High-dispersibility sulfide solid electrolyte composite material, preparation method thereof and all-solid-state battery

Abstract

The application provides a high-dispersibility sulfide solid electrolyte composite material and a preparation method thereof and a full solid-state battery, and relates to the technical field of solid-state battery materials.The composite material comprises sulfide solid electrolyte particles and an interface modification polymer with a specific structure.The polymer has an amphiphilic structure, and comprises a surface affinity segment capable of specifically interacting with the surface of the electrolyte and a polyether space extension segment.The core of the application is that the polymer is used for in-situ interface modification in a wet crushing process, and an ideal particle size distribution is actively controlled and formed.The design effectively eliminates harmful fine powder, and solves the problems of particle agglomeration, wide distribution and multiple side reactions in the traditional fine process.The obtained composite material has high ionic conductivity and good interface stability, and is suitable for preparing high-performance full solid-state battery electrodes and batteries, and significantly improves the initial efficiency and cycle life.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery materials technology, specifically to a highly dispersed sulfide solid electrolyte composite material with a precisely controllable particle size distribution. More specifically, this invention relates to a composite material in which particle size and distribution are synergistically regulated through interface-modified polymers with specific structures, its preparation method, and an all-solid-state battery comprising this composite material. Background Technology

[0002] Sulfide solid electrolytes (such as Li3PS4, Li6PS5Cl, etc.) have extremely high room temperature ionic conductivity (10⁻⁶ Ω·cm). - 3 S·cm -1 (Above) It is considered one of the most promising key materials for realizing high-energy-density all-solid-state lithium batteries. However, its inherent rigid solid-solid contact characteristics result in huge electrode / electrolyte interface impedance, which severely limits the rate performance and cycle life of the battery.

[0003] To improve interfacial contact, the industry generally adopts a strategy of refining electrolyte particles. Patent CN119275332A discloses a sulfide electrolyte with a mean particle size D50 of 10 nm to 5000 nm and a particle size distribution satisfying 0.9 ≤ (D90) nm. The ratio of D10 / D50 ≤ 2. While this method addresses particle size distribution, its particle size range is too wide (D50 as low as 10 nm), and it fails to effectively control the lower limit of D10. This may result in the product containing a large number of extremely fine particles (e.g., D10 < 0.3 μm). These fine powders have high specific surface area and high surface energy, making them prone to side reactions with air / solvents. Furthermore, they can cause severe agglomeration, slurry sedimentation, or rheological deterioration in subsequent electrode slurry preparation, significantly affecting the uniformity of the electrode film and the connectivity of ion transport channels. Patent CN119009076A provides a refining method that utilizes the synergistic effect of an alkane dispersant and an oxygen-containing solvent to obtain powder with a particle size of approximately 500 nm through ball milling. However, the alkane dispersant used in this method only has a physical dispersing effect and lacks strong specific interaction with the sulfide particle surface, failing to effectively "modify" the particle surface during the crushing process to regulate its growth and morphology. Therefore, the particle size distribution (span value) of the resulting particles is difficult to control precisely, and they are prone to re-agglomeration after drying. Other technologies, such as CN115763951A and CN116505059A, mostly focus on reducing the average particle size through solvent engineering or physical crushing, but they generally do not take a "particle surface interface engineering" approach to design dedicated dispersants and stabilizers to actively "shape" the ideal particle size distribution and simultaneously solve the two major problems of excessive fine powder and severe agglomeration.

[0004] In summary, existing technologies have failed to provide a reliable preparation method for a sulfide electrolyte composite material that achieves a suitable main particle size (D50 approximately 0.8-1.0 μm), effectively eliminates harmful fine particles (D10 > 0.3 μm), and ensures a highly concentrated particle size distribution (small Span value). Developing a high-performance sulfide electrolyte capable of precisely controlling particle size distribution is crucial for promoting the industrialization of all-solid-state batteries. Summary of the Invention

[0005] The present invention aims to overcome the above-mentioned defects of the prior art and provide a highly dispersible sulfide solid electrolyte composite material that achieves precise control of particle size distribution through molecular design and interface modification of polymers.

[0006] One of the objectives of this invention is to provide a highly dispersed sulfide solid electrolyte composite material.

[0007] The second objective of this invention is to provide a method for preparing the highly dispersed sulfide solid electrolyte composite material.

[0008] A third objective of this invention is to provide an all-solid-state battery electrode, comprising the highly dispersed sulfide solid electrolyte composite material.

