Mixed solid electrolyte-coated positive electrode material, preparation method thereof, positive electrode sheet, solid-state battery, and electrical device

Abstract

The application provides a kind of mixed solid electrolyte wrapped positive electrode material and its preparation method, positive electrode sheet, solid-state battery and electrical equipment, it is related to new energy technology field.The mixed solid electrolyte wrapped positive electrode material provided by the application includes positive electrode material and mixed solid electrolyte wrapped on the surface of positive electrode material, and the mixed solid electrolyte includes oxide solid electrolyte, sulfide solid electrolyte and halide solid electrolyte.The application provides a kind of mixed solid electrolyte wrapped positive electrode material, oxide solid electrolyte provides mechanical performance, sulfide solid electrolyte provides ionic conductivity, and halide solid electrolyte provides stable interface, the structure stability and conductivity of positive electrode material can be effectively improved by the combination of three kinds of solid electrolytes, to improve the cycle stability of battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, in particular to a positive electrode material wrapped by a mixed solid-state electrolyte, a preparation method of the positive electrode material, a positive electrode sheet, a solid-state battery and an electrical equipment. BACKGROUND

[0002] With the increasing demand for clean energy worldwide, lithium-ion batteries, as an efficient and environmentally friendly energy storage method, are widely used in various electronic devices and electric vehicles. However, traditional lithium-ion batteries mainly use liquid electrolytes, which have potential safety hazards such as flammability and explosiveness. Therefore, developing safe and stable solid-state batteries has become an important research direction.

[0003] However, the existing solid-state battery has poor stability of the interface between the positive electrode material and the solid-state electrolyte during charging and discharging, which easily leads to capacity attenuation of the battery. SUMMARY

[0004] The present application aims to provide a positive electrode material wrapped by a mixed solid-state electrolyte, a preparation method of the positive electrode material, a positive electrode sheet, a solid-state battery and an electrical equipment, which aims to solve the problem of poor stability of the interface between the existing positive electrode material and the solid-state electrolyte, which easily leads to capacity attenuation of the solid-state battery.

[0005] To achieve the above purpose, the present application provides a positive electrode material wrapped by a mixed solid-state electrolyte, comprising: a positive electrode material and a mixed solid-state electrolyte wrapped on the surface of the positive electrode material, the mixed solid-state electrolyte comprising an oxide solid-state electrolyte, a sulfide solid-state electrolyte and a halide solid-state electrolyte.

[0006] In some embodiments, the particle size of the sulfide solid-state electrolyte is greater than the particle size of the halide solid-state electrolyte, and the particle size of the halide solid-state electrolyte is greater than the particle size of the oxide solid-state electrolyte.

[0007] Optionally, the particle size of the sulfide solid-state electrolyte: the particle size of the halide solid-state electrolyte: the particle size of the oxide solid-state electrolyte = (100-500):(30-70):(2-7).

[0008] In some embodiments, at least one of the following conditions is met:

[0009] A. The particle size of the sulfide solid-state electrolyte is 1-5 μm;

[0010] B. The particle size of the halide solid-state electrolyte is 300-700 nm;

[0011] C. The particle size of the oxide solid-state electrolyte is 20-70 nm.

[0012] In some embodiments, the mass of the sulfide solid-state electrolyte is greater than the sum of the mass of the oxide solid-state electrolyte and the mass of the halide solid-state electrolyte.

[0013] Optionally, the mass ratio of the oxide solid-state electrolyte, the sulfide solid-state electrolyte and the halide solid-state electrolyte is (0.1-1):10:(0.5-5).

[0014] In some embodiments, the oxide solid-state electrolyte comprises: Li 1+x Al x Ti 2-x (PO4)3, Li 7-x La3Zr 2- x M x O 12 (M = Ta, Nb) (0≤x<2), Li x La 2 / 3-x TiO3, LiAlO2, Li2ZrO3 and Li4Ti5O 12 any one or more of them;

[0015] In some embodiments, the sulfide solid-state electrolyte comprises: Li3PS4, 70Li2S·30P2S5, 80Li2S·20P2S5, 75Li2S·25P2S5, Li 10 GeP2S 12 and Li6PS5X (X = Cl, Br or I) any one or more of them;

[0016] In some embodiments, the halide solid-state electrolyte has a molecular formula of Li3AE6; wherein A is a trivalent metal, preferably A is In, Sc or Y, and E is at least one of F, Cl, Br;

