Electrode composite slurry for solid-state battery and method for producing electrode composite slurry

Abstract

To provide an electrode composite slurry for a solid-state battery capable of obtaining an electrode active material layer that reduces battery resistance, and a method for producing the same.SOLUTION: An electrode composite slurry includes: an electrode active material; a solid electrolyte; and dispersion media. A particle diameter of the electrode composite slurry measured by a grind gauge method is 60 μ m or less. A method for producing the electrode composite slurry includes the steps of: (i) preparing the electrode composite slurry by applying dispersion energy of 1.0×106 J / L or more to a preliminary electrode composite slurry and stirring the preliminary electrode composite slurry, and / or (ii) stirring the preliminary electrode composite slurry until a particle size measured by a grind gauge method becomes 0.75 times or less relative to a particle size measured by the grind gauge method when the preliminary electrode composite slurry is stirred by applying a dispersion energy of 5.0×105 J / L to prepare the electrode composite slurry.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an electrode composite slurry for a solid-state battery and a method for manufacturing the electrode composite slurry.

Background Art

[0002] An electrode active material layer and a solid electrolyte layer used in a solid-state battery are generally formed by coating an electrode composite slurry or a solid electrolyte composite slurry containing an electrode active material, a solid electrolyte, and a dispersion medium on the surface of a substrate, drying, and pressing if necessary. The following binder composition and a method for manufacturing an all-solid-state battery using the solid electrolyte composite slurry containing the binder composition are known.

[0003] For example, Patent Document 1 discloses a composition containing a dispersion medium and a binder particle group. The binder particle group is dispersed in the dispersion medium. The binder particle group contains a polymer material. The polymer material contains a structural unit derived from vinylidene fluoride. The binder particle group has a particle size distribution based on the number, and the particle size distribution satisfies the following formulas (1) to (3): 0.19 ≦ X ≦ 0.26 (1) 0.69 ≦ Y ≦ 0.76 (2) 0 ≦ Z ≦ 0.05 (3) A binder composition is disclosed that satisfies the conditions, where in the above formula (1), X represents the frequency of particles having a particle diameter of 40 μm or less, in the above formula (2), Y represents the frequency of particles having a particle diameter exceeding 40 μm and being 110 μm or less, and in the above formula (3), Z represents the frequency of particles having a particle diameter exceeding 110 μm and being 250 μm or less. According to the binder composition of Patent Document 1, in a slurry composition containing a sulfide solid electrolyte, it is said that aggregates are difficult to form. Further, Patent Document 1 discloses preparing a slurry composition by mixing the binder composition and a sulfide solid electrolyte, crushing the aggregates contained in the slurry composition, and after crushing the aggregates, applying the slurry composition to the surface of a substrate and drying it to form a separator, and manufacturing an all-solid-state battery including the separator. According to the manufacturing method of the all-solid-state battery of Patent Document 1, it is expected that by reducing aggregates, the variation in the thickness of the separator becomes small, and the discharge resistance of the all-solid-state battery is reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the manufacturing method of the all-solid-state battery of Patent Document 1, as described above, by reducing aggregates in the slurry for forming the solid electrolyte layer, the variation in the thickness of the obtained separator (solid electrolyte layer) becomes small, and thereby it is expected that the discharge resistance of the all-solid-state battery is reduced.

[0006] In contrast, when obtaining an electrode active material layer using an electrode composite material slurry, the inventors of the present invention have found that even when no aggregation occurs as observed as the variation in the thickness of the obtained electrode active material layer, the battery resistance increases due to slight aggregation.

[0007] Therefore, an object of the present disclosure is to provide an electrode composite material slurry for a solid battery and a method for manufacturing the electrode composite material slurry, which can obtain an electrode active material layer that reduces battery resistance.

Means for Solving the Problems

[0008] The present disclosure achieves the above object by the following means.

