Sulfide solid electrolyte and preparation method therefor, solid electrolyte membrane, electrode sheet, solid-state battery, and electric device

Abstract

The present application relates to a sulfide solid electrolyte and a preparation method therefor, a solid electrolyte membrane, an electrode sheet, a solid-state battery, and an electric device. The sulfide solid electrolyte comprises an argyrodite-type crystal phase; the argyrodite-type crystal phase comprises Li, P, S, M and T elements, wherein the M element is selected from one or both of Se and Te elements, and the T element is selected from one or both of Cl and Br elements; in the argyrodite-type crystal phase, an atomic number ratio of the T element to the P element is recorded as 1+x, and x>0; and in the argyrodite-type crystal phase, an atomic number ratio of the M element to the P element is recorded as y, and y>0.

Description

Sulfide solid electrolyte, preparation method thereof, solid electrolyte membrane, electrode sheet, solid-state battery and electric device

[0001] Related Applications

[0002] The present application claims priority to the Chinese patent application No. CN2024104376205, filed on April 11, 2024, entitled "Sulfide solid electrolyte, preparation method thereof, solid electrolyte membrane, electrode sheet, solid-state battery and electric device", the contents of which are hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of secondary batteries, further relates to the technical field of solid-state batteries, and more further relates to a sulfide solid electrolyte, a preparation method thereof, a solid electrolyte membrane, an electrode sheet, a solid-state battery and an electric device. BACKGROUND

[0004] The statements herein are provided only to enhance understanding of the present application and are not necessarily prior art.

[0005] Solid-state batteries introduce non-flammable solid electrolytes to replace organic electrolytes in conventional liquid secondary batteries, which greatly improves the safety of the batteries. Among a large number of solid electrolyte materials, sulfide solid electrolytes have become the most practical and industrialized solid electrolyte material due to their ultra-high ionic conductivity and excellent mechanical properties. As a kind of sulfide solid electrolyte, the sintered product of argyrodite-type sulfide solid electrolyte often cannot achieve the expected ionic conductivity, which further leads to unsatisfactory discharge capacity and rate performance of the solid-state battery. SUMMARY

[0006] According to various embodiments and various examples of the present application, the present application provides a sulfide solid electrolyte, a preparation method thereof, a solid electrolyte membrane, an electrode sheet, a solid-state battery and an electric device. The sulfide solid electrolyte has a high ionic conductivity, which can effectively improve the rate performance of the solid-state battery.

[0007] In a first aspect of the present application, a sulfide solid electrolyte is provided, comprising an argyrodite-type crystal phase;

[0008] The argyrodite-type crystal phase comprises Li element, P element, S element, M element and T element; wherein the M element is selected from one or both of Se element and Te element, and the T element is selected from one or both of Cl element and Br element;

[0009] In the argyrodite-type crystal phase, the atomic number ratio of the T element to the P element is denoted as 1+x, and x>0;

[0010] In the argyrodite-type crystal phase, an atomic ratio of the M element to the P element is denoted as y, and y > 0.

[0011] The sulfide solid electrolyte provided in the first aspect of the present application is an argyrodite-type sulfide solid electrolyte including an argyrodite-type crystal phase containing a Li element, a P element, an S element, and a T element (the T element being one or both of a Cl element and a Br element). In a case where an atomic ratio (1 + x) of the T element to the P element is greater than 1 (x > 0 at this time), by introducing an M element (which can be one or both of a Se element and a Te element), on the one hand, more lithium vacancies can be generated by the excess T element. On the other hand, the smaller Coulombic binding force of the T element to lithium ions can facilitate the migration of lithium ions, which is conducive to promoting the diffusion of lithium ions and improving the ionic conductivity of the solid electrolyte. On the other hand, the M element can compensate for the loss of sulfur (S) of the sulfide raw material during the sintering process, can inhibit the generation of LiT and other impurities, and is also conducive to improving the ionic conductivity of the solid electrolyte. On the other hand, the ionic radius of the M element is larger than that of the S element, which can widen the ion transport channel in the crystal structure. The aforementioned multiple synergistic effects can significantly improve the ionic conductivity of the argyrodite-type sulfide solid electrolyte.

[0012] When the sulfide solid electrolyte is used as a solid electrolyte material in a solid-state battery, it can be used as a solid electrolyte material in one or more structural layers of a solid electrolyte layer, a positive electrode layer, and a negative electrode layer, which can effectively reduce the resistance of the solid-state battery and improve the rate performance of the solid-state battery, and can enable the solid-state battery to have better electrochemical performance at high rates.

[0013] When the sulfide solid electrolyte is used as a positive electrode electrolyte particle in the positive electrode layer, it can also promote the capacity of the positive electrode active material in the positive electrode layer.

[0014] When the sulfide solid electrolyte is used as a positive electrode electrolyte particle in the positive electrode layer, it can also promote the capacity of the positive electrode active material in the positive electrode layer.

[0015] In some embodiments, in the argyrodite-type crystal phase, 0 < x ≤ 0.8.

[0016] By controlling x within the aforementioned range, the T element can be controlled within a more optimal range, which is conducive to better improving the ionic conductivity of the sulfide solid electrolyte, and can also simultaneously control the content of impurities at a lower proportion.

[0017] In some embodiments, in the argyrodite-type crystal phase, 0 < y ≤ 0.1.

[0018] By controlling y within the aforementioned range, the M element can be controlled within a more optimal range, which is more conducive to inhibiting impurities and improving the ionic conductivity of the sulfide solid electrolyte.

[0019] In some embodiments, in the argyrodite-type crystal phase, the atomic number ratio of Li element, P element, S element, M element and T element is (6-x):1:(5-x-y):y:(1+x), wherein 0

[0020] In some embodiments, the chemical formula of the argyrodite-type crystal phase is Li 6-x PS 5-x-y M y T 1+x .

[0021] When the argyrodite-type crystal phase has the aforementioned chemical formula, it is beneficial to better inhibit the impurity phase and better improve the ionic conductivity of the sulfide solid electrolyte.

[0022] In some embodiments, the chemical formula of the argyrodite-type crystal phase is Li 6-x PS 5-x-y Se y Cl 1+x .

[0023] When the M element includes Se element and the T element includes Cl element, it is beneficial for the sulfide solid electrolyte to have more optimal ionic conductivity.

[0024] In some embodiments, the argyrodite-type crystal phase satisfies one or more of the following characteristics:

[0025] In the argyrodite-type crystal phase, 0.05≤x≤0.8; optionally, 0.1≤x≤0.8; further optionally, 0.3≤x≤0.8;

[0026] In the argyrodite-type crystal phase, 0.02≤y≤0.1; optionally, 0.02≤y≤0.09.

[0027] In some embodiments, 0.3≤x≤0.8, 0.02≤y≤0.09.

[0028] By controlling one or both of x and y parameters in the aforementioned range, the T element and the M element can have a more suitable content, which is beneficial to better improve the ionic conductivity of the sulfide solid electrolyte. By controlling y in the aforementioned range, the M element can be controlled in a more optimal range, which is more beneficial to inhibit the impurity phase and improve the ionic conductivity of the sulfide solid electrolyte.

[0029] In some embodiments, in the argyrodite-type crystal phase, the atomic number ratio of S element to P element is 5-x-y, and 4.1≤(5-x-y)<5.0.

[0030] In some embodiments, 4.1 < (5-x-y) < 4.7.

[0031] When the atomic ratio of S element to P element (5-x-y) is controlled within the aforementioned range, by controlling the contents of x and y, it is more advantageous to suppress the formation of impurities and to improve the ionic conductivity of the sulfide solid electrolyte.

[0032] In some embodiments, the argyrodite-type crystal phase satisfies one or both of the following characteristics:

[0033] In the argyrodite-type crystal phase, the T element includes a Cl element;

[0034] In the argyrodite-type crystal phase, the M element includes a Se element.

[0035] When the M element includes a Se element, it is advantageous for the sulfide solid electrolyte to have more excellent ionic conductivity.

[0036] When the T element includes a Cl element, it is advantageous for the sulfide solid electrolyte to have more excellent ionic conductivity.

[0037] In some embodiments, the argyrodite-type crystal phase satisfies one or both of the following characteristics:

[0038] In the argyrodite-type crystal phase, the atomic ratio of Cl element to Br element is greater than or equal to 1;

[0039] In the argyrodite-type crystal phase, the atomic ratio of Se element to Te element is greater than or equal to 1.

[0040] By providing one or both of the characteristics of "the atomic ratio of Cl element to Br element is greater than 1" and "the atomic ratio of Se element to Te element is greater than 1", it is more advantageous to improve the ionic conductivity of the sulfide solid electrolyte.

[0041] In some embodiments, the argyrodite-type crystal phase has any one of the following chemical formulas: Li 5.7 PS 4.65 Se 0.05 Cl 1.3 , Li 5.5 PS 4.44 Se 0.06 Cl1Br 0.5 , Li 5.5 PS 4.44 Se 0.05 Te 0.01 Cl1Br 0.5 and Li 5.5 PS 4.44 Se 0.06 Cl1.5 .

[0042] By disposing one or more argyrodite-type crystal phases in the sulfide solid electrolyte, the impurity phase can be reduced and the ionic conductivity can be improved.

[0043] In some embodiments, the sulfide solid electrolyte has characteristic peaks in the 2θ (°) diffraction angles in the X-ray diffraction pattern thereof corresponding to the argyrodite-type crystal phase.

[0044] In some embodiments, the sulfide solid electrolyte satisfies at least one of the following characteristics:

[0045] The sulfide solid electrolyte has peaks in the 2θ (°) diffraction angles in the X-ray diffraction pattern thereof at 15.5±δ°, 18.1±δ°, 25.6±δ°, 30.1±δ°, 31.4±δ°, 39.8±δ°, 45.1±δ°, 47.9±δ°, and 52.5±δ°, wherein δ is 0.2 or 0.1;

[0046] The sulfide solid electrolyte has no LiT impurity phase peak in the X-ray diffraction pattern thereof;

[0047] The sulfide solid electrolyte has no diffraction peaks in the 2θ (°) diffraction angles in the X-ray diffraction pattern thereof at 34.9±0.2°, 29.2±0.2°, and 33.9±0.2°;

[0048] The X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα rays;

[0049] The X-ray diffraction pattern of the sulfide solid electrolyte is obtained by powder X-ray diffraction testing.

[0050] The chemical composition and the amount of impurity phase in the sulfide solid electrolyte can be confirmed by X-ray diffraction (XRD) detection.

[0051] In a second aspect of the present application, a preparation method of a sulfide solid electrolyte is provided, which can be used to prepare the sulfide solid electrolyte of the first aspect of the present application.

[0052] In some embodiments, the preparation method of the sulfide solid electrolyte comprises the following steps:

[0053] A precursor mixture comprising Li2S, P2S5, optional elemental sulfur, elemental M, and LiT is provided according to the stoichiometric ratio of the required raw materials; wherein the elemental M is selected from one or both of elemental Se and elemental Te, T is a halogen, and LiT is selected from one or both of LiCl and LiBr;

[0054] sintering the precursor mixture in an inert atmosphere to prepare a sulfide solid electrolyte including a argyrodite-type crystal phase, in which the argyrodite-type crystal phase satisfies x > 0 and y > 0.

[0055] In some embodiments, the method for preparing the sulfide solid electrolyte satisfies one or more of the following features:

[0056] In the step of sintering the precursor mixture in an inert atmosphere, the sintering temperature is 450°C to 530°C;

[0057] The prepared sulfide solid electrolyte is the sulfide solid electrolyte according to the first aspect of the present application.

[0058] In the third aspect of the present application, a solid electrolyte film is provided, which includes at least one of the sulfide solid electrolyte according to the first aspect of the present application and the sulfide solid electrolyte prepared by the method according to the second aspect of the present application.

[0059] For the solid electrolyte film provided with the aforementioned sulfide solid electrolyte, the internal resistance can be effectively reduced, and the corresponding solid-state battery can be endowed with better rate performance and better electrochemical performance at high rates.

[0060] In the fourth aspect of the present application, an electrode tab is provided, which includes an electrode active material layer including an electrode active substance and at least one of the sulfide solid electrolyte according to the first aspect of the present application and the sulfide solid electrolyte prepared by the method according to the second aspect of the present application.

[0061] In some embodiments, the electrode tab is a positive electrode tab, the electrode active material layer is referred to as a positive electrode active material layer, and the electrode active substance is referred to as a positive electrode active substance.

[0062] Alternatively, the electrode tab is a negative electrode tab, the electrode active material layer is referred to as a negative electrode active material layer, and the electrode active substance is referred to as a negative electrode active substance.

[0063] For the electrode tab provided with the aforementioned sulfide solid electrolyte, the internal resistance of the tab can be reduced, the capacity of the active substance in the tab can be promoted, and the corresponding solid-state battery can be endowed with better rate performance.

[0064] The electrode tab can be a positive electrode tab or a negative electrode tab.

[0065] In a fifth aspect of the present application, a solid-state battery is provided, which comprises at least one of the sulfide solid electrolyte of the first aspect of the present application, the sulfide solid electrolyte prepared by the preparation method of the second aspect of the present application, the solid electrolyte film of the third aspect of the present application, and the electrode tab of the fourth aspect of the present application.

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

[0067] For the solid-state battery provided with the aforementioned sulfide solid electrolyte, the sulfide solid electrolyte can be provided at one or more of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer.

[0068] In a sixth aspect of the present application, an electric device is provided, which comprises at least one of the sulfide solid electrolyte of the first aspect of the present application, the sulfide solid electrolyte prepared by the preparation method of the second aspect of the present application, the solid electrolyte film of the third aspect of the present application, the electrode tab of the fourth aspect of the present application, and the solid-state battery of the fifth aspect of the present application.

