Active material of a positive electrode, positive electrode plate, secondary battery and electrical device

Abstract

Active material of a positive electrode, characterized in that the active material of a positive electrode is in the form of secondary particles formed by the aggregation of primary particles, and that at least some of the secondary particles have pores; and The particle size distribution of the active material of a positive electrode, determined by laser diffraction, is bimodal and the difference between the position of the second peak and the position of the first peak is 1 µm to 13 µm.

Description

CROSS-REFERENCES

[0001] The present application incorporates Chinese patent application No. 202310473126.X dated April 27, 2023, entitled “Active material of a positive electrode, positive electrode plate, secondary battery and electrical device”, which is hereby incorporated in its entirety by reference. AREA OF INVENTION

[0002] This application relates to the field of secondary battery technology and in particular to an active material for a positive electrode, a positive electrode plate, a secondary battery and an electrical device. STATE OF THE ART

[0003] In recent years, secondary batteries have been widely used in energy storage systems such as hydroelectric, thermal, wind and solar power plants, as well as in numerous fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment and aerospace.

[0004] The performance of the active material in a positive electrode directly influences the performance of the secondary battery. Currently, active materials for positive electrodes exhibit numerous shortcomings and cannot meet the application requirements of the next generation of electrochemical systems. REVELATION OF THE INVENTION

[0005] The present application is made in view of the aforementioned problems and aims to provide an active material for a positive electrode in which at least some of the secondary particles have pores and the particle size distribution of the active material for a positive electrode is bimodal, thereby taking into account both the performance and the mechanical strength of the battery.

[0006] A first aspect of the present application relates to an active material of a positive electrode, wherein the active material of a positive electrode is in the form of secondary particles formed by aggregation of primary particles, and wherein at least some of the secondary particles have pores; and wherein the particle size distribution of the active material of a positive electrode, determined by laser diffraction, is bimodal and the difference between the second and the first peak is in the range of 1 µm to 13 µm.

[0007] On the one hand, the presence of pores is advantageous because the active material of a positive electrode has three-dimensional channels, which shortens the solid-state diffusion path of the lithium ions and improves the performance and energy density of the battery.On the other hand, the particle size distribution of the active material of a positive electrode is bimodal, which means that the combination of active materials for the positive electrode with different particle sizes not only contributes to improving the bulk density of the active material of a positive electrode, but above all, that the active materials for the positive electrode with different particle sizes can play a certain supporting role, which helps to improve the mechanical strength, reduce the risk of breakage of the active material of a positive electrode during use, improve the shear strength of the positive electrode plate and improve the mechanical strength of the battery.Furthermore, it is advantageous to limit the difference between the position of the first peak and the position of the second peak in the particle size distribution of the active material of the positive electrode to 1 µm to 13 µm in order to further improve the compaction density of the positive electrode plate and the electrical performance of the battery.

[0008] In each embodiment, the position of the first peak is between 1 µm and 5 µm, optionally between 1.5 µm and 4.5 µm; and / or

[0009] The position of the second peak is between 6 µm and 14 µm, optionally between 8 µm and 12 µm.

[0010] By controlling the positions of the first and second peaks within a suitable range, the battery exhibits a high volumetric energy density as well as excellent performance and mechanical strength.

[0011] In each embodiment, the secondary particles comprise a plurality of pores formed by the spaces between the primary particles, the inner diameter of which is 0.1 µm to 0.6 µm, optionally 0.2 µm to 0.4 µm; or the secondary particles have a single hollow pore in a central position enclosed by primary particles, the inner diameter of which is 0.5 µm to 3 µm, optionally 0.8 µm to 1.2 µm.

[0012] Pores with different distribution patterns have different internal diameters, which promotes the formation of three-dimensional channels in the active material of a positive electrode, shortens the solid-state diffusion path of the lithium ions, and improves the battery's performance.

[0013] In each embodiment, the active material of a positive electrode has the following chemical formula: Li a Ni x M1 y M2 1-x-y O2,

[0014] M1 and M2 comprise one or more of the elements Co, Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg and Nb with 0.8≤a≤1.2, 0.55≤x≤1.0 and 0≤y≤0.45 and optionally 0.8≤a≤1.2, 0.95≤x≤0.995 and 0≤y≤0.05.

[0015] The use of the aforementioned materials ensures that the active material of a positive electrode has a high specific capacity, resulting in a battery with high energy density.

[0016] In each embodiment, the mean particle size D of the primary particles of the active material of a positive electrode is 0.1 µm to 0.8 µm and can optionally be 0.2 µm to 0.5 µm.

[0017] By controlling the average particle size of the primary particles of the active material of a positive electrode within a suitable range, secondary particles of the active material of a positive electrode with a suitable range can be formed, giving the battery a high volumetric energy density, excellent performance and high mechanical strength.

