Method for manufacturing sulfide-based solid electrolyte

Abstract

The present invention relates to a method for manufacturing a sulfide-based solid electrolyte, the method comprising the steps of: (S1) preparing a precursor solution by adding a precursor containing an alkali metal sulfide, a phosphorus sulfide, and a halogen compound to a solvent; (S2) performing first milling on the precursor solution to prepare an intermediate product; (S3) adding a dispersant after the step (S2) and then performing second milling to adjust the particle size of the intermediate product; (S4) drying the particle size-adjusted intermediate product after the step (S3); and (S5) heat-treating the dried intermediate product, wherein the dispersant is an aliphatic compound, and the mass ratio of the solvent and the dispersant is 75: 1 to 150: 1.

Description

Method for manufacturing sulfide-based solid electrolyte

[0001] The present invention relates to a method for manufacturing a sulfide-based solid electrolyte.

[0002] Recent reports of explosion risks in batteries using liquid electrolytes have led to active development of all-solid-state secondary batteries. All-solid-state secondary batteries are composed entirely of solid materials, specifically those using solid electrolytes. These all-solid-state secondary batteries are safe, eliminating the risk of explosion due to electrolyte leakage, and offer the advantage of being easy to manufacture in thinner sizes.

[0003] However, solid electrolytes have lower ionic conductivity than liquid electrolytes, and have problems such as resistance occurring at the interface between solid electrolyte particles or resistance occurring at the interface with other solid particles, such as positive electrode active materials in the battery, which reduces ionic conductivity.

[0004] Among solid electrolytes, active research is being conducted on sulfide-based solid electrolytes, which boast relatively high ionic conductivity. Sulfide-based solid electrolytes can be divided into catholyte / anolyte electrolytes used with electrodes and separator electrolytes. These two purposes require different conditions and particle sizes, and therefore, particle size control processes are often performed after the synthesis process.

[0005] However, if a separate particle size control process is included, the process becomes complex and many process variables are created, so a continuous process is required.

[0006] The problem to be solved by the present invention is to provide a method for manufacturing a sulfide-based solid electrolyte that can minimize process variables by optimizing process steps as well as minimizing the decrease in ionic conductivity.

[0007] According to one aspect of the present invention, a method for producing a sulfide-based solid electrolyte is provided, comprising: a step (S1) of preparing a precursor solution by introducing a precursor including an alkali metal sulfide, a phosphorus sulfide, and a halogen compound into a solvent; a step (S2) of first milling the precursor solution to produce an intermediate product; a step (S3) of adjusting the particle size of the intermediate product by introducing a dispersant after the step (S2) and then second milling; a step (S4) of drying the particle size-controlled intermediate product after the step (S3); and a step (S5) of heat-treating the dried intermediate product; wherein the dispersant is an aliphatic compound, and a mass ratio of the solvent and the dispersant is 75:1 to 150:1.

[0008] According to one embodiment of the present invention, a method for producing a sulfide-based solid electrolyte is provided, wherein the alkali metal sulfide includes lithium sulfide (Li2S), sodium sulfide (Na2S), or potassium sulfide (K2S).

[0009] According to one embodiment of the present invention, a method for producing a sulfide-based solid electrolyte is provided, wherein the halogen compound includes at least one material selected from the group consisting of lithium bromide (LiBr), lithium chloride (LiCl), lithium iodide (LiI), and lithium fluoride (LiF).

[0010] According to one embodiment of the present invention, a method for producing a sulfide-based solid electrolyte is provided, wherein the solvent is at least one selected from the group consisting of heptane, hexane, cyclohexane, and toluene.

[0011] According to one embodiment of the present invention, in claim 1,

[0012] Each of the above steps (S2) and (S3) provides a method for manufacturing a sulfide-based solid electrolyte that can be performed for 5 to 40 hours.

[0013] According to one embodiment of the present invention, each of the steps (S2) and (S3) provides a method for manufacturing a sulfide-based solid electrolyte, which can be performed using balls in a planetary ball mill method, an attrition mill method, a SPEX mill method, a ball mill method, or a bead mill method.

[0014] According to one embodiment of the present invention, each of the steps (S2) and (S3) provides a method for manufacturing a sulfide-based solid electrolyte by milling while adjusting the mass ratio of the precursor and the ball to 1:10 to 1:20.

[0015] According to one embodiment of the present invention, a method for manufacturing a sulfide-based solid electrolyte is provided, wherein the diameter of the ball used in the step (S2) is 0.5 mm to 5 mm, and the diameter of the ball used in the step (S3) is 0.1 mm to 1 mm.

[0016] According to one embodiment of the present invention, a method for producing a sulfide-based solid electrolyte is provided, wherein the dispersant is at least one selected from the group consisting of dibutyl ether (DBE), diglyme, tetraglyme, dimethoxyethane (DME), and combinations thereof.

[0017] According to one embodiment of the present invention, a method for manufacturing a sulfide-based solid electrolyte is provided, wherein the average particle size controlled by the step (S3) is 0.1 µm to 5 µm.

[0018] According to one embodiment of the present invention, a method for manufacturing a sulfide-based solid electrolyte is provided in which the step (S4) of drying the particle-sized intermediate product is performed at 60°C to 100°C.

[0019] According to one embodiment of the present invention, a method for manufacturing a sulfide-based solid electrolyte is provided, in which the step (S5) of heat-treating the dried intermediate product is performed by heating the product from room temperature to a heat treatment temperature according to the following equation 1 and then holding the temperature for 10 to 20 seconds.

[0020] [Formula 1]

[0021] T g + 50℃ ≤ T ≤ T g + 130℃

[0022] The above T g is the glass transition temperature of the above dried intermediate product.

[0023] According to one embodiment of the present invention, a method for manufacturing a sulfide-based solid electrolyte is provided, in which the step (S5) of heat-treating the dried intermediate product is performed for 30 to 50 seconds.

[0024] According to one embodiment of the present invention, a method for manufacturing a sulfide-based solid electrolyte is provided, which further includes a step (S2′) of drying the intermediate product before the step (S3); wherein each of the step (S2′) and the step (S4) is performed at a temperature of 60°C to 100°C.

