Positive electrode active material, positive electrode sheet, battery, management method and application

Abstract

The application provides a positive electrode active material, a positive electrode sheet, a battery, a battery management method, and a power utilization device. The positive electrode active material comprises a lithium-rich manganese-based material with a chemical formula of nLi2MnO3·(1-n)LiMO2 and a ternary material with a chemical formula of LiNi a Mn (1‑a‑b) M’ b O2, and the mass percentage of the lithium-rich manganese-based material is greater than or equal to 50% in the positive electrode active material. In the positive electrode active material, the lithium-rich manganese-based material and the ternary material with the corresponding chemical formula are matched, and the mass percentage of the lithium-rich manganese-based material in the positive electrode active material is controlled, so that the positive electrode active material can effectively balance the high gram capacity and the low capacity attenuation, and the cycle performance of the battery can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a positive electrode active material, a positive electrode sheet, a battery, a battery management method, and an electrical device. Background Technology

[0002] Ternary materials are widely used as positive electrode active materials in lithium-ion batteries due to their high specific capacity. Traditional battery research typically focuses on exploring the chemical composition of ternary materials to further improve their specific capacity. However, using ternary materials as positive electrode active materials results in rapid capacity decay, which may reduce the battery's cycle performance. Therefore, finding a positive electrode active material that balances high specific capacity with low capacity decay is crucial for further improving the overall performance of the battery. Summary of the Invention

[0003] This application provides a positive electrode active material, including a lithium-rich manganese-based material with the chemical formula nLi2MnO3·(1-n)LiMO2 and a material with the chemical formula LiNi a Mn (1-a-b) M' b The ternary material of O2, based on the mass percentage of the positive electrode active material, has the mass percentage of the lithium-rich manganese-based material ≥ 50%; wherein, 0 < n < 1, M includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Zn and Al; 0 < a < 1, 0 < b ≤ 0.5, a + b < 1, M' includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Zn and Al.

[0004] In the above-mentioned positive electrode active materials, by selecting lithium-rich manganese-based materials and ternary materials with corresponding chemical formulas and controlling the mass percentage of lithium-rich manganese-based materials in the positive electrode active materials, the positive electrode active materials can effectively balance high specific capacity and low capacity decay, thereby improving the cycle performance of the battery.

[0005] In some embodiments, the lithium-rich manganese-based material particles include lithium-rich manganese-based secondary particles. These secondary particles facilitate lithium-ion diffusion and electrochemical reactions, thereby improving the rate performance of the battery.

[0006] In some embodiments, the Dv50 of the lithium-rich manganese-based secondary particles is 6 μm to 9 μm. A Dv50 within this range can reduce the lithium-ion transport path, further improving the rate performance of the battery.

[0007] In some embodiments, the specific surface area of ​​the lithium-rich manganese-based secondary particles is 0.7 m². 2 / g~1.1m 2 / g. The specific surface area of ​​lithium-rich manganese-based secondary particles is within this range, which can provide more reactive sites and is beneficial for rate performance.

[0008] In some embodiments, the lithium-rich manganese-based secondary particles are spherical or near-spherical in shape. Spherical or near-spherical lithium-rich manganese-based secondary particles can achieve more thorough contact with the electrolyte, which is beneficial for improving battery performance.

[0009] In some embodiments, the lithium-rich manganese-based material comprises ≥60% by mass of the positive electrode active material. Optionally, the lithium-rich manganese-based material comprises ≥70% by mass. Further optionally, the lithium-rich manganese-based material comprises ≤80% by mass. Within this range, the lithium-rich manganese-based material can better balance higher specific capacity and lower capacity decay, further improving the cycle performance of the battery.

[0010] In some implementations, 0.1 ≤ n ≤ 0.3. When n is in the range of 0.1 to 0.3, the lithium-rich manganese-based material can have a larger specific capacity, allowing the positive electrode active material to better balance high specific capacity and low capacity decay.

[0011] In some embodiments, the chemical formula of the lithium-rich manganese-based material is nLi₂MnO₃·(1-n)LiNi x Mn (1-x-y) M” y O2, wherein 0 < x < 1, 0 < y ≤ 0.5, x + y < 1, and M" includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Zn, and Al. This type of lithium-rich manganese-based material has superior performance advantages and can better improve the cycle performance of batteries.