[0018] In each embodiment, the Dv50 of the secondary particles of the active material of a positive electrode is 9 µm to 15 µm and can optionally be set to 10 µm to 12 µm.

[0019] Controlling the active material of a positive electrode within a suitable area gives the battery a high volumetric energy density, excellent performance, and mechanical strength.

[0020] In each embodiment, the specific surface area of ​​the active material of the positive electrode is 0.1 m². 2 / g up to 1.0 m 2 / g, optional 0.2 m 2 / g up to 0.5 m 2 / G.

[0021] By controlling the specific surface area of ​​the active material of a positive electrode within a suitable range, the battery can achieve high volumetric energy density, excellent performance, and high mechanical strength.

[0022] In each embodiment, the active material of a positive electrode comprises a first cathode material and a second cathode material.

[0023] The combination of the first and second cathode materials has a synergistic effect that helps to improve the compaction density of the positive electrode plate and increase the mechanical performance and cycle stability of the battery.

[0024] In each embodiment, the first cathode material has pores, and the second cathode material has a solid structure; or

[0025] The first cathode material is solid, the second cathode material has pores; or both the first and second cathode materials have pores.

[0026] The presence of pores can shorten the diffusion path of lithium ions in the solid phase, improve the battery's performance, and expose more (010) crystal planes, thereby creating more reactive sites and improving the material's specific capacity and energy density.

[0027] In each embodiment, the mass ratio A of the first cathode material to the second cathode material satisfies the following relationship to the porosity B of the active material of the positive electrode: 0≤|BA×0.4-(1-A)×0.2|≤1.

[0028] The targeted adjustment of the mass ratio of the first and second cathode materials, in order to ensure the aforementioned relationship to the porosity of the active material of a positive electrode, makes it possible to provide sufficient pores to shorten the solid-state diffusion path of the lithium ions and improve the performance of the battery, while at the same time the interaction force between the first and second cathode materials can be adjusted to optimize the mechanical properties of the battery.

[0029] In each embodiment, the mass ratio A of the first cathode material to the second cathode material is 1.5 to 9, optionally 2 to 8.

[0030] The mass ratio of the first cathode material to the second cathode material is controlled within a suitable range, taking into account both the compaction density of the positive electrode plate and the mechanical strength of the battery.

[0031] In each embodiment, the porosity B of the active material of a positive electrode is 0.15% to 0.45%, optionally 0.25% to 0.35%.

[0032] By controlling the porosity of the active material of a positive electrode in a suitable range, sufficient pores can be provided to shorten the solid-state diffusion path of the lithium ions and improve the performance of the battery, while avoiding or reducing the influence of the pores on the mechanical strength of the active material of a positive electrode.

[0033] In each embodiment, the first cathode material and the second cathode material each have the following chemical formula independently of each other: Li a Ni x M1 y M2 1-x-y O2,

[0034] M1 and M2 comprise one or more of the elements Co, Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg and Nb with 0.8≤a≤1.2, 0.55≤x≤1.0 and 0≤y≤0.45 and optionally 0.8≤a≤1.2, 0.95≤x≤0.995 and 0≤y≤0.05.

[0035] Both the first and second cathode materials with the aforementioned chemical formulas ensure that the active material of a positive electrode has a high specific capacity, resulting in a battery with high energy density.

[0036] In each embodiment, the Dv50 of the first cathode material is 8 µm to 18 µm, optionally 10 µm to 12 µm.

[0037] In each embodiment, the Dv50 of the second cathode material is 0.8 µm to 5 µm, optionally 1 µm to 3 µm.

[0038] Controlling the Dv50 value of the first cathode material and the Dv50 value of the second cathode material within a suitable range is advantageous for the synergy effect between the first cathode material and the second cathode material and contributes to improving the volumetric energy density and the mechanical properties of the battery.

[0039] In each embodiment, the ratio of the difference between Dv90 and Dv50 of the first cathode material to Dv50 of the first cathode material is in the range of 0.6 to 1.2, optionally 0.8 to 1.0; and / or The ratio of the difference between Dv50 and Dv10 of the first cathode material to Dv10 of the first cathode material is in the range of 1.2 to 2.5, optionally 1.5 to 2.0.

[0040] In each embodiment, the ratio of the difference between Dv90 and Dv50 of the second cathode material to Dv50 of the second cathode material is in the range of 0.8 to 1.5, optionally 1.0 to 1.3; and / or

[0041] The ratio of the difference between Dv50 and Dv10 of the second cathode material to Dv10 of the second cathode material is in the range of 6 to 12, optionally 8 to 10.