[0009] <Aspect 1> An electrode composite material slurry for a solid battery, wherein the electrode composite material slurry contains an electrode active material, a solid electrolyte, and a dispersion medium, and the particle diameter of the electrode composite material slurry measured by the particle gauge method is 60 μm or less, electrode composite material slurry. <Aspect 2> The electrode composite material slurry according to Aspect 1, wherein the electrode composite material slurry contains a rubber-based binder. <Aspect 3> The electrode composite material slurry according to Aspect 1 or 2, wherein the electrode composite material slurry contains a negative electrode active material. <Aspect 4> A method for manufacturing the electrode composite material slurry according to any one of Aspects 1 to 3, including the following steps: providing a preliminary electrode composite material slurry containing an electrode active material, a solid electrolyte, and a dispersion medium, and (i) applying a dispersion energy of 1.0×10 6 J / L or more to the preliminary electrode composite material slurry to stir the preliminary electrode composite material slurry to prepare the electrode composite material slurry, and / or (ii) stirring the preliminary electrode composite material slurry until the particle diameter measured by the particle gauge method becomes 0.75 times or less of the particle diameter measured by the particle gauge method when the preliminary electrode composite material slurry is stirred by applying a dispersion energy of 5.0×10 5 J / L to prepare the electrode composite material slurry. <Aspect 5> An electrode active material layer for a solid battery, wherein the maximum particle diameters of the electrode active material and the solid electrolyte measured from the SEM image of the cross-section of the electrode active material layer are 60 μm or less. Electrode active material layer.

Advantages of the Invention

[0010] According to the electrode composite material slurry and the method for manufacturing the electrode composite material slurry of the present disclosure, an electrode active material layer capable of reducing battery resistance can be obtained.

Brief Description of the Drawings

[0011]

Figure 1

Modes for Carrying Out the Invention

[0012] 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.

[0013] Regarding the present disclosure, "composite material" means a composition that can form an electrode active material layer or a solid electrolyte layer as it is or by further containing other components. Also, regarding the present disclosure, "composite material slurry" means a slurry that contains a dispersion medium in addition to the "composite material" and can form an electrode active material layer or a solid electrolyte layer by coating and drying.

[0014] Regarding the present disclosure, "solid battery" means a battery that uses at least a solid electrolyte as an electrolyte. Therefore, the solid battery may use a combination of a solid electrolyte and a liquid electrolyte as an electrolyte. Also, the solid battery may be an all-solid battery, that is, a battery that uses only a solid electrolyte as an electrolyte.

[0015] 《Electrode Composite Material Slurry for Solid Batteries》 The electrode composite slurry for a solid-state battery of the present disclosure The electrode composite slurry contains an electrode active material, a solid electrolyte, and a dispersion medium, and the particle diameter of the electrode composite slurry measured by the particle gauge method is 60 μm or less.

[0016] According to the electrode composite slurry of the present disclosure, an electrode active material layer that reduces battery resistance can be obtained.

[0017] Generally, the particle diameter measured by the particle gauge method is known as an index for obtaining a coating film with a uniform appearance in a slurry containing pigments and the like. The present inventors have found that the particle diameter of the electrode composite slurry measured by the particle gauge method is related not only to the uniformity of the coating film but also to the battery resistance.

[0018] Specifically, for example, when the particle diameter of the electrode composite slurry measured by the particle gauge method is 60 μm, an electrode active material layer with a uniform appearance can be obtained, and the resistance of a solid-state battery including the electrode active material layer formed from this electrode composite slurry is sufficiently low. On the other hand, even when the particle diameter of the electrode composite slurry measured by the particle gauge method is 80 μm, an electrode active material layer with a uniform appearance can be obtained. However, it has become clear that the resistance of a solid-state battery including the electrode active material layer formed from this electrode composite slurry is high, and there is a performance difference due to the difference in the particle diameter measured by the particle gauge method, despite the electrode composite slurry having the same composition. Therefore, by setting the particle diameter of the electrode composite slurry measured by the particle gauge method to 60 μm or less, not only can an electrode active material layer with a uniform appearance be obtained, but also an electrode active material layer that reduces battery resistance can be obtained.

[0019] <Configuration of the Electrode Composite Slurry for a Solid-State Battery> The electrode composite slurry for a solid-state battery of the present disclosure contains an electrode active material, a solid electrolyte, and a dispersion medium. Optionally, it may further contain a binder and a conductive assistant. The above electrode composite slurry may additionally contain various additives.

