Preparation method of sulfide solid electrolyte

Abstract

The present invention relates to the field of solid electrolyte technology, and in particular to a method for preparing a sulfide solid electrolyte. The method for preparing a sulfide solid electrolyte comprises the following steps: a sulfide solid electrolyte precursor is subjected to at least two electromagnetic wave treatments under a protective atmosphere; the preparation of the sulfide solid electrolyte precursor comprises: mixing and ball milling the sulfide solid electrolyte raw materials. The method for preparing a sulfide solid electrolyte of the present invention is different from the traditional melt quenching process. It is treated at least twice with electromagnetic waves, does not need to be heated to a high temperature, and can simply and quickly obtain a uniform, highly conductive sulfide solid electrolyte through the material's absorption characteristics of electromagnetic waves of different frequencies.

Description

Technical Field

[0001] The present invention relates to the technical field of solid electrolytes, and in particular to a method for preparing a sulfide solid electrolyte. Background Art

[0002] Solid-state batteries are attracting increasing attention due to their higher energy density and safety, while sulfide solid electrolytes have become a research and development focus due to their high ionic conductivity, wide range of composition variations, and relatively low raw material costs.

[0003] The preparation methods of sulfide solid electrolytes mainly include melt quenching, liquid phase method and ball milling method. Common raw materials include lithium sulfide, phosphorus pentasulfide and other substances that are very sensitive to water vapor and air, so the preparation process needs to be carried out under the protection of an inert atmosphere. Among them, the liquid phase method is suitable for large-scale production, but the prepared sulfide electrolyte exhibits poor ionic conductivity, which is mainly due to the presence of residual organic molecules during the preparation process. The ball milling reaction precursors can be well mixed, and through annealing treatment, the ionic conductivity and crystallinity of the sulfide prepared by mechanical ball milling are improved, but this method is not practical for actual production. The melt quenching method is simple to operate and is very suitable for the preparation of glassy sulfide electrolytes, but it requires a higher operating temperature, is prone to impurities, and the crystallinity of the obtained material is also difficult to control. Therefore, the development of a preparation process suitable for large-scale production and capable of ensuring the performance of sulfide solid electrolytes is of great significance to the development of sulfide solid electrolytes.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a sulfide solid electrolyte to solve the technical problems existing in the prior art, such as unsuitability for large-scale production and poor performance of the sulfide solid electrolyte.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0007] The preparation method of the sulfide solid electrolyte comprises the following steps:

[0008] The sulfide solid electrolyte precursor is subjected to electromagnetic wave treatment at least twice under anhydrous and oxygen-free conditions; the preparation of the sulfide solid electrolyte precursor comprises: subjecting the sulfide solid electrolyte raw materials to mixed ball milling treatment.

[0009] The present invention uses electromagnetic waves of a specific frequency to treat a sulfide solid electrolyte precursor. As the sulfide reacts to the electromagnetic waves, it generates instantaneous heat, resulting in a noticeable color change in the raw material mixture, producing a glass-ceramic sulfide solid electrolyte. This preparation method is suitable for large-scale production, and the resulting sulfide solid electrolyte exhibits excellent ionic conductivity and other properties.

[0010] In a specific embodiment of the present invention, the frequency of the electromagnetic wave treatment is 0.8 to 30 GHz; and the time of a single electromagnetic wave treatment is 0.5 to 30 minutes.

[0011] In a specific embodiment of the present invention, the preparation of the sulfide solid electrolyte precursor includes: mixing and ball-milling the sulfide solid electrolyte raw materials, crushing and screening, and pressing to obtain the sulfide solid electrolyte precursor.

[0012] In a specific embodiment of the present invention, the conditions of the mixed ball milling treatment include: a rotation speed of 150 to 1000 rpm, a ball-to-material ratio of (1 to 50):1, and a ball milling time of 1 to 50 h.

[0013] In a specific embodiment of the present invention, during the mixing ball milling process, scraping treatment is performed every 0.5 to 1 hour.

[0014] In a specific embodiment of the present invention, the particle size of the crushed and sieved material is 20 to 1000 mesh.

[0015] In a specific embodiment of the present invention, the conditions for the compression molding include: a pressure of 0.1 to 300 MPa.

