KR20240020920A - Sulfide type solid electrolyte, its manufacturing method, and lithium secondary battery including thereof - Google Patents

Abstract

The present invention relates to a sulfide-based solid electrolyte used in all-solid-state lithium secondary batteries and a manufacturing method thereof, and provides a wet synthesis method that has the advantage of enabling mass production compared to conventional mechanical milling methods. Furthermore, by forming a precipitate during wet synthesis, removing the remaining supernatant, and then heat-treating the precipitate to produce a sulfide-based solid electrolyte, a sulfide-based solid electrolyte with fewer impurities, smaller primary particle diameter, and excellent ionic conductivity compared to the conventional wet synthesis method. A solid electrolyte can be produced.

Description

Sulfide-based solid electrolyte, its manufacturing method, and lithium secondary battery including the same {Sulfide type solid electrolyte, its manufacturing method, and lithium secondary battery including the same}

The present invention relates to a sulfide-based solid electrolyte, a method of manufacturing the same, and a lithium secondary battery containing the same.

Recently, demand for energy storage devices with safe, high capacity, and high energy density, such as energy storage systems (ESS) and electric vehicles, is increasing. Lithium secondary batteries containing conventionally used organic liquid electrolytes have problems such as electrolyte depletion or gas generation, which limits the design of the maximum operating voltage. When such problems occur, safety issues arise due to the flammable electrolyte. It can happen. In addition, especially when using lithium metal as a negative electrode, problems such as reduced battery life, short circuit, and heat generation may be further accelerated due to the generation of lithium dendrites.

To solve the above problems, lithium secondary batteries using an all-solid electrolyte are attracting attention. The all-solid electrolyte does not deplete the electrolyte, generates less gas, has a wide potential window, which allows the maximum operating voltage of the battery to be higher, and has excellent physical properties, so it can suppress dendrite growth.

When a solid electrolyte is manufactured using a dry ball mill process, primary particles are formed small and the surface area is increased, resulting in high ionic conductivity, but mass production is not possible. On the other hand, when manufactured using a wet stirring process, primary particles are formed somewhat larger and ionic conductivity may be lower, but mass production is possible.

The present invention seeks to provide an electrolyte that overcomes the disadvantages listed above and excludes elements that may adversely affect the size and ionic conductivity of primary particles in the wet stirring process.

It is known that sulfide-based, oxygen-based and phosphoric acid-based materials can be used as such solid electrolytes, and the present invention seeks to provide a wet stirring manufacturing method for mass production of high-quality electrolytes with the structural formula of Li ₆ PS ₅ Cl among sulfide-based electrolytes. do.

(0001) Sunho Choi, Jiu Ann, Jiyae Do, Seungwoo Lim, Chanhwi Park, and Dongwook Choi, Application of Rod-Like Li6PS5Cl Directly Synthesized by a Liquid Phase Process to Sheet-Type Electrodes for All-Solid-State Lithium Batteries, Journal of The Electrochemical Society, 2019, 166 (3), A5193-A5200. (0002) Zhixia Zhang, Long Zhang, Yanyan Liu, Xinlin Yan, Bo Xu, and Li-min Wang, One-step solution process toward formation of Li6PS5Cl argyrodite solid electrolyte for all-solid-state lithium-ion batteries, Journal of Alloys and Compounds, 2020, 812, 152103-152110. (0003) Chuang Yu, Swapna Ganapathy, Jart Hageman, Lambert van Eijck, Ernst van Eck, Long Zhang, Tammo Schwietert, Shibabrata Basak, Erik M. Kelder, and Marnix Wagemaker, Facile synthesis towards the optimal structure-conductivity characteristics of the argyrodite Li6PS5Cl solid state electrolyte, Applied materials and Interfaces, 2018, 10, 39, 33296-33306. (0004) Chuang Yu, Lambert van Eijck, Swapna Ganapathy, Marnix Wagemaker, Synthesis, structure and electrochemical performance of the argyrodite Li6PS5Cl solid electrolyte for Li-ion solid state batteries, Electrochemical Acta, 2016, Vol. 215, 93-99.

In order to solve the above problems, the purpose of the present invention is to provide a sulfide-based solid electrolyte, a method for manufacturing the same, and a lithium secondary battery containing the same.

