Solid-state battery and preparation method therefor, and electric device

Abstract

The application relates to a solid-state battery, a preparation method thereof and an electric device. The solid-state battery comprises a positive electrode layer, the positive electrode layer comprises a positive electrode active layer, the positive electrode active layer comprises a composite-coated positive electrode material, the composite-coated positive electrode material comprises a positive electrode active body and a coating layer located on the surface of the positive electrode active body, and the coating layer comprises a carbon conductive substance and a conductive polymer. The solid-state battery has significantly improved cycle performance. The solid-state battery has significantly improved cycle performance.

Description

Technical Field

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

[0002] The statements herein are provided only as background information in connection with this application and do not necessarily constitute prior art.

[0003] Solid-state batteries, represented by all-solid-state batteries, have attracted much attention due to their excellent energy density. Solid-state batteries do not use a traditional liquid electrolyte; instead, the component particles in a solid-solid contact are connected, and the transport of active ions largely depends on the interfacial contact between solid particles. However, voids inevitably exist between the component particles in solid-state batteries, which can easily hinder interfacial charge transport. The solid-solid interface contact problem in solid-state batteries limits their performance, leading to issues such as poor cycle stability. During charge-discharge cycles, the positive electrode active material in the positive electrode component undergoes volume changes due to the reversible extraction and insertion of active ions. When active ions are extracted, the voids at the positive electrode interface further expand, increasing battery impedance and affecting the capacity utilization and cycle stability of the solid-state battery. Summary of the Invention

[0004] According to various embodiments and examples of this application, this application provides a solid-state battery, a method for preparing the same, and an electrical device thereof. This solid-state battery exhibits significantly improved cycle performance.

[0005] In a first aspect, this application provides a solid-state battery comprising a positive electrode layer, the positive electrode layer including a positive electrode active layer, the positive electrode active layer including a composite coated positive electrode material, the composite coated positive electrode material including a positive electrode active body and a coating layer located on the surface of the positive electrode active body, the coating layer including a carbon conductive material and a conductive polymer. This solid-state battery exhibits significantly improved cycle performance.

[0006] In some embodiments, a solid-state battery is provided, comprising a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially, wherein the positive electrode layer includes a positive electrode active layer, the positive electrode active layer includes a positive electrode active material, the positive electrode active material includes a composite coated positive electrode material, the composite coated positive electrode material includes a positive electrode active body and a coating layer located on the surface of the positive electrode active body, the coating layer includes a carbon conductive material and a conductive polymer.

[0007] A composite coated cathode material is introduced into the cathode layer. A coating layer consisting of a carbon conductive material and a conductive polymer is formed on the surface of the cathode active body. The conductive polymer is a soft polymer material with high electronic conductivity, while the carbon conductive material has excellent electron transport capabilities. On the one hand, the flexibility of the conductive polymer allows it to directly and tightly contact the cathode active body, thereby effectively suppressing the volume deformation of the cathode active material using the viscoelasticity of the conductive polymer. On the other hand, the high electronic conductivity of the conductive polymer and the excellent electron transport capabilities of the carbon conductive material can be combined to enhance the electron conduction between the cathode active material and other cathode components. Not wanting to be limited by any theory, by introducing a composite coated cathode material into the cathode layer, the solid-solid contact stability of the cathode interface in solid-state batteries can be significantly improved, and the electron conduction capability of the cathode layer can be enhanced. Therefore, the capacity utilization of the cathode and the cycle stability of the solid-state battery can be significantly improved, thus significantly enhancing the cycle performance of the solid-state battery.

[0008] The improvement described in any part of the context of this application is not intended to be limited by any theoretical constraints.

[0009] By improving the solid-solid contact stability of the positive electrode interface and enhancing the electronic conductivity of the positive electrode layer, the impedance of the positive electrode interface can be reduced, thereby reducing the internal resistance of the battery.

[0010] In some embodiments, at least a portion of the carbon conductive material and the conductive polymer are present as a carbon composite conductive polymer material; in the carbon composite conductive polymer material, the carbon conductive material is dispersed in a polymer matrix formed by the conductive polymer.

[0011] By incorporating a carbon composite conductive polymer material into the coating layer of the composite-coated cathode material, the carbon conductive material and the conductive polymer exist in a composite manner. This allows for a better synergistic effect between the conductive polymer and the carbon conductive material. On one hand, it facilitates more and better close contact between the conductive polymer and the surface of the cathode active material, thereby better suppressing the volume deformation of the cathode active material. On the other hand, it improves the uniformity of the conductivity on the surface of the cathode active material, allowing active ions to be more uniformly embedded at different sites on the cathode active material, reducing local stress concentration caused by differences in active ion embedding rates, and improving the structural stability of the cathode active material. Furthermore, the close composite between the carbon conductive material and the conductive polymer inhibits or prevents the carbon conductive material from detaching from the surface of the cathode active material, improving the compositional stability of the coating layer, and thus improving the conductivity stability of the carbon composite conductive polymer material surface. Based on the synergistic effect of the aforementioned multiple actions, the capacity utilization and cycle performance of solid-state batteries can be better improved.

[0012] In some embodiments, the carbon composite conductive polymer material satisfies one or more of the following characteristics:

[0013] (t1) In the carbon composite conductive polymer material, the mass percentage of the carbon conductive substance relative to the conductive polymer is 0.5% to 10%;

[0014] (t2) The carbon composite conductive polymer material in the coating layer has a mass percentage of 80% to 100%;

[0015] (t3) The carbon composite conductive polymer material in the composite coated cathode material has a mass percentage of 0.45% to 10%, and can be selected as 1% to 5%.

[0016] In some embodiments, the carbon composite conductive polymer material satisfies one or more of the following characteristics:

[0017] (t1') In the carbon composite conductive polymer material, the mass percentage of the carbon conductive substance relative to the conductive polymer is 0.5% to 5%, optionally 0.5% to 2.5%;

[0018] (t2') The carbon composite conductive polymer material in the coating layer has a mass percentage of 90% to 100%;

[0019] (t3') The carbon composite conductive polymer material in the composite coated cathode material has a mass percentage of 1% to 3%.

[0020] By controlling the mass percentage of carbon conductive material relative to conductive polymer in carbon composite conductive polymer materials within the aforementioned range, it is beneficial to achieve better and more stable composite between conductive polymer and carbon conductive material, better leverage the synergistic effect between conductive polymer and carbon conductive material, and better improve the cycle performance of solid-state batteries.

[0021] By controlling one or both of the following parameters—the mass percentage of carbon composite conductive polymer material in the coating layer and the mass percentage of carbon composite conductive polymer material in the composite coated cathode material—within the aforementioned range, it is beneficial to control the coating amount within a more suitable range.

[0022] In some embodiments, in at least a portion of the composite coated cathode material, the coating layer is located on a portion of the surface of the cathode active body.

[0023] By controlling the coating layer to be located on a portion of the surface of the positive electrode active body, that is, by leaving a portion of the surface of the positive electrode active body uncovered, it is beneficial to balance the conductivity of electrons and ions on the surface of the composite coated positive electrode material, better reduce the positive electrode interface impedance, and better improve the cycle performance of solid-state batteries.

[0024] In some embodiments, the coating layer covers 80% to 98% of the surface area of ​​the composite coated cathode material particles.

[0025] In some embodiments, the coating layer covers 85% to 95% of the surface area of ​​the composite coated cathode material particles, and is optionally 85% to 90%.

[0026] By controlling the percentage of the coating layer's coverage area on the particle surface of the composite coated cathode material within the aforementioned range, it is beneficial to better balance the conductivity of electrons and the conductivity of ions on the surface of the composite coated cathode material, thereby improving the cycle performance of solid-state batteries.

[0027] In some embodiments, the conductive polymer satisfies one or more of the following characteristics:

[0028] (a1) The weight-average molecular weight of the conductive polymer is 10 kDa to 3000 kDa;

[0029] (a2) The conductive polymer includes one or more polymers selected from polyaniline, polyacetylene, polypyrrole, polythiophene, polyphenylacetylene, polyphenylene sulfide, polyfuran, polyquinoline and polycarboxylic acid, as well as one or more derivatives of any of the aforementioned polymers; the derivatives are conductive polymers;

[0030] (a3) The conductive polymer has an electronic conductivity at 25°C greater than or equal to 3.5 mS / cm.

[0031] In some embodiments, the conductive polymer satisfies one or more of the following characteristics:

[0032] (a1') The weight-average molecular weight of the conductive polymer is 10kDa to 1000kDa, and can be selected as 50kDa to 200kDa;

[0033] (a2') The conductive polymer includes one or more of polyaniline and polyaniline derivatives;

[0034] (a3') The conductive polymer has an electronic conductivity of 3.5 mS / cm to 1.5 × 10⁻⁶ mS / cm at 25°C. 5 The value can be selected from 4mS / cm to 10000mS / cm.

[0035] By controlling the molecular weight (e.g., weight-average molecular weight) of the conductive polymer within the aforementioned range, it is beneficial to achieve better electrical conductivity, more suitable molecular chain length, and better integration of the conductive polymer with carbon conductive materials. Furthermore, it also enhances the mechanical strength of the conductive polymer, improving the stability of the coating layer and reducing the possibility of damage. Based on these multiple benefits, the composite coating of the cathode material can better suppress volume deformation of the cathode active material and enhance the conductivity of the cathode active layer, thus improving the cycle performance of solid-state batteries.

[0036] By controlling the electronic conductivity of the conductive polymer at 25°C within the aforementioned range, it is beneficial to suppress the volume deformation of the positive electrode active material while also better improving the electronic conductivity.

[0037] In some embodiments, the carbon conductive material satisfies one or more of the following characteristics:

[0038] (b1) The carbon conductive material includes one or more of carbon nanofibers, carbon nanotubes, graphite, carbon black, carbon dots, graphene, Ketjen black and fullerene.

[0039] (b2) The maximum particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected from 2 nm to 0.5 μm; the maximum particle size refers to the maximum diameter among the anisotropic diameters of the particles;

[0040] (b3) The average particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected as 10 nm to 0.5 μm; the average particle size refers to the average of the maximum particle size of each particle;

[0041] (b4) The specific surface area of ​​the carbon conductive material is 1200 m². 2 / g~3000m 2 / g;

[0042] (b5) The electronic conductivity of the carbon conductive material at 25°C is greater than or equal to 10. 5 mS / cm.

[0043] In some embodiments, the carbon conductive material satisfies one or more of the following characteristics:

[0044] (b1') The carbon nanofibers include vapor-grown carbon fibers;

[0045] (b2') The maximum particle size of the carbon conductive material is less than or equal to 0.3 μm, and can be selected as 50 nm to 0.3 μm;

[0046] (b3') The average particle size of the carbon conductive material is less than or equal to 0.3 μm, and can be selected as 50 nm to 0.3 μm;

[0047] (b4') The specific surface area of ​​the carbon conductive material is 1800 m². 2 / g~2300m 2 / g;

[0048] (b5') The electronic conductivity of the carbon conductive material at 25°C is 10. 5 mS / cm~1.5×10 8 mS / cm, selectable as 10 6 mS / cm~10 8 mS / cm.

[0049] By controlling the maximum or average particle size of carbon conductive materials within the aforementioned range, the content of excessively large carbon conductive materials can be reduced, allowing the particle size and distribution of carbon conductive materials to be within a more suitable range. This facilitates better synergistic effects between carbon conductive materials and conductive polymers.

[0050] For carbon composite conductive polymer materials, controlling the maximum or average particle size of the carbon conductive material within the aforementioned range is beneficial for the conductive polymer to be better and more stably composited on the surface of the carbon conductive material, which is conducive to better leveraging the synergistic effect between the carbon conductive material and the conductive polymer. Furthermore, it can also control the particle size and distribution of the carbon composite conductive polymer material within a more suitable range, which is beneficial for improving the coating uniformity and coating stability.

[0051] By controlling the specific surface area of ​​carbon conductive materials within the aforementioned range, it is beneficial to provide a more suitable contact area for conductive polymers, better leverage the excellent electronic conductivity of carbon conductive materials, and better enhance the synergistic effect between carbon conductive materials and conductive polymers.

[0052] By controlling one or more parameters of the maximum particle size, average particle size, and specific surface area of ​​the carbon conductive material within the aforementioned range, it is beneficial to enable the carbon conductive material and the conductive polymer to exert a better synergistic effect, which is beneficial to improve the cycle performance of solid-state batteries.

[0053] In some embodiments, the carbon conductive material in the coating layer has a mass percentage of 0.5% to 10% relative to the conductive polymer.

[0054] In some embodiments, the carbon conductive material in the coating layer has a mass percentage of 0.5% to 5% relative to the conductive polymer, optionally 0.5% to 2.5%.

[0055] By controlling the mass percentage of carbon conductive material relative to conductive polymer in the coating layer within the aforementioned range, it is beneficial to enable the conductive polymer and carbon conductive material to exert a better synergistic effect and improve the cycle performance of solid-state batteries.

[0056] In some embodiments, the composite-coated cathode material satisfies one or more of the following characteristics:

[0057] (c1) The sum of the mass percentages of the carbon conductive material and the conductive polymer in the composite coated cathode material is 0.5% to 10%, and optionally 1% to 5%;

[0058] (c2) The coating layer in the composite coated cathode material has a mass percentage of 0.45% to 10%, and can be selected as 1% to 5%;

[0059] (c3) The average thickness of the coating layer is 5 nm to 150 nm;

[0060] (c4) At least a portion of the coating layer has a thickness of 5 nm to 120 nm;

[0061] (c5) The sum of the mass percentages of the carbon conductive material and the conductive polymer in the coating layer is 90% to 100%;

[0062] (c6) The composite coated cathode material accounts for 80% to 100% of the mass of the cathode active material;

[0063] (c7) The electronic conductivity of the composite coated cathode material at 25°C is greater than or equal to 10 mS / cm.

[0064] In some embodiments, the composite-coated cathode material satisfies one or more of the following characteristics:

[0065] (c1') The sum of the mass percentages of the carbon conductive material and the conductive polymer in the composite coated cathode material is 1% to 3%;

[0066] (c2') The coating layer has a mass percentage of 1% to 3% in the composite coated cathode material;

[0067] (c3') The average thickness of the coating layer is 10nm to 130nm, and can be selected as 20nm to 80nm;

[0068] (c4') At least a portion of the coating layer has a thickness of 10 nm to 120 nm;

[0069] (c5') The sum of the mass percentages of the carbon conductive material and the conductive polymer in the coating layer is 98% to 100%;

[0070] (c6') The composite coated cathode material accounts for 90% to 100% of the mass of the cathode active material.

[0071] By controlling one or more of the following parameters within the aforementioned ranges: the sum of the mass percentages of carbon conductive material and conductive polymer in the composite coated cathode material, the mass percentage of the coating layer in the composite coated cathode material, the average thickness of the coating layer, the sum of the mass percentages of carbon conductive material and conductive polymer in the coating layer, and the mass percentage of the composite coated cathode material in the cathode active material, it is beneficial to control the coating amount within a more suitable range. This is beneficial to suppress the volume deformation of the cathode active material and improve the electron transport capability of the cathode active layer while also better considering the energy density.

[0072] In some embodiments, the mass percentage of the blended conductive agent in the positive electrode active layer is 0-3%; the blended conductive agent refers to different particles located outside the particles of the composite coated positive electrode material.

[0073] In some embodiments, the mass percentage of the blended conductive agent in the positive electrode active layer is 0 to 1.5%.

[0074] By introducing composite coated cathode materials into the cathode active layer, it is beneficial to control the amount of blended conductive agent within a low range, to increase the loading of cathode active material, and to improve energy density while suppressing the volume deformation of cathode active material and enhancing the electron transport capability of cathode active layer.

[0075] In some embodiments, the positive electrode active layer further includes a positive electrode electrolyte material, the positive electrode electrolyte material satisfying one or more of the following characteristics:

[0076] (d1) The Young's modulus of the positive electrode electrolyte material at 25°C is 5 GPa to 100 GPa;

[0077] (d2) The positive electrode electrolyte material includes one or more of the following: sulfide solid electrolyte, halide solid electrolyte, halide oxide solid electrolyte, and polymer electrolyte.