[0020] The content of each of the electrode active material, solid electrolyte, dispersion medium, etc. in the above electrode composite slurry may be appropriately determined according to the target slurry characteristics and battery performance. For example, taking the total solid content of the electrode composite slurry as 100 parts by mass, the content of the electrode active material may be 40 parts by mass or more, 50 parts by mass or more, or 60 parts by mass or more, and may also be 99 parts by mass or less, or 90 parts by mass or less. Further, for example, the solid content concentration of the electrode composite slurry (total solid content / (total solid content + dispersion medium)) may be 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, or 75% by mass or more, and may also be 90% by mass or less, 85% by mass or less, or 80% by mass or less.

[0021] (Electrode active material) The electrode active material contained in the above electrode composite slurry may be a positive electrode active material or a negative electrode active material. The electrode composite slurry for the solid battery of the present disclosure is not particularly limited, but preferably contains a negative electrode active material.

[0022] (Negative electrode active material) As the negative electrode active material, various substances having a potential (charge-discharge potential) for occluding and releasing lithium ions that is lower than that of the positive electrode active material can be adopted. The material of the negative electrode active material is not particularly limited, and may be a material capable of occluding and releasing metal ions such as lithium ions. Examples of the material capable of occluding and releasing metal ions such as lithium ions include lithium titanate (Li 4 Ti 5 O 12 ), alloy-based negative electrode active materials, carbon materials, etc., but are not limited thereto.

[0023] The alloy-based negative electrode active material is not particularly limited, and examples thereof include a silicon alloy-based negative electrode active material and a tin alloy-based negative electrode active material. The silicon alloy-based negative electrode active material includes silicon, silicon oxide, silicon carbide, silicon nitride, or a solid solution thereof. Further, the silicon alloy-based negative electrode active material can contain metal elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, Ti, etc. The tin alloy-based negative electrode active material includes tin, tin oxide, tin nitride, or a solid solution thereof. Further, the Sn alloy-based negative electrode active material can contain metal elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, Si, etc.

[0024] The carbon material is not particularly limited, and examples thereof include hard carbon, soft carbon, graphite, etc.

[0025] The shape of the powder of the negative electrode active material is not particularly limited as long as it is a general shape as the negative electrode active material of a lithium ion battery. The negative electrode active material may be, for example, particulate. The negative electrode active material may be primary particles or secondary particles in which a plurality of primary particles are aggregated. The average particle diameter D of the negative electrode active material as a raw material 50 may be, for example, 1 nm or more, 5 nm or more, or 10 nm or more, and may also be 50 μm or less, or 30 μm or less. Note that the average particle diameter D 50 is the particle diameter (median diameter) at 50% of the integrated value in the volume-based particle size distribution determined by the laser diffraction / scattering method.

[0026] (Positive electrode active material) The material of the positive electrode active material is not particularly limited. Examples of the positive electrode active material include lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), lithium manganate (LiMn 2 O 4 ), lithium nickel cobalt manganate (NCM), LiCO 1 / 3 Ni 1 / 3 Mn 1 / 3 O 2, lithium nickel cobalt aluminum oxide (NCA; LiNi x Co y Al z O 2 ), Li 1+x Mn 2-x-y M y O 4 (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn), and may be, but is not limited to, a heterogeneous element-substituted Li-Mn spinel having such a composition.

[0027] The positive electrode active material is not particularly limited, but may have a coating layer. The coating layer is a layer containing a substance that has lithium ion conduction performance, low reactivity with the positive electrode active material and the solid electrolyte, and can maintain the form of a coating layer that does not flow even when in contact with the active material and the solid electrolyte. Specific examples of the material constituting the coating layer include LiNbO 3 In addition to 4 Ti 5 O 12 , Li 3 PO 4 and the like, but are not limited thereto.

[0028] The shape of the powder of the positive electrode active material is not particularly limited as long as it is a general shape as the positive electrode active material of a lithium ion battery. The positive electrode active material may be, for example, particulate. The positive electrode active material may be primary particles or secondary particles in which a plurality of primary particles are aggregated. The average particle diameter D 50 of the positive electrode active material as a raw material may be, for example, 1 nm or more, 5 nm or more, or 10 nm or more, and may also be 50 μm or less, or 30 μm or less. The average particle diameter D 50 is the particle diameter (median diameter) at 50% of the integrated value in the volume-based particle size distribution determined by the laser diffraction / scattering method.

