Solid-state battery, positive electrode sheet, positive electrode active material, preparation method, electric device and use

Abstract

A solid-state battery, a positive electrode sheet, a positive electrode active material, a preparation method, an electric device and the use. The solid-state battery comprises a positive electrode layer, wherein the positive electrode layer comprises a positive electrode active material layer, the positive electrode active material layer comprising a positive electrode active material and a sulfide electrolyte. The positive electrode active material comprises positive electrode composite coating particles, and the positive electrode composite coating particle comprises an inner core containing a lithium-rich manganese-based positive electrode material, a first coating layer coating at least part of the surface of the inner core and a second coating layer coating at least part of the surface of the first coating layer. The first coating layer comprises a first coating material, and the first coating material comprises a metal oxide having an electronic conductivity greater than or equal to 1 S / cm. The second coating layer comprises a second coating material, and the second coating material comprises a lithium-indium-based halide, wherein the atomic molar ratio of lithium to indium to a halogen in the lithium-indium-based halide is a: b: c, where 2≤a≤3, 0＜b≤1 and 4≤c≤6. The discharge capacity and cycle performance of the solid-state battery are effectively improved.

Description

Solid-state batteries, positive electrode sheets, positive electrode active materials, preparation methods, electrical devices and applications

[0001] This application claims priority to Chinese patent application filed on November 8, 2024, application number 202411595523.5, entitled "Solid-state battery, positive electrode sheet, positive electrode active material, preparation method, electrical device and application", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of solid-state battery technology, and in particular to a solid-state battery, a positive electrode sheet, a positive electrode active material, a preparation method, an electrical device, and an application. Background Technology

[0003] Solid-state batteries use non-flammable solid electrolytes instead of the organic electrolytes in traditional liquid solid-state batteries, significantly improving battery safety and are considered the next generation of batteries closest to industrialization. However, when lithium-rich manganese-based cathode materials are used in all-solid-state batteries, the capacity is relatively low and the cycle performance is poor. Summary of the Invention

[0004] This application provides a solid-state battery, a positive electrode sheet, a positive electrode active material, a preparation method, an electrical device, and an application. The solid-state battery has both high capacity utilization and good cycle performance.

[0005] To achieve the above objectives, a 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 comprising a positive electrode active material and a sulfide electrolyte, the positive electrode active material comprising positive electrode composite coated particles, the positive electrode composite coated particles comprising:

[0006] The core comprises a lithium-rich manganese-based cathode material;

[0007] A first coating layer covers at least a portion of the surface of the core, the first coating layer comprising a first coating material, the first coating material comprising a metal oxide with an electronic conductivity ≥1 S / cm; and

[0008] A second coating layer is applied to at least a portion of the surface of the first coating layer. The second coating layer comprises a second coating material, which includes a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium, and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, and 4≤c≤6.

[0009] Therefore, the positive electrode active material layer of the solid-state battery uses a core containing lithium-rich manganese-based positive electrode material and a composite coating layer including a first coating layer and a second coating layer. The first coating layer contains a metal oxide with high electronic conductivity (e.g., ≥1 S / cm), and the metal oxide exhibits good stability with both the lithium-rich manganese-based positive electrode material and the sulfide electrolyte. Using it as a coating layer can effectively improve the electronic conductivity of the positive electrode active material. Simultaneously, some metal elements in the metal oxide may also be doped into the crystal lattice of the lithium-rich manganese-based positive electrode material, improving its structural stability. The second coating layer contains a lithium indium-based halide with high ionic conductivity (e.g., >1 mS / cm), and using it as a coating layer can effectively improve the interfacial ion conduction of the positive electrode active material. Therefore, by forming a composite coating layer on the surface of lithium-rich manganese-based cathode materials, the electronic and ionic conductivity of the cathode active material can be significantly improved, thereby enhancing the utilization rate of anion redox reactions and increasing the discharge capacity of the cathode active material in solid-state batteries. Simultaneously, during charging, the lithium-rich manganese-based cathode material undergoes O2 oxidation. 2- To O2 2- The oxidation process further enhances the discharge capacity of the positive electrode active material in solid-state batteries. In O 2- To O2 2- During the oxidation process, O2 2- The oxygen can be stabilized by the In element in the second coating material, forming In-O bonds, thus preventing the release of oxygen from the lithium-rich manganese-based cathode material. During discharge, the In-O bonds can be reduced to In-Cl bonds, continuing to suppress oxygen release in subsequent charge-discharge cycles. Therefore, there is a coupling relationship between the oxygen ion redox in the lithium-rich manganese-based cathode material and the indium ion redox in the second coating material, which suppresses oxygen release and improves the cycle performance of the cathode active material. In summary, by forming a composite coating on the surface of the lithium-rich manganese-based cathode material, the electronic and ionic conductivity of the cathode active material can be improved, and oxygen release can be suppressed, thereby increasing the discharge capacity and cycle performance of the cathode active material. This, in turn, improves the discharge capacity and cycle performance of solid-state batteries using this cathode active material, and also benefits the first-efficiency and rate performance of solid-state batteries.

[0010] In some embodiments of this application, the general chemical formula of the lithium indium-based halide is Li. a In b Q x Cl c , 2≤a≤3, 0<b≤1, 0≤x<1, 0<b+x≤1, 4≤c≤6, Q includes at least one of Sc, Y and Zr.

[0011] In some embodiments, the general chemical formula of the lithium indium-based halide is Li₂In. b Sc 0.666-b Cl4, 0 < b ≤ 0.5.

[0012] In some embodiments, the general chemical formula of the lithium indium-based halide is Li3Y. 1–b In b Cl6, 0.5≤b≤1.

[0013] In some embodiments, the general chemical formula of the lithium indium-based halide is Li 2+b In b Zr 1-b Cl6, 0.5≤b<1.

[0014] In some embodiments of this application, the first coating material includes one or more of Li2RuO3, Fe3O4, Sb-doped SnO2, Sn-doped In2O3, and Al-doped ZnO.

[0015] In some embodiments of this application, the first covering material includes at least one of the following features (1)-(3):

[0016] (1) In Sb-doped SnO2, the total number of Sb and Sn atoms is used as the benchmark, and the atomic percentage of Sb is recorded as w1, where 0 < w1 ≤ 10 at%.

[0017] (2) In Sn-doped In2O3, the atomic percentage of Sn is recorded as w2, with the total number of Sn and In atoms as the benchmark, and 0 < w2 ≤ 20 at%.

[0018] (3) In Al-doped ZnO, the total number of Al and Zn atoms is used as the benchmark, and the percentage of Al atoms is denoted as w3, where 0 < w3 ≤ 10at%.

[0019] In some embodiments of this application, the first coating material covers at least a portion of the surface of the lithium-rich manganese-based material, and the second coating material covers at least a portion of the surface of the first coating material.

[0020] In some embodiments of this application, the first covering layer has at least one of the following features (1)-(2):

[0021] (1) The mass percentage of the first coating material contained in the first coating layer in the positive electrode composite coated particles is 0.1%-5%;

[0022] (2) The thickness of the first coating layer is 0.1nm-50nm.

[0023] In some embodiments of this application, the first covering layer has at least one of the following features (1)-(2):

[0024] (1) The mass percentage of the first coating material contained in the first coating layer in the positive electrode composite coated particles is 0.1%-3%;

[0025] (2) The thickness of the first coating layer is 0.1nm-10nm.

[0026] In some embodiments of this application, the second covering layer has at least one of the following features (1)-(2):

[0027] (1) The mass percentage of the second coating material contained in the second coating layer in the positive electrode composite coated particles is 0.1%-5%;

[0028] (2) The thickness of the second coating layer is 0.1nm-50nm.

[0029] In some embodiments of this application, the second covering layer has at least one of the following features (1)-(2):

[0030] (1) The mass percentage of the second coating material contained in the second coating layer in the positive electrode composite coated particles is 0.1%-3%;

[0031] (2) The thickness of the second coating layer is 0.1 nm-10 nm. In some embodiments of this application, the lithium-rich manganese-based cathode material is a layered lithium-rich manganese-based cathode material.

[0032] In some embodiments of this application, the general chemical formula of the lithium-rich manganese-based cathode material satisfies xLi2MnO3·(1-x)LiMO2, where M includes one or more elements selected from Ni, Co, Mn, Cr, Fe, Al, Nb, Zr, Mo, and Ta, and 0 < x < 1.

[0033] In some embodiments of this application, the Dv50 of the positive electrode composite coated particles is 0.01μm-20μm.

[0034] In some embodiments of this application, the Dv50 of the positive electrode composite coated particles is 0.5 μm-15 μm. This is beneficial for improving the discharge capacity of the positive electrode composite coated particles and maintaining good contact between the lithium-rich manganese-based positive electrode material and the sulfide electrolyte within the positive electrode composite coated particles.

[0035] In some embodiments of this application, the Dv50 of the positive electrode composite coated particles is 1μm-10μm.

[0036] In some embodiments of this application, the Dv50 of the sulfide electrolyte is 0.001 μm-20 μm.

[0037] In some embodiments of this application, the Dv50 of the sulfide electrolyte is ≤1 μm. This allows for better improvement of the interfacial contact between the cathode layer and the battery layer while maintaining the overall ion-conducting capability of the sulfide electrolyte, thereby enhancing the electrochemical performance of the battery and reducing manufacturing costs.

[0038] In some embodiments of this application, the Dv50 of the sulfide electrolyte is 0.05 μm-1 μm.

[0039] In some embodiments of this application, the sulfide electrolyte includes one or more of the following: silver-germanium sulfide type sulfide electrolyte, lithium-germanium-phosphorus-sulfide type sulfide electrolyte, and lithium-sulfide-phosphorus-pentasulfide complex type sulfide electrolyte.

[0040] In some embodiments of this application, the sulfide electrolyte includes at least one of the following features (1)-(3):

[0041] (1) The chemical formula of the silver-germanium sulfide electrolyte satisfies Li 6±s P 1-j A j S 5±s-t B t X 1±s , 0≤j<1, 0≤t<1, 0≤s<1, element A includes one or more elements from Ge, Si, Sn and Sb, element B includes one or more elements from O, Se and Te, and element X is selected from one or more elements from Cl, Br, I and F;

[0042] (2) The chemical formula of the lithium-germanium-phosphorus-sulfur electrolyte satisfies Li 10±δ Ge 1-g G g P 2-q Q q S 12-w W w , 0≤δ<1, 0≤g≤1, 0≤q≤2, 0≤w<1, G element includes one or more elements from Si and Sn, Q element includes Sb, W element is selected from one or more elements from O, Se, Te, Cl, Br, I and F;

[0043] (3) The chemical formula of the lithium sulfide pentaphosphide complex sulfide electrolyte satisfies (100-uv)Li2S·uP2S5·vM m N n, where 0 < u < 100, 0 ≤ v < 100, 0 ≤ u + v < 100, 0 ≤ m < 4, 0 ≤ n < 6, the M element is selected from one or more elements of Li, B, Ge, Si, Sn, and Sb, and the N element is selected from one or more elements of S, Se, Te, O, Cl, Br, I, and F.

[0044] In some embodiments of the present application, the solid-state battery has at least one of the following characteristics (1)-(2):

[0045] (1) The mass ratio of the positive electrode active material in the positive electrode active material layer is 50%-99%;

[0046] (2) The mass ratio of the sulfide electrolyte in the positive electrode active material layer is 0.1%-50%.

