Argyrodite type sulfide solid electrolyte and preparation method and application thereof

Abstract

The invention belongs to the technical field of all-solid-state battery materials, and discloses argyrodite type sulfide solid electrolyte as well as a preparation method and application thereof. A lithium source 1, a lithium source 2, a sulfur source, a phosphorus source and LiX (X is Cl, Br or I) which are low in cost are used as raw materials, a Li2S raw material which is high in cost is replaced, and the argyrodite type sulfide solid electrolyte is prepared through vacuum ball milling, sintering and grinding. The argyrodite-type sulfide solid electrolyte has the advantages of low raw material cost, strong reaction activity and simple preparation process, and the prepared argyrodite-type sulfide solid electrolyte has excellent ionic conductivity, strong air stability and high (electro-chemical) stability, has excellent electrochemical performance when being applied to all-solid-state lithium batteries, and can be widely applied to all-solid-state lithium batteries. And large-scale application of the all-solid-state lithium battery is promoted.

Description

Technical Field

[0001] This invention belongs to the field of all-solid-state battery material technology, specifically relating to a method for preparing a silver-germanium sulfide solid electrolyte using low-cost raw materials to replace lithium sulfide, as well as its products and applications. Background Technology

[0002] Lithium-ion batteries, as the current mainstream energy storage technology, are widely used in consumer electronics, electric vehicles, and energy storage systems due to their high energy density and long cycle life. However, traditional liquid electrolytes pose safety hazards such as flammability, explosiveness, and leakage, and their energy density is approaching its theoretical limit, making it difficult to meet the high safety and high energy density requirements of large-scale energy storage. Solid-state electrolytes, due to their non-flammable properties and wide electrochemical window, have become a key direction for overcoming the bottlenecks of liquid batteries. Among them, sulfide solid-state electrolytes have excellent room-temperature ionic conductivity (generally higher than 10). -3 With its good interfacial contact properties and relatively simple synthesis conditions, it is considered the closest technology to commercialization among all-solid-state lithium batteries (ASSLB).

[0003] Currently, sulfide solid electrolytes face challenges such as poor air stability, narrow electrochemical windows, and interfacial instability. Their synthesis heavily relies on lithium sulfide (Li₂S) as a key raw material. For example, the preparation of silver sulfide germanite-type (Li₆PS₅Cl) electrolytes requires Li₂S, P₂S₅, and LiCl as precursors, achieved through high-energy ball milling or high-temperature solid-phase methods. However, lithium sulfide is expensive, accounting for over 80% of the total cost of sulfide electrolytes, severely hindering their industrialization. Furthermore, traditional synthesis methods suffer from high energy consumption and low product purity. While liquid-phase methods can improve product morphology uniformity, they require large amounts of volatile solvents (such as acetonitrile and CS₂), which not only easily cause environmental pollution but may also lead to solvent residues, thus affecting electrolyte stability.

[0004] In recent years, researchers have focused on reducing the dependence of sulfide solid electrolyte synthesis on lithium sulfide through raw material substitution and process innovation. For example, researchers (Liu Fangyang et al., A method for preparing a sulfide solid electrolyte of silver-germanium sulfide type, CN113321485A, 2021.) used CS2 as the sulfur source to replace Li2S, combining vacuum wet ball milling and solid-phase ball milling techniques to prepare solid electrolytes. However, the inherent toxicity and flammability and explosiveness of the CS2 solvent fundamentally limit the economic viability and feasibility of this technology for industrial-scale transformation. Another study (Li, H et al., A Cost-Effective Sulfide Solid Electrolyte Li7P3S) 7.5 O 3.5With low density and excellent anode compatibility. Angew. Chem. Int. Ed. 2024, 63, e202407892.) Synthesis of Li7P3S via direct reaction of Li2O and P2S5. 7.5 O 3.5 Solid electrolytes are used, which avoids the expensive Li₂S while offering low density and good lithium metal stability, but its ionic conductivity is low (4.58 × 10⁻⁶). -4 S / cm). In addition, Sun et al (Sun, Z et al, Insights on the Properties of the O-Doped Argyrodite Sulfide SolidElectrolytes (Li6PS 5-x ClO x (x=0-1). ACS Appl. Mater. Interfaces. 2021, 13, 54924-54935.) By partially replacing Li2S in the Li6PS5Cl feedstock with Li2O, Li6PS can be synthesized. 4.75 Cl 0.25 Its ionic conductivity at 25℃ reaches 4.73×10⁻⁶. -3 S / cm, compared with unmodified Li6PS5Cl (4.2×10⁻⁶). -3 While the S / cm ratio is comparable, this method still relies on high-purity Li2S raw materials, failing to fundamentally overcome the raw material bottleneck.