In order to solve the above problems, the present invention provides a method for producing a sulfide-based solid electrolyte. The manufacturing method specifically includes (A) mixing Li ₂ S and LiCl powder and adding it to ethyl acetate to prepare a first mixture; (B) adding P ₂ S ₅ dropwise to the first mixture and stirring to prepare a second mixture; (C) finishing stirring the second mixture and leaving it to form a precipitate; (D) removing the supernatant excluding the precipitate; and (E) heat treating the precipitate.

In the method for producing the sulfide-based solid electrolyte, 50 to 75 mL of ethyl acetate may be mixed with respect to 1 g of the total weight of the Li ₂ S, LiCl, and P ₂ S ₅ powders.

In step (A), the molar ratio when mixing Li ₂ S and LiCl may be 1:0.1 to 0.8.

In step (A), the preparation of the first mixture may be performed by stirring for 0.5 to 2 hours.

In the step (B), the molar ratio when mixing P ₂ S ₅ may be 1:0.1 to 0.4 with respect to Li ₂ S included in the first mixture.

In step (B), the preparation of the second mixture may be performed by stirring for 18 to 30 hours.

In step (C), the precipitate may be formed by settling the second mixture for 20 to 40 minutes per 1 g of weight of the second mixture.

The present invention provides a sulfide-based solid electrolyte prepared according to the manufacturing method described above.

The sulfide-based solid electrolyte may have a chemical formula of Li ₆ PS ₅ Cl.

The sulfide-based solid electrolyte may be characterized by containing primary particles with an average size of 1 to 2 ㎛.

At this time, the sulfide-based solid electrolyte may be characterized in that the primary particles are composed of secondary particles agglomerated.

The ion conductivity of the sulfide-based solid electrolyte may be 2.00 to 3.00 mS/cm at room temperature.

The sulfide-based solid electrolyte may be characterized as having an agyrhodite phase.

The sulfide-based solid electrolyte may be characterized as having a thickness of 10 to 300 μm.

The sulfide-based solid electrolyte may have an electrochemical window of 0.0 to +5.0 V relative to Li/Li ⁺ .

The sulfide-based solid electrolyte may have an F-43m cubic space group.

Additionally, the present invention provides a lithium secondary battery including the sulfide-based solid electrolyte.

The sulfide-based solid electrolyte according to the present invention has excellent ionic conductivity, excellent thermal stability, and excellent mechanical properties, thereby suppressing the growth of dendrite phases. In addition, the method for producing a sulfide-based solid electrolyte provided by the present invention is characterized by easy mass production, a simple process, and very little process residue or impurities.

Figure 1 is a schematic diagram showing a method for producing a sulfide-based solid electrolyte provided by the present invention.
Figure 2 is a photograph taken with a SEM (Scanning Electron Microscope) of the primary particles of the sulfide-based solid electrolyte according to the present invention, a) is an example, b) is Comparative Example 1, c) is Comparative Example 2, and d) is This is Comparative Example 3.
Figure 3 shows the results of measuring EIS (Electrochemical Impedance Spectroscopy) and calculating electrical conductivity of the sulfide-based solid electrolyte pellet according to the present invention, a) is Example, b) is Comparative Example 1, and c) is Comparative Example. 2, d) is Comparative Example 3.
Figure 4 compares the results of d) is Comparative Example 3.

Hereinafter, the manufacturing method of the sulfide-based solid electrolyte according to the present invention, the sulfide-based solid electrolyte, and the lithium secondary battery containing the same will be described in detail. The drawings introduced below are provided as examples so that the idea of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, if there is no other definition in the technical and scientific terms used in the present invention, they have the meanings commonly understood by those skilled in the art in the technical field to which this invention pertains, and the present invention is described in the following description and accompanying drawings. Descriptions of known functions and configurations that may unnecessarily obscure the gist of are omitted.

In order to solve the above problems, the present invention provides a method for producing a sulfide-based solid electrolyte. Specifically, the manufacturing method includes (A) mixing Li ₂ S and LiCl powder and adding it to ethyl acetate to prepare a first mixture; (B) adding P ₂ S ₅ dropwise to the first mixture and stirring to prepare a second mixture; (C) completing the stirring of the second mixture and leaving it to form a precipitate; (D) removing the supernatant excluding the precipitate; and (E) heat treating the precipitate.