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

[0070] In order to better describe and illustrate the embodiments, examples or examples provided by the present application, one or more drawings can be referred to. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any one of the disclosed applications, the presently described embodiments, examples or examples, and the best mode of these applications currently understood. It should be noted that the drawings are all drawn in a simplified form, only for the convenience, clarity of the description of the present application. The various sizes of each component shown in the drawings are arbitrarily shown, which can be accurate or not drawn according to the actual proportion. For example, in order to make the drawing clearer, the size of some components in the drawing is appropriately exaggerated. Unless otherwise specified, the components in the drawing are not drawn to scale. The drawings of the present application do not limit the size of each component. Moreover, the same reference numerals are used to represent the same components in all the drawings. In the drawings:

[0071] Figure 1 is a schematic view of the structure of a solid-state battery cell according to an embodiment of the present application, which comprises a positive electrode layer, a solid electrolyte layer and a negative electrode layer stacked in sequence.

[0072] Figure 2 is a schematic view of a solid-state battery cell according to an embodiment of the present application.

[0073] Figure 3 is an exploded view of the solid-state battery cell shown in Figure 2 according to an embodiment of the present application.

[0074] FIG4 is a schematic diagram of a battery module according to an embodiment of the present application.

[0075] FIG5 is a schematic diagram of a battery pack according to an embodiment of the present application.

[0076] FIG6 is an exploded view of the battery pack shown in FIG5 according to an embodiment of the present application.

[0077] FIG7 is a schematic diagram of an electrical device using a solid-state battery as a power source according to an embodiment of the present application.

[0078] FIG8 is an X-ray diffraction (XRD) diagram of the sulfide solid electrolytes prepared in Example 8 and Comparative Example 3 of the present application, where the abscissa is 2θ (unit: degree, which can be expressed as °) and the ordinate is intensity.

[0079] Explanation of the accompanying drawings: 100, solid electrolyte layer; 200, positive electrode layer; 300, negative electrode layer; 1, battery pack; 2, upper case; 3, lower case; 4, battery module; 5, solid-state battery cell; 51, shell; 52, solid-state battery cell; 53, cover plate; 6, electrical device. DETAILED DESCRIPTION

[0080] Below, some embodiments of the sulfide solid electrolyte and its preparation method, solid electrolyte membrane, electrode plate, solid-state battery, electrical device, etc. 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 may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0081] The ranges disclosed herein can be limited by both a lower limit and an upper limit, to define a particular range by selecting a lower limit and an upper limit, the selected lower limit and upper limit define the boundaries of the particular range. Ranges defined by such limits can be either inclusive or exclusive of the end values, either end value can be included or excluded independently, and can be combined in any manner, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. In addition, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are also listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise indicated, a numerical range "a-b" indicates a shorthand way of describing each and every intervening real number, integer or combination of integers between the upper and lower limits of that range, in which "a" and "b" are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed herein, "0-5" is merely a shorthand way of describing those numerical combinations. In addition, when a parameter is stated to be an integer ≥ 2, it is equivalent to listing the parameter as, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is stated to be an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0082] In this application, unless otherwise specified, "about" means within a reasonable range, the fluctuation range can vary depending on the type and value of the number. For example, it can be allowed within a range of ±10%, ±5%, ±2%, ±1%, etc. For example, taking "about 20°C" and its approximation ±1°C as an example, the approximation values of 19°C, 19.5°C, etc. within the approximation range indicated by "about 20°C" should also be included in the range indicated by "about 20°C".

[0083] In this application, unless otherwise specified, "a plurality of", "a plurality of", "a plurality of", "several", etc. means more than 2 or equal to 2 in quantity. For example, "one or more" means one or ≥(greater than or equal to) two. It can be understood that when referring to "any number of" items, it means any suitable combination of a plurality of items, i.e., in a manner that does not conflict and can implement the present application.

[0084] If not specifically stated, all embodiments and optional embodiments of the present application can be combined to form new technical solutions.

[0085] Reference to "an embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all referring to a common embodiment, or an embodiment that is independent of other embodiments. One of ordinary skill in the art will recognize that an implementation including "an embodiment" or "one embodiment" can include more than one embodiment and that the disclosure of "an embodiment" or "one embodiment" should not necessarily be construed to be limited to that single implementation.

[0086] Those skilled in the art can understand that the order of the steps in the methods of various embodiments or examples does not mean strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. If not specifically stated, all steps of the application can be performed sequentially or randomly, and can be preferably performed sequentially. For example, method M includes steps (a) and (b), which means that the method can include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, method M also includes step (c), which means that step (c) can be added to method M in any order, for example, method M can include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0087] In the present application, the open technical features or technical solutions described by "containing", "including", "comprising" and the like, if not otherwise stated, do not exclude additional members from the listed members, which can be considered to provide not only the closed features or solutions composed of the listed members, but also the open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2 and a3, if not otherwise stated, it can also include other members, or it can not include additional members, which can be considered to provide the feature or solution that "A is composed of a1, a2 and a3" or "A is selected from a1, a2 and a3", and also provides the feature or solution that "A includes a1, a2 and a3, and also includes other members".

[0088] In the present application, A (such as B) means that B is a non-limiting example of A, and A can be understood as not limited to B, if not otherwise stated.

[0089] In the present application, "optionally", "optional" and "optional" mean optional, i.e. selected from "yes" or "no" in two parallel solutions. If there are multiple "optional" in a technical solution, if not otherwise stated, and there is no contradictory relationship or mutual restriction, each "optional" is independent. If not otherwise stated, "optionally includes", "optionally contains" and the like are described in the present application, for example, "optionally includes" means "may include or not include".

[0090] In the present application, “and / or” corresponds to any one of two or more related listed items, or any and all combinations of the related listed items, unless otherwise specified, wherein any and all combinations include any two related listed items, any more related listed items, or all related listed items. For example, “A and / or B” represents a group consisting of A, B, and a combination of A and B. Wherein “including A and / or B” can mean “including A, including B, and including A and B”, or can mean “including A, including B, or including A and B”, which can be properly understood according to the sentence.

[0091] As used herein, “combinations thereof”, “any combination thereof”, “any combination manner thereof” and the like include all suitable combination manners of any two or more of the listed items.

[0092] As used herein, “suitable combination manner”, “suitable manner”, “any suitable manner” and the like, “suitable” is subject to the implementation of the technical solutions of the present application.

[0093] As used herein, “preferably”, “better”, “more preferably”, “suitably”, “more preferably”, “more preferably” only describe the implementation manner or embodiment with better effect, and it should be understood that it does not constitute a limitation on the protection scope of the present application. If there are multiple “preferably” in a technical solution, each “preferably” is independent of each other, unless otherwise specified, and there is no contradictory relationship or mutual restriction.

[0094] In the present application, “further”, “more further”, “in particular”, “for example”, “such as”, “example”, “for example” are used for description purposes, indicating differences in content, but should not be understood as limiting the protection scope of the present application.

[0095] In the present application, “first aspect”, “second aspect”, “third aspect”, “fourth aspect”, “fifth aspect”, “sixth aspect” and the like, the terms “first”, “second”, “third”, “fourth”, “fifth”, “sixth” and the like are only used for description purposes, and should not be understood as indicating or implying relative importance or quantity, nor should it be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, “first”, “second”, “third”, “fourth”, “fifth”, “sixth” and the like only serve the purpose of non-exhaustive enumeration and description, and should be understood as not constituting a closed limitation on the quantity.

[0096] In the present application, unless specifically stated and limited otherwise, a first feature is "on" or "under" a second feature can mean that the first and second features are in direct contact, or the first and second features are in indirect contact via an intermediate medium. In the present application, unless specifically stated and limited otherwise, a first feature is "on" or "under" a second feature can mean a horizontal height reciprocal position relationship, or can only mean an attachment relationship without limiting the horizontal height reciprocal position relationship.

[0097] In the present application, the term "room temperature" generally refers to 4℃ to 35℃, and can refer to 20℃±5℃. In some embodiments or examples of the present application, room temperature refers to 20℃ to 30℃.

[0098] In the present application, the units related to the data range, if only the right end point is followed by a unit, it means that the units of the left end point and the right end point are the same. For example, 3-5h or 3-5h means that the units of the left end point "3" and the right end point "5" are both h (hours), which have the same meaning as 3h-5h. In addition, similar descriptions of other parameters such as temperature and size are also understood in the same way.

[0099] The weight or mass of the related 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 between the weight or mass of each component. Therefore, as long as the content of the related components in the embodiments or examples of the present application is enlarged or reduced in proportion, 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 micrograms (μg), milligrams (mg), grams (g), kilograms (kg), and other mass units known in the chemical field. Unless otherwise specified, the mass ratio is equal to the corresponding weight ratio, for example, the mass of substance A is m1, the weight is W1, the mass of substance B is m2, and the weight is W2. The mass ratio m1 / m2 is numerically equal to the corresponding weight ratio W1 / W2.

[0100] In the present application, unless otherwise specified, wt% represents the weight percentage by weight, which is numerically equal to the corresponding mass percentage by mass. In the present application, for the weight percentage, "0" has the same meaning as "0wt%" and can be used interchangeably.

[0101] In the present application, unless otherwise specified, nm represents nanometer, μm represents micrometer, S / cm represents siemens per centimeter, V represents volt, kV represents kilovolt, mA represents milliampere, Hz represents hertz, mPa·S represents millipascal·second, mg / cm 2 represents milligrams per square centimeter, g / cm 2 represents grams per square centimeter, g / cm 3 represents grams per cubic centimeter, and ℃ represents Celsius.

[0102] In the present 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 equivalent to “>”, and “less than” can be equivalent to “<”. In the present application, unless otherwise specified, “greater than or equal to” and “≥” can be considered to provide both “greater than” and “equal to” options. In the present application, unless otherwise specified, “less than or equal to” and “≤” can be considered to provide both “less than” and “equal to” options.

[0103] In the present application, exemplary descriptions involving “in some embodiments (or examples)”, “in an embodiment (or example)” and the like can cover, but are not limited to, the following meanings: these options can be combined with other options in a suitable manner to form new technical solutions.

[0104] In the present application, unless otherwise specified, the “solid-state battery” provided in the present application refers to a battery in which the electrolyte in the battery comprises a solid electrolyte; generally, a solid-state battery comprises a positive electrode layer, a solid electrolyte layer and a negative electrode layer. During the charging and discharging process of the battery, active ions are embedded and extracted between the positive electrode layer and the negative electrode layer. The solid electrolyte layer plays a role in 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 short circuiting of the positive and negative electrodes, therefore, the solid-state battery can not be provided with a separator film in a traditional lithium-ion battery. The introduction of non-flammable solid electrolyte in the solid-state battery instead of organic electrolyte in the traditional liquid lithium-ion battery greatly improves the safety of the battery. In addition to improving safety, solid-state batteries can also better adapt to high-energy-density positive and negative electrode materials, and reduce system weight, which is conducive to improving energy density.

[0105] In the present application, unless otherwise specified, “solid electrolyte” refers to an electrolyte material or electrolyte substance that exists in a solid state during the storage and preparation of solid-state batteries and components constituting solid-state batteries, and during the working process of solid-state batteries. It can be understood that the solid electrolyte exists in a solid state at room temperature, including but not limited to.

[0106] In the present application, unless otherwise specified, the electrode layer can be a positive electrode layer or a negative electrode layer, and the electrode layer comprises an electrode active material. The electrode active material can be a positive electrode active material or a negative electrode active material. The electrode active material can be in the form of a particle itself or can be contained in an electrode active particle. The electrode active particle can be a positive electrode active particle or a negative electrode active particle. The “electrode active material” in the electrode layer refers to a material capable of reversibly intercalating and deintercalating active ions. Unless otherwise specified, the “negative electrode active material” refers to a material capable of reversibly intercalating and deintercalating active ions used in the negative electrode layer; the “positive electrode active material” refers to a material capable of reversibly deintercalating and intercalating active ions used in the positive electrode layer. During charging of the solid-state battery, active ions are deintercalated from the positive electrode, intercalate the negative electrode through the solid electrolyte layer; and during discharging of the solid-state battery, active ions are deintercalated from the negative electrode and intercalate the positive electrode. The active ion is not particularly limited, and non-limitingly, the active ion can be a lithium ion, in which case a lithium ion solid-state battery corresponds.

[0107] In the present application, the “electrode active particle” refers to a particle containing an electrode active material.

[0108] In the present application, “electrode active material”, “electrode active substance”, “active material” and “active substance” have the same meaning and can be used interchangeably; “positive electrode active material” and “positive electrode active substance” have the same meaning and can be used interchangeably; “negative electrode active material” and “negative electrode active substance” have the same meaning and can be used interchangeably. “Positive electrode active material” and “positive electrode active substance” have the same meaning and can be used interchangeably; “negative electrode active material” and “negative electrode active substance” have the same meaning and can be used interchangeably.

[0109] In the present application, unless otherwise specified, the “electrode active material layer” comprises 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, and according to the detailed circumstances, the electrode active material layer can refer to the positive electrode active material layer or the negative electrode active material layer. It can be understood that the positive electrode active material layer contains a positive electrode active material, and the negative electrode active material layer contains a negative electrode active material. In the present application, the “electrode active material layer” can also be abbreviated as “active material layer”.

[0110] In the present application, unless otherwise specified, the positive electrode layer comprises at least a positive electrode active material layer.

[0111] In the present application, unless otherwise specified, the positive electrode active material layer comprises at least positive electrode active particles, and usually further comprises positive electrode electrolyte particles.

[0112] In the present application, unless otherwise specified, the “positive electrode active particle” refers to a particle containing a positive electrode active material, which has the ability to reversibly deintercalate and intercalate active ions.

[0113] In the present application, unless otherwise specified, "positive electrode electrolyte particles" and "positive electrode solid electrolyte" have the same meaning and can be used interchangeably, referring to a solid electrolyte that can be used in a positive electrode film or a positive electrode layer. The positive electrode electrolyte particles can enhance the ion conduction ability of the positive electrode film or the positive electrode layer, reduce the interface impedance, and promote the charge transfer efficiency of the positive electrode active material to the outside and the full release of its capacity.

