Solid-state battery and preparation method therefor, positive electrode sheet, and electric device

Abstract

A solid-state battery and a preparation method therefor, a positive electrode sheet, and an electric device. The solid-state battery comprises a positive electrode layer, the positive electrode layer comprises a positive electrode active material layer, and the positive electrode active material layer comprises a positive electrode active material and a solid electrolyte, which are mixed with each other. The solid electrolyte comprises an oxyhalide solid electrolyte, the oxyhalide solid electrolyte contains an M element, and the M element comprises one or more of Zr, Fe, Al and Cr. The molar ratio of the halogen and oxygen contained in the oxyhalide solid electrolyte is m / b, wherein m is an absolute value of the valence of the M element in the oxyhalide solid electrolyte, and 0<b≤3.

Description

Solid-state batteries, their preparation methods, positive electrode plates, and electrical devices thereof

[0001] This application claims priority to Chinese patent application filed on February 27, 2025, application number 202510227795.8, entitled "Solid-state battery and method for preparation thereof, positive electrode sheet and electrical device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of solid-state battery technology, and further to solid-state batteries and their preparation methods, positive electrode sheets, and electrical devices. Background Technology

[0003] Solid-state batteries use non-flammable solid electrolytes instead of the organic electrolytes in traditional liquid secondary batteries, significantly improving battery safety and are considered the next generation of batteries closest to industrialization. Solid electrolyte materials are the key materials determining the performance of all-solid-state batteries. However, solid-state batteries using traditional solid electrolyte materials suffer from poor cycle performance. Summary of the Invention

[0004] In view of the above problems, this application provides a solid-state battery, a method for its fabrication, a positive electrode, and an electrical device thereof. This solid-state battery exhibits excellent cycle performance.

[0005] The first aspect of this application provides a solid-state battery, including a positive electrode layer, the positive electrode layer including a positive electrode active material layer, the positive electrode active material layer comprising a mixture of positive electrode active materials and a solid electrolyte, the solid electrolyte including a halide oxide solid electrolyte, the halide oxide solid electrolyte containing an element M, the element M including one or more of Zr, Fe, Al and Cr, the molar ratio of halogen and oxygen elements contained in the halide oxide solid electrolyte being m / b, wherein m is the absolute value of the valence of the element M in the halide oxide solid electrolyte, 0 < b ≤ 3.

[0006] Therefore, by introducing a halide oxide solid electrolyte into the positive electrode active material layer, the ionic conductivity of the composite positive electrode can be significantly improved, thus enhancing the performance of solid-state batteries. Simultaneously, by controlling the molar ratio of halogens to oxygen in the halide oxide solid electrolyte, the amorphization degree of the halide oxide solid electrolyte can be effectively improved, thereby reducing stress concentration at the interface between the halide oxide solid electrolyte and the positive electrode active material, resulting in higher interfacial stability and further improving the cycle stability of solid-state batteries. Furthermore, halide oxide solid electrolytes do not contain rare or precious metals, significantly reducing their production cost.

[0007] In any embodiment of this application, the chemical formula of the halide oxide solid electrolyte is Li. a MX m O b Wherein, element X includes one or more of F, Cl and Br, 0 < a ≤ 6, 0 < b ≤ 3, and m is the absolute value of the oxidation state of element M in the halide oxide solid electrolyte.

[0008] In any embodiment of this application, the Dv50 of the halide oxide solid electrolyte is less than or equal to the Dv50 of the positive electrode active material. This, on the one hand, helps to increase the contact sites between halide oxide solid electrolyte particles, forming better ion transport channels; on the other hand, it can increase the contact area between the halide oxide solid electrolyte and the positive electrode active material, improving the cycle stability of the solid-state battery.

[0009] In any embodiment of this application, the Dv50 of the halide oxide solid electrolyte is 1 μm-3 μm. This results in more contact sites between the halide oxide solid electrolyte particles, forming better ion transport channels.

[0010] In any embodiment of this application, the halide oxide solid electrolyte accounts for 5%-35% of the mass of the positive electrode active material layer. This allows for the construction of good electron / ion transport channels in the positive electrode layer, reducing the interfacial impedance between the active material and the solid electrolyte, thereby improving the performance of the solid-state battery.

[0011] In any embodiment of this application, the ionic conductivity of the halide oxide solid electrolyte at 25°C is 0.45 mS / cm - 2 mS / cm. This is beneficial for improving the cycle performance of solid-state batteries using this halide oxide solid electrolyte.

[0012] In any embodiment of this application, the M element is Zr, and in the X-ray diffraction pattern of the halide oxide solid electrolyte, peaks are observed at positions 2θ = 32.30° ± 0.50° and 2θ = 33.70° ± 0.50°, respectively. The intensity of the peak at 2θ = 32.30° ± 0.50° is I. A The intensity of the peak appearing at the position 2θ = 33.70° ± 0.50° is I. B Satisfying: I A / I B >1. This helps to improve the amorphization degree of the halide oxide solid electrolyte, thereby reducing stress concentration at the interface between the halide oxide solid electrolyte and the positive electrode active material, resulting in higher interface stability between the halide oxide solid electrolyte and the positive electrode active material, which in turn helps to further improve the cycle stability of solid-state batteries.

[0013] In any embodiment of this application, the crystalline phase of the halide oxide solid electrolyte includes crystalline phase A and crystalline phase B, wherein the crystalline phase A is composed of halide oxide solid electrolyte and the crystalline phase B is composed of lithium oxide.

[0014] In any embodiment of this application, the Dv50 of the positive electrode active material is 2μm-6μm.

[0015] In any embodiment of this application, the solid-state battery is an all-solid-state battery.

[0016] A second aspect of this application provides a method for preparing a solid-state battery, the solid-state battery comprising a positive electrode layer, the positive electrode layer comprising a positive electrode active material layer, the positive electrode active material layer comprising a mixture of positive electrode active materials and a solid electrolyte, the solid electrolyte comprising a halide oxide solid electrolyte; the preparation method includes the step of preparing a halide oxide solid electrolyte, the preparation method of the halide oxide solid electrolyte comprising:

[0017] The halide oxide solid electrolyte is prepared by mixing a metal halide salt with an oxygen source; wherein the molar ratio of the metal halide salt to the oxygen source is ≥1 / 3, the metal halide salt contains an element M, the element M includes one or more of Zr, Fe, Al and Cr, and the molar ratio of halogen to oxygen in the halide oxide solid electrolyte is m / b, where m is the absolute value of the valence of the element M in the halide oxide solid electrolyte, and 0 < b ≤ 3.

[0018] In any embodiment of this application, the method for preparing the halide oxide solid electrolyte includes one or more of the following conditions:

[0019] (1) The molar ratio of the metal halide to the oxygen source is 1:(1-3);

[0020] (2) The halogen contained in the metal halide includes one or more of F, Cl and Br;

[0021] (3) The oxygen source includes one or more of lithium oxide and lithium hydroxide;

[0022] (4) The metal halide and the oxygen source are mixed by ball milling;

[0023] (5) The metal halide and the oxygen source are mixed by ball milling. The ball milling speed is 400rpm-700rpm, the time is 6h-12h, and the ball-to-material ratio is (20-60):1.

[0024] In any embodiment of this application, the molar ratio of the metal halide to the oxygen source is 1:(1-2).

[0025] In any embodiment of this application, the molar ratio of the metal halide to the oxygen source is 1:(1.25-2).

[0026] A third aspect of this application provides a positive electrode sheet, the positive electrode sheet comprising a positive electrode active material layer, the positive electrode active material layer comprising a mixture of positive electrode active materials and a solid electrolyte, the solid electrolyte comprising a halide oxide solid electrolyte, the halide oxide solid electrolyte containing an element M, the element M comprising one or more of Zr, Fe, Al and Cr, the molar ratio of halogen to oxygen in the halide oxide solid electrolyte being m / b, wherein m is the absolute value of the valence of the element M in the halide oxide solid electrolyte, 0 < b ≤ 3.

[0027] In any embodiment of this application, the positive electrode is the positive electrode layer in the solid-state battery of the first aspect of this application.

[0028] The fourth aspect of this application provides an electrical device, including at least one of the solid-state battery of the first aspect of this application and the solid-state battery prepared by the preparation method of the solid-state battery of the second aspect of this application.

[0029] Details of one or more embodiments or examples of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0030] To better describe and illustrate the implementation methods, embodiments, or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described implementation methods, embodiments, or examples, or the best mode of these applications as currently understood.

[0031] In the attached diagram:

[0032] Figure 1 shows the XRD patterns of the halide oxide solid electrolytes prepared in Examples 1-7.

[0033] Figure 2 shows the 0.1C first charge-discharge curve of the solid-state battery in Example 3.

[0034] Figure 3 is a schematic diagram of a solid-state battery cell according to an embodiment of this application.

[0035] Figure 4 is an exploded view of a solid-state battery cell according to an embodiment of this application, as shown in Figure 3.

[0036] Figure 5 is a schematic diagram of a battery device according to an embodiment of this application.

[0037] Figure 6 is a schematic diagram of a battery pack according to one embodiment of this application.

[0038] Figure 7 is an exploded view of the battery pack of one embodiment of this application shown in Figure 6.

[0039] Figure 8 is a schematic diagram of an electrical device using a solid-state battery as a power source according to an embodiment of this application.

