JP2018049732A - Sulfide-based inorganic solid electrolytic material, solid electrolyte film, all-solid lithium ion battery, and method for manufacturing sulfide-based inorganic solid electrolytic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sulfide-based inorganic solid electrolytic material arranged so that a solid electrolyte film suppressed in occurrence of a crack can be obtained with stability.SOLUTION: A sulfide-based inorganic solid electrolytic material of the invention consists of a powdery sulfide-based inorganic solid electrolytic material having lithium ion conductivity and comprising Li, P and S as constituent elements. As to the sulfide-based inorganic solid electrolytic material, an angle of repose measured at 25°C in an argon atmosphere is 57-70°.SELECTED DRAWING: None

Description

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

  Lithium ion batteries are generally used as a power source for small portable devices such as mobile phones and notebook computers. Recently, in addition to small portable devices, lithium ion batteries have begun to be used as power sources for electric vehicles and power storage.

  An electrolyte solution containing a flammable organic solvent is used in a lithium ion battery currently on the market. On the other hand, a lithium ion battery (hereinafter also referred to as an all-solid-state lithium ion battery) in which the electrolyte is changed to a solid electrolyte to make the battery completely solid does not use a flammable organic solvent in the battery. It is considered that the manufacturing cost and productivity are excellent.

  As a solid electrolyte material used for such a solid electrolyte, for example, a sulfide-based inorganic solid electrolyte material is known. Patent Document 1 below describes an example of such a sulfide-based inorganic solid electrolyte material.

Patent Document 1 (Japanese Patent Laid-Open No. 2016-27545) has a peak at a position of 2θ = 29.86 ° ± 1.00 ° in X-ray diffraction measurement using CuKα rays, and Li _{2y + 3} PS ₄ (0. A sulfide-based solid electrolyte material having a composition of 1 ≦ y ≦ 0.175) is described.

JP 2016-27545 A

  According to the study by the present inventors, it is clear that the conventional sulfide-based inorganic solid electrolyte material has insufficient powder binding properties, and the resulting solid electrolyte membrane may be cracked. Became.

  This invention is made | formed in view of the said situation, and provides the sulfide type inorganic solid electrolyte material which can obtain the solid electrolyte membrane in which generation | occurrence | production of the crack was suppressed stably.

The present inventors diligently studied design guidelines for realizing a sulfide-based inorganic solid electrolyte material excellent in lithium ion conductivity and film forming property. As a result, it has been clarified that sulfide-based inorganic solid electrolyte materials having an angle of repose within a specific range are excellent in binding property between powders and can stably obtain a solid electrolyte membrane in which cracks are suppressed. It was.
That is, the present inventors have found that the measure of repose angle is effective as a design guideline for realizing a sulfide-based inorganic solid electrolyte material excellent in lithium ion conductivity and film-forming properties, and has reached the present invention.

That is, according to the present invention,
A powdered sulfide-based inorganic solid electrolyte material having lithium ion conductivity and containing Li, P and S as constituent elements,
There is provided a sulfide-based inorganic solid electrolyte material having an angle of repose of 57 ° or more and 70 ° or less measured at 25 ° C. in an argon atmosphere.

  Moreover, according to this invention, the solid electrolyte membrane which contains the said sulfide type inorganic solid electrolyte material as a main component is provided.

Moreover, according to the present invention,
An all-solid-state lithium ion battery in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are laminated in this order,
There is provided an all solid-state lithium ion battery in which the solid electrolyte layer is composed of the solid electrolyte membrane.

Moreover, according to the present invention,
A production method for producing the sulfide-based inorganic solid electrolyte material,
Provided is a method for producing a sulfide-based inorganic solid electrolyte material including a step of mixing a glass-like sulfide-based inorganic solid electrolyte material (X) and a glass-ceramic sulfide-based inorganic solid electrolyte material (Y). .

  ADVANTAGE OF THE INVENTION According to this invention, the sulfide type inorganic solid electrolyte material which can obtain stably the solid electrolyte membrane in which generation | occurrence | production of the crack was suppressed can be provided.

It is sectional drawing which showed typically an example of the structure of the all-solid-state type lithium ion battery of embodiment which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In all the drawings, similar constituent elements are denoted by common reference numerals, and description thereof is omitted as appropriate. Moreover, the figure is a schematic diagram and does not match the actual dimensional ratio. “A to B” in the numerical range represents A or more and B or less unless otherwise specified.

[Sulfide-based inorganic solid electrolyte materials]
First, the sulfide-based inorganic solid electrolyte material according to the present embodiment will be described.
The sulfide-based inorganic solid electrolyte material according to the present embodiment is a powdered sulfide-based inorganic solid electrolyte material having lithium ion conductivity and containing Li, P, and S as constituent elements.
The repose angle of the sulfide-based inorganic solid electrolyte material according to this embodiment, measured at 25 ° C. under an argon atmosphere, is 57 ° or more, preferably 59 ° or more, more preferably 60 ° or more, and particularly preferably 61. More than °.
In addition, the repose angle of the sulfide-based inorganic solid electrolyte material according to this embodiment, which is measured in an argon atmosphere at 25 ° C., is 70 ° or less, preferably 68 ° or less, and more preferably 66 ° or less.
In the sulfide-based inorganic solid electrolyte material according to this embodiment, by setting the angle of repose within the above range, the binding property between the powders of the sulfide-based inorganic solid electrolyte material is improved, and the solid electrolyte membrane is made thinner. Therefore, it is possible to stably form a solid electrolyte membrane that can be formed wider and more densely and that suppresses the generation of cracks.
Moreover, the handleability of sulfide type inorganic solid electrolyte material can be improved by making an angle of repose into the said upper limit or less.

Here, the angle of repose refers to an angle formed by a conical generatrix obtained by dropping and depositing a powdered sulfide-based inorganic solid electrolyte material on a horizontal plane and the horizontal plane, and is obtained, for example, by an injection method. More specifically, the angle of repose is determined by depositing a powdered sulfide-based inorganic solid electrolyte material on a horizontal plane through a funnel having a discharge hole diameter of 2.63 mm, and measuring the angle between the deposited powder and the horizontal plane. It can ask for. The distance from the discharge hole of the funnel to the horizontal plane is, for example, 25 mm.
The angle of repose can be measured using, for example, a powder rheometer (Furukawa Machine Metal Co., Ltd., JIS Z2502 compliant).

According to the study by the present inventors, it is clear that the conventional sulfide-based inorganic solid electrolyte material has insufficient powder binding properties, and the resulting solid electrolyte membrane may be cracked. Became.
Therefore, the present inventors diligently studied design guidelines for realizing a sulfide-based inorganic solid electrolyte material excellent in lithium ion conductivity and film forming property. As a result, it has been found that a sulfide-based inorganic solid electrolyte material having an angle of repose within a specific range is excellent in binding property between powders, and a solid electrolyte membrane in which cracks are suppressed can be stably obtained.

