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

Abstract

The invention relates to a sulfide solid electrolyte and a preparation method thereof, a solid electrolyte membrane, an electrode plate, a solid-state battery and an electric device. The sulfide solid electrolyte comprises an argyrodite type crystal phase; the argyrodite type crystal phase comprises an element Li, an element P, an element S, an element M and an element T; wherein the M element is selected from one or two of Se element and Te element, and the T element is selected from one or two of Cl element and Br element; in the argyrodite type crystal phase, the atomic number ratio of the element T to the element P is denoted as 1 + x, and xgt; 0; in the argyrodite-type crystal phase, the atomic number ratio of M element to P element is denoted as y, and ygt; 0. The sulfide solid electrolyte has relatively high ionic conductivity and can effectively improve the rate capability of a solid-state battery.

Description

Technical Field

[0001] The present application relates to the field of secondary battery technology, further to the field of solid-state battery technology, and further to sulfide solid electrolytes and preparation methods thereof, solid electrolyte membranes, electrode plates, solid-state batteries and electrical devices. Background Art

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

[0003] Solid-state batteries introduce non-flammable solid electrolytes to replace the organic electrolytes in traditional liquid secondary batteries, significantly improving battery safety. Among the numerous solid electrolyte materials, sulfide solid electrolytes, due to their ultra-high ionic conductivity and excellent mechanical properties, have become the most practical and industrially viable solid electrolyte material. However, as a sulfide solid electrolyte, the ionic conductivity of the sintered products of argyrodite-type sulfide solid electrolytes often falls short of expectations, resulting in suboptimal discharge capacity and rate performance of solid-state batteries. Summary of the Invention

[0004] In view of the above problems, according to various embodiments and examples of the present application, this application provides a sulfide solid electrolyte and its preparation method, a solid electrolyte membrane, an electrode plate, a solid-state battery, and an electrical device. This sulfide solid electrolyte has high ionic conductivity and can effectively improve the rate performance of solid-state batteries.

[0005] In a first aspect of the present application, a sulfide solid electrolyte is provided, comprising an argyrodite-type crystal phase;

[0006] The argyrodite-type crystal phase includes Li, P, S, M and T elements; 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;

[0007] In the argyrodite-type crystal phase, the atomic number ratio of the T element to the P element is 1+x, and x>0;

[0008] 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.

[0009] 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, wherein the argyrodite-type crystal phase contains Li, P, S, and T (T is one or both of Cl and Br). When the atomic number ratio (1+x) of T element to P element is greater than 1 (x>0 at this time), by introducing M element (which can be selected from one or both of Se and Te elements), on the one hand, excess T element can generate more lithium vacancies; on the other hand, it can be used to Using the T element to exert a smaller Coulomb binding force on lithium ions can make lithium ions migrate more easily, which is beneficial to promoting lithium ion diffusion and improving the ionic conductivity of the solid electrolyte; on the other hand, the M element can compensate for the sulfur (S) loss of the sulfide raw material during the sintering process, inhibit the formation of impurities such as LiT, and is also beneficial 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 transmission channel in the crystal structure. The aforementioned multiple synergistic effects can significantly improve the ionic conductivity of the argyrodite-type sulfide solid electrolyte.

[0010] 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 the solid electrolyte layer, the positive electrode layer and the negative electrode layer, which can effectively reduce the resistance of the solid-state battery, improve the rate performance of the solid-state battery, and enable the solid-state battery to have better electrochemical performance at high rates.

[0011] When the sulfide solid electrolyte is used as 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.

[0012] When the sulfide solid electrolyte is used as 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.

[0013] In some embodiments, in the argyrodite-type crystal phase, 0 <x≤0.8。

[0014] By controlling x within the aforementioned range, the T element can be controlled within a more optimal range, which is beneficial to better improve the ionic conductivity of the sulfide solid electrolyte and can also simultaneously control the impurity content at a lower proportion.

[0015] In some embodiments, in the argyrodite-type crystal phase, 0 <y≤0.1。

[0016] 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.

[0017] 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-xy):y:(1+x), wherein 0 <x≤0.8,0<y≤0.1。

[0018] 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 .

[0019] When the argyrodite-type crystal phase has the aforementioned chemical formula, it is beneficial to better suppress the impurity phase and better improve the ionic conductivity of the sulfide solid electrolyte.

[0020] 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 .

[0021] When the M element includes Se and the T element includes Cl, the sulfide solid electrolyte is beneficial to having better ionic conductivity.

[0022] In some embodiments, the argyrodite-type crystal phase satisfies one or more of the following characteristics:

[0023] In the argyrodite-type crystal phase, 0.05≤x≤0.8; optionally, 0.1≤x≤0.8; further optionally, 0.3≤x≤0.8;

[0024] In the argyrodite-type crystal phase, 0.02≤y≤0.1; optionally, 0.02≤y≤0.09.

[0025] In some embodiments, 0.3≤x≤0.8, 0.02≤y≤0.09.

[0026] By controlling one or both of the parameters x and y within the aforementioned ranges, the contents of the T and M elements can be adjusted to more appropriate levels, which is beneficial for improving the ionic conductivity of the sulfide solid electrolyte. Specifically, by controlling y within the aforementioned range, the M element can be controlled within an even more optimal range, further facilitating the suppression of impurities and improving the ionic conductivity of the sulfide solid electrolyte.

[0027] In some embodiments, 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.

[0028] In some embodiments, 4.1<(5-xy)<4.7.

[0029] When the atomic number ratio of the S element to the P element (5-xy) is controlled within the aforementioned range, controlling the contents of x and y is more conducive to suppressing the impurity phase and improving the ionic conductivity of the sulfide solid electrolyte.

[0030] In some embodiments, the argyrodite-type crystal phase satisfies one or both of the following characteristics:

[0031] In the argyrodite-type crystal phase, the T element includes Cl element;

[0032] In the argyrodite-type crystal phase, the M element includes Se.

[0033] When the M element includes Se, it is beneficial for the sulfide solid electrolyte to have better ionic conductivity.

[0034] When the T element includes the Cl element, it is beneficial for the sulfide solid electrolyte to have better ionic conductivity.

[0035] In some embodiments, the argyrodite-type crystal phase satisfies one or both of the following characteristics:

[0036] 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;

[0037] 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.

[0038] 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.

[0039] 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 He Li 5.5 PS 4.44 Se 0.06 Cl 1.5 .

[0040] By providing one or more aforementioned argyrodite-type crystal phases in the sulfide solid electrolyte, it is more advantageous to reduce impurity phases and improve ionic conductivity.

[0041] In some embodiments, 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.

[0042] In some embodiments, the sulfide solid electrolyte satisfies at least one of the following characteristics:

[0043] 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;

[0044] There is no LiT impurity phase peak in the X-ray diffraction pattern of the sulfide solid electrolyte;

[0045] 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°;

[0046] The X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα radiation;

[0047] The X-ray diffraction pattern of the sulfide solid electrolyte is obtained by powder X-ray diffraction testing.

[0048] The chemical composition and amount of impurities in sulfide solid electrolytes can be confirmed by X-ray diffraction (XRD) detection.

[0049] In a second aspect of the present application, a method for preparing 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.

[0050] In some embodiments, the method for preparing the sulfide solid electrolyte comprises the following steps:

[0051] Providing a precursor mixture comprising Li2S, P2S5, an optional sulfur element, M element, and LiT according to a desired raw material stoichiometric ratio; wherein the M element is selected from one or both of Se element and Te element, T is a halogen, and LiT is selected from one or both of LiCl element and LiBr element;

[0052] 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.

[0053] In some embodiments, the method for preparing the sulfide solid electrolyte satisfies one or more of the following characteristics:

[0054] In the step of sintering the precursor mixture in an inert atmosphere, the sintering temperature is 450° C. to 530° C.;

[0055] The prepared sulfide solid electrolyte is the sulfide solid electrolyte described in the first aspect of the present application.

[0056] In a third aspect of the present application, a solid electrolyte membrane is provided, 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.

[0057] For a solid electrolyte membrane provided with the aforementioned sulfide solid electrolyte, the resistance can be effectively reduced, and the corresponding solid-state battery can be given better rate performance, so that the solid-state battery can have better electrochemical performance at high rates.

[0058] In a fourth aspect of the present application, an electrode plate is provided, which includes an electrode active material layer, wherein the electrode active material layer includes an electrode active substance, and also 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.

[0059] In some embodiments, the electrode plate is a positive electrode plate, 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;

[0060] 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.

[0061] For electrode plates provided with the aforementioned sulfide solid electrolyte, the internal resistance of the plates can be reduced, the capacity of the active material in the plates can be promoted, and the corresponding solid-state battery can be given better rate performance.

[0062] The electrode plate can be a positive electrode plate or a negative electrode plate.

[0063] In the fifth aspect of the present application, a solid-state battery is provided, which includes 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 membrane described in the third aspect of the present application, and at least one of the electrode pole pieces described in the fourth aspect of the present application.

[0064] In some embodiments, the solid-state battery is a sulfide all-solid-state battery.

[0065] For a solid-state battery provided with the aforementioned sulfide solid electrolyte, the sulfide solid electrolyte may be provided at one or more of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer.

[0066] In the sixth aspect of the present application, an electrical device 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 membrane described in the third aspect of the present application, the electrode plate described in the fourth aspect of the present application, and the solid-state battery described in the fifth aspect of the present application.

[0067] The details of one or more embodiments or examples of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to better describe and illustrate the embodiments, examples or examples provided in this application, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered as limiting the scope of the disclosed application, the embodiments, examples or examples currently described, and any of the best modes of these applications currently understood. It should also be noted that the accompanying drawings are drawn in a simplified form and are only used to assist in the explanation of this application for convenience and clarity. The various dimensions of each component shown in the accompanying drawings are arbitrarily shown and may be accurate or not drawn to scale. For example, in order to make the illustration clearer, the dimensions of the components are appropriately exaggerated in some places in the accompanying drawings. Unless otherwise specified, the components in the drawings are not drawn to scale. The drawings of this application do not limit every dimension of each component. Moreover, the same figure numbers are used to represent the same components in all the drawings. In the drawings:

[0069] Figure 1 This is a schematic structural diagram of a solid-state battery cell according to one embodiment of the present application, which includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked in sequence.

[0070] Figure 2 Schematic diagram of a solid-state battery cell according to one embodiment of the present application.

[0071] Figure 3 for Figure 2 An exploded view of a solid-state battery cell according to an embodiment of the present application is shown.

[0072] Figure 4 This is a schematic diagram of a battery module according to one embodiment of the present application.

[0073] Figure 5 Schematic diagram of a battery pack according to one embodiment of the present application.

[0074] Figure 6 for Figure 5 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0075] Figure 7 Schematic diagram of an electrical device using a solid-state battery as a power source according to one embodiment of the present application.

[0076] Figure 8 The X-ray diffraction (XRD) diagrams of the sulfide solid electrolytes prepared in Example 8 and Comparative Example 3 of the present application, wherein the abscissa axis is 2θ (unit: degree, which can be expressed as °), and the ordinate axis is intensity.

[0077] 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

[0078] 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.