[0005] Therefore, developing a low-cost, environmentally friendly, and scalable method for preparing sulfide solid electrolytes based on non-sulfide lithium raw materials, silver-germanium sulfide, has become crucial for advancing the industrialization of all-solid-state lithium batteries. Breakthroughs in this technology require achieving a balance between raw material selection, process simplification, environmental friendliness, and electrochemical performance, thereby effectively propelling all-solid-state lithium batteries from the laboratory to industrialization. Summary of the Invention

[0006] The purpose of this invention is to provide a low-cost preparation method for silver sulfide-germanium sulfide solid electrolytes based on non-lithium sulfide raw materials. This method overcomes the dependence of traditional silver sulfide-germanium sulfide solid electrolytes on lithium sulfide raw materials, employing a low-cost, environmentally friendly lithium source alternative. Furthermore, it eliminates the need for complex high-temperature and high-pressure processing and the addition of any catalysts, maximizing the purity of the raw materials. The precursor is obtained through simple high-energy ball milling, followed by annealing, sintering, and grinding at a specific temperature. The resulting silver sulfide-germanium sulfide solid electrolyte exhibits high purity and excellent ionic conductivity at room temperature. Compared to traditional silver sulfide-germanium sulfide solid electrolytes, its cost can be reduced by approximately 90%.

[0007] The technical solution adopted by the present invention to achieve the above-mentioned technical objectives is as follows: To achieve the above objectives, the present invention provides a method for preparing a sulfide solid electrolyte of the silver-germanium sulfide type, the method comprising the following steps: (1) Under an inert atmosphere, lithium source 1, lithium source 2, sulfur source, phosphorus source, LiX and grinding beads are added to a grinding jar, the grinding jar is sealed and evacuated, and then ball milling is performed to obtain a solid electrolyte precursor. (2) The solid electrolyte precursor obtained in step (1) is sintered in an inert atmosphere, then cooled to room temperature and ground into powder to obtain the sulfide solid electrolyte of the silver-germanium sulfide type.

[0008] Preferably, the lithium source 1 in step (1) is selected from one or more of Li2O, Li2O2, Li2CO3, and Li3PO4, and more preferably Li2O.

[0009] Preferably, the lithium source 2 in step (1) is selected from one or more of LiH, Li3N, LiNH2, CH3Li, and C6H5Li, and more preferably LiH.

[0010] Preferably, the sulfur source in step (1) is selected from one or a combination of S and thiourea, and more preferably S.

[0011] Preferably, the phosphorus source in step (1) is selected from one or a combination of P2S5 and P, and more preferably P2S5.

[0012] Preferably, in step (1), X in LiX is at least one of Cl, Br or I.

[0013] Furthermore, the molar ratio of lithium source 1, lithium source 2, sulfur source, phosphorus source and LiX is 5~0.2:0~7.6:0~3.8:1:1.5~3.

[0014] Preferably, in step (1), the ball-to-material ratio of the grinding balls to the material is 10-60:1, the grinding speed is 100-1200 r / min, and the grinding time is 6-60 hours.

[0015] Preferably, the grinding jar in step (1) is a grinding jar equipped with a gas valve for vacuuming, and the material is selected from stainless steel, corundum, agate, zirconium oxide, and polytetrafluoroethylene.

[0016] Preferably, in step (1), the sealed ball milling jar needs to be evacuated multiple times before the ball milling begins and after a certain period of ball milling, so that the ball milling jar maintains a certain degree of vacuum. More preferably, the evacuation is performed at intervals of 3 to 6 hours.

