JP7729752B2 - Sulfide-based inorganic solid electrolyte materials, solid electrolyte membranes, and all-solid-state lithium-ion batteries - Google Patents

Description

The present invention relates to a sulfide-based inorganic solid electrolyte material, a solid electrolyte membrane, and an all-solid-state lithium-ion battery.

Lithium-ion batteries are commonly used as power sources for small portable devices such as mobile phones and laptops. Recently, lithium-ion batteries have also begun to be used as power sources for electric vehicles and power storage, in addition to small portable devices.

Currently commercially available lithium-ion batteries use electrolytes containing flammable organic solvents. In contrast, lithium-ion batteries, which replace the electrolyte with a solid electrolyte and make the battery all-solid-state (hereafter referred to as all-solid-state lithium-ion batteries), do not use flammable organic solvents within the battery, which allows for simplified safety devices and is thought to offer superior manufacturing costs and productivity.

In recent years, solid electrolyte membranes containing primarily sulfide solid electrolyte materials have been used as solid electrolyte materials for such lithium-ion batteries. The sulfide-based inorganic solid electrolyte materials are primarily composed of, for example, lithium sulfide ( _Li2S ) and phosphorus _pentasulfide ( _P2S5 ).

Patent Document 1 (JP 2016-27545 A) describes a sulfide-based solid electrolyte material characterized by having a peak at 2θ=29.86°±1.00° in X-ray diffraction measurement using CuKα rays and having a composition of Li _2y+3 PS ₄ (0.1≦y≦0.175).

JP 2016-27545 A

However, it was found that the lithium ion conductivity of the sulfide-based inorganic solid electrolyte material obtained using conventional technology varies from production batch to production batch.

The present invention was made in consideration of these circumstances, and aims to provide a sulfide-based inorganic solid electrolyte material, a solid electrolyte membrane, and an all-solid-state lithium-ion battery that maintain ease of handling and lithium ion conductivity while minimizing variation in lithium ion conductivity between production batches.

The inventors conducted extensive research to solve this problem. As a result, they discovered that by sifting a sulfide-based inorganic solid electrolyte material onto a smooth metal plate, it is possible to reduce the variation in lithium ion conductivity between production batches while maintaining handleability and lithium ion conductivity, and to consistently obtain a sulfide-based inorganic solid electrolyte material with high lithium ion conductivity, leading to the present invention.

That is, according to the present invention,
A sulfide-based inorganic solid electrolyte material having a particle diameter _d50 of 0.1 μm or more and 100 μm or less when a cumulative frequency is 50% in a volume-based cumulative frequency distribution curve measured using a laser diffraction/scattering particle size distribution measuring device,
The adhesion area measured according to the following method is 10% or less.
A sulfide-based inorganic solid electrolyte material is provided.
(method)
(1) An SUS304 plate having an arithmetic mean roughness Ra of 0.017 μm or more and 0.023 μm or less, a maximum height Rz of 0.14 μm or more and 0.18 μm or less, and a ten-point mean roughness Rzjis of 0.12 μm or more and 0.16 μm or less, measured in accordance with JIS B 0601 (2013), and measuring 8 cm in length and 9 cm in width, is placed so that the vertical side is tangent to the horizontal plane and is inclined at an angle of 45° to the horizontal plane.
(2) Using a sieve with 250 μm openings, 10 g of the sulfide-based inorganic solid electrolyte material is sieved onto the SUS304 plate from a height of 10 cm from the horizontal surface so that the sulfide-based inorganic solid electrolyte material covers the entire SUS304 plate.
(3) A 47 g zirconia ball is dropped three times from a height of 5 cm from the upper end of the SUS304 plate so as to hit only the upper end of the SUS304 plate and not the surface of the SUS304 plate to which the sulfide-based inorganic solid electrolyte material is attached.
(4) After the impact, the area of the surface of the SUS304 plate to which the sulfide-based inorganic solid electrolyte material is attached is measured, and the ratio (attached area) to the area of one side of the SUS304 plate is calculated.

Further, according to the present invention,
There is provided a solid electrolyte membrane containing the above sulfide-based inorganic solid electrolyte material as a main component.

Further, according to the present invention,
An all-solid-state lithium ion battery including a positive electrode including a positive electrode active material layer, an electrolyte layer, and a negative electrode including a negative electrode active material layer,
There is provided an all-solid-state lithium ion battery in which at least one of the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer contains the sulfide-based inorganic solid electrolyte material.

The present invention makes it possible to provide a sulfide-based inorganic solid electrolyte material, a solid electrolyte membrane, and an all-solid-state lithium-ion battery that maintain ease of handling and lithium-ion conductivity while exhibiting little variation in lithium-ion conductivity between production batches.

1 is a diagram showing an apparatus according to an embodiment of the present invention; 2 is a top view of a rotary table and a plurality of balls of the grinding section shown in FIG. 1. 3 is a cross-sectional view taken along line AA' in FIG. 2. FIG. 4 is a diagram showing a modification of FIG. 3 . FIG. 1 is a cross-sectional view showing an example of the structure of an electrode for an all-solid-state lithium ion battery according to an embodiment of the present invention. FIG. 10 is a schematic diagram showing a measurement test of the adhesion area according to the present embodiment. FIG. 10 is a schematic diagram showing a measurement test of the adhesion area according to the present embodiment. FIG. 10 is a diagram showing the measurement results of the adhesion area according to the present embodiment.

Embodiments of the present invention will be described below with reference to the drawings. The drawings are schematic and do not necessarily correspond to the actual dimensional proportions. In this embodiment, unless otherwise specified, a layer formed from a positive electrode material will be referred to as a positive electrode active material layer, and a positive electrode active material layer formed on a current collector will be referred to as a positive electrode. Furthermore, a layer formed from a negative electrode material will be referred to as a negative electrode active material layer, and a negative electrode active material layer formed on a current collector will be referred to as a negative electrode.

[Sulfide-based inorganic solid electrolyte material]
First, the sulfide-based inorganic solid electrolyte material of this embodiment will be described.
The sulfide-based inorganic solid electrolyte material of the present embodiment is a sulfide-based inorganic solid electrolyte material having a particle diameter d ₅₀ of 0.1 μm or more and 100 μm or less when the cumulative frequency is 50% in a volume-based cumulative frequency distribution curve measured using a laser diffraction/scattering particle size distribution measuring device, and having an adhesion area of 10% or less measured according to the following (method).

(method)
(1) An SUS304 plate having an arithmetic mean roughness Ra of 0.017 μm or more and 0.023 μm or less, a maximum height Rz of 0.14 μm or more and 0.18 μm or less, and a ten-point mean roughness Rzjis of 0.12 μm or more and 0.16 μm or less, measured in accordance with JIS B 0601 (2013), and measuring 8 cm in length and 9 cm in width, is placed so that the vertical side is tangent to the horizontal plane and is inclined at an angle of 45° to the horizontal plane.
(2) Using a sieve with 250 μm openings, 10 g of the sulfide-based inorganic solid electrolyte material is sieved onto the SUS304 plate from a height of 10 cm from the horizontal surface so that the sulfide-based inorganic solid electrolyte material covers the entire SUS304 plate.
(3) A 47 g zirconia ball is dropped three times from a height of 5 cm from the upper end of the SUS304 plate so as to hit only the upper end of the SUS304 plate and not the surface of the SUS304 plate to which the sulfide-based inorganic solid electrolyte material is attached.
(4) After the impact, the area of the surface of the SUS304 plate to which the sulfide-based inorganic solid electrolyte material is attached is measured, and the ratio (attached area) to the area of one side of the SUS304 plate is calculated.

Examples of raw materials for sulfide-based inorganic solid electrolyte materials include _P2S5 , _Li2S , and _Li3N . For example _{, P2S5 is} a highly reactive and unstable ionic crystal powder, and is therefore crystallized and stabilized by vitrifying it together with _Li2S through a process such as mechanical milling, followed by heat treatment. The crystallinity of this stabilized sulfide-based inorganic solid electrolyte material affects the lithium ion conductivity of a solid electrolyte film obtained using the sulfide-based inorganic solid electrolyte material. In this case, if the vitrification of the sulfide-based inorganic solid electrolyte material through mechanical milling or the like is insufficient and the desired crystalline phase is not produced during heat treatment, the lithium ion conductivity of the resulting solid electrolyte film will be reduced.
Furthermore, sulfide-based inorganic solid electrolyte materials produced using conventional mechanical milling methods can have variations in lithium ion conductivity between production batches due to insufficient reacted sulfide-based inorganic solid electrolyte material being mixed into the sulfide-based inorganic solid electrolyte material recovered from the production equipment.

According to the study by the present inventors, it is possible to prepare a sulfide-based inorganic solid electrolyte material so that the adhesion area of the sulfide-based inorganic solid electrolyte material to the SUS304 plate is 10% or less, that is, to set the vertical side as a tangent to the horizontal plane and inclined at 45° with respect to the horizontal plane, as specified in JIS B The present inventors have found that by appropriately selecting production conditions and formulations such that the adhesion area when 10 g of a sulfide-based inorganic solid electrolyte material is sieved onto an SUS304 plate having an arithmetic mean roughness Ra of 0.017 μm to 0.023 μm, a maximum height Rz of 0.14 μm to 0.18 μm, and a ten-point mean roughness Rzjis of 0.12 μm to 0.16 μm, as measured in accordance with ISO 140601 (2013), using a sieve with 250 μm openings from a height of 10 cm from the horizontal surface, and then dropping 47 g of zirconia balls onto the upper end of the SUS304 plate from a height of 5 cm from the upper end of the SUS304 plate to apply impact three times, the variation in lithium ion conductivity between production batches can be reduced while maintaining conventional handleability and lithium ion conductivity, and a sulfide-based inorganic solid electrolyte material having high lithium ion conductivity can be stably obtained, thereby completing the present invention.
Although the reason for this is unclear, a small adhesion area to the SUS304 plate can be interpreted as a small amount of unstable and highly reactive unreacted raw material composition. As a result, it is believed that a sulfide-based inorganic solid electrolyte material can be provided that maintains the conventional handleability and lithium ion conductivity while exhibiting little variation in lithium ion conductivity between production batches.