[0079] " scope " disclosed in the present application can be limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and any end value can be included or not included independently, and can be arbitrarily combined, that is, any lower limit can form a scope with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3,4 and 5 are also listed, then the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to listing the parameter as, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on. For example, when a parameter is expressed as an integer selected from "2-10", this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0080] In this application, unless otherwise specified, "about" means within a reasonable range above or below the number. The fluctuation range may vary depending on the type and value of the number. For example, a range of ±10%, ±5%, ±2%, ±1%, etc. may be allowed. For example, taking "about 20°C" and its approximate value of ±1°C as an example, approximate values ​​such as 19°C and 19.5°C within the approximate range of "about 20°C" should also be included in the range indicated by "about 20°C".

[0081] In this application, references to "multiple," "multiple," "multiple," "several," and the like, unless otherwise specified, refer to a quantity greater than or equal to two. For example, "one or more" means one or ≥ (greater than or equal to) two. It is understood that references to "any number" of items refer to any suitable combination of multiple items, i.e., any combination of "any number" of items that is not in conflict and that enables the implementation of this application.

[0082] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0083] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of such phrases in various locations in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. References to "implementations" herein have a similar understanding.

[0084] Those skilled in the art will appreciate that, in the methods of each embodiment or embodiment, the order in which each step is written does not mean a strict order of execution and constitutes any limitation to the implementation process, and the detailed order of execution of each step should be determined by its function and possible inherent logic. Unless otherwise specified, all steps of the present application can be performed in sequence, or can be performed randomly, or can preferably be performed in sequence. For example, method M includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, method M may also include step (c), indicating that step (c) can be added to method M in any order, for example, method M may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0085] In this application, in open technical features or technical solutions described with words such as "contain," "include," and "include," unless otherwise specified, additional members other than the listed members are not excluded, and it can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or not. It can be regarded as providing both the feature or solution of "A consists of a1, a2, and a3" or "A is selected from a1, a2, and a3", and the feature or solution of "A includes not only a1, a2, and a3, but also other members."

[0086] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0087] In this application, "optionally," "optional," and "optional" mean optional, that is, they refer to either option selected from the two parallel options of "yes" or "no." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" is independent. Unless otherwise specified, the descriptions "optionally include," "optionally include," etc. in this application, using "optionally include" as an example, mean "may include or not include."

[0088] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more relevant listed items, and also include any and all combinations of the relevant listed items, wherein any and all combinations include any two relevant listed items, any more relevant listed items, or a combination of all relevant listed items. For example, "A and / or B" means a group consisting of A, B, and "a combination of A and B." Among them, "including A and / or B" can mean "including A, including B, and including A and B", and can also mean "including A, including B, or including A and B", which can be appropriately understood according to the sentence in which it is used.

[0089] As used herein, "combination thereof", "any combination thereof", "any combination thereof" and the like include all suitable combinations of any two or more of the listed items.

[0090] Herein, the word “suitable” in “suitable combination”, “suitable method”, “any suitable method”, etc., shall be based on the technical solution that can implement the present application.

[0091] Herein, the terms "preferred," "better," "more preferable," "suitable," "comparatively better," and "preferable" are used solely to describe preferred implementations or examples and should not be construed as limiting the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, each "preferred" term is considered independent unless otherwise specified and there are no contradictions or mutual constraints.

[0092] In this application, "further", "further", "particularly", "for example", "such as", "example", "for example", etc. are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0093] In this application, the terms "first", "second", "third", "fourth", "fifth", "sixth", etc. in "first aspect", "second aspect", "third", "fourth", "fifth", "sixth", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", "fifth", "sixth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0094] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may refer to a relative horizontal positional relationship, or may simply refer to an attachment relationship without limiting the relative horizontal positional relationship.

[0095] In this application, the term "room temperature" generally refers to 4°C to 35°C, and may refer to 20°C ± 5°C. In some embodiments or examples of this application, room temperature refers to 20°C to 30°C.

[0096] In this application, when referring to a data range, if the unit is followed only by the right endpoint, it means that the units of the left and right endpoints are the same. For example, "3~5h" or "3-5h" both mean that the units of the left endpoint "3" and the right endpoint "5" are both hours, and both have the same meaning as "3h~5h". Similarly, descriptions of other parameters such as temperature and size are to be understood in the same manner.

[0097] The weight or mass of the relevant components mentioned in the embodiments or examples of the present application can not only refer to the content of each component, but also represent the proportional relationship of weight or mass between each component. Therefore, as long as the content of the relevant components in accordance with the embodiments or examples of the present application is proportionally enlarged or reduced, it is within the scope described in the present application. Further, the mass involved in the embodiments or examples of the present application can be mass units known to the chemical industry such as micrograms (μg), milligrams (mg), grams (g), kilograms (kg). Unless otherwise specified, the mass ratio is equal to the corresponding weight ratio, such as the mass of substance A is m1 and the weight is W1, the mass of substance B is m2 and the weight is W2, then the mass ratio m1 / m2 of the two is numerically equal to the corresponding weight ratio W1 / W2.

[0098] In this application, unless otherwise specified, wt% represents weight percentage by weight and is numerically equivalent to the corresponding mass percentage by mass. In this application, when a weight percentage is represented by "0", it has the same meaning as "0wt%" and can be used interchangeably.

[0099] The units of parameters involved in this application, unless otherwise specified, are nm for nanometers, μm for micrometers, S / cm for Siemens per centimeter, V for volts, kV for kilovolts, mA for milliamperes, Hz for Hertz, mPa·S for millipascals·seconds, and mg / cm 2 Expressed in milligrams per square centimeter, g / cm 2 Indicates grams per square centimeter, g / cm 3 represents grams per cubic centimeter and ℃ represents degrees Celsius.

[0100] In this application, "greater than or equal to", "greater than or equal to", and "≥" have the same meaning and can be used interchangeably; "less than or equal to", "less than or equal to", and "≤" have the same meaning and can be used interchangeably; "greater than" can be equivalently expressed as ">", and "less than" can be equivalently expressed as "<". In this application, unless otherwise specified, "greater than or equal to" and "≥" can be regarded as providing two solutions of "greater than" and "equal to". In this application, unless otherwise specified, "less than or equal to" and "≤" can be regarded as providing two solutions of "less than" and "equal to".

[0101] In this application, exemplary descriptions such as "in some embodiments (or examples)" and "in one embodiment (or example)" may include but are not limited to the following meanings: these solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0102] In this application, unless otherwise specified, the "solid-state battery" provided in this application refers to a battery in which the electrolyte in the battery includes a solid electrolyte; generally, a solid-state battery includes a positive electrode layer, a solid electrolyte layer and a negative electrode layer. During the charge and discharge process of the battery, active ions are embedded and released back and forth between the positive electrode layer and the negative electrode layer. The solid electrolyte layer plays the role of conducting ions between the positive electrode layer and the negative electrode layer, and can also isolate the positive electrode layer from the negative electrode layer to prevent the positive and negative electrodes from short-circuiting. Therefore, the isolation membrane in the traditional lithium-ion battery can be omitted in the solid-state battery. The solid-state battery introduces a non-flammable solid electrolyte to replace the organic electrolyte in the traditional liquid lithium-ion battery, which greatly improves the safety of the battery. In addition to improving safety, solid-state batteries can better adapt to high-energy-density positive and negative electrode materials and reduce the weight of the system, which is conducive to taking into account the improvement of energy density.

[0103] In this application, unless otherwise specified, "solid electrolyte" refers to an electrolyte material or substance that exists in a solid form during the storage and preparation of a solid-state battery and its components, as well as during the operation of the solid-state battery. It is understood that the solid electrolyte exists in a solid form, including but not limited to, at room temperature.

[0104] In this application, unless otherwise specified, an electrode layer may be a positive electrode layer or a negative electrode layer, and the electrode layer includes an electrode active material. The electrode active material may be a positive electrode active material or a negative electrode active material. The electrode active material may be a particle itself or contained in electrode active particles. The electrode active particles may be positive electrode active particles or negative electrode active particles. The "electrode active material" in the electrode layer refers to a substance capable of reversibly inserting and removing active ions. Unless otherwise specified, "negative electrode active material" refers to a substance used in the negative electrode layer that is capable of reversibly inserting and removing active ions; "positive electrode active material" refers to a substance used in the positive electrode layer that is capable of reversibly removing and inserting active ions. When a solid-state battery is charging, active ions are removed from the positive electrode and inserted into the negative electrode through the solid electrolyte layer; when the solid-state battery is discharging, active ions are removed from the negative electrode and inserted into the positive electrode. The active ions are not particularly limited and are non-restrictive. The active ions can be lithium ions, in which case the battery corresponds to a lithium-ion solid-state battery.

[0105] In the present application, "electrode active particles" refer to particles containing an electrode active material.

[0106] In this application, "electrode active material", "electrode active substance", "active material" and "active substance" have the same meaning and can be used interchangeably; "positive electrode active substance" and "positive electrode active material" have the same meaning and can be used interchangeably; "negative electrode active substance" and "negative electrode active material" have the same meaning and can be used interchangeably. "Positive electrode active substance" and "positive electrode active material" have the same meaning and can be used interchangeably; "negative electrode active substance" and "negative electrode active material" have the same meaning and can be used interchangeably.

[0107] In this application, unless otherwise specified, the term "electrode active material layer" includes at least one of the positive electrode active material layer in the positive electrode layer and the negative electrode active material layer in the negative electrode layer. Depending on the specific circumstances, the electrode active material layer may refer to the positive electrode active material layer or the negative electrode active material layer. It is understood that the positive electrode active material layer contains a positive electrode active substance, and the negative electrode active material layer contains a negative electrode active substance. In this application, the term "electrode active material layer" may also be referred to as the "active material layer."

[0108] In the present application, unless otherwise specified, the positive electrode layer at least includes a positive electrode active material layer.

[0109] In the present application, unless otherwise specified, the positive electrode active material layer includes at least positive electrode active particles and generally also includes positive electrode electrolyte particles.

[0110] In this application, unless otherwise specified, “positive electrode active particles” refer to particles containing positive electrode active materials, which have the ability to reversibly release and embed active ions.

[0111] In this application, unless otherwise specified, "positive electrode electrolyte particles" and "positive electrode solid electrolyte" have the same meaning and can be used interchangeably to refer to solid electrolytes that can be used in positive electrode membranes or positive electrode layers. Positive electrode electrolyte particles can enhance the ion conductivity of the positive electrode membrane or positive electrode layer and reduce interfacial impedance, thereby promoting the charge transfer efficiency between the positive electrode active material and the outside world and fully releasing its capacity.

[0112] In the present application, unless otherwise specified, the negative electrode layer at least includes a negative electrode active material layer.

[0113] In the present application, unless otherwise specified, the negative electrode active material layer at least includes negative electrode active particles, and may or may not include negative electrode electrolyte particles.

[0114] In this application, unless otherwise specified, “negative electrode active particles” refer to particles containing negative electrode active materials, which have the ability to reversibly embed and de-embed active ions.

[0115] In this application, unless otherwise specified, "negative electrode electrolyte particles" and "negative electrode solid electrolyte" have the same meaning and can be used interchangeably to refer to solid electrolytes that can be used in negative electrode films or negative electrode layers. Negative electrode electrolyte particles can enhance the ion conductivity of the negative electrode film or negative electrode layer and reduce interfacial impedance, thereby promoting the charge transfer efficiency between the negative electrode active material and the outside world and fully releasing its capacity.

