A method and application for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes.

Abstract

This invention discloses a method and application for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes, relating to the field of solid-state battery technology. The method includes: mixing sulfide solid electrolyte powder with a low electron-donating, low-hygroscopic solvent to form a wet grinding slurry under an inert atmosphere, followed by wet refining; storing or transporting the refined sulfide solid electrolyte in a solvent-containing wet form; and introducing the wet sulfide solid electrolyte into the slurry system for use, followed by dispersion treatment to obtain a uniformly dispersed sulfide solid electrolyte slurry. This invention effectively solves the problems of easy agglomeration and moisture absorption failure of sulfide electrolytes during grinding, storage, transportation, and use, and is particularly suitable for high-performance all-solid-state battery fields with stringent requirements for electrolyte particle size and dispersibility.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, and more specifically, to a method and application for grinding, wet storage and transportation, and redispersing of a sulfide solid electrolyte. Background Technology

[0002] Sulfide solid electrolytes possess high room-temperature ionic conductivity and good compactability, making them one of the most promising electrolyte materials for the industrialization of all-solid-state lithium batteries. However, these materials are extremely sensitive to water and oxygen. The smaller the particle size and the higher the specific surface area, the more prone they are to water absorption and degradation during processing, packaging, transportation, and opening at the application stage, leading to H2S release, surface by-product formation, and a decrease in ionic conductivity. Currently, supply is mainly in the form of dry powder delivery, which places extremely stringent requirements on packaging sealing and transportation environment. Even minor air leakage in the packaging or insufficient on-site drying conditions can lead to irreversible degradation of material performance.

[0003] To meet the requirements for preparing positive electrode composite electrodes and electrolyte membranes, sulfide electrolytes typically require wet refining. Traditional low-polarity solvents (such as alkanes and aromatics) have low reactivity with sulfides, but their wettability and dielectric shielding ability are insufficient, leading to soft sticking, cold welding, and re-agglomeration during the grinding process. This results in a wide particle size distribution in the obtained powder, leading to poor dispersion consistency in the subsequent slurry. While stronger solvents or dispersants such as esters and ethers can improve refining efficiency and slurry stability, their high electron-donating ability makes them prone to reacting with the Li₂ on the sulfide surface. + Interactions between sulfur sites or defects trigger grain boundary reconstruction, residual adsorption, and obstruction of ion migration channels, ultimately leading to a decrease in conductivity. Currently, wet grinding is often treated as an independent step, with drying, packaging, and transportation immediately following grinding. This approach fails to adequately address the need for waterproofing during storage and transportation, the formation of hard agglomerates during drying, and the requirement for secondary deagglomeration during pulping. Therefore, existing methods struggle to simultaneously achieve low-damage refining, long-term storage and transportation stability, and efficient redispersion, making it difficult to meet the requirements for large-scale delivery of sulfide electrolytes and downstream continuous pulping applications.

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

[0005] To address the technical challenge of simultaneously achieving particle size control, structural stability, and redispersibility in the wet refining, storage, transportation, and subsequent slurry preparation of sulfide solid electrolytes, this invention provides a method and application for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes. This application no longer simply views wet grinding as a single process for obtaining final dried nanoparticles, but rather synergistically designs grinding, wet storage, and subsequent redispersibility. Using a solvent system with low electron-donating capacity, low hygroscopicity, and easy removal, low-damage, reversible soft agglomerates of sulfide electrolyte particles are formed during the grinding stage. This solvent is then used to provide water-proof protection for the material during storage and transportation, ultimately achieving secondary deagglomeration and uniform dispersion during subsequent slurry preparation.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a method for grinding, wet storage and transportation, and redispersing a sulfide solid electrolyte, comprising the following steps: Under an inert atmosphere, sulfide solid electrolyte powder and a low DN-low hygroscopic solvent are mixed to form a wet grinding slurry, and the slurry is then subjected to wet refining treatment. The refined sulfide solid electrolyte is stored or transported in a wet form containing solvent; In use, the solvent-containing wet sulfide solid electrolyte is introduced into the slurry system, and the reversible soft agglomerates are dispersed to undergo secondary depolymerization, resulting in a uniformly dispersed sulfide solid electrolyte slurry.

