JP7239337B2 - solid electrolyte - Google Patents

Description

The present invention relates to solid electrolytes. The present invention also relates to an electrode mixture containing a solid electrolyte and an all-solid battery.

Since the all-solid-state battery does not use a flammable organic solvent, it is possible to simplify the safety device and achieve excellent manufacturing costs and productivity. It also has the feature of being able to achieve high voltage.

A sulfide solid electrolyte is being studied as one of the solid electrolytes used in all-solid-state batteries. Sulfide solid electrolytes are known to readily react with atmospheric moisture to generate hydrogen sulfide. For the purpose of suppressing the generation of hydrogen sulfide, for example, Patent Document 1 devises a manufacturing process for a sulfide solid electrolyte. Specifically, a raw material composition containing Li ₂ S, P ₂ S ₅ , LiI and LiBr is subjected to first mechanical milling using a ball mill to synthesize sulfide glass, and Bi ₂ is added to the sulfide glass. _S3 and an ether compound are added, and second mechanical milling using a ball mill is performed under the condition that the total pulverization energy E per unit mass is smaller than that of the first mechanical milling, and the sulfide glass is converted to _{Bi2S3 .} The sulfide glass modified with Bi ₂ S ₃ and atomized is sintered at a temperature equal to or higher than the crystallization temperature to obtain a sulfide solid electrolyte that is glass ceramics.

Patent Document 2 discloses a sulfide solid electrolyte compound for lithium ion batteries, which contains a cubic Argyrodite type crystal layer and is represented by the composition formula: Li _7-x+y P _S6-x Cl _x+y. It is x and y in the composition formula satisfy 0.05≤y≤0.9 and -3.0x+1.8≤y≤-3.0x+5.7.

JP 2018-133227 A International Publication No. 2016/104702 pamphlet

The method described in Patent Document 1 has a complicated manufacturing process, and is not suitable for industrially manufacturing a sulfide solid electrolyte in an economically viable manner. Accordingly, an object of the present invention is to improve a sulfide solid electrolyte, and more specifically to provide a sulfide solid electrolyte capable of suppressing generation of hydrogen sulfide.

As a result of intensive studies aimed at solving the above-mentioned problems, the inventors of the present invention have found that the generation of hydrogen sulfide can be effectively suppressed by appropriately adjusting the particle size distribution of the particles of the sulfide solid electrolyte. The present invention has been made based on this finding, and provides a solid electrolyte containing a lithium element, a phosphorus element and a sulfur element and having lithium ion conductivity,
When the volume cumulative particle size at 10% by volume, 50% by volume, and 90% by volume measured by a laser diffraction scattering particle size distribution measurement method is D ₁₀ , D ₅₀ and D ₉₀ respectively, (D ₉₀ −D ₁₀ )/ A solid electrolyte is provided having a _D50 value of less than 4.0.

The present invention also provides an electrode mixture containing the solid electrolyte and an active material.

Furthermore, the present invention provides an electrode layer containing the above solid electrolyte or the above electrode mixture.

Furthermore, the present invention provides an all-solid battery containing the solid electrolyte or the electrode mixture.

ADVANTAGE OF THE INVENTION According to this invention, the sulfide solid electrolyte which can suppress generation|occurrence|production of hydrogen sulfide is provided by a simple manufacturing method.

The present invention will be described below based on its preferred embodiments. The solid electrolyte of the present invention has lithium ion conductivity. Here, "having lithium ion conductivity" refers to having a predetermined lithium ion conductivity. The lithium ion conductivity of the solid electrolyte of the present invention is, for example, at room temperature, that is, at 25° C., preferably 1.0 mS/cm or more, preferably 4.0 mS/cm or more, especially 4.2 mS. /cm or more, particularly preferably 5.5 mS/cm or more, particularly preferably 6.0 mS/cm or more.

Lithium ion conductivity can be measured, for example, using the method described below. The solid electrolyte powder is uniaxially press-molded in a glove box filled with sufficiently dried Ar gas (dew point of −60° C. or less). Furthermore, it is molded at 200 MPa by a cold isostatic pressing device to produce pellets having a diameter of 10 mm and a thickness of about 4 mm to 5 mm. After coating the upper and lower surfaces of the pellet with a carbon paste as an electrode, heat treatment is performed at 180° C. for 30 minutes to prepare a sample for lithium ion conductivity measurement. The lithium ion conductivity of the obtained sample can be measured using, for example, Solartron 1255B manufactured by Toyo Technica Co., Ltd. Moreover, the measurement can be performed by the AC impedance method under conditions of a temperature of 25° C. and a frequency of 0.1 Hz to 1 MHz.