[0116] In solid-state batteries, the interface contact and interface stability issues are one of the pain points that limit their performance, and poor interface contact will affect the cycle performance of the battery. Due to the "solid-solid contact" characteristics existing in solid-state batteries, the contact between the particles inside 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, resulting in insufficient interface ion transport within the electrode layer, which in turn leads to unsatisfactory performance of the solid-state battery. By doping solid electrolyte materials into the electrode layer, it is theoretically possible to enhance the ion conductivity of the electrode layer, promote the charge transfer efficiency between the electrode active material and the outside world and the full release of its capacity, and reduce impedance. Among the many solid electrolyte materials, sulfide solid electrolytes have a high ionic conductivity (about 10 -3 ~10 -2 S / cm) and excellent mechanical properties, such as good flexibility, which give it excellent ion conductivity and good deformation ability, making it a solid electrolyte material with the most practical and industrial prospects.

[0117] Argentite-type sulfide solid electrolytes containing Li, P, S, and Cl are typically sintered using precursor materials including Li2S, P2S5, and LiCl. This sintering process typically results in sulfur (S) loss, which can easily lead to the inclusion of impurities such as LiCl in the sintered product. The presence of impurities can hinder ion transport in the argyrodite-type sulfide solid electrolyte, resulting in suboptimal ionic conductivity.

[0118] When there is an excess of Cl in the argyrodite-type sulfide solid electrolyte, the S content decreases more significantly as S is lost during sintering. The high content of impurities such as LiCl will seriously hinder ion transport, resulting in a significant decrease in the ionic conductivity of the solid electrolyte material.

[0119] This application provides a sulfide solid electrolyte and its preparation method, a solid electrolyte membrane, an electrode plate, a solid-state battery, and an electrical device. It also provides a positive electrode membrane, a negative electrode membrane, and a secondary battery. The sulfide solid electrolyte has high ionic conductivity and can effectively improve the rate performance of secondary batteries or solid-state batteries.

[0120] In a first aspect of the present application, a sulfide solid electrolyte is provided, which includes an argyrodite-type crystal phase.

[0121] In some embodiments, the argyrodite-type crystal phase includes Li, P, S, M, and T; 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.

[0122] In some embodiments, in the argyrodite-type crystal phase, the atomic number ratio of the T element to the P element is 1+x, and x>0.

[0123] 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.

[0124] In some embodiments, a sulfide solid electrolyte is provided, comprising an argyrodite-type crystal phase;

[0125] The argyrodite-type crystal phase includes Li, P, S, M, and T; 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.

[0126] In the argyrodite-type crystal phase, the atomic ratio of the T element to the P element is 1+x, and x>0;

[0127] 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.

[0128] In this application, unless otherwise specified, "sulfide electrolyte" and "sulfide solid electrolyte" have the same meaning and can be used interchangeably, referring to a solid electrolyte in the form of sulfide, wherein the sulfide electrolyte includes sulfur (S) in the form of sulfide. The "sulfide electrolyte" involved in the embodiments or examples of this application can be in any of the solid electrolyte layer, the positive electrode layer, and the negative electrode layer, and can be contained in the electrolyte material of the solid electrolyte layer, in the positive electrode electrolyte particles, or in the negative electrode electrolyte particles.

[0129] In this application, unless otherwise specified, "argyrodite-type crystal phase" refers to a crystal structure identical or similar to that of the sulfide solid electrolyte Li6PS5Cl, belonging to the cubic crystal system, and the argyrodite-type crystal phase corresponds to the argyrodite-type sulfide solid electrolyte; "argyrodite-type sulfide solid electrolyte" refers to a sulfide solid electrolyte having a crystal structure identical or similar to that of the sulfide solid electrolyte Li6PS5Cl.

[0130] In the sulfide solid electrolyte provided in the present application, the T element is excessive ((1+x)>1, that is, x>0) in the crystal structure of the argyrodite-type crystal phase, and the M element is introduced to compensate for the S loss.

[0131] In this application, unless otherwise specified, "atomic number ratio" refers to the number ratio of specified elements or atoms, which can be measured in moles, in which case it corresponds to "atomic molar ratio".

[0132] In this application, unless otherwise specified, whether the sulfide solid electrolyte includes an argyrodite-type crystal phase can be determined based on the X-ray diffraction (XRD) pattern. In this application, unless otherwise specified, the X-ray diffraction pattern of the sulfide solid electrolyte is obtained using a powder sample using Cu Kα radiation. Typically, the 2θ (°) scanning range includes at least 10° to 50° (the scanning range may include 10° to 80°), and the 2θ (°) scanning speed can be 0.02° / second. In some embodiments, the XRD test instrument and parameters are as follows: Bruker-D8 advance, using Cu target Kα1 radiation, wavelength λ is 0.15406nm, X-ray tube controlled at 40kV and 40mA, 2θ (°) scanning range is 10° to 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 an argyrodite-type crystal phase by comparing it with the standard XRD spectrum of Li6PS5Cl. In some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte has peaks at 14.6°, 17.4°, 20.2°, 20.5°, 24.0°, 26.9°, 29.5°, 32.6°, 36.5°, 41.5°, and 47.3° near the following group of 2θ (°) diffraction angles. Due to differences in measurement factors such as the measuring instrument and measurement conditions, the position of a peak or peaks in the actual X-ray diffraction pattern may be slightly offset (e.g., ±δ°). However, it is understandable that those skilled in the art can identify as a whole whether "an X-ray diffraction pattern including slightly different characteristic peaks substantially constitutes an argyrodite-type crystal phase." Unless otherwise specified, "±δ°" only represents the error in the diffraction angle position of the peak and has nothing to do with the peak shape or peak width of the peak. In terms of numerical values, regarding the aforementioned peak position shift ±δ°, δ can be 0.4, 0.3, 0.2, 0.1, etc. according to measurement conditions. For example, in some embodiments, δ=0.2.

[0133] In the present application, unless otherwise specified, the types of elements and the atomic ratios of the elements in the sulfide solid electrolyte can be determined by elemental analysis methods such as inductively coupled plasma spectrometry (ICP method), thereby determining the chemical formula.

[0134] The sulfide solid electrolyte provided in the first aspect of the present application is a thiogermanate sulfide solid electrolyte including a thiogermanate crystal phase, and the thiogermanate crystal phase contains Li element, P element, S element, and T element (T element is one or both of Cl element and Br element); when the atomic number ratio (1 + x) of T element to P element is greater than 1 (at this time x > 0), by introducing M element (selectable from one or both of Se element and Te element), on the one hand, the excessive T element can generate more lithium vacancies; on the other hand, by using the smaller Coulomb binding force of T element on lithium ions, it can promote the easier migration of lithium ions, which is beneficial 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 sulfur (S) loss during the sintering process of the sulfide raw material, inhibit the formation of impurity phases such as LiT, and is also beneficial 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 broaden the ion transport channels in the crystal structure. The above-mentioned multiple synergistic effects can significantly improve the ionic conductivity of the thiogermanate sulfide solid electrolyte.

[0135] When this sulfide solid electrolyte is used as the solid electrolyte material in a secondary battery or a solid-state battery, it can be used as the solid electrolyte material in one or more structural layers such as the solid electrolyte layer, the positive electrode layer, and the negative electrode layer, which can effectively reduce the resistance of the solid-state battery, improve the rate performance of the secondary battery or the solid-state battery, and enable the secondary battery or the solid-state battery to have better electrochemical performance at high rates.

[0136] When this sulfide solid electrolyte is used as the positive electrode electrolyte particles in the positive electrode layer, it can also promote the capacity utilization of the positive electrode active material in the positive electrode layer.

[0137] When this sulfide solid electrolyte is used as the positive electrode electrolyte particles in the negative electrode layer, it can also promote the capacity utilization of the positive electrode active material in the negative electrode layer.

[0138] In some embodiments, in the thiogermanate crystal phase, 0 < x ≤ 0.8. Without limitation, x can also be any one of the following values, greater than 0 and less than or equal to any one of the following values, or selected from the intervals formed by any two of the following values: 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, etc.

[0139] By controlling x within the above range, the T element can be controlled within a more optimal range, which is beneficial to better improving the ionic conductivity of the sulfide solid electrolyte, and at the same time, the content of impurity phases can be controlled at a lower ratio.

[0140] In some embodiments, in the argyrodite crystal phase, 0 < y ≤ 0.1. Without limitation, y can also be any one of the following values, greater than 0 and less than or equal to any one of the following values, or selected from the intervals formed by 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.

[0141] By controlling y within the foregoing range, the M element can be controlled within a more optimal range, which is more conducive to suppressing the impurity phase and improving the ionic conductivity of the sulfide solid electrolyte.

[0142] In some embodiments, in the argyrodite 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), where 0 < x ≤ 0.8 and 0 < y ≤ 0.1. Among them, x and y can be combined in a suitable manner. x and y can also refer to any suitable values or ranges in the context respectively.

[0143] In some embodiments, the chemical formula of the argyrodite crystal phase is Li 6-x PS 5-x-y M y T 1+x .

[0144] When the argyrodite crystal phase has the foregoing chemical formula, it is conducive to better suppressing the impurity phase and better improving the ionic conductivity of the sulfide solid electrolyte.

[0145] In some embodiments, the chemical formula of the argyrodite crystal phase is Li 6-x PS 5-x-y Se y Cl 1+x .

[0146] When the M element includes the Se element and the T element includes the Cl element, it is conducive to the sulfide solid electrolyte having more excellent ionic conductivity.

[0147] In some embodiments, the argyrodite crystal phase satisfies one or more of the following characteristics (any numerical parameter in the following characteristics can also be selected from any suitable values or ranges in the context):

[0148] In the argyrodite 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;

[0149] In the argyrodite crystal phase, 0 < y ≤ 0.1; Optionally, 0.02 ≤ y ≤ 0.1; Further optionally, 0.02 ≤ y ≤ 0.09.

[0150] In some embodiments, 0.3≤x≤0.8, 0.02≤y≤0.09.

[0151] By controlling one or both of the parameters x and y within the aforementioned ranges, the contents of the T and M elements can be adjusted to more appropriate levels, which is beneficial for improving the ionic conductivity of the sulfide solid electrolyte. Specifically, by controlling y within the aforementioned range, the M element can be controlled within an even more optimal range, further facilitating the suppression of impurities and improving the ionic conductivity of the sulfide solid electrolyte.

[0152] In the present application, in the argyrodite-type crystal phase, the atomic number ratio of the S element to the P element can be expressed as 5-xy.

[0153] In some embodiments, 4.1≤(5-xy)<5.0. Without limitation, 5-xy 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 an 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.

[0154] In some embodiments, 4.1<(5-xy)<4.7.

[0155] When the atomic number ratio of the S element to the P element (5-xy) is controlled within the aforementioned range, controlling the contents of x and y is more conducive to suppressing the impurity phase and improving the ionic conductivity of the sulfide solid electrolyte.

[0156] In some embodiments, in the argyrodite-type crystal phase, the T element includes a Cl element.

[0157] In some embodiments, in the argyrodite-type crystal phase, the M element includes Se.

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

[0159] When the M element includes Se, it is beneficial for the sulfide solid electrolyte to have better ionic conductivity.

[0160] When the T element includes the Cl element, it is beneficial for the sulfide solid electrolyte to have better ionic conductivity.