[0047] In some embodiments of the present application, the solid-state battery has at least one of the following characteristics (1)-(2):

[0048] (1) The mass ratio of the positive electrode active material in the positive electrode active material layer is 70%-95%;

[0049] (2) The mass ratio of the sulfide electrolyte in the positive electrode active material layer is 5%-30%.

[0050] In some embodiments of the present application, the solid-state battery is a lithium-ion all-solid-state battery.

[0051] The second aspect of the present application provides a positive electrode sheet, including a positive electrode active material layer, the positive electrode active material layer contains a positive electrode active material and a sulfide electrolyte, the positive electrode active material includes positive electrode composite coated particles, and the positive electrode composite coated particles include:

[0052] A core, the core contains a lithium-rich manganese-based positive electrode material;

[0053] A first coating layer, coated on at least part of the surface of the core, the first coating layer contains a first coating material, and the electronic conductivity of the first coating material ≥ 1 S / cm; and

[0054] A second coating layer, coated on at least part of the surface of the first coating layer, the second coating layer contains a second coating material, the second coating material includes a lithium indium-based halide, wherein the atomic molar ratio of lithium element, indium element, and halogen in the lithium indium-based halide is a:b:c, 2 ≤ a ≤ 3, 0 < b ≤ 1, 4 ≤ c ≤ 6.

[0055] In some embodiments of the present application, the positive electrode sheet is the positive electrode layer in the solid-state battery of the first aspect of the present application.

[0056] A third aspect of this application provides a positive electrode active material, the positive electrode active material comprising positive electrode composite coated particles, the positive electrode composite coated particles comprising:

[0057] The core comprises a lithium-rich manganese-based cathode material;

[0058] A first coating layer covers at least a portion of the surface of the core, the first coating layer comprising a first coating material having an electronic conductivity ≥ 1 S / cm; and

[0059] A second coating layer is applied to at least a portion of the surface of the first coating layer. The second coating layer comprises a second coating material, which includes a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium, and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, and 4≤c≤6.

[0060] In some embodiments of this application, the positive electrode active material is the positive electrode active material in the solid-state battery of the first aspect of this application.

[0061] The fourth aspect of this application provides a method for preparing a positive electrode active material, the positive electrode active material comprising positive electrode composite coated particles, the method for preparing the positive electrode active material comprising preparing the positive electrode composite coated particles, the preparation of the positive electrode composite coated particles comprising:

[0062] An intermediate is prepared by subjecting a mixed powder containing a core of lithium-rich manganese-based cathode material and a first coating agent to a first heat treatment to form a first coating layer on at least a portion of the surface of the core.

[0063] The mixture comprising the intermediate and the second coating agent is subjected to a second heat treatment to form a second coating layer on at least a portion of the surface of the intermediate;

[0064] The first coating agent comprises a metal oxide with an electronic conductivity ≥1 S / cm; the second coating agent comprises a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, 4≤c≤6.

[0065] The fifth aspect of this application provides an electrical device, including a solid-state battery according to the first aspect of this application.

[0066] The power supply device of this application includes the solid-state battery provided in this application, and therefore has at least the same advantages as the solid-state battery.

[0067] The sixth aspect of this application provides the use of the solid-state battery of the first aspect of this application, the positive electrode of the second aspect of this application, or the positive active material of the third aspect of this application in supplying and / or storing electrical energy, said application including at least one process of charging and discharging at a voltage of 4.5V or higher.

[0068] Details of one or more embodiments 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

[0069] To better describe and illustrate the 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 embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0070] Figure 1 is a schematic diagram of a solid-state battery cell according to an embodiment of this application.

[0071] Figure 2 is an exploded view of a solid-state battery cell according to an embodiment of this application shown in Figure 1.

[0072] Figure 3 is a schematic diagram of a battery device according to an embodiment of this application.

[0073] Figure 4 is a schematic diagram of a battery pack according to one embodiment of this application.

[0074] Figure 5 is an exploded view of the battery pack of one embodiment of this application shown in Figure 4.

[0075] Figure 6 is a schematic diagram of an electrical device using a solid-state battery as a power source according to an embodiment of this application.

[0076] Explanation of reference numerals in the attached drawings: 1 Battery pack; 2 Upper casing; 3 Lower casing; 4 Battery assembly; 5 Solid-state battery cell; 51 Casing; 52 Solid-state battery cell; 53 Cover plate; 6 Electrical device. Detailed Implementation

[0077] The following describes in detail, with appropriate reference to the accompanying drawings, some embodiments of the solid-state battery, positive electrode sheet, positive electrode active material, preparation method, electrical device, and application 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.

[0078] 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 independently included or excluded, and they can be combined arbitrarily, meaning 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.

[0079] 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.

[0080] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0081] 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.

[0082] Those skilled in the art will understand that the order in which the steps are written in the methods of various embodiments or examples 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, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0083] In this application, open-ended technical features or solutions described using terms such as "containing," "comprising," or "including" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both the feature or solution that "A consists of a1, a2, and a3" and the feature or solution that "A includes not only a1, a2, and a3, but also other members." In this application, unless otherwise specified, A (e.g., a1) indicates that a1 is a non-limiting example of A, and it can be understood that A is not limited to a1.

[0084] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. Unless otherwise specified, the descriptions such as "optionally include" and "optionally contain" in this application, taking "optionally include" as an example, mean "may include or not include."

[0085] 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, "X and / or Y" means the group consisting of X, Y, and "a combination of X and Y". "Containing X and / or Y" can mean "containing X, containing Y, and containing X and Y", or "containing X, containing Y, or containing X and Y", and can be appropriately understood according to the context.

[0086] 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.

[0087] 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.

[0088] Lithium-rich manganese-based cathode materials are promising next-generation rechargeable battery cathode materials due to their high specific capacity (e.g., >280 mAh / g), high energy density (e.g., >1000 Wh / kg), low cost, and good thermal stability. Applying lithium-rich manganese-based cathode materials to sulfide all-solid-state batteries holds the promise of simultaneously achieving high energy density and high safety. However, in practical applications, lithium-rich manganese-based cathode materials exhibit low discharge capacity (e.g., <100 mAh / g), far below their theoretical capacity. Furthermore, their practical application in sulfide all-solid-state batteries also suffers from poor cycle performance. Therefore, when lithium-rich manganese-based cathode materials are used in all-solid-state batteries, the resulting batteries have low capacity and poor cycle performance. Uncoated lithium-rich manganese-based cathode materials exhibit very low capacity utilization and virtually no anion redox reaction. The electronic conductivity and ionic conductivity of lithium-rich manganese-based cathode materials are both above 10. -9 S / cm-10 -7Within the range of S / cm, it can be inferred that the capacity utilization of lithium-rich manganese-based cathode materials in solid-state batteries is closely related to their electronic and ionic conductivity. However, in related technologies, when using oxides such as Li3BO3 and Li2ZrO3 for coating, the low electronic and ionic conductivity of these oxides prevents the full utilization of the inherent capacity of the lithium-rich manganese-based cathode material. Therefore, this application employs a composite coating method for lithium-rich manganese-based cathode materials, simultaneously improving the electronic and ionic conductivity of the cathode active material and suppressing oxygen release from the lithium-rich manganese-based material, thereby enhancing the discharge capacity and cycle performance of the cathode active material, and ultimately improving the discharge capacity and cycle performance of solid-state batteries using this cathode active material.

[0089] 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.

[0090] 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.

[0091] 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 substance capable of reversibly inserting and extracting active ions. Unless otherwise specified, "negative electrode active material" refers to a substance used in the negative electrode layer capable of reversibly inserting and extracting active ions; "positive electrode active material" refers to a substance 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.

[0092] In this application, unless otherwise specified, "electrode active material layer" includes at least one of the positive electrode active material layer in the positive electrode layer and the negative electrode active material layer in the negative electrode layer. Depending on the specific circumstances, the electrode active material layer may refer to either the positive electrode active material layer or the negative electrode active material layer. It is understood that the positive electrode active material layer contains positive electrode active material, and the negative electrode active material layer contains negative electrode active material.

[0093] 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 comprising a positive electrode active material and a sulfide electrolyte, the positive electrode active material including positive electrode composite coated particles, the positive electrode composite coated particles including a core containing a lithium-rich manganese-based positive electrode material, a first coating layer coated on at least a portion of the surface of the core, and a second coating layer coated on at least a portion of the surface of the first coating layer; the first coating layer includes a first coating material, the first coating material including a metal oxide with an electronic conductivity ≥1 S / cm, the second coating layer includes a second coating material, the second coating material including a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, 4≤c≤6.

[0094] It should be noted that the terms "first coating layer," "second coating layer," "first coating material," and "second coating material" mentioned in the context are 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," etc., serve only as a non-exhaustive enumeration and should be understood as not constituting a closed limitation on quantity.

[0095] In this application, the term "lithium-rich manganese-based cathode material" refers to a solid solution composed of two materials, Li2MnO3 and LiMO2, where M is a transition metal element such as Ni, Co, or Mn.

[0096] As an example, the structure of the aforementioned positive electrode composite coated particles and the composition of the core, first coating layer and second coating layer can be determined by the following method: First, a positive electrode sheet is removed from the solid-state battery cell, and then the single positive electrode particle is cut and thinned by FIB (Focused Ion Beam) to obtain a TEM (Transmission Electron Microscopy) sample. Then, the crystal structure and elemental distribution of the core and coating layer are analyzed by TEM and EDS to obtain the composition information of the core, first coating layer and second coating layer.

[0097] Understandably, the positive electrode active material layer of the solid-state battery in this application comprises a core containing a lithium-rich manganese-based positive electrode material and a composite coating layer including a first coating layer and a second coating layer. The coating material in the first coating layer includes a metal oxide with high electronic conductivity (e.g., ≥1 S / cm), and the metal oxide exhibits good stability with both the lithium-rich manganese-based positive electrode material and the sulfide electrolyte. Using it as a coating layer can effectively improve the electronic conductivity of the positive electrode active material. Simultaneously, some metal elements in the metal oxide may also be doped into the crystal lattice of the lithium-rich manganese-based positive electrode material, improving the structural stability of the lithium-rich manganese-based positive electrode material. The second coating layer contains a second coating material containing lithium indium-based halides with high ionic conductivity (e.g., >1 mS / cm). Using it as a coating layer can effectively improve the interfacial ion conduction of the positive electrode active material. Therefore, by forming a composite coating layer on the surface of lithium-rich manganese-based cathode materials, the electronic and ionic conductivity of the cathode active material can be significantly improved, thereby enhancing the utilization rate of anion redox reactions and increasing the discharge capacity of the cathode active material in solid-state batteries. Simultaneously, during charging, the lithium-rich manganese-based cathode material undergoes O2 oxidation. 2- To O2 2- The oxidation process further enhances the discharge capacity of the positive electrode active material in solid-state batteries. In O 2- To O2 2- During the oxidation process, O2 2- The oxygen can be stabilized by the In element in the second coating material, forming In-O bonds, thus preventing the release of oxygen from the lithium-rich manganese-based cathode material. During discharge, the In-O bonds can be reduced to In-Cl bonds, continuing to suppress oxygen release in subsequent charge-discharge cycles. Therefore, there is a coupling relationship between the oxygen ion redox in the lithium-rich manganese-based cathode material and the indium ion redox in the second coating material, which suppresses oxygen release and improves the cycle performance of the cathode active material. In summary, by forming a composite coating on the surface of the lithium-rich manganese-based cathode material, the electronic and ionic conductivity of the cathode active material can be improved, and oxygen release can be suppressed, thereby increasing the discharge capacity and cycle performance of the cathode active material, and ultimately improving the discharge capacity and cycle performance of solid-state batteries using this cathode active material.