The solid electrolyte of the present invention is a so-called sulfide solid electrolyte containing lithium (Li) element, phosphorus (P) element and sulfur (S) element as constituent elements. The lithium ion conductivity of the solid electrolyte of the present invention is due to the sulfide solid electrolyte. In the present invention, it is advantageous to contain lithium element, phosphorus element, sulfur element and halogen element from the viewpoint of enhancing lithium ion conductivity. Examples of the halogen element include fluorine (F) element, chlorine (Cl) element, bromine (Br) element and iodine (I) element, and one or more elements selected from these may be used. can be done. In the present invention, it is advantageous to use elemental chlorine and/or elemental bromine as the halogen element from the standpoint of further improving the lithium ion conductivity. The sulfide solid electrolyte may contain elements other than lithium element, phosphorus element, sulfur element and halogen element. For example, part of the lithium element can be replaced with another alkali metal element, part of the phosphorus element can be replaced with another pnictogen element, and part of the sulfur element can be replaced with another chalcogen element.

The solid electrolyte of the present invention is usually composed of powder as an aggregate of particles. As a result of extensive studies by the present inventors, it was unexpectedly found that generation of hydrogen sulfide from the solid electrolyte can be effectively suppressed by adjusting the particle size distribution of the solid electrolyte powder. Specifically, the generation of hydrogen sulfide from the solid electrolyte can be effectively suppressed by making the particle size of the solid electrolyte particles as uniform as possible and sharpening the particle size distribution of the powder. The reason for this is not clear at present. As one reason, the present inventor considers as follows. If the solid electrolyte particles have non-uniform particle diameters and there are particles with various particle diameters, the probability of local compositional imbalance in the sulfur element constituting the solid electrolyte increases. Such particles are less stable to water and tend to generate hydrogen sulfide. It is believed that such particles act as starting points for the generation of hydrogen sulfide, increasing the amount of hydrogen sulfide generated. On the other hand, the more uniform the particle diameter of the solid electrolyte particles, the lower the probability that the sulfur element constituting the solid electrolyte will have a local compositional imbalance. In other words, the existence probability of particles with low stability to water becomes low. As a result, it is believed that generation of hydrogen sulfide is suppressed. However, the scope of the invention is not bound by this theory.

The sharpness of the particle size distribution can generally be evaluated using (D ₉₀ -D ₁₀ )/D ₅₀ as an index. D ₁₀ , D ₅₀ and D ₉₀ are volume cumulative particle diameters of particles at cumulative volumes of 10 volume %, 50 volume % and 90 volume %, respectively, measured by laser diffraction scattering particle size distribution measurement. In the present invention, by setting the value of (D ₉₀ −D ₁₀ )/D ₅₀ of the solid electrolyte powder to less than 4.0, the particle size distribution of the solid electrolyte powder becomes sharp, thereby generating hydrogen sulfide. is suppressed. From the viewpoint of making this effect more pronounced, the value of (D ₉₀ −D ₁₀ )/D ₅₀ may be, for example, less than 3.9, may be less than 3.8, or may be less than 3.7. may be less than On the other hand, the value of (D ₉₀ −D ₁₀ )/D ₅₀ may be greater than 0, 0.5 or greater, or 0.8 or greater. The present inventors have confirmed that when the value of (D ₉₀ −D ₁₀ )/D ₅₀ is within the above range, generation of hydrogen sulfide can be suppressed to a satisfactory level.

The particle size distribution of the solid electrolyte powder can be measured by laser diffraction scattering particle size distribution measurement, for example, by the following procedure. Using an automatic sample feeder for a laser diffraction particle size distribution analyzer (“Microtorac SDC” manufactured by Nikkiso Co., Ltd.), 6 ml of a sample (slurry) was added to a non-aqueous solvent (toluene), the flow rate was set to 50%, and 30 W of ultrasonic waves for 60 seconds. After that, for example, the particle size distribution is measured using a laser diffraction particle size distribution analyzer “MT3000II” manufactured by Nikkiso Co., Ltd., and the volume cumulative volume at 10% by volume, 50% by volume, and 90% by volume from the obtained volume-based particle size distribution chart. Particle size D ₁₀ , D ₅₀ and D ₉₀ values can be measured.
The water-insoluble solvent used in the measurement was passed through a 60 μm filter, the solvent refractive index was 1.50, the particle permeability condition was satisfied, the particle refractive index was 1.59, the shape was aspherical, and the measurement range was 0.5. 133 μm to 704.0 μm, the measurement time is 10 seconds, and the average values of two measurements are defined as D ₁₀ , D ₅₀ and D ₉₀ , respectively.
The sample (slurry) can be prepared by manually mixing 0.3 g of the solid electrolyte and 5.7 g of the dispersion liquid (mass ratio of toluene: SN Dispersant 9228 manufactured by San Nopco Co., Ltd. = 19:1).