[0012] In some implementations, 0 < y ≤ 0.1. When y is within this range, M” has a suitable content, which can improve the performance of lithium-rich manganese-based materials while maintaining the specific capacity of lithium-rich manganese-based materials, and is beneficial to improving the cycle performance of cathode materials and batteries.

[0013] In some embodiments, "M" includes Co. By doping lithium-rich manganese-based materials with Co, the intrinsic properties of lithium-rich manganese-based materials can be better maintained, while enabling the positive electrode active material to effectively balance high specific capacity and low capacity decay.

[0014] In some embodiments, the ternary material comprises ≤50% of the positive electrode active material by mass. An excessively high ternary material mass percentage may result in significant capacity decay of the positive electrode active material, which is detrimental to capacity retention.

[0015] In some embodiments, the ternary material comprises 20% to 40% by mass. A low mass percentage of ternary material may result in a low energy density of the positive electrode active material, which is detrimental to the design of high-energy-density batteries.

[0016] In some embodiments, the ternary material particles comprise ternary secondary particles. Ternary secondary particles facilitate lithium-ion diffusion and electrochemical reactions, thereby improving the rate performance of the battery.

[0017] In some embodiments, the Dv50 of the ternary secondary particles is 5 μm to 7 μm. The particle size of the ternary secondary particles within this range can reduce the lithium-ion transport path, further improving the rate performance of the battery.

[0018] In some embodiments, the specific surface area of ​​the ternary secondary particles is 0.6 m². 2 / g~0.8m 2 / g. The specific surface area of ​​ternary secondary particles within this range can provide more reactive sites, which is beneficial for rate performance.

[0019] In some embodiments, the ternary secondary particles are spherical or near-spherical in shape. Spherical or near-spherical ternary secondary particles can make more thorough contact with the electrolyte, which is beneficial for improving battery performance.

[0020] This application also provides a positive electrode sheet, comprising a positive current collector and a positive electrode film layer located on at least one surface of the positive current collector, the positive electrode film layer comprising the positive electrode active material. Applying the above-mentioned positive electrode active material to the positive electrode sheet can effectively balance high specific capacity and low capacity decay, thereby improving the cycle performance of the battery.

[0021] This application also provides a battery including the aforementioned positive electrode. This battery exhibits good cycle capacity retention performance.

[0022] This application also provides a method for managing the battery, comprising the following steps: charging the battery with a voltage ≤4.4V. Within this voltage range, the battery can exhibit higher initial coulombic efficiency, lower capacity decay, and better safety performance.

[0023] In some embodiments, the voltage is 4.35V to 4.4V. A charging voltage within this range allows the battery to maintain good performance while increasing its charging speed.

[0024] This application also provides an electrical device including the battery. The introduction of the battery enables the electrical device to possess good electrical performance. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a battery according to one embodiment of this application.

[0026] Figure 2 yes Figure 1 An exploded view of a battery according to one embodiment of this application is shown.

[0027] Figure 3 This is a schematic diagram of a battery module according to one embodiment of this application.

[0028] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0029] Figure 5 yes Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown.

[0030] Figure 6 This is a schematic diagram of an electrical device in which a battery is used as a power source according to one embodiment of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Battery pack; 2. Upper housing; 3. Lower housing; 4. Battery module; 5. Battery; 51. Housing; 52. Electrode assembly; 53. Top cover assembly. Detailed Implementation

[0033] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the battery assembly, battery cell, battery, and power-consuming device of this application. 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 this application and are not intended to limit the subject matter of the claims.

[0034] The "range" disclosed in this application is defined by 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 a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. 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 application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" 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.

[0035] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0036] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0037] Unless otherwise specified, all steps in this application 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.

[0038] Unless otherwise specified, the terms "comprising" and "including" as used in this application 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.

[0039] Unless otherwise specified, the term "or" is inclusive in this application. 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 both A and B exist.

[0040] Unless otherwise specified, in this application, the terms "positive electrode sheet" and "positive electrode plate" have the same meaning and can be used interchangeably. The terms "negative electrode sheet" and "negative electrode plate" have the same meaning and can be used interchangeably. The terms "diaphragm" and "separating membrane" have the same meaning and can be used interchangeably.

