Silicon-containing negative electrode material, preparation method of coated silicon-based material, negative electrode film, solid-state battery and electric device

Abstract

The invention relates to a silicon-containing negative electrode material, a preparation method of a coated silicon-based material, a negative electrode film, a solid-state battery and an electric device. The silicon-containing negative electrode material comprises a coated silicon-based material, wherein the coated silicon-based material comprises a silicon-based body and an electrolyte coating layer coating at least one part of the surface of the silicon-based body; the electrolyte coating layer contains a sulfide solid electrolyte. The solid-state battery prepared from the silicon-containing negative electrode material has excellent comprehensive performance in the aspects of discharge capacity, rate capability and cycle performance.

Description

Technical Field

[0001] The present application relates to the field of solid-state battery technology, and further to silicon-containing negative electrode materials, methods for preparing coated silicon-based materials, negative electrode films, solid-state batteries, and electrical devices. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] Solid-state batteries introduce non-flammable solid electrolytes to replace the organic electrolytes in traditional liquid secondary batteries, significantly improving battery safety. Comprehensively improving the discharge capacity, rate capability, and cycle performance of solid-state batteries is of great significance for promoting the industrialization of solid-state batteries. Summary of the Invention

[0004] In view of the above problems, according to various embodiments and examples of the present application, the present application provides a silicon-containing negative electrode material, a method for preparing a coated silicon-based material, a negative electrode film, a solid-state battery, and an electrical device. The silicon-containing negative electrode material includes a coated silicon-based material, and a solid-state battery prepared using the silicon-containing negative electrode material has excellent comprehensive performance in terms of discharge capacity, rate performance, and cycle performance.

[0005] In a first aspect of the present application, a silicon-containing negative electrode material is provided, which includes a coated silicon-based material, wherein the coated silicon-based material includes a silicon base body and an electrolyte coating layer coated on at least a portion of the surface of the silicon base body; the electrolyte coating layer contains a sulfide solid electrolyte.

[0006] In some embodiments, a silicon-containing negative electrode material is provided, which includes a coated silicon-based material, wherein the coated silicon-based material includes a silicon base body and an electrolyte coating layer coated on at least a portion of the surface of the silicon base body; the electrolyte coating layer contains a sulfide solid electrolyte.

[0007] In some embodiments, a silicon-containing negative electrode material is provided, which includes a coated silicon-based material, wherein the coated silicon-based material includes a silicon base body and an electrolyte coating layer coated on at least a portion of the surface of the silicon base body; the electrolyte coating layer includes a sulfide solid electrolyte;

[0008] Wherein, in the coated silicon-based material, under the test condition of 20°C, the ionic conductivity of the sulfide solid electrolyte is greater than or equal to 0.1 mS / cm, and under the test condition of 30°C, the ratio of the Young's modulus of the sulfide solid electrolyte to the silicon base body is less than 1;

[0009] Optionally, under test conditions at 20° C., the ionic conductivity of the sulfide solid electrolyte is greater than or equal to 0.5 mS / cm; further optionally, under test conditions at 20° C., the ionic conductivity of the sulfide solid electrolyte is greater than or equal to 1 mS / cm;

[0010] Optionally, under test conditions at 30° C., a ratio of the Young's modulus of the sulfide solid electrolyte to that of the silicon matrix is ​​less than or equal to 0.8.

[0011] In some embodiments, the sulfide solid electrolyte comprises a Li2S–SiS2–P2S5 ternary sulfide electrolyte;

[0012] Optionally, in the Li2S–SiS2–P2S5 ternary sulfide electrolyte, the atomic molar ratio of Li element to Si element is denoted as R Li / Si The atomic molar ratio of P element to Si element is denoted as R P / Si , 1.80 <R Li / Si <1.84, 10.34 <R P / Si <0.38;

[0013] Further optionally, the Li2S-SiS2-P2S5 ternary sulfide electrolyte includes Li 1.82 SiP 0.036 S3.

[0014] In the coated silicon-based material containing silicon negative electrode materials, a sulfide solid electrolyte with high ionic conductivity (which can be recorded as a first sulfide solid electrolyte) is used to coat the silicon base body, and an electrolyte coating layer is provided on the surface of the silicon base body. When it is used to prepare a solid-state battery, it is beneficial to the conduction of active ions between the particles of the silicon-based material, reducing impedance, and helping to give full play to the capacity of the silicon-containing negative electrode material, which can improve the rate performance and cycle performance of the solid-state battery. Moreover, the material of the aforementioned electrolyte coating layer is softer than that of the silicon base body, which is beneficial to alleviating the adverse effects of the volume expansion of the silicon-based material on the interface contact, improving the stability of ion transmission in the negative electrode layer, and helping to improve the cycle stability of the battery.

[0015] In some embodiments, the silicon matrix includes one or more of elemental silicon, a silicon-carbon composite, a silicon oxide, and a silicon-carbon composite;

[0016] Optionally, the silicon matrix includes a silicon-carbon composite, and the silicon-carbon composite includes a porous carbon matrix and nano-silicon located in the pores of the porous carbon matrix.

[0017] Silicon-based materials can be flexibly selected. Among them, silicon-carbon composites have the following advantages: nano-silicon is located in a porous carbon matrix, which can more effectively inhibit the expansion of silicon and is more conducive to improving the cycle life of the battery.

[0018] In some embodiments, the coated silicon-based material satisfies one or more of the following characteristics:

[0019] In the coated silicon-based material, the weight ratio of the sulfide solid electrolyte to the silicon base body is 1:(20-70), and can be optionally 1:(45-55);

[0020] The weight proportion of the sulfide solid electrolyte in the coated silicon-based material is 1 wt% to 5 wt%, and can be optionally 1.5 wt% to 2.5 wt%;

[0021] The thickness of the electrolyte coating layer is 1 nm to 100 nm, and can be optionally 10 nm to 50 nm.

[0022] The amount of sulfide solid electrolyte coating can be adjusted by controlling one or more of the following parameters: the weight ratio of the sulfide solid electrolyte to the silicon matrix, the weight proportion of the sulfide solid electrolyte in the coated silicon-based material, and the thickness of the electrolyte coating layer. By controlling one or more of these parameters within the aforementioned ranges, it is possible to fully utilize the effects of improving the battery's discharge capacity, rate capability, and cycle performance, while also achieving high energy density.

[0023] In some embodiments, the D of the silicon matrix v 50 or the particle size is less than or equal to 50 μm, and can be selected from 1 μm to 50 μm, further selected from 1 μm to 8 μm, and further selected from 4 μm to 6 μm.

[0024] By converting the silicon base body into v 50 is controlled within the aforementioned range, which is more conducive to the uniformity of the coating, thereby better improving the discharge capacity, rate performance and cycle performance of the battery.

[0025] In some embodiments, the electrolyte coating layer includes dot-shaped particles of the sulfide solid electrolyte;

[0026] Optionally, the particle size of the dot-shaped particles of the sulfide solid electrolyte is less than or equal to 1 μm, and can be optionally 0.1 μm to 1 μm.

[0027] When the sulfide solid electrolyte exists in the form of point-like particles on the surface of the silicon base body, it is more conducive to improving the ionic conductivity and also to improving the coating stability of the coating layer when the silicon-based material undergoes volume expansion, thereby helping to more stably optimize the electrochemical performance of the battery.

[0028] By controlling the particle size of the dot-like particles within the aforementioned range, the contact area between the electrolyte material and the silicon-based material can be adjusted, thereby further improving the transport capacity of active ions.

[0029] In some embodiments, in at least a portion of the coated silicon-based material, the sulfide solid electrolyte is distributed discontinuously on the surface of the silicon-based body.

[0030] When the sulfide solid electrolyte is distributed in a discontinuous manner on the surface of the silicon base body, it is more conducive to improving the coating stability when the silicon-based material undergoes volume expansion.

[0031] In some embodiments, the weight proportion of the coated silicon-based material in the silicon-containing negative electrode material is greater than or equal to 50 wt %, optionally 50 wt % to 99 wt %, and further optionally 85 wt % to 97 wt %.

[0032] By controlling the weight proportion of the coated silicon-based material in the silicon-containing negative electrode material within the aforementioned range, it is beneficial to better play the comprehensive role of promoting the conduction of active ions and improving the stability of the interface contact. On the one hand, it can promote the conduction of active ions between the particles of the silicon-based material, fully exert the capacity of the silicon-containing negative electrode material, and improve the rate performance and cycle performance of the solid-state battery. On the other hand, it can also effectively inhibit the adverse effects of the volume expansion of the silicon-based material on the interface contact, thereby improving the cycle stability of the battery.

[0033] In some embodiments, the silicon-containing negative electrode material further comprises or does not comprise a blended solid electrolyte;

[0034] Optionally, the blended solid electrolyte includes a blended sulfide solid electrolyte;

[0035] Further optionally, the blended solid electrolyte includes thio-LISICON, Li6PS5Cl, Li 10 SnP2S 12 , one or more of Li2S-P2S5 binary sulfur-based electrolyte, Li2S-SiS2 binary sulfur-based electrolyte and Li2S-B2S3 binary sulfur-based electrolyte.

[0036] In some embodiments, the weight percentage of the blended solid electrolyte in the silicon-containing negative electrode material is 0 wt% to 30 wt%, and can be optionally 0.5 wt% to 5 wt%.

[0037] Introducing a blended solid electrolyte into a silicon-containing anode material can improve the overall ionic conductivity of the solid-state battery's anode layer. By controlling the weight ratio of the blended solid electrolyte in the silicon-containing anode material within the aforementioned range, this can improve the overall ionic conductivity of the solid-state battery's anode layer while also achieving a higher energy density.

[0038] In some embodiments, the silicon-containing negative electrode material satisfies one or more of the following characteristics:

[0039] The silicon-containing negative electrode material may or may not include a negative electrode conductive agent; optionally, the weight proportion of the negative electrode conductive agent in the silicon-containing negative electrode material is 0 wt% to 10 wt%, optionally 0.1 wt% to 10 wt%, further optionally 0.1 wt% to 2 wt%;

[0040] The silicon-containing negative electrode material includes a negative electrode binder; optionally, the weight proportion of the negative electrode binder in the silicon-containing negative electrode material is 0.1 wt% to 20 wt%, and further optionally 1 wt% to 10 wt%.

[0041] By controlling the weight ratio of the negative electrode conductive agent in the silicon-containing negative electrode material, the overall electronic conduction and electrical contact in the negative electrode layer can be optimized, thereby improving the discharge capacity, rate performance and cycle performance of the battery.

[0042] By controlling the weight ratio of the negative electrode binder in the silicon-containing negative electrode material, the electrical contact between the active particles in the negative electrode layer can be optimized, the capacity of the negative electrode can be promoted, and the rate performance and cycle performance of the battery can be improved.

[0043] In a second aspect of the present application, a method for preparing a coated silicon-based material is provided, which can be used to prepare the coated silicon-based material described in the first aspect of the present application.

[0044] In some embodiments, a method for preparing a coated silicon-based material is provided, comprising the following steps:

[0045] The sulfide solid electrolyte is physically mixed with a silicon base body, and then sintered to form an electrolyte coating layer containing the sulfide solid electrolyte on at least a portion of the surface of the silicon base body, thereby preparing a coated silicon-based material.

[0046] In some embodiments, the sulfide solid electrolyte is as defined in the first aspect of the present application.

[0047] In some embodiments, the method for preparing the coated silicon-based material satisfies one or more of the following characteristics:

[0048] The sulfide solid electrolyte is in a granular form, and the D v 50 or particle size is less than or equal to 1 μm, which can be selected from 0.1 μm to 1 μm;

[0049] The silicon base body is in granular form, and the D v 50 is less than or equal to 50 μm, and may be 1 μm to 50 μm, further 1 μm to 8 μm, and further 4 μm to 6 μm;

[0050] In the step of physically blending the sulfide solid electrolyte with the silicon matrix, the weight ratio of the sulfide solid electrolyte to the silicon matrix is ​​1:(20-70), and can be optionally 1:(45-55);

[0051] The method for performing the physical blending is dry blending;

[0052] The sintering atmosphere for the sintering is argon;

[0053] The sintering temperature is 550°C to 650°C, and can be 580°C to 620°C.

[0054] The sintering time is 6 hours to 10 hours.

[0055] In some embodiments, the sulfide solid electrolyte is prepared by a method comprising the following steps:

[0056] The precursor raw materials of the sulfide solid electrolyte are mixed, ball-milled, and sintered in a sealed state to obtain the sulfide solid electrolyte.

[0057] In some embodiments, the method for preparing the coated silicon-based material satisfies one or more of the following characteristics:

[0058] The ball milling is performed by dry ball milling;

[0059] The ball milling beads used for the ball milling include zirconium oxide ball milling beads;

[0060] The ball milling is performed at a rotation speed of 300 rpm to 400 rpm, and can be optionally 300 rpm to 350 rpm;

[0061] The ball milling is performed for 36 to 48 hours.

[0062] In some embodiments, the coated silicon-based material is the coated silicon-based material in the silicon-containing negative electrode material described in the first aspect of the present application.

[0063] In a third aspect of the present application, a negative electrode film is provided, which includes a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector, wherein the negative electrode active material layer includes the silicon-containing negative electrode material described in the first aspect of the present application.

[0064] In some embodiments, the negative electrode film is an all-solid-state negative electrode film.

[0065] In a fourth aspect of the present application, a solid-state battery is provided, comprising the negative electrode film described in the third aspect of the present application.

[0066] In some embodiments, the solid-state battery is a sulfide all-solid-state battery.

[0067] In some embodiments, the solid-state battery is a lithium-ion solid-state battery.

[0068] In a fifth aspect of the present application, an electrical device is provided, which includes at least one of the negative electrode film described in the third aspect of the present application and the solid-state battery described in the fourth aspect of the present application.

[0069] The details of one or more embodiments or examples of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to better describe and illustrate the embodiments, examples or examples provided in this application, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered as limiting the scope of the disclosed application, the embodiments, examples or examples currently described, and any of the best modes of these applications currently understood. It should also be noted that the accompanying drawings are drawn in a simplified form and are only used to assist in the explanation of this application for convenience and clarity. The various dimensions of each component shown in the accompanying drawings are arbitrarily shown and may be accurate or not drawn to scale. For example, in order to make the illustration clearer, the dimensions of the components are appropriately exaggerated in some places in the accompanying drawings. Unless otherwise specified, the components in the drawings are not drawn to scale. The drawings of this application do not limit every dimension of each component. Moreover, the same figure numbers are used to represent the same components in all the drawings. In the drawings:

[0071] Figure 1 It is a schematic structural diagram of coated silicon particles in a silicon-containing negative electrode material provided in one embodiment of the present application. The coated silicon-based particles include a silicon base body and an electrolyte coating layer located on the surface of the silicon base body.