  The angle of repose of the sulfide-based inorganic solid electrolyte material according to the present embodiment is high in the composition ratio of the sulfide-based inorganic solid electrolyte material and the production conditions such as vitrification after crystallizing the inorganic composition as a raw material. It is possible to realize this by controlling.

In the sulfide-based inorganic solid electrolyte material according to the present embodiment, the maximum diffraction intensity at the position of diffraction angle 2θ = 15.7 ± 0.3 ° in the spectrum obtained by X-ray diffraction using CuKα ray as a radiation source is backed up. a ground intensity _{I a,} when a diffraction intensity of a diffraction peak at the position of the diffraction angle 2θ = 26.9 ± 0.9 ° was _{I B,} preferably the value of I B / _{I a} is 20.0 or less, More preferably, it is 15.0 or less, More preferably, it is 12.0 or less.
The I B _/ I _A With more than the above upper limit, it is possible to further improve the lithium ion conductive sulfide-based inorganic solid electrolyte material. Furthermore, when such a sulfide-based inorganic solid electrolyte material is used, an all-solid-state lithium ion battery having more excellent input / output characteristics can be obtained.

Here, the maximum diffraction intensity at the position of the diffraction angle 2θ = 15.7 ± 0.3 ° is the reference diffraction intensity, and the diffraction peak existing at the position of the diffraction angle 2θ = 26.9 ± 0.9 ° is It is a diffraction peak derived from lithium sulfide.
Therefore, I B _/ I _A represents an indication of the content of lithium sulfide in the sulfide-based inorganic solid electrolyte material during. It means that the smaller I _B / I _A is, the smaller the amount of lithium sulfide contained in the sulfide-based inorganic solid electrolyte material.
Since lithium sulfide has low lithium ion conductivity, it is considered that the lithium ion conductivity of the sulfide-based inorganic solid electrolyte material improves as the lithium sulfide content decreases.
Although the lower limit is not particularly limited because preferably as the I B _/ I _A small as possible, for example, 0.01 or more.

In the sulfide-based inorganic solid electrolyte material according to the present embodiment, lithium ions of the sulfide-based inorganic solid electrolyte material by the AC impedance method under measurement conditions of 27.0 ° C., applied voltage of 10 mV, and measurement frequency range of 0.1 Hz to 7 MHz. The conductivity is preferably 1.0 × 10 ⁻⁴ S · cm ⁻¹ or more, more preferably 2.2 × 10 ⁻⁴ S · cm ⁻¹ or more, and further preferably 2.5 × 10 ⁻⁴ S · cm 1. ⁻¹ or more, 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 the present embodiment is not less than the above lower limit value, an all solid lithium ion battery having further excellent battery characteristics can be obtained.

In the sulfide-based inorganic solid electrolyte material according to this embodiment, the molar ratio (Li / P) of the Li content to the P content in the sulfide-based inorganic solid electrolyte material is preferably 1.0 or more and 10. 0 or less, more preferably 1.5 or more and 5.0 or less, further 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 Is 2.3 or more and 4.3 or less.
The molar ratio (S / P) of the S content to the P content is preferably 1.0 or more and 10.0 or less, more preferably 2.5 or more and 6.0 or less, and still more preferably It is 3.0 or more and 5.0 or less, More preferably, it is 3.5 or more and 4.8 or less, Especially preferably, it is 3.7 or more and 4.5 or less.
Here, the contents of Li, P, and S in the solid electrolyte material of the present embodiment can be determined by, for example, ICP emission spectroscopic analysis.

Examples of the shape of the sulfide-based inorganic solid electrolyte material according to the present embodiment include a particulate shape.
The sulfide-based inorganic solid electrolyte material according to this embodiment is not particularly limited, but the average particle size d ₅₀ in the weight-based particle size distribution by the laser diffraction / scattering particle size distribution measurement method is preferably 1 μm or more and 40 μm or less, more preferably Is 2 μm or more and 30 μm or less, more preferably 3 μm or more and 25 μm or less.
The average particle size d ₅₀ of the sulfide-based inorganic solid electrolyte material to be in the above range, while maintaining good handling properties, it is possible to further improve the lithium ion conductivity of the resulting solid electrolyte membrane.

The sulfide-based inorganic solid electrolyte material according to the present embodiment is used, for example, for a solid electrolyte layer constituting an all solid-state lithium ion battery.
As an example of the all-solid-state lithium ion battery to which the sulfide-based inorganic solid electrolyte material according to the present embodiment is applied, one in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are stacked in this order can be given. In this case, the solid electrolyte layer is composed of a sulfide-based inorganic solid electrolyte material.

[Method for producing sulfide-based inorganic solid electrolyte material]
Next, the manufacturing method of the sulfide type inorganic solid electrolyte material which concerns on this embodiment is demonstrated.
The method for producing a sulfide-based inorganic solid electrolyte material according to this embodiment is different from the conventional method for producing a sulfide-based inorganic solid electrolyte material. The sulfide-based inorganic solid electrolyte material according to the present embodiment having an angle of repose within the above range is a composition ratio of the sulfide-based inorganic solid electrolyte material, crystallization of the inorganic composition as a raw material, and vitrification, etc. It is important to highly control the manufacturing conditions.
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) to (C). Moreover, the manufacturing method of the sulfide type inorganic solid electrolyte material which concerns on this embodiment may further include the following processes (D) and (E).

Step (A): Step of preparing an inorganic composition containing two or more inorganic compounds as raw materials Step (B): Step of crystallizing the inorganic composition by heating the prepared inorganic composition Step (C) : A step of vitrifying the inorganic composition by mechanically reacting the inorganic compounds as raw materials by mechanically treating the crystallized inorganic composition Step (D): the obtained glassy sulfide-based inorganic solid Step of mixing electrolyte material (X) and glass-ceramic sulfide-based inorganic solid electrolyte material (Y) Step (E): Grinding, classifying, or granulating the obtained sulfide-based inorganic solid electrolyte material Process

According to the method for producing a sulfide-based inorganic solid electrolyte material according to the present embodiment, the step of vitrifying the inorganic composition can be greatly shortened as compared with the conventional production method. It is possible to shorten the manufacturing time of the inorganic solid electrolyte material. The reason for this is not clear, but the following reason is presumed.
First, a glassy inorganic composition is in a metastable state. On the other hand, the inorganic composition in the crystalline state is in a stable state. In addition, when an inorganic composition containing two or more inorganic compounds is heated, energy higher than the activation energy can be easily given, so that the crystalline inorganic composition which is in a low energy state can be quickly released along with the release of energy. can get. And since the free energy of a stable state and the free energy of a metastable state are near, it can change from the crystal state of a stable state to the glass state of a metastable state with smaller energy.
For the above reasons, before the step (C) for vitrifying the inorganic composition, the step (B) for crystallizing the inorganic composition is performed, and the inorganic composition is made into a stable crystalline state in advance. It can be considered that a metastable glass state can be obtained with smaller energy, and the step of vitrifying the inorganic composition can be greatly shortened as compared with the conventional production method.
And since it can be set to a metastable glass state with smaller energy, it is considered that the sulfide-based inorganic solid electrolyte material according to the present embodiment having an angle of repose within the above range can be obtained.