[0025] According to one embodiment of the present invention, a method for manufacturing a sulfide-based solid electrolyte is provided, further comprising a step (S6) of cooling a product obtained by the heat treatment, wherein the cooling is performed within 1 minute.

[0026] According to one embodiment of the present invention, a method for manufacturing a sulfide-based solid electrolyte having a glass-ceramic structure is provided.

[0027] A method for manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention can rapidly increase the temperature by directly transferring heat energy to a precursor to exhibit a high ionic conductivity phase, thereby minimizing a decrease in ionic conductivity and volatilization of sulfur.

[0028] In addition, the method for manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention can optimize the process steps and minimize process variables resulting therefrom by performing a particle size control step immediately after the raw material mixing step through a wet process.

[0029] Figure 1 is a flowchart showing a method for manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention.

[0030] Figure 2 is a flowchart showing a method for manufacturing a sulfide-based solid electrolyte according to another embodiment of the present invention.

[0031] Figure 3 is a flowchart showing a method for manufacturing a sulfide-based solid electrolyte according to another embodiment of the present invention.

[0032] Figure 4 is a graph showing the DSC results of an intermediate product according to Evaluation Example 1.

[0033] Figure 5 is a graph showing the XRD results of an intermediate product according to Evaluation Example 1 and a sulfide-based solid electrolyte manufactured according to Comparative Examples 1 and 2.

[0034] Figure 6 is a graph showing the XRD results of sulfide-based solid electrolytes manufactured according to Examples 1 to 5.

[0035] Figure 7 is a graph showing the XRD results of a sulfide-based solid electrolyte manufactured according to Example 5 and Comparative Example 3.

[0036] Figure 8 is a graph showing the XRD results of sulfide-based solid electrolytes manufactured according to Examples 6 and 7 and Comparative Example 4.

[0037] The present invention is capable of various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, as well as the methods for achieving them, will become clearer with reference to the embodiments described in detail below, along with the drawings. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various forms.

[0038] In the examples below, the terms first, second, etc. are not used in a limiting sense, but are used for the purpose of distinguishing one component from another.

[0039] In the examples below, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0040] In the examples below, terms such as “include” or “have” mean that a feature or component described in the specification is present, and do not preclude the possibility that one or more other features or components may be added.

[0041] In the following examples, when a part such as a film, region, component, etc. is said to be on or above another part, it includes not only a case where it is directly on top of the other part, but also a case where another film, region, component, etc. is interposed in between.

[0042] For convenience of explanation, the sizes of components in the drawings may be exaggerated or reduced. For example, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to what is shown.

[0043] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings, and when describing with reference to the drawings, identical or corresponding components will be given the same drawing reference numerals.

[0044] FIG. 1 is a flowchart illustrating an example of a method for manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention.

[0045] Referring to FIG. 1, a method for manufacturing a sulfide-based solid electrolyte may include a step (S1) of preparing a precursor solution by adding a precursor including an alkali metal sulfide, a phosphorus sulfide, and a halogen compound to a solvent, a step (S2) of first milling the precursor solution to prepare an intermediate product, a step (S3) of adjusting the particle size of the intermediate product by adding a dispersant after the step (S2) and then second milling, a step (S4) of drying the intermediate product with adjusted particle size after the step (S3), and a step (S5) of heat-treating the dried intermediate product.

[0046] In the step (S1) of preparing a precursor solution, the precursor may include an alkali metal sulfide, a phosphorus sulfide, or a halide. The alkali metal sulfide is not particularly limited as long as it is used in the art for producing a sulfide-based solid electrolyte. For example, the alkali metal sulfide may be lithium sulfide (Li2S), sodium sulfide (Na2S), or potassium sulfide (K2S), and preferably lithium sulfide (Li2S).

[0047] The phosphosulfide is not particularly limited as long as it is used in the manufacture of sulfide-based solid electrolytes in the art. For example, the phosphosulfide may be diphosphorus pentasulfide (P2S5).

[0048] The halogen compound is not particularly limited as long as it is used in the art for manufacturing a sulfide-based solid electrolyte. For example, it may include one or more substances selected from the group consisting of lithium bromide (LiBr), lithium chloride (LiCl), lithium iodide (LiI), and lithium fluoride (LiF). Alternatively, the halogen compound may include two substances, for example, lithium bromide (LiBr) and lithium iodide (LiI) may be used together.

[0049] If the alkali metal sulfide is lithium sulfide (Li2S), the phosphorus sulfide is diphosphorus pentasulfide (P2S5), and the halogen compound is lithium bromide (LiBr) and lithium iodide (LiI), there is no particular limitation as long as the amounts are those used in the manufacture of sulfide-based solid electrolytes in the art. For example, the molar ratio of lithium sulfide (Li2S): diphosphorus pentasulfide (P2S5): lithium bromide (LiBr): lithium iodide (LiI) may be 6:2:1:1. The lithium sulfide (Li2S)-phosphorus pentasulfide (P2S5)-based lithium secondary battery solid electrolyte has higher ionic conductivity than the oxide-based solid electrolyte, and therefore, the content of lithium sulfide (Li2S) needs to be about 60 mol% or more in the starting material. However, when the content of lithium sulfide (Li2S) is excessive, as the amount of lithium sulfide (Li2S) remaining in the final glass ceramics increases, the reactivity with moisture and the active material interface increases, and the electrochemical stability decreases. Therefore, the above-described mixing ratio may be the optimal ratio for improving ionic conductivity while reducing the amount of lithium sulfide (Li2S) remaining in the final glass ceramics.

[0050] The solvent can be a nonpolar solvent that dissolves the precursors to prepare a precursor solution. The solvent is not particularly limited as long as it is used in the art for manufacturing sulfide-based solid electrolytes. For example, the solvent may be one or more selected from the group consisting of heptane, hexane, cyclohexane, and toluene.

[0051] The first milling of step (S2) may be a step for synthesizing an intermediate product, and the second milling of step (S3) may be a step for controlling the particle size of the intermediate product.

