Positive electrode materials and their preparation methods, electrode components, lithium-ion batteries and electrical devices

Abstract

This invention relates to a positive electrode material, its preparation method, an electrode assembly, a lithium-ion battery, and an electrical device. The positive electrode material includes an inner core and a coating layer covering the surface of the inner core; the inner core contains a positive electrode active material for a lithium-ion battery, the coating layer contains halloysite material, and the coating layer is further coated with a conductive polymer material. This positive electrode material exhibits high cycle stability.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a positive electrode material and its preparation method, an electrode assembly, a lithium-ion battery, and an electrical device. Background Technology

[0002] Halloysite, due to its unique nanotube structure, has a large specific surface area and porosity, and is widely used in ceramics, medicine, nanoreactors, nanotemplates, polymer fillers and other fields.

[0003] Other methods extend halloysite into the electrical field, primarily by combining it with conductive materials to prepare electrode materials and supercapacitor materials. For example, one method involves a positive electrode sheet for a lithium-ion battery containing halloysite. Halloysite is blended with the positive electrode active material to prepare a positive electrode slurry, mainly utilizing the nanotube structure of halloysite to form a three-dimensional interconnected structure, thereby improving the battery's capacity and cycle stability. However, the lithium-ion battery prepared by this method only retains 75%–85% of its capacity after 200 cycles, and its cycle stability needs further improvement. Summary of the Invention

[0004] Based on this, the present invention provides a cathode material with high cycle stability and a method for preparing the same, including an electrode assembly, a lithium-ion battery, and an electrical device thereof.

[0005] In a first aspect, the present invention provides a positive electrode material, comprising an inner core and a coating layer covering the surface of the inner core;

[0006] The core contains a positive electrode active material for a lithium-ion battery, the coating layer contains halloysite material, and a conductive polymer material is attached to the coating layer.

[0007] In one embodiment, the halloysite material comprises 0.1% to 4% of the core by mass.

[0008] Optionally, the halloysite material comprises 0.1% to 3% by mass.

[0009] Further optionally, the halloysite material is 1.5% to 2% by mass.

[0010] In one embodiment, the halloysite material comprises a nanotube structure that satisfies at least one of the following characteristics:

[0011] (1) The length is ≤0.05μm;

[0012] (2) The outer diameter is 30nm~70nm;

[0013] (3) The inner diameter is 5nm to 20nm.

[0014] In one embodiment, the conductive polymer material is 0.3% to 5% of the mass of the core, or alternatively, 2% to 5% of the mass of the conductive polymer material.

[0015] In one embodiment, the conductive polymer material includes one or more of polyethylene glycol, polyethylene, polypropylene, polyacetylene, polypyrrole, polythiophene, polyaniline, and derivatives of the foregoing materials.

[0016] In one embodiment, the positive electrode active material for the lithium-ion battery includes one or both of high-nickel ternary materials and lithium-rich materials.

[0017] Optionally, the chemical formula of the high-nickel ternary material is LiNi. x Co y Mn 1-x-y O2, where x≥0.5, 0≤y≤0.2;

[0018] Optionally, the chemical formula of the lithium-rich material is nLi2MnO3·(1-n)LiMO2, where 0≤n≤1 and M is one or more of Ni, Co and Mn.

[0019] A second aspect of the present invention provides a method for preparing a positive electrode material, comprising the following steps:

[0020] A first product is prepared by mixing an inner core material, a coating material, and a first solvent, removing the first solvent, and performing a first sintering; the inner core material contains a positive electrode active material for lithium-ion batteries, and the coating material contains halloysite material.

[0021] The first product is mixed with a second solvent and monomers of a conductive polymer material, and the monomers of the conductive polymer material are subjected to in-situ polymerization on the first product to generate a conductive polymer material. The second solvent is then removed to prepare the second product.

[0022] The second product is sintered a second time to prepare the cathode material.

[0023] In one embodiment, the process of shortening the halloysite material is included before mixing the core material, the coating material, and the first solvent.

[0024] In one embodiment, the method for shortening the tube is ultrasonic treatment;

[0025] Optionally, the conditions for ultrasonic treatment include: ultrasonic power of 800W to 1200W and time of 2h to 5h. In one embodiment, the conditions for the first sintering include at least one of (1) to (2):

[0026] (1) The temperature of the first sintering is 500℃~800℃; optionally, the temperature of the first sintering is 600℃~750℃; optionally, the heating rate to the temperature of the first sintering is 1~10℃ / min.

[0027] (2) The first sintering time is 90 min to 360 min; optionally, the first sintering time is 180 min to 300 min.