[0009] The fourth objective of this invention is to provide an all-solid-state battery, including the all-solid-state battery electrode.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a highly dispersible sulfide solid electrolyte composite material, comprising sulfide solid electrolyte particles and an interface-modified polymer at least partially coating the periphery of the sulfide solid electrolyte particles.

[0011] The sulfide solid electrolytes include, but are not limited to, Li3PS4 and Li7P3S. 11 Li 10 GeP2S 12 Systems such as Li6PS5Cl, Li2S-P2S5, Li2S-SiS2, and Li2S-B2S3.

[0012] The interface-modified polymer is a functional polymer with a defined amphiphilic structure. Its molecular design includes two key segments: one is a surface affinity segment containing specific functional groups (such as sulfonic acid groups or phosphonic acid groups), configured to form strong coordination bonds or ion-dipole interactions with lithium ions, phosphorus atoms, or sulfur atoms on the surface of sulfide solid electrolyte particles, achieving firm anchoring; the other is a spatially extended segment composed of polyether, which fully extends in aprotic solvents, preventing particles from approaching and merging through a strong steric hindrance effect. The surface affinity segment and the spatially extended segment are connected by covalent bonds.

[0013] The surface affinity segment contains at least one functional group selected from sulfonic acid group, phosphonic acid group, carboxyl group, thiol group, silanol group, and their ionic forms.

[0014] The spatially extended segments are composed of polyethylene oxide segments, polypropylene oxide segments, or their random / block copolymers.

[0015] The core innovation of this invention lies in the ability to actively "shape" the final morphology and distribution of particles during wet crushing through in-situ interfacial modification and regulation of the aforementioned specific structural polymer. Specifically, the highly dispersed sulfide solid electrolyte composite material exhibits a specific particle size distribution regulated by the interfacial modified polymer, satisfying: D10 > 0.3 μm, 0.8 μm ≤ D50 ≤ 1.0 μm, D90 < 2.5 μm, and a particle size distribution width Span = (D90 - D10) / D50 < 2.5. Simultaneously, the mass fraction of the interfacial modified polymer is 0.1% to 2.0%.

[0016] This unique particle size distribution characteristic has the following technical significance: 1. Elimination of harmful fine particles: The key limitation of D10>0.3μm ensures that the content of ultrafine particles (<0.3μm) in the composite material is extremely low, which fundamentally reduces highly active surface sites and significantly improves the chemical stability of the material and the processing performance of the electrode paste.

[0017] 2. Optimize the main particle size range: strictly control D50 within the "golden range" of 0.8-1.0μm. This ensures sufficient contact with the electrode active material to reduce interfacial impedance while avoiding the problems of excessively small particle size leading to a sharp increase in specific surface area and decreased stability.

[0018] 3. Ensure highly concentrated distribution: D90 < 2.5 μm and Span < 2.5 indicate highly uniform particle size and extremely narrow distribution range. This monodisperse characteristic is conducive to the formation of a tightly packed electrolyte layer with a uniform pore structure, providing a fast and consistent transport channel for lithium ions.

[0019] In a preferred embodiment, the interface-modified polymer has a comb-like, grafted, or block molecular topology, with a number-average molecular weight (Mn) of 1000 to 10000 g / mol. These characteristics collectively ensure efficient anchoring and stable dispersion of the polymer at low addition levels, and facilitate removal during post-processing.

[0020] Secondly, the present invention provides a method for preparing a highly dispersed sulfide solid electrolyte composite material, comprising the following steps: The sintered sulfide solid electrolyte block, aprotic organic solvent, and interface-modified polymer were mixed and then subjected to wet crushing, followed by separation and drying.

[0021] The aprotic organic solvents include, but are not limited to, n-hexane, n-heptane, xylene, benzene, trimethylbenzene, cyclohexane, n-butyl ether, etc.

[0022] Thirdly, the present invention provides an all-solid-state battery electrode comprising the above-mentioned highly dispersed sulfide solid electrolyte composite material.

[0023] Fourthly, the present invention provides an all-solid-state battery, including the all-solid-state battery electrode described above.

[0024] Beneficial effects: (1) Precise and coordinated control of particle size distribution was achieved: For the first time, through interface modification of polymer with specific structure, multiple precise constraints on D10, D50, D90 and Span values ​​were simultaneously achieved in the sulfide electrolyte system, and an ideal particle group with "appropriate main particle size, no harmful fine powder, and highly concentrated distribution" was obtained, which solved the problem that existing technologies could not avoid excessive fine powder.

