KR102388035B1 - Sulfide-based solid electrolyte with increased doped amount of silicon element and preparing method thereof - Google Patents

Abstract

The present invention relates to a sulfide-based solid electrolyte having an increased silicon doping amount and containing no impurities and a method for preparing the same.

Description

SULFIDE-BASED SOLID ELECTROLYTE WITH INCREASED DOPED AMOUNT OF SILICON ELEMENT AND PREPARING METHOD THEREOF

The present invention relates to a sulfide-based solid electrolyte having an increased silicon doping amount and containing no impurities and a method for preparing the same.

Secondary battery technology used in electronic devices such as mobile phones and laptops and transportation means such as hybrid vehicles and electric vehicles requires electrochemical devices with higher stability and energy density.

Existing secondary battery technologies are currently mostly composed of cells based on organic solvents (organic liquid electrolytes), and thus have limitations in improving stability and energy density.

On the other hand, all-solid-state batteries using inorganic solid electrolytes are receiving a lot of attention recently because they are based on technology that excludes organic solvents and can produce cells in a safer and simpler form.

However, lithium-phosphorus-sulfur (Li-P-S)-based materials and lithium-antimony-sulfur (Li-Sb-S)-based materials, which are the most representative solid electrolytes for all-solid-state batteries developed so far, have low room temperature lithium ion conductivity, crystal There are problems such as phase instability, weak atmospheric stability, process limitations, and the composition ratio of the high-conductivity phase in a narrow area, so much research is still needed for mass production.

Recently, many attempts have been made to doping various elements in order to improve the physicochemical properties of the sulfide-based solid electrolyte.

J. Am. Chem. Soc. 2019, 141, 19002-19013 are Li _{6 . 7} Si _{0 . 7} Sb _{0 .} A sulfide-based solid electrolyte represented by ₃ S ₅ I was reported, Chem. Mater. 2019, 31, 4936-4944 prepared a sulfide-based solid electrolyte represented by Li _6.5 Si _0.5 P _0.5 S ₅ I, but there was a limit in increasing the doping amount of the silicon (Si) element. In addition, the conventional sulfide-based solid electrolyte has problems in that an impurity phase exists, lithium ion conductivity is low, and the manufacturing time is too long.

Korean Patent Registration No. 10-2063159 Korean Patent No. 10-1939568 Korean Patent Registration No. 10-1745209

J. Am. Chem. Soc. 2019, 141, 19002-19013 Chem. Mater. 2019, 31, 4936-4944

An object of the present invention is to provide a sulfide-based solid electrolyte having improved lithium ion conductivity by increasing the doping amount of silicon.

An object of the present invention is to reduce the price, weight, and toxicity of a solid electrolyte by increasing the doping amount of silicon instead of antimony (Sb).

Another object of the present invention is to provide a method for preparing a sulfide-based solid electrolyte in which impurities are not formed.

Another object of the present invention is to provide a sulfide-based solid electrolyte having high lithium ion conductivity at room temperature and low activation energy and excellent lithium ion conductivity even at low temperatures.

Another object of the present invention is to provide a method for producing a sulfide-based solid electrolyte advantageous for mass production due to a short synthesis time.

The object of the present invention is not limited to the object mentioned above. The object of the present invention will become clearer from the following description, and will be realized by means and combinations thereof described in the claims.

The sulfide-based solid electrolyte according to an embodiment of the present invention may be represented by the following Chemical Formula 1.

[Formula 1]

Li _{6 + a} M _{1 - a} Si _a S ₅ X

Here, 0 ≤ a ≤ 1, M includes any one or more selected from the group consisting of Sb, P, and As, and X includes any one or more halogen elements selected from the group consisting of Cl, Br and I.

In the sulfide-based solid electrolyte, a may satisfy 0.7 < a ≤ 1.

The sulfide-based solid electrolyte may have an azirodite-type crystal structure.

The sulfide-based solid electrolyte may not include an impurity phase.

The sulfide-based solid electrolyte may have a lithium ion conductivity of 13 mS/cm or more at 20°C to 30°C.

The sulfide-based solid electrolyte may have an activation energy of 0.18 eV or less.

The sulfide-based solid electrolyte may have a lithium ion conductivity of 6 mS/cm or more at 0°C to 10°C.

