにより、得られる。
上記態様により、基材と固体電解質層とを有するシートである全固体二次電池用シートを作製することができる。
その他、塗布等の工程については、下記全固体二次電池の製造に記載の方法を使用することができる。
固体電解質含有シートを20mm角で打ち抜き、ガラス瓶中で重テトラヒドロフランに浸漬させる。得られた溶出物をシリンジフィルターでろ過して1H-NMRにより定量操作を行う。1H-NMRピーク面積と溶媒の量の相関性は検量線を作成して求める。
全固体二次電池及び全固体二次電池用電極シートの製造は、常法によって行うことができる。具体的には、全固体二次電池及び全固体二次電池用電極シートは、本発明の固体電解質組成物等を用いて、上記の各層を形成することにより、製造できる。以下詳述する。
例えば、正極集電体である金属箔上に、正極用材料(正極用組成物)として、正極活物質を含有する固体電解質組成物を塗布して正極活物質層を形成し、全固体二次電池用正極シートを作製する。次いで、この正極活物質層の上に、固体電解質層を形成するための固体電解質組成物を塗布して、固体電解質層を形成する。さらに、固体電解質層の上に、負極用材料(負極用組成物)として、負極活物質を含有する固体電解質組成物を塗布して、負極活物質層を形成する。負極活物質層の上に、負極集電体(金属箔)を重ねることにより、正極活物質層と負極活物質層の間に固体電解質層が挟まれた構造の全固体二次電池を得ることができる。必要によりこれを筐体に封入して所望の全固体二次電池とすることができる。
また、各層の形成方法を逆にして、負極集電体上に、負極活物質層、固体電解質層及び正極活物質層を形成し、正極集電体を重ねて、全固体二次電池を製造することもできる。
また別の方法として、次の方法が挙げられる。すなわち、上記のようにして、全固体二次電池用正極シート及び全固体二次電池用負極シートを作製する。また、これとは別に、固体電解質組成物を基材上に塗布して、固体電解質層からなる全固体二次電池用固体電解質シートを作製する。さらに、全固体二次電池用正極シート及び全固体二次電池用負極シートで、基材から剥がした固体電解質層を挟むように積層する。このようにして、全固体二次電池を製造することができる。
固体電解質組成物の塗布方法は、特に限定されず、適宜に選択できる。例えば、塗布(好ましくは湿式塗布)、スプレー塗布、スピンコート塗布、ディップコート、スリット塗布、ストライプ塗布およびバーコート塗布が挙げられる。
このとき、固体電解質組成物は、それぞれ塗布した後に乾燥処理を施してもよいし、重層塗布した後に乾燥処理をしてもよい。乾燥温度は特に限定されない。下限は30℃以上が好ましく、60℃以上がより好ましく、80℃以上がさらに好ましい。上限は、300℃以下が好ましく、250℃以下がより好ましく、200℃以下がさらに好ましい。このような温度範囲で加熱することで、分散媒体を除去し、固体状態にすることができる。また、温度を高くしすぎず、全固体二次電池の各部材を損傷せずに済むため好ましい。これにより、全固体二次電池において、優れた総合性能を示し、かつ良好な結着性を得ることができる。
また、塗布した固体電解質組成物は、加圧と同時に加熱してもよい。加熱温度としては、特に限定されず、一般的には30~300℃の範囲である。無機固体電解質のガラス転移温度よりも高い温度でプレスすることもできる。
加圧は塗布溶媒又は分散媒体をあらかじめ乾燥させた状態で行ってもよいし、溶媒又は分散媒体が残存している状態で行ってもよい。
なお、各組成物は同時に塗布しても良いし、塗布乾燥プレスを同時および/または逐次行っても良い。別々の基材に塗布した後に、転写により積層してもよい。
プレス時間は短時間(例えば数時間以内)で高い圧力をかけてもよいし、長時間(1日以上)かけて中程度の圧力をかけてもよい。全固体二次電池用シート以外、例えば全固体二次電池の場合には、中程度の圧力をかけ続けるために、全固体二次電池の拘束具(ネジ締め圧等)を用いることもできる。
プレス圧はシート面等の被圧部に対して均一であっても異なる圧であってもよい。
プレス圧は被圧部の面積や膜厚に応じて変化させることができる。また同一部位を段階的に異なる圧力で変えることもできる。
プレス面は平滑であっても粗面化されていてもよい。