In the method for producing the sulfide-based solid electrolyte, the manufacturing processes in the first (A) step, (B) step, and (C) step may be characterized in that they are performed according to the following reaction formula.

[Reaction formula]

5Li ₂ S+2LiCl+P ₂ S ₅ *2Li ₆ PS ₅ Cl

In the method for producing the sulfide-based solid electrolyte, 50 to 75 mL of ethyl acetate may be mixed with respect to 1 g of the total weight of the Li ₂ S, LiCl, and P ₂ S ₅ powder. The above ratio is intended to prevent deterioration of miscibility due to precipitation of substances during the wet manufacturing process and to facilitate subsequent separation from precipitates, and is preferably the combined weight of the Li ₂ S, LiCl and P ₂ S ₅ powders. Per 1g, 55 to 70 mL of ethyl acetate may be mixed, more preferably 60 to 65 mL.

In step (A), the molar ratio when mixing Li ₂ S and LiCl may be 1:0.1 to 0.8. At this time, the molar ratio may preferably be 1:0.2 to 0.6.

In step (A), the preparation of the first mixture may be performed by stirring for 0.5 to 2 hours. At this time, for uniform mixing, it is recommended to stir for more than 0.75 hours. If it exceeds 1.5 hours, the efficiency compared to the time invested is minimal, so the preparation of the first mixture may be preferably performed by stirring for 0.75 to 1.5 hours. there is. By preparing the first mixture by mixing Li ₂ S and LiCl before adding P ₂ S _{5 ,} the yield of the process can be improved compared to the case of simply mixing the materials.

In the step (B), the molar ratio when mixing P ₂ S ₅ may be 1:0.1 to 0.4 with respect to Li ₂ S included in the first mixture. At this time, the ratio may preferably be 1:0.15 to 0.35. By manufacturing the sulfide-based solid electrolyte at this molar ratio, impurities in the sulfide-based solid electrolyte can be minimized.

In step (B), the preparation of the second mixture may be carried out by stirring for 18 to 30 hours. At this time, it may be preferably stirred for 20 to 28 hours.

In step (C), the precipitate may be formed by leaving the second mixture for more than 15 minutes. At this time, the degree of precipitate formation may vary depending on the amount of the second mixture, but precipitation can be completed by leaving it for 20 to 40 minutes per gram of the second mixture.

In step (C), after the precipitate is formed, a supernatant may be formed. At this time, the supernatant refers to a liquid whose main component is the ethyl acetate and which includes unreacted substances and impurities. The volume of the supernatant may be 70 to 90% of the initial volume of ethyl acetate used in step (A).

In the (D) step, by removing the supernatant, the time required for drying in the subsequent (E) step can be shortened, while the electrochemical properties of the sulfide-based solid electrolyte can be further improved.

In step (E), the heat treatment may be performed after drying the precipitate in an argon atmosphere within a temperature range of 75 to 150° C. for 0.5 to 2.0 hours. Specifically, the heat treatment may be performed at 400 to 700°C for 3 to 7 hours. At this time, the temperature may be increased from room temperature to the heat treatment temperature at a rate of 5°C per minute.

The present invention provides a sulfide-based solid electrolyte prepared according to the manufacturing method described above.

The sulfide-based solid electrolyte may have a chemical formula of Li ₆ PS ₅ Cl.

The sulfide-based solid electrolyte may be characterized by containing primary particles with an average size of 1 to 2 ㎛. Specifically, in the method for producing a sulfide-based solid electrolyte as described above, by removing the supernatant and then performing drying and heat treatment, the average size of the primary particles can be reduced, the density of the electrolyte can be increased, and ionic conductivity can be improved.

At this time, the primary particles may aggregate to form secondary particles. The sulfide-based solid electrolyte provided by the present invention is characterized by using such secondary particles.

The ion conductivity of the sulfide-based solid electrolyte may be 2.00 to 3.00 mS/cm at room temperature. At this time, the ionic conductivity may be measured through EIS (Electrochemical Impedance Spectroscopy) by manufacturing the sulfide-based solid electrolyte pellet.