[0161] In this application, the atomic ratio of Cl and Br in the argyrodite crystal phase can be expressed as R Cl / Br .

[0162] Without limitation, R Cl / BrIt can be (0~1):(0~1), 1:(0~1), or (0~1):1

[0163] In this application, the atomic ratio of Se and Te in the argyrodite crystal phase can be expressed as R Se / Te .

[0164] Without limitation, R Se / Te It can be (0~1):(0~1), can be 1:(0~1), and can also be (0~1):1.

[0165] About R Cl / Br and R Se / Te In any of the above ratios, the value in the range of 0 to 1 can be any of the following values, or an 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.

[0166] In some embodiments, the argyrodite-type crystal phase satisfies one or two of the following characteristics (any numerical parameter in the following characteristics may also be selected from any appropriate numerical value or range in the context):

[0167] 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;

[0168] 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.

[0169] 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.

[0170] 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 He Li 5.5 PS 4.44 Se 0.06 Cl 1.5.

[0171] By providing one or more aforementioned argyrodite-type crystal phases in the sulfide solid electrolyte, it is more advantageous to reduce impurity phases and improve ionic conductivity.

[0172] In some embodiments, 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. The definition and identification method of the "argyrodite-type crystal phase" can be found in the above text.

[0173] 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°, where δ can be found in the above text; optionally, δ is 0.2 or 0.1.

[0174] In some embodiments, the sulfide solid electrolyte has a 2θ (°) diffraction angle in an X-ray diffraction pattern having 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°.

[0175] The relative content of the impurity phase can be determined by comparing the intensity of the main diffraction peak (strongest diffraction peak) of the argyrodite-type crystal phase with the intensity of the impurity phase diffraction peak in the XRD pattern.

[0176] In some embodiments, 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° in the X-ray diffraction pattern, indicating that the impurity content is extremely low. The peak near 34.9° corresponds to the 2θ diffraction peak of LiCl.

[0177] In some embodiments, there is no LiT heterophase peak in the X-ray diffraction pattern of the sulfide solid electrolyte.

[0178] In some embodiments, no obvious diffraction peaks of impurity phases such as LiT are observed in the X-ray diffraction pattern of the sulfide solid electrolyte.

[0179] In some embodiments, the mass proportion of the argyrodite-type crystal phase in the sulfide solid electrolyte can be greater than 85wt%, and can also be greater than any of the following percentages, or greater than or equal to any of the following percentages, or selected from the interval consisting of any one of the following percentages and 100wt%, or selected from the interval consisting of any two of the following percentages: 90wt%, 92wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, etc.

[0180] In some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα radiation, and in some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte is obtained by using Cu Kα1 radiation.

[0181] In some embodiments, the X-ray diffraction pattern of the sulfide solid electrolyte is obtained by powder X-ray diffraction testing.

[0182] In some embodiments, the sulfide solid electrolyte satisfies at least one of the following characteristics:

[0183] 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°, where δ is 0.2 or 0.1;

[0184] There is no LiT impurity phase peak in the X-ray diffraction pattern of the sulfide solid electrolyte;

[0185] 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°;

[0186] The X-ray diffraction pattern of the sulfide solid electrolyte was obtained by using Cu Kα radiation;

[0187] The X-ray diffraction pattern of the sulfide solid electrolyte was obtained by powder X-ray diffraction test.

[0188] The chemical composition and amount of impurities in sulfide solid electrolytes can be confirmed by X-ray diffraction (XRD) detection.

[0189] In a second aspect of the present application, a method for preparing 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.

[0190] In some embodiments, the method for preparing a sulfide solid electrolyte comprises the following steps:

[0191] S100: providing a precursor mixture including Li2S, P2S5, an optional sulfur element, M element, and LiT according to a desired raw material stoichiometric ratio; wherein M element is selected from one or both of Se element and Te element, T is a halogen, and LiT is selected from one or both of LiCl element and LiBr element;

[0192] S200: sintering the precursor mixture in an inert atmosphere to prepare a sulfide solid electrolyte including an argyrodite-type crystal phase;

[0193] 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. In some embodiments, the argyrodite-type crystal phase satisfies x>0 and y>0.

[0194] In this application, unless otherwise specified, the phrase "providing raw materials in a desired stoichiometric ratio" in step S100 refers to providing the raw materials in the desired stoichiometric ratio to obtain the target chemical formula. Once the target chemical formula is determined, those skilled in the art will be able to select appropriate precursor raw materials and a suitable stoichiometric ratio.

[0195] In the present application, unless otherwise specified, “M element” refers to Se element, Te element, or a combination of Se element and Te element.

[0196] In some embodiments, the M element includes Se element, and may further be Se element.

[0197] In some embodiments, the M element includes Te element, and may further be Te element.

[0198] In some embodiments, in the step of sintering the precursor mixture in an inert atmosphere, the sintering temperature may be 450° C. to 530° C.

[0199] Without limitation, in step S200, the sintering temperature can be 450°C to 530°C, or any two of the following temperatures or a range consisting of any two of the following temperatures: 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, etc.

[0200] Without limitation, in step S200 , the inert atmosphere may be an argon atmosphere.

[0201] 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 this application.

[0202] In a third aspect of the present application, a solid electrolyte membrane is provided, 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.

[0203] Without limitation, the solid electrolyte membrane may be an independent solid electrolyte membrane sheet, which is then used to assemble a solid-state battery; the solid electrolyte membrane may also be a solid electrolyte membrane layer present in a composite structure.

[0204] The solid electrolyte membrane can be prepared using conventional methods in the field of solid-state batteries, such as pressing the solid electrolyte material into a membrane.

[0205] In some embodiments, the solid electrolyte membrane is an all-solid-state electrolyte membrane.

[0206] In this application, unless otherwise specified, "all-solid-state electrolyte membrane" refers to a solid electrolyte membrane whose constituent materials are all solid.

[0207] In another aspect of the present application, a solid electrolyte membrane is provided, which 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.

[0208] In another aspect of the present application, a positive electrode film is provided, which includes a positive electrode active material layer, and the positive 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.

[0209] Without limitation, the positive electrode film can be a standalone positive electrode film sheet or a positive electrode sheet, which can be used to assemble a solid-state battery. The positive electrode film can also be a positive electrode film layer present in a multi-layer composite structure. For example, the constituent materials of the positive electrode film layer can be pressed into a film on the surface of a solid electrolyte layer. As a non-limiting example, the positive electrode film can be a positive electrode layer or a portion of a positive electrode layer of a solid-state battery.

[0210] In some embodiments, the negative electrode film is an all-solid-state positive electrode film.

[0211] In this application, unless otherwise specified, "all-solid-state cathode film" refers to a cathode film whose constituent materials are all solid.

[0212] In another aspect of the present application, a positive electrode membrane is provided, which includes a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector, and the positive 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.

[0213] In another aspect of the present application, a negative electrode membrane is provided, which includes a negative electrode active material layer, and the negative 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.

[0214] Without limitation, the negative electrode film can be a standalone negative electrode film sheet or negative electrode sheet, which can be used to assemble a solid-state battery. The negative electrode film can also be a negative electrode film layer present in a multi-layer composite structure. For example, the constituent materials of the negative electrode film layer can be pressed into a film on the surface of a solid electrolyte layer. As a non-limiting example, the negative electrode film can be a negative electrode layer or a portion of a negative electrode layer of a solid-state battery.

[0215] In some embodiments, the negative electrode film is an all-solid-state negative electrode film.

[0216] In this application, unless otherwise specified, "all-solid-state anode film" refers to an anode film whose constituent materials are all solid.

[0217] In another aspect of the present application, a negative electrode membrane is provided, which includes a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector, and the negative electrode active material layer 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.

[0218] For a solid electrolyte membrane, positive electrode membrane or negative electrode membrane provided with the aforementioned sulfide solid electrolyte, the resistance can be effectively reduced, and the corresponding secondary battery or solid-state battery can be given better rate performance, so that the secondary battery or solid-state battery can have better electrochemical performance at high rates.

[0219] When the sulfide solid electrolyte is used as 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.

[0220] 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.

[0221] In the fourth aspect of the present application, an electrode plate is provided, which includes an electrode active material layer, the electrode active material layer includes an electrode active substance, and the electrode active material layer also 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.

[0222] In some embodiments, the electrode plate is a positive electrode plate, 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;

[0223] 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.

[0224] In this application, unless otherwise specified, the electrode plate includes an electrode active material layer. As previously described, the electrode active material layer includes an electrode active substance. In the electrode plate, the electrode active substance may itself constitute particulate matter or may be contained in electrode active particles. Unless otherwise specified, the electrode active material layer in the electrode plate provided in this aspect also includes a sulfide solid electrolyte. Furthermore, the electrode active material layer includes at least one of the sulfide solid electrolyte described in the first aspect of this application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of this application.

[0225] In some embodiments, the electrode active material layer includes electrode active particles, and the electrode active material layer also includes at least one of the sulfide solid electrolyte described in the first aspect of this application and the sulfide solid electrolyte prepared by the preparation method described in the second aspect of this application. The electrode plate can be a positive electrode plate, and the electrode active particles are positive electrode active particles. In this case, a positive electrode plate is provided, which includes a positive electrode active material layer, and the positive electrode active material layer includes positive electrode active particles and the aforementioned sulfide solid electrolyte. The electrode plate can also be a negative electrode plate, and the electrode active particles are negative electrode active particles. In this case, a negative electrode plate is provided, which includes a negative electrode active material layer, and the negative electrode active material layer includes negative electrode active particles and the aforementioned sulfide solid electrolyte.

[0226] For electrode plates provided with the aforementioned sulfide solid electrolyte, the internal resistance of the plates can be reduced, the capacity of the active material in the plates can be promoted, and the corresponding secondary batteries or solid-state batteries can be given better rate performance.

[0227] The electrode plate can be a positive electrode plate or a negative electrode plate.

[0228] In another aspect of the present application, a secondary battery is provided, which includes 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 membrane described in the third aspect of the present application, the aforementioned positive electrode membrane, the aforementioned negative electrode membrane and at least one of the electrode plates described in the fourth aspect of the present application.

[0229] In the present application, unless otherwise specified, the "secondary battery" provided above in the present application includes a positive electrode sheet, a negative electrode sheet, and a solid electrolyte layer located between the positive electrode sheet and the negative electrode sheet.

[0230] In this application, unless otherwise specified, a "positive electrode sheet" includes a positive electrode active material layer. In some embodiments, the positive electrode sheet in the secondary battery is the aforementioned positive electrode film.

[0231] In this application, unless otherwise specified, the "negative electrode sheet" includes the negative electrode active material layer. In some embodiments, the negative electrode sheet in the secondary battery is the aforementioned negative electrode film.

[0232] In this application, unless otherwise specified, the "solid electrolyte layer" includes a solid electrolyte. In some embodiments, the solid electrolyte layer is a solid electrolyte membrane layer composed of the solid electrolyte membrane described in the third aspect of this application.

[0233] When a secondary battery is charged, active ions are released from the positive electrode and embedded in the negative electrode through the solid electrolyte layer. When the secondary battery is discharged, active ions are released from the negative electrode and embedded in the positive electrode. The active ions are not specifically limited and can be lithium ions, in which case it corresponds to a lithium-ion secondary battery.