  Hereinafter, each step will be described in detail.

(Step of preparing an inorganic composition (A))
First, an inorganic composition containing two or more inorganic compounds as raw materials is prepared.
As the inorganic compound, two or more compounds that chemically react with each other by mechanical treatment to produce a sulfide-based inorganic solid electrolyte material containing Li, P, and S as constituent elements are used. These inorganic compounds can be appropriately selected according to the sulfide-based inorganic solid electrolyte material to be generated. For example, lithium sulfide, phosphorus sulfide, lithium nitride, or the like can be used.

The inorganic composition can be obtained, for example, by mixing two or more inorganic compounds as raw materials at a predetermined molar ratio so that the sulfide-based inorganic solid electrolyte material to be generated has a desired composition ratio. .
The method for mixing two or more inorganic compounds is not particularly limited as long as each inorganic compound can be mixed uniformly. For example, a mortar, ball mill, bead mill, vibration mill, impact grinding apparatus, mixer (pug mixer, Ribbon mixers, tumbler mixers, drum mixers, V-type mixers, etc.), air pulverizers and the like can be used for mixing.
Mixing conditions such as agitation speed, processing time, temperature, reaction pressure, and gravitational acceleration applied to the mixture when mixing each inorganic compound can be appropriately determined depending on the amount of the mixture treated.

It does not specifically limit as lithium sulfide used as a raw material, Commercially available lithium sulfide may be used, for example, lithium sulfide obtained by reaction of lithium hydroxide and hydrogen sulfide may be used. From the viewpoint of obtaining a high-purity sulfide-based inorganic solid electrolyte material and suppressing side reactions, it is preferable to use lithium sulfide with less impurities.
Here, in this embodiment, lithium polysulfide is also included in lithium sulfide.

Is not particularly limited as phosphosulfurized used as a raw material, it is possible to use phosphorus sulfide which is commercially available _{(e.g., P 2 S 5, P 4} S 3, P 4 S 7, P 4 S 5 , etc.). From the viewpoint of obtaining a high-purity sulfide-based inorganic solid electrolyte material and suppressing side reactions, it is preferable to use phosphorus sulfide with less impurities. Further, instead of phosphorus sulfide, simple phosphorus (P) and simple sulfur (S) in a corresponding molar ratio can be used. Simple phosphorus (P) and simple sulfur (S) can be used without particular limitation as long as they are industrially produced and sold.

Lithium nitride may be used as the raw material inorganic compound. Here, since nitrogen in lithium nitride is discharged into the system as N ₂ , a sulfide-based inorganic solid containing Li, P, and S as constituent elements by using lithium nitride as an inorganic compound as a raw material Only the Li composition can be increased with respect to the electrolyte material.
Is not particularly restricted but includes lithium nitride of the present embodiment, the lithium nitride are commercially available (for example, Li 3 _N, etc.) may be used, for example, metallic lithium (eg, Li foil) with nitrogen gas Lithium nitride obtained by the reaction may be used. From the viewpoint of obtaining a high-purity solid electrolyte material and suppressing side reactions, it is preferable to use lithium nitride with less impurities.

(Step of crystallizing inorganic composition (B))
Subsequently, the prepared inorganic composition is heated to crystallize the inorganic composition.
Although it does not specifically limit as temperature at the time of heating an inorganic composition, It is preferable to exist in the range of 200 to 400 degreeC, and it is more preferable to exist in the range of 220 to 320 degreeC.

  The time for heating the inorganic composition is not particularly limited as long as the inorganic composition can be crystallized. For example, it is in the range of 1 minute to 24 hours, preferably 0.1 hour or more. 10 hours or less. The heating method is not particularly limited, and examples thereof include a method using a firing furnace. In addition, conditions, such as temperature and time at the time of such a heating, can be suitably adjusted in order to optimize the characteristic of the inorganic material of this embodiment.

  Whether or not the inorganic composition has been crystallized can be determined by whether or not a new crystal peak has been generated in a spectrum obtained by X-ray diffraction using CuKα rays as a radiation source, for example.

(Step of vitrifying the inorganic composition (C))
Subsequently, the crystallized inorganic composition is mechanically processed to vitrify the inorganic composition while causing a chemical reaction between the inorganic compounds as raw materials.
Here, the mechanical treatment is a method in which two or more inorganic compounds as raw materials are mechanically collided to vitrify the inorganic composition while causing a chemical reaction. For example, mechanochemical treatment, etc. Is mentioned.

  Here, the mechanochemical treatment is a method of vitrification while applying mechanical energy such as shearing force, collision force or centrifugal force to the object to be mixed. Typical examples of vitrification equipment by mechanochemical treatment include ball mills, bead mills, vibration mills, turbo mills, mechano-fusions, disk mills, roll mills and other grinding / dispersing machines, rock drills, vibratory drills, impact drivers, etc. An impact crushing device having a mechanism that combines rotation, extrusion, and impact is exemplified. Among these, a ball mill and a bead mill are preferable, and a ball mill is particularly preferable from the viewpoint that very high impact energy can be efficiently generated. Further, from the viewpoint of excellent continuous productivity, a hitting and grinding device having a mechanism that combines rotation, extrusion, and hitting represented by a rock drill, an impact driver and the like is preferable.

The mechanochemical treatment is preferably performed in an inert atmosphere. Thereby, reaction with an inorganic composition, water vapor | steam, oxygen, etc. can be suppressed.
The term “inactive atmosphere” means a vacuum atmosphere or an inert gas atmosphere. In the non-active atmosphere, the dew point is preferably −50 ° C. or lower, and more preferably −60 ° C. or lower in order to avoid contact with moisture. The “inert gas atmosphere” means an atmosphere of an inert gas such as argon gas, helium gas, nitrogen gas or the like. These inert gases are preferably as high as possible in order to prevent impurities from entering the product. The method of 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. However, the inert gas is purged, and a constant amount of inert gas is continuously introduced. Methods and the like.

  Further, when the crystallized inorganic composition is vitrified, an aprotic organic solvent such as hexane, toluene, or xylene may be added, and the raw material may be dispersed in the solvent.