[0052] The first milling is a synthesis and crushing process that creates PS4 bonds with high energy. For example, the first milling can mill at high energy of 350 to 400 RPM for 24 hours using the P5 model, a mechanical milling equipment from Fritsch, but it is not limited to this as long as it is a method for synthesizing and crushing intermediate products.

[0053] Second milling is a process of controlling the particle size of the intermediate product by milling at low energy with a dispersant. For example, second milling can be performed at low energy of 120 RPM for 12 hours after adding a dispersant, which is a solvent. However, if the method is used to appropriately control the particle size, it is not limited to this.

[0054] Rather than separately recovering or drying the intermediate products formed from the first milling and then performing the second milling again, the second milling process is performed in a single device. In other words, by performing the second milling process immediately after the first milling, a continuous particle size control process can be performed, optimizing the process steps.

[0055] In a method for manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention, the particle size is adjusted by breaking intermediate particles through second milling, and at the same time, the second milling is continuously performed without going through a drying step, so that the surface is maintained in a state where it is not exposed to the atmosphere by a solvent, and the amorphous particles are evenly maintained, so that an atmosphere that facilitates nucleation can be maintained.

[0056] Each of the first milling of step (S2) and the second milling of step (S3) may be performed using balls in a planetary ball mill method, an attrition mill method, a SPEX mill method, a ball milling method, or a bead mill method. The intermediate product produced at this time may be a sulfide-based amorphous solid electrolyte.

[0057] Each of the first milling of step (S2) and the second milling of step (S3) may be performed for 5 to 40 hours. Specifically, the lower limit of the milling time may be 5 hours, 10 hours, 15 hours, or 20 hours, and the upper limit of the milling time may be 40 hours, 35 hours, 30 hours, or 25 hours. If the milling time is less than 5 hours, mixing may not occur properly, making it impossible to manufacture an amorphous solid electrolyte with a consistent composition. If the milling time exceeds 40 hours, there is a concern that the temperature at which crystallinity locally increases may exceed 170°C. Therefore, if the milling time satisfies the above range, an amorphous solid electrolyte with a consistent composition and uniformity can be manufactured.

[0058] The balls used in the first and second milling processes transmit impact energy to the precursor during the synthesis and particle size control of the intermediate product, and the mass and size of the balls can affect the synthesis and particle size control. For example, the balls may include at least one selected from the group consisting of glass, alumina, zirconia, and combinations thereof, and zirconia balls are preferably used.

[0059] The first milling of step (S2) and the second milling of step (S3) can be performed by adjusting the mass ratio of the precursor to the ball to 1:10 to 1:20, respectively. If the mass ratio of the precursor to the ball exceeds the above range, it is difficult to mix the precursor, making it difficult to manufacture a sulfide-based amorphous solid electrolyte that satisfies uniformity. If the mass ratio of the precursor to the ball is less than the above range, it may be difficult to pulverize the precursor. Therefore, if the mass ratio of the precursor to the ball satisfies the above range, mixing and pulverization of the precursor can be sufficiently achieved.

[0060] The diameter of the balls used in step (S2) may be 0.5 mm to 5 mm. The diameter (size) of the balls refers to the average particle size based on the volume average, and specifically, the lower limit of the ball diameter may be 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, or 2.5 mm, and the upper limit of the ball diameter may be 5 mm, 4.5 mm, 4 mm, 3.5 mm, or 3 mm. If the diameter (size) of the balls is outside the above range, sufficient energy is not transferred to the precursor, making it difficult to synthesize. Therefore, if the diameter (size) of the balls satisfies the above range, a lot of energy is applied to the precursor, thereby reducing the crystallinity, thereby synthesizing and pulverizing a sulfide-based solid electrolyte.

[0061] The diameter of the balls used in step (S3) may be 0.1 mm to 1 mm. Specifically, the lower limit of the ball diameter may be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm, and the upper limit of the ball diameter may be 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, or 0.6 mm. If the diameter (size) of the balls exceeds the above range, the average particle size of the intermediate product may be formed to be too large, and if the diameter (size) of the balls is less than the above range, energy is not sufficiently applied to the intermediate product, making it difficult for disintegration and pulverization to occur sufficiently. Therefore, if the diameter (size) of the balls satisfies the above range, a sulfide-based solid electrolyte having an appropriate particle size can be manufactured.

[0062] The average particle size controlled by step (S3) may be 0.1 μm to 5 μm. The particle size may be controlled by adjusting the size of the zirconia balls used and the operating time. Specifically, the lower limit of the average particle size controlled by step (S3) may be 0.1 μm, 0.3 μm, 0.4 μm, 0.7 μm, 0.9 μm, or 1 μm, and the upper limit of the average particle size controlled by step (S3) may be 5 μm, 4.5 μm, 4 μm, 3.5 μm, 3 μm, 2.5 μm, 2 μm, or 1.5 μm.

[0063] If the average particle size controlled by step (S3) exceeds the above range, it may be difficult to achieve a dense state in the battery manufacturing process, and it may be difficult to produce a constant thickness. If the average particle size controlled by step (S3) is less than the above range, it may be difficult to handle in the process, and it may be difficult to form a contact interface with the active material in the electrode layer due to the high specific surface area. Therefore, if the average particle size controlled by step (S3) satisfies the above range, the decrease in ionic conductivity can be minimized by expressing a high ionic conductivity phase even if the heat treatment temperature is lowered compared to a sulfide-based solid electrolyte that has not undergone a particle size control process.

[0064] The average particle size controlled by step (S3) can be measured by a statistical image analysis method using scanning electron microscopy (SEM) analysis, but is not limited thereto as long as the size can be measured.

[0065] A dispersant may be introduced in the particle size control step (S3). The dispersant is introduced during the second milling, and during the second milling, it is adsorbed on the particle surface to prevent reaction with external substances or agglomeration between particles, prevent unnecessary reaction due to frictional heat between precursors, and contribute to fine particle formation. In this case, the grinding efficiency is increased, and a uniform particle size distribution can be obtained. Additionally, since the dispersant is not introduced into the precursor solution from the beginning, it has the advantage of not interfering with the synthesis of intermediate products. If the dispersant is introduced from the beginning, sufficient energy may not be applied to the precursor, making it difficult for the synthesis to proceed sufficiently, and since the particle size may not be properly reduced, it may be difficult to proceed with particle size control while synthesizing the intermediate products.