[0072] Figure 2 This is a schematic structural diagram of coated silicon-based particles in a silicon-containing negative electrode material provided in one embodiment of the present application. The coated silicon-based particles include a silicon base body and an electrolyte coating layer located on the surface of the silicon base body. The electrolyte coating layer contains a sulfide solid electrolyte (referred to as a first sulfide solid electrolyte or a coated sulfide solid electrolyte).

[0073] Figure 3 Schematic diagram of the structure of a negative electrode film according to one embodiment of the present application, wherein the negative electrode film includes a negative electrode current collector and a negative electrode active material layer located on one side of the negative electrode current collector.

[0074] Figure 4Schematic diagram of the structure of a negative electrode film according to one embodiment of the present application, wherein the negative electrode film includes a negative electrode current collector and negative electrode active material layers located on both sides of the negative electrode current collector.

[0075] Figure 5 This is a schematic structural diagram of a solid-state battery cell according to one embodiment of the present application, which includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked in sequence.

[0076] Figure 6 for Figure 5 A structural schematic diagram of an embodiment of a solid-state battery cell is shown, which includes a positive electrode layer, a solid electrolyte layer and a negative electrode layer stacked in sequence, wherein the negative electrode layer includes a negative electrode film according to an embodiment of the present application, the negative electrode film includes a negative electrode current collector and a negative electrode active material layer located on both sides of the negative electrode current collector, and a negative electrode active material layer is arranged between the negative electrode current collector and the solid electrolyte layer.

[0077] Figure 7 Schematic diagram of an all-solid-state battery cell according to one embodiment of the present application.

[0078] Figure 8 for Figure 7 An exploded view of an all-solid-state battery cell according to an embodiment of the present application is shown.

[0079] Figure 9 This is a schematic diagram of a battery module according to one embodiment of the present application.

[0080] Figure 10 Schematic diagram of a battery pack according to one embodiment of the present application.

[0081] Figure 11 for Figure 10 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0082] Figure 12 Schematic diagram of an electrical device using an all-solid-state battery as a power source according to one embodiment of the present application.

[0083] Description of reference numerals:

[0084] 60, coated silicon-based particles; 62, silicon-based body; 64, electrolyte coating layer; 642, coated sulfide solid electrolyte (sulfide solid electrolyte in the electrolyte coating layer, also referred to as first sulfide solid electrolyte); 300, negative electrode layer; 30, negative electrode membrane; 310, negative electrode current collector; 320, negative electrode active material layer; 100, solid electrolyte layer; 200, positive electrode layer; 1, battery pack; 2, upper case; 3, lower case; 4, battery module; 5, all-solid-state battery cell; 51, shell; 52, solid-state battery cell; 53, cover plate; 6, electrical device.

[0085] It can be understood that in the various drawings, the drawn sizes of structures such as the solid-state battery cell 52, the negative electrode film 30, the negative electrode current collector 310, the negative electrode active material layer 320, the negative electrode layer 300, the solid electrolyte layer 100, and the positive electrode layer 200 do not represent the actual sizes; the shapes and sizes of materials or local structures of materials such as the coated silicon-based particles 60, the silicon base body 62, the electrolyte coating layer 64, the coated sulfide solid electrolyte 642, etc. involved in the various drawings do not represent or are not used to limit the shapes and sizes of the actual materials, and the numbers shown in the drawings do not represent or are not used to limit the actual numbers and quantity ratios. DETAILED DESCRIPTION

[0086] Below, some embodiments of the silicon-containing negative electrode material, the preparation method of the coated silicon-based material, the negative electrode film, the solid-state battery and the electric device of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0087] " scope " disclosed in the present application can be limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and any end value can be included or not included independently, and can be arbitrarily combined, that is, any lower limit can form a scope with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3,4 and 5 are also listed, then the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to listing the parameter as, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on. For example, when a parameter is expressed as an integer selected from "2-10", this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0088] In this application, unless otherwise specified, "about" means within a reasonable range above or below the number. The fluctuation range may vary depending on the type and value of the number. For example, a range of ±10%, ±5%, ±2%, ±1%, etc. may be allowed. For example, taking "about 20°C" and its approximate value of ±1°C as an example, approximate values ​​such as 19°C and 19.5°C within the approximate range of "about 20°C" should also be included in the range indicated by "about 20°C".

[0089] In this application, references to "multiple," "multiple," "multiple," "several," and the like, unless otherwise specified, refer to a quantity greater than or equal to two. For example, "one or more" means one or ≥ (greater than or equal to) two. It is understood that references to "any number" of items refer to any suitable combination of multiple items, i.e., any combination of "any number" of items that is not in conflict and that enables the implementation of this application.

[0090] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0091] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of such phrases in various locations in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. References to "implementations" herein have a similar understanding.

[0092] Those skilled in the art will appreciate that, in the methods of each embodiment or embodiment, the order in which each step is written does not mean a strict order of execution and constitutes any limitation to the implementation process, and the detailed order of execution of each step should be determined by its function and possible inherent logic. Unless otherwise specified, all steps of the present application can be performed in sequence, or can be performed randomly, or can preferably be performed in sequence. For example, method M includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, method M may also include step (c), indicating that step (c) can be added to method M in any order, for example, method M may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0093] In this application, in open technical features or technical solutions described with words such as "contain," "include," and "include," unless otherwise specified, additional members other than the listed members are not excluded, and it can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or not. It can be regarded as providing both the feature or solution of "A consists of a1, a2, and a3" or "A is selected from a1, a2, and a3", and the feature or solution of "A includes not only a1, a2, and a3, but also other members."

[0094] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0095] In this application, "optionally," "optional," and "optional" mean optional, that is, they refer to either option selected from the two parallel options of "yes" or "no." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" is independent. Unless otherwise specified, the descriptions "optionally include," "optionally include," etc. in this application, using "optionally include" as an example, mean "may include or not include."

[0096] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more relevant listed items, and also include any and all combinations of the relevant listed items, wherein any and all combinations include any two relevant listed items, any more relevant listed items, or a combination of all relevant listed items. For example, "A and / or B" means a group consisting of A, B, and "a combination of A and B." Among them, "including A and / or B" can mean "including A, including B, and including A and B", and can also mean "including A, including B, or including A and B", which can be appropriately understood according to the sentence in which it is used.

[0097] As used herein, "combination thereof", "any combination thereof", "any combination thereof" and the like include all suitable combinations of any two or more of the listed items.

[0098] Herein, the word “suitable” in “suitable combination”, “suitable method”, “any suitable method”, etc., shall be based on the technical solution that can implement the present application.

[0099] Herein, the terms "preferred," "better," "more preferable," "suitable," "comparatively better," and "preferable" are used solely to describe preferred implementations or examples and should not be construed as limiting the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, each "preferred" term is considered independent unless otherwise specified and there are no contradictions or mutual constraints.

[0100] In this application, "further", "further", "particularly", "for example", "such as", "example", "for example", etc. are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0101] In this application, the terms "first," "second," "third," "fourth," "fifth," "first sulfide solid electrolyte," "second sulfide solid electrolyte," etc., are used for descriptive purposes only and should not be understood as indicating or implying relative importance or quantity, nor should they be understood as implicitly indicating the importance or quantity of the technical features indicated. Furthermore, "first," "second," "third," "fourth," "fifth," etc., are only used for non-exhaustive enumeration and description purposes and should be understood not to constitute a closed limitation on quantity.

[0102] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may refer to a relative horizontal positional relationship, or may simply refer to an attachment relationship without limiting the relative horizontal positional relationship.

[0103] In this application, the term "room temperature" generally refers to 4°C to 35°C, and may refer to 20°C ± 5°C. In some embodiments or examples of this application, room temperature refers to 20°C to 30°C.

[0104] In this application, when referring to a data range, if the unit is followed only by the right endpoint, it means that the units of the left and right endpoints are the same. For example, "3~5h" or "3-5h" both mean that the units of the left endpoint "3" and the right endpoint "5" are both hours, and both have the same meaning as "3h~5h". Similarly, descriptions of other parameters such as temperature and size are to be understood in the same manner.

[0105] The weight or mass of the relevant components mentioned in the embodiments or examples of the present application can not only refer to the content of each component, but also represent the proportional relationship of weight or mass between each component. Therefore, as long as the content of the relevant components in accordance with the embodiments or examples of the present application is proportionally enlarged or reduced, it is within the scope described in the present application. Further, the mass involved in the embodiments or examples of the present application can be mass units known to the chemical industry such as micrograms (μg), milligrams (mg), grams (g), kilograms (kg). Unless otherwise specified, the mass ratio is equal to the corresponding weight ratio, such as the mass of substance A is m1 and the weight is W1, the mass of substance B is m2 and the weight is W2, then the mass ratio m1 / m2 of the two is numerically equal to the corresponding weight ratio W1 / W2.

[0106] In this application, unless otherwise specified, wt% represents weight percentage by weight and is numerically equivalent to the corresponding mass percentage by mass. In this application, when a weight percentage is represented by "0", it has the same meaning as "0wt%" and can be used interchangeably.

[0107] The units of parameters involved in this application, unless otherwise specified, are nm for nanometers, μm for micrometers, S / cm for Siemens per centimeter, V for volts, mPa·S for millipascals per second, and mg / cm 2 Expressed in milligrams per square centimeter, g / cm 2 Indicates grams per square centimeter, g / cm 3 represents grams per cubic centimeter, ℃ represents degrees Celsius, and mA / g represents milliamperes per gram.

[0108] In this application, "greater than or equal to", "greater than or equal to", and "≥" have the same meaning and can be used interchangeably; "less than or equal to", "less than or equal to", and "≤" have the same meaning and can be used interchangeably; "greater than" can be equivalently expressed as ">", and "less than" can be equivalently expressed as "<". In this application, unless otherwise specified, "greater than or equal to" and "≥" can be regarded as providing two solutions of "greater than" and "equal to". In this application, unless otherwise specified, "less than or equal to" and "≤" can be regarded as providing two solutions of "less than" and "equal to".

[0109] In this application, exemplary descriptions such as "in some embodiments (or examples)" and "in one embodiment (or example)" may include 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.

[0110] In this application, unless otherwise specified, the "solid-state battery" provided in this application refers to a battery in which the electrolyte in the battery includes a solid electrolyte; generally, a solid-state battery includes a positive electrode layer, a solid electrolyte layer and a negative electrode layer. During the charge and discharge process of the battery, active ions are embedded and released back and forth between the positive electrode layer and the negative electrode layer. The solid electrolyte layer plays the role of conducting ions between the positive electrode layer and the negative electrode layer, and can also isolate the positive electrode layer from the negative electrode layer to prevent the positive and negative electrodes from short-circuiting. Therefore, the isolation membrane in the traditional lithium-ion battery can be omitted in the solid-state battery. The solid-state battery introduces a non-flammable solid electrolyte to replace the organic electrolyte in the traditional liquid lithium-ion battery, which greatly improves the safety of the battery. In addition to improving safety, solid-state batteries can better adapt to high-energy-density positive and negative electrode materials and reduce the weight of the system, which is conducive to taking into account the improvement of energy density.

[0111] In this application, unless otherwise specified, "solid electrolyte" refers to an electrolyte material or substance that exists in a solid form during the storage and preparation of a solid-state battery and its components, as well as during the operation of the solid-state battery. It is understood that the solid electrolyte exists in a solid form, including but not limited to, at room temperature.

[0112] In this application, unless otherwise specified, the electrode layer can be a positive electrode layer or a negative electrode layer, and the "active material" in the electrode layer refers to a substance that can reversibly embed and release active ions. Unless otherwise specified, "negative electrode active material" refers to a substance used in the negative electrode layer that can reversibly embed and release active ions; "positive electrode active material" refers to a substance used in the positive electrode layer that can reversibly release and embed active ions. When the solid-state battery is charging, the active ions are released from the positive electrode and embedded in the negative electrode through the solid electrolyte layer; when the solid-state battery is discharging, the active ions are released from the negative electrode and embedded in the positive electrode. The active ions are not particularly limited and are non-restrictive. The active ions can be lithium ions, which corresponds to a lithium-ion solid-state battery.

[0113] In this application, "electrode active material", "electrode active substance", "active material" and "active substance" have the same meaning and can be used interchangeably; "positive electrode active substance" and "positive electrode active material" have the same meaning and can be used interchangeably; "negative electrode active substance" and "negative electrode active material" have the same meaning and can be used interchangeably. "Positive electrode active substance" and "positive electrode active material" have the same meaning and can be used interchangeably; "negative electrode active substance" and "negative electrode active material" have the same meaning and can be used interchangeably.

[0114] In this application, unless otherwise specified, the term "electrode active material layer" includes at least one of the positive electrode active material layer in the positive electrode layer and the negative electrode active material layer in the negative electrode layer. Depending on the specific circumstances, the electrode active material layer may refer to the positive electrode active material layer or the negative electrode active material layer. It is understood that the positive electrode active material layer contains a positive electrode active substance, and the negative electrode active material layer contains a negative electrode active substance. In this application, the term "electrode active material layer" may also be referred to as the "active material layer."

[0115] In the present application, unless otherwise specified, the negative electrode layer at least includes a negative electrode active material layer.

[0116] In the present application, unless otherwise specified, the negative electrode active material layer at least includes negative electrode active particles, and may or may not include negative electrode electrolyte particles.

[0117] In this application, unless otherwise specified, “negative electrode active particles” refer to particles containing negative electrode active materials, which have the ability to reversibly embed and de-embed active ions.

[0118] In this application, unless otherwise specified, "negative electrode electrolyte particles" and "negative electrode solid electrolyte" have the same meaning and can be used interchangeably to refer to solid electrolytes that can be used in negative electrode films or negative electrode layers. Negative electrode electrolyte particles can enhance the ion conductivity of the negative electrode film or negative electrode layer and reduce interfacial impedance, thereby promoting the charge transfer efficiency between the negative electrode active material and the outside world and fully releasing its capacity.