[0007] In an optional embodiment, the low-DN, low-hygroscopic solvent has an electron-donating number ≤ 10 kcal / mol; the dielectric constant of the solvent is 2-10. And / or, the low DN-low hygroscopic solvent is selected from at least one of hydrofluoroethers, fluorinated aromatic hydrocarbons, low water-absorbing alkanes, or siloxanes.

[0008] In an optional embodiment, the low DN-low hygroscopic solvent is selected from at least one of trifluorotoluene, methyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, ethoxy nonafluorobutyl ether, fluorotoluene, n-nonane, n-heptane, isoalkanes, or hexamethyldisiloxane.

[0009] In an optional embodiment, the low DN-low hygroscopic solvent needs to be dehydrated and deoxygenated before use; And / or, the water content in the solvent is ≤500ppm.

[0010] In an optional embodiment, the solid content of the wet grinding slurry is 10-50 wt%.

[0011] In an optional embodiment, the wet refining process employs at least one of sand milling, ball milling, acoustic resonance mixing, high shear dispersion, or planetary mixing.

[0012] In an optional embodiment, the solvent content in the solvent-containing wet sulfide solid electrolyte is 5-80 wt%.

[0013] In an optional embodiment, the wet sulfide solid electrolyte is stored or transported in a sealed container, aluminum-plastic composite bag, metal can, or solvent-resistant packaging container.

[0014] In an optional embodiment, the solvent-containing wet sulfide solid electrolyte further includes a low-temperature vacuum drying process before being introduced into the slurry system; And / or, the drying temperature is <120°C.

[0015] In an optional embodiment, the slurry system includes one or more of a binder, a conductive agent, a positive electrode active material, or a film-forming polymer; And / or, the adhesive comprises one or more of PVDF, SEBS, SBS, PTFE, or PEO; And / or, the conductive agent includes one or more of conductive carbon black, carbon nanotubes, carbon nanofibers, or graphene.

[0016] In an optional embodiment, the D50 of the dispersed sulfide solid electrolyte particles is ≤1.5 μm.

[0017] In a second aspect, the present invention provides a wet sulfide solid electrolyte composition, the composition comprising sulfide solid electrolyte particles and a low DN-low hygroscopic organic solvent; the sulfide solid electrolyte particles are in a reversible soft agglomeration state.

[0018] In an optional embodiment, after the composition is stored in a sealed container for 30 days, the ionic conductivity of the dried sulfide solid electrolyte powder is maintained at no less than 80%.

[0019] Thirdly, the present invention provides a sulfide solid electrolyte slurry, which is prepared by the above method, or obtained by depolymerization and dispersion of the above wet sulfide solid electrolyte composition.

[0020] Fourthly, the present invention provides an all-solid-state battery in which the positive electrode or electrolyte film is formed using the above-mentioned sulfide solid electrolyte slurry.

[0021] The present invention has the following beneficial effects: (1) In the wet refining stage of this invention, the low DN-low hygroscopic solvent can form a wetting protective environment on the particle surface, reducing the chance of the powder coming into contact with external moisture, reducing the risk of water absorption and deterioration, and helping to inhibit the release of H2S and the formation of surface by-products. It avoids the use of high electron-donating polar solvents or high-boiling-point dispersants such as esters, strong ethers, nitriles, and sulfoxides, and reduces the effect of solvent molecules on the Li on the sulfide surface. + The disturbance of the site, defect sulfur site and grain boundary structure can maintain high ionic conductivity while reducing the grain size.

[0022] (2) This invention presents the sulfide electrolyte in a solvent-containing wet state, eliminating the need for forced complete drying and prolonged dry exposure, thereby effectively reducing hard agglomeration and irreversible particle bridging caused by drying shrinkage. In subsequent processing, it can be used after low-temperature vacuum drying or directly introduced into a compatible slurry system according to process requirements. The soft agglomerates are deagglomerated and uniformly dispersed through shear mixing, so that the final dispersion state of the material no longer depends on the grinding stage to be completed in one go, but is gradually achieved through a synergistic process of "pre-refining - wet protection - slurry redispersion". This method is beneficial to improving the structural stability and performance consistency of the sulfide electrolyte at each stage, and significantly improving the redispersion ability and performance of fine powder materials after long-term storage.

[0023] (3) The electrolyte particles of the present invention can maintain good intrinsic ion conduction characteristics and interface integrity, and can form a continuous ion transport network in the subsequent electrode or electrolyte layer preparation process. They are suitable for all-solid-state battery positive electrode composite layer, electrolyte membrane and other application scenarios that require uniform dispersion of sulfide fine powder. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0025] This invention provides a method and application for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes. The method takes "wet refining - wet protection - redispersing at the application end" as the main line to achieve synergistic optimization of material processing and application.

