Sulfide solid-state electrolyte and preparation method therefor, battery, and electric device

Abstract

A sulfide solid-state electrolyte and a preparation method therefor, a battery, and an electric device, relating to the field of batteries. The sulfide solid-state electrolyte comprises halogen. In a crystal structure of the sulfide solid-state electrolyte, the proportion of halogen atoms occupying a Wyckoff 4d site relative to the total number of halogen atoms in the sulfide electrolyte is 0.20 to 0.40. In the present application, the proportion of the halogen atoms occupying the Wyckoff 4d site in the sulfide solid-state electrolyte relative to the total number of the halogen atoms in the sulfide electrolyte is controlled to be greater than or equal to 0.2 and less than or equal to 0.4, thereby improving the ionic conductivity of the sulfide solid-state electrolyte.

Description

Sulfide solid electrolytes and their preparation methods, batteries and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 202510494609.7, filed on April 18, 2025, entitled "Sulfide Solid Electrolyte and Preparation Method Thereof, Battery and Electrical Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of batteries, specifically to a sulfide solid electrolyte and its preparation method, as well as batteries and electrical devices. Background Technology

[0003] Solid-state electrolytes are a potential alternative to liquid electrolytes in lithium-ion batteries, offering the potential to improve battery safety and energy density. Among them, sulfide solid-state electrolytes have attracted widespread attention due to their excellent ionic conductivity and energy density. However, the chemical instability of sulfide solid-state electrolytes to air and their poor compatibility with solvents and binders are significant factors hindering their industrial application. Furthermore, improving the ionic conductivity of sulfide solid-state electrolytes is also a crucial issue in the development of all-solid-state batteries. Summary of the Invention

[0004] This application provides a sulfide solid electrolyte, its preparation method, battery, and electrical device, which can improve the ionic conductivity of the sulfide solid electrolyte.

[0005] The first aspect of this application provides a sulfide solid electrolyte containing halogens. In the crystal structure of the sulfide solid electrolyte, the number of halogen atoms occupying the 4d Wyckoff position accounts for 0.20-0.40% of the total number of halogen atoms in the sulfide solid electrolyte.

[0006] In one specific embodiment, the sulfide solid electrolyte includes doped or undoped lithium phosphorus sulfide chloride solid electrolyte.

[0007] In one specific embodiment, the molecular formula of the sulfide solid electrolyte is Li. 6-x PS 5-x-y O y Cl 1+x-z Br z , where 0.0≤x≤0.7, 0.0≤y≤0.3, 0.0≤z≤0.7, and x and z are not both zero.

[0008] The second aspect of this application provides a method for preparing a sulfide solid electrolyte, which is used to prepare the sulfide solid electrolyte as described above. The preparation method includes: mixing raw materials for preparing the sulfide solid electrolyte in a stoichiometric ratio and then sintering them to obtain the sulfide solid electrolyte.

[0009] In one specific embodiment, the raw materials are mixed according to the stoichiometric ratio and then ball-milled to obtain a precursor; the precursor is cold-pressed into precursor particles; the precursor particles are sintered, cooled, and ball-milled to obtain a sulfide solid electrolyte.

[0010] The preparation method described above uses raw materials including LiCl, Li2S, and P2S5.

[0011] The preparation method described above also includes LiBr and / or Li2O as raw materials.

[0012] In the preparation method described above, after the precursor particles are sintered and cooled, the ball milling process involves a ball milling speed of 300 r / min to 1000 r / min and a ball milling time of 25 h to 50 h.

[0013] In the preparation method described above, the sintering temperature is 100℃-800℃ and the sintering time is 1h-30h.

[0014] In the preparation method described above, the preparation process of the sulfide solid electrolyte is carried out in an inert atmosphere, and the water pressure and oxygen partial pressure are both less than 0.1 ppm throughout the entire preparation process.

[0015] A third aspect of this application provides a solid-state battery, including a sulfide solid electrolyte as described above, or a sulfide solid electrolyte prepared by the preparation method described above.

[0016] The solid-state battery as described above includes a positive electrode, a negative electrode, and a solid electrolyte membrane disposed between the positive electrode and the negative electrode. At least one of the positive electrode, the negative electrode, and the solid electrolyte membrane is a sulfide solid electrolyte as described above or a sulfide solid electrolyte prepared by the preparation method described above.

[0017] The solid-state battery described above is an all-solid-state battery.

[0018] A fourth aspect of this application provides a battery assembly comprising one or more solid-state batteries as described above.

[0019] The fifth aspect of this application provides an electrical device that includes a solid-state battery as described above, or a battery assembly as described above.

[0020] The implementation of this application has at least the following beneficial effects:

[0021] This application can significantly improve the disorder within the crystal of sulfide solid electrolytes, thereby increasing the lithium-ion intercage jumping rate of sulfide solid electrolytes, reducing the lithium-ion migration energy barrier, and improving the ionic conductivity of sulfide solid electrolytes. Attached Figure Description

[0022] Figure 1 is a schematic diagram of a battery assembly provided in this application;

[0023] Figure 2 is a structural schematic diagram of an electrical device provided in this application.