[0234] In the fifth aspect of the present application, a solid-state battery is provided, which includes 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 membrane described in the third aspect of the present application, the aforementioned positive electrode membrane, the aforementioned negative electrode membrane and at least one of the electrode plates described in the fourth aspect of the present application.

[0235] In some embodiments, the solid-state battery includes at least one of the sulfide solid electrolyte described in the first aspect of this application, the sulfide solid electrolyte prepared by the preparation method described in the second aspect of this application, the solid electrolyte membrane described in the third aspect of this application, and the electrode plate described in the fourth aspect of this application.

[0236] In some embodiments, the positive electrode layer in the solid-state battery includes the aforementioned positive electrode film, and may further be the aforementioned positive electrode film.

[0237] In some embodiments, the negative electrode layer in the solid-state battery includes the aforementioned negative electrode film, and may further be the aforementioned negative electrode film.

[0238] In some embodiments, the solid electrolyte layer in the solid-state battery includes the solid electrolyte membrane described in the third aspect of the present application, and may further be the solid electrolyte membrane described in the third aspect of the present application.

[0239] In some embodiments, the solid-state battery is a sulfide all-solid-state battery.

[0240] The "solid-state battery" provided in the fifth aspect of the present application 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. Therefore, it is a sulfide solid-state battery.

[0241] In this application, unless otherwise specified, a "sulfide solid-state battery" refers to a solid-state battery in which the electrolyte involved in the battery includes a sulfide solid electrolyte. The sulfide solid electrolyte can be located in at least one of the positive electrode layer, negative electrode layer, and solid electrolyte layer of the sulfide solid-state battery. The sulfide solid-state battery can further be an all-solid-state battery.

[0242] In this application, unless otherwise specified, "all-solid-state battery" refers to a solid-state battery in which the electrolytes in the battery are all solid electrolytes. In this case, the positive electrode layer, the negative electrode layer and the electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery, so it can be called an "all-solid-state battery".

[0243] In this application, unless otherwise specified, a "solid-state battery" in any embodiment or example may be, but is not limited to, a sulfide all-solid-state battery. Unless otherwise specified, a "sulfide all-solid-state battery" refers to an all-solid-state battery in which the electrolyte involved in the battery includes a sulfide solid electrolyte. The sulfide solid electrolyte may be located in at least one of the positive electrode layer, negative electrode layer, and solid electrolyte layer of the sulfide all-solid-state battery.

[0244] The types of solid electrolytes present in different membrane layers of a secondary battery or 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.

[0245] In the secondary battery or solid-state battery provided by 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.

[0246] In a secondary battery or solid-state battery provided with the aforementioned sulfide solid electrolyte, the sulfide solid electrolyte may be provided in one or more of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer.

[0247] As a non-limiting example, the positive electrode electrolyte particles, the negative electrode electrolyte particles and the solid electrolyte in the solid electrolyte layer can each independently include solid electrolyte materials that are well known in the art and can be used for solid-state batteries. For example, they can each independently include one or more of the following materials: one or more of sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, polymer solid electrolytes, etc.

[0248] In the sixth aspect of the present application, an electrical device is provided, which includes 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 membrane described in the third aspect of the present application, the aforementioned positive electrode membrane, the aforementioned negative electrode membrane, the electrode plate described in the fourth aspect of the present application, the aforementioned secondary battery and at least one of the solid-state battery described in the fifth aspect of the present application.

[0249] In some embodiments, the electrical device includes at least one of the sulfide solid electrolyte described in the first aspect of this application, the sulfide solid electrolyte prepared by the preparation method described in the second aspect of this application, the solid electrolyte membrane described in the third aspect of this application, the electrode plate described in the fourth aspect of this application, and the solid-state battery described in the fifth aspect of this application.

[0250] The following is some description about the solid electrolyte layer.

[0251] The solid electrolyte layer plays the role of conducting ions between the positive electrode layer and the negative electrode layer, and can also isolate the positive electrode layer and the negative electrode layer to prevent the positive and negative electrodes from short-circuiting.

[0252] It is understood that the solid electrolyte layer includes a solid electrolyte. The solid electrolyte in the solid electrolyte layer can be a solid electrolyte material known in the art that can be used for solid-state batteries.

[0253] In some embodiments, the solid electrolyte layer comprises the sulfide solid electrolyte described in the first aspect of the present application.

[0254] In some embodiments, the solid electrolyte layer may be pressed from a solid electrolyte material into a solid electrolyte membrane, which may be a solid electrolyte membrane sheet or a solid electrolyte membrane layer.

[0255] In some embodiments, the thickness of the solid electrolyte layer may be 0.1 μm to 1000 μm, and may be optionally 10 μm to 100 μm, 100 μm to 800 μm, 500 μm to 800 μm, or the like.

[0256] The following is some description about the positive electrode film and the positive electrode layer.

[0257] In this application, unless otherwise specified, "positive electrode film" refers to a film that can be used as a positive electrode of a solid-state battery, including at least a positive electrode active material layer and usually also a positive electrode current collector.

[0258] The positive electrode layer can be provided by a positive electrode sheet or positive electrode membrane that can be used in solid-state batteries in the art. Alternatively, the constituent materials of the positive electrode layer can be directly pressed onto one surface of the solid electrolyte layer to form a positive electrode membrane layer. The positive electrode membrane can be combined with other films suitable for the positive electrode to form a positive electrode sheet or positive electrode layer.

[0259] The positive electrode layer can be prepared by a dry process or a wet process. For example, a dry process can be used to press a positive electrode film, which can be a positive electrode film sheet or a positive electrode film layer. For another example, a wet process can be used to coat a positive electrode film, which can be a positive electrode film layer.

[0260] In some embodiments, the positive electrode film includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The definition of the positive electrode active material layer can be found in the above text.

[0261] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. In the positive electrode current collector, the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. In the positive electrode current collector, the composite current collector may be obtained by forming a metal material on a polymer material substrate. In the positive electrode current collector, non-limiting examples of the metal material may include one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. In the positive electrode current collector, non-limiting examples of the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0262] Without limitation, in the positive electrode film or positive electrode layer, the thickness of the positive electrode active material layer is 30μm to 400μm, optionally 60μm to 130μm, and can also be any of the following thicknesses or an interval consisting of any two of the following thicknesses: 30μm, 40μm, 50μm, 60μm, 80μm, 100μm, 120μm, 130μm, 140μm, 150μm, 160μm, 180μm, 200μm, etc.

[0263] In this application, unless otherwise specified, the "thickness of the positive electrode active material layer" refers to the total thickness of the positive electrode film or positive electrode layer. When the positive electrode active material layer is provided on both sides of the positive electrode current collector, the thickness of the positive electrode active material layer refers to the sum of the thicknesses on both sides.

[0264] As a non-limiting example, the positive electrode current collector has two surfaces facing away from each other in its thickness direction, and the positive electrode active material layer is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0265] The positive electrode film and the positive electrode layer each include a positive electrode active material layer. The positive electrode active material layer includes positive electrode active particles containing a positive electrode active material.

[0266] Without limitation, the weight percentage of the positive electrode active particles or the positive electrode active substance in the positive electrode active material layer can be ≥70wt%, further ≥80wt%, further ≥90wt%, and can also be any of the following weight percentages or an interval consisting of any two of the following weight percentages: 70wt%, 75wt%, 80wt%, 82wt%, 84wt%, 85wt%, 86wt%, 88wt%, 90wt%, 92wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, etc.

[0267] In some embodiments, the positive electrode active material layer includes positive electrode electrolyte particles. Without limitation, the weight proportion of the positive electrode electrolyte particles in the positive electrode active material layer can be 0.1wt% to 30wt%, optionally 5wt% to 20wt%, and the weight proportion of the positive electrode electrolyte particles in the positive electrode active material layer can also be any of the following weight percentages or a range selected from any two of the following weight percentages: 0.1wt%, 0.2wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.8wt%, 1wt%, 1 .2wt%, 1.5wt%, 1.6wt%, 1.8wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 12wt%, 14wt%, 15wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 25wt%, 26wt%, 28wt%, 30wt%, etc.

[0268] In some embodiments, the positive electrode active material layer includes positive electrode active particles and positive electrode electrolyte particles.

[0269] In some embodiments, the positive electrode active material in the positive electrode active particles can be a battery-use positive electrode active material known in the art. As non-limiting examples, the positive electrode active material can 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 can be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxide, 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.

[0270] Taking a solid-state battery in which active ions include lithium ions as an example, it is understandable that the solid-state battery will be accompanied by the deintercalation and consumption of lithium (Li) during the charge and discharge process, and the content of Li in the positive electrode layer is different when the battery is discharged to different states. In the exemplary description of the positive electrode active material in this application, unless otherwise specified, the content of Li can be the initial state of the material or the non-initial state after the charge and discharge cycle. The positive electrode active material is applied to the positive electrode layer in the solid-state battery system. After the charge and discharge cycle, the content of Li in the positive electrode active material contained in the positive electrode layer usually changes. Among them, the content of Li can be measured using atomic molar content, but is not limited to this. Regarding "the content of Li is the initial state of the material", the initial state of the material refers to the state before being placed in the positive electrode layer. It can be understood that new materials or new substances obtained by appropriate modification on the basis of the listed positive electrode active materials are also within the scope of positive electrode active materials. The aforementioned appropriate modification refers to an acceptable modification method for the positive electrode active material, and a non-limiting example is coating modification. In the exemplary descriptions of the positive electrode active material in this application, the oxygen (O) content is generally a theoretical value. Lattice oxygen release will cause the atomic molar content of oxygen to change, and the actual O content will fluctuate. The O content can be measured by atomic molar content, but is not limited to this.

[0271] In some embodiments, the positive electrode active material layer includes a conductive agent (which may be referred to as a positive electrode conductive agent). As a non-limiting example, the positive electrode conductive agent may be a carbon conductive agent. Non-limitingly, the carbon conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers. In some embodiments, the positive electrode conductive agent may include but is not limited to one or more of SP, KS-6, acetylene black, Ketjen black ECP with a branched structure, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs) and graphene. Non-limitingly, the weight percentage of the positive electrode conductive agent in the positive electrode active material layer may be 0 to 10 wt%, further 0 to 8 wt%, further 0 to 5 wt%, further 0.1 wt% to 3 wt%, based on the total weight of the positive electrode active material layer. The weight percentage of the positive electrode conductive agent in the positive electrode active material layer may also be 0.1 wt% to 5 wt%, 0.2 wt% to 5 wt%, 0.5 wt% to 5 wt%, 0.1 wt% to 3 wt%, etc.

[0272] In some embodiments, the positive electrode active material layer optionally includes a binder (which may be referred to as a positive electrode binder). As a non-limiting example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin. Typically, the weight percentage of the positive electrode binder in the positive electrode active material layer may be 0 to 10 wt%, further 0 to 8 wt%, further 0.1 wt% to 5 wt%, further 1 wt% to 5 wt%, based on the total weight of the positive electrode active material layer.

[0273] Without limitation, the positive electrode active material layer may include positive electrode active particles, positive electrode electrolyte particles, a positive electrode conductive agent, and a positive electrode binder. The type and content of each component can be referred to the context of this application.

[0274] In some embodiments, the positive electrode electrolyte particles include the sulfide solid electrolyte described in the first aspect of the present application.