[0078] In some embodiments, the positive electrode electrolyte material satisfies one or more of the following characteristics:

[0079] (d1') The Young's modulus of the positive electrode electrolyte material at 25°C is 10 GPa to 50 GPa;

[0080] (d2') The positive electrode electrolyte material includes sulfide solid electrolytes.

[0081] Positive electrode electrolyte materials with the aforementioned Young's modulus (such as sulfide solid electrolytes) have good flexibility, which is beneficial for improving the solid-solid contact of the positive electrode interface and reducing the interface impedance, thus improving the cycle performance of solid-state batteries.

[0082] In some embodiments, the composite-coated cathode material satisfies one or more of the following characteristics:

[0083] (e1) The positive electrode active body includes one or more of disordered rock salt phase positive electrode materials, spinel phase positive electrode materials and lithium titanate;

[0084] (e2) The positive electrode active body includes one or more of lithium nickel cobalt manganese-based oxides, lithium nickel cobalt aluminum-based oxides, lithium cobalt oxide, chalcogenide positive electrode active materials, lithium manganese oxide, lithium nickel oxide, and lithium-rich manganese-based positive electrode active materials.

[0085] In some embodiments, the composite-coated cathode material satisfies one or more of the following characteristics:

[0086] (e1') The positive electrode active body includes one or more of disordered rock salt phase positive electrode and spinel phase positive electrode;

[0087] (e2') The positive electrode active body includes one or more of lithium nickel cobalt manganese-based oxides, lithium cobalt oxide, and chalcogenide positive electrode active materials.

[0088] Disordered rock salt phase cathode materials, spinel phase cathode materials, and lithium titanate exhibit small volume changes during charge-discharge cycles. By incorporating these cathode active materials into the cathode active body, it is beneficial to improve the solid-solid contact of the cathode interface during charge-discharge cycles.

[0089] By incorporating positive electrode active materials such as lithium nickel cobalt manganese-based oxides, lithium nickel cobalt aluminum-based oxides, lithium cobalt oxide, chalcogenide positive electrode active materials, lithium manganese oxide, lithium nickel oxide, and lithium-rich manganese-based positive electrode active materials into the positive electrode active body, it is beneficial to provide high energy density.

[0090] In some embodiments, the solid-state battery is an all-solid-state battery.

[0091] In some embodiments, the solid-state battery is a lithium-ion secondary battery.

[0092] In some embodiments, the solid-state battery is an all-solid-state lithium-ion secondary battery.

[0093] In a second aspect of this application, a method for preparing a solid-state battery is provided, which can be used to prepare the solid-state battery of the first aspect of this application.

[0094] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps: stacking a positive electrode, a solid electrolyte material layer and a negative electrode in sequence, pressing them together to prepare a solid-state battery;

[0095] The positive electrode sheet includes a positive active layer, which includes a composite coated positive electrode material. The composite coated positive electrode material includes a positive active body and a coating layer located on the surface of the positive active body. The coating layer includes a carbon conductive material and a conductive polymer.

[0096] In some embodiments, the positive electrode active layer includes the features of the positive electrode active layer in the solid-state battery described in the first aspect of this application.

[0097] In some embodiments, the composite-coated cathode material is prepared by a method comprising the following steps:

[0098] A carbon composite conductive polymer material and a positive electrode active bulk material are dry-ball-milled and then heated under a flowing inert atmosphere to prepare the composite-coated positive electrode material. The carbon composite conductive polymer material comprises a polymer matrix formed by the conductive polymer and a carbon conductive substance dispersed within the polymer matrix. The heating temperature is denoted as T1, the glass transition temperature of the conductive polymer is denoted as Tg1, and the thermal decomposition temperature of the conductive polymer is denoted as Td1, satisfying Tg1. <T1<Td1。

[0099] By dry ball milling and mixing the carbon composite conductive polymer material with the positive electrode active body at the aforementioned temperature T1, the conductive polymer in the carbon composite conductive polymer material softens but does not decompose, exhibiting good flexibility, which allows the carbon composite conductive polymer material to be tightly coated on the surface of the positive electrode active body.

[0100] In some embodiments, the method for preparing the solid-state battery satisfies one or more of the following characteristics:

[0101] (f1)Tg1+5℃≤T1≤Td1-5℃;

[0102] (f2) The temperature for the heat treatment is 100℃~200℃;

[0103] (f3) The duration of the heat treatment is 60 min to 360 min;

[0104] (f4) The flowing inert atmosphere includes one or more of argon and nitrogen;

[0105] (f5) The rotation speed for the dry ball milling mixture is 300 rpm to 600 rpm;

[0106] (f6) The ball milling time for the dry ball milling mixture is 12h to 36h;

[0107] (f7) The carbon composite conductive polymer material is prepared by a method comprising the following steps: mixing carbon conductive material raw material and conductive polymer raw material in a dispersion solvent, performing liquid-phase ball milling, and drying to remove the dispersion solvent to obtain the carbon composite conductive polymer material; optionally, the dispersion solvent includes one or more of ethanol, toluene, methanol and diethyl ether; optionally, the rotation speed of the liquid-phase ball milling is 300 rpm to 600 rpm, and the ball milling time is 12 h to 36 h;

[0108] (f8) The positive electrode sheet is prepared by a method comprising the following steps: mixing a positive electrode material composition comprising the composite coated positive electrode material and the positive electrode electrolyte material, and forming a membrane under solvent-free conditions; wherein, the positive electrode material composition may optionally include a binder;

[0109] (f9) The solid-state battery described in the first aspect of this application is prepared.

[0110] By using liquid-phase ball milling, the conductive polymer is dissolved in the dispersion solvent, which allows the carbon conductive material to be more uniformly dispersed in the polymer matrix formed by the conductive polymer.

[0111] Adding heating under a flowing argon atmosphere after heat treatment helps to make the carbon composite conductive polymer material bond more tightly with the positive electrode active body, which is beneficial to further improve the conductivity of the composite coated positive electrode material surface.

[0112] In a third aspect of this application, an electrical device is provided, comprising at least one of the solid-state battery described in the first aspect of this application and a solid-state battery prepared by the method for preparing a solid-state battery described in the second aspect of this application.

[0113] Details of one or more embodiments or examples of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0114] To better describe and illustrate the embodiments, examples, or models 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, examples, or models, 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:

[0115] Figure 1This is a schematic diagram of a solid-state battery cell according to one embodiment of this application.

[0116] Figure 2 for Figure 1 An exploded view of a solid-state battery cell according to an embodiment of this application is shown.

[0117] Figure 3 This is a schematic diagram of a battery device according to one embodiment of this application.

[0118] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0119] Figure 5 for Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown.

[0120] Figure 6 This is a schematic diagram of an electrical device that uses a solid-state battery as a power source according to one embodiment of this application.

[0121] Explanation of reference numerals in the attached figures:

[0122] 1. Battery pack; 2. Upper casing; 3. Lower casing; 4. Battery assembly; 5. Solid-state battery cell; 51. Housing; 52. Solid-state battery cell; 53. Cover plate; 6. Electrical device. Detailed Implementation

[0123] The following describes in detail some embodiments of the solid-state battery, its fabrication method, and its electrical device, with appropriate reference to the accompanying drawings. However, some unnecessary details may be omitted. For example, detailed descriptions of well-known facts and repetitive descriptions of essentially the same 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.

[0124] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be included or excluded independently and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when describing a parameter as an integer ≥ 2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 for that parameter. For instance, when describing a parameter as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0125] In this application, the term "numerical value" includes the number itself and its reasonable approximations. The definition of "numerical value" can apply to discrete numerical points or to the endpoints of a numerical range. Unless otherwise specified, the term "approximation" covers a numerical interval based on a reasonable range of fluctuations of the number itself. This reasonable range of fluctuations can vary depending on the type and magnitude of the number. This reasonable range of fluctuations can be reasonably determined based on the accuracy of the testing or measurement method. Therefore, when referring to a numerical value or a numerical range, unless otherwise specified, it should be understood that the numerical value includes its reasonable approximation, and the numerical range includes reasonable approximations at both endpoints. Those skilled in the art will understand that acceptable fluctuation ranges of the relevant approximations can be included within the definition of the numerical value or the numerical range. In this application, unless otherwise specified, "N1" can be reasonably understood as "about N1," and "N1~N2" can be reasonably understood as "about N1 to about N2," where N1 and N2 are two unequal numerical values.

[0126] In this application, unless otherwise specified, "about" means within a reasonable range above and below the stated number, and the range of fluctuation may vary depending on the type and value of the stated number. For example, a range of ±10%, ±5%, ±2%, ±1%, etc., may be allowed. For example, taking "about 20°C" and its approximation as ±1°C, approximate values ​​such as 19°C, 19.5°C, etc., within the approximation range indicated by "about 20°C" should also be included in the range indicated by "about 20°C".

[0127] 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.

[0128] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0129] 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.

[0130] Those skilled in the art will understand that, unless otherwise specified, the order in which the steps are written in the various embodiments or methods of this application 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, but are preferably performed sequentially. For example, if method M 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, method M may also include step (c), meaning that step (c) can be added to method M in any order. For example, method M 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.

[0131] 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, if 'a' includes a1, a2, and a3, it may also include other members or exclude additional members unless otherwise specified. This can be considered as providing both features or solutions where "a consists of a1, a2, and a3" or "a is selected from a1, a2, and a3," and features or solutions where "a includes not only a1, a2, and a3, but also other members."

[0132] In this application, unless otherwise specified, M (e.g., m1) means that m1 is a non-limiting example of M, and it is understood that M is not limited to m1.

[0133] 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."

[0134] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. Any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "M and / or N" represents the group consisting of M, N, and "a combination of M and N". "Containing M and / or N" can mean "containing M, containing N, and containing both M and N", or "containing M, containing N, or containing both M and N", and can be appropriately understood according to the context.

[0135] 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.

[0136] 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.

[0137] In this document, terms such as "preferred," "better," "more suitable," "ideal," "good," and "superior" are merely descriptions of more effective implementation methods or embodiments, and should be understood not to limit the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0138] In this application, terms such as "further," "even more," "especially," "for example," "as," "example," and "exemplary" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0139] In this application, the terms "first aspect," "second aspect," "third aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0140] In this application, unless otherwise expressly specified and limited, the phrase "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In this application, unless otherwise expressly specified and limited, the phrase "above" or "below" the second feature can indicate a horizontal positional relationship, or it can simply indicate the existence of an attachment relationship without specifying a horizontal positional relationship.

[0141] In this application, the term "room temperature" generally refers to 4℃ to 35℃, and may refer to 20℃ ± 5℃. In some embodiments or examples of this application, room temperature refers to 20℃ to 30℃.

[0142] In this application, if the unit for a data range is only followed by the right endpoint, it indicates that the units for the left and right endpoints are the same. For example, 3~5h or 3-5h both mean that the unit for the left endpoint "3" and the right endpoint "5" is h (hours), and both have the same meaning as 3h~5h. Furthermore, similar descriptions of other parameters such as temperature and size are interpreted in the same way.

[0143] In this application, the exemplary descriptions such as "in some implementations (or embodiments)" and "in one implementation (or embodiment)" may cover, but are not limited to, the following meanings: these solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0144] Unless otherwise stated, the improvements described in this application are not intended to be limited to any theoretical constraints.

[0145] For any test method for a certain parameter described in this application, as long as the test result of at least one test method is within the described range, it can be included in the protection scope of this application.

[0146] Solid-state batteries do not use a traditional liquid electrolyte. The component particles in a solid-solid contact system rely heavily on this interfacial contact for active ion transport. However, voids inevitably exist between the component particles in solid-state batteries, which can hinder interfacial charge transport. This solid-solid interface problem limits the performance of solid-state batteries, leading to issues such as poor cycle stability. During charge-discharge cycles, reversible extraction and insertion of active ions occur at the positive electrode, causing volume changes in the positive electrode active material and potentially affecting the stability of the solid-solid interface within the positive electrode layer. When active ions are extracted, the voids at the positive electrode interface further expand, increasing battery impedance and impacting the capacity and cycle stability of the solid-state battery.

[0147] According to various embodiments and examples of this application, this application provides a solid-state battery, a method for preparing the same, and an electrical device thereof. This solid-state battery exhibits significantly improved cycle performance.

[0148] In some embodiments, a solid-state battery is provided, comprising a positive electrode layer, a positive electrode active layer, and a composite-coated positive electrode material. The composite-coated positive electrode material includes a positive electrode active body and a coating layer located on the surface of the positive electrode active body. The coating layer includes a carbon conductive material and a conductive polymer. This solid-state battery exhibits significantly improved cycle performance.

[0149] In some embodiments, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0150] In this application, "layered arrangement" refers to the description of the stacking direction between layered structures. For example, "including structural layer A and structural layer B in a layered arrangement" means that the stacking direction of structural layer A and structural layer B is along their respective layer thickness directions, that is, the thickness direction of structural layer A and the thickness direction of structural layer B are the same or substantially the same.

[0151] Unless otherwise specified, the term "solid-state battery" in this application refers to a battery in which the electrolyte includes a solid electrolyte material. 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 found in traditional liquid lithium-ion batteries. Solid-state batteries are better suited for high-energy-density positive and negative electrode materials and reduce system weight, which is beneficial for achieving both increased energy density and improved performance.

[0152] In this application, unless otherwise specified, "solid electrolyte material" refers to an electrolyte material or electrolyte substance that exists in solid form during the storage and fabrication of solid-state batteries and components constituting solid-state batteries, as well as during the operation of solid-state batteries. It is understood that this includes, but is not limited to, solid electrolyte materials existing in solid form at room temperature.

[0153] In this application, unless otherwise specified, "electrode layer" includes electrode active material. The electrode layer can be a positive electrode layer or a negative electrode layer. "Electrode active material" in the electrode layer refers to a material capable of reversibly inserting and extracting active ions. Unless otherwise specified, "negative electrode active material" refers to a material used in the negative electrode layer capable of reversibly inserting and extracting active ions; "positive electrode active material" refers to a material used in the positive electrode layer capable of reversibly extracting and inserting active ions. During solid-state battery charging, active ions are extracted from the positive electrode, pass through the solid electrolyte layer, and insert into the negative electrode; 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; non-limitingly, the active ions can be lithium ions, corresponding to a lithium-ion solid-state battery.

[0154] In this application, unless otherwise specified, "electrode active layer" includes at least one of the positive active layer in the positive electrode layer and the negative active layer in the negative electrode layer. Depending on the specific circumstances, the electrode active layer may refer to either the positive active layer or the negative active layer. It is understood that the positive active layer includes the positive active material and may also be referred to as the "positive active material layer"; the negative active layer includes the negative active material and may also be referred to as the "negative active material layer".

[0155] In a first aspect, this application provides a solid-state battery comprising a positive electrode layer, the positive electrode layer including a positive electrode active layer, the positive electrode active layer including a composite coated positive electrode material, the composite coated positive electrode material including a positive electrode active body and a coating layer located on the surface of the positive electrode active body, the coating layer including a carbon conductive material and a conductive polymer. This solid-state battery exhibits significantly improved cycle performance.

[0156] In some embodiments, a solid-state battery is provided, comprising a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially. The positive electrode layer includes a positive electrode active layer, which includes a positive electrode active material. The positive electrode active material includes a composite coated positive electrode material, which includes a positive electrode active body and a coating layer located on the surface of the positive electrode active body. The coating layer includes a carbon conductive material and a conductive polymer.

[0157] Unless otherwise stated in this application, "composite coated cathode material" includes a cathode active body and a coating layer located on the surface of the cathode active body, the coating layer including carbon conductive material and conductive polymer.

[0158] In this application, unless otherwise specified, "carbon conductive material" refers to a carbon material capable of transporting electrons. Carbon conductive materials may include, but are not limited to, traditional carbon conductive agents, and may also include carbon materials with good electronic conductivity, such as graphite. "Carbon material" refers to a substance based on the element carbon.

[0159] In this application, unless otherwise specified, "conductive polymer" has the common meaning in the art and may include conductive polymers known in the art as being usable as conductive materials in batteries.