[0024] Explanation of reference numerals in the attached diagram: 1-Solid-state battery; 2-Battery module; 3-Electrical equipment. Detailed Implementation

[0025] To enable those skilled in the art to better understand the solutions of this application, a further detailed description of this application is provided below. The specific embodiments listed below are merely descriptions of the principles and features of this application; the examples are only for explaining this application and are not intended to limit its scope. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0026] Sulfide solid electrolytes readily react with oxygen and water in the air, leading to irreversible degradation of their ionic conductivity and the generation of large amounts of toxic gases such as H2S. This is mainly because the chemical bond energy of polystyrene (PS) is much lower than that of porosilicate (PO), making the PS structure more susceptible to oxidation or desulfurization. This results in irreversible chemical reactions with oxygen and water vapor in the air, causing changes in the structure of the sulfide solid electrolyte and a decrease in its ionic conductivity.

[0027] In related technologies, on the one hand, co-doping of O and C elements into sulfide solid electrolytes can improve their air stability, but it does not further enhance their ionic conductivity. Simultaneously, carbon materials may undergo side reactions with the sulfide solid electrolyte or the corresponding cathode material in all-solid-state batteries under high voltage, leading to a decrease in the chemical stability of the sulfide solid electrolyte and potentially causing capacity loss and shortened lifespan in the corresponding all-solid-state batteries. On the other hand, multi-element doping methods have been used to construct multi-cation-doped halide solid electrolyte materials or multi-anion-doped halide solid electrolyte materials. Due to the introduction of internal structural and chemical disorder from multi-element doping, this method can improve the ionic conductivity of sulfide solid electrolytes, but it also results in brittleness and easy breakage, limiting its reliability and durability in practical applications.

[0028] Based on the technical problems existing in related technologies, the embodiments of this application achieve the following: in the crystal structure of the sulfide solid electrolyte, the total number of halogens occupying the 4d position of the Wyckoff position in the refined X-ray diffraction pattern is greater than or equal to 0.2 and less than or equal to 0.4 of the total number of halogen atoms in the sulfide solid electrolyte. This method uses readily available and inexpensive raw materials, has a simple manufacturing process, and can improve the ionic conductivity of the sulfide solid electrolyte, thereby optimizing the performance of the sulfide solid electrolyte.

[0029] This application provides a sulfide solid electrolyte containing halogens. In the crystal structure of the sulfide solid electrolyte, the number of halogen atoms occupying the 4d Wyckoff position accounts for 0.20-0.40% of the total number of halogen atoms in the sulfide electrolyte.

[0030] For example, in the crystal structure of a sulfide solid electrolyte, the proportion of halogen atoms occupying the 4d Wyckoff position to the total number of halogen atoms in the sulfide electrolyte can be 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, or any combination thereof.

[0031] For example, in the crystal structure of a sulfide solid electrolyte, the proportion of halogen atoms occupying the 4d Wyckoff position to the total number of halogen atoms in the sulfide electrolyte can be obtained in the following way:

[0032] Step 1: Obtain the XRD diffraction pattern of the sulfide solid electrolyte using an XRD diffractometer. The sulfide solid electrolyte material powder sample is uniformly dispersed on the surface of an optical glass plate, and the measurement parameters are adjusted to achieve an X-ray scanning depth of 5 μm-15 μm.

[0033] Test method: incident angle 5°-7°, working voltage 40kV-50kV, working current 30mA-40mA, scanning range 5°~120°, step size 0.01°-0.02°.

[0034] Step 2: Fit the measured XRD diffraction pattern data using Rietveld refinement, including fine-tuning a series of parameters:

[0035] 1) Adjust the scale factor to match the overall intensity of the calculated and observed data;

[0036] 2) Adjust the background by using linear interpolation to adapt to intensity changes;

[0037] 3) Adjust the peak shape and use the pseudo-Voigt function to handle the peak broadening problem;

[0038] 4) Adjust the unit cell parameters and atomic coordinates to determine the lattice size and atomic positions;

[0039] 5) Adjust the fractional occupancy and thermal vibration parameters (Uiso) to describe stoichiometry and atomic dynamics. Based on the above fine-tuning of a series of parameters, the occupancy and content of various elements in the sample are quantitatively analyzed to obtain the proportion of halogen atoms occupying the 4d Wyckoff position in the refined X-ray diffraction pattern to the total number of halogen atoms in the sulfide electrolyte.

[0040] It is understood that, in the embodiments of this application, the disorder of sulfide solid electrolytes (such as LiPSCl) is increased by changing the occupancy number of specific sites in the crystal structure of the sulfide solid electrolyte, thereby enhancing the ionic conductivity of the sulfide solid electrolyte material. By making the proportion of halogen atoms occupying the 4d Wyckoff position in the sulfide solid electrolyte within the range of 0.20 to 0.40 of the total number of halogen atoms in the sulfide solid electrolyte, the disorder of the sulfide solid electrolyte structure can be significantly enhanced. This increase in disorder is crucial to the performance of the sulfide solid electrolyte. The disorder within the sulfide solid electrolyte crystal, by increasing the randomness of ion positions and paths, can reduce the potential barrier encountered by lithium ions during migration, thereby improving the ionic conductivity of the sulfide solid electrolyte material. By adjusting the proportion of halogen atoms occupying the 4d Wyckoff position in the sulfide solid electrolyte to within the range of 0.20 to 0.40 of the total number of halogen atoms in the sulfide solid electrolyte, lattice distortion and chemical stress are introduced, further enhancing the random distribution of atomic positions and potential site substitutions, thereby creating a more complex potential energy surface. This change results in more diverse lithium-ion migration channels, improving the overall conductivity of the sulfide solid electrolyte.

