JP7427821B2 - Sulfide-based inorganic solid electrolyte materials, solid electrolytes, solid electrolyte membranes, and lithium ion batteries - Google Patents

Description

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

Lithium ion batteries are commonly used as power sources for small portable devices such as mobile phones and notebook computers. Furthermore, in addition to small portable devices, lithium ion batteries have recently begun to be used as power sources for electric vehicles, power storage, and the like.

Lithium ion batteries currently on the market use electrolytes containing flammable organic solvents. On the other hand, lithium-ion batteries (hereinafter also referred to as all-solid-state lithium-ion batteries), which are made completely solid by changing the electrolyte to a solid electrolyte, do not use flammable organic solvents in the battery, so they have safety features. It is considered to be superior in manufacturing cost and productivity.

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 (Japanese Unexamined Patent Publication No. 2016-27545) has a peak at the 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 is described having a composition of .1≦y≦0.175).

JP2016-27545A

According to studies conducted by the present inventors, it has become clear that when a sulfide-based inorganic solid electrolyte material is exposed to the atmosphere, the lithium ion conductivity may gradually decrease.
That is, conventional sulfide-based inorganic solid electrolyte materials have room for improvement in terms of suppressing a decrease in lithium ion conductivity when exposed to the atmosphere.

The present invention has been made in view of the above circumstances, and provides a sulfide-based inorganic solid electrolyte material that can suppress a decrease in lithium ion conductivity when exposed to the atmosphere.

The present inventors have conducted extensive studies in order to provide a sulfide-based inorganic solid electrolyte material that can suppress a decrease in lithium ion conductivity when exposed to the atmosphere. As a result, they discovered that a sulfide-based inorganic solid electrolyte material that generates a small amount of hydrogen sulfide measured by a specific method can suppress the decline in lithium ion conductivity when exposed to the atmosphere, leading to the present invention. .

That is, according to the present invention,
A 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 is provided that generates hydrogen sulfide in an amount of 20 ppm or less, as measured by the method described below.
(Method)
The sulfide-based inorganic solid electrolyte material is placed in a glass sealed container that has been purged with argon gas, and then water is dripped onto the sulfide-based inorganic solid electrolyte material from the top of the glass sealed container for 5 minutes. Afterwards, the amount of hydrogen sulfide gas generated in the glass sealed container is measured.

Further, according to the present invention,
A solid electrolyte containing the above sulfide-based inorganic solid electrolyte material is provided.

Furthermore, according to the present invention,
A solid electrolyte membrane containing the above solid electrolyte as a main component is provided.

Furthermore, according to the present invention,
A lithium ion battery comprising a positive electrode including a positive electrode active material layer, an electrolyte layer, and a negative electrode including a negative electrode active material layer,
A lithium ion battery is provided in which at least one of the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer includes the sulfide-based inorganic solid electrolyte material.

According to the present invention, it is possible to provide a sulfide-based inorganic solid electrolyte material that can suppress a decrease in lithium ion conductivity when exposed to the atmosphere.

1 is a cross-sectional view showing an example of the structure of a lithium ion battery according to an embodiment of the present invention. FIG. 2 is a diagram showing an X-ray diffraction spectrum of a sulfide-based inorganic solid electrolyte material obtained in an example. FIG. 3 is a diagram showing an X-ray diffraction spectrum of a sulfide-based inorganic solid electrolyte material obtained in a comparative example. FIG. 2 is a diagram showing a photograph of an apparatus used to measure the amount of hydrogen sulfide generated from sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples.

Embodiments of the present invention will be described below with reference to the drawings. Note that, in all the drawings, similar constituent elements are given the same reference numerals, and description thereof will be omitted as appropriate. Furthermore, the figure is a schematic diagram and does not correspond to the actual dimensional ratio. Unless otherwise specified, the numerical range "A to B" represents a value greater than or equal to A and less than or equal to B.

[Sulfide-based inorganic solid electrolyte material]
First, the sulfide-based inorganic solid electrolyte material according to this embodiment will be explained.
The sulfide-based inorganic solid electrolyte material according to the present embodiment is a sulfide-based inorganic solid electrolyte material that has lithium ion conductivity and contains Li, P, and S as constituent elements, and is measured by the following method. The amount of hydrogen sulfide generated is 20 ppm or less, preferably 15 ppm or less, more preferably 10 ppm or less. The lower limit of the amount of hydrogen sulfide generated is not particularly limited, but is, for example, 1 ppm or more, preferably 0.1 ppm or more.
(Method)
The sulfide-based inorganic solid electrolyte material is placed in a glass sealed container that has been purged with argon gas, and then water is dripped onto the sulfide-based inorganic solid electrolyte material from the top of the glass sealed container for 5 minutes. Afterwards, the amount of hydrogen sulfide gas generated in the glass sealed container is measured.

The sulfide-based inorganic solid electrolyte material according to the present embodiment exhibits a decrease in lithium ion conductivity when exposed to the atmosphere because the amount of hydrogen sulfide generated is equal to or less than the upper limit value as measured by the method described above. can be suppressed. Furthermore, when the amount of hydrogen sulfide generated is below the above upper limit, lithium ion conductivity can be improved.
Although the reason for this is not necessarily clear, the following reasons are inferred.
This is considered to be because a sulfide-based inorganic solid electrolyte material that generates hydrogen sulfide in an amount below the above upper limit has a structure that is difficult to react with moisture contained in the atmosphere.
Therefore, the fact that the amount of hydrogen sulfide generated, measured by the above method, is below the above upper limit value indicates that a new structure different from that of conventional typical sulfide-based inorganic solid electrolyte materials has been formed. It is thought that it represents.
In this embodiment, the sulfide-based inorganic solid electrolyte material whose hydrogen sulfide generation amount is below the upper limit value is obtained by highly controlling the composition ratio of the sulfide-based inorganic solid electrolyte material and by combining shear stress and compressive stress. The process of vitrifying and annealing the inorganic composition as a raw material is performed continuously using a grinding device, and the sulfide-based inorganic solid electrolyte material is processed by applying stronger shear and compression forces than conventional ones. This can be achieved by manufacturing or the like.

The sulfide-based inorganic solid electrolyte material according to the present embodiment has a position at a diffraction angle 2θ=17.2±0.5° and a diffraction angle 2θ=25° in a spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. It is preferable to have a diffraction peak at a position of .6±0.5° and a diffraction angle of 2θ=29.2±0.8°.
Thereby, lithium ion conductivity can be improved while maintaining good electrochemical stability.

The sulfide-based inorganic solid electrolyte material according to the present embodiment backs the maximum diffraction intensity at the position of diffraction angle 2θ = 35.0 ± 0.1° in the spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. When the ground intensity _IA is the maximum diffraction intensity of the diffraction peak existing at the diffraction angle 2θ=17.2±0.5° _IB , the value of _IB / _IA is preferably 2.0 or more. , more preferably 3.5 or more, still more preferably 5.0 or more, particularly preferably 6.0 or more.
By setting the value of I _B /I _A to be equal to or greater than the above lower limit, lithium ion conductivity can be further improved.
Further, in the sulfide-based inorganic solid electrolyte material according to the present embodiment, the upper limit of the value of I _B /I _A is not particularly limited, but is, for example, 30.0 or less, preferably 20.0 or less, and more preferably 15.0 or less. It is 0 or less, particularly preferably 13.0 or less.
The value of I _B /I _A of the sulfide-based inorganic solid electrolyte material according to the present embodiment can be determined by adjusting the composition ratio of the sulfide-based inorganic solid electrolyte material or by vitrifying the raw material inorganic composition. This can be achieved by continuously carrying out the steps of annealing and annealing using a crushing device that combines shear stress and compressive stress.

The sulfide-based inorganic solid electrolyte material according to the present embodiment backs the maximum diffraction intensity at the position of diffraction angle 2θ = 35.0 ± 0.1° in the spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. When the ground intensity is _IA and the maximum diffraction intensity of the diffraction peak existing at the diffraction angle 2θ=25.6±0.5° is _IC , the value of _IC / _IA is preferably 2.0 or more. , more preferably 2.5 or more, still more preferably 3.0 or more.
Further, in the sulfide-based inorganic solid electrolyte material according to the present embodiment, the upper limit of the value of I _C /I _A is not particularly limited, but is, for example, 20.0 or less, preferably 15.0 or less, and more preferably 10.0. It is 0 or less, particularly preferably 8.0 or less.
The value of I _C /I _A of the sulfide-based inorganic solid electrolyte material according to the present embodiment can be achieved by adjusting the composition ratio of the sulfide-based inorganic solid electrolyte material.