The method for preparing a sulfide-based solid electrolyte according to the present invention includes Li ₂ S, M _b S _c (M includes at least one selected from the group consisting of Sb, P and As, 0 ≤ b ≤ 5, 0 ≤ c ≤ 5 ), LiX (X is any one or more halogen elements selected from the group consisting of Cl, Br, and I), preparing a starting material containing Si, pulverizing the starting material, and heat-treating the pulverized product can do.

The manufacturing method may be that the starting material is pulverized with a ball-milling, followed by pulverizing at 400 rpm to 600 rpm for 10 to 30 minutes, and then repeating the steps of leaving for 30 to 50 minutes. there is.

The manufacturing method may be pulverizing the starting material by repeating it 50 to 100 times.

The manufacturing method may be to heat-treat the pulverized product in a powder state.

The manufacturing method may be to heat-treat the pulverized product in a vacuum state.

The manufacturing method may be to heat-treat the pulverized product at a temperature of 400° C. to 600° C. for 3 hours to 10 hours.

The manufacturing method may be to heat the pulverized product from room temperature to a temperature of 400 °C to 600 °C at a temperature increase rate of 1 °C/min to 5 °C/min for heat treatment.

According to the present invention, the silicon doping amount of the sulfide-based solid electrolyte can be increased, and thus lithium is additionally added, so that the lithium ion conductivity of the sulfide-based solid electrolyte can be improved.

In addition, according to the present invention, it is possible to obtain a sulfide-based solid electrolyte having a high silicon (Si) content, and accordingly, since the conventional antimony (Sb) content is reduced, it can have great advantages in terms of price and weight.

In addition, according to the present invention, it is possible to obtain a sulfide-based solid electrolyte in which impurities are not formed.

In addition, according to the present invention, a sulfide-based solid electrolyte having high lithium ion conductivity at room temperature and low activation energy and excellent lithium ion conductivity even at low temperatures can be obtained.

In addition, the method for producing a sulfide-based solid electrolyte according to the present invention can be of great help in mass production because the synthesis time is short.

The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 shows a method for preparing a sulfide-based solid electrolyte according to the present invention.
2a is an XRD analysis result of the sulfide-based solid electrolyte according to Examples 1, 2 and 3, and FIG. 2b is an enlarged XRD pattern near 2θ = 26°, 30°, and 42° in FIG. 2a, FIG. 2C is an enlarged XRD pattern in the vicinity of 2θ = 30° and 50° in FIG. 2A. In FIG. 2b , peaks of the impurity phase of LiI, Li ₂ S, Li ₃ SbS ₄ , and Li ₄ SiS ₄ do not appear.
It is the XRD analysis result of the sulfide-based solid electrolyte according to Example 2, and FIG. 2C is the XRD analysis result of the sulfide-based solid electrolyte according to Example 3.
3 is an XRD analysis result of a sulfide-based solid electrolyte according to Comparative Example 1. FIG.
4 is an XRD analysis result of a sulfide-based solid electrolyte according to Comparative Example 2.
5A is an electrochemical impedance spectroscopy (EIS) analysis result of the sulfide-based solid electrolyte according to Example 1, FIG. 5B is an EIS analysis result of the sulfide-based solid electrolyte according to Example 2, and FIG. 5C is a sulfide-based solid electrolyte according to Example 3 These are the results of EIS analysis of solid electrolytes.
6 is a result of measuring the activation energy of the sulfide-based solid electrolyte according to Examples 1 to 3.
7 is a result of measuring the activation energy of the sulfide-based solid electrolyte according to Comparative Example 1.
8 is a result of measuring the activation energy of the sulfide-based solid electrolyte according to Comparative Example 2.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed subject matter may be thorough and complete, and that the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In describing each figure, like reference numerals have been used for like elements. In the accompanying drawings, the dimensions of the structures are enlarged than the actual size for clarity of the present invention. Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present specification, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Also, when a part of a layer, film, region, plate, etc. is said to be “on” another part, it includes not only the case where the other part is “directly on” but also the case where there is another part in between. Conversely, when a part, such as a layer, film, region, plate, etc., is "under" another part, this includes not only cases where it is "directly under" another part, but also a case where another part is in the middle.