[0026] The inventors first employed a low-DN, low-hygroscopic solvent for wet refining, reducing the solvent's effect on the Li content of the sulfide surface. +The process involves several key steps: first, coordination at specific sites reduces structural disturbance; second, maintaining the refined particles in a reversible soft agglomerate state prevents the formation of hard, difficult-to-disperse agglomerates; third, utilizing a solvent-wetting environment for wet storage and transportation reduces the risk of water absorption and performance degradation; and finally, during end-of-life pulping, redispersion is achieved through shearing and mixing to obtain a uniform ion transport network. Instead of relying on high-DN polar solvents or high-boiling-point dispersants to achieve complete dispersion during the wet refining stage, the final particle dispersion process is transferred to the subsequent pulping stage. This reduces sulfide grain boundary structural disturbance and conductivity loss while improving the material's stability and compatibility during storage, transportation, and subsequent pulping.

[0027] The low DN-low hygroscopic solvent system used in this invention preferably has the characteristics of low electron-donating ability, low water absorption, low surface tension and easy removal, with the number of electrons donated ≤10kcal / mol, more preferably ≤5kcal / mol; the dielectric constant of the solvent is 2-10, for example, but not limited to at least one of 2, 3, 4, 5, 6, 7, 8, 9 or 10 or any two of the following numerical ranges, preferably 3-8.

[0028] Specifically, the low DN-low hygroscopic solvent is selected from at least one of hydrofluoroethers, fluorinated aromatic hydrocarbons, low water-absorbing alkanes, or siloxanes, including but not limited to trifluorotoluene, methyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, ethoxy nonafluorobutyl ether, fluorotoluene, n-nonane, n-heptane, isoparaffins, or hexamethyldisiloxane, etc.

[0029] It should be noted that, in this application, the solvent is preferably used after being treated to remove water and oxygen in order to reduce the risk of water and oxygen introduction; therefore, the water content in the solvent is ≤500ppm, preferably ≤100ppm, and more preferably ≤50ppm.

[0030] Specifically, the present invention provides a method for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes, comprising the following steps: S1. Under an inert atmosphere, sulfide solid electrolyte powder and low DN-low hygroscopic solvent are mixed to form a wet grinding slurry, and the slurry is subjected to wet refining treatment.

[0031] In some preferred embodiments of this application, the sulfide solid electrolyte may be Li6PS5Cl, Li 5.4 PS 4.4 Cl 1.6 Li7P3S 11 Li3PS4, Li 10 GeP2S 12 Or its doped or modified materials.

[0032] In some preferred embodiments, the slurry solids content can be adjusted according to the grinding equipment and subsequent delivery form, preferably 10-50 wt%, for example, but not limited to at least one of 10 wt%, 20 wt%, 30 wt%, 40 wt% or 50 wt%, or a numerical range consisting of any two of them, more preferably 15-40 wt%.

[0033] Furthermore, wet refining can be achieved using sand milling, ball milling, acoustic resonance mixing, high-shear dispersion, or other equipment capable of providing shearing, collision, and deagglomeration effects. During the grinding process, the solvent enters the interparticle gaps and reduces the direct contact strength between particles, breaking up large particles and hard agglomerates, while simultaneously preventing the high-DN solvent from affecting the Li content on the sulfide surface. + Strong coordination at the sites. The goal of this stage is not to completely isolate and disperse all particles, but to form reversible soft aggregates that are mainly bound by van der Waals forces, capillary forces, or weak adsorption.

[0034] S2. The refined sulfide solid electrolyte is stored or transported in a wet form containing solvent.

[0035] In some preferred embodiments of this application, different processing methods can be selected according to product delivery requirements. When wet delivery is required, the slurry state can be adjusted by means of settling, centrifugation, filtration, or concentration to form a wet slurry, wet filter cake, or solvent-wetted powder, which can then be stored and transported in a sealed container. Since the surface of the sulfide particles is in a low-hygroscopic solvent-wetted environment, the chance of external moisture entering the particle surface can be reduced, thereby lowering the risk of water absorption caused by packaging micro-leakage or short-term environmental fluctuations.