The sulfide-based inorganic solid electrolyte material according to the present embodiment backs the maximum diffraction intensity at the position of diffraction angle 2θ = 35.0 ± 0.1° in the spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. When the ground intensity is _IA and the maximum diffraction intensity of the diffraction peak existing at the diffraction angle 2θ=29.2±0.8° is _ID , the value of _ID / _IA is preferably 2.0 or more. , more preferably 3.0 or more, still more preferably 4.0 or more, particularly preferably 5.0 or more.
Further, in the sulfide-based inorganic solid electrolyte material according to the present embodiment, the upper limit of the value of I _D /I _A is not particularly limited, but is, for example, 30.0 or less, preferably 15.0 or less, and more preferably 13.0 or less. It is 0 or less, particularly preferably 10.5 or less.
The value of I _D /I _A of the sulfide-based inorganic solid electrolyte material according to the present embodiment can be achieved by adjusting the composition ratio of the sulfide-based inorganic solid electrolyte material.

Moreover, the sulfide-based inorganic solid electrolyte material according to the present embodiment has an additional diffraction peak at the position of the diffraction angle 2θ=26.6±0.4° in the spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. It is preferable to have.
Thereby, lithium ion conductivity can be further improved while maintaining good electrochemical stability.
Although the reason for this is not necessarily clear, the following reasons are inferred.
The sulfide-based inorganic solid electrolyte material, which further has a diffraction peak at the diffraction angle 2θ = 26.6 ± 0.4°, is significantly different from conventional typical sulfide-based inorganic solid electrolyte materials such as Li ₃ PS ₄ . They show different X-ray diffraction profiles (see No. 01-076-0973 of the JCPDS (Joint Committee on Powder Diffraction Standards) card, which is the XRD database of Li ₃ PS ₄ ).
Therefore, the sulfide-based inorganic solid electrolyte material, which has an additional diffraction peak at the diffraction angle 2θ = 26.6 ± 0.4°, has a new structure that is different from conventional sulfide-based inorganic solid electrolyte materials. It is thought that there are. It is thought that such a new structure allows lithium ions to more easily hop. Therefore, the sulfide-based inorganic solid electrolyte material according to the present embodiment has excellent lithium ion diffusivity, and as a result, exhibits higher ionic conductivity than typical sulfide-based inorganic solid electrolyte materials. it is conceivable that.
Therefore, the position of diffraction angle 2θ = 17.2 ± 0.5°, the position of diffraction angle 2θ = 25.6 ± 0.5°, the position of diffraction angle 2θ = 26.6 ± 0.4°, and the position of diffraction angle 2θ = 29 The fact that each of the diffraction peaks is at a position of 0.2±0.8° is considered to indicate that a new structure different from that of conventional typical sulfide-based inorganic solid electrolyte materials is formed.
The above X-ray diffraction profile of the sulfide-based inorganic solid electrolyte material according to the present embodiment can be obtained by adjusting the composition ratio of the sulfide-based inorganic solid electrolyte material, by vitrifying the raw material inorganic composition, and by annealing. It is possible to realize this step by continuously performing the step using a crushing device that combines shear stress and compressive stress.

The sulfide-based inorganic solid electrolyte material according to the present embodiment backs the maximum diffraction intensity at the position of diffraction angle 2θ = 35.0 ± 0.1° in the spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. When the ground intensity is _IA and the maximum diffraction intensity of the diffraction peak existing at the diffraction angle 2θ=26.6±0.4° is _IE , the value of _IE / _IA is preferably 2.2 or more. , more preferably 2.5 or more, still more preferably 3.0 or more, particularly preferably 3.5 or more.
By setting the value of I _E /I _A to be equal to or greater than the above lower limit, lithium ion conductivity can be further improved.
Further, in the sulfide-based inorganic solid electrolyte material according to the present embodiment, the upper limit of the I _E /I _A value is not particularly limited, but is, for example, 15.0 or less, preferably 10.0 or less, and more preferably 8.0 or less. It is 0 or less, even more preferably 6.5 or less, particularly preferably 5.0 or less.
The value of I _E /I _A of the sulfide-based inorganic solid electrolyte material according to the present embodiment can be achieved by adjusting the composition ratio of the sulfide-based inorganic solid electrolyte material.

The sulfide-based inorganic solid electrolyte material according to the present embodiment is designed to further improve lithium ion conductivity, electrochemical stability, stability in moisture and air, and handleability. The molar ratio Li/P of the Li content to the P content in the solid electrolyte material is preferably 1.0 or more and 5.0 or less, more preferably 2.0 or more and 4.0 or less, More preferably, it is 2.5 or more and 3.8 or less, even more preferably 2.8 or more and 3.6 or less, even more preferably 3.0 or more and 3.5 or less, and even more preferably 3. 1 or more and 3.4 or less, particularly preferably 3.1 or more and 3.3 or less, and the molar ratio S/P of the content of S to the content of P is preferably 2.0 or more and 6.0. or less, more preferably 3.0 or more and 5.0 or less, still more preferably 3.5 or more and 4.5 or less, even more preferably 3.8 or more and 4.2 or less, even more preferably 3 .9 or more and 4.1 or less, particularly preferably 4.0.
Here, the contents of Li, P, and S in the sulfide-based inorganic solid electrolyte material according to the present embodiment can be determined by, for example, ICP emission spectrometry or X-ray analysis.

In the sulfide-based inorganic solid electrolyte material according to the present embodiment, lithium ion conduction of the sulfide-based inorganic solid electrolyte material was measured using 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 degree is preferably 2.2×10 ⁻⁴ S・cm ⁻¹ or more, more preferably 3.0×10 ⁻⁴ S・cm ⁻¹ or more, and even more preferably 4.0×10 ⁻⁴ S・cm ^{− 1} or more, particularly preferably 5.0×10 ⁻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 at least the above lower limit, a lithium ion battery with even more excellent battery characteristics can be obtained. Furthermore, by using such a sulfide-based inorganic solid electrolyte material, a lithium ion battery with even better input/output characteristics can be obtained.

The shape of the sulfide-based inorganic solid electrolyte material according to the present embodiment may be, for example, particulate.
The particulate sulfide-based inorganic solid electrolyte material according to the present embodiment is not particularly limited, but preferably has an average particle diameter _d50 of 1 μm or more and 100 μm or less in weight-based particle size distribution measured by laser diffraction scattering particle size distribution measurement method. , more preferably 3 μm or more and 80 μm or less, still more preferably 5 μm or more and 60 μm or less.
By setting the average particle diameter _d50 of the sulfide-based inorganic solid electrolyte material within the above range, good handling properties can be maintained and lithium ion conductivity can be further improved.

The sulfide-based inorganic solid electrolyte material according to this embodiment preferably has excellent electrochemical stability. Here, electrochemical stability refers to, for example, the property of being resistant to redox over a wide voltage range. More specifically, in the sulfide-based inorganic solid electrolyte material according to the present embodiment, the sulfide-based inorganic solid electrolyte material is measured under the conditions of a temperature of 25° C., a sweep voltage range of 0 to 5 V, and a voltage sweep rate of 5 mV/sec. The maximum value of the oxidative decomposition current is preferably 0.50 μA or less, more preferably 0.20 μA or less, even more preferably 0.10 μA or less, and even more preferably 0.05 μA or less. Preferably, it is particularly preferably 0.03 μA or less.
It is preferable that the maximum value of the oxidative decomposition current of the sulfide-based inorganic solid electrolyte material is less than or equal to the above upper limit because oxidative decomposition of the sulfide-based inorganic solid electrolyte material in the lithium ion battery can be suppressed.
The lower limit of the maximum value of the oxidative decomposition current of the sulfide-based inorganic solid electrolyte material is not particularly limited, but is, for example, 0.0001 μA or more.

The sulfide-based inorganic solid electrolyte material according to this embodiment can be used for any purpose requiring lithium ion conductivity. Among these, the sulfide-based inorganic solid electrolyte material according to this embodiment is preferably used for lithium ion batteries. More specifically, it is used for a positive electrode active material layer, a negative electrode active material layer, an electrolyte layer, etc. in a lithium ion battery. Further, the sulfide-based inorganic solid electrolyte material according to the present embodiment is suitably used for a positive electrode active material layer, a negative electrode active material layer, a solid electrolyte layer, etc. that constitute an all-solid-state lithium ion battery, and is suitable for all-solid-state lithium ion batteries. It is particularly suitable for use in solid electrolyte layers constituting batteries.
An example of an all-solid-state lithium ion battery to which the sulfide-based inorganic solid electrolyte material according to the present embodiment is applied is one in which a positive electrode, a solid electrolyte layer, and a negative electrode are stacked in this order.

