Solid-state battery and preparation method thereof, positive electrode sheet, and electric device

Abstract

This application relates to a solid-state battery and its preparation method, a positive electrode sheet, and an electrical device. The solid-state battery includes a positive electrode layer, which includes a positive electrode active material layer. The positive electrode active material layer includes lithium nickel cobalt manganese oxide material, a sulfide-based solid electrolyte, and an additive containing halogens. By introducing a halogen-containing additive into the positive electrode active material layer, the additive can decompose to generate halogen free radicals. Since the halogen free radicals can react with the oxygen released by the lithium nickel cobalt manganese oxide material at high temperatures, oxygen is anchored, thereby preventing the reaction between oxygen and the sulfide-based solid electrolyte. This suppresses the exothermic reaction between the lithium nickel cobalt manganese oxide material and the sulfide-based solid electrolyte, avoiding the release of a large amount of heat and improving the safety of the solid-state battery.

Description

Technical Field

[0001] This application relates to the field of solid-state battery technology, and further to solid-state batteries and their preparation methods, positive electrode sheets, and electrical devices. Background Technology

[0002] Solid-state batteries use a non-flammable solid electrolyte instead of the organic electrolyte in traditional liquid secondary batteries, significantly improving battery safety and are considered the next generation of batteries closest to industrialization. However, in solid-state batteries, safety decreases when fully charged. Summary of the Invention

[0003] In view of the above problems, this application provides a solid-state battery, a method for its fabrication, a positive electrode, and an electrical device thereof. This solid-state battery exhibits high safety.

[0004] The first aspect of this application provides a solid-state battery, including a positive electrode layer, the positive electrode layer including a positive electrode active material layer, the positive electrode active material layer including lithium nickel cobalt manganese oxide material, a sulfide solid electrolyte and an additive, the additive containing halogen.

[0005] In its fully charged state, lithium nickel cobalt manganese oxide (LiCO) undergoes a phase transition at high temperatures, releasing oxygen. This oxygen reacts with sulfide-based solid electrolytes to produce various byproducts, including sulfur dioxide, and releases a significant amount of heat. Therefore, by introducing halogen-containing additives into the positive electrode active material layer, these additives decompose at high temperatures to generate halogen free radicals. Since these halogen free radicals can react with the oxygen released by the LiCO material at high temperatures, they effectively anchor the oxygen, preventing further reaction between the oxygen and the sulfide-based solid electrolyte. This suppresses the exothermic reaction between the LiCO material and the sulfide-based solid electrolyte, avoiding the release of large amounts of heat and improving the safety of solid-state batteries.

[0006] In any embodiment of this application, the additive comprises one or more of F, Cl, Br and I.

[0007] In any embodiment of this application, the additive includes one or more of LiF, LiCl, LiBr, and LiI.

[0008] In any embodiment of this application, the mass of the additive accounts for 1%-15% of the total mass of the additive and the sulfide solid electrolyte.

[0009] In any embodiment of this application, the mass of the additive accounts for 5%-10% of the total mass of the additive and the sulfide solid electrolyte.

[0010] In any embodiment of this application, the Dv50 of the additive is less than or equal to twice the Dv50 of the sulfide-based solid electrolyte.

[0011] In any embodiment of this application, the Dv50 of the additive is less than or equal to the Dv50 of the lithium nickel cobalt manganese oxide material.

[0012] In any embodiment of this application, the Dv50 of the additive is 0.05μm-1μm.

[0013] In any embodiment of this application, the additive is lithium bromide, and the sulfide solid electrolyte is a sulforaphane-germanium ore type electrolyte. In the X-ray diffraction pattern of the mixture of lithium bromide, the sulforaphane-germanium ore type electrolyte, and the lithium nickel cobalt manganese oxide material, the intensity of the peak of lithium bromide appearing at the position of 2θ = 31.5~33.5° is denoted as I. A The intensity of the peak appearing at the position of 2θ = 29~31° in the sulfide-germanium mineral-type electrolyte is denoted as I. B The intensity of the peak appearing at the position of 2θ = 37~38° in the lithium nickel cobalt manganese oxide material is denoted as I. C Satisfying: I A / I B For 0.3-1, I A / I C It is 0.1-2.

[0014] In any embodiment of this application, the chemical formula of the lithium nickel cobalt manganese oxide material is LiNi. 1-x-y Co x Mn y O2, where 0 <x<0.4,0<y<0.4。

[0015] In any embodiment of this application, the Dv50 of the lithium nickel cobalt manganese oxide material is 0.5μm-15μm.

[0016] In any embodiment of this application, the sulfide-based solid electrolyte includes a sulforaphane-germanium ore type electrolyte, the chemical formula of which is Li. 7-a PS 6-a X a Where 0≤a<6, and X includes one or more of F, Cl, Br and I.

[0017] In any embodiment of this application, the Dv50 of the sulfide solid electrolyte is 0.3 μm-5 μm.

[0018] In any embodiment of this application, the solid-state battery is an all-solid-state battery.

[0019] A second aspect of this application provides a method for preparing a solid-state battery, the method comprising the step of preparing a composite cathode material, the method for preparing the composite cathode material comprising:

[0020] A composite cathode material is prepared by mixing additives with a sulfide-based solid electrolyte and then adding lithium nickel cobalt manganese oxide material; wherein the additives contain halogens.

[0021] In any embodiment of this application, the mixing method is ball milling, which may be wet ball milling.

[0022] In any embodiment of this application, the ball milling mixing speed is 150rpm-400rpm and the time is 0.5h-5h.

[0023] A third aspect of this application provides a positive electrode sheet, the positive electrode sheet comprising a positive active material layer, the positive active material layer comprising lithium nickel cobalt manganese oxide material, a sulfide solid electrolyte and additives, the additives comprising halogens.

[0024] In any embodiment of this application, the positive electrode is the positive electrode layer in the solid-state battery of the first aspect of this application.

[0025] The fourth aspect of this application provides an electrical device, including at least one of the solid-state battery of the first aspect of this application and the solid-state battery prepared by the preparation method of the solid-state battery of the second aspect of this application.

[0026] Details of one or more embodiments or examples of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0027] To better describe and illustrate the implementation methods, embodiments, or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described implementation methods, embodiments, or examples, or the best mode of conduct of these applications as currently understood.

[0028] In the attached diagram:

[0029] Figure 1 The image shows the XRD pattern of the composite cathode material prepared in Example 1.

[0030] Figure 2 The images show the DSC spectra of the composite cathode materials prepared in Examples 1-2 and Comparative Example 1.

[0031] Figure 3 This is a schematic diagram of a solid-state battery cell according to one embodiment of this application.

[0032] Figure 4 for Figure 3 An exploded view of a solid-state battery cell according to an embodiment of this application is shown.

[0033] Figure 5 This is a schematic diagram of a battery device according to one embodiment of this application.

[0034] Figure 6 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0035] Figure 7 for Figure 6 An exploded view of a battery pack according to one embodiment of this application is shown.

