Solid electrolyte and preparation method thereof, battery, battery assembly and electric device

Abstract

The invention relates to the field of batteries, in particular to a solid electrolyte, a preparation method of the solid electrolyte, a battery, a battery assembly and an electric device. The coating layer is arranged on the surface of the solid electrolyte main body, the coating layer contains a coating agent, the coating agent contains hydrophobic groups and heteroatom groups, and heteroatoms in the heteroatom groups comprise at least one of N, P, S and O. The solid electrolyte has excellent air stability.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to solid electrolytes and their preparation methods, batteries, battery components, and electrical devices. Background Technology

[0002] All-solid-state batteries offer higher safety, energy density, and cycle life, and are considered a crucial direction for the development of next-generation battery technology. However, the solid electrolytes used in all-solid-state batteries are prone to hygroscopic reactions when exposed to moisture in the air, leading to a decline in their electrochemical performance or even failure. Therefore, effectively isolating the solid electrolyte from moisture in the air has become a key research issue in this field.

[0003] Currently, the main methods to solve this problem are physical encapsulation or the introduction of desiccant to isolate moisture. However, these methods all have certain limitations, such as complex encapsulation processes and the potential impact of desiccant introduction on electrochemical performance. Therefore, technologies to improve the air stability of solid electrolytes still need further development.

[0004] Application content

[0005] This application aims to at least partially address one of the technical problems in the related art. To this end, this application proposes a solid electrolyte with excellent air stability, a method for preparing the same, a battery, a battery assembly, and an electrical device thereof.

[0006] In a first aspect, this application provides a solid electrolyte. According to an embodiment of this application, the solid electrolyte includes: a solid electrolyte body; and a coating layer disposed on the surface of the solid electrolyte body. The coating layer contains a coating agent, which contains hydrophobic groups and heteroatom groups. The heteroatoms in the heteroatom groups include at least one of N, P, S, and O. In this solid electrolyte, the heteroatom groups in the coating agent can adhere to the surface of the solid electrolyte body through coordination with metal cations in the solid electrolyte body and intermolecular forces, while the hydrophobic groups in the coating agent can effectively resist the erosion of the solid electrolyte body by moisture in the air, thereby giving the solid electrolyte excellent air stability.

[0007] According to embodiments of this application, the heteroatom in the heteroatom group includes S.

[0008] According to embodiments of this application, the heteroatom groups include at least one of thioether groups, thiols, thioester groups, thioketone groups, thioacyl groups, phosphate ester groups, carboxylic acid ester groups, and amino groups, specifically including at least one of thioether groups, thiols, thioester groups, thioketone groups, and thioacyl groups.

[0009] According to embodiments of this application, the hydrophobic group includes at least one of C5-C30 alkyl, fluorinated alkyl, siloxane group, and substituted alkyl containing benzene ring and / or heterocyclic structure.

[0010] According to an embodiment of this application, the solid electrolyte body comprises a sulfide solid electrolyte.

[0011] According to embodiments of this application, the sulfide solid electrolyte includes a sulfide-germanium ore type electrolyte Li. n PS m X, where n is 5 to 7, m is 4 to 6, and X includes at least one of Cl, Br, and I.

[0012] According to embodiments of this application, the coating agent includes at least one of undecyl mercaptan, dodecyl mercaptan, dodecyl sulfide, dodecyl methyl sulfide, bis(dodecyl disulfide), tetradecyl mercaptan, hexadecyl sulfide, di(octadecyl) disulfide, docosyl mercaptan, dodecyl trimethoxysilane, octadecyl trimethoxysilane, dodecyl phosphate, bis(2-ethylhexyl) phosphate, and C8-C18 perfluoroalkyl phosphate. Specifically, it may include at least one of undecyl mercaptan, dodecyl mercaptan, dodecyl sulfide, dodecyl methyl sulfide, bis(dodecyl disulfide), tetradecyl mercaptan, hexadecyl sulfide, di(octadecyl) disulfide, and docosyl mercaptan.

[0013] According to an embodiment of this application, the heteroatom groups are adsorbed on the surface of the solid electrolyte host, and the molecular chains of the coating agent are arranged radially along the solid electrolyte host.

[0014] According to an embodiment of this application, the mass ratio of the coating layer to the mass of the solid electrolyte body is 0.0001 to 0.1.