[0016] In a specific embodiment of the present invention, between two adjacent electromagnetic wave treatments, the material after the electromagnetic wave treatment is further crushed and screened, and then pressed and formed into a block precursor.

[0017] In a specific embodiment of the present invention, the sulfide solid electrolyte raw material includes any one of a binary component system and a ternary component system or above.

[0018] In a specific embodiment of the present invention, when the sulfide solid electrolyte raw material is a binary component system, it includes any one of P2S5, SiS2 and B2S3 and Li2S.

[0019] In a specific embodiment of the present invention, when the sulfide solid electrolyte raw material is a ternary component system, it includes a binary component system raw material and a doping component; the doping component is selected from M2S a 、Li b M'O cand LiA; wherein, M is Ge, Sn or Si, a is 2, 3 or 4; M' is Si, B, Ge or P, b and c satisfy 2c-b = 3 or 4 or 5, and b and c are integers; A is Cl, Br or I.

[0020] In a specific embodiment of the present invention, when the sulfide solid electrolyte raw material is a quaternary component system, it includes Li2S, P2S5, S and Ge.

[0021] In a specific embodiment of the present invention, when the sulfide solid electrolyte raw material is a five-component component, it includes Li2S, P2S5, S, Si and LiCl.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The preparation method of the sulfide solid electrolyte of the present invention is different from the traditional melt quenching process. It is treated at least twice by electromagnetic waves without heating to a high temperature. By taking advantage of the material's absorption characteristics of electromagnetic waves, a uniform and high-conductivity sulfide solid electrolyte can be obtained simply and quickly;

[0024] (2) The present invention improves the uniformity of the sulfide solid electrolyte by adopting electromagnetic wave treatment and ball milling treatment, and increases the proportion of the glassy state in the sulfide solid electrolyte, thereby significantly improving the ionic conductivity;

[0025] (3) The preparation method of the sulfide solid electrolyte of the present invention is simple to operate, can be synthesized in large quantities, and is easy to industrialize. At the same time, it can broaden the raw material components of the sulfide solid electrolyte, and can use elemental sulfur, elemental germanium, etc. as raw materials, further reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a state diagram of each stage in the preparation process of the sulfide solid electrolyte in Example 1 of the present invention;

[0028] Figure 2 The XRD pattern of the Li6PS5Cl sulfide solid electrolyte prepared in Example 1 of the present invention;

[0029] Figure 3XRD patterns of the Li6PS5Cl sulfide solid electrolytes prepared in Example 2 and Example 1 of the present invention;

[0030] Figure 4 XRD patterns of the Li6PS5Cl sulfide solid electrolytes prepared in Example 4 and Example 3 of the present invention;

[0031] Figure 5 This is the XRD pattern of the sulfide solid electrolyte prepared in Example 5 of the present invention;

[0032] Figure 6 This is the XRD pattern of the sulfide solid electrolyte prepared in Example 6 of the present invention;

[0033] Figure 7 This is the XRD pattern of the sulfide solid electrolyte prepared in Example 7 of the present invention;

[0034] Figure 8 This is the XRD pattern of the sulfide solid electrolyte prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0035] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified as manufacturers are conventional products that can be purchased commercially.

[0036] The preparation method of the sulfide solid electrolyte comprises the following steps:

[0037] The sulfide solid electrolyte precursor is subjected to electromagnetic wave treatment at least twice under anhydrous and oxygen-free conditions; the preparation of the sulfide solid electrolyte precursor comprises: subjecting the sulfide solid electrolyte raw materials to mixed ball milling treatment.

[0038] The present invention uses electromagnetic waves to treat a sulfide solid electrolyte precursor. As the sulfide reacts to the electromagnetic waves, it generates instantaneous heat, resulting in a noticeable color change in the raw material mixture, producing a glass-ceramic sulfide solid electrolyte. This preparation method is suitable for large-scale production, and the resulting sulfide solid electrolyte exhibits excellent ionic conductivity and other properties.

[0039] For example, in different embodiments, the number of electromagnetic wave treatments is two or three times. The above number of electromagnetic wave treatments can ensure both production efficiency and the performance of the sulfide solid electrolyte.