[0041] It is understood that the sulfide solid electrolyte provided in this application embodiment, without introducing any metal elements other than lithium into the lithium phosphorus sulfide chloride (LiPSCl) sulfide solid electrolyte material, enhances the disorder within the crystal lattice. This increased disorder provides the sulfide solid electrolyte with richer migration channels and new low-energy diffusion paths, thereby enhancing the overall mobility of lithium ions. Consequently, it increases the intercage jumping rate of lithium ions in the sulfide solid electrolyte, lowers the lithium ion migration energy barrier of the sulfide solid electrolyte, and improves the conductivity of the sulfide solid electrolyte ions.

[0042] In this embodiment of the application, by precisely controlling the proportion of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte to the total number of halogen atoms in the sulfide solid electrolyte to 0.20-0.40, the disorder inside the crystal of the sulfide solid electrolyte can be significantly improved, thereby increasing the lithium-ion intercage jumping rate of the sulfide solid electrolyte, reducing the lithium-ion migration energy barrier, and improving the ionic conductivity of the sulfide solid electrolyte.

[0043] In one specific embodiment, the sulfide solid electrolyte includes doped or undoped lithium phosphorus sulfide chloride solid electrolyte.

[0044] For example, the doped lithium phosphorus sulfide chloride solid electrolyte can be a lithium phosphorus sulfide chloride solid electrolyte doped with halogens, such as chlorine (Cl) and / or bromine (Br). For example, chlorine (Cl) is doped into the lithium phosphorus sulfide chloride solid electrolyte, or bromine (Br) is doped into the lithium phosphorus sulfide chloride solid electrolyte, or both chlorine (Cl) and bromine (Br) are doped into the lithium phosphorus sulfide chloride solid electrolyte.

[0045] Alternatively, the doped lithium phosphorus sulfide chloride solid electrolyte can also be a lithium phosphorus sulfide chloride solid electrolyte doped with halogens and oxygen. For example, chlorine (Cl) and oxygen (O) can be doped into the lithium phosphorus sulfide chloride solid electrolyte, or bromine (Br) and oxygen (O) can be doped into the lithium phosphorus sulfide chloride solid electrolyte, or chlorine (Cl), bromine (Br) and oxygen (O) can be doped into the lithium phosphorus sulfide chloride solid electrolyte.

[0046] In one specific embodiment, the molecular formula of the sulfide solid electrolyte is Li. 6-x PS 5-x-y O y Cl 1+x-z Br z , where 0.0≤x≤0.7, 0.0≤y≤0.3, 0.0≤z≤0.7, and x and z are not both zero.

[0047] For example, the value of x can be 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or a range of any two of them.

[0048] For example, the value of y can be a range of 0.0, 0.1, 0.2, 0.3, or any two of them.

[0049] For example, the value of z can be a range of 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or any combination thereof.

[0050] For example, when x is 0, y is 0, and z is not 0, the sulfide solid electrolyte provided in this application embodiment is a solid electrolyte material based on lithium phosphorus sulfide chloride (LiPSCl) sulfide solid electrolyte doped with bromine; when x is not 0, y is 0, and z is 0, the halide solid electrolyte provided in this application embodiment is a solid electrolyte material based on lithium phosphorus sulfide chloride (LiPSCl) sulfide solid electrolyte doped with chlorine; when x is not 0, y is not 0, and z is not 0, the halide solid electrolyte provided in this application embodiment is a solid electrolyte material based on lithium phosphorus sulfide chloride (LiPSCl) sulfide solid electrolyte doped with chlorine, oxygen, and bromine.

[0051] It should be noted that the Li provided in the embodiments of this application 6-x PS 5-x-y O y Cl 1+x-z Br z In the sulfide solid electrolyte, the values ​​of 0.0≤x≤0.7, 0.0≤y≤0.3, and 0.0≤z≤0.7 are only some examples, and this application does not limit them. As long as the total number of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte is greater than or equal to 0.20 and less than or equal to 0.40 of the total number of halogen atoms in the sulfide electrolyte, it is acceptable.

[0052] The sulfide solid electrolyte provided in this application can improve the air stability of the oxygen-doped sulfide solid electrolyte by doping it with oxygen, thereby optimizing the air stability of the sulfide solid electrolyte.

[0053] This application also provides a method for preparing a sulfide solid electrolyte, which is used to prepare the sulfide solid electrolyte as provided in the above embodiments. The preparation method includes: mixing the raw materials for preparing the sulfide solid electrolyte in a stoichiometric ratio and then sintering them to obtain the sulfide solid electrolyte.

[0054] In one specific embodiment, the preparation method includes: mixing the raw materials according to the stoichiometric ratio and then ball milling them to obtain a precursor; cold pressing the precursor into precursor particles; sintering the precursor particles, cooling them, and then ball milling them to obtain a sulfide solid electrolyte.