[0160] A composite coated cathode material is introduced into the cathode layer. A coating layer consisting of a carbon conductive material and a conductive polymer is formed on the surface of the cathode active body. The conductive polymer is a soft polymer material with high electronic conductivity, while the carbon conductive material has excellent electron transport capabilities. On the one hand, the flexibility of the conductive polymer allows it to directly and tightly contact the cathode active body, thereby effectively suppressing the volume deformation of the cathode active material using the viscoelasticity of the conductive polymer. On the other hand, the high electronic conductivity of the conductive polymer and the excellent electron transport capabilities of the carbon conductive material can be combined to enhance the electron conduction between the cathode active material and other cathode components. Not wanting to be limited by any theory, by introducing a composite coated cathode material into the cathode layer, the solid-solid contact stability of the cathode interface in solid-state batteries can be significantly improved, and the electron conduction capability of the cathode layer can be enhanced. Therefore, the capacity utilization of the cathode and the cycle stability of the solid-state battery can be significantly improved, thus significantly enhancing the cycle performance of the solid-state battery.

[0161] By improving the solid-solid contact stability of the positive electrode interface and enhancing the electronic conductivity of the positive electrode layer, the impedance of the positive electrode interface can be reduced, thereby reducing the internal resistance of the battery.

[0162] In this application, particle structure analysis methods such as transmission electron microscopy (TEM) can be used to detect and analyze whether the positive electrode active material has a coating layer. For example, instruments such as high-resolution transmission electron microscopy (HR TEM, such as Thermo Scientific-Talos F200S G2) can be used. Elemental analysis methods such as energy dispersive spectroscopy (EDS or EDX), X-ray diffraction (XRD), and inductively coupled plasma spectrometry (ICP) can also be used to detect and identify the elemental types and chemical composition of the positive electrode active material and the coating layer. These methods can also be used to analyze parameters such as the thickness of the coating layer, the proportion of the coating layer in the coated particles (such as composite coated positive electrode materials), and the degree of coating of the coating layer on the surface of the coated particles.

[0163] For composite-coated cathode materials, particle cross-sections can be obtained by particle cutting using methods such as FIB (Focused Ion Beam) and then observed under HRTEM (High Resolution Transmission Electron Microscopy). A clear boundary can be observed at the coating interface. Based on the HRTEM images, the average thickness (D1) of the coating layer and the percentage of the coating layer's coverage area on the particle surface of the composite-coated cathode material can be analyzed and calculated. A Parameters such as ) can be further analyzed by combining one or more methods, such as energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectrometry (ICP), to confirm the types and content parameters of substances in the coating layer and the positive electrode active body. For example, the number of statistical locations used in the statistical analysis of the average thickness of the coating layer can be ≥3, and optionally ≥5. Statistical F A At that time, the number of particles of the composite coated cathode material can be ≥4, or optionally ≥8.

[0164] Solid-state batteries can be disassembled, and the solid materials in the positive electrode active layer can be extracted for particle structure analysis and / or elemental analysis, such as TEM.

[0165] For the conductive polymer in the coating layer of the composite coated cathode material, the following method can be used to obtain the test sample: Soak the test sample of the composite coated cathode material in an organic solvent (such as acetone, methanol, chloroform, dihydrofuran, etc.) to dissolve the conductive polymer in the organic solvent. Centrifuge, collect the liquid phase, and obtain a solution containing the conductive polymer. This solution can be prepared as a liquid test sample or dried into a solid sample for detection.

[0166] Non-limiting, the type, structure, and molecular weight of conductive polymer components can be analyzed using one or more of the following methods: Fourier transform infrared (FT-IR) spectroscopy, ultraviolet spectroscopy, and proton nuclear magnetic resonance (NMR) spectroscopy. 1 Methods include ¹H NMR, gel permeation chromatography (GPC), high performance liquid chromatography (HPLC), mass spectrometry, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The sample preparation and testing methods for these methods are known to those skilled in the art, and the test parameters can be appropriately adjusted according to the sample characteristics.

[0167] In some embodiments, at least a portion of the carbon conductive material and the conductive polymer are present as a carbon composite conductive polymer material; in the carbon composite conductive polymer material, the carbon conductive material is dispersed in a polymer matrix formed by the conductive polymer.

[0168] By incorporating a carbon composite conductive polymer material into the coating layer of the composite-coated cathode material, the carbon conductive material and the conductive polymer exist in a composite manner. This allows for a better synergistic effect between the conductive polymer and the carbon conductive material. On one hand, it facilitates more and better close contact between the conductive polymer and the surface of the cathode active material, thereby better suppressing the volume deformation of the cathode active material. On the other hand, it improves the uniformity of the conductivity on the surface of the cathode active material, allowing active ions to be more uniformly embedded at different sites on the cathode active material, reducing local stress concentration caused by differences in active ion embedding rates, and improving the structural stability of the cathode active material. Furthermore, the close composite between the carbon conductive material and the conductive polymer inhibits or prevents the carbon conductive material from detaching from the surface of the cathode active material, improving the compositional stability of the coating layer, and thus improving the conductivity stability of the carbon composite conductive polymer material surface. Based on the synergistic effect of the aforementioned multiple actions, the capacity utilization and cycle performance of solid-state batteries can be better improved.

[0169] In some embodiments, the carbon composite conductive polymer material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0170] (t1) In carbon composite conductive polymer materials, the mass percentage of carbon conductive material relative to the conductive polymer (R) 10The percentage can be 0.5% to 10%, optionally 0.5% to 5%, further optionally 0.5% to 2.5%, or any of the following percentages or a range composed of any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, etc.

[0171] (t2) Mass percentage of carbon composite conductive polymer material in the coating layer (F) 11 It can be 80% to 100%, optionally 90% to 100%, or any of the following percentages or a range composed of any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 100%, etc.

[0172] (t3) Mass percentage of carbon composite conductive polymer material in composite coated cathode material (F) 10 The percentage can be 0.45% to 10%, or 1% to 5%, or any of the following percentages or a range consisting of any two of the following percentages: 0.45%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, etc.

[0173] In some embodiments, the carbon composite conductive polymer material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0174] (t1') In carbon composite conductive polymer materials, the mass percentage of carbon conductive material relative to conductive polymer is 0.5% to 5%, and can be selected as 0.5% to 2.5%;

[0175] (t2') The mass percentage of carbon composite conductive polymer material in the coating layer is 90% to 100%;

[0176] (t3') The mass percentage of carbon composite conductive polymer material in the composite coated cathode material is 1% to 3%.

[0177] By controlling the mass percentage (R) of carbon conductive material relative to conductive polymer in carbon composite conductive polymer materials... 10Within the aforementioned range, it is beneficial to achieve better and more stable composite between conductive polymers and carbon conductive materials, better leverage the synergistic effect between conductive polymers and carbon conductive materials, and better improve the cycle performance of solid-state batteries.

[0178] By controlling the mass percentage (F) of the carbon composite conductive polymer material in the coating layer 11 The mass percentage of carbon composite conductive polymer material in the composite coated cathode material (F) 10 Having one or two of the parameters in the above-mentioned range is beneficial for controlling the coating amount within a more suitable range.

[0179] In some embodiments, in the composite coated cathode material, the coating layer is located on a portion of the surface of the cathode active body.

[0180] In some embodiments, in at least a portion of the composite coated cathode material, the coating layer is located on a portion of the surface of the cathode active body.

[0181] By controlling the coating layer to be located on a portion of the surface of the positive electrode active body, that is, by leaving a portion of the surface of the positive electrode active body uncovered, it is beneficial to balance the conductivity of electrons and ions on the surface of the composite coated positive electrode material, better reduce the positive electrode interface impedance, and better improve the cycle performance of solid-state batteries.

[0182] In some embodiments, the percentage of the area covered by the coating layer on the particle surface of the composite coated cathode material (F) A The percentage can be 80%–98%, 85%–95%, or further selected as 85%–90%. It can also be any of the following percentages or a range composed of any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 97%, 98%, etc.

[0183] In some embodiments, the coating layer covers 85% to 90% of the surface area of ​​the composite coated cathode material particles.

[0184] By measuring the percentage of the coating area (F) on the particle surface of the composite coated cathode material. A Controlling the parameters within the aforementioned range helps to better balance the conductivity of electrons and ions on the surface of the composite-coated cathode material, thereby improving the cycle performance of solid-state batteries.

[0185] In some embodiments, the mass percentage (F) of the coating layer in the composite coated cathode material MThe percentage can be 1% to 5%, or any of the following percentages or a range consisting of any two of the following percentages: 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. See also the context of this application.

[0186] In some implementations, F A The percentage of the coating layer in the composite coated cathode material is 80% (F). M The figure is 1%.

[0187] In other implementations, F A 95%, F M It is 5%.

[0188] In some embodiments, the conductive polymer satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0189] (a1) The weight-average molecular weight of the conductive polymer is 10 kDa to 3000 kDa, preferably 10 kDa to 1000 kDa, further preferably 10 kDa to 500 kDa, and even more preferably 50 kDa to 200 kDa. It can also be any of the following molecular weights or a range selected from any two of the following molecular weights: 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 60 kDa, 70 kDa, 80 kDa, 90 kDa, 100 kDa. Da, 120kDa, 150kDa, 160kDa, 180kDa, 200kDa, 250kDa, 300kDa, 350kDa, 400kDa, 450kDa, 500kDa, 600kDa, 700kDa, 800k Da, 900kDa, 1000kDa, 1200kDa, 1500kDa, 1600kDa, 1800kDa, 2000kDa, 2400kDa, 2500kDa, 2600kDa, 2800kDa, 3000kDa, etc.;

[0190] (a2) Conductive polymers include one or more polymers selected from polyaniline, polyacetylene, polypyrrole, polythiophene, polyphenylacetylene, polyphenylene sulfide, polyfuran, polyquinoline and polycarboxylic acid, as well as one or more derivatives of any of the aforementioned polymers; any derivative of any polymer is a conductive polymer.

[0191] (a3) The conductive polymer has an electronic conductivity at 25°C greater than or equal to 3.5 mS / cm, and can be selected from 3.5 mS / cm to 1.5 × 10⁻⁶ mS / cm. 5The conductivity can be further selected from 4 mS / cm to 10000 mS / cm, and even more specifically from 10 mS / cm to 10000 mS / cm. It can also be greater than or equal to any of the following conductivity values, or selected from the range consisting of any of the following conductivity values ​​and 10000 mS / cm, or selected from the range consisting of any two of the following conductivity values: 3.5 mS / cm, 4 mS / cm, 5 mS / cm, 6 mS / cm, 7 mS / cm, 8 mS / cm, 9 mS / cm, 10 mS / cm, 15 mS / cm, 20 mS / cm, 30 mS / cm, 40 mS / cm, 50 mS / cm, 60 mS / cm, 70 mS / cm, 80 mS / cm, 100 mS / cm. cm, 150mS / cm, 200mS / cm, 250mS / cm, 300mS / cm, 400mS / cm, 500mS / cm, 600mS / cm, 800mS / cm, 1000mS / cm, 1100mS / cm, 1200mS / cm, 1300mS / cm, 1400mS / c m, 1500mS / cm, 1600mS / cm, 1800mS / cm, 2000mS / cm, 2500mS / cm, 3000mS / cm, 4000mS / cm, 5000mS / cm, 6000mS / cm, 7000mS / cm, 8000mS / cm, 9000mS / cm, 10 4 mS / cm, 1.2×10 4 mS / cm, 1.5×10 4 mS / cm, 1.6×10 4 mS / cm, 1.8×10 4 mS / cm, 2×10 4 mS / cm, 3×10 4 mS / cm, 4×10 4 mS / cm, 5×10 4 mS / cm, 6×10 4 mS / cm, 7×10 4 mS / cm, 8×10 4 mS / cm, 9×10 4 mS / cm, 10 5 mS / cm, 1.2×10 5 mS / cm, 1.5×10 5 mS / cm, etc.

[0192] In some embodiments, the conductive polymer satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0193] (a1') The weight-average molecular weight of the conductive polymer is 10kDa to 1000kDa, and can be selected as 50kDa to 200kDa;

[0194] (a2') The conductive polymer includes one or more of polyaniline and derivatives of polyaniline;

[0195] (a3') The electronic conductivity of the conductive polymer at 25℃ is 3.5 mS / cm~1.5×10⁻⁶. 5 The value of mS / cm can be selected from 4mS / cm to 10000mS / cm, and further selected from 10mS / cm to 10000mS / cm.

[0196] In this application, the terms "molecular weight," "average molecular weight," "weight-average molecular weight," or "number-average molecular weight" for polymers, unless otherwise specified, refer to molecular mass measured in Daltons (Da), where 1 Dalton equals... 12 One-twelfth the mass of a carbon atom. 1 kDa = 1000 Da.

[0197] The weight-average molecular weight and number-average molecular weight of conductive polymers can be determined using gel permeation chromatography (GPC). A GPC-100 instrument can be used. Tetrahydrofuran can be used as the test solvent.

[0198] In this application, "electronic conductivity" has a well-known meaning in the art and can be used to characterize the strength of a material's ability to transport electrons; the higher the electronic conductivity, the stronger the electron conduction ability. Electronic conductivity can be expressed as σ. The electronic conductivity of materials can be tested using methods and instruments already available in the art. Unless otherwise specified, the test temperature is 25°C.

[0199] Electronic conductivity can be tested as follows: The solid powder of the material to be tested is placed in a test mold, with stainless steel gaskets used as blocking electrodes on both sides, and pressed into a conductivity model battery. Electronic conductivity can be obtained by constant-voltage DC testing of the model battery using an electrochemical workstation; the electronic conductivity σ is calculated using the following formula: σ = d / (R × S), where R represents the electrochemical impedance (the electronic impedance value is measured by the electrochemical workstation), d is the length along the current conduction direction (corresponding to the thickness of the film structure), and S is the cross-sectional area perpendicular to the current conduction direction (corresponding to the effective area).

[0200] For conductive polymers, the following method can be used to prepare test samples when testing electronic conductivity: Take 150 mg of conductive polymer, press it into a cylinder with a diameter of 10 mm in a mold with a pressure of 200 MPa, and perform AC impedance spectroscopy (EIS) test while maintaining the pressure.

[0201] By controlling the molecular weight (e.g., weight-average molecular weight) of the conductive polymer within the aforementioned range, it is beneficial to achieve better electrical conductivity, more suitable molecular chain length, and better integration of the conductive polymer with carbon conductive materials. Furthermore, it also enhances the mechanical strength of the conductive polymer, improving the stability of the coating layer and reducing the possibility of damage. Based on these multiple benefits, the composite coating of the cathode material can better suppress volume deformation of the cathode active material and enhance the conductivity of the cathode active layer, thus improving the cycle performance of solid-state batteries.

[0202] By controlling the electronic conductivity of the conductive polymer at 25°C within the aforementioned range, it is beneficial to suppress the volume deformation of the positive electrode active material while also better improving the electronic conductivity.

[0203] In some embodiments, the carbon conductive material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0204] (b1) Carbon conductive materials include one or more of carbon nanofibers, carbon nanotubes, graphite, carbon black, carbon dots, graphene, Ketjen black and fullerene; optionally, carbon nanofibers include vapor-grown carbon fibers (VGCF).

