Method for producing sulfide-based solid electrolyte

Abstract

A method for producing a sulfide-based solid electrolyte having a desired particle size by wet pulverization is disclosed. The method includes: preparing a sulfide-based solid electrolyte material; and wet-pulverizing the sulfide-based solid electrolyte material to obtain a fine particle size. The wet pulverization uses an organic solvent as a dispersant and a ketone solvent as a dispersion stabilizer.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a sulfide-based solid electrolyte, and more particularly to a method for producing a sulfide-based solid electrolyte in which the particle size is controlled by atomizing the assembly materials by wet grinding. [Background technology]

[0002] An all-solid-state battery is one in which the electrolyte, one of the components of a battery, is replaced from the conventional liquid to a solid, using a solid electrolyte instead of the electrolyte solution and separator required in conventional lithium-ion batteries. Therefore, compared to conventional batteries that use liquid electrolytes, all-solid-state batteries are poised to attract attention as next-generation secondary batteries because they are free from the risk of battery explosion or fire, have a simplified manufacturing process, and can achieve high energy density.

[0003] Among inorganic solid-state electrolytes (SSEs), sulfide-based solid electrolytes are gaining attention as solid-state electrolytes (SSEs) for all-solid-state batteries. However, most sulfide-based solid electrolytes require prolonged, high-energy milling of raw materials such as Li2S, P2S5, and LiCl, followed by a sintering process to increase crystallinity and improve ionic conductivity. This sintering process increases the particle size of the solid electrolyte. Therefore, the synthesized materials must be appropriately micronized according to the cell application location of the solid electrolyte. However, sulfide-based solid electrolytes are soft materials that are difficult to micronize. Furthermore, when micronizing solid electrolytes by mechanical milling, they can adhere to the milling media or re-agglomerate, reducing the recovery rate of the solid electrolyte. In particular, wet milling during the micronization process can leave impurities, such as the solvent used as a dispersant, remaining, reducing the ionic conductivity of the solid electrolyte. Summary of the Invention [Problem to be solved by the invention]

[0004] In order to solve the above-mentioned problems of the prior art, an object of the present invention is to provide a method for producing a sulfide-based solid electrolyte having a desired particle size by wet pulverization.

[0005] Another object of the present invention is to provide a method for producing a sulfide-based solid electrolyte that can improve the recovery rate of the solid electrolyte by suppressing the phenomenon of the solid electrolyte adhering to the grinding medium or re-agglomeration during wet grinding and facilitating disintegration.

[0006] Another object of the present invention is to provide a method for producing a sulfide-based solid electrolyte using a wet grinding process that suppresses a decrease in ionic conductivity. [Means for solving the problem]

[0007] In order to achieve the above technical object, the present invention provides a method for producing a sulfide-based solid electrolyte material, which is a compound containing Li, A (A is at least one of P, Si, Ge, Al, B, and Sn), and S;

[0008] and wet-pulverizing the sulfide-based solid electrolyte material to form a fine particle, wherein the wet-pulverization uses an organic solvent as a dispersant and a ketone solvent as a dispersion stabilizer.

[0009] In the present invention, the dispersion stabilizer may be contained in an amount of 0.01 to 10 parts by volume relative to 100 parts by volume of the dispersion.

[0010] In the present invention, the dispersion stabilizer may be contained in an amount of 0.1 to 2 parts by volume relative to 100 parts by volume of the dispersion.

[0011] In the present invention, the ketone solvent preferably has two hydrocarbon groups or hydrocarbon derivatives linked to a carbonyl group (C=O), and at least one of the two hydrocarbon groups or hydrocarbon derivatives has 5 or less carbon atoms. In particular, the ketone solvent may include at least one of methyl isobutyl ketone, acetone, butyl methyl ketone, diethyl ketone, diisobutyl ketone, methyl ethyl ketone, methyl pentyl ketone, and methyl propyl ketone.

[0012] In the present invention, the organic solvent may include at least one of a hydrocarbon-based non-polar solvent and an aromatic compound.

[0013] The present invention may further include a step of removing the dispersant and dispersion stabilizer and recovering the powder after the pulverization step, and the weight of the recovered powder may be 80% or more of the weight of the added powder. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a sulfide-based solid electrolyte of a desired particle size by wet pulverization. Furthermore, according to the present invention, the phenomenon of the solid electrolyte adhering to the pulverization medium or re-agglomeration is suppressed during wet pulverization, and pulverization is facilitated, thereby improving the recovery rate of the solid electrolyte. Furthermore, according to the present invention, it is possible to produce a sulfide-based solid electrolyte by applying a wet pulverization process that suppresses a decrease in ionic conductivity. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a graph showing the results of particle size analysis of Examples 1 to 4 and Comparative Examples 1 to 4, arranged according to the amount of balls used in the pulverization step.

