Coated sulfide solid-state electrolyte, and preparation method and application thereof

Abstract

This application provides a coated sulfide solid electrolyte, its preparation method, and its application. The preparation method involves providing sulfide electrolyte powder and a coating agent solution. The sulfide electrolyte powder and coating agent solution are then subjected to a fluidized bed coating process, causing the coating agent solution to coat the surface of the sulfide electrolyte powder. Solvent removal is then performed to form a coating layer, resulting in a coated sulfide solid electrolyte. In this application, the coating layer isolates the sulfide solid electrolyte from air, improving its stability. Furthermore, the coating layer has a uniform thickness, and the coating agent is evenly distributed on the surface of the sulfide electrolyte, further enhancing its stability in air. The coated sulfide solid electrolyte prepared in this application can also further improve the conductivity of the sulfide solid electrolyte, maintaining good conductivity even when exposed to air, showing promising application prospects in sulfide all-solid-state batteries.

Description

Technical Field

[0001] This application relates to the field of solid electrolytes, and more specifically, to a coated sulfide solid electrolyte and its preparation method. Background Technology

[0002] With the rapid development of new energy technologies, all-solid-state batteries have become a research hotspot for next-generation high-efficiency energy storage devices due to their advantages such as high energy density, wide operating temperature range, and excellent safety. Among many solid electrolyte materials, sulfide solid electrolytes show broad application prospects due to their excellent mechanical properties and high ionic conductivity comparable to liquid electrolytes.

[0003] However, sulfide electrolytes suffer from severe air sensitivity, readily reacting with moisture in the environment, leading to material decomposition and a sharp drop in ionic conductivity. More importantly, this reaction generates highly toxic and corrosive hydrogen sulfide (H2S) gas, endangering not only the health of production personnel but also corroding production equipment, posing a significant challenge to large-scale production.

[0004] To address this issue, researchers have developed various methods to improve the air stability of sulfide electrolytes. Existing technologies utilize a process of "ball milling, drying, stirring and coating, secondary drying, sintering, and crushing" to prepare highly air-stable electrolyte materials. However, this method relies heavily on solution dispersion and mixing, resulting in relatively poor consistency; furthermore, the need for secondary high-temperature sintering limits the types of coating agents that can be used. Other researchers have obtained highly air-stable electrolyte materials by mixing solid electrolyte powder with solvents such as thiols, milling the mixture, and then vacuum drying. However, this method also fails to control the uniformity of the coating layer thickness.

[0005] In view of the above, this application is hereby submitted. Summary of the Invention

[0006] The main objective of this application is to provide a coated sulfide solid electrolyte and its preparation method, so as to solve the problems of poor air stability of sulfide electrolytes in the prior art, and the uneven coating thickness of the coating layer when the coating agent is coated on the surface of the sulfide electrolyte by traditional ball milling or sand milling, resulting in uneven distribution of the coating agent on the surface of the sulfide electrolyte.

[0007] To achieve the above objectives, according to the first aspect of this application, a method for preparing a coated sulfide solid electrolyte is provided. The method includes: providing sulfide electrolyte powder and a coating agent solution; subjecting the sulfide electrolyte powder and the coating agent solution to a fluidized bed coating process, such that the coating agent solution coats the surface of the sulfide electrolyte powder, removes the solvent to form a coating layer, and obtains a coated sulfide solid electrolyte.

[0008] Furthermore, the mass content of the coating agent in the coating agent solution is 0.1-5%.

[0009] Furthermore, the coating agent in the coating agent solution is selected from at least one of 1-undecylthiol, aluminum trifluoromethanesulfonate, and sodium trifluoromethanesulfonate.

[0010] Furthermore, the solvent in the coating agent solution is selected from at least one of benzene, toluene, xylene, and dimethylacetamide.

[0011] Furthermore, the particle size D50 of the sulfide electrolyte powder is 1~20μm.