[0041] One embodiment of this application provides a positive electrode active material. This positive electrode active material includes a lithium-rich manganese-based material with the chemical formula nLi₂MnO₃·(1-n)LiMO₂ and a material with the chemical formula LiNi. a Mn (1-a-b) M' b The ternary material of O2, based on the mass percentage of the positive electrode active material, has a lithium-rich manganese-based material mass percentage ≥ 50%; wherein, 0 < n < 1, M includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Zn, and Al; 0 < a < 1, 0 < b ≤ 0.5, a + b < 1, M' includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Zn, and Al. In the positive electrode active material of this embodiment, by selecting the appropriate chemical formulas for the ratio of lithium-rich manganese-based material and ternary material, and controlling the mass percentage of lithium-rich manganese-based material in the positive electrode active material, the positive electrode active material can effectively balance high specific capacity and low capacity decay, thereby improving the cycle performance of the battery. Meanwhile, in the positive electrode active material of this embodiment, by adjusting the ratio of lithium-rich manganese-based material and ternary material, the positive electrode active material can have better rate performance.

[0042] Optionally, n can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc. Optionally, a can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc. Optionally, b can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc. Optionally, b ≤ 0.1. Optionally, a + b ≤ 0.98, or a + b ≤ 0.95, or a + b ≤ 0.9, or a + b ≤ 0.88, or a + b ≤ 0.85, or a + b ≤ 0.8, or a + b ≤ 0.78, or a + b ≤ 0.75, or a + b ≤ 0.7, etc. Understandably, n can also be chosen within the range of 0 < n < 1. a, b, and a+b can also be selected within the ranges of 0 < a < 1, 0 < b ≤ 0.5, and a+b < 1, respectively.

[0043] In some embodiments, the lithium-rich manganese-based material particles include lithium-rich manganese-based secondary particles. These secondary particles facilitate lithium-ion diffusion and electrochemical reactions, thereby improving the rate performance of the battery.

[0044] Optionally, the Dv50 of lithium-rich manganese-based secondary particles is 6μm to 9μm. For example, the Dv50 of lithium-rich manganese-based secondary particles can be 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, etc. Within this particle size range, the lithium-ion transport path can be narrowed, further improving the rate performance of the battery.

[0045] It is understood that in this application, Dv50 refers to the particle size corresponding to the cumulative particle size distribution number reaching 50% in the volume cumulative distribution curve. Physically, it means that 50% of the particles are smaller (or larger) than Dv50. As an example, Dv50 can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, according to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method.

[0046] Optionally, the specific surface area of ​​the lithium-rich manganese-based secondary particles is 0.7 m². 2 / g~1.1m 2 / g. For example, the specific surface area of ​​lithium-rich manganese-based secondary particles is 0.7m². 2 / g, 0.8m 2 / g, 0.9m 2 / g、1m 2 / g, 1.1m 2 / g etc. The specific surface area of ​​lithium-rich manganese-based secondary particles is within this range, which can provide more reactive sites and is beneficial to rate performance.

[0047] Optionally, the lithium-rich manganese-based secondary particles have a spherical or near-spherical morphology. Spherical or near-spherical lithium-rich manganese-based secondary particles can make more thorough contact with the electrolyte, which is beneficial for improving battery performance.

[0048] It is understood that the specific surface area test method in this application can be obtained by conventional gas adsorption method.

[0049] In some embodiments, the structure of the lithium-rich manganese-based secondary particles includes aggregated lithium-rich manganese-based primary particles. Optionally, the morphology of the lithium-rich manganese-based primary particles is spherical or near-spherical. Spherical or near-spherical lithium-rich manganese-based primary particles can have more sufficient contact with the electrolyte, which is beneficial for improving battery performance.

[0050] In some embodiments, the mass percentage of lithium-rich manganese-based material is ≥60% based on the mass percentage of the positive electrode active material. Optionally, the mass percentage of lithium-rich manganese-based material is ≥65% based on the mass percentage of the positive electrode active material. Further optionally, the mass percentage of lithium-rich manganese-based material is ≥70% based on the mass percentage of the positive electrode active material. Using lithium-rich manganese-based material as the main material in the positive electrode active material is beneficial for improving the cycle performance of the battery. Further optionally, the mass percentage of lithium-rich manganese-based material is ≤80%. Within the above range, the mass percentage of lithium-rich manganese-based material can better balance higher specific capacity and lower capacity decay, further improving the cycle performance of the battery.