[Method for producing sulfide-based inorganic solid electrolyte material]
Next, a method for manufacturing the sulfide-based inorganic solid electrolyte material according to the present embodiment will be described.
The method for manufacturing a sulfide-based inorganic solid electrolyte material according to this embodiment is different from the conventional method for manufacturing a sulfide-based inorganic solid electrolyte material. In other words, a sulfide-based inorganic solid electrolyte material that generates hydrogen sulfide in an amount below the above upper limit requires (1) highly controlled composition ratio of the sulfide-based inorganic solid electrolyte material, and (2) inorganic raw material. We have developed innovative manufacturing methods such as continuously performing the vitrification process and annealing process of the composition, and applying stronger shear and compressive forces than before to produce a sulfide-based inorganic solid electrolyte material. You can only get it by adopting it.
However, the sulfide-based inorganic solid electrolyte material according to this embodiment is based on the premise that the above two manufacturing methods are adopted, and the specific manufacturing conditions, such as the mixing conditions of various raw materials, are various. can be adopted.
Hereinafter, the method for manufacturing the sulfide-based inorganic solid electrolyte material according to the present embodiment will be described in more detail.

The sulfide-based inorganic solid electrolyte material according to the present embodiment can be obtained, for example, by a manufacturing method including the following steps (A), (B), and (C). Further, the method for producing a sulfide-based inorganic solid electrolyte material according to the present embodiment may further include the following steps (D) and (E) as necessary.
Step (A): Step of preparing a raw material inorganic composition containing two or more types of inorganic compounds as raw materials. Step (B): Mechanically crushing the raw material inorganic composition using a crushing device that combines shear stress and compressive stress. A step of vitrifying raw inorganic compounds while chemically reacting with each other to obtain a sulfide-based inorganic solid electrolyte material in a glass state. Step (C) Using the above-mentioned crushing device that combines shear stress and compressive stress. Step (D): A step of annealing the sulfide-based inorganic solid electrolyte material in a glass state by mechanical treatment to crystallize at least a part of the material. Step (D): A step of combining the preparation step (A) and the vitrification step (B) In the meantime, a step of crystallizing the raw material inorganic composition by heating the raw material inorganic composition prepared in step (A).Step (E): The obtained sulfide-based inorganic solid electrolyte material is pulverized, classified, or Granulation process

According to the method for producing a sulfide-based inorganic solid electrolyte material according to the present embodiment, the vitrification step (B) and the annealing treatment step (C) are continuously performed using a crushing device that combines shear stress and compressive stress. Because of this, it is possible to apply strong shear stress and compressive stress to the inorganic composition compared to conventional manufacturing methods, making it possible to more effectively generate frictional heat between the particles that make up the inorganic composition. . Therefore, according to the method for manufacturing a sulfide-based inorganic solid electrolyte material according to the present embodiment, heat can be transmitted more effectively to the sulfide-based inorganic solid electrolyte material in a glass state, and as a result, heat can be transmitted more effectively to the sulfide-based inorganic solid electrolyte material in a glass state. It is believed that a sulfide-based inorganic solid electrolyte material with a new structure different from that of the previous one has been realized.

(Step (A) of preparing raw material inorganic composition)
First, a raw material inorganic composition containing two or more kinds of inorganic compounds such as lithium sulfide, phosphorus sulfide, and lithium nitride in a specific ratio is prepared. Here, the mixing ratio of each raw material in the raw material inorganic composition is adjusted so that the obtained sulfide-based inorganic solid electrolyte material has a desired composition ratio.
The method of mixing each raw material is not particularly limited as long as it can mix each raw material uniformly, but examples include crushers, ball mills, bead mills, vibration mills, impact crushers, mixers (pug mixers, ribbon mixers, tumbler mixers , a drum mixer, a V-type mixer, etc.), a kneader, a twin-screw kneader, an air flow mill, and the like.
Mixing conditions such as stirring speed, processing time, temperature, reaction pressure, and gravitational acceleration applied to the mixture when mixing each raw material can be appropriately determined depending on the amount of the mixture to be processed.

The lithium sulfide used as a raw material is not particularly limited, and commercially available lithium sulfide may be used, or, for example, lithium sulfide obtained by a reaction between lithium hydroxide and hydrogen sulfide may be used. From the viewpoint of obtaining a highly pure sulfide-based inorganic solid electrolyte material and 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 (for example, P ₂ S ₅ , P ₄ S ₃ , P ₄ S ₇ , P ₄ S ₅ , etc.) can be used. From the viewpoint of obtaining a highly pure sulfide-based inorganic solid electrolyte material and suppressing side reactions, it is preferable to use phosphorus sulfide with few impurities. Moreover, in place of phosphorus sulfide, elemental phosphorus (P) and elemental sulfur (S) in corresponding molar ratios can also be used. Elemental phosphorus (P) and elemental 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. Here, since the nitrogen in lithium nitride is discharged into the system as _N2 , by using lithium nitride as the raw material inorganic compound, a sulfide-based inorganic solid containing Li, P, and S as constituent elements can be produced. It becomes possible to increase only the Li composition in the electrolyte material.
The lithium nitride according to the present embodiment is not particularly limited, and commercially available lithium nitride (for example, Li ₃ N, etc.) may be used, or for example, lithium metal (for example, Li foil) and nitrogen gas may be used. Lithium nitride obtained by the reaction may also be used. From the viewpoint of obtaining a highly pure solid electrolyte material and suppressing side reactions, it is preferable to use lithium nitride with few impurities.

(Vitrification process (B) and annealing process (C))
Next, the raw inorganic composition is mechanically treated using a crushing device that combines shear stress and compressive stress, thereby vitrifying the inorganic composition while causing a chemical reaction between two or more of the inorganic compounds. Perform the vitrification step (B). Next, following this vitrification step (B), the sulfide-based inorganic solid electrolyte material in the glass state is annealed by mechanical treatment using the crushing device used in the vitrification step (B) as it is, An annealing treatment step (C) for crystallizing at least a portion is performed.
That is, in the method for producing a sulfide-based inorganic solid electrolyte material according to the present embodiment, the vitrification step (B) and the annealing step (C) are continuously performed using a crushing device that combines shear stress and compressive stress. Let's do it. Here, the vitrification process (B) and the annealing process (C) do not need to be clearly distinguished, and may gradually change from the vitrification process (B) to the annealing process (C). included.

In the vitrification step (B) in the method for producing a sulfide-based inorganic solid electrolyte material according to the present embodiment, the inorganic composition is mechanically treated using a crushing device that combines shear stress and compressive stress. A sulfide-based inorganic solid electrolyte material is vitrified while chemically reacting one or more inorganic compounds. Even after the inorganic composition is vitrified, mechanical treatment using this crushing device is continuously performed, and the vitrified sulfide-based inorganic solid electrolyte material is annealed. Here, if shear stress and compressive stress are continuously applied to the vitrified sulfide-based inorganic solid electrolyte material using a crushing device that combines shear stress and compressive stress, the sulfide-based inorganic solid electrolyte material The vitrified sulfide-based inorganic solid electrolyte material is heated by the frictional heat between the constituent particles, and as a result, the vitrified sulfide-based inorganic solid electrolyte material is annealed and partially crystallized. That is, in the annealing treatment step (C) in the method for producing a sulfide-based inorganic solid electrolyte material according to the present embodiment, shear stress and compressive stress generated when applying shear stress and compressive stress to the vitrified sulfide-based inorganic solid electrolyte material The vitrified sulfide-based inorganic solid electrolyte material can be annealed by heat.
By performing the annealing treatment step (C), at least a portion of the vitrified sulfide-based inorganic solid electrolyte material can be crystallized to form a sulfide-based inorganic solid electrolyte material in a glass ceramic state.

The heating temperature of the vitrified sulfide-based inorganic solid electrolyte material in the annealing treatment step (C) is preferably in the range of 200°C or more and 500°C or less, and preferably in the range of 220°C or more and 350°C or less. is more preferable.

In the annealing treatment step (C), mechanical treatment is performed until a diffraction peak different from that of the vitrified sulfide-based inorganic solid electrolyte material is observed in the spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. It is preferable. Here, the fact that a diffraction peak different from that of the vitrified sulfide-based inorganic solid electrolyte material is observed indicates that at least a portion of the vitrified sulfide-based inorganic solid electrolyte material has crystallized and is in a glass-ceramic state. It is thought to mean that there is.