上記のようにして製造した全固体二次電池は、製造後又は使用前に初期化を行うことが好ましい。初期化は、特に限定されず、例えば、プレス圧を高めた状態で初充放電を行い、その後、全固体二次電池の一般使用圧力になるまで圧力を開放することにより、行うことができる。
本発明の全固体二次電池は種々の用途に適用することができる。適用態様には特に限定はないが、例えば、電子機器に搭載する場合、ノートパソコン、ペン入力パソコン、モバイルパソコン、電子ブックプレーヤー、携帯電話、コードレスフォン子機、ページャー、ハンディーターミナル、携帯ファックス、携帯コピー、携帯プリンター、ヘッドフォンステレオ、ビデオムービー、液晶テレビ、ハンディークリーナー、ポータブルCD、ミニディスク、電気シェーバー、トランシーバー、電子手帳、電卓、携帯テープレコーダー、ラジオ、バックアップ電源、メモリーカードなどが挙げられる。その他民生用として、自動車(電気自動車等)、電動車両、モーター、照明器具、玩具、ゲーム機器、ロードコンディショナー、時計、ストロボ、カメラ、医療機器(ペースメーカー、補聴器、肩もみ機など)などが挙げられる。更に、各種軍需用、宇宙用として用いることができる。また、太陽電池と組み合わせることもできる。
〔1〕正極活物質層、固体電解質層および負極活物質層の少なくとも1層がリチウム塩を含有する全固体二次電池。
〔2〕固体電解質層が、分散媒体によって、リチウム塩および硫化物系無機固体電解質が分散されたスラリーを湿式塗布し製膜される全固体二次電池の製造方法。
〔3〕上記全固体二次電池作製用の活物質を含有する固体電解質組成物。
〔4〕上記固体電解質組成物を金属箔上に適用し、製膜してなる電池用電極シート。
〔5〕上記固体電解質組成物を金属箔上に適用し、製膜する電池用電極シートの製造方法。
無機固体電解質とは、上述した高分子化合物をイオン伝導媒体とする電解質(高分子電解質)とは区別されるものであり、無機化合物がイオン伝導媒体となるものである。具体例としては、上記のLi-P-S系ガラス、LLTやLLZが挙げられる。無機固体電解質は、それ自体が陽イオン(Liイオン)を放出するものではなく、イオンの輸送機能を示すものである。これに対して、電解液ないし固体電解質層に添加して陽イオン(Liイオン)を放出するイオンの供給源となる材料を電解質と呼ぶことがある。上記のイオン輸送材料としての電解質と区別する際には、これを「電解質塩」または「支持電解質」と呼ぶ。電解質塩としては、例えばLiTFSIが挙げられる。
本発明において「組成物」というときには、2種以上の成分が均一に混合された混合物を意味する。ただし、実質的に均一性が維持されていればよく、所望の効果を奏する範囲で、一部において凝集や偏在が生じていてもよい。
-Li-P-S系ガラスの合成-
硫化物系無機固体電解質として、T.Ohtomo,A.Hayashi,M.Tatsumisago,Y.Tsuchida,S.HamGa,K.Kawamoto,Journal of Power Sources,233,(2013),pp231-235およびA.Hayashi,S.Hama,H.Morimoto,M.Tatsumisago,T.Minami,Chem.Lett.,(2001),pp872-873の非特許文献を参考にして、Li-P-S系ガラスを合成した。
ジルコニア製45mL容器(フリッチュ社製)に、直径5mmのジルコニアビーズを66個投入し、上記硫化リチウムと五硫化二リンの混合物全量を投入し、アルゴン雰囲気下で容器を密閉した。フリッチュ社製の遊星ボールミルP-7(商品名)にこの容器をセットし、温度25℃、回転数510rpmで20時間メカニカルミリングを行い、黄色粉体の硫化物系無機固体電解質(Li-P-S系ガラス)6.20gを得た。イオン伝導度は0.28mS/cm、体積平均粒子径は20.3μmであった。
(固体電解質組成物に添加する前の無機固体電解質の体積平均粒子径の測定)
JIS8826:2005に準じた動的光散乱式粒径分布測定装置(株式会社堀場製作所製、商品名:LB-500)を用いて、上記合成した硫化物系無機固体電解質粒子を20mlサンプル瓶に分取し、トルエンにより固形分濃度が0.2質量%になるように希釈調整し、温度25℃で2mlの測定用石英セルを使用してデータ取り込みを50回行い、得られた体積基準の算術平均を平均粒子径とした。また、累積粒度分布の微粒子側からの累積50%の粒子径を累積50%粒子径とした。混合前の粒子の平均粒子径はこの方法で測定した。