The particle size distribution curve of the solid electrolyte powder measured by the laser diffraction scattering particle size distribution measurement method should have the above upper limit for the value of (D ₉₀ -D ₁₀ )/D ₅₀ . The particle size distribution curve may have, for example, only a single peak, or may have two or more peaks. Preferably.

In the present invention, in addition to sharpening the particle size distribution of the solid electrolyte powder, it is preferable to adjust the particle size of the solid electrolyte particles. Specifically, it is preferable to adjust the values of D ₁₀ , D ₅₀ and D ₉₀ in (D ₉₀ −D ₁₀ )/D ₅₀ described above. The values of D ₁₀ , D ₅₀ and D ₉₀ are each in the following ranges, provided that the value of (D ₉₀ −D ₁₀ )/D ₅₀ has a predetermined upper limit, so that generation of hydrogen sulfide is further enhanced. It is preferable from the viewpoint that it can be suppressed.
• D ₁₀ : preferably 0.1 μm or more and 1.9 μm or less. More preferably 0.3 μm or more and 1 μm or less. More preferably 0.35 μm or more and 0.6 μm or less.
• D ₅₀ : preferably 0.3 μm or more and 10 μm or less. More preferably 0.5 μm or more and 7 μm or less. More preferably 0.6 μm or more and 4 μm or less.
• D ₉₀ : preferably 0.5 μm or more and 50 μm or less. More preferably 0.7 μm or more and 10 μm or less. More preferably 1 μm or more and 5 μm or less.

It is also preferable that the solid electrolyte powder of the present invention does not contain coarse particles from the viewpoint of further suppressing the generation of hydrogen sulfide. From this point of view, the solid electrolyte powder of the present invention has a volume cumulative particle size D ₉₅ at a cumulative volume of 95% by volume measured by a laser diffraction scattering particle size distribution measurement method, provided that the value of D ₉₀ is not less than 65 μm. It is preferably less than 30 μm, more preferably 30 μm or less, and even more preferably 10 μm or less.

The crystallite size of the solid electrolyte of the present invention is within a specific range, which is advantageous from the viewpoint of suppressing generation of hydrogen sulfide. Hydrogen sulfide is likely to be generated from the solid electrolyte at grain boundaries, but by adjusting the crystallite size to a specific range, it is possible to reduce the grain boundaries as much as possible and generate hydrogen sulfide. This is because the number of sites with From this point of view, the crystallite size of the solid electrolyte of the present invention is, for example, preferably 10 nm or more, more preferably 20 nm or more, still more preferably 30 nm or more, and even more preferably 40 nm or more. preferable. On the other hand, the crystallite size of the solid electrolyte is, for example, preferably 160 nm or less, more preferably 120 nm or less, even more preferably 100 nm or less, and even more preferably 80 nm or less. When the crystallite size has the above lower limit, the particle interfaces can be appropriately reduced, so that high ionic conductivity can be obtained. In addition, since the crystallite size has the above upper limit, it is possible to obtain a lithium ion conduction path when used as an electrode mixture.

Crystallite size is measured by the following method. The measurement was performed using an XRD device "Smart Lab" manufactured by Rigaku Co., Ltd. under the conditions of scanning axis: 2θ/θ, scanning range: 10 to 140 deg, step width: 0.01 deg, and scanning speed: 1 deg/min. rice field. The crystallite size was calculated by analyzing the obtained analysis data with PDXL (a program manufactured by Rigaku Corporation) WPPF.

The specific surface area of the solid electrolyte powder of the present invention is also within a specific range, which is advantageous from the viewpoint of suppressing the generation of hydrogen sulfide. This is because, by adjusting the specific surface area of the solid electrolyte within a specific range, sites where hydrogen sulfide may be generated can be reduced as much as possible. From this viewpoint, the BET specific surface area of the solid electrolyte of the present invention is preferably 2 m ² /g or more and 30 m ² /g or less, more preferably 3 m ² /g or more and 20 m ² /g or less, and 4 m ² /g or more and 10 m ² /g or less is more preferable.

