JP6794518B2 - Manufacturing method of solid electrolyte material - Google Patents

Description

The present invention relates to a solid electrolyte material, a lithium ion battery and a method for producing a solid electrolyte material.

Lithium-ion batteries are generally used as a power source for small portable devices such as mobile phones and laptop 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.

Currently commercially available lithium ion batteries use an electrolytic solution containing a flammable organic solvent. On the other hand, a lithium-ion battery in which the electrolyte is changed to a solid electrolyte and the battery is completely solidified does not use a flammable organic solvent in the battery, so that the safety device can be simplified and the manufacturing cost and productivity are excellent. It is believed that. As the solid electrolyte material used for such a solid electrolyte, a sulfide-based material is known (for example, Patent Documents 1 and 2).

Since the sulfide-based solid electrolyte material has high lithium ion conductivity, it is useful for increasing the output of the battery, and various studies have been conducted conventionally. As the sulfide-based solid electrolyte, for example, Li ₂ SP ₂ S _5- based solid electrolyte materials have been proposed (for example, Patent Documents 1 and 2).

International Publication No. 2005/11706 Pamphlet Japanese Unexamined Patent Publication No. 2012-43654

However, although the above-mentioned sulfide-based solid electrolyte material is excellent in lithium ion conductivity, it is still lower than the electrolytic solution, and is not sufficiently satisfactory as a solid electrolyte material. Further, the all-solid-state lithium ion battery using such a solid electrolyte material is inferior in input / output characteristics.

The present invention has been made in view of the above circumstances, and provides a sulfide-based solid electrolyte material capable of realizing an all-solid-state lithium-ion battery having excellent lithium ion conductivity and excellent input / output characteristics. is there.

In order to provide a sulfide-based solid electrolyte material having excellent lithium ion conductivity, the present inventors have diligently studied the types of raw materials used for producing the solid electrolyte material, their blending ratios, production conditions, and the like. As a result, a sulfide-based material containing Li, P, and S as constituent elements and having a low diffraction intensity of a specific diffraction peak, or a sulfide-based material containing a specific amount of Li, P, and S is lithium ion. We have found that it has excellent conductivity, and have reached the present invention.

That is, according to the present invention.
As an element, Li, a manufacturing method for producing P, and including a solid electrolyte material S,
Including the step of vitrifying the mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N.
The solid electrolyte material has a diffraction peak at a position of at least a diffraction angle of 2θ = 17.7 ± 0.3 ° in a spectrum obtained by X-ray diffraction using CuKα ray as a radiation source, and the diffraction angle of 2θ =. the diffraction intensity of the diffraction peak at the position of 17.7 ± 0.3 ° and _{I a,} the diffraction intensity of the diffraction peak at the position of the diffraction angle 2θ = 26.9 ± 0.3 ° and _{I B} when _the value of I B / _{I a} is 0.50 or less, the manufacturing method of the solid electrolyte material is provided.

Further, according to the present invention,
As an element, Li, a manufacturing method for producing P, and including a solid electrolyte material S,
Including the step of vitrifying the mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N.
The solid electrolyte material has a molar ratio (Li / P) of the Li content to the P content in the solid electrolyte material of 3.15 or more and 3.45 or less, and the above P content to the P content. Provided is a method for producing a solid electrolyte material in which the molar ratio (S / P) of the S content is 3.79 or more and less than 4.00.

Further, according to the present invention
In the method for producing a solid electrolyte material,
When the _Li 2 S above Symbol mixture A, the sum of the _P 2 _{S 5} and the Li ₃ N was 100 mol%,
The content of the Li ₂ S is 70.0 mol% 63.0 mol% or more,
The content of P ₂ S ₅ is 23.0 mol% or more and 26.0 mol% or less.
Provided is a method for producing a solid electrolyte material, wherein the content of Li ₃ N is 6.5 mol% or more and 12.0 mol% or less.

According to the present invention, it is possible to provide a sulfide-based solid electrolyte material capable of realizing an all-solid-state lithium-ion battery having excellent lithium ion conductivity and excellent input / output characteristics.

It is sectional drawing which shows an example of the structure of the lithium ion battery of embodiment which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by a common reference numeral, and description thereof will be omitted as appropriate. Further, the figure is a schematic view and does not necessarily match the actual dimensional ratio. Unless otherwise specified, "~" represents the following from the above.

1. 1. First Embodiment Hereinafter, the first embodiment according to the present invention will be described.

[Solid electrolyte material]
First, the solid electrolyte material of the present embodiment will be described.
The solid electrolyte material of the present embodiment contains Li, P, and S as constituent elements.
The solid electrolyte material of the present embodiment has a diffraction peak at a position of at least a diffraction angle of 2θ = 17.7 ± 0.3 ° in a spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. Then, the diffraction intensity diffraction peaks at diffraction angles 2θ = 17.7 ± 0.3 ° and _{I A,} the diffraction intensity diffraction peaks at diffraction angles 2θ = 26.9 ± 0.3 ° _{I B} when the _value of I B / _{I a} is 0.50 or less, preferably 0.35 or less, more preferably 0.20 or less.
The I B _/ I _A With more than the above upper limit, it is possible to improve the lithium ion conductivity of the solid electrolyte material. Further, by using such a solid electrolyte material, an all-solid-state lithium ion battery having excellent input / output characteristics can be obtained.
Here, the diffraction peak existing at the position of the diffraction angle 2θ = 17.7 ± 0.3 ° is the reference diffraction peak, and the diffraction peak existing at the position of the diffraction angle 2θ = 26.9 ± 0.3 °. Is a diffraction peak derived from lithium sulfide (hereinafter, also referred to as Li ₂ S).
Therefore, I B _/ I _A represents an indication of the content of lithium sulfide solid electrolyte material of the present embodiment. As I B _/ I _A is small, means that the amount of lithium sulfide contained in the solid electrolyte material of the present embodiment is small.
Since Li ₂ S has low lithium ion conductivity, it is considered that the smaller the content of Li ₂ S, the better the lithium ion conductivity of the solid electrolyte.
Conventional solid electrolyte material is greater than I B _/ I _A is the upper limit value was greater the amount of lithium sulfide contained in the solid electrolyte material. Therefore, it is considered that the conventional solid electrolyte material could not sufficiently improve the lithium ion conductivity.
In contrast, the solid electrolyte material of the present embodiment, since I B _/ I _A is more than the above upper limit, it is possible to realize a good lithium ion conductivity. When the content of Li 2 _S is less than the prior art, it is considered because the amount of the component to inhibit lithium ion conductivity is small.
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.