Unless otherwise specified, all numbers, values, and/or expressions expressing quantities of ingredients, reaction conditions, polymer compositions and formulations used herein, contain all numbers, values and/or expressions in which such numbers essentially occur in obtaining such values, among others. Since they are approximations reflecting various uncertainties in the measurement, it should be understood as being modified by the term "about" in all cases. Also, where the disclosure discloses numerical ranges, such ranges are continuous and inclusive of all values from the minimum to the maximum inclusive of the range, unless otherwise indicated. Furthermore, when such ranges refer to integers, all integers inclusive from the minimum to the maximum inclusive are included, unless otherwise indicated.

1 schematically shows a method for manufacturing a sulfide-based solid electrolyte according to the present invention. Referring to this, the method for preparing the sulfide-based solid electrolyte includes Li ₂ S, M _b S _c (M is any one or more selected from the group consisting of Sb, P and As, 0 ≤ b ≤ 5, 0 ≤ c ≤ 5), LiX (X is any one or more halogen elements selected from the group consisting of Cl, Br and I), preparing a starting material containing Si (S10), pulverizing the starting material (S20) and pulverizing and heat-treating the water (S30).

According to the manufacturing method of the sulfide-based solid electrolyte, a sulfide-based solid electrolyte without impurities can be obtained, and since the doping amount of silicon can be increased compared to the prior art, additional lithium is added to improve the lithium ion conductivity of the sulfide-based solid electrolyte can do it

The sulfide-based solid electrolyte may be a compound represented by the following formula (1).

[Formula 1]

Li _{6 + a} M _{1 - a} Si _a S ₅ X

Here, a may satisfy 0 ≤ a ≤ 1, or 0 < a ≤ 1, or 0.7 < a ≤ 1, or 0.75 ≤ a ≤ 1.

The M may include any one or more selected from the group consisting of Sb, P and As.

X may include a halogen element. The halogen element may be any one or more selected from the group consisting of Cl, Br, and I. When X includes two or more halogen elements, the sulfide-based solid electrolyte may be a compound represented by Formula 2 below.

[Formula 2]

Li _6+a M _1-a Si _a S ₅ X1 _b X2 _1-b

Here, a and M are the same as described above.

X1 and X2 may represent different halogen elements, and b may satisfy 0<b<1.

Hereinafter, each step of the method for producing a sulfide-based solid electrolyte according to the present invention will be described in detail.

The content of each component included in the starting material can be prepared by appropriately adjusting it according to the composition of the sulfide-based solid electrolyte to be finally obtained.

Thereafter, the starting material may be pulverized through high-energy milling (S20). Specifically, the starting material may be pulverized by a ball-milling method. More specifically, using a ball mill device, grinding at a high speed of 400 rpm to 600 rpm for 10 to 30 minutes and then leaving it for 30 to 50 minutes is referred to as one cycle, and this is repeated 50 to 100 times. to be crushed. If the grinding speed, grinding time, and leaving time of the ball mill device are less than the above numerical range, the reaction and vitrification of the starting material may not sufficiently occur, and if the above numerical range is exceeded, the starting material may be destroyed.

The total execution time of the pulverizing the starting material is not limited, but may be, for example, 50 hours to 70 hours.

Finally, the pulverized product that has been subjected to the above process may be heat-treated (S30).

The present invention is characterized in that the pulverized product is heat-treated in a powder state. As will be described later, in the conventional method of manufacturing a sulfide-based solid electrolyte, a raw material is heat-treated in a pellet state. The present invention is characterized in that the pulverized material is heat-treated in a powder state with a large surface area so that heat can be more evenly transmitted to the pulverized material, and impurities are effectively removed at the same time.

In addition, by heat-treating the pulverized product in a powder state, the heat treatment time can be significantly reduced, and the pulverized product may be heat-treated at a temperature of 400° C. to 600° C. for 3 hours to 10 hours. Here, for the heat treatment of the pulverized product, it may be heated at a temperature increase rate of 1 °C/min to 5 °C/min from room temperature to the desired temperature or temperature range of the heat treatment. In this specification, "room temperature" may mean 20 ± 5 ℃.

The total execution time of the step of heat-treating the pulverized material is not limited, but may be, for example, 7 hours to 15 hours.

In addition, the pulverized product may be heat-treated in a vacuum state in a closed system. However, the present invention is not limited thereto, and the heat treatment may be performed in an appropriate atmosphere depending on the device and environment used, such as an inert gas atmosphere. However, since the sulfide-based solid electrolyte may be unstable in the atmosphere, it may be desirable to avoid an air atmosphere.

