Electrode mixture slurry for solid state battery and method for manufacturing electrode mixture slurry

Abstract

To provide an electrode mixture slurry for a solid state battery that suppresses gelation, and a method for manufacturing the same.SOLUTION: An electrode mixture slurry for a solid state battery includes an electrode active material, a solid electrolyte, a conductive additive, a binder, and a dispersant, and the electrode mixture slurry has a storage modulus that is smaller than a loss modulus of the electrode mixture slurry over an entire range of shear strain from 0.01% to 1,000%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electrode mixture slurry for a solid-state battery and a method for producing the electrode mixture slurry. [Background technology]

[0002] The electrode mixture slurry used in solid-state batteries is a slurry containing an electrode active material, a solid electrolyte, etc. The electrode mixture slurry is applied to the surface of a substrate, dried, and pressed as necessary to form an electrode active material layer. The following slurries with improved dispersibility are known:

[0003] For example, Patent Document 1 discloses a method for producing a silicon particle dispersion containing a solvent, silicon particles, a solid electrolyte, and a dispersant, the solvent including a low polarity solvent having a polarity term ΔP of the Hansen solubility parameter of 4 or less, the dispersant including a first dispersant having a basic functional group, and the silicon particles having a peak at 1600±10 cm in an FT-IR spectrum after pyridine adsorption. -1 Range: 1400±10cm -1 The slurry disclosed in Patent Document 1 is said to be capable of improving dispersibility. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-103642 Summary of the Invention [Problem to be solved by the invention]

[0005] The electrode mixture slurry is a slurry in which solids such as an electrode active material, a solid electrolyte, and a conductive additive are dispersed, and the dispersion state of the solids is stabilized by the presence of a binder and a dispersant. The performance of the electrode active material layer mainly depends on the solid composition of the electrode mixture slurry, and depending on the solid composition of the electrode mixture slurry, flocculation is likely to occur in the electrode mixture slurry, which in turn is likely to cause gelation of the electrode mixture slurry. This gelation problem is particularly likely to occur when the surface area of the solids relative to the content of the binder and dispersant contained in the electrode mixture slurry is large.

[0006] Therefore, an object of the present disclosure is to provide an electrode mixture slurry for solid-state batteries that is inhibited from gelling. [Means for solving the problem]

[0007] The present disclosure achieves the above object by the following means.

[0008] <Aspect 1> An electrode mixture slurry for a solid-state battery, the electrode mixture slurry contains an electrode active material, a solid electrolyte, a conductive additive, a binder, and a dispersant; A1 represented by the following formula 1 is 700 or more: A1=B / C1…Formula 1 B: m of the electrode active material, the solid electrolyte, and the conductive additive contained in 1 g of the electrode mixture slurry 2 Total surface area in units C1: The content ratio of the binder in parts by mass relative to 1 part by mass of the electrode mixture slurry A2 represented by the following formula 2 is 2000 or more: A2=B / C2…Formula 2 B: m of the electrode active material, the solid electrolyte, and the conductive additive contained in 1 g of the electrode mixture slurry 2 Total surface area in units C2: Content ratio of the dispersant in parts by mass relative to 1 part by mass of the electrode mixture slurry The storage modulus of the electrode mixture slurry is smaller than the loss modulus of the electrode mixture slurry over the entire shear strain range of 0.01% to 1000%. Electrode mixture slurry for solid-state batteries. <Aspect 2> 2. The electrode mixture slurry according to aspect 1, wherein the electrode active material is a negative electrode active material. <Aspect 3> A method for producing an electrode mixture slurry according to aspect 1 or 2, comprising the steps of: providing a preliminary electrode mixture slurry containing the electrode active material, the solid electrolyte, the conductive additive, the binder, and the dispersant; and The above preliminary electrode mixture slurry was added with 3.0 × 10 6 Applying dispersion energy of 1 J / L or less to the preliminary electrode mixture slurry to agitate the preliminary electrode mixture slurry, thereby preparing the electrode mixture slurry. [Effects of the Invention]

[0009] The electrode mixture slurry for a solid-state battery according to the present disclosure can suppress gelation. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows the storage modulus and loss modulus of the electrode mixture slurry S1 of Example 1 in the shear strain range of 0.01% to 1000%. [Figure 2] FIG. 2 shows the storage modulus and loss modulus of the electrode mixture slurry s1 of Comparative Example 1 in the shear strain range of 0.01% to 1000%. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present disclosure. In addition, in the description of the drawings, the same elements are given the same reference numerals, and duplicated descriptions will be omitted.