Here, in the sulfide-based inorganic solid electrolyte material according to this embodiment, the upper limit of the adhesion area measured according to the above (method) is 10% or less, more preferably 8% or less, and even more preferably 5% or less. By having the adhesion area be the above upper limit or less, it is possible to further reduce the amount of unreacted raw material composition in the sulfide-based inorganic solid electrolyte material.
The lower limit of the adhesion area is not particularly limited, but is, for example, 0% or more.

In order for the sulfide-based inorganic solid electrolyte material according to this embodiment to have the above-described adhesion area,
It is preferable to appropriately select the following two points: (i) raw material blending ratio of the sulfide-based inorganic solid electrolyte material, and (ii) manufacturing method. Here, as for (i) raw material blending ratio, it is preferable that the molar ratio of the Li content to the P content (Li/P) and the molar ratio of the S content to the P content (S/P) in the sulfide-based inorganic solid electrolyte material, which will be described later, are within the ranges described later.
In addition, in the (ii) manufacturing method, it is preferable to use an apparatus whose inner wall surface is a smooth surface with little surface roughness. An example of such an apparatus whose inner wall surface is a smooth surface is apparatus 10 described below.

The sulfide-based inorganic solid electrolyte material according to this embodiment has a particle diameter d 50 at a cumulative frequency of 50% in a volume-based cumulative frequency distribution curve measured using a laser diffraction/scattering particle size distribution measuring device of _0.1 μm or more and 100 μm or less, preferably 2 μm or more and 50 μm or less, and more preferably 3 μm or more and 25 μm or less.
By setting the particle diameter _d50 of the sulfide-based inorganic solid electrolyte material within the above range, good handling properties can be maintained and the lithium ion conductivity of the resulting solid electrolyte membrane can be further improved.

The sulfide-based inorganic solid electrolyte material according to this embodiment is preferably a powdered sulfide-based inorganic solid electrolyte material containing Li, P, and S as constituent elements.

In the sulfide-based inorganic solid electrolyte material according to this embodiment, from the viewpoint of further improving lithium ion conductivity, electrochemical stability, stability in moisture and air, ease of handling, and the like, the molar ratio of the Li content to the P content in the sulfide-based inorganic solid electrolyte material (Li/P) is preferably 1.0 or more and 10.0 or less, more preferably 1.5 or more and 5.0 or less, even more preferably 1.8 or more and 4.5 or less, still more preferably 2.0 or more and 4.4 or less, and particularly preferably 2.3 or more and 4.3 or less.
The molar ratio of the S content to the P content (S/P) is preferably 1.0 or more and 10.0 or less, more preferably 2.5 or more and 6.0 or less, even more preferably 3.0 or more and 5.0 or less, still more preferably 3.5 or more and 4.8 or less, and particularly preferably 3.7 or more and 4.5 or less.
Here, the contents of Li, P, and S in the solid electrolyte material of this embodiment can be determined by, for example, ICP emission spectroscopy.

In the sulfide-based inorganic solid electrolyte material according to this embodiment, the lower limit of the lithium ion conductivity of the sulfide-based inorganic solid electrolyte material, as measured by an AC impedance method under the measurement conditions of 27.0°C, an applied voltage of 10 mV, and a measurement frequency range of 0.1 Hz to 7 MHz, is preferably 1.0 × 10 ^-4 S·cm ^-1 or more, more preferably 2.2 × 10 ^-4 S·cm ^-1 or more, still more preferably 2.5 × 10 ^-4 S·cm ^-1 or more, and particularly preferably 2.8 × 10 ^-4 S·cm ^-1 or more.
When the lithium ion conductivity of the sulfide-based inorganic solid electrolyte material according to this embodiment is equal to or higher than the above lower limit, an all-solid-state lithium ion battery with even more excellent battery characteristics can be obtained.
The upper limit of the lithium ion conductivity of the sulfide-based inorganic solid electrolyte material is not particularly limited, but is, for example, 3.0×10 ⁻³ S·cm ⁻¹ or less.

The sulfide-based inorganic solid electrolyte material according to this embodiment may be, for example, in the form of particles.

The sulfide-based inorganic solid electrolyte material according to this embodiment is used, for example, in a solid electrolyte layer that constitutes an all-solid-state lithium ion battery.
An example of an all-solid-state lithium ion battery using the sulfide-based inorganic solid electrolyte material according to this embodiment is one in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are stacked in this order, where the solid electrolyte layer is made of the sulfide-based inorganic solid electrolyte material.

[Method for producing sulfide-based inorganic solid electrolyte material]
Next, a method for producing the sulfide-based inorganic solid electrolyte material according to this embodiment will be described.
The method for producing a sulfide-based inorganic solid electrolyte material according to this embodiment is different from conventional methods for producing sulfide-based inorganic solid electrolyte materials. For the sulfide-based inorganic solid electrolyte material according to this embodiment, which has an adhesion area to the SUS304 plate within the above range, it is important to highly control the production conditions, such as the composition ratio of the sulfide-based inorganic solid electrolyte material and the vitrification of the inorganic composition as a raw material.
More specifically, the sulfide-based inorganic solid electrolyte material according to this embodiment can be obtained by a production method including the following steps (A) and (B): The production method for the sulfide-based inorganic solid electrolyte material according to this embodiment may further include the following step (C).

Step (A): A step of preparing an inorganic composition containing two or more inorganic compounds as raw materials. Step (B): A step of mechanically treating the inorganic composition to chemically react the inorganic compounds as raw materials and vitrify the inorganic composition. Step (C): A step of pulverizing, classifying, or granulating the obtained sulfide-based inorganic solid electrolyte material.

Each process is explained in detail below.

(Step (A) of Preparing Inorganic Composition)
First, an inorganic composition containing two or more inorganic compounds as raw materials is prepared.
The inorganic compounds used are two or more compounds that chemically react with each other by mechanical treatment to produce a sulfide-based inorganic solid electrolyte material containing, as constituent elements, Li, P, and S. These inorganic compounds can be appropriately selected depending on the sulfide-based inorganic solid electrolyte material to be produced, and examples that can be used include lithium sulfide, phosphorus sulfide, and lithium nitride.

The inorganic composition can be obtained, for example, by mixing two or more inorganic compounds as raw materials in a predetermined molar ratio so that the sulfide-based inorganic solid electrolyte material to be produced has a desired composition ratio.
The method for mixing two or more inorganic compounds is not particularly limited as long as it is a mixing method that can uniformly mix the inorganic compounds. For example, mixing can be performed using a mortar, a ball mill, a bead mill, a vibration mill, an impact mill, a mixer (a pug mixer, a ribbon mixer, a tumbler mixer, a drum mixer, a V-type mixer, etc.), an airflow mill, etc.
The mixing conditions, such as the stirring speed, treatment time, temperature, reaction pressure, and gravitational acceleration applied to the mixture when mixing the inorganic compounds, can be appropriately determined depending on the amount of the mixture to be treated.

The lithium sulfide used as a raw material is not particularly limited, and commercially available lithium sulfide may be used, or lithium sulfide obtained by, for example, reacting lithium hydroxide with hydrogen sulfide may be used. From the viewpoint of obtaining a high-purity sulfide-based inorganic solid electrolyte material and from the viewpoint of suppressing side reactions, it is preferable to use lithium sulfide with few impurities.
In this embodiment, lithium sulfide also includes lithium polysulfide.

The phosphorus sulfide used as a raw material is not particularly limited _{, and} commercially available phosphorus sulfides (e.g., _P2S5 , _P4S3 , _P4S7 , _P4S5 , etc.) can be used. From the viewpoint of obtaining a high-purity sulfide-based inorganic solid electrolyte material and from the viewpoint _of suppressing _side reactions, it is preferable to use phosphorus sulfide with few impurities. Furthermore, instead of phosphorus sulfide, elemental phosphorus (P) and elemental sulfur (S) can also be used in a corresponding molar ratio. The elemental phosphorus (P) and elemental sulfur (S) can be used without particular limitation as long as they are industrially produced and commercially available.

Lithium nitride may be used as the inorganic compound raw material. Here, since nitrogen in lithium nitride is discharged into the system as _N2 , by using lithium nitride as the inorganic compound raw material, it becomes possible to increase only the Li composition in a sulfide-based inorganic solid electrolyte material containing Li, P, and S as constituent elements.
The lithium nitride of the present embodiment is not particularly limited, and may be commercially available lithium nitride (e.g., Li ₃ N, etc.), or may be lithium nitride obtained by reacting metallic lithium (e.g., Li foil) with nitrogen gas. From the viewpoint of obtaining a high-purity solid electrolyte material and suppressing side reactions, it is preferable to use lithium nitride with few impurities.