[0114] In the present application, unless otherwise specified, the negative electrode layer at least includes a negative electrode active material layer.

[0115] In the present application, unless otherwise specified, the negative electrode active material layer at least includes negative electrode active particles and can or can not include negative electrode electrolyte particles.

[0116] In the present application, unless otherwise specified, "negative electrode active particles" refer to particles containing negative electrode active materials, which have the ability to reversibly intercalate and deintercalate active ions.

[0117] In the present application, unless otherwise specified, "negative electrode electrolyte particles" and "negative electrode solid electrolyte" have the same meaning and can be used interchangeably, referring to a solid electrolyte that can be used in a negative electrode film or a negative electrode layer. The negative electrode electrolyte particles can enhance the ion conduction ability of the negative electrode film or the negative electrode layer, reduce the interface impedance, and promote the charge transfer efficiency of the negative electrode active material to the outside and the full release of its capacity.

[0118] In a solid-state battery, interface contact and interface stability are one of the pain points that limit its performance. Poor interface contact can affect the cycle performance of the battery. Due to the "solid-solid contact" characteristics in the solid-state battery, the contact between particles in the electrode layer includes a large number of point contacts, which cannot completely wet the electrode active material like the electrolyte in the liquid battery. This causes insufficient ion transmission at the interface in the electrode layer, which in turn leads to suboptimal performance of the solid-state battery. By doping solid electrolyte materials into the electrode layer, the ion conduction ability of the electrode layer can be theoretically enhanced, the charge transfer efficiency of the electrode active material to the outside and the full release of its capacity can be promoted, and the impedance can be reduced. Among the many solid electrolyte materials, sulfide solid electrolytes have ultra-high ion conductivity (about 10 -3 ~ 10 -2 S / cm) and excellent mechanical properties, such as good flexibility, making them have excellent ion conduction ability and good deformation ability, and are the most practical and industrialized solid electrolyte material.

[0119] For sulfide solid electrolytes of argyrodite type containing Li element, P element, S element and Cl element, a precursor raw material including Li2S, P2S5 and LiCl is usually used for sintering, and sulfur (S) loss usually occurs during sintering, which easily leads to the presence of impurities such as LiCl in the sintered product. The presence of impurities hinders ion transmission of the sulfide solid electrolyte of argyrodite type, resulting in an unsatisfactory ionic conductivity of the solid electrolyte material.

[0120] When there is an excess of Cl element in the sulfide solid electrolyte of argyrodite type, the S content decreases more obviously with the S loss during sintering, and the content of impurities such as LiCl is higher, which seriously hinders ion transmission, resulting in a significant decrease in the ionic conductivity of the solid electrolyte material.

[0121] According to various embodiments and various examples of the present application, the present application provides a sulfide solid electrolyte and a preparation method thereof, a solid electrolyte film, an electrode sheet, a solid-state battery and an electric device, and can also provide a positive electrode film, a negative electrode film and a secondary battery. The sulfide solid electrolyte has a high ionic conductivity, which can effectively improve the rate performance of the secondary battery or the solid-state battery.

[0122] In a first aspect of the present application, a sulfide solid electrolyte is provided, which includes an argyrodite type crystal phase.

[0123] In some embodiments, the argyrodite type crystal phase includes Li element, P element, S element, M element and T element; wherein the M element is selected from one or both of Se element and Te element, and the T element is selected from one or both of Cl element and Br element.

[0124] In some embodiments, in the argyrodite type crystal phase, the atomic number ratio of the T element to the P element is denoted as 1+x, and x>0.

[0125] In some embodiments, in the argyrodite type crystal phase, the atomic number ratio of the M element to the P element is denoted as y, and y>0.

[0126] In some embodiments, a sulfide solid electrolyte is provided, which includes an argyrodite type crystal phase;

[0127] The argyrodite type crystal phase includes Li element, P element, S element, M element and T element; wherein the M element is selected from one or both of Se element and Te element, and the T element is selected from one or both of Cl element and Br element;

[0128] In the argyrodite type crystal phase, the atomic number ratio of the T element to the P element is denoted as 1+x, and x>0;

[0129] In the argyrodite-type crystal phase, the atomic ratio of the M element to the P element is y, and y > 0.

[0130] In the present application, unless otherwise specified, "sulfide electrolyte" and "sulfide solid electrolyte" have the same meaning and can be used interchangeably, and refer to a solid electrolyte in the form of a sulfide, and the sulfide electrolyte includes a sulfur (S) element in the form of a sulfide. The "sulfide electrolyte" referred to in the embodiments or examples of the present application can be in any one of a solid electrolyte layer, a positive electrode layer, and a negative electrode layer, can be included in an electrolyte material of a solid electrolyte layer, can be included in a positive electrode electrolyte particle, and can be included in a negative electrode electrolyte particle.

[0131] In the present application, unless otherwise specified, "argyrodite-type crystal phase" refers to a crystal structure that is the same as or similar to that of a sulfide solid electrolyte Li6PS5Cl, and belongs to a cubic system, and the argyrodite-type crystal phase corresponds to an argyrodite-type sulfide solid electrolyte. The "argyrodite-type sulfide solid electrolyte" refers to a sulfide solid electrolyte having a crystal structure that is the same as or similar to that of a sulfide solid electrolyte Li6PS5Cl.

[0132] In the sulfide solid electrolyte provided in the present application, in the crystal structure of the argyrodite-type crystal phase, the T element is in excess ((1+x) > 1, that is, x > 0), and the M element that can compensate for the loss of S is introduced.

[0133] In the present application, unless otherwise specified, "atomic ratio" refers to the ratio of the number of specified elements or atoms, and can be measured in moles, in which case it corresponds to "atomic molar ratio".

[0134] In the present application, unless otherwise specified, whether the sulfide solid electrolyte includes argyrodite-type crystal phase can be determined according to X-ray diffraction (XRD) pattern. In the present application, unless otherwise specified, the X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα ray with powder sample. Generally, the 2θ(°) scanning range includes at least 10°-50° (the scanning range can include 10°-80°), and the 2θ(°) scanning speed can be 0.02° / second. In some embodiments, the XRD testing instrument and parameters are as follows: Bruker-D8 advance, using Cu target Kα1 ray, wavelength λ is 0.15406 nm, X-ray tube is controlled at 40 kV and 40 mA, 2θ(°) scanning range is 10°-80°, and 2θ(°) scanning speed is 0.02° / second. Those skilled in the art can confirm whether the sulfide solid electrolyte to be tested includes argyrodite-type crystal phase according to the comparison analysis with the XRD standard spectrum of Li6PS5Cl. In some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte has peaks near 14.6°, 17.4°, 20.2°, 20.5°, 24.0°, 26.9°, 29.5°, 32.6°, 36.5°, 41.5° and 47.3° of 2θ(°) diffraction angle in the following group. Due to the differences in measurement instruments and measurement conditions and other measurement factors, the position of a certain peak or some peaks in the actually obtained X-ray diffraction pattern can be slightly shifted (for example, ±δ°), but it can be understood that for those skilled in the art, whether the X-ray diffraction pattern including slightly different characteristic peaks constitutes argyrodite-type crystal phase in essence can be identified as a whole. Unless otherwise specified, "±δ°" only represents the error of the peak value in the diffraction angle position, and is irrelevant to the peak shape and peak width of the peak. Numerically, regarding the aforementioned peak position shift ±δ°, δ can be 0.4, 0.3, 0.2, 0.1 and the like according to the measurement conditions, for example, in some embodiments, δ=0.2.

[0135] In the present application, unless otherwise specified, the types of elements and the atomic number ratio of each element in the sulfide solid electrolyte can be determined according to elemental analysis methods such as inductively coupled plasma spectrometer (ICP method), so as to determine the chemical formula.

[0136] The sulfide solid electrolyte provided in the first aspect of the present application is a argyrodite-type sulfide solid electrolyte comprising an argyrodite-type crystal phase containing Li element, P element, S element, and T element (T element is one or both of Cl element and Br element); in the case where the atomic number ratio of T element to P element (1+x) is greater than 1 (x>0 at this time), by introducing M element (which can be selected from one or both of Se element and Te element), on the one hand, the excess T element can generate more lithium vacancies; on the other hand, the smaller Coulombic binding force of T element to lithium ion can facilitate the migration of lithium ion, which is conducive to promoting the diffusion of lithium ion and improving the ionic conductivity of the solid electrolyte; on the other hand, M element can compensate for the loss of sulfur (S) of sulfide raw materials during sintering, which can inhibit the generation of LiT and other impurities, and is also conducive to improving the ionic conductivity of the solid electrolyte; on the other hand, the ionic radius of M element is larger than that of S element, which can widen the ion transmission channel in the crystal structure, and the aforementioned multiple synergistic effects can significantly improve the ionic conductivity of the argyrodite-type sulfide solid electrolyte.

[0137] When the sulfide solid electrolyte is used as a solid electrolyte material in a secondary battery or a solid-state battery, it can be used as a solid electrolyte material in one or more structural layers of a solid electrolyte layer, a positive electrode layer, and a negative electrode layer, which can effectively reduce the resistance of the solid-state battery and improve the rate performance of the secondary battery or the solid-state battery, and can make the secondary battery or the solid-state battery have better electrochemical performance at high rate.

[0138] When the sulfide solid electrolyte is used as a positive electrode electrolyte particle in the positive electrode layer, it can also promote the capacity of the positive electrode active material in the positive electrode layer.

[0139] When the sulfide solid electrolyte is used as a positive electrode electrolyte particle in the positive electrode layer, it can also promote the capacity of the positive electrode active material in the positive electrode layer.

[0140] In some embodiments, in the argyrodite-type crystal phase, 0

[0141] By controlling x within the aforementioned range, the T element can be controlled within a more optimal range, which is conducive to better improving the ionic conductivity of the sulfide solid electrolyte, and can also simultaneously control the content of impurities at a lower proportion.

[0142] In some embodiments, in the argyrodite-type crystal phase, 0 < y ≤ 0.1. Without limitation, y can also be any of the following values, greater than 0 and less than or equal to any of the following values, or selected from the interval between any two of the following values: 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc.

[0143] By controlling y within the aforementioned range, the M element can be controlled within a more optimal range, which is more conducive to inhibiting impurity phases and improving the ionic conductivity of the sulfide solid electrolyte.

[0144] In some embodiments, in the argyrodite-type crystal phase, the atomic number ratio of the Li element, the P element, the S element, the M element, and the T element is (6-x):1:(5-x-y):y:(1+x), where 0 < x ≤ 0.8 and 0 < y ≤ 0.1. x and y can be combined in any suitable manner. x and y can also refer to any suitable value or range in the context.

[0145] In some embodiments, the argyrodite-type crystal phase has the chemical formula Li 6-x PS 5-x-y M y T 1+x .

[0146] When the argyrodite-type crystal phase has the aforementioned chemical formula, it is more conducive to better inhibiting impurity phases and better improving the ionic conductivity of the sulfide solid electrolyte.

[0147] In some embodiments, the argyrodite-type crystal phase has the chemical formula Li 6-x PS 5-x-y Se y Cl 1+x .

[0148] When the M element includes the Se element and the T element includes the Cl element, the sulfide solid electrolyte has more optimal ionic conductivity.

[0149] In some embodiments, the argyrodite-type crystal phase satisfies one or more of the following characteristics (any numerical parameter in the following characteristics can also be selected from any suitable value or range in the context):

[0150] In the argyrodite-type crystal phase, 0 < x ≤ 0.8, optionally, 0.05 ≤ x ≤ 0.8; further optionally, 0.1 ≤ x ≤ 0.8; still further optionally, 0.3 ≤ x ≤ 0.8.

[0151] In the argyrodite-type crystal phase, 0 < y ≤ 0.1; optionally, 0.02 ≤ y ≤ 0.1; further optionally, 0.02 ≤ y ≤ 0.09.

[0152] In some embodiments, 0.3≤x≤0.8, 0.02≤y≤0.09.

[0153] By controlling one or both of x and y within the aforementioned ranges, the T element and the M element can be adjusted to have more suitable contents, which is conducive to better improving the ionic conductivity of the sulfide solid electrolyte. Among them, by controlling y within the aforementioned range, the M element can be controlled within a more optimal range, which is more conducive to suppressing impurities and improving the ionic conductivity of the sulfide solid electrolyte.

[0154] In the present application, in the argyrodite-type crystal phase, the atomic ratio of the S element to the P element can be denoted as 5-x-y.

[0155] In some embodiments, 4.1≤(5-x-y)<5.0. Without limitation, 5-x-y can also be any of the following values, greater than or equal to any of the following values and less than 5.0, greater than or equal to any of the following values and less than 4.7, or selected from the interval consisting of any two of the following values: 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 4.95, etc.

[0156] In some of the embodiments, 4.1<(5-x-y)<4.7.

[0157] When the atomic ratio of the S element to the P element (5-x-y) is controlled within the aforementioned range, by controlling the contents of x and y, it is more conducive to suppressing impurities and improving the ionic conductivity of the sulfide solid electrolyte.

[0158] In some embodiments, in the argyrodite-type crystal phase, the T element includes Cl element.

[0159] In some embodiments, in the argyrodite-type crystal phase, the M element includes Se element.

[0160] In some embodiments, in the argyrodite-type crystal phase, the T element includes Cl element; and the M element includes Se element.

[0161] When the M element includes Se element, it is conducive for the sulfide solid electrolyte to have more optimal ionic conductivity.

[0162] When the T element includes Cl element, it is conducive for the sulfide solid electrolyte to have more optimal ionic conductivity.

[0163] In the present application, in the argyrodite-type crystal phase, the atomic ratio of Cl element to Br element can be denoted as R Cl / Br .

[0164] Without limitation, R Cl / Brmay be (0-1):(0-1), may be 1:(0-1), and may be (0-1):1.

[0165] In the present application, in the argyrodite-type crystal phase, the atomic number ratio of Se element and Te element can be denoted as R Se / Te .

