Solid-state battery cell, composite electrolyte material, battery device, and electric device

Abstract

The present application relates to the technical field of batteries, and discloses a solid-state battery cell, a composite electrolyte material, a battery device, and an electric device. The solid-state battery cell comprises a solid-state electrolyte membrane, the solid-state electrolyte membrane comprises the composite electrolyte material, the composite electrolyte material comprises sulfide electrolytes and a dispersant, and the molecular structure of the dispersant contains a structural unit A and a structural unit B. The structural unit B containing an acrylate structural group can provide a steric hindrance effect, thereby reducing mutual approach and agglomeration between particles of the sulfide electrolytes. The structural unit A containing an acrylic acid structural group can provide good wettability and surface adsorptivity, enabling the dispersant to uniformly cover the surfaces of the particles of the sulfide electrolytes. Due to the action of the dispersant, the sulfide electrolytes can be uniformly dispersed in the preparation process, and a formed electrolyte membrane has uniform thickness and no obvious defects.

Description

Solid-state battery cells, composite electrolyte materials, battery devices and electrical devices

[0001] This application claims priority to Chinese Patent Application No. 202411870311.3, filed on December 18, 2024, entitled "Solid-state battery cell, composite electrolyte material, battery device and power supply device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of battery technology, specifically relating to a solid-state battery cell, a composite electrolyte material, a battery device, and an electrical device. Background Technology

[0003] Sulfide electrolytes have become a promising solid-state electrolyte due to their excellent ionic conductivity and fast lithium-ion kinetics. Currently, sulfide electrolytes are among the most mature materials used in solid-state battery electrolyte layers. Most sulfide solid-state electrolytes, after sintering and crushing, typically have particle sizes ranging from micrometers to nanometers.

[0004] However, sulfide electrolytes face several challenges during long-term storage. These materials readily absorb moisture from the air, leading to deliquescence and affecting their performance. Furthermore, due to their high specific surface energy, sulfide electrolytes are prone to particle agglomeration, forming large-diameter secondary particles. These secondary particles are difficult to disperse, making slurry preparation and dispersion in subsequent processes challenging. Particle agglomeration and poor dispersion result in uneven electrolyte membrane thickness and may lead to defects and cracks. These problems not only affect the quality of the electrolyte membrane but may also reduce the battery's cycle performance. Summary of the Invention

[0005] In view of the above problems, this application provides a solid-state battery cell, a composite electrolyte material, a battery device, and an electrical device, aiming to solve the problem of decreased battery cycle performance caused by the easy agglomeration of sulfide electrolyte particles during storage.

[0006] In a first aspect, embodiments of this application provide a solid-state battery cell, including a solid-state electrolyte membrane. The solid-state electrolyte membrane includes a composite electrolyte material, which includes a sulfide electrolyte and a dispersant. The molecular structure of the dispersant contains structural unit A and structural unit B. The structural formula of structural unit A is shown in Formula I; the structural formula of structural unit B is shown in Formula II and / or Formula III.

[0007] R1, R3, and R5 are each independently selected from hydrogen and C1-C6 alkyl groups; R2 is selected from C2-C6 alkyl groups. 20 One of the alkyl groups; R4 is selected from hydrogen, C1 to C2.20 One of the alkyl groups.

[0008] This application's embodiments, through theoretical research and experimental screening, identified a dispersant containing structural units A and B. The structural formulas of these units indicate that the dispersant is a polyacrylate dispersant. Polyacrylate dispersants themselves do not chemically react with the sulfide electrolyte, meaning they do not alter the chemical properties of the sulfide electrolyte. Structural unit B, containing acrylate structural groups, provides steric hindrance, thereby reducing the proximity and aggregation of sulfide electrolyte particles. Structural unit A, containing acrylate structural groups, provides good wettability and surface adsorption, allowing the dispersant to uniformly cover the surface of the sulfide electrolyte particles. The presence of structural unit A also makes the successful preparation of the dispersant possible. Due to the dispersant's effect, the sulfide electrolyte material can be uniformly dispersed during preparation, resulting in an electrolyte film of uniform thickness without significant defects, significantly improving the mechanical strength of the electrolyte film while maintaining good ionic conductivity. Batteries prepared using this improved sulfide solid electrolyte film exhibit significantly improved cycle stability. This is because the improved uniformity and mechanical strength of the electrolyte film make the battery more stable during charge and discharge, extending its lifespan.

[0009] In some embodiments, the molecular structure of the dispersant is shown in Formula IV:

[0010] Wherein, 10≤n≤100, 20≤m≤400, and 20≤f≤400. When the molecular structure of the dispersant simultaneously contains structural unit B as shown in Formula II and Formula III, the anti-agglomeration effect of the dispersant is further enhanced.

[0011] In some embodiments, R1, R3, and R5 are each independently selected from hydrogen or methyl; R2 is selected from one of C4-C6 alkyl groups; R4 is selected from C... 14 ~C 16 One of the alkyl groups. This can further enhance the dispersant's effect in preventing the agglomeration of sulfide electrolyte particles.

[0012] In some embodiments, the molar ratio of structural unit A to structural unit B is 1:9 to 2:8. Controlling the molar ratio within the above range allows the dispersant to have sufficient steric hindrance to prevent the agglomeration of sulfide electrolyte particles, while avoiding the impact of excessive structural unit A on the stability of the electrolyte material, thereby further improving the overall effect of the dispersant.

[0013] In some embodiments, the ratio of n, m, to f ranges from 1:(2-4):(2-4). This can further improve the anti-agglomeration effect of the dispersant.

[0014] In some embodiments, the number-average molecular weight Mn of the dispersant is 10,000 g / mol to 60,000 g / mol. Thus, controlling the number-average molecular weight of the dispersant within an appropriate range allows it to better resist agglomeration while also being uniformly dispersed on the surface of sulfide electrolyte particles, thereby further optimizing the overall effect of the dispersant.

[0015] In some embodiments, the dispersant accounts for 0.1% to 1.5% of the total weight of the composite electrolyte material. Compared to other dispersants, the dispersant used in this application is used in a smaller amount in the composite electrolyte material, which can reduce non-electrolyte components in the solid electrolyte membrane, thereby improving the ionic conductivity and mechanical strength of the solid electrolyte membrane and enhancing the overall performance of the battery.

[0016] In some embodiments, the sulfide electrolyte includes Li 7-a PS5X a Li 10 MP2S 12 Li3PS4, Li7P3S 11 Li7P2S8Cl2, Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 At least one of the following: where 0 ≤ a ≤ 1.5, X is at least one of F, Cl, Br, and I, and M is at least one of Ge, Si, and Sn. Thus, solid-state batteries prepared by combining the dispersant with the aforementioned sulfide electrolyte material exhibit further improved performance.

[0017] In some embodiments, the D of the electrolyte material V 50 Particle size ≤ 2μm, D V 90. Particle size < 5 μm. Due to the addition of dispersant, the electrolyte material of this application embodiment was tested again for particle size distribution after 90 days of storage, and the obtained sample still met the D... V 50≤2μm,D V 90 < 5 μm.