[0012] Furthermore, the thickness of the coating layer is 0.1~10nm.

[0013] Furthermore, during the coating process, the feed rate of the sulfide electrolyte powder is 30~250 g / min; the feed rate of the coating agent solution is 0.5~30 mL / min.

[0014] Furthermore, the mass ratio of the coating agent to the sulfide electrolyte powder in the coating agent solution is (0.06~1.0):100.

[0015] Furthermore, the coating treatment temperature is 25~120℃, and the coating treatment time is 5~90min.

[0016] Furthermore, the preparation method of sulfide electrolyte powder includes: weighing lithium source, sulfur source, phosphorus source, halogen source and optionally doped metal source according to stoichiometric ratio, mixing and sintering, and then crushing to obtain the sulfide electrolyte powder.

[0017] Furthermore, the sulfide electrolyte powder is selected from Li 5.4 PS 4.4 Cl 1.6 Li 5.4 PS 4.4 ClBr 0.6 Li 5.5 PS 4.5 Cl 0.8 Br 0.7 Li 4.8 PS 4.4 I, Li 3.8 Sn 0.2 P 0.8 S 4.4 At least one of them.

[0018] Furthermore, the sintering temperature of the sulfide electrolyte powder is 400℃~600℃, and the sintering time is 10~15h.

[0019] To achieve the above objectives, according to a second aspect of this application, a coated sulfide solid electrolyte is provided, which is obtained according to the preparation method provided in the first aspect of this application.

[0020] According to a third aspect of this application, a sulfide all-solid-state battery is provided, comprising a positive electrode, a solid electrolyte, and a negative electrode, wherein the solid electrolyte is obtained by the preparation method provided in the first aspect of this application or is a coated sulfide solid electrolyte provided in the second aspect of this application.

[0021] By applying the technical solution of this application, sulfide electrolyte powder and coating agent solution are coated in a fluidized bed, forming a coating layer on the surface of the sulfide electrolyte powder, thus obtaining a coated sulfide solid electrolyte. This coating layer isolates the sulfide solid electrolyte from air, improving its stability. Furthermore, the prepared coated sulfide solid electrolyte has a uniform coating layer thickness, with the coating agent evenly distributed on the surface, further enhancing its stability in air. The coated sulfide solid electrolyte prepared in this application can also further improve the conductivity of the sulfide solid electrolyte, maintaining good conductivity even when exposed to air, showing promising application prospects in sulfide all-solid-state batteries. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0023] Figure 1 A schematic diagram of the preparation of a coated sulfide solid electrolyte according to Example 1 of this application is shown. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0025] As described in the background section of this application, existing technologies suffer from poor conductivity and inconsistent coating thickness in coated sulfide solid electrolytes. To address these issues, this application provides a sulfide solid electrolyte, its preparation method, and its applications.

[0026] In a first typical embodiment of this application, a method for preparing a coated sulfide solid electrolyte is provided. The method includes: providing sulfide electrolyte powder and a coating agent solution, and subjecting the sulfide electrolyte powder and the coating agent solution to a fluidized bed coating process, so that the coating agent solution coats the surface of the sulfide electrolyte powder to form a coating layer, thereby obtaining a coated sulfide solid electrolyte.

[0027] In this application, sulfide electrolyte powder is fluidized to form a flowing state of sulfide electrolyte powder. A coating agent solution is then sprayed onto the surface of the flowing sulfide electrolyte powder, causing the coating agent solvent to coat the surface of the sulfide electrolyte powder. The solvent is then removed to form a coating layer, resulting in a coated sulfide solid electrolyte. This coating layer isolates the sulfide solid electrolyte from air, further improving its stability. Furthermore, the prepared coated sulfide solid electrolyte has a uniform coating layer thickness, with the coating agent evenly distributed on the sulfide electrolyte surface. The coated sulfide solid electrolyte prepared in this application not only has further improved conductivity but also maintains good conductivity even when exposed to air, showing promising application prospects in sulfide all-solid-state batteries.