<試験および測定>
後記調製した固体電解質組成物について、分散安定性試験、粘度の測定、固体電解質組成物中の無機固体電解質の体積平均粒子径の測定およびイオン伝導度の測定を行った。試験および測定結果を下記表1にまとめて記載する。
また、下記で調製した正極用組成物および負極用組成物について分散安定性試験および粘度の測定を行った。試験および測定結果を下記表2および3にまとめて記載する。
以下、試験方法および測定方法を記載する。
下記各組成物を調製後、透明サンプル瓶中に25℃で24時間静置した。24時間静置前後の各組成物の状態を目視により観察した。24時間静置前の各組成物の固形成分と、24時間静置後の各組成物の固形成分と目視により観察し、下記評価基準で評価した。以下に評価基準を示す。ランクA~Cが合格レベルである。
<評価基準>
A:変化(沈降)が観察されなかった。
B:沈降した固形成分の割合が10%以下
C:沈降した固形成分の割合が10%を超え30%以下
D:沈降した固形成分の割合が30%を超え80%以下
E:沈降した固形成分の割合が80%超
回転式粘度計(RE-85型(東機産業製))を用いて調製したスラリーである各組成物の20℃における粘度を測定した。
(固体電解質組成物中の無機固体電解質の体積平均粒子径の測定)
JIS8826:2005に準じた動的光散乱式粒径分布測定装置(株式会社堀場製作所製、商品名:LB-500)を用いて、固体電解質組成物を20mlサンプル瓶に分取し、トルエンにより固形分濃度が0.2質量%になるように希釈調整し、温度25℃で2mlの測定用石英セルを使用してデータ取り込みを50回行い、得られた体積基準の算術平均を平均粒子径とした。また、累積粒度分布の微粒子側からの累積50%の粒子径を累積50%粒子径とした。固体電解質組成物中の無機固体電解質粒子の平均粒子径はこの方法で測定した。
結果を下記表1にまとめて示す。
固体電解質組成物のスラリーを露点-60℃の乾燥空気下で、100℃に加熱したホットプレート上で2時間常圧乾燥を行った。得られた乾燥粉末をインピーダンス法によりイオン伝導度を測定した。
乾燥粉末を直径14.5mmの円筒に300mg詰め、コイン型冶具を作製した。コイン型冶具の外部より、電極間に500kgf/cm2の圧力をかけることが可能なジグに挟み、イオン伝導度の測定に用いた。
上記で得られたコイン型冶具を用いて、30℃の恒温槽中、交流インピーダンス法により、加圧(500kgf/cm2)でのイオン伝導度を求めた。このとき、コイン型冶具の加圧には図2に示した試験体を用いた。11が上部支持板、12が下部支持板、13がコイン型冶具、Sがネジである。
-固体電解質組成物S-1の調製-
ジルコニア製45mL容器(フリッチュ社製)に、直径3mmのジルコニアビーズを50個投入し、酸化物系無機固体電解質LLZ(豊島製作所製)1.5g、バインダー(B-1)0.020gを加え、分散媒体として、エチルシクロヘキサン5.3gを投入した。その後、フリッチュ社製遊星ボールミルP-7(商品名)に容器をセットし、温度25℃、回転数300rpmで2時間混合を続け、固体電解質組成物S-1を調製した。
ジルコニア製45mL容器(フリッチュ社製)に、直径3mmのジルコニアビーズを50個投入し、上記で合成した硫化物系無機固体電解質Li-P-S系ガラス0.8g、バインダー(B-1)0.040g、分散媒体としてエチルシクロヘキサン3.6gを投入した。その後、この容器を遊星ボールミルP-7(フリッチュ社製)にセットし、温度25℃、回転数300rpmで2時間攪拌を続け、固体電解質組成物S-2を調製した。
下記表1に記載の組成に変えた以外は、上記固体電解質組成物S-1またはS-2と同様の方法で、固体電解質組成物S-3~S-19およびT-1およびT-4を調製した。
ここで、固体電解質組成物S-1~S-19が本発明の固体電解質組成物であり、固体電解質組成物T-1~T-4が比較の固体電解質組成物である。
B-1:PVdF-HFP(アルケマ社製)
B-2:SBR(JSR社製)
B-3:下記の方法で調製したアクリル酸-アクリル酸メチル共重合体(20/80モル比 Mw25000)