[0040] In a specific embodiment of the present invention, the frequency of the electromagnetic wave treatment is 0.8 to 30 GHz; and the time of a single electromagnetic wave treatment is 0.5 to 30 minutes.

[0041] For example, in different embodiments, the frequency of electromagnetic wave treatment can be 800MHz, 900MHz, 1000MHz, 1200MHz, 1400MHz, 1500MHz, 1600MHz, 1800MHz, 2000MHz, 2200MHz, 2400MHz, 2450MHz, 2500MHz, 2600MHz, 2800MHz, 3000MHz, 3200MHz, etc.; the time of a single electromagnetic wave treatment can be 0.5min, 1min, 5min, 8min, 10min, 15min, 20min, 25min, 30min, etc.

[0042] The amount of heat generated by a substance in an electromagnetic field of a specific frequency is closely related to the type of material and its dielectric properties. Specifically, electromagnetic waves of a specific frequency have a selective heating effect on materials. The energy band differences of different semiconductor materials correspond to different electromagnetic wave bands. Sulfide semiconductor materials, in particular, can achieve specific absorption within a certain frequency range, exhibiting rapid electron transitions between different energy levels and the separation of electrons and atomic nuclei. The overall temperature of the sulfide solid electrolyte material rises rapidly when absorbing electromagnetic waves of a specific frequency.

[0043] In a preferred embodiment of the present invention, the duration of a single electromagnetic wave treatment is 1 to 15 minutes, such as 1 to 10 minutes, and further such as 1 to 8 minutes.

[0044] In a specific embodiment of the present invention, the power of the electromagnetic wave treatment can be 500W to 10kW, such as 500W, 700W, 1kW, 5kW, 10kW, etc.

[0045] In actual operation, the requirements for the anhydrous and oxygen-free conditions are: the moisture content is less than 1 ppm, and the oxygen content is less than 1 ppm.

[0046] In a specific embodiment of the present invention, the preparation of the sulfide solid electrolyte precursor includes: mixing and ball-milling the sulfide solid electrolyte raw materials, crushing and screening, and pressing to obtain the sulfide solid electrolyte precursor.

[0047] In a specific embodiment of the present invention, the conditions of the mixed ball milling treatment include: a rotation speed of 150 to 1000 rpm, a ball-to-material ratio of (1 to 50):1, and a ball milling time of 1 to 50 h.

[0048] For example, in different embodiments, the rotation speed of the mixed ball milling process can be 150rpm, 200rpm, 300rpm, 400rpm, 500rpm, 600rpm, 700rpm, 800rpm, 900rpm, 1000rpm, etc.; the ball-to-material ratio can be 1:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, etc.; the ball milling time can be 1h, 4h, 10h, 15h, 20h, 30h, 40h, 50h, etc.

[0049] In actual operation, when the rotation speed of the mixing ball mill is too high, such as exceeding the above-mentioned rotation speed range, the material becomes very hard under the force of the ball milling beads, and the scraping operation cannot be performed; and because the powder of the sulfide solid electrolyte raw material easily agglomerates during the ball milling process, when it becomes hard, the effective ball milling time is further reduced, and the uniformity of the material mixing is deteriorated.

[0050] In a preferred embodiment of the present invention, the conditions for the mixed ball milling treatment include: a rotation speed of 200 to 600 rpm, a ball-to-material ratio of (5 to 20):1, and a ball milling time of 4 to 20 hours.

[0051] In a specific embodiment of the present invention, during the mixing ball milling process, scraping treatment is performed every 0.5 to 1 hour. For example, in different embodiments, during the mixing ball milling process, scraping treatment is performed every 0.5 hour, 0.8 hour, 1 hour, etc., so that the agglomerated material is in a powder state and continues the ball milling process, thereby further improving the mixing uniformity.

[0052] In practice, the mixed ball milling process can be performed in a ball milling jar made of, for example, zirconia, stainless steel, or agate. The abrasive can be zirconia balls, stainless steel, agate, or corundum. After the ball milling process, the abrasive is separated, and the sulfide solid electrolyte precursor is placed in a sintering container for electromagnetic wave treatment. For example, the sintering container can be a quartz container, ceramic container, glass container, or other electromagnetic wave-resistant container.

[0053] In a specific embodiment of the present invention, the particle size of the crushed and sieved material is 20 to 1000 mesh.