[0012] In the present disclosure, a "composite" refers to a composition that can constitute an electrode active material layer either as is or by further containing other components. Also, in the present disclosure, a "composite slurry" refers to a slurry that contains a "composite" and a dispersion medium and that can be applied and dried to form an electrode active material layer.

[0013] In the context of the present disclosure, a "solid-state battery" refers to a battery that uses at least a solid electrolyte as the electrolyte, and therefore a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as the electrolyte. Alternatively, the solid-state battery of the present disclosure may be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as the electrolyte.

[0014] Electrode mixture slurry The electrode mixture slurry for a solid-state battery according to the present disclosure is the electrode mixture slurry contains an electrode active material, a solid electrolyte, a conductive additive, a binder, and a dispersant; A1 represented by the following formula 1 is 700 or more: A1=B / C1…Formula 1 B: m of the electrode active material, the solid electrolyte, and the conductive additive contained in 1 g of the electrode mixture slurry 2 Total surface area in units C1: The content ratio of the binder in parts by mass relative to 1 part by mass of the electrode mixture slurry A2 represented by the following formula 2 is 2000 or more: A2=B / C2…Formula 2 B: m of the electrode active material, the solid electrolyte, and the conductive additive contained in 1 g of the electrode mixture slurry 2 Total surface area in units C2: Content ratio of the dispersant in parts by mass relative to 1 part by mass of the electrode mixture slurry The storage modulus of the electrode mixture slurry is smaller than the loss modulus of the electrode mixture slurry over the entire range of shear strain from 0.01% to 1000%.

[0015] The electrode mixture slurry for a solid-state battery according to the present disclosure can suppress gelation.

[0016] Without being limited by theory, it is presumed that for electrode mixture slurries prone to flocculation, i.e., electrode mixture slurries in which the ratio of the surface area of solid components such as electrode active material to that of binder and dispersant is large, specifically, electrode mixture slurries in which A1 defined as above is 700 or more and A2 defined as above is 2000 or more, if the storage modulus of the electrode mixture slurry is smaller than the loss modulus throughout the entire range of shear strain 0.01% to 1000%, the electrode mixture slurry will maintain liquid-like properties even when subjected to shear force due to transportation, etc., thereby suppressing gelation of the electrode mixture slurry. On the other hand, if the storage modulus of the electrode mixture slurry is smaller than the loss modulus over at least a portion of the range of shear strain 0.01% to 1000%, the electrode mixture slurry will exhibit solid-like properties depending on the force applied to the electrode mixture slurry when subjected to shear force due to transportation, etc., thereby causing gelation of the electrode mixture slurry.

[0017] <Configuration of electrode mixture slurry for solid state battery> The electrode mixture slurry for a solid-state battery according to the present disclosure includes an electrode active material, a solid electrolyte, a conductive additive, a binder, and a dispersant. The electrode mixture slurry may also include, but is not limited to, a dispersion medium.

[0018] In the present disclosure, the storage modulus of the electrode mixture slurry is smaller than the loss modulus of the electrode mixture slurry over the entire range of shear strain from 0.01% to 1000%.

[0019] The storage modulus and loss modulus of the electrode mixture slurry can be measured by changing the shear strain in the range of 0.01% to 1000% at a constant frequency using a rheometer, such as Anton Paar's MCR302.

[0020] The storage modulus of the electrode mixture slurry is not particularly limited as long as it is smaller than the loss modulus of the electrode mixture slurry. The storage modulus of the electrode mixture slurry over the entire range of shear strain 0.01% to 1000% is not particularly limited, but may be 0.1 MPa or more, 0.5 MPa or more, 1.0 MPa or more, 1.5 MPa or more, or 2.0 MPa or more, or 10 MPa or less, 5.0 MPa or less, 4.0 MPa, 3.5 MPa, 3.0 MPa, 2.5 MPa or less, or 2.0 MPa or less.