[0028] In some embodiments, the mass content of the coating agent in the coating agent solution is 0.1% to 5%. An appropriate amount of coating agent in the coating agent solution is more conducive to controlling the uniformity of the coating layer thickness during the coating process. This ensures that the coating layer is neither too thin, which would degrade its air-insulating performance, nor too thick, which would affect the ionic conductivity of the sulfide solid electrolyte. Specifically, the mass content of the coating agent in the coating agent solution is any value from 0.1%, 0.5%, 1%, 2%, 3%, 4%, and 5%, or a range between any two.

[0029] In some specific embodiments, the coating agent in the coating agent solution is a commonly used coating agent in the art, including but not limited to any one or more of 1-undecylthiol, aluminum trifluoromethanesulfonate, sodium trifluoromethanesulfonate, and pentafluorophenylboron.

[0030] In some specific embodiments, the solvent in the coating agent solution is selected from any one or more of benzene, toluene, xylene, and dimethylacetamide.

[0031] In some embodiments, the particle size D50 of the sulfide electrolyte powder is 0~20μm. A suitable particle size of the sulfide electrolyte powder is beneficial for improving the flowability of the material during the fluidized bed coating process, and also enables the coating agent to uniformly coat the surface of the electrolyte powder to form a coating layer with a more uniform thickness. Specifically, the particle size D50 of the sulfide electrolyte powder is any value or a range between 1μm, 2μm, 3μm, 4μm, 5μm, 10μm, 15μm, and 20μm.

[0032] In some embodiments, the coating layer thickness is 0.1~10 nm to further improve the air stability of the coated sulfide solid electrolyte. Through fluidized bed coating technology, the coating agent solution directly contacts the sulfide electrolyte powder in a flowing, suspended state via an airflow. Combined with the high-temperature drying process of the carrier gas, rapid solidification of the coating agent on the powder surface is achieved, greatly improving coating efficiency and effectiveness. Controlling the coating layer thickness between 0.1~10 nm effectively isolates the electrolyte from air while maintaining high ionic conductivity. Specifically, the coating layer thickness is any value from 0.1 nm, 0.5 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, and 10 nm, or a range between any two.

[0033] To ensure sufficient contact and uniform coating between the sulfide electrolyte powder and the coating agent solution within the fluidized bed, in some embodiments, the feed rate of the sulfide electrolyte powder is 30–250 g / min, and the feed rate of the coating agent solution is 0.5–30 mL / min during the coating process. Specifically, the feed rate of the sulfide electrolyte powder is any value or a range between 30 g / min, 50 g / min, 100 g / min, 150 g / min, 200 g / min, and 250 g / min; the feed rate of the coating agent solution is any value or a range between 0.5 mL / min, 1 mL / min, 5 mL / min, 10 mL / min, 15 mL / min, 20 mL / min, 25 mL / min, and 30 mL / min.

[0034] To further improve the coating effect of sulfide electrolyte in the coating layer, in some embodiments, the mass ratio of the coating agent to the sulfide electrolyte powder in the coating agent solution is (0.06~1.0):100. Specifically, the mass ratio of the coating agent to the sulfide electrolyte powder in the coating agent solution is any value or a range between 0.06:100, 0.092:100, 0.1:100, 0.15:100, 0.172:100, 0.2:100, 0.5:100, 0.8:100, and 1.0:100.

[0035] To further and effectively cure the coating agent in the coating agent solution and effectively evaporate the solvent, in some embodiments, the coating treatment temperature is 25~120℃, and the coating treatment time is 5~90min. Specifically, the coating treatment temperature is any value or a range between any two of 25℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, and 120℃, and the coating treatment time is any value or a range between any two of 5min, 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, and 90min.