[0036] Figure 8 This is a schematic diagram of an electrical device that uses a solid-state battery as a power source according to one embodiment of this application.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Battery pack; 2. Upper casing; 3. Lower casing; 4. Battery assembly; 5. Solid-state battery cell; 51. Housing; 52. Solid-state battery cell; 53. Cover plate; 6. Electrical device. Detailed Implementation

[0039] The following describes in detail, with appropriate reference to the accompanying drawings, some embodiments of the solid-state battery and its fabrication method, positive electrode layer, and power application device of this application. However, some unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0040] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be included or excluded independently and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when describing a parameter as an integer ≥ 2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 for that parameter. For instance, when describing a parameter as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0041] In this application, unless otherwise specified, "about" means within a reasonable range above and below the stated number, and the range of fluctuation may vary depending on the type and value of the stated number. For example, a range of ±10%, ±5%, ±2%, ±1% is permissible. For instance, taking "about 20°C" as an example, where the approximation is ±1°C, approximate values ​​such as 19°C and 19.5°C within the approximation range indicated by "about 20°C" should also be included in the range indicated by "about 20°C".

[0042] In this application, the terms "multiple," "various," "multiple items," "several," etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more (greater than or equal to) two. It can be understood that when "any number of" items are involved, it refers to any suitable combination of multiple items, that is, a combination of "any number of" items in a manner that does not conflict and enables the implementation of this application.

[0043] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0045] Those skilled in the art will understand that the order in which the steps are written in the methods of various implementations or embodiments does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, and are preferably performed sequentially. For example, method M includes steps (1) and (2), indicating that the method may include steps (1) and (2) performed sequentially, or may include steps (1) and (2) performed sequentially. For example, method M may also include step (3), indicating that step (3) may be added to method M in any order. For example, method M may include steps (1), (2) and (3), or may include steps (1), (3) and (2), or may include steps (3), (1) and (2), etc.

[0046] In this application, unless otherwise specified, M (e.g., m1) means that m1 is a non-limiting example of M, and it is understood that M is not limited to m1.

[0047] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. Any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "M and / or N" represents the group consisting of M, N, and "a combination of M and N". "Containing M and / or N" can mean "containing M, containing N, and containing both M and N", or "containing M, containing N, or containing both M and N", and can be appropriately understood according to the context.

[0048] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0049] In this document, the term "suitable" in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the technical solution that enables the implementation of this application.

[0050] In this application, terms such as "further," "even more," "especially," "for example," "as," "example," and "exemplary" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0051] In this application, the terms "first aspect," "second aspect," "third aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0052] In this application, the exemplary descriptions such as "in some implementations (or embodiments)" and "in one implementation (or embodiment)" may cover, but are not limited to, the following meanings: these solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0053] In solid-state batteries, when fully charged, the positive electrode active material undergoes a phase transition at high temperatures, releasing oxygen. This oxygen reacts with the sulfide-based solid electrolyte to produce sulfur dioxide, releasing a large amount of heat and thus reducing the safety of the solid-state battery.

[0054] In view of this, this application introduces halogens into the positive electrode layer to anchor the oxygen released during the phase transition of the positive electrode active material, thereby preventing the reaction between oxygen and sulfide-based solid electrolytes, avoiding the release of a large amount of heat, and thus improving the safety of solid-state batteries.

[0055] Unless otherwise specified, the term "solid-state battery" in this application refers to a battery in which the electrolyte includes a solid electrolyte. Typically, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. During charging and discharging, active ions repeatedly insert and extract between the positive and negative electrode layers. The solid electrolyte layer acts as a conductor of ions between the positive and negative electrode layers and also isolates them, preventing short circuits. Therefore, a separator, as found in traditional lithium-ion batteries, is not required in solid-state batteries. Solid-state batteries use a non-flammable solid electrolyte instead of the organic electrolyte in traditional liquid lithium-ion batteries, significantly improving battery safety. In addition to enhanced safety, solid-state batteries are better suited for high-energy-density positive and negative electrode materials and reduce system weight, thus facilitating improvements in energy density.

[0056] In this application, unless otherwise specified, "solid electrolyte" refers to an electrolyte material or substance that exists in solid form during the storage and fabrication of solid-state batteries and their components, as well as during the operation of solid-state batteries. This includes, but is not limited to, solid electrolytes existing in solid form at room temperature.

[0057] In this application, unless otherwise specified, "electrode layer" includes electrode active material. The electrode layer can be a positive electrode layer or a negative electrode layer. "Electrode active material" in the electrode layer refers to a material capable of reversibly inserting and extracting active ions. Unless otherwise specified, "negative electrode active material" refers to a material used in the negative electrode layer capable of reversibly inserting and extracting active ions; "positive electrode active material" refers to a material used in the positive electrode layer capable of reversibly extracting and inserting active ions. During solid-state battery charging, active ions are extracted from the positive electrode, pass through the solid electrolyte layer, and insert into the negative electrode; while during solid-state battery discharging, active ions are extracted from the negative electrode and insert into the positive electrode. The active ions are not particularly limited or restrictive; they can be lithium ions, corresponding to a lithium-ion solid-state battery.

[0058] One or more embodiments of this application provide a solid-state battery, including a positive electrode layer, the positive electrode layer including a positive electrode active material layer, the positive electrode active material layer including lithium nickel cobalt manganese oxide material, a sulfide solid electrolyte and additives, the additives including halogens.

[0059] It should be noted that the additives can decompose to produce halogen free radicals, which can anchor the oxygen released by the positive electrode active material at high temperatures when it is fully charged.

[0060] The sulfide-based solid electrolyte contained in the positive electrode active material layer can enhance the ion conductivity of the positive electrode layer and reduce the interfacial impedance, thereby promoting the charge transfer efficiency between the positive electrode active material and the external environment and the full release of its capacity.

[0061] Understandably, by introducing halogen-containing additives into the positive electrode active material layer, the additives can decompose at high temperatures to produce halogen free radicals. Since the halogen free radicals can react with the oxygen released by the lithium nickel cobalt manganese oxide material at high temperatures, the oxygen is anchored, thereby preventing further reactions between oxygen and sulfide-based solid electrolytes. In other words, the exothermic reaction between lithium nickel cobalt manganese oxide material and sulfide-based solid electrolytes is suppressed, avoiding the release of a large amount of heat and improving the safety of solid-state batteries.

[0062] As an example, the components contained in the positive electrode active material layer can be determined using an X-ray diffractometer (XRD). The specific testing process is as follows: disassemble the solid-state battery, use a scraper to scrape off the positive electrode active material layer material on the positive electrode side, obtain the positive electrode active material layer powder, and then use XRD to test the composition.

[0063] In some embodiments, the additive contains one or more of F, Cl, Br, and I. This facilitates the anchoring of oxygen released from lithium nickel cobalt manganese oxide materials at high temperatures, avoids reactions between oxygen and sulfide-based solid electrolytes, and improves the safety of solid-state batteries.

[0064] As a non-limiting example, the additives include one or more of LiF, LiCl, LiBr, and LiI.

[0065] In some embodiments, the mass of the additive accounts for 0.5%-20% of the total mass of the additive and the sulfide solid electrolyte.