[0017] In some embodiments, the positive electrode material comprises any one of lithium iron phosphate, lithium cobaltate, lithium manganate, lithium nickelate, binary material lithium nickel cobaltate, binary material lithium nickel manganate, ternary material lithium nickel cobalt manganate, ternary material lithium nickel cobalt aluminumate, lithium-rich manganese-based positive electrode material, and modified dopant of lithium iron phosphate, lithium cobaltate, lithium manganate, lithium nickelate, binary material lithium nickel cobaltate, binary material lithium nickel manganate, ternary material lithium nickel cobalt manganate, ternary material lithium nickel cobalt aluminumate and lithium-rich manganese-based positive electrode material.

[0018] In some embodiments, at least one of the following conditions is met:

[0019] A. The mass ratio of the sum of the mass of the oxide solid-state electrolyte, the sulfide solid-state electrolyte and the halide solid-state electrolyte to the mass of the positive electrode material is 1:2-2:1;

[0020] B. the room temperature ionic conductivity of the mixed solid-state electrolyte is 10 -4 -10 -2 S / cm.

[0021] The application further provides a preparation method of the mixed solid-state electrolyte-coated positive electrode material.

[0022] The oxide solid-state electrolyte, the sulfide solid-state electrolyte, and the halide solid-state electrolyte are mixed to obtain the mixed solid-state electrolyte.

[0023] The mixed solid-state electrolyte is coated on the surface of the positive electrode material by a ball milling method to obtain the mixed solid-state electrolyte-coated positive electrode material.

[0024] The application further provides a positive electrode sheet comprising the mixed solid-state electrolyte-coated positive electrode material.

[0025] The application further provides a solid-state battery comprising the mixed solid-state electrolyte-coated positive electrode material or the positive electrode sheet.

[0026] The application further provides an electrical equipment comprising the solid-state battery.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] The mixed solid-state electrolyte-coated positive electrode material provided by the application comprises a positive electrode material and a mixed solid-state electrolyte coated on the surface of the positive electrode material, and the mixed solid-state electrolyte comprises an oxide solid-state electrolyte, a sulfide solid-state electrolyte, and a halide solid-state electrolyte. The application designs a mixed solid-state electrolyte-coated positive electrode material, the oxide solid-state electrolyte provides mechanical properties, the sulfide solid-state electrolyte provides ionic conductivity, and the halide solid-state electrolyte provides a stable interface. The combination of the three solid-state electrolytes can effectively improve the structural stability and conductivity of the positive electrode material, thereby improving the cycle stability of the battery. Compared with the prior art, this method can more effectively solve the stability problem of the interface between the positive electrode material and the electrolyte and reduce the capacity attenuation of the battery. The mixed solid-state electrolyte has high conductivity and can improve the charging and discharging efficiency of the battery. Compared with the prior art, this method can more effectively solve the problems of low conductivity and poor interface of the solid-state electrolyte and improve the overall performance of the battery.

[0029] The sulfide solid-state full battery preparation process provided by the application is simple and low in cost, which is conducive to large-scale application. Compared with the prior art, this method can more effectively solve the problems of complex preparation process and high cost of the sulfide solid-state full battery, which is conducive to its practical application. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to illustrate the technical solutions of the embodiments of the present application more clearly, the drawings needed in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope of the present application.

[0031] Figure 1 Structure schematic diagram of an embodiment of the mixed solid-state electrolyte-coated positive electrode material of the present application;

[0032] Figure 2 Flowchart schematic diagram of the preparation method of the mixed solid-state electrolyte-coated positive electrode material of the present application;

[0033] Figure 3 SEM image of the mixed solid-state electrolyte-coated positive electrode material of Example 1. DETAILED DESCRIPTION

[0034] As used herein:

[0035] “Made from” is synonymous with “comprising.” The terms “comprising,” “including,” “having” or “with” or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0036] The transitional phrase “consisting of’ excludes any element, step, or ingredient not specified. If used in the claims, this phrase shall not be construed to mean that the noted elements or steps are essential to the practice of the claims. When the phrase “consisting of’ follows the transitional phrase “comprising a,” “including,” or “containing,” the elements or steps recited before the phrase are integral, and the phrase “consisting of’ does not exclude additional elements or steps.