Mixing conditions such as rotational speed, processing time, temperature, reaction pressure, and gravitational acceleration applied to the inorganic composition when vitrifying the crystallized inorganic composition should be determined appropriately depending on the type of inorganic composition and the amount of treatment. Can do. In general, the faster the rotation speed, the faster the glass production rate, and the longer the treatment time, the higher the conversion to glass.
Usually, when X-ray diffraction analysis using CuKα ray as a radiation source is performed, if the diffraction peak of the crystallized inorganic composition disappears or decreases, the inorganic composition is vitrified, and the desired sulfide-based inorganic It can be determined that a solid electrolyte material is obtained.

Here, in the step (C) of vitrifying the inorganic composition, the maximum diffraction intensity at the diffraction angle 2θ = 15.7 ± 0.3 ° in the spectrum obtained by X-ray diffraction using CuKα rays as the radiation source. was the background intensity _{I a,} when a diffraction intensity of a diffraction peak at the position of the diffraction angle 2θ = 26.9 ± 0.9 ° was _{I B, I B} / _I value of _a is preferably 20.0 In the following, it is preferable to perform the mechanical treatment until it becomes 15.0 or less, more preferably 12.0 or less.
The I B _/ I _A With more than the above upper limit, it is possible to further improve the lithium ion conductive sulfide-based inorganic solid electrolyte material. Furthermore, when such a sulfide-based inorganic solid electrolyte material is used, an all-solid-state lithium ion battery having more excellent input / output characteristics can be obtained.
Here, the maximum diffraction intensity at the position of the diffraction angle 2θ = 15.7 ± 0.3 ° is the reference diffraction intensity, and the diffraction peak existing at the position of the diffraction angle 2θ = 26.9 ± 0.9 ° is It is a diffraction peak derived from lithium sulfide.
Therefore, I B _/ I _A represents an indication of the content of lithium sulfide in the sulfide-based inorganic solid electrolyte material during. It means that the smaller I _B / I _A is, the smaller the amount of lithium sulfide contained in the sulfide-based inorganic solid electrolyte material.
Since lithium sulfide has low lithium ion conductivity, it is considered that the lithium ion conductivity of the sulfide-based inorganic solid electrolyte material improves as the lithium sulfide content decreases.

In the step (C) of vitrifying the inorganic composition, the lithium ion conductivity by the alternating current impedance method under the measurement conditions of 27.0 ° C., applied voltage of 10 mV, and measurement frequency range of 0.1 Hz to 7 MHz is preferably 1. It is preferable to perform mechanical treatment until it becomes 0 × 10 ⁻⁴ S · cm ⁻¹ or more, more preferably 1.2 × 10 ⁻⁴ S · cm ⁻¹ or more. As a result, a sulfide-based inorganic solid electrolyte material that is more excellent in lithium ion conductivity can be obtained.

(Step (D) of mixing glassy sulfide-based inorganic solid electrolyte material and glass-ceramic sulfide-based inorganic solid electrolyte material)
Next, a step of further mixing the glass-ceramic sulfide-based inorganic solid electrolyte material (Y) with the glass-like sulfide-based inorganic solid electrolyte material (X) may be further performed. As a result, a sulfide-based inorganic solid electrolyte material that is more excellent in lithium ion conductivity can be obtained.

  Here, the mixing method of the glassy sulfide-based inorganic solid electrolyte material (X) and the glass-ceramic sulfide-based inorganic solid electrolyte material (Y) is not particularly limited, and examples thereof include a ball mill, a bead mill, and a vibration mill. , Crushing / dispersing machines such as turbo mills, mechano-fusions, disk mills, roll mills, etc., and crushing and crushing devices composed of a combination of rotation, extrusion and hammering, represented by rock drills, vibration drills, impact drivers, etc. A mixing method is mentioned.

Further, it is preferable that the glassy sulfide-based inorganic solid electrolyte material (X) and the glass-ceramic sulfide-based inorganic solid electrolyte material (Y) are mixed in an inert atmosphere. Thereby, reaction with sulfide system inorganic solid electrolyte material, water vapor, oxygen, etc. can be controlled.
The term “inactive atmosphere” means a vacuum atmosphere or an inert gas atmosphere. In the non-active atmosphere, the dew point is preferably −50 ° C. or lower, and more preferably −60 ° C. or lower in order to avoid contact with moisture. The “inert gas atmosphere” means an atmosphere of an inert gas such as argon gas, helium gas, nitrogen gas or the like. These inert gases are preferably as high as possible in order to prevent impurities from entering the product. The method of 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. However, the inert gas is purged, and a constant amount of inert gas is continuously introduced. Methods and the like.

Rotational speed, processing time, temperature, reaction pressure, and gravity applied to the mixture when mixing glassy sulfide-based inorganic solid electrolyte material (X) and glass-ceramic sulfide-based inorganic solid electrolyte material (Y) Mixing conditions such as acceleration can be appropriately determined depending on the type of mixture and the amount of processing.
Usually, when X-ray diffraction analysis using CuKα ray as a radiation source is performed, if the diffraction peak of the glass-ceramic sulfide-based inorganic solid electrolyte material (Y) disappears or decreases, the glass-based sulfide-based It can be determined that the inorganic solid electrolyte material (X) and the glass-ceramic sulfide-based inorganic solid electrolyte material (Y) are sufficiently mixed to obtain a desired sulfide-based inorganic solid electrolyte material.

  The glass-ceramic sulfide-based inorganic solid electrolyte material (Y) can be obtained, for example, by heating the glass-like sulfide-based inorganic solid electrolyte material (X). Although it does not specifically limit as temperature at the time of heating glass-like sulfide type inorganic solid electrolyte material (X), It is preferable to exist in the range of 200 degreeC or more and 400 degrees C or less, and in the range of 220 degrees C or more and 320 degrees C or less It is more preferable that

  The time for heating the glassy sulfide-based inorganic solid electrolyte material (X) is not particularly limited as long as the glassy sulfide-based inorganic solid electrolyte material (X) can be converted into a glass ceramic, For example, it is in the range of 1 minute to 24 hours, preferably 0.1 hours to 10 hours. The heating method is not particularly limited, and examples thereof include a method using a firing furnace. In addition, conditions, such as temperature and time at the time of such a heating, can be suitably adjusted in order to optimize the characteristic of the inorganic material of this embodiment.

  In addition, whether the glassy sulfide-based inorganic solid electrolyte material (X) has become a glass ceramic, for example, a new crystal peak is generated in a spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. It can be judged by whether or not.

The mixing ratio (mass ratio) of the glass-ceramic sulfide-based inorganic solid electrolyte material (Y) to the glass-like sulfide-based inorganic solid electrolyte material (X) is not particularly limited, but is preferably 0.1 or more and 10 or less, More preferably, it is 0.2 or more and 5.0 or less, More preferably, it is 0.4 or more and 2.0 or less, Especially preferably, it is 0.6 or more and 1.5 or less.
When the mixing ratio is within the above range, the balance between lithium ion conductivity and film forming property of the obtained sulfide-based inorganic solid electrolyte material is further improved.