[0017] Preferably, in step (2), sintering involves raising the temperature to 300-600°C at a heating rate of 1-10°C / min, holding the temperature for 1-12 hours, and then allowing it to cool naturally.

[0018] Preferably, in step (2), grinding is performed using an agate mortar and pestle for 10-30 minutes to obtain sulfide solid electrolyte powder.

[0019] Preferably, the sulfide solid electrolyte Li is obtained from the silver-germanium sulfide. 3.0~7.5 PS 0.5~4.9 O 0.1~2.5 X 0.6~1.5 Wherein, X is at least one of Cl, Br or I.

[0020] The present invention also provides the application of the sulfide solid electrolyte of silver-germanium sulfide obtained by any of the above methods in all-solid-state lithium batteries.

[0021] Preferably, the method for preparing the all-solid-state lithium battery includes the following steps: (1) The positive electrode material, sulfide solid electrolyte powder and conductive agent are fully mixed in a mass ratio of 30~90:20~45:1~5 to obtain a composite positive electrode material; Preferably, the positive electrode material is selected from one or a mixture of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, and lithium nickel cobalt manganese oxide.

[0022] Preferably, the conductive agent is selected from one or a mixture of carbon black, carbon nanotubes, acetylene black, VGCF, Super P, conductive graphite, and carbon fiber.

[0023] Furthermore, the composite cathode material can be uniformly mixed with the cathode material by means of mechanical stirring, ball milling, grinding, etc.

[0024] (2) The sulfide solid electrolyte powder is evenly sprinkled into the tableting mold and held under pressure of 300~500 MPa for 30 s~60 s to compress the powder electrolyte into tablets to obtain the sulfide electrolyte layer. (3) Spread the composite positive electrode material evenly on one side of the solid electrolyte sheet and hold it under a pressure of 300~500 MPa for 60 s~120 s; (4) Press the negative electrode material onto the other side of the sulfide solid electrolyte sheet.

[0025] Preferably, the negative electrode material is selected from one or a mixture of two or more of lithium metal, lithium-containing alloys, graphite, hard carbon, silicon carbide, and lithium titanate. More preferably, the negative electrode material is lithium metal.

[0026] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows: (1) This invention uses low-cost lithium source 1, lithium source 2, sulfur source, phosphorus source and LiX (X is Cl, Br or I) as raw materials to replace the expensive Li2S raw material, which greatly reduces the cost of industrial production of sulfide solid electrolytes of silver-germanium ore type (90%).

[0027] (2) The lithium source 2, which is easy to decompose and generate gas, has strong reactivity and high raw material utilization. At the same time, by replacing Li2S with a certain amount of oxygen-containing lithium source 1, O doping is further realized. The resulting sulfide solid electrolyte has high ionic conductivity, strong air stability, and better stability for lithium.

[0028] (3) No solutions were used in the entire process of preparing the all-solid-state battery based on sulfide-germanium sulfide solid electrolyte. This process effectively avoids the reaction between the electrolyte and the solution, thereby preventing negative impacts on the electrolyte performance. At the same time, this method avoids the difficulties of handling organic solvents, simplifies the preparation process, and reduces potential risks and costs.

[0029] (4) The sulfide solid electrolyte prepared by the present invention has excellent ionic conductivity, strong air stability and high (electro)chemical stability. When applied to all-solid-state lithium batteries, it has excellent electrochemical performance. At the same time, the preparation method of the sulfide solid electrolyte of the present invention is simple, has strong reactivity and low raw material cost, which has extremely high economic advantages. It is suitable for large-scale production, accelerates the commercial application of all-solid-state lithium batteries and has significant economic benefits. Attached Figure Description

[0030] Figure 1 The XRD patterns are of Examples 1, 2, 3 and Comparative Example 1; Figure 2 EIS diagram of Example 2; Figure 3 EIS diagram of Example 5; Figure 4 The EIS plot is shown in Comparative Example 1; Figure 5 The graphs show the air stability test results for Example 3 and Comparative Example 2. Figure 6 The first charge-discharge curve of the assembled all-solid-state battery in Example 4; Figure 7 Cycle performance curves of the assembled all-solid-state battery in Example 4; Figure 8 This is a scanning electron microscope image of Example 5; Figure 9 This is a scanning electron microscope image of Example 6. Detailed Implementation