[0055] For example, the raw materials used in the preparation can include multiple components. One specific embodiment of the preparation method can be as follows: weighing and mixing multiple raw materials according to a stoichiometric ratio, then placing them in a ball mill for high-speed ball milling to obtain a uniformly mixed precursor, and then cold-pressing the precursor to obtain precursor particles; subjecting the precursor particles to a high-temperature sintering reaction, and then slowly cooling them to room temperature to obtain a sintered material; placing the sintered material in a ball mill for high-speed ball milling to obtain a sulfide solid electrolyte.

[0056] In one specific embodiment, the raw materials used in the preparation include LiCl, Li2S, and P2S5.

[0057] In one specific embodiment, the raw materials for preparation further include LiBr and / or Li2O.

[0058] For example, one or more of LiCl, Li2S, LiBr, and Li2O can be selected as the source of lithium in the sulfide solid electrolyte; one or more of LiCl and LiBr can be selected as the source of halogen in the sulfide solid electrolyte; P2S5 can be selected as the source of phosphorus in the sulfide solid electrolyte; P2S5 and Li2S can be selected as the source of sulfur in the sulfide solid electrolyte; and Li2O can be selected as the source of oxygen in the sulfide solid electrolyte.

[0059] It should be noted that, in the sulfide solid electrolyte provided in this application, the raw materials used as the source of lithium in the sulfide solid electrolyte can also be other compounds containing lithium, and this application does not limit this. Considering the production cost and the complexity of the preparation process of the sulfide solid electrolyte, the raw materials used as the source of lithium in the sulfide solid electrolyte provided in this application are LiCl, Li2S, LiBr, and Li2O.

[0060] It should be noted that, in the sulfide solid electrolyte provided in this application, the raw material used as the source of phosphorus in the sulfide solid electrolyte can also be other compounds containing phosphorus, and this application does not limit this. Considering the production cost and complexity of the preparation process of the sulfide solid electrolyte, in the sulfide solid electrolyte provided in this application, the raw material used as the source of phosphorus in the sulfide solid electrolyte is P2S5.

[0061] It should be noted that, in the sulfide solid electrolyte provided in this application, the raw materials used as the source of sulfur in the sulfide solid electrolyte can also be other compounds containing sulfur, and this application does not limit this. Considering the production cost and complexity of the preparation process of the sulfide solid electrolyte, the raw materials used as the source of sulfur in the sulfide solid electrolyte provided in this application are P2S5 and Li2S.

[0062] It should be noted that, in the sulfide solid electrolyte provided in this application, the raw materials used as the halogen source in the sulfide solid electrolyte can also be other compounds containing halide ions, and this application does not limit this. Considering the production cost and complexity of the preparation process of the sulfide solid electrolyte, in the sulfide solid electrolyte provided in this application, the raw materials used as the halogen source in the sulfide solid electrolyte are LiCl and LiBr.

[0063] It should be noted that, compared to the related technologies that improve the air stability and ionic conductivity of sulfide solid electrolytes by doping with zinc, oxygen and antimony, the preparation process of sulfide solid electrolytes is more complex. The preparation process of the sulfide solid electrolyte provided in this application is simpler, less complex and has lower raw material costs, which can reduce the production cost of sulfide solid electrolytes.

[0064] In one specific embodiment, when the raw materials include LiCl, Li2S and P2S5, the stoichiometric ratio of LiCl, Li2S and P2S5 when mixed is 2(1+x):(5-2x):1.

[0065] When the raw materials include LiCl, Li2S, P2S5 and LiBr, the stoichiometric ratio of LiCl, Li2S, P2S5 and LiBr when mixed is 2(1+xz):(5-2x):1:2z;

[0066] When the raw materials include LiCl, Li2S, P2S5 and Li2O, the stoichiometric ratio of LiCl, Li2S, P2S5 and Li2O is 2(1+x):(5-2x-2y):1:2y;

[0067] When the raw materials include LiCl, Li2S, P2S5, LiBr and Li2O, the stoichiometric ratio of the mixture of LiCl, Li2S, P2S5, LiBr and Li2O is 2(1+xz):(5-2x-2y):1:2z:2y; where 0.0≤x≤0.7, 0.0≤y≤0.3, and 0.0≤z≤0.7.

[0068] For example, the specific values ​​of x, y, and z are similar to those described above, and will not be repeated here.

[0069] It is understandable that when the above-mentioned different compounds are mixed, their corresponding stoichiometric ratios are determined based on the molecular formula of the prepared sulfide solid medium.

[0070] In one specific embodiment, after the precursor particles are sintered and cooled, during the ball milling process, the ball milling speed is 300 r / min-1000 r / min and the ball milling time is 25 h-50 h.

[0071] For example, the ball mill speed can be a range of 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, 550 r / min, 600 r / min, 650 r / min, 700 r / min, 750 r / min, 800 r / min, 850 r / min, 900 r / min, 950 r / min, 1000 r / min or any combination thereof.

[0072] For example, the ball milling time can be a range of 25h, 30h, 35h, 40h, 45h, 50h, or any combination thereof.