[0015] A second aspect of this application provides a method for preparing the aforementioned solid electrolyte. According to an embodiment of this application, the method includes: stirring and mixing a solid electrolyte substrate and a coating agent, causing the coating agent to adsorb onto the surface of the solid electrolyte substrate, thereby obtaining the solid electrolyte. This method is simple and convenient to operate, and the solid electrolyte prepared exhibits excellent air stability.

[0016] According to an embodiment of this application, the method includes: stirring and mixing a solid electrolyte substrate, a coating agent, and a dispersant to obtain a first mixture; removing the dispersant from the first mixture to obtain the solid electrolyte.

[0017] According to an embodiment of this application, the step of mixing the solid electrolyte substrate, coating agent, and dispersant includes: mixing and stirring the coating agent and the dispersant to obtain a second mixture; mixing the second mixture with the solid electrolyte substrate and stirring at 40°C to 120°C to obtain a first mixture.

[0018] According to an embodiment of this application, the ratio of the solid electrolyte body, the coating agent, and the dispersant is 100g: 0.01-10g: 400-600ml.

[0019] According to embodiments of this application, the dispersant includes at least one selected from toluene, o-xylene, m-xylene, p-xylene, benzene, mesitylene, n-heptane, n-hexane, n-octane, n-nonane, n-decane, cyclohexane, cyclopentane, methylcyclohexane, ethylcyclohexane, dimethylbenzene, dimethylformamide, and dimethyl sulfoxide.

[0020] According to embodiments of this application, the moisture content of the dispersant is no more than 100 ppm, preferably no more than 20 ppm.

[0021] According to an embodiment of this application, the dispersant in the mixture is removed by a reduced pressure evaporation method.

[0022] According to an embodiment of this application, the method further includes: after removing the dispersant from the mixture, drying the product after removing the dispersant to obtain the solid electrolyte.

[0023] A third aspect of this application provides a battery. According to an embodiment of this application, the battery includes the solid electrolyte described above. This battery can have better safety and a longer service life.

[0024] In a fourth aspect, this application provides a battery assembly. According to embodiments of this application, it includes the solid-state electrolyte described above, the solid-state electrolyte prepared by the methods described above, or the battery described above. This battery assembly exhibits improved stability and safety.

[0025] A fifth aspect of this application provides an electrical device. According to embodiments of this application, the electrical device includes the solid electrolyte described above, the solid electrolyte prepared by the method described above, the battery described above, or the battery assembly described above. This electrical device exhibits improved stability and safety. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a solid electrolyte according to an embodiment of this application.

[0027] Figure 2 This is a schematic diagram of the structure of a solid electrolyte according to another embodiment of this application.

[0028] Figure label:

[0029] 10: Solid electrolyte body; 20: Coating layer; 21: Inner layer; 22: Outer layer Detailed Implementation

[0030] The embodiments of this application are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0031] In a first aspect, this application provides a solid electrolyte. According to an embodiment of this application, referring to... Figure 1 The solid electrolyte comprises: a solid electrolyte body 10; and a coating layer 20 disposed on the surface of the solid electrolyte body 10. The coating layer 20 contains a coating agent, which contains hydrophobic groups and heteroatom groups. The heteroatoms in the heteroatom groups include at least one of N, P, S, and O. In this solid electrolyte, the heteroatom groups in the coating agent can adhere to the surface of the solid electrolyte body through coordination with metal cations in the solid electrolyte body and intermolecular forces, while the hydrophobic groups in the coating agent can effectively resist the erosion of the solid electrolyte body by moisture in the air, thus giving the solid electrolyte excellent air stability.

[0032] According to embodiments of this application, the heteroatoms in the heteroatom groups include S. Therefore, by utilizing -SR (R = S, H, O-CO, C, O, etc.) bonds, sulfur atoms can coordinate with metal cations in the solid electrolyte matrix, and by utilizing hydrophobic groups to resist the erosion of the electrolyte matrix by moisture in the air, the air stability of the electrolyte matrix can be better improved.

[0033] According to embodiments of this application, the heteroatom groups include at least one selected from thioether groups, thiol groups, thioester groups, thionyl groups, thioketone groups, thioacryl groups, phosphate ester groups, carboxylic acid ester groups, and amino groups. This allows for better adhesion of the heteroatoms to the surface of the solid electrolyte host through coordination with metal cations in the solid electrolyte host, intermolecular forces, etc.