Hereinafter, another embodiment of the present invention will be described in more detail through Examples. The following examples are only examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example 1

In order to prepare a sulfide-based solid electrolyte represented by Li ₆ SbS ₅ I (a=0), each starting material was weighed and prepared.

The starting material was pulverized with a ball mill. After milling for about 20 minutes at a speed of about 510 rpm, it was rested for about 40 minutes. This was made 1 cycle, and a total of 60 cycles were repeated.

The pulverized material was heated from room temperature to a temperature of about 450° C. at a temperature increase rate of about 2° C./min in a vacuum atmosphere, and then heat-treated for about 5 hours. The pulverized product was used in a powder state.

After the heat treatment was completed, a sulfide-based solid electrolyte represented by Li ₆ SbS ₅ I was obtained.

Example 2

Li _{6 . 5} Sb _{0 . 5} Si _{0 .} A sulfide-based solid electrolyte was prepared in the same manner as in Example 1, except that each starting material was weighed and prepared to prepare a sulfide-based solid electrolyte represented by ₅ S ₅ I (a=0.5).

Example 3

Li _{6 . 75} Sb _{0 . 25} Si _{0 .} A sulfide-based solid electrolyte was prepared in the same manner as in Example 1, except that each starting material was weighed and prepared to prepare a sulfide-based solid electrolyte represented by ₇₅ S ₅ I (a=0.75).

Comparative Example 1

J. Am. Chem. Soc. The sulfide-based solid electrolyte disclosed in 2019, 141, 19002-19013 was set as Comparative Example 1. The sulfide-based solid electrolyte according to Comparative Example 1 is a compound represented by the following formula (2).

[Formula 2]

Li _6+x Sb _1-x Si _x S ₅ I

X=0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7

In Comparative Example 1, a sulfide-based solid electrolyte was prepared as follows.

The starting materials are mixed with an agate mortar to obtain a mixture.

The mixture is heat-treated in a vacuum state in a pellet state. Specifically, the primary heat treatment is performed at 500° C. for 7 days, and the pellets are pulverized and then re-formed into pellets and subjected to secondary heat treatment at 500° C. for 7 days.

Comparative Example 2

Chem. Mater. The sulfide-based solid electrolyte disclosed in 2019, 31, 4936-4944 was set as Comparative Example 2. The sulfide-based solid electrolyte according to Comparative Example 2 is a compound represented by the following formula (3).

[Formula 3]

Li _6+x P _1-x Si _x S ₅ I

X=0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8

In Comparative Example 2, a sulfide-based solid electrolyte was prepared as follows.

The starting materials are mixed with an agate mortar to obtain a mixture.

The mixture is heat-treated in a vacuum state in a pellet state. Specifically, heat treatment is performed while maintaining the temperature at 550 °C for 14 days.

Experimental Example 1 - XRD (X-ray diffraction) analysis

XRD analysis of the sulfide-based solid electrolytes according to Examples 1 to 3, Comparative Examples 1 and 2 was performed. The results of the sulfide-based solid electrolytes according to Examples 1 to 3 are shown in FIG. 2A. FIG. 2B is an enlarged XRD pattern near 2θ = 26°, 30°, and 42° in FIG. 2A , and FIG. 2C is an enlarged XRD pattern near 2θ = 30° and 50° in FIG. 2A . The result of the sulfide-based solid electrolyte according to Comparative Example 1 is shown in FIG. 3 . The result of the sulfide-based solid electrolyte according to Comparative Example 2 is shown in FIG. 4 .

Referring to FIG. 3 , it can be seen that in Comparative Example 1, peaks corresponding to impurities such as LiI and Li ₂ S were found. Also, referring to FIG. 4 , it can be seen that in Comparative Example 2, a peak corresponding to an impurity was found near 2θ = 30° in the results of x=0.7 and 0.8 with high silicon doping amount.

Meanwhile, referring to FIGS. 2A to 2C , in Examples 1 to 3, peaks corresponding to impurities such as LiI, Li ₂ S, Li ₃ SbS ₄ , Li ₄ SiS ₄ were not found at all, and 2θ = 30° It can be seen that the peak does not split and appears clearly even in the vicinity. As a result, it can be confirmed that the sulfide-based solid electrolyte according to the present invention does not contain impurities.