100mL3つ口フラスコにアクリル酸(和光純薬(株)製)1.2gとアクリル酸メチル4.2g(和光純薬(株)製)をMEK(メチルエチルケトン)30gに溶解し、75℃に加熱しながら窒素置換した。これにアゾイソブチロニトリル(V-60:商品名、和光純薬(株)製)0.15gを添加して、窒素雰囲気下75℃で6時間加熱した。得られたポリマー溶液を、ヘキサンを用いてポリマー沈殿させて白色粉末を得た。
B-4:アクリルラテックス特開2015-88486号公報記載のバインダー(B-1)、平均粒子径:450μm(分散媒体:エチルシクロヘキサン)、平均粒子径:180μm(分散媒体:クロロシクロヘキサン)
B-5:ウレタンポリマー特開2015-88480号公報記載の例示化合物(44)
(バインダーの平均粒子径は、分散媒体中に粒子状で存在するもののみ記載している。)
LLZ:Li7La3Zr2O12(豊島製作所製)
Li/P/S:上記で合成したLi-P-S系ガラス
脂環式化合物(C1)の沸点(℃)は760mmHgにおける沸点を、脂環式化合物(C1)の粘度(mPa・s)は20℃における粘度を示す。
本発明の固体電解質組成物との対比のため、T-1~T-4で用いた分散媒体の一部を脂環式化合物(C1)の列に記載した。
LiTFSI:リチウムビス(トリフルオロメタンスルホニル)イミド
TMBATFSI:トリメチルブ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
EMImTFSI:1-エチル-3-メチルイミダゾリウムビス(トリフルオロメタンスルホニル)イミド
粒子径:無機固体電解質の体積平均粒子径を意味する。
ジルコニア製45mL容器(フリッチュ社製)に、直径3mmのジルコニアビーズを50個投入し、上記で合成した無機固体電解質組成物(S-1)6.8gを加えた。これに正極活物質LCOを3.2g加え、その後、この容器を遊星ボールミルP-7(フリッチュ社製)にセットし、温度25℃、回転数100rpmで10分間攪拌を続け、正極用固体電解質組成物P-1を調製した。
ここで、正極用固体電解質組成物P-1~P-19が本発明の固体電解質組成物であり、正極用固体電解質組成物HP-1~HP-4が比較の固体電解質組成物である。
LCO:LiCoO2
LMO:LiMn2O4
NCA:LiNi0.85Co0.10Al0.05O2
NMC:LiNi1/3Co1/3Mn1/3O2
AB:アセチレンブラック
ジルコニア製45mL容器(フリッチュ社製)に、直径3mmのジルコニアビーズを50個投入し、上記で合成した無機固体電解質組成物(S-1)6.8gを加えた。これに負極活物質としてLTO(Li4Ti5O12)を3.2g加え、その後、この容器を遊星ボールミルP-7(フリッチュ社製)にセットし、温度25℃、回転数100rpmで10分間攪拌を続け、負極用固体電解質組成物N-1を調製した。
下記表3に、負極用固体電解質組成物の組成をまとめて記載する。
ここで、負極用固体電解質組成物N-1~N-17が本発明の固体電解質組成物であり、負極用固体電解質組成物HN-1~HN-4が比較の固体電解質組成物である。
LTO:Li4Ti5O12
上記正極用固体電解質組成物P-1のスラリーを厚み40μmのアルミ箔上に、アプリケーター(商品名SA-201ベーカー式アプリケータ、テスター産業社製)により塗布し、ヒートプレス機を用いて120℃で1時間加熱して分散媒体を除去し、厚さ約160μmの全固体二次電池用電極シートPS-1(正極用電極シートPS-1)を得た。
同様にして、正極用電極シートPS-2~PS-19およびHPS-1~HPS-4を作製した。
下記表4において、正極層PS-1~PS-19およびHPS-1~HPS-4は、全固体二次電池の正極層が、それぞれ正極用電極シートPS-1~PS-19およびHPS-1~HPS-4の正極層であることを意味する。
下記表4において、固体電解質層S-1~S-19およびHS-1~HS-4は、全固体二次電池の固体電解質層が、それぞれ全固体二次電池用固体電解質シートS-1~S-19およびHS-1~HS-4の固体電解質層であることを意味する。
下記表4において、負極層NS-1~NS-17およびHNS-1~HNS-4は、全固体二次電池の負極層が、それぞれ負極用電極シートNS-1~NS-17およびHNS-1~HNS-4の負極層であることを意味する。
上記で作製した全固体二次電池用固体電解質シートおよび全固体二次電池用電極シートについて層厚均一性試験を行った。以下、試験方法を記載する。また、結果を下記表4にまとめて記載する。