[0034] As an example, heteroatomic groups include at least one of thioether groups, thiols, thioester groups, thioketone groups, and thioacryl groups. Therefore, the S atom exhibits stronger coordination with the metal cations in the solid electrolyte matrix, as well as stronger intermolecular forces, adhering to the surface of the solid electrolyte matrix and thus improving the air stability of the electrolyte matrix.

[0035] According to embodiments of this application, the hydrophobic group includes at least one of C5-C30 alkyl groups, fluorinated alkyl groups, siloxane groups, and substituted alkyl groups containing benzene rings and / or heterocyclic structures. Specifically, the hydrophobic group can form a hydrophobic layer on the outer surface of the solid electrolyte host, thereby effectively resisting the impact of H2O in the air on the solid electrolyte host and improving the air stability of the solid electrolyte host.

[0036] In this article, the term "alkyl" refers to a saturated straight-chain, branched, or cyclic monovalent hydrocarbon group with 5 to 30 carbon atoms (alkyl is C5-C30 alkyl), including but not limited to n-pentyl, isopentyl, secondary pentyl, tert-pentyl, neopentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 2-methyl-2-ethylpropyl, etc.

[0037] The term "fluorinated alkyl" refers to an alkyl group in which at least one hydrogen atom is replaced by a fluorine atom.

[0038] The term "siloxane group" refers to an organosilicon group linked by Si-O-Si bonds, with the core structure being [-Si(R2-O)-]n (where R2 is an organic group, such as alkyl, fluorinated alkyl, etc.).

[0039] The term "substituted alkyl group containing benzene rings and / or heterocyclic structures" refers to an alkyl group in which hydrogen atoms are replaced by benzene rings and / or heterocyclic structures.

[0040] In this article, the number of carbon atoms in the hydrophobic groups can be no less than 5. The hydrophobic groups include at least one of the following: alkyl groups with no less than 5 carbon atoms, fluoroalkyl groups with no less than 5 carbon atoms, siloxane groups with no less than 5 carbon atoms, and substituted alkyl groups with no less than 5 carbon atoms containing benzene rings and / or heterocyclic structures.

[0041] According to an embodiment of this application, the heteroatomic groups are adsorbed on the surface of the solid electrolyte host, and the molecular chains of the coating agent are arranged radially along the solid electrolyte host. Thus, a double-layer coating structure can be formed on the surface of the solid electrolyte host, i.e., the heteroatomic groups face the solid electrolyte host, and there is coordination and / or intermolecular forces between the heteroatomic groups and the solid electrolyte host. The heteroatomic groups, closer to the solid electrolyte host, constitute the inner layer 21 of the coating layer, while the hydrophobic groups, farther from the solid electrolyte host, constitute the outer layer 22 of the coating layer. A schematic diagram can be found [reference needed]. Figure 2 .

[0042] Understandable. Figure 2 The diagram shows a relatively ideal state. In practical applications, it is inevitable that some of the coating agent's molecular chains will not be aligned in the radial direction. As long as most of the coating agent's molecular chains are aligned in the radial direction, it is acceptable.

[0043] According to embodiments of this application, the specific type of the solid electrolyte substrate can be selected based on actual use. In some embodiments, the solid electrolyte substrate may include a sulfide solid electrolyte. Therefore, solid electrolytes possess advantages such as high ionic conductivity, high energy density, good mechanical properties and flexibility, good interfacial compatibility, high safety, and controllable cost.

[0044] According to embodiments of this application, the sulfide solid electrolyte may include a sulfide-germanium ore type electrolyte Li n PS m X, where n is 5–7, m is 4–6, and X includes at least one of Cl, Br, and I. Therefore, the ionic conductivity, interfacial compatibility, electrochemical stability, and safety of solid electrolytes can be further improved, while maintaining a lower cost.

[0045] It is understood that the above-mentioned silver-germanium sulfide electrolyte can be prepared by conventional wet or dry processes, or it can be obtained by purchase; this application does not impose any specific restrictions.