[0025] (2) It provides excellent dispersion and anti-agglomeration properties: The polymer’s “anchoring-spatial stability” synergistic mechanism ensures that the particles maintain excellent dispersion during wet crushing, drying and subsequent processing, overcoming the defects of weak dispersant effect and easy particle reagglomeration.

[0026] (3) Improved overall battery performance: The electrode prepared by the composite material of the present invention has good interface contact and uniform ion transport, which can significantly improve the first coulombic efficiency, rate performance and long cycle stability of the all-solid-state battery.

[0027] The present invention has been described in detail above; however, the above embodiments are merely illustrative in nature and are not intended to limit the invention. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following embodiments. Attached Figure Description

[0028] Figure 1 The particle size distribution curve of the sulfide solid electrolyte provided in Example 1 is shown. Figure 2 A scanning electron microscope image of the sulfide solid electrolyte provided in Example 1 is shown. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0030] Unless otherwise specified, the raw materials, reagents, and methods used in the embodiments are all conventional raw materials, reagents, and methods in the art.

[0031] In all the following examples and comparative examples, a uniform method was used for preparation and testing: Particle size distribution: Measured using a laser particle size analyzer, the values ​​of D10, D50, and D90 are reported, and Span = (D90 - D10) / D50 is calculated.

[0032] Ionic conductivity test: Weigh 150mg of sulfide solid electrolyte material and place it in a mold with an inner diameter of 10mm. Press it down with stainless steel current collectors from top to bottom and apply a pressure of 370MPa for 5min. Perform AC impedance test at 25℃ using an electrochemical workstation. The amplitude of the AC current is 15mV and the frequency range is 0.01Hz~1MHz.

[0033] Assembly of solid-state lithium batteries: Solid-state lithium batteries consist of a high-nickel cathode material, a lithium-indium alloy anode, and a sulfide solid electrolyte material prepared in the above embodiments or comparative examples. The specific assembly process is as follows: First, 100 mg of sulfide solid electrolyte is placed into a Φ10 mm mold and pressed into an intermediate layer under a pressure of 200 MPa; then, 10 mg of composite cathode material (composed of 9 mg of high-nickel cathode material and 1 mg of sulfide solid electrolyte) is added to one end of the intermediate layer and pressed into shape under a pressure of 200 MPa; finally, a certain amount of lithium-indium alloy anode is added to the other end of the intermediate layer and assembled into an all-solid-state lithium battery under a pressure of 240 MPa.

[0034] Testing of all-solid-state lithium batteries: Test temperature 25℃, voltage range 2.6~4.4V vs. Li + / Li. The full cell at 0.1C (1C = 200mA g). -1 Charge-discharge cycle tests were conducted at a current density of 10 ...

[0035] Preparation Example 1: Synthesis of Interface Modified Polymer I (polyethylene oxide as the main chain, with short chains containing sulfonic acid groups as side branches, Mn≈2500) a. Take maleic anhydride-styrene copolymer (based on the molar amount of anhydride groups) that has been vacuum dried (80℃, 12h, vacuum degree ≤0.09MPa) and add it to a dry three-necked flask with a slightly excess of mPEG-OH (anhydride group:mPEG-OH = 1:1.1, molar ratio); add anhydrous DMF (the amount of solvent is 3 times the total mass of the system to ensure complete dissolution of the material), and stir to fully dissolve the material. Then add 4-dimethylaminopyridine (DMAP, catalyst, amount is 5 mol% of the molar amount of anhydride groups) and triethylamine (Et3N, acid-binding agent, amount is 1.5 times the molar amount of anhydride groups), place the three-necked flask in an inert gas (nitrogen or argon) protective atmosphere (pre-evacuate - replace with inert gas 3 times to eliminate air interference), heat in an oil bath at 75℃, and stir at a constant temperature for 24h; after the reaction is completed, turn off the heating and allow the system to cool naturally to room temperature.

