Manufacturing method for positive electrode material

Abstract

To provide a method of manufacturing a positive electrode material capable of reducing an amount of a dispersion medium when slurry is generated.SOLUTION: A method of manufacturing a positive electrode material of a solid-state battery 1 includes: a first combining step of mixing a positive electrode active material PAM and a solid electrolyte SE to generate a first powder 21; and a second combining step of mixing the solid electrolyte SE to the first powder 21 under a stirring condition different from that of the first combining step to generate a second powder 22.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a positive electrode material. [Background technology]

[0002] In recent years, research and development has been conducted on rechargeable batteries that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable, and advanced energy.

[0003] Lithium-ion rechargeable batteries are widely used as secondary batteries. Lithium-ion rechargeable batteries, which use a liquid as an electrolyte, have a structure in which a separator is present between the positive and negative electrodes, and the battery is filled with a liquid electrolyte (electrolyte solution).

[0004] The electrolyte in lithium-ion secondary batteries is usually a flammable organic solvent, which has sometimes raised safety concerns, particularly regarding heat. Therefore, solid-state batteries using flame-retardant solid electrolytes instead of organic liquid electrolytes have also been proposed.

[0005] Solid-state rechargeable batteries have an electrolyte layer between the positive and negative electrodes, consisting of an inorganic solid electrolyte, an organic solid electrolyte, or a gel-like solid electrolyte. Compared to batteries that use liquid electrolytes, solid-state batteries with solid electrolytes eliminate thermal problems, can achieve higher capacity and / or higher voltage, and can also meet the demand for compact designs.

[0006] Various methods for manufacturing the positive electrode material of such lithium-ion secondary batteries have been proposed (for example, Patent Documents 1 to 4). For example, Patent Document 1 describes the process of creating secondary particles by mixing a sulfide-based solid electrolyte with positive electrode active material particles coated with an oxide-based solid electrolyte. Generally, the positive electrode of a secondary battery is made by mixing a positive electrode active material, a solid electrolyte, and a dispersion medium containing a binder to form a slurry, which is then applied to a current collector and dried. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2020 / 174868 [Patent Document 2] Japanese Patent Publication No. 2011-65887 [Patent Document 3] Japanese Patent Publication No. 2016-42417 [Patent Document 4] International Publication No. 2012 / 001808 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In the slurry generation process, it is preferable to use as little dispersion medium as possible. Reducing the dispersion medium can lower manufacturing costs and time. After careful consideration by the inventors, it was found that reducing the dispersion medium requires compounding the positive electrode active material and solid electrolyte to reduce the total surface area of ​​the entire material, and therefore there was room for improvement in conventional methods.

[0009] This invention provides a method for manufacturing a cathode material that can reduce the amount of dispersion medium used when generating a slurry. This, in turn, contributes to energy efficiency. [Means for solving the problem]

[0010] This invention One aspect teeth, A method for manufacturing a positive electrode material for a solid-state battery, A first compounding step involves mixing a positive electrode active material and a solid electrolyte to produce a first powder, The process includes a second compounding step in which the solid electrolyte is mixed with the first powder under different stirring conditions than those of the first compounding step to produce a second powder. 、 The second compounding step is performed at a slower stirring speed than the first compounding step. The second compounding step has a shorter stirring time than the first compounding step. . Another aspect of the present invention is: A method for manufacturing a positive electrode material for a solid-state battery, A first compounding step involves mixing a positive electrode active material and a solid electrolyte to produce a first powder, The process comprises a second compounding step in which the solid electrolyte is mixed with the first powder under different stirring conditions than those of the first compounding step to produce a second powder, The second composite step involves a smaller shear force than the first composite step. The second compounding step involves a shorter stirring time than the first compounding step. [Advantages of the Invention]

[0011] According to the present invention, the amount of the dispersion medium when generating a slurry in manufacturing a positive electrode material can be reduced. [Brief Description of the Drawings]

[0012] [Figure 1] It is a cross-sectional view of the solid battery 1. [Figure 2] It is a flowchart schematically showing a method for manufacturing a positive electrode material. [Figure 3] It is a table showing the experimental results of Examples and Comparative Examples 1 and 2. [Figure 4] It is a schematic diagram showing the state of particles dispersed in a slurry. [Embodiments for Carrying Out the Invention]

[0013] First, a solid battery using a positive electrode material manufactured by the manufacturing method of the present invention will be described. [Solid Battery] As shown in FIG. 1, the solid battery 1 includes a battery body 10, a negative electrode current collector 50, and a positive electrode current collector 60. In the present specification, the solid battery refers to a battery in which the battery is fully solidified.