[0066] In some embodiments, the mass percentage of the additive to the total mass of the additive and the sulfide-based solid electrolyte is 1%-15%; for example, it can be, but is not limited to, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, or any range between two of the above values. When the amount of additive is within the above range, the heat generation of the positive electrode active material and the sulfide-based solid electrolyte in the fully charged state can be significantly reduced, and the impact on the battery charge-discharge performance is small.

[0067] In an optional embodiment, the mass of the additive accounts for 5%-10% of the total mass of the additive and the sulfide solid electrolyte.

[0068] As an example, the percentage of the mass of additives in the positive electrode active material layer mentioned in the context, relative to the total mass of additives and sulfide-based solid electrolytes, can be determined using the TG thermogravimetric method. The specific testing procedure is as follows: disassemble the solid-state battery, use a scraper to remove the positive electrode active material layer material from the positive electrode side, obtain the positive electrode active material layer powder, and then perform component analysis using TG.

[0069] In some implementations, the Dv50 of the additive is less than or equal to twice the Dv50 of the sulfide solid electrolyte.

[0070] As one possible implementation, the Dv50 of the additive is less than or equal to the Dv50 of the lithium nickel cobalt manganese oxide material.

[0071] When the additive's Dv50 meets the above characteristics, it has little impact on the conduction of ions and electrons during the charging and discharging process on the positive electrode side.

[0072] In some implementations, the additive has a Dv50 of 0.03 μm to 1.3 μm.

[0073] As one possible embodiment, the additive's Dv50 is 0.05 μm-1 μm; for example, it can be, but is not limited to, 0.05 μm, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, 0.5 μm, 0.55 μm, 0.6 μm, 0.65 μm, 0.7 μm, 0.75 μm, 0.8 μm, 0.85 μm, 0.9 μm, 0.95 μm, 1 μm, or any range between two of the above Dv50 values. When the additive's Dv50 is within the above range, it has a relatively small impact on the conduction of ions and electrons during the charging and discharging process on the positive electrode side.

[0074] It should be noted that the Dv50 of the additive mentioned above refers to the particle size corresponding to 50% of the additive's volume distribution. As an example, Dv50 can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, according to GB / T 19077-2016, Particle Size Distribution by Laser Diffraction. The specific testing procedure is as follows:

[0075] Pretreatment: Take a clean beaker, add an appropriate amount of the sample to be tested, add a surfactant and then add a dispersant, and sonicate at 120W for 5 minutes to ensure that the sample is completely dispersed in the dispersant.

[0076] Test: After the sample is poured into the injection tower, it circulates with the solution to the test optical path system. Under the irradiation of the laser beam, the particle size distribution characteristics can be obtained by receiving and measuring the energy distribution of the scattered light (shading degree: 8%-12%).

[0077] As one possible embodiment, the additive is lithium bromide, and the sulfide solid electrolyte is a sulforaphane-germanium ore type electrolyte. In the X-ray diffraction pattern of the mixture of lithium bromide, sulforaphane-germanium ore type electrolyte, and lithium nickel cobalt manganese oxide material, the intensity of the peak of lithium bromide appearing at the position of 2θ = 31.5~33.5° is denoted as I. A The intensity of the peak appearing at 2θ = 29~31° in the sulfide-germanium type electrolyte is denoted as I. B The intensity of the peak appearing at the position of 2θ = 37~38° in lithium nickel cobalt manganese oxide material is denoted as I. C Satisfying: I A / I B For 0.3-1, I A / I C The value is 0.1-2. This helps to anchor the oxygen released by lithium nickel cobalt manganese oxide materials at high temperatures, thus improving the safety of solid-state batteries.

[0078] As an example, I A / I B It can be, but is not limited to, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1 or the range between any two of the above ratios, etc. I A / I C It can be, but is not limited to, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range between any two of the above ratios, etc.

[0079] In some embodiments, the chemical formula of the lithium nickel cobalt manganese oxide material is LiNi 1-x-y Co x Mn y O2, where 0 < x < 0.4 and 0 < y < 0.4. As a possible embodiment, the Dv50 of the lithium nickel cobalt manganese oxide material is 0.5 μm - 15 μm; for example, it can be, but is not limited to, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm or the range between any two Dv50 values, etc. When the Dv50 of the lithium nickel cobalt manganese oxide material is within the above range, the prepared solid-state battery has excellent battery performance.

[0080] It should be noted that the Dv50 of the lithium nickel cobalt manganese oxide material mentioned above refers to the particle size corresponding to 50% in the volume distribution of the lithium nickel cobalt manganese oxide material. As an example, Dv50 can be conveniently measured by a laser particle size analyzer according to GB / T 19077-2016 Laser diffraction method for particle size distribution, such as the Mastersizer2000E laser particle size analyzer of Malvern Instruments Limited, UK. The specific test process can be:

[0081] Pretreatment: Take a clean beaker, add an appropriate amount of the sample to be tested, add a surfactant dropwise and then add a dispersant, and ultrasonicate at 120 W for 5 min to ensure that the sample is completely dispersed in the dispersant.

[0082] Testing: After the sample is poured into the injection tower, it circulates with the solution to the test optical path system. When the particles are irradiated by the laser beam, the particle size distribution characteristics (light obscuration: 8% - 12%) can be obtained by receiving and measuring the energy distribution of the scattered light.

[0083] In some embodiments, the sulfide-based solid electrolyte includes the argyrodite-type electrolyte, and the chemical formula of the argyrodite-type electrolyte is Li 7-a PS 6-a X aWhere 0≤a<6, and X includes one or more of F, Cl, Br and I.

[0084] In some embodiments, the Dv50 of the sulfide-based solid electrolyte is 0.3 μm-5 μm; for example, it can be, but is not limited to, 0.3 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or any range between two of the above Dv50 values. When the Dv50 of the sulfide-based solid electrolyte is within the above range, it exhibits higher lithium-ion conductivity and density.

[0085] It should be noted that the Dv50 of the sulfide solid electrolyte mentioned above refers to the particle size corresponding to 50% of the volume distribution of the sulfide solid electrolyte. As an example, Dv50 can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, according to GB / T 19077-2016, Particle Size Distribution by Laser Diffraction. The specific testing procedure is as follows:

[0086] Pretreatment: Take a clean beaker, add an appropriate amount of the sample to be tested, add a surfactant and then add a dispersant, and sonicate at 120W for 5 minutes to ensure that the sample is completely dispersed in the dispersant.

[0087] Test: After the sample is poured into the injection tower, it circulates with the solution to the test optical path system. Under the irradiation of the laser beam, the particle size distribution characteristics can be obtained by receiving and measuring the energy distribution of the scattered light (shading degree: 8%-12%).

[0088] As one possible implementation method, the solid-state battery is an all-solid-state battery.

[0089] In this application, unless otherwise specified, "all-solid-state battery" refers to a solid-state battery in which all electrolytes are solid electrolytes. In this case, the positive electrode layer, negative electrode layer and electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery, so it can be called "all-solid-state battery".

[0090] A solid-state battery includes at least one solid-state battery cell. A solid-state battery may include one or more solid-state battery cells.

[0091] In this application, unless otherwise specified, "solid-state battery cell" refers to a basic unit capable of converting chemical energy into electrical energy, and all its components are solid-state. In some embodiments, a solid-state battery cell may be an all-solid-state battery cell.