得られた全固体二次電池用固体電解質シートおよび全固体二次電池用電極シートについて25mm四方で打ち抜きこれをサンプルとした。このサンプルの9点(縦3点×横3点)の層厚を層厚計を用いて測りその平均値と標準偏差を求め、下記評価基準で評価した。
各組成物から得られるシートが、ぞれぞれ均一な厚みを有すると、シート製造において塗布ムラによる欠陥が抑制でき、上記シートを電極に組み込んで作動させた際の短絡抑制効果が期待できる。ランクA~Cが合格レベルである。
A:(標準偏差/平均)<5%
B:5%≦(標準偏差/平均)<10%
C:10%≦(標準偏差/平均)<20%
D:20%≦(標準偏差/平均)<50%
E:50%≦(標準偏差/平均)
固体電解質組成物S-1をテフロン(登録商標)シート上に、アプリケーター(商品名:SA-201ベーカー式アプリケーター、テスター産業社製)により塗布し120℃で0.1時間乾燥した。これを上記で得られた正極用電極シートPS-1に貼り合わせテフロンシートを除去した。この固体電解質層側に上記で得られた負極用電極シートNS-1を貼り合わせ、プレス機を用いて300MPaで5秒間プレスした。
図3に示すように、上記で製造した全固体二次電池用電極シート16を直径14.5mmの円板状に切り出し、スペーサーとワッシャー(ともに図3において図示しない)を組み込んだステンレス製の2032型コインケース16に入れて、トルクレンチで8ニュートン(N)の力で締め付け、図1に示す層構成を有する全固体二次電池18を製造した。
上記で作製した実施例及び比較例の全固体二次電池に対して以下の電圧評価を行った。評価結果は、後記表4に示す。
充電は、電流密度2A/m2で電池電圧が4.2Vに達するまで行い、4.2Vに到達後は、電流密度が0.2A/m2未満となるまで、定電圧充電を実施した。放電は、電流密度2A/m2で電池電圧が3.0Vに達するまで行った。これを1サイクルとして3サイクル繰り返して行い、3サイクル目の5mAh/g放電後の電池電圧を読み取り、以下の基準で評価した。なお、ランクA~Cが合格レベルである。
A:4.0V以上
B:3.9V以上4.0V未満
C:3.8V以上3.9V未満
D:3.7V以上3.8V未満
E:3.7V未満
これに対して、電池No.101~119の結果から明らかなように、本発明の固体電解質組成物を用いて作製した全固体二次電池用シートは、層厚均一性に優れた。イオン伝導度が高い全固体二次電池用シートを用いた本発明の全固体二次電池は電池電圧が高かった。
2 負極活物質層
3 固体電解質層
4 正極活物質層
5 正極集電体
6 作動部位
10 全固体二次電池
11 上部支持板
12 下部支持板
13 コイン型冶具
14 コインケース
15 固体電解質含有シート
S ネジ
16 2032型コインケース
17 全固体二次電池用電極シート
18 全固体二次電池
Claims (18)
- 周期律表第1族又は第2族に属する金属のイオンの伝導性を有する無機固体電解質(A)と、バインダー(B)と、分散媒体(C)とを含有する固体電解質組成物であって、
前記分散媒体(C)が、炭素原子と、水素原子および/またはハロゲン原子とで構成された脂環式化合物(C1)を含み、760mmHgにおける該脂環式化合物(C1)の沸点が100℃以上180℃以下である固体電解質組成物。 - 前記脂環式化合物(C1)が、環内に不飽和結合を含まず、かつ、単環状である請求項1に記載の固体電解質組成物。
- 前記脂環式化合物(C1)が、炭素数2以上のアルキル基、アルケニル基、アルキニル基およびハロゲン原子からなる群から選択される少なくとも1種を有する請求項1または2に記載の固体電解質組成物。
- 前記脂環式化合物(C1)が、6~8員環の化合物である請求項1~3のいずれか1項に記載の固体電解質組成物。
- 前記分散媒体(C)中の、前記脂環式化合物(C1)の割合が20質量%~100質量%である請求項1~4のいずれか1項に記載の固体電解質組成物。
- 前記無機固体電解質(A)が、硫化物系無機固体電解質である請求項1~5のいずれか1項に記載の固体電解質組成物。
- 前記バインダー(B)が、アクリル樹脂、ポリウレタン樹脂、ポリウレア樹脂、ポリイミド樹脂、含フッ素樹脂および炭化水素系熱可塑性樹脂からなる群から選択される少なくとも1種である請求項1~6のいずれか1項に記載の固体電解質組成物。