[0073] It should be noted that when the raw materials for preparing the sulfide solid electrolyte are different, the proportion of halogen atoms occupying the 4d Wyckoff position in the sulfide solid electrolyte must be 0.20-0.40% of the total number of halogen atoms in the sulfide solid electrolyte. This requires different ball milling speeds and times during the ball milling process. In the preparation of the sulfide solid electrolyte provided in the embodiments of this application, the ball milling speed is 300 r / min-1000 r / min, and the ball milling time is 25 h-50 h.

[0074] In one specific embodiment, the sintering temperature is 100℃-800℃, and the sintering time is 1h-30h.

[0075] For example, the sintering temperature of the sintering precursor particles can be a range of 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, or any combination thereof.

[0076] For example, the sintering time of the sintering precursor particles can be 1h, 5h, 10h, 15h, 20h, 25h, 30h, or any combination thereof.

[0077] It should be noted that when the raw materials for preparing the sulfide solid electrolyte are different, the proportion of halogen atoms occupying the 4d Wyckoff position in the sulfide solid electrolyte must be 0.20-0.40% of the total number of halogen atoms in the sulfide solid electrolyte. This corresponds to different sintering temperatures and times for the sintering precursor particles. In the preparation of the sulfide solid electrolyte provided in the embodiments of this application, the sintering temperature is 100℃-800℃, and the sintering time is 1h-30h.

[0078] In one specific embodiment, the preparation process of the sulfide solid electrolyte is carried out in an inert atmosphere, and the water pressure and oxygen partial pressure are both less than 0.1 ppm throughout the entire preparation process.

[0079] For example, the inert atmosphere can be an argon atmosphere or a nitrogen atmosphere.

[0080] Understandably, by ensuring that the preparation process of the sulfide solid electrolyte is carried out in an inert atmosphere, contact with moisture or oxygen in the air can be avoided, thereby preventing material degradation.

[0081] Understandably, the water pressure and oxygen partial pressure are both less than 0.1 ppm throughout the entire preparation process, ensuring that there is no water or oxygen during the entire preparation process, so as to guarantee the stability and performance of the prepared sulfide solid electrolyte.

[0082] In summary, the sulfide solid electrolyte provided in this application has the following advantages:

[0083] 1) It has high room temperature ionic conductivity. The optimized material composition and synthesis process endow it with excellent ionic conductivity at room temperature.

[0084] 2) Air stability stems from the doping of halogen elements in the material and the improvement of its preparation method, which enhances its stability in air and expands the operating window during handling and storage.

[0085] 3) The simplified process eliminates the need for complex and lengthy post-processing, making the production process more economical and efficient, suitable for large-scale industrial production, while using inexpensive and readily available raw materials to further reduce production costs.

[0086] 4) Due to its excellent conductivity and stability, this sulfide solid electrolyte is very suitable for use in high-safety, high-performance all-solid-state lithium-ion batteries and has broad application prospects in new energy storage devices. This application provides an efficient and economical way to prepare high-performance halide oxide solid electrolytes, which provides an important impetus for the development of all-solid-state battery technology.

[0087] This application also provides a solid-state battery 1, including a sulfide solid electrolyte as provided in the above embodiments, or a sulfide solid electrolyte prepared according to the preparation method provided in the above embodiments.

[0088] In one specific embodiment, the solid-state battery 1 includes a positive electrode, a negative electrode, and a solid electrolyte membrane disposed between the positive electrode and the negative electrode. At least one of the positive electrode, the negative electrode, and the solid electrolyte membrane comprises a sulfide solid electrolyte as provided in the above embodiment, or a sulfide solid electrolyte prepared by the preparation method provided in the above embodiment.

[0089] In one specific implementation, the solid-state battery 1 can be an all-solid-state battery.

[0090] This application also provides a battery assembly 2, including one or more solid-state batteries 1 as described in the above embodiments. The battery assembly 2 can be a battery pack or a battery module, etc.

[0091] As shown in Figure 1, the battery assembly 2 includes one or more solid-state batteries 1 as provided in the above embodiments.

[0092] This application also provides an electrical device 3, which includes the solid-state battery 1 provided in the above embodiments, or includes the battery assembly 2 as described above.

[0093] As shown in Figure 2, the electrical device 3 includes the battery assembly 2 as described above.

[0094] This application does not specifically limit the electronic device 3, which can be any electrical device including the battery 1. The electronic device 3 includes, but is not limited to, mobile phones, portable devices, laptops, electric bicycles, electric cars, electric toys, and energy storage devices.

[0095] The following detailed description, through specific embodiments, illustrates the sulfide solid electrolyte, its preparation method, and its applications provided in this application.

[0096] Unless otherwise specified, the reagents, materials and instruments used in the following examples are all conventional reagents, materials and instruments in the art, and can be obtained commercially. The reagents involved can also be synthesized by conventional methods in the art.