[0036] Preferably, the solvent content in the wet sulfide solid electrolyte containing solvent is 5-80 wt%, for example, but not limited to at least one of 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt% or 80 wt%, or any two of these values, more preferably 10-50 wt%.

[0037] Meanwhile, the wet sulfide solid electrolyte can be stored or transported in sealed containers, aluminum-plastic composite bags, metal cans or solvent-resistant packaging containers as needed.

[0038] S3. In use, the solvent-containing wet sulfide solid electrolyte is introduced into the slurry system, and the reversible soft agglomeration structure is depolymerized twice through dispersion treatment to obtain a uniformly dispersed sulfide solid electrolyte slurry.

[0039] It should be noted that the wet material can be directly added to the electrode slurry or electrolyte membrane slurry system, or it can be first dried under low temperature vacuum before being added. Preferably, the drying temperature is <120℃, more preferably 40-100℃, for example, but not limited to at least one of 40℃, 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃, or any range of two of these values. Low temperature vacuum drying can avoid structural changes and enhanced residual adsorption caused by high temperature treatment. Because the selected solvent has a moderate boiling point, low water absorption and weak reactivity with sulfides, it is not easy to form a strong residual layer after drying, which is beneficial to maintaining the interfacial integrity of the electrolyte particles.

[0040] When the sulfide electrolyte is stored or transported in a wet state, and then dried and further dispersed in a slurry system, the particle size D50 of the redispersed powder is less than 80% of the particle size D50 of the powder obtained after storage and drying, preferably less than 60%. The present invention constructs a stable wetting and protective environment on the particle surface through a low electron-donating solvent with low hygroscopicity, so that the refined electrolyte particles exist in a reversible soft agglomerate state. The agglomerates formed during the drying process can be effectively opened during the subsequent secondary dispersion in the slurry, thereby restoring the fineness to a state close to that of grinding.

[0041] In contrast, powders produced by wet milling followed by immediate drying in traditional processes, or powders milled using solvents with high electron-donating numbers, exhibit a significant increase in particle size after storage. The D50 after redispersement typically exceeds 60% of the stored dry powder, and may even approach or exceed 80%. The particle size recovery characteristics of this invention ensure that the sulfide electrolyte retains excellent redispersibility and processing adaptability after long-term storage and transportation, providing a reliable basis for particle size control in downstream continuous slurry preparation and electrode fabrication.

[0042] In some preferred embodiments, the wet or dried sulfide electrolyte is added to a slurry system containing a binder, a conductive agent, a positive electrode active material, or a film-forming component, and then subjected to secondary deagglomeration through high-speed stirring, planetary mixing, acoustic resonance mixing, three-roll dispersion, or other shearing processes. The binder molecular chains can create steric hindrance on the particle surface, and the conductive agent and active material particles can change the contact mode between sulfide particles, causing the aforementioned reversible soft agglomerate structure to reopen, thereby forming a uniform and continuous ion transport network in the electrode or electrolyte membrane.

[0043] The binder includes, but is not limited to, PVDF, SEBS, SBS, PTFE or PEO; the conductive agent includes, but is not limited to, conductive carbon black, carbon nanotubes, carbon nanofibers or graphene.

[0044] In some preferred embodiments of this application, the D50 of the dispersed sulfide solid electrolyte particles is ≤1.5μm, preferably ≤1.0μm.

[0045] Through the above technical solution, this invention transforms the traditional wet grinding process's "strong dispersion—strong drying—dry powder transportation" mode into a "low-damage pre-refining—wet protection—end-of-use redispersion" mode. The low-DN solvent reduces the impact on sulfide grain boundaries and Li... + The disturbance of the conduction channels and the low hygroscopic solvent provide water-proof protection during storage and transportation, enabling the sulfide electrolyte to achieve low-damage refinement during the grinding stage and maintain a reversible soft agglomerate state. This reversible soft agglomerate structure avoids the formation of irreversible hard agglomerates during drying and transportation. During storage and transportation, the solvent-wetting environment provides water-proof protection for the sulfide particles. Subsequent slurry redispersion ensures the uniform distribution of the material in the electrode or film layer. Thus, this method can improve the storage and transportation stability, slurry adaptability, and batch-use consistency of the sulfide electrolyte while maintaining its high ionic conductivity.

[0046] The present invention also provides a wet sulfide solid electrolyte composition, the composition comprising sulfide solid electrolyte particles and a low DN-low hygroscopic organic solvent; the sulfide solid electrolyte particles are in a reversible soft agglomeration state.