Further, in the solid electrolyte material of the present embodiment, the molar ratio (Li / P) of the Li content to the P content in the solid electrolyte material is preferably 3.15 or more and 3.45 or less. It is more preferably 3.15 or more and 3.40 or less, further preferably 3.20 or more and 3.35 or less, and particularly preferably 3.20 or more and 3.33 or less. Further, the molar ratio (S / P) of the content of S to the content of P is preferably 3.79 or more and less than 4.00, and more preferably 3.80 or more and less than 4.00. More preferably, it is 3.81 or more and 3.98 or less, and particularly preferably 3.81 or more and 3.95 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.

By setting the molar ratio of Li / P and the molar ratio of S / P within the above ranges, even more excellent lithium ion conductivity can be obtained. The reason for this is not always clear, but the following reasons can be inferred.
In order to improve the lithium ion conductivity of the solid electrolyte material, it is important to change the structure so that the lithium ions easily hop while maintaining the stability of the compound. For example, increasing or decreasing the Li composition of the stable ortho-composition compound Li ₃ PS ₄ is an important factor. The common approach to increase or decrease the Li composition, method of changing the mixed amount of Li 2 _S which is one of the raw materials and the like. However, in this method, not only the Li composition but also the S composition changes, so that the bonding state of PS changes, and it is difficult to obtain the desired effect.
In this embodiment, as will be described later, a method using Li ₃ N is adopted as a method for increasing the Li composition of Li ₃ PS ₄ . Since N in Li ₃ N is discharged into the system as N ₂ , it is possible to increase only the Li composition with respect to Li ₃ PS ₄ by using Li ₃ N. According to the studies by the present inventors, it has been found that the lithium ion conductivity of the solid electrolyte can be improved by increasing the Li composition of Li ₃ PS ₄ by utilizing Li ₃ N.
On the other hand, increasing the mixing amount of Li ₃ N, Li ₃ N reacts with _P 2 _{S 5} Li ₃ N from the Li is Li ₂ S. Since Li ₂ S has low lithium ion conductivity, it becomes a factor of lowering the lithium ion conductivity of the solid electrolyte material.
Accordingly, the present inventors have conducted intensive studies in order to reduce the content of Li 2 _S solid electrolyte material to be obtained. As a result, by increasing the mixing ratio of P ₂ S ₅ , which is one of the raw materials, the content of Li ₂ S can be reduced, and as a result, the lithium ion conductivity of the obtained solid electrolyte is further improved. I found out what I could do. Therefore, in the present embodiment, as will be described later, the mixing ratio of P ₂ S ₅ is increased to suppress the content of Li ₂ S.
As described above, by utilizing Li ₃ N to increase the Li composition, increase the ratio of P ₂ S ₅ , and reduce the content of Li ₂ S, the molar ratio of Li / P and S / P The molar ratio of can be within the above range, which has never been seen before. When the molar ratio of the molar ratio and S / P of Li / P is within the above range, the stability and Li composition and Li 2 _S compounds amounts and are highly balanced, resulting in higher lithium ion conductivity It is considered that it led to the expression.

The solid electrolyte material of the present embodiment has at least a diffraction angle of 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 ° in a spectrum obtained by X-ray diffraction using CuKα ray as a radiation source. It is preferable to show a diffraction spectrum having a diffraction peak at the positions of 2θ = 29.6 ± 0.3 ° and 2θ = 38.8 ± 0.3 °.
Here, "diffraction angle 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 °, 2θ = 29.6 ± 0.3 °, and 2θ = 38.8 ± 0.3 °. "Having a diffraction peak at the position of" means that a new crystal structure different from the raw materials Li ₂ S, P ₂ S ₅ and Li ₃ N is generated. The details will be described later, but the mixture A containing the raw materials Li ₂ S, P ₂ S ₅ and Li ₃ N is vitrified, and the obtained mixture B in a glass state is pressure-molded and then heated. Diffraction peaks at 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 °, 2θ = 29.6 ± 0.3 °, and 2θ = 38.8 ± 0.3 ° Is to appear.
Therefore, it is presumed that these diffraction peaks are new diffraction peaks that appear because a new ordered structure is constructed from the glass state using Li ₂ S, P ₂ S ₅ and Li ₃ N as raw materials. The compound obtained by heat-treating and crystallizing the glassy mixture is generally called crystallized glass.
By having such a crystal structure, the solid electrolyte material of the present embodiment can further improve the lithium ion conductivity.

Examples of the shape of the solid electrolyte material of the present embodiment include particulate matter. Although particulate solid electrolyte material of the present embodiment is not particularly limited, the average particle size d ₅₀ in the weight particle size distribution by a laser diffraction scattering particle size distribution measurement method, is preferably 1μm or more 20μm or less, more preferably 1μm It is 10 μm or less.
By setting the average particle size d ₅₀ of the solid electrolyte material within the above range, good handleability can be maintained and lithium ion conductivity can be further improved.

[Manufacturing method of solid electrolyte material]
Subsequently, a method for producing the solid electrolyte material of the present embodiment will be described.
The solid electrolyte material of the present embodiment can be obtained, for example, by vitrifying a mixture A containing the raw materials Li ₂ S, P ₂ S ₅ and Li ₃ N in a specific ratio.
Further, it is preferable that the obtained mixture B in a glass state is pressure-molded and then heated (also referred to as heat treatment). More specifically, the solid electrolyte material of the present embodiment can be obtained by a production method including the following step (1). Moreover, it is preferable that the method for producing the solid electrolyte material of the present embodiment further includes the following step (2).

(1) Step of crystallization of mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N in a specific ratio (2) By heating the obtained mixture B in a glassy state after pressure molding. , Step of crystallizing at least a part of the mixture B Hereinafter, each step will be described.

<Step of vitrifying mixture A>
First, a mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N in a specific proportion is prepared. Here, the content of Li ₂ S in the mixture A is preferably 63.0 mol% or more and 70.0 mol% or less, more preferably 64.0 mol% or more and 69.0 mol% or less, and P ₂ S ₅ . preferably the content is 26.0 mol% or more 23.0 mol% or less, more preferably 25.0 mol% or more 23.5 mol% or less, Li ₃ N is preferably content of not less than 6.5 mol% 12 Li ₂ S, P ₂ S ₅ and Li ₃ N are mixed so as to be 0.0 mol% or less, more preferably 7.0 mol% or more and 11.5 mol% or less.
Here, the mixing amount of Li 3 _N With the above-mentioned range, while maintaining the stability of the resulting solid electrolyte material, it is possible to increase the Li composition.
Further, by setting the mixing amount of P ₂ S ₅ within the above range, the content of Li ₂ S can be reduced while maintaining the stability of the obtained solid electrolyte material.
It is difficult to remove only lithium sulfide from the obtained solid electrolyte material. Therefore, the value of I B _/ I _A to obtain a solid electrolyte material is within the scope of the present embodiment, as in the method for producing a solid electrolyte material of the present embodiment, a conventional mixing ratio of P ₂ S ₅ It is important to raise it above the standard of.
By thus highly controlled mixing ratio of the components is obtained as an element, Li, P, and comprises S, and, I B _/ I _A is a solid electrolyte material is within the scope of this embodiment be able to.