[0166] Non-limitingly, R Se / Te may be (0-1):(0-1), may be 1:(0-1), and may be (0-1):1.

[0167] Regarding any of the above ratios of R Cl / Br and R Se / Te , the value in the range of 0-1 can be any of the following values, or selected from the interval consisting of any two of the following values: 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.55, 0.6, 0.625, 0.64, 0.65, 0.7, 0.75, 0.8, 0.825, 0.9, 0.95, 1, etc.

[0168] In some embodiments, the argyrodite-type crystal phase satisfies one or both of the following characteristics (any numerical parameter in the following characteristics can also be selected from any suitable value or range in the context):

[0169] In the argyrodite-type crystal phase, the atomic number ratio of Cl element and Br element is greater than or equal to 1;

[0170] In the argyrodite-type crystal phase, the atomic number ratio of Se element and Te element is greater than or equal to 1.

[0171] By setting one or both of the characteristics of "the atomic number ratio of Cl element and Br element is greater than 1" and "the atomic number ratio of Se element and Te element is greater than 1", it is more conducive to improving the ionic conductivity of the sulfide solid electrolyte.

[0172] In some embodiments, the argyrodite-type crystal phase has any of the following chemical formulas: Li 5.7 PS 4.65 Se 0.05 Cl 1.3 , Li 5.5 PS 4.44 Se 0.06 Cl1Br 0.5 , Li 5.5 PS 4.44 Se 0.05 Te 0.01 Cl1Br 0.5 and Li 5.5 PS 4.44 Se 0.06 Cl 1.5.

[0173] By setting one or more argyrodite-type crystal phases in the sulfide solid electrolyte, the impurity phase can be reduced and the ionic conductivity can be improved.

[0174] In some embodiments, the 2θ(°) diffraction angle in the X-ray diffraction pattern of the sulfide solid electrolyte has characteristic peaks consistent with argyrodite-type crystal phase. For the definition and identification method of "argyrodite-type crystal phase", please refer to the foregoing.

[0175] In some embodiments, the 2θ(°) diffraction angle in the X-ray diffraction pattern of the sulfide solid electrolyte has peaks at 15.5±δ°, 18.1±δ°, 25.6±δ°, 30.1±δ°, 31.4±δ°, 39.8±δ°, 45.1±δ°, 47.9±δ° and 52.5±δ°, wherein δ can be referred to the foregoing; optionally, δ is 0.2 or 0.1.

[0176] In some embodiments, the 2θ(°) diffraction angle in the X-ray diffraction pattern of the sulfide solid electrolyte has peaks at 15.5±0.2°, 18.1±0.2°, 25.6±0.2°, 30.1±0.2°, 31.4±0.2°, 39.8±0.2°, 45.1±0.2°, 47.9±0.2° and 52.5±0.2°.

[0177] According to the comparison between the intensity of the main diffraction peak (the strongest diffraction peak) of the argyrodite-type crystal phase and the intensity of the diffraction peak of the impurity phase in the XRD pattern, the relative content of the impurity phase can be determined.

[0178] In some embodiments, the 2θ(°) diffraction angle in the X-ray diffraction pattern of the sulfide solid electrolyte has no diffraction peak at 34.9±0.2°, 29.2±0.2° and 33.9±0.2°, at this time, the content of the impurity phase is extremely small. Among them, 34.9° corresponds to the 2θ diffraction peak of LiCl.

[0179] In some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte has no LiT impurity phase peak.

[0180] In some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte has no obvious LiT impurity phase diffraction peak.

[0181] In some embodiments, the mass fraction of the argyrodite-type crystal phase in the sulfide solid electrolyte can be greater than 85wt%, and can be greater than or equal to any one of the following percentages, or greater than or equal to any one of the following percentages, or selected from the range consisting of any one of the following percentages and 100wt%, or selected from the range consisting of any two of the following percentages: 90wt%, 92wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, and the like.

[0182] In some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα rays, and in some of the embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα1 rays.

[0183] In some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte is obtained by powder X-ray diffraction testing.

[0184] In some embodiments, the sulfide solid electrolyte satisfies at least one of the following characteristics:

[0185] The 2θ (°) diffraction angle in the X-ray diffraction pattern of the sulfide solid electrolyte has peaks at 15.5±δ°, 18.1±δ°, 25.6±δ°, 30.1±δ°, 31.4±δ°, 39.8±δ°, 45.1±δ°, 47.9±δ°, and 52.5±δ°, wherein δ is 0.2 or 0.1;

[0186] There is no LiT impurity phase peak in the X-ray diffraction pattern of the sulfide solid electrolyte;

[0187] The 2θ (°) diffraction angle in the X-ray diffraction pattern of the sulfide solid electrolyte has no diffraction peaks at 34.9±0.2°, 29.2±0.2°, and 33.9±0.2°;

[0188] The X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα rays;

[0189] The X-ray diffraction pattern of the sulfide solid electrolyte is obtained by powder X-ray diffraction testing.

[0190] The chemical composition and impurity phase in the sulfide solid electrolyte can be confirmed by X-ray diffraction (XRD) detection.

[0191] In the second aspect of the present application, a preparation method of a sulfide solid electrolyte is provided, which can be used to prepare the sulfide solid electrolyte described in the first aspect of the present application.

[0192] In some embodiments, the preparation method of the sulfide solid electrolyte comprises the following steps:

[0193] S100: providing a precursor mixture including Li2S, P2S5, optional elemental sulfur, elemental M, and LiT according to stoichiometric ratios of raw materials required; wherein the elemental M is selected from one or both of elemental Se and elemental Te, T is a halogen, and LiT is selected from one or both of LiCl and LiBr;

[0194] S200: sintering the precursor mixture in an inert atmosphere to prepare a sulfide solid electrolyte including a kesterite-type crystal phase;

[0195] In the kesterite-type crystal phase, an atomic number ratio of the element T to the element P is denoted as 1+x, and an atomic number ratio of the element M to the element P is denoted as y, and in some embodiments, the kesterite-type crystal phase satisfies x>0 and y>0.

[0196] In the present application, unless otherwise specified, “providing according to stoichiometric ratios of raw materials required” in step S100 refers to providing according to stoichiometric ratios of raw materials required to obtain a target chemical formula. In the case where the target chemical formula is determined, a person skilled in the art can select appropriate precursor raw materials and appropriate stoichiometric ratios of raw materials.

[0197] In the present application, unless otherwise specified, “elemental M” is elemental Se, elemental Te, or a combination of elemental Se and elemental Te.

[0198] In some embodiments, the elemental M includes elemental Se, and can further be elemental Se.

[0199] In some embodiments, the elemental M includes elemental Te, and can further be elemental Te.

[0200] In some embodiments, in the step of sintering the precursor mixture in an inert atmosphere, the sintering temperature can be 450°C to 530°C.

[0201] Without limitation, in step S200, the sintering temperature can be 450°C to 530°C, and can also be any two of the following temperatures or a range selected from any two of the following temperatures: 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, and the like.

[0202] Without limitation, in step S200, the inert atmosphere can be an argon atmosphere.

[0203] In some embodiments, the sulfide solid electrolyte prepared by the preparation method of the second aspect is the sulfide solid electrolyte described in the first aspect of the present application.

[0204] In a third aspect of the present application, a solid electrolyte membrane is provided, which comprises at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application.

[0205] Without limitation, the solid electrolyte membrane can be a stand-alone solid electrolyte membrane, which is further used to assemble a solid-state battery; the solid electrolyte membrane can also be a solid electrolyte membrane layer present in a composite structure.

[0206] The solid electrolyte membrane can be prepared by a conventional method in the field of solid-state batteries, such as pressing the solid electrolyte material into a membrane.

[0207] In some embodiments, the solid electrolyte membrane is a full solid-state electrolyte membrane.

[0208] In the present application, unless otherwise specified, the “full solid-state electrolyte membrane” refers to a solid electrolyte membrane whose constituent materials are all in solid state.

[0209] In another aspect of the present application, a solid electrolyte membrane is provided, which comprises at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application.

[0210] In another aspect of the present application, a positive electrode membrane is provided, which comprises a positive electrode active material layer, the positive electrode active material layer comprising at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application.

[0211] Without limitation, the positive electrode membrane can be a stand-alone positive electrode membrane or a positive electrode tab, which is further used to assemble a solid-state battery; the positive electrode membrane can also be a positive electrode membrane layer present in a multi-layer composite structure, for example, the constituent materials of the positive electrode membrane layer can be pressed into a membrane on the surface of a solid electrolyte layer. As a non-limiting example, the positive electrode membrane can be a positive electrode layer or a part of a positive electrode layer of a solid-state battery.

[0212] In some embodiments, the positive electrode membrane is a full solid-state positive electrode membrane.

[0213] In the present application, unless otherwise specified, the “full solid-state positive electrode membrane” refers to a positive electrode membrane whose constituent materials are all in solid state.

[0214] In another aspect of the present application, a positive electrode membrane is provided, which comprises a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector, the positive electrode active material layer comprising at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application.

[0215] In a further aspect of the present application, a negative electrode film is provided, which comprises a negative electrode active material layer, the negative electrode active material layer comprising at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application.

[0216] Without limitation, the negative electrode film can be a separate negative electrode film or negative electrode tab, which is further used for assembling 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 material 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 part of a negative electrode layer of a solid-state battery.

[0217] In some embodiments, the negative electrode film is a full solid-state negative electrode film.

[0218] In the present application, unless otherwise specified, the "full solid-state negative electrode film" refers to a negative electrode film whose constituent materials are all in a solid state.

[0219] In a further aspect of the present application, a negative electrode tab is provided, which 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, the negative electrode active material layer comprising at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application.

[0220] For the solid electrolyte film, the positive electrode film or the negative electrode film provided with the aforementioned sulfide solid electrolyte, the resistance can be effectively reduced, the corresponding secondary battery or solid-state battery can be endowed with better rate performance, and the secondary battery or solid-state battery can have better electrochemical performance at high rate.

[0221] When the sulfide solid electrolyte is used as the positive electrode electrolyte particles in the positive electrode layer, the capacity of the positive electrode active material in the positive electrode layer can also be promoted.

[0222] When the sulfide solid electrolyte is used as the positive electrode electrolyte particles in the negative electrode layer, the capacity of the positive electrode active material in the negative electrode layer can also be promoted.

[0223] In a fourth aspect of the present application, an electrode tab is provided, which comprises an electrode active material layer, the electrode active material layer comprising an electrode active material, the electrode active material layer further comprising at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application.

[0224] In some embodiments, the electrode tab is a positive electrode tab, the electrode active material layer is referred to as a positive electrode active material layer, and the electrode active material is referred to as a positive electrode active material;

[0225] Alternatively, the electrode tab is a negative electrode tab, and the electrode active material layer is referred to as a negative electrode active material layer, and the electrode active substance is referred to as a negative electrode active substance.

[0226] In the present application, unless otherwise specified, the electrode tab includes the electrode active material layer. As previously described, the electrode active material layer includes the electrode active substance. In the electrode tab, the electrode active substance can itself constitute a particulate substance or can be contained in an electrode active particle. Unless otherwise specified, the electrode active material layer in the electrode tab provided in this aspect further includes the sulfide solid electrolyte, and further, the electrode active material layer includes at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application.

[0227] In some embodiments, the electrode active material layer includes the electrode active particle, and the electrode active material layer further includes at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application. The electrode tab can be a positive electrode tab, and the electrode active particle is a positive electrode active particle, and in this case, a positive electrode tab is provided, which includes a positive electrode active material layer including the positive electrode active particle and the aforementioned sulfide solid electrolyte. The electrode tab can also be a negative electrode tab, and the electrode active particle is a negative electrode active particle, and in this case, a negative electrode tab is provided, which includes a negative electrode active material layer including the negative electrode active particle and the aforementioned sulfide solid electrolyte.

[0228] For the electrode tab provided with the aforementioned sulfide solid electrolyte, the internal resistance of the tab can be reduced, the capacity of the active substance in the tab can be promoted, and the corresponding secondary battery or solid-state battery can be provided with better rate performance.

[0229] The electrode tab can be a positive electrode tab or a negative electrode tab.

[0230] In still another aspect of the present application, a secondary battery is provided, which includes at least one of the sulfide solid electrolyte described in the first aspect of the present application, the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application, the solid electrolyte film described in the third aspect of the present application, the aforementioned positive electrode film, the aforementioned negative electrode film, and the electrode tab described in the fourth aspect of the present application.

[0231] In the present application, unless otherwise specified, the "secondary battery" provided in the present application as previously described includes a positive electrode tab, a negative electrode tab, and a solid electrolyte layer between the positive electrode tab and the negative electrode tab.

[0232] In the present application, unless otherwise specified, the "positive electrode tab" includes a positive electrode active material layer. In some embodiments, the positive electrode tab in the secondary battery is the aforementioned positive electrode film.

[0233] In the present application, unless otherwise specified, the "negative electrode sheet" includes the negative active material layer. In some embodiments, the negative electrode sheet in the secondary battery is the aforementioned negative electrode film.

[0234] In the present application, unless otherwise specified, the "solid electrolyte layer" includes the solid electrolyte. In some embodiments, the solid electrolyte layer is a solid electrolyte film layer composed of the solid electrolyte film described in the third aspect of the present application.

[0235] When the secondary battery is charged, active ions are extracted from the positive electrode and inserted into the negative electrode through the solid electrolyte layer; and when the secondary battery is discharged, active ions are extracted from the negative electrode and inserted into the positive electrode. The active ions are not particularly limited, and non-limitingly, the active ions can be lithium ions, in which case it is a lithium ion secondary battery.

[0236] In the fifth aspect of the present application, there is provided a solid-state battery comprising at least one of the sulfide solid electrolyte described in the first aspect of the present application, the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application, the solid electrolyte film described in the third aspect of the present application, the aforementioned positive electrode film, the aforementioned negative electrode film, and the electrode sheet described in the fourth aspect of the present application.