The mechanical treatment in the vitrification step (B) and the annealing step (C) includes vitrifying the inorganic composition while causing a chemical reaction by mechanically colliding two or more of the inorganic compounds, The vitrified inorganic composition can be subjected to an annealing treatment, such as mechanochemical treatment. Here, the mechanochemical treatment is a method of applying mechanical energy such as shear force or collision force to the target composition.

In the vitrification step (B) and the annealing step (C), the mechanical treatment is preferably carried out in a dry manner. This eliminates the need for an operation to remove liquid components such as organic solvents from the vitrified sulfide-based inorganic solid electrolyte material, and the productivity of the sulfide-based inorganic solid electrolyte material can be further improved. Further, reaction between the sulfide-based inorganic solid electrolyte material and the organic solvent can be prevented. Furthermore, since no liquid components such as organic solvents are used, safety in the manufacturing process can be further improved.

Examples of crushing devices that combine shear stress and compressive stress according to this embodiment include roll mills; Examples include a rotating/impact crushing device consisting of a mechanism; a high-pressure gliding roll; and a vertical mill such as a roller-type vertical mill and a ball-type vertical mill. Among these, from the viewpoint of excellent continuous productivity, roll mills and vertical mills are preferred, and roll mills are more preferred.

Further, it is preferable that the roll mill according to this embodiment is constituted by three or more rolls. As a result, the vitrification treatment and the annealing treatment can be performed more continuously, so that the productivity of the obtained sulfide-based inorganic solid electrolyte material can be further improved.

Further, the diameter of the rolls constituting the roll mill according to this embodiment is preferably 40 mm or more, more preferably 50 mm or more, and even more preferably 60 mm or more. As a result, even stronger shear stress and compressive stress can be applied to the raw material inorganic composition present between the rolls, so that the vitrification of the raw material inorganic composition can be further efficiently performed. Furthermore, it is possible to apply even stronger shear stress and compressive stress to the vitrified sulfide-based inorganic solid electrolyte material that exists between the rolls, so the frictional heat generated by the particles that make up the sulfide-based inorganic solid electrolyte material can be generated more effectively, and as a result, it becomes possible to proceed with the annealing treatment of the vitrified sulfide-based inorganic solid electrolyte material more effectively.

Further, in the roll mill according to this embodiment, it is preferable that the rotational speeds of adjacent rolls are different. Thereby, shear stress can be applied more effectively to the inorganic composition existing between the rolls while applying compressive stress, so that the vitrification of the raw material inorganic composition can be further efficiently performed.
Further, in the roll mill according to this embodiment, it is preferable that adjacent rolls rotate in different directions. Thereby, compressive stress can be applied more effectively to the inorganic composition present between the rolls.

It is preferable that at least the surface of the roll constituting the roll mill according to this embodiment is made of at least one kind of material selected from ceramic materials and metal materials.
Examples of the metal material include centrifugally chilled steel, SUS, Cr-plated SUS, and Cr-plated hardened steel.
Furthermore, when at least the surface of the rolls constituting the roll mill according to the present embodiment is made of a ceramic material, it is possible to suppress unnecessary metal components derived from the rolls from being mixed into the obtained sulfide-based inorganic solid electrolyte material. This makes it possible to obtain a sulfide-based inorganic solid electrolyte material with even higher purity.
Examples of such ceramic materials include stabilized zirconia, alumina, silicon carbide, and silicon nitride.
Among these, alumina is preferable because it is relatively inexpensive and can produce highly accurate large parts.

Hereinafter, a case will be specifically described in which the vitrification step (B) and the annealing step (C) according to the present embodiment are performed using a three-roll mill consisting of three rolls as a crushing device.
A three-roll mill, for example, is composed of a first roll, a second roll, a third roll, and blades.
First, a raw inorganic composition containing two or more types of inorganic compounds is placed between the first roll and the second roll.
The raw inorganic composition that has entered between the first rolls is compressed by the first roll and the second roll. Here, by employing different rotational speeds for the first roll and the second roll, we can more effectively apply shear stress to the raw inorganic composition that has entered between the first rolls while applying compressive stress. Therefore, the vitrification and annealing treatment of the inorganic composition can proceed more efficiently.

Here, the rotational speed of the rolls is preferably faster for the second roll than the first roll, and faster for the third roll than the second roll. That is, in the roll mill according to the present embodiment, the number of rotations of the plurality of rolls is set to gradually increase from the roll where the inorganic composition is introduced to the roll where the inorganic composition is discharged. Preferably. The rotational speed of each roll is appropriately determined depending on the number of rolls, the type of inorganic composition, the amount of inorganic composition processed, etc., and is not particularly limited. In this case, if the speed of the first roll is 1, the speed of the second roll is 2 to 4, and the speed of the third roll is 5 to 9. can do. By doing this, the inorganic composition attached to the roll can be transferred to the surface of the adjacent roll more efficiently, and as a result, the productivity of the sulfide-based inorganic solid electrolyte material can be further improved. .

Next, after passing the inorganic composition between the first rolls, the inorganic composition is passed between the second rolls adjacent to the first rolls. By repeating this operation, the inorganic composition can be vitrified and annealed continuously. Here, the inorganic composition is adhered to the surface of the second roll due to the compressive stress caused by the first roll and the second roll, so it is possible to continuously transfer it between the second rolls. .
The sulfide-based inorganic solid electrolyte material obtained by passing between the second rolls is attached to the surface of the third roll, and can be scraped off with a blade, for example.
In addition, if the sulfide-based inorganic solid electrolyte material obtained by passing between the second rolls is insufficiently vitrified or annealed, the above-mentioned method of passing between the first rolls and between the second rolls may be applied. It is preferable to repeat the process. Alternatively, it is preferable that the number of rolls in the roll mill is four or more, and mechanical treatment using a combination of shear stress and compressive stress is further performed.

Here, in the roll mill according to the present embodiment, from the viewpoint of applying compressive stress to the inorganic composition more effectively, the distance between the rolls is preferably 1 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.
Further, in the roll mill according to the present embodiment, from the viewpoint of applying shear stress to the inorganic composition more effectively, the rotational speed of the roll is preferably 20 rpm or more and 1000 rpm or less, and more preferably 100 rpm or more and 800 rpm or less.
However, the distance between the rolls and the rotational speed of the rolls are appropriately determined depending on the type and amount of the inorganic composition to be treated, the number of rolls, etc., and therefore are not limited to the above ranges.

Furthermore, it is preferable that the mechanical treatments in the vitrification step (B) and the annealing step (C) be performed in an inert atmosphere. Thereby, the reaction between the inorganic composition and water vapor, oxygen, etc. can be suppressed.
Moreover, the above-mentioned under an inert atmosphere means under a vacuum atmosphere or under an inert gas atmosphere. Under the above-mentioned inert atmosphere, the dew point is preferably −50° C. or lower, more preferably −60° C. or lower to avoid contact with moisture. The above inert gas atmosphere refers to an atmosphere of an inert gas such as argon gas, helium gas, nitrogen gas, or the like. The higher the purity of these inert gases, the more preferable they are in order to prevent impurities from being mixed into the product. The method of introducing inert gas into the mixed system is not particularly limited as long as the inside of the mixed system is filled with an inert gas atmosphere, but methods include purging the inert gas, and continuously introducing a certain amount of inert gas. Examples include methods.

Mixing conditions such as rotation speed, processing time, temperature, etc. when vitrifying the above raw material inorganic composition or annealing the vitrified sulfide-based inorganic solid electrolyte material depend on the type of inorganic composition and the amount of processing. It can be determined as appropriate. In general, the faster the rotation speed, the faster the glass formation rate, so the time for the vitrification step (B) becomes shorter, and the higher the temperature of the sulfide-based inorganic solid electrolyte material, the annealing step (C). ) will be shorter.
Normally, when performing X-ray diffraction analysis using CuKα rays as a radiation source, if the diffraction peak of the inorganic composition before the vitrification step (B) disappears or decreases, the inorganic composition is vitrified. It can be determined that the In addition, when performing X-ray diffraction analysis using CuKα rays as a radiation source, the inorganic composition before the vitrification step (B) and the sulfide-based inorganic solid before the annealing step (C) are usually analyzed. If a new diffraction peak different from the diffraction peak of the electrolyte material is generated, it can be determined that the inorganic composition has been annealed and is in a glass-ceramic state.