[0042] Controlling the particle size distribution of the first and second cathode materials within a suitable range is advantageous for the synergy effect between the first and second cathode materials, the improvement of the mechanical properties of the battery, and for increasing the compaction density of the positive electrode plate.

[0043] A second aspect of this application relates to a positive electrode plate comprising a positive current collector and a positive electrode film layer arranged on at least one surface of the positive current collector, wherein the positive electrode film layer comprises the active material of a positive electrode according to the first aspect.

[0044] In each embodiment, the thickness of the positive electrode film layer is 200 µm to 400 µm, optionally 220 µm to 300 µm.

[0045] By controlling the thickness of the positive electrode film layer within a suitable range, it is possible to provide sufficient active material at the positive electrode to improve the battery's energy density while simultaneously reducing the impact on solid-state lithium ion diffusion. This allows for a balance between the battery's energy density and performance.

[0046] In each embodiment, the compaction density of the positive electrode film layer is 2.9 g / m². 2 up to 3.5 g / m² 2 .

[0047] The compaction density of the positive electrode film layer is 2.9 g / m². 2 up to 3.5 g / m² 2 This is advantageous for improving the energy density of batteries.

[0048] A third aspect of this application concerns a secondary battery which includes the positive electrode plate according to the second aspect.

[0049] A fourth aspect of this application concerns an electrical device which includes the secondary battery according to the third aspect. DESCRIPTION OF THE FIGURES Fig. Figure 1 is a particle size distribution diagram of the active material of a positive electrode according to an embodiment of this application; Fig.Figure 2 is a schematic representation of a secondary battery according to an embodiment of this application; Fig. Figure 3 is an exploded view of the secondary battery according to an embodiment of this application, which is shown in Fig. 2 is shown; Fig. Figure 4 is a schematic representation of a battery module according to an embodiment of this application; Fig. Figure 5 is a schematic representation of a battery pack according to an embodiment of this application; Fig. Figure 6 is an exploded view of the battery pack according to an embodiment of this application, which is shown in Fig. 5 is shown; Fig. Figure 7 is a schematic representation of an electrical device with a secondary battery as a power source according to an embodiment of this application;

[0050] The markings in the figures are explained as follows: 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Secondary battery; 51 Housing; 52 Electrode assembly; 53 Cover plate. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0051] The embodiments of the active material of a positive electrode, the positive electrode plate, the secondary battery, and the electrical device of the present application are described in detail below with appropriate reference to the figures. Occasionally, however, unnecessary details may be omitted. For example, detailed explanations of generally known facts or repetitions of actually identical structures may be avoided. This is intended to avoid unnecessarily lengthening the following description and to facilitate understanding by those skilled in the art. Furthermore, the figures and the following description serve to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter of the claims.

[0052] The “range” disclosed in this application is defined by a lower bound and an upper bound. The specified range is determined by selecting a lower bound and an upper bound, the selected lower and upper bounds defining the limits of a particular range. The range thus defined can include or exclude limits and can be combined arbitrarily. That is, any lower bound can be combined with any upper bound to form a range. For example, if the ranges 60–120 and 80–110 are specified for a particular parameter, it is assumed that the ranges 60–110 and 80–120 are also understood. Furthermore, if the minimum range values ​​1 and 2 and the maximum range values ​​3, 4, and 5 are specified, then the following ranges are to be expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5.In this application, unless otherwise specified, the numerical ranges "ab" are shorthand representations of any combination of real numbers from a to b, where both a and b are real numbers. For example, the range "0-5" means that all real numbers between 0 and 5 listed in this document have been considered, with "0-5" serving merely as an abbreviated representation of these number combinations. Furthermore, when it is stated that a parameter is an integer ≥ 2, this means that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0053] Unless otherwise stated, all embodiments and optional embodiments of this application may be combined to form new technical solutions.

[0054] Unless otherwise stated, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0055] Unless otherwise stated, all steps of this application may be performed sequentially or in any order, with sequential order being preferred. For example, the procedure includes steps (a) and (b), which indicates that the procedure may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. The procedure may also include step (c), for example, which means that step (c) may be added to the procedure in any order. Thus, for example, the procedure may include steps (a), (b), and (c), steps (a), (c), and (b), or steps (c), (a), and (b), etc.

[0056] Unless otherwise stated, the terms "including" and "comprehensive" used in this application can be either open or closed. For example, the terms "comprehensive" and "including" can mean that other, unlisted components may also be included, or that only the listed components may be included.

[0057] Unless otherwise stated, the term "or" in this application is inclusive. For example, the expression "A or B" means "A, B, or both A and B". More specifically, each of the following conditions satisfies the "A or B" condition: A is true (or present) and B is false (or not present); A is false (or not present) and B is true (or present); or both A and B are true (or present).