[0040] Explanation of reference numerals in the attached drawings: 1, battery pack; 2, upper casing; 3, lower casing; 4, battery assembly; 5, solid-state battery cell; 51, casing; 52, solid-state battery cell; 53, cover plate; 6, electrical device. Detailed Implementation

[0041] The following describes in detail, with appropriate reference to the accompanying drawings, some embodiments of the solid-state battery and its fabrication method, positive electrode layer, and power application device of this application. However, some unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0042] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be included or excluded independently and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when describing a parameter as an integer ≥ 2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 for that parameter. For instance, when describing a parameter as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0043] In this application, unless otherwise specified, "about" means within a reasonable range above and below the stated number, and the range of fluctuation may vary depending on the type and value of the stated number. For example, a range of ±10%, ±5%, ±2%, ±1%, etc., may be allowed. For example, taking "about 20°C" and its approximation as ±1°C, approximate values ​​such as 19°C, 19.5°C, etc., within the approximation range indicated by "about 20°C" should also be included in the range indicated by "about 20°C".

[0044] In this application, the terms "multiple," "various," "multiple items," "several," etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more (greater than or equal to) two. It can be understood that when "any number of" items are involved, it refers to any suitable combination of multiple items, that is, a combination of "any number of" items in a manner that does not conflict and enables the implementation of this application.

[0045] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0046] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0047] Those skilled in the art will understand that the order in which the steps are written in the various implementations or embodiments does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps in this application may be performed sequentially or randomly, but are preferably performed sequentially. For example, method A includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, method A may also include step (c), indicating that step (c) can be added to method A in any order. For example, method A may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0048] In this application, unless otherwise specified, Q (e.g., q1) means that q1 is a non-limiting example of Q, and it can be understood that Q is not limited to q1.

[0049] In this application, unless otherwise stated, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items, wherein any and all combinations include any two of the related listed items, any more of the related listed items, or a combination of all the related listed items.

[0050] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0051] In this document, the term "suitable" in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the technical solution that enables the implementation of this application.

[0052] In this application, terms such as "further," "even more," "especially," "for example," "as," "example," and "exemplary" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0053] In this application, the terms "first aspect," "second aspect," "third aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0054] In this application, the exemplary descriptions such as "in some implementations (or embodiments)" and "in one implementation (or embodiment)" may cover, but are not limited to, the following meanings: these solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0055] Solid electrolyte materials are key to determining the performance of all-solid-state batteries. Traditional Li-MX halide electrolytes have low ionic conductivity, resulting in poor cycle performance of solid-state batteries using this type of solid electrolyte; furthermore, the presence of rare earth metals in their structure leads to high large-scale production costs. Conventional sulfide solid electrolytes readily react with water to produce toxic H2S gas, posing certain safety hazards to solid-state batteries formed from them.

[0056] To address the aforementioned issues, this application introduces a halide oxide solid electrolyte that does not contain rare or precious metals into the positive electrode active material layer. Simultaneously, it employs a strategy of mixing halogen and oxygen elements and adjusts the molar ratio of halogen and oxygen elements to improve the amorphization degree of the halide oxide solid electrolyte, thereby enhancing its ionic conductivity and significantly reducing its production cost.

[0057] Unless otherwise specified, the term "solid-state battery" in this application refers to a battery in which the electrolyte includes a solid electrolyte. Typically, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. During charging and discharging, active ions repeatedly insert and extract between the positive and negative electrode layers. The solid electrolyte layer acts as a conductor of ions between the positive and negative electrode layers and also isolates them, preventing short circuits. Therefore, a separator, as found in traditional lithium-ion batteries, is not required in solid-state batteries. Solid-state batteries use a non-flammable solid electrolyte instead of the organic electrolyte in traditional liquid lithium-ion batteries, significantly improving battery safety. In addition to enhanced safety, solid-state batteries are better suited for high-energy-density positive and negative electrode materials and reduce system weight, thus facilitating improvements in energy density.

[0058] In this application, unless otherwise specified, "solid electrolyte" refers to an electrolyte material or substance that exists in solid form during the storage and fabrication of solid-state batteries and their components, as well as during the operation of solid-state batteries. This includes, but is not limited to, solid electrolytes existing in solid form at room temperature.

[0059] In this application, unless otherwise specified, "electrode layer" includes electrode active material. The electrode layer can be a positive electrode layer or a negative electrode layer. "Electrode active material" in the electrode layer refers to a material capable of reversibly inserting and extracting active ions. Unless otherwise specified, "negative electrode active material" refers to a material used in the negative electrode layer capable of reversibly inserting and extracting active ions; "positive electrode active material" refers to a material used in the positive electrode layer capable of reversibly extracting and inserting active ions. During solid-state battery charging, active ions are extracted from the positive electrode, pass through the solid electrolyte layer, and insert into the negative electrode; while during solid-state battery discharging, active ions are extracted from the negative electrode and insert into the positive electrode. The active ions are not particularly limited or restrictive; they can be lithium ions, corresponding to a lithium-ion solid-state battery.

[0060] One or more embodiments of this application provide a solid-state battery, including a positive electrode layer, the positive electrode layer including a positive electrode active material layer, the positive electrode active material layer comprising a mixture of positive electrode active materials and a solid electrolyte, the solid electrolyte including a halide oxide solid electrolyte, the halide oxide solid electrolyte containing an element M, the element M including one or more of Zr, Fe, Al and Cr, the molar ratio of halogen and oxygen elements contained in the halide oxide solid electrolyte being m / b, where m is the absolute value of the valence of element M in the halide oxide solid electrolyte, 0 < b ≤ 3.

[0061] It should be noted that the halide oxide solid electrolyte contained in the positive electrode active material layer can enhance the ion conduction capacity of the positive electrode layer and reduce the interfacial impedance, thereby promoting the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity.

[0062] Understandably, introducing a halide oxide solid electrolyte into the positive electrode active material layer can significantly improve the ionic conductivity of the composite positive electrode, thereby enhancing the performance of solid-state batteries. Simultaneously, by controlling the molar ratio of halogens to oxygen in the halide oxide solid electrolyte, the amorphization degree of the halide oxide solid electrolyte can be effectively improved, thereby reducing stress concentration at the interface between the halide oxide solid electrolyte and the positive electrode active material. This results in higher interfacial stability between the halide oxide solid electrolyte and the positive electrode active material, further improving the cycle stability of solid-state batteries. Furthermore, halide oxide solid electrolytes do not contain rare or precious metals, significantly reducing their production costs.

[0063] As an example, the components contained in the positive electrode active material layer can be determined using inductively coupled plasma (ICP) testing. For instance, inductively coupled plasma optical emission spectrometers (ICP OES) can be used for measurement. The testing method can be as follows:

[0064] The positive electrode layer is obtained by disassembling a solid-state battery. Powder is scraped from the positive electrode layer, and 0.5g of powder is collected as a sample to be tested. The powder is digested, and then the types and contents of each element in the sample are tested to determine the components contained in the positive electrode active material layer.

[0065] In some optional implementations, 1 ≤ b ≤ 3; for example, it can be, but is not limited to, 1, 1.2, 1.25, 1.4, 1.5, 1.6, 1.75, 1.8, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, or any range between any two of the above values. Optionally, 1 ≤ b ≤ 2, and more specifically, 1.25 ≤ b ≤ 2.

[0066] In some implementations, 3 ≤ m ≤ 4, and m is a positive integer.

[0067] In some embodiments, the molar ratio m / b of halogens and oxygen in the halide oxide solid electrolyte is 3:(1-3) or 4:(1-3). Optionally, the molar ratio m / b of halogens and oxygen in the halide oxide solid electrolyte is 4:(1-3).

[0068] In some exemplary embodiments, the molar ratio m / b of halogens and oxygen in the halide oxide solid electrolyte is 3:(1-2) or 4:(1-2). Optionally, the molar ratio m / b of halogens and oxygen in the halide oxide solid electrolyte is 4:(1-2).

[0069] In some implementations, the M element is selected from one or more of Zr, Fe, Al, and Cr.

[0070] In some embodiments, the chemical formula of the halide oxide solid electrolyte is Li. a MX m O b Where X is one or more of F, Cl and Br, 0 < a ≤ 6, 0 < b ≤ 3, and m is the absolute value of the oxidation state of element M in the halide oxide solid electrolyte.

[0071] In some implementations, a = 2b.

[0072] As one possible implementation, the Dv50 of the halide oxide solid electrolyte is less than or equal to the Dv50 of the positive electrode active material. This, on the one hand, helps increase the contact sites between halide oxide solid electrolyte particles, forming better ion transport channels; on the other hand, it increases the contact area between the halide oxide solid electrolyte and the positive electrode active material, improving the cycle stability of the solid-state battery.

[0073] It should be noted that Dv50 mentioned in the context refers to the particle size corresponding to 50% of the volume distribution. As an example, Dv50 can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, in accordance with GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method.

[0074] As one possible implementation, the Dv50 of the halide oxide solid electrolyte is 0.5 μm-3.5 μm.

[0075] In some embodiments, the Dv50 of the halide oxide solid electrolyte is 1 μm-3 μm; for example, it can be, but is not limited to, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm, 3 μm, or any range between two of the above values. This results in more contact sites between the halide oxide solid electrolyte particles, forming better ion transport channels.

[0076] It should be noted that the Dv50 of halide oxide solid electrolytes mentioned in the context refers to the particle size corresponding to 50% of the volume distribution of the halide oxide solid electrolyte. As an example, Dv50 can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, according to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method. The test can be performed as follows: Weigh the halide oxide solid electrolyte sample to be tested, dissolve it in anhydrous ethanol, and then place it in the laser particle size analyzer for testing. The specific testing procedure can be as follows:

[0077] Weigh 0.1g-0.13g of the halide oxide solid electrolyte sample to be tested into a 50mL beaker, add 5g of anhydrous ethanol, place a stir bar of about 2.5mm in the beaker, and seal with plastic wrap. After sonicating the sample for 5 minutes, transfer it to a magnetic stirrer and stir at 500 rpm for at least 20 minutes. Two samples from each batch of product are taken and tested using a laser particle size analyzer.