[0097] Example 1

[0098] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0, z = 0, and the molecular formula of the corresponding sulfide solid electrolyte is Li. 5.3 PS 4.3 Cl 1.7 Its preparation method includes the following steps:

[0099] Under an argon atmosphere and with both moisture and oxygen partial pressures less than 0.1 ppm, LiCl, Li₂S, and P₂S₅ were weighed and mixed in a stoichiometric ratio of 3.4:3.6:1. The mixture was then ball-milled at 650 rpm for 36 hours to obtain a precursor. The precursor was then cold-pressed into granules and sintered at 500°C for 3 hours under an argon atmosphere to obtain a sintered material. Finally, the sintered material was ball-milled at high speed to obtain a product with the molecular formula Li. 5.3 PS 4.3 Cl 1.7 sulfide solid electrolyte powder.

[0100] Example 2

[0101] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0, z = 0.5, and the molecular formula of the corresponding sulfide solid electrolyte is Li. 5.3 PS 4.3 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S are used instead. 5、 LiBr was weighed and mixed according to the corresponding stoichiometric ratio of 2.4:3.6:1:1.

[0102] Example 3

[0103] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S are used instead. 5、 LiBr and Li2O were weighed and mixed according to the corresponding stoichiometric ratio of 2.4:3.4:1:1:0.2.

[0104] Example 4

[0105] This embodiment provides a sulfide solid electrolyte, where x = 0.5, y = 0, and z = 0.5, corresponding to a sulfide solid electrolyte with the molecular formula Li. 5.5 PS 4.5 ClBr 0.5 The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S are used instead. 5、LiBr was weighed and mixed according to the corresponding stoichiometric ratio of 2:4:1:1.

[0106] Example 5

[0107] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.3, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS40 0.3 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S are used instead. 5、 LiBr and Li2O were weighed and mixed according to the corresponding stoichiometric ratio of 2.4:3:1:1:0.6.

[0108] Example 6

[0109] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.5, y = 0, z = 0.7, and the molecular formula of the corresponding sulfide solid electrolyte is Li. 5.5 PS 4.5 Cl 0.8 Br 0.7 The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S are used instead. 5、 LiBr was weighed and mixed according to the corresponding stoichiometric ratio of 1.6:4:1:1.4.

[0110] Example 7

[0111] This embodiment provides a sulfide solid electrolyte, where x = 0, y = 0, and z = 0.5. The corresponding molecular formula of the sulfide solid electrolyte is Li6PS5Cl. 0.5 Br 0.5 The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S are used instead. 5、 LiBr was weighed and mixed according to the corresponding stoichiometric ratio of 1:5:1:1.

[0112] Example 8

[0113] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 3, except that the sintering time is changed from 3 hours to 1 hour.

[0114] Example 9

[0115] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 3, except that the sintering time is changed from 3h to 15h.

[0116] Example 10

[0117] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 3, except that the sintering time is changed from 3h to 30h.

[0118] Example 11

[0119] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 3, except that the ball milling speed is changed from 650 r / min to 300 r / min.

[0120] Example 12

[0121] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 3, except that the ball milling speed is changed from 650 r / min to 800 r / min.

[0122] Example 13

[0123] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 3, except that the ball milling speed is changed from 650 r / min to 1000 r / min.

[0124] Example 14

[0125] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 3, except that the sintering time is changed from 36h to 25h.

[0126] Example 15

[0127] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.7, y = 0.1, z = 0.5, and the corresponding molecular formula of the sulfide solid electrolyte is Li. 5.3 PS 4.2 O 0.1 Cl 1.2 Br 0.5 The preparation method is basically the same as in Example 3, except that the sintering time is changed from 36h to 50h.

[0128] Comparative Example 1

[0129] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.1, y = 0, z = 0, and the molecular formula of the corresponding sulfide solid electrolyte is Li. 5.9 PS 4.9 Cl 1.1 The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S5 are weighed and mixed in the corresponding stoichiometric ratio of 2.2:4.8:1.

[0130] Comparative Example 2

[0131] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.2, y = 0, z = 0, and the molecular formula of the corresponding sulfide solid electrolyte is Li. 5.8 PS 4.8 Cl 1.2The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S5 are weighed and mixed in a stoichiometric ratio of 2.4:4.6:1.

[0132] Comparative Example 3

[0133] This embodiment provides a sulfide solid electrolyte. In this embodiment, x = 0.8, y = 0, z = 0, and the molecular formula of the corresponding sulfide solid electrolyte is Li. 5.2 PS 4.2 Cl 1.8 The preparation method is basically the same as in Example 1, except that LiCl, Li2S, and P2S5 are weighed and mixed in a stoichiometric ratio of 3.6:3.4:1.

[0134] Comparative Example 4

[0135] This embodiment provides a sulfide solid electrolyte, the preparation method of which is basically the same as that in Example 1, except that the high-temperature sintering reaction temperature is replaced with 300°C.

[0136] Comparative Example 5

[0137] This embodiment provides a sulfide solid electrolyte, the preparation method of which is basically the same as that in Example 1, except that the high-temperature sintering reaction temperature is replaced with 100°C.

[0138] Comparative Example 6

[0139] This embodiment provides a sulfide solid electrolyte, the preparation method of which is basically the same as that in Example 1, except that the high-temperature sintering reaction temperature is replaced with 800°C.

[0140] Comparative Example 7

[0141] This comparative example provides a sulfide solid electrolyte. In this comparative example, x = 0, y = 0, z = 0, and the molecular formula of the corresponding sulfide solid electrolyte is Li6PS5Cl. Its preparation method is basically the same as that in Example 1, except that LiCl, Li2S, and P2S5 are weighed and mixed in the corresponding stoichiometric ratio of 2:5:1.