[0036] b. Under inert gas protection, transfer the cooled reaction solution to another dry three-necked flask, add anhydrous THF (solvent volume twice the volume of the reaction solution), and stir to dissolve. Cool the system to 0°C in an ice-water bath, and slowly add sodium hydride (NaH, 1.2 times the molar amount of mPEG-OH, to avoid violent local exothermic reactions caused by adding it all at once), stirring at low temperature for 30 min to ensure that the terminal hydroxyl groups of the PEO side chain are completely converted into sodium alkoxide active species. Dissolve 1,3-propanesulfonate lactone in 3 times its volume of anhydrous THF to prepare a 1 mol / L solution, and slowly add it dropwise to the above active solution through a constant pressure dropping funnel (dropping rate controlled at 1 drop / second, maintaining the system temperature ≤5°C); after the addition is complete, remove the ice-water bath, allow it to warm naturally to room temperature, and continue stirring the reaction for 12 h.

[0037] c. After the reaction is complete, slowly add a small amount of deionized water (about 1 / 10 of the reaction liquid volume) to the system to quench unreacted sodium hydride, and stir for 10 min. Transfer all the reaction solution to a dialysis bag with a molecular weight cutoff of 3500 Da, and dialyze it with deionized water for 3-4 days (changing the deionized water 2-3 times a day to ensure thorough dialysis) to completely remove inorganic salts, unreacted 1,3-propanesulfonate lactone, and its hydrolysis products. After dialysis, collect the solution in the dialysis bag and freeze-dry it in a freeze dryer (-50℃, vacuum ≤10 Pa) for 48 h to obtain a white, fluffy solid—a comb-shaped PEO polymer with sulfonic acid groups at the end of the side chains.

[0038] Example 1 This embodiment provides a sulfide solid electrolyte material and its preparation method, wherein the sulfide used is Li 5.5 PS 4.5 ClBr 0.5 The specific preparation method is as follows: (1) In the glove box, according to Li 5.5 PS 4.5 ClBr 0.5 The elemental proportions for the sample were as follows: Li₂S (3.18g), P₂S₅ (3.85g), LiCl (1.47g), and LiBr (1.50g). These raw materials were placed in a 50ml zirconia ball mill jar. Zirconia balls with diameters of 10mm, 5mm, and 3mm were added in 30g, 15g, and 5g respectively. The sealed jar was placed on a ball mill, and the milling speed was set. The milled sample was collected and sealed in a vacuum quartz tube for calcination. The calcination temperature was controlled by a programmed temperature rise. The sintering process consisted of two stages: a heating rate of 4℃ / min, a first-stage sintering temperature of 260℃ and a holding time of 3h, and a second-stage sintering temperature of 540℃ and a holding time of 8h. After sintering, the temperature was lowered to 50℃ at a rate of 4℃ / min.

[0039] It should be noted that the above is only one method for synthesizing sulfide solid electrolyte materials. This patent does not limit the specific synthetic route of sulfide solid electrolyte materials, which can be obtained by any method. Alternatively, commercially available electrolyte materials can be directly purchased for further processing.

[0040] (2) In an argon-protected glove box, the interface-modified polymer I was dissolved in 50 mL of anhydrous n-heptane, and the amount of dispersant added was 1 wt%. (3) Take 10g of coarse Li particles 5.5 PS 4.5 ClBr 0.5 Add the above solution, transfer it to a ball mill jar, and add zirconia grinding balls (ball-to-material ratio 20:1). (4) Wet ball milling at 400 rpm for 6 hours on a planetary ball mill; (5) After ball milling, the slurry is separated by centrifugation, and the solid part is vacuum dried at 120°C for 12 hours to obtain the final composite material powder.

[0041] Preparation Example 2: Synthesis of Interface-Modified Polymer II The three-necked flask was dried at 120℃ for 2 hours, cooled, and then evacuated to N2 three times. PPG 3200 (5.0 g) and anhydrous dichloromethane (50 mL) were added and stirred to dissolve. The mixture was cooled to 0℃ in an ice-water bath, and triethylamine (4.5 g) was slowly added dropwise while stirring for 10 min to form a hydroxy-triethylamine complex. Dimethyl chlorophosphonate (3.5 g) was slowly added dropwise using a constant-pressure dropping funnel, controlling the dropping rate to keep the system temperature below 5℃ and the dropping time ≥30 min. After the addition was complete, the reaction was carried out at 0℃ for 2 hours, and then continued at room temperature for 8 hours. Concentrated hydrochloric acid (10 mL) was added, and the mixture was heated to 60℃ and stirred for 4 hours to hydrolyze dimethyl phosphonate to phosphonic acid groups. The reaction solution was transferred to a dialysis bag and dialyzed with deionized water for 3 days (changing the water 2-3 times daily) to remove inorganic salts and small molecule impurities. The dialysate was freeze-dried at -50℃. After 48 hours, a white, fluffy solid was obtained—terminated phosphonate-modified polyoxypropylene (Mn≈3200).