(Step (B) of vitrifying the inorganic composition)
Next, the inorganic composition is mechanically treated to cause a chemical reaction between the inorganic compounds that are raw materials, thereby vitrifying the inorganic composition.
Here, the mechanical treatment is a process in which two or more types of inorganic compounds, which are raw materials, are mechanically collided with each other to cause a chemical reaction and thereby vitrify the inorganic composition, and examples of such a process include mechanochemical treatment.

Mechanochemical processing is a method of vitrifying a mixture by applying mechanical energy such as shear force, impact force, or centrifugal force. Examples of equipment for vitrification through mechanochemical processing include grinding and dispersing machines such as ball mills, bead mills, vibration mills, turbo mills, mechanofusion machines, disc mills, and roll mills, as well as impact crushing devices that combine rotation, extrusion, and impact mechanisms, such as jackhammers, vibration drills, and impact drivers. Among these, from the perspective of solving the problems of the present application, it is preferable to use device 10, described below, as an impact crushing device that combines rotation, extrusion, and impact mechanisms.

The mechanochemical treatment is preferably carried out in an inert atmosphere, which can prevent the inorganic composition from reacting with water vapor, oxygen, etc.
Furthermore, "under an inert atmosphere" refers to a vacuum atmosphere or an inert gas atmosphere. In the inert atmosphere, the dew point is preferably -50°C or lower, more preferably -60°C or lower, to avoid contact with moisture. The inert gas atmosphere refers to an atmosphere of an inert gas such as argon gas, helium gas, or nitrogen gas. The higher the purity of these inert gases, the more preferable they are to prevent impurities from being mixed into the product. The method for introducing the inert gas into the mixed system is not particularly limited as long as the mixed system is filled with an inert gas atmosphere, but examples include a method of purging the inert gas and a method of continuously introducing a constant amount of inert gas.

Also, when vitrifying the inorganic composition, an aprotic organic solvent such as hexane, toluene, or xylene may be added, and the raw materials may be dispersed in the solvent before vitrification.

The mixing conditions for vitrifying the inorganic composition, such as the rotation speed, treatment time, temperature, reaction pressure, and gravitational acceleration applied to the inorganic composition, can be appropriately determined depending on the type and treatment amount of the inorganic composition. Generally, the faster the rotation speed, the faster the glass production rate, and the longer the treatment time, the higher the conversion rate to glass.
Generally, when X-ray diffraction analysis is performed using CuKα radiation as a radiation source, if the diffraction peak of the inorganic composition disappears or decreases, it can be determined that the inorganic composition has been vitrified and a desired sulfide-based inorganic solid electrolyte material has been obtained.

(Device 10)
Here, an apparatus 10 preferably used for producing such a sulfide-based inorganic solid electrolyte material will be described with reference to the drawings.

Figure 1 is a diagram showing an apparatus 10 for producing a sulfide-based inorganic solid electrolyte material according to this embodiment. Figure 2 is a top view of the turntable 212 and multiple balls 214 of the grinding section 200 shown in Figure 1. Figure 3 is a cross-sectional view taken along the line A-A' in Figure 2. The apparatus 10 produces an inorganic material (A) from multiple inorganic compounds (A1). In Figure 1, the upward direction in Figure 1 corresponds to the upward direction in the vertical direction, and the downward direction in Figure 1 corresponds to the downward direction in the vertical direction. For ease of explanation, the pressing section 216 is not shown in Figure 2. The black arrows in Figure 3 indicate the flow of multiple inorganic compounds (A1). The white arrows in Figure 3 indicate the flow of an inert gas.

An overview of the apparatus 10 will be described using Figure 1. The apparatus 10 includes a blower 100, a pulverizer 200, a first recovery unit 300, and a system S. The blower 100 supplies an inert gas. The pulverizer 200 repeatedly vitrifies a plurality of inorganic compounds (A1) using mechanical energy and then blows the vitrified inorganic compounds (A1) upward with the inert gas supplied from the blower 100. At least a portion of the inorganic compounds (A1) blown upward by the inert gas enters the first recovery unit 300. The first recovery unit 300 returns the at least a portion of the inorganic compounds (A1) toward the pulverizer 200. The system S (e.g., piping Pa, buffer tank 110, piping Pb, piping Pc, and piping Pi, which will be described later) circulates the inert gas from the blower 100 to the blower 100 via the pulverizer 200 and the first recovery unit 300.

In this case, by making the inner wall surface of the pulverization section 200 a smooth surface with a small arithmetic mean roughness Ra, it is possible to obtain a sulfide-based inorganic solid electrolyte material with an adhesion area of 10% or less obtained by the above-mentioned (method).
The reason for this is not clear, but it is thought that by making the inner wall surface of the pulverizing section 200 a smooth surface with a small arithmetic mean roughness Ra, adhesion and deposition of the unreacted raw material composition and sulfide-based inorganic solid electrolyte material to the inner wall surface of the apparatus is prevented, making it easier to introduce the unreacted raw material composition and sulfide-based inorganic solid electrolyte material into the pulverizing section 200. As a result, it is thought that the mechanochemical treatment of the unreacted raw material composition and sulfide-based inorganic solid electrolyte material progresses more easily, making it possible to prevent the raw material composition from being recovered in an unreacted state.
Specifically, the upper limit of the arithmetic mean roughness Ra of the inner wall surface of the crushing section 200 measured in accordance with JIS B 0601 (2013) is preferably 0.02 μm, more preferably 0.015 μm, even more preferably 0.01 μm, and particularly preferably 0.005 μm.
The lower limit of the arithmetic mean roughness Ra of the inner wall surface of the crushing section 200 is not particularly limited, but is, for example, 0 μm or more, 0.001 μm or more, or 0.003 μm or more.

In order to reduce the arithmetic mean roughness Ra of the device's inner wall surface, a known polishing process can be performed on the surface of the metal plate used for the device's inner wall surface. An example of a known polishing process is buffing.

In the apparatus 10, the upper limit of the maximum height Rz of the inner wall surface of the pulverizing section 200 measured in accordance with JIS B 0601 (2013) is preferably 0.16 μm, more preferably 0.13 μm, even more preferably 0.10 μm, and particularly preferably 0.05 μm. By setting the maximum height Rz of the inner wall surface of the pulverizing section 200 to the above upper limit or less, it is possible to further reduce the variation in lithium ion conductivity between production batches of the obtained sulfide-based inorganic solid electrolyte material.
The lower limit of the maximum height Rz of the inner wall surface of the crushing section 200 is not particularly limited, but is, for example, 0 μm or more, 0.01 μm or more, or 0.03 μm or more.

In the apparatus 10, the upper limit of the ten-point mean roughness Rzjis of the inner wall surface of the pulverizing section 200 measured in accordance with JIS B 0601 (2013) is preferably 0.14 μm, more preferably 0.10 μm, even more preferably 0.07 μm, and particularly preferably 0.04 μm. By setting the ten-point mean roughness Rzjis of the inner wall surface of the pulverizing section 200 to the above upper limit or less, it is possible to further reduce the variation in lithium ion conductivity between production batches of the obtained sulfide-based inorganic solid electrolyte material.
The lower limit of the ten-point average roughness Rzjis of the inner wall surface of the crushing section 200 is not particularly limited, but is, for example, 0 μm or more, 0.01 μm or more, or 0.03 μm or more.

The structure of the device 10 is explained in more detail below using Figure 1.

The device 10 includes a blower section 100, a buffer tank 110, a pulverizer section 200, a first recovery section 300, a first storage section 310, a second recovery section 400, a second storage section 410, a pressure reduction section 500, a pipe Pa, multiple pipes Pb (fifth pipe), a pipe Pc (second pipe), a pipe Pd (sixth pipe), a pipe Pe (first pipe), a pipe Pf (third pipe), a pipe Pg, a pipe Ph (fourth pipe), a pipe Pi, a pipe Pj, a pipe Pk, a pipe Pl, a pipe Pm, a pipe Pn, a pipe Po, a valve Va1, and multiple valves Vb. 1 (fifth valve), valve Vc1, valve Vc2 (second valve), valve Vc3, valve Vd1 (sixth valve), valve Ve1 (first valve), valve Ve2, valve Vf1 (third valve), valve Vg1, valve Vh1, valve Vh2, valve Vi1, valve Vi2, valve Vj1, valve Vk1, valve Vl1, valve Vm1, valve Vn1, valve Vo1, line Le (first line), line Lh (second line), and exhaust duct D.

Pipe Pa connects the gas outlet 104 of the blower 100 and the gas inlet 112 of the buffer tank 110. Valve Va1 is provided on pipe Pa.

Each of the multiple pipes Pb is connected to each of the multiple gas outlets 114 of the buffer tank 110 and each of the multiple gas inlets 202 of the pulverization section 200. Each of the multiple valves Vb1 is provided on each of the multiple pipes Pb. In one example, when viewed from above the turntable 212 of the pulverization section 200 (details will be described later), the multiple pipes Pb are arranged around the turntable 212, and more specifically, are arranged rotationally symmetrically with respect to the center of the turntable 212 (rotation axis R, described later).

Pipe Pc connects the material discharge pipe 206 of the pulverizing section 200 and the suction port 302 of the first recovery section 300. Valves Vc1, Vc2, and Vc3 are provided on pipe Pc and are arranged in this order from the material discharge pipe 206 of the pulverizing section 200 to the suction port 302 of the first recovery section 300.

Pipe Pd is connected to the material supply pipe 204 of the grinding section 200 and the material discharge port 304 of the first recovery section 300. Valve Vd1 is provided on pipe Pd.