[0021] The loss modulus of the electrode mixture slurry is not particularly limited as long as it is greater than the storage modulus of the electrode mixture slurry. The loss modulus of the electrode mixture slurry over the entire shear strain range of 0.01% to 1000% is not particularly limited, but may be 0.1 MPa or more, 0.5 MPa or more, 1.0 MPa or more, 1.5 MPa or more, or 2.0 MPa or more, or 10 MPa or less, 5.0 MPa or less, 4.0 MPa, 3.5 MPa, 3.0 MPa, 2.5 MPa or less, or 2.0 MPa or less.

[0022] The ratio of the loss modulus to the storage modulus of the electrode mixture slurry ("loss modulus" / "storage modulus") throughout the shear strain range of 0.01% to 1000%, i.e., the loss tangent (tan δ), may be 1.0 or more, 1.2 or more, 1.4 or more, 1.6 or more, 1.8 or more, or 2.0 or more, or may be 50 or less, 40 or less, 30 or less, or 20 or less.

[0023] The difference between the loss modulus and storage modulus of the electrode mixture slurry throughout the entire shear strain range of 0.01% to 1000% ("loss modulus" - "storage modulus") is not particularly limited, but may be 0.01 MPa or more, 0.1 MPa or more, 0.5 MPa or more, 1.0 MPa or more, or 10 MPa or less, 5.0 MPa or less, 2.0 MPa or less, or 1.0 MPa or less.

[0024] The ratio of the mass of the solid content to the mass of the electrode mixture slurry of the present disclosure, i.e., the solid content concentration of the electrode mixture slurry, is not particularly limited, but may be 40 mass% or more, 50 mass% or more, 60 mass% or more, 70 mass% or more, or 80 mass% or more, or may be 100 mass% or less, 90 mass% or less, or 80 mass% or less.

[0025] <Electrode active material> The electrode active material may be a positive electrode active material or a negative electrode active material, and is not particularly limited, but is preferably a negative electrode active material.

[0026] (Cathode active material) The material of the positive electrode active material is not particularly limited as long as it can absorb and release lithium ions. Examples of the positive electrode active material include lithium cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), lithium manganese oxide (LiMnO), and nickel-cobalt-manganese oxide (NCM:LiCO 1 / 3 Ni 1 / 3 Mn 1 / 3 O2), lithium nickel-cobalt-aluminate (LiNi 0.8 (CoAl) 0.2 O2), Li 1+x Mn 2-x-y M y The material may be, but is not limited to, a different element-substituted Li-Mn spinel having a composition represented by O4 (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn).

[0027] The positive electrode active material may have a coating layer, although it is not particularly limited. The coating layer is a layer containing a substance that has lithium ion conductivity, low reactivity with the positive electrode active material and the solid electrolyte, and can maintain the shape of the coating layer without flowing even when in contact with the active material and the solid electrolyte. Specific examples of materials that constitute the coating layer include LiNbO3 and Li4Ti5O 12 , Li3PO4, Li-Ti-Al-F based materials, etc., but are not limited to these.

[0028] The shape of the positive electrode active material is not particularly limited as long as it is a general shape for a positive electrode active material of a solid-state battery. The positive electrode active material may be, for example, in the form of particles. The positive electrode active material may be primary particles or secondary particles formed by agglomeration of a plurality of primary particles. The specific surface area of the positive electrode active material is not particularly limited, but is preferably 0.5 m 2 / g or more, 1.0m 2 / g or more, 2.0m 2 / g or more, 3.0m 2 / g or more, or 3.5m 2 / g or more, and 2 / g or less, 8.0m 2 / g or less, 6.0m 2 / g or less, or 4.0m 2 The specific surface area of the positive electrode active material can be measured by the BET method using nitrogen as an adsorbate.

[0029] (Negative electrode active material) As the negative electrode active material, various substances can be used that have a potential (charge / discharge potential) for absorbing and releasing lithium ions that is lower than that of the positive electrode active material of the present disclosure. The material for the negative electrode active material is not particularly limited, and may be metallic lithium or a material capable of absorbing and releasing metal ions such as lithium ions. Examples of materials capable of absorbing and releasing metal ions such as lithium ions include alloy-based negative electrode active materials, carbon materials, and lithium titanate (Li4Ti5O 12 ) and the like can be mentioned, but are not limited to these.