[0119] In the present application, unless otherwise specified, the positive electrode layer at least includes a positive electrode active material layer.

[0120] In the present application, unless otherwise specified, the positive electrode active material layer includes at least positive electrode active particles and generally also includes positive electrode electrolyte particles.

[0121] In this application, unless otherwise specified, “positive electrode active particles” refer to particles containing positive electrode active materials, which have the ability to reversibly release and embed active ions.

[0122] In this application, unless otherwise specified, "positive electrode electrolyte particles" and "positive electrode solid electrolyte" have the same meaning and can be used interchangeably to refer to solid electrolytes that can be used in positive electrode membranes or positive electrode layers. Positive electrode electrolyte particles can enhance the ion conductivity of the positive electrode membrane or positive electrode layer and reduce interfacial impedance, thereby promoting the charge transfer efficiency between the positive electrode active material and the outside world and fully releasing its capacity.

[0123] In solid-state batteries, interfacial contact and interfacial stability issues are one of the pain points that limit their performance. Poor interfacial contact affects the battery's discharge capacity and also deteriorates the battery's rate performance and cycle performance. Due to the "solid-solid contact" characteristics of solid-state batteries, the contact between particles within the electrode layer includes a large number of point contacts, which cannot completely wet the electrode active material like the electrolyte in liquid batteries. This results in insufficient interfacial ion transport within the electrode layer, which in turn leads to suboptimal performance of the solid-state battery.

[0124] By doping the electrode layer with solid electrolyte materials, the ion conductivity of the electrode layer can be enhanced in theory, the charge transfer efficiency between the electrode active material and the outside world can be promoted, the charge capacity can be fully released, and the impedance can be reduced. Among the various solid electrolyte materials, sulfide solid electrolytes have a high ionic conductivity (about 10 -3 ~10 -2 S / cm, almost the same as commercial liquid electrolytes) and excellent mechanical properties, such as good flexibility, which give it excellent ion conductivity and good deformation ability. It is a solid electrolyte material with the most practical and industrial prospects.

[0125] However, in sulfide solid-state batteries with sulfide solid electrolytes doped in the negative electrode layer, interface stability remains a limiting factor. For example, the interface impedance between the sulfide solid electrolyte and the negative electrode material is large, and lithium dendrites are easily generated, causing battery short circuits. Therefore, building a stable interface between the sulfide solid-state battery and the negative electrode is one of the key factors in achieving high-performance sulfide solid-state batteries.

[0126] The activity of negative electrode active materials plays a significant role in improving the energy density of solid-state batteries. Silicon is an extremely outstanding negative electrode active material. However, silicon negative electrodes also face the following challenges: low electronic conductivity, which is not conducive to the construction of electron paths during battery charge and discharge; low lithium ion diffusion coefficient, which is not conducive to the effective transport of lithium ions during battery charge and discharge; and significant volume expansion during lithium insertion. These issues can lead to poor battery capacity and rapid cycle decay.

[0127] Based on this, according to various embodiments and examples of the present application, the embodiments and examples of the present application provide at least a silicon-containing negative electrode material, a method for preparing a coated silicon-based material, a negative electrode film, a solid-state battery, and an electrical device. The silicon-containing negative electrode material includes a coated silicon-based material, and a solid-state battery prepared using the silicon-containing negative electrode material has excellent comprehensive performance in terms of discharge capacity, rate performance, and cycle performance.

[0128] In this application, unless otherwise specified, the sulfide solid electrolyte located in the "electrolyte coating layer" is referred to as the "coated sulfide solid electrolyte" or the "first sulfide solid electrolyte", and the "blended sulfide solid electrolyte" that may be present in the silicon-containing negative electrode material is referred to as the "second sulfide solid electrolyte".

[0129] In this application, unless otherwise specified, "coated sulfide solid electrolyte" and "first sulfide solid electrolyte" have the same meaning and are used interchangeably. Unless otherwise specified, "blended sulfide solid electrolyte" and "second sulfide solid electrolyte" have the same meaning and are used interchangeably.

[0130] In a first aspect of the present application, a silicon-containing negative electrode material is provided, which includes a coated silicon-based material, wherein the coated silicon-based material includes a silicon base body and an electrolyte coating layer coated on at least a portion of the surface of the silicon base body; the electrolyte coating layer contains a sulfide solid electrolyte (which can be recorded as a first sulfide solid electrolyte or a coated sulfide solid electrolyte).

[0131] Without limitation, the first sulfide solid electrolyte in the electrolyte coating layer can be any suitable sulfide solid electrolyte in the art, as long as it can promote active ion conduction and alleviate the adverse effects of volume expansion of silicon-based materials on interfacial contact, and can improve the discharge capacity, rate performance and cycle stability of the solid-state battery.

[0132] In some embodiments, the "first sulfide solid electrolyte" has a certain ionic conductivity and a certain modulus, which can better promote active ion conduction and enhance the interface contact stability of the negative electrode layer, and can better improve the discharge capacity, rate performance and cycle stability of the solid-state battery.

[0133] Without limitation, in the coated silicon-based material, under the test condition of 20°C, the ionic conductivity of the first sulfide solid electrolyte may be greater than or equal to 0.1 mS / cm, optionally, greater than or equal to 0.5 mS / cm, further optionally, greater than or equal to 1 mS / cm, and may also be any of the following values, or greater than or equal to any of the following values, or an interval consisting of any two of the following values: 0.1 mS / cm, 0.2 mS / cm, 0.4 mS / cm, 0.5 mS / cm, 0.6 mS / cm, 0.7 mS / cm, 0.8 mS / cm, 0.9 mS / cm, 1 mS / cm, 1.2 mS / cm, 1.5 mS / cm, 1.6 mS / cm, 1.8 mS / cm, 2.0 mS / cm, 2.4 mS / cm, 2.5 mS / cm, etc.

[0134] In a non-limiting manner, under the test condition of 30°C, the ratio of the Young's modulus of the first sulfide solid electrolyte to the Young's modulus of the silicon matrix (RE ) is less than 1, optionally, less than or equal to 0.8, and can also be any of the following values, less than or equal to any of the following values, or an interval consisting of any two of the following values: 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc. The ratio of the Young's modulus of the sulfide solid electrolyte to the silicon matrix (R E ) can be selected from any of the following ranges: R E <1, R E ≤0.95, R E ≤0.8、0.6≤R E ≤0.95、0.6≤R E ≤0.8, etc.

[0135] In some embodiments, under the test condition of 20°C, the ionic conductivity of the first sulfide solid electrolyte is 1.82 SiP 0.036 The ratio of the ionic conductivity of S3 is greater than or equal to 1.

[0136] In some embodiments, under the test condition of 30°C, the Young's modulus of the first sulfide solid electrolyte is 1.82 SiP 0.036 The ratio of the Young's modulus of S3 is less than or equal to 1.

[0137] In this application, unless otherwise specified, a "silicon-containing anode material" is a material that can be used to prepare an anode active material layer. It is understood that because the electrolyte coating layer contains a sulfide solid electrolyte, a solid-state battery whose anode layer includes the silicon-containing anode material is a sulfide solid-state battery.

[0138] In this application, unless otherwise specified, a "coated silicon-based material" is a solid material. A "coated silicon-based material" is a material including "coated silicon-based particles".

[0139] The structure of the coated silicon-based particles in the silicon-containing negative electrode material provided in one embodiment of the present application can be referred to Figure 1 The coated silicon-based particle 60 includes a silicon base body 62 and an electrolyte coating layer 64 located on the surface of the silicon base body 62 .

[0140] The structure of the coated silicon-based particles in the silicon-containing negative electrode material provided in one embodiment of the present application can be referred to Figure 2 The coated silicon-based particle 60 includes a silicon base body 62 and an electrolyte coating layer 64 located on the surface of the silicon base body 62. The electrolyte coating layer 64 contains a sulfide solid electrolyte (referred to as a first sulfide solid electrolyte or a coated sulfide solid electrolyte 642).

[0141] Unless otherwise specified, a "sulfide solid-state battery" refers to a solid-state battery in which the electrolyte involved in the battery includes a sulfide solid electrolyte. For example, the sulfide solid electrolyte may be located in at least one of the positive electrode layer, solid electrolyte layer, and negative electrode layer of the sulfide solid-state battery. In the sulfide solid-state batteries involved in the embodiments or examples of this application, the sulfide solid electrolyte is located at least in the negative electrode layer of the sulfide solid-state battery. The sulfide solid-state battery may further be an all-solid-state battery.

[0142] In this application, unless otherwise specified, "all-solid-state battery" refers to a solid-state battery in which the electrolytes in the battery are all solid electrolytes. In this case, the positive electrode layer, the negative electrode layer and the electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery, so it can be called an "all-solid-state battery".

[0143] In this application, unless otherwise specified, the "solid-state battery" in any embodiment or example may be, but is not limited to, a sulfide all-solid-state battery. Unless otherwise specified, a "sulfide all-solid-state battery" refers to an all-solid-state battery in which the electrolyte involved in the battery includes a sulfide solid electrolyte.

[0144] In this application, unless otherwise specified, "sulfide electrolyte," "sulfide electrolyte component," "sulfide solid electrolyte," and "sulfide solid electrolyte component" have the same meaning and can be used interchangeably, referring to a solid electrolyte component in the form of a sulfide. The sulfide electrolyte includes sulfur (S) in the form of a sulfide. The "sulfide electrolyte" involved in the embodiments or examples of this application is not particularly limited in its form and can be an independent sulfide electrolyte substance or a part of a composite material, such as a sulfide electrolyte component in an electrolyte coating layer, a blended sulfide solid electrolyte, or a sulfide solid electrolyte in a solid electrolyte layer.

[0145] In this application, unless otherwise specified, the types of sulfide electrolyte components contained in different locations or different materials of a "sulfide solid-state battery" can be the same or different. For example, the types of coated sulfide solid electrolyte and blended sulfide solid electrolyte can also be the same or different.

[0146] In the coated silicon-based material containing silicon negative electrode material, a sulfide solid electrolyte with high ionic conductivity (which can be recorded as the first sulfide solid electrolyte) is used to coat the silicon base body, and an electrolyte coating layer is set on the surface of the silicon base body. When it is used to prepare a solid-state battery, it is beneficial to the conduction of active ions between the particles of the silicon-based material, reducing impedance, and helping to give full play to the capacity of the silicon-containing negative electrode material, which can improve the rate performance and cycle performance of the solid-state battery. In addition, the material of the aforementioned electrolyte coating layer is softer than that of the silicon base body, which is beneficial to alleviate the adverse effects of the volume expansion of the silicon-based material on the interface contact, improve the stability of ion transmission in the negative electrode layer, and help improve the cycle stability of the battery.

[0147] In the present application, unless otherwise specified, the "Young's modulus of the first sulfide solid electrolyte" may be the Young's modulus measured by the AFM method in shear mode. Those skilled in the art may obtain the test results in combination with conventional technical means in this field. The modulus of the first sulfide solid electrolyte may be obtained by testing with an atomic force microscope (AFM, such as Dimension icon / Dimension iconXR) equipped with a QNM module. The powder sample may be dispersed on a silicon wafer using a solvent (such as NMP) and dried for testing. The shear modulus under different pressures may be measured, and the average Young's modulus may be obtained by fitting the pressure and shear modulus data, and the resulting value may be used as the "Young's modulus" test value in this application.

[0148] In this application, unless otherwise specified, the ionic conductivity of the first sulfide solid electrolyte can be measured by electrochemical impedance spectroscopy (EIS). The test can be performed as follows: 120 mg of solid electrolyte powder is poured into a 10 mm diameter tablet mold, and the electrolyte powder is pressed into a dense disc at 360 MPa. Then, a 10 mm diameter cylindrical stainless steel current collector is used to clamp the solid electrolyte membrane in the mold at 120 MPa. The current collector is then connected to an electrochemical workstation and tested at a bias voltage of 10 mV and a frequency range of 10 6 Electrochemical impedance spectroscopy (EIS) is performed on solid electrolyte membranes in the range of Hz to 10Hz. The intersection of the curve from the high frequency band to the low frequency band in the electrochemical impedance spectrum and the Z' axis is recorded as the resistance value R. The ionic conductivity can be calculated using formula (1):

[0149]

[0150] Where d is the thickness of the solid electrolyte membrane, and A is the contact area between the solid electrolyte membrane and the current collector.

[0151] In some embodiments, the first sulfide solid electrolyte comprises a Li2S-SiS2-P2S5 ternary sulfide electrolyte.

[0152] In this application, unless otherwise specified, "Li2S-SiS2-P2S5 ternary sulfide electrolyte" refers to a sulfide electrolyte containing three sulfide forms Li2S, SiS2 and P2S5. These three sulfide forms Li2S, SiS2 and P2S5 can be combined in any suitable molar ratio as long as they can achieve the function of the aforementioned first sulfide solid electrolyte.

[0153] Among them, in the Li2S-SiS2-P2S5 ternary sulfide electrolyte, the atomic molar ratio of Li element to Si element is recorded as R Li / Si The atomic molar ratio of P element to Si element is denoted as R P / Si , without limitation, 1.80 <R Li / Si <1.84, 10.34 <R P / Si <0.38.

[0154] In some embodiments, the Li2S-SiS2-P2S5 ternary sulfide electrolyte includes Li 1.82 SiP 0.036 S3 can be further 1.82 SiP 0.036 S3.

[0155] Li2S-SiS2-P2S5 ternary sulfide electrolyte (such as Li 1.82 SiP 0.036 S3) has extremely excellent ionic conductivity, which can better improve the rate performance of the battery.

[0156] Without limitation, the silicon matrix may include one or more of elemental silicon, a silicon-carbon composite, a silicon oxide, and a silicon-carbon composite. In some embodiments, the silicon matrix includes a silicon-carbon composite, and further, the silicon-carbon composite may include a porous carbon matrix and nano-silicon located in the pores of the porous carbon matrix.

[0157] Silicon-based materials can be flexibly selected. Among them, silicon-carbon composites have the following advantages: nano-silicon is located in a porous carbon matrix, which can more effectively inhibit the expansion of silicon and is more conducive to improving the cycle life of the battery.