[0036] To further optimize the preparation efficiency of sulfide electrolytes, in some embodiments, the preparation method of sulfide electrolyte powder includes: weighing lithium source, sulfur source, phosphorus source, halogen source, and optionally doped metal source according to stoichiometric ratio, mixing and sintering, followed by crushing to obtain sulfide electrolyte powder. Specifically, the halogen element is any one or more of fluorine, chlorine, bromine, and iodine, and the doped metal source is any one or more of Sn, Ge, Cu, Bi, Sb, Zr, Cd, V, and Cr.

[0037] By controlling the sintering temperature and sintering time, the microstructure and particle size distribution of the sulfide electrolyte can be further optimized. In some embodiments, the sintering temperature of the sulfide electrolyte powder is 400℃~600℃, and the sintering time is 10~15h. Specifically, the sintering temperature is any value or a range between any two of 400℃, 420℃, 440℃, 460℃, 480℃, 500℃, 520℃, 540℃, 560℃, 580℃, and 600℃; the sintering time is any value or a range between any two of 10h, 11h, 12h, 13h, 14h, and 15h.

[0038] In some specific embodiments, the sulfide electrolyte is selected from Li 5.4 PS 4.4 Cl 1.6 Li 5.4 PS 4.4 ClBr 0.6 Li 5.5 PS 4.5 Cl 0.8 Br 0.7 Li 4.8 PS 4.4 I, Li 3.8 Sn 0.2 P 0.8 S 4.4 Any one or more of the following.

[0039] In a second typical embodiment of this application, a coated sulfide solid electrolyte is provided, which is prepared by the first typical embodiment.

[0040] In this application, a coated sulfide solid electrolyte is obtained by coating sulfide electrolyte powder with a coating agent solution in a fluidized bed. The coating agent solution coats the surface of the sulfide electrolyte powder to form a coating layer. The coated sulfide solid electrolyte prepared in this application not only further improves conductivity but also maintains good conductivity when exposed to air.

[0041] In a third typical embodiment of this application, a sulfide all-solid-state battery is provided, which includes a positive electrode, a solid electrolyte and a negative electrode, wherein the solid electrolyte is a sulfide solid electrolyte prepared by the preparation method provided in the first typical embodiment or a sulfide solid electrolyte provided in the second typical embodiment.

[0042] The coated sulfide solid electrolyte provided in this application employs fluidized bed coating technology to form a coating layer on the electrolyte surface. This technology utilizes airflow to keep the sulfide solid electrolyte powder in a flowing state, and by spraying in a coating agent solution, uniform distribution and thickness control of the coating agent on the electrolyte surface are achieved. This process further avoids direct contact between the sulfide electrolyte and air, effectively improving the electrolyte's air and water stability. Simultaneously, the amount of coating agent used in the coating process is relatively small, and the solvent treatment process is relatively simple, making it more environmentally friendly. Compared with traditional coating methods, fluidized bed coating technology simplifies the process flow and is more suitable for efficient and continuous production, thus significantly improving the preparation efficiency and quality stability of the sulfide solid electrolyte. Furthermore, by controlling the mass ratio of the coating amount and the coating temperature, the formation of the coating layer can be further optimized, ensuring its tight bonding with the sulfide solid electrolyte, thereby significantly improving the material's air stability while maintaining excellent ionic conductivity. This technical solution effectively solves the air sensitivity problem of sulfide electrolytes, providing technical support for the widespread application and large-scale production of all-solid-state batteries.

[0043] The beneficial effects of this application will be further illustrated below with reference to embodiments and comparative examples.

[0044] Example 1

[0045] This embodiment provides a coated sulfide solid electrolyte, and the preparation process is illustrated in the diagram below. Figure 1 As shown, its preparation method includes:

[0046] (1) Li₂S, P₂S₅, LiCl and LiBr were mixed in a high-speed mixer at a molar ratio of 3.8:1:2.0:1.2 to obtain a mixture. The mixture was sintered at 450℃ for 12 h, and then crushed by an air jet mill to obtain sulfide solid electrolyte powder Li. 5.4 PS 4.4 ClBr 0.6 The particle size D50 of the sulfide electrolyte powder is 2 μm.