[0016] [Figure 2] 1 is a graph showing the recovery rate results of Examples 1 to 4 and Comparative Examples 1 to 4, arranged according to the amount of balls used in the crushing step.

[0017] [Figure 3] 1 is a graph summarizing the results of particle size analysis of the powder test pieces of Examples 5 to 11 and Comparative Example 5.

[0018] [Figure 4] 1 is a graph plotting the recovery rate measurement results of Examples 5 to 11 and Comparative Example 5.

[0019] [Figure 5] 1 is a graph comparing the ionic conductivity measurement results and particle size of Examples 5 to 11 and Comparative Example 5.

[0020] [Figure 6] 1 is a graph showing the results of calculating the ratio of ionic conductivity to volume in an example of the present invention.

[0021] [Figure 7] 1 is a graph showing the results of XRD analysis of a powder test piece manufactured in an example of the present invention.

[0022] [Figure 8] 1 is a graph summarizing the results of particle size analysis of powder test pieces obtained in further examples of the present invention.

[0023] [Figure 9] 10 is a graph summarizing the results of measuring the recovery rate of powder test pieces obtained in further examples of the present invention.

[0024] [Figure 10] 1 is a graph showing a comparison of the ionic conductivity measurement results and particle size for Example 7, Examples 12 to 18, and Comparative Example 5.

[0025] [Figure 11] 10 is a graph showing the calculated ionic conductivity / volume ratio of a powder test piece obtained in a further example of the present invention.

[0026] [Figure 12] 1 is a graph showing the results of electron conductivity analysis of an example of the present invention and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0027] The embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, so it should be understood that various equivalents and modifications may exist at the time of filing this application. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0028] In the method for producing a solid electrolyte of the present invention, the sulfide-based solid electrolyte material may be a compound containing Li, A, and S, where A may contain at least one of P, Si, Ge, Al, B, and Sn. In the sulfide-based solid electrolyte compound, S may be partially substituted with a halogen element (F, Cl, Br, I), oxygen (O), nitrogen (N), or the like.

[0029]

[0030] The method for producing a solid electrolyte according to the present invention may be applied to sulfide-based solid electrolytes having, for example, Li2S-P2S5 glass, Li-PS glass ceramic, argyrodite, Thio-LISICON, and LGPS crystal structures.

[0031] The method for producing a solid electrolyte according to the present invention is particularly 7-x PS 6-x X x (wherein X is at least one element selected from the group consisting of F, Cl, Br, I, O, and N, and 0≦x≦2).

[0032] Each step of the production method of the present invention will be described in detail below.

[0033]

[0034] A. Synthesis of solid electrolyte

[0035] A sulfide-based solid electrolyte having a desired composition can be synthesized by a known method, for example, a solid-phase synthesis method in which a lithium source, a sulfur source, a phosphorus source, and a halogen source are pulverized and mixed, or a liquid-phase synthesis method in which each source is dissolved in a solvent.

[0036] After synthesizing a solid electrolyte of the desired composition, a calcination process can be performed to increase crystallinity and improve ionic conductivity. For example, to synthesize a Li6PS5Cl compound, calcination can be performed at a temperature of 400 to 600°C for 1 to 12 hours in an inert atmosphere such as Ar or N2.

[0037] The above synthesis methods are merely exemplary, and it goes without saying that other powders synthesized by any method may be used in the solid electrolyte synthesis process of the present invention.

[0038]

[0039] B. Solid electrolyte particle size control

[0040] To control the particle size of the solid electrolyte, a wet-milling process is used, which may be carried out using a ball mill, a bead mill, a planetary ball mill, or the like, with a dispersing wheel.

[0041] In the wet-milling process of the present invention, an organic solvent may be used as a dispersant, preferably a hydrocarbon-based non-polar solvent or an aromatic compound. For example, hydrocarbon-based non-polar solvents such as hexane, heptane, octane, nonane, decane, undecane, dodecane, and mixtures thereof may be used, and aromatic compounds such as benzene, ethylbenzene, durene, diethylbenzene, styrene, xylene, and toluene may be used.