[0066] The dispersant may be at least one selected from the group consisting of carbonate solvents, ether solvents, nitrile solvents, phosphate solvents, and sulfone solvents, but is not particularly limited as long as it is used in the art for producing sulfide-based solid electrolytes. For example, the dispersant may be at least one selected from the group consisting of dibutyl ether (DBE), diglyme, tetraglyme, dimethoxyethane (DME), and combinations thereof as ether solvents. The dispersant may be an aliphatic compound.

[0067] The mass ratio of the solvent and the dispersant may be from 75:1 to 150:1. Specifically, the lower limit of the mass ratio of the solvent and the dispersant may be 75:1, 80:1, 85:1, 90:1, or 95:1, and the upper limit of the mass ratio of the solvent and the dispersant may be 150:1, 145:1, 140:1, 135:1, 130:1, or 125:1.

[0068] If the mass ratio of the solvent and dispersant exceeds the above range, the concentration of the dispersant is too low, so energy is dispersed, and the energy received by the material during synthesis becomes too low, which may cause a problem of reduced productivity.

[0069] If the mass ratio of the solvent and dispersant is less than the above range, the concentration of the dispersant is too high, so the frictional energy (shear force) by the ball is not properly applied, and the frictional heat increases unnecessarily, making synthesis difficult and the particle size may become unnecessarily large.

[0070] When the mass ratio of the solvent and dispersant satisfies the above range, a uniform particle size distribution can be obtained while having an appropriate particle size distribution.

[0071] Figure 2 is a flowchart showing a method for manufacturing a sulfide-based solid electrolyte according to another embodiment of the present invention.

[0072] A method for manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention may further include a step (S2′) of drying an intermediate product before step (S3), and step (S2′) may be performed at 60°C to 100°C. In this case, since the second milling cannot be performed immediately after the first milling, it may be difficult to achieve a continuous particle size control process.

[0073] Furthermore, when the surface of the intermediate product is dried during the drying process (S2′), the amorphous state is evenly distributed across the particle surface. However, as the glassy state is eroded by the second milling step after drying, nucleation occurs unevenly, and as energy is partially concentrated, nuclei grow, which may lower the expression of the high ionic conductivity phase.

[0074] The step (S4) of drying the particle-sized intermediate product after step (S3) may correspond to a solvent removal process that evaporates the solvent. The drying step may be performed at 60°C to 100°C for a predetermined period of time. For example, drying may be performed using a spray dryer in an inert atmosphere or vacuum drying may be performed.

[0075] Figure 4 is a graph showing the DSC results of an intermediate product according to Evaluation Example 1.

[0076] Referring to Figure 4, the glass transition temperature (T) of the dried intermediate product g ) is about 170℃, and the first crystallization temperature (T c1 ) is about 180℃, and the secondary crystallization temperature (T c2 ) can be confirmed to be about 250℃. That is, even if the intermediate product is dried at a temperature in the above range, the glass transition temperature (T g ) is formed below, the dried intermediate product may be a sulfide-based amorphous solid electrolyte.

[0077] The step (S5) of heat-treating the dried intermediate product is a step of heat-treating a sulfide-based amorphous solid electrolyte to produce a solid electrolyte that is crystallized into a glass crystal, and can be performed by raising the temperature from room temperature to a heat-treatment temperature according to Equation 1 below and then holding the temperature for 10 to 20 seconds. When the heat-treatment is performed for 10 to 20 seconds at a heat-treatment temperature (T) according to Equation 1 below, the volatilization of sulfur can be prevented due to the short heat-treatment time, and the nucleus growth is prevented, so that a high-ionic conductivity phase is expressed in large quantities, thereby minimizing the decrease in ionic conductivity. In addition, since nucleation occurs rather than nucleation, impurities are not generated, so a high-ionic conductivity phase can be generated in large quantities.

[0078] [Formula 1]

[0079] T g + 50℃ ≤ T ≤ T g + 130℃

[0080] The above T g is the glass transition temperature of the above dried intermediate product.

[0081] The above heat treatment temperature (T) is the glass transition temperature (T) of the dried intermediate product. g ) can be determined based on the temperature range, and by controlling the particle size before the heat treatment step, the decrease in ionic conductivity can be minimized even in a relatively low heat treatment temperature range.

[0082] The heat treatment temperature (T) is the glass transition temperature (T g ) is less than , the solid electrolyte does not crystallize properly, so only an amorphous solid electrolyte exists. Since a certain degree of crystallinity is not present, ionic conductivity is not properly displayed.

[0083] The heat treatment temperature (T) is the first crystallization temperature (T c1 ) above, lithium tetrasulfide (Li3PS4), which is the most stable phase in the sulfide-based solid electrolyte, can be generated, and ionic conductivity can be reduced by lithium tetrasulfide (Li3PS4). In addition, the heat treatment temperature (T) is T g+ When the temperature is less than 50℃, it is difficult to provide sufficient energy for nucleation of the intermediate product with only the above heating time (10 to 20 seconds).

[0084] Also, the heat treatment temperature (T) is T g + When the temperature exceeds 130℃, the crystallinity may increase, but the ionic conductivity may decrease as the most stable phase, lithium tetrasulfide (Li3PS4), is generated by nuclei growth along with nuclei formation.

[0085] However, the heat treatment temperature (T) is lower than the secondary crystallization temperature (T c2 ), if the heat treatment temperature (T) satisfies the above range and the heating time (10 to 20 seconds) is satisfied, the most stable phase, lithium tetrasulfide (Li3PS4), may not be generated. Therefore, the method for manufacturing a sulfide-based solid electrolyte according to the present invention can significantly improve the ionic conductivity of the sulfide-based solid electrolyte by preventing the generation of lithium tetrasulfide (Li3PS4), which is the most stable phase.

[0086] The step (S5) of heat-treating the dried intermediate product can be performed for 30 to 50 seconds. This includes the time required to raise the temperature from room temperature to the heat-treatment temperature (T) and the time required to maintain the temperature at the heat-treatment temperature (T). If the temperature-raising time and the holding time satisfy the above ranges, nuclei growth can be prevented, an ionic conductivity phase can be developed, and ionic conductivity can be improved.