[0042] Example 2 The only difference between this embodiment and Embodiment 1 is that the interface polymer I is replaced with interface modified polymer II (polypropylene oxide as the main chain, phosphonic acid groups grafted to the end groups, Mn≈3200), and the amount added is 0.5wt%.

[0043] Example 3 The only difference between this embodiment and Embodiment 1 is that the amount of interfacial polymer I added is 0.2 wt%.

[0044] Example 4 The only difference between this embodiment and Embodiment 1 is that the amount of interfacial polymer I added is 2wt%.

[0045] Preparation Example 3: Synthesis of Interface-Modified Polymer III The three-necked flask was dried at 120℃ for 2 hours, cooled, and then evacuated three times with N2. Pluronic P84 (5.0 g) and anhydrous dichloromethane (50 mL) were added and stirred to dissolve. The mixture was cooled to 0℃ in an ice-water bath, and triethylamine (4.3 g) was slowly added dropwise while stirring for 10 min to form a hydroxy-triethylamine complex. Chlorosulfonic acid (2.5 g) was slowly added dropwise using a constant-pressure dropping funnel, with the dropping rate controlled so that the system temperature did not exceed 5℃ and the dropping time ≥30 min. After the addition was complete, the mixture was reacted at 0℃ for 2 hours and then at room temperature for another 8 hours. The reaction solution was poured into 100 mL of ice water, stirred for 30 min, allowed to stand and separate into layers, and the aqueous phase was collected. The aqueous phase was transferred to a dialysis bag and dialyzed with deionized water for 3 days (changing the water 2-3 times a day). The dialysate was freeze-dried (-50℃, 48 h) to obtain a white, fluffy solid—terminated sulfonated PEO-PPO-PEO triblock copolymer (Mn≈5000).

[0046] Example 5 The only difference between this embodiment and Embodiment 1 is that the interfacial polymer I is replaced with interfacial modified polymer III (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, with sulfonic acid end groups, Mn≈5000), and the amount added is 1wt.

[0047] Example 6 The only difference between this embodiment and Embodiment 1 is that the sulfide used is derived from Li 5.5 PS 4.5 ClBr 0.5 Replace with Li6PS5Cl.

[0048] Comparative Example 1 The only difference between this comparative example and Example 1 is that no polymer is added in step (2).

[0049] Comparative Example 2 The only difference between this comparative example and Example 1 is that in step (2), the polymer is replaced with an equal mass (1.0 wt%) of ordinary polyvinylpyrrolidone (PVP, Mn≈10,000). This comparative example simulates the use of conventional polymeric dispersants in the prior art.

[0050] Comparative Example 3 The only difference between this comparative example and Example 1 is that in step (2), the polymer is replaced with an equal mass (1.0 wt%) of sodium dodecylbenzenesulfonate (SDBS). This comparative example simulates the use of small molecule surfactants.

[0051] Comparative Example 4 The only difference between this comparative example and Example 1 is that the amount of polymer added is increased to 5.0 wt%. This comparative example is used to explore the effect of excess polymer.

[0052] The test results of the sulfide solid electrolyte composite materials prepared in Examples 1-6 and Comparative Examples 1-4 are shown in the table below.

[0053]

[0054] Results Analysis and Conclusions: 1. Verification of the Invention's Effectiveness (Examples 1, 2, 5, 6): All examples successfully achieved the core objectives of D10 > 0.3 μm, D50 between 0.8 and 0.95 μm, and Span < 2.5, demonstrating that specific polymers with different structures (comb-like, grafted, block) can effectively "regulate" the formation of the desired particle size distribution. The corresponding batteries exhibited excellent cycle retention (>85%), proving the practical value of this material in batteries.

[0055] 2. Exploration of Key Parameter Boundaries (Examples 3, 4): Example 3 (low addition amount 0.2%): Span value (2.3) < 2.5, D10 (0.36μm) slightly high. This indicates that the lower bound of the addition amount range of 0.1%-2.0% is effective, but the controllability approaches its limit when approaching the lower bound. Example 4 (high addition amount 2.0%): The particle size distribution is optimal (Span=1.80), but the ionic conductivity begins to decrease slightly, and the battery performance is also slightly reduced. This proves the rationality of limiting the addition amount to 2.0% in the claims; although excessive addition is beneficial to dispersion, it may bring electrochemical side effects.