[0030] The alloy-based negative electrode active material is not particularly limited, and examples thereof include Si alloy-based negative electrode active materials and Sn alloy-based negative electrode active materials. Examples of Si alloy-based negative electrode active materials include silicon, silicon oxide, silicon carbide, silicon nitride, and solid solutions thereof. The Si alloy-based negative electrode active material may contain metal elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, and Ti. Examples of Sn alloy-based negative electrode active materials include tin, tin oxide, tin nitride, and solid solutions thereof. The Sn alloy-based negative electrode active material may contain metal elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, and Si.

[0031] The carbon material is not particularly limited, and examples thereof include hard carbon, soft carbon, graphite, and the like.

[0032] The shape of the negative electrode active material is not particularly limited as long as it is a general shape for a negative electrode active material of a solid-state battery. The negative electrode active material may be, for example, in the form of particles. The negative electrode active material may be in the form of primary particles or secondary particles formed by aggregation of a plurality of primary particles. The specific surface area of the negative electrode active material is not particularly limited, but is preferably 0.5 m 2 / g or more, 1.0m 2 / g or more, 2.0m 2 / g or more, 3.0m 2 / g or more, or 3.5m 2 / g or more, and 2 / g or less, 8.0m 2 / g or less, 6.0m 2 / g or less, or 4.0m 2 The specific surface area of the negative electrode active material can be measured by the BET method using nitrogen as an adsorbate.

[0033] <Solid electrolyte> The material of the solid electrolyte is not particularly limited, and may be, for example, a sulfide solid electrolyte, an oxide solid electrolyte, or a polymer electrolyte.

[0034] Examples of sulfide solid electrolytes include, but are not limited to, sulfide-based amorphous solid electrolytes, sulfide-based crystalline solid electrolytes, and argyrodite-type solid electrolytes. Specific examples of sulfide solid electrolytes include Li2S-P2S5-based (Li7P3S 11 , Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2(Li 13 GeP3S 16 , Li 10 GeP2S 12 ), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x etc.; or combinations thereof, but are not limited to these.

[0035] An example of an oxide solid electrolyte is Li7La3Zr2O 12 , Li 7-x La3Zr 1-x Nb x O 12 , Li 7-3x La3Zr2Al x O 12 , Li 3x La 2 / 3-x TiO3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+x Al x Ge 2-x (PO4)3, Li3PO4, or Li 3+x PO 4-x N x (LiPON), etc., but are not limited to these.

[0036] The sulfide solid electrolyte and the oxide solid electrolyte may be glass or crystallized glass (glass ceramics).

[0037] Examples of polymer electrolytes include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

[0038] The shape of the solid electrolyte is not particularly limited as long as it is a general shape for a solid electrolyte in a solid-state battery. The solid electrolyte may be, for example, in the form of particles. The solid electrolyte may be primary particles or secondary particles formed by agglomeration of a plurality of primary particles. The specific surface area of the solid electrolyte is not particularly limited, but is preferably 1.0 m 2 / g or more, 2.0m 2 / g or more, 4.0m 2 / g or more, 6.0m 2 / g or more, or 8.0m 2 / g or more, and 2 / g or less, 13m 2 / g or less, 11m 2 / g or less, or 9.0m 2 The specific surface area of the solid electrolyte can be measured by the BET method using nitrogen as an adsorbate.

[0039] <Conductive additive> The conductive additive is not particularly limited. Examples of the conductive additive include vapor grown carbon fiber (VGCF), acetylene black (AB), ketjen black (KB), carbon nanotubes (CNT), carbon nanofibers (CNF), conductive carbon, etc., but are not limited to these. The conductive additive is not particularly limited, and one type may be used alone, or two or more types may be used in combination.

[0040] The conductive additive may be, for example, particulate or fibrous, and its size is not particularly limited. The specific surface area of the conductive additive is not particularly limited, but is preferably 4.0 m 2 / g or more, 6.0m 2 / g or more, 8.0m 2 / g or more, 10m 2 / g or more, or 12m 2 / g or more, 2 / g or less, 18m 2 / g or less, 16m2 / g or less, or 14m 2 The specific surface area of the conductive additive can be measured by the BET method using nitrogen as an adsorbate.

[0041] <Binder> The binder is not particularly limited. The binder may be, for example, polyvinylidene fluoride (PVdF), butadiene rubber (BR), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), or other materials, but is not limited to these. The binder is not particularly limited, and one type may be used alone, or two or more types may be used in combination.