The BET specific surface area is calculated by the following method. Using a specific surface area measuring device "BELSORP-miniII" manufactured by MicrotracBEL, Inc., the adsorption/desorption isotherm was measured by the constant volume gas adsorption method, and the BET specific surface area was calculated by the multipoint method.

In order to adjust the (D ₉₀ −D ₁₀ )/D ₅₀ value, particle size, crystallite size and BET specific surface area of the solid electrolyte powder, the solid electrolyte powder may be subjected to appropriate pulverization treatment. For example, a solid electrolyte powder produced by a known method is roughly pulverized using a ball mill or the like, and then finely pulverized in a wet process to adjust the particle size distribution, particle size, crystallite size, and BET specific surface area. Specifically, pulverization conditions for wet fine pulverization, such as pulverization time, number of revolutions of the pulverizer, material of pulverization media, particle size of pulverization media, slurry concentration, slurry feeding amount, solid electrolyte powder Solid electrolyte powder having a desired particle size distribution can be obtained by controlling the mass ratio of the powder to the grinding media. Finding these pulverization conditions is within the technical common sense of a person skilled in the art and can be determined without imposing an undue burden on the person skilled in the art.

As described above, according to the present invention, a solid electrolyte powder in which generation of hydrogen sulfide is suppressed can be easily obtained by using a simple method of pulverization.

From the viewpoint of further increasing lithium ion conductivity, the solid electrolyte of the present invention preferably has an aldirodite crystal structure. The aldirodite-type crystal structure is a crystal structure possessed by a group of compounds derived from a mineral represented by the chemical formula: Ag ₈ GeS ₆ . It is particularly preferable that the sulfide solid electrolyte having an aldirodite-type crystal structure has a crystal structure belonging to a cubic system from the viewpoint of further improving lithium ion conductivity.

In the sulfide solid electrolyte having an aldirodite-type crystal structure, the halogen element contained therein is, for example, selected from the group consisting of fluorine (F) element, chlorine (Cl) element, bromine (Br) element and iodine (I) element. One or two or more elements can be used. From the viewpoint of improving lithium ion conductivity, it is particularly preferable to use elemental chlorine and/or elemental bromine as the halogen element.

A sulfide solid electrolyte having an aldirodite-type crystal structure has, for example, a composition formula: Li _7-a-2b PS _6-a-b X _a (X is fluorine (F) element, chlorine (Cl) element, bromine (Br ) element and iodine (I) element.) is particularly preferred from the viewpoint of further improving lithium ion conductivity. Examples of the halogen element in the composition formula include fluorine (F) element, chlorine (Cl) element, bromine (Br) element, and iodine (I) element. It may be a combination of two or more.

In the composition formula, a, which indicates the molar ratio of the X (halogen) element, is preferably 0.4 or more and 2.2 or less. When a is within this range, the cubic aldirodite crystal structure is stable near room temperature (25° C.), and the conductivity of lithium ions can be enhanced. From this point of view, a is more preferably 0.5 or more and 2.0 or less, particularly preferably 0.6 or more and 1.8 or less, and even more preferably 0.7 or more and 1.6 or less. .

In the composition formula, b is a value that indicates how small the Li ₂ S component is relative to the stoichiometric composition. From the viewpoint that the cubic aldirodite type crystal structure is stable near room temperature (25° C.) and the lithium ion conductivity is improved, it is preferable to satisfy −0.9≦b≦−a+2. In particular, from the viewpoint of enhancing the moisture resistance of the cubic aldirodite crystal structure, it is more preferable to satisfy −a+0.4≦b, and more preferably −a+0.9≦b.

Whether or not the sulfide solid electrolyte has an aldirodite-type crystal structure can be confirmed, for example, by XRD measurement. That is, in the XRD measurement measured by an X-ray diffractometer (XRD) using CuKα1 rays, the crystal phase of the aldirodite structure has 2θ = 15.34 ° ± 1.00 °, 17.74 ° ± 1.00 °, 25.19°±1.00°, 29.62°±1.00°, 30.97°±1.00°, 44.37°±1.00°, 47.22°±1.00 °, 51.70°±1.00°. Furthermore, for example, 2θ=54.26°±1.00°, 58.35°±1.00°, 60.72°±1.00°, 61.50°±1.00°, 70.46° There are also characteristic peaks at ±1.00° and 72.61°±1.00°. On the other hand, it can be confirmed that the sulfide solid electrolyte does not contain the crystal phase of the aldirodite structure by not having the characteristic peak of the crystal phase of the aldirodite structure described above.