[0046] According to embodiments of this application, the coating agent may include at least one of undecyl mercaptan, dodecyl mercaptan, dodecyl sulfide, dodecyl methyl sulfide, bis(dodecyl disulfide), tetradecyl mercaptan, hexadecyl sulfide, di(octadecyl) disulfide, dodecyl mercaptan, dodecyl trimethoxysilane, octadecyl trimethoxysilane, dodecyl phosphate, bis(2-ethylhexyl) phosphate, and C8-C18 perfluoroalkyl phosphate. Therefore, it can firmly adhere to the surface of the solid electrolyte substrate, exhibiting a good coating effect, forming a dense hydrophobic layer that isolates moisture and oxygen, thereby effectively improving the air stability of the solid electrolyte.

[0047] As an example, the coating agent may include at least one of undecyl mercaptan, dodecyl mercaptan, dodecyl sulfide, dodecyl methyl sulfide, didodecyl disulfide, tetradecyl mercaptan, hexadecyl sulfide, di(octadecyl) disulfide, and docosyl mercaptan. Therefore, the coating agent can better coordinate with the metal ions in the solid electrolyte matrix, strengthening the connection between the coating agent and the solid electrolyte matrix. Simultaneously, the hydrophobic groups can form a dense hydrophobic layer on the outer surface of the solid electrolyte matrix, effectively resisting the impact of water in the air on the solid electrolyte matrix and further improving the air stability of the solid electrolyte matrix.

[0048] According to embodiments of this application, further adjusting the mass ratio of the coating layer to the solid electrolyte bulk can effectively improve the air stability of the solid electrolyte while maintaining good ionic conductivity. In some embodiments, the mass ratio of the coating layer to the solid electrolyte bulk is 0.0001 to 0.1, specifically 0.0001, 0.0005, 0.001, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc. A ratio within the above range can effectively improve the air stability of the solid electrolyte without excessively reducing its ionic conductivity.

[0049] A second aspect of this application provides a method for preparing the aforementioned solid electrolyte. According to an embodiment of this application, the method includes: stirring and mixing a solid electrolyte substrate and a coating agent, causing the coating agent to adsorb onto the surface of the solid electrolyte substrate, thereby obtaining the solid electrolyte. This method is simple and convenient to operate, and the solid electrolyte prepared exhibits excellent air stability.

[0050] According to an embodiment of this application, the method includes: stirring and mixing a solid electrolyte substrate, a coating agent, and a dispersant to obtain a first mixture; removing the dispersant from the first mixture to obtain the solid electrolyte. This method is simple and convenient to operate, and the solid electrolyte prepared from it exhibits excellent air stability.

[0051] According to embodiments of this application, in the above-described stirring and mixing step, the coating agent and dispersant can be mixed first and stirred for 30 to 90 minutes (specifically, 30, 40, 50, 60, 70, 80, 90 minutes, etc.) to ensure thorough homogeneity. Then, the resulting second mixture is mixed with the solid electrolyte and stirred at 40°C to 120°C (specifically, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 70, 80, 90, 100, 110, 120°C, etc.) for 30 to 90 minutes (specifically, 30, 40, 50, 60, 70, 80, 90 minutes, etc.) to ensure uniform dispersion of all components, resulting in the first mixture. In the above steps, the heteroatomic groups in the coating agent can effectively adhere to the surface of the solid electrolyte matrix, forming a coating layer.

[0052] According to embodiments of this application, the solid electrolyte substrate, the coating agent, and the dispersant can be mixed in a ratio of 100g:0.01-10g:400-600ml, specifically 100g:0.01g:500ml, 100g:0.05g:500ml, 100g:0.1g:500ml, 100g:1g:500ml, 100g:2g:500ml, etc. 00g:3g:500ml, 100g:4g:500ml, 100g:5g:500ml, 100g:6g:500ml, 100g:7g:500ml, 100g:8g:500ml, 100g:9g:500ml, 100g:10g:500ml, 100g:0.01g:400ml, 100g:0.01g:600ml, etc. This effectively improves the air stability of the solid electrolyte without excessively reducing its ionic conductivity.

[0053] According to embodiments of this application, dispersing the solid electrolyte substrate and the coating agent in a dispersant can effectively promote the uniform adhesion of the coating agent to the surface of the solid electrolyte substrate. Specifically, a non-polar or low-polarity dispersant can be used, thereby reducing side reactions and keeping the solid electrolyte substrate stable.

