A method for preparing a high-conductivity, high-yield sulfide solid-state electrolyte

Abstract

This invention discloses a method for preparing a high-conductivity, high-yield sulfide solid electrolyte, relating to the field of sulfide solid electrolytes. The method uses Li₂S and P₂S₅ as the main components, supplemented by conductive additives, and is prepared through processes including small-diameter ball milling media, high-speed mechanical processing, subsequent heat treatment, and pressing. The resulting material has fine particle size, forms a high-ionic-conductivity phase, and exhibits long cycle life and excellent full-cell cycle performance in lithium-ion symmetric batteries. This method has significant advantages such as simple process, low energy consumption, good film-forming properties, and suitability for industrial production.

Description

Technical Field

[0001] This invention relates to the field of sulfide solid electrolytes, and in particular to a method for preparing a sulfide solid electrolyte with high conductivity and high yield. Background Technology

[0002] Lithium-ion batteries using liquid electrolytes have been widely used in electronic devices, energy storage systems and electric vehicles, but they have many inherent defects, including safety hazards (liquid leakage, combustion risk), cycle life limitations and energy density bottlenecks, making it difficult to meet the future development needs for high safety, high energy density and long life.

[0003] Therefore, inorganic solid electrolytes—especially sulfide solid electrolytes—have become one of the core research directions for all-solid-state batteries due to their characteristics such as "safety," "high conductivity," and "superior mechanical properties." Compared with oxide or polymer electrolytes, sulfides can provide higher ionic conductivity, while having a relatively low Young's modulus, which improves interfacial compaction and ease of manufacturing processes.

[0004] Typical sulfide systems such as Li₂S–P₂S₅ (Li–P–S system) possess excellent structural flexibility and ion conduction pathways, making them suitable for preparing electrolytes with high ionic conductivity. Furthermore, doping with halogens (such as Cl, Br, I) or other components (such as Ge, B, etc.) can further enhance conductivity and chemical stability. For example, patent US2021 / 0104774A1 proposes adding halogen elements to the Li₂S–P₂S₅-based system to significantly improve ionic conductivity, with the preferred molar ratio of Li₂S to P₂S₅ being between 70 and 80 mol%, particularly recommended to be 74 to 76 mol%, to ensure the material composition is close to an orthorhombic structure and improve chemical stability.

[0005] Currently, the main technical routes for preparing sulfide solid electrolytes are high-temperature melt quenching, mechanical ball milling (solid-phase method), liquid-phase synthesis, and gas-phase method. Mechanical ball milling is widely used due to its simplicity, short preparation cycle, and suitability for large-scale production. For example, Japanese Patent JP2009-277383 describes the preparation of a Li2S–P2S5 system solid electrolyte and emphasizes that a mechanical method can yield electrolytes with low electronic conductivity (approximately 2 × 10⁻⁶). -9 Solid electrolytes (S / cm) that suppress battery self-discharge.

[0006] On the other hand, the solid-phase method has a complicated operation process and consumes a lot of energy; although the liquid-phase method can improve the mixing uniformity, it is limited by poorly soluble raw materials (such as Li2S and P2S5), the preparation process is complicated, porous structures are easily generated during film formation, and the overall cost is high.

[0007] JP2009-277383A (Japanese Patent Document 1): Proposes Li2S and P2S5 series solid electrolytes, emphasizing their "low electronic conductivity" to suppress the self-discharge problem of all-solid-state lithium batteries.

[0008] US20210104774A1 (US Patent Document): Adding halogens (such as LiI, LiBr, LiCl, etc.) or oxides to the Li2S–P2S5 basic system to improve conductivity, and preferably the molar ratio of Li2S in the total components is 70~80 mol.

[0009] US9356315B2 (US Patent Document): Provides a sulfide electrolyte and its application in lithium solid-state batteries. It cites mechanical synthesis literature (such as Hayashi et al.'s research on synthesizing Li2S amorphous electrolyte by mechanical crushing) as the technical basis, and points out that mechanical synthesis is suitable for integrating high-performance sulfide electrolytes.