[0275] In some embodiments, a positive electrode membrane (a positive electrode membrane can be used as a positive electrode sheet) can be prepared in the following manner: the components for preparing the positive electrode membrane, such as positive electrode active particles, positive electrode electrolyte particles, positive electrode conductive agent, optional positive electrode binder and any other components are dry-mixed, and then the mixed material is heated, pressurized and kneaded into a mass material, which is hot rolled to form a self-supporting positive electrode sheet, and the self-supporting positive electrode sheet is hot-rolled with the positive electrode collector. The self-supporting positive electrode sheet can be compounded on at least one side (one side or two sides) of the positive electrode collector to obtain a positive electrode membrane. Without limitation, a double planetary mixer can be used for dry mixing. Without limitation, an internal mixer can be used for heating, pressurizing and kneading. Without limitation, the temperature for hot rolling can be 75°C to 85°C, further such as 78°C, 80°C, 82°C, etc. The method of assembling solid-state batteries using positive electrode membranes can be suitable for industrial mass production. A similar method can be used to prepare negative electrode membranes or negative electrode sheets.

[0276] In some embodiments, the positive electrode membrane can be prepared by the following method: the components for preparing the positive electrode membrane, such as positive electrode active particles, positive electrode electrolyte particles, positive electrode conductive agent, positive electrode binder and any other components, are dispersed in an organic solvent to form a positive electrode slurry. Further, the positive electrode slurry is coated on at least one side of the positive electrode current collector, and after drying, pressing and other processes, the positive electrode membrane can be obtained. The type of organic solvent in the positive electrode slurry can include one or more of p-xylene, trimethylbenzene, butyl butyrate, heptane, etc., and can further 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) based on dry weight (excluding solvent) can be 15mg / cm 2 ~35mg / cm 2 The compaction density of the positive electrode membrane can be 3.0g / cm 3 ~3.6g / cm 3 , optional 3.3g / cm 3 ~3.5g / cm 3 .

[0277] The “compacted density” used in this application has a meaning well known in the art and is one of the reference indicators of material energy density. In this application, unless otherwise specified, the compacted density of an electrode layer refers to the ratio of the mass of the electrode active material layer to its volume. The compacted density of a positive electrode layer, a positive electrode sheet, a positive electrode film or a positive electrode membrane refers to the ratio of the mass of the positive electrode active material layer to its volume, and the compacted density of a negative electrode layer, a negative electrode sheet, a negative electrode film or a negative electrode membrane refers to the ratio of the mass of the negative electrode active material layer to its volume.

[0278] Compacted density = coating area density / thickness of electrode active material layer.

[0279] Coating area density = slurry dry weight / electrode active material layer area.

[0280] The double-sided thickness of the electrode active material layer corresponds to the sum of the coating surface density on both sides, and the single-sided thickness corresponds to the single-sided coating surface density; when the electrode active material layers on both sides of the current collector are basically the same, it can be calculated according to the following formula: compaction density = single-sided coating surface density / single-sided thickness of the electrode active material layer.

[0281] The “single-sided” and “double-sided” electrode active material layers refer to the positional distribution relative to the current collector.

[0282] The following is some description about the negative electrode film and negative electrode layer.

[0283] In this application, unless otherwise specified, "negative electrode film" refers to a film that can be used as a negative electrode of a solid-state battery, including at least a negative electrode active material layer and may also include a negative electrode current collector.

[0284] The negative electrode layer can be provided by a negative electrode sheet or negative electrode membrane that can be used in solid-state batteries in the art. Alternatively, the negative electrode layer component materials can be directly pressed onto one surface of the solid electrolyte layer to form a negative electrode membrane layer. The negative electrode membrane can be combined with other films suitable for the negative electrode to form a negative electrode sheet or negative electrode layer.

[0285] The negative electrode layer can be prepared by a dry process or a wet process. For example, a dry process can be used to press the negative electrode film, which can be a negative electrode film sheet or a negative electrode film layer. For another example, a wet process can be used to coat the negative electrode film, which can be a negative electrode film layer.

[0286] The negative electrode film and the negative electrode layer each include a negative electrode active material layer, which includes negative electrode active particles containing negative electrode active materials. Without limitation, the negative electrode active material layer may include or exclude negative electrode electrolyte particles.

[0287] In some embodiments, the negative electrode active material layer includes negative electrode electrolyte particles. Further, the negative electrode electrolyte particles may include the sulfide solid electrolyte described in the first aspect of the present application.

[0288] Without limitation, the weight percentage of the negative electrode active particles or the negative electrode active material in the negative electrode active material layer may be ≥80 wt %, and further may be ≥90 wt %.

[0289] In some embodiments, the negative electrode active particles or the negative electrode active material are lithium-indium alloy (InLi alloy).

[0290] In some embodiments, the negative electrode layer is an InLi alloy film.

[0291] In some embodiments, the negative electrode active material may also be a negative electrode active material that is well known in the art and can be used for solid-state batteries. As a non-limiting example, the negative electrode active material may include one or more of the following materials: elemental silicon, elemental tin, silicon-carbon anode, silicon monoxide, graphite, and metallic lithium. However, the present application is not limited to these materials or substances, and other traditional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0292] In some embodiments, the negative electrode sheet or negative electrode film may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material. As a non-limiting example, the negative electrode current collector has two surfaces that face away from each other in the thickness direction of the negative electrode current collector, and the negative electrode active material layer is disposed on either or both of the two facing surfaces of the negative electrode current collector. In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. In the negative electrode current collector, the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. In the negative electrode current collector, the composite current collector may be formed by forming a metal material on a polymer material base layer. Non-limiting examples of the metal material in the negative electrode current collector may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. In the negative electrode current collector, non-limiting examples of the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), and the like.

[0293] In some embodiments, the negative electrode active material layer may optionally include a conductive agent, referred to as a negative electrode conductive agent. Without limitation, the negative electrode conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In the negative electrode active material layer, the weight percentage of the negative electrode conductive agent may be 0 to 10 wt %, further preferably 0 to 5 wt %, further preferably 0.1 wt % to 5 wt %, and further preferably 0.1 wt % to 3 wt %.

[0294] In some embodiments, the negative electrode active material layer may optionally include a binder (referred to as a negative electrode binder). As a non-limiting example, the negative electrode binder may 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 acrylate resin. In a non-limiting manner, the weight proportion of the negative electrode binder in the negative electrode active material layer may be 0 to 10 wt %, further 0 to 5 wt %, further 1 wt % to 5 wt %, and further optionally 1 wt % to 3 wt %.

[0295] In some embodiments, the negative electrode active material layer may optionally include other additives, such as a thickener (e.g., sodium carboxymethyl cellulose (CMC-Na)). The weight percentage of the other additives in the negative electrode active material layer may be 0-15 wt %, further preferably 0-10 wt %, further preferably 0-5 wt %, further preferably 0-3 wt %, and further preferably 0-2 wt %.

[0296] In some embodiments, the negative electrode membrane (the negative electrode membrane can be used as the negative electrode sheet) can be prepared in the following manner: the components for preparing the negative electrode membrane, such as negative electrode active particles, optional negative electrode electrolyte particles, negative electrode conductive agent, optional negative electrode binder and any other components are dry-mixed, and then the mixed material is heated, pressurized and kneaded into a mass material, and hot roller pressed to form a self-supporting negative electrode sheet, and the self-supporting negative electrode sheet is hot-rolled with the negative electrode collector. The self-supporting negative electrode sheet can be compounded on at least one side (one side or two sides) of the negative electrode collector to obtain a negative electrode membrane. Without limitation, a double planetary mixer can be used for dry mixing. Without limitation, an internal mixer can be used for heating, pressurizing and kneading. The method of assembling solid-state batteries using negative electrode membranes can be suitable for industrial mass production. When the negative electrode material is prepared into a negative electrode active material layer by a dry method, a negative electrode conductive agent can be set in the negative electrode material to improve the electron conductivity of the negative electrode active material layer.

[0297] In some embodiments, a negative electrode sheet or negative electrode membrane can be prepared by dispersing the components used to prepare the negative electrode sheet or negative electrode membrane, such as negative electrode active particles, optional negative electrode electrolyte particles, negative electrode conductive agent, negative electrode binder, and any other components, in a solvent (a non-limiting example of a solvent is p-xylene) to form a negative electrode slurry. Furthermore, the negative electrode slurry is coated on at least one surface of a negative electrode current collector. After drying and pressing, the negative electrode sheet or negative electrode membrane can be obtained. The negative electrode current collector surface coated with the negative electrode slurry can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 30 wt% to 70 wt%, preferably 40 wt% to 60 wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000 mPa·s to 10000 mPa·s, preferably 3000 mPa·s to 10000 mPa·s. When coating the negative electrode slurry, the coating unit area density (single side) based on dry weight (excluding solvent) can be 1.5 mg / cm 2 ~18mg / cm 2 , but not limited thereto. The compaction density of the negative electrode sheet or negative electrode membrane can be 1.0 g / cm 3 ~2.0g / cm 3 , optional 1.0g / cm 3 ~1.8g / cm 3 .

[0298] In a non-limiting manner, the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet can be stacked in sequence, the solid electrolyte can be placed between the positive electrode membrane and the negative electrode membrane, and the solid-state battery cell can be prepared by hot rolling.

[0299] In a non-limiting manner, the positive electrode membrane, the solid electrolyte membrane and the negative electrode membrane may be stacked in sequence, the solid electrolyte may be placed between the positive electrode membrane and the negative electrode membrane, and the solid-state battery cell may be prepared by hot rolling.

[0300] In some embodiments, the solid-state battery cell 5 includes a solid-state battery cell 52 .

[0301] In some embodiments, the solid-state battery cell is an all-solid-state battery cell.

[0302] In some embodiments, the solid-state battery cell 52 (which may be an all-solid-state battery cell) includes a positive electrode layer 200, a solid electrolyte layer 100, and a negative electrode layer 300 stacked in sequence. An example of this can be found in Figure 1 .

[0303] In some embodiments, the solid-state battery may include an outer packaging that can be used to encapsulate the solid-state battery cell.

[0304] In some embodiments, the outer packaging of the solid-state battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the solid-state battery can also be a soft package, such as a bag-type soft package. The material of the soft package can be plastic. Further, non-limiting examples of plastic can include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0305] The present application has no particular restrictions on the shape of the solid-state battery cell, which can be cylindrical, square or any other shape. For example, Figure 2 The solid-state battery cell 5 is a square structure as an example.

[0306] In some embodiments, reference Figure 3 The outer packaging may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The solid-state battery cell 52 is encapsulated in the receiving cavity. The number of solid-state battery cells 52 contained in the solid-state battery cell 5 can be one or more, and those skilled in the art can select according to actual needs.

[0307] The solid-state battery can be a battery module 4 or a battery pack 1 .

[0308] The battery module includes at least one solid-state battery cell. The number of solid-state battery cells contained in the battery module can be one or more, and those skilled in the art can select an appropriate number based on the application and capacity of the battery module.

[0309] Figure 4 4 is an example of a battery module. Figure 4 In the battery module 4, the plurality of solid-state battery cells 5 may be arranged in sequence along the length of the battery module 4. Of course, they may also be arranged in any other manner. The plurality of solid-state battery cells 5 may further be fixed by fasteners.

[0310] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of solid-state battery cells 5 are received in the receiving space.