[0058] Currently, ternary materials have become one of the most widely used active materials for the positive electrode of secondary lithium batteries due to their high theoretical specific capacity, high discharge plateau, and low cost. Common ternary materials, due to their solid structure, exhibit a solid-state diffusion pathway for metal ions. By fabricating ternary materials with a porous structure, this solid-state diffusion pathway can be shortened, thus improving battery performance. However, porous ternary materials can fracture during use, which can negatively impact the battery's electrochemical performance.Therefore, it is necessary to develop an active material for a positive electrode that takes into account both the performance and the mechanical strength of the battery equally in order to meet the application requirements of the next generation of electrochemical systems. [Active material of a positive electrode]

[0059] On this basis, the present application proposes an active material for a positive electrode, wherein the active material of a positive electrode is in the form of secondary particles formed by aggregation of primary particles, and at least some of the secondary particles have pores; and wherein the particle size distribution of the active material of a positive electrode, determined by laser diffraction method, is bimodal, with a difference between the position of the second peak and the position of the first peak of 1 µm to 13 µm.

[0060] In this document, the term "primary particles" refers to the particles of the active material of a positive electrode prior to their agglomeration.

[0061] In this document, the term "pore" refers to the cavity structure that is present inside the secondary particles of the active material of a positive electrode.

[0062] It is understood that the term “bimodal particle size distribution” means that the number of particles at the position of the first and second peaks in the particle size distribution diagram is significantly larger than the number of particles at other peak positions in the diagram; that is, there is a considerable amount of particles with two different particle sizes in the active material of a positive electrode.

[0063] In some embodiments, some secondary particles have pores.

[0064] In some embodiments, all secondary particles have pores.

[0065] In some embodiments, the inner diameter of the pores can be selected as follows: 0.1 µm, 0.2 µm, 0.4 µm, 0.5 µm, 0.6 µm, 0.8 µm, 1 µm, 1.2 µm, 1.4 µm, 1.5 µm, 1.6 µm, 1.8 µm, 2 µm, 2.2 µm, 2.4 µm, 2.5 µm, 2.6 µm, 2.8 µm, 3 µm or a value within a range formed by any two of the aforementioned points.

[0066] In some embodiments, the difference between the position of the second peak and the position of the first peak in the particle size distribution diagram can be chosen as follows: 1 µm, 2 µm, 3 µm, 4 µm, 5 µm, 6 µm, 7 µm, 8 µm, 9 µm, 10 µm, 11 µm, 12 µm, 13 µm or a value within a range formed by any two of the aforementioned points.

[0067] This document describes the creation of a particle size distribution diagram based on data obtained using the laser diffraction method. According to GB / T 19077-2016, Particle Size Distribution Method by Laser Diffraction, 0.1 g to 0.13 g of the active material sample from a positive electrode is weighed into a 50 ml beaker, 5 g of anhydrous ethanol is added, a magnetic stir bar approximately 2.5 mm long is inserted into the beaker, and the beaker is then sealed with cling film. The sample is subjected to ultrasonic treatment for 5 minutes and then transferred to a magnetic stirrer, where it is stirred at 500 rpm for more than 20 minutes. Two samples are taken from each product batch for testing. The test is performed using a Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, to obtain a volume-based particle size distribution diagram.

[0068] On the one hand, the presence of pores promotes the active material of a positive electrode having three-dimensional channels, which shortens the solid-state diffusion path of the lithium ions and improves the performance of the battery.On the other hand, the particle size distribution of the active material of a positive electrode is bimodal, which means that the combination of active materials for the positive electrode with different particle sizes not only contributes to improving the bulk density of the active material of a positive electrode, but above all, that the active materials for the positive electrode with different particle sizes can play a certain supporting role, which helps to improve the mechanical strength, reduce the risk of breakage of the active material of a positive electrode during use, improve the shear strength of the positive electrode plate and improve the mechanical strength of the battery.Furthermore, it is advantageous to limit the difference between the position of the first peak and the position of the second peak in the particle size distribution of the active material of the positive electrode to 3 µm to 13 µm in order to further improve the compaction density of the positive electrode plate and the electrical performance of the battery.

[0069] In some embodiments, the position of the first peak is between 1 µm and 5 µm. In some embodiments, the position of the first peak is between 1.5 µm and 4.5 µm. In some embodiments, the position of the first peak is at a value in the range of 1 µm, 1.5 µm, 2 µm, 2.5 µm, 3 µm, 3.5 µm, 4 µm, 4.5 µm, 5 µm, or between any two of the aforementioned points.