[0087] For example, the dried intermediate product can be heated to the heat treatment temperature (T) by performing heat treatment at a heating rate of 6.6°C or more.

[0088] Figure 3 is a flowchart showing a method for manufacturing a sulfide-based solid electrolyte according to another embodiment of the present invention.

[0089] Referring to FIG. 3, a method for manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention may further include a step (S6) of cooling a product obtained by heat treatment, and the cooling may be performed within 1 minute to cool to room temperature (25°C). Since the RTA equipment does not include a refractory and includes a tube containing water, the sample can be taken out and cooled immediately after the heat treatment step is completed. Accordingly, the overall process time can be shortened. At this time, the product may be a sulfide-based solid electrolyte having a glass-ceramic structure.

[0090] As described above, the sulfide-based solid electrolyte manufactured using the method for manufacturing a sulfide-based solid electrolyte according to an embodiment of the present invention can be applied to an all-solid-state battery and used as an electrolyte of the all-solid-state battery.

[0091]

[0092] solid electrolyte

[0093] A sulfide-based solid electrolyte manufactured according to one embodiment of the present invention may have a glass-ceramic structure. The method for manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention enables the control of nuclear growth through thermal energy directly applied to the precursor, thereby being effective in producing glass crystals.

[0094] If the heat treatment step takes a long time, the manufactured sulfide-based solid electrolyte may lose its ionic conductivity and glass properties as crystal nuclei continue to grow during the heat treatment process. However, the sulfide-based solid electrolyte manufactured according to one embodiment of the present invention has a very short heat treatment time, so that the nuclei of the sulfide-based solid electrolyte are prevented from growing, and a high ionic conductivity phase is expressed to a large extent, thereby minimizing the decrease in ionic conductivity.

[0095] In addition, by significantly shortening the heat treatment time, the volatilization of sulfur can be minimized, so that a structurally stable sulfide-based solid electrolyte can be manufactured, and by directly transferring heat energy to the mixture, heat loss to the surroundings can be prevented, so that the heat treatment temperature can be appropriately controlled, and by stopping the transfer of heat energy, cooling is performed immediately, so that rapid cooling to a low temperature of the surroundings is possible, so that the cooling time of the cooling step can be shortened.

[0096] In particular, a sulfide-based solid electrolyte manufactured according to one embodiment of the present invention can have a glass-ceramic structure even when the heat treatment temperature is relatively low by performing a particle size control process before the heat treatment step.

[0097]

[0098] All-solid-state battery

[0099] A method for manufacturing an all-solid-state battery may include a step of manufacturing a sulfide-based solid electrolyte according to one embodiment of the present invention; and a step of manufacturing a cell by laminating a positive electrode, the solid electrolyte, and a negative electrode.

[0100] For example, according to the above manufacturing method, an all-solid-state battery may include a cathode, an anode, and a sulfide-based solid electrolyte layer disposed between the cathode and the anode.

[0101] At this time, the sulfide-based solid electrolyte layer may be a sulfide-based solid electrolyte manufactured using a sulfide-based solid electrolyte manufacturing method according to one embodiment of the present invention.

[0102] The negative electrode may include a negative electrode current collector and a negative electrode active material layer formed on one surface of the negative electrode current collector.

[0103] The negative electrode active material that may be included in the negative electrode active material layer may include at least one selected from the group consisting of lithium (Li), amorphous carbon, gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0104] A binder that may be included in the negative electrode active material layer can improve the bonding between the negative electrode active material and the conductive material and the bonding to the negative electrode current collector. Examples of the negative electrode binder include polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluoroelastomer, and various copolymers thereof.

[0105] A conductive material that can be included in the negative electrode active material layer can be used to further improve the conductivity of the negative electrode active material. The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fiber or metal fiber; metal powders such as fluorocarbon, aluminum, copper, nickel, and silver powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; polyphenylene derivatives, carbon nanotubes, and the like.

[0106] The negative electrode current collector may be made of a material that is conductive and does not react with lithium without causing a chemical change in the battery, and may include various forms such as a film, sheet, foil, net, porous body, foam, non-woven fabric, etc. having fine irregularities formed on the surface. For example, the negative electrode current collector may include at least one selected from the group consisting of copper (Cu), stainless steel (SS), titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni).

[0107] The positive electrode may include a positive electrode current collector and a positive electrode active material layer formed on one surface of the positive electrode current collector.

[0108] The cathode active material that can be included in the cathode active material layer may include at least one selected from lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganese oxide, lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide, but is not necessarily limited thereto, and any cathode active material used in the relevant technical field may be used.

[0109] A binder that can be included in the positive electrode active material layer can improve the bonding between the positive electrode active material and the conductive material, as well as the bonding to the positive electrode current collector. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluoroelastomer, and various copolymers thereof.

[0110] A conductive material that can be included in the positive electrode active material layer can be used to further improve the conductivity of the positive electrode active material. The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fiber or metal fiber; metal powders such as fluorocarbon, aluminum, copper, nickel, and silver powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; polyphenylene derivatives, and carbon nanotubes.

[0111] The positive electrode current collector may be made of stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. In addition, the positive electrode current collector may form fine irregularities on the surface of the positive electrode current collector to increase the adhesion of the positive electrode active material. For example, the positive electrode current collector may be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric.

[0112] Hereinafter, examples are presented to help understand the present invention, but the examples are only illustrative of the present disclosure, and the scope of the present application is not construed as being limited to the examples described below, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of ​​the present disclosure, and it is natural that such changes and modifications fall within the scope of the appended patent claims.

[0113] Example 1: Preparation of solid electrolyte

[0114] A total of 40 g of precursors mixed with lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), lithium bromide (LiBr), and lithium iodide (LiI) in a ratio of 6:2:1:1 were weighed and subjected to high-energy first milling (mechanical milling) for 40 hours using a Fritsch P5 model together with 500 g of 1 mm zirconia balls and 250 cc of heptane, a non-polar solvent.