[0037] When equivalent, concentration, or other values or parameters are expressed in a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, it should be understood that all ranges formed by any pair of an upper or preferred value and a lower or preferred value, whether or not the range is expressly disclosed, are specifically disclosed. For example, when the range “1-5” is disclosed, the described range should be interpreted to include the ranges “1-4,” “1-3,” “1-2,” “1-2 and 4-5,” “1-3 and 5,” etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include the end values and all integers and fractions within that range.

[0038] In these embodiments, the parts and percentages described are by mass, unless otherwise indicated.

[0039] "Quality parts" refers to the basic unit of measurement indicating the mass ratio relationship of multiple components, 1 part can represent any unit mass, such as 1g, 2.689g, etc. If we say that the mass of component A is a parts, and the mass of component B is b parts, it means that the mass ratio of component A to component B is a:b. Alternatively, the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that unlike the mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0040] "and / or" is used to indicate that one or both of the described cases can occur, for example, A and / or B includes (A and B) and (A or B).

[0041] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0042] The application provides a mixed solid-state electrolyte coated positive electrode material, comprising: a positive electrode material and a mixed solid-state electrolyte coated on the surface of the positive electrode material, the mixed solid-state electrolyte comprising an oxide solid-state electrolyte, a sulfide solid-state electrolyte and a halide solid-state electrolyte.

[0043] The application designs a mixed solid-state electrolyte coated positive electrode material, the oxide solid-state electrolyte provides mechanical properties, the sulfide solid-state electrolyte provides ionic conductivity, and the halide solid-state electrolyte provides stable interface. The combination of the three solid-state electrolytes can effectively improve the structural stability and electrical conductivity of the positive electrode material, thereby improving the cycle stability of the battery. Compared with the prior art, this method can more effectively solve the stability problem of the interface between the positive electrode material and the electrolyte, and reduce the capacity decay of the battery. The mixed solid-state electrolyte of the application has high conductivity, which can improve the charge and discharge efficiency of the battery. Compared with the prior art, this method can more effectively solve the problems of low conductivity and poor interface of the solid-state electrolyte, and improve the overall performance of the battery.

[0044] In some embodiments, the particle size of the sulfide solid-state electrolyte is greater than the particle size of the halide solid-state electrolyte, and the particle size of the halide solid-state electrolyte is greater than the particle size of the oxide solid-state electrolyte.

[0045] Please refer to Figure 1 , Figure 1FIG. 1 is a schematic diagram of an embodiment of a structure of a positive electrode material wrapped by a mixed solid-state electrolyte of the present application, Figure 1 In the example of FIG. 1, the positive electrode material is a ternary material lithium nickel cobalt manganese oxide (NCM particles), the sulfide solid-state electrolyte (sulfide) is a large particle, the halide solid-state electrolyte (halide) is a medium particle, and the oxide solid-state electrolyte (oxide) is a small particle.

[0046] The large particle of the sulfide solid-state electrolyte provides a fast ion transport channel to ensure the overall conductivity of the positive electrode. The large particle size can reduce the total interface area, reduce the interface resistance, and reduce the possibility of side reactions. The medium particle of the halide solid-state electrolyte acts as an intermediate layer, which can buffer the chemical mismatch between the sulfide solid-state electrolyte and the NCM positive electrode, reduce the interface side reaction, and provide an additional ion transport channel to maintain the interface conductivity. The small particle of the oxide solid-state electrolyte forms a protective layer to prevent the NCM positive electrode from directly contacting the sulfide solid-state electrolyte and triggering an interface decomposition reaction. The small particle has a large specific surface area, which can be uniformly distributed on the surface of the positive electrode to enhance the interface contact quality. The mechanical stability of the positive electrode is improved to avoid particle peeling or cracking caused by volume changes during the cycle process.

[0047] The synergistic effect of the large particle of the sulfide solid-state electrolyte, the medium particle of the halide solid-state electrolyte, and the small particle of the oxide solid-state electrolyte can optimize ion conduction. The large particle of the sulfide solid-state electrolyte provides a dominant ion transport channel, the medium particle of the halide solid-state electrolyte supplements the interface conductivity, and the small particle of the oxide solid-state electrolyte enhances the interface stability. The interface stability can also be improved. The halide solid-state electrolyte and the oxide solid-state electrolyte protect the interface between the sulfide solid-state electrolyte and the positive electrode in terms of chemistry and mechanics, respectively, to reduce interface decomposition and impedance growth. The cycle life can also be extended. Through the synergistic effect of the three materials, ion conduction is improved, and interface reactions are slowed down, and the capacity retention rate of the battery is improved.