[0205] (b2) The maximum particle size of the carbon conductive material can be less than or equal to 0.5 μm, optionally 2 nm to 0.5 μm, further optionally 10 nm to 0.5 μm, or less than or equal to 0.3 μm, optionally 50 nm to 0.3 μm, or any of the following values ​​or a range selected from any two of the following values: 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 25 nm, 26 nm, 28 nm, 30 nm, 32 nm, 34 nm, 35 nm, 36 nm, 38 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 120 nm, 140 nm, 1 The particle sizes are 50nm, 160nm, 180nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 700nm, 800nm, 900nm, 0.1μm, 0.11μm, 0.12μm, 0.13μm, 0.14μm, 0.15μm, 0.16μm, 0.18μm, 0.2μm, 0.22μm, 0.24μm, 0.25μm, 0.26μm, 0.28μm, 0.3μm, 0.35μm, 0.4μm, 0.45μm, 0.5μm, etc.; the maximum particle size refers to the largest diameter among the anisotropic diameters of the particles; optionally, carbon nanofibers include vapor-grown carbon fibers (VGCF);

[0206] (b3) The average particle size of the carbon conductive material can be less than or equal to 0.5 μm, optionally ranging from 10 nm to 0.5 μm, or less than or equal to 0.3 μm, optionally ranging from 50 nm to 0.3 μm, or any of the following values ​​or a range consisting of any two of the following values: 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 25 nm, 26 nm, 28 nm, 30 nm, 32 nm, 34 nm, 35 nm, 36 nm, 38 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm. The range of particle sizes is as follows: nm, 180nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 700nm, 800nm, 900nm, 0.1μm, 0.11μm, 0.12μm, 0.13μm, 0.14μm, 0.15μm, 0.16μm, 0.18μm, 0.2μm, 0.22μm, 0.24μm, 0.25μm, 0.26μm, 0.28μm, 0.3μm, 0.35μm, 0.4μm, 0.45μm, 0.5μm, etc.; the average particle size refers to the average of the maximum particle size of each particle; optionally, carbon nanofibers include vapor-grown carbon fibers (VGCF);

[0207] (b4) The specific surface area of ​​carbon conductive material is 1200 m². 2 / g~3000m 2 / g, optional 1500m 2 / g~2500m 2 / g, further optional to 1800m 2 / g~2300m 2 / g, can also be any of the following values ​​or a range selected from any two of the following values: 1200m 2 / g、1300m 2 / g, 1400m 2 / g, 1500m 2 / g, 1600m 2 / g、1700m 2 / g、1800m 2 / g、1900m 2 / g、2000m 2 / g、2100m 2 / g、2200m 2 / g、2300m 2 / g、2400m 2 / g、2500m 2 / g、2600m 2 / g、2700m 2 / g、2800m 2 / g、3000m 2 / g, etc.; optionally, carbon nanofibers include vapor-grown carbon fibers (VGCF);

[0208] (b5) The electronic conductivity of carbon conductive materials at 25°C is greater than or equal to 10. 5 mS / cm, 10 optional 5 mS / cm~1.5×10 8 mS / cm, further selectable as 10 6 mS / cm~10 8 mS / cm, or greater than or equal to any of the following conductivity values, or selected from any of the following conductivity values ​​and 10 7 The range defined by mS / cm, or the range selected from any two of the following conductivity values: 10 5 mS / cm, 1.5×10 5 mS / cm, 2×10 5 mS / cm, 3×10 5 mS / cm, 4×10 5 mS / cm, 5×10 5 mS / cm, 6×10 5 mS / cm, 8×10 5 mS / cm, 1×10 6 mS / cm, 1.1×10 6 mS / cm, 1.2×10 6 mS / cm, 1.3×10 6 mS / cm, 1.4×10 6 mS / cm, 1.5×10 6 mS / cm, 1.6×10 6 mS / cm, 1.8×10 6 mS / cm, 2×10 6 mS / cm, 2.2×10 6 mS / cm, 2.4×10 6 mS / cm, 2.5×10 6 mS / cm, 2.6×10 6 mS / cm, 2.8×10 6 mS / cm, 3×10 6 mS / cm, 3.5×10 6 mS / cm, 4×10 6 mS / cm, 4.5×10 6 mS / cm, 5×10 6mS / cm, 6×10 6 mS / cm, 7×10 6 mS / cm, 8×10 6 mS / cm, 9×10 6 mS / cm, 9.5×10 6 mS / cm, 1×10 7 mS / cm, 1.5×10 7 mS / cm, 2×10 7 mS / cm, 3×10 7 mS / cm, 4×10 7 mS / cm, 5×10 7 mS / cm, 6×10 7 mS / cm, 7×10 7 mS / cm, 8×10 7 mS / cm, 10 8 mS / cm, 1.2×10 8 mS / cm, 1.5×10 8 mS / cm, etc.

[0209] In some embodiments, the carbon conductive material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0210] (b1') Carbon nanofibers include vapor-grown carbon fibers (VGCF);

[0211] (b2') The maximum particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected from 50 nm to 0.3 μm. It can also be any of the following values ​​or a range selected from any two of the following values: 50 nm, 55 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm, 180 nm, 200 nm, 250 nm, 300 nm, 350 nm. nm, 400nm, 450nm, 500nm, 550nm, 600nm, 700nm, 800nm, 900nm, 0.1μm, 0.11μm, 0.12μm, 0.13μm , 0.14μm, 0.15μm, 0.16μm, 0.18μm, 0.2μm, 0.22μm, 0.24μm, 0.25μm, 0.26μm, 0.28μm, 0.3μm, etc.;

[0212] (b3') The average particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected from 50 nm to 0.3 μm. It can also be any of the following values ​​or a range selected from any two of the following values: 50 nm, 55 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm, 180 nm, 200 nm, 250 nm, 300 nm, 350 nm. nm, 400nm, 450nm, 500nm, 550nm, 600nm, 700nm, 800nm, 900nm, 0.1μm, 0.11μm, 0.12μm, 0.13μm , 0.14μm, 0.15μm, 0.16μm, 0.18μm, 0.2μm, 0.22μm, 0.24μm, 0.25μm, 0.26μm, 0.28μm, 0.3μm, etc.;

[0213] (b4') The specific surface area of ​​the carbon conductive material is 1800 m². 2 / g~2300m 2 / g, can also be any of the following values ​​or a range selected from any two of the following values: 1800m 2 / g、1900m 2 / g、2000m 2 / g、2100m 2 / g、2200m 2 / g、2300m 2 / g etc.;

[0214] (b5') The electronic conductivity of carbon conductive materials at 25°C is 10. 5 mS / cm~1.5×10 8 mS / cm, selectable as 10 6 mS / cm~10 8 mS / cm, further selectable as 10 6 mS / cm~10 7 mS / cm.

[0215] In this application, the "maximum particle size of carbon conductive material" can be obtained from the solid-state battery by the following method: disassemble the solid-state battery cell, extract the positive electrode layer, perform SEM (instrument model: Phenom-XL G2) electrode testing, and find the carbon conductive material in the field of view based on the EDS joint scanning results, and measure its diameter.

[0216] For example, the maximum particle size of carbon conductive materials can be tested using the following method: The powder sample of the carbon conductive material to be tested is adhered to a conductive adhesive and subjected to scanning electron microscopy (SEM) at a magnification of 500X to 30KX. The maximum particle size in each direction of diameter of the selected particles in the SEM image is recorded as the "maximum particle size". At least 5 particles can be selected for statistical analysis. The distribution range of the maximum particle size of the statistically analyzed particles is recorded. Scanning electron microscopy (SEM) instruments such as ZEISS Sigma300, JEOL, and Axia ChemiSEM can be used. The average of the "maximum particle sizes" of multiple particles is taken to obtain the "average particle size" of the material to be tested. The number of particles counted can be at least 6, optionally at least 10, but is not limited to these. For carbon conductive materials with carbon nanotube-like shapes, the maximum diameter can be determined by the maximum outer diameter.

[0217] In this application, unless otherwise specified, the term "specific surface area" has the meaning known in the art. It can be tested using nitrogen adsorption specific surface area analysis and calculated using the BET (Brunauer Emmett Teller) method. Nitrogen adsorption specific surface area analysis can be performed using a Tri Star II 3020 specific surface area and porosity analyzer from Micromeritics, USA. The test procedures can refer to GB / T 19587-2004. Detailed steps are as follows: The sample to be tested is dried in a vacuum drying oven; then, using nitrogen as the adsorbed gas, adsorption-desorption curves with a relative pressure P / P0 of 0–0.99 are plotted using a specific surface area and porosity analyzer, where P is the equilibrium adsorption pressure and P0 is the saturated vapor pressure. The specific surface area of ​​the material is calculated using the BET method.

[0218] By controlling the maximum or average particle size of carbon conductive materials within the aforementioned range, the content of excessively large carbon conductive materials can be reduced, allowing the particle size and distribution of carbon conductive materials to be within a more suitable range. This facilitates better synergistic effects between carbon conductive materials and conductive polymers.

[0219] For carbon composite conductive polymer materials, controlling the maximum or average particle size of the carbon conductive material within the aforementioned range is beneficial for the conductive polymer to be better and more stably composited on the surface of the carbon conductive material, which is conducive to better leveraging the synergistic effect between the carbon conductive material and the conductive polymer. Furthermore, it can also control the particle size and distribution of the carbon composite conductive polymer material within a more suitable range, which is beneficial for improving the coating uniformity and coating stability.

[0220] By controlling the specific surface area of ​​carbon conductive materials within the aforementioned range, it is beneficial to provide a more suitable contact area for conductive polymers, better leverage the excellent electronic conductivity of carbon conductive materials, and better enhance the synergistic effect between carbon conductive materials and conductive polymers.

[0221] By controlling one or more parameters of the maximum particle size, average particle size, and specific surface area of ​​the carbon conductive material within the aforementioned range, it is beneficial to enable the carbon conductive material and the conductive polymer to exert a better synergistic effect, which is beneficial to improve the cycle performance of solid-state batteries.

[0222] In some embodiments, the carbon conductive material in the coating layer has a mass percentage of 0.5% to 10% relative to the conductive polymer, optionally 0.5% to 5%, further optionally 0.5% to 2.5%, and may also be any of the following percentages or a range selected from any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, etc.

[0223] In some embodiments, the carbon conductive material in the coating layer has a mass percentage of 0.5% to 5% relative to the conductive polymer, optionally 0.5% to 5%, optionally 0.5% to 2.5%, and may also be any of the following percentages or a range selected from any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0224] By controlling the mass percentage (R) of carbon conductive material relative to conductive polymer in the coating layer 11 Within the aforementioned range, it is beneficial to enable the conductive polymer and carbon conductive material to better exert synergistic effects and improve the cycle performance of solid-state batteries.

[0225] In some implementations, the composite-coated cathode material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0226] (c1) The sum of the mass percentages of carbon conductive material and conductive polymer in the composite coated cathode material is 0.5% to 10%, optionally 1% to 5%, and may also be any of the following percentages or a range selected from any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, etc.

[0227] (c2) Mass percentage of the coating layer in the composite coated cathode material (F) M The percentage can be 0.45% to 10%, optionally 1% to 5%, optionally 0.5% to 5%, further optionally 0.5% to 2.5%, or any of the following percentages or a range selected from any two of the following percentages: 0.45%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, etc.

[0228] (c3) The average thickness (D1) of the coating layer can be 5nm to 150nm, optionally 10nm to 130nm, further optionally 20nm to 80nm, or any of the following values ​​or a range selected from any two of the following values: 5nm, 6nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, etc.

[0229] (c4) The thickness of at least a portion of the coating layer is 5nm to 120nm, optionally 10nm to 120nm, and may also be any of the following values ​​or a range selected from any two of the following values: 5nm, 6nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, etc.

[0230] (c5) The sum of the mass percentages of carbon conductive material and conductive polymer in the coating layer (F) 21 It can be 90% to 100%, optionally 98% to 100%, or any of the following percentages or a range composed of any two of the following percentages: 90%, 92%, 94%, 95%, 96%, 98%, 100%, etc.

[0231] (c6) Mass percentage of composite-coated cathode material in cathode active material (F) C It can be 80% to 100%, optionally 90% to 100%, or any of the following percentages or a range composed of any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, etc.

[0232] (c7) The electronic conductivity of the composite-coated positive electrode material at 25℃ is greater than or equal to 10 mS / cm, and may also be greater than or equal to any of the following conductivity values, or selected from any two of the following conductivity values: 10 mS / cm, 15 mS / cm, 20 mS / cm, 30 mS / cm, 40 mS / cm, 50 mS / cm, 60 mS / cm, 70 mS / cm, 80 mS / cm, 100 mS / cm, 150 mS / cm, 200 mS / cm, 250 mS / cm, 300 mS / cm, 400 mS / cm, 500 mS / cm. m, 600mS / cm, 800mS / cm, 1000mS / cm, 1100mS / cm, 1200mS / cm, 1300mS / cm, 1400mS / cm, 1500mS / cm, 1600mS / cm, 1800mS / cm, 2 000mS / cm, 2500mS / cm, 3000mS / cm, 4000mS / cm, 5000mS / cm, 6000mS / cm, 7000mS / cm, 8000mS / cm, 9000mS / cm, 10000mS / cm, etc.

[0233] In some implementations, the composite-coated cathode material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0234] (c1') The sum of the mass percentages of carbon conductive material and conductive polymer in the composite coated cathode material is 1% to 3%;

[0235] (c2') The mass percentage of the coating layer in the composite coated cathode material is 1% to 3%;

[0236] The average thickness of the (c3') coating layer is 10 nm to 30 nm.

[0237] (c4') At least a portion of the coating layer has a thickness of 5 nm to 15 nm;

[0238] (c5') The sum of the mass percentages of carbon conductive material and conductive polymer in the coating layer is 98% to 100%;

[0239] (c6') The composite-coated cathode material accounts for 90% to 100% of the mass of the cathode active material.

[0240] By controlling the sum of the mass percentages of carbon conductive material and conductive polymer in the composite-coated cathode material (F... 20 The mass percentage of the coating layer in the composite coated cathode material (F) M ), the average thickness of the coating layer (D1), and the sum of the mass percentages of carbon conductive material and conductive polymer in the coating layer (F). 21 ), the mass percentage of composite-coated cathode materials in cathode active materials (F) C When one or more parameters in the above-mentioned range are within the range, it is beneficial to control the coating amount within a more suitable range, which is beneficial to suppress the volume deformation of the positive electrode active material and improve the electron transport capability of the positive electrode active layer, while also better taking into account the energy density.

[0241] In some embodiments, the mass percentage of the blended conductive agent in the positive electrode active layer is 0-3%, optionally 0-1.5%, and may also be any of the following percentages or a range selected from any two of the following percentages: 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, etc.; the blended conductive agent refers to different particles located outside the particles of the composite coated positive electrode material.

[0242] In some embodiments, the mass percentage of the blended conductive agent in the positive electrode active layer is 0 to 1.5%.

[0243] In this application, unless otherwise specified, "blended conductive agent" refers to different particles located outside the particles of the composite-coated cathode material. The blended conductive agent can be any conductive agent known in the art for use in solid-state battery cathodes. Without limitation, the blended conductive agent may include one or more of superconducting carbon, acetylene black, conductive carbon black (SP), Ketjen black (ECP), carbon dots, carbon nanotubes (CNTs), graphene, and carbon fibers. An example of carbon nanofiber is vapor-grown carbon fiber (VGCF).

[0244] The type of blended conductive agent can be the same as or different from the type of carbon conductive material in the coating layer of the composite coated cathode material.

[0245] By introducing composite coated cathode materials into the cathode active layer, it is beneficial to control the amount of blended conductive agent within a low range, to increase the loading of cathode active material, and to improve energy density while suppressing the volume deformation of cathode active material and enhancing the electron transport capability of cathode active layer.

[0246] In some embodiments, the positive electrode active layer further includes a positive electrode electrolyte material, which satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0247] (d1) The Young's modulus of the positive electrode electrolyte material at 25℃ is 5GPa to 100GPa, which can be selected as 10GPa to 50GPa, or any of the following values ​​or a range composed of any two of the following values: 5GPa, 6GPa, 8GPa, 10GPa, 15GPa, 20GPa, 25GPa, 30GPa, 35GPa, 40GPa, 45GPa, 50GPa, 60GPa, 70GPa, 80GPa, 90GPa, 100GPa, etc.

[0248] (d2) Positive electrode electrolyte materials include one or more of the following: sulfide solid electrolytes, halide solid electrolytes, halide oxide solid electrolytes, and polymer electrolytes.

[0249] In some embodiments, the positive electrode electrolyte material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0250] (d1') The Young's modulus of the positive electrode electrolyte material at 25℃ is 10 GPa to 50 GPa;

[0251] (d2') Positive electrode electrolyte materials include sulfide solid electrolytes.

[0252] In some embodiments, the positive electrode electrolyte material includes a sulfide-based solid electrolyte. Among the many solid electrolyte materials currently available, sulfide electrolytes possess extremely high ionic conductivity (e.g., ≥1 mS / cm at room temperature) and excellent mechanical properties, making them one of the most promising solid electrolyte materials for solid-state battery systems.