[0115] Immediately after the first milling, without drying, a dispersant (dibutyl ether) was additionally added to the container and a second milling was performed at 150 rpm for 12 hours using a high-energy mill (Fritsch, P5 line), producing an intermediate product with a particle size of 2 μm. The ratio of heptane solvent to dispersant was 125:1.

[0116] The intermediate product manufactured after the second milling was obtained by vacuum drying at 80°C, and then the zirconia balls were removed through a sieving machine to prepare the intermediate product.

[0117] Afterwards, the prepared intermediate product was subjected to overshooting heat treatment up to 220°C in an RTA device. The RTA device heated at a heating rate of 6.6°C per second, maintained at 220°C for 10 seconds in an inert atmosphere, and then cooled for 60 seconds to produce a sulfide-based solid electrolyte. The total time required for the heat treatment was 49 seconds, and the time required for cooling after heating was 60 seconds. In other words, the total time required for the heat treatment and cooling was 109 seconds.

[0118]

[0119] Example 2: Preparation of solid electrolyte

[0120] A sulfide-based solid electrolyte was manufactured using the same manufacturing method as Example 1, except that the RTA equipment was heated at a heating rate of 6.6°C per second and maintained in an inert atmosphere at a temperature of 240°C for 10 seconds.

[0121]

[0122] Example 3: Preparation of solid electrolyte

[0123] A sulfide-based solid electrolyte was manufactured using the same manufacturing method as Example 1, except that the RTA equipment was heated at a heating rate of 6.6°C per second and maintained in an inert atmosphere at a temperature of 260°C for 10 seconds.

[0124]

[0125] Example 4: Preparation of solid electrolyte

[0126] A sulfide-based solid electrolyte was manufactured using the same manufacturing method as Example 1, except that the RTA equipment was heated at a heating rate of 6.6°C per second and maintained in an inert atmosphere at a temperature of 280°C for 10 seconds.

[0127]

[0128] Example 5: Preparation of solid electrolyte

[0129] A sulfide-based solid electrolyte was manufactured using the same manufacturing method as Example 1, except that the RTA equipment was heated at a heating rate of 6.6°C per second and maintained in an inert atmosphere at a temperature of 300°C for 10 seconds.

[0130]

[0131] Example 6: Preparation of solid electrolyte

[0132] A total of 40 g of precursor mixed with lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), lithium bromide (LiBr), and lithium iodide (LiI) in a ratio of 6:2:1:1 was weighed and subjected to high-energy first milling (mechanical milling) for 40 hours using a Fritsch P5 model together with 500 g of 3 mm zirconia balls and 250 cc of heptane, a non-polar solvent.

[0133] The intermediate product manufactured after the first milling was obtained by vacuum drying at 80°C, and then 3 mm zirconia balls were removed through a sieving machine.

[0134] The dried intermediate product was then added to the container, 500 g of 1 mm zirconia balls and a dispersant (dibutyl ether), and milled a second time at 150 rpm for 12 hours using a high-energy milling machine (Fritsch, P5 line) to produce a 3.7 μm intermediate product. The heptane solvent and dispersant ratio was 125:1.

[0135] The intermediate product manufactured after the second milling was obtained by vacuum drying at 80°C, and then the zirconia balls were removed through a sieving machine to prepare the intermediate product.

[0136] Afterwards, the prepared intermediate product was subjected to overshooting heat treatment up to 220°C in an RTA device. The RTA device heated at a heating rate of 6.6°C per second, maintained at 220°C for 10 seconds in an inert atmosphere, and then cooled for 60 seconds to produce a sulfide-based solid electrolyte. The total time required for the heat treatment was 49 seconds, and the time required for cooling after heating was 60 seconds. In other words, the total time required for the heat treatment and cooling was 109 seconds.

[0137]

[0138] Example 7: Preparation of solid electrolyte

[0139] A sulfide-based solid electrolyte was manufactured using the same manufacturing method as Example 6, except that the RTA equipment was heated at a heating rate of 6.6°C per second and maintained in an inert atmosphere at a temperature of 240°C for 10 seconds.

[0140]

[0141] Comparative Example 1: Preparation of Solid Electrolyte

[0142] A total of 40 g of precursor mixed with lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), lithium bromide (LiBr), and lithium iodide (LiI) in a ratio of 6:2:1:1 was weighed and subjected to high-energy milling (mechanical milling) for 40 hours using a Fritsch P5 model along with 500 g of 3 mm zirconia balls and 250 cc of heptane, a non-polar solvent.

[0143] The intermediate product manufactured after the first milling was obtained by vacuum drying at 80°C, and then the 3 mm zirconia balls were removed through a sieving machine to prepare an intermediate product with a particle size of 12 μm.

[0144] The above-mentioned intermediate product is vitrified at a glassization temperature (T) in a general tube furnace without going through a particle size control process. g) was heat treated up to 170℃. The heating rate was 5℃ per minute and maintained in an inert atmosphere for 12 hours, so the total time required for heat treatment was 749 minutes. The time required for cooling after heating was 1 hour. In other words, the total time required for heat treatment and cooling was 749 minutes.

[0145]

[0146] Comparative Example 2: Preparation of Solid Electrolyte

[0147] A sulfide-based solid electrolyte was manufactured using the same manufacturing method as Comparative Example 1, except that the above-mentioned intermediate product was heated to 280°C at a heating rate of 6.6°C per second in an RTA device without going through a particle size control process and was subjected to overshooting heat treatment by maintaining the product at 280°C for 10 seconds in an inert atmosphere. The total time required for the heat treatment in the RTA device was 49 seconds, and the time required for cooling after heating was 60 seconds. In other words, the total time required for the heat treatment and cooling was 109 seconds.

[0148] After heat treatment, a sulfide-based solid electrolyte was prepared by adding 10 L of toluene to prepare a slurry, which was then pulverized by operating a ball mill device at 300 rpm for 12 hours. After pulverization, the solvent was removed by vacuum drying at 80°C, and a sulfide-based solid electrolyte with controlled particle size was obtained.