[0010] In summary, sulfide solid electrolytes currently possess inherent advantages over traditional liquid electrolytes in terms of ionic conductivity, safety, and processing performance. Furthermore, mainstream compositions such as the Li₂S–P₂S₅ system can have their performance further enhanced through structural optimization (e.g., halogen doping). While mechanical ball milling is the primary preparation method, it still faces challenges related to cost, structural control, and industrialization compared to solid-phase and liquid-phase methods. Summary of the Invention

[0011] To overcome the shortcomings of existing technologies, this invention provides a method for preparing a highly conductive, high-yield sulfide solid electrolyte. An improved ball milling process and dry thin-film molding are utilized, and boron doping is used to enhance material properties. The resulting solid electrolyte exhibits high ionic conductivity.

[0012] The specific plan is as follows: A method for preparing a highly conductive, high-yield sulfide solid electrolyte includes the following steps: Raw material ratio: Mix 70-75 parts by mass of Li2S and 25-30 parts by mass of P2S5, and add 5-30 parts by mass of ionic conductivity promoter, 0.1-5 parts by mass of B2S3 dopant and 2-8 parts by mass of modified conductivity promoter. Mixing and ball milling: In an inert gas environment, place the above raw materials and ball milling media together in a ball milling jar, add 80-125 parts by weight of solvent, and perform high-energy ball milling; Solvent removal: Vacuum drying or rotary evaporation is used, and the solution is treated at 80–180°C for 2–12 hours. Heat treatment: The dried powder is placed in an inert gas protective environment for heat treatment at a temperature of 200-500℃ for 1-12 hours. Compression molding: The obtained electrolyte powder is formed by hot pressing into thin sheets or blocks with a thickness controlled between 50 and 300 μm.

[0013] In some embodiments, the conductivity promoter is selected from LiBr or LiCl.

[0014] In some embodiments, the method for preparing the modified conductivity promoter is as follows: Raw material ratio: By weight, mix 100 parts of the basic conductivity promoter lithium methacrylate (CAS: 13234-23-6), 0.5-3 parts of the modifier 1,1,3,3-tetramethyldisiloxane (CAS: 3277-26-7), and 1000-1200 parts of the solvent anhydrous tetrahydrofuran, and add 0.1-0.5 parts of the catalyst chloroplatinic acid; Hydrosilylation reaction: Under the protection of inert gas Ar or N2, heat to 60-80℃ and stir for 4-8 hours; Post-processing: After the reaction is completed, cool to 20-30℃, add 10-20 parts of anhydrous ethanol to demulsify, filter under reduced pressure, dry the filter cake under vacuum at 50-70℃ for 6-10 hours at a pressure of 10-20 mbar, and pulverize through a 100-200 mesh sieve to obtain the modified conductivity promoter.

[0015] In some embodiments, the pressure reduction filtration parameters are: pressure 50-150 mbar, temperature 20-25℃, PTFE filter membrane, pore size 1-5 μm.

[0016] In some embodiments, the inert gas is selected from Ar or N2.

[0017] In some embodiments, the milling media are zirconia beads with a diameter of 0.2 mm to 10 mm.

[0018] In some embodiments, the solvent is selected from tetrahydrofuran, acetonitrile, n-heptane, or toluene.

[0019] In some embodiments, the high-energy ball milling parameters are: rotation speed 400-1000 rpm, duration 0.5-20 hours.

[0020] In some embodiments, the heating rate of the heat treatment is 1 to 5 °C / min.

[0021] In some embodiments, the hot pressing molding parameters are: pressure of 100-400 MPa and temperature of 100-200°C.

[0022] I. Modified reaction mechanism (synergistic mechanism of hydrosilylation and impurity adsorption) Under the catalysis of chloroplatinic acid, the Si-H bonds in 1,1,3,3-tetramethyldisiloxane are activated, undergoing an electrophilic addition reaction with the carbon-carbon double bonds on the lithium methacrylate molecular chain to form stable Si-C covalent bonds, successfully grafting the siloxane structure onto the lithium salt molecular chain. This reaction produces no small molecule byproducts, avoiding the introduction of additional impurities that could affect electrolyte purity. Simultaneously, the lone pair electrons of the oxygen atom in the siloxane structure can form coordinate bonds with the P atoms of any residual P2S5 in the raw material, fixing the residual P2S5 through chemisorption and reducing its influence on Li. + Transport is hindered; however, the main structure of lithium methacrylate is preserved, maintaining the Li + The integrity of the conduction channel, in turn, provides support for the ion transport performance and stability of the electrolyte from the aspects of "structural optimization" and "impurity control".