[0018] In some embodiments, the thickness of the solid electrolyte membrane is 30 μm to 100 μm. Controlling the thickness of the solid electrolyte membrane within this range allows for a better balance between the membrane's mechanical strength and low internal resistance, thereby achieving better performance and reliability in practical applications.

[0019] Secondly, embodiments of this application provide a composite electrolyte material, comprising a sulfide electrolyte and a dispersant, wherein the molecular structure of the dispersant contains structural unit A and structural unit B, wherein the structural formula of structural unit A is shown in Formula I; and the structural formula of structural unit B is shown in Formula II and / or Formula III.

[0020] R1, R3, and R5 are each independently selected from hydrogen and C1-C6 alkyl groups; R2 is selected from C2-C6 alkyl groups. 20 Alkyl group; R4 is selected from hydrogen, C1 to C2. 20 alkyl.

[0021] In some embodiments, the molecular structure of the dispersant is shown in Formula IV:

[0022] Where 10≤n≤100, 20≤m≤400, and 20≤f≤400.

[0023] In some embodiments, R1, R3, and R5 are each independently selected from hydrogen or methyl; R2 is selected from one of C4-C6 alkyl groups; R4 is selected from C... 14 ~C 16 One of the alkyl groups.

[0024] In some embodiments, the molar ratio of structural unit A to structural unit B is 1:9 to 2:8.

[0025] In some embodiments, the ratio of n, m and f ranges from 1:(2 to 4):(2 to 4).

[0026] In some embodiments, the composite electrolyte material satisfies at least one of (1) to (4):

[0027] (1) The number average molecular weight Mn of the dispersant is 10000 g / mol to 60000 g / mol;

[0028] (2) The weight of the dispersant accounts for 0.1% to 1.5% of the total weight of the composite electrolyte material;

[0029] (3) The sulfide electrolyte includes Li 7-a PS5X a Li 10 MP2S 12 Li3PS4, Li7P3S 11 Li7P2S8Cl2, Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S11.7 Cl 0.3 At least one of the following: where 0 ≤ a ≤ 1.5, X is at least one of F, Cl, Br, I, and M is at least one of Ge, Si, Sn;

[0030] (4) D of the composite electrolyte material V 50 Particle size ≤ 2μm, D V 90 Particle size < 5 μm.

[0031] Thirdly, embodiments of this application provide a method for preparing a composite electrolyte material, comprising the following steps: mixing a sulfide electrolyte, a dispersant, and a solvent, followed by heat treatment to obtain the composite electrolyte material; wherein the molecular structure of the dispersant contains structural unit A and structural unit B, the structural formula of structural unit A being shown in Formula I; and the structural formula of structural unit B being shown in Formula II and / or Formula III.

[0032] R1, R3, and R5 are each independently selected from hydrogen and C1 to C6 alkyl groups;

[0033] R2 is selected from C2~C 20 alkyl;

[0034] R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups.

[0035] This application successfully suppressed the agglomeration of sulfide electrolyte particles during long-term storage by introducing a dispersant containing structural units A and B during the grinding process of the sulfide electrolyte material, thus preventing the formation of large secondary particles. This characteristic not only eliminates the need for additional dispersants during the wet preparation of solid electrolyte membranes but also continues to function under dry storage conditions, significantly improving the stability and uniformity of the material.

[0036] Specifically, the selected dispersant not only exhibits excellent dispersion performance in the wet preparation stage of sulfide electrolytes, but also maintains its ability to inhibit agglomeration under dry storage conditions for a long period of time. This means that throughout the entire preparation and storage process, from the initial raw material mixing to the final product storage, the dispersant can continuously play a role, ensuring that the sulfide electrolyte particles always maintain a good dispersion state.

[0037] In this way, the stability and uniformity of the sulfide electrolyte are significantly improved at each stage, thereby enhancing the quality of the final solid electrolyte membrane. This stable dispersion not only helps improve the microstructure of the material but also further improves the overall performance of the battery, including ionic conductivity, mechanical strength, and cycle stability.

[0038] In some embodiments, the solvent includes at least one selected from trimethylbenzene, xylene, toluene, n-heptane, n-decane, n-octane, n-nonane, butyl butyrate, and pentyl valerate. These solvents are all weakly polar or non-polar solvents with moderate viscosity, making them more suitable for the uniform dispersion of the sulfide electrolyte materials and dispersants in the embodiments of this application.

[0039] In some embodiments, the solvent comprises thiol and butyl butyrate, wherein the volume ratio of thiol to butyl butyrate is 3:7 to 7:3; or the solvent comprises n-heptane and butyl butyrate, wherein the volume ratio of n-heptane to butyl butyrate is 3:7 to 7:3. Using a combination of thiol and butyl butyrate, or a combination of n-heptane and butyl butyrate, as the solvent provides better dispersion.

[0040] In some embodiments, the mixing process includes grinding the sulfide electrolyte, the dispersant, and the solvent, wherein the grinding conditions include a ball milling speed of 400 rpm to 600 rpm and a ball milling time of 5 h to 10 h.

[0041] In some embodiments, the heat treatment includes heating at 80°C to 120°C for 4 to 12 hours under an inert atmosphere.

[0042] In some embodiments, the dispersant is formed by polymerizing monomers in the presence of an initiator; the polymerizing monomers include a first monomer and a second monomer, the first monomer having the structural formula shown in formula (a), and the second monomer having the structural formula shown in formula (b) and / or formula (c):

[0043] R1, R3, and R5 are each independently selected from hydrogen and C1-C6 alkyl groups; R2 is selected from C2-C6 alkyl groups. 20 Alkyl group; R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups.

[0044] Thirdly, embodiments of this application provide a battery device including the solid-state battery cell described in the first aspect. Thus, because the solid-state battery cell has good cycle performance, the battery device has even better performance.

[0045] Fourthly, embodiments of this application provide an electrical device including a solid-state battery cell as described in the first aspect, or a battery device as described in the third aspect, wherein the solid-state battery cell or the battery device is used to store or provide electrical energy. Thus, the performance of the electrical device is improved.

[0046] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0047] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0048] Figure 1 is a schematic diagram of the structure of an electrical device (vehicle) provided in some embodiments of this application;

[0049] Figure 2 is an exploded structural diagram of a battery device provided in some embodiments of this application;

[0050] Figure 3 is a schematic diagram of the structure of a solid-state battery cell according to some embodiments of this application;

[0051] Figure 4 shows the particle size distribution curves of the electrolyte materials of Example 1 and Comparative Example 1 of this application at the time of preparation and after 90 days of storage.

[0052] The reference numerals in the detailed embodiments are as follows:

[0053] 1-Vehicle; 2-Battery unit; 3-Controller; 4-Motor;

[0054] 5-Box body; 51-First box body section; 52-Second box body section; 53-Accommodation space;

[0055] 7-Solid-state battery cell; 11-Main body; 12-Alt tab. Detailed Implementation

[0056] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0057] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0058] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0059] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0060] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0061] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0062] Sulfide electrolytes are electrolyte materials used in solid-state batteries, typically exhibiting high ionic conductivity and good chemical stability. However, sulfide electrolytes are susceptible to various microscopic effects during storage, such as water absorption and electrostatic forces, which can lead to particle agglomeration. Agglomerated particles are more prone to further aggregation during storage, resulting in decreased electrolyte stability. Agglomeration also increases the average particle size, making it difficult to uniformly disperse large electrolyte particles during slurry preparation and coating. This can lead to uneven thickness and defects in the solid-state electrolyte film, ultimately affecting the performance of the solid-state battery.