[0098] It is easy to understand that the technical solution of this application does not exclude the possibility that at least one of the core, the first coating layer, and the second coating layer includes other materials.

[0099] It should be noted that the core, the first coating layer, and the second coating layer may each independently include other materials, but their content should not make them the main components, so as to avoid affecting the composite coating of the lithium-rich manganese-based cathode material by the first coating material and the second coating material.

[0100] In some implementations, the core mainly includes or contains only lithium-rich manganese-based cathode material, the first coating layer mainly includes or contains only the first coating material, and the second coating layer mainly includes or contains only the second coating material.

[0101] In some embodiments, the first coating material of the first coating layer is directly coated on at least a portion of the surface of the lithium-rich manganese-based cathode material, and the second coating material is directly coated on at least a portion of the surface of the first coating material.

[0102] In some embodiments, the general chemical formula of the lithium indium-based halide is Li a In b Q x Cl c , 2≤a≤3, 0<b≤1, 0≤x<1, 0<b+x≤1, 4≤c≤6, Q includes at least one of Sc, Y and Zr.

[0103] In some embodiments, the general chemical formula of the lithium indium-based halide is Li₂In. b Sc 0.666-b Cl4, 0 < b ≤ 0.5.

[0104] In some embodiments, the general chemical formula of the lithium indium-based halide is Li3Y. 1–b In b Cl6, 0.5≤b≤1.

[0105] In some embodiments, the general chemical formula of the lithium indium-based halide is Li 2+b In b Zr 1-b Cl6, 0.5≤b<1.

[0106] In some embodiments, the first coating material includes one or more of Li2RuO3, Fe3O4, Sb-doped SnO2, Sn-doped In2O3, and Al-doped ZnO.

[0107] As one possible implementation, in Sb-doped SnO2, the atomic percentage of Sb is denoted as w1, based on the total number of Sb and Sn atoms, where 0 < w1 ≤ 10 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 1.5 at%, 2 at%, 2.5 at%, 3 at%, 3.5 at%, 4 at%, 4.5 at%, 5 at%, 5.5 at%, 6 at%, 6.5 at%, 7 at%, 7.5 at%, 8 at%, 8.5 at%, 9 at%, 9.5 at%, 10 at%, or any range between any two of the above values. In Sb-doped SnO2, when the atomic percentage of Sb is within the range mentioned above, based on the total number of Sb and Sn atoms, the resulting Sb-doped SnO2 (i.e., ATO) has a high electronic conductivity.

[0108] In some alternative embodiments, in Sn-doped In₂O₃, the atomic percentage of Sn is denoted as w₂, based on the total number of Sn and In atoms, where 0 < w₂ ≤ 20 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 2 at%, 3 at%, 4 at%, 5 at%, 6 at%, 7 at%, 8 at%, 9 at%, 10 at%, 11 at%, 12 at%, 13 at%, 14 at%, 15 at%, 16 at%, 17 at%, 18 at%, 19 at%, 20 at%, or any range between any two of the above values. In Sn-doped In₂O₃, when the atomic percentage of Sn is within the above range, based on the total number of Sn and In atoms, the obtained Sn-doped In₂O₃ (i.e., ITO) has a high electronic conductivity.

[0109] In some embodiments, in Al-doped ZnO, the atomic percentage of Al is denoted as w3, based on the total number of Al and Zn atoms, where 0 < w3 ≤ 10 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 1.5 at%, 2 at%, 2.5 at%, 3 at%, 3.5 at%, 4 at%, 4.5 at%, 5 at%, 5.5 at%, 6 at%, 6.5 at%, 7 at%, 7.5 at%, 8 at%, 8.5 at%, 9 at%, 9.5 at%, 10 at%, or any range between any two of the above values. In Al-doped ZnO, when the total number of Al and Zn atoms is within the above range, the resulting Al-doped ZnO (i.e., AZO) has a high electronic conductivity.

[0110] It should be noted that "at%" in the context refers to the percentage of atoms.

[0111] As an example, the atomic percentage of Sb in Sb-doped SnO2, the atomic percentage of Sn in Sn-doped In2O3, and the atomic percentage of Al in Al-doped ZnO mentioned in the context can be determined by the following method: Take a positive electrode sheet from the obtained solid-state battery cell, and then wash away the sulfide electrolyte in the positive electrode sheet by ethanol to obtain positive electrode powder. Then, the contents of trace elements such as Sb, Sn, In, Al, and Zn are obtained by ICP (inductively coupled plasma atomic emission spectrometry). The percentage of doped elements in the first coating layer can be calculated.

[0112] In some exemplary embodiments, the mass percentage of the first coating material contained in the first coating layer in the positive electrode composite coated particles is 0.1%-5%; for example, it can be, but is not limited to, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, or any range between any two of the above values. When the mass percentage of the first coating material in the positive electrode composite coated particles is within the above range, the first coating material has a suitable thickness, which can significantly improve the electronic conductivity of the lithium-rich manganese-based positive electrode material, thereby improving the capacity of the lithium-rich manganese-based positive electrode material.

[0113] In some optional embodiments, the first coating material contained in the first coating layer accounts for 0.1%-3% of the mass of the positive electrode composite coated particles.

[0114] In some embodiments, the second coating material contained in the second coating layer accounts for 0.1%-5% of the mass percentage of the cathode composite coated particles; for example, it can be, but is not limited to, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, or any range between two of the above values. When the mass percentage of the second coating material in the cathode composite coated particles is within the above range, the second coating layer has a suitable thickness, which can significantly improve the ionic conductivity of the lithium-rich manganese-based cathode material, thereby increasing the capacity of the lithium-rich manganese-based cathode material.

[0115] In one possible implementation, the second coating material contained in the second coating layer accounts for 0.1%-3% of the mass of the positive electrode composite coated particles.

[0116] As an example, the mass percentages of the first coating material and the second coating material in the positive electrode composite coated particles mentioned in the context can be obtained by testing as follows: Take a positive electrode sheet from the obtained solid-state battery cell, then wash away the sulfide electrolyte in the positive electrode sheet by ethanol to obtain positive electrode powder, and then test the contents of the main elements Ni, Co, Mn and coating elements Ru, In, etc. by ICP (inductively coupled plasma atomic emission spectrometry). The percentages of coating material content in the first coating layer and the second coating layer can be calculated.

[0117] In some embodiments, the thickness of the first coating layer is 0.1 nm to 50 nm; for example, it can be, but is not limited to, 0.1 nm, 0.5 nm, 1 nm, 3 nm, 5 nm, 8 nm, 10 nm, 13 nm, 15 nm, 18 nm, 20 nm, 23 nm, 25 nm, 28 nm, 30 nm, 33 nm, 35 nm, 38 nm, 40 nm, 43 nm, 45 nm, 48 nm, 50 nm, or any range between two of the above thicknesses. When the thickness of the first coating layer is within the above range, the electronic conductivity of the lithium-rich manganese-based cathode material can be significantly improved, thereby increasing the capacity of the lithium-rich manganese-based cathode material.

[0118] In some alternative implementations, the thickness of the first coating layer is 0.1 nm to 10 nm.

[0119] In some embodiments, the thickness of the second coating layer is 0.1 nm to 50 nm; for example, it can be, but is not limited to, 0.1 nm, 0.5 nm, 1 nm, 3 nm, 5 nm, 8 nm, 10 nm, 13 nm, 15 nm, 18 nm, 20 nm, 23 nm, 25 nm, 28 nm, 30 nm, 33 nm, 35 nm, 38 nm, 40 nm, 43 nm, 45 nm, 48 nm, 50 nm, or any range between two of the above thicknesses. When the thickness of the second coating layer is within the above range, the ionic conductivity of the lithium-rich manganese-based cathode material can be significantly improved, thereby increasing the capacity of the lithium-rich manganese-based cathode material.

[0120] In some exemplary embodiments, the thickness of the second coating layer is 0.1 nm to 10 nm.

[0121] As an example, the thickness of the first coating layer and the thickness of the second coating layer mentioned in the context can be determined by the following method: First, a positive electrode sheet is removed from the solid-state battery cell, and then the individual positive electrode particles are cut and thinned by FIB (Focused Ion Beam) to obtain a TEM (Transmission Electron Microscopy) sample. Then, the thickness of the first coating layer and the thickness of the second coating layer can be obtained by imaging analysis by TEM.

[0122] In some embodiments, the lithium-rich manganese-based cathode material is a layered lithium-rich manganese-based cathode material.

[0123] In some embodiments, the general chemical formula of the lithium-rich manganese-based cathode material satisfies xLi2MnO3·(1-x)LiMO2, where the M element includes one or more elements selected from Ni, Co, Mn, Cr, Fe, Al, Nb, Zr, Mo and Ta, and 0 < x < 1.

[0124] In some embodiments, the Dv50 of the positive electrode composite coated particles is 0.01 μm-20 μm; for example, it can be, but is not limited to, 0.01 μm, 0.05 μm, 0.1 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, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, etc. 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, 20μm, or any range between two of the above particle sizes.

[0125] In some optional embodiments, the Dv50 of the positive electrode composite coated particles is 0.5μm-15μm; for example, it can be, but is not limited to, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, or any range between two of the above particle sizes. When the Dv50 of the positive electrode composite coated particles is within the above range, it is beneficial to improve the discharge capacity of the positive electrode composite coated particles and maintain good contact between the lithium-rich manganese-based positive electrode material and the sulfide electrolyte within the positive electrode composite coated particles.

[0126] In some alternative implementations, the Dv50 of the positive electrode composite coated particles is 1 μm-10 μm.

[0127] As one possible implementation, the Dv50 of the sulfide electrolyte is 0.001 μm-20 μm; for example, it can be, but is not limited to, 0.001 μm, 0.005 μm, 0.01 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 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, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, or any range between two of the above particle sizes.

[0128] In some alternative embodiments, the Dv50 of the sulfide electrolyte is ≤1 μm. Therefore, by controlling the Dv50 of the sulfide electrolyte within the above range, it is beneficial to improve the interfacial contact between the cathode layer and the battery layer while taking into account the overall ion conduction capability of the sulfide electrolyte, thereby improving the electrochemical performance of the battery and also taking into account manufacturing costs.

[0129] In some alternative embodiments, the Dv50 of the sulfide electrolyte is 0.05 μm-1 μm.

[0130] It should be noted that Dv50 mentioned in the context refers to the particle size corresponding to 50% of the 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 Laser Diffraction Method. Specifically: Take an appropriate amount of the sample to be tested (the sample concentration should be 8%-12% (w / v) with a light-blocking degree), add 20 mL of solvent (deionized water is used for positive electrode materials, and p-xylene is used for sulfide electrolyte materials), and simultaneously overheat for 5 minutes (53 kHz / 120 W) to ensure complete sample dispersion. Then, determine the sample according to the GB / T19077-2016 / ISO 13320:2009 standard.