[0023] II. Technical Effects After Modification Significantly improving ionic conductivity can be achieved by optimizing the basic ratio of Li₂S to P₂S₅, introducing halogen-based conductivity promoters and B₂S₃ dopants, which can promote the formation of high ionic conductivity phases. Simultaneously, the grafting structure of the modified conductivity promoters can optimize the Li₂S / P₂S₅ phase. + The transport path is improved, transport resistance is reduced, and the ionic conductivity of the electrolyte is enhanced synergistically.

[0024] Incorporating halogens and B2S3 into sulfide electrolyte systems can enhance the stability of the crystal structure, thereby improving chemical and electrochemical stability. The siloxane structure in the modifier can modify the electrode-electrolyte interface, reducing the corrosion of the electrolyte by air or liquid electrode components, while expanding the electrochemical window, reducing the probability of interfacial side reactions, and improving the stability of the electrolyte in long-term use.

[0025] When the sulfide electrolyte prepared to optimize the performance of the full cell is applied to the all-solid-state battery, it can effectively reduce the interfacial impedance between the electrode and the electrolyte and reduce capacity decay during cycling. At the same time, it can improve the rate adaptability of the battery, ensure good performance at different charge and discharge rates, and help improve the first-cycle coulombic efficiency and extend the overall cycle life of the battery. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.

[0027] Example 1 A method for preparing a highly conductive, high-yield sulfide solid electrolyte includes the following steps: Raw material ratio: Mix 70g Li2S and 30g P2S5, add 5g conductivity promoter, 0.1g B2S3 dopant and 2g modified conductivity promoter; the conductivity promoter is LiBr.

[0028] Mixing and ball milling: In an Ar inert gas environment, the above raw materials and ball milling media were placed together in a ball milling jar, and 80g of tetrahydrofuran solvent was added for high-energy ball milling; the ball milling media were zirconia beads with a diameter of 0.2mm; the high-energy ball milling parameters were: rotation speed 400rpm, duration 0.5 hours.

[0029] Solvent removal: Vacuum drying was performed, followed by treatment at 80°C for 2 hours.

[0030] Heat treatment: The dried powder was placed in an Ar inert gas protective environment for heat treatment at a temperature of 200℃ for 1 hour, with a heating rate of 1℃ / min.

[0031] Compression molding: The obtained electrolyte powder is formed by hot pressing into thin sheets with a thickness controlled at 50 μm; the hot pressing molding parameters are: pressure of 100 MPa and temperature of 100 °C.

[0032] The preparation method of the modified conductivity promoter: Raw material ratio: Mix 100g lithium methacrylate (CAS: 13234-23-6), 0.5g modifier 1,1,3,3-tetramethyldisiloxane (CAS: 3277-26-7), 1000g solvent anhydrous tetrahydrofuran, and add 0.1g catalyst chloroplatinic acid.

[0033] Hydrosilylation reaction: Under Ar inert gas protection, the temperature was raised to 60°C and the reaction was stirred for 4 hours.

[0034] Post-processing: After the reaction was completed, the temperature was lowered to 20°C, 10g of anhydrous ethanol was added to break the emulsion, and the mixture was filtered under reduced pressure. The filter cake was dried under vacuum at 50°C for 6 hours at a pressure of 10mbar, and then pulverized through a 100-mesh sieve to obtain the modified conductive promoter. The reduced pressure filtration parameters were: pressure 50mbar, temperature 20°C, PTFE filter membrane, and pore size 1μm.

[0035] Example 2 A method for preparing a highly conductive, high-yield sulfide solid electrolyte includes the following steps: Raw material ratio: Mix 71.5g Li2S and 28.5g P2S5, add 12g conductivity promoter, 1.5g B2S3 dopant and 4g modified conductivity promoter; the conductivity promoter is LiCl.

[0036] Mixing and ball milling: In an inert N2 gas environment, the above raw materials and ball milling media are placed together in a ball milling jar, and 95g of solvent acetonitrile is added for high-energy ball milling; the ball milling media are zirconia beads with a diameter of 3mm; the high-energy ball milling parameters are: rotation speed 600rpm, duration 6 hours.