In addition, the mixed molar ratio is usually the reaction molar ratio as it is. Further, the mixed molar ratio of the present embodiment can be obtained by, for example, ICP emission spectroscopic analysis or X-ray photoelectron spectroscopy, but can usually be calculated from the weight ratio of the charged material.

Next, the mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N in the above proportions is vitrified.
Li _{2 S,} a mixture A containing P 2 _{S 5} and Li ₃ N as a method of _{vitrification} particularly limited as long as it is a method of Li 2 _S, a mixture A containing P 2 _{S 5} and Li ₃ N vitrifiable However, it can be carried out by, for example, mechanochemical treatment, melt quenching method, or the like.
Among these, it is preferable to carry out by mechanochemical treatment. This is because processing at room temperature is possible and the manufacturing process can be simplified. Further, the mechanochemical treatment may be a dry mechanochemical treatment or a wet mechanochemical treatment.
When the mechanochemical treatment is used, Li ₂ S, P ₂ S ₅ and Li ₃ N can be mixed while being pulverized into fine particles, so that the contact area of Li ₂ S, P ₂ S ₅ and Li ₃ N is increased. can do. As a result, the reaction of Li ₂ S, P ₂ S ₅ and Li ₃ N can be promoted, so that the solid electrolyte material of the present embodiment can be obtained even more efficiently.

Here, the mechanochemical treatment is a method of vitrifying a mixture object while applying mechanical energy such as shear force, collision force or centrifugal force. Examples of devices that perform vitrification by mechanochemical treatment include crushers / dispersers such as ball mills, bead mills, vibration mills, turbo mills, mechanofusions, and disc mills. Among these, a ball mill is preferable, and a planetary ball mill is particularly preferable. In a planetary ball mill, the base rotates while the pot rotates on its axis, so that extremely high impact energy can be efficiently generated. Therefore, a desired solid electrolyte material can be efficiently obtained.

Further, the mechanochemical treatment is preferably performed in a non-active atmosphere. As a result, the reaction between Li ₂ S, P ₂ S ₅ and Li ₃ N and water vapor, oxygen or the like can be suppressed.
The non-active atmosphere is a vacuum atmosphere of 1 to ^10-5 Pa or an inert gas atmosphere. Under the above-mentioned inactive 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 above-mentioned inert gas atmosphere is an atmosphere of an inert gas such as argon gas, helium gas, and nitrogen gas. 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 the inert gas into the mixed system is not particularly limited as long as the inside of the mixed system is filled with the inert gas atmosphere, but a method of purging the inert gas and continuing to introduce a certain amount of the inert gas. The method etc. can be mentioned.

Further, when vitrifying the mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N, an aprotic organic solvent such as hexane, toluene, or xylene was added to disperse each raw material in the solvent. It may be vitrified in the state. By doing so, vitrification can be performed more efficiently.

Mixing conditions such as rotation speed, processing time, temperature, reaction pressure, and gravitational acceleration applied to the mixture when vitrifying the mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N are the processing amount of the mixture A. Can be determined as appropriate. In general, the faster the rotation speed, the faster the glass formation rate, and the longer the processing time, the higher the conversion rate to glass. For example, when a general planetary ball mill machine is used, the rotation speed may be several tens to several hundreds rpm, and processing may be performed for 0.5 hours to 500 hours. Typically, when the X-ray diffraction analysis using CuKα rays as a radiation source, when the diffraction peak of P ₂ S ₅ and Li 3 _N is a raw material disappeared, the mixture A is vitrified, mixtures B It can be judged that it has been obtained.

The solid electrolyte material of the present embodiment is preferably more amorphous, from the viewpoint of further improving the conductivity of lithium ions.

(Li ₂ S)
The Li ₂ S of the present embodiment is not particularly limited, and a commercially available Li ₂ S may be used. For example, Li ₂ S obtained by the reaction of lithium hydroxide and hydrogen sulfide may be used. May be good. From the viewpoint of suppressing aspects and side reactions obtaining highly pure solid electrolyte material, it is preferred to use less Li 2 _S impurities.

The average particle size d ₅₀ in the weight particle size distribution by a laser diffraction scattering particle size distribution measurement method of Li 2 _S of this embodiment is preferably not average particle size d ₅₀ 30 [mu] m or less, more preferably 20μm or less, Particularly preferably, it is 10 μm or less. By setting the average particle diameter d ₅₀ to the above upper limit value or less, the contact area of Li ₂ S, P ₂ S ₅ and Li ₃ N can be increased. As a result, the reaction of Li ₂ S, P ₂ S ₅ and Li ₃ N can be promoted, so that the solid electrolyte material of the present embodiment can be obtained even more efficiently.
The lower limit of the average particle size d ₅₀ of Li 2 _S is not particularly limited, from the viewpoint of handling property, for example 1μm or more.

(P ₂ S ₅ )
The P ₂ S ₅ of the present embodiment is not particularly limited, and a commercially available P ₂ S ₅ can be used. From the viewpoint of suppressing aspects and side reactions obtaining highly pure solid electrolyte material, it is preferable to use a P ₂ S ₅ with less impurities. Further, instead of P ₂ S ₅ , elemental phosphorus (P) and elemental sulfur (S) having corresponding molar ratios can be used. Elemental phosphorus (P) and elemental sulfur (S) can be used without particular limitation as long as they are industrially produced and sold.

The average particle size d ₅₀ in the weight particle size distribution by a laser diffraction scattering particle size distribution measurement method of P ₂ S ₅ of the present embodiment is preferably not is 30μm or less average particle size d _50, more preferably be 20μm or less , Especially preferably 10 μm or less. By setting the average particle diameter d ₅₀ to the above upper limit value or less, the contact area of Li ₂ S, P ₂ S ₅ and Li ₃ N can be increased. As a result, the reaction of Li ₂ S, P ₂ S ₅ and Li ₃ N can be promoted, so that the solid electrolyte material of the present embodiment can be obtained even more efficiently.
The lower limit of the average particle size d ₅₀ of P ₂ S ₅ is not particularly limited, from the viewpoint of handling property, for example 1μm or more.

(Li ₃ N)
The Li ₃ N of the present embodiment is not particularly limited, and commercially available Li ₃ N may be used. For example, Li ₃ obtained by reacting metallic lithium (for example, Li foil) with nitrogen gas. N may be used. From the viewpoint of suppressing aspects and side reactions obtaining highly pure solid electrolyte material, it is preferred to use less Li 3 _N impurity.