(Step of grinding, classifying or granulating (E))
In the method for producing a sulfide-based inorganic solid electrolyte material according to this embodiment, a step of pulverizing, classifying, or granulating the obtained sulfide-based inorganic solid electrolyte material may be further performed as necessary. For example, a sulfide-based inorganic solid electrolyte material having a desired particle diameter can be obtained by making fine particles by pulverization and then adjusting the particle diameter by classification operation or granulation operation. It does not specifically limit as said grinding | pulverization method, Well-known grinding | pulverization methods, such as a mixer, airflow grinding | pulverization, a mortar, a rotary mill, a coffee mill, can be used. Moreover, it does not specifically limit as said classification method, Well-known methods, such as a sieve, can be used.
These pulverization or classification are preferably performed in an inert gas atmosphere or a vacuum atmosphere from the viewpoint that contact with moisture in the air can be prevented.

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

The solid electrolyte membrane according to the present embodiment is used for, for example, a solid electrolyte layer constituting an all solid-state lithium ion battery.
As an example of the all solid-state lithium ion battery to which the solid electrolyte membrane according to the present embodiment is applied, a battery in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are stacked in this order can be given. In this case, the solid electrolyte layer is constituted by 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 further preferably 20 μm or more and 100 μm or less. When the average thickness of the solid electrolyte membrane is equal to or more than the lower limit, it is possible to further suppress the loss of the sulfide-based inorganic solid electrolyte material and the occurrence of cracks on the surface of the solid electrolyte membrane. Moreover, the impedance of a solid electrolyte membrane can be further reduced as the average thickness of the said solid electrolyte membrane is below the said upper limit. As a result, the battery characteristics of the obtained all solid-state lithium ion battery can be further improved.

The solid electrolyte membrane according to the present embodiment is preferably a pressure formed body of a powdered sulfide-based inorganic solid electrolyte material. That is, it is preferable to pressurize the particulate inorganic solid electrolyte material to obtain a solid electrolyte membrane having a certain strength due to the anchor effect between the inorganic solid electrolyte materials.
By using a pressure-molded body, the inorganic solid electrolyte materials are bonded to each other, and the strength of the obtained solid electrolyte membrane is further increased. As a result, the loss of the inorganic solid electrolyte material and the occurrence of cracks on the surface of the inorganic solid electrolyte material can be further suppressed.

  The content of the sulfide-based inorganic solid electrolyte material according to the present embodiment in the solid electrolyte membrane according to the present embodiment is preferably 98% by mass or more when the entire solid electrolyte membrane is 100% by mass. Preferably it is 99 mass% or more, More preferably, it is 100 mass%. Thereby, the contact property between inorganic solid electrolyte materials is improved, and the interface contact resistance of a solid electrolyte membrane can be reduced. As a result, the lithium ion conductivity of the solid electrolyte membrane can be further improved. And the battery characteristic of the all-solid-state type lithium ion battery obtained can be further improved by using such a solid electrolyte membrane excellent in lithium ion conductivity.

  The planar shape of the solid electrolyte membrane is not particularly limited and can be appropriately selected according to the shape of the electrode layer or the current collector layer. For example, it can be rectangular.

Further, 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% by mass when the entire solid electrolyte membrane is 100% by mass. More preferably, it is 0.1 mass% or less, More preferably, it is 0.05 mass% or less, More preferably, it is 0.01 mass% or less. Further, the solid electrolyte membrane according to this embodiment is still more preferably substantially free of binder resin, and most preferably free of binder resin.
Thereby, the contact property between solid electrolyte materials is improved, and the interface contact resistance of a solid electrolyte membrane can be reduced. As a result, the lithium ion conductivity of the solid electrolyte membrane can be further improved. And the battery characteristic of the obtained all-solid-type lithium ion battery can be improved by using the solid electrolyte membrane excellent in such lithium ion conductivity.
Note that “substantially free of binder resin” means that it may be contained to the extent that the effects of the present embodiment are not impaired. Further, 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 derived from the adhesive resin layer present in the vicinity of the interface between the solid electrolyte layer and the adhesive resin layer is “ It is removed from the “binder resin in the solid electrolyte membrane”.

  The binder resin refers to a binder generally used for lithium ion batteries in order to bind solid electrolyte materials. For example, polyvinyl alcohol, polyacrylic acid, carboxymethyl cellulose, polytetrafluoroethylene. , Polyvinylidene fluoride, styrene / butadiene rubber, polyimide and the like.

The solid electrolyte membrane according to the present embodiment is obtained by depositing, for example, a powdered sulfide-based inorganic solid electrolyte material in a film shape on the cavity surface or the substrate surface of a mold, and then the sulfide deposited in the film shape. It can be obtained by pressurizing the inorganic inorganic electrolyte material.
The method for pressurizing the sulfide-based inorganic solid electrolyte material is not particularly limited. For example, when powdered sulfide-based inorganic solid electrolyte material is deposited on the cavity surface of the mold, pressing with a mold and a pressing mold is performed. When the powdered sulfide-based inorganic solid electrolyte material is deposited on the surface of the substrate, a press using a die and a pressing die, a roll press, a flat plate press, or the like can be used.
The pressure for pressurizing the sulfide-based inorganic solid electrolyte material is, for example, 10 MPa or more and 500 MPa or less.

If necessary, the sulfide-based inorganic solid electrolyte material deposited in a film shape may be pressurized and heated. If heating and pressurization is performed, the sulfide-based inorganic solid electrolyte materials are fused and bonded to each other, and the strength of the obtained solid electrolyte membrane is further increased. As a result, the loss 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 which heats a sulfide type inorganic solid electrolyte material is 40 degreeC or more and 500 degrees C or less, for example.

[All-solid-state lithium-ion battery]
Next, the all solid-state lithium ion battery 200 according to the present embodiment will be described. FIG. 1 is a cross-sectional view schematically showing an example of the structure of an all solid-state lithium ion battery 200 according to an embodiment of the present invention. The all solid-state lithium ion battery 200 according to the present embodiment is a lithium ion secondary battery, but may be a lithium ion primary battery.

The all solid-state lithium ion battery 200 according to the present embodiment includes a positive electrode layer 210, a solid electrolyte layer 220, and a negative electrode layer 230 that are stacked in this order. And the solid electrolyte layer 220 is comprised by the solid electrolyte membrane which concerns on this embodiment.
In addition, the all-solid-state lithium ion battery 200 according to the embodiment includes a bipolar lithium-ion battery by stacking two or more unit cells each including a positive electrode layer 210, a solid electrolyte layer 220, and a negative electrode layer 230. It can also be.
The shape of the all-solid-state lithium ion battery 200 is not particularly limited, and examples thereof include a cylindrical shape, a coin shape, a square shape, a film shape, and other arbitrary shapes.