[0042] In the electrode mixture slurry for a solid state battery according to the present disclosure, A1, represented by the following formula 1, is 700 or more. A1=B / C1…Formula 1 B: m of electrode active material, solid electrolyte, and conductive additive contained in 1 g of electrode mixture slurry 2 Total surface area in units C1: Content ratio of binder in parts by mass per part by mass of electrode mixture slurry

[0043] The larger the A1 of the electrode mixture slurry, the larger the total surface area of the electrode active material, solid electrolyte, and conductive additive contained in the electrode mixture slurry, or the smaller the content of binder contained in the electrode mixture, and the binder does not stabilize the dispersion state of the electrode active material, solid electrolyte, and conductive additive, which makes flocculation more likely to occur in the electrode mixture slurry. The A1 of the electrode mixture slurry of the present disclosure is not particularly limited, and may be 700 or more, 720 or more, 740 or more, 760 or more, or 780 or more, or may be 1000 or less, 950 or less, 900 or less, or 850 or less.

[0044] B is the m of electrode active material, solid electrolyte, and conductive additive contained in 1 g of electrode mixture slurry. 2When two or more electrode active materials are used, the surface area of the electrode active materials refers to the total amount. The same applies to the solid electrolyte and the conductive additive. The surface area is calculated by dividing the specific surface area (m 2 The specific surface area can be determined by multiplying the specific surface area (g / g) by the content (g) of each component. The specific surface area can be measured by the BET method using nitrogen as an adsorbate. B of the electrode mixture slurry of the present disclosure is not particularly limited, but may be 1.0 or more, 1.5 or more, 2.0 or more, 2.5 or more, or 3.0 or more, or may be 10 or less, 8.0 or less, 6.0 or less, or 4.0 or less.

[0045] C1 is the binder content in parts by mass per part by mass of the electrode mixture slurry. When two or more binders are included, the binder content refers to the total amount. C1 of the electrode mixture slurry of the present disclosure is not particularly limited, but may be 0.001 or more, 0.002 or more, 0.003 or more, or 0.004 or more, or may be 0.01 or less, 0.008 or less, 0.006 or less, or 0.005 or less.

[0046] <Dispersant> The dispersant is not particularly limited. For example, a high molecular weight alkylol amino amide compound can be used as the dispersant, but this is not limited to this. The dispersant is not particularly limited, and one type may be used alone, or two or more types may be used in combination.

[0047] In the electrode mixture slurry for a solid state battery according to the present disclosure, A2, represented by the following formula 2, is 2000 or more. A2=B / C2…Formula 2 B: m of electrode active material, solid electrolyte, and conductive additive contained in 1 g of electrode mixture slurry 2 Total surface area in units C2: Content ratio of dispersant in parts by mass per part by mass of electrode mixture slurry

[0048] The larger the A2 of the electrode mixture slurry, the larger the total surface area of the electrode active material, solid electrolyte, and conductive additive contained in the electrode mixture slurry, or the smaller the content of dispersant contained in the electrode mixture, and the dispersant does not stabilize the dispersion state of the electrode active material, solid electrolyte, and conductive additive, which makes flocculation more likely to occur in the electrode mixture slurry. The A2 of the electrode mixture slurry of the present disclosure is not particularly limited, and may be 2000 or more, 2050 or more, 2100 or more, 2150 or more, or 2200 or more, or may be 3000 or less, 2800 or less, 2600 or less, or 2400 or less.

[0049] C2 is the content ratio of the dispersant in parts by mass per part by mass of the electrode mixture slurry. When two or more dispersants are included, the content of the dispersants refers to the total amount. C2 of the electrode mixture slurry of the present disclosure is not particularly limited, but may be 0.0001 or more, 0.0005 or more, 0.0008 or more, 0.0011 or more, or 0.0014 or more, or may be 0.0040 or less, 0.0030 or less, 0.0020 or less, or 0.0015 or less.

[0050] For B, please refer to the description of "<Binder>" above.

[0051] <Dispersion medium> The dispersion medium is not particularly limited. Examples of the dispersion medium include, but are not limited to, tetralin (1,2,3,4-tetrahydronaphthalene), anisole, xylene, octane, hexane, decalin, butyl acetate, ethyl propionate, tripropylamine, N-methyl-2-pyrrolidone (NMP), and water. The dispersion medium is not particularly limited, and one type may be used alone, or two or more types may be used in combination.