[0028] In one embodiment, the conditions for the second sintering include at least one of (1) to (2):

[0029] (1) The temperature of the second sintering is 250℃~380℃, and optionally, the temperature of the second sintering is 300℃~360℃; optionally, the heating rate to the temperature of the second sintering is 1~10℃ / min;

[0030] (2) The second sintering time is 30 min to 240 min; optionally, the second sintering time is 60 min to 180 min.

[0031] In one embodiment, the conditions for in-situ polymerization include at least one of (1) to (3):

[0032] (1) The temperature is 0~5℃;

[0033] (2) The time is 5h to 10h;

[0034] (3) The process is carried out under the induction of an inducing agent. Optionally, the inducing agent includes one or more of water-soluble redox agents and peroxides. More preferably, the inducing agent includes one or two of hydrogen peroxide and oxalic acid.

[0035] In one embodiment, the method for removing the first solvent or the second solvent is vacuum drying or vacuum freeze drying; optionally, the temperature of vacuum drying is 100-150°C and the time is 10-20h; optionally, the temperature of vacuum freeze drying is -50-30°C and the time is 10-20h.

[0036] In one embodiment, the halloysite material is 0.1% to 4% of the mass of the core material, optionally 0.1% to 3% of the mass of the halloysite material, and further optionally 1.5% to 2% of the mass of the halloysite material.

[0037] In one embodiment, the halloysite material comprises a nanotube structure that satisfies at least one of the following characteristics:

[0038] (1) The length is ≤0.05μm;

[0039] (2) The outer diameter is 30nm~70nm;

[0040] (3) The inner diameter is 5nm to 20nm.

[0041] In one embodiment, the conductive polymer material comprises 0.3% to 5% of the core material by mass; alternatively, the conductive polymer material comprises 2% to 5% by mass.

[0042] In one embodiment, the conductive polymer material includes one or more of polyethylene glycol, polyethylene, polypropylene, polyacetylene, polypyrrole, polythiophene, polyaniline, and derivatives of the foregoing materials.

[0043] In one embodiment, the positive electrode active material for the lithium-ion battery includes one or both of high-nickel ternary materials and lithium-rich materials.

[0044] Optionally, the chemical formula of the high-nickel ternary material is LiNi. x Co y Mn 1-x-y O2, where x≥0.5, 0≤y≤0.2;

[0045] Optionally, the lithium-rich material has the chemical formula nLi2MnO3·(1-n)LiMO2, where 0≤n≤1 and M is one or more of Ni, Co and Mn.

[0046] A third aspect of the present invention provides a positive electrode sheet, comprising a positive current collector and a positive active material layer;

[0047] The positive electrode active material layer is located on the surface of the positive electrode current collector, and the material of the positive electrode active material layer includes the positive electrode material as described in the first aspect or the positive electrode material prepared by the preparation method described in the second aspect.

[0048] A fourth aspect of the present invention provides an electrode assembly comprising a negative electrode, a separator, and a positive electrode as described in the third aspect, all stacked together.

[0049] A fifth aspect of the present invention provides a lithium-ion battery, comprising a casing, an electrolyte, and an electrode assembly as described in the fourth aspect; the electrolyte and the electrode assembly are housed within the casing.

[0050] A sixth aspect of the present invention provides a battery module comprising the lithium-ion battery described in the fifth aspect.

[0051] A seventh aspect of the present invention provides a battery pack comprising the battery module described in the sixth aspect.

[0052] An eighth aspect of the present invention provides an electrical device comprising one or more of the lithium-ion battery described in the fifth aspect, the battery module described in the sixth aspect, or the battery pack described in the seventh aspect.

[0053] Invention Effects

[0054] The aforementioned cathode material uses the cathode active material for lithium-ion batteries as its core and has a coating layer containing halloysite material on its surface. This forms a physical protective layer for the core, and during cycling, the halloysite material can also react with the electrolyte to form an interface film. This reduces the destruction of the surface phase change structure of the lithium-ion battery cathode active material during cycling, reduces the dissolution of metal ions, and reduces side reactions. As a result, it more effectively improves the cycle stability of lithium-ion batteries than traditional methods, and still has a high cycle capacity retention rate under high temperature and long-term storage conditions. It is particularly suitable for high-voltage platform cathode materials, such as high-nickel materials and lithium-rich materials.

[0055] Meanwhile, halloysite materials can also act as templates. By compositing conductive polymer materials on its surface, which has a large specific surface area and porosity, the influence of the introduction of the coating layer on the conductivity of the positive electrode active material of lithium-ion batteries can be avoided, and the rate performance of the battery can be further improved. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of a lithium-ion battery according to an embodiment of the present invention;

[0057] Figure 2 for Figure 1 An exploded view of a lithium-ion battery according to an embodiment of the present invention is shown.