  The all-solid-state lithium ion battery 200 according to the present embodiment is generally manufactured according to a known method. For example, the positive electrode layer 210, the solid electrolyte layer 220, and the negative electrode layer 230 are stacked to form a cylindrical shape, a coin shape, a square shape, a film shape, or any other shape.

The positive electrode layer 210 is not particularly limited, and a positive electrode generally used for an all solid-state lithium ion battery can be used. The positive electrode layer 210 is not particularly limited, but can be generally manufactured according to a known method. For example, it can be obtained by forming a positive electrode active material layer containing a positive electrode active material on a current collector such as an aluminum foil.
The thickness and density of the positive electrode active material layer are not particularly limited because they are appropriately determined according to the intended use of the battery, and can be set according to generally known information.

The positive electrode active material layer includes a positive electrode active material.
It does not specifically limit as a positive electrode active material, The generally well-known positive electrode active material which can be used for the positive electrode layer of an all-solid-state type lithium ion battery can be used. For example, lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), solid solution oxide (Li ₂ MnO ₃ —LiMO ₂ (M = Co, Ni, etc.) ), Lithium-manganese-nickel oxide (LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ), olivine-type lithium phosphorus oxide (LiFePO ₄ ) and other complex oxides; polyaniline, polypyrrole and other highly conductive materials Molecule: sulfide positive electrode active such as Li ₂ S, CuS, Li—Cu—S compound, TiS ₂ , FeS, MoS ₂ , Li—Mo—S compound, Li—Ti—S compound, Li—VS compound Substances: Acetylene black impregnated with sulfur, porous carbon impregnated with sulfur, sulfur-carbon mixed powder, etc. It is possible. These positive electrode active materials may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, from the viewpoint of having a higher discharge capacity density and more excellent cycle characteristics, a sulfide-based positive electrode active material is preferable, and a Li—Mo—S compound, a Li—Ti—S compound, a Li—V—S is preferable. One or more selected from compounds are more preferred.

Here, the Li—Mo—S compound contains Li, Mo, and S as constituent elements, and is usually obtained by mixing and grinding molybdenum sulfide and lithium sulfide, which are raw materials, such as mechanochemical treatment. be able to.
Li-Ti-S compounds contain Li, Ti, and S as constituent elements, and are usually obtained by mixing and grinding titanium sulfide and lithium sulfide, which are raw materials, such as mechanochemical treatment. Can do.
The Li-VS compound contains Li, V, and S as constituent elements, and can usually be obtained by mixing and grinding vanadium sulfide and lithium sulfide, which are raw materials, such as mechanochemical treatment. .

Although the said positive electrode active material layer is not specifically limited, As a component other than a positive electrode active material, 1 type, or 2 or more types of materials selected from a solid electrolyte material, a binder, a conductive support agent, etc. may be included, for example.
The mixing ratio of various materials in the positive electrode active material layer is not particularly limited because it is appropriately determined according to the intended use of the battery, and can be generally set according to known information.

The negative electrode layer 230 is not particularly limited, and those commonly used in all solid-state lithium ion batteries can be used. The negative electrode layer 230 is not particularly limited, but can generally be manufactured according to a known method. For example, it can be obtained by forming a negative electrode active material layer containing a negative electrode active material on a current collector such as a copper foil.
The thickness and density of the negative electrode active material layer are not particularly limited because they are appropriately determined according to the intended use of the battery and the like, and can generally be set according to known information.

The negative electrode active material layer includes a negative electrode active material.
It does not specifically limit as a negative electrode active material, The generally well-known negative electrode active material which can be used for the negative electrode layer of an all-solid-type lithium ion battery can be used. For example, carbonaceous materials such as natural graphite, artificial graphite, resin charcoal, carbon fiber, activated carbon, hard carbon, soft carbon; tin, tin alloy, silicon, silicon alloy, gallium, gallium alloy, indium, indium alloy, aluminum, aluminum Examples thereof include metal materials mainly composed of alloys; conductive polymers such as polyacene, polyacetylene, and polypyrrole; metal lithium; lithium titanium composite oxide (for example, Li ₄ Ti ₅ O ₁₂ ). These negative electrode active materials may be used individually by 1 type, and may be used in combination of 2 or more type.

Although the said negative electrode active material layer is not specifically limited, As a component other than a negative electrode active material, 1 type, or 2 or more types of materials selected from a solid electrolyte material, a binder, a conductive support agent, etc. may be included, for example.
The mixing ratio of various materials in the negative electrode active material layer is not particularly limited because it is appropriately determined according to the intended use of the battery and the like, and can be generally set according to known information.

As mentioned above, although embodiment of this invention was described, these are illustrations of this invention and various structures other than the above are also employable.
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these.

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

(1) Particle size distribution Particle size distribution of sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples by a laser diffraction method using a laser diffraction / scattering particle size distribution measuring device (manufactured by Malvern, Mastersizer 3000). Was measured. From the measurement results, for each sulfide-based inorganic solid electrolyte material, the particle size (D ₅₀ , average particle size) at 50% accumulation in the weight-based cumulative distribution was determined.

(2) ICP emission spectroscopic analysis Using an ICP emission spectroscopic analyzer (Seiko Instruments Inc., SPS3000), measurement was performed by ICP emission spectroscopic analysis, and sulfide-based inorganic solid electrolytes obtained in Examples and Comparative Examples The mass% of each element in the material was determined, and the molar ratio of each element was calculated based on that.

(3) X-ray diffraction analysis Using an X-ray diffractometer (RINT2000, RINT2000), the diffraction spectra of the sulfide-based inorganic solid electrolyte materials obtained in the examples and comparative examples were obtained by X-ray diffraction analysis, respectively. Asked. Note that CuKα rays were used as the radiation source. Here, the maximum diffraction intensity at the position of the diffraction angle 2θ = 15.7 ± 0.3 ° and background intensity _{I A,} the diffraction of the diffraction peak at the position of the diffraction angle 2θ = 26.9 ± 0.9 ° the intensity and _{I B,} was obtained _I B / I _a.

(4) Measurement of lithium ion conductivity Lithium ion conductivity was measured by an alternating current impedance method for the sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples.
For the measurement of lithium ion conductivity, a potentiostat / galvanostat SP-300 manufactured by Hokuto Denko Corporation was used. The sample size was φ9.5 mm, thickness 1.3 mm, measurement conditions were applied voltage 10 mV, measurement temperature 27.0 ° C., measurement frequency range 0.1 Hz to 7 MHz, and the electrode was Li foil.
Here, as a sample for measuring lithium ion conductivity, a thickness obtained by pressing a powdery sulfide-based inorganic solid electrolyte material obtained in Examples and Comparative Examples at 270 MPa for 10 minutes using a press device. A plate-like sulfide-based inorganic solid electrolyte material having a thickness of 1.3 mm was used.