[0047] It should be noted that the reversible soft agglomeration state refers to the particle aggregation state in which sulfide electrolyte particles are mainly bound together by van der Waals forces, capillary forces or weak adsorption, and can be re-deagglomerated during subsequent slurry shearing or mixing.

[0048] Preferably, after the composition is stored in a sealed container for 30 days, the ionic conductivity of the dried sulfide solid electrolyte powder is maintained at not less than 80%, more preferably not less than 90%.

[0049] Furthermore, the present invention provides a sulfide solid electrolyte slurry, which is prepared by the above method, or obtained by depolymerization and dispersion of the above wet sulfide solid electrolyte composition.

[0050] Finally, the present invention provides an all-solid-state battery in which the positive electrode or electrolyte film is formed using the above-mentioned sulfide solid electrolyte slurry.

[0051] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0052] Example 1 This embodiment provides a method for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes, including the following steps: 10 g of sulfide solid electrolyte Li5.4PS4.4Cl1.6 powder was weighed. The powder had an initial D50 of 8.6 μm and an ionic conductivity of 13.2 mS / cm at room temperature. In an argon-atmospheric glove box, the powder was added to a mixed solvent of 40 g of trifluorotoluene and n-heptane in a 1:1 mass ratio, and stirred to form a slurry. 200 g of 0.3 mm diameter zirconia beads were added to the slurry. The system was then sealed and placed in an acoustic resonance mixer, treated at a vibration intensity of 70 g for 2 h, with the treatment temperature controlled below 25 °C. After treatment, the zirconia beads were separated by filtration to obtain a wet sulfide electrolyte slurry.

[0053] The obtained wet slurry was concentrated by centrifugation to obtain a wet filter cake with a solvent content of approximately 35 wt%. The wet filter cake was sealed in an aluminum-plastic composite bag and left at room temperature for 30 days. After storage, the wet filter cake was dried under vacuum at 60°C for 8 hours to obtain dried electrolyte powder. A portion of the wet filter cake was then directly added to the electrolyte membrane slurry system and redispersed by planetary mixing for 30 minutes in the presence of SEBS binder and xylene solvent.

[0054] Example 2 This embodiment provides a method for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes. The conditions and steps are the same as in Example 1, except that the solvent is a mixed solvent composed of methyl nonafluorobutyl ether and ethoxy nonafluorobutyl ether in a mass ratio of 1:1.

[0055] Example 3 This embodiment provides a method for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes. The conditions and steps are the same as in Example 1, except that the solvent is a mixed solvent composed of m-fluorotoluene and isoparaffins in a mass ratio of 3:7.

[0056] Example 4 This embodiment provides a method for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes. The conditions and steps are the same as in Example 1, except that the solvent is methyl nonafluorobutyl ether.

[0057] Example 5 This embodiment provides a method for grinding, wet storage and transportation, and redispersing of sulfide solid electrolytes. The conditions and steps are the same as in Example 1, except that the solvent is a mixed solvent composed of hexamethyldisiloxane and n-heptane in a mass ratio of 1:1.

[0058] Example 6 This embodiment provides a method for grinding, wet storage and transportation, and redispersing a sulfide solid electrolyte. The conditions and steps are the same as in Example 1, except that after wet refining, centrifugal concentration is not performed; instead, the resulting wet slurry is directly sealed and stored for 30 days. After storage, the wet slurry is directly added to a positive electrode slurry system, which includes a high-nickel ternary positive electrode material, conductive carbon black, a binder, and a low-polarity organic solvent. After planetary mixing and high-speed dispersion, a positive electrode composite slurry is obtained.

[0059] Comparative Example 1 This embodiment provides a method for grinding, storing, transporting, and redispersing sulfide solid electrolytes, including the following steps: Weigh 10 g of the same sulfide solid electrolyte powder as in Example 1 and add it to 40 g of n-heptane. Other grinding conditions are the same as in Example 1. After grinding, immediately dry the powder under vacuum at 60°C for 8 h to obtain a dry powder sample. After sealing and storing the sample for 30 days, add it to the electrolyte membrane slurry system for redispersibility.

[0060] Comparative Example 2 This comparative example provides a method for grinding, storing, transporting, and redispersing a sulfide solid electrolyte. The conditions and steps are the same as in Example 1, except that the solvent is 40 g xylene; after grinding, the electrolyte is immediately dried into powder and sealed for storage for 30 days before being added to the electrolyte membrane slurry system for redispersing.