[0058] Figure 3 This is a schematic diagram of a battery module according to one embodiment of the present invention;

[0059] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of the present invention;

[0060] Figure 5 for Figure 4 An exploded view of a battery pack according to an embodiment of the present invention is shown.

[0061] Figure 6 This is a schematic diagram of an electrical device using a lithium-ion battery as a power source according to an embodiment of the present invention.

[0062] Explanation of reference numerals in the attached figures:

[0063] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Lithium-ion battery; 51 Casing; 52 Electrode assembly; 53 Cover plate; 6 Electrical device. Detailed Implementation

[0064] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the positive electrode material, its preparation method, electrode assembly, lithium-ion battery, and power application device of the present invention. However, unnecessary detailed descriptions 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 the invention and are not intended to limit the subject matter of the claims.

[0065] The "range" disclosed in this invention is 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 and can be arbitrarily combined; 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 specific parameters, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this invention, unless otherwise stated, the numerical range "a–b" 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 "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0066] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0067] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0068] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method 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, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method 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.

[0069] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0070] Unless otherwise specified, the term "or" is inclusive in this invention. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0071] Unless otherwise specified, in this invention, "one or more" refers to any one, two, or more of the listed items. "Several" refers to any two or more.

[0072] Unless otherwise specified, in this invention, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" 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, terms such as "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0073] This invention provides a positive electrode material, including an inner core and a coating layer covering the surface of the inner core. The inner core contains a positive electrode active material for lithium-ion batteries, the coating layer contains halloysite material, and a conductive polymer material is attached to the coating layer.

[0074] Understandably, halloysite is a silicate mineral, also known as hydrous kaolinite, with a chemical composition similar to kaolinite. The main difference lies in their crystal structures: halloysite has a tubular structure, while kaolinite has a platy structure. Therefore, in one example, the halloysite material contains a tubular structure.

[0075] In one example, the halloysite material comprises 0.1% to 4% of the core mass. Specifically, the halloysite material comprises, but is not limited to, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, and 4% of the core mass. Further, the halloysite material comprises 0.1% to 3% of the core mass. Even further, the halloysite material comprises 1.5% to 2% of the core mass.

[0076] In one example, the halloysite material comprises a nanotube structure. Furthermore, the nanotube structure satisfies at least one of the following characteristics:

[0077] (1) The length is ≤0.05μm;

[0078] (2) The outer diameter is 30nm~70nm;

[0079] (3) The inner diameter is 5nm to 20nm.

[0080] Understandably, when the length of the nanotube structure contained in the halloysite material is greater than 0.05 μm, for example, 0.05 μm to 0.1 μm, the halloysite material can be shortened. This ensures that the nanotube structure of the halloysite material has a uniform length and is easier to coat onto the surface of the positive electrode active material of the lithium battery.

[0081] In one example, the mass percentage of the conductive polymer material relative to the mass of the core is 0.3% to 5%. Specifically, the mass percentage of the conductive polymer material relative to the mass of the core includes, but is not limited to: 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%. Further, the mass percentage of the conductive polymer material relative to the mass of the core is 2% to 5%.

[0082] In one example, the conductive polymer material includes one or more of polyethylene glycol, polyethylene, polypropylene, polyacetylene, polypyrrole, polythiophene, polyaniline, and derivatives of the aforementioned materials.

[0083] Understandably, the positive electrode active material used in lithium-ion batteries is not particularly limited, and any positive electrode active material known in the art for lithium-ion batteries may be used. As an example, the positive electrode active material may include one or more of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present invention is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for lithium-ion batteries may also be used. These lithium-ion battery 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, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as 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 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 One or more of the following: O2) and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0084] In one example, the positive electrode active material used in the lithium-ion battery is a high-voltage platform positive electrode material. Further, the positive electrode active material used in the lithium-ion battery includes one or both of high-nickel ternary materials and lithium-rich materials. Specifically, the chemical formula of the high-nickel ternary material may be LiNi. x Co y Mn1-x-y O2, where x≥0.5, 0≤y≤0.2. The chemical formula of the lithium-rich material can be nLi2MnO3·(1-n)LiMO2, where 0≤n≤1, and M is one or more of Ni, Co and Mn.

[0085] The present invention also provides a method for preparing a positive electrode material, comprising the following steps:

[0086] (a) Mix the core material, the coating material and the first solvent, remove the first solvent, and perform a first sintering to prepare the first product; the core material contains a positive electrode active material and the coating material contains halloysite material.