[0029] (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.

[0030] Examples of sulfide solid electrolytes include, but are not limited to, sulfide-based amorphous solid electrolytes, sulfide-based crystalline solid electrolytes, or argyrodite-type solid electrolytes. Specific examples of sulfide solid electrolytes include Li 2 S-P 2 S 5 system (Li 7 P 3 S 11 , Li 3 PS 4 , Li 8 P 2 S 9 , etc.), Li 2 S-SiS 2 , LiI-Li 2 S-SiS 2 , LiI-Li 2 S-P 2 S 5 , LiI-LiBr-Li 2 S-P 2 S 5 , Li 2 S-P 2 S 5 -GeS 2 (Li 13 GeP 3 S 16 , Li 10 GeP 2 S 12 , etc.), LiI-Li 2 S-P 2 O 5 , LiI-Li 3 PO 4 -P 2 S 5 , Li 7-x PS 6-x Cl x , etc.; or combinations thereof can be mentioned, but are not limited thereto.

[0031] Examples of oxide solid electrolytes include Li 7 La 3 Zr 2 O 12 , Li 7-x La 3 Zr 1-x Nb x O 12 , Li 7-3x La3 Zr 2 Al x O 12 、Li 3x La 2 / 3-x TiO 3 、Li 1+x Al x Ti 2-x (PO 4 ) 3 、Li 1+x Al x Ge 2-x (PO 4 ) 3 、Li 3 PO 4 、 or Li 3+x PO 4-x N x (LiPON), etc. may be mentioned, but are not limited thereto.

[0032] The sulfide solid electrolyte and the oxide solid electrolyte may be glass or crystallized glass (glass ceramics).

[0033] Examples of the polymer electrolyte include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

[0034] (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), water, etc. The dispersion medium is not particularly limited, but only one kind may be used alone, or two or more kinds may be used in combination.

[0035] (Binder) The binder is not particularly limited, and for example, a rubber-based binder, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), etc. can be used. Examples of the rubber-based binder include, but are not limited to, butadiene rubber (BR), styrene-butadiene rubber (SBR), etc. The binder is not particularly limited, and only one type may be used alone, or two or more types may be used in combination. The electrode binder slurry for the solid battery of the present disclosure preferably contains a rubber-based binder, although not particularly limited.

[0036] (Conductive aid) The conductive aid is not particularly limited. The conductive aid may be, for example, vapor-grown carbon fiber (VGCF), acetylene black (AB), ketjen black (KB), carbon nanotube (CNT), carbon nanofiber (CNF), etc., but is not limited thereto. The conductive aid may be, for example, particulate or fibrous, and its size is not particularly limited. The conductive aid is not particularly limited, and only one type may be used alone, or two or more types may be used in combination.

[0037] (Particle size of the electrode binder slurry) The particle size of the electrode binder slurry for the solid battery of the present disclosure measured by the particle gauge method is 60 μm or less.

[0038] The particle size of the above electrode binder slurry measured by the particle gauge method can be evaluated according to JIS K5600-2-5 (1999). Specifically, the electrode binder slurry is dropped on the particle gauge stage, thinly spread in the gauge groove with a scraper, and the point at which prominent spots begin to appear on the gauge is observed to obtain the particle size. Therefore, the particle size measured by the particle gauge method corresponds to the maximum particle size. The particle size of the electrode binder slurry measured by the particle gauge method may be 50 μm or less, 45 μm or less, or 40 μm or less, and may also be 1 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more.