[0014] The negative electrode current collector 50 and the positive electrode current collector 60 are conductive plate-shaped members that sandwich the battery body 10 from both sides. The negative electrode current collector 50 has the function of collecting current from the negative electrode layer 30, and the positive electrode current collector 60 has the function of collecting current from the positive electrode layer 20. The battery body 10 comprises a positive electrode layer 20 that functions as a positive electrode, a negative electrode layer 30 that functions as a negative electrode, and a conductive solid electrolyte layer 40 located between the positive electrode layer 20 and the negative electrode layer 30. The positive electrode layer 20 is manufactured by applying a slurry containing a positive electrode active material, a conductive additive, and a solid electrolyte to the positive electrode current collector 60 and drying it.

[0015] [Manufacturing method for positive electrode material] Hereinafter, one embodiment of the method for manufacturing the cathode material of the present invention will be described with reference to Figure 2. The method for manufacturing the positive electrode material includes the following steps. 1. A first compounding step in which the positive electrode active material PAM and the solid electrolyte SE are mixed to produce a first powder 21. 2. A second compounding step in which solid electrolyte SE is mixed with the first powder 21 under different stirring conditions than the first compounding step to produce the second powder 22. 3. A slurry generation step in which the second powder 22 is mixed with a dispersion medium containing a conductive additive CA, a solvent, and a binder. 4. Slurry application step: Applying slurry onto the current collector.

[0016] The method for manufacturing the cathode material in this embodiment differs from conventional manufacturing methods in which a sulfide-based solid electrolyte is mixed with cathode active material particles coated with an oxide-based solid electrolyte to form secondary particles (compounds). In conventional manufacturing methods, although the total surface area of ​​the particles becomes smaller compared to cases where secondary particle formation (compounding) is not performed, and the amount of dispersion medium can be reduced, the amount of dispersion medium is still large and there is room for improvement.

[0017] Therefore, in the manufacturing method of the positive electrode material of this embodiment, as shown in Figure 2, a solid electrolyte SE is dry-mixed with a positive electrode active material PAM to coat the surface of the positive electrode active material PAM with the solid electrolyte SE to produce a first powder 21. In the first powder 21, the solid electrolyte SE adheres closely to the surface of the positive electrode active material PAM. Then, the solid electrolyte SE is dry-mixed with the obtained first powder 21 to fix the solid electrolyte SE in a manner supported on the first powder 21. In the second powder 22, the solid electrolyte SE adheres to the surface of the positive electrode active material PAM (the surface of the solid electrolyte SE) to which the solid electrolyte SE has adhered. In this way, by achieving both a dense adhesion state and a rough adhesion state of the solid electrolyte SE to the positive electrode active material PAM, the contact area between the positive electrode active material PAM and the solid electrolyte SE (sulfide-based solid electrolyte SE2 described later) is secured, while ensuring contact between electrons and lithium ions (Li + This allows for the simultaneous establishment of conduction paths. Furthermore, if the compounding is insufficient, the amount of dispersion medium required for slurry formation will be large due to the large surface area of ​​the particles, but by ensuring sufficient compounding, the amount of dispersion medium can be reduced.

[0018] In the first compounding step, the positive electrode active material PAM acts as the mother particle, and the solid electrolyte SE acts as the daughter particle, with the daughter particle coating the surface of the mother particle in a thin film (first powder). In the second compounding step, the first powder acts as the mother particle, and the solid electrolyte SE acts as the daughter particle, with the daughter particle adhering to the surface of the mother particle while maintaining its particulate form (second powder). Compounding means that by breaking down and dispersing aggregates of each material with a shear stress above a certain level, van der Waals forces due to the difference in particle size act between the larger mother particle and the smaller daughter particle, resulting in the formation of composite particles. Hereinafter, particles mixed after the first and second compounding steps may be referred to as composite particles.

[0019] To separate the compounding steps, assuming the amount of solid electrolyte SE originally required is 1, half of the solid electrolyte SE is mixed with the positive electrode active material PAM in the first compounding step, and the remaining half of the solid electrolyte SE is mixed with the first powder in the second compounding step. The proportions of solid electrolyte SE mixed in the first and second compounding steps can be changed as appropriate.