[0054] For example, in different embodiments, the particle size of the crushed and sieved particles can be 20 mesh, 100 mesh, 200 mesh, 300 mesh, 400 mesh, 500 mesh, 600 mesh, 700 mesh, 800 mesh, 900 mesh, 1000 mesh, and the like.

[0055] In a preferred embodiment of the present invention, the particle size of the crushed and sieved particles is 200-600 meshes.

[0056] In a specific embodiment of the present invention, the conditions for the compression molding include: a pressure of 0.1 to 300 MPa, preferably 3 to 20 MPa.

[0057] In actual operation, a mold can be used for pressing and molding to press the crushed and sieved sulfide solid electrolyte raw materials into blocks.

[0058] In a specific embodiment of the present invention, between two adjacent electromagnetic wave treatments, the material after the electromagnetic wave treatment is further crushed and screened, and then pressed and formed into a block precursor.

[0059] The present invention performs crushing and screening on the material after electromagnetic wave treatment, presses and forms it, and then performs electromagnetic wave treatment. The uniformity of the obtained sulfide solid electrolyte is significantly improved, and the ionic conductivity is increased by 1 to 3 times.

[0060] In actual operation, the conditions for the crushing and screening treatment between two adjacent electromagnetic wave treatments can be the same as the crushing and screening operation after the mixed ball milling treatment.

[0061] In a specific embodiment of the present invention, the sulfide solid electrolyte raw material includes any one of a binary component system and a ternary component or higher system, wherein the ternary component or higher system includes any one of a ternary component, a quaternary component, and a quinary component.

[0062] In a specific embodiment of the present invention, when the sulfide solid electrolyte raw material is a binary component system, it includes any one of P2S5, SiS2, and B2S3, and Li2S. For example, in terms of molar ratio, xLi2S—(1-x)P2S5, yLi2S—(1-y)SiS2, and zLi2S—(1-z)B2S3; wherein x is 0.1 to 0.6, y is 0.4 to 0.9, and z is 0.2 to 0.8.

[0063] In a preferred embodiment of the present invention, x is 0.3 to 0.5; y is 0.5 to 0.8; and z is 0.5 to 0.75.

[0064] In a specific embodiment of the present invention, when the sulfide solid electrolyte raw material is a ternary component system, it includes a binary component system raw material and a doping component; the doping component is selected from M2S a 、Li b M'O cand LiA; wherein M is Ge, Sn, or Si, a is 2, 3, or 4; M' is Si, B, Ge, or P, b and c satisfy 2c-b=3, 4, or 5, and b and c are both integers; and A is Cl, Br, or I. Furthermore, in the ternary component system, by molar percentage, the amount of Li2S is 10% to 80%, the amount of P2S5 is 5% to 90%, and the amount of the doping component is 1% to 50%.

[0065] In a preferred embodiment of the present invention, in the ternary component system, the amount of Li2S is 30% to 70%, the amount of any one of P2S5, SiS2 and B2S3 is 10% to 80%; the doping component M2S a The dosage is 10% to 30%, Li b M'O c The dosage of is 10% to 40%, and the dosage of LiA is 8% to 18%.

[0066] In a specific embodiment of the present invention, the sulfide solid electrolyte raw material, when a quaternary component system is used, includes Li2S, P2S5, S, and Ge. Furthermore, in the quaternary component system, the amount of Li2S is 10% to 80%, the amount of P2S5 is 1% to 20%, the amount of S is 5% to 60%, and the amount of Ge is 0.1% to 40%.

[0067] In a preferred embodiment of the present invention, in the quaternary component system, based on molar percentage, the amount of Li2S is 50% to 80%, the amount of P2S5 is 5% to 15%, the amount of S is 10% to 40%, and the amount of Ge is 2% to 20%.

[0068] In a specific embodiment of the present invention, the sulfide solid electrolyte raw material, when a five-component system, includes Li2S, P2S5, S, Si, and LiCl. Furthermore, in the five-component system, the amount of Li2S is 10% to 80%, the amount of P2S5 is 1% to 20%, the amount of S is 5% to 60%, the amount of Si is 5% to 40%, and the amount of LiCl is 0.1% to 18%.