Pipe Pe connects the first storage unit 310 and the material supply port 308 of the first recovery unit 300. Valves Ve1 and Ve2 are provided on pipe Pe, and are arranged in this order from the first storage unit 310 to the material supply port 308 of the first recovery unit 300. Valve Ve1 and valve Ve2 are also detachably attached to pipe Pe along with the first storage unit 310. In other words, when valve Ve1 is removed from pipe Pe, the first storage unit 310 and valve Ve1 can be integrated. Pipe Pe is also connected to line Le between valves Ve1 and Ve2. The interior of pipe Pe can be evacuated or replaced with an inert gas via line Le. In other words, line Le can reduce the pressure inside pipe Pe and introduce an inert gas into pipe Pe.

The pipe Pf communicates with the portion of the pipe Pc located between the valves Vc1 and Vc2 (i.e., between the crushing section 200 and the valve Vc2) and with the suction port 402 of the second recovery section 400. The valve Vf1 is provided on the pipe Pf.

Pipe Pg is connected to the portion of pipe Pc located between valves Vc2 and Vc3 and to the gas exhaust pipe 406 of the second recovery section 400. Valve Vg1 is provided on pipe Pg.

The pipe Ph connects the second storage unit 410 and the material discharge port 404 of the second recovery unit 400. Valves Vh1 and Vh2 are provided on the pipe Ph, and are arranged in this order from the second storage unit 410 to the material discharge port 404 of the second recovery unit 400. Furthermore, the pipe Ph is connected to a line Lh between valves Vh1 and Vh2. The inside of the pipe Ph can be evacuated or replaced with an inert gas via the line Lh. In other words, the line Lh can reduce the pressure inside the pipe Ph and introduce an inert gas into the pipe Ph.

Pipe Pi connects the gas exhaust port 306 of the first recovery section 300 and the gas inlet 102 of the blower section 100. Valves Vi1 and Vi2 are provided on pipe Pi, and are arranged in this order from the gas exhaust port 306 of the first recovery section 300 to the gas inlet 102 of the blower section 100.

The pipe Pj is connected to a portion of the pipe Pi located between the gas outlet 306 of the first recovery section 300 and the valve Vi1, and to a portion of the pipe Pi located between the gas inlet 102 of the blower section 100 and the valve Vi2. The valve Vj1 is provided on the pipe Pj.

The pipe Pk is connected to the adjustment port 116 of the buffer tank 110 and the exhaust duct D. The valve Vk1 is provided on the pipe Pk.

Pipe Pl connects the gas exhaust port 208 of the grinding section 200 and the pressure reduction section 500. Valve Vl1 is provided on pipe Pl.

Pipe Pm is connected to pressure reduction section 500 and exhaust duct D. Valve Vm1 is provided on pipe Pm.

Pipe Pn is connected to the portion of pipe Pl located between the gas exhaust port 208 of the grinding section 200 and valve Vl1, and to exhaust duct D. Valve Vn1 is provided on pipe Pn.

Pipe Po branches off from pipe Pi and leads to exhaust duct D. Specifically, pipe Pi has a portion that connects to the end of pipe Pj located between valve Vi2 and the gas inlet 102 of the blower 100. Pipe Po leads to the portion of pipe Pi located between that portion of pipe Pi and the gas inlet 102 of the blower 100, and to exhaust duct D. Valve Vo1 is provided on pipe Po.

The blower 100 draws in gas from the pipe Pj through the gas inlet 102 of the blower 100. The blower 100 also discharges the gas drawn in through the gas inlet 102 of the blower 100 from the gas outlet 104 of the blower 100. In this way, the blower 100 sends gas to the buffer tank 110 via the pipe Pa. The rotation speed of the motor of the blower 100 can be changed by the inverter 106, and the flow rate of gas sent from the blower 100 can be changed as desired depending on the rotation speed of the motor.

Gas sent from the blower section 100 via piping Pa enters the gas inlet 112 of the buffer tank 110. The gas that enters the buffer tank 110 passes through multiple gas outlets 114 of the buffer tank 110 and is sent to the grinding section 200 via multiple piping Pb. The gas pressure inside the buffer tank 110 is regulated by valve Vk1.

Gas sent from the buffer tank 110 via multiple pipes Pb enters the multiple gas inlets 202 of the pulverizing section 200. Material sent from the first storage section 310 via pipe Pe, the first recovery section 300, and pipe Pd enters the material supply pipe 204 of the pulverizing section 200. At least a portion of the material and at least a portion of the gas inside the pulverizing section 200 are discharged from the material discharge pipe 206 of the pulverizing section 200. The pressure inside the pulverizing section 200 can be reduced by the pressure reduction section 500. In addition, gas inside the pulverizing section 200 can be discharged to the exhaust duct D via pipe Pn.

The first recovery unit 300 sucks in the material and gas in the pipe Pc through the suction port 302 of the first recovery unit 300. The first recovery unit 300 also discharges the material sucked in through the suction port 302 of the first recovery unit 300 from the material discharge port 304 of the first recovery unit 300. In this way, the first recovery unit 300 sends the material to the grinding unit 200 via the pipe Pd. The first recovery unit 300 also discharges the gas sucked in through the suction port 302 of the first recovery unit 300 from the gas discharge port 306 of the first recovery unit 300. In this way, the first recovery unit 300 sends the gas to the blower unit 100 via the pipe Pi. The first recovery unit 300 is, for example, a dust collector.

The second recovery unit 400 sucks in the material and gas in the pipes Pc and Pf through the suction port 402 of the second recovery unit 400. The second recovery unit 400 also discharges the material sucked in through the suction port 402 of the second recovery unit 400 from the material discharge port 404 of the second recovery unit 400. In this way, the second recovery unit 400 sends the material to the second storage unit 410 via the pipe Ph. The second recovery unit 400 also discharges the gas sucked in through the suction port 402 of the second recovery unit 400 from the gas discharge pipe 406 of the second recovery unit 400. The second recovery unit 400 is, for example, a cyclone dust collector.

Here, in the device 10, it is preferable that the inner wall surfaces of the device in the portion through which the powder can pass are smooth surfaces with a small arithmetic mean roughness. By adopting the above configuration, it is possible to further reduce the variation in lithium ion conductivity for each production batch of the obtained sulfide-based inorganic solid electrolyte material. Note that, examples of the portion through which the powder can pass include the first recovery section, the second recovery section, the first storage section, the second storage section, the first pipe, the second pipe, the third pipe, the fourth pipe, the fifth pipe, and the sixth pipe.
Specifically, the upper limit of the arithmetic mean roughness Ra of the inner wall surface of the apparatus in one or more parts selected from the first recovery section, the second recovery section, the first storage section, the second storage section, the first pipe, the second pipe, the third pipe, the fourth pipe, the fifth pipe, and the sixth pipe, as measured according to JIS B 0601 (2013), is preferably 0.02 μm, more preferably 0.015 μm, even more preferably 0.01 μm, and particularly preferably 0.005 μm. By setting the arithmetic mean roughness Ra to the upper limit or less, it is possible to further reduce the variation in lithium ion conductivity between production batches of the obtained sulfide-based inorganic solid electrolyte material.
The lower limit of the arithmetic mean roughness Ra is not particularly limited, but is, for example, 0 μm or more, 0.001 μm or more, or 0.003 μm or more.

In the apparatus 10, the upper limit of the maximum height Rz measured according to JIS B 0601 (2013) of the inner wall surface of the apparatus in one or more parts selected from the first recovery section, the second recovery section, the first storage section, the second storage section, the first pipe, the second pipe, the third pipe, the fourth pipe, the fifth pipe, and the sixth pipe is preferably 0.16 μm, more preferably 0.13 μm, even more preferably 0.10 μm, and particularly preferably 0.05 μm. By setting the maximum height Rz to the upper limit or less, it is possible to further reduce variation in lithium ion conductivity between production batches of the obtained sulfide-based inorganic solid electrolyte material.
The lower limit of the maximum height Rz is not particularly limited, but is, for example, 0 μm or more, 0.01 μm or more, or 0.03 μm or more.

In the apparatus 10, the upper limit of the ten-point average roughness Rzjis measured according to JIS B 0601 (2013) of the inner wall surface of the apparatus in one or more parts selected from the first recovery section, the second recovery section, the first storage section, the second storage section, the first pipe, the second pipe, the third pipe, the fourth pipe, the fifth pipe, and the sixth pipe is preferably 0.14 μm, more preferably 0.10 μm, even more preferably 0.07 μm, and particularly preferably 0.04 μm. By setting the ten-point average roughness Rzjis to the upper limit or less, it is possible to further reduce variation in lithium ion conductivity between production batches of the obtained sulfide-based inorganic solid electrolyte material.
The lower limit of the ten-point average roughness Rzjis is not particularly limited, but is, for example, 0 μm or more, 0.01 μm or more, or 0.03 μm or more.

Next, the structure of the crushing section 200 will be explained using Figures 2 and 3.

The crushing section 200 has a rotating table 212, a plurality of balls 214, and a pressing section 216. In the example shown in Figure 2, the number of balls 214 is seven. However, the number of balls 214 is not limited to the example shown in Figure 2.