[0037] Solvent removal: Rotary evaporation was used, and the solution was treated at 110°C for 5 hours.

[0038] Heat treatment: The dried powder is placed in an N2 inert gas protective environment for heat treatment at a temperature of 300℃ for 5 hours, with a heating rate of 2℃ / min.

[0039] Compression molding: The obtained electrolyte powder is formed by hot pressing into thin sheets with a thickness controlled at 120μm; the hot pressing molding parameters are: pressure of 200MPa and temperature of 130℃.

[0040] The preparation method of the modified conductivity promoter: Raw material ratio: Mix 100g lithium methacrylate (CAS: 13234-23-6), 1.5g modifier 1,1,3,3-tetramethyldisiloxane (CAS: 3277-26-7), 1100g solvent anhydrous tetrahydrofuran, and add 0.25g catalyst chloroplatinic acid.

[0041] Hydrosilylation reaction: Under the protection of N2 inert gas, the temperature was raised to 65°C and the reaction was stirred for 5 hours.

[0042] Post-processing: After the reaction was completed, the temperature was lowered to 23°C, 14g of anhydrous ethanol was added to break the emulsion, and the mixture was filtered under reduced pressure. The filter cake was dried under vacuum at 55°C for 7 hours at a pressure of 14mbar, and then pulverized through a 140-mesh sieve to obtain the modified conductive accelerator. The reduced pressure filtration parameters were: pressure 80mbar, temperature 22°C, PTFE filter membrane, and pore size 2μm.

[0043] Example 3 A method for preparing a highly conductive, high-yield sulfide solid electrolyte includes the following steps: Raw material ratio: Mix 73.5g Li2S and 26.5g P2S5, add 22g conductivity promoter, 3.5g B2S3 dopant and 6g modified conductivity promoter; the conductivity promoter is LiBr.

[0044] Mixing and ball milling: In an Ar inert gas environment, the above raw materials and ball milling media were placed together in a ball milling jar, and 105g of solvent n-heptane was added for high-energy ball milling; the ball milling media were zirconia beads with a diameter of 7mm; the high-energy ball milling parameters were: rotation speed 800rpm, duration 13 hours.

[0045] Solvent removal: Vacuum drying was performed, followed by treatment at 150°C for 9 hours.

[0046] Heat treatment: The dried powder was placed in an Ar inert gas protective environment for heat treatment at a temperature of 400℃ for 9 hours, with a heating rate of 4℃ / min.

[0047] Compression molding: The obtained electrolyte powder is formed into a block by hot pressing, with the thickness controlled at 220μm; the hot pressing molding parameters are: pressure of 300MPa and temperature of 170℃.

[0048] The preparation method of the modified conductivity promoter: Raw material ratio: Mix 100g lithium methacrylate (CAS: 13234-23-6), 2.5g modifier 1,1,3,3-tetramethyldisiloxane (CAS: 3277-26-7), 1100g solvent anhydrous tetrahydrofuran, and add 0.4g catalyst chloroplatinic acid.

[0049] Hydrosilylation reaction: Under Ar inert gas protection, the temperature was raised to 75°C and the reaction was stirred for 7 hours.

[0050] Post-processing: After the reaction was completed, the temperature was lowered to 27°C, 18g of anhydrous ethanol was added to break the emulsion, and the mixture was filtered under reduced pressure. The filter cake was dried under vacuum at 65°C for 9 hours at a pressure of 18mbar, and then pulverized through a 180-mesh sieve to obtain the modified conductive promoter. The reduced pressure filtration parameters were: pressure 120mbar, temperature 24°C, PTFE filter membrane, and pore size 4μm.

[0051] Example 4 A method for preparing a highly conductive, high-yield sulfide solid electrolyte includes the following steps: Raw material ratio: Mix 75g Li2S and 25g P2S5, add 30g conductivity promoter, 5g B2S3 dopant and 8g modified conductivity promoter; the conductivity promoter is LiCl.

[0052] Mixing and ball milling: In an inert N2 gas environment, the above raw materials and ball milling media are placed together in a ball milling jar, and 125g of solvent toluene is added for high-energy ball milling; the ball milling media are zirconia beads with a diameter of 10mm; the high-energy ball milling parameters are: rotation speed 1000rpm, duration 20 hours.