[0031] To better clarify and understand the objectives, process solutions, and advantages of this invention, the technical solutions and implementation methods of this invention will be further described clearly, completely, and in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the embodiments described in this invention are implemented under the premise of the technical solutions of this invention, providing detailed implementation methods and specific operating procedures, but are only some embodiments of this invention, not all embodiments. The specific implementation methods described are limited to illustrating and explaining this invention and do not limit this invention. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] Unless otherwise specified, the experimental methods and conditions used in the embodiments of this invention are conventional methods and conditions. The materials, reagents, and instruments used in the embodiments, unless otherwise specified, can be obtained commercially or prepared by conventional methods. The reaction conditions described in the invention can all achieve the reactions and obtain the desired products. Due to space limitations, some embodiments are listed below to further illustrate the advantages of the technical solution of this invention.

[0033] Example 1

[0034] Li₂O, LiH, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 3:4:2:1:2 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li₆PS. 3.5 O 1.5 Cl solid electrolyte powder. Its XRD pattern is shown in the attached figure. Figure 1 As shown, the XRD diffraction peaks of the sulfide sample correspond to the standard diffraction card of Li7PS6 (PDF#34-0688), proving the successful synthesis of a sulfide solid electrolyte with a sulfide-germanium sulfide structure.

[0035] In Example 1, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0036] Example 2

[0037] Li₂O, LiH, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 3:2:1:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li. 5.5 PS30 1.5 Cl 1.5 Solid electrolyte powder. Solid electrolyte powder is pressed at 300 MPa and held for 1 minute to obtain solid electrolyte tablets. Its XRD pattern is shown in the attached figure. Figure 1 As shown in the attached EIS diagram. Figure 2 As shown, the XRD diffraction peaks of the sulfide sample correspond to the standard diffraction card of Li7PS6 (PDF#34-0688), confirming the successful synthesis of a sulfide solid electrolyte with a sulfide-germanium sulfide structure. The ionic conductivity of this sample at room temperature is 2.53 × 10⁻⁶. -3 S / cm.

[0038] In Example 2, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0039] Example 3: Air stability test

[0040] Weigh 80 mg of Li obtained in Example 2 5.5 PS30 1.5 C1 1.5 A sulfide solid electrolyte was prepared by exposing the electrolyte powder to a sealed container at 30% RH for one hour at room temperature. The amount of H2S gas generated from the sample over time was measured using an H2S gas sensor. Simultaneously, XRD analysis was performed on the sample after air exposure. The XRD patterns are shown in the attached figure. Figure 1 As shown, the air stability test is as follows: Figure 5 As shown, after one hour of exposure to air, the XRD diffraction peaks of this sulfide solid electrolyte still correspond to the standard diffraction card of Li7PS6 (PDF#34-0688), with only a small amount of LiCl impurities produced. Furthermore, the electrolyte produced less H2S gas in the air stability test, demonstrating its good air stability.