[0042] In the wet grinding step of the present invention, a dispersion stabilizer is used to improve grinding efficiency. Ketone solvents are preferably used as the dispersion stabilizer. In the present invention, the ketone compound serving as the dispersion stabilizer has two hydrocarbon groups or hydrocarbon derivatives linked to a carbonyl group (C=O). For easy removal of the dispersion stabilizer, it is preferred that at least one of the two hydrocarbon groups or hydrocarbon derivatives has 10 or less carbon atoms, particularly 5 or less. For example, one or a mixture of compounds selected from the group consisting of methyl isobutyl ketone, acetone, butyl methyl ketone, diethyl ketone, diisobutyl ketone, methyl ethyl ketone, methyl pentyl ketone, methyl propyl ketone, dipropyl ketone, ethyl pentyl ketone, ethyl butyl ketone, ethyl propyl ketone, and ethyl isopropyl ketone may be used.

[0043] In the present invention, the ketones used as dispersion stabilizers suppress the aggregation of solid electrolytes during the pulverization process, enabling the production of fine-grained powders. Furthermore, the ketones used as dispersion stabilizers improve the pulverization yield by suppressing adhesion of solid electrolyte powders to pulverization media such as balls. Furthermore, the dispersion stabilizers used in the micronization process of the present invention increase the pulverization efficiency, thereby suppressing the decrease in ionic conductivity that occurs during the micronization process.

[0044] In the present invention, the dispersion stabilizer is preferably present in an amount of 0.01 to 10 parts by volume, and more preferably 0.1 to 2 parts by volume, per 100 parts by volume of dispersion powder. Within this concentration range, the finely divided powder exhibits a higher average particle size. However, if the dispersion stabilizer exceeds 10 parts by volume, the powder will exhibit a particle size distribution similar to that observed in the absence of the dispersion stabilizer. Therefore, from the viewpoint of particle size distribution, the dispersion stabilizer is preferably present in an amount of 10 parts by volume or less. Furthermore, from the viewpoint of ionic conductivity, the dispersion stabilizer is preferably present in an amount of 0.01 to 10 parts by volume, and particularly 0.1 to 2 parts by volume.

[0045] Generally, when a solid electrolyte is atomized, its ionic conductivity decreases. The reasons for this decrease in ionic conductivity are i) the increase in the number of interfaces between particles due to the decrease in particle size, which increases the overall resistance, and ii) the decrease in the crystallinity of the solid electrolyte during the pulverization process. Therefore, it is difficult to directly compare the ionic conductivities of solid electrolytes with different particle sizes. In the present invention, to compare the ionic conductivities of solid electrolytes with different particle sizes, the ratio of ionic conductivity to particle volume (R) is defined as follows:

[0046] R = (ionic conductivity) / (particle volume)

[0047] The volume of the particles was calculated using the following formula, assuming that the particles whose particle size was measured were spherical.

[0048] (particle volume)=4 / 3πr 3 , r=(granularity,D50) / 2

[0049] Based on this, assuming that the particles are of the same size, the ratio of ionic conductivity to particle volume was calculated and compared.

[0050]

[0051] In the present invention, a specific atomization process using the aforementioned dispersion medium and dispersion stabilizer may be appropriately designed. As an example, the atomization process may include a coarse pulverization process and a fine pulverization process. In the case of a ball mill or a planetary mill, the pulverization efficiency can be improved by using balls with a large diameter in the coarse pulverization process and balls with a small diameter in the fine pulverization process.

[0052] After the pulverization process, the dispersion medium and the dispersion stabilizer may be removed by various methods such as filtration, precipitation, or vacuum drying.

[0053] In the present invention, the particle size of the sulfide-based solid electrolyte powder obtained through the above process may have the following characteristics.

[0054] 2.5 < D <![CDATA[ 50 ]] (μm) < 3.5,

[0055] 0.9 < SPAN < 1.35 (where the particle size distribution span (SPAN) = (D <![CDATA[ 90 ]] - D <![CDATA[ 10 ]] ) / D <![CDATA[ 50 ]] )

[0056] Also, in the present invention, the recovery rate, which means the ratio of the recovered powder weight to the input powder weight, may be 80% or more, 85% or more, or 90% or more.

[0057] On the other hand, the ionic conductivity of the sulfide-based solid electrolyte powder of the present invention is preferably 1.0 mS / cm or more, 1.1 mS / cm or more, or 1.2 mS / cm or more. In the present invention, it is possible to manufacture a sulfide-based solid electrolyte powder having an ionic conductivity of up to 1.4 mS / cm.