In addition, Examples 1 to 3 are 2θ = 17˚±1.00˚, 24˚±1.00˚, 28˚±1.00˚, 30˚±1.00˚, 38±1.00˚, 42˚±1.00˚, 49˚± As peaks appear in the ranges of 1.00˚, 53±1.00˚, 56±1.00˚ and 59±1.00˚, it can be seen that the sulfide-based solid electrolyte according to the present invention has an azirodite-type crystal structure.

Experimental Example 2 - Electrochemical impedance spectroscopy (EIS) analysis

In order to measure the lithium ion conductivity of the sulfide-based solid electrolytes according to Examples 1 to 3, AC impedance analysis was performed at room temperature. Each powder was charged into a conductivity measuring mold, and a sample having a diameter of 6 mm and a thickness of 0.5-5 mm was prepared through 1.2-ton uniaxial cold press molding. An AC potential of 100 mV was applied to the sample, and a frequency sweep was performed from 1 Hz to 1 MHz to obtain the impedance of the sample. The results of Examples 1 to 3 are shown in FIGS. 5A to 5C, respectively.

Referring to this, the lithium ion conductivity of Examples 1 to 3 was measured to be 7.81×10 ⁻³ mS/cm, 11.6 mS/cm, and 13.1 mS/cm, respectively.

The lithium ion conductivity at room temperature of the sulfide-based solid electrolytes according to Comparative Examples 1 and 2 is shown in Table 1 below.

Manufacturing method Furtherance Li-ion conductivity (room temperature) Example 1 Li ₆ SbS ₅ I 7.81×10 ^-3 mS/cm Example 2 Li _{6 . 5} Sb _{0 . 5} Si _{0 . 5} S ₅ I 11.6 mS/cm Example 3 Li _6.75 Sb _0.25 Si _0.75 S ₅ I 13.1 mS/cm Comparative Example 1 Li _{6 . 5} Sb _{0 . 5} Si _{0 . 5} S ₅ I 9.98 mS/cm Comparative Example 1 Li _{6 . 7} Sb _{0 . 3} Si _{0 . 7} S ₅ I 12.6 mS/cm Comparative Example 2 Li _{6.7 P 0.3 Si 0 . 7} S ₅ I 2.0 mS/cm

Referring to this, it can be seen that the lithium ion conductivity of Example 3 according to the present invention is the highest among Examples 3, Comparative Example 1, and Comparative Example 2 in which the doping amount of silicon is similar.

Experimental Example 3 - Measurement of activation energy (E _a )

로, 전도도

는 온도에 따른 exponential 관계식으로 표현되며 (

는 fitting되는 상수 값,

는 볼츠만 상수) 이를 통해,

을 구할 수 있다. 그 결과는 도 6과 같다.The activation energy of the sulfide-based solid electrolytes according to Examples 1 to 3 was measured. The activation energy was measured using the Arrhenius relational expression by measuring the ion conductivity according to the temperature. The Arrhenius relation is

furnace, conductivity

is expressed as an exponential relation according to temperature (

is the constant value to be fitted,

is the Boltzmann constant) through which,

can be obtained The result is shown in FIG. 6 .

The activation energy of the sulfide-based solid electrolyte according to Comparative Example 1 and Comparative Example 2 is shown in FIGS. 7 and 8, respectively.

Referring to this, it can be seen that Examples 1 to 3 have activation energies of 0.18 eV, 0.16 eV, and 0.17 eV, respectively, whereas Comparative Examples 2 and 3 show that all samples have a result value of 0.2 eV or more.

을 이용하여 저온에서의 값을 예측하면, 0 ℃ ~ 10 ℃에서의 리튬이온 전도도가 6 mS/cm 이상인 것을 특징으로 한다.As a result, according to the present invention, a sulfide-based solid electrolyte having a low activation energy can be obtained, and it can be said that lithium ion conductivity at low temperature is improved. The sulfide-based solid electrolyte according to the present invention has an activation energy of 0.18 eV or less.

When the value at low temperature is predicted using

The sulfide-based solid electrolyte prepared by the conventional method contains impurities, takes a long synthesis time, and has a limit in the doping amount of silicon.