[0054] In some embodiments, the dispersant may include at least one selected from toluene, o-xylene, m-xylene, p-xylene, benzene, mesitylene, n-heptane, n-hexane, n-octane, n-nonane, n-decane, cyclohexane, cyclopentane, methylcyclohexane, ethylcyclohexane, dimethylbenzene, dimethylformamide, and dimethyl sulfoxide. This allows for better dispersion of the solid electrolyte bulk and the coating agent, while minimizing side reactions.

[0055] It is understood that solid electrolytes readily react with moisture in the air, reducing their electrochemical stability. Therefore, side reactions can be further reduced by controlling the moisture content in the dispersant. In some embodiments, the moisture content of the dispersant is no more than 100 ppm, specifically no more than 20 ppm. This further reduces side reactions and improves the electrochemical stability of the solid electrolyte during preparation.

[0056] In this paper, the moisture content of the dispersant can be detected using a Karl Fischer moisture analyzer.

[0057] In some embodiments, to further ensure the performance of the solid electrolyte, the dispersant can be dried before use. Specific drying methods include, but are not limited to, rotary evaporation, molecular sieve drying, or other suitable drying methods, to ensure the moisture content meets the aforementioned requirements. In some embodiments, a dehydrating agent, such as sodium sulfate or anhydrous magnesium sulfate, can be added to the dispersant to further reduce its moisture content. This ensures the purity and performance of the dispersant, thereby improving the quality and stability of the final solid electrolyte, while ensuring that these dispersants do not negatively impact the performance of the solid electrolyte.

[0058] According to embodiments of this application, the specific method for removing the dispersant may include vacuum distillation. This is simple and convenient, yields a solid electrolyte with better performance, and avoids the adverse effects of residual dispersant on the solid electrolyte's performance.

[0059] According to embodiments of this application, after removing the dispersant, the product obtained after removing the dispersant can be dried (e.g., placed in a vacuum drying oven). This further removes any residual moisture, further ensuring the high quality and stability of the solid electrolyte.

[0060] It is understandable that solid electrolytes are prone to react with moisture, which reduces their electrochemical stability. Therefore, the prepared solid electrolytes can be stored in a glove box filled with inert gas to ensure that their stability and performance are not affected by the external environment, thus ensuring the high quality and stability of the solid electrolytes.

[0061] A third aspect of this application provides a battery. According to an embodiment of this application, the battery includes the solid electrolyte described above. This battery can have better safety and a longer service life.

[0062] It is understandable that the specific type of battery is not particularly limited; it can be a primary battery, a secondary battery, a lithium-ion battery, a sodium-ion battery, etc.; the shape of the battery can be cylindrical, square, or any other shape; and according to the outer packaging, the battery can be a hard-shell battery, a soft-pack battery, etc.

[0063] Typically, a battery includes a positive electrode, a negative electrode, and a solid electrolyte located between the positive and negative electrodes. Depending on the specific application, a separator may also be included. The positive electrode, negative electrode, and solid electrolyte can be manufactured into a cell using winding or stacking processes, and the cell can be housed in an outer package. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and extracting. The solid electrolyte acts as a conductor of ions between the positive and negative electrodes and also prevents short circuits between them.

[0064] The positive electrode in the battery may include a positive current collector and a positive active material layer, wherein the positive active material layer is disposed on at least one surface of the positive current collector.

[0065] In some embodiments, the positive current collector can be a metal current collector or a composite current collector. For example, metal current collectors include, but are not limited to, aluminum foil current collectors; composite current collectors may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0066] In some embodiments, the positive electrode active material layer may include positive electrode active material, binder and conductive agent, and may also include additives with specific functions and effects, such as thickeners, sodium supplements, film-forming additives, flame retardants, high temperature / low temperature stabilizers, etc., as needed.

[0067] As an example, the positive electrode active material of the battery may include lithium nickel cobalt manganese oxide (including but not limited to NCM811, NCM613, NCM523, etc.), lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium nickel manganese oxide, lithium-rich manganese-based materials, or positive electrode active materials commonly used in the art.

[0068] As an example, the binder in the positive electrode active material layer may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0069] As an example, the conductive agent in the positive electrode active material layer may include at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0070] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a layer of negative electrode active material disposed on at least one side surface of the negative electrode current collector.