The average particle size d ₅₀ in Li 3 _N by weight particle size distribution by a laser diffraction scattering particle size distribution measurement method of this embodiment is preferably not average particle size d ₅₀ 30 [mu] m or less, more preferably 20μm or less, Particularly preferably, it is 10 μm or less. By setting the average particle diameter d ₅₀ to the above upper limit value or less, the contact area of Li ₂ S, P ₂ S ₅ and Li ₃ N can be increased. As a result, the reaction of Li ₂ S, P ₂ S ₅ and Li ₃ N can be promoted, so that the solid electrolyte material of the present embodiment can be obtained even more efficiently.
The lower limit of the average particle size d ₅₀ of Li 3 _N is not particularly limited, from the viewpoint of handling property, for example 1μm or more.

<Step of crystallizing at least a part of mixture B>
Subsequently, a step of crystallizing at least a part of the mixture B by heating the obtained mixture B in a glass state after pressure molding will be described.
In the method for producing a solid electrolyte material of the present embodiment, the mixture B in a glass state containing Li ₂ S, P ₂ S ₅ and Li ₃ N in a specific ratio is pressure-molded and then heated to obtain the mixture B. It is preferable to crystallize at least a part. By doing so, a solid electrolyte material having further excellent lithium ion conductivity can be obtained.

The method of pressure molding the mixture B is not particularly limited, but for example, the obtained mixture B in a glass state is pressed at a pressure of 10 MPa or more and 300 MPa or less for about 1 to 60 minutes using a commercially available pressing device. A method of molding the mixture B into a plate shape can be mentioned.
The thickness of the press-molded plate-shaped mixture B is, for example, 0.1 mm or more and 3 mm or less.

The temperature at which the pressure-molded mixture B is heated is preferably in the range of 280 ° C. or higher and 500 ° C. or lower, and more preferably in the range of 280 ° C. or higher and 350 ° C. or lower.
When the temperature at which the mixture B is heated is within the above range, even more excellent lithium ion conductivity can be obtained.

The time for heating the mixture B is not particularly limited as long as the desired solid electrolyte material can be obtained, but is, for example, in the range of 1 minute or more and 24 hours or less, preferably 0.5 hour. It is more than 3 hours or less. The heating method is not particularly limited, and examples thereof include a method using a firing furnace. The conditions such as temperature and time for heating can be appropriately adjusted in order to optimize the characteristics of the solid electrolyte material of the present embodiment.

Further, it is preferable that the mixture B is heated, for example, in an inert gas atmosphere. Thereby, deterioration (for example, oxidation) of the solid electrolyte material can be prevented.
Examples of the inert gas when heating the mixture B include argon gas, helium gas, nitrogen gas and the like. It is preferable that these inert gases have a high purity in order to prevent impurities from being mixed into the product, and the dew point is preferably −50 ° C. or lower in order to avoid contact with moisture, preferably −60 ° C. It is particularly preferable that the temperature is below ° C. The method of introducing the inert gas into the mixed system is not particularly limited as long as the inside of the mixed system is filled with the inert gas atmosphere, but a method of purging the inert gas and continuing to introduce a certain amount of the inert gas. The method etc. can be mentioned.

By heating the mixture B after pressure molding in this way, the compositions of Li, P, and S tend to be uniform, and the fine particles are fused to each other at the glass softening point that passes before the glass powder crystallizes during heating. It is considered that the contact interface resistance between the fine particles is reduced and the lithium ion conductivity of the obtained solid electrolyte material can be further improved.

By such a production method, the solid electrolyte material of the present embodiment can be obtained.

<Process of crushing, classifying, or granulating>
In the method for producing a solid electrolyte material of the present embodiment, a step of pulverizing, classifying, or granulating the obtained solid electrolyte material may be further performed, if necessary. For example, a solid electrolyte material having a desired particle size can be obtained by making the particles finer by pulverization and then adjusting the particle size by a classification operation or a granulation operation. The crushing method is not particularly limited, and a known crushing method such as a mortar, a rotary mill, or a coffee mill can be used. Further, the classification method is not particularly limited, and a known method such as a sieve can be used.
These pulverizations or classifications are preferably carried out in an inert gas atmosphere or a vacuum atmosphere from the viewpoint of preventing contact with moisture in the air.
Further, the step of crushing, classifying, or granulating may be performed on the raw materials Li ₂ S, P ₂ S ₅ and Li ₃ N before the step (1) above, or the step (1) above. ) May be followed by the above mixture B.

In order to obtain the solid electrolyte material of the present embodiment, it is important to appropriately adjust each of the above steps. However, the method for producing the solid electrolyte material of the present embodiment is not limited to the above method, and the solid electrolyte material of the present embodiment can be obtained by appropriately adjusting various conditions.

The solid electrolyte material of the present embodiment does not decompose in the range of at least 5V to -5V, and exhibits high lithium ion conductivity of 1.6 × 10 ^-3 S · cm ^-1 or more at room temperature.
Here, the lithium ion conductivity is the lithium ion conductivity by the AC impedance method under the measurement conditions of 27.0 ° C., an applied voltage of 10 mV, and a measurement frequency range of 0.1 Hz to 7 MHz.
Therefore, the solid electrolyte material of the present embodiment is extremely useful as a solid electrolyte material for lithium ion batteries.
Further, the lithium ion battery using the solid electrolyte material of the present embodiment having the above characteristics is excellent in safety, input / output characteristics and charge / discharge cycle characteristics.

The solid electrolyte material of the present embodiment can be used in any application that requires lithium ion conductivity. Above all, the solid electrolyte material of the present embodiment is preferably used for a lithium ion battery. When the solid electrolyte material of the present embodiment is used for a lithium ion battery, it may be used for a positive electrode, a negative electrode, or an electrolyte layer.

[Solid electrolyte]
Next, the solid electrolyte of the present embodiment will be described. The solid electrolyte of the present embodiment contains the solid electrolyte material of the present embodiment as a main component.
The solid electrolyte of the present embodiment is not particularly limited, but as a component other than the solid electrolyte material of the present embodiment, for example, the solid electrolyte material of the present embodiment described above is used as long as the object of the present invention is not impaired. It may contain different types of solid electrolyte materials.

<A type of solid electrolyte material different from the solid electrolyte material of the present embodiment described above>
The solid electrolyte of the present embodiment may contain a different type of solid electrolyte material from the solid electrolyte material of the present embodiment. The type of solid electrolyte material different from the solid electrolyte material of the present embodiment is not particularly limited as long as it has ionic conductivity and insulating properties, but those generally used for lithium ion batteries can be used. .. For example, a sulfide solid electrolyte material, an oxide solid electrolyte material, and the like can be mentioned. Among these, a sulfide solid electrolyte material is preferable. As a result, an all-solid-state lithium-ion battery having excellent input / output characteristics can be obtained. Examples of the sulfide solid electrolyte material include Li ₂ S-P ₂ S ₅ material, Li ₂ S-SiS ₂ material, Li ₂ S-SiS ₂ -Li ₃ PO ₄ material, Li ₂ S-GeS ₂ material, and Li. _{2 S-P 2 S 5 -GeS} 2 _material, such as Li 2 _S-Al 2 S ₃ materials. Among these, the Li ₂ SP ₂ S ₅ material is preferable because it has excellent lithium ion conductivity.