[0041] Example 4

[0042] The electrolyte layer uses the electrolyte material obtained in Example 2, and an all-solid-state battery is prepared according to the following steps: (1) Weigh 0.60 g of Li(Ni) according to a mass ratio of 60:48:2. 0.8 Co 0.1 Mn 0.1 O2 material, 0.48 g of Li obtained in Example 2 5.5 PS30 1.5 C1 1.5 The sulfide solid electrolyte and 0.02 g VGCF were mechanically stirred for 10 min and then ground in a mortar for 10 min to obtain the composite cathode material. (2) Weigh 120 mg Li 5.5 PS30 1.5 C1 1.5 The sulfide solid electrolyte was placed in a solid battery mold with a diameter of 12 mm and spread evenly. Then it was pressed into a sheet with a pressure of 300~500 MPa and held for 60 s to obtain a solid electrolyte sheet. (3) Weigh 5 mg of the composite cathode material obtained in step 2) and place it into a solid-state battery mold. 5.5 PS30 1.5 C1 1.5 The sulfide solid electrolyte is evenly spread on one side, and then the composite cathode material and the double electrolyte layer are compacted under a pressure of 300~500 MPa and held for 60 s. (4) Attach a lithium sheet with a diameter of 10 mm and a thickness of 30 μm to the Li 5.5 PS30 1.5 C1 1.5 The other side of the sulfide solid electrolyte is then compacted with a pressure of 10 MPa to obtain an all-solid-state battery cell. (5) Finally, the formed solid-state battery cells are placed into a button cell casing for encapsulation to obtain an all-solid-state battery. The all-solid-state battery is then subjected to charge-discharge tests at 30°C and 0.1C. The first-cycle charge-discharge curve of the all-solid-state battery is shown in the attached figure. Figure 6 As shown in the attached figure, the cycle performance curves of the all-solid-state battery are as follows. Figure 7 As shown, its first-cycle discharge specific capacity can reach 192.5 mAh g. -1 After 100 cycles, its discharge specific capacity remains at 163.0 mAh g⁻¹. -1 .

[0043] In Example 4, the all-solid-state battery was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0044] Example 5

[0045] Li₂O, LiH, S, P₂S₅, and LiBr were weighed according to a molar ratio of 3:2:1:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. Vacuum was applied to the jar at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li. 5.5 PS30 1.5 Br 1.5 Solid electrolyte powder. Solid electrolyte powder is pressed at 300 MPa and held for 1 minute to obtain solid electrolyte sheets. Its EIS image is attached. Figure 3 As shown in the attached SEM image. Figure 8 As shown. The sample exhibits a high ionic conductivity of 1.92 × 10⁻⁶ at room temperature. -3 S / cm, SEM showed that the sample particles were about 10μm in size and had irregular shapes.

[0046] In Example 5, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0047] Example 6

[0048] Li₂O₂, LiH, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 3:2:1:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar and pestle for 20 minutes to obtain Li. 5.5 PS30 1.5 Cl 1.5 Solid electrolyte powder. Its SEM image is attached. Figure 9 As shown, SEM revealed that the sample particles were approximately 12 μm in size and exhibited irregular shapes.

[0049] In Example 6, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0050] Example 7

[0051] Li₂CO₃, LiH, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 3:2:1:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 550 r / min for 12 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li. 5.5 PS30 1.5 Cl 1.5 Solid electrolyte powder.

[0052] In Example 7, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0053] Example 8

[0054] Li3PO4, LiH, S, P2S5, and LiCl raw materials were weighed according to a molar ratio of 3:2:1:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 550 r / min for 12 hours. The ball mill jar was vacuumed at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li7P. 2.5 S3O6C1 1.5 Solid electrolyte powder.

[0055] In Example 8, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0056] Example 9

[0057] Li₂O, Li₃N, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 9:2:3:3:9 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. Vacuum was applied to the ball mill jar at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li. 7.5 PS30 1.5 C1 1.5 Solid electrolyte powder.

[0058] In Example 9, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0059] Example 10

[0060] Li₂O, LiNH₂, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 3:2:1:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar and pestle for 20 minutes to obtain Li. 5.5PS30 1.5 C1 1.5 Solid electrolyte powder.

[0061] In Example 10, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0062] Example 11

[0063] Li₂O, CH₃Li, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 3:2:2:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 450℃ at a rate of 1℃ / min, and held at this temperature for 4 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li. 5.5 PS30 1.5 C1 1.5 Solid electrolyte powder.

[0064] In Example 11, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0065] Example 12

[0066] Li₂O, C₆H₅Li, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 3:2:2:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. Subsequently, the solid electrolyte precursor was removed and placed in a constant-temperature heating mantle, heated to 550℃ at a rate of 1℃ / min, and held at that temperature for 4 hours. After natural cooling, it was ground in a mortar and pestle for 20 minutes to obtain Li. 5.5 PS30 1.5 C1 1.5 Solid electrolyte powder.

[0067] In Example 12, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0068] Example 13

[0069] Li₂O, LiH, thiourea, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 3:2:1:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li. 5.5 PS30 1.5 Cl 1.5 Solid electrolyte powder.