[0047] (2) 1-Undecylthiol was dissolved in xylene solvent at a mass content of 1% to obtain a coating agent solution. The sulfide electrolyte powder was fed into the fluidized bed coating machine at a feed rate of 50 g / min and the coating agent solution was fed at a liquid rate of 5 mL / min for coating treatment. The mass ratio of coating agent to sulfide electrolyte powder was controlled at 0.086:100 to obtain a coated sulfide solid electrolyte. The coating treatment temperature was 80℃ and the coating treatment time was 10 min.

[0048] Example 2

[0049] The difference between this embodiment and Example 1 is that in step (1), the mixture is mixed in a molar ratio of 1.9:0.5:1.6 for Li2S, P2S5 and LiCl.

[0050] Example 3

[0051] The difference between this embodiment and embodiment 1 is that in step (2), the mass ratio of the coating agent to the sulfide electrolyte powder is adjusted to 0.062:100.

[0052] Example 4

[0053] The difference between this embodiment and embodiment 1 is that in step (2), the coating treatment time is adjusted to 30 minutes.

[0054] Example 5

[0055] The difference between this embodiment and embodiment 4 is that in step (2), 1-undecylthiol is dissolved in xylene solvent at a mass content of 3%.

[0056] Example 6

[0057] The difference between this embodiment and embodiment 1 is that in step (2), the coating treatment temperature is adjusted to 100°C.

[0058] Example 7

[0059] The difference between this embodiment and Example 1 is that in step (1), the mixture is adjusted to be mixed in a molar ratio of 4:1:1.6:1.4 for Li2S, P2S5, LiCl and LiBr.

[0060] Example 8

[0061] The difference between this embodiment and embodiment 1 is that in step (2), the coating treatment time is adjusted to 5 minutes.

[0062] Example 9

[0063] The difference between this embodiment and embodiment 1 is that in step (2), the coating treatment time is adjusted to 60 minutes.

[0064] Example 10

[0065] The difference between this embodiment and embodiment 4 is that in step (2), 1-undecylthiol is dissolved in xylene solvent at a mass content of 5%.

[0066] Example 11

[0067] The difference between this embodiment and embodiment 1 is that in step (2), the feeding rate of the sulfide electrolyte powder is 30 g / min, the feeding rate of the coating agent solution is 0.5 mL / min, and the mass ratio of the coating agent to the sulfide electrolyte powder is controlled to be 0.086:100.

[0068] Example 12

[0069] The difference between this embodiment and embodiment 1 is that in step (2), the feeding rate of the sulfide electrolyte powder is 250 g / min, the feeding rate of the coating agent solution is 30.0 mL / min, and the mass ratio of the coating agent to the sulfide electrolyte powder is controlled to be 1.0:100.

[0070] Example 13

[0071] The difference between this embodiment and embodiment 1 is that in step (2), the feeding rate of the sulfide electrolyte powder is adjusted to 10 g / min, the feeding rate of the coating agent solution is 0.2 mL / min, and the mass ratio of the coating agent to the sulfide electrolyte powder is controlled to be 0.0001:100.

[0072] Example 14

[0073] The difference between this embodiment and embodiment 1 is that in step (2), the feeding rate of the sulfide electrolyte powder is adjusted to 300 g / min, the feeding rate of the coating agent solution is 35 mL / min, and the mass ratio of the coating agent to the sulfide electrolyte powder is controlled to be 1.5:100.

[0074] Example 15

[0075] The difference between this embodiment and embodiment 1 is that in step (2), the coating treatment temperature is adjusted to 15°C and the coating treatment time is 5 min.

[0076] Example 16

[0077] The difference between this embodiment and embodiment 1 is that in step (2), the coating treatment temperature is adjusted to 140°C and the coating treatment time is 100 min.