[0087] (b) Mix the first product with the second solvent and the monomer of the conductive polymer material, and allow the monomer of the conductive polymer material to undergo in-situ polymerization on the first product to generate the conductive polymer material. Remove the second solvent to prepare the second product.

[0088] (c) The second product is sintered a second time to prepare the cathode material.

[0089] Specifically, in step (a):

[0090] Without limitation, in this step, the coating material is formed by the first sintering to coat the surface of the core material, forming a core@coating structure.

[0091] In one example, when the halloysite material contains nanotube structures with a length greater than 0.05 μm, for example, 0.05 μm to 0.1 μm, a step of shortening the halloysite material is included before mixing the core material, the coating material, and the first solvent. This ensures that the nanotube structures of the halloysite material have uniform length and are more easily coated onto the surface of the positive electrode active material of the lithium battery. Specifically, the shortening step ensures that the length of the nanotube structures contained in the halloysite material is ≤0.05 μm.

[0092] In one example, the method for shortening the tube is ultrasonic treatment. Optionally, the conditions for ultrasonic treatment include: ultrasonic power of 800W to 1200W and time of 2h to 5h.

[0093] In one example, the halloysite material comprises 0.1% to 4% of the core material by mass. Specifically, the halloysite material comprises, but is not limited to, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, and 4% of the core material by mass. Further, the halloysite material comprises 0.1% to 3% of the core material by mass. Even further, the halloysite material comprises 1.5% to 2% of the core material by mass.

[0094] In one example, halloysite material comprises a nanotube structure that satisfies at least one of the following characteristics:

[0095] (1) The length is ≤0.05μm;

[0096] (2) The outer diameter is 30nm~70nm;

[0097] (3) The inner diameter is 5nm to 20nm.

[0098] Understandably, the positive electrode active material used in lithium-ion batteries is not particularly limited, and any positive electrode active material known in the art for lithium-ion batteries may be used. As an example, the positive electrode active material may include one or more of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present invention is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for lithium-ion batteries may also be used. These lithium-ion battery 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, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as 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 LiNi0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 One or more of the following: O2) and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0099] In one example, the positive electrode active material used in the lithium-ion battery is a high-voltage platform positive electrode material. Further, the positive electrode active material used in the lithium-ion battery includes one or both of high-nickel ternary materials and lithium-rich materials. Specifically, the chemical formula of the high-nickel ternary material may be LiNi. x Co y Mn 1-x-y O2, where x≥0.5, 0≤y≤0.2. The chemical formula of the lithium-rich material can be nLi2MnO3·(1-n)LiMO2, where 0≤n≤1, and M is one or more of Ni, Co and Mn.

[0100] In one example, the first solvent is an organic solvent. Understandably, the type of organic solvent is not particularly limited, and examples include one or more of ethanol, ethylene glycol, and acetone.

[0101] In one example, the mixing conditions included: room temperature and a time of 5 to 12 hours.

[0102] In one example, the temperature for the first sintering is 500℃ to 800℃. Specifically, the temperature for the first sintering includes, but is not limited to: 500℃, 550℃, 580℃, 600℃, 620℃, 650℃, 700℃, 730℃, 750℃, 780℃, and 800℃. Further, the temperature for the first sintering is 600℃ to 750℃.

[0103] In one example, the heating rate to the temperature of the first sintering is 1 to 10 °C / min. Specifically, the heating rate to the temperature of the first sintering includes, but is not limited to: 1 °C / min, 2 °C / min, 3 °C / min, 4 °C / min, 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min, and 10 °C / min.

[0104] In one example, the first sintering time is 90 min to 360 min. Specifically, the first sintering temperature includes, but is not limited to: 90 min, 120 min, 180 min, 210 min, 240 min, 250 min, 260 min, 270 min, 280 min, 290 min, 300 min, 320 min, and 360 min.

[0105] In one example, after the first sintering, the temperature was allowed to drop naturally to room temperature.

[0106] In one example, the method for removing the first solvent is vacuum drying or vacuum freeze-drying. Vacuum drying is performed at a temperature of 100–150°C for 10–20 hours; vacuum freeze-drying is performed at a temperature of -50–-30°C for 10–20 hours. "Vacuum" can be provided using existing equipment in the art, and the vacuum level is not limited to 50 Pa–150 Pa.

[0107] Specifically, in step (b):

[0108] Without limitation, in this step, the monomers of the conductive polymer material are polymerized in situ on the first product to generate a conductive polymer material attached to the coating layer.

[0109] In one example, the conductive polymer material comprises 0.3% to 5% of the core material by mass. Specifically, the percentage of the conductive polymer material by mass, including but not limited to: 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%. Further, the percentage of the conductive polymer material by mass, including but not limited to: 2% to 5%.