[0078] As one possible implementation, the halide oxide solid electrolyte accounts for 3%-40% of the mass of the positive electrode active material layer.

[0079] In some embodiments, the mass percentage of the halide oxide solid electrolyte in the positive electrode active material layer is 5%-35%; for example, it can be, but is not limited to, 5%, 7%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 35%, or any range between two of the above mass percentages. When the mass percentage of the halide oxide solid electrolyte in the positive electrode active material layer is within the above range, a good electron / ion transport channel can be constructed in the positive electrode layer, reducing the interfacial impedance between the active material and the solid electrolyte, thereby improving the performance of the solid-state battery.

[0080] It should be noted that the mass percentage of the halide oxide solid electrolyte in the positive electrode active material layer mentioned in the context can be determined using inductively coupled plasma (ICP) testing. For example, it can be determined using inductively coupled plasma optical emission spectrometers (ICP OES). The testing method can be as follows:

[0081] The positive electrode layer is obtained by disassembling a solid-state battery. Powder is scraped from the positive electrode layer, and 0.5g of powder is collected as a sample to be tested. The powder is digested, and then the contents of Li, Ni, Mn and M elements in the sample are tested. The proportion of halide oxide solid electrolyte can be obtained based on the mass concentration of M element, and then the mass ratio of halide oxide solid electrolyte in the positive electrode active material layer is determined.

[0082] In some embodiments, the ionic conductivity of the halide oxide solid electrolyte at 25°C is 0.45 mS / cm to 2 mS / cm; for example, it can be, but is not limited to, 0.45 mS / cm, 0.5 mS / cm, 0.6 mS / cm, 0.7 mS / cm, 0.8 mS / cm, 0.9 mS / cm, 1 mS / cm, 1.1 mS / cm, 1.2 mS / cm, 1.3 mS / cm, 1.4 mS / cm, 1.5 mS / cm, 1.6 mS / cm, 1.7 mS / cm, 1.8 mS / cm, 1.9 mS / cm, 2 mS / cm, or any range between two of the above ionic conductivity values. This is beneficial for improving the cycle performance of solid-state batteries using this halide oxide solid electrolyte.

[0083] In some embodiments, element M is Zr, and in the X-ray diffraction pattern of the halide oxide solid electrolyte, peaks are observed at positions 2θ = 32.30° ± 0.50° and 2θ = 33.70° ± 0.50°, respectively. The intensity of the peak at 2θ = 32.30° ± 0.50° is I. A The intensity of the peak appearing at the position 2θ = 33.70° ± 0.50° is I. B Satisfying: I A / I B >1. This helps to improve the amorphization degree of the halide oxide solid electrolyte, thereby reducing stress concentration at the interface between the halide oxide solid electrolyte and the positive electrode active material, resulting in higher interface stability between the halide oxide solid electrolyte and the positive electrode active material, which in turn helps to further improve the cycle stability of solid-state batteries.

[0084] It should be noted that the "I" mentioned in the context... A / I BThe determination can be performed as follows: Add the halide oxide solid electrolyte powder into the groove of the X-ray diffractometer (XRD) sample stage, compact the powder, and attach PI tape to the powder surface to ensure no air exposure during the test. Adjust the appropriate diffraction angle range and scanning speed, and use CuKα radiation. Perform measurement I A and I B For example, the diffraction angle range can be from 10° to 70°, and the scanning speed can be 0.2° per second.

[0085] In some embodiments, the crystalline phases of the halide oxide solid electrolyte include crystalline phase A and crystalline phase B, wherein crystalline phase A is composed of halide oxide solid electrolyte and crystalline phase B is composed of lithium oxide.

[0086] It should be noted that the intensity of the peak appearing in crystalline phase A at the position of 2θ = 32.30° ± 0.50° is I. A The intensity of the peak appearing at position 2θ = 33.70° ± 0.50° in crystalline phase B is I. B .

[0087] As one possible implementation, the Dv50 of the positive electrode active material is 2μm-6μm. For example, it can be, but is not limited to, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, 6μm, or any range between two of the above particle sizes.

[0088] It should be noted that the Dv50 of the aforementioned positive electrode active material refers to the particle size corresponding to 50% of the volume distribution of the positive electrode active material. As an example, Dv50 can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, according to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method. The test can be performed as follows: Weigh the positive electrode active material sample to be tested, dissolve it in anhydrous ethanol, and then place it in the laser particle size analyzer for testing. The specific testing procedure can be as follows:

[0089] Weigh 0.1g-0.13g of the positive electrode active material sample to be tested into a 50mL beaker, add 5g of anhydrous ethanol, place a stir bar of about 2.5mm in the beaker, and seal with plastic wrap. After sonicating the sample for 5 minutes, transfer it to a magnetic stirrer and stir at 500 rpm for at least 20 minutes. Two samples from each batch of product are taken and tested using a laser particle size analyzer.

[0090] As one possible implementation method, the solid-state battery is an all-solid-state battery.

[0091] In this application, unless otherwise specified, "all-solid-state battery" refers to a solid-state battery in which all electrolytes are solid electrolytes. In this case, the positive electrode layer, negative electrode layer and electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery, so it can be called "all-solid-state battery".

[0092] A solid-state battery includes at least one solid-state battery cell. A solid-state battery may include one or more solid-state battery cells.

[0093] In this application, unless otherwise specified, "solid-state battery cell" refers to a basic unit capable of converting chemical energy into electrical energy, and all its components are solid-state. In some embodiments, a solid-state battery cell may be an all-solid-state battery cell.

[0094] In this application, unless otherwise specified, "all-solid-state battery cell" refers to a solid-state battery cell in which all electrolytes are solid electrolytes. In this case, the positive electrode layer, negative electrode layer and electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery cell, so it can be called "all-solid-state battery cell".

[0095] In some implementations, a solid-state battery cell includes a solid-state battery cell.

[0096] In some implementations, the solid-state cell is an all-solid-state cell.

[0097] In some embodiments, a solid-state battery cell (which may be an all-solid-state battery cell) includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0098] The positive electrode layer can be prepared using either a dry or wet method. For example, it can be prepared by dry pressing. Alternatively, it can be prepared by wet coating and drying.

[0099] Unless otherwise stated, the positive electrode layer in this application includes at least a positive electrode active material layer.

[0100] In some embodiments, the positive electrode active material may be a known positive electrode active material for batteries. As a non-limiting example, the positive electrode active material may include one or more of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds. Non-limiting examples of lithium-containing phosphates with an olivine structure include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium manganese iron phosphate and carbon composites. 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 known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 Examples of lithium nickel cobalt aluminum oxides include LiNi, etc. 0.80 Co 0.15 Al 0.05 O2. Examples of lithium iron phosphate include LiFePO4 (also known as LFP). Examples of lithium manganese phosphate include LiMnPO4.

[0101] Understandably, lithium (Li) is intercalated and deintercalated during the charging and discharging process of a battery, and the Li content in the positive electrode varies depending on the state of discharge. In the exemplary description of the positive electrode active material in this application, unless otherwise specified, the Li content can be the initial state of the material or a non-initial state after charge-discharge cycles. When the positive electrode active material is applied to the positive electrode in a battery system, the Li content in the positive electrode active material at the positive electrode will usually change after charge-discharge cycles. The Li content can be measured in atomic molar content, but is not limited to this. Regarding "Li content is the initial state of the material," the initial state of the material refers to the state before it is formed into the positive electrode active material layer. It is understood that new materials or substances obtained by appropriate modification based on the listed positive electrode active materials are also within the scope of positive electrode active materials. The aforementioned appropriate modification refers to an acceptable modification method for the positive electrode active material, and non-limiting examples include coating modification.

[0102] In the exemplary description of the positive electrode active material in this application, the oxygen (O) content is only a theoretical value. Lattice oxygen release will cause changes in the atomic molar content of oxygen, and the actual O content will fluctuate. The O content can be measured in atomic molar content, but is not limited to this.

[0103] Without limitation, the weight percentage of positive electrode active particles or positive electrode active materials in the positive electrode active material layer can be ≥70wt%, further ≥80wt%, even further ≥90wt%, and can also be 70wt% to 99wt%, optionally 80wt% to 95wt%.

[0104] 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, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs), and graphene. Non-limitingly, the weight percentage of the positive electrode conductive agent in the positive electrode active material layer may be 0–10 wt%, more further 0–8 wt%, even further 0–5 wt%, and even further 0.1 wt%–3 wt%. When the positive electrode material is prepared into a positive electrode active material layer using a dry method, the positive electrode conductive agent can be incorporated into the positive electrode material, which can improve the conductivity of the positive electrode active material layer.

[0105] In some embodiments, the positive electrode layer can be prepared by: dry mixing the components used to prepare the positive electrode layer, such as positive electrode active material particles, halide oxide solid electrolyte, positive electrode conductive agent, and any other components; then heating and pressurizing the mixed material to form a clump; and applying this clump to one side of the solid electrolyte layer for hot rolling to form the positive electrode layer. Non-limitingly, a dual planetary mixer can be used for dry mixing. Non-limitingly, a kneading mixer can be used for heated and pressurized kneading. Non-limitingly, the temperature for hot rolling can be 75°C to 85°C, and further, such as 78°C, 80°C, 82°C, etc.

[0106] The negative electrode layer can be prepared by dry or wet methods. For example, it can be formed by dry pressing. Alternatively, it can be formed by wet coating.