[0020] In the case of composite particles in which the solid electrolyte SE is bonded to the positive electrode active material PAM in a dense adhesion state and a rough adhesion state, the total surface area becomes smaller. As a result, the amount of dispersion medium required for slurrying, that is, the amount of solvent and binder can be reduced. In addition, by previously dispersing the composite particles, the time required for dispersion during slurrying can be shortened. Also, since the amount of solvent is reduced, the drying time after slurry coating can be shortened. Furthermore, since the amount of binder is reduced, the resistance of the electrode can be reduced. Note that "dry process" means mixing without using a dispersion medium. Hereinafter, each step will be described in detail.

[0021] [First Composite Step] In the first composite step, the positive electrode active material PAM and the solid electrolyte SE are mixed dry to produce the first powder 21.

[0022] Examples of the positive electrode active material PAM include oxides having lithium and cobalt as constituent metal elements, and oxides containing at least one other metal element in addition to lithium and cobalt as constituent metal elements. Examples of metal elements other than lithium and cobalt include, for example, Ni, Mn, Al, Cr, Fe, V, Mg, Ca, Na, Ti, Zr, Nb, Mo, W, Cu, Zn, Ga, In, Sn, La, and Ce. These may include not only one kind but also two or more kinds.

[0023] Examples of the positive electrode active material PAM include, for example, LiCoO2. In addition, lithium nickel cobalt manganese-based oxides (NCM) represented by the following general formula (1) can be mentioned. NCM is preferable in that it has a high energy density per unit volume and excellent thermal stability. LiNi a Co b Mn c O2(1) (In the formula, 0 < a < 1, 0 < b < 1, 0 < c < 1, and a + b + c = 1 is satisfied.)

[0024] In addition, examples of the positive electrode active material PAM include lithium nickel cobalt aluminum-based oxides (NCA) represented by the following general formula (2). Li t Ni 1-x-y Co x Al y O2(2) (In the formula, 0.95 ≦ t ≦ 1.15, 0 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0.2, and x + y < 0.5.)

[0025] It is preferable that the surface of the positive electrode active material PAM is previously coated with an oxide-based solid electrolyte. By coating the surface of the positive electrode active material PAM with an oxide-based solid electrolyte, the interfacial resistance between the positive electrode active material PAM and the sulfide-based solid electrolyte in contact with it can be reduced, and the ionic conductivity can be improved.

[0026] Note that the coating with the oxide-based solid electrolyte is preferably in the form of a film without grain boundaries and covers all of the surface of the positive electrode active material. Thereby, the grain boundary resistance of the particles after coating can be reduced. Such a film-like coating layer without grain boundaries is formed, for example, by spray coating.

[0027] Examples of the oxide-based solid electrolyte include LiNbO3 in the case of a lithium ion battery. In addition, NASICON-type oxides, garnet-type oxides, perovskite-type oxides, etc. can be mentioned. Examples of NASICON-type oxides include oxides containing Li, Al, Ti, P, and O (for example, Li 1.5 Al 0.5 Ti 1.5 (PO4)3). Examples of garnet-type oxides include oxides containing Li, La, Zr, and O (for example, Li7La3Zr2O 12 ). Examples of perovskite-type oxides include oxides containing Li, La, Ti, and O (for example, LiLaTiO3). Note that the coating of the oxide-based solid electrolyte on the surface of the positive electrode active material PAM is not necessarily required.

[0028] Examples of solid electrolytes (SE) include sulfide-based solid electrolytes. Sulfide-based solid electrolyte materials typically contain a metal element (M) that acts as a conductive ion and sulfur (S). Examples of M include Li, Na, K, Mg, Ca, etc., with Li being particularly preferred. In particular, sulfide-based solid electrolyte materials preferably contain Li, A (A is at least one selected from the group consisting of P, Si, Ge, Al, and B), and S. Furthermore, A is preferably P (phosphorus). In addition, sulfide-based solid electrolyte materials may also contain halogens such as Cl, Br, and I. This is because the inclusion of halogens improves ionic conductivity. Furthermore, sulfide-based solid electrolyte materials may also contain O.

[0029] Examples of sulfide-based solid electrolyte materials having Li ion conductivity include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, and Li2S-P2S5-Z. m S n (where m and n are positive numbers, and Z is one of Ge, Zn, or Ga.) Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (wherein x and y are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, or In.) These are some examples. The above description of "Li2S-P2S5" refers to a sulfide-based solid electrolyte material made using a raw material composition containing Li2S and P2S5, and the same applies to other descriptions.