[0131] In some embodiments, the sulfide electrolyte includes one or more of the following: silver sulfide-germanium sulfide electrolyte, lithium germanium phosphorus sulfide electrolyte, and lithium sulfide pentaphosphate sulfide complex electrolyte.

[0132] As one possible implementation, the chemical formula of the silver-germanium sulfide electrolyte satisfies Li 6±s P 1-j A j S 5±s-t B t X 1±s , 0≤j<1, 0≤t<1, 0≤s<1, element A includes one or more of Ge, Si, Sn and Sb, element B includes one or more of O, Se and Te, and element X is selected from one or more of Cl, Br, I and F.

[0133] In some alternative embodiments, the chemical formula of the lithium-germanium-phosphorus-sulfur sulfide electrolyte satisfies Li 10±δ Ge 1-g G g P 2-q Q q S 12-w W w , 0≤δ<1, 0≤g≤1, 0≤q≤2, 0≤w<1, G element includes one or more elements from Si and Sn, Q element includes Sb, and W element is selected from one or more elements from O, Se, Te, Cl, Br, I and F.

[0134] In some of these embodiments, the chemical formula of the lithium pentasulfide-phosphorus disulfide complex-like sulfide electrolyte satisfies (100-uv)Li₂S·uP₂S₅·vM m N n, where 0 < u < 100, 0 ≤ v < 100, 0 ≤ u + v < 100, 0 ≤ m < 4, 0 ≤ n < 6, the M element is selected from one or more elements of Li, B, Ge, Si, Sn, and Sb, and the N element is selected from one or more elements of S, Se, Te, O, Cl, Br, I, and F.

[0135] In some optional embodiments, the mass percentage of the positive electrode active material in the positive electrode active material layer is 50% - 99%; for example, it can be but is not limited to 50%, 53%, 55%, 58%, 60%, 63%, 65%, 68%, 70%, 73%, 75%, 78%, 80%, 83%, 85%, 88%, 90%, 93%, 95%, 97%, 99% or the range between any two of the above values, etc. When the mass percentage of the positive electrode active material in the positive electrode active material layer is within the above range, it is beneficial to the good contact of the positive electrode active material, electrolyte, and conductive agent in the positive electrode active material layer, thereby enabling the high-capacity performance of the lithium-rich manganese-based positive electrode material.

[0136] As a possible embodiment, the mass percentage of the positive electrode active material in the positive electrode active material layer is 70% - 95%.

[0137] In some exemplary embodiments, the mass percentage of the sulfide electrolyte in the positive electrode active material layer is 0.1% - 50%; for example, it can be but is not limited to 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 23%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 43%, 45%, 48%, 50% or the range between any two of the above values, etc. When the mass percentage of the sulfide electrolyte in the positive electrode active material layer is within the above range, it is beneficial for the positive electrode active material layer to have a good ion conduction path, thereby facilitating the high-capacity performance of the lithium-rich manganese-based positive electrode material.

[0138] In some of these embodiments, the mass percentage of the sulfide electrolyte in the positive electrode active material layer is 5% - 30%.

[0139] As an example, the mass percentages of the positive electrode active material, sulfide electrolyte, conductive agent, and binder mentioned in the context can be determined using the following method: By disassembling the solid-state battery, an active material layer sample of the electrode sheet is obtained. The active material layer can then be analyzed using the following method: The three-dimensional structure of the sample is reconstructed using the nanoscale spatial dynamic resolution and layer-by-layer cutting technology of FIB-SEM. The distribution and percentage of each element are obtained using EDS elemental energy dispersive spectroscopy. Finally, the mass percentages of the positive electrode material, sulfide electrolyte, conductive agent, and binder in the positive electrode active material layer are obtained through software quantitative analysis.

[0140] In this application, the sulfide electrolyte can enhance the ion conductivity of the positive electrode layer and reduce the interfacial impedance, thereby promoting the charge transfer efficiency and full release of the capacity of the positive electrode active material with the outside world.

[0141] In some embodiments, the positive electrode active material layer also contains a conductive agent, the conductive agent having a mass percentage of 0.1%-5% in the positive electrode active material layer; for example, it can be, but is not limited to, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.3%, 2.5%, 2.7%, 3%, 3.3%, 3.5%, 3.8%, 4%, 4.3%, 4.5%, 4.7%, 5%, or a range between the above two values.

[0142] In some alternative embodiments, the conductive agent may optionally include one or more of graphite, carbon nanotubes, carbon nanofibers, carbon black, and graphene.

[0143] As a non-limiting example, the conductive agent includes at least one of superconducting carbon black (SP), conductive agent KS-6, acetylene black, branched Ketjen black ECP, conductive graphite SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs), and graphene and their composite conductive agents. When the cathode material is prepared into a cathode active material layer using a dry method, a cathode conductive agent can be incorporated into the cathode material to improve the conductivity of the cathode active material layer.

[0144] In some embodiments, the positive electrode active material layer also contains a binder, the binder comprising 0.1%-5% by mass in the positive electrode active material layer; for example, it can be, but is not limited to, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.3%, 2.5%, 2.7%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.3%, 4.5%, 4.8%, 5%, or a range between the above two values.

[0145] As a non-limiting example, the binder may optionally include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, hydrogenated nitrile rubber, styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), carboxymethyl chitosan (CMCS), and fluorinated acrylate resins. All of the aforementioned non-limiting positive electrode binders are organic binders and belong to organic components. When the positive electrode material is formulated into a positive electrode slurry using a wet process and then used to prepare the positive electrode active material layer, a positive electrode binder can be incorporated into the positive electrode slurry. This can assist in film formation and also promote the formation of a good electrical contact network between the active particles in the positive electrode active material layer.

[0146] In some embodiments, the positive electrode layer includes a positive electrode current collector and a layer of positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0147] As a non-limiting example, the positive current collector has two surfaces that are opposite to each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0148] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. In the positive 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 positive electrode current collector, the composite current collector may be obtained by forming a metal material on the polymer material substrate. Non-limiting examples of the metal material in the positive electrode current collector may include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. Non-limiting examples of the polymer material substrate in the positive electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0149] In some embodiments, the positive electrode active material may also be a known positive electrode active material for batteries. As a non-limiting example, the positive electrode active material may include one or more of the following materials: lithium transition metal oxides and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds. Non-limiting examples of lithium cobalt oxide may include LiCoO2; non-limiting examples of lithium nickel oxide may include LiNiO2; non-limiting examples of lithium manganese oxide may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxide may include LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 Examples of lithium nickel cobalt aluminum oxides include LiNi, etc. 0.80 Co 0.15 Al 0.05 O2.

[0150] Understandably, lithium (Li) is intercalated and deintercalated during the charging and discharging process of a battery, and the Li content in the positive electrode varies depending on the state of discharge. In the exemplary description of the positive electrode active material in this application, unless otherwise specified, the Li content can be the initial state of the material or a non-initial state after charge-discharge cycles. When the positive electrode active material is applied to the positive electrode in a battery system, the Li content in the positive electrode active material at the positive electrode will typically change after charge-discharge cycles. The Li content can be measured using atomic molar content, but is not limited to this. Regarding "Li content is the initial state of the material," the initial state of the material refers to the state before it is formed into the positive electrode active material layer. It is understood that new materials or substances obtained by appropriate modification based on the listed positive electrode active materials are also within the scope of positive electrode active materials. The aforementioned appropriate modification refers to an acceptable modification method for the positive electrode active material; non-limiting examples include coating modification.

[0151] In the exemplary description of the positive electrode active material in this application, the oxygen (O) content is only a theoretical value. Lattice oxygen release will cause changes in the atomic molar content of oxygen, and the actual O content will fluctuate. The O content can be measured using atomic molar content, but is not limited to this.

[0152] In some embodiments, the positive electrode layer can be prepared by: dry mixing the components used to prepare the positive electrode sheet, such as positive electrode active material particles, sulfide electrolyte particles, positive electrode conductive agent, positive electrode binder, and any other components; then heating and pressurizing the mixed material to knead it into a clump; hot rolling is then performed to form a self-supporting positive electrode sheet; the self-supporting positive electrode sheet is then hot-rolled and bonded to a positive electrode current collector, wherein the self-supporting positive electrode sheet can be bonded to at least one side (single or double sides) of the positive electrode current collector to obtain the positive electrode sheet. Non-limitingly, a dual planetary mixer can be used for dry mixing. Non-limitingly, a kneading and heating process can be used. Non-limitingly, the temperature for hot rolling can be 75°C-85°C, further such as 78°C, 80°C, 82°C, etc. The method of assembling solid-state batteries using positive electrode sheets is suitable for industrial mass production.

[0153] In some embodiments, the positive electrode layer can be prepared by dispersing the components used to prepare the positive electrode sheet, such as positive electrode active material particles, sulfide electrolyte particles, positive electrode conductive agent, positive electrode binder, and any other components, in an organic solvent to form a positive electrode slurry. Further, the positive electrode slurry is coated onto at least one surface of the positive electrode current collector, and after drying, cold pressing, and other processes, the positive electrode sheet is obtained. Cold pressing can be performed using a cold rolling mill. Non-limitingly, the organic solvent in the positive electrode slurry can include one or more of p-xylene, trimethylbenzene, butyl butyrate, heptane, etc., and more specifically, p-xylene. The surface of the positive electrode current collector coated with the positive electrode slurry can be a single surface of the positive electrode current collector or both surfaces of the positive electrode current collector. The solid content of the positive electrode slurry can be 40wt%-80wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000 mPa·s-25000 mPa·s. When coating the positive electrode slurry, the coating density per unit area, measured by dry weight (excluding solvent), can be 15 mg / cm³, based on the amount coated on one side of the positive electrode current collector. 2 -35 mg / cm 2 However, this is not the only possibility. The compaction density of the positive electrode sheet can be 3.0 g / cm³. 3 -3.6g / cm 3 3.3g / cm³ is an option. 3 -3.5g / cm 3 .

[0154] The term "compacted density" as used in this application has a meaning known in the art and is one of the reference indicators for material energy density. In this application, unless otherwise specified, the compacted density of an electrode layer refers to the ratio of the mass of the electrode active material layer to its volume. The compacted density of the positive electrode layer or positive electrode sheet refers to the ratio of the mass of the positive electrode active material layer to its volume, and the compacted density of the negative electrode layer or negative electrode sheet refers to the ratio of the mass of the negative electrode active material layer to its volume.

[0155] In some embodiments, the solid-state battery is an all-solid-state battery; further, it is a lithium-ion all-solid-state battery.

[0156] 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".

[0157] 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.

[0158] 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.

[0159] 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".

[0160] Non-limitingly, a solid-state battery cell (which can be an all-solid-state battery cell) may include a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, with the solid electrolyte layer located between the positive and negative electrode layers. During battery charging and discharging, active ions shuttle between the positive and negative electrode layers, inserting and extracting. The solid electrolyte layer serves to conduct ions between the positive and negative electrode layers and also isolates them, thus preventing short circuits between the positive and negative electrodes.

[0161] In some implementations, a solid-state battery cell includes a solid-state battery cell.

[0162] In some implementations, the solid-state cell is an all-solid-state cell.

[0163] 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.