[0253] Non-limitingly, sulfide solid electrolytes may include one or more of binary sulfide solid systems and ternary sulfide solid systems. Non-limitingly, binary sulfide solid systems may include Li₂S-P₂S₅ (such as Li₇P₃S₅).11 The ternary sulfide solid-state system may include one or more of Li₂S-SiS₂, Li₂S-GeS₂, and Li₂S-B₂S₃. Non-limitingly, the ternary sulfide solid-state system may include Argyrodite-type sulfide electrolytes, Li₂S-M… 5 S2-P2S5 ternary sulfide electrolyte, lithium germanium phosphorus sulfide electrolyte, Li2S-P2S5-M 6 S-ternary sulfide electrolyte, Li2S-P2S5-M 6 Cl is one or more of a ternary sulfide electrolyte and a thio-LISICON type sulfide electrolyte; wherein, M 5 It may include one or more elements selected from silicon (Si), germanium (Ge), tin (Sn), and aluminum (Al); M 6 It may include one or more elements selected from Ge, Al, Sn, lead (Pb), antimony (Sb), Si, and arsenic (As).

[0254] In some embodiments, the sulfide solid electrolyte includes one or more of the following: argyrogermanium sulfide type sulfide electrolyte, LGPS type sulfide electrolyte, and lithium pentaphosphide-sulfide complex type sulfide electrolyte. Unless otherwise stated, the argyrogermanium sulfide type sulfide electrolyte has an argyrogermanium sulfide crystal phase structure. Non-limiting examples of argyrogermanium sulfide type sulfide electrolytes may include Li6PS5Cl, Li... 5.5 PS 5.5 Cl 1.5 Li 5.7 PS5Cl 1.3 Etc. Unless otherwise stated, LGPS-type sulfide electrolytes possess an LGPS-type crystalline phase structure. Non-limiting examples of LGPS-type sulfide electrolytes include Li… 10 GeP2S 12 Non-limitingly, lithium pentaphosphine sulfide complex-type sulfide electrolytes may include those with the chemical formula (100-uv)Li₂S·uP₂S₅·vM. 3 m N 3 n Sulfide electrolytes, of which 0 <u<100,0≤v<100,0≤u+v<100,0≤m<4,0≤n<6,M 3 It can be selected from, but is not limited to, one or more elements from Li, B, Ge, Si, Sn, and Sb, N 3 It can be selected from one or more elements from S, Se, Te, O, Cl, Br, I, and F.

[0255] Non-limiting examples of oxide solid electrolytes may include LISICON-type oxide electrolytes (such as γ-Li3PO4, etc.) and NASICON-type oxide electrolytes (such as Li...). 1+δ2 Al δ2 Ge 2-δ2 (PO4)3,Li 1+δ2 Al δ2 Ti 2-δ2 (PO4)3, etc., 0≤δ2≤1), Garnet type (such as Li7La3Zr2O) 12 (etc.), perovskite-type oxide electrolytes (such as Li, etc.) 3·δ3 La 2 / 3-δ One or more of the following: 3TiO3, 0≤δ3≤0.5).

[0256] Non-limiting examples of halide solid electrolytes may include one or more of Li3InCl6, Li3YCl6, Li3ScCl6, Li3ErCl6, Li2ZrCl6, etc.

[0257] In this application, unless otherwise specified, "Young's modulus" has a well-known meaning in the art, reflecting the flexibility or rigidity of a material; the smaller the Young's modulus, the better the flexibility and the weaker the rigidity. Unless otherwise specified, the "Young's modulus" of the positive electrode electrolyte material can be the Young's modulus measured by the AFM method in shear mode. Those skilled in the art can obtain the test results of Young's modulus using conventional techniques in the art. The Young's modulus of the positive electrode electrolyte material can be obtained by testing with an atomic force microscope (AFM, such as Dimension Icon / Dimension Icon XR) equipped with a QNM module. Powder samples can be dispersed on a silicon wafer using a suitable solvent and dried before testing. The average Young's modulus can be obtained by measuring the shear modulus under different pressures and fitting the pressure and shear modulus data; the obtained value can be used as the test value of the "Young's modulus" of the sample. For example, when testing the Young's modulus of sulfide solid electrolytes, the solvent used can be a non-polar or low-polar organic solvent, such as p-xylene or pseudotrimethylbenzene. Unless otherwise specified, the test temperature is 25°C.

[0258] Positive electrode electrolyte materials with the aforementioned Young's modulus (such as sulfide solid electrolytes) have good flexibility, which is beneficial for improving the solid-solid contact of the positive electrode interface and reducing the interface impedance, thus improving the cycle performance of solid-state batteries.

[0259] In some implementations, the composite-coated cathode material satisfies one or more of the following characteristics:

[0260] (e1) The positive electrode active body includes one or more of disordered rock salt phase positive electrode materials, spinel phase positive electrode materials and lithium titanate;

[0261] (e2) The positive electrode active material includes one or more of the following: lithium nickel cobalt manganese-based oxide, lithium nickel cobalt aluminum-based oxide, lithium cobalt oxide, chalcogenide positive electrode active material, lithium manganese oxide, lithium nickel oxide, and lithium-rich manganese-based positive electrode active material.

[0262] In some implementations, the composite-coated cathode material satisfies one or more of the following characteristics:

[0263] (e1') The positive electrode active body includes one or more of the disordered rock salt phase positive electrode and the spinel phase positive electrode;

[0264] (e2') The positive electrode active material includes one or more of lithium nickel cobalt manganese-based oxides, lithium cobalt oxide, and chalcogenide positive electrode active materials.

[0265] In some embodiments, the positive electrode active body includes an oxide-based positive electrode active material.

[0266] In some embodiments, the oxide-based positive electrode active material has a layered crystal structure.

[0267] In some embodiments, the oxide-based positive electrode active material includes lithium transition metal oxides, in which case the positive electrode active body includes lithium transition metal oxides.

[0268] Composite coated cathode materials include at least a cathode active body. The "cathode active body" is the fundamental part of the composite coated cathode material that has the ability to reversibly extract and insert active ions.

[0269] In some implementations, the positive electrode active body comprises a lithium transition metal oxide.

[0270] In this application, unless otherwise specified, "lithium transition metal oxide" refers to a positive electrode active material containing lithium, transition metal, and oxygen. It is understood that lithium transition metal oxides have the ability to reversibly extract and insert active ions. Therefore, lithium transition metal oxides include non-lithium metal elements, and non-lithium metal elements include transition metal elements. Non-limitingly, in lithium transition metal oxides, the molar percentage of transition metal elements relative to non-lithium metal elements can be 90% to 100%, and can also be any of the following percentages or a range selected from any two of the following percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, etc.

[0271] In this application, unless otherwise specified, "non-lithium metal element" refers to a metal element that is different from lithium (Li).

[0272] In this application, unless otherwise specified, the definition of lithium transition metal oxides encompasses lithium transition metal oxides and their modified forms. Modified forms of lithium transition metal oxides include the lithium transition metal oxide itself and modifying elements. Modifying elements may include one or more of doping elements and coating elements. Modified forms of lithium transition metal oxides still fall within the scope of lithium transition metal oxides.

[0273] In this application, unless otherwise specified, "a modified positive electrode active material" includes the positive electrode active material itself and the modifying element. Furthermore, the modifying element may exist as a dopant element, a coating element, or a combination of a dopant element and a coating element. Unless otherwise specified, "a modified positive electrode active material" still falls within the scope of positive electrode active materials.

[0274] Non-limiting examples of lithium transition metal oxides include, but are not limited to, lithium transition metal oxides known in the art for use as cathode active materials in solid-state batteries. Examples of lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their modifications. Non-limiting examples of lithium cobalt oxides include LiCoO2; non-limiting examples of lithium nickel oxides include LiNiO2; non-limiting examples of lithium manganese oxides include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides 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.

[0275] In some embodiments, the lithium transition metal oxide has a layered crystal structure.

[0276] In some embodiments, the lithium transition metal oxide includes lithium nickel-based oxides. In this application, unless otherwise specified, "lithium nickel-based oxide" refers to a lithium transition metal oxide comprising lithium, nickel, and oxygen. In this case, the non-lithium metal element in the lithium transition metal oxide includes nickel. Without limitation, the lithium nickel-based oxide may include one or more of lithium nickel cobalt manganese-based oxides and lithium nickel cobalt aluminum-based oxides.

[0277] In some embodiments, the positive electrode active material includes lithium nickel cobalt manganese-based oxide, lithium nickel cobalt aluminum-based oxide, lithium cobalt oxide, lithium iron phosphate, chalcogenide positive electrode active material (such as S), lithium manganese oxide, lithium niobate, lithium nickel oxide, lithium-rich manganese-based positive electrode active material, and Li4Ti5O. 12 One or more of the following.

[0278] In some embodiments, the positive electrode active material includes one or more of lithium nickel cobalt manganese-based oxides, lithium nickel cobalt aluminum-based oxides, lithium cobalt oxide, chalcogenide positive electrode active materials, lithium manganese oxide, lithium nickel oxide, and lithium-rich manganese-based positive electrode active materials.

[0279] In some embodiments, the positive electrode active body includes one or more of lithium nickel cobalt manganese-based oxides, lithium cobalt oxide, and chalcogenide positive electrode active materials.

[0280] In this application, unless otherwise specified, "lithium nickel cobalt manganese-based oxide" refers to a lithium transition metal oxide comprising lithium, nickel, cobalt, manganese, and oxygen, and more specifically, a lithium nickel-based oxide. It is understood that lithium nickel cobalt manganese-based oxide includes lithium, non-lithium metal elements, and oxygen, wherein the non-lithium metal elements include nickel, cobalt, and manganese. In this application, unless otherwise specified, lithium nickel cobalt manganese-based oxides used as positive electrode active materials typically have a layered structure.

[0281] In lithium nickel cobalt manganese-based oxides, the ratio of the sum of the atomic molar ratios of nickel, cobalt, and manganese to the sum of the atomic molar ratios of non-lithium metal elements is denoted as R. NCM In a non-restrictive sense, R NCM It can be 0.9 to 1, can be selected from 0.96 to 1, or can be any of the following values, or selected from a range consisting of any two of the following values: 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1, etc.

[0282] In this application, unless otherwise stated, “lithium nickel cobalt aluminum based oxide” refers to lithium transition metal oxides that include lithium, nickel, cobalt, aluminum and oxygen.

[0283] Non-limiting examples of the chalcogen-based positive electrode active material may include one or more of elemental sulfur, elemental selenium, elemental tellurium, sulfur-selenium compounds, and the like.

[0284] In the present application, unless otherwise specified, the "lithium-rich manganese-based positive electrode active material" refers to a positive electrode active material containing Li2MnO3, and may also optionally contain LiM 7 O2, where M 7 is a transition metal element. Non-limitingly, M 7 may include one or more of transition metal elements such as Ni, Co, Mn, Cr, Fe, Al, Nb, Zr, Mo, Ta, etc. The layered lithium-rich manganese-based positive electrode active material has advantages such as high specific capacity, high voltage platform, and easy synthesis. In some embodiments, the lithium-rich manganese-based positive electrode active material is a layered lithium-rich manganese-based positive electrode active material. In some embodiments, the chemical formula of the layered lithium-rich manganese-based positive electrode active material is y1(Li2MnO3)·(1 - y1)(LiM 7 O2), where 0 < y1 ≤ 1, and optionally, 0 < y1 < 1.

[0285] Those skilled in the art can use one or more of elemental analysis methods including but not limited to energy dispersive spectrometer (EDS), X-ray diffraction (XRD) technology, inductively coupled plasma spectrometer (ICP method), etc. to perform composition analysis on the positive electrode active material in the positive electrode layer.

[0286] Taking a solid-state battery with active ions including lithium ions as an example, it can be understood that during the charge and discharge process of the solid-state battery, the insertion and extraction and consumption of lithium (Li) will occur, and the content of Li in the positive electrode layer is different when the battery is discharged to different states. In the exemplary description of the positive electrode active material in the present application, unless otherwise specified, the content of Li can be the initial state of the material or a non-initial state after charge and discharge cycles. When the positive electrode active material is applied to the positive electrode layer in a solid-state battery system, after charge and discharge cycles, the content of Li in the positive electrode active material contained in the positive electrode layer usually changes. Among them, the content of Li can be measured by atomic molar content, but is not limited thereto. Regarding "the content of Li is the initial state of the material", the initial state of the material refers to the state before being placed in the positive electrode layer. It can be understood that new materials or new substances obtained by appropriately modifying the listed positive electrode active materials are also within the scope of the positive electrode active material. The aforementioned appropriate modification refers to acceptable modification methods for the positive electrode active material. Non-limiting examples include one or more of coating modification and doping modification. In the exemplary description of the positive electrode active material in the present application, the content of oxygen (O) is usually the theoretical state value. Lattice oxygen release will cause changes in the atomic molar content of oxygen, and the actual content of O will fluctuate. Among them, the content of O can be measured by atomic molar content, but is not limited thereto.

[0287] Disordered rock salt phase cathode materials, spinel phase cathode materials, and lithium titanate exhibit small volume changes during charge-discharge cycles. By incorporating these cathode active materials into the cathode active body, it is beneficial to improve the solid-solid contact of the cathode interface during charge-discharge cycles.

[0288] By incorporating positive electrode active materials such as lithium nickel cobalt manganese-based oxides, lithium nickel cobalt aluminum-based oxides, lithium cobalt oxide, chalcogenide positive electrode active materials, lithium manganese oxide, lithium nickel oxide, and lithium-rich manganese-based positive electrode active materials into the positive electrode active body, it is beneficial to provide high energy density.

[0289] Those skilled in the art can identify the types and structures of components in solid-state batteries using one or more of the following detection methods, including but not limited to: Fourier transform infrared (FT-IR) spectroscopy, ultraviolet spectroscopy, and proton nuclear magnetic resonance (NMR) spectroscopy. 1 Methods include 1H NMR, X-ray diffraction (XRD), gel permeation chromatography (GPC), high performance liquid chromatography (HPLC), mass spectrometry, inductively coupled plasma atomic emission spectrometry (ICP), and energy dispersive spectroscopy (EDS). The sample preparation and testing methods for these methods are known to those skilled in the art, and the test parameters can be appropriately adjusted according to the sample characteristics.

[0290] In some implementations, the solid-state battery is an all-solid-state battery.

[0291] 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".

[0292] In some embodiments, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0293] In some implementations, the solid-state battery is a lithium-ion secondary battery; in this case, the active ions include lithium ions.

[0294] In some implementations, the solid-state battery is an all-solid-state lithium-ion secondary battery, which is both an all-solid-state battery and a lithium-ion secondary battery.

[0295] 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.

[0296] 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.

[0297] 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".

[0298] 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.

[0299] In some embodiments, the solid-state battery cell 5 includes a solid-state cell 52.

[0300] In some implementations, the solid-state cell is an all-solid-state cell.

[0301] In some embodiments, the solid-state cell 52 (which may be an all-solid-state cell) includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0302] The following is a description of the positive electrode layer.

[0303] The positive electrode layer can be formed based on a solid electrolyte membrane or provided by a pre-fabricated positive electrode sheet.

[0304] Unless otherwise stated, the positive electrode layer in this application includes at least a positive electrode active layer.

[0305] Unless otherwise stated in this application, the positive electrode sheet includes at least a positive active layer.

[0306] In this application, unless otherwise specified, the positive electrode active layer includes at least a positive electrode active material, and typically also includes a solid electrolyte material. In this application, unless otherwise specified, the solid electrolyte material in the positive electrode layer may be referred to as "positive electrode electrolyte material". The positive electrode electrolyte material can enhance the ion conductivity of the positive electrode layer, reduce interfacial impedance, and promote the charge transfer efficiency and full release of the capacity of the positive electrode active material with the external environment.

[0307] It is understandable that positive electrode active materials include composite coated positive electrode materials.

[0308] The types of positive electrode active materials in the positive electrode active layer can be referred to in the context of this application. Optionally, it may also include other types of positive electrode active materials known in the art that can be used in the positive electrode layer of solid-state batteries.

[0309] As a non-limiting example, other types of positive electrode active materials may include one or more of the following: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modifications. 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 can be found above. Non-limiting examples of lithium-containing phosphates with an olivine structure may include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium iron phosphate include LiFePO4 (also abbreviated as LFP). Examples of lithium manganese phosphate include LiMnPO4.

[0310] Non-limitingly, the mass percentage of the positive electrode active material in the positive electrode active layer can be ≥70%, or 70% to 95%, or even 75% to 90%, or any of the following percentages or a range selected from any two of the following percentages: 70%, 72%, 74%, 75%, 76%, 78%, 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, etc.