[0030] In the following explanation, among solid electrolytes SE, oxide-based solid electrolytes will be referred to as SE1 and sulfide-based solid electrolytes as SE2, and these will be described separately. As shown in the upper part of Figure 2, in the first composite step, sulfide-based solid electrolyte SE2 is coated onto the surface of the positive electrode active material PAM or the surface of the positive electrode active material PAM coated with oxide-based solid electrolyte SE1 (the surface of oxide-based solid electrolyte SE1) to ensure close adhesion of the sulfide-based solid electrolyte SE2. In order to form such a dense sulfide-based solid electrolyte layer, a composite treatment involving high shear force is necessary. A composite treatment involving high shear force refers to a mixing treatment by high-speed stirring.

[0031] High-speed stirring is used for mixing by rotating the mixer at high speed. The stirring speed is preferably 60 m / s to 100 m / s, and more preferably 70 m / s to 80 m / s. The stirring time is preferably 50 to 70 minutes, more preferably 55 to 65 minutes, and most preferably around 60 minutes.

[0032] [Second Combination Step] In the second compounding step, as shown in the middle of Figure 2, the first powder 21 obtained in the first compounding step and the sulfide-based solid electrolyte SE2 are mixed dry to produce the second powder 22. Here, the mixing process in the second compounding step is carried out under different stirring conditions than the mixing process in the first compounding step. That is, a compounding process with lower shear force is performed compared to the first compounding step. A compounding process with low shear force refers to a mixing process using low-speed stirring and medium-speed stirring.

[0033] In the second compounding step, the mixing process is carried out by rotating the mixer at a medium to high speed. The stirring speed is preferably 40 m / s to 80 m / s, and more preferably 60 m / s to 70 m / s. The stirring time is preferably 30 minutes or less, and more preferably 20 minutes or less.

[0034] Comparing the first and second compounding steps, the stirring speed in the second compounding step is slower than in the first compounding step. In other words, the shear force in the second compounding step is smaller than in the first compounding step. Furthermore, it is preferable that the stirring time in the second compounding step is shorter than in the first compounding step. This allows the first compounding step to coat the surface of the positive electrode active material PAM with the sulfide-based solid electrolyte SE2, and the second compounding step to support the bulk sulfide-based solid electrolyte SE2 on the particles produced in the first compounding step. In addition, it is possible to suppress the reduction in particle size of the bulk sulfide-based solid electrolyte SE2.

[0035] [Slurry generation step] In the slurry generation step, as shown in the lower part of Figure 2, the second powder 22 is mixed with a dispersion medium (auxiliary dispersion medium) containing the conductive additive CA, solvent, and binder.

[0036] The solvent is not particularly limited and can include, for example, organic solvents such as N-methyl-2-pyrrolidone (NMP), toluene, or alcohol, or water.

[0037] Examples of conductive additives (CA) include acetylene black, carbon nanotubes, graphene, and graphite particles.

[0038] Examples of binders include polyvinylidene fluoride (PVDF), polyvinylidene chloride (PVDC), polyethylene oxide (PEO), polypropylene oxide (PPO), and polyethylene oxide-propylene oxide copolymer (PEO-PPO).

[0039] [Slurry application step] The slurry coating step can be carried out using known methods. Examples include roller coating using an applicator roll, screen coating, blade coating, spin coating, and bar coating.

[0040] In the positive electrode material of a solid-state battery manufactured by the manufacturing method of the present invention, the positive electrode layer may be formed on at least one side of the current collector, or it may be formed on both sides. This can be appropriately selected depending on the type and structure of the solid-state battery to be manufactured. After applying the slurry onto the current collector, steps such as drying and rolling may be added.

[0041] [Examples of reducing the amount of dispersion medium] Figure 3 is a table showing experimental results comparing battery capacity (theoretical capacity), resistance, slurry viscosity, and powder surface area in the embodiment of the present invention and two comparative examples.

[0042] The examples are cathode materials manufactured by the cathode material manufacturing method described above. Specifically, the second powder 22 obtained through the first and second compounding steps is dispersed in a dispersion medium (conductive additive CA, solvent, binder) to form a cathode material from the resulting slurry. Reference Example 1 (no compounding treatment) is a cathode material formed by dispersing a cathode active material PAM coated with an oxide-based solid electrolyte SE1 and a sulfide-based solid electrolyte SE2 in a dispersion medium (conductive additive CA, solvent, binder) without compounding treatment, from the resulting slurry. Reference Example 2 (first compounding treatment only, no second compounding treatment) is a cathode material formed by dispersing a first powder 21, which is a compound of the cathode active material PAM coated with an oxide-based solid electrolyte SE1 and a sulfide-based solid electrolyte SE2 in the first compounding step, and a sulfide-based solid electrolyte SE2 in a dispersion medium (conductive additive CA, solvent, binder) without compounding treatment, from the resulting slurry. Furthermore, the positive electrode active material PAM coated with oxide-based solid electrolyte SE1, and the sulfide-based solid electrolyte SE2 are the same and in the same amounts in both the example and Reference Examples 1 and 2.