(Crystallization step (D))
In the method for producing a sulfide-based inorganic solid electrolyte material according to the present embodiment, between the preparation step (A) and the vitrification step (B), the raw material inorganic composition prepared in step (A) is heated. You may further perform the process of crystallizing a raw material inorganic composition by.
That is, the vitrification step (B) may be performed on the crystallized raw material inorganic composition.
By performing the crystallization step (D) before the vitrification step (B), the step (B) of vitrifying the raw inorganic composition can be significantly shortened, and as a result, the sulfide-based inorganic solid It is possible to further shorten the manufacturing time of electrolyte materials. Although the reason for this is not clear, the following reasons are inferred.
First, an inorganic composition in a glass state is in a metastable state. On the other hand, an inorganic composition in a crystalline state is in a stable state. In addition, when an inorganic composition containing two or more types of inorganic compounds is heated, energy exceeding the activation energy can be easily applied, so that the inorganic composition in a crystalline state, which is in a low energy state, quickly changes as energy is released. can get. Since the free energy of the stable state and the free energy of the metastable state are close, it is possible to change from the stable crystalline state to the metastable glass state with lower energy.
For the above reasons, before the step (B) of vitrifying the inorganic composition, the step (D) of crystallizing the inorganic composition is performed to bring the inorganic composition into a stable crystalline state in advance. It is thought that it is possible to bring the inorganic composition into a metastable glass state with less energy, and the process of vitrifying the inorganic composition can be significantly shortened.

The temperature at which the inorganic composition is heated is not particularly limited, but for example, the heating temperature is preferably in the range of 200°C or more and 400°C or less, and preferably in the range of 220°C or more and 300°C or less. More preferred.

The time for heating the inorganic composition is not particularly limited as long as it is a time that can crystallize the inorganic composition, but for example, it is within the range of 1 minute to 24 hours, preferably 0.1 The duration is between 10 hours and 10 hours. Although the heating method is not particularly limited, for example, a method using a firing furnace can be mentioned. Note that conditions such as temperature and time for heating can be adjusted as appropriate in order to optimize the characteristics of the sulfide-based inorganic solid electrolyte material of this embodiment.

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

(Crushing, classifying, or granulating step (E))
In the method for producing a sulfide-based inorganic solid electrolyte material of the present 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 size can be obtained by pulverizing the material into fine particles and then adjusting the particle size using a classification operation or a granulation operation. The above-mentioned pulverization method is not particularly limited, and known pulverization methods such as a mixer, air flow pulverization, mortar, rotary mill, and coffee mill can be used. Moreover, the above-mentioned classification method is not particularly limited, and known methods such as sieving can be used.
These pulverizations or classifications are preferably performed under an inert gas atmosphere or a vacuum atmosphere from the viewpoint of preventing contact with moisture in the air.

[Solid electrolyte]
Next, the solid electrolyte according to this embodiment will be explained. The solid electrolyte according to this embodiment includes the sulfide-based inorganic solid electrolyte material according to this embodiment.
The solid electrolyte according to this embodiment is not particularly limited, but as a component other than the sulfide-based inorganic solid electrolyte material according to this embodiment, for example, the above-mentioned embodiment The solid electrolyte material may contain a different type of solid electrolyte material from the sulfide-based inorganic solid electrolyte material.

The solid electrolyte according to this embodiment may include a different type of solid electrolyte material from the sulfide-based inorganic solid electrolyte material according to this embodiment described above. Solid electrolyte materials of a type different from the sulfide-based inorganic solid electrolyte material according to the present embodiment are not particularly limited as long as they have ionic conductivity and insulation properties, but materials commonly used in lithium ion batteries are used. can be used. For example, inorganic solid electrolyte materials such as sulfide-based inorganic solid electrolyte materials, oxide-based inorganic solid electrolyte materials, and other lithium-based inorganic solid electrolyte materials different from the sulfide-based inorganic solid electrolyte materials according to the present embodiment; Organic solid electrolyte materials such as polymer electrolytes can be mentioned.

Examples of sulfide-based inorganic solid electrolyte materials different from the sulfide-based inorganic solid electrolyte material according to the present embodiment described above include Li ₂ S-P ₂ S ₅ material, Li ₂ S-SiS ₂ material, and Li ₂ S. -GeS ₂ material, Li ₂ S-Al ₂ S ₃ material, Li ₂ S-SiS ₂ -Li ₃ PO ₄ material, Li ₂ S-P ₂ S _{5 -} GeS ₂ material, Li ₂ S-Li ₂ O-P ₂ S ₅ -SiS ₂ material, Li ₂ S-GeS ₂ -P ₂ S ₅ -SiS ₂ material, Li ₂ S-SnS ₂ -P ₂ S ₅ -SiS ₂ material, Li ₂ S-P ₂ S ₅ -Li _3N material, Li ₂ S _2+X -P ₄ S ₃ material, Li ₂ SP ₂ S ₅ -P ₄ S ₃ material, etc. These may be used alone or in combination of two or more.
Among these, Li ₂ SP ₂ S ₅ material is preferred because it has excellent lithium ion conductivity and stability that does not cause decomposition over a wide voltage range. Here, for example, the Li ₂ S-P ₂ S ₅ material is a solid obtained by chemically reacting an inorganic composition containing at least Li ₂ S (lithium sulfide) and P ₂ S ₅ with each other through mechanical treatment. means electrolyte material.
Here, in this embodiment, lithium sulfide also includes lithium polysulfide.

Examples of the oxide-based inorganic solid electrolyte materials include NASICON type materials such as LiTi ₂ (PO ₄ ) ₃ , LiZr ₂ (PO ₄ ) ₃ , LiGe ₂ (PO ₄ ) ₃ , (La _0.5+x Li _{0.5 -3x} ) Perovskite type materials such as TiO ₃ , Li ₂ O--P ₂ O ₅ materials, Li ₂ O--P ₂ O ₅ --Li ₃ N materials, and the like.
Examples of other lithium-based inorganic solid electrolyte materials include LiPON, LiNbO ₃ , LiTaO ₃ , Li ₃ PO ₄ , LiPO _4-x N _x (x is 0<x≦1), LiN, LiI, LISICON, etc. It will be done.
Furthermore, glass ceramics obtained by depositing crystals of these inorganic solid electrolytes can also be used as the inorganic solid electrolyte material.

As the organic solid electrolyte material, for example, a polymer electrolyte such as a dry polymer electrolyte or a gel electrolyte can be used.
As the polymer electrolyte, those commonly used in lithium ion batteries can be used.

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

The solid electrolyte membrane 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 to which the solid electrolyte membrane according to the present embodiment is applied is one in which a positive electrode, a solid electrolyte layer, and a negative electrode are stacked in this order. In this case, the solid electrolyte layer is composed 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 lower limit, it is possible to further suppress loss of the solid electrolyte and generation of cracks on the surface of the solid electrolyte membrane. Further, when the average thickness of the solid electrolyte membrane is equal to or less than the upper limit value, the impedance of the solid electrolyte membrane can be further reduced. 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 press-molded particulate solid electrolyte containing the sulfide-based inorganic solid electrolyte material according to the present embodiment described above. That is, it is preferable to pressurize the particulate solid electrolyte to form a solid electrolyte membrane having a certain strength due to the anchoring effect between the solid electrolyte materials.
By forming a pressure-molded body, the solid electrolytes are bonded to each other, and the strength of the obtained solid electrolyte membrane is further increased. As a result, the loss of the solid electrolyte and the occurrence of cracks on the surface of the solid electrolyte membrane 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 50% by mass or more, and more preferably 50% by mass or more when the entire solid electrolyte membrane is 100% by mass. Preferably it is 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more. This improves the contact between the solid electrolytes 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. By using such a solid electrolyte membrane with excellent lithium ion conductivity, the battery characteristics of the obtained all-solid-state lithium ion battery can be further improved.
The upper limit of the content of the sulfide-based inorganic solid electrolyte material according to the present embodiment described above in the solid electrolyte membrane according to the present embodiment is not particularly limited, but is, for example, 100% by mass or less.

The planar shape of the solid electrolyte membrane is not particularly limited and can be appropriately selected according to the shapes of the electrodes and current collectors, and may be rectangular, for example.

Further, the solid electrolyte membrane according to the present 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 0.1% by mass or less, still more preferably 0.05% by mass or less, even more preferably 0.01% by mass or less. Moreover, it is even more preferable that the solid electrolyte membrane according to this embodiment does not substantially contain binder resin, and most preferably that it does not contain binder resin.
This improves the contact between the solid electrolytes 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. 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.
Note that "substantially no binder resin is contained" means that the binder resin may be contained to the extent that the effects of the present embodiment are not impaired. In addition, when providing an adhesive resin layer between the solid electrolyte layer and the positive electrode or the negative electrode, the adhesive resin derived from the adhesive resin layer existing near the interface between the solid electrolyte layer and the adhesive resin layer is removed from the binder resin in the film.