[0058] In the present invention, the ratio (R) of ionic conductivity to particle volume may be 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, or 0.1 or more. However, it should be noted that in the present invention, the ratio of ionic conductivity to particle volume is a relative value that can vary according to the type of solid electrolyte, particle size, etc.

[0059]

Example

[0060] Hereinafter, the present invention will be described in detail using examples.

[0061] <Synthesis Example of Li6PS5Cl>

[0062] Li2S, P2S5, and LiCl were weighed as starting materials and pulverized and mixed using a planetary ball mill. Specifically, in a PM400 planetary mill manufactured by Retsch, using Φ15 mm balls, dry milling was performed at a rotational speed of 200 to 350 rpm for 2 to 12 Hr (PM400).

[0063] Subsequently, the milled starting materials were heat-treated and fired at a temperature of 550 °C for 6 hours in an inert atmosphere to synthesize Li6PS5Cl.

[0064]

[0065] <Example 1>

[0066] 100 g of Li6PS5Cl synthesized in the experimental example was placed in a 500 ml jar, together with 400 g of Φ10 mm balls, 250 ml of decane, and 0.25 ml of methyl isobutyl ketone, and first coarsely pulverized using a planetary ball mill.

[0067] The coarsely ground Li6PS5Cl powder was then collected and finely ground to adjust the particle size. 100 g of 3 mm diameter balls, 10 g of the coarsely ground Li6PS5Cl, 250 ml of decane, and 12.5 ml of methyl isobutyl ketone were weighed and placed in a 500 ml jar, and the mixture was milled in a planetary ball mill.

[0068] After grinding was completed, the balls were separated and filtered, and the solids were collected and dried in vacuum at 80-120°C for 3-12 hours to produce powder test pieces. The weight of Li6PS5Cl before grinding was taken as the input amount, and the content of the powder remaining after vacuum drying was taken as the recovered amount. The recovery rate was calculated using the following formula:

[0069] <Formula 1>

[0070] (Recovery rate) = (recovery amount) / (input amount) * 100

[0071]

[0072] <Examples 2 to 4>

[0073] In Examples 2 to 4, solid electrolyte powders were produced under the same conditions as in Example 1, except that the amounts of balls used as dispersion media in the fine pulverization step were 200 g, 300 g, and 400 g, respectively.

[0074]

[0075] <Comparative Examples 1 to 4>

[0076] In Comparative Examples 1 to 4, solid electrolyte powders were produced under the same conditions as in Examples 1 to 4, except that no dispersion stabilizer was added in the pulverization step. That is, in Comparative Examples 1 to 4, the amount of balls used as the dispersion medium in the pulverization step was 100 g, 200 g, 300 g, and 400 g, respectively, 250 ml of decane was used as the dispersion medium, and no dispersion stabilizer was added.

[0077]

[0078] <Example 5>

[0079] 100 g of Φ3 mm balls, 10 g of coarsely ground Li6PS5Cl, 150 ml of decane, and 0.15 ml of methyl isobutyl ketone were weighed and placed in a 500 ml jar, and then a planetary ball mill was used.

[0080] After the grinding was completed, the balls were separated and filtered, and the solid matter was recovered and dried in vacuum at a temperature of 80 to 120°C for 3 to 12 hours to prepare powder test pieces.

[0081]

[0082] <Examples 6 to 11>

[0083] Solid electrolyte powder test pieces were produced in the same manner as in Example 5, except that the content of the dispersion stabilizer was varied.

[0084] Specifically, the Li6PS5Cl powder was pulverized at different concentrations of the dispersion stabilizer, 0.5, 1.0, 2.0, 5.0, 7.5, and 10 parts by volume, based on 100 parts by volume of the dispersion mass, to produce powder test pieces of Examples 6 to 11.

[0085]

[0086] <Comparative Example 5>

[0087] A powder test piece of Comparative Example 5 was produced in the same manner as in Example 5, except that no dispersion stabilizer was used.

[0088] In Examples 5 to 11 and Comparative Example 5, the concentrations of the dispersion stabilizers, which represent the parts by volume of the dispersion stabilizer relative to 100 parts by volume of the dispersion liquid, are as shown in the table below.

[0089] [Table 1]

[0090] <Examples 12 to 18> The concentration of the dispersion stabilizer was fixed at 1 part by volume, and the type of dispersion stabilizer was varied, and powder test pieces were prepared under the same process conditions as in Example 7. The dispersion stabilizers used in each example are listed in Table 2 below.