The sulfide solid electrolyte having an aldirodite-type crystal structure means that the sulfide solid electrolyte has at least a crystal phase with an aldirodite-type structure. In the present invention, the sulfide solid electrolyte preferably has a crystal phase with an aldirodite structure as a main phase. The term "main phase" refers to the phase having the largest ratio with respect to the total amount of all crystal phases constituting the sulfide solid electrolyte. Therefore, the content of the crystalline phase having an aldirodite structure contained in the sulfide solid electrolyte is preferably, for example, 60% by mass or more, particularly 70% by mass or more, with respect to the total crystal phases constituting the sulfide solid electrolyte. , 80% by mass or more, more preferably 90% by mass or more. The proportion of the crystalline phase can be confirmed, for example, by XRD.

A sulfide solid electrolyte with an aldirodite-type crystal structure exhibits high lithium ion conductivity, but most of ^the S element is PS ₄ ^3- Compared with the crystalline Li ₃ PS ₄ and 75Li ₂ SP ₂ S ₅ glass constituting the unit, it is considered to have higher reactivity with water and generate more H ₂ S. On the other hand, the sulfide solid electrolyte of the present invention has (D ₉₀ −D ₁₀ )/D ₅₀ within a predetermined range, so that even if it has an aldirodite crystal structure, the amount of hydrogen sulfide generated can be effectively reduced. can be effectively suppressed.

The solid electrolyte of the present invention can be used, for example, as a material forming a solid electrolyte layer or as an electrode mixture forming an electrode layer containing an active material. Specifically, it can be used as a positive electrode mixture constituting a positive electrode layer containing a positive electrode active material, or a negative electrode mixture constituting a negative electrode layer containing a negative electrode active material. Therefore, the solid electrolyte of the present invention can be used in batteries having a solid electrolyte layer, so-called all-solid-state batteries. More specifically, it can be used for lithium all-solid-state batteries. The lithium all-solid-state battery may be a primary battery or a secondary battery, but is preferably used as a lithium secondary battery.

The all-solid-state battery has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer positioned between the positive electrode layer and the negative electrode layer, and has the solid electrolyte of the present invention. Examples of the shape of the battery include laminate type, cylindrical type and rectangular type.

The solid electrolyte layer of the present invention can be formed, for example, by dropping a slurry containing the solid electrolyte, a binder and a solvent onto a substrate and scraping it off with a doctor blade or the like, contacting the substrate with the slurry and then cutting it with an air knife, or screen printing. It can be produced by a method of forming a coating film by a method or the like, then drying by heating, and removing the solvent. Alternatively, the powder of the solid electrolyte of the present invention can be press-molded and then processed as appropriate. The solid electrolyte layer in the present invention may contain other solid electrolytes in addition to the solid electrolyte of the present invention. The thickness of the solid electrolyte layer in the present invention is typically preferably 5 μm or more and 300 μm or less, more preferably 10 μm or more and 100 μm or less.

As the positive electrode mixture in the all-solid-state battery containing the solid electrolyte of the present invention, for example, those used as positive electrode active materials in lithium secondary batteries can be used as appropriate. Examples of positive electrode active materials include spinel-type lithium transition metal compounds and lithium metal oxides having a layered structure. The particles of the positive electrode active material may have a coating layer on their surfaces that can reduce the reaction resistance between the solid electrolyte and the positive electrode active material. The positive electrode mixture may contain other materials such as a conductive aid in addition to the positive electrode active material.

As the negative electrode mixture in the all-solid-state battery containing the solid electrolyte of the present invention, for example, a negative electrode mixture used as a negative electrode active material for lithium secondary batteries can be appropriately used. Examples of negative electrode active materials include carbon materials such as lithium metal, artificial graphite, natural graphite and non-graphitizable carbon (hard carbon), silicon, silicon compounds, tin, and tin compounds. The negative electrode mixture may contain other materials such as a conductive aid in addition to the negative electrode active material.

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the scope of the invention is not limited to such examples. "%" means "% by mass" unless otherwise specified.