The sulfide-based solid electrolyte may be characterized as having an argyrodite phase. At this time, the agyrhodite phase has a crystal structure characterized by very high conductivity even at room temperature, and may be formed by the manufacturing method as described above. Additionally, the sulfide-based solid electrolyte may have an F-43m cubic space group.

The sulfide-based solid electrolyte may be characterized as having a thickness of 10 to 300 μm. At this time, the thickness refers to the thickness of the sulfide-based solid electrolyte composed of secondary particles as described above.

The sulfide-based solid electrolyte may have an electrochemical window of 0.0 to +5.0 V relative to Li/Li ⁺ . At this time, the potential window means that electrochemical oxidation or reduction of the electrolyte does not occur when the potential is adjusted within the above-described potential value.

Additionally, the present invention provides a lithium secondary battery including the sulfide-based solid electrolyte.

The lithium secondary battery may include a positive electrode and a negative electrode.

The positive electrode may include a positive electrode active material, a conductive material, a binder, and a positive electrode current collector.

The positive electrode active material is a metal oxide containing lithium, specifically LiFePO ₄ , LiMnPO ₄ , LiCoPO ₄ , LiFe _1-x M _x PO ₄ (M is a divalent or trivalent transition metal), LiCoO ₂ , LiMnO ₂ , LiNiO ₂ LiMn ₂ O ₄ , LiNi _1-x Co _x O ₂ , LiNi _x Co _y Mn _z O ₂ (x+y+z=1), LiNi _x Co _y Al _z O ₂ (x+y+z=1) , LiNi _x Mn _y Mt _z O ₂ (x+y+z=1, Mt is a divalent or trivalent transition metal ₎ , Li _1.2 Ni _0.13 Co _{0.13-x Mn 0.54 Al} (x, y are real numbers independent of each other from 0 to 0.05), Li _1.2 Mn _(0.8-a) Mt _a O ₂ (Mt is a divalent or trivalent transition metal), a(Li ₂ MnO ₃ )*b(LiNi _x Co _y Mn _z O ₂ )(a+b=1, x+y+z=1), Li ₂ Nt _1-x Mt _x O ₃ (Nt is a divalent, trivalent or tetravalent transition metal, Mt is divalent or trivalent transition metal), Li _1+x Nt _yz Mt _z O ₂ (Nt is Ti or Nb, Mt is V, Ti, Mo or W), Li _x Mt _2-x O ₂ (Mt is Ti, Transition metal oxides containing lithium, such as transition metals such as Zr, Nb, Mn, etc.) and Li ₂ O/Li ₂ Ru _1-x Mt _x O ₃ (Mt is a transition metal such as Ti, Zr, Nb, Mn, etc.) Any one or a mixture of two or more selected from the group may be used, but this is only an example and is not necessarily limited thereto.

The conductive material is used to provide conductivity to the electrode, and is used to have excellent chemical stability and electronic conductivity. Specific examples include graphite, carbon black, super blood, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, carbon fiber, carbon nanotube, carbon nanowire, graphene, and graphitized mesocarbon microbeads. , carbon-based materials such as fullerene and amorphous carbon; Metal powders or metal fibers such as copper, nickel, aluminum, and silver; Conductive whiskers such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; and conductive polymers such as polyphenylene derivatives. One or a mixture of two or more of these may be used, but this is only an example and is not necessarily limited thereto.

The binder provides adhesion between the positive electrode active material, the conductive material, and the positive electrode current collector. Specific examples include polyvinylidene fluoride (PVdF), polyimide (PI), fluoropolyimide (FPI), and polyacrylic acid (PAA). , polyvinyl alcohol (PVA), carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone (PVP), tetrafluoroethylene (PTFE), polyethylene, polypropylene, polyurethane, Examples include ethylene-propylene-diene polymer (EPDM), sulfonated ethylene-propylene-diene polymer (S-EPDM), styrene-butadiene rubber (SBR), fluorine rubber or copolymers thereof, algin, etc. Any one or more selected may be used, but this is only an example and is not necessarily limited thereto.

The positive electrode current collector provides an electrical passage between the positive electrode active material and the power source, and may be made of aluminum processed into a form such as aluminum foil or aluminum mesh.