[0158] In some embodiments, in the coated silicon-based material, the weight ratio of the first sulfide solid electrolyte to the silicon matrix can be expressed as 1:m, which can be 1:(20-70), or optionally 1:(45-55). Without limitation, m can be any of the following values ​​or a range consisting of any two of the following values: 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, etc.

[0159] In some embodiments, the weight proportion of the first sulfide solid electrolyte in the coated silicon-based material can be 1wt% to 5wt%, optionally 1.5wt% to 02.5wt%, or any of the following percentages or an interval consisting of any two of the following percentages: 1wt%, 1.2wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.8wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, etc.

[0160] In some embodiments, the thickness of the electrolyte coating layer is 1 nm to 100 nm, optionally 10 nm to 50 nm, and can also be any of the following values ​​or an interval consisting of any two of the following values: 1 nm, 2 nm, 4 nm, 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 40 nm, 50 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 100 nm, etc.

[0161] In some embodiments, the coated silicon-based material satisfies one or more of the following characteristics (any numerical parameter in the following characteristics may also be selected from any appropriate numerical value or range in the context):

[0162] In the coated silicon-based material, the weight ratio of the first sulfide solid electrolyte to the silicon base body may be, but is not limited to, 1:(20-70), and may be optionally 1:(45-55);

[0163] The weight proportion of the first sulfide solid electrolyte in the coated silicon-based material is 0.01wt% to 0.05wt%, and can be optionally 0.017wt% to 0.021wt%;

[0164] The thickness of the electrolyte coating layer is 1 nm to 100 nm, and can be optionally 10 nm to 50 nm.

[0165] The amount of sulfide solid electrolyte coating can be adjusted by controlling one or more of the following parameters: the weight ratio of the sulfide solid electrolyte to the silicon matrix, the weight proportion of the sulfide solid electrolyte in the coated silicon-based material, and the thickness of the electrolyte coating layer. By controlling one or more of these parameters within the aforementioned ranges, it is possible to fully utilize the effects of improving the battery's discharge capacity, rate capability, and cycle performance, while also achieving high energy density.

[0166] In some embodiments, the D of the silicon matrix v50 or the particle size is less than or equal to 50μm, and can be selected from 1μm to 50μm, further selected from 1μm to 8μm, and further selected from 4μm to 6μm. It can also be any of the following values ​​or an interval consisting of any two of the following values: 1μm, 2μm, 4μm, 5μm, 6μm, 8μm, 10μm, 12μm, 15μm, 16μm, 18μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, etc.

[0167] In the context of this application, the volume cumulative distribution particle size D can be used v N (where N represents any value selected from 0 to 100) is used to characterize the particle size of the material, which refers to the particle size corresponding to when the cumulative volume distribution percentage of the material reaches N%. The particle size is less than or equal to D v The volume percentage of N is N%. v N can be obtained from the volume cumulative distribution curve of the material particle size. If there is no other explanation, the volume cumulative distribution curve starts from zero from the small particle size side. v 50 is used as an example. In this application, if there is no other description, D v 50 refers to the particle size corresponding to when the cumulative volume distribution percentage of the material reaches 50%. This parameter indicates that the particle size of 50% of the material volume is less than or equal to D v 50, and 50% of the volume of the material has a particle size larger than D v 50. Those skilled in the art will understand that v 50, and can be measured using instruments and methods known in the art. For example, it can be conveniently measured using a laser particle size analyzer, such as the Mastersizer 2000E Laser Particle Size Analyzer or the LS-909 Laser Particle Size Analyzer (Omega), manufactured by Malvern Instruments Ltd., UK, in accordance with GB / T 19077-2016 Particle Size Distribution by Laser Diffraction Method. Furthermore, for equipment such as the Malvern 2000 Laser Particle Size Analyzer, testing can be performed according to the standard procedures GB / T 19077-2016 / ISO 13320:2009.

[0168] In this application, unless otherwise specified, the particle size of a particle refers to the maximum diameter of the particle in each direction. Non-limiting examples of the particles referred to in this application include negative electrode active particles, coated silicon-based particles, negative electrode electrolyte particles, etc.

[0169] In this application, particle size analysis methods such as transmission electron microscopy (TEM) and laser particle size analyzers can be used to test and analyze the particle size of particles such as negative electrode electrolyte particles, negative electrode active particles, and coated silicon-based particles. These testing methods can also be used to test and analyze the particle size of other particles involved in this application (such as the raw materials used to provide the particle bodies, etc.), such as parameters such as particle size and particle size distribution, and the average values ​​of certain size parameters.

[0170] By converting the silicon base body into v 50 or the particle size is controlled within the aforementioned range, which is more conducive to the uniformity of the coating, thereby better improving the discharge capacity, rate performance and cycle performance of the battery.

[0171] In some embodiments, the electrolyte coating layer includes dot-shaped particles of a sulfide solid electrolyte.

[0172] In some embodiments, the particle size of the point-like particles of the sulfide solid electrolyte is less than or equal to 1 μm, and can be selected from 0.1 μm to 1 μm, or can be any of the following values ​​or an interval consisting of any two of the following values: 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, etc.

[0173] When the sulfide solid electrolyte exists in the form of point-like particles on the surface of the silicon base body, it is more conducive to improving the ionic conductivity and also to improving the coating stability of the coating layer when the silicon-based material undergoes volume expansion, thereby helping to more stably optimize the electrochemical performance of the battery.

[0174] By controlling the particle size of the dot-like particles within the aforementioned range, the contact area between the electrolyte material and the silicon-based material can be adjusted, thereby further improving the transport capacity of active ions.

[0175] In some embodiments, in at least a portion of the coated silicon-based material, the sulfide solid electrolyte is distributed discontinuously on the surface of the silicon-based body.

[0176] When the sulfide solid electrolyte is distributed in a discontinuous manner on the surface of the silicon base body, it is more conducive to improving the coating stability when the silicon-based material undergoes volume expansion.

[0177] In some embodiments, the weight proportion of the coated silicon-based material in the silicon-containing negative electrode material is greater than or equal to 50wt%, which can be selected from 50wt% to 99wt%, further selected from 75wt% to 97wt%, and further selected from 85wt% to 97wt%. It can also be any of the following percentages or an interval consisting of any two of the following percentages: 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, 90wt%, 95wt%, 96wt%, 97wt%, 99wt%, etc.

[0178] By controlling the weight proportion of the coated silicon-based material in the silicon-containing negative electrode material within the aforementioned range, it is beneficial to better play the comprehensive role of promoting the conduction of active ions and improving the stability of the interface contact. On the one hand, it can promote the conduction of active ions between the particles of the silicon-based material, fully exert the capacity of the silicon-containing negative electrode material, and improve the rate performance and cycle performance of the solid-state battery. On the other hand, it can also effectively inhibit the adverse effects of the volume expansion of the silicon-based material on the interface contact, thereby improving the cycle stability of the battery.

[0179] In some embodiments, the silicon-containing negative electrode material may or may not include a blended solid electrolyte. The blended solid electrolyte is a negative electrode electrolyte particle.

[0180] In this application, unless otherwise specified, "blended solid electrolyte" refers to the "coated sulfide solid electrolyte." The blended solid electrolyte and the negative electrode active particles are separate and distinct particles, and the blended solid electrolyte coexists with the negative electrode active particles in the silicon-containing negative electrode material in a physically blended manner. The "coated sulfide solid electrolyte (first sulfide solid electrolyte)" constitutes the same coated silicon-based particle together with the silicon base, and the coated sulfide solid electrolyte coexists with the silicon base in the silicon-containing negative electrode material in a coated form.

[0181] In some embodiments, the blended solid electrolyte includes a blended sulfide solid electrolyte.

[0182] Without limitation, the blended solid electrolyte may include thio-LISICON, Li6PS5Cl, Li 10 SnP2S 12, one or more of Li2S-P2S5 binary sulfur-based electrolyte, Li2S-SiS2 binary sulfur-based electrolyte, and Li2S-B2S3 binary sulfur-based electrolyte. "Li2S-P2S5 binary sulfur-based electrolyte" is a sulfide electrolyte containing two sulfurized forms, Li2S and P2S5. "Li2S-SiS2 binary sulfur-based electrolyte" is a sulfide electrolyte containing two sulfurized forms, Li2S and SiS2. "Li2S-B2S3 binary sulfur-based electrolyte" is a sulfide electrolyte containing two sulfurized forms, Li2S and B2S3. In the aforementioned Li2S-P2S5 binary sulfur-based electrolyte, Li2S-SiS2 binary sulfur-based electrolyte, and Li2S-B2S3 binary sulfur-based electrolyte, the molar ratio of the two sulfurized parts in the binary sulfur-based electrolyte can be any suitable combination and is not limited to 1:1.

[0183] In some embodiments, the weight proportion of the blended solid electrolyte in the silicon-containing negative electrode material can be but is not limited to 0wt% to 30wt%, and can be optionally 0.5wt% to 5wt%, or can be any of the following percentages or an interval consisting of any two of the following percentages: 0wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 5wt%, 6wt%, 8wt%, 10wt%, 12wt%, 15wt%, 16wt%, 18wt%, 20wt%, 25wt%, 30wt%, etc.

[0184] Introducing a blended solid electrolyte into a silicon-containing anode material can improve the overall ionic conductivity of the solid-state battery's anode layer. By controlling the weight ratio of the blended solid electrolyte in the silicon-containing anode material within the aforementioned range, this can improve the overall ionic conductivity of the solid-state battery's anode layer while also achieving a higher energy density.

[0185] In some embodiments, the silicon-containing negative electrode material satisfies one or more of the following characteristics:

[0186] The silicon-containing negative electrode material may or may not include a conductive agent (which may be recorded as a negative electrode conductive agent); optionally, the weight proportion of the negative electrode conductive agent in the silicon-containing negative electrode material may be, but is not limited to, 0wt% to 10wt%, optionally 0.1wt% to 10wt%, further optionally 0.1wt% to 2wt%, or any of the following percentages or an interval selected from any two of the following percentages: 0wt%, 0.1wt%, 0.2wt%, 0.4wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 5wt%, 6wt%, 8wt%, 10wt%, etc.;

[0187] The silicon-containing negative electrode material includes a binder (which can be referred to as a negative electrode binder); optionally, the weight proportion of the negative electrode binder in the silicon-containing negative electrode material can be but is not limited to 0.1wt% to 20wt%, and can further be 1wt% to 10wt%, and can also be any of the following percentages or an interval consisting of any two of the following percentages: 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 5wt%, 6wt%, 8wt%, 10wt%, 12wt%, 15wt%, 16wt%, 18wt%, 20wt%, etc.

[0188] By controlling the weight ratio of the negative electrode conductive agent in the silicon-containing negative electrode material, the overall electronic conduction and electrical contact in the negative electrode layer can be optimized, thereby improving the discharge capacity, rate performance and cycle performance of the battery.

[0189] By controlling the weight ratio of the negative electrode binder in the silicon-containing negative electrode material, the electrical contact between the active particles in the negative electrode layer can be optimized, the capacity of the negative electrode can be promoted, and the rate performance and cycle performance of the battery can be improved.

[0190] In the second aspect of the present application, a method for preparing a coated silicon-based material is provided, which can be used to prepare the coated silicon-based material described in the first aspect of the present application. The method can also be used to prepare coated silicon-based particles.

[0191] In some embodiments, a method for preparing a coated silicon-based material is provided, comprising the following steps:

[0192] The sulfide solid electrolyte is physically mixed with a silicon base body, and then sintered to form an electrolyte coating layer containing the sulfide solid electrolyte on at least a portion of the surface of the silicon base body to obtain a coated silicon-based material.

[0193] In some embodiments of yet another aspect of the present application, a method for preparing coated silicon-based particles is provided, comprising the following steps:

[0194] The sulfide solid electrolyte is physically mixed with a silicon base body, and then sintered to form an electrolyte coating layer containing the sulfide solid electrolyte on at least a portion of the surface of the silicon base body to prepare coated silicon-based particles.

[0195] In some other embodiments, the sulfide solid electrolyte is the first sulfide solid electrolyte defined in the first aspect of the present application.

[0196] In some embodiments, the method for preparing the coated silicon-based material satisfies any one or any appropriate multiple of the following characteristics:

[0197] The sulfide solid electrolyte is in granular form.v 50 or particle size is less than or equal to 1 μm, which can be 0.1 μm to 1 μm, or any of the following values ​​or an interval consisting of any two of the following values: 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, etc.;

[0198] The silicon base body is granular, and the D v 50 is less than or equal to 50 μm, and can be 1 μm to 50 μm, further 1 μm to 8 μm, and further 4 μm to 6 μm. It can also be any of the following values ​​or an interval consisting of any two of the following values: 1 μm, 2 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 12 μm, 15 μm, 16 μm, 18 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc.;

[0199] In the step of physically blending the sulfide solid electrolyte with the silicon matrix, the weight ratio of the sulfide solid electrolyte to the silicon matrix is ​​recorded as 1:m, and the weight ratio can be 1:(20-70), optionally 1:(45-55), and further optionally, m can be any of the following values ​​or an interval consisting of any two of the following values: 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, etc.;

[0200] The method for physical blending is dry blending;

[0201] The sintering atmosphere for sintering is argon;

[0202] The sintering temperature is 550°C to 650°C, and can be 580°C to 620°C.

[0203] The sintering time is 6 hours to 10 hours.

[0204] In some embodiments, the sulfide solid electrolyte is prepared by a method comprising the following steps:

[0205] The precursor raw materials of the sulfide solid electrolyte are mixed, ball-milled, and sintered in a sealed state to prepare the sulfide solid electrolyte.

[0206] In some embodiments, the method for preparing the coated silicon-based material satisfies any one or any appropriate multiple of the following characteristics:

[0207] The ball milling method is dry ball milling;

[0208] The ball milling beads used for ball milling include zirconium oxide ball milling beads;

[0209] The rotation speed of ball milling is 300r / min~400r / min, and can be selected as 300r / min~350r / min;

[0210] The ball milling time is 36h to 48h.

[0211] In some embodiments, the coated silicon-based material is the coated silicon-based material in the silicon-containing negative electrode material described in the first aspect of the present application.

[0212] In a third aspect of the present application, a negative electrode film is provided, which includes a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector, and the negative electrode active material layer includes the silicon-containing negative electrode material described in the first aspect of the present application.

[0213] In some embodiments, the negative electrode film is an all-solid-state negative electrode film.