[0052] The values of A1 and A2 of the electrode mixture slurry can be determined as follows. The electrode mixture slurry is separated into solid components, namely, active material, solid electrolyte, and conductive additive, and solution components, namely, binder, dispersant, and solvent, using a centrifuge. The amount and type of each solid component are identified using ICP. Next, the content of each solution component is determined using TG-DTA, and the material type of each component is identified using FT-IR. This allows the proportions of electrode active material, solid electrolyte, conductive additive, binder, and dispersant contained per 1 g of the electrode mixture slurry to be calculated. m 2 Calculate B, C1, and C2 by calculating the total surface area per unit. 1、 A2 is calculated. Here, the value of the specific surface area of each substance may be a value listed in the literature, or if the literature value is not appropriate, the specific surface area confirmed by the BET method may be used. Furthermore, whether the storage modulus of the electrode mixture slurry is smaller than the loss modulus of the electrode mixture slurry throughout the entire range of shear strain from 0.01% to 1000% can be determined by measuring the electrode mixture slurry with a rheometer at a frequency of 1 Hz in the strain range of 0.01% to 1000% and confirming the storage modulus G' and loss modulus G'' at that time.

[0053] <<Method for producing electrode mixture slurry>> The electrode mixture slurry for a solid battery according to the present disclosure can be produced by a production method including the following steps. Providing a preliminary electrode mixture slurry containing an electrode active material, a solid electrolyte, a conductive additive, a binder, and a dispersant; and 3.0 x 10 for the preliminary electrode mixture slurry 6 A dispersion energy of J / L or less is applied to the preliminary electrode mixture slurry to agitate the preliminary electrode mixture slurry, thereby preparing the electrode mixture slurry.

[0054] According to the method for producing an electrode mixture slurry of the present disclosure, it is possible to produce an electrode mixture slurry of the present disclosure in which gelation is suppressed.

[0055] Without being limited by theory, the dispersion energy when producing the electrode mixture slurry is set to 3.0 × 10 6 By setting the shear strain at J / L or less, over-dispersion of the electrode mixture slurry is suppressed, and as a result, an electrode mixture slurry of the present disclosure in which the storage modulus of the electrode mixture slurry is smaller than the loss modulus over the entire shear strain range of 0.01% to 1000%, i.e., in which gelation is suppressed, can be produced.

[0056] <Provision of spare electrode mixture slurry> The method for providing the preliminary electrode mixture slurry is not particularly limited, and the preliminary electrode mixture slurry may be prepared by introducing the electrode active material, the solid electrolyte, the conductive additive, the binder, and the dispersion medium into a predetermined container and mixing them, or by obtaining a mixture of the electrode active material, the solid electrolyte, the conductive additive, the binder, and the dispersion medium.

[0057] For the electrode active material, solid electrolyte, conductive additive, binder, and dispersion medium contained in the preliminary electrode mixture slurry, reference can be made to the description above in "<Configuration of electrode mixture slurry for solid state battery>".

[0058] <Application of Dispersion Energy to Preliminary Electrode Mixture Slurry> The dispersion energy can be applied using, for example, an ultrasonic homogenizer (US600AT manufactured by Nippon Seiki Co., Ltd.), but is not limited to this. The dispersion energy can be calculated from the power and time when the dispersion energy is applied. When an ultrasonic homogenizer (US600AT manufactured by Nippon Seiki Co., Ltd.) is used, the power applied to the preliminary electrode mixture slurry is not particularly limited, but may be 150 W or more, 200 W or more, or 250 W or more, or 650 W or less, 600 W or less, or 550 W or less.

[0059] The dispersion energy applied to the preliminary electrode mixture slurry is not particularly limited, but from the viewpoint of dispersion, it is 1.0 × 10 5 J / L or above, 5.0×10 5 J / L or above, 1.0×10 6J / L or more, or 2.0 x 10 6 J / L or more, and from the viewpoint of suppressing overdispersion, 3.0 × 10 6 J / L or less, 2.8×10 6 J / L or less, 2.6×10 6 It may be J / L or less.