[0078] Example 17

[0079] The difference between this embodiment and Example 1 is that in step (2), 1-undecylthiol is dissolved in xylene solvent at a mass content of 0.05%.

[0080] Example 18

[0081] The difference between this embodiment and Example 1 is that in step (2), 1-undecylthiol is dissolved in xylene solvent at a mass content of 10%.

[0082] Comparative Example 1

[0083] The difference between this comparative example and Example 1 is that the sulfide solid electrolyte powder and the coating agent solution were mixed and stirred for 4 hours and then dried at 80°C for 12 hours.

[0084] Comparative Example 2

[0085] The difference between this comparative example and Example 1 is that the sulfide solid electrolyte powder and the coating agent solution are mixed and stirred in a sand mill.

[0086] Experimental Example 1

[0087] The sulfide solid electrolytes prepared in Examples 1-18 and Comparative Examples 1-2 were subjected to ionic conductivity tests, conductivity retention tests, and coating layer thickness tests.

[0088] The specific testing method is as follows:

[0089] (1) Ionic conductivity testing method:

[0090] Weigh 200 mg of electrolyte using an analytical balance; slowly pour the weighed electrolyte into and spread it evenly in the mold sleeve, assemble the gasket and upper pressure head; place the mold in the center of the tablet press table, loosen the oil injection screw, tighten the oil drain valve rod clockwise, and pressurize at a uniform speed to 4~4.1 tons, holding the pressure for 10 minutes; manually assemble the clamp and mold battery, manually tighten the three screws, and use a torque wrench to fix the screws with a force of 15 Nm. Subsequently, the ionic conductivity was tested using electrochemical impedance spectroscopy (EIS) in the frequency range of 1 Hz~1 MHz with an AC perturbation of 10 mV, and the conductivity of the electrolyte was calculated based on the real part of the impedance.

[0091] (2) Calculation method for conductivity retention rate: Ionic conductivity 24h after exposure / Ionic conductivity before exposure × 100%.

[0092] (3) Test method for coating thickness: Refer to GB / T 20018-2005.

[0093] The test results are shown in Table 1.

[0094] Table 1

[0095]

[0096] As can be seen from the comparison between Examples 1-18 and Comparative Examples 1-2, in Examples 1-18, the sulfide electrolyte powder and the coating agent solution are coated by a fluidized bed, so that the coating agent solution forms a coating layer on the surface of the sulfide electrolyte powder, and a coated sulfide solid electrolyte is obtained. This not only isolates the sulfide solid electrolyte from contact with air and improves the stability of the sulfide electrolyte, but also the coating layer of the prepared coated sulfide solid electrolyte has a uniform thickness, which can further improve the conductivity of the sulfide solid electrolyte and maintain good conductivity when exposed to air.

[0097] Comparing Examples 1 and 11-14, it can be seen that by controlling the feed rate of the sulfide electrolyte powder and the inlet rate of the coating agent solution during the coating process, the coating layer formed by the coating agent solution on the surface of the sulfide electrolyte powder can be made uniform in thickness, neither too thick nor too thin, and the conductivity of the sulfide solid electrolyte can be improved, maintaining good conductivity even when exposed to air. In Example 14, due to the thicker coating layer, the coated sulfide solid electrolyte has better stability when exposed to air, but its ionic conductivity is poor.

[0098] As can be seen from the comparison of Examples 1, 4, 8-9, and 15-16, by controlling the temperature and time of the coating treatment, the coating layer thickness of the coated sulfide solid electrolyte obtained by fluidized bed coating treatment can be made more uniform, thereby improving the conductivity of the sulfide solid electrolyte and maintaining good conductivity even when exposed to air. In Example 15, the coating temperature was too low, resulting in a poor coating effect, which in turn led to lower conductivity of the coated solid electrolyte and poor stability when exposed to air.