[0214] In this application, unless otherwise specified, "all-solid-state anode film" refers to an anode film whose constituent materials are all solid.

[0215] In some embodiments, a negative electrode film is provided, which includes a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector, and the negative electrode active material layer includes the silicon-containing negative electrode material described in the first aspect of the present application.

[0216] In some embodiments, a negative electrode film is provided, comprising a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector, wherein the negative electrode active material layer comprises the coated silicon-based material described above and below.

[0217] Without limitation, the negative electrode film can be a standalone negative electrode film sheet or negative electrode sheet, which can be used to assemble a solid-state battery. The negative electrode film can also be a negative electrode film layer present in a multi-layer composite structure. For example, the constituent materials of the negative electrode film layer can be pressed into a film on the surface of a solid electrolyte layer. As a non-limiting example, the negative electrode film can be a negative electrode layer or a portion of a negative electrode layer of a solid-state battery.

[0218] In yet another aspect of the present application, a negative electrode active material layer is provided, which is the negative electrode active material layer described in any embodiment of the present application.

[0219] As defined above, the negative electrode active material layer includes at least negative electrode active particles, which contain negative electrode active materials. It is understood that the negative electrode active particles include the aforementioned coated silicon-based materials.

[0220] Without limitation, the weight percentage of the negative electrode active particles in the negative electrode active material layer may be greater than or equal to 50 wt %, and may be 50 wt % to 99 wt %, further 75 wt % to 97 wt %, and even further 85 wt % to 97 wt %. The weight percentage of the negative electrode active particles in the negative electrode active material layer may also be any of the following weight percentages or a range consisting of any two of the following weight percentages: 50 wt %, 55 wt %, 60 wt %, 65 wt %, 70 wt %, 75 wt %, 80 wt %, 85 wt %, 90 wt %, 95 wt %, 96 wt %, 97 wt %, 99 wt %, etc.

[0221] In some embodiments, the negative electrode active material layer may include negative electrode electrolyte particles. In a non-limiting manner, the weight proportion of the negative electrode electrolyte particles in the negative electrode active material layer may be 0 wt% to 30 wt%, optionally 0.5 wt% to 5 wt%, or any of the following percentages or an interval selected from any two of the following percentages: 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 16 wt%, 18 wt%, 20 wt%, 25 wt%, 30 wt%, etc.

[0222] In some embodiments, the negative electrode active material layer includes negative electrode active particles and negative electrode electrolyte particles, wherein the negative electrode active particles include coated silicon-based materials.

[0223] The following are some additional descriptions about the negative electrode film.

[0224] In this application, unless otherwise specified, "anode film" refers to a film that can be used as anode for solid-state batteries, including at least a cathode active material layer and usually an anode current collector. The anode film includes the silicon-containing anode material described in the first aspect of this application.

[0225] In some embodiments, the negative electrode film includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector. The definition of the negative electrode active material layer can be found in the above text.

[0226] In some embodiments, see Figure 3 The negative electrode film 30 includes a negative electrode current collector 310 and a negative electrode active material layer 320 located on one side of the negative electrode current collector 310 .

[0227] In some embodiments, see Figure 4 The negative electrode film 30 includes a negative electrode current collector 310 and negative electrode active material layers 320 located on both sides of the negative electrode current collector 310 .

[0228] In this application, unless otherwise specified, the negative electrode active material layer sample can be obtained from the solid-state battery in the following manner: the battery can be disassembled to obtain the active material layer sample of the electrode plate, and the active material layer can be further analyzed by the following method: the nano-spatial dynamic resolution and layer-by-layer cutting technology of FIB-SEM are used to reconstruct the three-dimensional structure of the sample, and the distribution and proportion of each element are obtained by combining EDS element energy spectrum analysis, and finally the composition and thickness and other parameters of each structural layer of the active material layer are obtained through software quantitative analysis.

[0229] In this application, unless otherwise specified, the types and contents of components such as negative electrode active particles (including coated silicon-based particles) and negative electrode electrolyte particles in the negative electrode active material layer of the solid-state battery can be detected by the following method: the structure and composition analysis of the negative electrode active material layer can be tested and analyzed by focused electron beam (FIB) technology, scanning electron microscope (SEM) and elemental analysis technology, for example, it can be obtained by combining cryo-focused electron beam (FIB) continuous sectioning, cross-section SEM morphology observation, energy dispersive spectroscopy (EDS) element spectrum and three-dimensional reconstruction analysis software analysis. For example, a cryo-focused ion beam (FIB) is used to finely slice the sample layer by layer in the transverse direction at different thickness positions (the minimum scale can reach nanometer-level thin slices), and separate different layers of samples at different thickness positions. It can also be tested by scanning electron microscope (SEM), and the morphology, structure and element distribution of each layer of the cross section are analyzed under FIB continuous sectioning. Combined with three-dimensional structure reconstruction software, the three-dimensional structure of the sample can be reconstructed, and the mass and / or volume of different areas of the sample to be tested can be estimated. As a non-limiting example, the above parameters may be tested and analyzed using a FEI Scios 2HiVac device.

[0230] In the present application, unless otherwise specified, the particle size and particle size distribution of each solid particle in the negative electrode active material layer sample of the solid-state battery can be analyzed in the following manner, which may include analyzing the particle size and particle size distribution of particle components such as negative electrode active particles and negative electrode electrolyte particles: In the present application, unless otherwise specified, FIB-SEM combined with EDS testing can be used to obtain a two-dimensional image with different color markings for different components, and particle components such as negative electrode active particles and negative electrode electrolyte particles can be distinguished according to the type of components. The particle size and particle size distribution of particle components such as negative electrode active particles and negative electrode electrolyte particles can be analyzed using the software provided by the EDS instrument.

[0231] In another aspect of the present application, a negative electrode membrane is provided, which includes a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector, and the negative electrode active material layer is the silicon-containing negative electrode material described in the first aspect of the present application.

[0232] The negative electrode membrane can be directly used as a negative electrode plate to assemble a solid-state battery, but is not limited thereto.

[0233] In a fourth aspect of the present application, a solid-state battery is provided, which includes the negative electrode film described in the third aspect of the present application.

[0234] In some embodiments, a solid-state battery is provided, comprising a positive electrode layer, a solid electrolyte layer, and a negative electrode layer; the negative electrode layer comprises the negative electrode film described in the third aspect of the present application.

[0235] In any related embodiment of the aforementioned aspects, the solid-state battery may be a sulfide solid-state battery. The definition of sulfide solid-state battery can be found in the above text.

[0236] In any related embodiment of the aforementioned aspects, the solid-state battery may be a sulfide all-solid-state battery. The definition of a sulfide all-solid-state battery can be found in the above text.

[0237] In any relevant embodiment of the aforementioned aspects, the solid-state battery may be a lithium-ion solid-state battery, and further may be a lithium-ion all-solid-state battery.

[0238] In a fifth aspect of the present application, an electrical device is provided, which includes at least one of the negative electrode film described in the third aspect of the present application and the solid-state battery described in the fourth aspect of the present application.

[0239] In this application, the electrochemical performance of a battery, unless otherwise specified, generally includes comprehensive performance in terms of discharge capacity, rate capability and cycle performance.

[0240] 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.

[0241] In this application, unless otherwise specified, a "solid-state battery cell" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and its components are all solid. In some embodiments, the solid-state battery cell can be an all-solid-state battery cell.

[0242] Without limitation, a solid-state battery cell (which may be an all-solid-state battery cell) may include a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, wherein the solid electrolyte layer is located between the positive electrode layer and the negative electrode layer. During the charge and discharge process of the battery, active ions are embedded and extracted back and forth between the positive electrode layer and the negative electrode layer. The solid electrolyte layer acts as an ion conductor between the positive electrode layer and the negative electrode layer, and can also isolate the positive electrode layer from the negative electrode layer to prevent short circuits between the positive and negative electrodes.

[0243] Unless otherwise specified, the negative electrode layer in the solid-state battery includes the silicon-containing negative electrode material described in the first aspect of the present application.

[0244] Unless otherwise specified, the negative electrode layer in the solid-state battery includes the negative electrode film described in the third aspect of the present application. The negative electrode layer can be composed solely of the negative electrode film described in the third aspect of the present application, or the negative electrode film described in the third aspect of the present application can be combined with other films suitable for the negative electrode to form the negative electrode layer.

[0245] The following are some other descriptions about the positive electrode film.

[0246] The positive electrode layer can be provided by a positive electrode sheet or positive electrode membrane that can be used in solid-state batteries in the art. Alternatively, the constituent materials of the positive electrode layer can be directly pressed onto one surface of the solid electrolyte layer to form a positive electrode membrane layer. The positive electrode membrane can be combined with other films suitable for the positive electrode to form a positive electrode sheet or positive electrode layer.

[0247] The positive electrode layer can be prepared by a dry process or a wet process. For example, a dry process can be used to form a film by pressing. Another example is a wet process to form a film by coating.

[0248] In some embodiments, the positive electrode film includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The definition of the positive electrode active material layer can be found in the above text.

[0249] 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 base layer and a metal layer formed on at least one surface of the polymer material base layer. In the positive electrode current collector, the composite current collector may be obtained by forming a metal material on a polymer material substrate. In the positive electrode current collector, non-limiting examples of the metal material may include one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. In the positive electrode current collector, non-limiting examples of the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0250] Without limitation, in the positive electrode film or positive electrode layer, the thickness of the positive electrode active material layer is 30μm to 400μm, optionally 60μm to 130μm, and can also be any of the following thicknesses or an interval consisting of any two of the following thicknesses: 30μm, 40μm, 50μm, 60μm, 80μm, 100μm, 120μm, 130μm, 140μm, 150μm, 160μm, 180μm, 200μm, etc.

[0251] In this application, unless otherwise specified, the "thickness of the positive electrode active material layer" in the positive electrode film refers to the total thickness of the positive electrode film. When the positive electrode active material layer is provided on both sides of the positive electrode current collector, the thickness of the positive electrode active material layer refers to the sum of the thicknesses of both sides.

[0252] As a non-limiting example, the positive electrode current collector has two surfaces facing away from each other in its thickness direction, and the positive electrode active material layer is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0253] The positive electrode layer includes a positive electrode active material layer. The positive electrode active material layer includes positive electrode active particles. The positive electrode active particles contain a positive electrode active material.

[0254] Without limitation, the weight percentage of the positive electrode active particles or the positive electrode active substance in the positive electrode active material layer can be ≥80wt%, further can be ≥90wt%, and can also be any of the following weight percentages or an interval consisting of any two of the following weight percentages: 80wt%, 82wt%, 84wt%, 85wt%, 86wt%, 88wt%, 90wt%, 92wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, etc.

[0255] In some embodiments, the positive electrode active material layer includes positive electrode electrolyte particles. Without limitation, the weight proportion of the positive electrode electrolyte particles in the positive electrode active material layer can be 0.1wt% to 30wt%, optionally 5wt% to 20wt%, and the weight proportion of the positive electrode electrolyte particles in the positive electrode active material layer can also be any of the following weight percentages or a range selected from any two of the following weight percentages: 0.1wt%, 0.2wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.8wt%, 1wt%, 1 .2wt%, 1.5wt%, 1.6wt%, 1.8wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 12wt%, 14wt%, 15wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 25wt%, 26wt%, 28wt%, 30wt%, etc.

[0256] In some embodiments, the positive electrode active material layer includes positive electrode active particles and positive electrode electrolyte particles.

[0257] In some embodiments, the positive electrode active material in the positive electrode active particles includes an oxide positive electrode active material. Further, the positive electrode active material includes a lithium transition metal oxide.

[0258] Non-limitingly, the oxide positive electrode active material in the positive electrode active material (such as lithium transition metal oxide) may include lithium transition metal oxides that are well known in the art and can be used as positive electrode active materials in solid-state batteries, but are not limited thereto. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and modified compounds thereof. Non-limiting examples of lithium cobalt oxide may include LiCoO2; non-limiting examples of lithium nickel oxide may include LiNiO2; non-limiting examples of lithium manganese oxide may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxide may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ) etc. Non-limiting examples of lithium nickel cobalt aluminum oxide may include LiNi 0.80 Co 0.15 Al 0.05 O2.

[0259] Taking a solid-state battery in which active ions include lithium ions as an example, it is understandable that the solid-state battery will be accompanied by the deintercalation and consumption of lithium (Li) during the charge and discharge process, and the content of Li in the positive electrode layer (including the positive electrode film in the context) is different when the battery is discharged to different states. In the exemplary description of the positive electrode active material in this application, unless otherwise specified, the content of Li can be the initial state of the material or the non-initial state after the charge and discharge cycle. The positive electrode active material is applied to the positive electrode layer in the solid-state battery system. After the charge and discharge cycle, 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 using atomic molar content, but is not limited to this. 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 appropriate modification on the basis of the listed positive electrode active materials are also within the scope of positive electrode active materials. The aforementioned appropriate modification refers to an acceptable modification method for the positive electrode active material, and a non-limiting example is coating modification. In the exemplary descriptions of the positive electrode active material in this application, the oxygen (O) content is generally a theoretical value. Lattice oxygen release will cause the atomic molar content of oxygen to change, and the actual O content will fluctuate. The O content can be measured by atomic molar content, but is not limited to this.

[0260] In some embodiments, in addition to oxide positive electrode active materials (such as lithium transition metal oxides), the positive electrode active material may also include other positive electrode active materials that are well known in the art and can be used for solid-state batteries. As a non-limiting example, other positive electrode active materials that can be used for solid-state batteries may include one or more of the following materials: lithium-containing phosphates with an olivine structure and modified compounds thereof. However, the present application is not limited to these materials, and other existing materials that can be used as positive electrode active materials for solid-state batteries may also be used. These positive electrode active materials can be used alone or in combination of two or more. 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, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. An example of lithium iron phosphate is LiFePO4 (also referred to as LFP). An example of lithium manganese phosphate is LiMnPO4.

[0261] In some embodiments, the lithium transition metal oxide includes lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese-rich positive electrode active material (definition can be found below) and one or more modified forms of any of the foregoing positive electrode active materials; the modified form can include one or more of doping modification and coating modification.