[0107] In this application, unless otherwise specified, the negative electrode layer includes at least a negative electrode active material layer.

[0108] Without limitation, the negative electrode active material layer may include a solid electrolyte. The solid electrolyte in the negative electrode active material layer may be referred to as "negative electrode electrolyte particles".

[0109] In this application, unless otherwise specified, "negative electrode electrolyte particles" refers to solid electrolytes that can be used in the negative electrode layer. Negative electrode electrolyte particles can enhance the ion conductivity of the negative electrode layer, reduce interfacial impedance, and promote the charge transfer efficiency and full release of the capacity of the negative electrode active material with the external environment.

[0110] In this application, unless otherwise specified, "negative electrode active particles" refers to particles containing negative electrode active substances that have the ability to reversibly insert and extract active ions.

[0111] In some embodiments, the negative electrode layer includes a negative electrode active material layer, which includes negative electrode active particles containing negative electrode active material.

[0112] Without limitation, the weight percentage of negative electrode active particles or negative electrode active materials in the negative electrode active material layer can be ≥80wt%, and more preferably ≥90wt%.

[0113] Non-limiting, the weight percentage of the negative electrode electrolyte particles in the negative electrode active material layer can be 0 to 30 wt%, preferably 0.1 wt% to 30 wt%, and further preferably 5 wt% to 20 wt%.

[0114] In some embodiments, the negative electrode active particles or negative electrode active material are lithium indium alloys (InLi alloys).

[0115] In some implementations, the negative electrode layer is an InLi alloy film.

[0116] In some embodiments, the negative electrode active material may also be a negative electrode active material known in the art for use in solid-state batteries. As a non-limiting example, the negative electrode active material may include one or more of the following materials: elemental silicon, elemental tin, silicon-carbon composites, silicon suboxide, graphite, and metallic lithium. However, this application is not limited to these materials or substances, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0117] In some embodiments, the negative electrode layer may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer comprising a negative electrode active material. As a non-limiting example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0118] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. In the negative electrode current collector, the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. In the negative electrode current collector, the composite current collector may be formed by forming a metal material on the polymer material substrate. Non-limiting examples of the metal material in the negative electrode current collector may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limiting examples of the polymer material substrate in the negative electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0119] In some embodiments, the negative electrode active material layer optionally includes a conductive agent (which may be referred to as a negative electrode conductive agent). Non-limitingly, the negative electrode conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. Non-limitingly, the weight percentage of the negative electrode conductive agent in the negative electrode active material layer may be 0–15 wt%, more preferably 0–10 wt%, and even more preferably 0–5 wt%.

[0120] In some embodiments, the negative electrode active material layer optionally includes a binder (denoted as negative electrode binder). As a non-limiting example, the negative electrode binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). Non-limitingly, the weight percentage of the negative electrode binder in the negative electrode active material layer may be 0–10 wt%, more further 0–5 wt%, even more further 1 wt%–5 wt%, and even more preferably 1 wt%–3 wt%.

[0121] In some embodiments, the negative electrode active material layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)). The weight percentage of the other additives in the negative electrode active material layer may be 0–15 wt%, more preferably 0–10 wt%, even more preferably 0–5 wt%, even more preferably 0–3 wt%, and even more preferably 0–2 wt%.

[0122] In some embodiments, the negative electrode layer can be prepared by dispersing the components used to prepare the negative electrode layer, such as negative electrode active particles, negative electrode electrolyte particles, negative electrode conductive agent, negative electrode binder, and any other components, in a solvent to form a negative electrode slurry. Further, the negative electrode slurry is coated onto at least one surface of the negative electrode current collector, and after drying, cold pressing, and other processes, the negative electrode layer is obtained. Cold pressing can be performed using a cold rolling mill. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 30wt% to 70wt%, optionally 40wt% to 60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000 mPa·s to 10000 mPa·s, optionally 3000 mPa·s to 10000 mPa·s. When coating the negative electrode slurry, the coating density per unit area (after deducting solvent) on a dry weight basis, based on the amount coated on one side of the negative electrode current collector, can be 1.5 mg / cm³. 2 ~22mg / cm 2 However, this is not the only possibility. The compaction density of the negative electrode sheet can be 1.0 g / cm³. 3 ~2.0g / cm 3 1.0g / cm can be selected. 3 ~1.8g / cm 3 .

[0123] A solid electrolyte layer can be introduced by forming electrode layers on both sides of the solid electrolyte membrane, or it can be introduced on the electrode layer.

[0124] The solid electrolyte layer acts as a conductor of ions between the positive and negative electrode layers, and can also isolate the positive and negative electrode layers to prevent short circuits between them.

[0125] It is understood that the solid electrolyte layer includes a solid electrolyte. The solid electrolyte in the solid electrolyte layer can be a solid electrolyte known in the art that can be used in solid-state batteries.

[0126] The types of solid electrolytes present in different film layers of a solid-state battery can be the same or different. For example, the solid electrolytes in the positive electrode layer and the solid electrolyte layer can be the same or different.

[0127] As a non-limiting example, in different film layers of a solid-state battery, the solid electrolyte may include one or more of the following: sulfide solid electrolyte, halide solid electrolyte, oxide solid electrolyte, polymer solid electrolyte, etc.

[0128] As another non-limiting example, in different film layers of a solid-state battery, the solid electrolyte can be, but is not limited to, one or more of oxide-based solid electrolytes, sulfide-based solid electrolytes, and halide-based solid electrolytes. In some embodiments, the solid electrolyte can independently include, but is not limited to, one or more of Argyrodite-type sulfide electrolytes and halide electrolytes. Non-limiting examples of oxide-based solid electrolytes may include LISICON-type oxide electrolytes (such as γ-Li3PO4), NASICON-type oxide electrolytes (such as Li... 1+x Al x Ge 2-x (PO4)3,Li 1+x Al x Ti 2-x (PO4)3, etc., 0≤x≤1), Garnet type (such as Li7La3Zr2O12, etc.), perovskite type oxide electrolytes (such as Li 3x La 2 / 3-x One or more of the following: TiO3, etc., 0≤x≤0.5, etc. Non-limiting examples of sulfide solid electrolytes may include Li... 10 GeP2S 12 Li₂S-P₂S₅, Argyrodite type (such as Li₆PS₅Cl, Li 5.5 PS 5.5 Cl 1.5 One or more of the following (etc.). Non-limiting examples of halide solid electrolytes may include one or more of the following: Li3InCl6, Li3YCl6, Li3ScCl6, Li3ErCl6, Li2ZrCl6, etc.

[0129] The solid electrolyte layer can be prepared using a dry method. In some embodiments, the solid electrolyte layer can be formed by pressing a solid electrolyte material into a solid electrolyte membrane. In other embodiments, the solid electrolyte layer is formed by pressing the constituent raw materials of the solid electrolyte layer onto an electrode layer. In still other embodiments, the solid electrolyte membrane can also be prepared using methods such as fibrosis combined with calendering.

[0130] In this application, the sheet-like solid electrolyte layer may also be referred to as a solid electrolyte membrane.

[0131] As a non-limiting example, the solid electrolyte layer can also be prepared by a wet process, wherein the electrolyte slurry used includes at least a solid electrolyte and an organic solvent, and typically also includes one or more of a binder and a dispersant.

[0132] In some embodiments, the thickness of the solid electrolyte layer can be 0.1 μm-1000 μm, and can be selected as 10 μm-100 μm, 100 μm-800 μm, 500 μm-800 μm, etc.

[0133] In some embodiments, the solid-state battery may include an outer packaging. This outer packaging can be used to encapsulate the aforementioned solid-state battery cell.

[0134] In some embodiments, the outer packaging of a solid-state battery can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of a solid-state battery can also be a soft pack, such as a pouch-type soft pack. The material of the soft pack can be plastic; further, non-limiting examples of plastics may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0135] This application does not impose any particular limitation on the shape of the solid-state battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 3 shows a square solid-state battery cell 5 as an example.

[0136] In some embodiments, referring to FIG4, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be placed over the opening to close the receiving cavity. A solid-state battery cell 52 is encapsulated within the receiving cavity. The number of solid-state battery cells 52 contained in the solid-state battery cell 5 may be one or more, which can be selected by those skilled in the art according to actual needs.

[0137] Solid-state batteries can be battery device 4 or battery pack 1.

[0138] The battery device includes at least one solid-state battery cell. The number of solid-state battery cells in the battery device can be one or more, and those skilled in the art can select an appropriate number according to the application and capacity of the battery device.

[0139] Figure 5 shows a battery device 4 as an example. Referring to Figure 5, in the battery device 4, multiple solid-state battery cells 5 can be arranged sequentially along the length of the battery device 4. Of course, they can also be arranged in any other arbitrary manner. Furthermore, the multiple solid-state battery cells 5 can be fixed in place by fasteners.

[0140] Optionally, the battery device 4 may also include a housing with a receiving space in which a plurality of solid-state battery cells 5 are housed.

[0141] In some embodiments, the battery devices described above can also be assembled into a battery pack, and the number of battery devices contained in the battery pack can be one or more. Those skilled in the art can select an appropriate number according to the application and capacity of the battery pack.

[0142] Figures 6 and 7 illustrate a battery pack 1 as an example. Referring to Figures 6 and 7, the battery pack 1 may include a battery compartment and multiple battery devices 4 disposed within the battery compartment. The battery compartment includes an upper compartment 2 and a lower compartment 3, the upper compartment 2 covering the lower compartment 3 to form a closed space for accommodating the battery devices 4. The multiple battery devices 4 can be arranged in any manner within the battery compartment.