[0053] Solvent removal: Rotary evaporation was used, and the solution was treated at 180°C for 12 hours.

[0054] Heat treatment: The dried powder is placed in an inert gas environment of N2 for heat treatment at a temperature of 500℃ for 12 hours, with a heating rate of 5℃ / min.

[0055] Compression molding: The obtained electrolyte powder is formed into a block by hot pressing, with the thickness controlled at 300μm; the hot pressing molding parameters are: pressure of 400MPa and temperature of 200℃.

[0056] The preparation method of the modified conductivity promoter: Raw material ratio: Mix 100g lithium methacrylate (CAS: 13234-23-6), 3g modifier 1,1,3,3-tetramethyldisiloxane (CAS: 3277-26-7), 1200g solvent anhydrous tetrahydrofuran, and add 0.5g catalyst chloroplatinic acid.

[0057] Hydrosilylation reaction: Under the protection of N2 inert gas, the temperature was raised to 80℃ and the reaction was stirred for 8 hours.

[0058] Post-processing: After the reaction was completed, the temperature was lowered to 30°C, 20g of anhydrous ethanol was added to break the emulsion, and the mixture was filtered under reduced pressure. The filter cake was vacuum dried at 70°C for 10 hours at a pressure of 20mbar, and then pulverized through a 200-mesh sieve to obtain the modified conductive accelerator. The reduced pressure filtration parameters were: pressure 150mbar, temperature 25°C, PTFE filter membrane, and pore size 5μm.

[0059] Comparative Example 1 A method for preparing a highly conductive, high-yield sulfide solid electrolyte includes the following steps: Raw material ratio: Mix 70g Li2S and 30g P2S5, add 5g conductivity promoter and 0.1g B2S3 dopant; the conductivity promoter is LiBr.

[0060] Mixing and ball milling: In an Ar inert gas environment, the above raw materials and ball milling media were placed together in a ball milling jar, and 80g of tetrahydrofuran solvent was added for high-energy ball milling; the ball milling media were zirconia beads with a diameter of 0.2mm; the high-energy ball milling parameters were: rotation speed 400rpm, duration 0.5 hours.

[0061] Solvent removal: Vacuum drying was performed, followed by treatment at 80°C for 2 hours.

[0062] Heat treatment: The dried powder was placed in an Ar inert gas protective environment for heat treatment at a temperature of 200℃ for 1 hour, with a heating rate of 1℃ / min.

[0063] Compression molding: The obtained electrolyte powder is formed by hot pressing into thin sheets with a thickness controlled at 50 μm; the hot pressing molding parameters are: pressure of 100 MPa and temperature of 100 °C.

[0064] Comparative Example 2 A method for preparing a highly conductive, high-yield sulfide solid electrolyte includes the following steps: Raw material ratio: Mix 70g Li2S and 30g P2S5, add 5g conductivity promoter, 0.1g B2S3 dopant and 2g modified conductivity promoter; the conductivity promoter is LiBr.

[0065] Mixing and ball milling: In an Ar inert gas environment, the above raw materials and ball milling media were placed together in a ball milling jar, and 80g of tetrahydrofuran solvent was added for high-energy ball milling; the ball milling media were zirconia beads with a diameter of 0.2mm; the high-energy ball milling parameters were: rotation speed 400rpm, duration 0.5 hours.

[0066] Solvent removal: Vacuum drying was performed, followed by treatment at 80°C for 2 hours.

[0067] Heat treatment: The dried powder was placed in an Ar inert gas protective environment for heat treatment at a temperature of 200℃ for 1 hour, with a heating rate of 1℃ / min.

[0068] Compression molding: The obtained electrolyte powder is formed by hot pressing into thin sheets with a thickness controlled at 50 μm; the hot pressing molding parameters are: pressure of 100 MPa and temperature of 100 °C.

[0069] The preparation method of the modified conductivity promoter: Raw material ratio: Mix 100g lithium methacrylate (CAS: 13234-23-6) and 1000g anhydrous tetrahydrofuran solvent, and add 0.1g chloroplatinic acid catalyst.

[0070] Hydrosilylation reaction: Under Ar inert gas protection, the temperature was raised to 60°C and the reaction was stirred for 4 hours.