[0069] In a preferred embodiment of the present invention, in the five-component system, based on molar percentage, the amount of Li2S is 50% to 80%, the amount of P2S5 is 5% to 15%, the amount of S is 10% to 40%, the amount of Si is 10% to 20%, and the amount of LiCl is 1% to 8%.

[0070] In a specific embodiment of the present invention, after the electromagnetic wave treatment, the obtained sulfide solid electrolyte is pulverized under a protective atmosphere.

[0071] In a specific embodiment of the present invention, when the sulfide solid electrolyte is a fast ion conductor (such as Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 ), the frequency of electromagnetic wave treatment is 0.915GHz±0.1GHz; when the sulfide solid electrolyte is a sulfide-germanium electrolyte (such as Li 5.5 S 4.5 PCl 1.5 ), the frequency of electromagnetic wave processing is 2.45GHz±0.3GHz.

[0072] Different sulfide solid electrolytes have different absorption effects on electromagnetic waves of different frequencies. Using the above-mentioned appropriate specific frequency electromagnetic waves to process the raw materials can ensure both the processability and the properties of the sulfide solid electrolyte.

[0073] Example 1

[0074] This embodiment provides a method for preparing a sulfide solid electrolyte Li6S5PCl, comprising the following steps:

[0075] (a) In an argon-dried atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), Li2S, P2S5, and LiCl (each with a purity of greater than 99%) were weighed in a molar ratio of 5:1:2 and placed in a 500 mL stainless steel ball mill (ball-to-material ratio of 5:1). The mill was sealed and subjected to high-energy ball milling at 500 rpm for 8 h. During the milling process, the material was scraped every h to reduce the agglomerated material to powder and then continued to be ball milled.

[0076] (b) Separating the abrasive from the ball-milled material of step (a), pressing the resulting sulfide solid electrolyte precursor into a block material using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and loading it into a quartz container.

[0077] (c) A quartz container containing the sulfide solid electrolyte precursor was placed in a 2450 MHz microwave reactor and subjected to electromagnetic wave treatment at 700 W for 10 min. The electromagnetic wave treatment was stopped, and after cooling to room temperature, the product was ground in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieved through 300 mesh to obtain a sulfide solid electrolyte.

[0078] Figure 1This is a state diagram of each stage in the preparation process of the sulfide solid electrolyte of Example 1 of the present invention, wherein (A) is the material after ball milling in step (a), (B) is the material after electromagnetic wave treatment in step (c), (C) is the material after crushing in step (c), and (D) is the material after screening in step (c). Figure 1 It can be seen that the color of the material after ball milling treatment is yellow-green. As the sulfide absorbs the electromagnetic waves, heat is generated instantly, and the color of the original material mixture can be clearly seen to change. The color of the material after electromagnetic wave treatment is gray-black.

[0079] Example 2

[0080] This embodiment provides a method for preparing a sulfide solid electrolyte Li6S5PCl, comprising the following steps:

[0081] Referring to steps (a) to (c) of Example 1, a sulfide solid electrolyte was obtained;

[0082] (d) pressing the sieved sulfide solid electrolyte obtained in step (c) into a block material again using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and placing it into a quartz container;

[0083] (e) placing the quartz container containing the sulfide solid electrolyte precursor obtained in step (d) in a 2450 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 700 W for 10 min. After stopping the electromagnetic wave treatment and cooling it to room temperature, the product was ground in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieved through 300 mesh to obtain a sulfide solid electrolyte.

[0084] Example 3

[0085] This embodiment provides a method for preparing a sulfide solid electrolyte Li6S5PCl, referring to Example 1, with the following differences:

[0086] In step (c), the electromagnetic wave treatment time is 30 minutes.

[0087] Example 4

[0088] This embodiment provides a method for preparing a sulfide solid electrolyte Li6S5PCl, referring to Example 1, with the following differences:

[0089] In step (c), the electromagnetic wave treatment time is 15 minutes.

[0090] Example 5

[0091] This embodiment provides a sulfide solid electrolyte Li 5.5 S 4.5PCl 1.5 The preparation method comprises the following steps:

[0092] (a) In an argon-dried atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), Li2S, P2S5, and LiCl (each with a purity greater than 99%) were weighed in a molar ratio of 4:1:3 and placed in a 500 mL stainless steel ball mill (ball-to-material ratio of 5:1). The mill was sealed and subjected to high-energy ball milling at 500 rpm for 8 h.