[0092] In this application, unless otherwise specified, "all-solid-state battery cell" refers to a solid-state battery cell in which all electrolytes are solid electrolytes. In this case, the positive electrode layer, negative electrode layer and electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery cell, so it can be called "all-solid-state battery cell".

[0093] In some implementations, a solid-state battery cell includes a solid-state battery cell.

[0094] In some implementations, the solid-state cell is an all-solid-state cell.

[0095] In some embodiments, a solid-state battery cell (which may be an all-solid-state battery cell) includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0096] The positive electrode layer can be prepared using either a dry or wet method. For example, it can be prepared by dry pressing. Alternatively, it can be prepared by wet coating and drying.

[0097] Unless otherwise stated, the positive electrode layer in this application includes at least a positive electrode active material layer.

[0098] Non-limiting, the weight percentage of positive electrode active particles or positive electrode active material in the positive electrode active material layer can be ≥70wt%, further ≥80wt%, even further ≥90wt%, and can also be 70wt% ~ 99wt%, optionally 80wt% ~ 95wt%.

[0099] In some embodiments, the positive electrode active material layer includes a conductive agent (which may be referred to as a positive electrode conductive agent). As a non-limiting example, the positive electrode conductive agent may be a carbon conductive agent. Non-limitingly, the carbon conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the positive electrode conductive agent may include, but is not limited to, one or more of SP, KS-6, acetylene black, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs), and graphene. Non-limitingly, the weight percentage of the positive electrode conductive agent in the positive electrode active material layer may be 0-10 wt%, more further 0-8 wt%, even further 0-5 wt%, and even further 0.1 wt%-3 wt%. When the positive electrode material is prepared into a positive electrode active material layer using a dry method, the positive electrode conductive agent can be incorporated into the positive electrode material, which can improve the conductivity of the positive electrode active material layer.

[0100] In some embodiments, the positive electrode layer can be prepared by: dry mixing the components used to prepare the positive electrode layer, such as positive electrode active material particles, positive electrode electrolyte particles, positive electrode conductive agent, additives, and any other components; then heating and pressurizing the mixed material to form a clump; and applying this clump to one side of the solid electrolyte layer for hot rolling to form the positive electrode layer. Non-limitingly, a dual planetary mixer can be used for dry mixing. Non-limitingly, a kneading mixer can be used for heated and pressurized kneading. Non-limitingly, the temperature for hot rolling can be 75°C to 85°C, and further, such as 78°C, 80°C, 82°C, etc.

[0101] The negative electrode layer can be prepared by dry or wet methods. For example, it can be formed by dry pressing. Alternatively, it can be formed by wet coating.

[0102] In this application, unless otherwise specified, the negative electrode layer includes at least a negative electrode active material layer.

[0103] Without limitation, the negative electrode active material layer may include a solid electrolyte. The solid electrolyte in the negative electrode active material layer may be referred to as "negative electrode electrolyte particles".

[0104] In this application, unless otherwise specified, "negative electrode electrolyte particles" refers to solid electrolytes that can be used in the negative electrode layer. Negative electrode electrolyte particles can enhance the ion conductivity of the negative electrode layer, reduce interfacial impedance, and promote the charge transfer efficiency and full release of the capacity of the negative electrode active material with the external environment.

[0105] In this application, unless otherwise specified, "negative electrode active particles" refers to particles containing negative electrode active substances that have the ability to reversibly insert and extract active ions.

[0106] In some embodiments, the negative electrode layer includes a negative electrode active material layer, which includes negative electrode active particles containing negative electrode active material.

[0107] Without limitation, the weight percentage of negative electrode active particles or negative electrode active materials in the negative electrode active material layer can be ≥70wt%, and more preferably ≥80wt%.

[0108] Non-limitingly, the weight percentage of the negative electrode electrolyte particles in the negative electrode active material layer can be 0 to 30 wt%, preferably 0.1 wt% to 30 wt%, and further preferably 5 wt% to 20 wt%.

[0109] In some embodiments, the negative electrode active particles or negative electrode active material are lithium indium alloys (InLi alloys).

[0110] In some implementations, the negative electrode layer is an InLi alloy film.

[0111] In some embodiments, the negative electrode active material may also be a negative electrode active material known in the art for use in solid-state batteries. As a non-limiting example, the negative electrode active material may include one or more of the following materials: elemental silicon, elemental tin, silicon-carbon composites, silicon suboxide, graphite, and metallic lithium. However, this application is not limited to these materials or substances, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0112] In some embodiments, the negative electrode layer may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer comprising a negative electrode active material. As a non-limiting example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0113] 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. In the negative electrode current collector, the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. In the negative electrode current collector, the composite current collector may be formed by forming a metal material on the polymer material substrate. Non-limiting examples of the metal material in the negative electrode current collector may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limiting examples of the polymer material substrate in the negative electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0114] In some embodiments, the negative electrode active material layer optionally includes a conductive agent (which may be referred to as a negative electrode conductive agent). Non-limitingly, the negative electrode conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. Non-limitingly, the weight percentage of the negative electrode conductive agent in the negative electrode active material layer may be 0-15 wt%, more preferably 0-10 wt%, and even more preferably 0-5 wt%.

[0115] In some embodiments, the negative electrode active material layer optionally includes a binder (denoted as negative electrode binder). As a non-limiting example, the negative electrode binder may include one or more 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). Non-limitingly, the weight percentage of the negative electrode binder in the negative electrode active material layer may be 0 to 10 wt%, more further 0 to 5 wt%, even more further 1 wt% to 5 wt%, and even more preferably 1 wt% to 3 wt%.

[0116] In some embodiments, the negative electrode active material layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)). The weight percentage of other additives in the negative electrode active material layer may be 0-15 wt%, more preferably 0-10 wt%, even more preferably 0-5 wt%, even more preferably 0-3 wt%, and even more preferably 0-2 wt%.

[0117] In some embodiments, the negative electrode layer can be prepared by dispersing the components used to prepare the negative electrode layer, such as negative electrode active particles, negative electrode electrolyte particles, negative electrode conductive agent, negative electrode binder, and any other components, in a solvent to form a negative electrode slurry. Further, the negative electrode slurry is coated onto at least one surface of the negative electrode current collector, and after drying, cold pressing, and other processes, the negative electrode layer is obtained. Cold pressing can be performed using a cold rolling mill. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 30wt% to 70wt%, optionally 40wt% to 60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000 mPa·s to 10000 mPa·s, optionally 3000 mPa·s to 10000 mPa·s. When coating the negative electrode slurry, the coating density per unit area (after deducting solvent) can be 1.5 mg / cm³, based on the amount coated on one side of the negative electrode current collector and on a dry weight basis. 2 ~ 22 mg / cm 2 However, this is not the only possibility. The compaction density of the negative electrode sheet can be 1.0 g / cm³. 3 ~ 2.0 g / cm 3 1.0 g / cm³ is an optional value. 3 ~ 1.8 g / cm 3 .

[0118] A solid electrolyte layer can be introduced by forming electrode layers on both sides of the solid electrolyte membrane, or it can be introduced on the electrode layer.