[0143] One or more embodiments of this application provide a method for preparing a solid-state battery, which can be used to prepare the aforementioned solid-state battery. The method includes the step of preparing a halide oxide solid electrolyte, which comprises: mixing a metal halide salt with an oxygen source to prepare the halide oxide solid electrolyte; wherein the molar ratio of the metal halide salt to the oxygen source is ≥1 / 3, the metal halide salt contains an element M, which includes one or more of Zr, Fe, Al, and Cr, and the molar ratio of halogen to oxygen in the halide oxide solid electrolyte is m / b, where m is the absolute value of the valence of element M in the halide oxide solid electrolyte, and 0 < b ≤ 3.

[0144] In some embodiments, the molar ratio of the metal halide salt to the oxygen source is 1:(1-3); for example, it can be, but is not limited to, 1:1, 1:1.2, 1:1.25, 1:1.4, 1:1.5, 1:1.6, 1:1.75, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.5, 1:2.6, 1:2.8, 1:3, or any range between two of the above molar ratios. When the molar ratio of the metal halide salt to the oxygen source is within the above range, it is beneficial to adjust the molar ratio of halogen and oxygen elements in the prepared halide oxide solid electrolyte to be within a suitable range, thereby effectively improving the amorphization degree of the halide oxide solid electrolyte, reducing stress concentration at the interface between the halide oxide solid electrolyte and the positive electrode active material, improving the interface stability between the halide oxide solid electrolyte and the positive electrode active material, and enhancing the cycle stability of the solid-state battery.

[0145] In some alternative implementations, the molar ratio of the metal halide to the oxygen source is 1:(1-2).

[0146] In some exemplary embodiments, the molar ratio of the metal halide to the oxygen source is 1:(1.25-2).

[0147] As one possible implementation, the halogen contained in the metal halide includes one or more of F, Cl and Br.

[0148] As a non-limiting example, metal halide salts may include, but are not limited to, one or more of ZrCl4, ZrF4, ZrBr4, FeCl3, AlCl3, and CrCl3.

[0149] In some embodiments, the oxygen source includes one or more of lithium oxide and lithium hydroxide.

[0150] In some alternative embodiments, the oxygen source may also include lithium chloride; for example, the oxygen source may be a mixture of lithium oxide and lithium chloride, or a mixture of lithium hydroxide and lithium chloride.

[0151] As one possible implementation method, the metal halide and oxygen source are mixed by ball milling.

[0152] In some embodiments, the ball mill speed is 400 rpm to 700 rpm; for example, it can be, but is not limited to, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, or any range between two of the above speeds.

[0153] In some exemplary embodiments, the ball milling time is 6h-12h; for example, it can be, but is not limited to, 6h, 7h, 8h, 9h, 10h, 11h, 12h or any range between two of the above times.

[0154] In some alternative implementations, the ball-to-material ratio of the ball mill is (20-60):1; for example, it can be, but is not limited to, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1 or any range between two of the above ratios.

[0155] It should be noted that the ball mill speed, time, and ball-to-material ratio can be combined in any suitable way, and both can be selected from any ball mill speed, time, and ball-to-material ratio described in this article.

[0156] As a non-limiting example, the preparation method of a solid-state battery includes: Step S1, adding a metal halide salt and an oxygen source to a ball mill jar for ball milling and mixing to prepare a halide oxide solid electrolyte; wherein the metal halide salt contains an element M, which includes one or more of Zr, Fe, Al, and Cr. Step S2, pressing the solid electrolyte material into a solid electrolyte layer. Step S3, dry mixing positive electrode active material particles, halide oxide solid electrolyte, positive electrode conductive agent, and any other components, then heating and pressurizing the mixed material to form a clump, applying it to one side of the solid electrolyte layer for hot rolling to form a positive electrode layer; non-limitingly, a double planetary mixer can be used for dry mixing. Non-limitingly, a kneading machine can be used for heating and pressurizing. Non-limitingly, the temperature for hot rolling can be 75℃-85℃, further such as 78℃, 80℃, 82℃, etc. Step S4, applying a negative electrode layer to the opposite side of the solid electrolyte layer to prepare a solid-state battery.

[0157] As a non-limiting example, the solid electrolyte layer is prepared in step S2 by rolling. The rolling method can be cold rolling or hot rolling. A non-limiting example of a temperature for hot rolling is 180°C.

[0158] One or more embodiments of this application provide a positive electrode sheet, which includes a positive electrode active material layer. The positive electrode active material layer contains a mixture of positive electrode active materials and a solid electrolyte. The solid electrolyte includes a halide oxide solid electrolyte containing an element M. The element M includes one or more of Zr, Fe, Al, and Cr. The molar ratio of halogen to oxygen in the halide oxide solid electrolyte is m / b, where m is the absolute value of the valence of element M in the halide oxide solid electrolyte, and 0 < b ≤ 3.

[0159] In some optional implementations, 1 ≤ b ≤ 3; for example, it can be, but is not limited to, 1, 1.2, 1.25, 1.4, 1.5, 1.6, 1.75, 1.8, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, or any range between any two of the above values. Optionally, 1 ≤ b ≤ 2, and more specifically, 1.25 ≤ b ≤ 2.

[0160] In some implementations, 3 ≤ m ≤ 4, and m is a positive integer.

[0161] In some embodiments, the molar ratio m / b of halogens and oxygen in the halide oxide solid electrolyte is 3:(1-3) or 4:(1-3). Optionally, the molar ratio m / b of halogens and oxygen in the halide oxide solid electrolyte is 4:(1-3).

[0162] In some exemplary embodiments, the molar ratio m / b of halogens and oxygen in the halide oxide solid electrolyte is 3:(1-2) or 4:(1-2). Optionally, the molar ratio m / b of halogens and oxygen in the halide oxide solid electrolyte is 4:(1-2).

[0163] In some implementations, the M element is selected from one or more of Zr, Fe, Al, and Cr.

[0164] In some embodiments, the chemical formula of the halide oxide solid electrolyte is Li. a MX m O b Where X is one or more of F, Cl and Br, 0 < a ≤ 6, 0 < b ≤ 3, and m is the absolute value of the oxidation state of element M in the halide oxide solid electrolyte.

[0165] In some implementations, a = 2b.

[0166] As one possible implementation, the Dv50 of the halide oxide solid electrolyte is less than or equal to the Dv50 of the positive electrode active material. This, on the one hand, helps increase the contact sites between halide oxide solid electrolyte particles, forming better ion transport channels; on the other hand, it increases the contact area between the halide oxide solid electrolyte and the positive electrode active material, improving the cycle stability of the solid-state battery.

[0167] As one possible implementation, the Dv50 of the halide oxide solid electrolyte is 0.5 μm-3.5 μm.

[0168] In some embodiments, the Dv50 of the halide oxide solid electrolyte is 1 μm-3 μm. This results in more contact sites between the halide oxide solid electrolyte particles, forming better ion transport channels.

[0169] As one possible implementation, the halide oxide solid electrolyte accounts for 3%-40% of the mass of the positive electrode active material layer.

[0170] In some embodiments, the mass percentage of the halide oxide solid electrolyte in the positive electrode active material layer is 5%-35%. When the mass percentage of the halide oxide solid electrolyte in the positive electrode active material layer is within the above range, a good electron / ion transport channel can be constructed in the positive electrode layer, reducing the interfacial impedance between the active material and the solid electrolyte, thereby improving the performance of the solid-state battery.

[0171] In some embodiments, the ionic conductivity of the halide oxide solid electrolyte at 25°C is 0.45 mS / cm to 2 mS / cm. This is beneficial for improving the cycle performance of solid-state batteries using this halide oxide solid electrolyte.

[0172] In some embodiments, element M is Zr, and in the X-ray diffraction pattern of the halide oxide solid electrolyte, peaks are observed at positions 2θ = 32.30° ± 0.50° and 2θ = 33.70° ± 0.50°, respectively. The intensity of the peak at 2θ = 32.30° ± 0.50° is I. A The intensity of the peak appearing at the position 2θ = 33.70° ± 0.50° is I. B Satisfying: I A / I B >1. This helps to improve the amorphization degree of the halide oxide solid electrolyte, thereby reducing stress concentration at the interface between the halide oxide solid electrolyte and the positive electrode active material, resulting in higher interface stability between the halide oxide solid electrolyte and the positive electrode active material, which in turn helps to further improve the cycle stability of solid-state batteries.

[0173] In some embodiments, the crystalline phases of the halide oxide solid electrolyte include crystalline phase A and crystalline phase B, wherein crystalline phase A is composed of halide oxide solid electrolyte and crystalline phase B is composed of lithium oxide.

[0174] As one possible implementation, the Dv50 of the positive electrode active material is 2μm-6μm.

[0175] One or more embodiments of this application provide an electrical device comprising at least one of the solid-state battery described above and a solid-state battery prepared by the method described above.

[0176] In some embodiments, the electrical device includes at least one of the solid-state batteries of any of the embodiments provided in this application.

[0177] In a non-limiting sense, solid-state batteries can be used as a power source for electrical devices or as an energy storage unit for electrical devices. Electrical devices can include, but are not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Mobile devices can be, for example, mobile phones, laptops, etc.; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric motorcycles, power tools, etc., but are not limited to these. This electrical device can also be applied to military equipment, aerospace, and other fields, and can also be applied to energy storage power systems such as hydroelectric, thermal, wind, and solar power plants.

[0178] As an electrical device, solid-state batteries can be selected based on its usage requirements.

[0179] Figure 8 shows an example of an electrical device 6. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device for solid-state batteries, a battery device or battery pack can be used.