[0164] Non-limitingly, a solid-state battery cell can be prepared by stacking a positive electrode, a solid electrolyte membrane, and a negative electrode in sequence, placing the solid electrolyte membrane between the positive and negative electrodes, and then performing a temperature isostatic pressing.

[0165] Non-limitingly, a solid-state battery cell can be prepared by stacking a positive electrode membrane, a solid electrolyte membrane, and a negative electrode membrane in sequence, placing the solid electrolyte membrane between the positive electrode membrane and the negative electrode membrane, and then preparing the cell by warm isostatic pressing.

[0166] The negative electrode layer can be formed based on an etched solid electrolyte membrane or provided by a pre-fabricated negative electrode sheet, which can be a negative electrode sheet that is available in the art for use in solid-state batteries.

[0167] The negative electrode sheet can be prepared by dry or wet methods. For example, it can be formed into a film by dry pressing. Alternatively, it can be formed into a film by wet coating.

[0168] In this application, unless otherwise specified, the negative electrode layer includes at least a negative electrode active material layer.

[0169] Unless otherwise stated in this application, the negative electrode sheet includes at least a negative electrode active material layer.

[0170] Unless otherwise stated in this application, the negative electrode active material layer includes at least negative electrode active particles.

[0171] 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".

[0172] 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.

[0173] 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.

[0174] In some embodiments, the negative electrode sheet includes a negative electrode active material layer, the negative electrode active material layer includes negative electrode active particles, and the negative electrode active particles contain negative electrode active substances.

[0175] 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%.

[0176] Non-limiting, the weight percentage of the negative electrode electrolyte particles in the positive electrode active material layer can be 0-30 wt%, preferably 0.1 wt%-30 wt%, and further preferably 5 wt%-20 wt%.

[0177] In some embodiments, the negative electrode active particles or negative electrode active material are lithium indium alloys (InLi alloys).

[0178] In some embodiments, the negative electrode layer or negative electrode sheet is an InLi alloy film.

[0179] 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 anode, 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.

[0180] In some embodiments, the negative electrode sheet 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 substance. 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. 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. In the negative electrode current collector, non-limiting examples of the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0181] 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%.

[0182] In some embodiments, the negative electrode active material layer optionally includes a binder (which may be referred to as a 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 0-10 wt%, more further 0-5 wt%, even more further 1 wt%-5 wt%, and even more preferably 1 wt%-3 wt%.

[0183] 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 the 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%.

[0184] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as negative electrode active 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 sheet 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%-70wt%, optionally 40wt%-60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000mPa·s-10000mPa·s, optionally 3000mPa·s-10000mPa·s. When coating the negative electrode slurry, the coating density per unit area, based on the amount coated on one side of the negative electrode current collector and calculated by dry weight (excluding solvent), can be 1.5 mg / cm³. 2 -22mg / cm 2 However, this is not the only possibility. The compaction density of the negative electrode sheet can be 1.0 g / cm³. 3 -2.0g / cm 3 1.0g / cm³ is an optional value. 3 -1.8g / cm 3 .

[0185] 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.

[0186] 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.

[0187] The types of solid electrolytes present in different film layers of a solid-state battery can be the same or different. For example, the electrolyte particles in the positive electrode layer and the solid electrolyte in the solid electrolyte layer can be the same or different.

[0188] As a non-limiting example, the type of solid electrolyte present in the solid electrolyte layer is a sulfide electrolyte.

[0189] Solid electrolyte membranes or solid electrolyte layers can be prepared using dry methods. In some embodiments, the solid electrolyte layer can be formed by pressing solid electrolyte materials into a solid electrolyte membrane. In other embodiments, the solid electrolyte layer is formed by pressing the constituent raw materials of the solid electrolyte layer onto an electrode layer. In still other embodiments, the solid electrolyte membrane can also be prepared using methods such as fibrosis combined with calendering, melt extrusion, or spraying.

[0190] In this application, the sheet-like solid electrolyte membrane may also be referred to as a solid electrolyte membrane sheet.

[0191] Solid electrolyte layers can also be prepared using a wet process. The electrolyte slurry used includes at least a solid electrolyte and an organic solvent, and usually also includes one or more of a binder and a dispersant.

[0192] In some implementations, the solid electrolyte layer may be formed based on an etched positive electrode.

[0193] In some implementations, the solid electrolyte layer may be formed based on an etched negative electrode.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] 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 1 shows a square solid-state battery cell 5 as an example.

[0198] In some embodiments, referring to FIG2, the outer packaging may include a housing 51 and a cover plate 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 plate 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 the solid-state battery cell 5 may be one or more, which can be selected by those skilled in the art according to actual needs.

[0199] Solid-state batteries can be battery device 4 or battery pack 1.

[0200] 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.

[0201] Figure 3 shows a battery device 4 as an example. Referring to Figure 3, 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 arbitrary manner. Furthermore, the multiple solid-state battery cells 5 can be fixed in place by fasteners.

[0202] 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.

[0203] 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.

[0204] Figures 4 and 5 show a battery pack 1 as an example. Referring to Figures 4 and 5, the battery pack 1 may include a battery compartment and multiple battery devices 4 disposed within the battery compartment. The battery compartment includes an upper compartment 2 and a lower compartment 3, the upper compartment 2 covering the lower compartment 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 compartment.

[0205] In some embodiments, the solid-state battery further includes a solid electrolyte layer, wherein the solid electrolyte in the solid electrolyte layer is a sulfide electrolyte, and the sulfide electrolyte includes one or more of the following: silver sulfide germanium sulfide electrolyte, lithium germanium phosphorus sulfide electrolyte, and lithium sulfide pentaphosphorus sulfide complex electrolyte.

[0206] In some alternative embodiments, the chemical formula of the silver-germanium sulfide electrolyte satisfies Li 6±s P 1-j A j S 5±s-t B t X 1±s , 0≤j<1, 0≤t<1, 0≤s<1, element A includes one or more of Ge, Si, Sn and Sb, element B includes one or more of O, Se and Te, and element X is selected from one or more of Cl, Br, I and F.

[0207] In some of these embodiments, the chemical formula of the lithium-germanium-phosphorus-sulfur sulfide electrolyte satisfies Li10±δ Ge 1-g G g P 2-q Q q S 12-w W w where \(0\leqslant\delta\lt1\), \(0\leqslant g\leqslant1\), \(0\leqslant q\leqslant2\), \(0\leqslant w\lt1\), the G element includes one or more elements of Si and Sn, the Q element includes Sb, and the W element is selected from one or more elements of O, Se, Te, Cl, Br, I and F.

[0208] In some exemplary embodiments, the chemical formula of the lithium sulfide - phosphorus pentasulfide composite - type sulfide electrolyte satisfies \((100 - u - v)Li_2S\cdot uP_2S_5\cdot vM\) m N n where \(0\lt u\lt100\), \(0\leqslant v\lt100\), \(0\leqslant u + v\lt100\), \(0\leqslant m\lt4\), \(0\leqslant n\lt6\), the M element is selected from one or more elements of Li, B, Ge, Si, Sn and Sb, and the N element is selected from one or more elements of S, Se, Te, O, Cl, Br, I and F.

[0209] In some alternative embodiments, the Dv50 of the sulfide electrolyte is \(0.001\ \mu m - 20\ \mu m\).

[0210] In some exemplary embodiments, the Dv50 of the sulfide electrolyte is \(\leqslant1\ \mu m\).

[0211] As a possible embodiment, the Dv50 of the sulfide electrolyte is \(0.05\ \mu m - 1\ \mu m\).

[0212] One or more embodiments of the present application provide a positive electrode plate, including a positive electrode active material layer. The positive electrode active material layer contains a positive electrode active material and a sulfide electrolyte. The positive electrode active material includes positive electrode composite - coated particles. The positive electrode composite - coated particles include a core containing a lithium - rich manganese - based positive electrode material, a first coating layer coated on at least part of the surface of the core, and a second coating layer coated on at least part of the surface of the first coating layer. The first coating layer contains a first coating material, and the first coating material includes a metal oxide with an electronic conductivity \(\geqslant1\ S / cm\). The second coating layer contains a second coating material, and the second coating material includes a lithium - indium - based halide. Among them, the atomic molar ratio of lithium element, indium element and halogen in the lithium - indium - based halide is \(a:b:c\), where \(2\leqslant a\leqslant3\), \(0\lt b\leqslant{1}\), \(4\leqslant c\leqslant6\).

[0213] In some embodiments, the core mainly includes or only contains a lithium - rich manganese - based positive electrode material, the first coating layer mainly includes or only contains the first coating material, and the second coating layer mainly includes or only contains the second coating material.

[0214] In some embodiments, the first coating material of the first coating layer is directly coated on at least a portion of the surface of the lithium-rich manganese-based cathode material, and the second coating material is directly coated on at least a portion of the surface of the first coating material.

[0215] In some embodiments, the general chemical formula of the lithium indium-based halide is Li a In b Q x Cl c , 2≤a≤3, 0<b≤1, 0≤x<1, 0<b+x≤1, 4≤c≤6, Q includes at least one of Sc, Y and Zr.

[0216] In some embodiments, the general chemical formula of the lithium indium-based halide is Li₂In. b Sc 0.666-b Cl4, 0 < b ≤ 0.5.

[0217] In some embodiments, the general chemical formula of the lithium indium-based halide is Li3Y. 1–b In b Cl6, 0.5≤b≤1.

[0218] In some embodiments, the general chemical formula of the lithium indium-based halide is Li 2+b In b Zr 1-b Cl6, 0.5≤b<1.

[0219] In some embodiments, the first coating material includes one or more of Li2RuO3, Fe3O4, Sb-doped SnO2, Sn-doped In2O3, and Al-doped ZnO.

[0220] As one possible implementation, in Sb-doped SnO2, the atomic percentage of Sb is denoted as w1, based on the total number of Sb and Sn atoms, where 0 < w1 ≤ 10 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 1.5 at%, 2 at%, 2.5 at%, 3 at%, 3.5 at%, 4 at%, 4.5 at%, 5 at%, 5.5 at%, 6 at%, 6.5 at%, 7 at%, 7.5 at%, 8 at%, 8.5 at%, 9 at%, 9.5 at%, 10 at%, or any range between any two of the above values.

[0221] In some alternative embodiments, in Sn-doped In₂O₃, the atomic percentage of Sn is denoted as w₂, based on the total number of Sn and In atoms, where 0 < w₂ ≤ 20 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 2 at%, 3 at%, 4 at%, 5 at%, 6 at%, 7 at%, 8 at%, 9 at%, 10 at%, 11 at%, 12 at%, 13 at%, 14 at%, 15 at%, 16 at%, 17 at%, 18 at%, 19 at%, 20 at%, or any range between any two of the above values.

[0222] In some embodiments, in Al-doped ZnO, the atomic percentage of Al is denoted as w3, based on the total number of Al and Zn atoms, where 0 < w3 ≤ 10 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 1.5 at%, 2 at%, 2.5 at%, 3 at%, 3.5 at%, 4 at%, 4.5 at%, 5 at%, 5.5 at%, 6 at%, 6.5 at%, 7 at%, 7.5 at%, 8 at%, 8.5 at%, 9 at%, 9.5 at%, 10 at%, or any range between any two of the above values.

[0223] It should be noted that "at%" in the context refers to the percentage of atoms.