[0091] [Table 2]

[0092] <Powder test piece evaluation> A. Particle size distribution

[0093] The powder specimen was dispersed in toluene and placed in a device with a flow rate of 55%, and treated with 40W ultrasonic waves for 120 seconds five times. Then, the particle size distribution was measured using a Microtrac S3500.

[0094] The particle size distribution span was calculated by the following formula:

[0095] Particle size distribution span (SPAN) = (D 90 -D 10 ) / D 50

[0096]

[0097] B.EIS

[0098] A 100 mg powder specimen was placed in a 10 mm diameter mold and pressed at 310 MPa. An indium (In) electrode was attached to each mold to prepare a cell. Impedance measurements were performed using a potentiostat / galvanostat (VSP-300). The frequency range was 0.1 Hz to 1 MHz, and the amplitude voltage was 100 mV.

[0099] The resistance value was determined from the arc of the Nyquist plot of the impedance measurement results, and the ionic conductivity was calculated taking into account the area and thickness of the test piece.

[0100]

[0101] C. Ratio of ionic conductivity to particle volume (R)

[0102] D in μm at which the particle size distribution was measured 50 The value was taken as the representative value for the powder test piece, and the volume of the spherical particle was calculated assuming a spherical particle with this value as the diameter. Next, the measured ionic conductivity value of the powder test piece in mS / cm units was converted to μm 3 The ratio R (unitless) was defined by dividing by the volume of a unit spherical particle.

[0103]

[0104] D. Electronic conductivity

[0105] A 100 mg powder specimen was placed in a 10 mm diameter mold and pressed at 310 MPa. SUS electrodes were then placed on each specimen to prepare a cell. A voltage of 1 V was applied using a potentiostat / galvanostat (VSP-300), and the current was measured after 1 hour. The electrical conductivity was calculated based on the measured current, taking into account the area and thickness of the specimen.

[0106]

[0107] E.XRD

[0108] XRD spectra were measured using a Malvern Panalytical Aeris instrument (Cu kα, λ=1.5406 Å) at a voltage of 40 kV and a current of 15 mA.

[0109]

[0110] Figures 1 and 2 are graphs summarizing the size of crushed particles and the recovery rate of powder depending on the amount of balls used as a dispersion medium.

[0111] Referring to Figure 1, when a dispersion stabilizer is used, the particle size decreases depending on the amount of balls added, making it easy to control the particle size. However, when a dispersion stabilizer is not used, the particle size does not decrease beyond a certain level even when the amount of balls is increased, making it difficult to control the particle size.

[0112] Referring to Figure 2, when a dispersion stabilizer is used, the recovery rate remains high even when the amount of added balls increases, but when a dispersion stabilizer is not used, the amount of powder that adheres to the balls or re-agglomerates increases, resulting in a sudden decrease in the recovery rate.

[0113] The particle sizes and recovery rates of Examples 1 to 4 and Comparative Examples 1 to 4 are summarized in Table 3 below.

[0114] [Table 3]

[0115] Figure 3 is a graph summarizing the results of particle size analysis of the powder test pieces of Examples 5 to 11 and Comparative Example 5. Referring to Figure 3, it can be seen that in Examples 5 to 11, in which methyl isobutyl ketone was used as a dispersion stabilizer, the average particle size (D50) was significantly reduced compared to Comparative Example 5, in which no dispersion stabilizer was used. The results of particle size analysis for each Example and Comparative Example are shown in Table 4 below.

[0116] [Table 4]

[0117] Figure 4 is a graph showing the measurement results of the recovery rate. Referring to Figure 4, it can be seen that the Example exhibits a higher recovery rate than Comparative Example 5. Table 5 below summarizes the measurement results of the recovery rate for each dispersion stabilizer content.

[0118] [Table 5]

[0119] FIG. 5 is a graph showing the results of ionic conductivity measurements. Referring to FIG. 5, the ionic conductivity of the Examples generally exhibits lower values ​​than the Comparative Examples. This is believed to be due to the fact that the Comparative Examples did not use a dispersion stabilizer and were unable to adjust the particle size to the desired level, resulting in the powder specimens of the Comparative Examples having smaller particle sizes than the powder specimens of the Examples, resulting in increased interparticle interfaces during compaction. Therefore, a standardized criterion was found to be necessary to compare Examples and Comparative Examples for the same particle size level, and the present invention introduced a criterion known as the ratio of ionic conductivity to particle volume (R). FIG. 6 is a graph showing the ratio of ionic conductivity to particle volume for Examples and Comparative Examples.