[Lithium-ion battery]
FIG. 1 is a cross-sectional view showing an example of the structure of the lithium ion battery 100 according to the embodiment of the present invention.
The lithium ion battery 100 of 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. Then, 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 solid electrolyte material of 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 solid electrolyte material of the present embodiment. In the present embodiment, unless otherwise specified, the layer containing the positive electrode active material is referred to as the positive electrode active material layer 101, and the layer in which the positive electrode active material layer 101 is formed on the current collector 105 is referred to as the positive electrode 110. Further, the layer containing the negative electrode active material is called the negative electrode active material layer 103, and the layer in which the negative electrode active material layer 103 is formed on the current collector 105 is called the negative electrode 130.
The lithium ion battery 100 of the present embodiment is manufactured according to a generally known method. For example, the positive electrode 110, the solid electrolyte layer or the separator, and the negative electrode 130 of the present embodiment are stacked to form a cylindrical shape, a coin shape, a square shape, a film shape, or any other shape, and if necessary, non-water. It is produced by encapsulating an electrolytic solution.

<Positive electrode>
The positive electrode 110 is not particularly limited, and those generally used for lithium ion batteries can be used. The positive electrode 110 is not particularly limited, but 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 an aluminum foil.

The thickness and density of the positive electrode active material layer 101 are appropriately determined according to 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 of the present embodiment is not particularly limited, and generally known materials can be used. For example, composite oxides such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ); conductive polymers such as polyaniline and polypyrrole; Li ₂ S, Sulfides such as CuS, Li-Cu-S compounds, MoS ₂ and Li-Mo-S compounds can be used.

The positive electrode active material layer 101 is not particularly limited, but contains one or more materials selected from, for example, a binder, a thickener, a conductive auxiliary agent, a solid electrolyte material, and the like as components other than the positive electrode active material of the present embodiment. It may be. Hereinafter, each material will be described.

(binder)
The positive electrode active material layer 101 may contain a binder having a role of binding the positive electrode active materials to each other and the positive electrode active material to the current collector 105.
The binder of the present embodiment is not particularly limited as long as it is a normal binder that can be used in a lithium ion battery, and for example, polyvinyl alcohol, polyacrylic acid, carboxymethyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride, and styrene-butadiene rubber. , Polyimide and the like. These binders may be used alone or in combination of two or more.

(Thickener)
The positive electrode active material layer 101 may contain a thickener from the viewpoint of ensuring the fluidity of the slurry suitable for coating. The thickener of the present embodiment is not particularly limited as long as it is a normal thickener that can be used in a lithium ion battery, and for example, cellulosic polymers such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose, and ammonium salts thereof. Examples thereof include water-soluble polymers such as alkali metal salts, polycarboxylic acids, polyethylene oxides, polyvinylpyrrolidones, polyacrylates and polyvinyl alcohols. These thickeners may be used alone or in combination of two or more.

(Conductive aid)
The positive electrode active material layer 101 may contain a conductive auxiliary agent from the viewpoint of improving the conductivity of the positive electrode 110. The conductive auxiliary agent of the present embodiment is not particularly limited as long as it is a normal conductive auxiliary agent that can be used in a lithium ion battery, and for example, carbon black such as acetylene black and kechen black, and carbon such as vapor phase carbon fiber. Materials can be mentioned.

(Solid electrolyte material)
The positive electrode of the present embodiment may contain the solid electrolyte material of the present embodiment described above, or may contain a different type of solid electrolyte material from the solid electrolyte material of the present embodiment. The type of solid electrolyte material different from the solid electrolyte material of the present embodiment is not particularly limited as long as it has ionic conductivity and insulating properties, but a material generally used for an all-solid-state lithium ion battery is used. Can be done. For example, a sulfide solid electrolyte material, an oxide solid electrolyte material, and the like can be mentioned. Among these, a sulfide solid electrolyte material is preferable. As a result, an all-solid-state lithium-ion battery having excellent input / output characteristics can be obtained. Examples of the sulfide solid electrolyte material include Li ₂ S-P ₂ S ₅ material, Li ₂ S-P ₂ S _5- GeS ₂ material, Li ₂ S-SiS ₂ material, and Li ₂ S-SiS ₂ -Li ₃ Examples thereof include PO ₄ material, Li ₂ S-GeS ₂ material, and Li ₂ S-Al ₂ S ₃ material. Among these, the Li ₂ SP ₂ S ₅ material is preferable because it has excellent lithium ion conductivity.

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

<Negative electrode>
The negative electrode 130 is not particularly limited, and those generally used for lithium ion batteries can be used. The negative electrode 130 is not particularly limited, but 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 such as copper.

The thickness and density of the negative electrode active material layer 103 are appropriately determined according to the intended use of the battery and are not particularly limited, and can be set according to generally known information.

The negative electrode active material of the present embodiment is not particularly limited as long as it is a normal negative electrode active material that can be used for the negative electrode of a lithium ion battery, and for example, natural graphite, artificial graphite, resin charcoal, carbon fiber, activated charcoal, and hard carbon. , Carbon materials such as soft carbon; Lithium-based metals such as lithium metal and lithium alloy; Metals such as silicon and tin; Conductive polymers such as polyacene, polyacetylene and polypyrrole.

The negative electrode 130 is not particularly limited, but may include one or more materials selected from, for example, a binder, a thickener, a conductive auxiliary agent, a solid electrolyte material, and the like as components other than the negative electrode active material of the present embodiment. These materials are not particularly limited, and examples thereof include the same materials as those used for the positive electrode 110 described above.

<Electrolyte layer>
Next, the electrolyte layer 120 will be described. The electrolyte layer 120 is a layer formed between the positive electrode active material layer 101 and the negative electrode active material layer 103.
Examples of the electrolyte layer 120 include a separator impregnated with a non-aqueous electrolyte solution and a solid electrolyte layer containing a solid electrolyte.

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

A microporous polymer film is preferably used as the porous film, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, and polyester. In particular, a porous polyolefin film is preferable, and specific examples thereof include a porous polyethylene film and a porous polypropylene film.

(Non-aqueous electrolyte)
The non-aqueous electrolyte solution of the present embodiment is a solution in which an electrolyte is dissolved in a solvent.
Any known lithium salt can be used as the electrolyte, and it may be selected according to the type of active material. For _{example, LiClO 4, LiBF 6, LiPF} 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, CF 3 Examples thereof 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 lower fatty acid lithium carboxylate.