[0224] In some exemplary embodiments, the mass percentage of the first coating material contained in the first coating layer in the positive electrode composite coated particles is 0.1%-5%; for example, it can be, but is not limited to, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, or any range between any two of the above values.

[0225] In some optional embodiments, the first coating material contained in the first coating layer accounts for 0.1%-3% of the mass of the positive electrode composite coated particles.

[0226] In some embodiments, the second coating material contained in the second coating layer accounts for 0.1%-5% of the mass of the positive electrode composite coated particles; for example, it can be, but is not limited to, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, or any range between any two of the above values.

[0227] In one possible implementation, the second coating material contained in the second coating layer accounts for 0.1%-3% of the mass of the positive electrode composite coated particles.

[0228] In some embodiments, the thickness of the first coating layer is 0.1nm-50nm; for example, it can be, but is not limited to, 0.1nm, 0.5nm, 1nm, 3nm, 5nm, 8nm, 10nm, 13nm, 15nm, 18nm, 20nm, 23nm, 25nm, 28nm, 30nm, 33nm, 35nm, 38nm, 40nm, 43nm, 45nm, 48nm, 50nm, or any range between two of the above thicknesses.

[0229] In some alternative implementations, the thickness of the first coating layer is 0.1 nm to 10 nm.

[0230] In some embodiments, the thickness of the second coating layer is 0.1nm-50nm; for example, it can be, but is not limited to, 0.1nm, 0.5nm, 1nm, 3nm, 5nm, 8nm, 10nm, 13nm, 15nm, 18nm, 20nm, 23nm, 25nm, 28nm, 30nm, 33nm, 35nm, 38nm, 40nm, 43nm, 45nm, 48nm, 50nm, or any range between any two of the above thicknesses.

[0231] In some exemplary embodiments, the thickness of the second coating layer is 0.1 nm to 10 nm.

[0232] In some embodiments, the lithium-rich manganese-based cathode material is a layered lithium-rich manganese-based cathode material.

[0233] In some embodiments, the general chemical formula of the lithium-rich manganese-based cathode material satisfies xLi2MnO3·(1-x)LiMO2, where the M element includes one or more elements selected from Ni, Co, Mn, Cr, Fe, Al, Nb, Zr, Mo and Ta, and 0 < x < 1.

[0234] In some embodiments, the Dv50 of the positive electrode composite coated particles is 0.01 μm-20 μm; for example, it can be, but is not limited to, 0.01 μm, 0.05 μm, 0.1 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, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, etc. 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, 20μm, or any range between two of the above particle sizes.

[0235] In some optional embodiments, the Dv50 of the positive electrode composite coated particles is 0.5μm-15μm; for example, it can be, but is not limited to, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, or any range between two of the above particle sizes.

[0236] In some alternative implementations, the Dv50 of the positive electrode composite coated particles is 1 μm-10 μm.

[0237] As one possible implementation, the Dv50 of the sulfide electrolyte is 0.001 μm-20 μm; for example, it can be, but is not limited to, 0.001 μm, 0.005 μm, 0.01 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 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, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, or any range between two of the above particle sizes.

[0238] In some alternative implementations, the Dv50 of the sulfide electrolyte is ≤1 μm.

[0239] In some alternative embodiments, the Dv50 of the sulfide electrolyte is 0.05 μm-1 μm.

[0240] In some embodiments, the sulfide electrolyte includes one or more of argyrodite-type sulfide electrolytes, lithium germanium phosphorus sulfur-based sulfide electrolytes, and lithium sulfide diphosphorus pentasulfide complex-based sulfide electrolytes.

[0241] As a possible embodiment, the chemical formula of the argyrodite-type sulfide electrolyte satisfies Li 6±s P 1-j A j S 5±s-t B t X 1±s , 0 ≤ j < 1, 0 ≤ t < 1, 0 ≤ s < 1, the A element includes one or more elements selected from Ge, Si, Sn, and Sb, the B element includes one or more elements selected from O, Se, and Te, and the X element is selected from one or more elements of Cl, Br, I, and F.

[0242] In some alternative embodiments, the chemical formula of the lithium germanium phosphorus sulfur-based sulfide electrolyte satisfies Li 10±δ Ge 1-g G g P 2-q Q q S 12-w W w , 0 ≤ δ < 1, 0 ≤ g ≤ 1, 0 ≤ q ≤ 2, 0 ≤ w < 1, the G element includes one or more elements selected from Si and Sn, the Q element includes Sb, and the W element is selected from one or more elements of O, Se, Te, Cl, Br, I, and F.

[0243] In some of these embodiments, the chemical formula of the lithium sulfide diphosphorus pentasulfide complex-based sulfide electrolyte satisfies (100 - u - v)Li2S·uP2S5·vM m N n , 0 < u < 100, 0 ≤ v < 100, 0 ≤ u + v < 100, 0 ≤ m < 4, 0 ≤ n < 6, the M element is selected from one or more elements of Li, B, Ge, Si, Sn, and Sb, and the N element is selected from one or more elements of S, Se, Te, O, Cl, Br, I, and F. ​​​​As one possible implementation, the positive electrode active material accounts for 70%-95% of the mass of the positive electrode active material layer.

[0246] In some exemplary embodiments, the mass percentage of the sulfide electrolyte in the positive electrode active material layer is 0.1%-50%; for example, it can be, but is not limited to, 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 23%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 43%, 45%, 48%, 50%, or any range between any two of the above values.

[0247] In some of these embodiments, the sulfide electrolyte accounts for 5%-30% of the mass of the positive electrode active material layer.

[0248] In some embodiments, the positive electrode active material layer also contains a conductive agent, the conductive agent having a mass percentage of 0.1%-5% in the positive electrode active material layer; for example, it can be, but is not limited to, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.3%, 2.5%, 2.7%, 3%, 3.3%, 3.5%, 3.8%, 4%, 4.3%, 4.5%, 4.7%, 5%, or a range between the above two values.

[0249] In some alternative embodiments, the conductive agent may optionally include one or more of graphite, carbon nanotubes, carbon nanofibers, carbon black, and graphene.

[0250] As a non-limiting example, the conductive agent includes at least one of superconducting carbon black (SP), conductive agent KS-6, acetylene black, branched Ketjen black ECP, conductive graphite SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs), and graphene and their composite conductive agents. When the cathode material is prepared into a cathode active material layer using a dry method, a cathode conductive agent can be incorporated into the cathode material to improve the conductivity of the cathode active material layer.

[0251] In some embodiments, the positive electrode active material layer also contains a binder, the binder comprising 0.1%-5% by mass in the positive electrode active material layer; for example, it can be, but is not limited to, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.3%, 2.5%, 2.7%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.3%, 4.5%, 4.8%, 5%, or a range between the above two values.

[0252] As a non-limiting example, the adhesive may optionally include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, hydrogenated nitrile rubber, styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), carboxymethyl chitosan (CMCS), and fluorinated acrylate resins.

[0253] One or more embodiments of this application provide a positive electrode active material, including a core containing a lithium-rich manganese-based positive electrode material, a first coating layer covering at least a portion of the surface of the core, and a second coating layer covering at least a portion of the surface of the first coating layer; the first coating layer includes a first coating material, which includes a metal oxide with an electronic conductivity ≥1 S / cm; the second coating layer includes a second coating material, which includes a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium, and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, 4≤c≤6.

[0254] In some implementations, the core mainly includes or contains only lithium-rich manganese-based cathode material, the first coating layer mainly includes or contains only the first coating material, and the second coating layer mainly includes or contains only the second coating material.

[0255] In some embodiments, the first coating material of the first coating layer is directly coated on at least a portion of the surface of the lithium-rich manganese-based cathode material, and the second coating material is directly coated on at least a portion of the surface of the first coating material.

[0256] In some embodiments, the general chemical formula of the lithium indium-based halide is Li a In b Q x Cl c , 2≤a≤3, 0<b≤1, 0≤x<1, 0<b+x≤1, 4≤c≤6, Q includes at least one of Sc, Y and Zr.

[0257] In some embodiments, the general chemical formula of the lithium indium-based halide is Li₂In. b Sc 0.666-b Cl4, 0 < b ≤ 0.5.

[0258] In some embodiments, the general chemical formula of the lithium indium-based halide is Li3Y. 1–b In b Cl6, 0.5≤b≤1.

[0259] In some embodiments, the general chemical formula of the lithium indium-based halide is Li 2+b In b Zr 1-b Cl6, 0.5≤b<1.

[0260] In some embodiments, the first coating material includes one or more of Li2RuO3, Fe3O4, Sb-doped SnO2, Sn-doped In2O3, and Al-doped ZnO.

[0261] As one possible implementation, in Sb-doped SnO2, the atomic percentage of Sb is denoted as w1, based on the total number of Sb and Sn atoms, where 0 < w1 ≤ 10 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 1.5 at%, 2 at%, 2.5 at%, 3 at%, 3.5 at%, 4 at%, 4.5 at%, 5 at%, 5.5 at%, 6 at%, 6.5 at%, 7 at%, 7.5 at%, 8 at%, 8.5 at%, 9 at%, 9.5 at%, 10 at%, or any range between any two of the above values.

[0262] In some alternative embodiments, in Sn-doped In₂O₃, the atomic percentage of Sn is denoted as w₂, based on the total number of Sn and In atoms, where 0 < w₂ ≤ 20 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 2 at%, 3 at%, 4 at%, 5 at%, 6 at%, 7 at%, 8 at%, 9 at%, 10 at%, 11 at%, 12 at%, 13 at%, 14 at%, 15 at%, 16 at%, 17 at%, 18 at%, 19 at%, 20 at%, or any range between any two of the above values.

[0263] In some embodiments, in Al-doped ZnO, the atomic percentage of Al is denoted as w3, based on the total number of Al and Zn atoms, where 0 < w3 ≤ 10 at%. For example, it can be, but is not limited to, 0.01 at%, 0.02 at%, 0.04 at%, 0.06 at%, 0.08 at%, 0.1 at%, 0.2 at%, 0.4 at%, 0.6 at%, 0.8 at%, 1 at%, 1.5 at%, 2 at%, 2.5 at%, 3 at%, 3.5 at%, 4 at%, 4.5 at%, 5 at%, 5.5 at%, 6 at%, 6.5 at%, 7 at%, 7.5 at%, 8 at%, 8.5 at%, 9 at%, 9.5 at%, 10 at%, or any range between any two of the above values.

[0264] It should be noted that "at%" in the context refers to the percentage of atoms.

[0265] In some exemplary embodiments, the mass percentage of the first coating material contained in the first coating layer in the positive electrode composite coated particles is 0.1%-5%; for example, it can be, but is not limited to, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, or any range between any two of the above values.

[0266] In some optional embodiments, the first coating material contained in the first coating layer accounts for 0.1%-3% of the mass of the positive electrode composite coated particles.

[0267] In some embodiments, the second coating material contained in the second coating layer accounts for 0.1%-5% of the mass of the positive electrode composite coated particles; for example, it can be, but is not limited to, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, or any range between any two of the above values.

[0268] In one possible implementation, the second coating material contained in the second coating layer accounts for 0.1%-3% of the mass of the positive electrode composite coated particles.