The negative electrode may include a negative electrode active material, a conductive material, a binder, and a negative electrode current collector.

The negative electrode active material is a material capable of storing lithium ions, and includes carbon-based materials such as graphite, activated carbon, hard carbon, and soft carbon; and lithium metal; Any one selected from among may be used, but this is only an example and is not necessarily limited thereto.

Since the conductive material and binder are the same as described above, redundant description will be omitted.

The negative electrode current collector provides an electrical passage between the negative electrode active material and the power source, and may be made of copper processed into a form such as copper foil or copper mesh.

Hereinafter, the method for producing a sulfide-based solid electrolyte according to the present invention and the sulfide-based solid electrolyte produced thereby will be described in more detail through examples. However, the following examples are only a reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Additionally, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in the description herein is merely to effectively describe particular embodiments and is not intended to limit the invention. Additionally, the unit of additives not specifically described in the specification may be weight percent.

[Example]

Li ₂ S, LiCl and P ₂ S ₅ powders were prepared at a molar ratio of 5:2:1. Li ₂ S and LiCl were first added using 62.1 mL of ethyl acetate per 1 g of the total weight of the powder as a solvent and stirred for 1 hour to form a first mixture. P ₂ S ₅ was continuously added to the first mixture and stirred for 23 hours to form a second mixture.

The second mixture after complete stirring was left to form a precipitate, and the supernatant was removed to obtain a precipitate. The precipitate was dried at 100°C for 1 hour in a glove box in an argon atmosphere, the temperature was raised from room temperature to 550°C at a rate of 5°C per minute, and then the dried precipitate was heat treated at 550°C for 5 hours to form a sulfide-based precipitate. A solid electrolyte was prepared.

[Comparative Example 1]

All processes were performed in the same manner as in the example, but the supernatant was not removed.

[Comparative Example 2]

All processes were performed in the same manner as in the example, but 30% of the supernatant was synthesized together.

[Comparative Example 3]

All processes were performed in the same manner as in the example, but 60% of the supernatant was synthesized together.

[Characteristic evaluation method]

A. Surface observation

Referring to Figure 2, you can see SEM (Scanning Electron Microscope) photos of the primary particles of Examples and Comparative Examples 1 to 3. Referring to Figure 2a, it can be seen that the average size of the primary particles in the example was 1.62㎛. Referring to Figures 2b to 2d, the primary particles of Comparative Example 1 had an average size of 2.62㎛, the primary particles of Comparative Example 2 had an average size of 1.71㎛, and the primary particles of Comparative Example 3 had an average size of 2.33㎛, and the supernatant was It can be seen that the size of the primary particles is larger when included. The smaller the average size of the primary particles of a solid electrolyte, the greater the reaction surface area, and generally good ionic conductivity. Therefore, when observing the surface, it can be seen that it is most advantageous to synthesize a solid electrolyte using only sediment.

B. EIS (Electrochemical Impedance Spectroscopy) measurement

Electrochemical Impedance Spectroscopy (EIS) was used to measure the ionic conductivity of the solid electrolyte. To create a compression cell, solid electrolyte powder was pressed at 40 MPa to produce a circular pellet with a diameter of 1 cm and a thickness of approximately 0.06 cm. Stainless steel ion blocking electrodes were placed on both the top and bottom sides of the solid electrolyte to create an ion-blocking cell that is compressed together with the solid electrolyte inside the pressure cell. To evaluate the ionic conductivity of the cell, EIS was measured with alternating current in the range of 100Hz to 7MHz. Resistance is derived by measuring the diameter of the semicircle in the graph resulting from this, and ionic conductivity is obtained using the following calculation formula.

[formula]

In the above calculation formula, σ means ionic conductivity, l means the thickness of the cell, A means the area of the cell, and R means the resistance of the cell.

Referring to Figure 3, the EIS measurement results of Examples and Comparative Examples 1 to 3 can be confirmed. When the x-axis intercept of the graph was obtained to determine the ionic conductivity, the example was found to be 21.61Ω, Comparative Example 1 was found to be 61Ω, Comparative Example 2 was found to be 22Ω, and Comparative Example 3 was found to be 42Ω.