[0063] Based on this, embodiments of this application propose a composite electrolyte material, comprising a sulfide electrolyte and a dispersant. The molecular structure of the dispersant contains structural unit A and structural unit B. The structural formula of structural unit A is shown in Formula I; the structural formula of structural unit B is shown in Formula II and / or Formula III.

[0064] R1, R3, and R5 are each independently selected from hydrogen and C1-C6 alkyl groups;

[0065] R2 is selected from C2~C 20 alkyl;

[0066] R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups. When R4 is selected from C1 to C2. 20 When R4 is an alkyl group, it is an alkane group that substituted for any hydrogen atom on the benzene ring and has 1 to 20 carbon atoms.

[0067] The term "C1-C6 alkyl" refers to a straight-chain or branched saturated hydrocarbon group containing 1 to 6 carbon atoms. For example, C1-C6 alkyl includes, but is not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-2-butyl, 3-methyl-2-butyl, 3-methyl-1-butyl, 2-methyl-1-butyl, n-hexyl, 2-hexyl, 3-hexyl, etc.

[0068] The term "C2~C" 20 "Alkyl" refers to a straight-chain or branched saturated hydrocarbon group containing 2 to 20 carbon atoms.

[0069] The term "C1~C" 20 "Alkyl" refers to a straight-chain or branched saturated hydrocarbon group containing 1 to 20 carbon atoms.

[0070] Specifically, the structural formula of the dispersant may include structural unit A and structural unit B as shown in Formula II, or may include structural unit A and structural unit B as shown in Formula III, or may include structural unit A, structural unit B as shown in Formula II and structural unit B as shown in Formula III.

[0071] The structural units in a dispersant can be detected using infrared spectroscopy. By analyzing the wavelength, intensity, and shape of the infrared absorption bands, specific functional groups and chemical bonds within the structural units can be identified, thus inferring their structural composition. The structural formula of structural unit A shows that it includes acrylic acid structural groups, and the structural formula of structural unit B shows that it includes acrylate structural groups. This indicates that the dispersant is a polyacrylate dispersant. Polyacrylate dispersants possess a polymeric network block structure, which spatially prevents sulfide electrolyte particles from absorbing water, thereby preventing aggregation due to water absorption. Because it includes structural unit A, this polyacrylate dispersant exhibits good wettability and can uniformly cover the surface of the sulfide electrolyte particles. Because it includes structural unit B, the steric hindrance effect of the acrylate structural groups reduces the mutual attraction between particles, thus preventing aggregation of sulfide electrolyte particles during preparation and storage.

[0072] In some embodiments, the molecular structure of the dispersant is shown in Formula IV:

[0073] Where 10≤n≤100, 20≤m≤400, and 20≤f≤400.

[0074] In some embodiments, R1, R3, and R5 are each independently selected from hydrogen or methyl; R2 is selected from one of C4-C6 alkyl groups; R4 is selected from C... 14 ~C 16 One of the alkyl groups.

[0075] Thus, structural unit A can be at least one of the following formulas (1) to (2):

[0076] The structural formula of structural unit B can be at least one of the following formulas (3) to (14):

[0077] In some embodiments, the molar ratio of structural unit A to structural unit B is 1:9 to 2:8. As examples, typical but non-limiting values ​​include 1:9, 1.2:8.8, 1.4:8.6, 1.6:8.4, 1.8:8.2, and 2:8. Because structural unit A has shorter chain segments while structural unit B has long-chain functional groups, if the proportion of short-chain structural unit A is too high, the proportion of structural unit B containing long-chain functional groups will decrease, resulting in shorter branches of each functional group in the polyacrylate copolymer. The steric hindrance effect of the short-chain dispersant is weakened. Therefore, its ability to prevent the aggregation of sulfide electrolyte particles is reduced. Simultaneously, because structural unit A contains -COOH, it has a certain degree of acidity; if its content is too high, the dispersant is prone to react with the sulfide electrolyte, affecting the stability of the electrolyte material. However, if the proportion of structural unit A is too low, the synthesis and preparation of the polyacrylate copolymer will become difficult. Therefore, controlling the molar ratio of the two within the above range can further improve the anti-agglomeration effect of the dispersant on the sulfide electrolyte.

[0078] In some embodiments, the ratio of n, m, and f ranges from 1:(2 to 4):(2 to 4). As an example, n:m:f can be typical but not limiting values ​​such as 1:2:2, 1:2:3, 1:2:4, 1:3:2, 1:3:3, 1:3:4, 1:4:2, 1:4:3, 1:4:4, etc.

[0079] In some embodiments, the number-average molecular weight (Mn) of the dispersant is between 10,000 g / mol and 60,000 g / mol. As examples, the number-average molecular weight (Mn) of the dispersant can be typical but not limiting values ​​such as 10,000 g / mol, 20,000 g / mol, 30,000 g / mol, 40,000 g / mol, 50,000 g / mol, and 60,000 g / mol. Number-average molecular weight (Mn) is a statistical average of the molecular weight of a polymer, used to describe the average molecular weight in a polymer sample. If the number-average molecular weight of the dispersant is too low, the anti-agglomeration effect is weakened; if the number-average molecular weight is too high, its uniform dispersion effect will decrease. This is because if the molecular weight of a single molecule is large, it becomes more difficult for it to form a uniform protective layer on the surface of the sulfide electrolyte particles, thus affecting the anti-agglomeration effect. Therefore, controlling the number-average molecular weight of the dispersant within the above range can better achieve uniform dispersion and anti-agglomeration effects.

[0080] In some embodiments, the weight of the dispersant accounts for 0.1% to 1.5% of the total weight of the composite electrolyte material. As examples, the weight percentage of the dispersant can be typical but not limiting values ​​such as 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, and 1.5%. Compared to other dispersants, the dispersant used in the embodiments of this application is less. When the amount of dispersant is less, the proportion of sulfide electrolyte material in the solid electrolyte membrane is higher, which helps to enhance the purity of the membrane, thereby improving the ionic conductivity, mechanical strength, and toughness of the solid electrolyte membrane.