On the other hand, when the sulfide-based solid electrolyte is prepared by the method according to the present invention, the doping amount of silicon can be increased compared to the prior art. Accordingly, the lithium ion conductivity is improved, and since the amount of silicon substitution for antimony (Sb) is high, the price, weight and toxicity are reduced.

In addition, according to the present invention, it is possible to obtain a sulfide-based solid electrolyte from which all impurities are removed.

In addition, since the sulfide-based solid electrolyte according to the present invention has low activation energy, it exhibits high lithium ion conductivity even at low temperatures. The lithium ion conductivity (10 mS/cm or more) and low activation energy (0.2 eV or less) at room temperature of the sulfide-based solid electrolyte according to the present invention is reported for the first time.

In addition, according to the present invention, since the above-described sulfide-based solid electrolyte can be synthesized in a short time, it is very advantageous for mass production.

As the experimental examples and examples of the present invention have been described in detail above, the scope of the present invention is not limited to the above-described experimental examples and examples, and the basic concept of the present invention defined in the following claims. Various modifications and improved forms used by those skilled in the art are also included in the scope of the present invention.

Claims (20)

A sulfide-based solid electrolyte that is represented by the following formula (1) and does not include an impurity phase.
[Formula 1]
Li _6+a M _1-a Si _a S ₅ X
Here, 0 < a < 1, M is Sb, X includes any one or more halogen elements selected from the group consisting of Cl, Br, and I. According to claim 1,
Wherein a is a sulfide-based solid electrolyte that satisfies 0.7 < a < 1. According to claim 1,
A sulfide-based solid electrolyte comprising an azirodite-type crystal structure. delete According to claim 1,
A sulfide-based solid electrolyte having a lithium ion conductivity of 13 mS/cm or more at 20°C to 30°C. According to claim 1,
A sulfide-based solid electrolyte, characterized in that the activation energy is 0.18 eV or less. According to claim 1,
A sulfide-based solid electrolyte having a lithium ion conductivity of 6 mS/cm or more at 0°C to 10°C. Li ₂ S, M _b S _c (M is Sb, 0 < b ≤ 5, 0 < c ≤ 5), LiX (X is any one or more halogen elements selected from the group consisting of Cl, Br and I) and Si Preparing a starting material comprising;
grinding the starting material; and
heat-treating the pulverized product;
A method for producing a sulfide-based solid electrolyte represented by the following formula (1) and does not include an impurity phase.
[Formula 1]
Li _6+a M _1-a Si _a S ₅ X
Here, 0 < a < 1, M is Sb, X includes any one or more halogen elements selected from the group consisting of Cl, Br, and I. 9. The method of claim 8,
wherein a satisfies 0.7 < a < 1. A method for producing a sulfide-based solid electrolyte. 9. The method of claim 8,
A method for producing a sulfide-based solid electrolyte comprising an azirodite-type crystal structure. delete 9. The method of claim 8,
A method for producing a sulfide-based solid electrolyte, characterized in that the lithium ion conductivity at 20°C to 30°C is 13 mS/cm or more. 9. The method of claim 8,
A method for producing a sulfide-based solid electrolyte, characterized in that the activation energy is 0.18 eV or less. 9. The method of claim 8,
A method for producing a sulfide-based solid electrolyte, characterized in that the lithium ion conductivity at 0 °C to 10 °C is 6 mS/cm or more. 9. The method of claim 8,
The starting material is pulverized with a ball-milling,
A method for producing a sulfide-based solid electrolyte, wherein the grinding is performed repeatedly at 400 rpm to 600 rpm for 10 to 30 minutes and then left for 30 to 50 minutes. 16. The method of claim 15,
A method for producing a sulfide-based solid electrolyte in which the starting material is pulverized by repeating 50 to 100 times. 9. The method of claim 8,
A method for producing a sulfide-based solid electrolyte by heat-treating the pulverized product in a powder state. 9. The method of claim 8,
A method for producing a sulfide-based solid electrolyte by heat-treating the pulverized product in a vacuum state. 9. The method of claim 8,
A method for producing a sulfide-based solid electrolyte by heat-treating the pulverized product at a temperature of 400° C. to 600° C. for 3 hours to 10 hours. 20. The method of claim 19,
A method for producing a sulfide-based solid electrolyte in which the pulverized material is heated from room temperature to a temperature of 400° C. to 600° C. at a temperature increase rate of 1° C./min to 5° C./min for heat treatment of the pulverized product.

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