[0070] In Example 13, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0071] Example 14

[0072] Li₂O, LiH, S, P, and LiCl raw materials were weighed according to a molar ratio of 3:2:1:2:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was evacuated at the 3rd, 6th, 12th, and 24th hours. Subsequently, the solid electrolyte precursor was removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 2℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain Li. 5.5 PS 0.5 O 1.5 Cl 1.5 Solid electrolyte powder.

[0073] In Example 14, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0074] Example 15

[0075] Li₂O, LiH, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 1:6:3:1:3 and sequentially placed into a stainless steel ball mill jar equipped with a gas valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, the ball mill jar was sealed, and a vacuum was applied. The jar was then placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. The ball mill jar was vacuumed at the 3rd, 6th, 12th, and 24th hours. Subsequently, the solid electrolyte precursor was removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar and pestle for 20 minutes to obtain Li. 5.5 PS40 0.5 C1 1.5 Solid electrolyte powder.

[0076] In Example 15, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0077] Example 16

[0078] Li₂O, LiH, S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 4:0:0:1:3, with P₂S₅ providing the sulfur in the electrolyte. These raw materials were then sequentially placed into a stainless steel ball mill jar equipped with a gas valve, along with stainless steel balls at a ball-to-material ratio of 40:1. The jar was sealed and evacuated, then placed in a planetary ball mill for milling at 500 rpm for 24 hours. Vacuuming was performed on the jar at the 3rd, 6th, 12th, and 24th hours. The solid electrolyte precursor was then removed and placed in a constant-temperature heating mantle, heated to 490°C at a rate of 1°C / min, and held at that temperature for 2 hours. After natural cooling, it was ground in a mortar for 20 minutes to obtain LiCl. 5.5 PS 2.5 O2C1 1.5 Solid electrolyte powder.

[0079] In Example 16, the solid electrolyte was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0080] Comparative Example 1

[0081] LiH, S, P2S5, and LiCl raw materials were weighed according to a molar ratio of 8:4:1:3 and sequentially placed into a stainless steel ball mill jar without an air valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, and the jar was sealed before being placed in a planetary ball mill for milling at a ball speed of 500 r / min for 24 hours. Subsequently, the solid electrolyte precursor was removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 1℃ / min, and held at that temperature for 2 hours. After natural cooling, it was placed in a mortar and ground for 20 minutes to obtain Li. 5.5 PS4.5 C1 1.5 Solid electrolyte powder. Solid electrolyte powder is pressed at 300 MPa and held for 1 minute to obtain solid electrolyte tablets. Its XRD pattern is shown in the attached figure. Figure 1 As shown in the attached EIS diagram. Figure 4 As shown, the XRD diffraction peaks of the sulfide sample do not correspond to the standard diffraction card of Li7PS6 (PDF#34-0688), indicating the presence of numerous impurities such as P4S5, Li2S, and LiCl, proving that a sulfide solid electrolyte with a sulfide-germanium sulfide structure was not synthesized. The ionic conductivity of this sample at room temperature is 1.01 × 10⁻⁶. -8 The S / cm ratio indicates that simply replacing Li2S with LiH and S cannot successfully synthesize sulfide solid electrolytes of the sulfide type.

[0082] It can be seen that it is difficult to synthesize sulfide solid electrolytes by simply replacing lithium sulfide with existing lithium sulfide preparation methods. However, this invention, by creatively using lithium oxide to control the elements and their proportions in the electrolyte, successfully achieves the low-cost synthesis of sulfide solid electrolytes, which has extremely high creativity and excellent economic and market value.

[0083] The solid electrolyte in Comparative Example 1 was prepared under an argon atmosphere, where H2O < 0.01 ppm and O2 < 0.01 ppm.