[0070] In some embodiments, the position of the second peak is between 6 µm and 14 µm. In some embodiments, the position of the second peak is between 8 µm and 12 µm. In some embodiments, the position of the second peak is at a value in the range of 6 µm, 6.5 µm, 7 µm, 7.5 µm, 8 µm, 8.5 µm, 9 µm, 9.5 µm, 10 µm, 10.5 µm, 11 µm, 11.5 µm, 12 µm, 12.5 µm, 13 µm, 13.5 µm, 14 µm, or between any two of the aforementioned points.

[0071] By controlling the positions of the first and second peaks within a suitable range, the battery exhibits a high volumetric energy density as well as excellent performance and mechanical strength.

[0072] In some embodiments, the secondary particles comprise multiple pores formed by the spaces between the primary particles, with an inner diameter of 0.1 µm to 0.6 µm. In some embodiments, the secondary particles comprise multiple pores formed by the spaces between the primary particles, with an inner diameter of 0.2 µm to 0.4 µm. In some embodiments, the secondary particles comprise multiple pores formed by the spaces between the primary particles, the inner diameter of which can be selected as follows: 0.1 µm, 0.15 µm, 0.2 µm, 0.25 µm, 0.3 µm, 0.35 µm, 0.4 µm, 0.45 µm, 0.5 µm, 0.55 µm, 0.6 µm or a value within a range formed by any two of the aforementioned points.

[0073] In some embodiments, the secondary particles comprise multiple pores formed by the spaces between the primary particles, the multiple pores being distributed throughout the interior of the secondary particles and exhibiting an annular distribution in a section through the center of gravity of the secondary particles.

[0074] In some embodiments, the secondary particles further comprise pores located within the primary particles, wherein the inner diameter of the pores is 0.01 µm to 0.06 µm. In some embodiments, the secondary particles further comprise pores located within the primary particles, wherein the inner diameter of the pores can be selected as follows: 0.01 µm, 0.02 µm, 0.03 µm, 0.04 µm, 0.05 µm, 0.06 µm, or a value within a range formed by any two of the aforementioned points.

[0075] In some embodiments, the secondary particles comprise a single hollow pore in a central position, surrounded by primary particles, wherein the inner diameter of the pore is 0.5 µm to 3 µm. In some embodiments, the secondary particles comprise a single hollow pore in a central position, surrounded by primary particles, wherein the inner diameter of the pore is 0.8 µm to 1.2 µm. In some embodiments, the secondary particles comprise a single hollow pore in a central position, surrounded by primary particles, wherein the inner diameter of the pore can be selected as follows: 0.5 µm, 1 µm, 1.5 µm, 2 µm, 2.5 µm, 3 µm, or a value within a range formed by any two of the aforementioned points.

[0076] In this document, the term "inner diameter of a pore" refers to the longest straight-line distance between any two points on the circumference of a single cavity within the secondary particles of the active material of a positive electrode.

[0077] In this document, the internal diameter of the pores can be tested using all methods known in the industry. As an example, conductive adhesive is applied to the sample stage, a powdered sample of the active material of a positive electrode is evenly distributed on the conductive adhesive, non-adherent powder is blown away with a bellows, a gold coating is sputtered on, and argon plasma is used to prepare a cross-section of the powdered sample. Scanning electron microscopy (SEM) images of the powdered sample are obtained under conditions of an accelerating voltage of 10 kV and an emission current of 10 mA. The internal diameter of the pores is measured from the SEM images. At least three samples are measured, with at least 50 pores measured from each sample. The arithmetic mean is used as the internal diameter of the pores for the sample.

[0078] Pores with different distribution patterns have different internal diameters, which promotes the formation of three-dimensional channels in the active material of a positive electrode, shortens the solid-state diffusion path of the lithium ions, and improves the battery's performance.

[0079] In some embodiments, the active material of a positive electrode has the following chemical formula: Li a Ni x M1 y M2 1-x-y O2,

[0080] M1 and M2 comprise one or more of the elements Co, Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg and Nb, with 0.8≤a≤1.2, 0.55≤x≤1.0 and 0≤y≤0.45. In some embodiments, the following apply: 0.8≤a≤1.2, 0.95≤x≤0.995 and 0≤y≤0.05.

[0081] The use of the aforementioned materials ensures that the active material of a positive electrode has a high specific capacity, resulting in a battery with high energy density.

[0082] In some embodiments, the average particle size D of the primary particles of the active material of a positive electrode is 0.1 µm to 0.8 µm. In some embodiments, the average particle size D of the primary particles of the active material of a positive electrode is 0.2 µm to 0.5 µm. In some embodiments, the average particle size D of the primary particles of the active material of a positive electrode can be selected as follows: 0.1 µm, 0.15 µm, 0.2 µm, 0.25 µm, 0.3 µm, 0.35 µm, 0.4 µm, 0.45 µm, 0.5 µm, 0.55 µm, 0.6 µm, 0.65 µm, 0.7 µm, 0.75 µm, 0.8 µm or a value within a range formed by any two of the aforementioned points.