[0051] In some embodiments, in lithium-rich manganese-based materials with the chemical formula nLi₂MnO₃·(1-n)LiMO₂, 0.1 ≤ n ≤ 0.3. When n is in the range of 0.1 to 0.3, the lithium-rich manganese-based material can have a larger specific capacity, allowing the positive electrode active material to better balance high specific capacity and low capacity decay. Optionally, at a charging cutoff voltage of ≤4.4V, the specific capacity of the lithium-rich manganese-based material is ≥150mAh / g. Optionally, the specific capacity testing conditions are: voltage 2.5–4.35V, current 0.33C, charging using CC-CV method, cutoff current 0.05C, and discharging using 0.33C constant current discharge. At a charging cutoff voltage of ≤4.4V, the specific capacity advantage of the lithium-rich manganese-based material can be better demonstrated.

[0052] In some embodiments, the chemical formula of the lithium-rich manganese-based material is nLi₂MnO₃·(1-n)LiNi x Mn (1-x-y) M” y O2, wherein 0 < x < 1, 0 < y ≤ 0.5, x + y < 1, and M" includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Zn, and Al. This type of lithium-rich manganese-based material has superior performance advantages and can better improve the cycle performance of batteries.

[0053] Optionally, x can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc. Optionally, y can be 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc.

[0054] Further optionally, 0 < y ≤ 0.1. When y is within this range, M” has a suitable content, which can improve the performance of lithium-rich manganese-based materials while maintaining the specific capacity of lithium-rich manganese-based materials, and is beneficial to improving the cycle performance of cathode materials and batteries.

[0055] Optionally, "M" includes Co. By doping lithium-rich manganese-based materials with Co, the intrinsic properties of lithium-rich manganese-based materials can be better maintained, while enabling the positive electrode active material to effectively balance high specific capacity and low capacity decay.

[0056] In some implementations, the ternary material's mass percentage is ≤50% of the positive electrode active material. An excessively high mass percentage of the ternary material may lead to significant capacity decay in the positive electrode active material, which is detrimental to capacity retention.

[0057] Optionally, the ternary material comprises 20% to 40% by mass. A too small mass percentage of ternary material may result in a lower energy density of the positive electrode active material, which is detrimental to the design of high-energy-density batteries. Further, optionally, the mass percentage of ternary material as a percentage of the positive electrode active material is 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.

[0058] As examples of ternary material particle structures, ternary materials include ternary secondary particles. Ternary secondary particles facilitate lithium-ion diffusion and electrochemical reactions, thus improving battery rate performance.

[0059] Optionally, the Dv50 of the ternary secondary particles is 5μm to 7μm. For example, the Dv50 of the ternary secondary particles is 5μm, 5.5μm, 6μm, 6.5μm, 7μm, etc. Within this particle size range, the transport path of lithium ions can be narrowed, further improving the rate performance of the battery.

[0060] Optionally, the specific surface area of ​​the ternary secondary particles is 0.6 m². 2 / g~0.8m 2 / g. Optionally, the specific surface area of ​​the ternary secondary material is 0.6m². 2 / g, 0.65m 2 / g, 0.7m 2 / g, 0.75m 2 / g, 0.8m 2 / g etc. The specific surface area of ​​ternary secondary particles within this range can provide more reactive sites, which is beneficial for rate performance.

[0061] Optionally, the ternary secondary particles have a spherical or near-spherical morphology. Spherical or near-spherical ternary secondary particles can make more thorough contact with the electrolyte, which is beneficial for improving battery performance.

[0062] Furthermore, the structure of the ternary secondary particles includes aggregated ternary primary particles. Optionally, the morphology of the ternary primary particles is spherical or near-spherical. Spherical or near-spherical ternary primary particles can have more sufficient contact with the electrolyte, which is beneficial for improving battery performance.

[0063] In some implementations, LiNi is used as a ternary material a Mn (1-a-b) M' b Example of M' selection in O2, where M' includes Co.

[0064] In some embodiments, the positive electrode active material is composed of a lithium-rich manganese-based material and a ternary material. That is, the positive electrode active material is composed of a lithium-rich manganese-based material with the chemical formula nLi₂MnO₃·(1-n)LiMO₂ and a ternary material with the chemical formula LiNi. a Mn (1-a-b) M' b The ternary material composition of O2, based on the mass percentage of the positive electrode active material, includes lithium-rich manganese-based material with a mass percentage ≥ 50%; wherein, 0 < n < 1, M includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Zn and Al; 0 < a < 1, 0 < b ≤ 0.1, a + b < 1, M' includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Zn and Al.