[0039] "Method for Manufacturing Electrode Composite Slurry" The electrode composite slurry for a solid-state battery according to the present disclosure can be manufactured by the following steps: providing a preliminary electrode composite slurry containing an electrode active material, a solid electrolyte, and a dispersion medium, and (i) applying a dispersion energy of 1.0×10 6 J / L or more to the preliminary electrode composite slurry to stir the preliminary electrode composite slurry to prepare an electrode composite slurry, and / or (ii) with respect to the particle diameter measured by the particle gauge method when applying a dispersion energy of 5.0×10 5 J / L to the preliminary electrode composite slurry and stirring, stirring the preliminary electrode composite slurry until the particle diameter measured by the particle gauge method becomes 0.75 times or less to prepare an electrode composite slurry.

[0040] According to the method for manufacturing an electrode composite slurry for a solid-state battery of the present disclosure, an electrode composite slurry for forming an electrode active material layer that reduces battery resistance can be obtained.

[0041] The present inventors studied the dispersion energy when preparing the electrode composite slurry, and found that an electrode active material layer with reduced resistance can be obtained by using an electrode composite slurry to which a dispersion energy of 1.0×10 6 J / L or more is applied.

[0042] Also, immediately after applying the dispersion energy, it is difficult to measure the particle diameter by the particle gauge method because the preliminary electrode composite slurry is non-uniform. On the other hand, when applying a dispersion energy of 5.0×10 5 J / L to the preliminary electrode composite slurry and stirring, the non-uniformity of the preliminary electrode composite slurry is eliminated, and the particle diameter can be easily measured by the particle gauge method. And it was found that an electrode active material layer with reduced resistance can also be obtained when using an electrode composite slurry to which a dispersion energy is applied until the particle diameter becomes 0.75 times or less with respect to the particle diameter measured by the particle gauge method when applying a dispersion energy of 5.0×10 5 J / L to the preliminary electrode composite slurry and stirring.

[0043] <Provision of the preliminary electrode composite slurry> The preliminary electrode composite slurry of the present disclosure contains an electrode active material, a solid electrolyte, and a dispersion medium.

[0044] Regarding the electrode active material, solid electrolyte, and dispersion medium contained in the preliminary electrode composite slurry, reference can be made to the description in "<Constitution of the electrode composite slurry for a solid battery>" above. The preliminary electrode composite slurry is a precursor of the electrode composite slurry, and the particle diameter measured by the particle gauge method of the preliminary electrode composite slurry is not particularly limited.

[0045] As the preliminary electrode composite slurry, those prepared by mixing an electrode active material, a solid electrolyte, and a dispersion medium may be used, or those obtained by mixing an electrode active material, a solid electrolyte, and a dispersion medium may be used.

[0046] <Application of dispersion energy> The method for manufacturing the electrode composite slurry for a solid battery of the present disclosure is (i) Applying a dispersion energy of 1.0×10 6 J / L or more to the preliminary electrode composite slurry and stirring the preliminary electrode composite slurry to prepare the electrode composite slurry, and / or (ii) Stirring the preliminary electrode composite slurry until the particle diameter measured by the particle gauge method becomes 0.75 times or less of the particle diameter measured by the particle gauge method when a dispersion energy of 5.0×10 5 J / L is applied and stirred to prepare the electrode composite slurry.

[0047] (Dispersion energy) The dispersing energy can be applied using, for example, an ultrasonic homogenizer (US600AT manufactured by Nippon Seiki Co., Ltd.), but is not limited to this case. The dispersing energy can be calculated from the output and time when applying the dispersing energy. When using an ultrasonic homogenizer (US600AT manufactured by Nippon Seiki Co., Ltd.), the output applied to the preliminary electrode composite slurry is not particularly limited, but may be 150 W or more, 200 W or more, or 250 W or more, and may also be 650 W or less, 600 W or less, or 550 W or less.

[0048] The dispersing energy applied to the preliminary electrode composite slurry is 1.5×10 6 J / L or more, 2.0×10 6 J / L or more, or 2.5×10 6 J / L or more, and may also be 1.0×10 8 J / L or less, 1.0×10 7 J / L or less, 8.0×10 6 J / L or less, or 6.0×10 6 J / L or less.

[0049] The method of stirring is not particularly limited, and a general method capable of stirring the electrode composite slurry can be used.

[0050] <Other> Using the electrode composite slurry of the present disclosure, an electrode active material layer can be manufactured by a known method. For example, an electrode composite slurry containing various components can be applied onto a substrate, dried, and an electrode active material layer can be formed.