The solvent for dissolving the electrolyte is not particularly limited as long as it is usually used as a liquid for dissolving the electrolyte, and ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC). , Diethyl carbonate (DEC), methyl ethyl carbonate (MEC), vinylene carbonate (VC) and other carbonates; γ-butyrolactone, γ-valerolactone and other lactones; trimethoxymethane, 1,2-dimethoxyethane, diethyl ether , 2-ethoxyethane, tetrahydrofuran, 2-methyl tetrahydrofuran and other ethers; dimethylsulfoxide and other sulfoxides; 1,3-dioxolane, 4-methyl-1,3-dioxolane and other oxolanes; acetonitrile, nitromethane, formamide, Nitrogen-containing substances such as dimethylformamide; organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate; phosphate triesters and jiglimes; triglimes; sulfolanes, methylsulfolanes, etc. Sulfolans; oxazolidinones such as 3-methyl-2-oxazolidinone; sulfons such as 1,3-propanesulton, 1,4-butanesulton, naphthalusulton; and the like. These may be used individually by 1 type, or may be used in combination of 2 or more type.

(Solid electrolyte layer)
The solid electrolyte layer of the present 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 material contained in the solid electrolyte layer is not particularly limited as long as it has lithium ion conductivity, but in the present embodiment, the solid electrolyte material of the present embodiment is preferable.
The content of the solid electrolyte material in the solid electrolyte layer of the present embodiment is not particularly limited as long as the desired insulating property can be obtained, but is, for example, in the range of 10% by volume or more and 100% by volume or less. Above all, it is preferably in the range of 50% by volume or more and 100% by volume or less. In particular, in the present embodiment, it is preferable that the solid electrolyte layer is composed of only the solid electrolyte material of the present embodiment.

Moreover, the solid electrolyte layer of this embodiment may contain a binder. By containing the binder, a flexible solid electrolyte layer can be obtained. Examples of the binder 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 more preferably in the range of 0.1 μm or more and 300 μm or less.

2. 2. Second Embodiment Hereinafter, the second embodiment according to the present invention will be described.

[Solid electrolyte material]
First, the solid electrolyte material of the present embodiment will be described.
The solid electrolyte material of the present embodiment contains Li, P, and S as constituent elements.
Further, in the solid electrolyte material of the present embodiment, the molar ratio (Li / P) of the Li content to the P content in the solid electrolyte material is 3.15 or more and 3.45 or less, preferably. It is 3.15 or more and 3.40 or less, more preferably 3.20 or more and 3.35 or less, and particularly preferably 3.20 or more and 3.33 or less. Further, the molar ratio (S / P) of the content of S to the content of P is 3.79 or more and less than 4.00, preferably 3.80 or more and less than 4.00, more preferably. It is 3.81 or more and 3.98 or less, and particularly preferably 3.81 or more and 3.95 or less.

By setting the molar ratio of Li / P and the molar ratio of S / P within the above ranges, excellent lithium ion conductivity can be obtained. Since the reason for this is as described in the first embodiment, the description thereof will be omitted here.

The solid electrolyte material of the present embodiment has at least a diffraction angle of 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 ° in a spectrum obtained by X-ray diffraction using CuKα ray as a radiation source. It is preferable to show a diffraction spectrum having a diffraction peak at the positions of 2θ = 29.6 ± 0.3 ° and 2θ = 38.8 ± 0.3 °.
Here, "diffraction angle 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 °, 2θ = 29.6 ± 0.3 °, and 2θ = 38.8 ± 0.3 °. "Having a diffraction peak at the position of" means that a new crystal structure different from the raw materials Li ₂ S, P ₂ S ₅ and Li ₃ N is generated. As described in the first embodiment, the mixture A containing the raw materials Li ₂ S, P ₂ S ₅ and Li ₃ N is vitrified, and the obtained mixture B in a glass state is pressure-molded and then heated. Therefore, the positions of the diffraction angles 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 °, 2θ = 29.6 ± 0.3 °, and 2θ = 38.8 ± 0.3 °. This is because the diffraction peak appears in.
Therefore, it is presumed that these diffraction peaks are new diffraction peaks that appear because a new ordered structure is constructed from the glass state using Li ₂ S, P ₂ S ₅ and Li ₃ N as raw materials.
By having such a crystal structure, the solid electrolyte material of the present embodiment can further improve the lithium ion conductivity.

Examples of the shape of the solid electrolyte material of the present embodiment include particulate matter. The particulate solid electrolyte material of the present embodiment is not particularly limited, but the average particle diameter d ₅₀ in the weight-based particle size distribution measured by the laser diffraction / scattering particle size distribution measurement method is preferably 1 μm or more and 20 μm or less, more preferably 1 μm. It is 10 μm or less.
By setting the average particle size d ₅₀ of the solid electrolyte material within the above range, good handleability can be maintained and lithium ion conductivity can be further improved.

[Manufacturing method of solid electrolyte material]
Subsequently, a method for producing the solid electrolyte material of the present embodiment will be described.
The solid electrolyte material of the present embodiment can be produced according to the method for producing the solid electrolyte material according to the first embodiment. Details are omitted here.

[Solid electrolyte]
Hereinafter, the solid electrolyte of the present embodiment will be described. The solid electrolyte of the present embodiment is the same as the solid electrolyte of the first embodiment except that the solid electrolyte material of the present embodiment is contained as a main component instead of the solid electrolyte material of the first embodiment. Therefore, details are omitted here.

[Lithium-ion battery]
The lithium ion battery of the present embodiment is the same as the lithium ion battery 100 of the first embodiment except that the solid electrolyte material of the present embodiment is used instead of the solid electrolyte material of the first embodiment. Therefore, details are omitted here.