[0065] Another embodiment of this application provides a method for preparing the above-mentioned positive electrode active material. The method includes the following steps: mixing a lithium-rich manganese-based material and a ternary material. Optionally, the mixing method is dry mixing. It is understood that when mixing the lithium-rich manganese-based material and the ternary material, the mixing uniformity of the lithium-rich manganese-based material and the ternary material can be improved by controlling the mixing time and mixing speed.

[0066] Another embodiment of this application provides a positive electrode sheet. The positive electrode sheet includes a positive current collector and a positive electrode film layer located on at least one surface of the positive current collector, the positive electrode film layer comprising the aforementioned positive electrode active material. Applying the aforementioned positive electrode active material to the positive electrode sheet allows the positive electrode sheet to effectively balance high specific capacity and low capacity decay, thereby improving the cycle performance of the battery.

[0067] Optionally, the positive electrode active material accounts for ≥95% of the mass percentage of the positive electrode film. Within this range, the mass percentage of the positive electrode active material allows the electrode to have a higher energy density, which is beneficial for providing a higher energy density for the battery.

[0068] Further, optionally, the positive electrode film layer may also include one or more of a binder and a conductive agent.

[0069] Another embodiment of this application provides a battery. This battery includes the aforementioned positive electrode. This battery exhibits good cycle capacity retention performance.

[0070] It is understood that the battery in this application may be a rechargeable battery.

[0071] Another embodiment of this application provides a method for managing the above-mentioned battery. The method includes the following steps: charging the battery with a voltage ≤4.4V. Within this voltage range, the battery can exhibit higher initial coulombic efficiency, lower capacity decay, and better safety performance.

[0072] Optionally, the voltage is ≤4.35V. More preferably, the voltage is 4.35V to 4.4V. For example, the voltage can be 4.35V, 4.36V, 4.37V, 4.38V, 4.39V, 4.4V, etc. A charging voltage within this range allows the battery to maintain good performance while increasing its charging speed.

[0073] It is understandable that battery management includes formation and charging during operation. When management is focused on formation, the battery is the product after assembly but before formation. When management is focused on charging during operation, the battery is the product after formation.

[0074] This application also provides a battery module. The battery module includes the battery described above.

[0075] This application also provides a battery pack. The battery pack includes the battery or the battery module described above.

[0076] This application also provides an electrical device. The electrical device includes at least one of the above-described battery, battery module, and battery pack.

[0077] The battery will be explained below with reference to the accompanying drawings.

[0078] Typically, a battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and releasing. The electrolyte acts as a conductor between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ions to pass through.

[0079] [Positive electrode plate]

[0080] The positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector.

[0081] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector. Optionally, the positive current collector is the current collector described above.

[0082] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may 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 may be formed by forming a metal material on the polymer substrate. Optionally, the metal material may include, but is not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Optionally, the polymer substrate may include, but is not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0083] In some embodiments, when the battery is a lithium-ion battery, the positive electrode active material may be a positive electrode active material known in the art for lithium-ion batteries. Optionally, the positive electrode active material includes the above-mentioned positive electrode active materials. Further, as an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds. Optionally, lithium cobalt oxide includes LiCoO2. Lithium nickel oxide includes LiNiO2. Lithium manganese oxide includes at least one of LiMnO2 and LiMn2O4. Lithium nickel cobalt manganese oxide includes LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM 523 LiNi 0.5 Co 0.25 Mn 0.25 O2(NCM 211 LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM 622 ) and LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM 811 At least one of the following. Lithium nickel cobalt aluminum oxides include LiNi 0.85 Co 0.15 Al 0.05 O2. Examples of lithium phosphates with an olivine structure may include, but are not limited to, at least one of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Optionally, lithium iron phosphate includes LiFePO4 (LFP). Lithium manganese phosphate includes LiMnPO4.