The turntable 212 is rotatable around a rotation axis R. The rotation axis R of the turntable 212 passes through the center of the turntable 212 along the height direction (thickness direction) of the turntable 212. The height direction (thickness direction) of the turntable 212 is aligned with the vertical direction. The multiple balls 214 are arranged around the rotation axis R of the turntable 212, and more specifically, are arranged rotationally symmetrically with respect to the rotation axis R. The multiple balls 214 rotate with the rotation of the turntable 212. Each of the multiple balls 214 is rotatable around a rotation axis R1 that rotates with the rotation of the turntable 212. The rotation axis R1 of each ball 214 passes through the center of the ball 214 along the height direction (thickness direction) of the ball 214. The height direction (thickness direction) of the ball 214 is aligned with the vertical direction. The pressing unit 216 presses the multiple balls 214 toward the turntable 212 from the opposite side of the turntable 212.

Next, an example of a method for producing inorganic material (A) from multiple types of inorganic compounds (A1) using apparatus 10 will be described using Figures 1 to 4.

Valves Ve1 and Ve2 are closed, and multiple inorganic compounds (A1) are stored in the first storage unit 310. Specifically, first, the first storage unit 310 and valve Ve1 are removed from the pipe Pe. Next, multiple inorganic compounds (A1) are stored in the first storage unit 310. The multiple inorganic compounds (A1) are stored in an inert gas-controlled atmosphere (e.g., in a glove box). Next, with valve Ve1 closed, the first storage unit 310 and valve Ve1 are attached to the pipe Pe. In this case, even if the first storage unit 310 and valve Ve1 are exposed to the atmosphere, the closed valve Ve1 prevents the multiple inorganic compounds (A1) in the first storage unit 310 from being exposed to the atmosphere (air). Furthermore, any atmosphere that enters the pipe Pe when the first storage unit 310 is attached can be replaced with an inert gas via line Le connected to the pipe Pe. This prevents the inorganic compound (A1) from being exposed to the atmosphere (air) as it passes through pipe Pe. Next, valves Ve1, Ve2, and Vd1 are opened to send the multiple inorganic compounds (A1) from the first storage unit 310 to the crushing unit 200 via pipe Pe, first recovery unit 300, and pipe Pd. That is, the first storage unit 310 stores the multiple inorganic compounds (A1) to be supplied to the crushing unit 200.

Furthermore, valves Ve1, Ve2, Vf1, Vg1, Vh1, Vh2, Vj1, Vl1, Vm1, Vn1, and Vo1 are closed, and valves Va1, Vb1, Vc1, Vc2, Vc3, Vd1, Vi1, and Vi2 are opened to supply inert gas to the portion of pipe Pi located between valves Vi1 and Vi2. Next, the blower unit 100 is operated while adjusting the pressure inside the buffer tank 110 with valve Vk1. As a result, system S, i.e., the system from blower unit 100 through pipe Pa, buffer tank 110, pipe Pb, grinding unit 200, pipe Pc, first recovery unit 300, and pipe Pi to blower unit 100, circulates inert gas and is closed from the outside (i.e., system S is not exposed to the atmosphere (air)).

The supply of inert gas to the portion of the pipe Pi located between valves Vi1 and Vi2 may be carried out before or after the supply of multiple types of inorganic compounds (A1) from the first storage unit 310 to the pulverization unit 200, or may be carried out while the multiple types of inorganic compounds (A1) are being supplied from the first storage unit 310 to the pulverization unit 200. Furthermore, the position to which the inert gas is supplied does not have to be the portion of the pipe Pi located between valves Vi1 and Vi2, but may be any portion of the system S. Furthermore, the inert gas may be supplied to multiple portions of the system S (including the portion of the pipe Pi located between valves Vi1 and Vi2).

The inert gas introduced into the apparatus 10 is, for example, nitrogen gas. The nitrogen gas is supplied, for example, from a nitrogen cylinder via a nitrogen purification device. In this example, the impurity concentration (e.g., moisture concentration or oxygen concentration) of the nitrogen gas can be reduced. For example, the moisture concentration of the nitrogen gas can be reduced to 400 ppm or less, preferably 40 ppm or less, and more preferably 2 ppm or less, and the oxygen concentration of the nitrogen gas can be reduced to 400 ppm or less, preferably 40 ppm or less, and more preferably 2 ppm or less. However, the inert gas may be a gas other than nitrogen gas, such as argon gas.

Furthermore, the pulverizing unit 200 is operated. Specifically, the turntable 212 is rotated around the rotation axis R, each ball 214 is rotated around the rotation axis R1, and the pressing unit 216 presses the multiple balls 214 toward the turntable 212. The operation of the pulverizing unit 200 may be initiated before or after the multiple inorganic compounds (A1) are supplied from the first storage unit 310 to the pulverizing unit 200, or may be initiated while the multiple inorganic compounds (A1) are being supplied from the first storage unit 310 to the pulverizing unit 200. The pulverizing unit 200 repeatedly vitrifies the multiple inorganic compounds (A1) using mechanical energy and blows up the vitrified multiple inorganic compounds (A1) using the inert gas sent from the blower unit 100, as follows.

First, as shown by the black arrows extending from the material supply pipe 204 toward the turntable 212 in Figure 3, multiple types of inorganic compounds (A1) supplied from the first container 310 travel through the material supply pipe 204 and reach the center of the turntable 212 or its periphery (rotation axis R and its periphery).

3 , as indicated by the two black arrows extending in both directions from the periphery of the center (rotation axis R) of the turntable 212, the multiple inorganic compounds (A1) move from the center (rotation axis R) of the turntable 212 toward the balls 214 due to centrifugal force generated by the rotation of the turntable 212, and enter the gap between the turntable 212 and the balls 214. The multiple inorganic compounds (A1) that have entered the gap between the turntable 212 and the balls 214 are vitrified by mechanical energy. Specifically, shear stress and compressive stress are applied to the multiple inorganic compounds (A1) that have entered the gap between the turntable 212 and the balls 214 due to the rotation of the balls 214 and the pressing of the balls 214 against the turntable 212 by the pressing unit 216. The multiple inorganic compounds (A1) are vitrified by this shear stress and compressive stress. In other words, the multiple inorganic compounds (A1) are subjected to mechanical milling.

As shown by the two white arrows on either side of the turntable 212, the balls 214, and the pressing unit 216 in Figure 3, a flow of inert gas is generated outside the turntable 212 from below to above the pulverizing unit 200. This flow is caused by inert gas sent from the blower unit 100 via the gas inlet 202 of the pulverizing unit 200. As shown by the two black arrows on either side of the balls 214 and the pressing unit 216 in Figure 3, the vitrified inorganic compounds (A1) are blown upward by the inert gas. At this time, the rotation speed of the motor of the blower unit 100 is kept low by the inverter 106, which keeps the flow rate of inert gas sent from the blower unit 100 to the pulverizing unit 200 low and minimizes the inorganic compounds (A1) from escaping through the material discharge pipe 206.

As shown by the two black arrows extending from the outside of the turntable 212 toward the center of the turntable 212 above the pressing unit 216 in Figure 3, some of the multiple inorganic compounds (A1) blown up by the inert gas move from the outside of the turntable 212 toward the center of the turntable 212 above the pressing unit 216. Similar to the multiple inorganic compounds (A1) supplied from the material supply pipe 204, these multiple inorganic compounds (A1) reach the center of the turntable 212 or its vicinity (rotation axis R and its vicinity). The multiple inorganic compounds (A1) are then subjected to mechanical milling in a manner similar to that described above.

As shown by the two black arrows extending above the pressing unit 216 in FIG. 3 , some of the inorganic compounds (A1) blown up by the inert gas may enter the material discharge pipe 206 without returning to the turntable 212. For example, inorganic compounds (A1) with small particle sizes tend to enter the material discharge pipe 206 without returning to the turntable 212. The inorganic compounds (A1) that enter the material discharge pipe 206 are sent to the first recovery unit 300 via pipe Pc, and from the first recovery unit 300 are sent to the material supply pipe 204 of the milling unit 200 via pipe Pd, returning to the turntable 212. Therefore, even the inorganic compounds (A1) that enter the material discharge pipe 206 can be mechanically milled again by the milling unit 200.

As described above, while mechanical milling is being performed in the milling section 200, system S, i.e., the system extending from the blower section 100 via piping Pa, buffer tank 110, piping Pb, milling section 200, piping Pc, first recovery section 300, and piping Pi to the blower section 100, circulates inert gas and is closed off from the outside. This reduces contact between the multiple inorganic compounds (A1) and the air.

The grinding section 200 mechanically mills the multiple inorganic compounds (A1), vitrifying the multiple inorganic compounds (A1), and producing the inorganic material (A) from the multiple inorganic compounds (A1).

Figure 4 shows a modified example of Figure 3.

The pulverizing unit 200 further includes a cover unit 220. The cover unit 220 is located above the pressing unit 216. As shown by the white arrows extending along the cover unit 220 in FIG. 4 , the cover unit 220 directs the flow of inert gas blowing up the multiple inorganic compounds (A1) toward the center of the pulverizing unit 200 (the rotation axis R of the turntable 212) and below the pulverizing unit 200. In this case, compared to when the cover unit 220 is not provided, the amount of multiple inorganic compounds (A1) blown up by the inert gas and entering the material discharge pipe 206 can be reduced, and the amount of multiple inorganic compounds (A1) blown up by the inert gas and returning to the turntable 212 can be increased. Therefore, the efficiency of mechanical milling in the pulverizing unit 200 can be improved compared to when the cover unit 220 is not provided.

Next, an example of a method for removing inorganic material (A) from the device 10 will be described.