[0110] In one example, the conductive polymer material includes one or more of polyethylene glycol, polyethylene, polypropylene, polyacetylene, polypyrrole, polythiophene, polyaniline, and derivatives of the aforementioned materials. Accordingly, the monomers of the conductive polymer material include one or more of ethylene glycol, ethylene, propylene, acetylene, pyrrole, thiophene, aniline, and derivatives of the aforementioned materials.

[0111] In one example, the second solvent is an organic solvent. It is understood that the type of organic solvent is not particularly limited, and examples include one or more of ethanol, ethylene glycol, and acetone. It is understood that the first solvent and the second solvent may be the same or different. In one example, the first solvent and the second solvent are the same.

[0112] In one example, the in-situ polymerization temperature was 0–5 °C. Furthermore, the in-situ polymerization was carried out under ice-water bath conditions.

[0113] In one example, the in-situ polymerization time was 5 to 10 hours.

[0114] In one example, in-situ polymerization is carried out under the induction of an inducing agent. Without limitation, the inducing agent includes one or more of water-soluble redox agents and peroxides; specifically, the inducing agent includes one or both of hydrogen peroxide and oxalic acid.

[0115] In one example, the method for removing the second solvent is vacuum drying or vacuum freeze-drying. Vacuum drying is performed at a temperature of 100–150°C for 10–20 hours; vacuum freeze-drying is performed at a temperature of -50–-30°C for 10–20 hours. "Vacuum" can be provided using existing equipment in the art, and the vacuum level is not limited to 50–150 Pa.

[0116] Specifically, in step (c):

[0117] Without limitation, in this step, the conductive polymer material prepared by in-situ polymerization is tightly adhered to the coating layer by a second sintering.

[0118] In one example, the temperature for the second sintering is 250℃ to 380℃. Specifically, the temperatures for the second sintering include, but are not limited to: 250℃, 270℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, and 380℃. Further, the temperature for the second sintering is 300℃ to 360℃.

[0119] In one example, the heating rate to the second sintering temperature is 1–10 °C / min. Specifically, the heating rate to the second sintering temperature includes, but is not limited to: 1 °C / min, 2 °C / min, 3 °C / min, 4 °C / min, 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min, and 10 °C / min.

[0120] In one example, the second sintering time is 30 min to 240 min. Specifically, the temperature of the first sintering includes, but is not limited to: 30 min, 50 min, 60 min, 70 min, 90 min, 120 min, 180 min, 210 min, and 240 min.

[0121] In one example, after the second sintering was completed, the temperature was allowed to cool naturally to room temperature.

[0122] In addition, the present invention provides a positive electrode sheet, including a positive current collector and a positive active material layer; the positive active material layer is located on the surface of the positive current collector, and the material of the positive active material layer includes the positive electrode material as described above or the positive electrode material prepared by the preparation method as described above.

[0123] Without limitation, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0124] Without limitation, the positive electrode current collector can be a metal foil or a composite current collector. For example, aluminum foil can be used as the metal foil. 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. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0125] In one example, the positive electrode active material layer may optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0126] In one example, the positive electrode active material layer may optionally include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0127] In one example, the positive electrode sheet can be prepared by dispersing the components used to prepare the positive electrode sheet, such as the positive electrode material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0128] The present invention also provides an electrode assembly, comprising a negative electrode, a separator, and a positive electrode as described in the third aspect, which are stacked together.

[0129] Without limitation, the negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, the negative active material layer including a negative active material.

[0130] In one example, the negative electrode current collector has two surfaces opposite 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.

[0131] In one example, the negative electrode current collector can be a metal foil or a composite current collector. For example, copper foil can be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0132] In one example, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the invention is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0133] In one example, the negative electrode active material layer may optionally include a binder. The binder may be selected from at least one 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).

[0134] In one example, the negative electrode active material layer may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0135] In one example, the negative electrode active material layer may also optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0136] In one example, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0137] Understandably, the present invention does not impose any particular restrictions on the type of separator membrane, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0138] In one example, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0139] In one example, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding process or a stacking process.

[0140] The present invention also provides a lithium-ion battery, including a casing, an electrolyte, and an electrode assembly as described above; the electrolyte and the electrode assembly are housed within the casing.

[0141] Understandably, during battery charging and discharging, active ions repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, primarily prevents short circuits between the positive and negative electrodes while allowing ions to pass through.

[0142] Understandably, this invention does not impose specific limitations on the type of electrolyte, which can be selected according to requirements. For example, the electrolyte can be liquid, gel, or completely solid.