[0262] In some embodiments, the positive electrode active material layer includes a conductive agent (which may be referred to as a positive electrode conductive agent). As a non-limiting example, the positive electrode conductive agent may be a carbon conductive agent. Non-limitingly, the carbon conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers. In some embodiments, the positive electrode conductive agent may include but is not limited to one or more of SP, KS-6, acetylene black, Ketjen black ECP with a branched structure, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs) and graphene. Non-limitingly, the weight percentage of the positive electrode conductive agent in the positive electrode active material layer may be 0 to 10 wt%, further 0 to 8 wt%, further 0 to 5 wt%, further 0.1 wt% to 3 wt%, based on the total weight of the positive electrode active material layer. The weight percentage of the positive electrode conductive agent in the positive electrode active material layer may also be 0.1 wt% to 5 wt%, 0.2 wt% to 5 wt%, 0.5 wt% to 5 wt%, 0.1 wt% to 3 wt%, etc.

[0263] In some embodiments, the positive electrode active material layer optionally includes a binder (which may be referred to as a positive electrode binder). As a non-limiting example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin. Typically, the weight percentage of the binder in the positive electrode active material layer may be 0 to 10 wt%, further 0 to 8 wt%, further 0.1 wt% to 5 wt%, further 1 wt% to 5 wt%, based on the total weight of the positive electrode active material layer.

[0264] Without limitation, the positive electrode active material layer may include positive electrode active particles, positive electrode electrolyte particles, a positive electrode conductive agent, and a binder. The type and content of each component can be found in the context of this application.

[0265] The positive electrode film can be prepared by a dry process or a wet process. For example, a dry process can be used to press the positive electrode film. Alternatively, a wet process can be used to apply the positive electrode film and then dry the positive electrode film.

[0266] In some embodiments, a positive electrode membrane (a positive electrode membrane can be used as a positive electrode sheet) can be prepared in the following manner: the components for preparing the positive electrode membrane, such as positive electrode active particles, positive electrode electrolyte particles, positive electrode conductive agent, optional positive electrode binder and any other components are dry-mixed, and then the mixed material is heated, pressurized and kneaded into a mass material, which is hot rolled to form a self-supporting positive electrode sheet, and the self-supporting positive electrode sheet is hot-rolled with the positive electrode collector. The self-supporting positive electrode sheet can be compounded on at least one side (one side or two sides) of the positive electrode collector to obtain a positive electrode membrane. Without limitation, a double planetary mixer can be used for dry mixing. Without limitation, an internal mixer can be used for heating, pressurizing and kneading. Without limitation, the temperature for hot rolling can be 75°C to 85°C, further such as 78°C, 80°C, 82°C, etc. The method of assembling solid-state batteries using positive electrode membranes can be suitable for industrial mass production. A similar method can be used to prepare negative electrode membranes or negative electrode sheets.

[0267] In some embodiments, a positive electrode membrane can be prepared by dispersing the components used to prepare the positive electrode membrane, such as the positive electrode active particles, positive electrode electrolyte particles, positive electrode conductive agent, binder, and any other components, in an organic solvent to form a positive electrode slurry. Furthermore, the positive electrode slurry is coated on at least one surface of a positive electrode current collector. After drying and cold pressing, the positive electrode membrane can be obtained. The cold pressing can be performed using a cold rolling mill. The organic solvent in the positive electrode slurry can include one or more of p-xylene, trimethylbenzene, butyl butyrate, heptane, and can further be p-xylene. The surface of the positive electrode current collector coated with the positive electrode slurry can be a single surface of the positive electrode current collector or both surfaces of the positive electrode current collector. The solid content of the positive electrode slurry can be 40 wt% to 80 wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000 mPa·s to 25000 mPa·s. When applying the positive electrode slurry, the coating unit area density (single side) based on dry weight (excluding solvent) can be 15 mg / cm 2 ~35mg / cm 2 The compaction density of the positive electrode membrane can be 3.0g / cm 3 ~3.6g / cm 3 , optional 3.3g / cm 3 ~3.5g / cm 3 .

[0268] The “compacted density” used in this application has a meaning well known in the art and is one of the reference indicators of material energy density. In this application, unless otherwise specified, the compacted density of an electrode layer refers to the ratio of the mass of the electrode active material layer to its volume. The compacted density of a positive electrode layer, a positive electrode sheet, a positive electrode film or a positive electrode membrane refers to the ratio of the mass of the positive electrode active material layer to its volume, and the compacted density of a negative electrode layer, a negative electrode sheet, a negative electrode film or a negative electrode membrane refers to the ratio of the mass of the negative electrode active material layer to its volume.

[0269] Compacted density = coating area density / thickness of electrode active material layer.

[0270] Coating area density = slurry dry weight / electrode active material layer area.

[0271] The double-sided thickness of the electrode active material layer corresponds to the sum of the coating surface density on both sides, and the single-sided thickness corresponds to the single-sided coating surface density; when the electrode active material layers on both sides of the current collector are basically the same, it can be calculated according to the following formula: compaction density = single-sided coating surface density / single-sided thickness of the electrode active material layer.

[0272] The “single-sided” and “double-sided” electrode active material layers refer to the positional distribution relative to the current collector.

[0273] The following is some description about the solid electrolyte layer.

[0274] The solid electrolyte layer plays the role of conducting ions between the positive electrode layer and the negative electrode layer, and can also isolate the positive electrode layer and the negative electrode layer to prevent the positive and negative electrodes from short-circuiting.

[0275] It is understood that the solid electrolyte layer includes a solid electrolyte. The solid electrolyte in the solid electrolyte layer can be a solid electrolyte known in the art that can be used in solid-state batteries.

[0276] The types of solid electrolytes present in different layers of a solid-state battery can be the same or different. For example, the solid electrolytes in the positive electrode electrolyte particles and the solid electrolyte layer can be the same or different.

[0277] As a non-limiting example, the positive electrode electrolyte particles and the solid electrolyte in the solid electrolyte layer can each independently include one or more of the following materials: one or more of a sulfide solid electrolyte, a halide solid electrolyte, an oxide solid electrolyte, a polymer solid electrolyte, etc. The type of sulfide solid electrolyte in the solid electrolyte layer can be the same as or different from the sulfide solid electrolyte in the positive electrode layer (such as the aforementioned positive electrode film). Taking a sulfide solid electrolyte as an example, a sulfide solid electrolyte refers to a solid electrolyte containing a sulfide electrolyte component, that is, a sulfide solid electrolyte is a sulfide electrolyte.

[0278] As another non-limiting example, the solid electrolyte in the positive electrode electrolyte particles and the solid electrolyte layer may each include but is not limited to one or more of an oxide solid electrolyte, a sulfide solid electrolyte and a halide solid electrolyte. In some embodiments, the solid electrolyte in the positive electrode electrolyte particles and the solid electrolyte layer may each include but is not limited to one or more of an Argyrodite-type sulfide electrolyte and a halide electrolyte. Among them, non-limiting examples of oxide solid electrolytes may include LISICON-type oxide electrolytes (such as γ-Li3PO4, etc.), NASICON-type oxide electrolytes (such as Li 1+x Al x Ge 2-x (PO4)3,Li 1+x Al x Ti 2-x (PO4)3, etc., 0≤x≤1), Garnet type (such as Li7La3Zr2O12, etc.), Perovskite type oxide electrolyte (such as Li 3x La 2 / 3-x TiO3, etc., 0≤x≤0.5) etc. Non-limiting examples of sulfide-based solid electrolytes may include Li 10 GeP2S 12 , Li2S-P2S5 binary sulfur electrolyte, Argyrodite type (such as Li6PS5Cl, Li 5.5 PS 5.5 Cl 1.5 Non-limiting examples of the halide-based solid electrolyte may include one or more of Li3InCl6, Li3YCl6, Li3ScCl6, Li3ErCl6, Li2ZrCl6, etc.

[0279] In some embodiments, the solid electrolyte layer may be pressed from a solid electrolyte material into a solid electrolyte membrane.

[0280] In some embodiments, the thickness of the solid electrolyte layer may be 0.1 μm to 1000 μm, and may be optionally 10 μm to 100 μm, 100 μm to 800 μm, 500 μm to 800 μm, or the like.

[0281] The following is some description about the negative electrode layer.

[0282] In this application, unless otherwise specified, "anode film" refers to a film that can be used as anode for solid-state batteries, including at least a cathode active material layer and usually an anode current collector. The anode film includes the silicon-containing anode material described in the first aspect of this application.

[0283] The negative electrode layer can be provided by a negative electrode sheet or negative electrode membrane that can be used in solid-state batteries in the art. Alternatively, the negative electrode layer component materials can be directly pressed onto one surface of the solid electrolyte layer to form a negative electrode membrane layer. The negative electrode membrane can be combined with other films suitable for the negative electrode to form a negative electrode sheet or negative electrode layer.

[0284] The negative electrode layer can be prepared by a dry process or a wet process. For example, a dry process can be used to form a film by pressing. Another example is a wet process can be used to form a film by coating.

[0285] The negative electrode layer includes a negative electrode active material layer. The negative electrode active material layer includes negative electrode active particles. The negative electrode active particles contain a negative electrode active material.

[0286] Without limitation, the weight percentage of the negative electrode active particles or the negative electrode active material in the negative electrode active material layer may be ≥80 wt %, and further may be ≥90 wt %.

[0287] In some embodiments, the negative electrode sheet or negative electrode film may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material. As a non-limiting example, the negative electrode current collector has two surfaces that face away from each other in the thickness direction of the negative electrode current collector, and the negative electrode active material layer is disposed on either or both of the two facing surfaces of the negative electrode current collector. In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. In the negative electrode current collector, the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. In the negative electrode current collector, the composite current collector may be formed by forming a metal material on a polymer material base layer. Non-limiting examples of the metal material in the negative electrode current collector may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. In the negative electrode current collector, non-limiting examples of the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), and the like.

[0288] In some embodiments, the negative electrode active material layer may optionally include a negative electrode conductive agent. Without limitation, 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. Without limitation, the weight percentage of the negative electrode conductive agent in the negative electrode active material layer may be 0 wt% to 10 wt%, optionally 0.1 wt% to 10 wt%, and further optionally 0.1 wt% to 2 wt%.

[0289] In some embodiments, the negative electrode active material layer optionally includes a negative electrode binder. As a non-limiting example, the negative electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin. Non-limitingly, the weight proportion of the negative electrode binder in the negative electrode active material layer may be 0-10wt%, further 0-5wt%, further 1wt%-5wt%, and further optionally 1wt%-3wt%.

[0290] In some embodiments, the negative electrode active material layer may optionally include other additives, such as a thickener (e.g., sodium carboxymethyl cellulose (CMC-Na)). The weight percentage of the other additives in the negative electrode active material layer may be 0-15 wt %, further preferably 0-10 wt %, further preferably 0-5 wt %, further preferably 0-3 wt %, and further preferably 0-2 wt %.

[0291] In some embodiments, the negative electrode membrane (the negative electrode membrane can be used as the negative electrode sheet) can be prepared in the following manner: the components for preparing the negative electrode membrane, such as the silicon-containing negative electrode material and any other components are dry-mixed, and then the mixed material is heated, pressurized and kneaded into a mass material, and hot roller pressed to form a self-supporting negative electrode sheet, and the self-supporting negative electrode sheet is hot-rolled and compounded with the negative electrode current collector. The self-supporting negative electrode sheet can be compounded on at least one side (one side or two sides) of the negative electrode current collector to obtain a negative electrode membrane. Without limitation, a double planetary mixer can be used for dry mixing. Without limitation, an internal mixer can be used for heating, pressurizing and kneading. The method of assembling solid-state batteries using negative electrode membranes can be suitable for industrial mass production. When the negative electrode material is prepared into a negative electrode active material layer by a dry method, a positive electrode conductive agent can be set in the negative electrode material to improve the electron conductivity of the negative electrode active material layer.

[0292] In some embodiments, the negative electrode sheet or negative electrode membrane can be prepared in the following manner: the components for preparing the negative electrode sheet or negative electrode membrane, such as the silicon-containing negative electrode material and any other components, are dispersed in a solvent (non-limiting examples of solvents include xylene, N-methylpyrrolidone (NMP), etc.) to form a negative electrode slurry. Further, the negative electrode slurry is coated on at least one side of the surface of the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet or negative electrode membrane can be obtained. The cold pressing can be performed using a cold rolling mill. The surface of the negative electrode collector coated with the negative electrode slurry can be a single surface of the negative electrode collector or on both surfaces of the negative electrode collector. The solid content of the negative electrode slurry can be 30wt% to 70wt%, optionally 40wt% to 60wt%. When coating the negative electrode slurry, the coating unit surface density based on dry weight (excluding solvent) can be 1.5mg / cm 2 ~18mg / cm 2 , but not limited thereto. The compaction density of the negative electrode sheet or negative electrode membrane can be 1.0 g / cm 3 ~2.0g / cm 3 , 1.0g / cm 3 ~1.8g / cm 3 When the negative electrode material is prepared into a negative electrode slurry by a wet method and then prepared into a negative electrode active material layer, a binder can be provided in the negative electrode slurry to assist film formation and also facilitate the formation of a good electrical contact network between active particles in the negative electrode active material layer.

[0293] In a non-limiting manner, the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet can be stacked in sequence, the solid electrolyte can be placed between the positive electrode membrane and the negative electrode membrane, and the solid-state battery cell can be prepared by hot rolling.

[0294] In a non-limiting manner, the positive electrode membrane, the solid electrolyte membrane and the negative electrode membrane may be stacked in sequence, the solid electrolyte may be placed between the positive electrode membrane and the negative electrode membrane, and the solid-state battery cell may be prepared by hot rolling.

[0295] In some embodiments, the solid-state battery cell 5 includes a solid-state battery cell 52 .

[0296] In some embodiments, the solid-state battery cell is an all-solid-state battery cell.

[0297] In some embodiments, the solid-state battery cell 52 (which may be an all-solid-state battery cell) includes a positive electrode layer 200, a solid electrolyte layer 100, and a negative electrode layer 300 stacked in sequence. An example of this can be found in Figure 5 Unless otherwise specified, the negative electrode layer 300 includes a negative electrode film 30 .

[0298] In some embodiments, the solid-state battery cell 52 includes a positive electrode layer 200, a solid electrolyte layer 100, and a negative electrode layer 300 stacked in sequence, wherein the negative electrode layer 300 includes a negative electrode film 30, the negative electrode film 30 includes a negative electrode current collector 310 and a negative electrode active material layer 320 located on both sides of the negative electrode current collector, and the negative electrode active material layer 320 is disposed between the negative electrode current collector 310 and the solid electrolyte layer 100. One example can be referred to Figure 6 .