[0060] The method for stirring the preliminary electrode mixture slurry is not particularly limited, and any general method capable of stirring the electrode mixture slurry can be employed.

[0061] 《Solid-state battery》 A solid-state battery may include an electrode active material layer formed from the electrode mixture slurry of the present disclosure.

[0062] The electrode active material layer can be produced by a known method using the electrode mixture slurry of the present disclosure. For example, the electrode mixture slurry containing various components can be applied to a substrate and dried to form an electrode active material layer.

[0063] The method for forming the solid-state battery is not particularly limited, and known methods can be used. For example, the method for forming the solid-state battery can be, but is not limited to, arranging a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer in this order, laminating and sealing them to form a solid-state battery. The solid-state battery may be constrained by an external pressure of, for example, 5 MPa, but is not particularly limited to this. [Example]

[0064] The present disclosure will be described in more detail with reference to the following examples, but the scope of the present disclosure is not limited to these examples.

[0065] Example 1 <Preparation of electrode mixture slurry S1> Li4Ti5O as a negative electrode active material 12 Particles (specific surface area 3.8m 2 / g) (48.57 mass%) and Li2S-P2S5-based glass ceramics (specific surface area 8.7 m) as a solid electrolyte. 2 / g) (16.32 mass%) and conductive carbon (13m 2 / g) (0.54 mass%), a styrene butadiene rubber (SBR) binder (0.42 mass%) as a binder, a high-molecular-weight alkylol aminoamide compound (0.15 mass%) as a dispersant, and an appropriate amount of tetralin (34.00 mass%) as a dispersion medium were mixed, and the mixture was homogenized with an ultrasonic homogenizer (US600AT manufactured by Nippon Seiki Co., Ltd.) at a dispersion energy of 2.5 × 10 6 The electrode mixture slurry S1 was prepared by applying a J / L voltage and stirring. The dispersion energy was calculated from the output and time of the ultrasonic homogenizer. The electrode mixture slurry S1 did not gel even when subjected to vibrations during transportation.

[0066] <A1 of electrode mixture slurry S1> The electrode active material, solid electrolyte, and conductive additive contained in 1 g of electrode mixture slurry 2 The surface area of the electrode active material is 1.85 m 2 and the surface area of the solid electrolyte is 1.42 m 2 and the surface area of the conductive additive is 0.07 m 2 Therefore, the m of the electrode active material, solid electrolyte, and conductive additive contained in the electrode mixture slurry S1 2 The total surface area of the unit is 3.34 m 2 In addition, since the binder was contained in an amount of 0.0042 parts by mass relative to 1 part by mass of the electrode mixture slurry, A1 was 794, which satisfied the requirement of A1 being 700 or more.

[0067] <A2 of electrode mixture slurry S1> As described above, the electrode active material, solid electrolyte, and conductive additive contained in the electrode mixture slurry S1 2 The total surface area of the unit is 3.34 m 2 In addition, since the dispersant was contained in an amount of 0.0015 parts by mass relative to 1 part by mass of the electrode mixture slurry, A2 was 2224, which satisfied the requirement of 2200 or more.

[0068] <Measurement of storage modulus and loss modulus of electrode mixture slurry S1> A predetermined amount of electrode mixture slurry S1 was introduced into a rheometer (Anton Paar MCR302), and the storage modulus and loss modulus were measured while the shear strain was varied in the range of 0.01% to 1000% at a constant frequency. Figure 1 shows the storage modulus (G'), loss modulus (G''), and loss tangent (tanδ) of electrode mixture slurry S1 in the shear strain range of 0.01% to 1000%.

[0069] Comparative Example 1 <Preparation of electrode mixture slurry s1> Dispersion energy 3.5×10 6 Except for using J / L, electrode mixture slurry s1 was prepared in the same manner as in Example 1. Note that the composition of electrode mixture slurry s1 was the same as that of electrode mixture slurry S1, and therefore A1 and A2 of electrode mixture slurry s1 were the same as A1 and A2 of electrode mixture slurry S1. When the electrode mixture slurry s1 was subjected to vibrations due to transportation or the like, gelation occurred.

[0070] <Measurement of storage modulus and loss modulus of electrode mixture slurry s1> The storage modulus and loss modulus of the electrode mixture slurry s1 were measured in the same manner as in Example 1. Fig. 2 shows the storage modulus (G'), loss modulus (G''), and loss tangent (tanδ) of the electrode mixture slurry s1 in the shear strain range of 0.01% to 1000%.