[0119] The solid electrolyte layer acts as a conductor of ions between the positive and negative electrode layers, and can also isolate the positive and negative electrode layers to prevent short circuits between them.

[0120] It is understood that the solid electrolyte layer includes a solid electrolyte. The solid electrolyte in the solid electrolyte layer can be a solid electrolyte known in the art that can be used in solid-state batteries.

[0121] The types of solid electrolytes present in different film layers of a solid-state battery can be the same or different. For example, the solid electrolytes in the positive electrode layer and the solid electrolyte layer can be the same or different.

[0122] As a non-limiting example, in different film layers of a solid-state battery, the solid electrolyte may include one or more of the following: sulfide solid electrolyte, halide solid electrolyte, oxide solid electrolyte, polymer solid electrolyte, etc.

[0123] As another non-limiting example, in different film layers of a solid-state battery, the solid electrolyte can be, but is not limited to, one or more of oxide-based solid electrolytes, sulfide-based solid electrolytes, and halide-based solid electrolytes. In some embodiments, the solid electrolyte can independently include, but is not limited to, one or more of Argyrodite-type sulfide electrolytes and halide electrolytes. Non-limiting examples of oxide-based solid electrolytes may include LISICON-type oxide electrolytes (such as γ-Li3PO4), NASICON-type oxide electrolytes (such as Li... 1+x Al x Ge 2-x (PO4)3,Li 1+x Al x Ti 2-x (PO4)3, etc., 0≤x≤1), Garnet type (such as Li7La3Zr2O12, etc.), perovskite type oxide electrolytes (such as Li 3x La 2 / 3-x One or more of the following: TiO3, etc. (0≤x≤0.5). Non-limiting examples of sulfide solid electrolytes may include Li. 10 GeP2S 12 Li₂S-P₂S₅, Argyrodite type (such as Li₆PS₅Cl, Li 5.5 PS 5.5 Cl 1.5One or more of the following (etc.). Non-limiting examples of halide solid electrolytes may include one or more of the following: Li3InCl6, Li3YCl6, Li3ScCl6, Li3ErCl6, Li2ZrCl6, etc.

[0124] The solid electrolyte layer can be prepared using a dry process. In some embodiments, the solid electrolyte layer can be formed by pressing a solid electrolyte material into a solid electrolyte membrane. In other embodiments, the solid electrolyte layer is formed by pressing the constituent materials of the solid electrolyte layer onto an electrode layer.

[0125] In this application, the sheet-like solid electrolyte layer may also be referred to as a solid electrolyte membrane.

[0126] As a non-limiting example, the solid electrolyte layer can also be prepared by a wet process, wherein the electrolyte slurry used includes at least a solid electrolyte and an organic solvent, and typically also includes one or more of a binder and a dispersant.

[0127] In some embodiments, the thickness of the solid electrolyte layer can be 0.1 μm-1000 μm, and can be selected as 10 μm-100 μm, 100 μm-800 μm, 500 μm-800 μm, etc.

[0128] In some embodiments, the solid-state battery may include an outer packaging. This outer packaging can be used to encapsulate the aforementioned solid-state battery cell.

[0129] In some embodiments, the outer packaging of a solid-state battery can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of a solid-state battery can also be a soft pack, such as a pouch-type soft pack. The material of the soft pack can be plastic; further, non-limiting examples of plastics may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0130] This application does not impose any particular limitation on the shape of the solid-state battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 3 This is an example of a square-structured solid-state battery cell 5.

[0131] In some of these implementations, reference is made to... Figure 4 The outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 can be placed over the opening to close the receiving cavity. A solid-state battery cell 52 is encapsulated within the receiving cavity. The number of solid-state battery cells 52 contained in a single solid-state battery cell 5 may be one or more, which can be selected by those skilled in the art according to actual needs.

[0132] Solid-state batteries can be battery device 4 or battery pack 1.

[0133] The battery device includes at least one solid-state battery cell. The number of solid-state battery cells in the battery device can be one or more, and those skilled in the art can select an appropriate number according to the application and capacity of the battery device.

[0134] Figure 5 This is battery device 4, used as an example. (See reference...) Figure 5 In the battery device 4, multiple solid-state battery cells 5 can be arranged sequentially along the length of the battery device 4. Of course, they can also be arranged in any other manner. Furthermore, the multiple solid-state battery cells 5 can be fixed in place using fasteners.

[0135] Optionally, the battery device 4 may also include a housing with a receiving space in which a plurality of solid-state battery cells 5 are housed.

[0136] In some embodiments, the battery devices described above can also be assembled into a battery pack, and the number of battery devices contained in the battery pack can be one or more. Those skilled in the art can select an appropriate number according to the application and capacity of the battery pack.

[0137] Figure 6 and Figure 7 This is battery pack 1 as an example. (See reference...) Figure 6 and Figure 7 The battery pack 1 may include a battery box and multiple battery devices 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery devices 4. The multiple battery devices 4 can be arranged in any manner within the battery box.

[0138] One or more embodiments of this application provide a method for preparing a solid-state battery. The method includes the step of preparing a composite cathode material. The method for preparing the composite cathode material includes: mixing an additive with a sulfide-based solid electrolyte, and then adding lithium nickel cobalt manganese oxide material to prepare the composite cathode material; wherein the additive contains halogen.

[0139] In some implementations, the mixing method is ball milling.

[0140] In some alternative implementations, the mixture is mixed using wet ball milling.

[0141] As one possible embodiment, the solvent used in wet ball milling includes n-heptane.

[0142] As a non-limiting example, pressing is performed using a rolling process. The rolling process can be cold pressing or hot rolling. A non-limiting example of a temperature for hot rolling is 180°C.

[0143] In some embodiments, the ball milling speed is 150 rpm to 400 rpm; for example, it can be, but is not limited to, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, or any range between two of the above speeds. When the ball milling speed is within the above range, it is beneficial to achieve uniform mixing and can avoid reducing the ionic conductivity of the sulfide-based solid electrolyte.

[0144] As one possible implementation, the ball milling mixing time is 0.5h-5h; for example, it can be, but is not limited to, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, or any range between any two of the above times.

[0145] In some optional embodiments, the composite cathode material further includes a conductive agent, and the preparation method of the composite cathode material includes: mixing the additive with a sulfide-based solid electrolyte, then adding lithium nickel cobalt manganese oxide material and a conductive agent to prepare the composite cathode material; wherein the additive contains halogen.

[0146] As a non-limiting example, the preparation method of a solid-state battery includes: step S1, adding additives and sulfide-based solid electrolytes into a ball mill jar, adding n-heptane for ball milling and mixing to obtain a mixture; mixing the mixture with lithium nickel cobalt manganese oxide material and optional conductive agent, and then grinding and mixing with a mortar to prepare a composite positive electrode material; wherein, the additives contain halogens, and the amount of n-heptane is sufficient to cover the grinding balls; step S2, pressing the solid electrolyte material into a solid electrolyte layer; step S3, after applying the composite positive electrode material to one side of the solid electrolyte layer, compacting the composite positive electrode material on the solid electrolyte layer; step S4, applying a negative electrode layer to the opposite side of the solid electrolyte layer to prepare a solid-state battery.