[0143] In one example, the electrolyte is an electrolyte solution. The electrolyte solution consists of an electrolyte salt and a solvent.

[0144] In one example, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0145] In one example, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0146] In one example, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0147] Additionally, lithium-ion batteries may include an outer packaging. This outer packaging can be used to encapsulate the aforementioned electrode components and electrolyte.

[0148] In one example, the outer packaging of a lithium-ion battery can be a rigid shell, such as a hard plastic shell, aluminum shell, or steel shell. The outer packaging of a lithium-ion battery can also be a soft pack, such as a pouch. The material of the soft pack can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0149] This invention does not impose any particular limitation on the shape of the lithium-ion battery; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 1 This is an example of a square-structured lithium-ion battery 5.

[0150] In some of these embodiments, reference is made to Figure 2 The outer packaging may include a housing 51 and a cover 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 53 can be placed over the opening to close the receiving cavity. Positive electrode sheets, negative electrode sheets, and a separator can be formed into an electrode assembly 52 through a winding process or a stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The lithium-ion battery 5 may contain one or more electrode assemblies 52, which can be selected by those skilled in the art according to specific practical needs.

[0151] In some embodiments, lithium-ion batteries can be assembled into battery modules, and the number of lithium-ion batteries contained in a battery module can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery module.

[0152] Figure 3 This is battery module 4, used as an example. (See reference...) Figure 3In battery module 4, multiple lithium-ion batteries 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, the multiple lithium-ion batteries 5 can be fixed in place using fasteners.

[0153] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple lithium-ion batteries 5 are housed.

[0154] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0155] Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5 The battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0156] In addition, the present invention also provides an electrical device, which includes at least one of a lithium-ion battery, a battery module, or a battery pack provided by the present invention. The lithium-ion battery, battery module, or battery pack can be used as a power source for the electrical device or as an energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Mobile devices may include, for example, mobile phones, laptops, etc.; electric vehicles may include, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc., but are not limited to these.

[0157] As an electrical device, lithium-ion batteries, battery modules, or battery packs can be selected according to their usage requirements.

[0158] Figure 6 Here is 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 lithium-ion batteries for this electrical device, a battery pack or battery module can be used.

[0159] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use lithium-ion batteries as their power source.

[0160] Example

[0161] The following describes embodiments of the present invention. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0162] The halloysite material used in the embodiments has a nanotube structure with a length of 0.05μm to 0.1μm, an outer diameter of 30nm to 70nm, and an inner diameter of 5nm to 20nm.

[0163] The abbreviations involved in this invention are explained as follows:

[0164] HNTs: Halloysite materials;

[0165] PPy: Polypyrrole;

[0166] PEDOT: A polymer of 3,4-ethylenedioxythiophene monomer;

[0167] PEG: Polyethylene glycol.

[0168] The preparation method of the positive electrode active material used in the examples is as follows:

[0169] (1) HNTs were treated with ultrasonic power of 1000W for 5h to make the length of the HNT nanotube structure ≤0.05μm;

[0170] (2) Mix the HNTs treated in step (1) with the active material in ethanol according to the proportion in Table 1 and stir for 10 h. Then, perform vacuum drying to remove the solvent. The drying temperature is 120℃, the vacuum degree is 100Pa, and the time is 12 h. Then, sinter according to the temperature in Table 1. The heating rate is 5℃ / min. After holding the temperature for 300 min, let it cool down naturally to room temperature.

[0171] (3) Place the material prepared in step (2) in ethanol, add the monomer of the conductive polymer material dropwise in an ice-water bath (0 to -5℃) according to the proportion in Table 1, and add 1 / 2 of the monomer mass of oxalic acid as an inducer to polymerize in situ on the surface of the active material for 8 hours.

[0172] (4) The product obtained in step (3) was vacuum freeze-dried at -40℃ for 12h to remove the solvent. The mixed material was ground and placed in a quartz boat. It was sintered according to the temperature in Table 1. The heating rate was 5℃ / min. After the temperature was maintained for 2h, it was naturally cooled to room temperature to obtain the active material@template material / polymer material.

[0173] The positive electrode active materials used in the comparative examples were LiNi0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811) and Li-rich, without additional treatment or only HNT coating, without the addition of conductive polymer materials.

[0174] The preparation methods of the lithium-ion batteries in the examples and comparative examples are as follows:

[0175] (1) Preparation of negative electrode sheet

[0176] The negative electrode active material graphite, conductive agent acetylene black, binder styrene-butadiene rubber, and thickener sodium carboxymethyl cellulose are mixed in a weight ratio of graphite:acetylene black:styrene-butadiene rubber:sodium carboxymethyl cellulose = 95:2:2:1. An appropriate amount of deionized water is added and the mixture is stirred thoroughly to form a uniform negative electrode slurry. The slurry is coated onto the negative electrode current collector copper foil, dried, and cold-pressed to obtain the negative electrode sheet.