[0043] Battery capacity is the theoretical value of the battery capacity per gram of positive electrode active material. Slurry viscosity is the degree of stickiness of the material. Since the viscosity of the slurry changes with the shear rate, in this disclosure, viscosity refers to the viscosity at a shear rate of around 75 [1 / s]. Resistance is the internal resistance at the positive electrode. The resistance of the positive electrode is due to the large contact area between the positive electrode active material and the sulfide-based solid electrolyte, and the interaction between electrons and lithium ions (Li+ It is desirable that the conduction path is sufficiently formed throughout the entire positive electrode, in which case the resistance will be low. The solvent of the dispersion medium is an unnecessary material that evaporates after slurry coating. The smaller the surface area, the smaller the contact area with the dispersion medium, and therefore the amount of dispersion medium can be reduced.

[0044] As shown in the experimental results in Figure 3, Comparative Example 2 showed better results than Comparative Example 1 in all items. Furthermore, the Example also showed better results than Comparative Example 2 in all items.

[0045] Figure 4 is a schematic diagram showing the state of particles dispersed in a slurry. Without the second compounding treatment (Comparative Example 2), the first powder 21, in which the surface of the positive electrode active material PAM particles coated with oxide-based solid electrolyte SE1 is coated with sulfide-based solid electrolyte SE2, and the sulfide-based solid electrolyte SE2 exist separately in the dispersion medium. As a result, the total surface area of ​​the powder increases, and the amount of dispersion medium required increases. On the other hand, with the second compounding treatment (Example), the sulfide-based solid electrolyte SE2 adheres in bulk to the surface of the first powder 21, so the total surface area of ​​the powder decreases, and less dispersion medium is required.

[0046] Thus, according to the method for manufacturing the positive electrode material of the present invention, in the first composite step, the surface of the positive electrode active material PAM is coated with solid electrolyte SE, and in the second composite step, bulk solid electrolyte SE is supported on the particles generated in the first composite step, making it possible to achieve both a dense adhesion state and a rough adhesion state of the solid electrolyte SE. This ensures a contact area between the positive electrode active material PAM and the solid electrolyte SE (solid electrolyte SE2), while allowing electrons and lithium ions (Li + This allows for the simultaneous creation of conduction paths. Furthermore, since the total surface area of ​​the particles constituting the electrodes can be reduced, the amount of dispersion medium required when forming the slurry can be reduced.

[0047] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined in any way without departing from the spirit of the invention.

[0048] This specification contains at least the following information. Note that the components etc. in parentheses indicate those corresponding to the embodiments described above, but are not limited thereto.

[0049] (1) A method for manufacturing a positive electrode material for a solid-state battery (solid-state battery 1), A first compounding step involves mixing a positive electrode active material (positive electrode active material PAM) and a solid electrolyte (solid electrolyte SE) to produce a first powder (first powder 21), A method for producing a cathode material, comprising: a second compounding step of mixing the solid electrolyte with the first powder under stirring conditions different from those of the first compounding step to produce a second powder (second powder 22).

[0050] According to (1), by mixing the positive electrode active material with a solid electrolyte in two stages under different stirring conditions, two types of solid electrolyte layers can be attached to the positive electrode active material. As a result, the contact area of ​​the second powder with the dispersion medium is reduced when the particles combine to form a slurry, so the amount of dispersion medium required to produce the slurry can be reduced.

[0051] (2) A method for manufacturing a positive electrode material as described in (1), The method for manufacturing a cathode material, wherein the second compounding step is performed at a slower stirring speed than the first compounding step.

[0052] According to (2), in the first compounding step, a solid electrolyte is coated onto the surface of the positive electrode active material, and in the second compounding step, a bulk solid electrolyte is supported on the particles generated in the first compounding step. By achieving both a dense adhesion state and a loose adhesion state of the solid electrolyte in this way, it is possible to ensure a contact area between the positive electrode active material and the solid electrolyte while simultaneously providing conduction paths for electrons and ions. Furthermore, since the total surface area of ​​the particles constituting the electrode can be reduced, the amount of dispersion medium required when forming the slurry can be reduced.