Although each embodiment of the present invention has been described above, these are examples of the present invention, and various configurations other than the above can be adopted.
The present invention is not limited to the above-described embodiment, and modifications and improvements within the range in which the object of the present invention can be achieved are included in the present invention.
Hereinafter, an example of the reference form will be added.
(Appendix 1)
Containing Li, P, and S as constituent elements,
In the spectrum obtained by X-ray diffraction using CuKα rays as the radiation source,
It has a diffraction peak at least at a position where the diffraction angle is 2θ = 17.7 ± 0.3 °.
The diffraction intensity of the diffraction peak at the position of the diffraction angle 2θ = 17.7 ± 0.3 ° and _{I A,} the diffraction of the diffraction peak at the position of the diffraction angle 2θ = 26.9 ± 0.3 ° when the strength was _{I B,}
The value of I _B / _{I A} is 0.50 or less, the solid electrolyte material.
(Appendix 2)
In the solid electrolyte material described in Appendix 1,
The molar ratio (Li / P) of the Li content to the P content in the solid electrolyte material is 3.15 or more and 3.45 or less, and the molar ratio of the S content to the P content is A solid electrolyte material having a ratio (S / P) of 3.79 or more and less than 4.00.
(Appendix 3)
In the solid electrolyte material according to Appendix 1 or 2,
In the spectrum obtained by X-ray diffraction using CuKα rays as the radiation source,
A solid electrolyte material having additional diffraction peaks at diffraction angles 2θ = 25.9 ± 0.3 °, 2θ = 29.6 ± 0.3 °, and 2θ = 38.8 ± 0.3 °.
(Appendix 4)
Containing Li, P, and S as constituent elements
The molar ratio (Li / P) of the Li content to the P content in the solid electrolyte material is 3.15 or more and 3.45 or less, and the molar ratio of the S content to the P content is A solid electrolyte material having a ratio (S / P) of 3.79 or more and less than 4.00.
(Appendix 5)
In the solid electrolyte material described in Appendix 4,
In the spectrum obtained by X-ray diffraction using CuKα rays as the radiation source,
At least at the position of diffraction angle 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 °, 2θ = 29.6 ± 0.3 °, and 2θ = 38.8 ± 0.3 °. A solid electrolyte material with diffraction peaks.
(Appendix 6)
A lithium ion battery including a positive electrode including a positive electrode active material layer, an electrolyte layer, and a negative electrode including a negative electrode active material layer.
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 solid electrolyte material according to any one of Appendix 1 to 5.
(Appendix 7)
Including the step of vitrifying the mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N.
When the total of the Li ₂ S, the P ₂ S ₅ and the Li ₃ N in the mixture A is 100 mol%,
The content of Li ₂ S is 70.0 mol% 63.0 mol% or more,
The content of P ₂ S ₅ is 23.0 mol% or more and 26.0 mol% or less.
A method for producing a solid electrolyte material, wherein the Li ₃ N content is 6.5 mol% or more and 12.0 mol% or less.
(Appendix 8)
In the method for producing a solid electrolyte material according to Appendix 7,
A step of pressure molding the mixture B obtained by the step of vitrifying the mixture A and
A step of crystallizing at least a part of the mixture B by heating the pressure-molded mixture B.
A method for producing a solid electrolyte material, further comprising.
(Appendix 9)
In the method for producing a solid electrolyte material according to Appendix 8,
In the step of crystallizing at least a part of the mixture B in a glassy state,
A method for producing a solid electrolyte material, in which the mixture B is heated at 280 ° C. or higher and 500 ° C. or lower in an inert gas atmosphere.
(Appendix 10)
In the method for producing a solid electrolyte material according to any one of Supplementary note 7 to 9,
In the step of vitrifying the mixture A,
A method for producing a solid electrolyte material, which vitrifies the mixture A by treating it with a mechanochemical treatment.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

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

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

(2) ICP Emission Spectroscopy Analysis Each of the solid electrolyte materials measured by ICP emission spectroscopy using an ICP emission spectroscopic analyzer (manufactured by Seiko Instruments Co., Ltd., SPS3000) and obtained in Examples and Comparative Examples. The mass% of each element was obtained, and based on this, the molar ratio of each element was calculated.

(3) X-ray Diffraction Analysis The diffraction spectra of the solid electrolyte materials obtained in Examples and Comparative Examples were obtained by the X-ray diffraction analysis method using an X-ray diffractometer (Rigaku Co., Ltd., RINT2000). In addition, CuKα ray was used as a radiation source.

(4) Measurement of Lithium Ion Conductivity The solid electrolyte materials obtained in Examples and Comparative Examples were measured for lithium ion conductivity by the AC impedance method.
The lithium ion conductivity was measured using a potentiostat / galvanostat SP-300 manufactured by Hokuto Denko. The size of the sample was φ9.5 mm, the thickness was about 1.3 mm, the measurement conditions were an applied voltage of 10 mV, a measurement temperature of 27.0 ° C., a measurement frequency range of 0.1 Hz to 7 MHz, and an electrode of Li foil.

(5) Charge / discharge test (charge / discharge cycle characteristics)
100 mg of Li ₆ MoS ₆ as a positive electrode active material, 100 mg of acetylene black as a conductive auxiliary agent, and 100 mg of solid electrolyte materials obtained in Examples and Comparative Examples described later, together with 500 g of zirconia balls having a diameter of 10 mm. It was placed in an alumina ball mill pot (internal volume 400 mL) and mixed at 120 rpm for 24 hours to prepare a positive electrode material.
400 mg of Li ₂₂ Si ₅ alloy, 200 mg of acetylene black, which is a conductive auxiliary agent, and 300 mg of the solid electrolyte material obtained in Examples and Comparative Examples described later, together with 500 g of φ10 mm zirconia balls, and an alumina ball mill pot. It was placed in (internal volume 400 mL) and mixed at 120 rpm for 24 hours to prepare a negative electrode material.
Subsequently, the positive electrode material (30 mg) obtained by the above method was pressed at 83 MPa using a press jig having φ = 14 mm. Solid electrolyte material 1 (150 mg) was laminated on this positive electrode and pressed at 83 MPa. Then, the negative electrode material (15 mg) obtained by the above method was laminated on the solid electrolyte layer side and press-molded at 270 MPa for 10 minutes to prepare an all-solid-state lithium ion battery. Next, the all solid state lithium ion battery obtained was charged to a charge termination voltage 3.5V at a current density of 65μA / cm ^2, at a current density of 65μA / cm ^2, until the discharge cutoff potential 0.9V Charging and discharging were performed 10 times under the condition of discharging. Here, when the first discharge capacity is 100%, the tenth discharge capacity is defined as the discharge capacity change rate [%]. Table 1 shows the evaluation results obtained for the discharge capacity and the discharge capacity change rate with respect to the total weight of the positive electrode material, the solid electrolyte material, and the negative electrode material.

(Input / output characteristics)
For all solid state lithium ion battery obtained by the method described above was charged to a charge termination voltage 3.5V at a current density of 325μA / cm ^2, at a current density of 325μA / cm ^2, discharge cutoff potential 0.9V It was charged and discharged once under the condition of discharging to. Here, Table 1 shows the evaluation results obtained for the discharge capacity with respect to the total weight of the positive electrode material, the solid electrolyte material, and the negative electrode material.

[2] Production of solid electrolyte material <Example 1>
As raw materials, Li ₂ S (manufactured by Alfa Aesar, purity 99.9%) and P ₂ S ₅ (reagent manufactured by Kanto Chemical Co., Inc.) were used. Li ₃ N was prepared by the following procedure.
First, a stainless steel net (150 mesh) was pressure-bonded to Li foil (purity 99.8%, thickness 0.5 mm) manufactured by Honjo Metal Co., Ltd. in a glove box having a nitrogen atmosphere. The Li foil began to change to black-purple from the opening of the net, and when left as it was at room temperature for 24 hours, all of the Li foil changed to black-purple Li ₃ N. Li ₃ N was pulverized in an agate mortar and then sieved with a stainless steel sieve, and a powder of 25 μm or less was recovered and used as a raw material for a 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 = 65.9: 24.4: 9.8 (mol%), and these powders were added. Mixed in an agate mortar for 20 minutes. Next, 2 g of the mixed powder was weighed, placed in 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 120 rpm for 200 hours. The powder after mixing and crushing was pressed at 270 MPa for 10 minutes using a pressing device to obtain a plate-shaped mixture having a thickness of 1.3 mm. The obtained mixture was placed in a carbon boat and heat-treated in an argon air stream at 330 ° C. for 2 hours to fuse the powders together to obtain a hard-sintered solid electrolyte material 1.