[0180] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a thin and light design and can use solid-state batteries as their power source.

[0181] The following describes some embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where the technology or conditions are not specified in the embodiments, they are performed according to the description above, or according to the technology or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially, or can be synthesized from commercially available products using conventional methods.

[0182] I. Solid-state battery fabrication

[0183] Example 1

[0184] Step S1: Li₂O and ZrCl₄ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halooxide solid electrolyte Li₂ZrCl₄O. The ball-to-material ratio is 40:1, the milling speed is 650 rpm, and the milling time is 10 h. The Dv₅₀ of the halooxide solid electrolyte Li₂ZrCl₄O is 2 μm.

[0185] Step S2: Take the positive electrode active material particles LiNi according to a mass ratio of 68:30:2 0.8 Mn 0.1 Co 0.1O2, a halide oxide solid electrolyte Li2ZrCl4O, and conductive carbon black were added to a mortar and ground for 20 minutes to obtain a composite cathode material. The Dv50 of the cathode active material particles was 3 μm.

[0186] Step S3: Press 100 mg of sulfide electrolyte Li6PS5Cl into a sheet at 25 °C under a pressure of 1.5 T to obtain a solid electrolyte layer.

[0187] Step S4: Spread 20mg of composite positive electrode material on one side surface of the solid electrolyte layer, and hold it at 3t pressure at 25°C for 4 minutes to form a positive electrode layer;

[0188] Step S5: Add an indium sheet and a composite copper-lithium sheet with a diameter of 10 mm to the other side of the solid electrolyte layer, and assemble them under pressure in a mold to obtain a solid-state battery.

[0189] Example 2

[0190] The preparation methods for Example 2 and Example 1 are similar, except that in step S1 of Example 2, Li₂O and ZrCl₄ are mixed at a molar ratio of 1.25:1, while all other steps remain the same. The specific preparation method for Example 2 is as follows:

[0191] Step S1: Mix Li₂O and ZrCl₄ at a molar ratio of 1.25:1 until homogeneous, add the mixture to a sealed ball mill jar containing zirconium oxide, and ball mill to mix, thereby obtaining the halide oxide solid electrolyte Li. 2.5 ZrCl4O 1.25 The ball-to-material ratio was 40:1, the rotation speed was 650 rpm, and the ball milling time was 10 hours. The halide oxide solid electrolyte Li... 2.5 ZrCl4O 1.25 The Dv50 is 2μm.

[0192] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0193] Example 3

[0194] The preparation methods of Example 3 and Example 1 are similar, except that in step S1 of Example 3, Li2O and ZrCl4 are mixed at a molar ratio of 1.5:1, while all other steps are the same. The specific preparation method of Example 3 is as follows:

[0195] Step S1: Mix Li2O and ZrCl4 at a molar ratio of 1.5:1 until homogeneous, add the mixture to a sealed ball mill jar containing zirconium oxide, and ball mill to mix, thereby obtaining the halide oxide solid electrolyte Li3ZrCl4O. 1.5 The ball-to-material ratio was 40:1, the rotation speed was 650 rpm, and the ball milling time was 10 hours. The halide oxide solid electrolyte was Li3ZrCl4O.1.5 The Dv50 is 2μm.

[0196] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0197] Example 4

[0198] The preparation methods for Example 4 and Example 1 are similar, except that in step S1 of Example 4, Li₂O and ZrCl₄ are mixed at a molar ratio of 1.75:1, while all other steps remain the same. The specific preparation method for Example 4 is as follows:

[0199] Step S1: Mix Li₂O and ZrCl₄ at a molar ratio of 1.75:1 until homogeneous, add the mixture to a sealed ball mill jar containing zirconium oxide, and ball mill to mix, thereby obtaining the halide oxide solid electrolyte Li. 3.5 ZrCl4O 1.75 The ball-to-material ratio was 40:1, the rotation speed was 650 rpm, and the ball milling time was 10 hours. The halide oxide solid electrolyte Li... 3.5 ZrCl4O 1.75 The Dv50 is 2μm.

[0200] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0201] Example 5

[0202] The preparation methods of Example 5 and Example 1 are similar, except that in step S1 of Example 5, Li2O and ZrCl4 are mixed in a molar ratio of 2:1, while all other steps are the same. The specific preparation method of Example 5 is as follows:

[0203] Step S1: Li₂O and ZrCl₄ are mixed evenly at a molar ratio of 2:1, added to a sealed ball mill jar containing zirconium oxide, and ball-milled to obtain the halooxide solid electrolyte Li₄ZrCl₄O₂. The ball-to-material ratio is 40:1, the milling speed is 650 rpm, and the milling time is 10 h. The Dv₅₀ of the halooxide solid electrolyte Li₄ZrCl₄O₂ is 2 μm.

[0204] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0205] Example 6

[0206] The preparation methods of Example 6 and Example 1 are similar, except that in step S1 of Example 6, Li2O and ZrF4 are mixed in a molar ratio of 1:1, while all other steps are the same. The specific preparation method of Example 6 is as follows:

[0207] Step S1: Li₂O and ZrF₄ are mixed uniformly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halooxide solid electrolyte Li₂ZrF₄O. The ball-to-material ratio is 40:1, the milling speed is 650 rpm, and the milling time is 10 h. The Dv₅₀ of the halooxide solid electrolyte Li₂ZrF₄O is 2 μm.

[0208] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0209] Example 7

[0210] The preparation methods of Example 7 and Example 1 are similar, except that in step S1 of Example 7, Li2O and ZrBr4 are mixed in a molar ratio of 1:1, while all other steps are the same. The specific preparation method of Example 7 is as follows:

[0211] Step S1: Li2O and ZrF4 are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halooxide solid electrolyte Li2ZrBr4O; wherein the ball-to-material ratio is 40:1, the rotation speed is 650 rpm, and the ball milling time is 10 h. The Dv50 of the halooxide solid electrolyte Li2ZrBr4O is 2 μm.

[0212] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0213] Example 8

[0214] The preparation methods of Example 8 and Example 1 are similar, except that in step S1 of Example 8, Li₂O and FeCl₃ are mixed in a molar ratio of 1:1, while all other steps are the same. The specific preparation method of Example 8 is as follows:

[0215] Step S1: Li₂O and FeCl₃ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball-milled to obtain the halide oxide solid electrolyte Li₂FeCl₃O; wherein the ball-to-material ratio is 40:1, the rotation speed is 650 rpm, and the ball milling time is 10 h. The Dv₅₀ of the halide oxide solid electrolyte Li₂FeCl₃O is 2 μm.

[0216] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0217] Example 9

[0218] The preparation methods of Example 9 and Example 1 are similar, except that in step S1 of Example 9, Li₂O and AlCl₃ are mixed in a molar ratio of 1:1, while all other steps are the same. The specific preparation method of Example 9 is as follows:

[0219] Step S1: Li₂O and AlCl₃ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halide oxide solid electrolyte Li₂AlCl₃O; wherein the ball-to-material ratio is 40:1, the rotation speed is 650 rpm, and the ball milling time is 10 h. The Dv₅₀ of the halide oxide solid electrolyte Li₂AlCl₃O is 2 μm.

[0220] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0221] Example 10

[0222] The preparation methods of Example 10 and Example 1 are similar, except that in step S1 of Example 10, Li₂O and CrCl₃ are mixed in a molar ratio of 1:1, while all other steps are the same. The specific preparation method of Example 10 is as follows:

[0223] Step S1: Li₂O and CrCl₃ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halide oxide solid electrolyte Li₂CrCl₃O; wherein the ball-to-material ratio is 40:1, the rotation speed is 650 rpm, and the ball milling time is 10 h. The Dv₅₀ of the halide oxide solid electrolyte Li₂CrCl₃O is 2 μm.

[0224] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0225] Example 11

[0226] The preparation methods of Example 11 and Example 1 are similar, except that in step S1 of Example 11, Li2O and ZrCl4 are mixed in a molar ratio of 3:1, while all other steps are the same. The specific preparation method of Example 11 is as follows:

[0227] Step S1: Li₂O and ZrCl₄ are mixed evenly at a molar ratio of 3:1, added to a sealed ball mill jar containing zirconium oxide, and ball-milled to obtain the halooxide solid electrolyte Li₆ZrCl₄O₃; wherein the ball-to-material ratio is 40:1, the rotation speed is 650 rpm, and the ball milling time is 10 h. The Dv₅₀ of the halooxide solid electrolyte Li₆ZrCl₄O₃ is 2 μm.

[0228] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0229] Example 12

[0230] The preparation methods of Example 12 and Example 1 are similar, except that the grinding conditions in step S1 of Example 12 are different; all other conditions are the same. The specific preparation method of Example 12 is as follows:

[0231] Step S1: Li₂O and ZrCl₄ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halooxide solid electrolyte Li₂ZrCl₄O. The ball-to-material ratio is 40:1, the milling speed is 700 rpm, and the milling time is 12 h. The Dv₅₀ of the halooxide solid electrolyte Li₂ZrCl₄O is 1 μm.

[0232] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0233] Example 13

[0234] The preparation methods of Example 13 and Example 1 are similar, except that the grinding conditions in step S1 of Example 13 are different; all other conditions are the same. The specific preparation method of Example 13 is as follows:

[0235] Step S1: Li₂O and ZrCl₄ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball-milled to obtain the halooxide solid electrolyte Li₂ZrCl₄O. The ball-to-material ratio is 40:1, the milling speed is 650 rpm, and the milling time is 8 hours. The Dv₅₀ of the halooxide solid electrolyte Li₂ZrCl₄O is 3 μm.