[0081] In this application embodiment, there is no particular limitation on the type of sulfide electrolyte, and all known sulfide materials used in the battery field are acceptable. Sulfide solid electrolytes can be classified into three types based on their structural characteristics: crystalline, glassy, ​​and glass-ceramic. Crystalline sulfide electrolytes typically possess high ionic conductivity and mechanical strength; glassy sulfide electrolytes exhibit good mechanical flexibility and processability; and glass-ceramic sulfide electrolytes combine the advantages of both. As an example, crystalline sulfide electrolytes include: Thio-LISICON (a thiolated lithium-ion superconductor such as Li7P3S). 11 etc.), LGPS series (such as Li 10 GeP2S 12Examples of glassy sulfide electrolytes include: Li₂S-P₂S₅ system (a complex of Li₂S and P₂S₅), LiI-Li₂S-P₂S₅ (a complex of LiI, Li₂S, and P₂S₅), and Li₂S-SiS₂ (a complex of Li₂S and SiS₂). Examples of glassy ceramic sulfide electrolytes include: Li₂S-P₂S₅ (a complex of Li₂S and P₂S₅), LiI-Li₂S-P₂S₅ (a complex of LiI, Li₂S, and P₂S₅), and Li₂S-SiS₂ (a complex of Li₂S and SiS₂).

[0082] In some alternative embodiments, the sulfide electrolyte includes Li 7-a PS5X a Li 10 MP2S 12 Li3PS4, Li7P3S 11 Li7P2S8Cl2, Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 At least one of the following; wherein 0 ≤ a ≤ 1.5, X is at least one of F, Cl, Br, I, and M is at least one of Ge, Si, Sn. As examples, sulfide electrolytes include Li6PS5Cl, Li... 6.5 PS5Br 0.5 Li 6.5 PS5i 0.5 Li 5.75 PS5Cl 1.25 Li 6.5 PS5Cl 0.5 Li 6.75 PS5Br 0.25 Li 10 GeP2S 12 Li 10 SiP2S 12 Li 10 SnP2S 12 Li3PS4, Li7P3S 11 Li7P2S8Cl2, Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl0.3 wait.

[0083] In some embodiments, the D of the composite electrolyte material V 50 Particle size ≤ 2μm, D V 90. Particle size < 5 μm. (D) V 50 particle size and D V Particle size and particle size are two commonly used parameters in particle size distribution, used to describe the particle size distribution characteristics of powder or granular materials. They represent the cumulative percentage of particles smaller than their respective diameters. V 50% particle size refers to the particle size that corresponds to 50% of the cumulative volume or mass in a sample. V The median particle size (50) is the median of the particle size distribution and is often used to represent the average particle size of powders. It is an important indicator for measuring the central tendency of powder particle size distribution. V 90% particle size refers to the particle size that accounts for 90% of the total volume or mass of a sample. (D) V The particle size index (PMI) reflects the size of the larger particles in a powder and is commonly used to assess the proportion of coarse particles in a powder. It can help determine whether a powder contains a large number of large particles, thus affecting its flowability and dispersibility.

[0084] This application also provides a method for preparing a composite electrolyte material, comprising the following steps: mixing a sulfide electrolyte, a dispersant, and a solvent, followed by heat treatment to obtain the composite electrolyte material. The dispersant has a molecular structure containing structural unit A and structural unit B. The structural formula of structural unit A is shown in Formula I; the structural formula of structural unit B is shown in Formula II and / or Formula III.

[0085] R1, R3, and R5 are each independently selected from hydrogen and C1-C6 alkyl groups; R2 is selected from C2-C6 alkyl groups. 20 Alkyl group; R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups.

[0086] The step "mixing treatment" can be specifically as follows: place the (preliminarily ground and crushed) sulfide electrolyte in a ball mill, then add solvent and dispersant, then add grinding media (such as zirconium beads), and then perform ball milling at a certain speed. After ball milling, remove the grinding media (such as zirconium beads).

[0087] In some embodiments, the solvent includes at least one selected from trimethylbenzene, xylene, toluene, n-heptane, n-decane, n-octane, n-nonane, butyl butyrate, and pentyl valerate. Trimethylbenzene, xylene, and toluene, these aromatic hydrocarbon solvents, have moderate boiling points and low viscosity, providing sufficient solubility and volatility while maintaining good dispersibility. They are weakly polar, suitable for hydrophobic sulfide electrolytes, and do not chemically react with the electrolyte. n-Heptane, n-decane, n-octane, and n-nonane, these straight-chain alkane solvents, have very low polarity and viscosity, better preventing the agglomeration of sulfide electrolyte particles, and due to their low polarity, they hardly chemically react with the electrolyte. Furthermore, their moderate volatility allows for rapid evaporation after coating, leaving a uniform electrode layer. Butyl butyrate and pentyl valerate are weakly polar solvents, providing good dispersibility and stability. They have low viscosity and moderate volatility, acting as good plasticizers in the slurry without significantly increasing its viscosity. In addition, ester solvents have a higher boiling point, which can regulate the drying speed of the slurry to a certain extent and avoid cracks or unevenness caused by excessively fast drying.

[0088] In some embodiments, the solvent comprises thiol and butyl butyrate, wherein the volume ratio of thiol to butyl butyrate is 3:7 to 7:3, for example, typical but non-limiting values ​​such as 3:7, 4:6, 5:5, 6:4, 7:3, etc.

[0089] In some embodiments, the solvent comprises n-heptane and butyl butyrate, wherein the volume ratio of n-heptane to butyl butyrate is 3:7 to 7:3, for example, typical but non-limiting values ​​such as 3:7, 4:6, 5:5, 6:4, 7:3, etc.

[0090] In some embodiments, the mixing process includes grinding the sulfide electrolyte, dispersant, and solvent under the following conditions: a ball-to-material ratio of (2–6):1, a ball milling speed of 400–600 rpm, and a ball milling time of 5–10 h. The "ball-to-material ratio" refers to the ratio of the weight of the grinding media to the weight of the material in a ball mill. Here, the grinding media includes zirconium beads, and the material includes the sulfide electrolyte, dispersant, and solvent.

[0091] The step "Heat treatment to obtain composite electrolyte material" can be specifically as follows: the mixed material is transferred to a heating device for heat treatment under an inert atmosphere, and then naturally cooled after heat treatment to obtain the composite electrolyte material containing the dispersant. The heating device can be selected according to process requirements and production scale, such as a tube furnace, box furnace, or rotary furnace.

[0092] In some embodiments, the heat treatment includes heating at 80°C to 120°C for 4 to 12 hours under an inert atmosphere. The inert atmosphere includes at least one of nitrogen, argon, and helium.

[0093] In some embodiments, the dispersant is formed by polymerization of a polymeric monomer in the presence of an initiator; the polymeric monomer includes a first monomer and a second monomer, the first monomer having the structural formula shown in formula (a), and the second monomer having the structural formula shown in formula (b) and / or formula (c):

[0094] R1, R3, and R5 are each independently selected from hydrogen and C1-C6 alkyl groups; R2 is selected from C2-C6 alkyl groups. 20 Alkyl group; R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups.

[0095] As examples, the first monomer can include acrylic acid, methacrylic acid, ethyl acrylic acid, propyl acrylic acid, butyl acrylic acid, etc.; the second monomer can include butyl acrylate, ethyl acrylate, isobutyl methacrylate, isopropyl methacrylate, isopropyl acrylate, phenyl acrylate, p-toluene acrylate, etc.