[0237] In some embodiments, the solid-state battery comprises at least one of the sulfide solid electrolyte described in the first aspect of the present application, the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application, the solid electrolyte film described in the third aspect of the present application, and the electrode sheet described in the fourth aspect of the present application.

[0238] In some embodiments, the positive electrode layer in the solid-state battery comprises the aforementioned positive electrode film, and further can be the aforementioned positive electrode film.

[0239] In some embodiments, the negative electrode layer in the solid-state battery comprises the aforementioned negative electrode film, and further can be the aforementioned negative electrode film.

[0240] In some embodiments, the solid electrolyte layer in the solid-state battery comprises the solid electrolyte film described in the third aspect of the present application, and further can be the solid electrolyte film described in the third aspect of the present application.

[0241] In some embodiments, the solid-state battery is a sulfide all-solid-state battery.

[0242] The "solid-state battery" provided in the fifth aspect of the present application comprises at least one of the sulfide solid electrolyte described in the first aspect of the present application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of the present application, and thus it is a sulfide all-solid-state battery.

[0243] In the present application, unless otherwise specified, "sulfide solid-state battery" refers to a solid-state battery in which the electrolyte involved in the battery includes a sulfide solid electrolyte. The sulfide solid electrolyte can be located in at least one of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer of the sulfide solid-state battery. The sulfide solid-state battery can further be a full solid-state battery.

[0244] In the present application, unless otherwise specified, "full solid-state battery" refers to a solid-state battery in which the electrolyte in the battery is a solid electrolyte. At this time, the positive electrode layer, the negative electrode layer, and the electrolyte part all use solid materials, and no liquid electrolyte is provided in the battery, so it can be called a "full solid-state battery".

[0245] In the present application, unless otherwise specified, "solid-state battery" in any embodiment or example can be, but is not limited to, a sulfide full solid-state battery. Unless otherwise specified, "sulfide full solid-state battery" refers to a full solid-state battery in which the electrolyte involved in the battery includes a sulfide solid electrolyte. Among them, the sulfide solid electrolyte can be located in at least one of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer of the sulfide full solid-state battery.

[0246] The types of solid electrolytes present in different film layers of the secondary battery or the solid-state battery can be the same or different. For example, the positive electrode electrolyte particles, the negative electrode electrolyte particles, and the solid electrolyte in the solid electrolyte layer can be the same or different.

[0247] In the secondary battery or the solid-state battery provided in the present application, at least one of the positive electrode electrolyte particles, the negative electrode electrolyte particles, and the solid electrolyte in the solid electrolyte layer comprises the sulfide solid electrolyte described in the first aspect of the present application.

[0248] For the secondary battery or the solid-state battery provided with the aforementioned sulfide solid electrolyte, the sulfide solid electrolyte can be provided in one or more of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer.

[0249] As non-limiting examples, the positive electrode electrolyte particles, the negative electrode electrolyte particles, and the solid electrolyte in the solid electrolyte layer can each independently include a solid electrolyte material known in the art that can be used in a solid-state battery, for example, can each independently include one or more of the following materials: one or more of a sulfide-based solid electrolyte, a halide-based solid electrolyte, an oxide-based solid electrolyte, a polymer-based solid electrolyte, and the like.

[0250] In a sixth aspect of the present application, a power device is provided, which comprises at least one of the sulfide solid electrolyte of the first aspect of the present application, the sulfide solid electrolyte prepared by the preparation method of the second aspect of the present application, the solid electrolyte film of the third aspect of the present application, the positive electrode film, the negative electrode film, the electrode tab of the fourth aspect of the present application, the secondary battery and the solid-state battery of the fifth aspect of the present application.

[0251] In some embodiments, the power device comprises at least one of the sulfide solid electrolyte of the first aspect of the present application, the sulfide solid electrolyte prepared by the preparation method of the second aspect of the present application, the solid electrolyte film of the third aspect of the present application, the electrode tab of the fourth aspect of the present application and the solid-state battery of the fifth aspect of the present application.

[0252] Some descriptions about the solid electrolyte layer are as follows.

[0253] The solid electrolyte layer plays a role of conducting ions between the positive electrode layer and the negative electrode layer, and also plays a role of isolating the positive electrode layer from the negative electrode layer to prevent short circuit of the positive electrode and the negative electrode.

[0254] It can be understood that the solid electrolyte layer comprises a solid electrolyte. The solid electrolyte in the solid electrolyte layer can adopt a solid electrolyte material known in the art and applicable to a solid-state battery.

[0255] In some embodiments, the solid electrolyte layer comprises the sulfide solid electrolyte of the first aspect of the present application.

[0256] In some embodiments, the solid electrolyte layer can be pressed from a solid electrolyte material into a solid electrolyte film, which can be a solid electrolyte film sheet or a solid electrolyte film layer.

[0257] In some embodiments, the thickness of the solid electrolyte layer can be 0.1 μm to 1000 μm, optionally 10 μm to 100 μm, 100 μm to 800 μm, 500 μm to 800 μm, etc.

[0258] Some descriptions about the positive electrode film and the positive electrode layer are as follows.

[0259] In the present application, unless otherwise specified, the "positive electrode film" refers to a film capable of being used as a positive electrode of a solid-state battery, which at least comprises a positive electrode active material layer, and usually further comprises a positive electrode current collector.

[0260] The positive electrode layer can be provided by a positive electrode tab or a positive electrode film sheet applicable to a solid-state battery in the art, or the constituent materials of the positive electrode layer can be directly pressed into a positive electrode film layer on one side surface of the solid electrolyte layer. The positive electrode film sheet can be compounded with other films suitable for a positive electrode to form a positive electrode tab or a positive electrode layer.

[0261] The positive electrode layer can be prepared by a dry method or a wet method. For example, a dry method can be used to press a positive electrode film, which can be a positive electrode sheet or a positive electrode layer. For another example, a wet method can be used to coat a positive electrode film, which can be a positive electrode layer.

[0262] In some embodiments, the positive electrode film comprises a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, and the positive electrode active material layer is as defined above.

[0263] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, an aluminum foil can be used. In the positive electrode current collector, the composite current collector can comprise 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 can be obtained by forming a metal material on a polymer material base material. In the positive electrode current collector, non-limiting examples of the metal material can include one or more of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, a silver alloy, and the like. In the positive electrode current collector, non-limiting examples of the polymer material base material can include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), and the like.

[0264] Non-limitingly, in the positive electrode film or the positive electrode layer, the thickness of the positive electrode active material layer is 30 μm to 400 μm, which can be optionally 60 μm to 130 μm, and can also be any one of the following thicknesses or a range selected from any two of the following thicknesses: 30 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 180 μm, 200 μm, and the like.

[0265] In the present application, unless otherwise specified, the "thickness of the positive electrode active material layer" refers to the total thickness in the positive electrode film or the positive electrode layer. When the positive electrode active material layer is disposed 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 the two sides.

[0266] As a non-limiting example, the positive electrode current collector has two surfaces facing away from each other in the thickness direction thereof, and the positive electrode active material layer is disposed on any one or both of the two surfaces of the positive electrode current collector facing away from each other.

[0267] The positive electrode film and the positive electrode layer each comprise a positive electrode active material layer, and the positive electrode active material layer comprises positive electrode active particles containing a positive electrode active material.

[0268] Non-limitingly, the weight percentage of the positive electrode active particles or positive electrode active material in the positive electrode active material layer can be ≥ 70 wt%, further can be ≥ 80 wt%, more further can be ≥ 90 wt%, and can also be any one of the following weight percentages or a range consisting of any two of the following weight percentages: 70 wt%, 75 wt%, 80 wt%, 82 wt%, 84 wt%, 85 wt%, 86 wt%, 88 wt%, 90 wt%, 92 wt%, 94 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 99 wt%, etc.

[0269] In some embodiments, the positive electrode active material layer comprises positive electrode electrolyte particles. Non-limitingly, the weight percentage of the positive electrode electrolyte particles in the positive electrode active material layer can be 0.1 wt% to 30 wt%, and can be optionally 5 wt% to 20 wt%, and the weight percentage of the positive electrode electrolyte particles in the positive electrode active material layer can also be any one of the following weight percentages or a range consisting of any two of the following weight percentages: 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 12 wt%, 14 wt%, 15 wt%, 16 wt%, 18 wt%, 20 wt%, 22 wt%, 24 wt%, 25 wt%, 26 wt%, 28 wt%, 30 wt%, etc.

[0270] In some embodiments, the positive electrode active material layer comprises positive electrode active particles and positive electrode electrolyte particles.

[0271] In some embodiments, the positive electrode active material in the positive electrode active particles may be a battery-use positive electrode active material known in the art. As non-limiting examples, the positive electrode active material may include one or more of the following materials: olivine-structured lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials; other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used singly or in combination. Examples of lithium transition metal oxides 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 their modified compounds. Non-limiting examples of olivine-structured lithium-containing phosphates 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 iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Non-limiting examples of lithium cobalt oxides may include LiCoO2; non-limiting examples of lithium nickel oxides may include LiNiO2; non-limiting examples of lithium manganese oxides may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides 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. An example of lithium iron phosphate is LiFePO4 (also referred to as LFP). An example of lithium manganese phosphate is LiMnPO4.

[0272] In the case of solid-state batteries with active ions including lithium ions, it is understandable that the solid-state batteries will be accompanied by lithium (Li) deintercalation and consumption during charging and discharging, and the content of Li in the positive electrode layer is different when the battery is discharged to different states. In the exemplary description of the positive electrode active material in this application, unless otherwise stated, the content of Li can be the initial state of the material or the non-initial state after charging and discharging cycle. When the positive electrode active material is applied to the positive electrode layer in the solid-state battery system, the content of Li in the positive electrode active material contained in the positive electrode layer will usually change after charging and discharging cycle. The content of Li can be measured by atomic molar content, but is not limited thereto. As for "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 proper modification of the listed positive electrode active materials are also within the scope of positive electrode active materials, and the foregoing proper modification refers to acceptable modification methods for positive electrode active materials, and non-limiting examples include coating modification. In the exemplary description of the positive electrode active material in this application, the content of oxygen (O) is usually the theoretical state value, and the release of oxygen from the lattice will cause the atomic molar content of oxygen to change, and the actual content of O will fluctuate. The content of O can be measured by atomic molar content, but is not limited thereto.

[0273] In some embodiments, the positive electrode active material layer includes a conductive agent (which can be referred to as a positive electrode conductive agent). As a non-limiting example, the positive electrode conductive agent can be a carbon conductive agent. Non-limitingly, the carbon conductive agent can include one or more of super P, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the positive electrode conductive agent can include, but is not limited to, one or more of SP, KS-6, acetylene black, branched ketjen black ECP, SFG-6, vapor grown carbon fiber VGCF, carbon nanotubes (CNTs), and graphene. Non-limitingly, the weight percentage of the positive electrode conductive agent in the positive electrode active material layer can be 0-10 wt%, further can be 0-8 wt%, further can be 0-5 wt%, further can be 0.1 wt%-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 can also be 0.1 wt%-5 wt%, 0.2 wt%-5 wt%, 0.5 wt%-5 wt%, 0.1 wt%-3 wt%, etc.

[0274] In some embodiments, the positive electrode active material layer optionally comprises a binder (may be referred to as a positive electrode binder). As non-limiting examples, the positive electrode binder can comprise one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin. Typically, the weight percentage of the positive electrode binder in the positive electrode active material layer can be 0-10 wt%, further can be 0-8 wt%, further can be 0.1 wt%-5 wt%, further can be 1 wt%-5 wt%, based on the total weight of the positive electrode active material layer.

[0275] Non-limitingly, the positive electrode active material layer can comprise positive electrode active particles, positive electrode electrolyte particles, a positive electrode conductive agent, and a positive electrode binder. The types and contents of the components can be referred to the context of the present application.

[0276] In some embodiments, the positive electrode electrolyte particles comprise the sulfide solid electrolyte described in the first aspect of the present application.

[0277] In some embodiments, the positive electrode film (which can be used as a positive electrode sheet) can be prepared by dry mixing the components described above for preparing the positive electrode film, such as the positive electrode active particles, the positive electrode electrolyte particles, the positive electrode conductive agent, the optional positive electrode binder, and any other components, followed by heating and pressure kneading the mixed material into a dough-like material, hot rolling the dough-like material to form a self-supporting positive electrode sheet, and hot roll-complexing the self-supporting positive electrode sheet with a positive electrode current collector, which can be on at least one side (single side or double sides) of the positive electrode current collector, to obtain the positive electrode film. Non-limitingly, a double planetary mixer can be used for the dry mixing. Non-limitingly, an internal mixer can be used for the heating and pressure kneading. Non-limitingly, the temperature for the hot rolling can be 75-85 °C, further such as 78 °C, 80 °C, 82 °C, etc. The method for assembling the solid-state battery using the positive electrode film can be suitable for industrial batch production. A similar method can be used to prepare a negative electrode film or a negative electrode sheet.

[0278] In some embodiments, the positive electrode film can be prepared by dispersing the above-mentioned components for preparing the positive electrode film, such as the positive electrode active particles, the positive electrode electrolyte particles, the positive electrode conductive agent, the positive electrode binder and any other components, in an organic solvent to form a positive electrode slurry. Further, the positive electrode slurry is coated on at least one side surface of the positive electrode current collector, and after drying, pressing and other processes, the positive electrode film is obtained. The type of the organic solvent in the positive electrode slurry can include one or more of p-xylene, m-xylene, butyl butyrate, heptane and the like, and further can be p-xylene. The surface of the positive electrode current collector coated with the positive electrode slurry can be on a single surface of the positive electrode current collector, or on both surfaces of the positive electrode current collector. The solid content of the positive electrode slurry can be 40wt% to 80wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000mPa·s to 25000mPa·s. When coating the positive electrode slurry, the coating unit area density (single side) by dry weight (excluding solvent) can be 15mg / cm 2 to 35mg / cm 2 . The compaction density of the positive electrode film can be 3.0g / cm 3 to 3.6g / cm 3 , and optionally 3.3g / cm 3 to 3.5g / cm 3 .