The above binder resin refers to a binder commonly used in lithium ion batteries to bind inorganic solid electrolyte materials, such as polyvinyl alcohol, polyacrylic acid, carboxymethylcellulose, polytetrafluorocarbon Examples include ethylene, polyvinylidene fluoride, styrene-butadiene rubber, and polyimide.

The solid electrolyte membrane according to the present embodiment is produced by, for example, depositing particulate solid electrolyte in a film shape on the cavity surface of a mold or on the base material surface, and then pressurizing the solid electrolyte deposited in the film shape. Obtainable.
The method of pressurizing the solid electrolyte is not particularly limited, and for example, if the particulate solid electrolyte is deposited on the cavity surface of a mold, pressing with a mold and a press die, or pressing the particulate solid electrolyte onto the base material surface. When deposited on top, pressing using a die and a press, roll press, flat plate press, etc. can be used.
The pressure to pressurize the solid electrolyte is, for example, 10 MPa or more and 500 MPa or less.

Further, if necessary, the inorganic solid electrolyte deposited in the form of a film may be pressurized and heated. By heating and pressurizing, the solid electrolytes 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 solid electrolyte and the occurrence of cracks on the surface of the solid electrolyte membrane can be further suppressed.
The temperature at which the solid electrolyte is heated is, for example, 40° C. or higher and 500° C. or lower.

[Lithium ion battery]
FIG. 1 is a cross-sectional view showing an example of the structure of a lithium ion battery 100 according to an embodiment of the present invention.
The lithium ion battery 100 according to the present embodiment includes, for example, a positive electrode 110 including a positive electrode active material layer 101, an electrolyte layer 120, and a negative electrode 130 including a negative electrode active material layer 103. At least one of the positive electrode active material layer 101, the negative electrode active material layer 103, and the electrolyte layer 120 contains the sulfide-based inorganic solid electrolyte material according to the present embodiment. Further, it is preferable that all of the positive electrode active material layer 101, the negative electrode active material layer 103, and the electrolyte layer 120 contain the sulfide-based inorganic solid electrolyte material according to the present embodiment. Note that in this embodiment, unless otherwise specified, a layer containing a positive electrode active material is referred to as a positive electrode active material layer 101. The positive electrode 110 may further include a current collector 105 in addition to the positive electrode active material layer 101, or may not include the current collector 105, as necessary. Furthermore, in this embodiment, unless otherwise specified, a layer containing a negative electrode active material is referred to as a negative electrode active material layer 103. Negative electrode 130 may further include current collector 105 in addition to negative electrode active material layer 103, or may not include current collector 105, as necessary.
The shape of the lithium ion battery 100 according to this embodiment 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 lithium ion battery 100 according to this embodiment is manufactured according to a generally known method. For example, by forming a stack of the positive electrode 110, electrolyte layer 120, and negative electrode 130 into a cylindrical shape, a coin shape, a square shape, a film shape, or any other arbitrary shape, and enclosing a nonaqueous electrolyte as necessary, Created.

(positive electrode)
The positive electrode 110 is not particularly limited, and those commonly used for lithium ion batteries can be used. Although the positive electrode 110 is not particularly limited, it can be manufactured according to a generally known method. For example, it can be obtained by forming a positive electrode active material layer 101 containing a positive electrode active material on the surface of a current collector 105 such as aluminum foil.
The thickness and density of the positive electrode active material layer 101 are appropriately determined depending on the intended use of the battery and are not particularly limited, and can be set according to generally known information.

The positive electrode active material layer 101 contains a positive electrode active material.
The positive electrode active material is not particularly limited, and generally known materials 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.) ), composite oxides such as lithium-manganese-nickel oxide (LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ), and olivine-type lithium phosphate oxide (LiFePO ₄ ); highly conductive materials such as polyaniline and polypyrrole Molecule; Li ₂ S, CuS, Li-Cu-S compound, TiS ₂ , FeS, MoS ₂ , Li-Mo-S compound, Li-Ti-S compound, Li-V-S compound, Li-Fe-S compound Sulfide-based positive electrode active materials such as sulfide-based positive electrode active materials; materials containing sulfur as an active material such as sulfur-impregnated acetylene black, sulfur-impregnated porous carbon, and mixed powder of sulfur and carbon; etc. can be used. 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 higher discharge capacity density and better cycle characteristics, and Li-Mo-S compounds, Li-Ti-S compounds, Li-V-S One or more types selected from the compounds are more preferable.

Here, the Li-Mo-S compound contains Li, Mo, and S as constituent elements, and usually an inorganic composition containing the raw materials molybdenum sulfide and lithium sulfide is chemically bonded to each other by mechanical treatment. It can be obtained by reaction.
In addition, Li-Ti-S compounds contain Li, Ti, and S as constituent elements, and are usually produced by chemically reacting the raw materials titanium sulfide and inorganic composition containing lithium sulfide with each other through mechanical treatment. It can be obtained by
Li-V-S compounds contain Li, V, and S as constituent elements, and are usually made by mechanically treating inorganic compositions containing vanadium sulfide and lithium sulfide as raw materials to chemically react with each other. It can be obtained by

Although the positive electrode active material layer 101 is not particularly limited, it may include, for example, one or more materials selected from a binder resin, a thickener, a conductive aid, a solid electrolyte material, etc. as a component other than the positive electrode active material. . Each material will be explained below.

The positive electrode active material layer 101 may include a binder resin that serves to bind the positive electrode active materials to each other and to bind the positive electrode active material and the current collector 105.
The binder resin according to this embodiment is not particularly limited as long as it is a normal binder resin that can be used in lithium ion batteries, but examples include polyvinyl alcohol, polyacrylic acid, carboxymethyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride, styrene, etc. Examples include butadiene rubber and polyimide. These binders may be used alone or in combination of two or more.

The positive electrode active material layer 101 may contain a thickener in order to ensure fluidity of the slurry suitable for coating. The thickener is not particularly limited as long as it is a normal thickener that can be used in lithium ion batteries, but examples include cellulose polymers such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose, and ammonium salts and alkali metal salts thereof; Examples include water-soluble polymers such as polycarboxylic acid, polyethylene oxide, polyvinylpyrrolidone, polyacrylate, and polyvinyl alcohol. These thickeners may be used alone or in combination of two or more.

The positive electrode active material layer 101 may contain a conductive additive from the viewpoint of improving the conductivity of the positive electrode 110. The conductive aid is not particularly limited as long as it is a normal conductive aid that can be used in lithium ion batteries, but examples include carbon black such as acetylene black and Ketjen black, and carbon materials such as vapor grown carbon fiber. .

The positive electrode according to the present embodiment may include a solid electrolyte containing the sulfide-based inorganic solid electrolyte material according to the present embodiment described above, or may include a solid electrolyte containing the sulfide-based inorganic solid electrolyte material according to the present embodiment. A solid electrolyte containing a solid electrolyte material may be included. Solid electrolyte materials of a type different from the sulfide-based inorganic solid electrolyte material according to the present embodiment are not particularly limited as long as they have ionic conductivity and insulation properties, but materials commonly used in lithium ion batteries are used. can be used. Examples include inorganic solid electrolyte materials such as sulfide-based inorganic solid electrolyte materials, oxide-based inorganic solid electrolyte materials, and other lithium-based inorganic solid electrolyte materials; and organic solid electrolyte materials such as polymer electrolytes. More specifically, the inorganic solid electrolyte materials mentioned in the description of the solid electrolyte according to this embodiment can be used.

The blending ratios of various materials in the positive electrode active material layer 101 are appropriately determined depending on the intended use of the battery, and are not particularly limited, and can be set according to generally known information.

(Negative electrode)
The negative electrode 130 is not particularly limited, and those commonly used for lithium ion batteries can be used. Although the negative electrode 130 is not particularly limited, it can be manufactured according to a generally known method. For example, it can be obtained by forming a negative electrode active material layer 103 containing a negative electrode active material on the surface of a current collector 105 made of copper or the like.
The thickness and density of the negative electrode active material layer 103 are appropriately determined depending on the intended use of the battery and are not particularly limited, and can be set according to generally known information.

Negative electrode active material layer 103 contains a negative electrode active material.
The above-mentioned negative electrode active material is not particularly limited as long as it is a normal negative electrode active material that can be used for negative electrodes of lithium ion batteries, but examples include natural graphite, artificial graphite, resin charcoal, carbon fiber, activated carbon, hard carbon, and soft carbon. Carbonaceous materials such as lithium, lithium alloys, tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, aluminum alloys, etc. Metallic materials such as polyacene, polyacetylene, polypyrrole, etc. conductive polymer; lithium titanium composite oxide (for example, Li ₄ Ti ₅ O ₁₂ ), and the like. These negative electrode active materials may be used alone or in combination of two or more.