(Physical properties)
The solid electrolyte material 1 obtained in Example 1 was heat-treated to have a diffraction angle of 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 °, and 2θ = 29.6 ± 0. Diffraction peaks were shown at positions of 0.3 ° and 2θ = 38.8 ± 0.3 °. Then, the diffraction angle 2 [Theta] = 17.7 diffraction intensity diffraction peaks at diffraction angles 2θ = 26.9 ± 0.3 ° with respect to the diffraction intensity of the diffraction peak _{(I A)} present in ± 0.3 ° _{(I B} ratio) _(I B / I _a) was 0.16.
The Li / P molar ratio of the obtained solid electrolyte material 1 was 3.30, and the S / P molar ratio was 3.87.
The lithium ion conductivity was 1.8 × 10 ^-3 S · cm ^-1 .

<Example 2>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 65.4: 24.9: 9.7 (mol%). The solid electrolyte material 2 was obtained by wearing and sintering hard. The obtained evaluation results are shown in Table 1.

<Example 3>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 66.3: 23.8: 9.8 (mol%). The solid electrolyte material 3 was obtained by wearing and sintering hard. The obtained evaluation results are shown in Table 1.

<Example 4>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 68.4: 24.0: 7.6 (mol%). A solid electrolyte material 4 was obtained, which was applied and sintered hard. The obtained evaluation results are shown in Table 1.

<Example 5>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 64.2: 24.7: 11.1 (mol%). A solid electrolyte material 5 was obtained by wearing and sintering hard. The obtained evaluation results are shown in Table 1.

<Comparative example 1>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 71.1: 23.7: 5.3 (mol%). A solid electrolyte material 6 was obtained, which was applied and sintered hard. The obtained evaluation results are shown in Table 1.

<Comparative example 2>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 67.5: 22.5: 10.0 (mol%). A solid electrolyte material 7 was obtained by wearing and sintering hard. The obtained evaluation results are shown in Table 1.

<Comparative example 3>
The powders were fused in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 75.0: 25.0: 0 (mol%). , A hard-sintered solid electrolyte material 8 was obtained. The obtained evaluation results are shown in Table 1.

<Comparative example 4>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 68.4: 25.3: 6.3 (mol%). A solid electrolyte material 9 was obtained, which was applied and sintered hard. The obtained evaluation results are shown in Table 1.

<Comparative example 5>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 63.5: 23.5: 12.9 (mol%). A solid electrolyte material 10 was obtained, which was applied and sintered hard. The obtained evaluation results are shown in Table 1.

<Comparative Example 6>
The powders melted in the same manner as in Example 1 except that the ratio of each raw material was changed to Li ₂ S: P ₂ S ₅ : Li ₃ N = 63.0: 24.7: 12.3 (mol%). A solid electrolyte material 11 was obtained, which was applied and sintered hard. The obtained evaluation results are shown in Table 1.

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 (9)

As an element, Li, a manufacturing method for producing P, and including a solid electrolyte material S,
Including the step of vitrifying the mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N.
The solid electrolyte material has a diffraction peak at a position of at least a diffraction angle of 2θ = 17.7 ± 0.3 ° in a spectrum obtained by X-ray diffraction using CuKα ray as a radiation source, and the diffraction angle of 2θ =. the diffraction intensity of the diffraction peak at the position of 17.7 ± 0.3 ° and _{I a,} the diffraction intensity of the diffraction peak at the position of the diffraction angle 2θ = 26.9 ± 0.3 ° and _{I B} when _the value of I B / _{I a} is 0.50 or less, the manufacturing method of the solid electrolyte material. In the method for producing a solid electrolyte material according to claim 1,
The solid electrolyte material has a molar ratio (Li / P) of the Li content to the P content in the solid electrolyte material of 3.15 or more and 3.45 or less, and the P content to the P content. A method for producing a solid electrolyte material , wherein the molar ratio (S / P) of the S content is 3.79 or more and less than 4.00. In the method for producing a solid electrolyte material according to claim 1 or 2.
The solid electrolyte material has a diffraction angle of 2θ = 25.9 ± 0.3 °, 2θ = 29.6 ± 0.3 °, and 2θ = in the spectrum obtained by X-ray diffraction using CuKα ray as a radiation source. A method for producing a solid electrolyte material, which further has a diffraction peak at a position of 38.8 ± 0.3 °. As an element, Li, a manufacturing method for producing P, and including a solid electrolyte material S,
Including the step of vitrifying the mixture A containing Li ₂ S, P ₂ S ₅ and Li ₃ N.
The solid electrolyte material has a molar ratio (Li / P) of the Li content to the P content in the solid electrolyte material of 3.15 or more and 3.45 or less, and the P content to the P content. A method for producing a solid electrolyte material , wherein the molar ratio (S / P) of the S content is 3.79 or more and less than 4.00. In the method for producing a solid electrolyte material according to claim 4,
The solid electrolyte material has at least a diffraction angle of 2θ = 17.7 ± 0.3 °, 2θ = 25.9 ± 0.3 °, 2θ = in the spectrum obtained by X-ray diffraction using CuKα ray as a radiation source. A method for producing a solid electrolyte material having diffraction peaks at positions of 29.6 ± 0.3 ° and 2θ = 38.8 ± 0.3 °. In the method for producing a solid electrolyte material according to any one of claims 1 to 5,
When the total of the Li ₂ S, the P ₂ S ₅ and the Li ₃ N in the mixture A is 100 mol%,
The content of Li ₂ S is 70.0 mol% 63.0 mol% or more,
The content of P ₂ S ₅ is 23.0 mol% or more and 26.0 mol% or less.
A method for producing a solid electrolyte material, wherein the Li ₃ N content is 6.5 mol% or more and 12.0 mol% or less. In the method for producing a solid electrolyte material according to any one of claims 1 to 6 .
By pressurizing heat the mixture B obtained in the step of vitrifying the mixture A, at least a portion further comprises a more Engineering of crystallizing method of the solid electrolyte material of the mixture B. In the method for producing a solid electrolyte material according to claim 7 ,
In the step of crystallizing at least a part of the mixture B in a glassy state,
A method for producing a solid electrolyte material, in which the mixture B is heated at 280 ° C. or higher and 500 ° C. or lower in an inert gas atmosphere. In the method for producing a solid electrolyte material according to any one of claims 1 to 8 .
In the step of vitrifying the mixture A,
A method for producing a solid electrolyte material, which vitrifies the mixture A by treating it with a mechanochemical treatment.

Images