[0236] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0237] Example 14

[0238] The preparation methods of Example 14 and Example 1 are similar, except that the grinding conditions in step S1 of Example 14 are different, and the Dv50 of the positive electrode active material particles in step S2 is 4 μm. All other conditions are the same. The specific preparation method of Example 14 is as follows:

[0239] Step S1: Li₂O and ZrCl₄ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halooxide solid electrolyte Li₂ZrCl₄O. The ball-to-material ratio is 40:1, the milling speed is 650 rpm, and the milling time is 4 hours. The Dv₅₀ of the halooxide solid electrolyte Li₂ZrCl₄O is 3.5 μm.

[0240] Step S2: Take the positive electrode active material particles LiNi according to a mass ratio of 68:30:2 0.8 Mn 0.1 Co 0.1O2, a halide oxide solid electrolyte Li2ZrCl4O, and conductive carbon black were added to a mortar and ground for 20 minutes to obtain a composite cathode material. The Dv50 of the cathode active material particles was 4 μm.

[0241] Steps S3-S5 are the same as steps S3-S5 in Example 1.

[0242] Example 15

[0243] The preparation methods of Example 15 and Example 1 are similar, except that the grinding conditions in step S1 of Example 15 are different; all other conditions are the same. The specific preparation method of Example 15 is as follows:

[0244] Step S1: Li₂O and ZrCl₄ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halooxide solid electrolyte Li₂ZrCl₄O. The ball-to-material ratio is 40:1, the milling speed is 800 rpm, and the milling time is 13 h. The Dv₅₀ of the halooxide solid electrolyte Li₂ZrCl₄O is 0.5 μm.

[0245] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0246] Example 16

[0247] The preparation methods of Example 16 and Example 1 are similar, except that the grinding conditions in step S1 of Example 16 are different; all other conditions are the same. The specific preparation method of Example 16 is as follows:

[0248] Step S1: Li₂O and ZrCl₄ are mixed evenly at a molar ratio of 1:1, added to a sealed ball mill jar containing zirconium oxide, and ball-milled to obtain the halooxide solid electrolyte Li₂ZrCl₄O. The ball-to-material ratio is 40:1, the milling speed is 650 rpm, and the milling time is 8 hours. The Dv₅₀ of the halooxide solid electrolyte Li₂ZrCl₄O is 3 μm.

[0249] Step S2: Take the positive electrode active material particles LiNi according to a mass ratio of 68:30:2 0.8 Mn 0.1 Co 0.1 O2, a halide oxide solid electrolyte Li2ZrCl4O, and conductive carbon black were added to a mortar and ground for 20 minutes to obtain a composite cathode material. The Dv50 of the cathode active material particles was 2.5 μm.

[0250] Steps S3-S5 are the same as steps S3-S5 in Example 1.

[0251] Example 17

[0252] The preparation methods of Example 17 and Example 1 are similar, except that the amount of the halide oxide solid electrolyte Li2ZrCl4O used in step S2 of Example 17 is different; all other aspects are the same. The specific preparation method of Example 17 is as follows:

[0253] Step S1 is the same as step S1 in Example 1.

[0254] Step S2: Take the positive electrode active material particles LiNi according to a mass ratio of 63:35:2. 0.8 Mn 0.1 Co 0.1 O2, a halide oxide solid electrolyte Li2ZrCl4O, and conductive carbon black were added to a mortar and ground for 20 minutes to obtain a composite cathode material. The Dv50 of the cathode active material particles was 3 μm.

[0255] Steps S3-S5 are the same as steps S3-S5 in Example 1.

[0256] Example 18

[0257] The preparation methods of Example 18 and Example 1 are similar, except that the amount of the halide oxide solid electrolyte Li2ZrCl4O used in step S2 of Example 18 is different; all other aspects are the same. The specific preparation method of Example 18 is as follows:

[0258] Step S1 is the same as step S1 in Example 1.

[0259] Step S2: Take the positive electrode active material particles LiNi according to a mass ratio of 93:5:2. 0.8 Mn 0.1 Co 0.1 O2, a halide oxide solid electrolyte Li2ZrCl4O, and conductive carbon black were added to a mortar and ground for 20 minutes to obtain a composite cathode material. The Dv50 of the cathode active material particles was 3 μm.

[0260] Steps S3-S5 are the same as steps S3-S5 in Example 1.

[0261] Example 19

[0262] The preparation methods of Example 19 and Example 1 are similar, except that the amount of the halide oxide solid electrolyte Li2ZrCl4O used in step S2 of Example 19 is different; all other aspects are the same. The specific preparation method of Example 19 is as follows:

[0263] Step S1 is the same as step S1 in Example 1.

[0264] Step S2: Take the positive electrode active material particles LiNi according to a mass ratio of 58:40:2 0.8 Mn 0.1 Co0.1 O2, a halide oxide solid electrolyte Li2ZrCl4O, and conductive carbon black were added to a mortar and ground for 20 minutes to obtain a composite cathode material. The Dv50 of the cathode active material particles was 3 μm.

[0265] Steps S3-S5 are the same as steps S3-S5 in Example 1.

[0266] Example 20

[0267] The preparation methods for Example 20 and Example 1 are similar, except that the amount of the halide oxide solid electrolyte Li2ZrCl4O used in step S2 of Example 20 is different; all other aspects are the same. The specific preparation method for Example 20 is as follows:

[0268] Step S1 is the same as step S1 in Example 1.

[0269] Step S2: Take the positive electrode active material particles LiNi according to a mass ratio of 95:3:2. 0.8 Mn 0.1 Co 0.1 O2, a halide oxide solid electrolyte Li2ZrCl4O, and conductive carbon black were added to a mortar and ground for 20 minutes to obtain a composite cathode material. The Dv50 of the cathode active material particles was 3 μm.

[0270] Steps S3-S5 are the same as steps S3-S5 in Example 1.

[0271] Comparative Example 1

[0272] The preparation methods for Comparative Example 1 and Example 1 are similar, except that in step S1 of Comparative Example 1, LiCl and ZrCl4 are mixed in a molar ratio of 2:1, while all other steps are the same. The preparation method for Example 2 is as follows:

[0273] Step S1: LiCl and ZrCl4 are mixed evenly at a molar ratio of 2:1, added to a sealed ball mill jar containing zirconium oxide, and ball milled to obtain the halooxide solid electrolyte Li2ZrCl6; wherein the ball-to-material ratio is 40:1, the rotation speed is 650 rpm, and the ball milling time is 10 h. The Dv50 of the halooxide solid electrolyte Li2ZrCl6 is 2 μm.

[0274] Steps S2-S5 are the same as steps S2-S5 in Example 1.

[0275] Comparative Example 2

[0276] The preparation methods for Comparative Example 2 and Example 1 are similar, except that in step S1 of Comparative Example 2, Li₂O and ZrCl₄ are mixed at a molar ratio of 3.5:1, while all other steps remain the same. The specific preparation method for Comparative Example 2 is as follows:

[0277] Step S1: Mix Li₂O and ZrCl₄ at a molar ratio of 3.5:1 until homogeneous, add the mixture to a sealed ball mill jar containing zirconium oxide, and ball mill to mix, thus obtaining the halide oxide solid electrolyte Li₇ZrCl₄O. 3.5 The ball-to-material ratio was 40:1, the rotation speed was 650 rpm, and the ball milling time was 10 hours. The halide oxide solid electrolyte was Li7ZrCl4O. 3.5 The Dv50 is 2μm.

[0278] Steps S2-S5 are the same as steps S2-S5 in Example 1. The solid-state batteries prepared in each of the above examples and comparative examples were subjected to measurements of the following parameters: Dv501 of the halide oxide solid electrolyte, Dv502 of the positive electrode active material, and the percentage w of the mass of the halide oxide solid electrolyte to the total mass of the halide oxide solid electrolyte and the positive electrode active material, etc. The results are shown in Table 1.

[0279] Table 1

[0280] In Table 1, Dv501 refers to the Dv50 of the halide oxide solid electrolyte in the positive electrode layer of the solid-state battery, and Dv502 refers to the Dv50 of the positive electrode active material in the positive electrode layer of the solid-state battery. W refers to the mass percentage of the halide oxide solid electrolyte in the positive electrode layer of the solid-state battery. The molar ratio refers to the molar ratio of oxygen source to metal halide salt used in the preparation of halide oxide solid electrolyte.

[0281] The mass percentage w of the halide oxide solid electrolyte in the positive electrode layer mentioned above was determined by the following method: the positive electrode layer was obtained by disassembling the solid-state battery, powder was scraped from the positive electrode layer, 0.5g of powder was collected as the sample to be tested, digested, and then the contents of Li, Ni, Mn and M elements in the sample to be tested were tested. Based on the mass concentration of M element, the proportion of halide oxide solid electrolyte can be obtained, and thus the mass percentage of halide oxide solid electrolyte in the positive electrode layer can be determined.

[0282] II. Performance Testing

[0283] 1. The halide oxide solid electrolytes prepared in Examples 1-7 and Comparative Example 1 were determined by X-ray diffraction. The specific determination method was as follows: CuKα radiation was applied to a Bruker AXS D8 Advance. The XRD patterns of the halide oxide solid electrolytes from Examples 1-7 are shown in Figure 1. As can be seen from Figure 1, the halide oxide solid electrolytes were successfully synthesized, and the peak at 2θ = 32.30° ± 0.50° was confirmed as the peak of crystalline phase A, and the peak at 2θ = 33.70° ± 0.50° was confirmed as the peak of crystalline phase B.

[0284] Peak intensities I of crystalline phase A in the solid electrolytes of Examples 1-7 and Comparative Example 1 A Peak intensity I of crystalline phase B B The ratios are shown in Table 2.