[0269] In some embodiments, the thickness of the first coating layer is 0.1nm-50nm; for example, it can be, but is not limited to, 0.1nm, 0.5nm, 1nm, 3nm, 5nm, 8nm, 10nm, 13nm, 15nm, 18nm, 20nm, 23nm, 25nm, 28nm, 30nm, 33nm, 35nm, 38nm, 40nm, 43nm, 45nm, 48nm, 50nm, or any range between two of the above thicknesses.

[0270] In some alternative implementations, the thickness of the first coating layer is 0.1 nm to 10 nm.

[0271] In some embodiments, the thickness of the second coating layer is 0.1nm-50nm; for example, it can be, but is not limited to, 0.1nm, 0.5nm, 1nm, 3nm, 5nm, 8nm, 10nm, 13nm, 15nm, 18nm, 20nm, 23nm, 25nm, 28nm, 30nm, 33nm, 35nm, 38nm, 40nm, 43nm, 45nm, 48nm, 50nm, or any range between any two of the above thicknesses.

[0272] In some exemplary embodiments, the thickness of the second coating layer is 0.1 nm to 10 nm.

[0273] In some embodiments, the lithium-rich manganese-based cathode material is a layered lithium-rich manganese-based cathode material.

[0274] In some embodiments, the general chemical formula of the lithium-rich manganese-based cathode material satisfies xLi2MnO3·(1-x)LiMO2, where the M element includes one or more elements selected from Ni, Co, Mn, Cr, Fe, Al, Nb, Zr, Mo and Ta, and 0 < x < 1.

[0275] In some embodiments, the Dv50 of the positive electrode composite coated particles is 0.01 μm-20 μm; for example, it can be, but is not limited to, 0.01 μm, 0.05 μm, 0.1 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, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, etc. 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, 20μm, or any range between two of the above particle sizes.

[0276] In some optional embodiments, the Dv50 of the positive electrode composite coated particles is 0.5μm-15μm; for example, it can be, but is not limited to, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, or any range between two of the above particle sizes.

[0277] In some alternative implementations, the Dv50 of the positive electrode composite coated particles is 1 μm-10 μm.

[0278] One or more embodiments of this application provide a method for preparing a positive electrode active material, the positive electrode active material comprising positive electrode composite coated particles, the method for preparing the positive electrode active material comprising preparing the positive electrode composite coated particles, the preparation of the positive electrode composite coated particles comprising:

[0279] A mixed powder containing a core of lithium-rich manganese-based cathode material and a first coating agent is subjected to a first heat treatment to form a first coating layer on at least a portion of the surface of the core, thereby obtaining an intermediate; a mixture containing the intermediate and a second coating agent is subjected to a second heat treatment to form a second coating layer on at least a portion of the surface of the intermediate.

[0280] The first coating agent comprises a metal oxide with an electronic conductivity ≥1 S / cm; the second coating agent comprises a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, 4≤c≤6.

[0281] One or more embodiments of this application provide an electrical device including the solid-state battery described above.

[0282] In some embodiments, the electrical device includes at least one of the solid-state batteries of any of the embodiments provided in this application.

[0283] 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.

[0284] As an electrical device, solid-state batteries can be selected based on its usage requirements.

[0285] Figure 6 shows 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.

[0286] 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.

[0287] One or more embodiments of this application provide the application of the above-described solid-state battery, the above-described positive electrode sheet, or the above-described positive electrode active material in supplying and / or storing electrical energy, the application including at least one process of charging and discharging at a voltage of 4.5V or higher.

[0288] Example

[0289] 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 technology or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0290] I. Solid-state battery fabrication

[0291] Example 1

[0292] Step 1: Preparation of the positive electrode sheet

[0293] Weigh out lithium-rich manganese-based cathode material Li 1.2 Ni 0.13 Co 0.13 Mn 0.54O2 and Li2RuO3 (the first coating material) powders were mixed uniformly using a dry coating equipment. The uniformly mixed material was then heat-treated at 600℃ for 1 hour in an oxygen atmosphere to prepare the lithium-rich manganese-based cathode material Li2RuO3. 1.2 Ni 0.13 Co 0.13 Mn 0.54 An intermediate is prepared by coating at least a portion of the surface of O2 with Li2RuO3.

[0294] Weigh the intermediate and Li3InCl6 (second coating material) powder at a mass ratio of 97:3, add them to a mechanical fusion machine, and run at 3000 rpm for 1 hour to coat at least part of the surface of the intermediate with Li3InCl6 to obtain the positive electrode active material.

[0295] The above-prepared positive electrode active material, sulfide electrolyte Li6PS5Cl (LPSCl, Dv50 of 700nm), conductive agent vapor-grown carbon fiber (VGCF), and binder polytetrafluoroethylene (PTFE) were weighed in a ratio of 70:26:3:1 and mixed evenly in a double planetary mixer. Then, the evenly mixed powder was heated and kneaded into a lumpy material in an internal mixer, and then hot-rolled at 80°C to form a self-supporting positive electrode sheet. Finally, it was combined with a single-sided current collector Al foil hot-rolled to obtain the positive electrode sheet.

[0296] Step 2: Preparation of the negative electrode sheet

[0297] InLi alloy anode is used.

[0298] Step 3, Solid electrolyte layer

[0299] The sulfide electrolyte Li6PS5Cl (LPSCl) was selected.

[0300] Step 4: Assembly

[0301] First, weigh 100 mg of sulfide electrolyte LPSCl and add it to the battery mold. Pressurize to obtain an electrolyte sheet. Then, place the positive electrode sheet on one side of the electrolyte sheet and add InLi alloy as the negative electrode sheet on the other side. Pressurize at 500 MPa for 5 minutes to assemble an all-solid-state battery.

[0302] Example 2-21

[0303] The differences between the preparation methods of Examples 2-21 and the preparation method of Example 1 are detailed in Table 1-1.

[0304] Comparative Example 1

[0305] The difference between the preparation method of Comparative Example 1 and the preparation method of Example 1 is that: in Comparative Example 1, lithium-rich manganese-based cathode material Li was used when preparing the cathode.1.2 Ni 0.13 Co 0.13 Mn 0.54 O2 is used as the positive electrode active material, and everything else is the same.

[0306] Comparative Example 2

[0307] The difference between the preparation method of Comparative Example 2 and the preparation method of Example 1 is that: in Comparative Example 2, Li2ZrO3 was used to coat the lithium-rich manganese-based cathode material Li during the preparation of the positive electrode. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2, everything else is the same.

[0308] Comparative Example 3

[0309] The difference between the preparation method of Comparative Example 3 and the preparation method of Example 1 is that in Comparative Example 3, when preparing the positive electrode sheet, only Li3InCl6 was used to coat the lithium-rich manganese-based positive electrode material Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2, everything else is the same.

[0310] Comparative Example 4

[0311] The difference between the preparation method of Comparative Example 4 and that of Example 1 is that in Comparative Example 4, when preparing the positive electrode sheet, only Li2RuO3 was used to coat the lithium-rich manganese-based positive electrode material Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2, everything else is the same.

[0312] Comparative Example 5

[0313] The difference between the preparation method of Comparative Example 5 and the preparation method of Example 1 is that: in Comparative Example 5, when preparing the positive electrode sheet, the weighed lithium-rich manganese-based positive electrode material Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2 is physically mixed with Li2RuO3 and Li3InCl6 and then used to prepare the positive electrode sheet. This mixture is not used in the preparation of lithium-rich manganese-based materials such as Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 A coating layer forms on the surface of O2.

[0314] Comparative Example 6

[0315] The difference between the preparation method of Comparative Example 6 and that of Example 1 is that in Comparative Example 6, when preparing the positive electrode sheet, Li3InCl6 powder was first used to prepare the lithium-rich manganese-based positive electrode material Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 The first coating is performed using O2, followed by a second coating using Li2RuO3 powder; the specific preparation process of the positive electrode active material is as follows:

[0316] Weigh out lithium-rich manganese-based cathode material Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2 and Li3InCl6 (the first coating material) powders were added to a mechanical fusion machine and run at 3000 rpm for 1 hour to fused the lithium-rich manganese-based cathode material Li... 1.2 Ni 0.13 Co 0.13 Mn 0.54 To prepare an intermediate, at least a portion of the surface of O2 is coated with Li3InCl6.

[0317] The intermediate and Li2RuO3 (second coating material) powder were mixed uniformly using a dry coating device. The uniformly mixed material was then heat-treated at 600°C for 1 hour in an oxygen atmosphere to coat at least a portion of the surface of the intermediate with Li2RuO3, thus obtaining the positive electrode active material. The all-solid-state lithium-ion batteries prepared in the above embodiments and comparative examples were subjected to structural parameter tests in at least the following aspects:

[0318] The percentage of the mass of the coating material in the positive electrode active material relative to the mass of the lithium-rich manganese-based positive electrode material, the thickness of each coating layer, the Dv50 of the positive electrode active material, and the Dv50 of the sulfide electrolyte, etc.

[0319] The test results of the preparation parameters and structural parameters of the above embodiments are shown in Table 1-1. The test results of the preparation parameters and structural parameters of the above comparative examples are shown in Table 1-2.

[0320] Table 1-1

[0321] Table 1-2

[0322] In Tables 1-1 and 1-2, Dv501 represents the Dv50 of the sulfide electrolyte used in the preparation of the positive electrode sheet; Dv502 represents the Dv50 of the positive electrode active material in the obtained solid-state battery; Dv503 represents the Dv50 of the sulfide electrolyte contained in the positive electrode sheet of the obtained solid-state battery; Dv504 represents the Dv50 of the lithium-rich manganese-based positive electrode material used in the preparation of the positive electrode active material; w1 represents the mass percentage of the first coating material in the positive electrode active material of the obtained solid-state battery; w2 represents the mass percentage of the second coating material in the positive electrode active material of the obtained solid-state battery; n1 represents the thickness of the first coating layer in the positive electrode active material of the obtained solid-state battery; and n2 represents the thickness of the second coating layer in the positive electrode active material of the obtained solid-state battery.

[0323] The mass percentage of the coating material in the positive electrode active material of the solid-state battery was determined by the following method: a positive electrode sheet was taken from the obtained solid-state battery cell, and the sulfide electrolyte in the positive electrode sheet was washed away by ethanol to obtain positive electrode powder. The contents of the main elements Ni, Co, Mn and coating elements Ru, In, etc. were determined by ICP (inductively coupled plasma spectroscopy). The percentage of coating material in the first coating layer and the second coating layer could be calculated.

[0324] The thickness of the coating layer in the positive electrode active material of the solid-state battery is obtained by the following measurement method: First, a positive electrode sheet is taken from the solid-state battery cell, and then the individual positive electrode particles are cut and thinned by FIB (Focused Ion Beam) to obtain a TEM (Transmission Electron Microscopy) sample. Then, the thickness of the first coating layer and the second coating layer can be obtained by imaging analysis of TEM.

[0325] The Dv502 of the positive electrode active material in the solid-state battery was obtained by the following measurement method: First, a positive electrode sheet was removed from the solid-state battery cell, and then the cross-section of the positive electrode sheet was obtained by CP (ion beam cross-section grinding). Then, it was observed by SEM, and the size of the positive electrode particles in the field of view was counted by software. Then, the Dv502 of the positive electrode active material was calculated.