[0149]

[0150] Comparative Example 3: Preparation of Solid Electrolyte

[0151] A sulfide-based solid electrolyte was manufactured using the same manufacturing method as Example 1, except that the RTA equipment was heated at a heating rate of 6.6°C per second and maintained in an inert atmosphere at a temperature of 310°C for 10 seconds.

[0152]

[0153] Comparative Example 4: Preparation of Solid Electrolyte

[0154] A sulfide-based solid electrolyte was manufactured using the same manufacturing method as Example 6, except that the RTA equipment was heated at a heating rate of 6.6°C per second and maintained in an inert atmosphere at a temperature of 310°C for 10 seconds.

[0155]

[0156] Evaluation Example 1: DSC

[0157] A total of 40 g of precursor mixed with lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), lithium bromide (LiBr), and lithium iodide (LiI) in a ratio of 6:2:1:1 was weighed and subjected to high-energy milling (mechanical milling) for 40 hours using a Fritsch P5 model along with 500 g of 3 mm zirconia balls and 250 cc of heptane, a non-polar solvent.

[0158] The intermediate product manufactured after milling was obtained by vacuum drying at 80°C, and then the 3 mm zirconia balls were removed through a sieving machine to prepare the intermediate product.

[0159] To confirm the glass transition temperature (Tg) and crystallization temperature (Tc) of the prepared intermediate product, DSC was measured and analyzed. The DSC results of the intermediate product are shown in Fig. 4.

[0160] Referring to Fig. 4, it can be confirmed that the glass transition temperature (Tg) of the dried intermediate product is about 170°C, the primary crystallization temperature (Tc1) is about 180°C, and the secondary crystallization temperature (Tc2) is about 250°C.

[0161]

[0162] Evaluation Example 2: XRD

[0163] To confirm the crystallinity of the sulfide-based solid electrolytes manufactured according to Examples 1 to 7 and Comparative Examples 1 to 4, XRD was measured at an angle of 10 to 40 degrees, and a dome holder made of PEEK material was used to measure the reactivity in the air. The XRD results are shown in Figs. 5 to 8.

[0164]

[0165] Figure 5 is a graph showing the XRD results of an intermediate product according to Evaluation Example 1 and a sulfide-based solid electrolyte manufactured according to Comparative Examples 1 and 2.

[0166] Referring to Fig. 5, the intermediate product according to Evaluation Example 1 and the sulfide-based solid electrolyte manufactured according to Comparative Example 1 do not have peaks observed in the XRD results. This is because the first crystallization temperature (T c1 ) It can be confirmed that a glassy crystalline solid electrolyte was not formed because nucleation did not occur due to heat treatment for an insufficient time at a temperature lower than 180℃. The sulfide-based solid electrolyte manufactured according to Comparative Example 2 was manufactured within the heat treatment temperature (T) range, but since particle size control was performed at a stage after the heat treatment, the high ionic conductivity phase was hardly expressed, and thus no peak was observed in the XRD results.

[0167] Figure 6 is a graph showing the XRD results of sulfide-based solid electrolytes manufactured according to Examples 1 to 5.

[0168] Referring to FIG. 6, it can be confirmed that the sulfide-based solid electrolytes manufactured according to Examples 1 to 5 exhibit high ionic conductivity phases at around 20°C, 23.5°C, 28.6°C, and 29.3°C based on XRD results, while the most stable phase, lithium tetrasulfide (Li3PS4), is not formed. This is because strong energy is briefly irradiated through overshooting, a method for promoting nucleation, to instantaneously generate crystal nuclei due to the high temperature of 280°C, and the nuclei are maintained from growing through a short heat treatment time and cooling time. In addition, it can be confirmed that in Examples 1 to 5, by continuously performing a particle size control process by omitting the drying step after the first milling, an ultra-high ionic conductivity phase is expressed even at a relatively low temperature range of 220°C to 300°C. In the above temperature range, as the temperature increases, the degree to which high ionic conductivity is expressed increases, and it can be confirmed that this is because the ratio of amorphous decreases as the amorphous becomes crystallized.

[0169] Figure 7 is a graph showing the XRD results of a sulfide-based solid electrolyte manufactured according to Example 5 and Comparative Example 3.

[0170] Referring to Fig. 7, it can be confirmed that Comparative Example 3 was produced at around 17 degrees, around 21 degrees, and around 27.5 degrees based on the XRD results. Comparative Example 3 continuously performed the particle size control process by omitting the drying step after the first milling as in Example 5, but the heat treatment temperature (T) (T g + 50℃ ≤ T ≤ T g The crystallinity can be increased by heat treatment at 310℃, which exceeds +130℃, but it can be confirmed that the most stable phase, lithium tetrasulfide (Li3PS4), is generated by nucleus growth along with nucleus generation.

[0171] Figure 8 is a graph showing the XRD results of sulfide-based solid electrolytes manufactured according to Examples 6 and 7 and Comparative Example 4.

[0172] Referring to Fig. 8, Examples 6 and 7 and Comparative Example 4 all have in common that they went through a drying step after the first milling and then performed particle size control through the second milling. However, the sulfide-based solid electrolytes manufactured according to Examples 6 and 7 had a heat treatment temperature (T) (T g + 50℃ ≤ T ≤ T g Even when heat-treated at relatively low temperatures of 220°C and 240°C within the range of + 130°C, it can be confirmed that high ionic conductivity phases are observed around 20°C, 23.5°C, 28.6°C, and 29.3°C in the XRD results, while the most stable phase, lithium tetrasulfide (Li3PS4), is not generated. In contrast, Comparative Example 4 is heat-treated at 310°C, which exceeds the heat-treatment temperature (T) range, and the degree of crystallinity may increase, but it can be confirmed that the most stable phase, lithium tetrasulfide (Li3PS4), is generated by nucleus growth along with nucleus generation.

[0173] Whether a high ionic conductivity phase was created in Examples 1 to 8 and Comparative Examples 1 to 3 is shown in Table 1 below.

[0174]

[0175] Evaluation Example 3

[0176] After confirming the crystallinity of the sulfide-based solid electrolytes manufactured according to Examples 1 to 7 and Comparative Examples 1 to 3, they were pressurized at 6.6 tons in a mold-shaped pressure cell with a diameter of 13 mm, and then maintained at a temperature of 30°C for more than 3 hours in an oven, after which the lithium ion conductivity was measured, and the thickness and weight were measured to determine the compressed density. The ion conductivity and compressed density are shown in Table 1 below.