[0048] Optionally, the particle size of the sulfide solid-state electrolyte: the particle size of the halide solid-state electrolyte: the particle size of the oxide solid-state electrolyte = (100-500):(30-70):(2-7).

[0049] In some embodiments, the particle size of the sulfide solid-state electrolyte is 1-5 μm, for example, it can be 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or any value between 1-5 μm.

[0050] In some embodiments, the particle size of the halide solid-state electrolyte is 300-700 nm, for example, can be 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, or any value between 300-700 nm.

[0051] In some embodiments, the particle size of the oxide solid-state electrolyte is 20-70 nm, for example, can be 20 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, or any value between 20-70 nm.

[0052] In some embodiments, the mass of the sulfide solid-state electrolyte is greater than the sum of the mass of the oxide solid-state electrolyte and the mass of the halide solid-state electrolyte. The sulfide solid-state electrolyte has high conductivity and good flexibility, and a large amount is needed to fill the interstitial space and optimize the ion conduction network; the halide solid-state electrolyte has moderate conductivity and flexibility, and a relatively small amount can balance the interface stability and conduction performance; the oxide solid-state electrolyte has low conductivity but strong chemical stability, and a small amount can meet the interface protection requirements, thereby maximizing the energy density of the battery.

[0053] In some embodiments, the mass ratio of the oxide solid-state electrolyte, the sulfide solid-state electrolyte, and the halide solid-state electrolyte is (0.1-1):10:(0.5-5), for example, can be 0.1:10:0.5, 0.2:10:1, 0.5:10:1, 0.6:10:2, 1:10:5, 1:10:1, or any ratio between (0.1-1):10:(0.5-5).

[0054] In some embodiments, the oxide solid-state electrolyte comprises: Li 1+x Al x Ti 2-x (PO4)3, Li 7-x La3Zr 2- x M x O 12 (M = Ta, Nb) (0≤x<2), Li x La 2 / 3-x TiO3, LiAlO2, Li2ZrO3, and Li4Ti5O 12 any one or more of them.

[0055] In some embodiments, the sulfide solid-state electrolyte comprises: Li3PS4, 70Li2S·30P2S5, 80Li2S·20P2S5, 75Li2S·25P2S5, Li 10 GeP2S12 Any one or more of Li6PS5X (X = Cl, Br, or I), Li7PS6, Li7PS5X (X = Cl, Br, or I), Li6PS5X (X = Cl, Br, or I), and Li3AE6.

[0056] In some embodiments, the halide solid-state electrolyte has a molecular formula of Li3AE6; wherein A is a trivalent metal, preferably, A is In, Sc, or Y, and E is at least one of F, Cl, and Br.

[0057] In some embodiments, the cathode material comprises any one of lithium iron phosphate, lithium cobaltate, lithium manganate, lithium nickelate, binary material lithium nickel cobaltate, binary material lithium nickel manganate, ternary material lithium nickel cobalt manganate, ternary material lithium nickel cobalt aluminumate, lithium-rich manganese-based cathode material, and modified dopant of lithium iron phosphate, lithium cobaltate, lithium manganate, lithium nickelate, binary material lithium nickel cobaltate, binary material lithium nickel manganate, ternary material lithium nickel cobalt manganate, ternary material lithium nickel cobalt aluminumate, and lithium-rich manganese-based cathode material.

[0058] In some embodiments, the mass ratio of the sum of the mass of the oxide solid-state electrolyte, the sulfide solid-state electrolyte, and the halide solid-state electrolyte to the mass of the cathode material is 1:2-2:1, which can be 1:2, 1:1, 3:2, 2:1, or any ratio between 1:2 and 2:1.

[0059] In some embodiments, the room temperature ionic conductivity of the mixed solid-state electrolyte is 10 -4 -10 -2 S / cm.

[0060] The application also provides a preparation method of the above-mentioned mixed solid-state electrolyte-coated cathode material, which comprises the following steps: Figure 2

[0061] S100: mixing an oxide solid-state electrolyte, a sulfide solid-state electrolyte, and a halide solid-state electrolyte to obtain a mixed solid-state electrolyte;

[0062] S200: coating the mixed solid-state electrolyte on the surface of a cathode material by a ball milling method to obtain a mixed solid-state electrolyte-coated cathode material.

[0063] The application also provides a cathode sheet comprising the above-mentioned mixed solid-state electrolyte-coated cathode material.