[0093] (b) Separating the abrasive from the ball-milled material of step (a), pressing the resulting sulfide solid electrolyte precursor into a block material using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and loading it into a quartz container.

[0094] (c) Placing the quartz container containing the sulfide solid electrolyte precursor in a 2450 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 700 W for 10 min, stopping the electromagnetic wave treatment, cooling it to room temperature, and then grinding it in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieving it through a 300 mesh sieve to obtain a sulfide solid electrolyte.

[0095] (d) pressing the sieved sulfide solid electrolyte obtained in step (c) into a block material again using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and placing it into a quartz container;

[0096] (e) placing the quartz container containing the sulfide solid electrolyte precursor obtained in step (d) in a 2450 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 700 W for 10 min. After stopping the electromagnetic wave treatment and cooling it to room temperature, the product was ground in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieved through 300 mesh to obtain a sulfide solid electrolyte.

[0097] Example 6

[0098] This embodiment provides a sulfide solid electrolyte Li 5.5 S 4.5 PCl 1.5 The preparation method comprises the following steps:

[0099] (a) In an argon-dried atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), Li2S, P2S5, and LiCl (each with a purity of greater than 99%) were weighed in a molar ratio of 4:1:3 and placed in a 500 mL stainless steel ball mill (ball-to-material ratio of 5:1). The mill was sealed and subjected to high-energy ball milling at 500 rpm for 8 h. The material was scraped every h during the milling process to reduce the agglomerated material to powder and continue to be ball milled.

[0100] (b) Separating the abrasive from the ball-milled material of step (a), pressing the resulting sulfide solid electrolyte precursor into a block material using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and loading it into a quartz container.

[0101] (c) Placing the quartz container containing the sulfide solid electrolyte precursor in a 2450 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 700 W for 10 min, stopping the electromagnetic wave treatment, cooling it to room temperature, and then grinding it in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieving it through a 300 mesh sieve to obtain a sulfide solid electrolyte.

[0102] (d) pressing the sieved sulfide solid electrolyte obtained in step (c) into a block material again using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and placing it into a quartz container;

[0103] (e) placing the quartz container containing the sulfide solid electrolyte precursor obtained in step (d) in a 2450 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 700 W for 10 min. After stopping the electromagnetic wave treatment and cooling it to room temperature, the product was ground in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieved through 300 mesh to obtain a sulfide solid electrolyte.

[0104] Example 7

[0105] This embodiment provides a sulfide solid electrolyte Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 The preparation method comprises the following steps:

[0106] (a) In an argon-dried atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), Li2S, P2S5, LiCl, Si, and S with a purity of greater than 99% were weighed in a molar ratio of 154:12:5:24:48 and placed in a 500 mL stainless steel ball mill (ball-to-material ratio of 5:1). The mill was sealed and subjected to high-energy ball milling at 500 rpm for 8 h. The material was scraped every h during the milling process to reduce the agglomerated material to powder and continue ball milling.

[0107] (b) Separating the abrasive from the ball-milled material of step (a), pressing the resulting sulfide solid electrolyte precursor into a block material using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and loading it into a quartz container.

[0108] (c) Placing the quartz container containing the sulfide solid electrolyte precursor in a 915 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 10 kW for 10 min, stopping the electromagnetic wave treatment, cooling it to room temperature, and then grinding it in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieving it through a 300 mesh sieve to obtain a sulfide solid electrolyte.

[0109] (d) pressing the sieved sulfide solid electrolyte obtained in step (c) into a block material again using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and placing it into a quartz container;

[0110] (e) placing the quartz container containing the sulfide solid electrolyte precursor obtained in step (d) in a 915 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 10 kW for 10 min. After stopping the electromagnetic wave treatment and cooling it to room temperature, the product was ground in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieved through 300 mesh to obtain a sulfide solid electrolyte.