[0056] 3. Comparative Example Analysis—Proving the Necessity of the Invention: Comparative Example 1 (No Polymer): Extremely wide particle size distribution (Span=3.04), poor battery performance. This clearly demonstrates that without the polymer of the present invention, the expected results cannot be achieved. Comparative Example 2 (Common Polymer PVP) and Comparative Example 3 (Small Molecule SDBS): Although the average particle size decreased, the Span value was greater than 2.5, resulting in poor battery performance. This proves that dispersants without a specific structure cannot achieve the core objectives of "precisely controlling particle size distribution" and "eliminating harmful fine powder." Comparative Example 4 (Excess Polymer): Although the particle size distribution was excellent, the ionic conductivity plummeted to 1.96 mS / cm, leading to deteriorated battery cycle performance. This clearly shows that excess polymer beyond the preferred range of the present invention severely hinders ion transport, thus proving the critical necessity of the content limit in the claims.

[0057] 4. The systematic comparison between the above embodiments and comparative examples fully demonstrates that only by using the specific structural interface-modified polymer described in this invention and controlling its dosage within the range of 0.1% to 2.0% can a sulfide solid electrolyte composite material simultaneously satisfy a series of stringent indicators such as "D10 > 0.3 μm, D50 0.8-1.0 μm, Span < 2.5". This material can significantly improve the electrochemical performance of all-solid-state batteries while maintaining high ionic conductivity.

[0058] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. A highly dispersed sulfide solid electrolyte composite material, characterized in that, It includes sulfide solid electrolyte particles and an interface-modified polymer that is at least partially coated on the periphery of the sulfide solid electrolyte particles; The interface-modified polymer is a functional polymer with an amphiphilic structure, which includes surface affinity segments that can specifically interact with the surface of the sulfide solid electrolyte particles, and spatially extended segments composed of polyether. The highly dispersible sulfide solid electrolyte composite material has a specific particle size distribution regulated by the interface-modified polymer, wherein the particle size distribution satisfies the following: average particle size D10 > 0.3 μm, median particle size D50 is 0.8 μm to 1.0 μm, D90 < 2.5 μm, and particle size distribution width Span = (D90-D10) / D50 < 2.

5.

2. The highly dispersed sulfide solid electrolyte composite material according to claim 1, characterized in that, The mass fraction of the interface-modified polymer is 0.1% to 2.0% based on the total mass of the composite material.

3. The highly dispersed sulfide solid electrolyte composite material according to claim 1, characterized in that, In the interface-modified polymer, the surface affinity segment includes at least one functional group selected from sulfonic acid group, phosphonic acid group, carboxyl group, thiol group, silanol group, and their ionic forms.

4. The highly dispersed sulfide solid electrolyte composite material according to claim 1, characterized in that, The functional groups contained in the surface affinity segments are configured to form coordination bonds or ion-dipole interactions with lithium ions, phosphorus atoms, or sulfur atoms on the surface of the sulfide solid electrolyte.

5. The highly dispersed sulfide solid electrolyte composite material according to claim 1, characterized in that, In the interface-modified polymer, the spatially extended segments are composed of polyethylene oxide segments, polypropylene oxide segments, or their random / block copolymers.

6. The highly dispersed sulfide solid electrolyte composite material according to claim 1, characterized in that, The interface-modified polymer has a block, graft, or comb-like molecular topology, wherein the surface affinity segments and the spatially extended segments are connected by covalent bonds. The number-average molecular weight Mn of the interface-modified polymer is 1000 to 10000 g / mol.

7. The highly dispersed sulfide solid electrolyte composite material according to claim 1, characterized in that, The sulfide solid electrolyte is selected from Li3PS4 and Li7P3S. 11 Li 10 GeP2S 12 Li6PS5Cl, and at least one glass, glass-ceramic or crystalline material from the Li2S-P2S5, Li2S-SiS2, and Li2S-B2S3 systems.

8. A method for preparing a highly dispersed sulfide solid electrolyte composite material according to any one of claims 1-7, characterized in that, Includes the following steps: The sintered sulfide solid electrolyte block, aprotic organic solvent, and interface-modified polymer were mixed and then subjected to wet crushing, followed by separation and drying.

9. An all-solid-state battery electrode, characterized in that, The composite material containing highly dispersed sulfide solid electrolytes as described in any one of claims 1-7.

10. An all-solid-state battery, characterized in that, Includes the all-solid-state battery electrode as described in claim 9.

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