[0071] As an example, the negative electrode active material layer may include a negative electrode active material, a thickener, a conductive agent, and a binder, wherein the negative electrode current collector may be a metal foil, for example, a copper foil.

[0072] According to embodiments of this application, the negative electrode active material may include carbon-based materials, silicon-based materials, tin-based materials, etc.

[0073] According to embodiments of this application, the binder in the negative electrode material layer may include, but is not limited to, at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethyl methacrylate (PMAA), and carboxymethyl chitosan (CMCS).

[0074] According to embodiments of this application, the conductive agent in the negative electrode material layer may include, but is not limited to, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0075] In some embodiments, the separator may be a separator known in the art that can be used in lithium-ion batteries and is stable to the electrolyte used, such as a polyethylene separator, a polypropylene separator, a polyethylene / polypropylene composite separator, etc.

[0076] In a fourth aspect, this application provides a battery assembly. According to embodiments of this application, it includes the solid-state electrolyte described above, the solid-state electrolyte prepared by the methods described above, or the battery described above. This battery assembly exhibits improved stability and safety.

[0077] It is understood that the battery assembly can be a battery module, a battery pack, etc. Specifically, the specific structure of the battery module and battery pack can be found in conventional technology in this field, and will not be described in detail here.

[0078] A fifth aspect of this application provides an electrical device. According to embodiments of this application, the electrical device includes the solid electrolyte described above, the solid electrolyte prepared by the method described above, the battery described above, or the battery assembly described above. This electrical device exhibits improved stability and safety.

[0079] According to embodiments of this application, the specific type of electrical device is not particularly limited and can be any device that uses a battery as a power source or energy storage unit. As examples, electrical devices include, but are not limited to, electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), mobile terminals (e.g., mobile phones, laptops, game consoles, wearable devices, etc.), drones, aerospace equipment, satellites, ships, energy storage systems, and so on.

[0080] It is understandable that, in addition to the battery mentioned above, the electrical device also includes necessary structures and components, all of which can be made with reference to conventional technologies. For example, an electric vehicle may include a body, chassis, tires, navigation system, radar system, steering system, braking system, lubrication system, cooling system, driving system, etc., which will not be described in detail here.

[0081] The embodiments of this application are described in detail below.

[0082] Example 1

[0083] This embodiment provides a method for preparing a sulfide solid electrolyte, comprising the following steps:

[0084] Step 1: Add 0.75g of dodecyl mercaptan to 250mL of xylene solution and stir thoroughly for 60min to completely dissolve it, thus obtaining a mixed solution;

[0085] Step 2: Take 50g of Li6PS5Cl and mix it with the mixed solution from Step 1. Continue stirring at 50℃ for 60min to ensure that dodecyl mercaptan can be fully mixed with Li6PS5Cl.

[0086] Step 3: Remove xylene, which serves as a dispersant, by vacuum distillation at 100°C. Then, transfer the solid product after vacuum distillation to a vacuum oven and dry it at 100°C for more than 24 hours to completely remove xylene, obtaining a solid electrolyte of Li6PS5Cl coated with dodecyl mercaptan.

[0087] Example 2

[0088] This embodiment provides a method for preparing a sulfide electrolyte, including the following steps.

[0089] Step 1: Add 1.5g of dodecyl mercaptan to 250mL of xylene solution and stir thoroughly for 60min to dissolve completely, thus obtaining a mixed solution;

[0090] Step 2: Take 50g of the sulfide solid electrolyte host Li6PS5Cl and mix it with the mixed solution in Step 1. Continue stirring at 50℃ for 60min to ensure that the dodecyl mercaptan and Li6PS5Cl are fully mixed.

[0091] Step 3: Remove xylene, which serves as a dispersant, by vacuum distillation at 100°C. Then, transfer the solid product after vacuum distillation to a vacuum oven and dry it at 100°C for more than 24 hours to completely remove xylene, obtaining a solid electrolyte of Li6PS5Cl coated with dodecyl mercaptan.

[0092] Example 3

[0093] Same as Example 1, except that dodecyl mercaptan is replaced with tetradecyl mercaptan in the first step.