[0120] 6, the ratio of ionic conductivity to particle volume of the Example is higher than that of the Comparative Example. From this, it can be predicted that the ionic conductivity of the powder test piece of the Example will be higher than that of the powder test piece of the Comparative Example, which is assumed to be the same size.

[0121] FIG. 7 is a graph showing the results of XRD analysis of a powder test piece synthesized in an experimental example before particle size control and a powder test piece of Example 7 after wet milling.

[0122] Referring to FIG. 7, when compared with the Li6PS5Cl reference peak, it can be seen that crystalline phase Li6PS5Cl is synthesized, and that the Li6PS5Cl phase is maintained even after pulverization.

[0123] 8 is a graph summarizing the results of particle size analysis of the powder test pieces of Examples 12 to 18. For comparison, particle size data of Example 7 and Comparative Example 5 are also shown.

[0124] Referring to FIG. 8, it can be seen that in Examples 12 to 18, in which a ketone dispersion stabilizer was used, the average particle size (D50) was significantly reduced compared to Comparative Example 5, in which no dispersion stabilizer was used.

[0125] The results of particle size analysis for each of the Examples and Comparative Examples are shown in Table 6 below.

[0126] [Table 6]

[0127] Fig. 9 is a graph summarizing the measurement results of the recovery rates of the powder test pieces of Examples 12 to 18. For comparison, the recovery rates of Example 7 and Comparative Example 5 are also shown. Referring to Fig. 9, it can be seen that the Examples exhibit higher recovery rates than Comparative Example 5. Table 7 below summarizes the measurement results of the recovery rates by type of dispersion stabilizer.

[0128] [Table 7]

[0129] 10 and 11 are graphs showing the measurement results of the ionic conductivity and the ratio of ionic conductivity to particle volume of the powder test pieces of Examples 12 to 18. For comparison, Example 7 and Comparative Example 5 are also shown. Referring to FIG. 11, it can be seen that the ratio of ionic conductivity to particle volume of the Examples is higher than that of the Comparative Example. FIG. 12 is a graph showing the results of measuring the electronic conductivity of the Examples and Comparative Example.

[0130] 12, it can be seen that there is no significant difference between the electronic conductivities of the Examples and Comparative Examples. Therefore, there is no change in electronic conductivity depending on the content and type of dispersion stabilizer, which means that there is almost no residual dispersion stabilizer.

[0131]

[0132] Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will recognize that various modifications can be made to the above-described embodiments without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the following claims and equivalents to these claims. [Industrial Applicability]

[0133] The present invention is applicable to solid electrolytes in lithium secondary batteries.

Claims

1. A step of preparing a sulfide-based solid electrolyte material that is a compound containing Li, A (A includes at least one of P, Si, Ge, Al, B, and Sn), and S; and a micronization step of wet-pulverizing the sulfide-based solid electrolyte material, The method for producing a sulfide-based solid electrolyte uses an organic solvent as a dispersant used in the wet grinding and a ketone solvent as a dispersion stabilizer.

2. 2. The method for producing a sulfide-based solid electrolyte according to claim 1, wherein the dispersion stabilizer is contained in an amount of 0.01 to 10 parts by volume per 100 parts by volume of the dispersion liquid.

3. 3. The method for producing a sulfide-based solid electrolyte according to claim 2, wherein the dispersion stabilizer is contained in an amount of 0.1 to 2 parts by volume per 100 parts by volume of the dispersion liquid.

4. 2. The method for producing a sulfide-based solid electrolyte according to claim 1, wherein the ketone solvent has two hydrocarbon groups or hydrocarbon derivatives linked to a carbonyl group (C═O), and at least one of the two hydrocarbon groups or hydrocarbon derivatives has five or less carbon atoms.

5. 5. The method for producing a sulfide-based solid electrolyte according to claim 4, wherein the ketone solvent includes at least one of methyl isobutyl ketone, acetone, butyl methyl ketone, diethyl ketone, diisobutyl ketone, methyl ethyl ketone, methyl pentyl ketone, and methyl propyl ketone.

6. 2. The method for producing a sulfide-based solid electrolyte according to claim 1, wherein the organic solvent includes at least one of a hydrocarbon-based non-polar solvent and an aromatic compound.

7. After the atomization step, removing the dispersant and dispersion stabilizer to recover the powder; 2. The method for producing a sulfide-based solid electrolyte according to claim 1, wherein the weight of the recovered powder is 80% or more of the weight of the charged powder.

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