[0084] In some embodiments, when the battery is a sodium-ion battery, the positive electrode active material can be any positive electrode active material known in the art for use in sodium-ion batteries. As an example, the positive electrode active material can be a single material or a combination of two or more. The positive electrode active material can be selected from sodium-iron composite oxides, sodium-cobalt composite oxides, sodium-chromium composite oxides, sodium-manganese composite oxides, sodium-nickel composite oxides, sodium-nickel-titanium composite oxides, sodium-nickel-manganese composite oxides, sodium-iron-manganese composite oxides, sodium-nickel-cobalt-manganese composite oxides, sodium-iron phosphate compounds, sodium-manganese phosphate compounds, sodium-cobalt phosphate compounds, Prussian blue-based materials, polyanionic materials, etc., but this application is not limited to these materials. Other conventionally known materials that can be used as positive electrode active materials for sodium-ion batteries can also be used. Optionally, the sodium-iron composite oxide includes NaFeO2. The sodium-cobalt composite oxide includes NaCoO2. The sodium-chromium composite oxide includes NaCrO2. The sodium-manganese composite oxide includes NaMnO2. The sodium-nickel composite oxide includes NaNiO2. The sodium-nickel-titanium composite oxide includes NaNi 1 / 2 Ti 1 / 2 O2. Sodium-nickel-manganese composite oxides include NaNi 1 / 2 Mn 1 / 2 O2. Sodium-iron-manganese composite oxides include Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2. Sodium-nickel-cobalt-manganese composite oxides include NaNi 1 / 3Co 1 / 3 Mn 1 / 3 O2. Sodium iron phosphate compounds include NaFePO4. Sodium manganese phosphate compounds include NaMnPO4. Sodium cobalt phosphate compounds include NaCoPO4. Polyanionic materials include at least one of phosphates, fluorophosphates, pyrophosphates, and sulfates.

[0085] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0086] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0087] In some embodiments, the positive electrode sheet can be prepared by dispersing the components used to prepare the positive electrode sheet, such as the positive electrode active material, conductive agent, binder, and any other components, in a solvent to form a positive electrode slurry; coating the positive electrode slurry onto a positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing, and other processes. Optionally, the solvent includes N-methylpyrrolidone (NMP).

[0088] [Negative electrode plate]

[0089] The negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer including a negative electrode active material.

[0090] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector. Optionally, the positive electrode current collector is the above-described current collector.

[0091] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. 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 may be formed by forming a metal material on the polymer material substrate. Optionally, the metal material includes at least one of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. The polymer material includes at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0092] In some embodiments, 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. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application 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.

[0093] In some embodiments, the negative electrode film 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), carboxymethyl chitosan (CMCS), polyamide-imide (PAI), polyethyleneimine (PEI), polyimide (PI), and tert-butyl polyacrylate-triethoxyvinylsilane (TBATEVS).

[0094] In some embodiments, the negative electrode film 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.

[0095] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners. Optionally, the thickener includes sodium carboxymethyl cellulose (CMC-Na).

[0096] In some embodiments, 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 to form a negative electrode slurry; coating the negative electrode slurry onto a negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing, and other processes. Optionally, the solvent includes deionized water.

[0097] Electrolyte

[0098] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements.

[0099] In some embodiments, the electrolyte comprises an electrolyte salt and a solvent.

[0100] In some embodiments, 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.

[0101] In some embodiments, 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.

[0102] In some embodiments, 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.

[0103] [Isolation membrane]

[0104] In some embodiments, the battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0105] In some embodiments, 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.

[0106] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0107] In some embodiments, the battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.

[0108] In some implementations, the battery's outer packaging can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The battery's outer packaging can also be a soft pack, such as a pouch. The soft pack can be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0109] This application does not impose any particular limitation on the shape of the battery; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 1 The battery 5 is a square structure, which serves as an example.

[0110] In some implementations, refer to Figure 2 The outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be placed over the opening to close the receiving cavity. A positive electrode, a negative electrode, and a separator can be formed into an electrode assembly 52 using a winding or stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The 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.

[0111] In some implementations, the batteries can be assembled into battery modules, and the number of 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.

[0112] Figure 3 This is battery module 4, used as an example. (See reference...) Figure 3 In battery module 4, multiple 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, these multiple batteries 5 can be fixed in place using fasteners.

[0113] Optionally, the battery module 4 may also include a housing with a receiving space in which a plurality of batteries 5 are received.

[0114] 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.

[0115] 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.

[0116] In addition, this application also provides an electrical device, which includes at least one of the battery, battery module, or battery pack provided in this application. The battery, battery module, or battery pack can be used as a power source for the electrical device or as an energy storage unit for 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. For example, mobile devices include mobile phones, laptops, etc. Electric vehicles include pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.