[0071] Post-processing: After the reaction was completed, the temperature was lowered to 20°C, 10g of anhydrous ethanol was added to break the emulsion, and the mixture was filtered under reduced pressure. The filter cake was dried under vacuum at 50°C for 6 hours at a pressure of 10mbar, and then pulverized through a 100-mesh sieve to obtain the modified conductive promoter. The reduced pressure filtration parameters were: pressure 50mbar, temperature 20°C, PTFE filter membrane, and pore size 1μm.

[0072] Comparative Example 3 A method for preparing a highly conductive, high-yield sulfide solid electrolyte includes the following steps: Raw material ratio: Mix 70g Li2S and 30g P2S5, add 5g conductivity promoter, 0.1g B2S3 dopant and 2g modified conductivity promoter; the conductivity promoter is LiBr.

[0073] Mixing and ball milling: In an Ar inert gas environment, the above raw materials and ball milling media were placed together in a ball milling jar, and 80g of tetrahydrofuran solvent was added for high-energy ball milling; the ball milling media were zirconia beads with a diameter of 0.2mm; the high-energy ball milling parameters were: rotation speed 400rpm, duration 0.5 hours.

[0074] Solvent removal: Vacuum drying was performed, followed by treatment at 80°C for 2 hours.

[0075] Heat treatment: The dried powder was placed in an Ar inert gas protective environment for heat treatment at a temperature of 200℃ for 1 hour, with a heating rate of 1℃ / min.

[0076] Compression molding: The obtained electrolyte powder is formed by hot pressing into thin sheets with a thickness controlled at 50 μm; the hot pressing molding parameters are: pressure of 100 MPa and temperature of 100 °C.

[0077] The preparation method of the modified conductivity promoter: Raw material ratio: Mix 0.5g of modifier 1,1,3,3-tetramethyldisiloxane (CAS: 3277-26-7) and 1000g of solvent anhydrous tetrahydrofuran, and add 0.1g of catalyst chloroplatinic acid.

[0078] Hydrosilylation reaction: Under Ar inert gas protection, the temperature was raised to 60°C and the reaction was stirred for 4 hours.

[0079] Post-processing: After the reaction was completed, the temperature was lowered to 20°C, 10g of anhydrous ethanol was added to break the emulsion, and the mixture was filtered under reduced pressure. The filter cake was dried under vacuum at 50°C for 6 hours at a pressure of 10mbar, and then pulverized through a 100-mesh sieve to obtain the modified conductive promoter. The reduced pressure filtration parameters were: pressure 50mbar, temperature 20°C, PTFE filter membrane, and pore size 1μm.

[0080] The testing method involved in this invention is as follows: 1) Electro-acoustic impedance (EIS) measurement and conductivity calculation The disc was sandwiched between two stainless steel blocking electrodes in a constant temperature chamber (25.0±0.1℃). The volume resistance Rb at the high frequency was measured using an impedance analyzer (frequency range 1MHz→0.1Hz, AC amplitude 10mV rms).

[0081] Calculate: σ = L / (R·A).

[0082] 2) Cyclic performance of the full cell (cathode-NMC system) Assemble NMC|SE|Li graphite anode full cells and cycle them 200 times at 0.1C and 0.5C at 25℃. Record the first cycle discharge specific capacity, first cycle coulombic efficiency, and capacity retention.

[0083] Table 1 Test Results

[0084] As can be seen from the test results in Table 1, the examples (1-4) prepared by the present invention are significantly superior to the comparative examples (1-3) in terms of room temperature ionic conductivity, first-cycle discharge specific capacity of the full cell, first-cycle coulombic efficiency, and 200-cycle capacity retention. Comparative Example 1, due to the absence of modified conductivity promoters, exhibited low ionic conductivity and low battery cycle performance. The modified conductivity promoter of Comparative Example 2 lacked 1,1,3,3-tetramethyldisiloxane (modifier) ​​during preparation, which prevented the formation of an effective graft structure, resulting in lower conductivity and capacity retention than in the example. The modified conductivity promoter in Comparative Example 3 lacked lithium methacrylate (the basic conductivity promoter) during its preparation, making it difficult to maintain Li + The conduction pathway exhibits performance close to that of Comparative Example 1 without added additives.