[0096] Specific preparation methods can include free radical solution polymerization, i.e., polymerization of monomers in a solvent, with initiators such as azobisisobutyronitrile (AIBN) and benzoyl peroxide (BPO). Solvents can include toluene, xylene, and ethyl acetate. The polymerization temperature can be between 60℃ and 80℃. Alternatively, emulsion polymerization, i.e., free radical polymerization in an aqueous phase, can be used. Specific preparation methods can utilize known polyacrylate preparation methods in the art. The specific selection of the production process can be adjusted according to the required molecular weight and other performance requirements; this application does not impose specific limitations.

[0097] The preparation method of this application embodiment adds a dispersant during the grinding process, which makes the sulfide electrolyte less prone to agglomeration during long-term storage. In the subsequent process of preparing solid electrolyte membranes by slurry preparation, no additional dispersant needs to be added, which simplifies the process.

[0098] This application also provides a solid-state battery cell, including a solid electrolyte membrane, which comprises the aforementioned composite electrolyte material. The composite electrolyte material includes a sulfide electrolyte and a dispersant. The dispersant has a molecular structure containing structural unit A and structural unit B. The structural formula of structural unit A is shown in Formula I; the structural formula of structural unit B is shown in Formula II and / or Formula III.

[0099] R1, R3, and R5 are each independently selected from hydrogen and C1-C6 alkyl groups; R2 is selected from C2-C6 alkyl groups. 20 One of the alkyl groups; R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups.

[0100] The solid electrolyte membrane prepared using the above-mentioned composite electrolyte material has uniform thickness and no defects, and has good strength and ionic conductivity, and can be used as the electrolyte layer of solid-state batteries.

[0101] In some embodiments, the molecular structure of the dispersant is shown in Formula IV:

[0102] Wherein, 10≤n≤100, 20≤m≤400, and 20≤f≤400. When the molecular structure of the dispersant simultaneously contains structural unit B as shown in Formula II and Formula III, the anti-agglomeration effect of the dispersant is further enhanced.

[0103] In some embodiments, R1, R3, and R5 are each independently selected from hydrogen or methyl; R2 is selected from one of C4-C6 alkyl groups; R4 is selected from C... 14 ~C 16 One of the alkyl groups.

[0104] In some embodiments, the molar ratio of structural unit A to structural unit B is 1:9 to 2:8.

[0105] In some embodiments, the ratio of n, m and f ranges from 1:(2 to 4):(2 to 4).

[0106] In some embodiments, the number-average molecular weight Mn of the dispersant is 10000 g / mol to 60000 g / mol.

[0107] In some embodiments, the weight of the dispersant accounts for 0.1% to 1.5% of the total weight of the composite electrolyte material.

[0108] In some embodiments, the sulfide electrolyte includes Li 7-a PS5X a Li 10 MP2S 12 Li3PS4, Li7P3S 11 Li7P2S8Cl2, Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 At least one of the following: where 0 ≤ a ≤ 1.5, X is at least one of F, Cl, Br, I, and M is at least one of Ge, Si, Sn.

[0109] In some embodiments, the D of the electrolyte material V 50 Particle size ≤ 2μm, D V 90 Particle size < 5 μm.

[0110] After preparing the above-mentioned composite electrolyte material, it can be made into a slurry, and then the slurry can be coated or cast into a solid electrolyte membrane. The step of "making the slurry" specifically includes: adding the composite electrolyte material to a stirring container containing a second solvent and stirring; adding a binder; and continuing to stir to make the slurry. The second solvent includes, but is not limited to, one or more combinations of mesitylene, pseudo-trimethylbenzene, m-xylene, p-xylene, toluene, n-heptane, n-decane, n-octane, n-nonane, butyl butyrate, and pentyl valerate. The binder includes, but is not limited to, one or more combinations of NBR (acrylonitrile-butadiene copolymer), HNBR (hydrogenated acrylonitrile-butadiene copolymer), PAA (polyacrylic acid), SBS (styrene-butadiene-styrene block copolymer), PTFE (polytetrafluoroethylene), and PVDF (polyvinylidene fluoride).

[0111] The step "preparing a solid electrolyte membrane by coating or casting" specifically involves: coating the slurry onto a substrate, drying it, isothermal pressing it, and then peeling it off from the substrate to obtain the solid electrolyte membrane. The substrate may include, but is not limited to, PET (polyethylene terephthalate), PI (polyimide), PTFE (polytetrafluoroethylene), aluminum foil, etc. Isothermal pressing is a material forming process that applies uniform static pressure to powder or granular materials at a constant temperature. The isothermal pressing process conditions can be any known isothermal pressing process conditions used in the battery field. For example, the pressure in the isothermal pressing process can be 200MPa to 400MPa, the temperature can be 50℃ to 120℃, and the time can be 5s to 30s. The casting method specifically involves: starting the casting machine, allowing the substrate to pass under the slurry, using a doctor blade or similar tool to uniformly coat the slurry onto the substrate surface, and then preparing the solid electrolyte membrane through steps such as drying and heat treatment. The casting process conditions can also be any known isothermal pressing process conditions used in the battery field.

[0112] The thickness of the solid electrolyte membrane can be selected differently depending on the properties of the desired solid-state battery cell. Specifically, in some embodiments, the thickness of the solid electrolyte membrane can be from 0.1 μm to 1000 μm; in other embodiments, the thickness of the solid electrolyte membrane can be from 1 μm to 500 μm; in still other embodiments, the thickness of the solid electrolyte membrane can be from 20 μm to 30 μm; this application does not limit it in this regard.

[0113] In some alternative embodiments, the thickness of the solid electrolyte membrane is 30 μm to 100 μm, such as typical but non-limiting values ​​like 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm. Choosing this thickness range takes into account not only the balance between the membrane's mechanical strength and internal resistance, but also the type of dispersant and the characteristics of the sulfide electrolyte selected in some embodiments of this application, thereby enabling the solid electrolyte membrane to exhibit superior performance and higher reliability in practical use.

[0114] The solid-state battery cell of this application will be described in detail below.

[0115] Typically, a solid-state battery consists of a positive electrode, a negative electrode, and a solid electrolyte. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and extracting. The electrolyte acts as a conductor of ions between the positive and negative electrodes; specifically, the solid electrolyte is a solid electrolyte membrane as described above.

[0116]

Positive Electrode

[0117] The positive electrode includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector, the positive active material layer including the positive active material of the first aspect of this application. As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0118] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0119] In some embodiments, the positive electrode active material may be a known positive electrode active material for batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, and LiNi... 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0120] In some embodiments, the positive electrode active material layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0121] In some embodiments, the positive electrode active material layer may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0122] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0123] [Negative electrode plate]

[0124] The negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, the negative active material layer comprising a negative active material. As an example, the negative current collector has two surfaces opposite each other in its own thickness direction, and the negative active material layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0125] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0126] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: lithium metal, lithium-containing alloys, lithium-containing composites, artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0127] In some embodiments, the negative electrode active material includes one or more of lithium metal, lithium-containing alloys, and lithium-containing composites.

[0128] In some embodiments, the negative electrode active material layer may optionally include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0129] In some embodiments, the negative electrode active material layer may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0130] In some embodiments, the negative electrode active material layer may also optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0131] In some embodiments, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0132] In some embodiments, the positive electrode, negative electrode, and solid electrolyte membrane can be fabricated into an electrode assembly using a winding process or a stacking process.