[0094] Example 4

[0095] Same as Example 1, except that dodecyl mercaptan is replaced with dodecyl sulfide in the first step.

[0096] Example 5

[0097] Same as Example 1, except that dodecyl mercaptan is replaced with dodecyl phosphate in the first step.

[0098] Example 6

[0099] Same as Example 1, except that dodecyl mercaptan in the first step is replaced with bis(2-ethylhexyl) phosphate.

[0100] Example 7

[0101] Same as Example 1, except that dodecylthiol in the first step is replaced with dodecyltrimethoxysilane.

[0102] Example 8

[0103] Same as Example 1, except that dodecyl mercaptan in the first step is replaced with octadecyltrimethoxysilane.

[0104] Example 9

[0105] Same as Example 1, except that dodecylthiol in the first step is replaced with perfluorodecyl phosphate.

[0106] Example 10

[0107] Same as Example 1, except that xylene in the first step is replaced with anisole.

[0108] Example 11

[0109] Same as Example 1, except that xylene in the first step is replaced with n-heptane.

[0110] Example 12

[0111] Same as Example 1, except that Li6PS5Cl in the second step is replaced with Li 5.5 PS 4.5 Cl 1.5 .

[0112] Example 13

[0113] Same as Example 1, except that Li6PS5Cl in the second step is replaced with Li 5.5 PS 4.5 ClBr 0.5

[0114] Comparative Example 1

[0115] Same as Example 1, except that dodecanethiol in the first step is replaced with dimethyl sulfate.

[0116] Comparative Example 2

[0117] Same as Example 1, except that dodecanethiol in the first step is replaced with triethanolamine.

[0118] Comparative Example 3

[0119] Li6PS5Cl was used directly as the solid electrolyte.

[0120] Table 1

[0121]

[0122]

[0123] Performance testing:

[0124] The ionic conductivity test method is as follows: Take 150 mg of electrolyte material and place it in a Swagelok battery (the electrodes at both ends are made of stainless steel, the middle shell is made of polytetrafluoroethylene, and the powder is placed in the shell). Measure the thickness D1 of the electrolyte membrane using vernier calipers. Next, assemble the test device and apply a pressure of 5 tons, connect the test fixture, measure its AC impedance, and record the intersection of the curve and the X-axis, i.e., the resistance value Ω. After disconnecting the test device, release the pressure, and measure the thickness D2 and area S of the electrolyte membrane again using vernier calipers. Finally, calculate the ionic conductivity according to the formula σ = (D2 - D1) / (S × Ω). Following the above method, test the ionic conductivity of the solid electrolytes in the above examples and comparative examples before and after exposure in a -40°C dew point environment. The test results are shown in Table 2.

[0125] The specific operation for exposure in a -40℃ dew point environment is as follows: Connect the online dew point meter to the multi-functional glove box, and continuously introduce inert gas (such as argon or nitrogen) to lower the dew point inside the chamber to -40℃. The specific steps are as follows: First, ensure a stable and reliable connection between the online dew point meter and the multi-functional glove box. Then, start the inert gas supply system and continuously introduce inert gas to lower the dew point inside the chamber to -40℃. Next, place 500mg of solid electrolyte inside the chamber and expose it under these conditions for 1 hour to ensure the electrolyte material is sufficiently stable in a low-humidity environment. After exposure, use the battery assembly method described above to test the ionic conductivity of the exposed electrolyte material to evaluate its performance changes under low-humidity conditions.

[0126] Table 2: Changes in ionic conductivity before and after exposure to a -40℃ dew point environment

[0127]

[0128] The experimental data above show that the air stability of the solid electrolyte in this embodiment is significantly improved.

[0129] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0130] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0131] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A solid electrolyte, characterized in that, include: Solid electrolyte substrate; A coating layer is disposed on the surface of the solid electrolyte body. The coating layer contains a coating agent, which contains hydrophobic groups and heteroatom groups. The heteroatoms in the heteroatom groups include at least one of N, P, S and O.

2. The solid electrolyte according to claim 1, characterized in that, The heteroatom in the heteroatom group includes S.

3. The solid electrolyte according to claim 1 or 2, characterized in that, The heteroatom groups include at least one of thioether groups, thiols, thioester groups, thioketone groups, thioacyl groups, phosphate ester groups, carboxylic acid ester groups, and amino groups, preferably including at least one of thioether groups, thiols, thioester groups, thioketone groups, and thioacyl groups.