[0311] The types of solid electrolyte materials in the positive electrode active layer can be found in the context of this application. Optionally, other types of solid electrolyte materials known in the art that can be used in the positive electrode layer of a solid-state battery may also be included.

[0312] Non-limitingly, the mass percentage of the positive electrode electrolyte material in the positive electrode active layer can be 0.1% to 30%, optionally 5% to 30%, further optionally 5% to 25%, even further optionally 5% to 20%, even further optionally 5% to 15%, and can also be any of the following percentages or a range selected from any two of the following percentages: 0.1%, 1%, 2%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, etc.

[0313] In some embodiments, the positive electrode active layer may optionally include a conductive agent (which may be referred to as a positive electrode conductive agent).

[0314] The types of conductive agents in the positive electrode active layer can be found in the context of this application. Optionally, other types of conductive agents known in the art that can be used in the positive electrode layer of a solid-state battery may also be included.

[0315] In some embodiments, the positive electrode conductive agent includes a blended conductive agent. Non-limitingly, the mass percentage of the blended conductive agent in the positive electrode conductive agent can be 80% to 100%, optionally 90% to 100%, or any of the following percentages or a range selected from any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, etc.

[0316] Non-limitingly, the mass percentage of the positive electrode conductive agent in the positive electrode active layer can be 0-5%, optionally 0-3%, and further optionally 0-1.5%. In some embodiments, the mass percentage of the positive electrode conductive agent in the positive electrode active layer can be 0.1%-5%, 0.1%-3%, or 0.1%-1.5%.

[0317] In some embodiments, the positive electrode active layer optionally includes a binder. The binder in the positive electrode active layer may be referred to as a positive electrode binder. The positive electrode binder may be a binder known in the art for use in the positive electrode layer of a solid-state battery. As a non-limiting example, the positive electrode binder may include one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. Typically, the mass percentage of the positive electrode binder in the positive electrode active layer may be 0-5%, optionally 0-3%, and more preferably 0-2%. In some embodiments, the mass percentage of the positive electrode binder in the positive electrode active layer is 0.1%-5%, may also be 0.5%-3%, and more preferably 0.5%-2%.

[0318] In some embodiments, the positive electrode layer includes a positive electrode current collector and a positive electrode active layer disposed on at least one surface of the positive electrode current collector.

[0319] 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 layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0320] 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 alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limitingly, in the positive electrode current collector, the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0321] Positive electrode sheets can be prepared using dry methods. For example, they can be dry-pressed into membranes.

[0322] In some embodiments, the positive electrode sheet can be prepared by dry mixing the components used to prepare the positive electrode sheet, such as the positive active material, the positive electrolyte material, the positive conductive agent, the positive binder, and any other components, and rolling them into a positive electrode sheet.

[0323] In some embodiments, the positive electrode sheet can be prepared by: dry mixing the components used to prepare the positive electrode sheet, such as the positive electrode active material, positive electrode electrolyte material, 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 pressing to form a self-supporting positive electrode sheet; and hot rolling bonding the self-supporting positive electrode sheet with 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 pressing process can be performed using a Banbury mixer. Non-limitingly, the temperature for hot rolling pressing can be 75°C to 85°C, and further, such as 78°C, 80°C, 82°C, etc.

[0324] The following is a description of the negative electrode layer.

[0325] The negative electrode layer can be formed based on a 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 solid-state batteries.

[0326] In this application, unless otherwise specified, the negative electrode layer includes at least a negative electrode active layer.

[0327] In this application, unless otherwise stated, the negative electrode sheet includes at least a negative electrode active layer.

[0328] Unless otherwise stated in this application, the negative electrode active layer includes at least a negative electrode active material.

[0329] Non-limiting, the negative electrode active layer may include a solid electrolyte material. In this application, unless otherwise specified, the solid electrolyte material in the negative electrode active layer may be referred to as "negative electrode electrolyte material".

[0330] Non-limiting, the mass percentage content of the negative electrode active material in the negative electrode active layer can be ≥80%, and more preferably ≥90%. Non-limiting, the mass percentage content of the negative electrode active material in the negative electrode active layer can be 80% to 99%, optionally 90% to 99%, and more preferably 95% to 99%, and can also be any of the following percentages or a range selected from any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc.

[0331] Non-limitingly, the mass percentage of the negative electrode electrolyte material in the negative electrode active layer can be 0% to 30%, preferably 0.1% to 30%, and further preferably 5% to 20%.

[0332] In some implementations, the negative electrode active material is a lithium indium alloy (InLi alloy).

[0333] In some embodiments, the negative electrode layer or negative electrode sheet is an InLi alloy film.

[0334] In some embodiments, the negative electrode active material may also be a negative electrode active material known in the art for use in solid-state batteries. As a non-limiting example, the negative electrode active material may include one or more of the following materials: elemental silicon, elemental tin, silicon-carbon composites, silicon suboxide, graphite, and metallic lithium. However, this application is not limited to these materials or substances, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0335] In some embodiments, the negative electrode sheet may include a negative current collector and a negative active layer disposed on at least one surface of the negative current collector, the negative active layer comprising a negative active material. As a non-limiting example, the negative current collector has two surfaces opposite to each other in its own thickness direction, and the negative active layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0336] 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 at least one of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limitingly, in the negative electrode current collector, the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0337] In some embodiments, the negative electrode active 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 mass percentage of the negative electrode conductive agent in the negative electrode active layer may be 0–15%, more preferably 0–10%, and even more preferably 0–5%.

[0338] In some embodiments, the negative electrode active layer optionally includes an adhesive (denoted as negative electrode adhesive). As a non-limiting example, the negative electrode adhesive 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 mass percentage of the negative electrode adhesive in the negative electrode active layer may be 0-10%, more further 1%-10%, even more further 1%-5%, and even more preferably 1%-3%.

[0339] In some embodiments, the negative electrode active layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)). The mass percentage of other additives in the negative electrode active layer may be 0–15%, more preferably 0–10%, even more preferably 0–5%, even more preferably 0–3%, and even more preferably 0–2%.

[0340] Negative electrode sheets can be prepared using either dry or wet methods. For example, they can be dry-pressed into films under low pressure conditions, such as 1 MPa to 2 MPa. Alternatively, they can be wet-coated into films.

[0341] 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 material, negative electrode conductive agent, negative electrode binder, and any other components, in a solvent to form a negative electrode slurry. Taking a sulfide-based solid electrolyte as an example, a non-limiting example of a solvent is p-xylene. Further, the negative electrode slurry is coated onto at least one surface of the negative electrode current collector, and after drying or other processes, the negative electrode sheet is obtained. 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.

[0342] The following is a description of the solid electrolyte layer.

[0343] 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.

[0344] 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.

[0345] It is understood that the solid electrolyte layer includes a solid electrolyte material. The solid electrolyte material in the solid electrolyte layer can be any solid electrolyte material known in the art that can be used in solid-state batteries.

[0346] The types of solid electrolyte materials present in different film layers of a solid-state battery can be the same or different. For example, the solid electrolyte materials in the positive electrode layer and the solid electrolyte layer can be the same or different. As a non-limiting example, the solid electrolyte materials in different film layers of a solid-state battery can include one or more of the following: sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, and polymer solid electrolytes.

[0347] As a non-limiting example, in different film layers of a solid-state battery, the solid electrolyte material can independently include, but is not limited to, one or more of oxide-based solid electrolytes, sulfide-based solid electrolytes, and halide-based solid electrolytes. In some embodiments, the solid electrolyte material can independently include, but is not limited to, one or more of Argyrodite-type sulfide electrolytes and halide electrolytes. Non-limiting examples of oxide-based solid electrolytes may include LISICON-type oxide electrolytes (such as γ-Li3PO4), NASICON-type oxide electrolytes (such as Li... 1+δ2 Al δ2 Ge 2-δ2 (PO4)3,Li 1+δ2 Al δ2 Ti 2-δ2(PO4)3, etc., 0≤δ2≤1), Garnet type (such as Li7La3Zr2O) 12 (etc.), perovskite-type oxide electrolytes (such as Li, etc.) 3·δ3 La 2 / 3-δ3 One or more of the following: TiO3, etc. (0≤δ3≤0.5). Non-limiting examples of sulfide solid electrolytes may include Li. 10 GeP2S 12 Li₂S-P₂S₅, Li₇P₃S 11 Argyrodite type (such as Li6PS5Cl, Li 5.5 PS 5.5 Cl 1.5 Li 5.7 PS5Cl 1.3 One or more of the following, and may also include sulfide solid electrolytes as described in the context. Non-limiting examples of halide solid electrolytes may include one or more of the following: Li3InCl6, Li3YCl6, Li3ScCl6, Li3ErCl6, Li2ZrCl6, etc.

[0348] 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 materials of the solid electrolyte layer onto an electrode layer.

[0349] Solid electrolyte layers can also be prepared using a wet process. The electrolyte slurry used includes at least a solid electrolyte material and an organic solvent, and usually also includes one or more of a binder and a dispersant.

[0350] In a non-limiting manner, the positive electrode layer, the solid electrolyte layer, and the negative electrode layer can be assembled in a stacked manner, with the solid electrolyte layer placed between the positive electrode layer and the negative electrode layer.

[0351] Solid-state batteries are prepared using methods including, but not limited to, those described in the second aspect of this application.

[0352] Non-limitingly, a solid-state battery cell can be prepared by sequentially placing a positive electrode, a raw material layer of solid electrolyte material, and a negative electrode, with the raw material layer of solid electrolyte material placed between the positive and negative electrode, and then pressing them together.

[0353] 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.

[0354] 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.

[0355] 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 This is an example of a square-structured solid-state battery cell 5.

[0356] In some of these implementations, reference is made to... Figure 2 The outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 can be placed over the opening to close the receiving cavity. A solid-state battery cell 52 is encapsulated within the receiving cavity. The number of solid-state battery cells 52 contained in a single solid-state battery cell 5 may be one or more, which can be selected by those skilled in the art according to actual needs.

[0357] Solid-state batteries can be battery device 4 or battery pack 1.

[0358] 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.

[0359] Figure 3 This is battery device 4, used as an example. (See reference...) 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 manner. Furthermore, the multiple solid-state battery cells 5 can be fixed in place using fasteners.

[0360] 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.

[0361] 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.

[0362] Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5The battery pack 1 may include a battery box and multiple battery devices 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery devices 4. The multiple battery devices 4 can be arranged in any manner within the battery box.

[0363] In a second aspect of this application, a method for preparing a solid-state battery is provided, which can be used to prepare the solid-state battery of the first aspect of this application.

[0364] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps: stacking a positive electrode, a solid electrolyte material layer and a negative electrode in sequence, pressing them together to prepare a solid-state battery;

[0365] The positive electrode sheet includes a positive active layer, which includes a composite coated positive electrode material. The composite coated positive electrode material includes a positive active body and a coating layer located on the surface of the positive active body. The coating layer includes a carbon conductive material and a conductive polymer.

[0366] In some embodiments, the positive electrode active layer includes the features of the positive electrode active layer in the solid-state battery described in the first aspect of this application.

[0367] In some embodiments, the composite-coated cathode material is prepared using a method comprising the following steps:

[0368] A carbon composite conductive polymer material and a positive electrode active bulk material are dry-ball-milled and then heated under a flowing inert atmosphere to prepare a composite-coated positive electrode material. The carbon composite conductive polymer material comprises a polymer matrix formed by a conductive polymer and carbon conductive material dispersed within the polymer matrix. The heating temperature is denoted as T1, the glass transition temperature of the conductive polymer is denoted as Tg1, and the thermal decomposition temperature of the conductive polymer is denoted as Td1, satisfying Tg1. <T1<Td1。

[0369] In this application, the "glass transition temperature (Tg)" and "thermal decomposition temperature (Td)" of the polymer have the meanings known in the art.

[0370] By dry ball milling and mixing the carbon composite conductive polymer material with the positive electrode active body at the aforementioned temperature T1, the conductive polymer in the carbon composite conductive polymer material softens but does not decompose, exhibiting good flexibility, which allows the carbon composite conductive polymer material to be tightly coated on the surface of the positive electrode active body.

[0371] In some embodiments, the method for fabricating solid-state batteries satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0372] (f1) Tg1+5℃≤T1≤Td1-5℃; Non-limitingly, T1 can also be any of the following temperatures or greater than or equal to any of the following temperatures: Tg1+10℃, Tg1+12℃, Tg1+14℃, Tg1+15℃, Tg1+20℃, Tg1+25℃, Tg1+30℃, etc.; Non-limitingly, T1 can also be any of the following temperatures or less than or equal to any of the following temperatures: Td1-10℃, Td1-12℃, Td1-14℃, Td1-15℃, Td1-20℃, Td1-25℃, Td1-30℃, etc.

[0373] (f2) The temperature for heat treatment is 100℃~200℃, and may also be any of the following temperatures or a range consisting of any two of the following temperatures: 100℃, 110℃, 120℃, 140℃, 150℃, 160℃, 180℃, 200℃, etc.

[0374] (f3) The duration of the heat treatment is 60 min to 360 min, and may also be any of the following durations or a range consisting of any two of the following durations: 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 150 min, 160 min, 180 min, 200 min, 240 min, 250 min, 260 min, 280 min, 300 min, 320 min, 340 min, 350 min, 360 min, etc.;

[0375] (f4) The flowing inert atmosphere includes one or more of argon and nitrogen; the flow rate of the flowing inert gas is 10 m / s. 3 / h~100m 3 / h can also be any of the following flow velocities or a range consisting of any two of the following flow velocities: 10m 3 / h, 20m 3 / h, 30m 3 / h, 40m 3 / h, 50m 3 / h、60m 3 / h、80m 3 / h、100m 3 / h etc.;

[0376] (f5) The rotation speed for dry ball milling is 300 rpm to 600 rpm, and may also be any of the following rotation speeds or a range consisting of any two of the following rotation speeds: 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, etc.

[0377] (f6) The ball milling time for dry ball milling is 12h to 36h, and can also be any of the following times or a range consisting of any two of the following times: 12h, 14h, 15h, 16h, 18h, 20h, 22h, 24h, 25h, 26h, 8h, 30h, 32h, 34h, 35h, 36h, etc.

[0378] (f7) The carbon composite conductive polymer material is prepared by a method comprising the following steps: mixing carbon conductive material raw material and conductive polymer raw material in a dispersion solvent, performing liquid-phase ball milling, and drying to remove the dispersion solvent, thereby preparing the carbon composite conductive polymer material; non-limitingly, the dispersion solvent may include one or more of ethanol, toluene, methanol and diethyl ether; non-limitingly, the rotation speed of the liquid-phase ball mill may be 300 rpm to 600 rpm, or any of the following rotation speeds or a range selected from any two of the following rotation speeds: 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, etc.; non-limitingly, the ball milling time may be 12 h to 36 h, or any of the following time durations or a range selected from any two of the following time durations: 12 h, 14 h, 15 h, 16 h, 18 h, 20 h, 22 h, 24 h, 25 h, 26 h, 8 h, 30 h, 32 h, 34 h, 35 h, 36 h, etc.

[0379] (f8) The positive electrode sheet is prepared by a method comprising the following steps: mixing a positive electrode material composition comprising a composite coated positive electrode material and a positive electrode electrolyte material, and forming a membrane under solvent-free conditions; wherein, the positive electrode material composition may optionally include a binder;

[0380] (f9) The solid-state battery described in the first aspect of this application is prepared.

[0381] By using liquid-phase ball milling, the conductive polymer is dissolved in the dispersion solvent, which allows the carbon conductive material to be more uniformly dispersed in the polymer matrix formed by the conductive polymer.

[0382] Adding heating under a flowing argon atmosphere after heat treatment helps to make the carbon composite conductive polymer material bond more tightly with the positive electrode active body, which is beneficial to further improve the conductivity of the composite coated positive electrode material surface.

[0383] The size and size distribution of the carbon conductive material raw material can be controlled according to the relevant description of the composite coated cathode material in the first aspect of this application. The particle size and distribution can be controlled by combining known methods such as sieving.