[0111] Example 8

[0112] This embodiment provides a sulfide solid electrolyte Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 The preparation method comprises the following steps:

[0113] (a) In an argon-dried atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), Li2S, P2S5, LiCl, Si, and S with a purity of greater than 99% were weighed in a molar ratio of 154:12:5:24:48 and placed in a 500 mL stainless steel ball mill (ball-to-material ratio of 5:1). The mill was sealed and subjected to high-energy ball milling at 500 rpm for 8 h. The material was scraped every h during the milling process to reduce the agglomerated material to powder and continue ball milling.

[0114] (b) Separating the abrasive from the ball-milled material of step (a), pressing the resulting sulfide solid electrolyte precursor into a block material using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and loading it into a quartz container.

[0115] (c) Placing the quartz container containing the sulfide solid electrolyte precursor in a 2450 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 10 kW for 10 min, stopping the electromagnetic wave treatment, cooling it to room temperature, and then grinding it in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieving it through a 300 mesh sieve to obtain a sulfide solid electrolyte.

[0116] (d) pressing the sieved sulfide solid electrolyte obtained in step (c) into a block material again using a mold at a pressure of 5 MPa, placing the block material in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and placing it into a quartz container;

[0117] (e) placing the quartz container containing the sulfide solid electrolyte precursor obtained in step (d) in a 2450 MHz electromagnetic wave reactor and subjecting it to electromagnetic wave treatment at 10 kW for 10 min. After stopping the electromagnetic wave treatment and cooling it to room temperature, the product was ground in an argon dry atmosphere (moisture content less than 1 ppm, oxygen content less than 1 ppm), and sieved through 300 mesh to obtain a sulfide solid electrolyte.

[0118] Comparative Example 1

[0119] Comparative Example 1 provides a method for preparing a sulfide solid electrolyte Li6S5PCl, comprising the following steps:

[0120] Refer to steps (a) and (b) of Example 1; then place the quartz container containing the sulfide solid electrolyte precursor obtained in step (b) in a muffle furnace and sinter at 460° C. for 10 hours.

[0121] Experimental example

[0122] In order to compare and illustrate the differences in the preparation methods of the sulfide solid electrolytes of different embodiments and comparative examples, the performance of the sulfide solid electrolytes prepared in each embodiment and comparative example was tested. The XRD patterns of the sulfide solid electrolytes finally prepared in each embodiment and comparative example are shown in FIG. Figures 2 to 8 , the conductivity test results are shown in Table 1.

[0123] Conductivity test method: weigh 0.1g of test sample The samples were pressed at 8 MPa in a tableting mold (with carbon-coated aluminum foil at both ends). The pressed electrolyte sheets were then packaged in a 2016 button cell case (nickel foam was used to adjust the thickness) and transferred for impedance testing. The test frequency range was 1 Hz to 1 MHz, with an amplitude of 5 mV.

[0124] Figure 2 The XRD pattern of the Li6PS5Cl sulfide solid electrolyte prepared in Example 1 of the present invention. Figure 2 It can be seen that the product Li6PS5Cl obtained by one electromagnetic wave treatment is not pure enough and contains Li2S impurities. Figure 2 It can be seen that after two electromagnetic wave treatments, the Li2S phase in the product Li6PS5Cl disappears and the purity of the product is improved. Figure 4 The XRD patterns of the Li6PS5Cl sulfide solid electrolytes prepared in Example 4 and Example 3 of the present invention are as follows: Figure 4 It can be seen that using a single sintering method, even if the sintering time is extended, it is impossible to completely remove the Li2S impurity phase and improve the product purity. Figure 5 and Figure 6 The XRD patterns of the sulfide solid electrolytes prepared in Example 5 and Example 6 respectively show that if scraping is not performed during the mixing ball milling process, the material mixing uniformity is relatively poor, resulting in residual Li2S impurity phase in the product. Figure 7 This is the XRD pattern of the sulfide solid electrolyte prepared in Example 7 of the present invention. Figure 8 This is the XRD spectrum of the sulfide solid electrolyte prepared in Comparative Example 1 of the present invention. As can be seen from the figure, the present invention shortens the process flow by performing two electromagnetic wave treatments. At the same time, the obtained product sulfide solid electrolyte has less impurities and good uniformity.