[0053] (3) A method for manufacturing a positive electrode material as described in (1) or (2), The second composite step is a method for manufacturing a cathode material, wherein the shear force is smaller than that of the first composite step.

[0054] According to (3), in the first compounding step, a solid electrolyte is coated onto the surface of the positive electrode active material, and in the second compounding step, a bulk solid electrolyte is supported on the particles generated in the first compounding step. By achieving both a dense adhesion state and a loose adhesion state of the solid electrolyte in this way, it is possible to ensure a contact area between the positive electrode active material and the solid electrolyte while simultaneously providing conduction paths for electrons and ions. Furthermore, since the total surface area of ​​the particles constituting the electrode can be reduced, the amount of dispersion medium required when forming the slurry can be reduced.

[0055] (4) A method for manufacturing a positive electrode material as described in (2) or (3), A method for manufacturing a cathode material, wherein the second compounding step involves a shorter stirring time than the first compounding step.

[0056] According to (4), it is possible to suppress the reduction in particle size of bulk solid electrolytes.

[0057] (5) A method for manufacturing a positive electrode material as described in any of (1) to (4), A method for manufacturing a positive electrode material, wherein the positive electrode active material is coated with a solid electrolyte different from the solid electrolyte.

[0058] According to (5), the positive electrode active material can be protected.

[0059] (6) A method for manufacturing a positive electrode material as described in (5), The solid electrolyte is a sulfide-based solid electrolyte (sulfide-based solid electrolyte SE2), The method for manufacturing a cathode material, wherein the other solid electrolyte is an oxide-based solid electrolyte (oxide-based solid electrolyte SE1).

[0060] According to (6), the interfacial resistance between the positive electrode active material and the sulfide-based solid electrolyte can be reduced, thereby improving ionic conductivity.

[0061] (7) A method for manufacturing a positive electrode material as described in any of (1) to (6), A method for producing a positive electrode material, further comprising a slurry generation step of mixing the second powder with an additive dispersion medium containing a conductive additive (conductive additive CA).

[0062] According to (7), a slurry can be produced with a small amount of dispersion medium. [Explanation of Symbols]

[0063] 1 solid state battery 21 1st powder 22 Second powder CA Conductive Agent PAM positive electrode active material SE solid electrolyte SE1 Oxide solid electrolyte SE2 Sulfide solid electrolyte

Claims

1. A method for manufacturing a positive electrode material for a solid-state battery, A first compounding step involves mixing a positive electrode active material and a solid electrolyte to produce a first powder, The process comprises a second compounding step in which the solid electrolyte is mixed with the first powder under different stirring conditions than those of the first compounding step to produce a second powder, The second compounding step is performed at a slower stirring speed than the first compounding step. A method for manufacturing a cathode material, wherein the second compounding step involves a shorter stirring time than the first compounding step.

2. A method for manufacturing a positive electrode material for a solid-state battery, A first compounding step involves mixing a positive electrode active material and a solid electrolyte to produce a first powder, The process comprises a second compounding step in which the solid electrolyte is mixed with the first powder under different stirring conditions than those of the first compounding step to produce a second powder, The second composite step involves a smaller shear force than the first composite step. A method for manufacturing a cathode material, wherein the second compounding step involves a shorter stirring time than the first compounding step.

3. A method for manufacturing a positive electrode material according to claim 1 or 2, A method for manufacturing a positive electrode material, wherein the positive electrode active material is coated with a solid electrolyte different from the solid electrolyte.

4. A method for manufacturing a positive electrode material according to claim 3, The solid electrolyte is a sulfide-based solid electrolyte. The method for manufacturing a cathode material, wherein the other solid electrolyte is an oxide-based solid electrolyte.

5. A method for manufacturing a positive electrode material according to any one of claims 1 to 4, A method for producing a positive electrode material, further comprising a slurry generation step of mixing the second powder with an auxiliary dispersion medium containing a conductive additive.

6. A method for manufacturing a positive electrode material according to any one of claims 1 to 5, The stirring speed in the first compounding step is a peripheral speed of 60 m / s to 100 m / s. A method for manufacturing positive electrode material.

7. A method for manufacturing a positive electrode material according to any one of claims 1 to 6, The stirring time in the first compounding step is 50 to 70 minutes. A method for manufacturing positive electrode material.

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