[0071] [Table 1]

[0072] The electrode mixture slurries of Example 1 and Comparative Example 2 were prepared with solid compositions that tended to cause flocculation, i.e., solid compositions in which A1 was 700 or more and A2 was 2000 or more. Despite having the same composition, the electrode mixture slurry S1 in which the storage modulus was smaller than the loss modulus over the entire shear strain range of 0.01% to 1000% did not gel, whereas the electrode mixture slurry s1 in which the storage modulus was smaller than the loss modulus over at least a portion of the shear strain range of 0.01% to 1000% did gel.

[0073] In addition, the dispersion energy when producing the electrode mixture slurry was 2.5 × 10 6 When J / L was applied, the electrode mixture slurry S1 had a storage modulus smaller than the loss modulus over the entire shear strain range of 0.01% to 1000%. However, when the dispersion energy was 3.5 × 10 6 When J / L was applied, an electrode mixture slurry s1 was obtained in which the storage modulus was smaller than the loss modulus in at least a part of the shear strain range of 0.01% to 1000%.

[0074] For electrode mixture slurries prone to flocculation, i.e., electrode mixture slurries in which A1 is 700 or more and A2 is 2000 or more, if the storage modulus of the electrode mixture slurry is smaller than the loss modulus throughout the entire range of shear strain 0.01% to 1000%, the electrode mixture slurry maintains liquid-like properties even when shear force due to transportation, etc. is applied to the electrode mixture slurry, thereby presumably suppressing gelation of the electrode mixture slurry. On the other hand, if the storage modulus of the electrode mixture slurry is smaller than the loss modulus over at least a portion of the range of shear strain 0.01% to 1000%, the electrode mixture slurry exhibits solid-like properties when shear force due to transportation, etc. is applied to the electrode mixture slurry, thereby presumably causing gelation of the electrode mixture slurry.

[0075] In addition, the dispersion energy when producing the electrode mixture slurry is 3.0 × 10 6By setting the shear strain at 0.01% to 1000%, it is presumed that the over-dispersion of the electrode mixture slurry is suppressed, and as a result, an electrode mixture slurry is obtained in which the storage modulus of the electrode mixture slurry is smaller than the loss modulus over the entire range of shear strain from 0.01% to 1000%.

[0076] While preferred embodiments of the electrode mix slurry for solid state batteries and the method for manufacturing the electrode mix slurry of the present disclosure have been described, those skilled in the art will recognize that modifications are possible without departing from the scope of the claims.

Claims

1. An electrode mixture slurry for a solid-state battery, the electrode mixture slurry contains an electrode active material, a solid electrolyte, a conductive additive, a binder, and a dispersant, A represented by the following formula 1 １ is greater than or equal to 700 and: A １ =B / C １ …Formula 1 B: m of the electrode active material, the solid electrolyte, and the conductive additive contained in 1 g of the electrode mixture slurry ２ Total surface area in units C １ : Content ratio of the binder in parts by mass relative to 1 part by mass of the electrode mixture slurry A represented by the following formula 2 ２ is greater than or equal to 2000 and: A ２ =B / C ２ ...Formula 2 B: m of the electrode active material, the solid electrolyte, and the conductive additive contained in 1 g of the electrode mixture slurry ２ Total surface area in units C ２ : Content ratio of the dispersant in parts by mass relative to 1 part by mass of the electrode mixture slurry The storage modulus of the electrode mixture slurry is smaller than the loss modulus of the electrode mixture slurry over the entire shear strain range of 0.01% to 1000%. Electrode mixture slurry for solid-state batteries.

2. The electrode mixture slurry according to claim 1 , wherein the electrode active material is a negative electrode active material.

3. 3. A method for producing an electrode mixture slurry according to claim 1, comprising the following steps: Providing a preliminary electrode mixture slurry containing the electrode active material, the solid electrolyte, the conductive additive, the binder, and the dispersant; and The preliminary electrode mixture slurry was added with 3.0 × 10 ６ and applying dispersion energy of 1 / 10 or less to the preliminary electrode mixture slurry to agitate the preliminary electrode mixture slurry, thereby preparing the electrode mixture slurry.

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