[0142] Test case

[0143] For the sulfide solid electrolytes prepared in the above embodiments and comparative examples, the following test methods were used to test the proportion of the total number of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte to the total number of halogen atoms in the sulfide solid electrolyte, the ionic conductivity of the sulfide solid electrolyte, and the air stability of the sulfide solid electrolyte.

[0144] 1. Test of the proportion of halogen atoms occupying the 4d position at the Wyckoff position in the refined X-ray diffraction pattern to the total number of halogen atoms in the sulfide solid electrolyte:

[0145] Step 1: Obtain the XRD diffraction pattern of the sulfide solid electrolyte using an XRD diffractometer. The sulfide solid electrolyte material powder sample is uniformly dispersed on the surface of an optical glass plate, and the measurement parameters are adjusted to achieve an X-ray scanning depth of 10 μm.

[0146] Test method: incident angle 6°, working voltage 40kV, working current 40mA, scanning range 5°~120°, step size 0.01°.

[0147] Step 2: Fit the measured XRD diffraction pattern data using Rietveld refinement, including fine-tuning a series of parameters:

[0148] 1) Adjust the scale factor to match the overall intensity of the calculated and observed data;

[0149] 2) Adjust the background by using linear interpolation to adapt to intensity changes;

[0150] 3) Adjust the peak shape and use the pseudo-Voigt function to handle the peak broadening problem;

[0151] 4) Adjust the unit cell parameters and atomic coordinates to determine the lattice size and atomic positions;

[0152] 5) Adjust the fractional occupancy and thermal vibration parameters (Uiso) to describe stoichiometry and atomic dynamics. Based on the above fine-tuning of a series of parameters, the occupancy and content of various elements in the sample are quantitatively analyzed to obtain the proportion of the total occupancy of halogen atoms at the 4d Wyckoff position in the sulfide solid electrolyte to the total number of halogen atoms in the sulfide electrolyte.

[0153] 2. Testing the ionic conductivity of sulfide solid electrolytes

[0154] 1) Weigh 100mg of sulfide solid electrolyte powder, place it in an insulating sleeve with an inner diameter of 10mm, press it into shape under a pressure of 300MPa, and perform AC impedance spectroscopy to measure the impedance value of the electrolyte material.

[0155] 2) The pressed sheet sulfide solid electrolyte material was then subjected to sheet thickness and sheet area tests to obtain the sheet thickness and sheet area.

[0156] 3) Based on the impedance value, tablet thickness, and tablet area, the ionic conductivity of the sulfide solid electrolyte material is calculated using the formula σ = d / (R × S), where σ is the ionic conductivity (S / cm), d is the tablet thickness (cm), R is the impedance value (Ω), and S is the tablet area (cm²). 2 .

[0157] 3. Test of air stability of sulfide solid electrolytes

[0158] 1) Take 100 mg of the sulfide solid electrolyte powder provided in the above examples and comparative examples respectively, and place it in an environment with a temperature of 25±3℃ and a dew point of ≤-55℃ for 6 hours;

[0159] 2) After the settling period, the ionic conductivity was tested according to the above-described method, and the rate of decrease in ionic conductivity was calculated. The air stability of each modified sulfide solid electrolyte was comprehensively evaluated based on the rate of decrease in ionic conductivity and its cycling performance after air exposure. The rate of decrease in ionic conductivity can be calculated using the following formula:

[0160] Table 1 shows the parameters and test results of the sulfide solid electrolytes corresponding to the various embodiments and comparative examples provided in this application.

[0161] Table 1

[0162] Table 2

[0163] In Table 2, the total number of halogen atoms occupying the 4d position is used to represent the proportion of halogen atoms occupying the Wyckoff position 4d position in the crystal structure of the sulfide solid electrolyte to the total number of halogen atoms in the sulfide solid electrolyte.

[0164] The following conclusions can be drawn from Tables 1 and 2:

[0165] 1) As can be seen from the results of Examples 1 to 7 and Comparative Examples 1 to 6, the sulfide solid electrolyte provided in this application has a higher ionic conductivity and a lower rate of decrease in ionic conductivity when the proportion of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte is in the range of 0.20-0.40; and a lower ionic conductivity and / or a higher rate of decrease in ionic conductivity when the proportion of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte is less than 0.20 or greater than 0.40. Therefore, when the proportion of halogen atoms occupying the 4d Wyckoff position in the sulfide solid electrolyte provided in this application embodiment is in the range of 0.20-0.40, the corresponding sulfide solid electrolyte has high ionic conductivity and air stability, thereby optimizing the performance of the sulfide solid electrolyte.

[0166] 2) As can be seen from the results of Examples 1 to 7 and Comparative Example 7, the sulfide solid electrolyte provided in this application can effectively improve the ionic conductivity and air stability of the sulfide solid electrolyte, thereby optimizing the performance of the sulfide solid electrolyte.