[0299] In some embodiments, the solid-state battery may include an outer packaging that can be used to encapsulate the solid-state battery cell.

[0300] In some embodiments, the outer packaging of the solid-state battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the solid-state battery can also be a soft package, such as a bag-type soft package. The material of the soft package can be plastic. Further, non-limiting examples of plastic can include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0301] The present application has no particular restrictions on the shape of the solid-state battery cell, which can be cylindrical, square or any other shape. For example, Figure 7 The solid-state battery cell 5 is a square structure as an example.

[0302] In some embodiments, reference Figure 8 The outer packaging may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The solid-state battery cell 52 is encapsulated in the receiving cavity. The number of solid-state battery cells 52 contained in the solid-state battery cell 5 can be one or more, and those skilled in the art can select according to actual needs.

[0303] The solid-state battery can be a battery module 4 or a battery pack 1 .

[0304] The battery module includes at least one solid-state battery cell. The number of solid-state battery cells contained in the battery module can be one or more, and those skilled in the art can select an appropriate number based on the application and capacity of the battery module.

[0305] Figure 9 4 is an example of a battery module. Figure 9 In the battery module 4, the plurality of solid-state battery cells 5 may be arranged in sequence along the length of the battery module 4. Of course, they may also be arranged in any other manner. The plurality of solid-state battery cells 5 may further be fixed by fasteners.

[0306] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of solid-state battery cells 5 are received in the receiving space.

[0307] In some embodiments, the battery modules may be assembled into a battery pack. The battery pack may contain one or more battery modules. Those skilled in the art may select an appropriate number based on the application and capacity of the battery pack.

[0308] Figure 10 and Figure 11 The battery pack 1 is used as an example. Figure 10 and Figure 11 The battery pack 1 may include a battery box and multiple battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner in the battery box.

[0309] In some embodiments, the electrical device includes the solid-state battery of any embodiment provided herein.

[0310] Without limitation, solid-state batteries can be used as power sources for electrical devices or as energy storage units for electrical devices. Electrical devices may include, but are not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, and the like. Examples of mobile devices include, but are not limited to, mobile phones and laptops; examples of electric vehicles include, but are not limited to, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric motorcycles, and electric tools. The electrical device may also be used in fields such as military equipment and aerospace, and in energy storage power systems such as hydropower, thermal power, wind power, and solar power stations.

[0311] As an electrical device, a solid-state battery can be selected according to its usage requirements.

[0312] Figure 12 The example of an electric device 6 is shown. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the electric device's requirements for high power and high energy density of solid-state batteries, a battery pack or battery module can be used.

[0313] Another example device may be a mobile phone, a tablet computer, a laptop computer, etc. Such a device is usually required to be lightweight and thin, and may use a solid-state battery as a power source.

[0314] Below, some embodiments of the present application are described. The embodiment described below is exemplary, is only used to explain the present application, and cannot be construed as limiting the present application. In the embodiment, if no technology or conditions are indicated, it is carried out according to the description above, or according to the technology or conditions described in the document in this area, or according to the product specification. Reagents used or instruments that do not indicate manufacturers are conventional products that can be obtained commercially, or can be synthesized in a conventional manner by commercially available products.

[0315] Unless otherwise specified, in the following examples and comparative examples, raw materials with the same chemical formula are from the same synthesis batch or the same product number, or are prepared according to the same stoichiometric ratio and in accordance with the same method.

[0316] In the following examples, room temperature refers to 20°C to 30°C.

[0317] D v 50 tests:

[0318] In the following examples and comparative examples, the D values ​​of the positive electrode active particles, positive electrode electrolyte particles and oxygen storage particles are v 50 can be tested and confirmed by the following method: Equipment model: Malvern 2000 (MasterSizer 2000) laser particle size analyzer, reference standard process: GB / T19077-2016 / ISO 13320:2009, specific test process: take an appropriate amount of the sample to be tested (the sample concentration is guaranteed to be 8%-12% (w / v) shading), add 20mL of deionized water, and at the same time, ultraviolet for 5 minutes (53KHz / 120W) to ensure that the sample is completely dispersed, and then measure the sample according to GB / T19077-2016 / ISO 13320:2009 standard.

[0319] The transmission electron microscope (TEM) was FEI / Talos F200X, and the test acceleration voltage was 200 kV.

[0320] XRD test instrument and parameters: D8 Advance Da Vinci X, Cu Kα1, scanning range 20°~110°, scanning speed 5° / min.

[0321] In the following examples and comparative examples, unless otherwise specified, steps involving sulfide electrolyte materials were carried out in an argon atmosphere.

[0322] It should be noted that sulfide all-solid-state batteries are used as non-limiting examples of solid-state batteries in the following embodiments and examples.

[0323] Unless otherwise specified, the counting method for "approximate numbers" in micrometers (μm) or nanometers (nm) involved in the following examples is as follows: for values ​​accurate to one decimal place, the fluctuation range is within ±0.02; for values ​​accurate to the unit digit between 1 and 9, the fluctuation range is within ±0.2; for values ​​accurate to the unit digit between 10 and 99, the fluctuation range is within ±2.

[0324] 1. Preparation Example

[0325] The following examples use the following method to prepare sulfide all-solid-state batteries, including the following steps:

[0326] Step 1: In an argon-filled glove box, grind the positive electrode active particles, sulfide solid electrolyte, conductive agent and binder in a mortar to obtain a composite positive electrode powder.

[0327] Step 2: Press the sulfide electrolyte into a solid electrolyte membrane in a tableting mold to form a solid electrolyte layer in an all-solid-state battery.

[0328] Step 3: Spread the composite positive electrode powder on one side surface of the solid electrolyte membrane, press to form a composite membrane including a positive electrode layer and a solid electrolyte layer, and demould to obtain a positive electrode layer / electrolyte layer composite membrane.

[0329] Step 4: Assemble the positive electrode layer / electrolyte layer composite membrane prepared in step 3 into a pressure battery mold, assemble the silicon-containing negative electrode material on the other side of the solid electrolyte layer, and apply pressure to form the negative electrode layer. The obtained all-solid-state battery (see Figure 5 ) is a sulfide all-solid-state battery, comprising a positive electrode layer, a solid electrolyte layer and a negative electrode layer stacked in sequence.

[0330] Example 1. Preparation of coated silicon-based materials, silicon-containing negative electrode materials, negative electrode films and corresponding sulfide all-solid-state batteries.

[0331] 1.1. Preparation of coated silicon-based materials

[0332] (1) Preparation of sulfide electrolyte material for coating: In an argon-filled glove box, 4.14 g of Li2S, 0.419 g of P2S5 and 9.2 g of SiS2 were weighed into a ball mill, zirconium oxide (ZrO2 ball milling beads) were added, and the resulting precursor mixture was ball milled at 320 r / min for 40 h. The obtained precursor mixture was placed in a carbon crucible and then sealed in a silicone tube. It was then sintered at 600 ° C for 8 h to obtain a sulfide electrolyte (as the first sulfide solid electrolyte) with the chemical formula Li 1.82 SiP 0.036 S3 powder, to be used for coating silicon-based materials.

[0333] The composition of the obtained sulfide solid electrolyte was analyzed by XRD test, and its chemical formula was determined to be Li 1.82 SiP 0.036 S3.

[0334] Measured Li 1.82 SiP 0.036 The ionic conductivity of S3 is 2.4mS / cm, which satisfies "≥0.1mS / cm", "≥0.5mS / cm", and "≥1mS / cm". 1.82 SiP 0.036 The ratio of the Young's modulus of S3 to that of elemental silicon satisfies R E Less than 1, and also satisfies R E Less than or equal to 0.8.

[0335] Li 1.82 SiP 0.036 S3 powder D v 50 and the particle size are both in the range of 0.1 μm to 1 μm.

[0336] (2) Coating: The obtained Li 1.82 SiP 0.036 S3 powder and Si powder (D v 50 is 5 μm) in a weight ratio of 1:50, and then mechanical dry coating is performed to form an electrolyte coating layer on the surface of the Si powder particles, and then sintered at 600 ° C for 6 h to make the coating layer dense, thereby obtaining a coated silicon-based material.

[0337] In this example, in the coated silicon-based material, the silicon base is Si, and the electrolyte coating layer is composed of sulfide electrolyte Li 1.82 SiP 0.036 S3 composition.

[0338] The morphology of the coated silicon-based material was observed using the TEM method, and the thickness of the electrolyte coating layer was about 10 nm.

[0339] 1.2. Preparation of silicon-containing anode materials

[0340] The weight ratio of the coated silicon-based material (Li 1.82 SiP 0.036 The combination of S3 coated Si powder) and binder PVDF is used as the silicon-containing negative electrode material.

[0341] 1.3. Preparation of sulfide all-solid-state batteries.

[0342] 100 mg of sulfide electrolyte LiPSCl powder was weighed and pre-pressed at 100 MPa without holding pressure to obtain a solid electrolyte membrane.

[0343] NCM811 powder, sulfide electrolyte LiPSCl, and conductive carbon fiber (VGCF) were manually ground in a mortar at a weight ratio of 70:28:2 for 10 minutes until they were uniformly mixed to obtain a composite positive electrode powder.

[0344] 18 mg of composite cathode powder was weighed and evenly spread on one side of the solid electrolyte membrane, and cold pressed into a sheet at a pressure of 420 MPa for 5 minutes to form a composite membrane consisting of a cathode layer and a solid electrolyte layer.

[0345] The silicon-containing negative electrode material prepared in step 1.2 was dispersed in the solvent NMP (solid content 60 wt%) and the coating surface density was 2.5 mg / cm 2 Coated on the other side of the solid electrolyte layer in the composite membrane and dried to form a negative electrode layer, a sulfide all-solid-state battery is obtained, which includes a positive electrode layer (corresponding to the positive electrode membrane), a solid electrolyte layer (corresponding to the solid electrolyte membrane) and a negative electrode layer (corresponding to the negative electrode membrane) stacked in sequence.

[0346] Example 2. Changing the D of Silicon-Based Materials v 50

[0347] The coated silicon-based material, silicon-containing negative electrode material, negative electrode film and corresponding sulfide all-solid-state battery were prepared by the same method as in Example 1, except that the silicon-based material was replaced by D v 50 is 1 μm Si powder.

[0348] Example 3. Changing the D of Silicon-Based Materials v 50

[0349] The coated silicon-based material, silicon-containing negative electrode material, negative electrode film and corresponding sulfide all-solid-state battery were prepared by the same method as in Example 1, except that the silicon-based material was replaced by D v 50 is 8 μm Si powder.

[0350] Example 4. Changing the coating amount of the electrolyte coating layer in the coated silicon-based material

[0351] The coated silicon-based material, silicon-containing negative electrode material, negative electrode film and corresponding sulfide all-solid-state battery were prepared by the same method as in Example 1, except that in the coating step, Li 1.82 SiP 0.036 The weight ratio of S3 powder and Si powder was changed to 1:20.

[0352] Example 5. Changing the coating amount of the electrolyte coating layer in the coated silicon-based material

[0353] The coated silicon-based material, silicon-containing negative electrode material, negative electrode film and corresponding sulfide all-solid-state battery were prepared by the same method as in Example 1, except that in the coating step, Li 1.82 SiP 0.036 The weight ratio of S3 powder and Si powder was changed to 1:70.

[0354] Examples 6-7. The coated silicon-based material, silicon-containing negative electrode material, negative electrode film and corresponding sulfide all-solid-state battery are prepared by a method basically the same as that in Example 1, except that the type of silicon base body and coating thickness in the coated silicon-based material are changed.

[0355] Examples 8-9. The coated silicon-based material, silicon-containing negative electrode material and negative electrode film and the corresponding sulfide all-solid-state battery are prepared by a method basically the same as that in Example 1, except that the type and coating thickness of the first sulfide solid electrolyte in the electrolyte coating layer are changed.

[0356] Examples 10-14. The coated silicon-based material, silicon-containing negative electrode material, negative electrode film and corresponding sulfide all-solid-state battery were prepared using a method basically the same as that in Example 1, except that the types and ratios of the components in the silicon-containing negative electrode material were changed.

[0357] Comparative Example 1. No electrolyte coating layer

[0358] The silicon-containing negative electrode material and negative electrode film and the corresponding sulfide all-solid-state battery were prepared by the same method as in Example 1, except that Si powder (D v 50 is 5μm) instead of coated silicon-based materials (Li 1.82 SiP 0.036 S3 coated Si powder).

[0359] Comparative Example 2: No electrolyte coating

[0360] The silicon-containing negative electrode material and negative electrode film and the corresponding sulfide all-solid-state battery were prepared by the same method as in Example 2, except that Si powder (D v 50 is 1μm) instead of coated silicon-based materials (Li 1.82 SiP 0.036 S3 coated Si powder).

[0361] Comparative Example 3. No electrolyte coating layer

[0362] The silicon-containing negative electrode material and negative electrode film and the corresponding sulfide all-solid-state battery were prepared by the same method as in Example 3, except that Si powder (D v 50 is 8μm) instead of coated silicon-based materials (Li1.82 SiP 0.036 S3 coated Si powder).

[0363] Comparative Example 4: Replacing the sulfide solid electrolyte in the electrolyte coating layer with a non-sulfide solid electrolyte LLZTO

[0364] The silicon-containing negative electrode material, negative electrode film and corresponding sulfide all-solid-state battery were prepared by the same method as in Example 1, except that D v 50% approximate lithium lanthanum zirconium tantalum oxide solid electrolyte LLZTO powder instead of sulfide solid electrolyte Li 1.82 SiP 0.036 S3, coating Si powder. Among them, the Young's modulus of LLZTO is higher than that of Si, corresponding to R E >1.

[0365] The relevant parameters of Examples 1-14 and Comparative Examples 1-4 can also be found in Table 1-2.

[0366] Table 1.

[0367]

[0368] Table 2.