[0064] The application also provides a solid-state battery comprising the above-mentioned mixed solid-state electrolyte-coated cathode material or the above-mentioned cathode sheet.

[0065] The sulfide solid-state full battery provided by the application has a simple preparation process and low cost, and is conducive to large-scale application. Compared with the prior art, the method can more effectively solve the problems of complex preparation process and high cost of the sulfide solid-state full battery, and is conducive to the practical application.​

[0066] This application also provides an electrical device, including the aforementioned solid-state battery.

[0067] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0068] Example 1

[0069] This embodiment provides a positive electrode material encapsulated with a mixed solid electrolyte, the preparation method of which includes the following steps:

[0070] Step 1: Select a high-conductivity oxide solid electrolyte, Li7La3Zr2O 12 LLZO (50 nm particle size), sulfide solid electrolyte Li6PS5Cl (3 μm particle size), and halide solid electrolyte Li3InCl6 (500 nm particle size) were mixed to obtain a mixed solid electrolyte. The conductivity of this mixed solid electrolyte was 1.5 × 10⁻⁶. -3 S / cm can exist stably at room temperature.

[0071] Step 2: Preparation of the cathode material coated with a mixed solid electrolyte by ball milling. First, using lithium nickel cobalt manganese oxide (LCO) as the cathode material, the LCO and the mixed solid electrolyte from Step 1 were ball-milled at a mass ratio of 1:1 for 2 hours to obtain the cathode material coated with the mixed solid electrolyte of Example 1. Its SEM image is shown below. Figure 3 As shown.

[0072] This embodiment also provides a sulfide solid-state full battery, the preparation method of which includes the following steps:

[0073] The positive electrode material encapsulated with the mixed solid electrolyte of Example 1 was assembled together with a sulfide solid electrolyte (Li6PS5Cl) and a negative electrode material (Li metal) to form a sulfide solid-state full cell. Specifically, the positive electrode material, sulfide solid electrolyte, and negative electrode material were mixed at a mass ratio of 1:1:1, and then pressed under argon protection by hot pressing at 500°C and 500 MPa for 2 hours to obtain the sulfide solid-state full cell of Example 1.

[0074] The prepared sulfide solid-state full cell was subjected to performance test. The test conditions were as follows: charge-discharge test was carried out at room temperature at a current density of 0.1C, and the voltage range was 2.5-4.2V.

[0075] Example 2

[0076] The present example provides a mixed solid-state electrolyte-coated positive electrode material, and the preparation method thereof is different from that of Example 1 in that the oxide solid-state electrolyte of Example 2 is replaced by LATP, and the remaining steps are the same as those of Example 1.

[0077] Example 3

[0078] The present example provides a mixed solid-state electrolyte-coated positive electrode material, and the preparation method thereof is different from that of Example 1 in that Li3InCl6 is replaced by Li3ScCl6, and the remaining steps are the same as those of Example 1.

[0079] Example 4

[0080] The present example provides a mixed solid-state electrolyte-coated positive electrode material, and the preparation method thereof is different from that of Example 1 in that the mass of the sulfide solid-state electrolyte of Example 4 is 100 mg, and the remaining steps are the same as those of Example 1.

[0081] Example 5

[0082] The present example provides a mixed solid-state electrolyte-coated positive electrode material, and the preparation method thereof is different from that of Example 1 in that the mass of the halide solid-state electrolyte of Example 5 is 10 mg, and the remaining steps are the same as those of Example 1.

[0083] Example 6

[0084] The present example provides a mixed solid-state electrolyte-coated positive electrode material, and the preparation method thereof is different from that of Example 1 in that the particle size of the oxide solid-state electrolyte is 30 nm, the particle size of the sulfide solid-state electrolyte is 1 μm, and the particle size of the halide solid-state electrolyte is 300 nm, and the remaining steps are the same as those of Example 1.

[0085] Example 7

[0086] The present example provides a mixed solid-state electrolyte-coated positive electrode material, and the preparation method thereof is different from that of Example 1 in that the particle size of the oxide solid-state electrolyte is 70 nm, the particle size of the sulfide solid-state electrolyte is 5 μm, and the particle size of the halide solid-state electrolyte is 700 nm, and the remaining steps are the same as those of Example 1.

[0087] Comparative Example 1

[0088] The comparative example provides a solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the solid-state electrolyte of Comparative Example 1 only has an oxide solid-state electrolyte, and the remaining steps are the same as those of Example 1.