[0099] As can be seen from the comparison of Examples 1, 5, 10 and 17-18, by adjusting the mass content of the coating agent in the coating agent solution, the coating layer thickness of the coated sulfide solid electrolyte can be made more uniform, thereby improving the conductivity of the sulfide solid electrolyte, and maintaining good conductivity even when exposed to air.

[0100] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0101] In this application, sulfide electrolyte powder and a coating agent solution are coated using a fluidized bed process. The coating agent solution forms a coating layer on the surface of the sulfide electrolyte powder, resulting in a coated sulfide solid electrolyte. This coating layer isolates the sulfide solid electrolyte from air, improving its stability. Furthermore, the prepared coated sulfide solid electrolyte exhibits a uniform coating layer thickness, with the coating agent evenly distributed on the surface, further enhancing its stability in air. The coated sulfide solid electrolyte prepared in this application also further improves the conductivity of the sulfide solid electrolyte, maintaining good conductivity even when exposed to air, demonstrating promising application prospects in sulfide all-solid-state batteries.

[0102] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a coated sulfide solid electrolyte, characterized in that, The preparation method includes: A sulfide electrolyte powder and a coating agent solution are provided. The sulfide electrolyte powder and the coating agent solution are subjected to a fluidized bed coating process, so that the coating agent solution coats the surface of the sulfide electrolyte powder, and the solvent is removed to form a coating layer, thereby obtaining the coated sulfide solid electrolyte.

2. The preparation method according to claim 1, characterized in that, The coating agent solution contains 0.1% to 5% by mass.

3. The preparation method according to claim 1, characterized in that, The coating agent in the coating agent solution is selected from at least one of 1-undecyl mercaptan, aluminum trifluoromethanesulfonate, and sodium trifluoromethanesulfonate. And / or, the solvent in the coating agent solution is selected from at least one of benzene, toluene, xylene, and dimethylacetamide.

4. The preparation method according to claim 1, characterized in that, The particle size D50 of the sulfide electrolyte powder is 1~20μm; And / or, the thickness of the coating layer is 0.1~10nm.

5. The preparation method according to claim 1, characterized in that, During the coating process, the feed rate of the sulfide electrolyte powder is 30~250 g / min; the feed rate of the coating agent solution is 0.5~30 mL / min. And / or, the mass ratio of the coating agent in the coating agent solution to the sulfide electrolyte powder is (0.06~1.0):

100.

6. The preparation method according to claim 1, characterized in that, The coating treatment temperature is 25~120℃, and the coating treatment time is 5~90min.

7. The preparation method according to claim 1, characterized in that, The preparation method of the sulfide electrolyte powder includes: weighing lithium source, sulfur source, phosphorus source, halogen source and optionally doped metal source according to stoichiometric ratio, mixing them and sintering them, and then crushing them to obtain the sulfide electrolyte powder. Preferably, the sulfide electrolyte powder is selected from Li 5.4 PS 4.4 Cl 1.6 Li 5.4 PS 4.4 ClBr 0.6 Li 5.5 PS 4.5 Cl 0.8 Br 0.7 Li 4.8 PS 4.4 I, Li 3.8 Sn 0.2 P 0.8 S 4.4 At least one of them.

8. The preparation method according to claim 7, characterized in that, The sintering temperature of the sulfide electrolyte powder is 400℃~600℃, and the sintering time is 10~15h.

9. A coated sulfide solid electrolyte, characterized in that, The coated sulfide solid electrolyte is obtained by the preparation method according to any one of claims 1 to 8.

10. A sulfide all-solid-state battery, characterized in that, The sulfide all-solid-state battery includes a positive electrode, a solid electrolyte, and a negative electrode, wherein the solid electrolyte is the coated sulfide solid electrolyte obtained by the preparation method of the sulfide solid electrolyte according to any one of claims 1 to 8 or the coated sulfide solid electrolyte according to claim 9.

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