[0117] As the electrical device, a battery, battery module, or battery pack can be selected according to its usage requirements.

[0118] Figure 6This is an example of an electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the device's requirements for high power and high energy density, a battery pack or battery module can be used.

[0119] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can be powered by a battery.

[0120] Example

[0121] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0122] (1) Examples 1 to 25

[0123] The positive electrode active materials in Examples 1 to 25 include lithium-rich manganese-based materials and ternary materials. The chemical formula, mass percentage, secondary particle size and specific surface area, and primary particle size and specific surface area of ​​the lithium-rich manganese-based materials and ternary materials are shown in Table 1.

[0124] Example 26

[0125] The difference between Example 2 and Example 26 is that the lithium-rich manganese-based material has a Dv50 of 3 μm and a specific surface area of ​​0.6 m². 2 / g of single-stage particles.

[0126] Example 27

[0127] The difference between Example 2 and Example 27 is that the ternary material has a Dv50 of 3 μm and a specific surface area of ​​0.6 m². 2 / g of single-stage particles.

[0128] Example 28

[0129] The difference between Example 2 and Example 28 is that the lithium-rich manganese-based material has a Dv50 of 3 μm and a specific surface area of ​​0.6 m². 2 / g of primary particles. The ternary material has a Dv50 of 3μm and a specific surface area of ​​0.6m². 2 / g of single-stage particles.

[0130] Comparative Examples 1 to 2

[0131] Compared with Example 2, the difference between Comparative Examples 1 and 2 is that the mass percentages of the lithium-rich manganese-based material and the ternary material are different.

[0132] In Examples 1 to 28 and Comparative Examples 1 to 2, the lithium-rich manganese-based secondary particles were spherical, and the lithium-rich manganese-based primary particles were spherical or near-spherical. The ternary secondary particles were spherical, and the ternary primary particles were spherical or near-spherical.

[0133] (2) Battery preparation.

[0134] ① Preparation of the positive electrode sheet.

[0135] The lithium-rich manganese-based material and ternary material corresponding to the examples and comparative examples were mixed evenly to obtain the positive electrode active material of the corresponding examples and comparative examples.

[0136] The positive electrode active material, PVDF binder, SP conductive agent, and NMP solvent were stirred and mixed for 1.5 h to obtain the positive electrode slurry. The mass ratio of the positive electrode active material, PVDF binder, and SP conductive agent was 95:2.5:2.5.

[0137] The positive electrode slurry is coated onto aluminum foil and dried to obtain the positive electrode sheet. The areal density of the positive electrode film layer in the positive electrode sheet is 0.2 g / cm³. 2 .

[0138] ② Preparation of negative electrode sheet.

[0139] A negative electrode slurry was prepared by mixing graphite (anode active material), CMC (binder), SBR (semiconductor polymer), and SP (conductive agent) with deionized water at a mass ratio of 93:2:2:3 for 2 hours. The negative electrode active material had a mass fraction greater than 96%. The negative electrode slurry was then coated onto copper foil and dried to obtain a negative electrode sheet. The areal density of the negative electrode film layer in the negative electrode sheet was 0.1 g / cm³. 2 .

[0140] ③ Electrolyte.

[0141] In the electrolyte, the lithium salt is 1M LiPF6, and the solvent is a mixture of EC and EMC with a volume ratio of 1:1.

[0142] ④ The separator is a PP film.

[0143] (3) Test Case

[0144] ① Specific capacity of the positive electrode active material: The positive electrode sheet was cut into small circular pieces with a diameter of 20 mm and assembled with lithium metal sheets into coin cells. The specific capacity was tested under conditions of 0.33C and 2.5–4.4V. The results are shown in Table 1, with units of mAh / g. ② Battery cycle retention: The prepared positive and negative electrode sheets were assembled into a pouch cell. The battery was charged using the CC-CV method with a constant voltage charging cutoff current of 0.05C, discharged using the CC method with a constant current charge-discharge rate of 0.33C and a voltage range of 2.5–4.35V. The battery cycle performance is expressed as the capacity retention rate after 1000 cycles. The results are shown in Table 1, with units of %.

[0145] ③ Rate performance: The prepared positive and negative electrode sheets were assembled into a pouch cell, and charge-discharge tests were conducted within the 2.5–4.35V range. Charging was performed using the CC-CV method, with a cutoff current of 0.05C and discharge currents of 0.33C and 2C. The ratio of the capacity obtained at 2C discharge to the capacity obtained at 0.33C discharge reflects the battery's rate performance. The results are shown in Table 1.