[0089] Comparative Example 2

[0090] The comparative example provides a solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the solid-state electrolyte of Comparative Example 2 only has a sulfide solid-state electrolyte, and the remaining steps are the same as those of Example 1.

[0091] Comparative Example 3

[0092] The comparative example provides a solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the solid-state electrolyte of Comparative Example 3 only has a halide solid-state electrolyte, and the remaining steps are the same as those of Example 1.

[0093] Comparative Example 4

[0094] The comparative example provides a solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the solid-state electrolyte of Comparative Example 4 only has an oxide solid-state electrolyte and a halide solid-state electrolyte, and the remaining steps are the same as those of Example 1.

[0095] Comparative Example 5

[0096] The comparative example provides a solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the solid-state electrolyte of Comparative Example 5 only has a halide solid-state electrolyte and a sulfide solid-state electrolyte, and the remaining steps are the same as those of Example 1.

[0097] Comparative Example 6

[0098] The comparative example provides a solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the solid-state electrolyte of Comparative Example 6 only has an oxide solid-state electrolyte and a sulfide solid-state electrolyte, and the remaining steps are the same as those of Example 1.

[0099] Comparative Example 7

[0100] The comparative example provides a solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the particle size of the oxide solid-state electrolyte is 80 nm, and the remaining steps are the same as those of Example 1.

[0101] Comparative Example 8

[0102] The comparative example provides a solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the particle size of the oxide solid-state electrolyte is 10 nm, and the remaining steps are the same as those of Example 1.

[0103] Comparative Example 9

[0104] This comparative example provides a mixed solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the particle size of the sulfide solid-state electrolyte is 6 pm, and the remaining steps are the same as those of Example 1.

[0105] Comparative Example 10

[0106] This comparative example provides a mixed solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the particle size of the sulfide solid-state electrolyte is 0.9 pm, and the remaining steps are the same as those of Example 1.

[0107] Comparative Example 11

[0108] This comparative example provides a mixed solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the particle size of the halide solid-state electrolyte is 800 nm, and the remaining steps are the same as those of Example 1.

[0109] Comparative Example 12

[0110] This comparative example provides a mixed solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the particle size of the halide solid-state electrolyte is 200 nm, and the remaining steps are the same as those of Example 1.

[0111] Comparative Example 13

[0112] This comparative example provides a mixed solid-state electrolyte-coated positive electrode material, the preparation method of which is different from that of Example 1 in that the halide solid-state electrolyte of Comparative Example 13 is replaced by Li3ZrCl7, and the remaining steps are the same as those of Example 1.

[0113] The test method for battery impedance is as follows:

[0114] 1. Grind the mixed solid-state electrolyte and weigh 100-200 mg into a solid-state battery test mold (Zhongke Wanyuan, model: JYGS1-10, inner diameter 10 mm), with stainless steel at both ends as blocking electrodes. Press at 3-6T for 1-10 min, maintain the pressure at 2.5-3.5T, use Bio-Logic equipment, set the frequency to 1 MHz-1 Hz, and measure the data;

[0115] 2. Fit the data according to the equivalent circuit model (such as the series resistance and capacitance model) to calculate the resistance value (R) of the electrolyte, which is usually the x-axis intercept in the high-frequency region;

[0116] 3. Take out the solid-state electrolyte, measure the thickness l and radius r of the solid-state electrolyte ceramic sheet with a screw micrometer, and calculate the room temperature ionic conductivity according to δ = l / Rπr 2 ​

[0117] Precautions: 1. Sample environment: Keep the test environment dry to avoid performance degradation of hygroscopic electrolytes (such as sulfides). 2. Signal stability: Ensure data consistency through multiple measurements.

[0118] The electrochemical performance of the sulfide solid-state full cells of each embodiment and comparative example is shown in Table 1.

[0119] Table 1. Electrochemical performance of sulfide solid-state full cells in each embodiment and comparative example.