Valve Vc2 is closed, valves Vf1 and Vg1 are opened, and the inverter 106 connected to the motor of the blower unit 100 is controlled to increase the rotation speed of the motor, thereby increasing the flow rate of inert gas sent to the gas inlet 202 of the pulverizer unit 200 (valves Vh1 and Vh2 are closed at this stage). By increasing the flow rate of inert gas sent to the gas inlet 202 of the pulverizer unit 200, the inorganic material (A) blown up by the inert gas within the pulverizer unit 200 is sent into the material discharge pipe 206 with little or no material returning to the turntable 212. The inorganic material (A) sent into the material discharge pipe 206 flows through pipes Pc and Pf into the suction port 402 of the second recovery unit 400. As a result, the inorganic material (A) is recovered by the second recovery unit 400. Next, valves Vh1 and Vh2 are opened. As a result, the inorganic material (A) recovered by the second recovery unit 400 flows into the second storage unit 410 via the pipe Ph. Next, valves Vh1 and Vh2 are closed. Next, the second storage unit 410 is removed from the pipe Ph. In this case, by closing valves Vh1 and Vh2, the interior of the pipe Ph is prevented from being exposed to the atmosphere (air). When the second storage unit 410 is reattached to the pipe Ph, the atmosphere that has entered the pipe Ph can be replaced with an inert gas through line Lh connected to the pipe Ph. This prevents the inorganic material (A) from being exposed to the atmosphere (air) as it passes through the pipe Ph.

Next, an example of the operation of the pressure reduction unit 500 will be described.

The interior of the pulverization unit 200 may be exposed to the atmosphere (gas), for example, when cleaning the internal components of the pulverization unit 200 (e.g., the turntable 212, ball 214, or pressing unit 216). In this case, the pressure inside the pulverization unit 200 can be reduced using the pressure reduction unit 500 to remove the air from inside the pulverization unit 200. For example, the pressure reduction unit 500 can be operated by closing multiple valves Vb1, Vc1, Vd1, and Vn1 and opening valves Vl1 and Vm1.

Sulfide-based inorganic solid electrolyte material produced using such an apparatus can be recovered without adhering to the inner wall surfaces of the apparatus. This reduces the amount of unreacted raw material composition in the sulfide-based inorganic solid electrolyte material, resulting in less variation in lithium ion conductivity between production batches and the production of sulfide-based inorganic solid electrolyte material with excellent stability.

(Pulverizing, classifying, or granulating step (C))
In the method for producing a sulfide-based inorganic solid electrolyte material according to this embodiment, the obtained sulfide-based inorganic solid electrolyte material may further be subjected to a step of pulverizing, classifying, or granulating, if necessary. For example, a sulfide-based inorganic solid electrolyte material having a desired particle size can be obtained by pulverizing the material to obtain fine particles, and then adjusting the particle size by a classification or granulation operation. The pulverizing method is not particularly limited, and known pulverizing methods such as a mixer, airflow pulverizer, mortar, rotary mill, and coffee mill can be used. The classification method is also not particularly limited, and known methods such as a sieve can be used.
The pulverization or classification is preferably carried out in an inert gas atmosphere or a vacuum atmosphere, since this can prevent contact with moisture in the air.

[Solid electrolyte membrane]
Next, the solid electrolyte membrane according to this embodiment will be described.
The solid electrolyte membrane according to this embodiment is a solid electrolyte membrane containing the sulfide-based inorganic solid electrolyte material according to this embodiment described above as a main component.

The solid electrolyte membrane according to this embodiment is used, for example, as a solid electrolyte layer constituting an all-solid-state lithium ion battery.
An example of an all-solid-state lithium ion battery using the solid electrolyte membrane according to this embodiment is one in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are stacked in this order, where the solid electrolyte layer is made of a solid electrolyte membrane.

The average thickness of the solid electrolyte membrane according to this embodiment is preferably 5 μm or more and 500 μm or less, more preferably 10 μm or more and 200 μm or less, and even more preferably 20 μm or more and 100 μm or less. When the average thickness of the solid electrolyte membrane is equal to or greater than the above-mentioned lower limit, chipping of the sulfide-based inorganic solid electrolyte material and the occurrence of cracks on the surface of the solid electrolyte membrane can be further suppressed. Furthermore, when the average thickness of the solid electrolyte membrane is equal to or less than the above-mentioned upper limit, the impedance of the solid electrolyte membrane can be further reduced. As a result, the battery characteristics of the resulting all-solid-state lithium-ion battery can be further improved.

The solid electrolyte membrane according to this embodiment is preferably a pressure-molded body of a powdered sulfide-based inorganic solid electrolyte material. That is, it is preferable to pressurize particulate inorganic solid electrolyte material to form a solid electrolyte membrane having a certain strength due to the anchoring effect between the inorganic solid electrolyte material particles.
By forming the inorganic solid electrolyte into a compact, bonding between the inorganic solid electrolyte materials occurs, and the strength of the resulting solid electrolyte membrane is further increased, which further suppresses chipping of the inorganic solid electrolyte material and cracks on the surface of the inorganic solid electrolyte material.

The content of the sulfide-based inorganic solid electrolyte material according to this embodiment in the solid electrolyte membrane according to this embodiment is preferably 98% by mass or more, more preferably 99% by mass or more, and even more preferably 100% by mass, when the entire solid electrolyte membrane is taken as 100% by mass. This improves contact between the inorganic solid electrolyte materials and reduces the interfacial contact resistance of the solid electrolyte membrane. As a result, the lithium ion conductivity of the solid electrolyte membrane can be further improved. Furthermore, by using such a solid electrolyte membrane with excellent lithium ion conductivity, the battery characteristics of the resulting all-solid-state lithium ion battery can be further improved.

The planar shape of the solid electrolyte membrane is not particularly limited and can be selected appropriately to match the shapes of the electrode layers and current collector layers, but it can be rectangular, for example.

The solid electrolyte membrane according to this embodiment may contain a binder resin, but the content of the binder resin is preferably less than 0.5 mass %, more preferably 0.1 mass % or less, even more preferably 0.05 mass % or less, and even more preferably 0.01 mass % or less, when the entire solid electrolyte membrane is taken as 100 mass %. It is even more preferable that the solid electrolyte membrane according to this embodiment does not substantially contain a binder resin, and most preferably does not contain a binder resin.
This improves the contact between the solid electrolyte materials and reduces the interfacial contact resistance of the solid electrolyte membrane. As a result, the lithium ion conductivity of the solid electrolyte membrane can be further improved. Furthermore, by using such a solid electrolyte membrane with excellent lithium ion conductivity, the battery characteristics of the resulting all-solid-state lithium ion battery can be improved.
The phrase "substantially free of binder resin" means that the binder resin may be contained to an extent that does not impair the effects of the present embodiment. In addition, when an adhesive resin layer is provided between the solid electrolyte layer and the positive electrode layer or the negative electrode layer, the adhesive resin originating from the adhesive resin layer present in the vicinity of the interface between the solid electrolyte layer and the adhesive resin layer is excluded from the "binder resin in the solid electrolyte membrane."

The binder resin mentioned above refers to a binder commonly used in lithium-ion batteries to bind solid electrolyte materials together, and examples include polyvinyl alcohol, polyacrylic acid, carboxymethyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride, styrene-butadiene rubber, and polyimide.

The solid electrolyte membrane according to this embodiment can be obtained, for example, by depositing a powdered sulfide-based inorganic solid electrolyte material in the form of a film on the cavity surface of a mold or on the surface of a substrate, and then pressurizing the sulfide-based inorganic solid electrolyte material deposited in the form of a film.
The method for pressing the sulfide-based inorganic solid electrolyte material is not particularly limited. For example, when the powdered sulfide-based inorganic solid electrolyte material is deposited on the cavity surface of a mold, pressing with a mold and a stamping die can be used; when the powdered sulfide-based inorganic solid electrolyte material is deposited on the surface of a substrate, pressing with a mold and a stamping die, roll pressing, flat plate pressing, etc. can be used.
The pressure to which the sulfide-based inorganic solid electrolyte material is applied is, for example, 10 MPa or more and 500 MPa or less.

If necessary, the sulfide-based inorganic solid electrolyte material deposited in the form of a film may be heated and pressurized. Heating and pressurizing causes fusion and bonding of the sulfide-based inorganic solid electrolyte material to each other, further increasing the strength of the resulting solid electrolyte film. As a result, chipping of the sulfide-based inorganic solid electrolyte material and the occurrence of cracks on the surface of the sulfide-based inorganic solid electrolyte material can be further suppressed.
The temperature to which the sulfide-based inorganic solid electrolyte material is heated is, for example, 40°C or higher and 500°C or lower.

[All-solid-state lithium-ion battery]
Next, an all-solid-state lithium-ion battery 600 according to this embodiment will be described. Fig. 5 is a cross-sectional view schematically showing an example of the structure of the all-solid-state lithium-ion battery 600 according to an embodiment of the present invention. The all-solid-state lithium-ion battery 600 according to this embodiment is a lithium-ion secondary battery, but may also be a lithium-ion primary battery.

The all-solid-state lithium-ion battery 600 according to this embodiment is formed by laminating, in this order, a positive electrode layer 610, a solid electrolyte layer 620, and a negative electrode layer 630. The solid electrolyte layer 620 is formed from the solid electrolyte membrane according to this embodiment.
Moreover, the all-solid-state lithium-ion battery 600 according to the embodiment can also be made into a bipolar lithium-ion battery by stacking two or more unit cells each composed of a positive electrode layer 610, a solid electrolyte layer 620, and a negative electrode layer 630.
The shape of the all-solid-state lithium ion battery 600 is not particularly limited, and may be a cylindrical shape, a coin shape, a square shape, a film shape, or any other shape.