[0125] Table 1 Conductivity test results of different sulfide solid electrolytes

[0126] serial number Conductivity (S / cm) Example 1 <![CDATA[1.03×10 -3 ]]> Example 2 <![CDATA[3.73×10 -3 ]]> Example 3 <![CDATA[1.14×10 -3 ]]> Example 4 <![CDATA[1.10×10 -3 ]]> Example 5 <![CDATA[4.3×10 -3 ]]> Example 6 <![CDATA[1.10×10 -2 ]]> Example 7 <![CDATA[9.56×10 -3 ]]> Example 8 <![CDATA[3.96×10 -4 ]]> Comparative Example 1 <![CDATA[2.33×10 -3 ]]>

[0127] The above results demonstrate that the present method for preparing a sulfide solid electrolyte differs from conventional melt-quenching processes by using electromagnetic waves for at least two treatments, eliminating the need for high-temperature heating. Leveraging the material's absorption of electromagnetic waves, this method allows for the rapid and simple production of a uniform, highly conductive sulfide solid electrolyte. By employing specific electromagnetic wave treatments and ball milling processes, the uniformity of the sulfide solid electrolyte is improved, the proportion of the glassy phase in the sulfide solid electrolyte is increased, and ionic conductivity is significantly enhanced.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a sulfide solid electrolyte, characterized in that: The steps include: The sulfide solid electrolyte precursor is subjected to electromagnetic wave treatment at least twice under anhydrous and oxygen-free conditions, with a single electromagnetic wave treatment time of 1 to 15 minutes. The preparation of the sulfide solid electrolyte precursor comprises: mixing and ball-milling the sulfide solid electrolyte raw materials, crushing and screening, and pressing and molding to obtain the sulfide solid electrolyte precursor; When the sulfide solid electrolyte is a fast ion conductor, the frequency of the electromagnetic wave treatment is 0.915 GHz ± 0.1 GHz; when the sulfide solid electrolyte is an argyrodite electrolyte, the frequency of the electromagnetic wave treatment is 2.45 GHz ± 0.3 GHz.

2. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The number of electromagnetic wave treatments is two or three times.

3. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The conditions of the mixed ball milling treatment include: a rotation speed of 150-1000 rpm, a ball-to-material ratio of (1-50):1, and a ball milling time of 1-50 hours.

4. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The conditions of the mixed ball milling treatment include: a rotation speed of 200-600 rpm, a ball-to-material ratio of (5-20):1, and a ball milling time of 4-20 hours.

5. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: During the mixing ball milling process, scraping treatment was performed every 0.5 to 1 hour.

6. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The particle size of the crushed and sieved particles is 20-1000 meshes.

7. The method for preparing a sulfide solid electrolyte according to claim 6, wherein: The compression molding conditions include: a pressure of 0.1-300 MPa.

8. The method for preparing a sulfide solid electrolyte according to claim 7, wherein: The pressure is 3~20MPa.

9. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: Between two adjacent electromagnetic wave treatments, the process further includes: crushing and screening the material after the electromagnetic wave treatment, and then pressing and molding to obtain a block precursor; The particle size of the crushed and sieved particles is 20 to 1000 mesh; The pressure of the compression molding is 3-20 MPa.

10. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The sulfide solid electrolyte raw material includes any one of a binary component system and a ternary component or higher system.

11. The method for preparing a sulfide solid electrolyte according to claim 10, characterized in that: When the sulfide solid electrolyte raw material is a binary component system, it includes any one of P2S5, SiS2 and B2S3 and Li2S.

12. The method for preparing a sulfide solid electrolyte according to claim 10, wherein: When the sulfide solid electrolyte raw material is a ternary component system, it includes a binary component system raw material and a doping component; the doping component is selected from M2S a 、Li b M'O c and LiA; wherein, M is Ge, Sn or Si, a is 2, 3 or 4; M' is Si, B, Ge or P, b and c satisfy 2c-b = 3 or 4 or 5, and b and c are integers; A is Cl, Br or I.

13. The method for preparing a sulfide solid electrolyte according to claim 10, wherein: When the sulfide solid electrolyte raw material is a quaternary component, it includes Li2S, P2S5, S and Ge.

14. The method for preparing a sulfide solid electrolyte according to claim 10, characterized in that: When the sulfide solid electrolyte raw material is a five-component component, it includes Li2S, P2S5, S, Si and LiCl.

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