[0177] (2) Preparation of positive electrode sheet

[0178] The corresponding positive electrode active material, conductive agent acetylene black and binder polyvinylidene fluoride are mixed in a weight ratio of 96:2:2. N-methylpyrrolidone is used as a solvent. After thorough grinding and stirring, a uniform positive electrode slurry is formed. The slurry is coated on the positive electrode current collector aluminum foil, dried and cold pressed to obtain the positive electrode sheet.

[0179] (3) Battery manufacturing

[0180] The positive electrode, separator (PE porous polymer film), and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. Then, they are wound to obtain a bare cell. The bare cell is placed in an outer packaging foil, and the prepared electrolyte is injected into the dried battery. Then, the battery is obtained through vacuum sealing, settling, formation, and shaping processes.

[0181] Table 1

[0182]

[0183] Note: The percentage is based on the mass percentage of the active material.

[0184] Test case

[0185] (1) Battery 25 / 45℃ Cyclic Performance Test

[0186] The batteries prepared in the examples and comparative examples were subjected to the following tests:

[0187] At 25 / 45℃, the lithium-ion secondary battery was first charged at a constant current of 1C to the upper limit voltage (4.35V for NCM622 and NCM811, and 4.7V for Li-rich). Then, it was charged again at the upper limit voltage to a constant current of 0.05C. Finally, the battery was discharged at a constant current of 1C to 2.8V. This constitutes one charge-discharge cycle, and the discharge capacity of this cycle is the discharge capacity of the first cycle. The battery underwent multiple charge-discharge cycles in the above manner, and the discharge capacity after the 500th cycle was measured. The capacity retention rate after the cycles was calculated using the following formula. The test results are shown in Table 3 below.

[0188] Battery capacity retention rate (%) after 500 cycles = [Discharge capacity of the 500th cycle / Discharge capacity of the 1st cycle] × 100%

[0189] (2) Battery storage performance test at 60°C

[0190] The batteries prepared in the examples and comparative examples were subjected to the following tests:

[0191] At 25℃, the battery was charged at a constant current of 1C to the upper limit voltage (4.35V for NCM622 and NCM811, and 4.7V for Li-rich). Then, the battery was charged at a constant voltage of the upper limit voltage until the current was less than 0.05C. The battery was then discharged at a constant current of 1C to 2.8V. This process was repeated: the battery was charged again at a constant current of 1C to the upper limit voltage, and then charged at a constant voltage of the upper limit voltage until the current was less than 0.05C. The battery was then stored at 60℃ for 30 days. After storage, the battery was discharged at a constant current of 1C to 2.8V. This process was repeated again: the battery was charged again at a constant current of 1C to the upper limit voltage, and then charged at a constant voltage of the upper limit voltage until the current was less than 0.05C. The battery was then discharged at a constant current of 1C to 3.0V. This process was repeated three times, and the capacity of the last discharge was taken as the recoverable capacity. The test results are shown in Table 2 below.

[0192] Battery recovery capacity percentage (%) = [Battery recovery capacity after high temperature storage / Battery capacity before storage] × 100%.

[0193] Battery performance test items are shown in Table 2.

[0194] Table 2

[0195]

[0196] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A cathode material for use in lithium-ion batteries, characterized in that, It includes an inner core and a covering layer covering the surface of the inner core; The core contains a positive electrode active material, the coating layer contains halloysite material, and a conductive polymer material is laminated on the coating layer; The halloysite material comprises 0.1% to 4% of the core by mass. The conductive polymer material accounts for 0.3% to 5% of the total mass of the core.

2. The cathode material according to claim 1, characterized in that, The halloysite material comprises 0.1% to 3% of the total mass of the core.

3. The cathode material according to claim 2, characterized in that, The halloysite material comprises 1.5% to 2% by mass.

4. The cathode material according to claim 1, characterized in that, The halloysite material comprises a tubular structure.

5. The positive electrode material according to claim 1, characterized in that, The halloysite material comprises a nanotube structure, which satisfies at least one of the following characteristics: (1) The length is ≤0.05μm; (2) The outer diameter is 30nm~70nm; (3) The inner diameter is 5nm to 20nm.

6. The cathode material according to claim 1, characterized in that, The conductive polymer material accounts for 2% to 5% of the mass of the core.