[0085] In summary, the embodiments effectively solved the performance shortcomings caused by component deficiency or structural defects in the comparative examples through the synergistic solution of "basic component optimization + introduction of modified conductivity promoters", fully demonstrating the effectiveness of the preparation method of the present invention in improving the overall performance of sulfide solid electrolytes.

[0086] Although specific embodiments of the invention have been described in detail, variations of these embodiments can be implemented by those skilled in the art. Furthermore, as set forth in the appended claims, such variations can be obtained without departing from the true spirit and scope of the invention.

Claims

1. A method for preparing a highly conductive, high-yield sulfide solid electrolyte, characterized in that, Includes the following steps: Raw material ratio: 70-75 parts by weight of Li2S and 25-30 parts by weight of P2S5 are mixed, and 5-30 parts by weight of conductivity promoter, 0.1-5 parts by weight of B2S3 dopant and 2-8 parts by weight of modified conductivity promoter are added. Mixing and ball milling: In an inert gas environment, place the above raw materials and ball milling media together in a ball milling jar, add 80-125 parts by weight of solvent, and perform high-energy ball milling; Solvent removal: Vacuum drying or rotary evaporation is used, and the solution is treated at 80–180°C for 2–12 hours. Heat treatment: The dried powder is placed in an inert gas protective environment for heat treatment at a temperature of 200-500℃ for 1-12 hours. Compression molding: The obtained electrolyte powder is formed by hot pressing into thin sheets or blocks with a thickness controlled between 50 and 300 μm; The modified conductivity promoter is prepared by a hydrosilylation reaction of lithium methacrylate and 1,1,3,3-tetramethyldisiloxane under chloroplatinic acid catalysis.

2. The method for preparing a high-conductivity, high-yield sulfide solid electrolyte according to claim 1, characterized in that: The conductivity promoter is selected from LiBr or LiCl.

3. The method for preparing a highly conductive, high-yield sulfide solid electrolyte according to claim 1, characterized in that: The preparation method of the modified conductivity promoter: Raw material ratio: By weight, mix 100 parts of the basic conductivity promoter lithium methacrylate, 0.5-3 parts of the modifier 1,1,3,3-tetramethyldisiloxane, and 1000-1200 parts of the solvent anhydrous tetrahydrofuran, and add 0.1-0.5 parts of the catalyst chloroplatinic acid; Hydrosilylation reaction: Under the protection of inert gas Ar or N2, heat to 60-80℃ and stir for 4-8 hours; Post-processing: After the reaction is completed, cool to 20-30℃, add 10-20 parts of anhydrous ethanol to demulsify, filter under reduced pressure, dry the filter cake under vacuum at 50-70℃ for 6-10 hours at a pressure of 10-20 mbar, and pulverize through a 100-200 mesh sieve to obtain the modified conductivity promoter.

4. The method for preparing a high-conductivity, high-yield sulfide solid electrolyte according to claim 3, characterized in that: The pressure reduction filtration parameters are: pressure 50-150 mbar, temperature 20-25℃, PTFE filter membrane, pore size 1-5 μm.

5. The method for preparing a high-conductivity, high-yield sulfide solid electrolyte according to claim 1, characterized in that: The inert gas is selected from Ar or N2.

6. The method for preparing a high-conductivity, high-yield sulfide solid electrolyte according to claim 1, characterized in that: The grinding media are zirconia beads with a diameter of 0.2 mm to 10 mm.

7. The method for preparing a high-conductivity, high-yield sulfide solid electrolyte according to claim 1, characterized in that: The solvent is selected from tetrahydrofuran, acetonitrile, n-heptane, or toluene.

8. The method for preparing a high-conductivity, high-yield sulfide solid electrolyte according to claim 1, characterized in that: The high-energy ball milling parameters are: rotation speed 400-1000 rpm, duration 0.5-20 hours.

9. The method for preparing a high-conductivity, high-yield sulfide solid electrolyte according to claim 1, characterized in that: The heating rate for the heat treatment is 1–5 °C / min.

10. The method for preparing a highly conductive, high-yield sulfide solid electrolyte according to claim 1, characterized in that: The hot pressing molding parameters are: pressure of 100-400 MPa and temperature of 100-200℃.

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