Although the negative electrode active material layer 103 is not particularly limited, it may include, for example, one or more materials selected from a binder resin, a thickener, a conductive aid, a solid electrolyte material, etc. as a component other than the negative electrode active material. . These materials are not particularly limited, but may include, for example, the same materials as those used for the positive electrode 110 described above.
The blending ratios of various materials in the negative electrode active material layer 103 are appropriately determined depending on the intended use of the battery and are not particularly limited, and can be set according to generally known information.

(electrolyte layer)
Next, the electrolyte layer 120 will be explained. Electrolyte layer 120 is a layer formed between positive electrode active material layer 101 and negative electrode active material layer 103.
Examples of the electrolyte layer 120 include a separator impregnated with a nonaqueous electrolyte and a solid electrolyte layer containing a solid electrolyte.

The separator according to the present embodiment is not particularly limited as long as it has the function of electrically insulating the positive electrode 110 and the negative electrode 130 and transmitting lithium ions, but for example, a porous membrane can be used.

A microporous polymer film is preferably used as the porous membrane, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, polyester, and the like. In particular, porous polyolefin films are preferred, and specific examples include porous polyethylene films and porous polypropylene films.

The above-mentioned non-aqueous electrolyte is one in which an electrolyte is dissolved in a solvent.
As the electrolyte, any known lithium salt can be used, and the electrolyte may be selected depending on the type of active material. _For example, _LiClO4 , _LiBF6 , _LiPF6 , _LiCF3SO3 , _LiCF3CO2 , _LiAsF6 , _{LiSbF6 , LiB10Cl10} , _{LiAlCl4 ,} LiCl, _LiBr , LiB( _C2H5 ) ₄ , CF ₃ Examples include SO ₃ Li, CH ₃ SO ₃ Li, LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, and lithium lower fatty acid carboxylate.

The solvent for dissolving the electrolyte is not particularly limited as long as it is a liquid commonly used as a liquid for dissolving electrolytes, and examples include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and dimethyl carbonate (DMC). , carbonates such as diethyl carbonate (DEC), methyl ethyl carbonate (MEC), and vinylene carbonate (VC); lactones such as γ-butyrolactone and γ-valerolactone; trimethoxymethane, 1,2-dimethoxyethane, diethyl ether , 2-ethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran and other ethers; dimethylsulfoxide and other sulfoxides; 1,3-dioxolane and 4-methyl-1,3-dioxolane and other oxolanes; acetonitrile, nitromethane, formamide, Nitrogen-containing compounds such as dimethylformamide; organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and ethyl propionate; phosphoric acid triesters and diglymes; triglymes; sulfolane, methylsulfolane, etc. Oxazolidinones such as 3-methyl-2-oxazolidinone; Sultones such as 1,3-propane sultone, 1,4-butane sultone, and naphtha sultone; and the like. These may be used alone or in combination of two or more.

The solid electrolyte layer according to this embodiment is a layer formed between the positive electrode active material layer 101 and the negative electrode active material layer 103, and is a layer formed of a solid electrolyte containing a solid electrolyte material. The solid electrolyte contained in the solid electrolyte layer is not particularly limited as long as it has lithium ion conductivity, but in this embodiment, a solid electrolyte containing the sulfide-based inorganic solid electrolyte material according to this embodiment is used. Preferably it is an electrolyte.
The content of the solid electrolyte in the solid electrolyte layer according to the present embodiment is not particularly limited as long as the desired insulation property is obtained; Among these, it is preferably within the range of 50 volume % or more and 100 volume % or less. In particular, in this embodiment, it is preferable that the solid electrolyte layer is composed only of a solid electrolyte containing the sulfide-based inorganic solid electrolyte material according to this embodiment.

Moreover, the solid electrolyte layer according to this embodiment may contain a binder resin. By containing the binder resin, a solid electrolyte layer having flexibility can be obtained. Examples of the binder resin include fluorine-containing binders such as polytetrafluoroethylene and polyvinylidene fluoride. The thickness of the solid electrolyte layer is, for example, preferably in the range of 0.1 μm or more and 1000 μm or less, and particularly preferably in the range of 0.1 μm or more and 300 μm or less.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above may also be adopted.
Note that the present invention is not limited to the above-described embodiments, and the present invention includes modifications, improvements, etc. within a range that can achieve the purpose of the present invention.

EXAMPLES The present invention will be explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[1] Measurement method First, the measurement method in the following examples and comparative examples will be explained.

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

(2) Measurement of composition ratio The sulfide-based inorganic solid electrolytes obtained in Examples and Comparative Examples were measured by ICP emission spectrometry using an ICP emission spectrometer (SPS3000, manufactured by Seiko Instruments). The mass % of Li, P, and S in the material was determined, and based on that, the molar ratio of each element was calculated.

(3) X-ray diffraction analysis Using an X-ray diffraction device (manufactured by Rigaku Corporation, RINT2000), the diffraction spectra of the sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples were determined by X-ray diffraction analysis method. I asked for it. Note that CuKα radiation was used as a radiation source. Here, the maximum diffraction intensity at the position of the diffraction angle 2θ = 35.0 ± 0.1° is defined as the background intensity _IA , and the maximum diffraction peak existing at the position of the diffraction angle 2θ = 17.2 ± 0.5° The diffraction intensity is I _B , the maximum diffraction intensity of the diffraction peak existing at the diffraction angle 2θ = 25.6 ± 0.5° is I _C , and the diffraction peak at the diffraction angle 2θ = 29.2 ± 0.8° is The maximum diffraction intensity of the existing diffraction peak was taken as _ID , and the maximum diffraction intensity of the diffraction peak existing at the position of the diffraction angle 2θ=26.6±0.4° was taken as _IE . In addition, I _B /I _A , I _C /I _A , I _D /I _A and I _E /I _A were determined, respectively.

(4) Measurement of lithium ion conductivity The lithium ion conductivity of the sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples was measured by an AC impedance method. In addition, the lithium ion conductivity of the sulfide-based inorganic solid electrolyte materials was measured even after exposing 1.0 g of the sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples to the atmosphere at 25°C for 10 minutes. We conducted each.
Lithium ion conductivity was measured using a potentiostat/galvanostat SP-300 manufactured by Biologic. The sample size was 9.5 mm in diameter and 1.2 to 2.0 mm in thickness, and the 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, the sample for measuring lithium ion conductivity is obtained by pressing 150 mg of the powdered sulfide-based inorganic solid electrolyte material obtained in the Examples and Comparative Examples at 270 MPa for 10 minutes using a press device. A plate-shaped sulfide-based inorganic solid electrolyte material with a diameter of 9.5 mm and a thickness of 1.2 to 2.0 mm was used.

(5) Measurement of maximum value of oxidative decomposition current Using a press device, 120 to 150 mg of the powdered sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples were pressed at 270 MPa for 10 minutes to obtain a diameter of 9. A plate-shaped sulfide-based inorganic solid electrolyte material (pellet) having a size of 5 mm and a thickness of 1.3 mm was obtained. Next, a Li foil was press-bonded to one side of the obtained pellet as a reference electrode and a counter electrode under conditions of 18 MPa for 10 minutes, and a SUS314 foil was closely attached to the other side as a working electrode.
Next, the sulfide-based inorganic solid electrolyte material was oxidized and decomposed using a potentiostat/galvanostat SP-300 manufactured by Biologic under conditions of a temperature of 25°C, a sweep voltage range of 0 to 5V, and a voltage sweep rate of 5mV/sec. The maximum value of the current was determined and evaluated based on the following criteria.
◎: 0.03 μA or less ○: Exceeding 0.03 μA 0.50 μA or less ×: Exceeding 0.50 μA

(6) Measurement of the amount of hydrogen sulfide generated In a glow box purged with argon gas, put the sulfide-based inorganic solid electrolyte materials (100 mg) obtained in Examples and Comparative Examples into a plastic container, and replace the plastic container with a glass The container was placed at the bottom of a sealed container (capacity: 1 L). Next, the glass sealed container was taken out into the air at room temperature, and ion-exchanged water (1 mL) was dripped onto the sulfide-based inorganic solid electrolyte material in the plastic container from the top of the glass sealed container. Next, 5 minutes after dropping the ion-exchanged water, a rubber gas absorption bag (manufactured by Okano Seisakusho Co., Ltd., product name: OG-3F-D) attached to the glass airtight container was deflated 10 times. After making the gas atmosphere inside the sealed container uniform, the concentration of hydrogen sulfide gas was measured at the measurement position shown in FIG. 4 using a detection tube (manufactured by Gastech, product name: No. 4LL).