- 前記バインダー(B)が極性基を有する請求項1~7のいずれか1項に記載の固体電解質組成物。
- 前記バインダー(B)が分散媒体(C)に対して不溶の粒子である請求項1~8のいずれか1項に記載の固体電解質組成物。
- 前記バインダー(B)が、平均粒子径10~1000nmのナノ粒子である請求項9に記載の固体電解質組成物。
- 活物質(D)を含有する請求項1~10のいずれか1項に記載の固体電解質組成物。
- 導電助剤を含有する請求項1~11のいずれか1項に記載の固体電解質組成物。
- リチウム塩を含有する請求項1~12のいずれか1項に記載の固体電解質組成物。
- イオン液体を含有する請求項1~13のいずれか1項に記載の固体電解質組成物。
- 周期律表第1族又は第2族に属する金属のイオンの伝導性を有する無機固体電解質(A)とバインダー(B)とを含有し、分散媒体(C)を全質量中1ppm以上10000ppm以下含有する固体電解質含有シートであって、前記分散媒体(C)が、炭素原子と、水素原子および/またはハロゲン原子とで構成された脂環式化合物(C1)を含み、760mmHgにおける前記脂環式化合物(C1)の沸点が100℃以上180℃以下である固体電解質含有シート。
- 請求項1~14のいずれか1項に記載の固体電解質組成物を基材上に塗布し、塗膜を形成する工程を含む固体電解質含有シートの製造方法。
- 正極活物質層、負極活物質層および固体電解質層を具備する全固体二次電池であって、
前記正極活物質層、前記負極活物質層および前記固体電解質層の少なくとも1つの層が請求項15に記載の固体電解質含有シートである全固体二次電池。 - 請求項16に記載の製造方法を介して、全固体二次電池を製造する全固体二次電池の製造方法。
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WO2019151363A1 (ja) * | 2018-02-05 | 2019-08-08 | 富士フイルム株式会社 | 固体電解質含有シート、全固体二次電池用電極シート、全固体二次電池、電子機器及び電気自動車、並びに、これらの製造方法 |
JPWO2019151363A1 (ja) * | 2018-02-05 | 2020-10-22 | 富士フイルム株式会社 | 固体電解質含有シート、全固体二次電池用電極シート、全固体二次電池、電子機器及び電気自動車、並びに、これらの製造方法 |
CN110299560A (zh) * | 2018-03-22 | 2019-10-01 | 丰田自动车株式会社 | 硫化物固体电池 |
WO2020203367A1 (ja) * | 2019-03-29 | 2020-10-08 | 富士フイルム株式会社 | 全固体二次電池用シート及び全固体二次電池の製造方法、並びに、全固体二次電池用シート及び全固体二次電池 |
JPWO2020203367A1 (ja) * | 2019-03-29 | 2021-10-14 | 富士フイルム株式会社 | 全固体二次電池用シート及び全固体二次電池の製造方法、並びに、全固体二次電池用シート及び全固体二次電池 |
JP7078801B2 (ja) | 2019-03-29 | 2022-05-31 | 富士フイルム株式会社 | 全固体二次電池用シート及び全固体二次電池の製造方法、並びに、全固体二次電池用シート及び全固体二次電池 |
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EP3467846A4 (en) | 2019-06-26 |
JPWO2017204028A1 (ja) | 2019-03-14 |
JP6665284B2 (ja) | 2020-03-13 |
KR20190002550A (ko) | 2019-01-08 |
CN109155162B (zh) | 2021-06-11 |
KR102244414B1 (ko) | 2021-04-23 |
CN109155162A (zh) | 2019-01-04 |
US20190088994A1 (en) | 2019-03-21 |
EP3467846A1 (en) | 2019-04-10 |
EP3467846B1 (en) | 2020-06-03 |
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