[0147] One or more embodiments of this application provide a positive electrode sheet, which includes a positive active material layer, comprising lithium nickel cobalt manganese oxide material, a sulfide solid electrolyte, and additives, wherein the additives contain halogens.

[0148] In some embodiments, the additive comprises one or more of F, Cl, Br and I.

[0149] In some embodiments, the additives include one or more of LiF, LiCl, LiBr, and LiI.

[0150] In some embodiments, the mass of the additive accounts for 0.5%-20% of the total mass of the additive and the sulfide solid electrolyte.

[0151] In some embodiments, the mass percentage of the additive to the total mass of the additive and the sulfide solid electrolyte is 1%-15%; for example, it can be, but is not limited to, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, or any range between any two of the above values.

[0152] In an optional embodiment, the mass of the additive accounts for 5%-10% of the total mass of the additive and the sulfide solid electrolyte.

[0153] In some implementations, the Dv50 of the additive is less than or equal to twice the Dv50 of the sulfide solid electrolyte.

[0154] In some embodiments, the Dv50 of the additive is less than or equal to the Dv50 of the lithium nickel cobalt manganese oxide material.

[0155] In some implementations, the additive has a Dv50 of 0.03 μm to 1.3 μm.

[0156] As one possible embodiment, the Dv50 of the additive is 0.05μm-1μm; for example, it can be, but is not limited to, 0.05μm, 0.1μm, 0.15μm, 0.2μm, 0.25μm, 0.3μm, 0.35μm, 0.4μm, 0.45μm, 0.5μm, 0.55μm, 0.6μm, 0.65μm, 0.7μm, 0.75μm, 0.8μm, 0.85μm, 0.9μm, 0.95μm, 1μm, or any range between any two of the above Dv50 values.

[0157] As one possible embodiment, the additive is lithium bromide, and the sulfide solid electrolyte is a sulfide-germanium sulfide type electrolyte. The intensity of the peak appearing at the position of 2θ = 31.5~33.5° in the X-ray diffraction pattern of lithium bromide is denoted as I. A The intensity of the peak appearing at 2θ = 29~31° in the X-ray diffraction pattern of the argyrocerite-type electrolyte is denoted as I. B The intensity of the peak appearing at the position of 2θ = 37~38° in the X-ray diffraction pattern of lithium nickel cobalt manganese oxide material is denoted as I. C Satisfying: I A / I B For 0.3-1, I A / I C It is 0.1-2.

[0158] In some embodiments, the chemical formula of the lithium nickel cobalt manganese oxide material is LiNi 1-x-y Co x Mn y O2, where 0 <x<0.4,0<y<0.4。

[0159] As one possible implementation, the Dv50 of the lithium nickel cobalt manganese oxide material is 0.5μm-15μm; for example, it can be, but is not limited to, 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, or any range between any two of the above Dv50.

[0160] In some embodiments, the sulfide solid electrolyte includes a sulforaphane-germanium ore type electrolyte, the chemical formula of which is Li. 7-a PS 6-a X a Where 0≤a<6, and X includes one or more of F, Cl, Br and I.

[0161] In some embodiments, the Dv50 of the sulfide solid electrolyte is 0.3 μm-5 μm; for example, it can be, but is not limited to, 0.3 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or any range between any two of the above Dv50.

[0162] One or more embodiments of this application provide an electrical device comprising at least one of the solid-state battery described above and a solid-state battery prepared by the method described above.

[0163] In some embodiments, the electrical device includes at least one of the solid-state batteries of any of the embodiments provided in this application.

[0164] In a non-limiting sense, solid-state batteries can be used as a power source for electrical devices or as an energy storage unit for electrical devices. Electrical devices can include, but are not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Mobile devices can be, for example, mobile phones, laptops, etc.; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric motorcycles, power tools, etc., but are not limited to these. This electrical device can also be applied to military equipment, aerospace, and other fields, and can also be applied to energy storage power systems such as hydroelectric, thermal, wind, and solar power plants.

[0165] As an electrical device, solid-state batteries can be selected based on its usage requirements.

[0166] Figure 8 Here is an example of an electrical device 6. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device for solid-state batteries, a battery device or battery pack can be used.

[0167] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a thin and light design and can use solid-state batteries as their power source.

[0168] The following describes some embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where the technology or conditions are not specified in the embodiments, they are performed according to the description above, or according to the technology or conditions described in the literature in the art, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially, or can be synthesized from commercially available products using conventional methods.

[0169] I. Solid-state battery fabrication

[0170] Example 1

[0171] Step S1: Place LiBr particles and sulfide solid electrolyte Li6PS5Cl in a ball mill jar at a mass ratio of 0.5:9.5, add n-heptane to cover the milling beads, and ball mill at 300 rpm for 1 hour; then mix 250 mg of the ball-milled mixture with 700 mg of lithium nickel cobalt manganese oxide material LiNi 0.83 Co 0.11 Mn 0.06 O2 and 50 mg of vapor-grown carbon fibers were ground and mixed uniformly in a mortar to obtain a composite cathode material. The Dv50 of the LiBr particles was 1 μm, the Dv50 of the sulfide solid electrolyte Li6PS5Cl was 0.5 μm, and the lithium nickel cobalt manganese oxide material LiNi... 0.83 Co 0.11 Mn 0.06 The Dv50 of O2 is 5 μm.

[0172] Step S2: Weigh 700mg In powder and 300mg Li6PS5Cl powder, grind and mix them evenly in a mortar and pestle to obtain composite In powder.

[0173] Step S3: Weigh 120 mg of Li6PS5Cl powder and press it into a complete electrolyte sheet under a pressure of 1 t to obtain a solid electrolyte layer;

[0174] Step S4: Spread 20mg of composite cathode material on one side surface of the solid electrolyte layer, and compact the composite cathode material on the solid electrolyte layer with a pressure of 3t to form a cathode layer;

[0175] Step S5: Laminate 100mg of composite In powder on the surface opposite to the solid electrolyte layer, and place a copper-lithium sheet on top to form a negative electrode layer, thus obtaining a solid-state battery.

[0176] Example 2

[0177] The preparation methods of Example 2 and Example 1 are similar, except that in Example 2, when preparing the composite cathode material, the mass ratio of LiBr particles to sulfide solid electrolyte Li6PS5Cl is 1:9, and all other aspects are the same.

[0178] Example 3

[0179] The preparation methods of Example 3 and Example 1 are similar, except that in Example 3, when preparing the composite cathode material, the mass ratio of LiBr particles to sulfide solid electrolyte Li6PS5Cl is 1.5:8.5, and all other aspects are the same.

[0180] Example 4

[0181] The preparation methods of Example 4 and Example 1 are similar, except that in Example 4, when preparing the composite cathode material, the mass ratio of LiBr particles to sulfide solid electrolyte Li6PS5Cl is 0.1:9.9, and all other aspects are the same.

[0182] Example 5

[0183] The preparation methods of Example 5 and Example 1 are similar, except that in Example 5, when preparing the composite cathode material, the mass ratio of LiBr particles to sulfide solid electrolyte Li6PS5Cl is 0.05:9.95, and all other aspects are the same.