[0369]

[0370] 2. Test Method

[0371] (1) Material performance test

[0372] 1. D v 50

[0373] D of particles in solid materials v 50 The following method was used for testing and confirmation: Equipment model: Malvern 2000 (MasterSizer 2000) laser particle size analyzer, reference standard process: GB / T19077-2016 / ISO 13320:2009, specific test process: take an appropriate amount of the sample to be tested (the sample concentration is guaranteed to be 8%-12% (w / v) shading), add 20mL of solvent, and simultaneously operate externally for 5min (53KHz / 120W) to ensure that the sample is completely dispersed, and then measure the sample according to GB / T19077-2016 / ISO 13320:2009 standard.

[0374] Test the D of particles in the sulfide electrolyte material used for coating v The solvent used in 50 can be xylene.

[0375] Testing D of silicon-based materials v The solvent used in 50 can be deionized water.

[0376] 2. XRD test instrument and parameters: D8 Advance Da Vinci X, Cu Kα1, scanning range 20°-110°, scanning speed 5° / min.

[0377] It can be used to confirm the structure and composition of the prepared sulfide electrolyte material for coating.

[0378] 3. The transmission electron microscope (TEM) is a FEI / Talos F200X instrument with a test acceleration voltage of 200 kV. This instrument integrates high-resolution scanning / transmission electron microscopy (STEM) and TEM imaging capabilities, as well as energy-dispersive X-ray spectroscopy (EDS) signal detection and three-dimensional chemical characterization based on compositional mapping.

[0379] The coating structure and coating layer composition of coated silicon-based materials can be tested and analyzed.

[0380] 4. Young's modulus

[0381] Samples: First sulfide solid electrolyte and silicon powder. The electrolyte material is dispersed on a silicon wafer using NMP and then dried for testing. The silicon powder is dispersed on a silicon wafer using deionized water and then dried for testing.

[0382] The Young's modulus of a solid electrolyte can be measured using an atomic force microscope (AFM, Dimension icon / DimensioniconXR, equipped with a QNM module). The shear modulus under different pressures can be measured and the average Young's modulus can be obtained by fitting the pressure and shear modulus data. This value can be used as the "Young's modulus" test value in this application.

[0383] 5. Ionic conductivity test of solid electrolyte materials

[0384] The ionic conductivity was measured by electrochemical impedance spectroscopy (EIS). The detailed process is as follows: 120 mg of solid electrolyte powder was poured into a 10 mm diameter tablet mold and pressed into a dense disc at 360 MPa. Then, a 10 mm diameter cylindrical stainless steel current collector was used to clamp the solid electrolyte membrane in the mold at 120 MPa. The current collector was then connected to an electrochemical workstation and tested at a bias voltage of 10 mV and a frequency range of 10 6 Electrochemical impedance spectroscopy (EIS) is performed on solid electrolyte membranes in the range of Hz to 10Hz. The intersection of the curve from the high frequency band to the low frequency band in the electrochemical impedance spectrum and the Z' axis is recorded as the resistance value R. The ionic conductivity can be calculated using formula (1):

[0385]

[0386] Where d is the thickness of the solid electrolyte membrane, and A is the contact area between the solid electrolyte membrane and the current collector.

[0387] (2) Battery performance test

[0388] The electrochemical performance of the negative electrode and the corresponding all-solid-state battery was tested using a solid-state mold battery, and the battery test window was 4.3 to 2.0 V (versus lithium potential).

[0389] 1. First discharge capacity

[0390] The test process is as follows: the assembled all-solid-state battery is charged to 4.3V at a current density of 0.1C, allowed to rest for 10 minutes, and then discharged to 2.0V at a current density of 0.1C to obtain the battery's initial discharge capacity. The battery is tested at 25±3°C, where 0.1C = 200mA / g.

[0391] 2. First Coulombic efficiency

[0392] The first coulombic efficiency of the battery can be obtained by dividing the first discharge capacity obtained by the first charge capacity tested at 0.1C.

[0393] 3. Rate performance

[0394] The test process is as follows: the charge rate of the all-solid-state battery is fixed at 0.1C, and then discharged at the rates of 0.1C, 0.33C, 1C, 2C, and 3C, respectively. Each rate is cycled 3 times. The battery voltage test window is 4.3~2.0V vs.Li + / Li, the battery was tested at 25±3°C, where 1C=200mA / g.

[0395] 4. Cycle performance

[0396] The assembled all-solid-state battery was first charged and discharged for 3 cycles at a current density of 0.1C to obtain the initial discharge capacity and initial coulombic efficiency. Then, a long cycle test was performed at a current density of 0.33C for 100 cycles to calculate the battery's cycle capacity retention rate. The battery's voltage test window is 4.3~2.0V vs.Li + / Li, the battery was tested at 25±3°C, where 1C=200mA / g.

[0397] 3. Test Analysis Results

[0398] The test results of Examples 1-14 and Comparative Examples 1-4 can be found in Table 3.

[0399] The sulfide solid-state batteries prepared in each embodiment have good discharge capacity, rate performance and cycle performance, and also have good first coulombic efficiency.

[0400] Comparative Examples 1-3 do not have the electrolyte coating layer in the present application. Compared with Examples 1-3, the discharge capacity, rate performance and cycle performance of Comparative Examples 1-3 are significantly deteriorated, especially the cycle capacity retention rate is seriously reduced, which seriously affects the cycle stability. In addition, the first coulombic efficiency is also significantly reduced.

[0401] In Comparative Example 4, for the coating material, the non-sulfide solid electrolyte LLZTO was used instead of the first sulfide solid electrolyte in Example 1 to coat the Si powder. The first coulombic efficiency, discharge capacity, rate performance and cycle performance were also significantly deteriorated. The Young's modulus of the LLZTO electrolyte is higher than that of Si(R E >1), which cannot buffer the volume expansion of the silicon matrix, resulting in poor interface contact of the negative electrode layer, which in turn leads to a significant deterioration in discharge capacity, rate performance and cycle performance, and also leads to a significant decrease in the first coulombic efficiency.

[0402] Table 3.

[0403]

[0404]

[0405] The description of each embodiment above tends to emphasize the differences between the embodiments, and the same or similar aspects can be referenced to each other. For the sake of brevity, this article will not go into details. The technical features of the embodiments described above can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples. Within the scope of the technical solution of this application, embodiments with essentially the same composition as the technical idea and the same effect are included in the technical scope of this application. The embodiments described above only express several embodiments of the present application, and the description is relatively detailed, but it cannot be understood as a limitation on the scope of the patent. In addition, without departing from the scope of the main purpose of this application, other methods of applying various modifications that can be thought of by those skilled in the art to the embodiments and combining some of the constituent elements in the embodiments are also included in the scope of this application.

Claims

1. A silicon-containing negative electrode material, characterized in that: The coated silicon-based material comprises a silicon base body and an electrolyte coating layer coating at least a portion of the surface of the silicon base body; the electrolyte coating layer contains a sulfide solid electrolyte.

2. A silicon-containing negative electrode material, characterized in that: The coated silicon-based material comprises a silicon base body and an electrolyte coating layer coated on at least a portion of the surface of the silicon base body; the electrolyte coating layer comprises a sulfide solid electrolyte; Wherein, in the coated silicon-based material, under the test condition of 20°C, the ionic conductivity of the sulfide solid electrolyte is greater than or equal to 0.1 mS / cm, and under the test condition of 30°C, the ratio of the Young's modulus of the sulfide solid electrolyte to the silicon base body is less than 1; Optionally, under test conditions at 20° C., the ionic conductivity of the sulfide solid electrolyte is greater than or equal to 0.5 mS / cm; further optionally, under test conditions at 20° C., the ionic conductivity of the sulfide solid electrolyte is greater than or equal to 1 mS / cm; Optionally, under test conditions at 30° C., a ratio of the Young's modulus of the sulfide solid electrolyte to that of the silicon matrix is ​​less than or equal to 0.

8.

3. The silicon-containing negative electrode material according to claim 1 or 2, characterized in that: The sulfide solid electrolyte includes a Li2S–SiS2–P2S5 ternary sulfide electrolyte; Optionally, in the Li2S–SiS2–P2S5 ternary sulfide electrolyte, the atomic molar ratio of Li element to Si element is denoted as R Li / Si The atomic molar ratio of P element to Si element is denoted as R P / Si , 1.80 <R Li / Si <1.84, 10.34 <R P / Si <0.38; Further optionally, the Li2S-SiS2-P2S5 ternary sulfide electrolyte includes Li 1.82 SiP 0.036 S3.

4. The silicon-containing negative electrode material according to claim 1 or 2, characterized in that The silicon base body includes one or more of elemental silicon, silicon-carbon composite, silicon oxide and silicon-carbon composite; Optionally, the silicon matrix includes a silicon-carbon composite, and the silicon-carbon composite includes a porous carbon matrix and nano-silicon located in the pores of the porous carbon matrix.

5. The silicon-containing negative electrode material according to any one of claims 1 to 4, characterized in that The coated silicon-based material meets one or more of the following characteristics: In the coated silicon-based material, the weight ratio of the sulfide solid electrolyte to the silicon base body is 1:(20-70), and can be optionally 1:(45-55); The weight proportion of the sulfide solid electrolyte in the coated silicon-based material is 1 wt% to 5 wt%, and can be optionally 1.5 wt% to 2.5 wt%; The thickness of the electrolyte coating layer is 1 nm to 100 nm, and can be optionally 10 nm to 50 nm.

6. The silicon-containing negative electrode material according to any one of claims 1 to 5, characterized in that The D of the silicon base body v 50 or the particle size is less than or equal to 50 μm, and can be selected from 1 μm to 50 μm, further selected from 1 μm to 8 μm, and further selected from 4 μm to 6 μm.

7. The silicon-containing negative electrode material according to any one of claims 1 to 6, characterized in that The electrolyte coating layer includes dot-shaped particles of the sulfide solid electrolyte; Optionally, the particle size of the dot-shaped particles of the sulfide solid electrolyte is less than or equal to 1 μm, and can be optionally 0.1 μm to 1 μm.

8. The silicon-containing negative electrode material according to any one of claims 1 to 7, characterized in that: In at least a portion of the coated silicon-based material, the sulfide solid electrolyte is distributed discontinuously on the surface of the silicon base body.

9. The silicon-containing negative electrode material according to any one of claims 1 to 8, characterized in that The weight proportion of the coated silicon-based material in the silicon-containing negative electrode material is greater than or equal to 50 wt %, and may be 50 wt % to 99 wt %, and further may be 85 wt % to 97 wt %.

10. The silicon-containing negative electrode material according to any one of claims 1 to 9, characterized in that Also including or not including a blended solid electrolyte; Optionally, the blended solid electrolyte includes a blended sulfide solid electrolyte; Further optionally, the blended solid electrolyte includes thio-LISICON, Li6PS5Cl, Li 10 SnP2S 12 , one or more of Li2S-P2S5 binary sulfur-based electrolyte, Li2S-SiS2 binary sulfur-based electrolyte and Li2S-B2S3 binary sulfur-based electrolyte.

11. The silicon-containing negative electrode material according to claim 10, characterized in that The weight proportion of the blended solid electrolyte in the silicon-containing negative electrode material is 0 wt% to 30 wt%, and can be optionally 0.5 wt% to 5 wt%.

12. The silicon-containing negative electrode material according to any one of claims 1 to 11, characterized in that The silicon-containing negative electrode material meets one or more of the following characteristics: The silicon-containing negative electrode material may or may not include a negative electrode conductive agent; optionally, the weight proportion of the negative electrode conductive agent in the silicon-containing negative electrode material is 0 wt% to 10 wt%, optionally 0.1 wt% to 10 wt%, further optionally 0.1 wt% to 2 wt%; The silicon-containing negative electrode material includes a negative electrode binder; optionally, the weight proportion of the negative electrode binder in the silicon-containing negative electrode material is 0.1 wt% to 20 wt%, and further optionally 1 wt% to 10 wt%.

13. A method for preparing a coated silicon-based material, characterized in that: The steps include: The sulfide solid electrolyte is physically mixed with a silicon base body, and then sintered to form an electrolyte coating layer containing the sulfide solid electrolyte on at least a portion of the surface of the silicon base body, thereby preparing a coated silicon-based material.

14. The method for preparing the coated silicon-based material according to claim 13, characterized in that: The sulfide solid electrolyte is as defined in claim 2 or 3.

15. The method for preparing the coated silicon-based material according to claim 13 or 14, characterized in that: Meet one or more of the following characteristics: In the step of physically blending the sulfide solid electrolyte with the silicon matrix, the weight ratio of the sulfide solid electrolyte to the silicon matrix is ​​1:(20-70), and can be optionally 1:(45-55); The method for performing the physical blending is dry blending; The sintering atmosphere for the sintering is argon; The sintering temperature is 550°C to 650°C, and can be 580°C to 620°C. The sintering time is 6 hours to 10 hours.

16. The method for preparing the coated silicon-based material according to any one of claims 13 to 15, characterized in that: The sulfide solid electrolyte is prepared by a method comprising the following steps: The precursor raw materials of the sulfide solid electrolyte are mixed, ball-milled, and sintered in a sealed state to obtain the sulfide solid electrolyte.

17. The method for preparing the coated silicon-based material according to claim 16, characterized in that: Meet one or more of the following characteristics: The ball milling is performed by dry ball milling; The ball milling beads used for the ball milling include zirconium oxide ball milling beads; The ball milling is performed at a rotation speed of 300 rpm to 400 rpm, and can be optionally 300 rpm to 350 rpm; The ball milling is performed for 36 to 48 hours.

18. The method for preparing a coated silicon-based material according to any one of claims 13 to 17, characterized in that: The coated silicon-based material is the coated silicon-based material in the silicon-containing negative electrode material according to any one of claims 1 to 12.

19. A negative electrode film, characterized in that The negative electrode active material layer comprises a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector, wherein the negative electrode active material layer comprises the silicon-containing negative electrode material according to any one of claims 1 to 12.

20. The negative electrode film according to claim 19, characterized in that The negative electrode film is an all-solid-state negative electrode film.

21. A solid-state battery, characterized in that: Comprising the negative electrode film according to claim 19 or 20.

22. The solid-state battery according to claim 21, characterized in that The solid-state battery is a sulfide all-solid-state battery.

23. The solid-state battery according to claim 21 or 22, characterized in that: The solid-state battery is a lithium-ion solid-state battery.

24. An electrical device, characterized in that: The invention comprises at least one of the negative electrode film according to claim 19 or 20 and the solid-state battery according to any one of claims 21 to 23.

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