[0384] The maximum and average particle size of carbon conductive material raw materials can be tested using the following method: The powder sample of the material to be tested is adhered to conductive adhesive and subjected to scanning electron microscopy (SEM) at a magnification of 500X to 30KX. The maximum diameter of the selected particle in each direction of the SEM image is recorded as the "maximum particle size". Multiple particles can be selected for statistical analysis. The distribution range of the maximum particle size of the counted particles is recorded; the number of counted particles can be at least 5, and optionally at least 6. The average of the "maximum particle sizes" of multiple particles is taken to obtain the "average particle size" of the material to be tested; the number of counted particles can be at least 6, and optionally at least 10. For example, the scanning electron microscope (SEM) can be a ZEISS Sigma 300, a JEOL scanning electron microscope, or an Axia ChemiSEM scanning electron microscope.

[0385] Non-limitingly, in the composite coated cathode material used to prepare the cathode layer of the solid-state battery, x2 can be any of the following values, or a range selected from any two of the following values: 0.98, 0.99, 1.00, 1.01, 1.02, etc., or any range selected from: 0.98 to 1.02, etc. In some embodiments, x2 is 1.

[0386] Non-limitingly, in the composite coated cathode material used to prepare the cathode layer of the solid-state battery, x3 can be any of the following values, or a range selected from any two of the following values: 1.96, 1.97, 1.98, 1.99, 2.00, 2.01, 2.02, 2.03, 2.04, etc., or any of the following ranges: 1.96–2.04, 1.98–2.02, 1.99–2.01, etc. In some embodiments, x3 is 2.

[0387] In a third aspect of this application, an electrical device is provided, comprising at least one of the solid-state battery described in the first aspect of this application and a solid-state battery prepared by the method for preparing a solid-state battery described in the second aspect of this application.

[0388] In some embodiments, the electrical device includes at least one of the solid-state batteries of any of the embodiments provided in this application.

[0389] 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.

[0390] As an electrical device, solid-state batteries can be selected based on its usage requirements.

[0391] Figure 6 Here is an example of an electrical device 6. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device for solid-state batteries, a battery device or battery pack can be used.

[0392] 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.

[0393] The following describes some embodiments of this application. The described embodiments are only a part of the embodiments of this application, and not all of them. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application and its applications. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0394] Unless otherwise specified in the examples, the procedures described above, or those described in the literature in this field, or those described in the product instructions, shall be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products, or products that can be synthesized using conventional methods from commercially available products.

[0395] In the following examples, room temperature refers to 20°C to 30°C.

[0396] It should be noted that the following embodiments and examples use all-solid-state batteries as non-limiting examples of solid-state batteries, and further use all-solid-state lithium-ion secondary batteries as an example.

[0397] In the following examples, unless otherwise specified, the use of organic solvents to disperse sulfide-based solid electrolyte materials is involved. The organic solvent may be one or more of xylene, trimethylbenzene, butyl butyrate, heptane, etc., and may further be pseudotrimethylbenzene or p-xylene.

[0398] In the following embodiments and comparative examples, unless otherwise stated, the steps involving sulfide solid electrolytes and materials or films containing them are carried out in an argon atmosphere.

[0399] In the following examples, unless otherwise specified, the parameters involved can be confirmed and / or adjusted by referring to the test methods described above. For example, this includes tests involving ionic conductivity (25°C electronic conductivity of carbon conductive materials, conductive polymers, composite-coated cathode materials, etc.), maximum and average particle sizes of carbon conductive material raw materials, and parameters related to the coating layer (such as the percentage of the coating layer's coverage area on the particle surface of the composite-coated cathode material (F...). A ( ), average thickness of the coating layer, weight-average molecular weight of the conductive polymer, Young's modulus at 25°C of the positive electrode electrolyte material, etc.

[0400] The maximum particle size of the carbon conductive materials used in the following examples is in the range of 10 nm to 0.5 μm, which can be controlled by sieving; the specific surface area of ​​the carbon conductive materials is in the range of 1200 m². 2 / g~3000m 2 Within the range of / g, the electronic conductivity of carbon conductive material raw materials at 25℃ all meet the requirement of ≥10. 5 mS / cm; the intermediate molecular weight of the conductive polymer raw materials is in the range of 10kDa to 3000kDa, and the electronic conductivity at 25℃ is ≥3.5mS / cm; the Young's modulus of the positive electrode electrolyte material at 25℃ is in the range of 5GPa to 100GPa.

[0401] Example 1.

[0402] 1. Preparation of carbon composite conductive polymer materials.

[0403] The carbon conductive material raw material and the conductive polymer raw material are thoroughly mixed in ethanol (as a dispersion solvent) at a certain mass ratio, and then transferred to a ball mill jar for liquid-phase ball milling at 400 rpm for 24 hours. After ball milling, the mixture is vacuum dried at 80°C to completely remove the ethanol, thus obtaining the carbon composite conductive polymer material.

[0404] In this example, the carbon conductive material is vapor-grown carbon fiber (VGCF), and the conductive polymer is polyaniline. The mass ratio of the carbon conductive material to the conductive polymer material (R...) is... 12 The percentage is 0.5%.

[0405] In this example, the maximum particle size distribution range of the carbon conductive material raw material VGCF is 50 nm to 0.3 μm, and the specific surface area within the 50 nm to 0.3 μm range is 2000 m². 2 / g, at 1200m 2 / g~3000m 2 / g, electronic conductivity at 25℃ is approximately 10 6 mS / cm; the weight-average molecular weight of the conductive polymer raw material polyaniline is about 150kDa, and its electronic conductivity at 25℃ is about 10mS / cm in the range of 50kDa to 200kDa.

[0406] Among them, the mass ratio of carbon conductive material raw material to conductive polymer raw material (R) 12 The mass percentage (R) of carbon conductive material relative to the conductive polymer in carbon composite conductive polymer materials. 10 They are basically equal.

[0407] 2. Preparation of composite coated cathode materials (as cathode active materials)

[0408] The carbon composite conductive polymer material and the positive electrode active material were mixed by dry ball milling at a certain mass ratio of 400 rpm for 24 hours to prepare the composite coated positive electrode material.

[0409] The mass ratio of carbon composite conductive polymer material to positive electrode active bulk material (R) 20 According to the target product of the composite-coated cathode material, the mass percentage (F) of the carbon composite conductive polymer material in the composite-coated cathode material is... 10 Select the appropriate mass ratio.

[0410] In this example, the positive electrode active bulk material is NCM. 811 (LiNi 0.8 Co 0.1 Mn 0.1 O2), the mass ratio of carbon composite conductive polymer material to positive electrode active bulk material R 20 It is 0.5% (corresponding to F) 10 Approximately 0.498%. In this example, F 10 The mass percentage of the coating layer in the composite coated cathode material (F) M The sum of the mass percentages of carbon conductive materials and conductive polymers in the composite-coated cathode material (F) 20 The mass percentages of carbon conductive material in the coating layer relative to the conductive polymer (R) are essentially equal. 11 ) and R 10 They are basically equal.

[0411] 3. Preparation of positive electrode sheet

[0412] A dry method was used for preparation. The prepared composite-coated cathode material was used as the cathode active material.

[0413] The positive electrode active material, sulfide-based solid electrolyte Li6PS5Cl conductive agent (vapor-grown carbon fiber (VGCF)), and binder (polytetrafluoroethylene (PTFE)) were mixed evenly in a mass ratio of 70:28:1:1 and rolled into a positive electrode sheet. The positive electrode surface capacity was 3 mAh / cm². 2 .

[0414] The Young's modulus of the positive electrode electrolyte material Li6PS5Cl at 25℃ is approximately 20 GPa, which is in the range of 10 GPa to 50 GPa.

[0415] 4. Negative electrode plate

[0416] A lithium-indium alloy sheet is used, wherein the molar ratio of Li to In is 1:3.

[0417] 5. Assemble solid-state batteries, which are all-solid-state lithium-ion secondary batteries.

[0418] In a molded battery system, the positive electrode sheet, the raw material layer of solid electrolyte material (Li6PS5Cl), and the negative electrode sheet are placed in the order of positive electrode layer, solid electrolyte layer, and negative electrode layer from top to bottom, and then pressed into a solid-state battery under a pressure of 100MPa. The battery is then encapsulated in a molded battery fixture with an external pressure of 50MPa for performance testing.

[0419] Examples 1-8. Carbon composite conductive polymer materials, composite-coated cathode materials (as cathode active materials), cathode sheets, and solid-state batteries were prepared using essentially the same method as in Example 1. The difference lies in changing the mass ratio (R0) of the carbon conductive material raw material to the conductive polymer raw material. 12 The mass ratio (R) of carbon composite conductive polymer material to positive electrode active bulk material 20 One or both of these methods can be used to prepare the positive electrode sheet using different composite coating positive electrode materials, with the remaining operation steps being the same as in Example 1. See Table 1 for details.

[0420] In Example 5, R 12 It is 2%, R 20 It is 2% (corresponding to F) 10 (Approximately 1.96%).

[0421] Examples 9-10. Carbon composite conductive polymer materials, composite coated cathode materials (as cathode active materials), cathode plates, and solid-state batteries were prepared using the same method as in Example 5. The difference was that one or both of the types of carbon conductive material raw materials and conductive polymer raw materials were changed, and different carbon composite conductive polymer materials were used to prepare composite coated cathode materials. The remaining operation steps were the same as in Example 1.

[0422] The conductive polymer used in Example 9 is polyphenylene acetylene, with a weight-average molecular weight of approximately 2500 kDa and an electronic conductivity of approximately 50 mS / cm at 25°C.

[0423] Example 10 uses carbon nanotubes as the conductive material, with a maximum diameter ranging from 2 nm to 30 nm (the maximum diameter of the carbon nanotube is measured by its outer diameter), an average diameter of approximately 16 nm, and a specific surface area of ​​2500 m². 2 / g, electronic conductivity at 25℃ is approximately 10 8 mS / cm; the conductive polymer is polypyrrole, with a weight-average molecular weight of approximately 70 kDa, and an electronic conductivity of approximately 10 at 25°C in the range of 50 kDa to 200 kDa. 5 mS / cm.

[0424] Examples 11-12. Carbon composite conductive polymer materials, composite coated cathode materials (as cathode active materials), cathode sheets, and solid-state batteries were prepared using essentially the same method as in Example 5. The difference was that the weight-average molecular weight of the conductive polymer raw materials was changed, and different carbon composite conductive polymer materials were used to prepare the composite coated cathode materials. The remaining operation steps were the same as in Example 1. See Table 1 for details.

[0425] Examples 13-14. Carbon composite conductive polymer materials, composite coated cathode materials (as cathode active materials), cathode sheets, and solid-state batteries were prepared using essentially the same method as in Example 5. The difference was that the maximum particle size distribution range of the carbon conductive material raw materials was changed, and different carbon composite conductive polymer materials were used to prepare the composite coated cathode materials. The remaining operation steps were the same as in Example 1. See Table 1 for details.

[0426] Example 15. A carbon composite conductive polymer material, a composite coated cathode material (as the cathode active material), a cathode sheet, and a solid-state battery were prepared using a method essentially the same as in Example 5. The difference was that the method for preparing the carbon composite conductive polymer material was different. The carbon conductive material raw material, the conductive polymer raw material, and the cathode active material were directly mixed at the same mass ratio as in Example 1, and a cathode sheet was prepared using a different composite coated cathode material.

[0427] The carbon conductive material raw material, the conductive polymer raw material and the positive electrode active body material were mixed by dry ball milling at 400 rpm for 24 hours to prepare the composite coated positive electrode material.

[0428] Example 16. Using the same carbon composite conductive polymer material as in Example 5, composite coated cathode material (as cathode active material), cathode sheet and solid battery were prepared using the same method as in Example 5. The difference was that the method for preparing the composite coated cathode material was different. After ball milling, the cathode sheet was heated at 150°C for 2 hours in a flowing argon atmosphere and different composite coated cathode materials were used to prepare the cathode sheet.

[0429] The carbon composite conductive polymer material and the positive electrode active material were mixed by dry ball milling at a certain mass ratio of 400 rpm for 24 hours, and then heated at 150°C for 2 hours under a flowing argon atmosphere to prepare the composite coated positive electrode material.

[0430] Comparative Example 1. No coating layer

[0431] The positive electrode active bulk material NCM used in Example 1 811 The positive electrode and solid-state battery were prepared using it as the positive electrode active material. The remaining operation steps were the same as in Example 1.

[0432] Comparative Example 2. The coating layer contains only carbon conductive material VGCF

[0433] In the step of preparing the composite coated cathode material, the VGCF raw material of Example 1 and the cathode active bulk material NCM are used. 811 Physical coating was performed to prepare VGCF-coated NCM. 811 Using this material as the positive electrode active material, a positive electrode sheet and a solid-state battery were prepared by means of Example 1.

[0434] The carbon conductive material VGCF and the positive electrode active bulk material NCM are mixed at a mass ratio of 1%:1. 811 Dry ball milling was performed at 400 rpm for 24 hours to prepare the composite coated cathode material.

[0435] Comparative Example 3. The coating layer contains only the conductive polymer polyaniline.

[0436] In the step of preparing the composite coated cathode material, the polyaniline raw material of Example 1 and the cathode active bulk material NCM are used. 811 Physical coating was performed to prepare polyaniline-coated NCM. 811 Using this material as the positive electrode active material, a positive electrode sheet and a solid-state battery were prepared by means of Example 1.

[0437] The polyaniline raw material and the positive electrode active material NCM were mixed at a mass ratio of 2%:1. 811 Dry ball milling was performed at 400 rpm for 24 hours to prepare the composite coated cathode material.

[0438] Comparative Example 4: First, carbon conductive material VGCF is coated, and then polyaniline is coated, which is a double coating layer, with VGCF as the inner layer and polyaniline as the outer layer.

[0439] The conductive polymer raw material (polyaniline) in Example 1 was used to compare the VGCF-coated NCM prepared in Comparative Example 2. 811 The material was further coated using a dry coating method, with ball milling at 400 rpm for 24 hours to prepare a double-layer coated product A; wherein, the polyaniline raw material is relatively different from the positive electrode active bulk material NCM. 811 The mass ratio is 2%:1.

[0440] Using the double-layer coated product A as the positive electrode active material, a positive electrode sheet and a solid-state battery were prepared using the method of Example 1.

[0441] Comparative Example 5: First, polyaniline is coated, then VGCF is coated, which is a double coating layer, with polyaniline as the inner layer and VGCF as the outer layer.

[0442] The conductive polymer raw material (polyaniline) and the positive electrode active material NCM from Example 1 were mixed at a mass ratio of 2%:1. 811 The mixture was thoroughly stirred in a dispersion solvent (methanol), then transferred to a ball mill jar for liquid-phase ball milling at 400 rpm for 24 hours. After ball milling, the mixture was vacuum dried at 120°C to completely remove the dispersion solvent, yielding polyaniline-coated NCM. 811 Material.

[0443] The VGCF raw material from Example 1 was combined with polyaniline-coated NCM. 811 The materials were dry ball-milled at 400 rpm for 24 hours to prepare a double-layer coated product B. The VGCF raw material was used in relation to the positive electrode active bulk material NCM. 811 The mass ratio is 1%:1.

[0444] Using the double-layer coated product B as the positive electrode active material, a positive electrode sheet and a solid-state battery were prepared using the method of Example 1.

[0445] The relevant parameters for preparing composite coated cathode materials in Examples 1-16 can be found in Table 1.

[0446] II. Test and Analysis Methods

[0447] (I) Observation and testing of the coating layer

[0448] (1) Method to confirm successful coverage.

[0449] Method: The presence of a coating layer on the surface of the cathode particles was observed under high-resolution TEM combined with EDS.

[0450] (2) Average thickness of the coating layer of the composite coated cathode material (D1).

[0451] Instrument: High-resolution transmission electron microscope (HR TEM), model Thermo Scientific-Talos F200S G2.

[0452] Test method: The composite-coated cathode material particles were cut using an ion beam polisher (Hitachi-IM 5000), and the resulting cross-sections were subjected to HRTEM testing. Based on the boundary at the coating interface, the bulk cathode active phase and the coating layer can be distinguished.

[0453] Statistical analysis method: The average thickness of multiple test locations within each particle is recorded as the coating thickness of that particle. The average coating thickness of multiple particles is taken as the average coating thickness (D1) of the composite coated cathode material. The number of composite coated cathode material particles counted is ≥5. The number of statistical locations within each particle is ≥3.