(5) Measurement of repose angle The repose angle was measured by an injection method using a powder rheometer (Furukawa Machine Metal Co., Ltd., JIS Z2502 compliant). 5 g of the powdered sulfide-based inorganic solid electrolyte material obtained in Examples and Comparative Examples was weighed, and the sulfide-based inorganic solid electrolyte material was passed through an orifice of φ2.63 mm (discharge hole diameter) at the bottom of the funnel (inclination angle 60 °). Were deposited in a conical shape on a φ14 mm disk, and the angle (repose angle) α formed by the generatrix and the bottom of the cone was measured. Here, the distance from the discharge hole of the funnel to the disc was 25 mm.
tan α = cone height / (0.5 × diameter of disk)

(6) Evaluation of film forming property 10 mg of the powdered sulfide-based inorganic solid electrolyte material obtained in Examples and Comparative Examples was press-molded at 270 MPa to φ14 mm × 0.4 mm to prepare a solid electrolyte membrane. Subsequently, the surface of the obtained solid electrolyte membrane was observed with an electron microscope (SEM), and the film forming property of the sulfide-based inorganic solid electrolyte material was evaluated according to the following criteria.
○: The binding property between the powders of the sulfide-based inorganic solid electrolyte material is good, and the powders of the sulfide-based inorganic solid electrolyte material are bound together, and the sulfide-based inorganic solid electrolyte material is densified. : Sulfide-based inorganic solid electrolyte material powder has poor binding properties, fine cracks are generated on the surface of the solid electrolyte membrane, and the sulfide-based inorganic solid electrolyte material is not densified

<Example 1>
A powdery sulfide-based inorganic solid electrolyte material containing Li, P, and S as constituent elements was prepared by the following procedure.
Li ₂ S (manufactured by Alfa Aesar, purity 99.9%) and P ₂ S ₅ (reagent manufactured by Kanto Chemical) were used as raw materials. Li ₃ N was produced by the following procedure.
First, in a nitrogen atmosphere glove box, a stainless steel sword mountain was used for Li foil (purity 99.8%, thickness 0.5 mm manufactured by Honjo Metal Co., Ltd.), and a number of holes having a diameter of 1 mm or less were formed. The Li foil began to turn black-purple from the hole, and all the Li foil changed to black-purple Li ₃ N by leaving it at room temperature for 24 hours. Li ₃ N was pulverized in an agate mortar and then sieved with a stainless steel sieve, and a powder of 75 μm or less was recovered and used as a raw material for sulfide-based inorganic solid electrolyte material.
Subsequently, each raw material was precisely weighed in an argon glove box so that Li ₂ S: P ₂ S ₅ : Li ₃ N = 67.5: 22.5: 10.0 (mol%). The mixture was mixed in an agate mortar for 20 minutes to obtain an inorganic composition. Next, 5 g of the inorganic composition was weighed and heat-treated in an alumina crucible at 300 ° C. for 1 hour to crystallize the inorganic composition. Next, 2 g of the crystallized inorganic composition was weighed, put into an alumina ball mill pot (internal volume 400 mL) together with 500 g of zirconia balls having a diameter of 10 mm, and mixed and pulverized at 125 rpm for 6 hours to obtain a sulfide-based inorganic solid electrolyte material. Obtained.
Each evaluation was performed about the obtained sulfide type inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Examples 2 to 4>
A sulfide-based inorganic solid electrolyte material was prepared in the same manner as in Example 1 except that the ratio of each raw material was changed so that Li / P and S / P were values shown in Table 1, and each evaluation was performed. It was. The obtained results are shown in Table 1, respectively.

<Example 5>
Li ₂ S (manufactured by Alfa Aesar, purity 99.9%) and P ₂ S ₅ (reagent manufactured by Kanto Chemical) were used as raw materials. Subsequently, each raw material was precisely weighed so that Li ₂ S: P ₂ S ₅ = 80.0: 20.0 (mol%) in an argon glove box, and these powders were mixed in an agate mortar for 10 minutes. An inorganic composition was obtained. Next, 5 g of the inorganic composition was weighed and heat-treated at 220 ° C. for 1 hour in an alumina crucible to crystallize the inorganic composition. 2 g of the crystallized inorganic composition was weighed, put together with 500 g of φ10 mm zirconia balls into an alumina ball mill pot (internal volume 400 mL), and mixed and pulverized at 125 rpm for 6 hours to obtain a sulfide-based inorganic solid electrolyte material. .
Each evaluation was performed about the obtained sulfide type inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Example 6>
A sulfide-based inorganic solid electrolyte material was prepared and evaluated in the same manner as in Example 5 except that the heat treatment temperature of the inorganic composition was changed to 240 ° C. The obtained results are shown in Table 1.

<Example 7>
A sulfide-based inorganic solid electrolyte material was prepared and evaluated in the same manner as in Example 5 except that the heat treatment temperature of the inorganic composition was changed to 260 ° C. The obtained results are shown in Table 1.

<Example 8>
A sulfide-based inorganic solid electrolyte material was produced in the same manner as in Example 5 except that the heat treatment temperature of the inorganic composition was changed to 280 ° C., and each evaluation was performed. The obtained results are shown in Table 1.

<Example 9>
A sulfide-based inorganic solid electrolyte material was prepared and evaluated in the same manner as in Example 5 except that the heat treatment temperature of the inorganic composition was changed to 300 ° C. The obtained results are shown in Table 1.

<Example 10>
The same as Example 5 except that the heat treatment temperature of the inorganic composition was changed to 280 ° C., and the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ = 70.0: 30.0 (mol%). Thus, a sulfide-based inorganic solid electrolyte material was prepared and evaluated. The obtained results are shown in Table 1.

<Example 11>
The same as in Example 5 except that the heat treatment temperature of the inorganic composition was changed to 280 ° C. and the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ = 75.0: 25.0 (mol%). Thus, each of the sulfide-based inorganic solid electrolyte materials was prepared and evaluated.
The obtained results are shown in Table 1.