[0326] The Dv503 of the sulfide electrolyte contained in the positive electrode of the solid-state battery was obtained by the following method: First, a positive electrode was removed from the solid-state battery cell, and then the cross-section of the positive electrode was obtained by CP (ion beam cross-section grinding). Then, it was observed by SEM, and the size of the positive electrode particles in the field of view was counted by software. Then, the Dv503 of the sulfide electrolyte was calculated.

[0327] II. Performance Testing

[0328] The solid-state batteries prepared in the above embodiments and comparative examples were subjected to initial discharge capacity testing, initial coulombic efficiency testing, and cycle performance testing. The voltage test window for the batteries was 2.0V-4.8V vs. Li+ / Li, and the batteries were tested at 25°C, where 1C = 200mA / g. The test methods are as follows:

[0329] First discharge capacity test: The assembled solid-state battery was charged to 4.18V (4.8V for lithium potential) at a current density of 0.1C, left to stand for 10 minutes, and then discharged to 1.38V (2.0V for lithium potential) at a current density of 0.1C to obtain the first discharge capacity of the battery.

[0330] First Coulomb Efficiency: The first Coulomb efficiency of a battery is obtained by dividing the first discharge capacity obtained from the test at 0.1C by the first charge capacity.

[0331] Cyclic testing: The assembled solid-state battery was first subjected to constant current charge-discharge for 3 cycles at a current density of 0.1C to obtain the initial discharge capacity and initial coulombic efficiency. Then, a long-term cycle test was conducted at a current density of 0.33C for 200 cycles, and the cycle capacity retention rate of the battery was calculated.

[0332] The test results of the above embodiments and comparative examples are shown in Table 2.

[0333] Table 2

[0334] A comparison of the results of Examples 1-21 and Comparative Examples 1-6 shows that by using a first coating material (a metal oxide with an electronic conductivity ≥ 1 S / cm) and a second coating material (lithium indium-based halide) to form a composite coating layer on at least a portion of the surface of the lithium-rich manganese-based cathode material, it is beneficial to improve the electronic conductivity and ionic conductivity of the cathode active material and suppress oxygen release from the lithium-rich manganese-based cathode material, thereby improving the discharge capacity and cycle performance of the cathode active material, and further improving the discharge capacity and cycle performance of the solid-state battery using this cathode active material, while also benefiting the first-efficiency and rate performance of the solid-state battery.

[0335] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0336] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A solid-state battery, comprising a positive electrode layer, the positive electrode layer comprising a positive electrode active material layer, the positive electrode active material layer comprising a positive electrode active material and a sulfide electrolyte, the positive electrode active material comprising positive electrode composite coated particles, the positive electrode composite coated particles comprising: The core comprises a lithium-rich manganese-based cathode material; A first coating layer is coated on at least a portion of the surface of the core, the first coating layer comprising a first coating material comprising a metal oxide with an electronic conductivity ≥1 S / cm; and A second coating layer is applied to at least a portion of the surface of the first coating layer. The second coating layer comprises a second coating material, which includes a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium, and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, and 4≤c≤6.

2. The solid-state battery according to claim 1, wherein, The general chemical formula of the lithium indium-based halide is Li a In b Q x Cl c , 2≤a≤3, 0<b≤1, 0≤x<1, 0<b+x≤1, 4≤c≤6, Q includes at least one of Sc, Y and Zr.

3. The solid-state battery according to any one of claims 1 to 2, wherein, The first coating material includes one or more of Li2RuO3, Fe3O4, Sb-doped SnO2, Sn-doped In2O3, and Al-doped ZnO.

4. The solid-state battery according to claim 3, wherein, The first coating material includes at least one of the following features (1)-(3): (1) In Sb-doped SnO2, the total number of Sb and Sn atoms is used as the benchmark, and the atomic percentage of Sb is recorded as w1, where 0 < w1 ≤ 10 at%. (2) In Sn-doped In2O3, the atomic percentage of Sn is recorded as w2, with the total number of Sn and In atoms as the benchmark, and 0 < w2 ≤ 20 at%. (3) In Al-doped ZnO, the total number of Al and Zn atoms is used as the benchmark, and the percentage of Al atoms is denoted as w3, where 0 < w3 ≤ 10at%.

5. The solid-state battery according to any one of claims 1 to 4, wherein, The first covering layer has at least one of the following features (1)-(2): (1) The mass percentage of the first coating material contained in the first coating layer in the positive electrode composite coated particles is 0.1%-5%; (2) The thickness of the first coating layer is 0.1nm-50nm.

6. The solid-state battery according to any one of claims 1 to 5, wherein, The first covering layer has at least one of the following features (1)-(2): (1) The mass percentage of the first coating material contained in the first coating layer in the positive electrode composite coated particles is 0.1%-3%; (2) The thickness of the first coating layer is 0.1nm-10nm.

7. The solid-state battery according to any one of claims 1 to 6, wherein, The second covering layer has at least one of the following features (1)-(2): (1) The mass percentage of the second coating material contained in the second coating layer in the positive electrode composite coated particles is 0.1%-5%; (2) The thickness of the second coating layer is 0.1nm-50nm.

8. The solid-state battery according to any one of claims 1 to 7, wherein, The second covering layer has at least one of the following features (1)-(2): (1) The mass percentage of the second coating material contained in the second coating layer in the positive electrode composite coated particles is 0.1%-3%; (2) The thickness of the second coating layer is 0.1nm-10nm.

9. The solid-state battery according to any one of claims 1 to 8, wherein, The lithium-rich manganese-based cathode material is a layered lithium-rich manganese-based cathode material.

10. The solid-state battery according to any one of claims 1 to 9, wherein, The general chemical formula of the lithium-rich manganese-based cathode material satisfies xLi2MnO3·(1-x)LiMO2, where M is one or more of the elements selected from Ni, Co, Mn, Cr, Fe, Al, Nb, Zr, Mo and Ta, and 0 < x < 1.

11. The solid-state battery according to any one of claims 1 to 10, wherein, The Dv50 of the positive electrode composite coated particles is 0.5μm-15μm.

12. The solid-state battery according to any one of claims 1 to 11, wherein, The Dv50 of the positive electrode composite coated particles is 1μm-10μm.

13. The solid-state battery according to any one of claims 1 to 12, wherein, The Dv50 of the sulfide electrolyte is 0.001 μm-20 μm.

14. The solid-state battery according to any one of claims 1 to 13, wherein, The Dv50 of the sulfide electrolyte is 0.05μm-1μm.

15. The solid-state battery according to any one of claims 1 to 14, wherein, The sulfide electrolyte includes one or more of the following: silver-germanium sulfide type sulfide electrolyte, lithium-germanium-phosphorus-sulfide type sulfide electrolyte, and lithium sulfide-phosphorus pentasulfide complex type sulfide electrolyte.

16. The solid-state battery according to claim 15, wherein, The sulfide electrolyte includes at least one of the following features (1)-(3): (1) The chemical formula of the silver-germanium sulfide electrolyte satisfies Li 6±s P 1-j A j S 5±s-t B t X 1±s , 0≤j<1, 0≤t<1, 0≤s<1, element A includes one or more elements from Ge, Si, Sn and Sb, element B includes one or more elements from O, Se and Te, and element X is selected from one or more elements from Cl, Br, I and F; (2) The chemical formula of the lithium-germanium-phosphorus-sulfur electrolyte satisfies Li 10±δ Ge 1-g G g P 2-q Q q S 12-w W w , 0≤δ<1, 0≤g≤1, 0≤q≤2, 0≤w<1, G element includes one or more elements from Si and Sn, Q element includes Sb, W element is selected from one or more elements from O, Se, Te, Cl, Br, I and F; (3) The chemical formula of the lithium sulfide - phosphorus pentasulfide composite - type sulfide electrolyte satisfies (100 - u - v)Li2S·uP2S5·vM m N n , where 0 < u < 100, 0 ≤ v < 100, 0 ≤ u + v < 100, 0 ≤ m < 4, 0 ≤ n < 6, the M element is selected from one or more elements of Li, B, Ge, Si, Sn, and Sb, and the N element is selected from one or more elements of S, Se, Te, O, Cl, Br, I, and F.

17. The solid-state battery according to any one of claims 1 to 16, wherein, The solid-state battery has at least one of the following features (1)-(2): (1) The positive electrode active material accounts for 50%-99% of the mass of the positive electrode active material layer; (2) The sulfide electrolyte accounts for 0.1%-50% of the mass of the positive electrode active material layer.

18. The solid-state battery according to any one of claims 1 to 17, wherein, The solid-state battery has at least one of the following features (1)-(2): (1) The positive electrode active material accounts for 70%-95% of the mass of the positive electrode active material layer; (2) The sulfide electrolyte accounts for 5%-30% of the mass of the positive electrode active material layer.

19. The solid-state battery according to any one of claims 1 to 18, wherein, The solid-state battery is a lithium-ion all-solid-state battery.

20. A positive electrode sheet, comprising a positive active material layer, the positive active material layer comprising a positive active material and a sulfide electrolyte, the positive active material comprising positive composite coated particles, the positive composite coated particles comprising: The core comprises a lithium-rich manganese-based cathode material; A first coating layer covers at least a portion of the surface of the core, the first coating layer comprising a first coating material having an electronic conductivity ≥ 1 S / cm; and A second coating layer is applied to at least a portion of the surface of the first coating layer. The second coating layer comprises a second coating material, which includes a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium, and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, and 4≤c≤6.

21. The positive electrode sheet according to claim 20, wherein, The positive electrode layer in the solid-state battery according to any one of claims 1 to 18.

22. A positive electrode active material, said positive electrode active material comprising positive electrode composite coated particles, said positive electrode composite coated particles comprising: The core comprises a lithium-rich manganese-based cathode material; A first coating layer covers at least a portion of the surface of the core, the first coating layer comprising a first coating material having an electronic conductivity ≥ 1 S / cm; and A second coating layer is applied to at least a portion of the surface of the first coating layer. The second coating layer comprises a second coating material, which includes a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium, and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, and 4≤c≤6.

23. The positive electrode active material according to claim 22, wherein, The positive electrode active material in the solid-state battery according to any one of claims 1 to 12.

24. A method for preparing a positive electrode active material, wherein the positive electrode active material comprises positive electrode composite coated particles, and the method for preparing the positive electrode active material comprises preparing the positive electrode composite coated particles, wherein the preparation of the positive electrode composite coated particles comprises: An intermediate is prepared by subjecting a mixed powder containing a core of lithium-rich manganese-based cathode material and a first coating agent to a first heat treatment to form a first coating layer on at least a portion of the surface of the core. The mixture comprising the intermediate and the second coating agent is subjected to a second heat treatment to form a second coating layer on at least a portion of the surface of the intermediate; The first coating agent comprises a metal oxide with an electronic conductivity ≥1 S / cm; the second coating agent comprises a lithium indium-based halide, wherein the atomic molar ratio of lithium, indium and halogen in the lithium indium-based halide is a:b:c, 2≤a≤3, 0<b≤1, 4≤c≤6.

25. An electrical device comprising a solid-state battery as described in any one of claims 1 to 19.

26. The use of the solid-state battery of any one of claims 1 to 19, the positive electrode of claim 20 or 21, or the positive active material of claim 22 or 23 in supplying and / or storing electrical energy, said use comprising at least one process of charging and discharging at a voltage of 4.5V or higher.

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