[0083] This document describes how to test the average particle size D of the primary active material particles of a positive electrode using all methods known in the industry. As an example, after imaging with a scanning electron microscope (ZEISS Sigma-02-33, Germany, 500x magnification), 200 to 600 fully formed, non-overlapping primary active material particles of a positive electrode are randomly selected from the electron micrographs. The largest diameter of each pore in the primary particles is then measured and recorded in the microscopic images. The average value is used as the average particle size D.

[0084] By controlling the average particle size of the primary particles of the active material of a positive electrode within a suitable range, secondary particles of the active material of a positive electrode with a suitable range can be formed, giving the battery a high volumetric energy density, excellent performance and high mechanical strength.

[0085] In some embodiments, the Dv50 of the active material of a positive electrode is 9 µm to 15 µm. In some embodiments, the Dv50 of the active material of a positive electrode is 10 µm to 12 µm. In some embodiments, the Dv50 of the active material of a positive electrode can be selected as follows: 9 µm, 9.5 µm, 10 µm, 10.5 µm, 11 µm, 11.5 µm, 12 µm, 12.5 µm, 13 µm, 13.5 µm, 14 µm, 14.5 µm, 15 µm, or a value within a range formed by any two of the aforementioned points.

[0086] This document describes how the Dv50 of the active material of a positive electrode can be tested using all methods known in the industry. For example, according to GB / T 19077-2016, the particle size distribution method using laser diffraction involves weighing 0.1 g to 0.13 g of the active material sample to be tested into a 50 ml beaker, adding 5 g of anhydrous ethanol, inserting a magnetic stir bar approximately 2.5 mm long into the beaker, and then sealing it with cling film. The sample is subjected to ultrasonic treatment for 5 minutes and then transferred to a magnetic stirrer, where it is stirred at 500 rpm for more than 20 minutes. Two samples are taken from each product batch for testing. The tests are performed using a Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK.Dv50 is the particle size that corresponds to a cumulative volume distribution fraction of 50% of the secondary particles of the active material of a positive electrode.

[0087] Controlling the active material of a positive electrode within a suitable area gives the battery a high volumetric energy density, excellent performance, and mechanical strength.

[0088] In some embodiments, the specific surface area of ​​the active material of a positive electrode is 0.1 m². 2 / g up to 1.0 m 2 / g. In some embodiments, the specific surface area of ​​the active material of a positive electrode is 0.2 m². 2 / g up to 0.5 m 2 / g. In some embodiments, the specific surface area of ​​the active material of a positive electrode is 0.1 m². 2 / g, 0.2 m 2 / g, 0.3 m 2 / g, 0.4 m 2 / g, 0.5 m 2 / g, 0.6 m 2 / g, 0.7 m 2 / g, 0.8 m 2 / g, 0.9 m 2 / g, 1.0 m 2 / g or a value within a range formed by any two of the points mentioned above.

[0089] This document describes how to test the specific surface area of ​​the active material of a positive electrode using all methods known in the industry. As an example, reference is made to GB / T 19587-2017 "Determination of the specific surface area of ​​solids by gas adsorption using the BET method." The measurement was performed using a TriStar II 3020 instrument. The active material of a positive electrode was dispersed in a dispersant (ethanol), sonicated for 30 minutes, the resulting material was dried in a vacuum drying oven, and finally, the specific surface area of ​​the active material of the positive electrode was measured using a surface analyzer.

[0090] By controlling the specific surface area of ​​the active material of a positive electrode within a suitable range, the battery can achieve high volumetric energy density, excellent performance, and high mechanical strength.

[0091] In some embodiments, the active material of a positive electrode comprises a first cathode material and a second cathode material.

[0092] It is understood that the first and second cathode materials have different dimensions. The combined use of the first and second cathode materials has a synergistic effect, increasing the density of the positive electrode plate and improving the mechanical performance and cycle stability of the battery.

[0093] In some embodiments, the first cathode material has pores, and the second cathode material has a solid structure.

[0094] In some embodiments, the first cathode material has a solid structure, and the second cathode material has pores.

[0095] In some embodiments, both the first and the second cathode material have pores.

[0096] The presence of pores can shorten the diffusion path of lithium ions in the solid phase, improve the battery's performance, and expose more (010) crystal planes, thereby creating more reactive sites and improving the material's specific capacity and energy density.