[0051] The method of forming a solid-state battery is not particularly limited, and a known method can be adopted. As a method of forming a solid-state battery, for example, 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 are arranged in this order, laminated and sealed, and a solid-state battery can be formed, but is not limited to this case. The solid-state battery is not particularly limited, but may be constrained by an external pressure of, for example, 5 MPa.

[0052] In addition, by observing the SEM image of the cross-section of the electrode active material layer of the solid battery, it can be determined that the particle diameter measured by the particle gauge method of the electrode composite slurry used for forming the solid battery is 60 μm or less. As described above, since the particle diameter measured by the particle gauge method corresponds to the maximum particle diameter contained in the electrode composite slurry, if the maximum particle diameter observed in the SEM image is 60 μm or less, it can be determined that the particle diameter measured by the particle gauge method is 60 μm or less.

Example

[0053] The present disclosure will be described in more detail with reference to the examples shown below, but the scope of the present disclosure is not limited to these examples.

[0054] 《Example 1》 〈Preparation of Electrode Composite Slurry A1 for Negative Electrode〉 Li as a negative electrode active material 4 Ti 5 O 12 particles, Li as a solid electrolyte 2 S-P 2 S 5 system glass ceramics, a styrene-butadiene rubber (SBR) system binder as a binder, conductive carbon as a conductive aid, a dispersant, and tetralin as an appropriate amount of dispersion medium were mixed, and a dispersion energy of 1.0×10 6 J / L was applied and stirred to obtain electrode composite slurry A1 for the negative electrode. The dispersion energy was calculated from the output and time of the ultrasonic homogenizer. The particle diameter of the composite slurry A1 for the negative electrode measured by the particle gauge method was 60 μm.

[0055] 〈Fabrication of Negative Electrode Active Material Layer B1〉 On both sides of the aluminum foil as the negative electrode current collector, the negative electrode electrode mixture slurry A1 was applied by die coating, dried, and the negative electrode active material layer B1 was formed on both sides of the aluminum foil. The negative electrode active material layer B1 had a uniform appearance without streaks or unevenness. The basis weight of the negative electrode active material layer was adjusted so that the charge specific capacity of the positive electrode active material contained in the positive electrode active material layer was 200 mAh / g, and the charge capacity of the negative electrode active material layer was twice that.

[0056] <Fabrication of Solid Electrolyte Layer C1> LiI-Li as a solid electrolyte 2 S-P 2 S 5 The LiI-Li S-P-S based glass ceramics as a solid electrolyte, an SBR-based binder as a binder, a conductive carbon as a conductive aid, a dispersant, and tetralin as an appropriate amount of dispersion medium were mixed and dispersed by an ultrasonic homogenizer (US600AT manufactured by Nippon Seiki Co., Ltd.) to obtain a solid electrolyte composite slurry. Next, the solid electrolyte composite slurry was applied by die coating on the aluminum foil and dried to form the solid electrolyte layer C1 on the aluminum foil.

[0057] <Fabrication of Positive Electrode Active Material Layer D1> LiNi coated with a Li-Ti-Al-F based material as a positive electrode active material 0.8 (CoAl) 0.2 O 2 and Li as a solid electrolyte 2 S-P 2 S 5 The Li S-P-S based glass ceramics as a solid electrolyte, an SBR-based binder as a binder, a conductive carbon as a conductive aid, a dispersant, and tetralin as an appropriate amount of dispersion medium were mixed and dispersed by an ultrasonic homogenizer (US600AT manufactured by Nippon Seiki Co., Ltd.) to obtain a positive electrode electrode mixture slurry. Next, the positive electrode composite slurry was applied by die coating on the aluminum foil and dried to form the positive electrode active material layer D1 on the aluminum foil.