The all-solid-state lithium-ion battery 600 according to this embodiment is manufactured in accordance with a generally known method. For example, it is produced by stacking a positive electrode layer 610, a solid electrolyte layer 620, and a negative electrode layer 630, and forming the stack into a cylindrical, coin-shaped, rectangular, film-shaped, or other arbitrary shape.

The positive electrode layer 610 is not particularly limited, and a positive electrode generally used in all-solid-state lithium-ion batteries can be used. The positive electrode layer 610 is not particularly limited, and can be manufactured according to a generally known method. For example, the positive electrode layer 610 can be obtained by forming a positive electrode active material layer containing a positive electrode active material on a current collector such as aluminum foil.
The thickness and density of the positive electrode active material layer are not particularly limited and can be determined appropriately depending on the intended use of the battery, and can be set in accordance with generally known information.

The positive electrode active material layer contains a positive electrode active material.
The positive electrode active material is not particularly limited, and may be any commonly known positive electrode active material that can be used for the positive electrode layer of an all-solid-state lithium-ion battery. For example, composite oxides such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), solid solution oxides (Li ₂ MnO ₃ -LiMO ₂ (M=Co, Ni, etc.)), lithium-manganese-nickel oxide (LiNi1/3Mn1/3Co1/3O2), and olivine-type lithium phosphate oxide (LiFePO ₄ ); conductive polymers such as polyaniline and polypyrrole; Li ₂ S, CuS, Li-Cu-S compounds, TiS ₂ , FeS, and MoS _{2 .} Examples of the positive electrode active materials that can be used include sulfide-based positive electrode active materials such as Li-Mo-S compounds, Li-Ti-S compounds, and Li-V-S compounds; and materials using sulfur as an active material, such as sulfur-impregnated acetylene black, sulfur-impregnated porous carbon, and mixed powder of sulfur and carbon. These positive electrode active materials may be used alone or in combination of two or more.
Among these, sulfide-based positive electrode active materials are preferred from the viewpoint of having a higher discharge capacity density and having better cycle characteristics, and one or more selected from Li—Mo—S compounds, Li—Ti—S compounds, and Li—V—S compounds are more preferred.

Here, the Li-Mo-S compound contains Li, Mo, and S as constituent elements, and can usually be obtained by mixing and grinding the raw materials molybdenum sulfide and lithium sulfide using a mechanochemical treatment or the like.
In addition, the Li-Ti-S compound contains Li, Ti, and S as constituent elements, and can usually be obtained by mixing and grinding the raw materials titanium sulfide and lithium sulfide using a mechanochemical treatment or the like.
The Li-V-S compound contains Li, V, and S as constituent elements, and can usually be obtained by mixing and grinding the raw materials vanadium sulfide and lithium sulfide using a mechanochemical treatment or the like.

The positive electrode active material layer is not particularly limited, and may contain, as a component other than the positive electrode active material, one or more materials selected from, for example, a solid electrolyte material, a binder, a conductive additive, and the like.
The blending ratio of the various materials in the positive electrode active material layer is not particularly limited and can be determined appropriately depending on the intended use of the battery, and can be set in accordance with generally known information.

The anode layer 630 is not particularly limited, and any anode layer commonly used in all-solid-state lithium-ion batteries can be used. The anode layer 630 is not particularly limited, and can be manufactured according to a commonly known method. For example, the anode layer 630 can be obtained by forming an anode active material layer containing an anode active material on a current collector such as copper foil.
The thickness and density of the negative electrode active material layer are not particularly limited and can be determined appropriately depending on the intended use of the battery, and can be set in accordance with generally known information.

The negative electrode active material layer contains a negative electrode active material.
The negative electrode active material is not particularly limited, and generally known negative electrode active materials that can be used in the negative electrode layer of all-solid-state lithium-ion batteries can be used. Examples include carbonaceous materials such as natural graphite, artificial graphite, resin carbon, carbon fiber, activated carbon, hard carbon, and soft carbon; metal-based materials mainly composed of tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, and aluminum alloys; conductive polymers such as polyacene, polyacetylene, and polypyrrole; metallic lithium; and lithium titanium composite oxides (e.g., Li ₄ Ti ₅ O ₁₂ ). These negative electrode active materials may be used alone or in combination of two or more.

The negative electrode active material layer is not particularly limited, and may contain, as a component other than the negative electrode active material, one or more materials selected from, for example, a solid electrolyte material, a binder, a conductive additive, and the like.
The blending ratio of the various materials in the negative electrode active material layer is not particularly limited and can be determined appropriately depending on the intended use of the battery, and can be set in accordance with generally known information.

The above describes embodiments of the present invention with reference to the drawings, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

The present invention will be explained below using examples and comparative examples, but the present invention is not limited to these.

<Evaluation method>
First, the evaluation methods used in the following examples and comparative examples will be described.

(1) Particle diameter _d50
The particle size distribution of the sulfide-based inorganic solid electrolyte materials obtained in the examples and comparative examples was measured by a laser diffraction scattering method using a laser diffraction scattering particle size distribution analyzer (Malvern Instruments, Mastersizer 3000). From the measurement results, the particle size ( _d50 , particle size) at 50% cumulative volume-based cumulative distribution was determined for each sulfide-based inorganic solid electrolyte material.

(2) Adhesion Area The sulfide-based inorganic solid electrolyte materials obtained in the examples and comparative examples were subjected to the following sieving test. A schematic diagram of sieving a sulfide-based inorganic solid electrolyte material 740 is shown in FIG. 6 , and a schematic diagram of impacting the material with zirconia balls 780 is shown in FIG. 7 . The following description will be made with reference to FIGS. 6 and 7 .
SUS304 having an arithmetic mean roughness Ra of 0.020 μm, a maximum height Rz of 0.16 μm, and a ten-point mean roughness Rzjis of 0.14 μm measured in accordance with JIS B 0601 (2013) was cut to a length of 8 cm and a width of 9 cm to obtain a SUS304 plate 710. The SUS304 plate was then placed on a table so that the installation angle 730 relative to the horizontal plane 720 was 45°. Next, 10 g of the sulfide-based inorganic solid electrolyte material 740 obtained in the examples and comparative examples was sieved off using a sieve 750 with a mesh size of 250 μm from a position where the height 760 from the horizontal plane 720 was 10 cm, so that the sulfide-based inorganic solid electrolyte material 740 was sieved over the entire SUS304 plate 710. Furthermore, a 47 g zirconia ball 780 (manufactured by Nikkato Corporation, spherical, 2.5 cm in diameter) was dropped three times from a position where the height 770 from the top end of the SUS304 plate 710 was 5 cm, so as to hit only the top end of the SUS304 plate 710 and not the surface of the SUS304 plate 710 to which the sulfide-based inorganic solid electrolyte material 740 was attached, thereby applying an impact to the SUS304 plate 710. Finally, the surface of the SUS304 plate 710 to which the sulfide-based inorganic solid electrolyte material 740 was attached after the impact was photographed with a camera, and the photograph was separated into a powder-adhered portion and an unadhered portion using image processing software Paint.net (v4.2.16), and the area of the powder-adhered portion was measured using image analysis software ImageJ (1.52a), and the ratio (adhered area) to the area of one side of the SUS304 plate 710, 72 cm ^2, was calculated.
FIG. 8 shows the appearance of the SUS304 plate after the sieving test using the sulfide-based inorganic solid electrolyte materials of the examples and comparative examples, and the calculation results of the adhesion area.

(3) ICP Optical Emission Spectroscopy Measurement was performed by ICP optical emission spectroscopy using an ICP optical emission spectroscopy analyzer (SPS3000, manufactured by Seiko Instruments Inc.) to determine the mass % of each element in the sulfide-based inorganic solid electrolyte materials obtained in the examples and comparative examples, and based on this, the molar ratio of each element was calculated.

(4) Measurement of Lithium Ion Conductivity Ten batches of each of the sulfide-based inorganic solid electrolyte materials of the Examples and Comparative Examples were prepared, and the lithium ion conductivity of each batch was measured by the AC impedance method.
The lithium ion conductivity was measured using a potentiostat/galvanostat SP-300 manufactured by Biologic Corp. The sample size was φ9.5 mm, thickness 1.3 mm, and the measurement conditions were an applied voltage of 10 mV, a measurement temperature of 27.0°C, a measurement frequency range of 0.1 Hz to 3 MHz, and a Li foil electrode.
Here, as the sample for measuring lithium ion conductivity, a plate-shaped sulfide-based inorganic solid electrolyte material having a thickness of 1.3 mm was used, which was obtained by annealing the powdered sulfide-based inorganic solid electrolyte material obtained in the examples and comparative examples at 290°C for 2 hours using a press machine and then pressing it at 270 MPa for 10 minutes.
Thereafter, the lithium ion conductivity of the sulfide-based inorganic solid electrolyte material measured in each of the Examples and Comparative Examples was averaged over 10 batches, and this average was used as the lithium ion conductivity of the sulfide-based inorganic solid electrolyte material in each of the Examples and Comparative Examples.

(5) Evaluation of Stability of Lithium Ion Conductivity Ten batches of each of the sulfide-based inorganic solid electrolyte materials obtained in the Examples and Comparative Examples were prepared, and the lithium ion conductivity of each batch was measured by the AC impedance method described above in (4).
Next, in each of the Examples and Comparative Examples, the average value of the lithium ion conductivity measured for 10 batches was calculated. Thereafter, the stability of the lithium ion conductivity in the 10 batches was evaluated according to the following three levels.
A: There are no measured values that are 0.85 times or less but 1.15 times or more of the average value. B: There are 1 to 2 batches of measured values that are 0.85 times or less but 1.15 times or more of the average value. C: There are 3 or more batches of measured values that are 0.85 times or less but 1.15 times or more of the average value.