[0167] 3) As can be seen from Examples 3 and 5, oxygen doping can improve the air stability of sulfide solid electrolytes;

[0168] 4) Compared with Example 1, Comparative Example 1 and Comparative Example 2 only doped with chlorine, and the amount of chlorine doping was small. As a result, the proportion of halogen atoms occupying the 4d position of the Wyckoff position in the prepared sulfide solid electrolyte was significantly smaller than that of the total number of halogen atoms in the sulfide solid electrolyte, and was less than 0.20. As a result, the ionic conductivity of the sulfide solid electrolyte was significantly reduced.

[0169] 5) Compared with Example 1, Comparative Examples 4 to 6 changed the temperature of the high-temperature sintering reaction. The proportion of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte to the total number of halogen atoms in the sulfide solid electrolyte increased when the sintering temperature increased. The ionic conductivity of the sulfide solid electrolyte increased and the rate of decrease in ionic conductivity decreased.

[0170] 6) Compared with Example 3, Examples 8 to 10 changed the sintering time. The proportion of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte to the total number of halogen atoms in the sulfide solid electrolyte increased with the extension of sintering time, and the ionic conductivity of the sulfide solid electrolyte was improved.

[0171] 7) Compared with Example 3, Examples 11 to 13 changed the ball milling speed. The proportion of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte to the total number of halogen atoms in the sulfide solid electrolyte increased with the increase of ball milling speed, and the ionic conductivity of the sulfide solid electrolyte was improved.

[0172] 8) Compared with Example 3, Examples 14 and 15 changed the ball milling time. The proportion of halogen atoms occupying the 4d position of the Wyckoff position in the sulfide solid electrolyte increased with the extension of ball milling time, and the ionic conductivity of the sulfide solid electrolyte was improved.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still 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. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A sulfide solid electrolyte, characterized in that, The sulfide solid electrolyte contains halogens, and in the crystal structure of the sulfide solid electrolyte, the number of halogen atoms occupying the 4d position of the Wyckoff position accounts for 0.20-0.40% of the total number of halogen atoms in the sulfide solid electrolyte.

2. The sulfide solid electrolyte according to claim 1, characterized in that, The sulfide solid electrolyte includes doped or undoped lithium phosphorus sulfide chloride solid electrolytes.

3. The sulfide solid electrolyte according to claim 1, characterized in that, The molecular formula of the sulfide solid electrolyte is Li 6-x PS 5-x-y O y Cl 1+x-z Br z , where 0≤x≤0.7, 0≤y≤0.3, 0≤z≤0.7, and x and z are not both zero.

4. A method for preparing a sulfide solid electrolyte, characterized in that, The method for preparing the sulfide solid electrolyte as described in any one of claims 1 to 3 comprises: The raw materials for preparing the sulfide solid electrolyte are mixed in stoichiometric ratio and then sintered to obtain the sulfide solid electrolyte.

5. The preparation method according to claim 4, characterized in that, The step of mixing the raw materials for preparing the sulfide solid electrolyte according to a stoichiometric ratio and then sintering them to obtain the sulfide solid electrolyte includes: The raw materials were mixed according to the stoichiometric ratio and then ball-milled to obtain the precursor. The precursor is cold-pressed into precursor particles; The precursor particles were sintered, cooled, and ball-milled to obtain the sulfide solid electrolyte.

6. The preparation method according to claim 4 or 5, characterized in that, The raw materials used in the preparation include LiCl, Li2S, and P2S5.

7. The preparation method according to any one of claims 4 to 6, characterized in that, The raw materials used in the preparation also include LiBr and / or Li2O.

8. The preparation method according to any one of claims 4 to 7, characterized in that, After the precursor particles are sintered and cooled, the ball milling process is carried out at a rotation speed of 300 r / min to 1000 r / min and a milling time of 25 h to 50 h.

9. The preparation method according to any one of claims 4 to 8, characterized in that, The sintering temperature is 100℃-800℃, and the sintering time is 1h-30h.

10. The preparation method according to any one of claims 4 to 9, characterized in that, The preparation process of the sulfide solid electrolyte is carried out in an inert atmosphere, and the water pressure and oxygen partial pressure are both less than 0.1 ppm throughout the entire preparation process.

11. A solid-state battery (1), characterized in that, Includes the sulfide solid electrolyte as described in any one of claims 1 to 3 or the sulfide solid electrolyte prepared by the preparation method described in any one of claims 4 to 10.

12. The solid-state battery (1) according to claim 11, characterized in that, The solid-state battery (1) includes a positive electrode, a negative electrode, and a solid electrolyte membrane disposed between the positive electrode and the negative electrode. At least one of the positive electrode, the negative electrode, and the solid electrolyte membrane comprises a sulfide solid electrolyte as described in any one of claims 1 to 3 or a sulfide solid electrolyte prepared by any one of claims 4 to 9.

13. The solid-state battery (1) according to claim 11 or 12, characterized in that, The solid-state battery (1) is an all-solid-state battery.

14. A battery assembly (2), characterized in that, Includes one or more solid-state batteries as described in any one of claims 11 to 13 (1).

15. An electrical appliance (3), characterized in that, The electrical device (3) includes a solid-state battery (1) as claimed in any one of claims 11 to 13, or the electrical device (3) includes a battery assembly (2) as claimed in claim 14.

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