[0061] Comparative Example 3 This comparative example provides a method for grinding, storing, transporting, and redispersing a sulfide solid electrolyte. The conditions and steps are the same as in Example 1, except that the solvent is a mixed solvent consisting of 40 g xylene and butyl acetate in a mass ratio of 4:1. After grinding, the mixture is immediately dried into powder and sealed for storage for 30 days before being added to the electrolyte membrane slurry system for redispersing.

[0062] Comparative Example 4 This comparative example provides a method for grinding, storing, transporting, and redispersing a sulfide solid electrolyte. The conditions and steps are the same as in Example 1, except that no solvent is added, and 200 g of 0.3 mm diameter zirconia beads are added. The mixture is then dry-milled in a sealed ball mill jar for 2 hours to obtain a dry-ground powder. The resulting powder is then sealed and stored for 30 days before being redispersed as a slurry.

[0063] Comparative Example 5 This comparative example provides a method for grinding, storing, transporting, and redispersing a sulfide solid electrolyte. The conditions and steps are the same as in Example 1, except that after wet refining, the resulting slurry is dried directly under vacuum at 120°C for 12 hours to completely remove the solvent and obtain dry powder. After being sealed and stored for 30 days, it is used for slurry redispersing.

[0064] Experimental Example 1 The performance of the sulfide solid electrolytes prepared in the examples and comparative examples was tested, and the results are shown in Table 1. The test methods are as follows: Particle size testing: Take 20 mg of the treated electrolyte sample and add it to 5 mL of dehydrated anisole or corresponding low-DN dispersion medium. After ultrasonic treatment for 3 min, perform laser particle size analysis and record the D50. For wet samples, take a sample with equivalent solids content, dilute it with the corresponding solvent, and then test it.

[0065] Ionic conductivity test: 200 mg of electrolyte powder was weighed and placed in a mold with a diameter of 10 mm. It was pressed into a sheet under a pressure of 216 MPa. After measuring the sheet thickness, a blocked electrode battery was assembled. The AC impedance was tested and the room temperature ionic conductivity was calculated using an electrochemical workstation.

[0066] Wet storage and transportation stability test: The wet samples obtained in the example were sealed and stored for 30 days; as an accelerated evaluation, the outer packaging of the sealed sample could be placed in an environment with a dew point of -40°C for 24 h, and then the sample was dried and the changes in conductivity and particle size were tested.

[0067] Redispersion performance test: The stored wet sample or dry powder sample is added to the electrolyte membrane slurry system or positive electrode composite slurry system containing binder. After planetary mixing for 30 min, the sample is taken to test the D50 after redispersion.

[0068] Table 1. Performance test results of sulfide solid electrolytes

[0069] Based on the above experimental results, it can be seen that Examples 1 to 6 used low electron-donating solvents with low hygroscopicity for wet refining, and after storage in a wet or solvent-wetted state, the materials still maintained high ionic conductivity and good redispersibility. Although some particles showed a certain degree of particle size increase in the dried powder after storage in some examples, the D50 was significantly reduced after shear mixing in the subsequent slurry system, indicating that the agglomeration was mainly reversible soft agglomeration rather than irreversible hard agglomeration.

[0070] Examples 1 and 3 demonstrate that the system composed of fluoroaromatic solvents and low-hygroscopic alkanes can provide good wetting, refining, and storage / transport protection while maintaining low reactivity, exhibiting excellent conductivity retention and redispersibility. Examples 2 and 4 show that hydrofluoroether systems, represented by methyl nonafluorobutyl ether, can also achieve good wet protection and secondary depolymerization effects. Example 5 illustrates that siloxane / alkane systems can also be used to construct a low-hygroscopic, weakly coordinated wet protection environment. Example 6 shows that the refined wet slurry can be directly introduced into subsequent slurry preparation processes without complete drying, thereby reducing drying-induced agglomeration and interfacial degradation.