[2] Production of solid electrolyte material <Example 1>
A sulfide-based inorganic solid electrolyte material was produced using the following procedure.
As raw materials, Li ₂ S (manufactured by Furukawa Kikai & Metals Co., Ltd., purity 99.9%), P ₂ S ₅ (manufactured by Kanto Kagaku Co., Ltd.) and Li ₃ N (manufactured by Furukawa Kikai & Metals Co., Ltd.) were used.
Next, in a glove box, using a crusher, Li ₂ S powder, P ₂ S ₅ powder, and Li ₃ N powder (Li ₂ S:P ₂ S ₅ :Li ₃ N=71.1:23.7:5 A raw material inorganic composition was prepared by mixing a total of 80 g of .3 (mol %)).
Next, 80 g of the raw material inorganic composition was subjected to mechanochemical treatment using a three-roll mill (BR-100V manufactured by Imex Corporation) to obtain a sulfide-based inorganic solid electrolyte material. Here, the first to third rolls were passed one time, and a total of 70 passes were made. Further, each roll was made of zirconia (ZrO ₂ ) and had a diameter of 63.5 mm, and the distance between the rolls was 20 μm. Further, the rotation speed of the first roll: the rotation speed of the second roll: the rotation speed of the third roll was set to be 1:2.5:6, and the rotation speed of the third roll was set to 700 rpm.
After passing through the first to third rolls 70 times, a portion of each sample was sampled and each physical property was evaluated. The results obtained are shown in Table 1.

<Example 2>
A sulfide-based inorganic solid electrolyte material was prepared in the same manner as in Example 1, except that the number of passes between the first roll and the third roll was changed to 40 times, and various evaluations were performed. The results obtained are shown in Table 1.

<Example 3>
A sulfide-based inorganic solid electrolyte material was prepared in the same manner as in Example 1, except that the number of passes between the first roll and the third roll was changed to 60 times, and various evaluations were performed. The results obtained are shown in Table 1.

<Example 4>
The mixing ratio of Li ₂ S powder, P ₂ S ₅ powder, and Li ₃ N powder was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 72.6:24.2:3.2 (mol%) A sulfide-based inorganic solid electrolyte material was produced in the same manner as in Example 1 except for the following, and various evaluations were performed. The results obtained are shown in Table 1.

<Example 5>
The mixing ratio of Li ₂ S powder, P ₂ S ₅ powder, and Li ₃ N powder was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 73.8:24.6:1.6 (mol%) A sulfide-based inorganic solid electrolyte material was produced in the same manner as in Example 1 except for the following, and various evaluations were performed. The results obtained are shown in Table 1.

<Comparative example 1>
A sulfide-based inorganic solid electrolyte material was produced in the same manner as in Example 1, except that the number of passes between the first roll and the third roll was changed to 10 times. Next, the obtained sulfide-based inorganic solid electrolyte material in a glass state was transferred to a carbon crucible and annealed at 270°C for 2 hours in an oven installed in a glove box to obtain a sulfide-based inorganic solid electrolyte material. . Each evaluation was performed. The results obtained are shown in Table 1.

<Comparative example 2>
A sulfide-based inorganic solid electrolyte material was produced using the following procedure.
As raw materials, Li ₂ S (manufactured by Furukawa Kikai & Metals Co., Ltd., purity 99.9%), P ₂ S ₅ (manufactured by Kanto Kagaku Co., Ltd.) and Li ₃ N (manufactured by Furukawa Kikai & Metals Co., Ltd.) were used.
Next, in a glove box, using a crusher, Li ₂ S powder, P ₂ S ₅ powder, and Li ₃ N powder (Li ₂ S:P ₂ S ₅ :Li ₃ N=71.1:23.7:5 A raw material inorganic composition was prepared by mixing a total of 80 g of .3 (mol %)).
Subsequently, 2 g of the raw inorganic composition and 500 g of ZrO ₂ balls with a diameter of 10 mm were placed inside an alumina pot (inner volume: 400 mL) in a glove box, and the pot was sealed.
Next, the alumina pot was taken out from inside the glove box, and the alumina pot was attached to a ball mill installed in a dry air atmosphere, and mechanochemical treatment was performed at 120 rpm for 300 hours to vitrify the raw inorganic composition. Ta. After every 24 hours of mixing, the powder adhering to the inner wall of the pot was scraped off in the glove box, and after the pot was sealed, milling was continued in a dry air atmosphere.
When the pot was opened after 36 hours of mechanochemical treatment, it was found that a lump of the inorganic composition had adhered to the inner wall of the pot. Therefore, it was necessary to scrape off the lumps of inorganic composition adhering to the inner wall of the pot every 24 hours.
Next, an alumina pot was placed in the glove box, and the obtained powder was separated from the ZrO ₂ balls, transferred from the alumina pot to a carbon crucible, and heated at 270°C for 2 hours in an oven placed in the glove box. An annealing treatment was performed to obtain a sulfide-based inorganic solid electrolyte material. Various evaluations were performed on the obtained sulfide-based inorganic solid electrolyte material. The results obtained are shown in Table 1.

The sulfide-based inorganic solid electrolyte material of the example exhibited less reduction in lithium ion conductivity than the sulfide-based inorganic solid electrolyte material of the comparative example even when exposed to the atmosphere. That is, it can be understood that the sulfide-based inorganic solid electrolyte materials of Examples can suppress a decrease in lithium ion conductivity when exposed to the atmosphere.
Here, the X-ray diffraction spectra of the sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples are shown in FIGS. 2 and 3, respectively.

100 Lithium ion battery 101 Positive electrode active material layer 103 Negative electrode active material layer 105 Current collector 110 Positive electrode 120 Electrolyte layer 130 Negative electrode

Claims (13)

A 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 amount of hydrogen sulfide generated of 20 ppm or less as measured by the method below.
(Method)
The sulfide-based inorganic solid electrolyte material is placed in a glass sealed container that has been replaced with argon gas, and then water is dripped onto the sulfide-based inorganic solid electrolyte material from the top of the glass sealed container for 5 minutes. Afterwards, the amount of hydrogen sulfide gas generated in the glass sealed container is measured. In 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 to 5.0, and the S content to the P content is A sulfide-based inorganic solid electrolyte material having a molar ratio S/P of 2.0 or more and 6.0 or less. The sulfide-based inorganic solid electrolyte material according to claim 1 or 2 ,
The lithium ion conductivity of the sulfide-based inorganic solid electrolyte material measured by the AC impedance method under the measurement conditions of 27.0° C., applied voltage 10 mV, and measurement frequency range 0.1 Hz to 7 MHz is 2.2×10 ⁻⁴ S cm ^{− 1} or more sulfide-based inorganic solid electrolyte material. The sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 3 ,
The sulfide-based inorganic solid electrolyte material has a maximum value of oxidative decomposition current of 0.50 μA or less, measured at a temperature of 25° C., a sweep voltage range of 0 to 5 V, and a voltage sweep rate of 5 mV/sec. Solid electrolyte material. The sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 4 ,
A sulfide-based inorganic solid electrolyte material in a glass-ceramic state. The sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 5 ,
The shape of the sulfide-based inorganic solid electrolyte material is particulate,
A sulfide-based inorganic solid electrolyte material, wherein the sulfide-based inorganic solid electrolyte material has an average particle diameter _d50 of 1 μm or more and 100 μm or less in a weight-based particle size distribution determined by a laser diffraction scattering particle size distribution measurement method. The sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 6 ,
A sulfide-based inorganic solid electrolyte material used in lithium-ion batteries. A solid electrolyte comprising the sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 7 . A solid electrolyte membrane comprising the solid electrolyte according to claim 8 as a main component. The solid electrolyte membrane according to claim 9 ,
A solid electrolyte membrane that is a press-molded body of the solid electrolyte in particulate form. The solid electrolyte membrane according to claim 9 or 10 ,
A solid electrolyte membrane in which the content of binder resin in the solid electrolyte membrane is less than 0.5% by mass when the entire solid electrolyte membrane is 100% by mass. The solid electrolyte membrane according to any one of claims 9 to 11 ,
A solid electrolyte membrane in which the content of the sulfide-based inorganic solid electrolyte material in the solid electrolyte membrane is 50% by mass or more when the entire solid electrolyte membrane is 100% by mass. A lithium ion battery comprising a positive electrode including a positive electrode active material layer, an electrolyte layer, and a negative electrode including a negative electrode active material layer,
A 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 according to any one of claims 1 to 7 .

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