[0133] In some embodiments, the solid-state battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.

[0134] This application also provides a battery device including the above-described solid-state battery cell. By using the above-described solid-state battery cell, the performance of the battery device is improved.

[0135] The battery device of this application will now be described in detail.

[0136] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0137] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0138] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0139] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0140] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0141] In this embodiment of the application, the battery cell can be a secondary battery cell, which refers to a battery cell that can be used again after being discharged by recharging to activate the active materials.

[0142] Battery cells may include, but are not limited to, solid-state batteries, lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-metal hydride battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0143] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0144] This application also provides an electrical device, including the aforementioned solid-state battery cell or battery device, wherein the solid-state battery cell or battery device is used to store or provide electrical energy. Thus, the performance of the electrical device is improved.

[0145] The battery device disclosed in this application can be used in electrical devices that use the battery device as a power source or in various energy storage systems that use the battery device as an energy storage element. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0146] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0147] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0148] As shown in Figure 1, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0149] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0150] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0151] Figure 2 is an exploded view of the battery device provided in some embodiments of this application.

[0152] The housing 5 is used to house the battery cells 7, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 51 and a second housing portion 52, which cover each other, and together define a housing space 53 for housing the battery cells. In the battery device 2, there may be one or more battery cells 7. If there are multiple battery cells 7, they may be connected in series, in parallel, or in a mixed manner. A mixed manner means that some of the multiple battery cells 7 are connected in series and others in parallel. Multiple battery cells 7 may be directly connected in series, in parallel, or in a mixed manner, and then the whole assembly of the multiple battery cells 7 may be housed in the housing 5; of course, multiple battery cells may also be first connected in series, in parallel, or in a mixed manner to form a battery module, and then the multiple battery modules may be connected in series, in parallel, or in a mixed manner to form a whole assembly, which may be housed in the housing 5.

[0153] In some alternative embodiments, the battery cell 7 can also be directly housed within the housing 5 to reduce the number of connecting or supporting components required to assemble the battery module and improve the energy density of the battery device 2.

[0154] For example, the battery cell 7 may be the smallest unit that makes up the battery device 2.

[0155] The battery cell 7 is a solid-state battery cell. A solid-state battery typically includes a casing 20 and an electrode assembly 10. The casing has an inner cavity, and the electrode assembly is disposed in the inner cavity. The electrode assembly includes a positive electrode, a solid electrolyte, and a negative electrode stacked together.

[0156] Please refer to Figure 3, which is a schematic diagram of the structure of a solid-state battery cell according to some embodiments of this application.

[0157] A solid-state battery cell includes a positive electrode, a negative electrode, and a solid electrolyte. The solid electrolyte is located between the positive and negative electrodes, forming an ion channel between them to allow for the transfer and reaction of positive and negative ions. Figure 3 shows the structure of a solid-state battery cell formed by stacking the positive electrode, negative electrode, and solid electrolyte. The portions of the positive and negative electrodes containing active material constitute the main body 11 of the solid-state battery, while the portions without active material constitute tabs 12. Tabs 12 can be located together at one end of the main body 11 or at both ends of the main body 11. The solid-state battery cell can be rectangular, cylindrical, or other shapes.

[0158] The following description is based on specific embodiments.

[0159] Example 1

[0160] A composite electrolyte material comprising Li6PS5Cl and a dispersant, the dispersant having the following structural formula and a number-average molecular weight of 19575 g / mol.

[0161] (1) Preparation of composite electrolyte materials

[0162] 100g of sulfide electrolyte Li6PS5Cl was initially ground and crushed, then placed in a ball mill. 400g of solvent (butyl butyrate and n-heptane, volume ratio 1:1) was added, followed by 1.5g of dispersant and 1.5kg of zirconium beads. The mixture was ball-milled at 500rpm for 8 hours. The zirconium beads were then sieved out. The material was transferred to a tube furnace and calcined at 100℃ for 8 hours under an inert atmosphere at a heating rate of 3℃ / min. After holding at this temperature, the material was allowed to cool naturally to obtain the composite electrolyte material containing the dispersant.

[0163] The preparation method of the above dispersant includes the following steps: 8.61g of the first monomer of formula (a1), 31g of the second monomer of formula (b1), 69.1g of the second monomer of formula (c1) and 50g of ethanol are mixed, 0.55g of azobisisobutyronitrile is added, and the mixture is reacted at 70°C for 12h to obtain the above dispersant.

[0164] (2) Preparation of solid electrolyte membranes

[0165] Add 2 kg of electrolyte material to a 5 L mixing tank containing 4 L of solvent. After stirring for 4 hours, add 200 g of binder and stir for 8 hours. Then coat the mixture onto a PET base film. After drying, press it into shape under 300 MPa and 100 °C for 20 seconds. Then press it into a disc with a diameter of 10 mm. Finally, peel off the substrate to obtain a solid electrolyte membrane.

[0166] (3) Assembly of solid-state battery cells

[0167] Conductive carbon, Li6PS5Cl, and NCM811 (nickel-cobalt-manganese ternary cathode material, with the specific chemical formula LiNi) are used. 0.8 Co 0.1 Mn 0.1 O2) was mixed in a mass ratio of 1:15:40 and then ground for 20 minutes to serve as the positive electrode active material.

[0168] A solid electrolyte membrane (SEM) wafer is placed in a mold. On one side of the SEM wafer, an indium sheet and a composite copper-lithium sheet are placed sequentially (with the lithium side of the composite copper-lithium sheet facing the indium sheet). The indium sheet provides good electrical contact, while the composite copper-lithium sheet serves as the negative electrode material. On the other side of the SEM wafer, 20 mg of positive electrode active material is evenly distributed. The positive electrode material is brought into close contact with the SEM wafer. The mold containing all components is then placed in a press, and a pressure of 80 MPa is applied and maintained for several minutes to ensure thorough bonding between the layers, forming a single solid-state battery cell.

[0169] Example 2

[0170] The difference between Example 2 and Example 1 is that the structural formula of the dispersant is shown below, and the number-average molecular weight of the dispersant is 10875 g / mol.

[0171] The preparation method of the above dispersant includes the following steps: 8.61g of the first monomer of formula (a1), 31g of the second monomer of formula (b1), 69.1g of the second monomer of formula (c1) and 50g of ethanol are mixed, 1.1g of azobisisobutyronitrile is added, and the mixture is reacted at 70°C for 8h to obtain the above dispersant.

[0172] Example 3

[0173] The difference between Example 3 and Example 1 is that the structural formula of the dispersant is shown below, and the number-average molecular weight of the dispersant is 30470 g / mol.

[0174] The preparation method of the above dispersant includes the following steps: 8.61g of the first monomer of formula (a1), 31g of the second monomer of formula (b1), 69.1g of the second monomer of formula (c1) and 50g of ethanol are mixed, 0.55g of azobisisobutyronitrile is added, and the mixture is reacted at 65°C for 24h to obtain the above dispersant.