4. The solid electrolyte according to any one of claims 1 to 3, characterized in that, The hydrophobic group includes at least one of C5-C30 alkyl, fluorinated alkyl, siloxane group, and substituted alkyl containing benzene ring and / or heterocyclic structure.

5. The solid electrolyte according to any one of claims 1 to 4, characterized in that, The solid electrolyte matrix includes a sulfide solid electrolyte.

6. The solid electrolyte according to claim 5, characterized in that, The sulfide solid electrolyte includes a sulfide-germanium ore-type electrolyte Li. n PS m X, where n is 5 to 7, m is 4 to 6, and X includes at least one of Cl, Br, and I.

7. The solid electrolyte according to any one of claims 1 to 6, characterized in that, The coating agent comprises at least one of undecyl mercaptan, dodecyl mercaptan, dodecyl sulfide, dodecyl methyl sulfide, bis(dodecyl disulfide), tetradecyl mercaptan, hexadecyl sulfide, di(octadecyl) disulfide, docosyl mercaptan, dodecyl trimethoxysilane, octadecyl trimethoxysilane, dodecyl phosphate, bis(2-ethylhexyl) phosphate, and C8-C18 perfluoroalkyl phosphate, preferably including at least one of undecyl mercaptan, dodecyl mercaptan, dodecyl sulfide, dodecyl methyl sulfide, bis(dodecyl disulfide), tetradecyl mercaptan, hexadecyl sulfide, di(octadecyl) disulfide, and docosyl mercaptan.

8. The solid electrolyte according to any one of claims 1 to 7, characterized in that, The heteroatom groups are adsorbed on the surface of the solid electrolyte host, and the molecular chains of the coating agent are arranged radially along the solid electrolyte host.

9. The solid electrolyte according to any one of claims 1 to 8, characterized in that, The mass ratio of the coating layer to the mass of the solid electrolyte body is 0.0001 to 0.

1.

10. A method for preparing a solid electrolyte according to any one of claims 1 to 9, characterized in that, include: The solid electrolyte substrate and the coating agent are stirred and mixed, so that the coating agent is adsorbed onto the surface of the solid electrolyte substrate to obtain the solid electrolyte.

11. The method according to claim 10, characterized in that, include: The solid electrolyte matrix, the coating agent, and the dispersant are stirred and mixed to obtain a first mixture; The dispersant is removed from the first mixture to obtain the solid electrolyte.

12. The method according to claim 11, characterized in that, The step of stirring and mixing the solid electrolyte bulk, coating agent and dispersant includes: The coating agent and the dispersant are stirred and mixed to obtain a second mixture; The second mixture is mixed with the solid electrolyte matrix and stirred at 40°C to 120°C to obtain the first mixture.

13. The method according to claim 11 or 12, characterized in that, The ratio of the solid electrolyte matrix, the coating agent, and the dispersant is 100g: 0.01-10g: 400-600ml.

14. The method according to any one of claims 11 to 13, characterized in that, The dispersant includes at least one of toluene, o-xylene, m-xylene, p-xylene, benzene, mesitylene, n-heptane, n-hexane, n-octane, n-nonane, n-decane, cyclohexane, cyclopentane, methylcyclohexane, ethylcyclohexane, dimethylbenzene, dimethylformamide, and dimethyl sulfoxide.

15. The method according to any one of claims 11 to 14, characterized in that, The moisture content of the dispersant is not greater than 100 ppm, preferably not greater than 20 ppm.

16. The method according to any one of claims 11 to 15, characterized in that, The dispersant in the first mixture is removed by vacuum evaporation.

17. The method according to any one of claims 11 to 16, characterized in that, Also includes: After removing the dispersant from the first mixture, the product after removing the dispersant is dried to obtain the solid electrolyte.

18. A battery, characterized in that, The solid electrolyte includes any one of claims 1 to 9.

19. A battery assembly, characterized in that, Includes the solid electrolyte of any one of claims 1 to 9 or the battery of claim 18.

20. An electrical device, characterized in that, It includes the solid electrolyte of any one of claims 1 to 9, the battery of claim 18, or the battery assembly of claim 19.

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