Example 1
A powdered sulfide-based inorganic solid electrolyte material containing Li, P, and S as constituent elements was prepared by the following procedure.
The raw materials used were Li ₂ S (manufactured by Furukawa Co., Ltd., purity 99.9%), P ₂ S ₅ (manufactured by Kanto Chemical Co., Ltd.), and Li ₃ N (manufactured by Furukawa Co., Ltd.).
Next, the raw materials were charged into the apparatus 10 (measured in accordance with JIS B 0601 (2013) for the inner wall surface of the apparatus: Ra: 0.005 μm, Rz: 0.030 μm, Rzjis: 0.026 μm) so as to give a ratio of Li ₂ S:P ₂ S ₅ :Li ₃ N = 71.0:23.7:5.3 (mol %), and mechanical milling was carried out for 70 hours to obtain a sulfide-based inorganic solid electrolyte material.
The obtained sulfide-based inorganic solid electrolyte material was evaluated. The results are shown in Table 1.

<Comparative Example 1>
The raw materials used were the same as those in Example 1.
Next, mechanical milling was performed under the same conditions as in Example 1, except that the apparatus 10 in Example 1 was changed to a conventional apparatus (Ra: 3.0 μm, Rz: 18.8 μm, Rzjis: 17 μm of the apparatus inner wall surface measured in accordance with JIS B 0601 (2013)), to obtain a sulfide-based inorganic solid electrolyte material.
The obtained sulfide-based inorganic solid electrolyte material was evaluated. The results are shown in Table 1.

<Comparative Example 2>
The raw materials used were the same as those in Example 1.
Next, mechanical milling was performed under the same conditions as in Example 1, except that the apparatus 10 in Example 1 was changed to a conventional apparatus (Ra: 1.5 μm, Rz: 7.0 μm, Rzjis: 6.1 μm of the apparatus inner wall surface measured in accordance with JIS B 0601 (2013)), to obtain a sulfide-based inorganic solid electrolyte material.
The obtained sulfide-based inorganic solid electrolyte material was evaluated. The results are shown in Table 1.

<Comparative Example 3>
The raw materials used were the same as those in Example 1.
Next, mechanical milling was performed under the same conditions as in Example 1, except that the apparatus 10 in Example 1 was changed to a conventional apparatus (Ra: 1.0 μm, Rz: 5.7 μm, Rzjis: 4.6 μm of the apparatus inner wall surface measured in accordance with JIS B 0601 (2013)), to obtain a sulfide-based inorganic solid electrolyte material.
The obtained sulfide-based inorganic solid electrolyte material was evaluated. The results are shown in Table 1.

<Comparative Example 4>
The raw materials used were the same as those in Example 1.
Next, mechanical milling was performed under the same conditions as in Example 1, except that the apparatus 10 in Example 1 was changed to a conventional apparatus (Ra: 0.5 μm, Rz: 2.4 μm, Rzjis: 2.1 μm of the apparatus inner wall surface measured in accordance with JIS B 0601 (2013)), to obtain a sulfide-based inorganic solid electrolyte material.
The obtained sulfide-based inorganic solid electrolyte material was evaluated. The results are shown in Table 1.

Comparative Example 5
The raw materials used were the same as those in Example 1.
Next, mechanical milling was performed under the same conditions as in Example 1, except that the apparatus 10 in Example 1 was changed to a conventional apparatus (Ra: 0.3 μm, Rz: 1.6 μm, Rzjis: 1.2 μm of the apparatus inner wall surface measured in accordance with JIS B 0601 (2013)), to obtain a sulfide-based inorganic solid electrolyte material.
The obtained sulfide-based inorganic solid electrolyte material was evaluated. The results are shown in Table 1.

<Comparative Example 6>
The raw materials used were the same as those in Example 1.
Next, mechanical milling was performed under the same conditions as in Example 1, except that the apparatus 10 in Example 1 was changed to a conventional apparatus (Ra: 0.1 μm, Rz: 0.6 μm, Rzjis: 0.5 μm of the apparatus inner wall surface measured in accordance with JIS B 0601 (2013)), to obtain a sulfide-based inorganic solid electrolyte material.
The obtained sulfide-based inorganic solid electrolyte material was evaluated. The results are shown in Table 1.

Comparative Example 7
The raw materials used were the same as those in Example 1.
Next, mechanical milling was performed under the same conditions as in Example 1, except that the apparatus 10 in Example 1 was changed to a conventional apparatus (Ra: 0.05 μm, Rz: 0.29 μm, Rzjis: 0.24 μm of the apparatus inner wall surface measured in accordance with JIS B 0601 (2013)), to obtain a sulfide-based inorganic solid electrolyte material.
The obtained sulfide-based inorganic solid electrolyte material was evaluated. The results are shown in Table 1.

10 Apparatus 100 Blower section 102 Gas inlet 104 Gas outlet 106 Inverter 110 Buffer tank 112 Gas inlet 114 Gas outlet 116 Adjustment port 200 Grinding section 202 Gas inlet 204 Material supply pipe 206 Material discharge pipe 208 Gas discharge port 212 Rotary table 214 Ball 216 Pressing section 220 Cover section 300 First recovery section 302 Suction port 304 Material discharge port 306 Gas discharge port 308 Material supply port 310 First storage section 400 Second recovery section 402 Suction port 404 Material discharge port 406 Gas discharge pipe 410 Second storage section 500 Pressure reduction section 600 All-solid-state lithium ion battery 610 Positive electrode layer 620 Solid electrolyte layer 630 Negative electrode layer 710 SUS340 plate 720 Horizontal surface 730 Installation angle 740 Sulfide-based inorganic solid electrolyte material 750 Sieve 760 Height 770 from horizontal surface 720 Height 780 from the upper end of SUS304 plate 710 Zirconia ball D Exhaust duct Le First line Lh Second line Pa Pipe Pb Fifth pipe Pc Second pipe Pd Sixth pipe Pe First pipe Pf Third pipe Pg Pipe Ph Fourth pipe Pi Pipe Pj Pipe Pk Pipe Pl Pipe Pm Pipe Pn Pipe Po Pipe S System Va1 Valve Vb1 Fifth valve Vc1 Valve Vc2 Second valve Vc3 Valve Vd1 Sixth valve Ve1 First valve Ve2 Valve Vf1 Third valve Vg1 Valve Vh1 Valve Vh2 Valve Vi1 Valve Vi2 Valve Vj1 Valve Vk1 Valve Vl1 Valve Vm1 Valve Vn1 Valve Vo1 valve

Claims (6)

A sulfide-based inorganic solid electrolyte material having a particle diameter _d50 of 0.1 μm or more and 100 μm or less when a cumulative frequency is 50% in a volume-based cumulative frequency distribution curve measured using a laser diffraction/scattering particle size distribution measuring device,
The adhesion area measured according to the following method is 10% or less.
Sulfide-based inorganic solid electrolyte material.
(method)
(1) An SUS304 plate having an arithmetic mean roughness Ra of 0.017 μm or more and 0.023 μm or less, a maximum height Rz of 0.14 μm or more and 0.18 μm or less, and a ten-point mean roughness Rzjis of 0.12 μm or more and 0.16 μm or less, measured in accordance with JIS B 0601 (2013), and measuring 8 cm in length and 9 cm in width, is placed so that the vertical side is tangent to the horizontal plane and is inclined at an angle of 45° to the horizontal plane.
(2) Using a sieve with 250 μm openings, 10 g of the sulfide-based inorganic solid electrolyte material is sieved onto the SUS304 plate from a height of 10 cm from the horizontal surface so that the sulfide-based inorganic solid electrolyte material is applied to the entire SUS304 plate.
(3) A 47 g zirconia ball is dropped three times from a height of 5 cm from the upper end of the SUS304 plate so as to hit only the upper end of the SUS304 plate and not the surface of the SUS304 plate to which the sulfide-based inorganic solid electrolyte material is attached.
(4) After the impact is applied, the area of the surface of the SUS304 plate to which the sulfide-based inorganic solid electrolyte material is attached is measured, and the ratio (attached area) to the area of one side of the SUS304 plate is calculated. The sulfide-based inorganic solid electrolyte material according to claim 1,
A sulfide-based inorganic solid electrolyte material containing Li, P, and S as constituent elements. The sulfide-based inorganic solid electrolyte material according to claim 2,
The sulfide-based inorganic solid electrolyte material has a molar ratio (Li/P) of the Li content to the P content in the sulfide-based inorganic solid electrolyte material of 1.0 or more and 10.0 or less, and a molar ratio (S/P) of the S content to the P content in the sulfide-based inorganic solid electrolyte material of 1.0 or more and 10.0 or less. The sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 3,
A sulfide-based inorganic solid electrolyte material having a lithium ion conductivity of 1.0×10 ⁻⁴ S·cm ⁻¹ or more as measured by an AC impedance method under the measurement conditions of 27.0° C., an applied voltage of 10 mV, and a measurement frequency range of 0.1 Hz to 7 MHz. A solid electrolyte membrane comprising the sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 4. An all-solid-state lithium ion battery including a positive electrode including a positive electrode active material layer, an electrolyte layer, and a negative electrode including a negative electrode active material layer,
An all-solid-state lithium ion battery, wherein at least one of the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer contains the sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 4.