[0184] Example 6

[0185] The preparation methods of Example 6 and Example 1 are similar, except that in Example 6, when preparing the composite cathode material, the mass ratio of LiBr particles to sulfide solid electrolyte Li6PS5Cl is 2:8, and all other aspects are the same.

[0186] Example 7

[0187] The preparation methods of Example 7 and Example 1 are similar, except that: in Example 7, when preparing the composite cathode material, the Dv50 of the LiBr particles is 0.5 μm, the Dv50 of the sulfide solid electrolyte Li6PS5Cl is 0.5 μm, and the lithium nickel cobalt manganese oxide material LiNi 0.83 Co 0.11 Mn0.06 The Dv50 of O2 is 5 μm.

[0188] Example 8

[0189] The preparation methods of Example 8 and Example 1 are similar, except that in Example 8, when preparing the composite cathode material, the Dv50 of the LiBr particles is 0.05 μm, the Dv50 of the sulfide solid electrolyte Li6PS5Cl is 0.5 μm, and the lithium nickel cobalt manganese oxide material LiNi 0.83 Co 0.11 Mn 0.06 The Dv50 of O2 is 5 μm.

[0190] Example 9

[0191] The preparation methods of Example 9 and Example 1 are similar, except that in Example 9, when preparing the composite cathode material, the Dv50 of the LiBr particles is 0.03 μm, the Dv50 of the sulfide solid electrolyte Li6PS5Cl is 0.5 μm, and the lithium nickel cobalt manganese oxide material LiNi 0.83 Co 0.11 Mn 0.06 The Dv50 of O2 is 5 μm.

[0192] Example 10

[0193] The preparation methods of Example 10 and Example 1 are similar, except that: in Example 10, when preparing the composite cathode material, the Dv50 of the LiBr particles is 1.2 μm, the Dv50 of the sulfide solid electrolyte Li6PS5Cl is 0.6 μm, and the lithium nickel cobalt manganese oxide material LiNi 0.83 Co 0.11 Mn 0.06 The Dv50 of O2 is 5 μm.

[0194] Example 11

[0195] The preparation methods of Example 11 and Example 1 are similar, except that: in Example 11, when preparing the composite cathode material, the Dv50 of the LiBr particles is 1 μm, the Dv50 of the sulfide solid electrolyte Li6PS5Cl is 0.4 μm, and the lithium nickel cobalt manganese oxide material LiNi 0.83 Co 0.11 Mn 0.06 The Dv50 of O2 is 5 μm.

[0196] Example 12

[0197] The preparation methods of Example 12 and Example 1 are similar, except that: in Example 12, when preparing the composite cathode material, the Dv50 of the LiBr particles is 1 μm, the Dv50 of the sulfide solid electrolyte Li6PS5Cl is 0.5 μm, and the lithium nickel cobalt manganese oxide material LiNi 0.83 Co 0.11 Mn 0.06 The Dv50 of O2 is 0.8 μm.

[0198] Example 13

[0199] The preparation methods of Example 13 and Example 1 are similar, except that in Example 13, when preparing the composite cathode material, an equal mass of LiF is used to replace LiBr, while all other aspects are the same.

[0200] Example 14

[0201] The preparation methods of Example 14 and Example 1 are similar, except that in Example 14, when preparing the composite cathode material, an equal mass of LiCl was used instead of LiBr, while all other aspects are the same.

[0202] Example 15

[0203] The preparation methods of Example 15 and Example 1 are similar, except that in Example 15, when preparing the composite cathode material, an equal mass of LiI is used to replace LiBr, while all other aspects are the same.

[0204] Comparative Example 1

[0205] The preparation methods of Comparative Example 1 and Example 1 are similar, except that LiBr was not added when preparing the composite cathode material in Comparative Example 1, while everything else is the same.

[0206] Comparative Example 2

[0207] The preparation methods of Comparative Example 2 and Example 1 are similar, except that in Comparative Example 2, when preparing the composite cathode material, an equal mass of Al2O3 was used to replace LiBr, while all other aspects were the same.

[0208] The solid-state batteries prepared in the above embodiments and comparative examples were subjected to measurements of the following parameters: Dv50 of the additive, the percentage w of the mass of the additive to the total mass of the additive and the sulfide solid electrolyte, the particle size of the lithium nickel cobalt manganese oxide material, and the particle size of the sulfide solid electrolyte. The results are shown in Table 1.

[0209] Table 1

[0210]

[0211] In Table 1, Dv501 refers to the Dv50 of the additive in the positive electrode layer of the solid-state battery, Dv502 refers to the Dv50 of the sulfide solid electrolyte in the positive electrode layer of the solid-state battery, and Dv503 refers to the Dv50 of the lithium nickel cobalt manganese oxide material in the positive electrode layer of the solid-state battery.

[0212] The percentage w of the aforementioned additives in the total mass of the additives and sulfide solid electrolytes was determined by thermogravimetric analysis. The specific test procedure is as follows:

[0213] The solid-state battery was disassembled, and the positive electrode active material layer was scraped off using a scraper to obtain the positive electrode active material layer powder. The powder was then analyzed for composition using TG. The testing steps included: 1. Sample preparation: Weigh approximately 10 mg of sample into an Al2O3 crucible and level it. 2. Parameter settings: Oxygen atmosphere, purge gas 50 mL / min, protective gas 20 mL / min. 3. Temperature rise program: 10℃ / min, 35℃-800℃.

[0214] The Dv50 of the additives, sulfide solid electrolytes, and lithium nickel cobalt manganese oxide materials in the positive electrode layer of the solid-state battery mentioned above was determined using a Mastersizer 2000E laser particle size analyzer of Malvern Instruments Ltd., UK, according to the laser diffraction method for particle size distribution in GB / T 19077-2016.

[0215] II. Performance Testing

[0216] 1. The composite cathode material prepared in step S1 of Example 1 was determined by X-ray diffraction. The specific testing method was as follows: Sample preparation: A sample cell with a depth of 1 mm and a diameter of 25 mm was prepared according to the plate sample preparation method; Testing: Starting angle 10°, ending angle 80°, step size 0.01671°, step duration 0.24 s; Fixed core parameters: voltage: 40 kV, current: 40 mA, anti-scattering slit: 1 mm. The results are shown in Figure 1. Figure 1 It can be seen that the ratio of the intensity of the peak appearing at 2θ=31.5~33.5° of lithium bromide to the intensity of the peak appearing at 2θ=29~31° of the silver sulfide-germanium ore type electrolyte is 0.67; the ratio of the intensity of the peak appearing at 2θ=31.5~33.5° of lithium bromide to the intensity of the peak appearing at 2θ=37~38° of lithium nickel cobalt manganese oxide material is 0.75.

[0217] 2. The thermal stability of the composite cathode materials prepared in each embodiment and comparative example was tested using differential scanning calorimetry (DSC). Specifically, under an argon atmosphere, the temperature was increased from 35°C to 460°C at a rate of 10°C / min, and the total heat generation of the composite cathode material at high temperature was measured. The heat generation results of the composite cathode materials in each embodiment and comparative example are shown in Table 2. The DSC spectra of the composite cathode materials in Examples 1-2 and Comparative Example 1 are shown below. Figure 2 As shown.