[0285] Table 2

[0286] As shown in Figure 1 and Table 2, by adjusting the ratio of metal halide salt to Li2O, the molar ratio of halogen to oxygen in the halide oxide solid electrolyte can be controlled, thereby improving the amorphization degree of the halide oxide solid electrolyte and thus enhancing the interfacial stability between the halide oxide solid electrolyte and the positive electrode active material.

[0287] 2. The ionic conductivity of the solid electrolytes in Examples 1-19 and Comparative Example 1 was tested. The test method was as follows: the ionic conductivity of the solid electrolyte was obtained by measuring the AC impedance spectrum. The test frequency range was 1MHz-1Hz, and the test temperature was 25℃. The specific test steps were as follows: 120mg of electrolyte powder was weighed in a glove box, poured into a measuring mold, and a pressure of 3t was applied to obtain an electrolyte sheet. Its thickness was measured and recorded as L, and its diameter was measured as d. The AC impedance of the battery under open circuit conditions was tested, and the obtained impedance value was recorded as R. The ionic conductivity was obtained using the formula σ=4L / πd2R.

[0288] The test results are shown in Table 3.

[0289] 3. Initial Discharge Capacity and Initial Coulombic Efficiency Tests: The assembled all-solid-state battery cells were charged to 3.68V (4.3V relative to lithium potential) at a current density of 0.1C, allowed to stand for 10 minutes, and then discharged to 1.98V (2.6V relative to lithium potential) at a current density of 0.1C to obtain the initial discharge specific capacity of the solid-state battery cells. The batteries were tested at 25°C, where 1C = 200mA / g. The initial coulombic efficiency of the solid-state battery cells was obtained by dividing the initial discharge specific capacity obtained at 0.1C by the initial charge capacity. The test results are shown in Table 3. The 0.1C initial charge-discharge curve of the solid-state battery in Example 3 is shown in Figure 2.

[0290] 4. Cyclic performance test

[0291] The cycle performance test method is as follows: The assembled all-solid-state battery cell is charged to 3.68V (4.3V relative to lithium potential) at a current density of 0.1C, allowed to stand for 10 minutes, and then discharged to 1.98V (2.6V relative to lithium potential) at a current density of 0.1C, completing one charge-discharge cycle; after 100 cycles at a 0.1C rate, the capacity retention rate is calculated. Capacity retention rate after 100 cycles = Discharge capacity after 100 cycles at 0.1C / Discharge capacity in the first cycle at 0.1C.

[0292] Table 3

[0293] As can be seen from the comparison of the results of Examples 1-20 and Comparative Examples 1-2 in Table 1, Examples 1-20 have higher ionic conductivity and better capacity and cycle performance compared with Comparative Examples 1-2. This shows that by introducing halide oxide solid electrolyte into the positive electrode layer of the solid-state battery and controlling the molar ratio of halogen and oxygen elements in the halide oxide solid electrolyte within a suitable range, this application can effectively improve the ionic conductivity of halide oxide solid electrolyte and enhance the cycle performance and capacity of solid-state battery.

[0294] A comparison of the results from Examples 1, 12-13, and 14-15 shows that by adjusting the Dv50 of the halide oxide solid electrolyte within the range of 1 μm-3 μm, it is beneficial to further improve the ionic conductivity of the halide oxide solid electrolyte, as well as enhance the cycle performance and capacity of the solid-state battery.

[0295] A comparison of the results from Examples 1, 12-13 and 16 shows that by adjusting the Dv50 of the halide oxide solid electrolyte to be less than or equal to the Dv50 of the positive electrode active material, it is also beneficial to further improve the ionic conductivity of the halide oxide solid electrolyte, as well as improve the cycle performance and capacity of the solid-state battery.

[0296] A comparison of the results from Examples 1, 17-18, and 19-20 shows that by further controlling the percentage of the mass of the halide oxide solid electrolyte in the total mass of the halide oxide solid electrolyte and the positive electrode active material to be within the range of 5%-35%, it is beneficial to further improve the ionic conductivity of the halide oxide solid electrolyte and enhance the cycle performance and capacity of the solid-state battery.

[0297] The descriptions of the various implementation methods and embodiments above tend to emphasize the differences between them. Similarities or resemblances can be referenced interchangeably, and for the sake of brevity, they will not be repeated here. The technical features of the implementation methods and embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combinations of these technical features do not contradict each other, they should be considered within the scope of this specification.

[0298] It should be noted that this application is not limited to the above-described embodiments and examples. The above-described embodiments and examples are merely examples, and any embodiments and examples that have the same structure and achieve the same effect as the technical concept within the scope of this application are included in the technical scope of this application. The embodiments and examples described above only illustrate several embodiments and examples of this application, and although the descriptions are relatively detailed, they should not be construed as limiting the scope of the patent. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments or examples, and other ways of constructing embodiments or examples by combining some of the constituent elements of the embodiments or examples, are also included in the scope of this application without departing from the spirit of this application.

Claims

A solid-state battery includes a positive electrode layer, the positive electrode layer comprising a positive electrode active material layer, the positive electrode active material layer comprising a mixture of positive electrode active materials and a solid electrolyte, the solid electrolyte comprising a halide oxide solid electrolyte containing an element M, the element M comprising one or more of Zr, Fe, Al and Cr, wherein the molar ratio of halogen to oxygen in the halide oxide solid electrolyte is m / b, wherein... m is the absolute value of the valence of element M in the halide oxide solid electrolyte, 0 < b ≤ 3. The solid-state battery as described in claim 1, wherein, The chemical formula of the halide oxide solid electrolyte is LiaMXmOb, wherein the element X includes one or more of F, Cl and Br, 0 < a ≤ 6, 0 < b ≤ 3, and m is the absolute value of the oxidation state of the element M in the halide oxide solid electrolyte. The solid-state battery according to any one of claims 1 to 2, wherein, The Dv50 of the halide oxide solid electrolyte is less than or equal to the Dv50 of the positive electrode active material. The solid-state battery according to any one of claims 1 to 3, wherein, The Dv50 of the halide oxide solid electrolyte is 1μm-3μm. The solid-state battery according to any one of claims 1 to 4, wherein, The halide oxide solid electrolyte accounts for 5%-35% of the mass of the positive electrode active material layer. The solid-state battery according to any one of claims 1 to 5, wherein, The ionic conductivity of the halide oxide solid electrolyte at 25°C is 0.45 mS / cm - 2 mS / cm. The solid-state battery according to any one of claims 1 to 6, wherein, The M element is Zr, which exhibits peaks at positions 2θ = 32.30° ± 0.50° and 2θ = 33.70° ± 0.50° in the X-ray diffraction pattern of the halide oxide solid electrolyte. The intensity of the peak at 2θ = 32.30° ± 0.50° is I. A The intensity of the peak appearing at the position 2θ = 33.70° ± 0.50° is I. B Satisfying: I A / I B >1. The solid-state battery as described in claim 7, wherein, The crystalline phases of the halide oxide solid electrolyte include crystalline phase A and crystalline phase B, wherein crystalline phase A is composed of halide oxide solid electrolyte and crystalline phase B is composed of lithium oxide. The solid-state battery according to any one of claims 1 to 8, wherein, The Dv50 of the positive electrode active material is 2μm-6μm. The solid-state battery according to any one of claims 1 to 9, wherein, The solid-state battery is an all-solid-state battery. A method for preparing a solid-state battery, the solid-state battery comprising a positive electrode layer, the positive electrode layer comprising a positive electrode active material layer, the positive electrode active material layer comprising a mixture of positive electrode active materials and a solid electrolyte, the solid electrolyte comprising a halide oxide solid electrolyte; the preparation method includes the step of preparing the halide oxide solid electrolyte, the preparation method of the halide oxide solid electrolyte comprising: The halide oxide solid electrolyte is prepared by mixing a metal halide salt with an oxygen source; wherein the molar ratio of the metal halide salt to the oxygen source is ≥1 / 3, the metal halide salt contains an element M, the element M includes one or more of Zr, Fe, Al and Cr, and the molar ratio of halogen to oxygen in the halide oxide solid electrolyte is m / b, where m is the absolute value of the valence of the element M in the halide oxide solid electrolyte, and 0 < b ≤ 3. The preparation method according to claim 11, wherein, The preparation method of the halide oxide solid electrolyte includes one or more of the following conditions: (1) The molar ratio of the metal halide to the oxygen source is 1:(1-3); (2) The halogen contained in the metal halide includes one or more of F, Cl and Br; (3) The oxygen source includes one or more of lithium oxide and lithium hydroxide; (4) The metal halide and the oxygen source are mixed by ball milling; (5) The metal halide and the oxygen source are mixed by ball milling. The ball milling speed is 400rpm-700rpm, the time is 6h-12h, and the ball-to-material ratio is (20-60):

1. A positive electrode sheet includes a positive electrode active material layer comprising a mixture of positive electrode active materials and a solid electrolyte. The solid electrolyte includes a halide oxide solid electrolyte containing an element M, wherein the element M includes one or more of Zr, Fe, Al, and Cr. The molar ratio of halogen to oxygen in the halide oxide solid electrolyte is m / b. m is the absolute value of the valence of element M in the halide oxide solid electrolyte, 0 < b ≤ 3. The positive electrode sheet as described in claim 13, wherein, The positive electrode layer in a solid-state battery as described in any one of claims 2 to 9. An electrical device includes at least one of the solid-state battery as described in any one of claims 1 to 10 and the solid-state battery prepared by the method of preparing the solid-state battery as described in any one of claims 11 to 12.

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