[Examples 1 and 2]
Li ₂ S powder, P ₂ S ₅ powder, LiCl powder, and LiBr powder were weighed so that the total amount was 75 g so as to have the composition shown in Table 1 below. These powders were pulverized and mixed using a ball mill to obtain a mixed powder. The mixed powder was fired to obtain a fired product having the composition shown in the same table. Firing was performed using a tubular electric furnace. During firing, 100% pure hydrogen sulfide gas was passed through the electric furnace at 1.0 L/min. The firing temperature was set to 500° C. and firing was performed for 4 hours. The fired product was coarsely pulverized using a mortar and pestle, and then finely pulverized to a predetermined particle size distribution. For fine pulverization, the pulverization time of the pulverizer, the rotation speed of the pulverizer, the material of the pulverization media, the particle size of the pulverization media, the concentration of the slurry, the amount of the slurry to be fed, the mass ratio of the fired material and the pulverization media, etc. conditions were set.

[Example 3]
Li ₂ S powder, P ₂ S ₅ powder, and LiCl powder were weighed so as to have a total amount of 75 g so as to have the composition shown in Table 1 below. Further, the pulverization conditions of the fired product were changed so that the particle size distribution was the value shown in Table 1. A solid electrolyte powder was obtained in the same manner as in Example 1 except for these.

[Example 4]
The fired product after fine pulverization in Example 1 was further finely pulverized with a wet planetary ball mill to obtain a sulfide solid electrolyte powder. The beads were made of _ZrO2 and their diameter was 5 mm. The mass ratio of slurry to beads was 0.17. The slurry concentration was 33%. Heptane was used as the slurry solvent.

[Comparative Examples 1 and 2]
In Example 1, a coarsely pulverized material pulverized to a predetermined particle size was used as the sulfide solid electrolyte powder.

〔evaluation〕
The sulfide solid electrolyte powders obtained in Examples and Comparative Examples were measured for particle size distribution, particle size, crystallite size (excluding Example 3), BET specific surface area, and lithium ion conductivity by the methods described above. Also, the amount of hydrogen sulfide generated was measured by the method described below. The results are shown in Table 1 below.

[Amount of hydrogen sulfide generated]
Under an argon atmosphere, 50 mg of the solid electrolyte powder was weighed and placed in a sealed container (volume: 1750 cm ³ , dew point: -30°C, dry air: temperature: 25°C). The amount of hydrogen sulfide generated was measured using a hydrogen sulfide sensor (GX-2009 manufactured by Riken Keiki Co., Ltd.) while circulating the air in the sealed container with an air pump. The volume of hydrogen sulfide generated within 1 hour after the solid electrolyte powder was exposed to dry air was measured. In Table 1, the amount of hydrogen sulfide generated is indicated by values per unit mass and per unit area of the solid electrolyte powder.

As is clear from the results shown in Table 1, the solid electrolyte powders having a sharp particle size distribution obtained in each example were found to suppress generation of hydrogen sulfide compared to the solid electrolyte powders of the comparative examples. .

Claims (9)

A solid electrolyte containing a lithium element, a phosphorus element and a sulfur element and having lithium ion conductivity,
When the volume cumulative particle size at 10% by volume, 50% by volume, and 90% by volume measured by a laser diffraction scattering particle size distribution measurement method is D ₁₀ , D ₅₀ and D ₉₀ respectively, (D ₉₀ −D ₁₀ )/ a _D50 value of less than 4.0;
The volume cumulative particle size D95 at a cumulative volume of 95% by volume measured by a laser diffraction scattering particle size distribution measurement method is less than 65 μm _,
A solid electrolyte having an aldirodite-type crystal structure. 2. The solid electrolyte according to claim 1, which has a volume cumulative particle size _D95 of 30 μm or less at a cumulative volume of 95% by volume measured by a laser diffraction scattering particle size distribution measurement method. 3. The solid electrolyte according to claim 1, containing chlorine and/or bromine. The solid electrolyte according to any one of claims 1 to 3, having a BET specific surface area of ^{2 m2} /g or more and 30 ^m2 /g or less. The solid electrolyte according to any one of claims 1 to 4, having a crystallite size of 10 nm or more and 160 nm or less. The solid electrolyte according to any one of claims 1 to 5, wherein _D50 is 0.3 µm or more and 10 µm or less. An electrode mixture comprising the solid electrolyte according to any one of claims 1 to 6 and an active material. An electrode layer comprising the solid electrolyte according to any one of claims 1 to 6 or the electrode mixture according to claim 7. An all-solid battery comprising the solid electrolyte according to any one of claims 1 to 6 or the electrode mixture according to claim 7.