[0279] As used herein, "compaction density" has the meaning commonly known in the art as one of the reference indicators of the energy density of a material. In the present application, unless otherwise specified, the compaction density of an electrode layer refers to the ratio of the mass of the electrode active material layer to its volume. The compaction density of a positive electrode layer, positive electrode tab, positive electrode film or positive electrode film refers to the ratio of the mass of the positive electrode active material layer to its volume, and the compaction density of a negative electrode layer, negative electrode tab, negative electrode film or negative electrode film refers to the ratio of the mass of the negative electrode active material layer to its volume.

[0280] Compaction density = coating area density / thickness of the electrode active material layer.

[0281] Coating area density = dry weight of the slurry / area of the electrode active material layer.

[0282] The double-sided thickness of the electrode active material layer corresponds to the sum of the double-sided coating area density, and the single-sided thickness corresponds to the single-sided coating area density; when the electrode active material layers on both sides of the current collector are substantially the same, the compaction density can be calculated as follows: compaction density = single-sided coating area density / single-sided thickness of the electrode active material layer.

[0283] "Single-sided" and "double-sided" of the electrode active material layer are relative to the position distribution of the current collector.

[0284] The following is some description of the negative electrode film and negative electrode layer.

[0285] In the present application, unless otherwise specified, “negative electrode film” refers to a film that can be used as a negative electrode of a solid-state battery, and at least includes a negative electrode active material layer, and can further include a negative electrode current collector.

[0286] The negative electrode layer can be provided by a negative electrode tab or a negative electrode film sheet that is known in the art for use in a solid-state battery, or the constituent materials of the negative electrode layer can be directly pressed into a negative electrode film layer on one side surface of the solid electrolyte layer. The negative electrode film sheet can be combined with other films suitable for a negative electrode to form a negative electrode tab or a negative electrode layer.

[0287] The negative electrode layer can be prepared by a dry method or a wet method. For example, a dry method can be used to press a negative electrode film, which can be a negative electrode film sheet or a negative electrode film layer. For another example, a wet method can be used to coat a negative electrode film, which can be a negative electrode film layer.

[0288] The negative electrode film and the negative electrode layer each include a negative electrode active material layer, and the negative electrode active material layer includes negative electrode active particles containing a negative electrode active substance. Non-limitingly, the negative electrode active material layer can or can not include negative electrode electrolyte particles.

[0289] In some embodiments, the negative electrode active material layer includes negative electrode electrolyte particles, and further, the negative electrode electrolyte particles can include the sulfide solid electrolyte described in the first aspect of the present application.

[0290] Non-limitingly, the weight percentage of the negative electrode active particles or the negative electrode active substance in the negative electrode active material layer can be ≥ 80 wt%, and further can be ≥ 90 wt%.

[0291] In some embodiments, the negative electrode active particles or the negative electrode active substance is a lithium-indium alloy (InLi alloy).

[0292] In some embodiments, the negative electrode layer is an InLi alloy film.

[0293] In some embodiments, the negative electrode active substance can also use a negative electrode active substance known in the art for use in a solid-state battery. As a non-limiting example, the negative electrode active substance can include one or more of the following materials: one or more of elemental silicon, elemental tin, a silicon-carbon negative electrode (i.e., a silicon-carbon composite material), silicon monoxide, graphite, metallic lithium. However, the present application is not limited to these materials or substances, and other conventional materials that can be used as a battery negative electrode active substance can also be used. These negative electrode active substances can be used alone or in combination with two or more.

[0294] In some embodiments, the negative electrode tab or the negative electrode sheet can 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 facing away from each other in the thickness direction thereof, and the negative electrode active material layer is disposed on either one or both of the two surfaces of the negative electrode current collector. In some embodiments, the negative electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, a copper foil can be employed. In the negative electrode current collector, the composite current collector can 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 can be formed by forming a metal material on the polymer material base layer. In the negative electrode current collector, non-limiting examples of the metal material can include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, and the like. In the negative electrode current collector, non-limiting examples of the polymer material base layer can include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), and the like.

[0295] In some embodiments, the negative electrode active material layer can optionally include a conductive agent, denoted as a negative electrode conductive agent. Non-limitingly, the negative electrode conductive agent can include one or more of super-P, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In the negative electrode active material layer, the weight percentage of the negative electrode conductive agent can be 0-10 wt%, further optionally 0-5 wt%, more further optionally 0.1-5 wt%, more further optionally 0.1-3 wt%.

[0296] In some embodiments, the negative electrode active material layer can optionally include a binder, denoted as a negative electrode binder. As a non-limiting example, the negative electrode binder can include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylic resin. Non-limitingly, the weight percentage of the negative electrode binder in the negative electrode active material layer can be 0-10 wt%, further optionally 0-5 wt%, more further optionally 1-5 wt%, more further optionally 1-3 wt%.

[0297] In some embodiments, the negative active material layer optionally comprises other auxiliary agents, such as thickening agents (e.g., sodium carboxymethyl cellulose (CMC-Na)), and the like. The weight percentage of other auxiliary agents in the negative active material layer can be 0-15 wt%, further optionally 0-10 wt%, more further optionally 0-5 wt%, more further optionally 0-3 wt%, more further optionally 0-2 wt%.

[0298] In some embodiments, the negative electrode film (which can be used as a negative electrode sheet) can be prepared by dry mixing the components described above for preparing the negative electrode film, such as the negative active particles, optional negative electrolyte particles, negative conductive agent, optional negative binder, and any other components, and then heating and pressure kneading the mixed material into a dough-like material, hot rolling the dough-like material to form a self-supporting negative electrode sheet, and hot roll-complexing the self-supporting negative electrode sheet with a negative current collector, which can be on at least one side (single-sided or double-sided) of the negative current collector, to obtain the negative electrode film. Non-limitingly, a double planetary mixer can be used for dry mixing. Non-limitingly, a banbury mixer can be used for heating and pressure kneading. The method for assembling a solid-state battery using the negative electrode film can be suitable for industrial batch production. When the negative electrode material is prepared into a negative active material layer using a dry method, the negative conductive agent can be disposed in the negative electrode material, which can improve the electronic conductivity of the negative active material layer.

[0299] In some embodiments, the negative electrode sheet or negative electrode film can be prepared by dispersing the components described above for preparing the negative electrode sheet or negative electrode film, such as the negative active particles, optional negative electrolyte particles, negative conductive agent, negative binder, and any other components, in a solvent (a non-limiting example of which is p-xylene) to form a negative electrode slurry. Further, the negative electrode slurry is coated on at least one side surface of a negative current collector, and after processes such as drying and pressing, the negative electrode sheet or negative electrode film can be obtained. The surface of the negative current collector coated with the negative electrode slurry can be on a single surface of the negative current collector, or on both surfaces of the negative current collector. The solid content of the negative electrode slurry can be 30-70 wt%, optionally 40-60 wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000-10000 mPa·s, optionally 3000-10000 mPa·s. When coating the negative electrode slurry, the coating unit area density (single-sided) can be 1.5-18 mg / cm 2 ~ 18 mg / cm 2 , but not limited thereto. The compaction density of the negative electrode sheet or negative electrode film can be 1.0-2.0 g / cm 3 ~ 2.0 g / cm 3 , optionally 1.0-1.8 g / cm 3 ~ 1.8 g / cm 3 .

[0300] Non-limitingly, the positive electrode sheet, the solid electrolyte membrane sheet and the negative electrode sheet can be sequentially stacked, the solid electrolyte membrane sheet is arranged between the positive electrode sheet and the negative electrode sheet, and a solid-state battery cell is prepared by hot rolling.

[0301] Non-limitingly, the positive electrode sheet, the solid electrolyte membrane sheet and the negative electrode sheet can be sequentially stacked, the solid electrolyte membrane sheet is arranged between the positive electrode sheet and the negative electrode sheet, and a solid-state battery cell is prepared by hot rolling.

[0302] In some embodiments, the solid-state battery cell 5 comprises a solid-state battery cell 52.

[0303] In some embodiments, the solid-state battery cell is a full solid-state battery cell.

[0304] In some embodiments, the solid-state battery cell 52 (which can be a full solid-state battery cell) comprises a positive electrode layer 200, a solid electrolyte layer 100 and a negative electrode layer 300 which are sequentially stacked, for example as shown in FIG. 1.

[0305] In some embodiments, the solid-state battery can comprise an outer package. The outer package can be used to encapsulate the solid-state battery cell described above.

[0306] In some embodiments, the outer package 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 package of the solid-state battery can also be a soft package, such as a pouch soft package. The material of the soft package can be plastic, and further, non-limiting examples of the plastic can include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate, etc.

[0307] The shape of the solid-state battery cell is not particularly limited in the present application, and it can be cylindrical, square or any other shape. For example, FIG. 2 is a square structure of the solid-state battery cell 5 as an example.

[0308] In some embodiments, referring to FIG. 3, the outer package can comprise a shell 51 and a cover plate 53. The shell 51 can comprise 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 communicating with the receiving cavity, and the cover plate 53 can be arranged 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, which can be selected by those skilled in the art according to actual needs.

[0309] The solid-state battery can be a battery module 4 or a battery pack 1.

[0310] The battery module includes at least one solid-state battery cell. The number of solid-state battery cells included in the battery module can be one or more, and a person skilled in the art can select a suitable number according to the application and capacity of the battery module.

[0311] FIG. 4 is a battery module 4 as an example. Referring to FIG. 4, in the battery module 4, a plurality of solid-state battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, other arbitrary arrangements can also be made. Further, the plurality of solid-state battery cells 5 can be fixed by fasteners.

[0312] Optionally, the battery module 4 can also include a housing having an accommodation space, and the plurality of solid-state battery cells 5 are accommodated in the accommodation space.

[0313] In some embodiments, the above-mentioned battery module can also be assembled into a battery pack, and the number of battery modules included in the battery pack can be one or more, and a person skilled in the art can select a suitable number according to the application and capacity of the battery pack.

[0314] FIGS. 5 and 6 are a battery pack 1 as an example. Referring to FIGS. 5 and 6, the battery pack 1 can include a battery box and a plurality of battery modules 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be arranged on the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0315] In some embodiments, the electric device includes the solid-state battery of any of the embodiments provided in the present application.

[0316] Without limitation, the solid-state battery can be used as a power source of an electric device, and can also be used as an energy storage unit of an electric device. The electric device can include a mobile device, an electric vehicle, an electric train, a ship and a satellite, an energy storage system, etc., but is not limited thereto. Among them, the mobile device can be a mobile phone, a notebook computer, etc.; the electric vehicle can be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, an electric motorcycle, an electric tool, etc., but is not limited thereto. The electric device can also be applied to military equipment, aerospace, etc., and can also be applied to hydroelectric, thermal, wind and solar power stations, etc. Energy storage power systems.

[0317] As an electric device, the solid-state battery can be selected according to the use requirements thereof.

[0318] FIG. 7 is an example of a power consuming device 6. The power consuming device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the demand of the power consuming device for high power and high energy density of solid-state batteries, a battery pack or a battery module can be used.

[0319] An example of a device can be a mobile phone, a tablet, a notebook, etc. The device generally requires thinness, and a solid-state battery can be used as a power source.

[0320] Hereinafter, some embodiments of the present application will be described. The embodiments described below are exemplary and are for the purpose of explanation of the present application only, and should not be construed as limiting the present application. In the embodiments, unless otherwise noted, the techniques or conditions are as described above, or as described in the literature in the art, or as described in the product manual. Unless otherwise noted, the reagents or instruments used are conventional products available on the market, or can be synthesized from conventional products available on the market.

[0321] In the following examples, room temperature refers to 20°C to 30°C.

[0322] In the following examples, unless otherwise noted, the amount of "M element (e.g., Se element, Te element, or a combination of both)" is expressed in wt%, which refers to the weight percentage in the sintered mixture. In the following examples, unless otherwise noted, the sintered mixture is the precursor mixture.

[0323] It should be noted that the sulfide all-solid-state battery is used as a non-limiting example of a solid-state battery in the following embodiments and examples.

[0324] In the following examples, unless otherwise noted, the positive active particles NCM 811 The D v 50 of the powder is 4 pm (the positive active material is NCM 811 The D v 50 of the Li6PS5Cl sulfide electrolyte is 1 pm.

[0325] In the present application, unless otherwise noted, the D v 50 refers to the particle size corresponding to the cumulative volume distribution percentage of 50% of the multi-particle mixture.

[0326] The D v 50 is tested as follows:

[0327] In the following examples and comparative examples, the D v50Test confirmation by the following method: device model: MasterSizer 2000 laser particle size analyzer, reference standard procedure: GB / T19077-2016 / ISO 13320:2009, test procedure: take an appropriate amount of sample to be tested (sample concentration is guaranteed to be 8%-12% (w / v) light intensity), add 20 mL of p-xylene (add dispersant ammonium polycarboxylate when testing sulfide solid electrolyte), and simultaneously external ultrasonic for 5 min (53 KHz / 120 W), ensure that the sample is completely dispersed, and then determine the sample according to the GB / T19077-2016 / ISO 13320:2009 standard.

[0328] I. Preparation of sulfide solid electrolyte, solid electrolyte film, and all-solid-state battery

[0329] (I) Preparation of sulfide solid electrolyte

[0330] The target chemical formula is Li 6-x PS 5-x-y M y T 1+x Referring to Table 1, the M element is one or both of Se and Te elements, and the T element is one or both of Cl and Br elements.

[0331] Example 1. The M element is Se, the T element is Cl, and the target chemical formula is Li 5.7 PS 4.68 Se 0.02 T 1.3 .