[0175] Example 4

[0176] The difference between Example 4 and Example 1 is that the dispersant has the following structural formula and the number-average molecular weight is 20148 g / mol. In the structure of the dispersant, the molar ratio of structural unit A, structural unit B of formula (4) and structural unit B of formula (11) is 1:6:3.

[0177] The preparation method of the above dispersant includes the following steps: 8.61g of the first monomer of formula (a1), 93g of the second monomer of formula (b1), 103.65g of the second monomer of formula (c1) and 102.6g of ethanol are mixed, 1g of azobisisobutyronitrile is added, and the mixture is reacted at 70°C for 12h to obtain the above dispersant.

[0178] Example 5

[0179] The difference between Example 5 and Example 4 is that the sulfide electrolyte material is Li. 5.5 PS5ClBr 0.5 The molecular formula of the dispersant is as follows, and the molecular weight of the dispersant is 30222 g / mol.

[0180] The preparation method of the above dispersant includes the following steps: 12.9g of the first monomer of formula (a1), 139.5g of the second monomer of formula (b1), 155.5g of the second monomer of formula (c1) and 154g of ethanol are mixed, 1.5g of azobisisobutyronitrile is added, and the mixture is reacted at 65°C for 24h to obtain the above dispersant.

[0181] Example 6

[0182] The difference between Example 6 and Example 1 is that the sulfide electrolyte material is Li. 10 GeP2S 12The number-average molecular weight of the dispersant is 21413 g / mol. The structural formula of the dispersant is as follows, which includes structural unit A as shown in formula (2) and structural unit B as shown in formula (4). The molar ratio of structural unit A to structural unit B in formula (4) is 1.5:8.5.

[0183] The preparation method of the above dispersant includes the following steps: 12.9g of the first monomer of formula (a1), 131.75g ​​of the second monomer of formula (b1) and 72.3g of ethanol are mixed, 0.7g of azobisisobutyronitrile is added, and the mixture is reacted at 70°C for 12h to obtain the above dispersant.

[0184] Example 7

[0185] The difference between Example 7 and Example 1 is that the sulfide electrolyte material is Li3PS4, the dispersant has the following structural formula, and the number-average molecular weight of the dispersant is 39613 g / mol. The structure of the dispersant includes structural unit A as shown in formula (2) and structural unit B as shown in formula (11), and the molar ratio of structural unit A to structural unit B of formula (11) is 2:8.

[0186] The preparation method of the above dispersant includes the following steps: 8.61g of the first monomer of formula (a1), 138.2g of the second monomer of formula (c1) and 73.4g of ethanol are mixed, 0.6g of azobisisobutyronitrile is added, and the mixture is reacted at 65°C for 24h to obtain the above dispersant.

[0187] Example 8

[0188] The difference between Example 8 and Example 6 is that the sulfide electrolyte material is Li7P3S. 11 The structural formula of the dispersant is shown below, and the number-average molecular weight of the dispersant is 50808 g / mol. The molar ratio of structural unit A to structural unit B of formula (11) is 1.5:8.5.

[0189] The preparation method of the above dispersant includes the following steps: 12.9g of the first monomer of formula (a1), 131.75g ​​of the second monomer of formula (b1) and 50g of ethanol are mixed, 0.5g of azobisisobutyronitrile is added, and the mixture is reacted at 60℃ for 24h to obtain the above dispersant.

[0190] Comparative Example 1

[0191] The difference between Comparative Example 1 and Example 1 is that the electrolyte material does not contain a dispersant.

[0192] Comparative Example 2

[0193] The difference between Comparative Example 2 and Example 6 is that the electrolyte material does not contain a dispersant.

[0194] Performance testing

[0195] To verify the progressiveness of the embodiments of this application, the samples of the embodiments and comparative examples were subjected to the following tests:

[0196] 1. Infrared spectroscopy test

[0197] The types and quantities of functional groups in the composite electrolyte material samples were measured using Fourier transform infrared spectroscopy (FTIR).

[0198] 2. Particle size distribution test

[0199] Take an appropriate amount (0.5g~1g) of composite electrolyte material sample, grind it initially, and add it into a Venturi tube (dispersion pressure 0.5bar~2bar). Select the dry method mode of Malvern laser particle size analyzer for testing, and you can obtain the particle size distribution curve and particle size value.

[0200] 3. Tensile strength test

[0201] Place the solid electrolyte membrane specimen in the two clamps of the tensile strength testing machine, ensuring the longitudinal axis of the specimen coincides with the line connecting the centers of the upper and lower clamps. Apply appropriate tightness to prevent the specimen from slipping or breaking within the clamps. Start the testing machine at a controlled speed. After the specimen breaks, record the breaking load and measure the specimen width and length. Calculate the tensile strength based on the load (N) / width (b) / thickness (d).

[0202] 4. Ionic conductivity testing of electrolyte materials

[0203] 120mg-150mg of composite electrolyte powder was pressed into tablets at 40MPa in a mold, and impedance testing was performed. The ionic conductivity was calculated based on the impedance value and the layer thickness.

[0204] 5. Ionic conductivity testing of solid electrolyte membranes

[0205] Solid electrolyte membrane discs are compacted in a mold at 40–80 MPa, and impedance tests are performed. The ionic conductivity is calculated based on the impedance value and layer thickness.

[0206] 6. Battery performance test

[0207] The solid-state battery cells prepared above were charged to 4.3V at 0.33C under a constant temperature environment of 25℃, and then charged at a constant voltage of 4.3V until the current ≤0.05C. After standing for 5 minutes, they were discharged to 2.6V at 0.33C. The specific capacity of the battery cells in the first discharge cycle, the first efficiency (first charge and discharge efficiency), and the capacity retention rate after 100 cycles were tested. The first charge and discharge efficiency = (first discharge capacity / first charge capacity) × 100%; the capacity retention rate = (discharge capacity of the 100th cycle / first discharge capacity) × 100%.

[0208] Table 1 shows the ionic conductivity and particle size of the electrolyte materials in each embodiment and comparative example at the time of preparation and after 90 days of storage.

[0209] Table 1

[0210] Table 2 shows the conductivity, tensile strength, and solid-state battery cell performance of the electrolyte materials of each embodiment and comparative example after being stored for 90 days and then prepared into solid electrolyte membranes.

[0211] Table 2

[0212] Based on the analysis and test results in Tables 1 and 2, for the same chemical formula sulfide electrolyte Li6PS5Cl, there was no significant difference in particle size between Example 1 at the time of preparation and after 90 days of static storage. Since the two curves almost completely overlap, the particle size distribution diagram of Example 1 at the time of preparation is not shown. However, Comparative Example 1 showed a large difference in particle size at the time of preparation and after 90 days of static storage. This difference was due to particle agglomeration caused by electrostatic force or water adsorption. The electrolyte membrane made from Li6PS5Cl without dispersant in Comparative Example 1 had reduced strength and contained internal defects after the particles increased in size, resulting in poorer cycle stability of the battery compared to the sample with dispersant.