[0146] (4) Examples 29 to 30

[0147] The difference between Example 2 and Example 29 is that the charging voltage during the test was 4.5V.

[0148] The difference between Example 2 and Example 30 is that the charging voltage during the test is 4.8V.

[0149] In Table 1, the mass percentage represents the mass percentage of lithium-rich manganese-based materials or ternary materials in the positive electrode active material.

[0150] Table 1

[0151]

[0152]

[0153] As can be seen from Table 1, when the mass percentage of lithium-rich manganese-based materials in the positive electrode active material is ≥50%, it can better balance higher specific capacity and lower capacity decay, thus giving the battery better cycle performance and rate performance.

[0154] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. 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 this application, are also included in the scope of this application.

Claims

1. A positive electrode active material, characterized by, a lithium-rich manganese-based material having a chemical formula of nLi2Mn03·(1-n)LiM02 and a ternary material having a chemical formula of LiNi a Mn (1-a-b) M’ b O2, a mass percentage of the lithium-rich manganese-based material is ≥ 50% based on a mass percentage of the positive electrode active material; particles of the ternary material include ternary secondary particles; wherein 0 < n < 1, M comprises one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Zn and Al; 0 < a < 1, 0 < b ≤ 0.5, a + b < 1, M' comprises one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Zn and Al.

2. The positive electrode active material according to claim 1, characterized by The particles of the lithium-rich manganese-based material comprise lithium-rich manganese-based secondary particles.

3. The positive electrode active material according to claim 2, characterized by The Dv50 of the lithium-rich manganese-based secondary particles is 6 μm to 9 μm.

4. The positive electrode active material according to claim 2, characterized by The lithium-rich manganese-based secondary particles have a specific surface area of 0.7 m 2 / g ~ 1.1 m 2 / g.

5. The positive electrode active material according to claim 2, characterized by The morphology of the lithium-rich manganese-based secondary particles is spherical or quasi-spherical.

6. The positive electrode active material according to any one of claims 1 to 5, characterized by The mass percentage of the lithium-rich manganese-based material is ≥ 60% based on the mass percentage of the positive electrode active material.

7. The positive electrode active material according to claim 6, characterized by The mass percentage of the lithium-rich manganese-based material is ≥ 70%.

8. The positive electrode active material according to any one of claims 1 to 7, characterized by The mass percentage of the lithium-rich manganese-based material is ≤ 80%.

9. The positive electrode active material according to any one of claims 1 to 8, characterized by 0.1≤n≤0.3。 10. The positive electrode active material according to any one of claims 1 to 9, characterized by The lithium-rich manganese-based material has a chemical formula of nLi2MnO3·(1-n)LiNi x Mn (1-x-y) M'' y O2, wherein 0 x+y<1, M" includes one or more of Na, Mg, Ca, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Zn, and Al.

11. The positive electrode active material according to claim 10, characterized by 0＜y≤0.1。 12. The positive electrode active material according to claim 10, characterized by M'' comprises Co.

13. The positive electrode active material according to any one of claims 1 to 12, characterized by The mass percentage of the ternary material is ≤ 50% based on the mass percentage of the positive electrode active material.

14. The positive electrode active material according to any one of claims 1 to 13, characterized by The mass percentage of the ternary material is 20% to 40%.

15. The positive electrode active material according to any one of claims 1 to 14, characterized by The Dv50 of the ternary secondary particles is 5 μm to 7 μm.

16. The positive electrode active material according to any one of claims 1 to 15, characterized by The specific surface area of the ternary secondary particles is 0.6 m 2 / g ~ 0.8 m 2 / g.

17. The positive electrode active material according to any one of claims 1 to 16, characterized by, The morphology of the ternary secondary particles is spherical or quasi-spherical.

18. A positive electrode sheet characterized by comprising: The positive electrode film layer comprises the positive electrode active material according to any one of claims 1 to 17.

19. A battery, characterized by The positive electrode sheet according to claim 18.

20. A method of managing the battery of claim 19, wherein, The method comprises the following steps: The battery is charged using a voltage of ≤ 4.4 V.

21. The battery management method according to claim 20, wherein The voltage is 4.35 V to 4.4 V.

22. An electrical device, comprising: The battery according to claim 19.

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