<Example 12>
Li ₂ S (manufactured by Alfa Aesar, purity 99.9%) and P ₂ S ₅ (reagent manufactured by Kanto Chemical) were used as raw materials. Subsequently, each raw material was precisely weighed so that Li ₂ S: P ₂ S ₅ = 80.0: 20.0 (mol%) in an argon glove box, and these powders were mixed in an agate mortar for 10 minutes. An inorganic composition was obtained. Next, 5 g of the inorganic composition was weighed and heat-treated at 300 ° C. for 1 hour in an alumina crucible to crystallize the inorganic composition. 2 g of the crystallized inorganic composition was weighed, put together with 500 g of φ10 mm zirconia balls into an alumina ball mill pot (internal volume 400 mL), and mixed and pulverized at 125 rpm for 6 hours to obtain a sulfide-based inorganic solid electrolyte material. . Each evaluation was performed about the obtained sulfide type inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Comparative Example 1>
Li ₂ S (manufactured by Alfa Aesar, purity 99.9%) and P ₂ S ₅ (reagent manufactured by Kanto Chemical) were used as raw materials. Subsequently, each raw material was precisely weighed so that Li ₂ S: P ₂ S ₅ = 80.0: 20.0 (mol%) in an argon glove box, and these powders were mixed in an agate mortar for 20 minutes. An inorganic composition was obtained. Next, 2 g of the inorganic composition was weighed, put together with 500 g of φ10 mm zirconia balls into an alumina ball mill pot (internal volume 400 mL), and mixed and ground at 125 rpm for 200 hours to obtain a sulfide-based inorganic solid electrolyte material. Each evaluation was performed about the obtained sulfide type inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Comparative example 2>
2 g of the glassy sulfide-based inorganic solid electrolyte material obtained in Example 1 is weighed and heated in an argon glove box at 300 ° C. for 2 hours to obtain a glass-ceramic sulfide-based inorganic solid electrolyte material. It was. Each evaluation was performed about the obtained glass-ceramic sulfide type inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Example 13>
The glassy sulfide-based inorganic solid electrolyte material obtained in Example 1 and the glass-ceramic sulfide-based inorganic solid electrolyte material obtained in Comparative Example 2 were weighed so as to have a mass ratio of 5: 5. These powders were mixed in an agate mortar for 20 minutes. Next, 2 g of the mixed powder was weighed and put into an alumina ball mill pot (internal volume 400 mL) together with 500 g of zirconia balls having a diameter of 10 mm, and mixed at 125 rpm for 1 hour to obtain a sulfide-based inorganic solid electrolyte material. Each evaluation was performed about the obtained sulfide type inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Comparative Example 3>
2 g of the glassy sulfide-based inorganic solid electrolyte material obtained in Example 12 was weighed and heat-treated in an argon glove box at 270 ° C. for 2 hours to obtain a glass-ceramic sulfide-based inorganic solid electrolyte material. It was. Each evaluation was performed about the obtained glass-ceramic sulfide type inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Example 14>
The glassy sulfide-based inorganic solid electrolyte material obtained in Example 12 and the glass-ceramic sulfide-based inorganic solid electrolyte material obtained in Comparative Example 3 were weighed so as to have a mass ratio of 5: 5. These powders were mixed in an agate mortar for 20 minutes. Next, 2 g of the mixed powder was weighed and put into an alumina ball mill pot (internal volume 400 mL) together with 500 g of zirconia balls having a diameter of 10 mm, and mixed at 125 rpm for 1 hour to obtain a sulfide-based inorganic solid electrolyte material. Each evaluation was performed about the obtained sulfide type inorganic solid electrolyte material. The obtained results are shown in Table 1.

The sulfide-based inorganic solid electrolyte materials of Examples 1 to 14 having an angle of repose of 57 ° to 70 ° were excellent in lithium ion conductivity and film forming property. On the other hand, the sulfide-based inorganic solid electrolyte materials of Comparative Examples 1 to 3 having an angle of repose of less than 57 ° were inferior in film forming property although they were excellent in lithium ion conductivity.
Further, the sulfide-based inorganic solid electrolyte materials of Examples 13 and 14 obtained by mixing a glass-like sulfide-based inorganic solid electrolyte material and a glass-ceramic sulfide-based inorganic solid electrolyte material are lithium ion conductive. Was particularly good.

200 all-solid-state lithium ion battery 210 positive electrode layer 220 solid electrolyte layer 230 negative electrode layer

Claims (10)

A powdered sulfide-based inorganic solid electrolyte material having lithium ion conductivity and containing Li, P and S as constituent elements,
A sulfide-based inorganic solid electrolyte material having an angle of repose of 57 ° to 70 ° measured at 25 ° C. in an argon atmosphere. The sulfide-based inorganic solid electrolyte material according to claim 1,
The molar ratio (Li / P) of the Li content to the P content in the sulfide-based inorganic solid electrolyte material is 1.0 or more and 10.0 or less, and the S content relative to the P content A sulfide-based inorganic solid electrolyte material having a molar ratio (S / P) of 1.0 to 10.0. The sulfide-based inorganic solid electrolyte material according to claim 1 or 2,
In weight particle size distribution by a laser diffraction scattering particle size distribution measurement method, the sulfide-based inorganic solid electrolyte average particle size d ₅₀ of material is 1μm or more 40μm or less sulfide-based inorganic solid electrolyte material. In the sulfide system inorganic solid electrolyte material according to any one of claims 1 to 3,
A sulfide-based inorganic solid electrolyte material used for a solid electrolyte layer constituting an all solid-state lithium ion battery. In the sulfide system inorganic solid electrolyte material according to any one of claims 1 to 4,
In the spectrum obtained by X-ray diffraction using a CuKα ray the highest diffraction intensity at the position of the diffraction angle 2θ = 15.7 ± 0.3 ° and background intensity _{I A} as a radiation source, a diffraction angle 2 [Theta] = 26.9 ± _A sulfide-based inorganic solid electrolyte material in which the value of I _B / IA is 20.0 or less, where I _B is the diffraction intensity of a diffraction peak present at a position of 0.9 °. The sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 5,
The sulfide-based inorganic solid electrolyte material has a lithium ion conductivity of 1.0 × 10 ⁻⁴ S · cm according to an AC impedance method under 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 sulfide-based inorganic solid electrolyte material that is ⁻¹ or more.   The solid electrolyte membrane which contains the sulfide type inorganic solid electrolyte material as described in any one of Claims 1 thru | or 6 as a main component. An all-solid-state lithium ion battery in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are laminated in this order,
An all-solid-state lithium ion battery in which the solid electrolyte layer is constituted by the solid electrolyte membrane according to claim 7. A manufacturing method for manufacturing the sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 6,
A method for producing a sulfide-based inorganic solid electrolyte material comprising a step of mixing a glassy sulfide-based inorganic solid electrolyte material (X) and a glass-ceramic sulfide-based inorganic solid electrolyte material (Y). A method for producing a sulfide-based inorganic solid electrolyte material according to claim 9,
A sulfide-based inorganic material having a mixing ratio (mass ratio) of the glass-ceramic sulfide-based inorganic solid electrolyte material (Y) to the glassy sulfide-based inorganic solid electrolyte material (X) of 0.1 to 10 A method for producing a solid electrolyte material.

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