[0454] (3) Coverage F A (Percentage of the area covered by the coating layer on the particle surface of the composite coated cathode material)

[0455] Method: Using TEM combined with EDS, the area S1 occupied by the active bulk element of the positive electrode and the area S2 occupied by the characteristic elements of the coating material were determined. The ratio of S2 to S1 is the coating degree F. A .

[0456] (II) Battery Performance Testing

[0457] The full battery underwent charge-discharge testing on the Blue Battery testing platform: test temperature 25℃; charge-discharge voltage range: 2.6~4.3V vs. Li + / Li, external pressure during testing: 50MPa.

[0458] The test procedure is as follows: After three 0.1C charge-discharge cycles of the full battery (each cycle charging to 4.3V at 0.1C and then discharging to 2.6V at 0.1C), a long-cycle 0.33C charge-discharge test is performed, with each cycle charging to 4.3V at 0.33C and then discharging to 2.6V at 0.33C, recorded as cycles 4, ... n. By collecting and processing the 0.1C charge-discharge data of the first cycle, the 0.1C charging specific capacity and discharging specific capacity can be obtained. The initial coulombic efficiency is obtained based on the ratio of the discharging specific capacity to the charging specific capacity. The capacity retention P at the 200th cycle at 0.33C rate is obtained by dividing the discharging specific capacity of cycle 203 by the discharging specific capacity of cycle 4. 200 .

[0459] The test results were recorded as “0.1C first-cycle charge specific capacity”, “0.1C first-cycle discharge specific capacity”, “0.1C first-cycle coulombic efficiency”, and “capacity retention rate after 200 cycles at 25℃ and 0.33C”.

[0460] III. Test Result Analysis

[0461] The test results can be found in Table 2.

[0462] The solid-state batteries prepared in Examples 1-16 all exhibited significantly improved cycle performance, with the capacity retention rate after 200 cycles at 25°C and 0.33C showing a significant improvement compared to Comparative Example 1. In the solid-state battery of Comparative Example 1, the positive electrode active material had no coating layer. Furthermore, the discharge capacity of the solid-state batteries prepared in Examples 1-16 also showed varying degrees of improvement compared to Comparative Example 1.

[0463] The solid-state batteries prepared in Examples 1-16 can significantly improve cycle performance while also exhibiting high initial coulombic efficiency.

[0464] In the coating layers of the composite coated cathode materials prepared in Examples 1-14 and 16, carbon conductive material is uniformly dispersed in the polymer matrix formed by the conductive polymer.

[0465] Compared to Example 15, the composite coated cathode material prepared in Example 5 exhibits better uniformity in the distribution of carbon conductive material within the polymer matrix formed by the conductive polymer in the coating layer.

[0466] In Comparative Example 2, the coating layer omits the conductive polymer and only uses carbon conductive material; in Comparative Example 3, the coating layer omits the carbon conductive material and only uses conductive polymer; in Comparative Example 4, a double-layer coating layer is used, first coating VGCF and then coating polyaniline; in Comparative Example 5, a double-layer coating layer is used, first coating polyaniline and then coating VGCF; the cycle performance of the solid-state battery in Example 1 is significantly better than that in Comparative Examples 2-5.

[0467] Table 1.

[0468]

[0469] In Table 1, R12 is the mass ratio of carbon conductive material to conductive polymer material, and R20 is the mass ratio of carbon composite conductive polymer material to positive electrode active body material.

[0470] Table 2.

[0471]

[0472] In Table 2, in Examples 4-7 and 9-14, the average thickness of the coating layer is in the range of 30nm to 40nm, and the coating degree FA is in the range of 85% to 95%.

[0473] The descriptions of the various implementation methods and embodiments above tend to emphasize the differences between them. Similarities or resemblances can be referenced interchangeably, and for the sake of brevity, they will not be repeated here. The technical features of the implementation methods and embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combinations of these technical features do not contradict each other, they should be considered within the scope of this specification.

[0474] It should be noted that this application is not limited to the above-described embodiments and examples. The above-described embodiments and examples are merely examples, and any embodiments and examples that have the same structure and achieve the same effect as the technical concept within the scope of this application are included in the technical scope of this application. The embodiments and examples described above only illustrate several embodiments and examples of this application, and although the descriptions are relatively detailed, they should not be construed as limiting the scope of the patent. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments or examples, and other ways of constructing embodiments or examples by combining some of the constituent elements of the embodiments or examples, are also included in the scope of this application without departing from the spirit of this application.

Claims

1. A solid-state battery, characterized by, The device includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially. The positive electrode layer includes a positive electrode active layer, which includes a positive electrode active material. The positive electrode active material includes a composite coated positive electrode material, which includes a positive electrode active body and a coating layer located on the surface of the positive electrode active body. The coating layer includes a carbon conductive material and a conductive polymer.

2. The solid-state battery of claim 1, wherein, At least a portion of the carbon conductive material and the conductive polymer exist as a carbon composite conductive polymer material; in the carbon composite conductive polymer material, the carbon conductive material is dispersed in a polymer matrix formed by the conductive polymer.

3. The solid-state battery of claim 2, wherein, The carbon composite conductive polymer material satisfies one or more of the following characteristics: (t1) In the carbon composite conductive polymer material, the mass percentage of the carbon conductive substance relative to the conductive polymer is 0.5% to 10%; (t2) The carbon composite conductive polymer material in the coating layer has a mass percentage of 80% to 100%; (t3) The carbon composite conductive polymer material in the composite coated cathode material has a mass percentage of 0.45% to 10%, and can be selected as 1% to 5%.

4. The solid-state battery of claim 2, wherein, The carbon composite conductive polymer material satisfies one or more of the following characteristics: (t1') In the carbon composite conductive polymer material, the mass percentage of the carbon conductive substance relative to the conductive polymer is 0.5% to 5%, optionally 0.5% to 2.5%; (t2') The carbon composite conductive polymer material in the coating layer has a mass percentage of 90% to 100%; (t3') The carbon composite conductive polymer material in the composite coated cathode material has a mass percentage of 1% to 3%.

5. The solid-state battery according to any one of claims 1 to 4, characterized by In at least a portion of the composite coated cathode material, the coating layer is located on a portion of the surface of the cathode active body.

6. The solid-state battery of claim 5, wherein, The coating layer covers 80% to 98% of the surface area of ​​the composite coated cathode material particles.

7. The solid-state battery according to claim 5, characterized in that, The coating layer covers 85% to 95% of the surface area of ​​the composite coated cathode material particles, and can be selected as 85% to 90%.

8. The solid-state battery according to any one of claims 1 to 7, characterized by, The conductive polymer satisfies one or more of the following characteristics: (a1) The weight-average molecular weight of the conductive polymer is 10 kDa to 3000 kDa; (a2) The conductive polymer includes one or more polymers selected from polyaniline, polyacetylene, polypyrrole, polythiophene, polyphenylacetylene, polyphenylene sulfide, polyfuran, polyquinoline and polycarboxylic acid, as well as one or more derivatives of any of the aforementioned polymers; the derivatives are conductive polymers; (a3) The conductive polymer has an electronic conductivity at 25°C greater than or equal to 3.5 mS / cm.

9. The solid-state battery of claim 8, wherein, The conductive polymer satisfies one or more of the following characteristics: (a1') The weight-average molecular weight of the conductive polymer is 10kDa to 1000kDa, and can be selected as 50kDa to 200kDa; (a2') The conductive polymer includes one or more of polyaniline and polyaniline derivatives; (a3') the electronic conductivity of the conductive polymer at 25°C is 3.5 mS / cm to 1.5 x 10 5 mS / cm, optionally 4 mS / cm to 10000 mS / cm.

10. The solid-state battery according to any one of claims 1 to 9, characterized in that, The carbon conductive material satisfies one or more of the following characteristics: (b1) The carbon conductive material includes one or more of carbon nanofibers, carbon nanotubes, graphite, carbon black, carbon dots, graphene, Ketjen black and fullerene. (b2) The maximum particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected from 2 nm to 0.5 μm; the maximum particle size refers to the maximum diameter among the anisotropic diameters of the particles; (b3) The average particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected as 10 nm to 0.5 μm; the average particle size refers to the average of the maximum particle size of each particle; (b4) the specific surface area of the carbon conductive substance is 1200 m 2 / g ~ 3000 m 2 / g; (b5) the carbon conductive substance has an electronic conductivity at 25°C greater than or equal to 10 5 mS / cm.

11. The solid-state battery of claim 10, wherein, The carbon conductive material satisfies one or more of the following characteristics: (b1') The carbon nanofibers include vapor-grown carbon fibers; (b2') The maximum particle size of the carbon conductive material is less than or equal to 0.3 μm, and can be selected as 50 nm to 0.3 μm; (b3') The average particle size of the carbon conductive material is less than or equal to 0.3 μm, and can be selected as 50 nm to 0.3 μm; (b4') the specific surface area of the carbon conductive substance is 1800 m 2 / g ~ 2300 m 2 / g; (b5') the electronic conductivity of the carbon conductive substance at 25°C is 10 5 mS / cm ~ 1.5 x 10 8 mS / cm, optionally 10 6 mS / cm ~ 10 8 mS / cm.

12. The solid-state battery according to any one of claims 1 to 11, characterized in that, In the coating layer, the carbon conductive material has a mass percentage of 0.5% to 10% relative to the conductive polymer.

13. The solid-state battery of claim 12, wherein, In the coating layer, the carbon conductive material has a mass percentage of 0.5% to 5% relative to the conductive polymer, optionally 0.5% to 2.5%.

14. The solid-state battery according to any one of claims 1 to 13, characterized in that, The composite-coated cathode material satisfies one or more of the following characteristics: (c1) The sum of the mass percentages of the carbon conductive material and the conductive polymer in the composite coated cathode material is 0.5% to 10%, and optionally 1% to 5%; (c2) The coating layer in the composite coated cathode material has a mass percentage of 0.45% to 10%, and can be selected as 1% to 5%; (c3) The average thickness of the coating layer is 5 nm to 150 nm; (c4) At least a portion of the coating layer has a thickness of 5 nm to 120 nm; (c5) The sum of the mass percentages of the carbon conductive material and the conductive polymer in the coating layer is 90% to 100%; (c6) The composite coated cathode material accounts for 80% to 100% of the mass of the cathode active material; (c7) The electronic conductivity of the composite coated cathode material at 25°C is greater than or equal to 10 mS / cm.

15. The solid-state battery of claim 14, wherein, The composite-coated cathode material satisfies one or more of the following characteristics: (c1') The sum of the mass percentages of the carbon conductive material and the conductive polymer in the composite coated cathode material is 1% to 3%; (c2') The coating layer has a mass percentage of 1% to 3% in the composite coated cathode material; (c3') The average thickness of the coating layer is 10nm to 130nm, and can be selected as 20nm to 80nm; (c4') At least a portion of the coating layer has a thickness of 10 nm to 120 nm; (c5') The sum of the mass percentages of the carbon conductive material and the conductive polymer in the coating layer is 98% to 100%; (c6') The composite coated cathode material accounts for 90% to 100% of the mass of the cathode active material.

16. The solid-state battery according to any one of claims 1 to 15, characterized in that, In the positive electrode active layer, the mass percentage of the blended conductive agent is 0-3%; the blended conductive agent refers to different particles located outside the particles of the composite coated positive electrode material.

17. The solid-state battery of claim 16, wherein, In the positive electrode active layer, the mass percentage of the blended conductive agent is 0-1.5%.

18. The solid-state battery of any one of claims 1-17, wherein, The positive electrode active layer further includes a positive electrode electrolyte material, which satisfies one or more of the following characteristics: (d1) The Young's modulus of the positive electrode electrolyte material at 25°C is 5 GPa to 100 GPa; (d2) The positive electrode electrolyte material includes one or more of the following: sulfide solid electrolyte, halide solid electrolyte, halide oxide solid electrolyte, and polymer electrolyte.

19. The solid-state battery of claim 18, wherein, The positive electrode electrolyte material satisfies one or more of the following characteristics: (d1') The Young's modulus of the positive electrode electrolyte material at 25°C is 10 GPa to 50 GPa; (d2') The positive electrode electrolyte material includes sulfide solid electrolytes.

20. The solid-state battery of any one of claims 1-19, wherein, The composite-coated cathode material satisfies one or more of the following characteristics: (e1) The positive electrode active body includes one or more of disordered rock salt phase positive electrode materials, spinel phase positive electrode materials and lithium titanate; (e2) The positive electrode active body includes one or more of lithium nickel cobalt manganese-based oxides, lithium nickel cobalt aluminum-based oxides, lithium cobalt oxide, chalcogenide positive electrode active materials, lithium manganese oxide, lithium nickel oxide, and lithium-rich manganese-based positive electrode active materials.

21. The solid-state battery according to any one of claims 1 to 20, characterized in that, The composite-coated cathode material satisfies one or more of the following characteristics: (e1') The positive electrode active body includes one or more of disordered rock salt phase positive electrode and spinel phase positive electrode; (e2') The positive electrode active body includes one or more of lithium nickel cobalt manganese-based oxides, lithium cobalt oxide, and chalcogenide positive electrode active materials.

22. The solid-state battery according to any one of claims 1 to 21, characterized in that, It meets one or more of the following characteristics: (i1) The solid-state battery is an all-solid-state battery; (i2) The solid-state battery is a lithium-ion secondary battery.

23. The solid-state battery according to claim 22, characterized in that, The solid-state battery is an all-solid-state lithium-ion secondary battery.

24. A method for preparing a solid-state battery, characterized in that, The process includes the following steps: stacking the positive electrode, solid electrolyte material layer, and negative electrode in sequence, pressing them together, and preparing a solid-state battery. The positive electrode sheet includes a positive active layer, which includes a composite coated positive electrode material. The composite coated positive electrode material includes a positive active body and a coating layer located on the surface of the positive active body. The coating layer includes a carbon conductive material and a conductive polymer.

25. The method for preparing a solid-state battery according to claim 24, characterized in that, The positive electrode active layer includes the features of the positive electrode active layer in the solid-state battery as described in any one of claims 2 to 23.

26. The method for preparing a solid-state battery according to claim 24 or 25, characterized in that, The composite-coated cathode material is prepared by a method comprising the following steps: A carbon composite conductive polymer material and a positive electrode active bulk material are dry-ball-milled and then heated under a flowing inert atmosphere to prepare the composite-coated positive electrode material. The carbon composite conductive polymer material comprises a polymer matrix formed by the conductive polymer and a carbon conductive substance dispersed within the polymer matrix. The heating temperature is denoted as T1, the glass transition temperature of the conductive polymer is denoted as Tg1, and the thermal decomposition temperature of the conductive polymer is denoted as Td1, satisfying Tg1. <T1<Td1。 27. The method for preparing a solid-state battery according to claim 26, characterized in that, It meets one or more of the following characteristics: (f1)Tg1+5℃≤T1≤Td1-5℃; (f2) The temperature for performing the heat treatment is 100℃~200℃; (f3) The duration of the heat treatment is 60 min to 360 min; (f4) The flowing inert atmosphere includes one or more of argon and nitrogen; (f5) The rotation speed for the dry ball milling mixture is 300 rpm to 600 rpm; (f6) The ball milling time for the dry ball milling mixture is 12h to 36h; (f7) The carbon composite conductive polymer material is prepared by a method comprising the following steps: mixing carbon conductive material raw material and conductive polymer raw material in a dispersion solvent, performing liquid-phase ball milling, and drying to remove the dispersion solvent to obtain the carbon composite conductive polymer material; optionally, the dispersion solvent includes one or more of ethanol, toluene, methanol and diethyl ether; optionally, the rotation speed of the liquid-phase ball milling is 300 rpm to 600 rpm, and the ball milling time is 12 h to 36 h; (f8) The positive electrode sheet is prepared by a method comprising the following steps: mixing a positive electrode material composition comprising the composite coated positive electrode material and the positive electrode electrolyte material, and forming a membrane under solvent-free conditions; wherein, the positive electrode material composition may optionally include a binder; (f9) Prepare the solid-state battery as described in any one of claims 1 to 20.

28. An electrical appliance, characterized in that, It includes at least one of the solid-state batteries described in any one of claims 1 to 23 and solid-state batteries prepared by the method described in any one of claims 24 to 27.

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