[0218] 3. Capacity Testing: The solid-state batteries prepared in the above embodiments and comparative examples were placed in a constant temperature oven and charged and discharged using a Neware cell tester. First, the batteries were allowed to stand for 4 hours. Then, they were charged to 3.7V using a constant current of 0.33C, and then discharged to 1.9V. The specific capacity of the batteries during the first charge was then tested. The results are shown in Table 2.

[0219] 4. Cyclic Performance Test: The solid-state batteries prepared in the above embodiments and comparative examples were placed in a constant temperature oven and charged and discharged using a Neware cell tester. First, the batteries were allowed to stand for 4 hours, then charged to 3.7V using a constant current of 0.33C, and then discharged to 2V. This process was repeated to obtain the capacity retention rate after 100 cycles. The results are shown in Table 2.

[0220] Table 2

[0221]

[0222] As can be seen from the comparison of the results of Examples 1-15 and Comparative Examples 1-2 in Table 1, the composite cathode material of Examples 1-15 generates less heat compared with Comparative Examples 1-2; indicating that by introducing halogen-containing additives into the cathode layer of the solid-state battery, this application helps to suppress the exothermic reaction between lithium nickel cobalt manganese oxide material and sulfide solid electrolyte, thus avoiding the release of a large amount of heat.

[0223] A comparison of the results from Examples 1-4 and Examples 5-6 shows that by further controlling the percentage of additives in the total mass of additives and sulfide solid electrolytes to within the range of 1%-15%, it is beneficial to further suppress the exothermic reaction between lithium nickel cobalt manganese oxide materials and sulfide solid electrolytes, reduce heat release, and have a smaller impact on battery cycle performance.

[0224] A comparison of the results from Examples 1, 7-8, and 9-10 shows that adjusting the Dv50 of the additive within the range of 0.05μm-1μm is beneficial for further reducing heat release and has little impact on battery cycle performance.

[0225] A comparison of the results from Examples 1, 7-8, and 11-12 shows that by adjusting the Dv50 of the additive to be less than or equal to twice the Dv50 of the sulfide solid electrolyte, and by adjusting the Dv50 of the additive to be less than or equal to the Dv50 of the lithium nickel cobalt manganese oxide material, it is beneficial to further reduce heat release while having a smaller impact on battery cycle performance.

[0226] The descriptions of the various implementation methods and embodiments above tend to emphasize the differences between them. Similarities or resemblances can be referenced interchangeably, and for the sake of brevity, they will not be repeated here. The technical features of the implementation methods and embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combinations of these technical features do not contradict each other, they should be considered within the scope of this specification.

[0227] It should be noted that this application is not limited to the above-described embodiments and examples. The above-described embodiments and examples are merely examples, and any embodiments and examples that have the same structure and achieve the same effect as the technical concept within the scope of this application are included in the technical scope of this application. The embodiments and examples described above only illustrate several embodiments and examples of this application, and although the descriptions are relatively detailed, they should not be construed as limiting the scope of the patent. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments or examples, and other ways of constructing embodiments or examples by combining some of the constituent elements of the embodiments or examples, are also included in the scope of this application without departing from the spirit of this application.

Claims

1. A solid-state battery, characterized in that, It includes a positive electrode layer, which includes a positive electrode active material layer, which includes lithium nickel cobalt manganese oxide material, a sulfide solid electrolyte, and additives, wherein the additives contain halogens.

2. The solid-state battery as described in claim 1, characterized in that, The additive contains one or more of F, Cl, Br and I.

3. The solid-state battery as described in claim 1, characterized in that, The additives include one or more of LiF, LiCl, LiBr, and LiI.

4. The solid-state battery according to any one of claims 1 to 3, characterized in that, The mass percentage of the additive to the total mass of the additive and the sulfide solid electrolyte is 1%-15%.

5. The solid-state battery according to any one of claims 1 to 4, characterized in that, The mass percentage of the additive to the total mass of the additive and the sulfide solid electrolyte is 5%-10%.

6. The solid-state battery according to any one of claims 1 to 5, characterized in that, The Dv50 of the additive is less than or equal to twice the Dv50 of the sulfide-based solid electrolyte; and / or The Dv50 of the additive is less than or equal to the Dv50 of the lithium nickel cobalt manganese oxide material.

7. The solid-state battery according to any one of claims 1 to 6, characterized in that, The additive has a Dv50 of 0.05 μm-1 μm.

8. The solid-state battery according to any one of claims 1 to 7, characterized in that, The additive is lithium bromide, and the sulfide solid electrolyte is a sulforaphane-germanium ore type electrolyte. In the X-ray diffraction pattern of the mixture of lithium bromide, the sulforaphane-germanium ore type electrolyte, and the lithium nickel cobalt manganese oxide material, the intensity of the peak of lithium bromide appearing at the position of 2θ = 31.5~33.5° is denoted as I. A The intensity of the peak appearing at the position of 2θ = 29~31° in the sulfide-germanium mineral-type electrolyte is denoted as I. B The intensity of the peak appearing at the position of 2θ = 37~38° in the lithium nickel cobalt manganese oxide material is denoted as I. C Satisfying: I A / I B For 0.3-1, I A / I C It is 0.1-2.

9. The solid-state battery according to any one of claims 1 to 8, characterized in that, The chemical formula of the lithium nickel cobalt manganese oxide material is LiNi 1-x-y Co x Mn y O2, where 0 < x < 0.4, 0 < y < 0.4; and / or The Dv50 of the lithium nickel cobalt manganese oxide material is 0.5μm-15μm.

10. The solid-state battery according to any one of claims 1 to 9, characterized in that, The sulfide-based solid electrolytes include silver-germanium sulfide-type electrolytes, the chemical formula of which is Li. 7-a PS 6-a X a Where 0 ≤ a < 6, X includes one or more of F, Cl, Br and I; and / or The Dv50 of the sulfide-based solid electrolyte is 0.3 μm-5 μm.

11. The solid-state battery according to any one of claims 1 to 10, characterized in that, The solid-state battery is an all-solid-state battery.

12. A method for preparing a solid-state battery, characterized in that, The preparation method includes the step of preparing a composite cathode material, wherein the preparation method of the composite cathode material includes: A composite cathode material is prepared by mixing additives with a sulfide-based solid electrolyte and then adding lithium nickel cobalt manganese oxide material; wherein the additives contain halogens.

13. The preparation method according to claim 12, characterized in that, The mixing method is ball milling, which may be wet ball milling; and / or The ball milling mixing speed is 150rpm-400rpm, and the time is 0.5h-5h.

14. A positive electrode plate, characterized in that, The positive electrode includes a positive active material layer, which includes lithium nickel cobalt manganese oxide material, sulfide solid electrolyte and additives, wherein the additives contain halogens.

15. The positive electrode sheet as described in claim 14, characterized in that, The positive electrode in a solid-state battery as described in any one of claims 2 to 10.

16. An electrical appliance, characterized in that, It includes at least one of the solid-state batteries as described in any one of claims 1 to 11 and solid-state batteries prepared by the method of preparing solid-state batteries as described in any one of claims 12 to 13.

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