Converting this to ionic conductivity using the electrolyte pellet area of 0.7854cm ² , Example 2 was 2.36mS/cm, Comparative Example 1 was 1.25mS/cm, Comparative Example 2 was 2.31mS/cm, and Comparative Example 3 was 1.82mS/cm. It appeared in cm. As described above, when the supernatant was removed, the ionic conductivity tended to be higher as the average size of the primary particles became smaller.

C. Crystal structure analysis

Referring to Figure 4, the XRD (X-ray Diffraction) measurement results of Examples and Comparative Examples 1 to 3 can be confirmed. Referring to FIG. 4A, in the example, a trace amount of Li ₂ S, a precursor, remained, but Li ₆ PS ₅ Cl, an argyrodite phase, was synthesized.

Referring to Figure 4b, the precursors Li ₂ S, P ₂ S ₅ and LiCl appear to remain, indicating that unreacted substances remain in the supernatant. In addition, referring to Figure 4c, the precursor Li ₂ S remained, and the residual amount was higher than that of the example, and referring to Figure 4d, Li ₂ S, P ₂ S ₅ and LiCl all remained, but a comparison in which all supernatants were synthesized together. A smaller fraction of impurities was detected than in Example 1.

These results show that the content of impurities increases as the amount of supernatant added increases, and that it is more advantageous to manufacture a sulfide-based solid electrolyte using only the precipitate.

Although the present invention has been described through specific details and limited examples as described above, these are provided only to facilitate an overall understanding of the present invention, and the present invention is not limited to the above examples, and the field to which the present invention pertains is not limited to the above-described examples. Those skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

Claims (16)

(A) mixing Li ₂ S and LiCl powder and adding them to ethyl acetate to prepare a first mixture;
(B) adding P ₂ S ₅ dropwise to the first mixture and stirring to prepare a second mixture;
(C) terminating stirring of the second mixture and forming a precipitate;
(D) removing the supernatant excluding the precipitate; and
(E) heat treating the precipitate;
Method for producing a sulfide-based solid electrolyte comprising. According to paragraph 1,
A method for producing a sulfide-based solid electrolyte in which 50 to 75 mL of ethyl acetate is mixed with respect to 1 g of the total weight of the Li ₂ S, LiCl, and P ₂ S ₅ powder. According to paragraph 1,
In step (A), the molar ratio of Li ₂ S and LiCl when mixed is 1:0.1 to 0.8. According to paragraph 1,
In step (A), the preparation of the first mixture is carried out by stirring for 0.5 to 2 hours. According to paragraph 1,
In the step (B), the molar ratio when mixing P ₂ S ₅ is 1:0.1 to 0.4 with respect to Li ₂ S included in the first mixture. According to paragraph 1,
In step (B), the preparation of the second mixture is carried out by stirring for 18 to 30 hours. According to paragraph 1,
In step (C), the precipitate is formed by precipitating the second mixture for 20 to 40 minutes per 1 g of weight of the second mixture. A sulfide-based solid electrolyte prepared according to the method for producing a sulfide-based solid electrolyte according to any one of claims 1 to 7,
A sulfide-based solid electrolyte having the chemical formula Li ₆ PS ₅ Cl. According to clause 8,
The sulfide-based solid electrolyte is characterized in that it contains primary particles with an average size of 1 to 2 ㎛. According to clause 9,
The sulfide-based solid electrolyte is characterized in that it is composed of secondary particles in which the primary particles are aggregated. According to clause 8,
A sulfide-based solid electrolyte, characterized in that the ion conductivity of the sulfide-based solid electrolyte is 2.00 to 3.00 mS/cm at room temperature. According to clause 8,
The sulfide-based solid electrolyte has a potential window (electrochemical window) of 0.0 to +5.0V compared to Li/Li ⁺ . According to clause 8,
The sulfide-based solid electrolyte is characterized in that the thickness is 10 to 300㎛. According to clause 8,
The sulfide-based solid electrolyte is characterized in that the sulfide-based solid electrolyte has an agyrhodite phase. According to clause 8,
The sulfide-based solid electrolyte has an F-43m cubic space group. A lithium secondary battery comprising a sulfide-based solid electrolyte manufactured according to the method for producing a sulfide-based solid electrolyte according to any one of claims 1 to 7.