[0213] The dispersant in this embodiment exhibits good stability for sulfide electrolytes. It does not chemically react with sulfide electrolytes, and its polymeric network block structure can effectively prevent the sulfide electrolyte from absorbing water spatially. It also has wettability, which can reduce the surface energy of sulfide electrolyte particles, thereby preventing them from agglomerating during storage. This improves the uniformity of the prepared sulfide electrolyte film, reduces defects, enhances mechanical strength, and enables batteries using it to have better cycle stability.

[0214] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not 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. These 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, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

A solid-state battery cell, characterized in that, The invention includes a solid electrolyte membrane, wherein the solid electrolyte membrane comprises a composite electrolyte material, the composite electrolyte material comprises a sulfide electrolyte and a dispersant, the molecular structure of the dispersant containing structural unit A and structural unit B, wherein the structural formula of structural unit A is shown in Formula I; and the structural formula of structural unit B is shown in Formula II and / or Formula III. R1, R3, and R5 are each independently selected from hydrogen and C1 to C6 alkyl groups; R2 is selected from C2~C 20 alkyl; R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups. The solid-state battery cell according to claim 1 is characterized in that, The molecular structure of the dispersant is shown in Formula IV: Where 10≤n≤100, 20≤m≤400, and 20≤f≤400. The solid-state battery cell according to claim 1 or 2 is characterized in that, R1, R3, and R5 are each independently selected from hydrogen or methyl; R2 is selected from one of C4-C6 alkyl groups; R4 is selected from C... 14 ~C 16 One of the alkyl groups. The solid-state battery cell according to any one of claims 1 to 3 is characterized in that, The molar ratio of structural unit A to structural unit B is 1:9 to 2:

8. The solid-state battery cell according to any one of claims 2 to 4 is characterized in that, The ratio of n, m and f ranges from 1:(2 to 4):(2 to 4). The solid-state battery cell according to any one of claims 1 to 5 is characterized in that, The number-average molecular weight Mn of the dispersant is 10000 g / mol to 60000 g / mol. The solid-state battery cell according to any one of claims 1 to 6 is characterized in that, The weight of the dispersant accounts for 0.1% to 1.5% of the total weight of the composite electrolyte material. The solid-state battery cell according to any one of claims 1 to 7 is characterized in that, The sulfide electrolyte includes Li 7-a PS5X a Li 10 MP2S 12 Li3PS4, Li7P3S 11 Li7P2S8Cl2, Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 At least one of the following: where 0 ≤ a ≤ 1.5, X is at least one of F, Cl, Br, I, and M is at least one of Ge, Si, Sn. The solid-state battery cell according to any one of claims 1 to 8 is characterized in that, The composite electrolyte material D V 50 Particle size ≤ 2μm, D V 90 Particle size < 5 μm. The solid-state battery cell according to any one of claims 1 to 9 is characterized in that, The thickness of the solid electrolyte membrane is 30 μm to 100 μm. A composite electrolyte material, characterized in that, The mixture includes a sulfide electrolyte and a dispersant, wherein the molecular structure of the dispersant contains structural unit A and structural unit B, wherein the structural formula of structural unit A is shown in Formula I; and the structural formula of structural unit B is shown in Formula II and / or Formula III. R1, R3, and R5 are each independently selected from hydrogen and C1 to C6 alkyl groups; R2 is selected from C2~C 20 alkyl; R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups. The composite electrolyte material according to claim 11 is characterized in that, The molecular structure of the dispersant is shown in Formula IV: Where 10≤n≤100, 20≤m≤400, and 20≤f≤400. The composite electrolyte material according to claim 11 or 12 is characterized in that, R1, R3, and R5 are each independently selected from hydrogen or methyl; R2 is selected from one of C4-C6 alkyl groups; R4 is selected from C... 14 ~C 16 One of the alkyl groups. The composite electrolyte material according to any one of claims 11 to 13 is characterized in that, The molar ratio of structural unit A to structural unit B is 1:9 to 2:

8. The composite electrolyte material according to any one of claims 12 to 14 is characterized in that, The ratio of n, m and f ranges from 1:(2 to 4):(2 to 4). The composite electrolyte material according to any one of claims 11 to 15 is characterized in that, The composite electrolyte material satisfies at least one of (1) to (4): (1) The number average molecular weight Mn of the dispersant is 10000 g / mol to 60000 g / mol; (2) The weight of the dispersant accounts for 0.1% to 1.5% of the total weight of the composite electrolyte material; (3) The sulfide electrolyte includes Li 7-a PS5X a Li 10 MP2S 12 Li3PS4, Li7P3S 11 Li7P2S8Cl2, Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 At least one of the following: where 0 ≤ a ≤ 1.5, X is at least one of F, Cl, Br, I, and M is at least one of Ge, Si, Sn; (4) D of the composite electrolyte material V 50 Particle size ≤ 2μm, D V 90 Particle size < 5 μm. A method for preparing a composite electrolyte material, characterized in that, Includes the following steps: The composite electrolyte material is obtained by mixing a sulfide electrolyte, a dispersant, and a solvent, followed by heat treatment; wherein the molecular structure of the dispersant contains structural unit A and structural unit B, the structural formula of structural unit A is shown in Formula I; the structural formula of structural unit B is shown in Formula II and / or Formula III. R1, R3, and R5 are each independently selected from hydrogen and C1 to C6 alkyl groups; R2 is selected from C2~C 20 alkyl; R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups. The method for preparing the composite electrolyte material according to claim 17 is characterized in that, The solvent includes at least one of thiol, xylene, toluene, n-heptane, n-decane, n-octane, n-nonane, butyl butyrate, and pentyl valerate. The method for preparing the composite electrolyte material according to claim 18 is characterized in that, The solvent includes methylbenzene and butyl butyrate, wherein the volume ratio of methylbenzene to butyl butyrate is 3:7 to 7:3; Alternatively, the solvent may include n-heptane and butyl butyrate, wherein the volume ratio of n-heptane to butyl butyrate is 3:7 to 7:

3. The method for preparing the composite electrolyte material according to any one of claims 17 to 19 is characterized in that, The mixing process includes grinding the sulfide electrolyte, the dispersant, and the solvent. The grinding conditions include a ball milling speed of 400 rpm to 600 rpm and a ball milling time of 5 h to 10 h. The method for preparing the composite electrolyte material according to any one of claims 17 to 20 is characterized in that, The heat treatment includes heating at 80°C to 120°C for 4 to 12 hours under an inert atmosphere. The method for preparing the composite electrolyte material according to any one of claims 17 to 21 is characterized in that, The dispersant is formed by polymerizing monomers in the presence of an initiator; The polymeric monomers include a first monomer and a second monomer, wherein the structural formula of the first monomer is shown in formula (a), and the structural formula of the second monomer is shown in formula (b) and / or formula (c): R1, R3, and R5 are each independently selected from hydrogen and C1 to C6 alkyl groups; R2 is selected from C2~C 20 alkyl; R4 is selected from hydrogen, C1 to C2. 20 One of the alkyl groups. A battery device, characterized in that, Includes solid-state battery cells according to any one of claims 1 to 10. An electrical device, characterized in that, Includes a solid-state battery cell according to any one of claims 1 to 10 or a battery device according to claim 23, wherein the solid-state battery cell or the battery device is used to store or provide electrical energy.

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