[0332] According to the stoichiometric ratio of raw materials Li 5.7 PS 4.7 Cl 1.3 , 2.2 mol of Li2S, 0.5 mol of P2S5 and 1.3 mol of LiCl raw material powder were weighed, and 3wt% of elemental selenium was additionally weighed, mixed, and a precursor mixture was obtained. The precursor mixture was placed in an atmosphere (argon) furnace and sintered at 530°C for 8h, and then the sintered body was crushed to obtain a powdery argyrodite-type sulfide solid electrolyte.

[0333] Example 2-3. The target chemical formula is Li 5.7 PS 4.65 Se 0.05 T 1.3 (Example 2), Li 5.7 PS 4.61 Se 0.09 T 1.3 (Example 3).

[0334] A sulfide solid electrolyte was prepared by substantially the same method as in Example 1, except that the amount of selenium elemental added was different. Except that the amount of selenium elemental added was changed to 6 wt% (Example 2) and 10 wt% (Example 3), respectively, the other steps were the same as in Example 1.

[0335] Example 4. The target chemical formula was Li 5.95 PS 4.9 Se 0.05 Cl 1.05 .

[0336] A sulfide solid electrolyte was prepared by substantially the same method as in Example 1, except that the stoichiometric ratio of raw materials of Li, P, S, and Cl was Li 5.95 PS 4.95 Cl 1.05 , and the amount of selenium elemental added was 6 wt%.

[0337] Example 5. The target chemical formula was Li 5.9 PS 4.85 Te 0.05 Br 1.1 .

[0338] A sulfide solid electrolyte was prepared by substantially the same method as in Example 1, except that the stoichiometric ratio of raw materials of Li, P, S, and Br was Li 5.9 PS 4.9 Br 1.1 , and the amount of selenium elemental was replaced with tellurium elemental, and the amount of tellurium elemental added was 6 wt%.

[0339] Example 6. The target chemical formula was Li 5.9 PS 4.87 Se 0.02 Te 0.01 Cl 0.6 Br 0.5 .

[0340] A sulfide solid electrolyte was prepared by substantially the same method as in Example 1, except that the stoichiometric ratio of raw materials of Li, P, S, Cl, and Br was Li 5.9 PS 4.9 Cl 0.6 Br 0.5 , the amount of selenium elemental added was 3 wt%, and the amount of tellurium elemental added was 2 wt%.

[0341] Example 7. The target chemical formula was Li 5.95 PS 4.85 Se 0.1 Cl 1.05 .

[0342] A sulfide solid electrolyte was prepared in substantially the same manner as in Example 1, except that the stoichiometric ratios of the raw materials of Li, P, S and Cl were changed to Li 5.95 PS 4.95 Cl 1.05 and the amount of selenium added was 12 wt%.

[0343] Example 8. The target chemical formula was Li 5.5 PS 4.47 Se 0.03 Cl 1.5 .

[0344] The stoichiometric ratios of the raw materials of Li 5.5 PS 4.5 Cl 1.5 were Li2S: P2S5: LiCl = 2.0: 0.5: 1.5, respectively, and 4 wt% of selenium was additionally added. The raw material powders were mixed to obtain a precursor mixture. The precursor mixture was sintered at 500°C for 8 hours in an atmosphere (argon) furnace, and then the sintered body was crushed to obtain a sulfide solid electrolyte powder of argyrodite type.

[0345] Examples 9-10. The target chemical formula was Li 5.5 PS 4.44 Se 0.06 Cl 1.5 (Example 9), Li 5.5 PS 4.41 Se 0.09 Cl 1.5 (Example 10).

[0346] The remaining steps of Examples 9-10 were the same as those of Example 8, except that the amount of selenium added was changed to 7 wt% and 10 wt%, respectively.

[0347] Example 11. The target chemical formula was Li 5.2 PS 4.17 Se 0.03 Cl 1.8 .

[0348] The stoichiometric ratios of the raw materials of Li 5.2 PS 4.2 Cl 1.8 were Li2S: P2S5: LiCl = 1.7: 0.5: 1.8, respectively, and 4 wt% of selenium was additionally added. The raw material powders were mixed to obtain a precursor mixture. The precursor mixture was sintered at 480°C for 8 hours in an atmosphere (argon) furnace, and then the sintered body was crushed to obtain a sulfide solid electrolyte powder of argyrodite type.

[0349] Example 12-13. The target chemical formula is Li 5.2 PS 4.14 Se 0.06 Cl 1.8 (Example 12), Li 5.2 PS 4.11 Se 0.09 Cl 1.8 (Example 13).

[0350] The remaining steps of Examples 12-13 are the same as those of Example 11, except that the added amount of elemental selenium is changed to 7wt% and 10wt%, respectively.

[0351] Example 14. The target chemical formula is Li 5.2 PS 4.1 Se 0.1 Cl 1.8 .

[0352] The remaining steps of Example 14 are the same as those of Example 11, except that the added amount of elemental selenium is changed to 12wt%.

[0353] Example 15. The target chemical formula is Li 5.2 PS 4.1 Se 0.08 Te 0.02 Cl 1.5 Br 0.3 .

[0354] A sulfide solid electrolyte is prepared by substantially the same method as that of Example 11, except that the stoichiometric ratio of raw materials of Li, P, S and Cl is changed to Li 5.2 PS 4.2 Cl 1.5 Br 0.3 The remaining steps of Example 15 are the same as those of Example 11, except that the added amount of elemental selenium is 9wt% and the added amount of elemental tellurium is changed to 3wt%, respectively.

[0355] Comparative Example 1. The target chemical formula is Li6PS5Cl 1.3 .

[0356] According to the stoichiometric ratio of raw materials of Li6PS5Cl, 2.5mol of Li2S, 0.5mol of P2S5 and 1mol of LiCl raw material powders are weighed, respectively, and mixed to obtain a raw material mixture. The raw material mixture is placed in an atmosphere (argon) furnace and sintered at 550°C for 8h. Then, the sintered body is crushed to obtain a powdery argyrodite-type sulfide solid electrolyte.

[0357] Comparative Example 2. The target chemical formula is Li 5.7 PS 4.7 Cl 1.3 .

[0358] According to the stoichiometric ratio of raw materials Li 5.7 PS 4.7 Cl 1.3 , respectively, 2.2 mol of Li2S, 0.5 mol of P2S5 and 1.3 mol of LiCl raw material powders were weighed, mixed uniformly to obtain a raw material mixture, and the raw material mixture was placed in an atmosphere (argon) furnace and sintered at 530°C for 8h. Then, the sintered body was crushed to obtain a sulfide solid electrolyte powder of argyrodite type.

[0359] Comparative Example 3. The target chemical formula is Li 5.5 PS 4.5 Cl 1.5 .

[0360] According to the stoichiometric ratio of raw materials Li 5.5 PS 4.5 Cl 1.5 , respectively, 2.0 mol of Li2S, 0.5 mol of P2S5 and 1.5 mol of LiCl raw material powders were weighed, mixed uniformly to obtain a raw material mixture, and the raw material mixture was placed in an atmosphere (argon) furnace and sintered at 500°C for 8h. Then, the sintered body was crushed to obtain a sulfide solid electrolyte powder of argyrodite type.

[0361] Comparative Example 4. The target chemical formula is Li 5.2 PS 4.2 Cl 1.8 .

[0362] According to the stoichiometric ratio of raw materials Li 5.2 PS 4.2 Cl 1.8 , respectively, 1.7 mol of Li2S, 0.5 mol of P2S5 and 1.8 mol of LiCl raw material powders were weighed, mixed uniformly to obtain a raw material mixture, and the raw material mixture was placed in an atmosphere (argon) furnace and sintered at 480°C for 8h. Then, the sintered body was crushed to obtain a sulfide solid electrolyte powder of argyrodite type.

[0363] (II) Preparation of solid electrolyte membrane (in the form of a solid electrolyte membrane sheet) and all-solid-state battery

[0364] Examples 1-15, respectively, correspond to the sulfide solid electrolyte powders prepared in the first step of Examples 1-15:

[0365] In an argon atmosphere, the sulfide solid electrolyte powder (prepared in Examples 1-15) was pressed into a dense solid electrolyte membrane sheet under the action of 360MPa.

[0366] In an argon atmosphere, the NCM 811The powder, sulfide solid electrolyte Li6PS5Cl, conductive carbon fiber (VGCF), and binder PTFE are weighed in a ratio of 85:13:1:1, mixed uniformly in a double planetary mixer, then the uniformly mixed powder is kneaded into a mass material in an internal mixer under heating and pressure, and then hot-rolled into a self-supporting positive electrode sheet at 80℃, and then hot-rolled with the current collector Al foil to obtain a positive electrode sheet (positive electrode film).

[0367] The positive electrode sheet is placed on one side of the solid electrolyte film, and an InLi alloy is stacked as a negative electrode layer on the other side of the solid electrolyte film to assemble a full solid-state battery, at this time, the solid electrolyte film is used as a solid electrolyte layer, and the positive electrode sheet is used as a positive electrode layer. The battery test window is 2.6-4.3V vs Li.

[0368] Comparative Examples 1-4:

[0369] The same method as in Example 1 is used, except that the sulfide solid electrolyte powder used to prepare the solid electrolyte film is replaced with the sulfide solid electrolyte powder prepared in Comparative Examples 1-4.

[0370] Table 1. Target chemical formula Li of the sulfide solid electrolyte prepared in Examples 1-15 and Comparative Examples 1-4 6-x PS 5-x-y M y T 1+x The relevant parameters (M element type and content, T element type and content, x, y) in the above table 1 can be referred to.

[0371] Table 1. Chemical formula related information and M elemental addition amount information of the sulfide solid electrolyte prepared in Examples 1-15 and Comparative Examples 1-4.

[0372] In Table 1, the "Se elemental addition amount" and the "Te elemental addition amount" are the mass proportions of Se elemental and Te elemental relative to the sintered mixture, with the percentage unit being wt%. In each example, unless otherwise specified, the sintered mixture is the precursor mixture.

[0373] II. The positive electrode layer is provided with the sulfide solid electrolyte and the preparation of the solid-state battery (full solid-state secondary battery, sulfide full solid-state battery) provided in the present application.

[0374] Examples P1 to P15, respectively, correspond to the sulfide solid electrolyte powder prepared in the first step of Examples 1-15:

[0375] In an argon atmosphere, the positive electrode active particles NCM 811The powders, sulfide solid electrolyte powder (obtained by preparing Examples 1-15, as positive electrode electrolyte particles), conductive carbon fiber (VGCF, as positive electrode conductive agent) and binder PTFE were weighed in a weight ratio of 85:13:1:1, mixed uniformly in a double planetary mixer, and then the uniformly mixed powders were kneaded into a mass material in an internal mixer under heating and pressure, and then hot-rolled into a self-supporting positive electrode sheet at 80°C, and then hot-rolled with a current collector Al foil to obtain a positive electrode sheet (positive electrode film).

[0376] The sulfide solid electrolyte powder Li6PS5Cl was pressed into a dense solid electrolyte film under the action of 360 MPa in an argon atmosphere.

[0377] The positive electrode sheet was placed on one side of the solid electrolyte film, and an InLi alloy was stacked as a negative electrode layer on the other side of the solid electrolyte film to assemble a full solid-state battery, at this time, the solid electrolyte film was used as a solid electrolyte layer, and the positive electrode sheet was used as a positive electrode layer. The battery test window was 2.6-4.3 V vs Li.

[0378] Comparative Example P1.

[0379] A full solid-state battery was prepared by substantially the same method as in Example P8, except that the positive electrode electrolyte particles in the composite positive electrode powder were replaced by Li6PS5Cl in Comparative Example 1.

[0380] III. The negative electrode layer is provided with the sulfide solid electrolyte and the preparation of the solid-state battery (full solid-state secondary battery, sulfide full solid-state battery) provided in the present application.

[0381] Examples N1 to N15, respectively, correspond to the sulfide solid electrolyte powder prepared in the first step of Examples 1-15:

[0382] The sulfide solid electrolyte powder Li6PS5Cl was pressed into a dense solid electrolyte film under the action of 360 MPa in an argon atmosphere.

[0383] The NCM 811 The powders, sulfide solid electrolyte Li6PS5Cl, conductive carbon fiber (VGCF) and binder PTFE were weighed in a weight ratio of 85:13:1:1, manually ground in a mortar to mix uniformly to obtain a composite positive electrode powder. The composite positive electrode powder was evenly spread on the surface of one side of the solid electrolyte film, and cold-pressed into a sheet at a pressure of 420 MPa for 5 min to form a composite film composed of a positive electrode layer and a solid electrolyte layer.

[0384] Under argon atmosphere, the negative active particle Si powder, sulfide solid electrolyte powder (obtained by preparing Examples 1-15, as negative electrolyte particles) and negative binder PVDF were dispersed in solvent p-xylene (solid content 60wt%) according to weight ratio 80:17:3, and the coating surface density (excluding solvent) was 2.5mg / cm 2 The other side of the solid electrolyte layer in the composite film was coated with a negative electrode layer, and dried to form a negative electrode layer, to obtain a sulfide all-solid-state battery, which includes a positive electrode layer (corresponding to the positive electrode film), a solid electrolyte layer (corresponding to the solid electrolyte film), and a negative electrode layer (corresponding to the negative electrode film) stacked in sequence.

[0385] Comparative Example N1.

[0386] An all-solid-state battery was prepared by substantially the same method as in Example N8, except that the negative electrolyte particles in the negative electrode layer were replaced by Li6PS5Cl in Comparative Example 1.

[0387] IV. Test and analysis of materials

[0388] (I) Test and analysis method

[0389] 1. Elemental analysis

[0390] An inductively coupled plasma spectrometer (ICP instrument) was used to analyze the elemental species and proportion of the sulfide solid electrolyte, to determine its chemical formula.

[0391] Test instrument: ThermoFisher ICAP Pro.

[0392] 2. Crystal phase analysis

[0393] X-ray diffraction (XRD) patterns were used to determine whether the sulfide solid electrolyte included argyrodite-type crystal phase and the amount of impurities.

[0394] Sample to be tested: sulfide solid electrolyte powder.