[0058] <Fabrication of All-Solid-State Battery E1> A solid electrolyte layer C1 was superposed on each surface of the negative electrode active material layer B1 formed on both sides of the aluminum foil, and pressed, whereby the solid electrolyte layer C1 was transferred onto the surface of the negative electrode active material layer B1, and the aluminum foil in contact with the solid electrolyte layer C1 was peeled off, and the solid electrolyte layer C1 was laminated on the negative electrode active material layer B1. Next, a positive electrode active material layer D1 was superposed on each surface of the solid electrolyte layer C1 formed on both sides of the negative electrode active material layer B1, and pressed, whereby the positive electrode active material layer D1 was transferred onto the surface of the solid electrolyte layer C1, and the aluminum foil in contact with the positive electrode active material layer D1 was peeled off, and the positive electrode active material layer D1 was laminated on the solid electrolyte layer C1. The produced laminate was roll-pressed at 175 °C and 5 ton / cm to obtain a densified laminate. Then, carbon-coated aluminum foil as a positive electrode current collector was disposed on each surface of the positive electrode active material layer of the densified laminate, and pressed at 140 °C and 5 MPa for 5 minutes to obtain a power generation element. Here, the power generation element was laminated in the order of carbon-coated aluminum foil, positive electrode active material layer D1, solid electrolyte layer C1, negative electrode active material layer B1, aluminum foil, negative electrode active material layer B1, solid electrolyte layer C1, positive electrode active material layer D1, carbon-coated aluminum foil. The obtained power generation element was laminated and encapsulated and constrained at 5 MPa to obtain an all-solid-state battery E1.

[0059] 〈Measurement of Resistance of All-Solid-State Battery E1〉 The all-solid-state battery E1 was charged at a constant current equivalent to 0.3C until the voltage reached a value equivalent to a charge depth of 50%, and then the all-solid-state battery E1 was discharged for 2 seconds with a current value of 46C. The potential difference between the voltage before discharge and the voltage after 2-second discharge was obtained, and the battery resistance was calculated by dividing the potential difference by the current value equivalent to 46C. The battery resistance of the all-solid-state battery C1 was 5.1 Ω.

[0060] 《Example 2》 〈Preparation of Electrode Composite Slurry A2 for Negative Electrode〉 Except that the dispersion energy was 2.5×10 6 J / L, an electrode composite slurry for negative electrode was prepared in the same manner as in Example 1 to obtain an electrode composite slurry A2 for negative electrode. The particle diameter of the electrode composite slurry A2 for negative electrode measured by the particle gauge method was 40 μm.

[0061] <Preparation of the negative electrode active material layer B2> A negative electrode active material layer was prepared in the same manner as in Example 1 except that the electrode mixture slurry A2 for the negative electrode was used, and the negative electrode active material layer B2 was obtained. The negative electrode active material layer B2 had a uniform appearance without streaks or unevenness.

[0062] <Preparation of the all-solid-state battery E2 and resistance measurement> An all-solid-state battery was prepared in the same manner as in Example 1 except that the negative electrode active material layer B1 was used, and the all-solid-state battery E2 was obtained. The battery resistance of the all-solid-state battery E2 was calculated in the same manner as that of the all-solid-state battery E1. The battery resistance of the all-solid-state battery E2 was 5.0 Ω.

[0063] <<Comparative Example 1>> <Preparation of the electrode mixture slurry a1 for the negative electrode> An electrode mixture slurry for the negative electrode was prepared in the same manner as in Example 1 except that no dispersion energy was applied, that is, the dispersion energy was set to 0 J / L, and the electrode mixture slurry a1 for the negative electrode was obtained. The particle diameter of the electrode mixture slurry a1 for the negative electrode measured by the particle gauge method was 100 μm or more.

[0064] <Preparation of the negative electrode active material layer b1> A negative electrode active material layer was prepared in the same manner as in Example 1 except that the electrode mixture slurry a1 for the negative electrode was used, and the negative electrode active material layer b1 was obtained. The negative electrode active material layer b1 had a non-uniform appearance with streaks and unevenness.

[0065] <Preparation of the all-solid-state battery e1> Since there were many streaks and unevenness in the negative electrode active material layer b1, the all-solid-state battery e1 could not be prepared.

[0066] <<Comparative Example 2>> <Preparation of the electrode mixture slurry a2 for the negative electrode> An electrode mixture slurry for the negative electrode was prepared in the same manner as in Example 1 except that the dispersion energy was set to 5.0×10 5 J / L, and the electrode mixture slurry a2 for the negative electrode was obtained. The particle diameter of the electrode mixture slurry a2 for the negative electrode measured by the particle gauge method was 80 μm.