[0120]

[0121]

[0122] As shown in Table 1, Examples 1-7 and Comparative Examples 7-12, which used a mixture of three solid electrolytes to coat the surface of the cathode material, showed a significant reduction in battery impedance after 100 cycles compared to Comparative Examples 1-6, which used only one or two solid electrolytes. This indicates that the cathode material has high conductivity. Furthermore, in Examples 1-7, the three solid electrolytes, when used in appropriate proportions and particle sizes, can improve the structural stability of the cathode material, resulting in higher capacity retention rates after 100 cycles compared to Comparative Examples 7-12. Comparative Example 13 shows that the halide solid electrolyte Li3ZrCl7 used in Comparative Example 13 did not significantly contribute to the stability of the cathode material. This is because Li3ZrCl7 has low ionic conductivity and poor electrochemical stability.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0124] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A hybrid solid-state electrolyte- wrapped cathode material, characterized in that, The positive electrode material and the mixed solid-state electrolyte wrapped on the surface of the positive electrode material, the mixed solid-state electrolyte comprising an oxide solid-state electrolyte, a sulfide solid-state electrolyte and a halide solid-state electrolyte; The particle size of the sulfide solid-state electrolyte is 1-5 µm; The particle size of the halide solid-state electrolyte is 300-700 nm; The particle size of the oxide solid-state electrolyte is 20-70 nm; The molecular formula of the halide solid-state electrolyte is Li3AE6; wherein A is In, Sc or Y, and E is at least one of F, Cl and Br. The mass of the sulfide solid-state electrolyte is greater than the sum of the mass of the oxide solid-state electrolyte and the mass of the halide solid-state electrolyte.

2. The hybrid solid-state electrolyte-wrapped cathode material of claim 1, wherein, The mass ratio of the oxide solid-state electrolyte, the sulfide solid-state electrolyte and the halide solid-state electrolyte is (0.1-1):

3. The hybrid solid-state electrolyte-wrapped cathode material of claim 1, wherein, At least one of the following conditions is met: 10：（0.5~5）。 4. The hybrid solid-state electrolyte-wrapped cathode material of claim 1, wherein, C. The positive electrode material comprises any one of lithium iron phosphate, lithium cobaltate, lithium manganate, lithium nickelate, binary material lithium nickel cobaltate, binary material lithium nickel manganate, ternary material lithium nickel cobalt manganate, ternary material lithium nickel cobalt aluminumate, modified doped lithium iron phosphate, modified doped lithium cobaltate, modified doped lithium manganate, modified doped lithium nickelate, modified doped binary material lithium nickel cobaltate, modified doped binary material lithium nickel manganate, modified doped ternary material lithium nickel cobalt manganate, and modified doped ternary material lithium nickel cobalt aluminumate. A. the oxide solid-state electrolyte comprises: Li 1+x Al x Ti 2-x (PO4)3, Li 7-x La3Zr 2-x M x O 12 , Li x La 2 / （3-x） TiO3, LiAlO2, Li2ZrO3, and Li4Ti5O 12 ; wherein 0≤x<2, and M is Ta or Nb; B. the sulfide solid-state electrolyte comprises: Li3PS4, 70Li2S-30P2S5, 80Li2S-20P2S5, 75Li2S-25P2S5, Li 10 GeP2S 12 and any one or more of Li6PS5X; wherein X is CI, Br, or I. At least one of the following conditions is met:

5. The hybrid solid-state electrolyte-wrapped cathode material of any one of claims 1 to 4, wherein the solid-state electrolyte is a lithium ion-conducting solid-state electrolyte. A. The mass ratio of the sum of the mass of the oxide solid-state electrolyte, the sulfide solid-state electrolyte and the halide solid-state electrolyte to the mass of the positive electrode material is 1:2-2:

1. The positive electrode material and the mixed solid-state electrolyte wrapped on the surface of the positive electrode material, the mixed solid-state electrolyte comprising an oxide solid-state electrolyte, a sulfide solid-state electrolyte and a halide solid-state electrolyte; B. The mixed solid-state electrolyte has a room temperature ionic conductivity of 10 -4 -10 -2 S / cm.

6. A method of producing a mixed solid-state electrolyte-coated positive electrode material according to any one of claims 1 to 5, characterized by, Mixing the oxide solid-state electrolyte, the sulfide solid-state electrolyte and the halide solid-state electrolyte to obtain a mixed solid-state electrolyte; Wrapping the mixed solid-state electrolyte on the surface of the positive electrode material by a ball milling method to obtain the mixed solid-state electrolyte wrapped positive electrode material. The mixed solid-state electrolyte wrapped positive electrode material of any one of claims 1-5.

7. A positive electrode sheet characterized by comprising: The mixed solid-state electrolyte wrapped positive electrode material of any one of claims 1-5, or the positive electrode sheet of claim 7.

8. A solid state battery, characterized by The solid-state battery of claim 8.

9. An electrical device, comprising: ​

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