[0395] Test instrument: Bruker-D8 advance. Cu target Kα1 ray was used, with a wavelength λ of 0.15406 nm, and the X-ray tube was controlled at 40 kV and 40 mA, with a 2θ(°) scanning range of 10°-80° and a 2θ(°) scanning speed of 0.02° / s.

[0396] Analysis method: According to the comparison with the XRD standard spectrum of Li6PS5Cl, it was confirmed whether the sulfide solid electrolyte to be tested included argyrodite-type crystal phase.

[0397] 3. Ion conductivity test

[0398] Ion conductivity was determined by electrochemical impedance spectroscopy (EIS).

[0399] Test sample: sulfide solid electrolyte powder.

[0400] Test sample preparation: 120 mg of the solid electrolyte powder to be tested was poured into a 10 mm diameter tablet press die, and the electrolyte powder was pressed into a dense disc at 360 MPa to obtain a solid electrolyte membrane as the test sample.

[0401] Test method: The prepared solid electrolyte membrane was clamped in the mold with a 10 mm diameter cylindrical stainless steel current collector at 120 MPa, and then the current collector was connected to an electrochemical workstation. Electrochemical impedance spectroscopy (EIS) was performed on the electrolyte disc at a bias of 10 mV and a frequency range of 10 6 Hz to 10 Hz. The intersection of the curve in the electrochemical impedance spectrum from high frequency to low frequency with the Z' axis was recorded as the resistance R, and the ionic conductivity (σ) was calculated by formula (1):

[0402] where d is the thickness of the solid electrolyte membrane, and A is the contact area of the electrolyte disc and the current collector.

[0403] The sulfide solid electrolyte powders prepared in Examples 1-15 correspond to Test Examples 1-15, respectively; the sulfide solid electrolyte powders prepared in Comparative Examples 1-4 correspond to Test Comparative Examples 1-4, respectively; the test results can be referred to Table 2 "Ionic conductivity".

[0404] 4. Initial discharge capacity

[0405] Test method: The assembled all-solid-state battery was charged to 3.68 V (vs. Li potential 4.3 V) at a current density of 0.1 C, and then discharged to 2.18 V (vs. Li potential 2.8 V) at a current density of 0.1 C, to obtain the initial discharge capacity of the battery. The battery was tested at 25±3°C, where 1C=200 mA / g. The test results can be referred to Table 3.

[0406] 5. Rate performance

[0407] Test method: The charge rate of the all-solid-state battery was fixed at 0.1 C, and then discharged at rates of 0.1 C, 0.33 C, 1 C, 2 C, and 3 C, respectively, with 3 cycles at each rate. The voltage test window of the battery was 2.8-4.3 V vs. Li+ / Li, and the battery was tested at 25±3°C, where 1C=200 mA / g. The test results can be referred to Table 3.

[0408] (B) Analysis of test results

[0409] 1. Elemental analysis

[0410] The chemical formula of the sulfide solid electrolyte prepared in each of Examples 1-15 and each of Comparative Examples 1-4 was confirmed by ICP test to be substantially consistent with the target chemical formula. Taking Example 8 as an example, the target sulfide solid electrolyte Li 5.5 PS 4.47 Se 0.03 Cl 1.5 The actual test results of the elemental components of Example 8 were: the atomic number ratio of Li:P:S:Se:Cl = 5.51:1.02:4.40:0.03:1.49.

[0411] 2、According to the XRD analysis results, the sulfide solid electrolytes prepared in each of Examples 1-15 and each of Comparative Examples 1-4 all formed argyrodite-type crystal phases. In addition, the content of impurities in the argyrodite-type sulfide solid electrolytes of each of the examples was relatively low. See Table 2. As an example, the X-ray diffraction (XRD) pattern of the sulfide solid electrolyte prepared in Example 8 and Comparative Example 3 can be seen in FIG. 8.

[0412] 3、Ionic conductivity

[0413] The test results of the hydrogen sulfide release amount and the ionic conductivity of the sulfide solid electrolytes prepared in each of Examples 1-15 and each of Comparative Examples 1-4 can be seen in Table 2.

[0414] Compared with Comparative Example 1, the sulfide solid electrolytes Li 6-x PS 5-x-y M y T 1+x satisfy x>0 and y>0; compared with Comparative Example 1, the sulfide solid electrolytes prepared in each of Examples 1-15 all have higher ionic conductivity. The sulfide solid electrolytes prepared in Examples 1-2 compared with Comparative Example 2, Examples 8-10 compared with Comparative Example 3, and Examples 11-14 compared with Comparative Example 4 also have significantly reduced hydrogen sulfide release amount, while also having good ionic conductivity. See Table 2.

[0415] 4、Battery performance

[0416] Compared with Comparative Example 1, the solid-state batteries of Examples 1-15 all have better initial discharge capacity and rate performance. In addition, the solid-state batteries prepared in Examples 1-2 compared with Comparative Example 2, Examples 8-10 compared with Comparative Example 3, and Examples 11-14 compared with Comparative Example 4 all have lower impurity content and higher ionic conductivity. See Table 3.

[0417] As an example, compared with Example P8, the positive electrode layer of Comparative Example P1 does not have the sulfide solid electrolyte provided in the first aspect of the present application, and the initial discharge capacity and rate performance are both significantly deteriorated. See Table 3.

[0418] As an example, compared with embodiment N2, the first discharge capacity and rate performance of the negative electrode layer of comparative example N1 are both significantly deteriorated, because the sulfide solid electrolyte provided by the first aspect of the present application is not arranged in the negative electrode layer. See Table 3.

[0419] The solid-state batteries of embodiments 1-15 all use the sulfide solid electrolyte described in the first aspect of the present application in the solid electrolyte layer, effectively reducing the resistance of the solid-state battery, and the solid-state battery has excellent rate performance and can achieve better electrochemical performance at high rates.

[0420] Embodiments P1-P15 use the sulfide solid electrolyte described in the first aspect of the present application as the positive electrode electrolyte particles in the positive electrode layer, which not only reduces the sheet resistance, but also promotes the capacity of the positive electrode active material in the positive electrode layer.

[0421] Embodiments N1-N15 use the sulfide solid electrolyte described in the first aspect of the present application as the negative electrode electrolyte particles in the negative electrode layer, which not only reduces the sheet resistance, but also promotes the capacity of the positive electrode active material in the negative electrode layer.

[0422] Table 2.

[0423] Table 3.

[0424] The above description of various embodiments tends to emphasize the differences between various embodiments, and the same or similar parts can be referred to each other, and for brevity, will not be described herein. The technical features of the above-described embodiments can be combined in any manner, and for brevity, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not contradict, it should be considered as within the scope of the present disclosure.

[0425] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are only examples, and embodiments having substantially the same configuration and playing the same role and effect as the technical idea within the scope of the technical solutions of the present application are all included in the technical scope of the present application. The above-described embodiments only express several embodiments of the present application, and the description is more detailed, but it should not be construed as limiting the scope of the patent. In addition, within the scope of the main idea of the present application, various modifications that can be thought of by those skilled in the art, combinations of part of the components in the embodiments to construct other ways are also included in the scope of the present application.

Claims

1. A sulfide solid electrolyte comprising an argyrodite-type crystal phase; The argyrodite-type crystal phase includes Li element, P element, S element, M element and T element; wherein, The M element is selected from one or both of Se and Te, and the T element is selected from one or both of Cl and Br; In the argyrodite-type crystal phase, the atomic number ratio of the T element to the P element is 1+x, and x>0; In the argyrodite-type crystal phase, the atomic number ratio of the M element to the P element is denoted as y, and y>0.

2. The sulfide solid electrolyte according to claim 1, wherein In the argyrodite-type crystal phase, 0 <x≤0.8。 3. The sulfide solid electrolyte according to claim 1 or 2, wherein In the argyrodite-type crystal phase, 0 <y≤0.1。 4. The sulfide solid electrolyte according to any one of claims 1 to 3, wherein In the argyrodite-type crystal phase, the atomic number ratio of Li element, P element, S element, M element and T element is (6-x):1:(5-xy):y:(1+x), wherein 0 <x≤0.8,0<y≤0.1。 5. The sulfide solid electrolyte according to any one of claims 1 to 4, wherein The chemical formula of the argyrodite-type crystal phase is Li 6-x PS 5-x-y M y T 1+x .

6. The sulfide solid electrolyte according to any one of claims 1 to 4, wherein The chemical formula of the argyrodite-type crystal phase is Li 6-x PS 5-x-y Se y Cl 1+x .

7. The sulfide solid electrolyte according to any one of claims 1 to 6, wherein The argyrodite-type crystal phase satisfies one or more of the following characteristics: In the argyrodite-type crystal phase, 0.05≤x≤0.8; optionally, 0.1≤x≤0.8; further optionally, 0.3≤x≤0.8; In the argyrodite-type crystal phase, 0.02≤y≤0.1; optionally, 0.02≤y≤0.

09.

8. The sulfide solid electrolyte according to any one of claims 1 to 6, wherein 0.3≤x≤0.8, 0.02≤y≤0.

09.

9. The sulfide solid electrolyte according to any one of claims 1 to 8, wherein In the argyrodite-type crystal phase, the atomic number ratio of the S element to the P element is denoted as 5-xy, and 4.1≤(5-xy)<5.

0.

10. The sulfide solid electrolyte according to claim 9, wherein 4.1<(5-xy)<4.

7.

11. The sulfide solid electrolyte according to any one of claims 1 to 10, wherein The argyrodite-type crystal phase satisfies one or both of the following characteristics: In the argyrodite-type crystal phase, the T element includes Cl element; In the argyrodite-type crystal phase, the M element includes Se.

12. The sulfide solid electrolyte according to any one of claims 1 to 11, wherein The argyrodite-type crystal phase satisfies one or both of the following characteristics: In the argyrodite-type crystal phase, the atomic number ratio of the Cl element to the Br element is greater than or equal to 1; In the argyrodite-type crystal phase, the atomic number ratio of the Se element to the Te element is greater than or equal to 1.

13. The sulfide solid electrolyte according to any one of claims 1 to 12, wherein The argyrodite-type crystal phase has any of the following chemical formulas: Li 5.7 PS 4.65 Se 0.05 Cl 1.3 、Li 5.5 PS 4.44 Se 0.06 Cl1Br 0.5 、Li 5.5 PS 4.44 Se 0.05 Te 0.01 Cl1Br 0.5 He Li 5.5 PS 4.44 Se 0.06 Cl 1.5 .

14. The sulfide solid electrolyte according to any one of claims 1 to 13, wherein The 2θ (°) diffraction angle in the X-ray diffraction pattern of the sulfide solid electrolyte has a characteristic peak consistent with the argyrodite-type crystal phase.

15. The sulfide solid electrolyte according to claim 14, which satisfies at least one of the following characteristics: The 2θ (°) diffraction angle in the X-ray diffraction pattern of the sulfide solid electrolyte has peaks at 15.5±δ°, 18.1±δ°, 25.6±δ°, 30.1±δ°, 31.4±δ°, 39.8±δ°, 45.1±δ°, 47.9±δ° and 52.5±δ°, wherein, δ is 0.2 or 0.1; There is no LiT impurity phase peak in the X-ray diffraction pattern of the sulfide solid electrolyte; The X-ray diffraction pattern of the sulfide solid electrolyte has no diffraction peaks at 2θ (°) diffraction angles of 34.9±0.2°, 29.2±0.2°, and 33.9±0.2°; The X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα radiation; The X-ray diffraction pattern of the sulfide solid electrolyte is obtained by powder X-ray diffraction testing.

16. A method for preparing a sulfide solid electrolyte, comprising the following steps: A precursor mixture comprising Li2S, P2S5, an optional sulfur element, an M element and LiT is provided in accordance with a desired raw material stoichiometric ratio; wherein, The M element is selected from one or both of Se and Te, T is a halogen, and LiT is selected from one or both of LiCl and LiBr; The precursor mixture is sintered in an inert atmosphere to prepare a sulfide solid electrolyte including an argyrodite-type crystal phase; in the argyrodite-type crystal phase, the atomic number ratio of the T element to the P element is recorded as 1+x, and the atomic number ratio of the M element to the P element is recorded as y, and the argyrodite-type crystal phase satisfies x>0 and y>0.

17. The method for preparing a sulfide solid electrolyte according to claim 16, which satisfies one or more of the following characteristics: In the step of sintering the precursor mixture in an inert atmosphere, the sintering temperature is 450° C. to 530° C.; The prepared sulfide solid electrolyte is the sulfide solid electrolyte described in any one of claims 1 to 15.

18. A solid electrolyte membrane comprising at least one of the sulfide solid electrolyte according to any one of claims 1 to 15 and the sulfide solid electrolyte prepared by the preparation method according to claim 16 or 17.

19. An electrode plate, comprising an electrode active material layer, wherein the electrode active material layer comprises an electrode active substance, and further comprises at least one of the sulfide solid electrolyte according to any one of claims 1 to 15 and the sulfide solid electrolyte prepared by the preparation method according to claim 16 or 17.

20. The electrode plate according to claim 19, wherein: The electrode sheet is a positive electrode sheet, the electrode active material layer is referred to as a positive electrode active material layer, and the electrode active substance is referred to as a positive electrode active substance; Alternatively, the electrode plate is a negative electrode plate, the electrode active material layer is recorded as a negative electrode active material layer, and the electrode active substance is recorded as a negative electrode active substance.

21. A solid-state battery comprising at least one of the sulfide solid electrolyte according to any one of claims 1 to 15, the sulfide solid electrolyte prepared by the preparation method according to claim 16 or 17, the solid electrolyte membrane according to claim 18, and the electrode sheet according to claim 19 or 20.

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

23. An electrical device comprising at least one of the sulfide solid electrolyte according to any one of claims 1 to 15, the sulfide solid electrolyte prepared by the preparation method according to claim 16 or 17, the solid electrolyte membrane according to claim 18, the electrode plate according to claim 19 or 20, and the solid-state battery according to claim 21 or 22.

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