[0177]

[0178] High ionic conductivity phase presence / absence Ionic conductivity (mS / cm) Compressed density (g / cc) Example 102.862.01 Example 203.741.99 Example 305.211.98 Example 406.291.93 Example 506.181.89 Example 602.951.86 Example 702.011.98 Comparative Example 1X--Comparative Example 201.411.89 Comparative Example 3X--Comparative Example 4X--

[0179]

[0180] According to Table 1 above, the sulfide-based solid electrolytes manufactured according to Examples 1 to 7 include a particle size control process prior to heat treatment during the manufacturing process, so that even when manufactured at a relatively low heat treatment temperature of 220°C to 300°C, the most stable phase, lithium tetrasulfide (Li3PS4), is not generated, and nucleation is induced to develop a high ionic conductivity phase, thereby improving ionic conductivity, and the heat treatment time is shortened to 10 to 20 seconds, confirming that they are structurally stable.

[0181] In particular, it can be confirmed that the sulfide-based solid electrolytes manufactured according to Examples 1 to 5 can minimize process variables and have greatly improved ionic conductivity by optimizing process steps including a continuous particle size control process before heat treatment.

[0182] In addition, the sulfide-based solid electrolytes manufactured according to Examples 1 to 7 have high compression densities, which can be interpreted as meaning that a large amount of glass (amorphous) structure remains. Since glass (amorphous) has excellent formability, the higher the compression density in the same material, the better the formability. Therefore, the sulfide-based solid electrolyte manufactured according to one embodiment of the present invention can be advantageously applied to all-solid-state batteries.

[0183] In contrast, the sulfide-based solid electrolyte manufactured according to Comparative Example 1 was heat-treated below the heat treatment temperature range of the present invention without particle size control, and thus the high ionic conductivity phase was not developed. It was confirmed that the sulfide-based solid electrolyte manufactured according to Comparative Example 2 exhibited a sharp decrease in ionic conductivity as the particle size control was performed at a stage after the heat treatment, with little development of the high ionic conductivity phase. In Comparative Examples 3 and 4, the heat treatment temperature was 310°C, exceeding the heat treatment temperature (T) of the present invention. Although the degree of crystallinity may increase, it was confirmed that the ionic conductivity decreased as the most stable phase, lithium tetrasulfide (Li3PS4), was generated by nucleation and nucleus growth.

Claims

1. A step (S1) of preparing a precursor solution by introducing a precursor containing alkali metal sulfide, phosphorus sulfide, and halogen compound into a solvent; Step (S2) of producing an intermediate product by first milling the precursor solution; Step (S3) of adjusting the particle size of the intermediate product by adding a dispersant after the above step (S2) and performing a second milling; A step (S4) of drying the intermediate product whose particle size has been adjusted after the above step (S3); and A step (S5) of heat-treating the above-described dried intermediate product; The above dispersant is an aliphatic compound, A method for producing a sulfide-based solid electrolyte, wherein the mass ratio of the solvent and the dispersant is 75:1 to 150:

1.

2. In paragraph 1, A method for producing a sulfide-based solid electrolyte, wherein the alkali metal sulfide comprises lithium sulfide (Li2S), sodium sulfide (Na2S), or potassium sulfide (K2S).

3. In paragraph 1, A method for producing a sulfide-based solid electrolyte, wherein the above halogen compound comprises at least one substance selected from the group consisting of lithium bromide (LiBr), lithium chloride (LiCl), lithium iodide (LiI), and lithium fluoride (LiF).

4. In paragraph 1, A method for producing a sulfide-based solid electrolyte, wherein the solvent is at least one selected from the group consisting of heptane, hexane, cyclohexane, and toluene.

5. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte, wherein each of the above steps (S2) and (S3) can be performed for 5 to 40 hours.

6. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte, wherein each of the above steps (S2) and (S3) can be performed using balls in a planetary ball mill method, an attrition mill method, a SPEX mill method, a ball mill method, or a bead mill method.

7. In paragraph 6, A method for manufacturing a sulfide-based solid electrolyte, wherein each of the above steps (S2) and (S3) is milled by adjusting the mass ratio of the precursor and the ball to 1:10 to 1:

20.

8. In paragraph 6, The diameter of the ball used in the above step (S2) is 0.5 mm to 5 mm, A method for manufacturing a sulfide-based solid electrolyte, wherein the diameter of the ball used in the above step (S3) is 0.1 mm to 1 mm.

9. In paragraph 1, A method for producing a sulfide-based solid electrolyte, wherein the dispersant is at least one selected from the group consisting of dibutyl ether (DBE), diglyme, tetraglyme, dimethoxyethane (DME), and combinations thereof.

10. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte having an average particle size controlled by the above step (S3) of 0.1 ㎛ to 5 ㎛.

11. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte, wherein the step (S4) of drying the above-mentioned particle-sized intermediate product is performed at 60°C to 100°C.

12. In paragraph 1, The step (S5) of heat-treating the above-mentioned dried intermediate product is a method for manufacturing a sulfide-based solid electrolyte, which comprises heating the product from room temperature to a heat treatment temperature according to the following formula 1 and then holding the temperature for 10 to 20 seconds: [Formula 1] T g + 50℃ ≤ T ≤ T g + 130℃ The above T g is the glass transition temperature of the above dried intermediate product.

13. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte, wherein the step (S5) of heat-treating the above-mentioned dried intermediate product is performed for 30 to 50 seconds.

14. In paragraph 1, Further comprising a step (S2′) of drying the intermediate product before the step (S3); A method for manufacturing a sulfide-based solid electrolyte, wherein each of the above steps (S2′) and (S4) is performed at 60°C to 100°C.

15. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte, further comprising a step (S6) of cooling the product obtained through the above heat treatment, wherein the cooling is performed within 1 minute.

16. In paragraph 1, The above sulfide-based solid electrolyte is a method for manufacturing a sulfide-based solid electrolyte having a glass-ceramic structure.

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