[0084] Comparative Example 2

[0085] Li₂S, P₂S₅, and LiCl raw materials were weighed according to a molar ratio of 4:1:3 and placed sequentially into a stainless steel ball mill jar without a valve. Stainless steel balls with a ball-to-material ratio of 40:1 were added, and the jar was sealed before being placed in a planetary ball mill for milling at a ball speed of 500 r / min for 15 hours. Subsequently, the solid electrolyte precursor was removed and placed in a constant-temperature heating mantle, heated to 490℃ at a rate of 2℃ / min, and held at that temperature for 2 hours. After natural cooling, it was placed in a mortar and ground for 20 minutes to obtain Li. 5.5 PS 4.5 C1 1.5 Solid electrolyte powder. Weigh 80 mg of the Li obtained above. 5.5 PS 4.5 C1 1.5 For solid electrolytes, electrolyte powder was exposed to air humidity at 30% in a sealed container for one hour, and the amount of H2S gas generated from the sample over time was measured using an H2S gas sensor. Its air stability was tested as follows: Figure 5As shown, the electrolyte produced more H2S gas in the air stability test, proving its poorer air stability. The improvement in air stability in this application is mainly due to oxygen doping, which effectively suppresses the characteristic side reactions between sulfide electrolytes and moisture by forming stronger and more stable Li-O bonds, thereby reducing the generation of toxic H2S gas.

[0086] In summary, this invention, through the ingenious addition of lithium oxide, not only significantly reduces the economic cost of synthesizing silver sulfide-germanium sulfide solid electrolytes, but also improves the air stability of silver sulfide-germanium sulfide solid electrolytes, thus possessing extremely high market value.

[0087] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications may be made without departing from the technical solutions described in the claims.

Claims

1. A method for producing a argyrodite sulfide solid-state electrolyte, characterized by, The method comprises the following steps: (1) under an inert atmosphere, a lithium source 1, a lithium source 2, a sulfur source, a phosphorus source, LiX and ball milling beads are added into a ball milling jar, the ball milling jar is sealed and vacuumized, and then ball milling is performed to obtain a solid electrolyte precursor; the lithium source 1 is selected from one or more of Li2O, Li2O2, Li2CO3 and Li3PO4; the lithium source 2 is selected from one or more of LiH, Li3N, LiNH2, CH3Li and C6H5Li; (2) the solid electrolyte precursor is sintered under an inert atmosphere to obtain the argyrodite sulfide solid electrolyte.

2. The method for producing a argyrodite sulfide solid-state electrolyte according to claim 1, characterized by, In step (1), the molar ratio of the lithium source 1, the lithium source 2, the sulfur source, the phosphorus source and LiX is 5-0.2:0-7.6:0-3.8:1:1.5-3.

3. The method for producing argyrodite sulfide solid-state electrolyte according to claim 1, characterized by, In step (1), the sulfur source is selected from at least one of S and thiourea; the phosphorus source is selected from at least one of P2S5 and P; and in LiX, X is at least one of Cl, Br or I.

4. The method for producing argyrodite sulfide solid-state electrolyte according to claim 1, characterized by, In step (1), the ball-to-material ratio of the ball milling beads to the material is 10-60:1, the ball milling speed is 100-1200 rpm, and the ball milling time is 6-60 hours.

5. The method of producing a argyrodite sulfide solid state electrolyte according to claim 1, characterized by, In step (1), the sealed ball milling jar is vacuumized during the ball milling process.

6. The method of producing a argyrodite sulfide solid state electrolyte according to claim 1, characterized by, In step (2), the sintering is performed at a temperature increasing rate of 1-10 ℃ / min to a temperature of 300-600 ℃, and the temperature is maintained for 1-12 hours.

7. The method of producing argyrodite sulfide solid-state electrolyte according to claim 1, characterized by, In step (2), after sintering, natural cooling is performed to room temperature, and the sulfide solid electrolyte powder is obtained by grinding for 10-30 minutes.

8. A argyrodite sulfide solid-state electrolyte produced by the production method according to any one of claims 1 to 7, characterized in that, The argyrodite sulfide solid-state electrolyte Li 3.0~7.5 PS 0.5~4.9 O 0.1~2.5 X 0.6~1.5 wherein X is at least one of Cl, Br or I.

9. Application of the argyrodite sulfide solid electrolyte prepared by the preparation method of any one of claims 1-7 or the argyrodite sulfide solid electrolyte material of claim 8 in a full solid-state lithium battery.

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