7. The positive electrode material according to claim 1, characterized in that, The conductive polymer material includes one or more of polyethylene glycol, polyethylene, polypropylene, polyacetylene, polypyrrole, polythiophene, polyaniline, and derivatives of the aforementioned materials.

8. The cathode material according to any one of claims 1 to 7, characterized in that, The positive electrode active material includes one or both of high-nickel ternary materials and lithium-rich materials.

9. The cathode material according to claim 8, characterized in that, The chemical formula of the high-nickel ternary material is LiNi. x Co y Mn 1-x-y O2, where x ≥ 0.5, 0 ≤ y ≤ 0.2; and / or, The chemical formula of the lithium-rich material is nLi2MnO3·(1-n)LiMO2, where 0≤n≤1 and M is one or more of Ni, Co and Mn.

10. A method for preparing a positive electrode material, wherein the positive electrode material is used in a lithium-ion battery, characterized in that, Includes the following steps: A first product is prepared by mixing an inner core material, a coating layer material, and a first solvent, removing the first solvent, and performing a first sintering. The inner core material contains a positive electrode active material, and the coating layer material contains halloysite material. The mass percentage of the halloysite material is 0.1% to 4% of the mass percentage of the inner core material. The first product is mixed with a second solvent and monomers of a conductive polymer material, and the monomers of the conductive polymer material are subjected to in-situ polymerization on the first product to generate a conductive polymer material. The second solvent is then removed to prepare the second product. The conductive polymer material has a mass percentage of 0.3% to 5% of the core material. The second product is sintered a second time to prepare the cathode material.

11. The method for preparing the cathode material according to claim 10, characterized in that, The process includes a short-tube treatment of the halloysite material before mixing the core material, the coating material, and the first solvent.

12. The method for preparing the cathode material according to claim 11, characterized in that, The method for shortening the tubes is ultrasonic treatment.

13. The method for preparing the cathode material according to claim 12, characterized in that, The conditions for ultrasonic treatment include: ultrasonic power of 800W to 1200W and time of 2h to 5h.

14. The method for preparing the cathode material according to claim 10, characterized in that, The conditions for the first sintering include at least one of (1) to (2): (1) The temperature of the first sintering is 500℃~800℃; (2) The first sintering time is 90 min to 360 min.

15. The method for preparing the cathode material according to claim 14, characterized in that, The first sintering temperature is 600℃~750℃; and / or, The heating rate to the first sintering temperature is 1–10 °C / min; and / or, The first sintering time is 180 min to 300 min.

16. The method for preparing the cathode material according to any one of claims 10 to 15, characterized in that, The conditions for the second sintering include at least one of (1) to (2): (1) The temperature of the second sintering is 250℃~380℃; (2) The second sintering time is 30 min to 240 min.

17. The method for preparing the cathode material according to claim 16, characterized in that, The second sintering temperature is 300℃~360℃; and / or, The heating rate to the second sintering temperature is 1–10 °C / min; and / or, The second sintering time is 60 min to 180 min.

18. The method for preparing the cathode material according to any one of claims 10 to 15, characterized in that, The conditions for in-situ polymerization include at least one of (1) to (3): (1) The temperature is 0~5℃; (2) The time is 5h to 10h; (3) The process is carried out under the induction of an inducing agent.

19. The method for preparing the cathode material according to claim 18, characterized in that, The inducing agent includes one or more of water-soluble redox agents and peroxides.

20. The method for preparing the cathode material according to claim 19, characterized in that, The inducing agent includes one or both of hydrogen peroxide and oxalic acid.

21. The method for preparing the cathode material according to any one of claims 10 to 15, characterized in that, The method for removing the first solvent or the second solvent is vacuum drying or vacuum freeze drying.

22. The method for preparing the cathode material according to claim 21, characterized in that, Vacuum drying is performed at a temperature of 100–150°C for 10–20 hours; and / or, The temperature for vacuum freeze drying is -50 to -30°C, and the time is 10 to 20 hours.

23. A positive electrode plate, characterized in that, It includes the positive electrode current collector and the positive electrode active material layer; The positive electrode active material layer is located on the surface of the positive electrode current collector, and the material of the positive electrode active material layer includes the positive electrode material as described in any one of claims 1 to 9 or the positive electrode material prepared by the preparation method described in any one of claims 10 to 22.

24. An electrode assembly, characterized in that, It includes a negative electrode sheet, a separator, and a positive electrode sheet as described in claim 23, which are stacked together.

25. A lithium-ion battery, characterized in that, It includes a housing, an electrolyte, and an electrode assembly as described in claim 24; the electrolyte and the electrode assembly are housed within the housing.

26. An electrical appliance, characterized in that, Including the lithium-ion battery as described in claim 25.

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