[0071] Comparative Examples 1 and 2 used traditional low-polarity alkane or aromatic hydrocarbon systems. After wet milling, the particle size was relatively large, and agglomeration intensified further after storage. Even after subsequent slurry redispersibility, the particle size was difficult to recover to a smaller size, indicating that a simple low-reactivity solvent cannot simultaneously achieve both refining efficiency and redispersibility. In Comparative Example 3, the addition of butyl acetate resulted in better particle size control, but a significant decrease in ionic conductivity, indicating that high-DN or strongly reactive solvents can adversely affect the sulfide surface and grain boundaries. Comparative Example 4 shows that dry ball milling easily forms severe hard agglomerates, which are difficult to fully open through subsequent slurry preparation. Comparative Example 5 shows that immediate high-temperature complete drying after wet milling exacerbates particle bridging and hard agglomeration, leading to a decrease in redispersibility.

[0072] The above results show that the present invention, through a combination of low-damage wet refining, wet storage and transportation protection, and secondary depolymerization at the point of use, can improve the storage and transportation stability and subsequent slurry dispersion performance of the sulfide electrolyte while maintaining its ionic conductivity.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for grinding, wet storage and transportation, and redispersing a sulfide solid electrolyte, characterized in that, Includes the following steps: Under an inert atmosphere, sulfide solid electrolyte powder and a low DN-low hygroscopic solvent are mixed to form a wet grinding slurry, and the slurry is then subjected to wet refining treatment. The refined sulfide solid electrolyte is stored or transported in a wet form containing solvent; In use, the solvent-containing wet sulfide solid electrolyte is introduced into the slurry system, and the reversible soft agglomerates are dispersed to undergo secondary depolymerization, resulting in a uniformly dispersed sulfide solid electrolyte slurry.

2. The method according to claim 1, characterized in that, The low DN-low hygroscopic solvent has an electron-donating number ≤10 kcal / mol; the dielectric constant of the solvent is 2-10; And / or, the low DN-low hygroscopic solvent is selected from at least one of hydrofluoroethers, fluorinated aromatic hydrocarbons, low water-absorbing alkanes, or siloxanes.

3. The method according to claim 2, characterized in that, The low DN-low hygroscopic solvent is selected from at least one of trifluorotoluene, methyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, ethoxy nonafluorobutyl ether, fluorotoluene, n-nonane, n-heptane, isoalkanes, or hexamethyldisiloxane.

4. The method according to claim 1, characterized in that, The low DN-low hygroscopic solvent needs to be dehydrated and deoxygenated before use; And / or, the water content in the solvent is ≤500ppm.

5. The method according to claim 1, characterized in that, The solid content of the wet grinding slurry is 10-50 wt%.

6. The method according to claim 1, characterized in that, The wet refining process employs at least one of the following: sand milling, ball milling, acoustic resonance mixing, high shear dispersion, or planetary mixing.

7. The method according to claim 1, characterized in that, The solvent content in the solvent-containing wet sulfide solid electrolyte is 5-80 wt%.

8. The method according to claim 1, characterized in that, The wet sulfide solid electrolyte is stored or transported in a sealed container, aluminum-plastic composite bag, metal can, or solvent-resistant packaging container.

9. The method according to claim 1, characterized in that, The solvent-containing wet sulfide solid electrolyte also undergoes low-temperature vacuum drying before being introduced into the slurry system; And / or, the drying temperature is <120°C.

10. The method according to claim 1, characterized in that, The slurry system includes one or more of the following: binder, conductive agent, positive electrode active material, or film-forming polymer; And / or, the adhesive comprises one or more of PVDF, SEBS, SBS, PTFE, or PEO; And / or, the conductive agent includes one or more of conductive carbon black, carbon nanotubes, carbon nanofibers, or graphene.

11. The method according to claim 1, characterized in that, The D50 of the dispersed sulfide solid electrolyte particles is ≤1.5μm.

12. A wet sulfide solid electrolyte composition, characterized in that, The composition comprises sulfide solid electrolyte particles and a low-DN, low-hygroscopic organic solvent; the sulfide solid electrolyte particles are in a reversible soft agglomeration state.

13. The wet sulfide solid electrolyte composition according to claim 12, characterized in that, After the composition is stored in a sealed container for 30 days, the ionic conductivity of the dried sulfide solid electrolyte powder is maintained at no less than 80%.

14. A sulfide solid electrolyte slurry, characterized in that, The slurry is prepared by the method of any one of claims 1-11, or by depolymerization and dispersion of the wet sulfide solid electrolyte composition of claim 12 or 13.

15. An all-solid-state battery, characterized in that, Its positive electrode or electrolytic membrane is formed using the sulfide solid electrolyte slurry described in claim 14.

Images