[0311] In some embodiments, the battery modules may be assembled into a battery pack. The battery pack may contain one or more battery modules. Those skilled in the art may select an appropriate number based on the application and capacity of the battery pack.

[0312] Figure 5 and Figure 6 The battery pack 1 is used as an example. Figure 5 and Figure 6 The battery pack 1 may include a battery box and multiple battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner in the battery box.

[0313] In some embodiments, the electrical device includes the solid-state battery of any embodiment provided herein.

[0314] Without limitation, solid-state batteries can be used as power sources for electrical devices or as energy storage units for electrical devices. Electrical devices may include, but are not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, and the like. Examples of mobile devices include, but are not limited to, mobile phones and laptops; examples of electric vehicles include, but are not limited to, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric motorcycles, and electric tools. The electrical device may also be used in fields such as military equipment and aerospace, and in energy storage power systems such as hydropower, thermal power, wind power, and solar power stations.

[0315] As an electrical device, a solid-state battery can be selected according to its usage requirements.

[0316] Figure 7The example of an electric device 6 is shown. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the electric device's requirements for high power and high energy density of solid-state batteries, a battery pack or battery module can be used.

[0317] Another example device may be a mobile phone, a tablet computer, a laptop computer, etc. Such a device is usually required to be lightweight and thin, and may use a solid-state battery as a power source.

[0318] Below, some embodiments of the present application are described. The embodiment described below is exemplary, is only used to explain the present application, and cannot be construed as limiting the present application. In the embodiment, if no technology or conditions are indicated, it is carried out according to the description above, or according to the technology or conditions described in the document in this area, or according to the product specification. Reagents used or instruments that do not indicate manufacturers are conventional products that can be obtained commercially, or can be synthesized in a conventional manner by commercially available products.

[0319] In the following examples, room temperature refers to 20°C to 30°C.

[0320] In the following examples, unless otherwise specified, the amount of "M element (such as Se element, Te element or a combination of the two)" expressed in wt% refers to the weight percentage in the sintered mixture. In the following examples, unless otherwise specified, the sintered mixture is the precursor mixture.

[0321] It should be noted that sulfide all-solid-state batteries are used as non-limiting examples of solid-state batteries in the following embodiments and examples.

[0322] In the following examples, unless otherwise specified, the positive electrode active particles NCM 811 Powder D v 50 is 4μm (positive electrode active material is NCM 811 ), D of Li6PS5Cl sulfide electrolyte v 50 is 1μm.

[0323] In this application, unless otherwise stated, D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%.

[0324] D v 50 tests:

[0325] In the following examples and comparative examples, the D v50 The following method was used for testing and confirmation: Equipment model: Malvern 2000 (MasterSizer 2000) laser particle size analyzer, reference standard process: GB / T19077-2016 / ISO 13320:2009, specific test process: take an appropriate amount of the sample to be tested (the sample concentration is guaranteed to be 8%-12% (w / v) shading), add 20mL of p-xylene (when testing sulfide solid electrolytes, a dispersant ammonium polycarboxylate is also added), and at the same time, ultraviolet light is applied for 5min (53KHz / 120W) to ensure that the sample is completely dispersed, and then the sample is measured according to GB / T19077-2016 / ISO13320:2009 standard.

[0326] 1. Preparation of sulfide solid electrolytes, solid electrolyte membranes, and all-solid-state batteries

[0327] (1) Preparation of sulfide solid electrolyte

[0328] The target chemical formula is Li 6-x PS 5-x-y M y T 1+x As shown in Table 1, the M element is one or both of Se and Te, and the T element is one or both of Cl and Br.

[0329] Example 1. M element is Se element, T element is Cl element, and the target chemical formula is Li 5.7 PS 4.68 Se 0.02 T 1.3 .

[0330] According to the stoichiometric ratio of raw materials Li 5.7 PS 4.7 Cl 1.3 2.2 mol Li2S, 0.5 mol P2S5 and 1.3 mol LiCl raw material powders were weighed respectively, and 3 wt% of selenium was weighed and mixed to obtain a precursor mixture. The above precursor mixture was placed in an atmosphere (argon) furnace and sintered at 530°C for 8 h, and then the sintered body was crushed to obtain argyrodite-type sulfide solid electrolyte powder.

[0331] 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).

[0332] Sulfide solid electrolytes were prepared using a method substantially identical to that of Example 1, except that the amount of selenium added was changed to 6 wt % (Example 2) and 10 wt % (Example 3), respectively. The remaining steps were identical to those of Example 1.

[0333] Example 4. The target chemical formula is Li 5.95 PS 4.9 Se 0.05 Cl 1.05 .

[0334] The sulfide solid electrolyte was prepared by the same method as in Example 1, except that the stoichiometric ratio of the raw materials of Li, P, S and Cl was Li 5.95 PS 4.95 Cl 1.05 , the amount of Se added is 6wt%.

[0335] Example 5. The target chemical formula is Li 5.9 PS 4.85 Te 0.05 Br 1.1 .

[0336] The sulfide solid electrolyte was prepared by the same method as in Example 1, except that the stoichiometric ratio of the raw materials of Li, P, S and Br was Li 5.9 PS 4.9 Br 1.1 , Se elemental substance was replaced by Te elemental substance, and the addition amount of Te elemental substance was 6 wt%.

[0337] Example 6. The target chemical formula is Li 5.9 PS 4.87 Se 0.02 Te 0.01 Cl 0.6 Br 0.5 .

[0338] The sulfide solid electrolyte was prepared by the same method as in Example 1, except that the stoichiometric ratio of the raw materials of Li, P, S, Cl and Br was Li 5.9 PS 4.9 Cl 0.6 Br 0.5 , the addition amount of Se element is 3wt%, and the addition amount of Te element is 2wt%.

[0339] Example 7. The target chemical formula is Li 5.95 PS 4.85 Se 0.1 Cl 1.05 .

[0340] The sulfide solid electrolyte was prepared by the same method as in Example 1, except that the stoichiometric ratio of the raw materials of Li, P, S and Cl was Li 5.95 PS 4.95 Cl 1.05 , the amount of Se added is 12wt%.

[0341] Example 8. The target chemical formula is Li 5.5 PS 4.47 Se 0.03 Cl 1.5 .

[0342] According to the stoichiometric ratio of raw materials Li 5.5 PS 4.5 Cl 1.5 2.0 mol Li2S, 0.5 mol P2S5 and 1.5 mol LiCl raw material powders were weighed respectively, and 4 wt% of selenium was weighed and mixed to obtain a precursor mixture. The above precursor mixture was placed in an atmosphere (argon) furnace and sintered at 500°C for 8 hours, and then the sintered body was crushed to obtain argyrodite-type sulfide solid electrolyte powder.

[0343] Example 9-10. The target chemical formula is 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).

[0344] Except that the addition amount of selenium was changed to 7 wt % and 10 wt % respectively, the remaining steps of Examples 9-10 were the same as those of Example 8.

[0345] Example 11. The target chemical formula is Li 5.2 PS 4.17 Se 0.03 Cl 1.8 .

[0346] According to the stoichiometric ratio of raw materials Li 5.2 PS 4.2 Cl 1.8 1.7 mol Li2S, 0.5 mol P2S5 and 1.8 mol LiCl raw material powders were weighed respectively, and 4 wt% of selenium was weighed and mixed to obtain a precursor mixture. The above precursor mixture was placed in an atmosphere (argon) furnace and sintered at 480°C for 8 hours, and then the sintered body was crushed to obtain argyrodite-type sulfide solid electrolyte powder.

[0347] 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).

[0348] Except that the addition amount of elemental selenium was changed to 7 wt % and 10 wt % respectively, the remaining steps of Examples 12-13 were the same as those of Example 11.

[0349] Example 14. The target chemical formula is Li 5.2 PS 4.1 Se 0.1 Cl 1.8 .

[0350] Except that the addition amount of elemental selenium is changed to 12 wt %, the remaining steps of Example 14 are the same as those of Example 11.

[0351] 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 .

[0352] The sulfide solid electrolyte was prepared by the same method as in Example 11, except that the stoichiometric ratio of the raw materials of Li, P, S and Cl was Li 5.2 PS 4.2 Cl 1.5 Br 0.3 , except that the addition amount of Se elemental substance is changed to 9wt% and the addition amount of Te elemental substance is changed to 3wt% respectively, the remaining steps of Example 15 are the same as those of Example 11.

[0353] Comparative Example 1. The target chemical formula is Li6PS5Cl 1.3 .

[0354] According to the raw material stoichiometric ratio of Li6PS5Cl, 2.5 mol of Li2S, 0.5 mol of P2S5 and 1 mol of LiCl raw material powders were weighed and mixed to obtain a raw material mixture. The above raw material mixture was placed in an atmosphere (argon) furnace and sintered at 550°C for 8 hours. The sintered body was then crushed to obtain argyrodite-type sulfide solid electrolyte powder.

[0355] Comparative Example 2. The target chemical formula is Li 5.7 PS 4.7 Cl 1.3 .

[0356] 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 powders were weighed respectively and mixed to obtain a raw material mixture. The raw material mixture was placed in an atmosphere (argon) furnace and sintered at 530°C for 8 h. The sintered body was then crushed to obtain argyrodite-type sulfide solid electrolyte powder.

[0357] Comparative Example 3. The target chemical formula is Li 5.5 PS 4.5 Cl 1.5 .

[0358] According to the stoichiometric ratio of raw materials Li 5.5 PS 4.5 Cl 1.5 2.0 mol of Li2S, 0.5 mol of P2S5 and 1.5 mol of LiCl raw material powders were weighed respectively and mixed to obtain a raw material mixture. The raw material mixture was placed in an atmosphere (argon) furnace and sintered at 500°C for 8 h. The sintered body was then crushed to obtain argyrodite-type sulfide solid electrolyte powder.

[0359] Comparative Example 4. The target chemical formula is Li 5.2 PS 4.2 Cl 1.8 .

[0360] According to the stoichiometric ratio of raw materials Li 5.2 PS 4.2 Cl 1.8 1.7 mol of Li2S, 0.5 mol of P2S5 and 1.8 mol of LiCl raw material powders were weighed respectively and mixed to obtain a raw material mixture. The raw material mixture was placed in an atmosphere (argon) furnace and sintered at 480°C for 8 h. The sintered body was then crushed to obtain argyrodite-type sulfide solid electrolyte powder.

[0361] (2) Preparation of solid electrolyte membranes (solid electrolyte membrane form) and all-solid-state batteries

[0362] Examples 1-15 correspond to the sulfide solid electrolyte powders prepared in step (1) of Examples 1-15, respectively:

[0363] In an argon atmosphere, the sulfide solid electrolyte powder (prepared in Example 1-15) was pressed into a dense solid electrolyte membrane at 360 MPa.

[0364] In an argon atmosphere, NCM 811The powder, sulfide solid electrolyte Li6PS5Cl, conductive carbon fiber (VGCF) and binder PTFE were weighed in a weight ratio of 85:13:1:1, mixed evenly in a double planetary mixer, and then the evenly mixed powder was heated and pressurized in an internal mixer to form a mass material, and then hot-rolled at 80°C to form a self-supporting positive electrode sheet, and then hot-rolled with the current collector Al foil to obtain a positive electrode sheet (positive electrode membrane).