[0067] <Production of the negative electrode active material layer b2> A negative electrode active material layer was produced in the same manner as in Example 1 except that the electrode mixture slurry a2 for the negative electrode was used, and the negative electrode active material layer b2 was obtained. The negative electrode active material layer b2 had a uniform appearance without streaks or unevenness.

[0068] <Production of the all-solid-state battery e2 and measurement of resistance> An all-solid-state battery was produced in the same manner as in Example 1 except that the negative electrode active material layer b2 was used, and the all-solid-state battery e2 was obtained. The battery resistance of the all-solid-state battery e2 was calculated in the same manner as that of the all-solid-state battery C1. The battery resistance of the all-solid-state battery e2 was 5.6 Ω.

[0069] Table 1 shows the results of Example 1, 2 and Comparative Example 1, 2.

[0070]

Table 1

[0071] When the particle size measured by the particle gauge method was 60 μm as in the electrode mixture slurry A1 for the negative electrode of Example 1, an electrode active material layer with a uniform appearance could be obtained, and the battery resistance of the all-solid-state battery including the electrode active material layer formed from this electrode mixture slurry was sufficiently low. On the other hand, even when the particle size measured by the particle gauge method was 80 μm as in the electrode mixture slurry a2 for the negative electrode of Comparative Example 2, an electrode active material layer with a uniform appearance could be obtained. However, the battery resistance of the all-solid-state battery e2 including the electrode active material layer formed from this electrode mixture slurry showed a high value of 5.6 Ω. It became clear that by setting the particle size of the electrode mixture slurry measured by the particle gauge method to 60 μm or less, not only a uniform electrode active material layer can be obtained, but also an electrode active material layer that can reduce the battery resistance can be obtained.

[0072] FIG. 1 shows the relationship between the dispersion energy and the particle size of the electrode composite material slurry measured by the particle gauge method for Examples 1 and 2 and Comparative Example 2. It was found from FIG. 1 that as the dispersion energy increases, the particle size obtained by the particle gauge method decreases. In particular, by applying a dispersion energy of 1.0×10 6 J / L or more, the particle size measured by the particle gauge method became 60 μm or less. Regarding the negative electrode composite material slurry A1 of Example 1 to which a dispersion energy of 1.0×10 6 J / L was applied, the battery resistance of the all-solid-state battery E1 obtained from this negative electrode composite material slurry was sufficiently low. By applying a dispersion energy of 1.0×10 6 J / L or more, the particle size of the electrode composite material slurry measured by the particle gauge method became sufficiently small, and thereby, it is considered that an electrode active material layer capable of reducing the battery resistance could be obtained.

[0073] Although the preferred embodiments of the electrode composite material slurry for a solid-state battery and the method for manufacturing the electrode composite material slurry of the present disclosure have been described, those skilled in the art understand that modifications can be made 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, and a dispersion medium, The particle diameter of the electrode mixture slurry measured by a particle gauge method is 60 μm or less; Electrode mixture slurry.

2. The electrode mixture slurry of claim 1 , wherein the electrode mixture slurry contains a rubber-based binder.

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

4. A method for producing the electrode mixture slurry according to any one of claims 1 to 3, comprising the following steps: Providing a preliminary electrode mixture slurry containing an electrode active material, a solid electrolyte, and a dispersion medium; and (i) Add 1.0×10 ６ (ii) applying a dispersion energy of 5.0×10 to the preliminary electrode mixture slurry to stir the preliminary electrode mixture slurry, and / or ５ The preliminary electrode mixture slurry is stirred until the particle diameter measured by the particle gauge method becomes 0.75 times or less of the particle diameter measured by the particle gauge method when stirring is performed by applying a dispersion energy of J / L, thereby preparing the electrode mixture slurry.

5. An electrode active material layer for a solid-state battery, The maximum particle size of the electrode active material and the solid electrolyte measured from a SEM image of a cross section of the electrode active material layer is 60 μm or less. Electrode active material layer.

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