[0097] In some embodiments, the mass ratio A of the first cathode material to the second cathode material and the porosity B of the active material of a positive electrode satisfy the following relationship: 0 ≤ |B - A×0.4 - (1-A)×0.2| ≤ 1. In some embodiments, the relationship 0 ≤ |B - A×0.4 - (1-A)×0.2| ≤ 1 between the mass ratio A of the first cathode material to the second cathode material and the porosity B of the active material of a positive electrode can take the following values: 0; 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9; 1.0 or a value within a range formed by any two of the aforementioned points.

[0098] In this document, the relationship “|B - A×0.4 - (1-A)×0.2|” is represented as the absolute value of the numerical value of B - A×0.4 - (1-A)×0.2.

[0099] The targeted adjustment of the mass ratio of the first and second cathode materials, in order to ensure the aforementioned relationship to the porosity of the active material of a positive electrode, makes it possible to provide sufficient pores to shorten the solid-state diffusion path of the lithium ions and improve the performance of the battery, while at the same time the interaction force between the first and second cathode materials can be adjusted to optimize the mechanical properties of the battery.

[0100] In some embodiments, the mass ratio A of the first cathode material to the second cathode material is 1.5 to 9. In some embodiments, the mass ratio A of the first cathode material to the second cathode material is 2 to 8. In some embodiments, the mass ratio A of the first cathode material to the second cathode material is 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, or a value within a range formed by any two of the aforementioned points.

[0101] The mass ratio of the first cathode material to the second cathode material is controlled within a suitable range, taking into account both the compaction density of the positive electrode plate and the mechanical strength of the battery.

[0102] In some embodiments, the porosity B of the active material of a positive electrode is 0.15% to 0.45%. In some embodiments, the porosity B of the active material of a positive electrode is 0.25% to 0.35%. In some embodiments, the porosity B of the active material of a positive electrode is 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or a value within a range defined by any two of the aforementioned points.

[0103] By controlling the porosity of the active material of a positive electrode in a suitable range, sufficient pores can be provided to shorten the solid-state diffusion path of the lithium ions and improve the performance of the battery, while avoiding or reducing the influence of the pores on the mechanical strength of the active material of a positive electrode.

[0104] In some embodiments, the first cathode material and the second cathode material each have the following chemical formula independently of each other: Li a Ni x M1 y M2 1-x-y O2,

[0105] M1 and M2 comprise one or more of the elements Co, Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg and Nb, with 0.8≤a≤1.2, 0.55≤x≤1.0 and 0≤y≤0.45. In some embodiments, the following apply: 0.8≤a≤1.2, 0.95≤x≤0.995 and 0≤y≤0.05.

[0106] Both the first and the second cathode materials with the aforementioned chemical formulas exhibit a high volumetric energy density.

[0107] In some embodiments, the Dv50 of the first cathode material is 8 µm to 18 µm. In some embodiments, the Dv50 of the first cathode material is 10 µm to 12 µm. In some embodiments, the Dv50 of the first cathode material is 8 µm, 9 µm, 10 µm, 11 µm, 12 µm, 13 µm, 14 µm, 15 µm, 16 µm, 17 µm, 18 µm, or a value within a range formed by any two of the aforementioned points.

[0108] In some embodiments, the Dv50 of the second cathode material is 0.8 µm to 5 µm. In some embodiments, the Dv50 of the second cathode material is 1 µm to 3 µm. In some embodiments, the Dv50 of the second cathode material is 0.8 µm, 1.5 µm, 2 µm, 2.5 µm, 3 µm, 3.5 µm, 4 µm, 4.5 µm, 5 µm, or a value within a range formed by any two of the aforementioned points.

[0109] In this document, the test procedures for the Dv50 of the first cathode material and the Dv50 of the second cathode material are the same as those for the Dv50 of the active material of a positive electrode.

[0110] Controlling the Dv50 value of the first cathode material and the Dv50 value of the second cathode material within a suitable range is advantageous for the synergy effect between the first cathode material and the second cathode material and contributes to improving the volumetric energy density and the mechanical properties of the battery.

[0111] In some embodiments, the ratio of the difference between Dv90 and Dv50 of the first cathode material to Dv50 of the first cathode material is 0.6 to 1.2. In some embodiments, the ratio of the difference between Dv90 and Dv50 of the first cathode material to Dv50 of the first cathode material is 0.8 to 1.0. In some embodiments, the ratio of the difference between Dv90 and Dv50 of the first cathode material to Dv50 of the first cathode material is 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, or a value within a range formed by any two of the aforementioned points.

[0112] In some embodiments, the ratio of the difference between Dv50 and Dv10 of the first cathode material to Dv10 of the first cathode material is between 1.2 and 2.5. In some embodiments, the ratio of the difference between Dv50 and Dv10 of the first cathode material to Dv10 of the first cathode material is between 1.5 and 2.0. In some embodiments, the ratio of the difference between Dv50 and Dv10 of the first cathode material to Dv10 of the first cathode material is 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, or a value within a range formed by any two of the aforementioned points.