[0365] The positive electrode sheet is placed on one side of a solid electrolyte membrane, and an InLi alloy is stacked on the other side of the solid electrolyte membrane as the negative electrode layer to assemble an all-solid-state battery. In this case, the solid electrolyte membrane serves as the solid electrolyte layer, and the positive electrode sheet serves as the positive electrode layer. The battery test window is 2.6-4.3V vs. Li.

[0366] Comparative Examples 1-4:

[0367] A method substantially the same as that of Example 1 was used, except that the sulfide solid electrolyte powder used to prepare the solid electrolyte membrane was replaced by the sulfide solid electrolyte powder prepared in Comparative Examples 1-4.

[0368] Table 1. Target chemical formula of sulfide solid electrolytes 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) can be found in Table 1.

[0369] Table 1. Chemical formula information and M element addition amount information of the sulfide solid electrolytes prepared in Examples 1-15 and Comparative Examples 1-4.

[0370]

[0371]

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

[0373] 2. Preparation of a positive electrode layer provided with a sulfide solid electrolyte and a solid-state battery (all-solid-state secondary battery, sulfide all-solid-state battery) provided in this application.

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

[0375] In an argon atmosphere, the positive electrode active particles NCM 811 The raw materials, namely, sulfide solid electrolyte powder (prepared in 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 evenly in a double planetary mixer, and then the evenly mixed powder was heated and pressurized in an internal mixer to form a mass-like material, which was then hot-rolled at 80°C to form a self-supporting positive electrode sheet, which was then hot-rolled with the current collector Al foil to obtain a positive electrode sheet (positive electrode membrane).

[0376] In an argon atmosphere, the sulfide solid electrolyte powder Li6PS5Cl was pressed into a dense solid electrolyte membrane under 360MPa.

[0377] The positive electrode sheet is placed on one side of a solid electrolyte membrane, and an InLi alloy is stacked on the other side of the solid electrolyte membrane as the negative electrode layer to assemble an all-solid-state battery. In this case, the solid electrolyte membrane serves as the solid electrolyte layer, and the positive electrode sheet serves as the positive electrode layer. The battery test window is 2.6-4.3V vs. Li.

[0378] Comparative Example P1.

[0379] An all-solid-state battery was prepared using a method substantially the same as that of Example P8, except that the cathode electrolyte particles in the composite cathode powder were replaced with Li6PS5Cl in Comparative Example 1.

[0380] 3. Preparation of a negative electrode layer provided with a sulfide solid electrolyte and a solid-state battery (all-solid-state secondary battery, sulfide all-solid-state battery) provided in this application.

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

[0382] In an argon atmosphere, the sulfide solid electrolyte powder Li6PS5Cl was pressed into a dense solid electrolyte membrane under 360MPa.

[0383] In an argon atmosphere, NCM 811 The raw materials, Li6PS5Cl sulfide solid electrolyte, conductive carbon fiber (VGCF), and PTFE binder, were weighed in a weight ratio of 85:13:1:1 and manually ground in a mortar until uniformly mixed to obtain a composite cathode powder. The composite cathode powder was evenly spread on one side of a solid electrolyte membrane and cold-pressed into a sheet at 420 MPa for 5 minutes, forming a composite membrane consisting of a cathode layer and a solid electrolyte layer.

[0384] In an argon atmosphere, the negative electrode active particles Si powder, sulfide solid electrolyte powder (prepared in Example 1-15, as the negative electrode electrolyte particles) and the negative electrode binder PVDF were dispersed in a solvent p-xylene (solid content 60 wt%) at a weight ratio of 80:17:3. The coating density was 2.5 mg / cm2 based on the dry weight (excluding the solvent). 2 Coated on the other side of the solid electrolyte layer in the composite membrane and dried to form a negative electrode layer, a sulfide all-solid-state battery is obtained, which includes a positive electrode layer (corresponding to the positive electrode membrane), a solid electrolyte layer (corresponding to the solid electrolyte membrane) and a negative electrode layer (corresponding to the negative electrode membrane) stacked in sequence.

[0385] Comparative Example N1.

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

[0387] 4. Material testing and analysis

[0388] (1) Testing and analysis methods

[0389] 1. Elemental analysis

[0390] The element types and proportions of the sulfide solid electrolyte were analyzed using an inductively coupled plasma spectrometer (ICP instrument) to determine its chemical formula.

[0391] Test instrument: ThermoFisher ICAP Pro.

[0392] 2. Crystal phase analysis

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

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

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

[0396] Analysis method: Confirm whether the sulfide solid electrolyte to be tested includes argyrodite-type crystal phase by comparing with the standard XRD spectrum of Li6PS5Cl.

[0397] 3. Ionic conductivity test

[0398] The ionic conductivity was measured by electrochemical impedance spectroscopy (EIS).

[0399] Sample to be tested: sulfide solid electrolyte powder.

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

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

[0402]

[0403] Where d is the thickness of the solid electrolyte membrane, and A is the contact area between the electrolyte sheet and the current collector.

[0404] 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 found in Table 2 "Ionic Conductivity".

[0405] 4. First discharge capacity

[0406] Testing method: The assembled all-solid-state battery was charged at a current density of 0.1C to 3.68V (4.3V vs. lithium), allowed to rest for 10 minutes, and then discharged at a current density of 0.1C to 2.18V (2.8V vs. lithium) to obtain the battery's initial discharge capacity. The battery was tested at 25±3°C, with 1C = 200mA / g. The test results can be found in Table 3.

[0407] 5. Rate performance

[0408] Test method: The all-solid-state batteries were charged at a fixed rate of 0.1C. Discharges were then performed at rates of 0.1C, 0.33C, 1C, 2C, and 3C, with three cycles at each rate. The battery voltage window was 2.8–4.3V vs. Li+ / Li. The batteries were tested at 25±3°C, with 1C = 200mA / g. The test results are shown in Table 3.

[0409] (2) Test results analysis

[0410] 1. Elemental analysis

[0411] The ICP test confirmed that the chemical formula of the sulfide solid electrolytes prepared in Examples 1-15 and Comparative Examples 1-4 is basically 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 composition are: the atomic number ratio of Li:P:S:Se:Cl is = 5.51:1.02:4.40:0.03:1.49.

[0412] 2. According to the XRD analysis results, the sulfide solid electrolytes prepared in Examples 1-15 and Comparative Examples 1-4 all formed an argyrodite-type crystal phase. In addition, the impurity content in the argyrodite-type sulfide solid electrolytes of each example is relatively low. See Table 2. As an example, the X-ray diffraction (XRD) patterns of the sulfide solid electrolytes prepared in Example 8 and Comparative Example 3 can be seen in Figure 8 .

[0413] 3. Ionic conductivity

[0414] The test results of hydrogen sulfide release and ion conductivity of the sulfide solid electrolytes prepared in Examples 1-15 and Comparative Examples 1-4 can be found in Table 2.

[0415] Compared with Comparative Example 1, the sulfide solid electrolyte Li 6-x PS 5-x-y M y T 1+x All satisfy x>0 and y>0. Compared to Comparative Example 1, the sulfide solid electrolytes prepared in Examples 1-15 all have higher ionic conductivity. The sulfide solid electrolytes prepared in Examples 1-2 compared to Comparative Example 2, Examples 8-10 compared to Comparative Example 3, and Examples 11-14 compared to Comparative Example 4 all have significantly reduced hydrogen sulfide release and good ionic conductivity. See Table 2 for details.

[0416] 4. Battery performance

[0417] Compared to Comparative Example 1, the solid-state batteries of Examples 1-15 all exhibited better initial discharge capacity and rate performance. Furthermore, compared to Comparative Example 2, Examples 8-10 compared to Comparative Example 3, and Examples 11-14 compared to Comparative Example 4, the solid-state batteries produced all exhibited lower impurity content and higher ionic conductivity. See Table 3 for details.

[0418] As an example, compared to Example P8, the positive electrode layer of Comparative Example P1 does not contain the sulfide solid electrolyte provided by the first aspect of the present application, and both the initial discharge capacity and rate performance are significantly deteriorated. See Table 3.

[0419] As an example, compared to Example N2, the negative electrode layer of Comparative Example N1 does not contain the sulfide solid electrolyte provided by the first aspect of the present application, and the initial discharge capacity and rate performance are significantly deteriorated. See Table 3.

[0420] The solid-state batteries of Examples 1-15 all use the sulfide solid electrolyte described in the first aspect of this application in the solid electrolyte layer, which effectively reduces the resistance of the solid-state battery. The solid-state battery has excellent rate performance and can achieve better electrochemical performance at high rates.

[0421] Examples P1-P15 use the sulfide solid electrolyte described in the first aspect of the present application as positive electrode electrolyte particles in the positive electrode layer, which not only reduces the internal resistance of the electrode sheet, but also promotes the capacity of the positive electrode active material in the positive electrode layer.

[0422] Examples N1-N15 use the sulfide solid electrolyte described in the first aspect of the present application as negative electrode electrolyte particles in the negative electrode layer, which not only reduces the internal resistance of the electrode sheet, but also promotes the capacity of the positive electrode active material in the negative electrode layer.

[0423] Table 2.

[0424]

[0425] Table 3.

[0426]

[0427] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referenced and will not be repeated here for the sake of brevity. The technical features of the embodiments described above can be combined in any way. To keep the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0428] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and within the scope of the technical solution of the present application, embodiments that have substantially the same structure as the technical idea and exert the same effect are all included in the technical scope of the present application. The embodiments described above only express several embodiments of the present application, and the description thereof is relatively detailed, but it cannot be understood as limiting the scope of the patent. In addition, without departing from the scope of the subject matter of the present application, other methods of applying various modifications that can be thought of by those skilled in the art to the embodiments and combining some of the constituent elements in the embodiments to construct the embodiments are also included in the scope of the present application.

Claims

1. A sulfide solid electrolyte, characterized in that: Including argyrodite type crystal phase; The argyrodite-type crystal phase includes Li, P, S, M and T elements; 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, characterized in that In the argyrodite-type crystal phase, 0 <x≤0.8。 3. The sulfide solid electrolyte according to claim 1 or 2, characterized in that In the argyrodite-type crystal phase, 0 <y≤0.1。 4. The sulfide solid electrolyte according to any one of claims 1 to 3, characterized in that 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, characterized in that 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, characterized in that 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 5, characterized in that 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 5, characterized in that 0.3≤x≤0.8, 0.02≤y≤0.

09.

9. The sulfide solid electrolyte according to any one of claims 1 to 5, characterized in that 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, characterized in that 4.1<(5-xy)<4.

7.

11. The sulfide solid electrolyte according to any one of claims 1 to 10, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that Meet 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, characterized in that: It includes the following steps: Providing a precursor mixture comprising Li2S, P2S5, an optional sulfur element, M element, and LiT according to a desired raw material stoichiometric ratio; wherein the M element is selected from one or both of Se element and Te element, T is a halogen, and LiT is selected from one or both of LiCl element and LiBr element; 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, wherein: Meet 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, characterized in that The invention 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.

19. An electrode plate, characterized in that: The invention comprises an electrode active material layer, wherein the electrode active material layer comprises an electrode active substance and 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, characterized in that: 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, characterized in that: The invention comprises 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 plate according to claim 19 or 20.

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

23. An electrical device, characterized in that: The invention comprises 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 sheet according to claim 19 or 20, and the solid-state battery according to claim 21 or 22.

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