[0113] In some embodiments, the ratio of the difference between Dv90 and Dv50 of the second cathode material to Dv50 of the second cathode material is 0.8 to 1.5. In some embodiments, the ratio of the difference between Dv90 and Dv50 of the second cathode material to Dv50 of the second cathode material is 1.0 to 1.3. In some embodiments, the ratio of the difference between Dv90 and Dv50 of the second cathode material to Dv50 of the second cathode material is 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, or a value within a range formed by any two of the aforementioned points.

[0114] In some embodiments, the ratio of the difference between Dv50 and Dv10 of the second cathode material to Dv10 of the second cathode material satisfies 6 to 12. In some embodiments, the ratio of the difference between Dv50 and Dv10 of the second cathode material to Dv10 of the second cathode material satisfies 8 to 10. In some embodiments, the ratio of the difference between Dv50 and Dv10 of the second cathode material to Dv10 of the second cathode material satisfies 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, or a value within a range formed by any two of the aforementioned points.

[0115] In this document, Dv90 is the particle size corresponding to a cumulative volume distribution of 90% for the secondary particles of the first cathode material / second cathode material, and Dv10 is the particle size corresponding to a cumulative volume distribution of 10% for the secondary particles of the first cathode material / second cathode material.

[0116] Controlling the particle size distribution of the first and second cathode materials within a suitable range is advantageous for the synergy effect between the first and second cathode materials, the improvement of the mechanical properties of the battery, and for increasing the compaction density of the positive electrode plate. [Positive electrode]

[0117] The positive electrode plate comprises a positive current collector and a positive electrode film layer arranged on at least one surface of the positive current collector, wherein the positive electrode film layer comprises the active material of a positive electrode according to some embodiments.

[0118] For example, the positive current collector has two surfaces opposite each other in its thickness direction, and the positive electrode layer is arranged on one or both of the two opposite surfaces of the positive current collector.

[0119] In some embodiments, the areal density of the positive electrode film layer is 24 mg / cm². 2 up to 46 mg / cm² 2 In some embodiments, the areal density of the positive electrode film layer can be selected as follows: 24 mg / cm² 2 , 25 mg / cm 2 , 26 mg / cm 2 , 28 mg / cm 2 , 30 mg / cm 2 , 32 mg / cm2 , 34 mg / cm 2 , 35 mg / cm 2 , 36 mg / cm 2 , 38 mg / cm 2 , 40 mg / cm 2 , 42 mg / cm 2 , 44 mg / cm 2 , 45 mg / cm 2 , 46 mg / cm 2 or a value within a range formed by any two of the points mentioned above.

[0120] The areal density of the positive electrode film layer is determined by measuring the coating weight (g) and the coating area (cm²). 2 The density of the positive electrode film layer on one side is determined (number of measuring points > 14). The areal density of the positive electrode film layer is calculated as follows: coating weight of the positive electrode film layer (g) / coating area of ​​the positive electrode film layer (cm²). 2 ).

[0121] In some embodiments, the thickness of the positive electrode film layer is 200 µm to 400 µm. In some embodiments, the thickness of the positive electrode film layer is 220 µm to 300 µm. In some embodiments, the thickness of the positive electrode film layer can be selected as follows: 200 µm, 220 µm, 240 µm, 250 µm, 260 µm, 280 µm, 300 µm, 320 µm, 340 µm, 350 µm, 360 µm, 380 µm, 400 µm, or a value within a range formed by any two of the aforementioned points.

[0122] By controlling the thickness of the positive electrode film within a suitable range, it is possible to provide sufficient active material at the positive electrode to improve the battery's energy density while simultaneously reducing the impact on solid-state lithium ion diffusion. This allows for a balance between the battery's energy density and performance.

[0123] In some embodiments, the compaction density of the positive electrode film layer is 2.9 g / m². 2 up to 3.5 g / m² 2 In some embodiments, the compaction density of the positive electrode film layer can be selected as follows: 2.9 g / m² 2 , 3.0 g / m² 2 , 3.1 g / m³ 2 , 3.2 g / m³ 2 , 3.3 g / m³ 2 , 3.4 g / m² 2 , 3.5 g / m² 2 or a value within a range formed by any two of the points mentioned above.

[0124] In this text, the density of the positive electrode film layer of the positive electrode plate can be tested using all known test methods. As an example, the density of the positive electrode film layer of the positive electrode plate is determined by measuring the areal density (g / cm²). 2The density of the positive electrode film layer is determined by the thickness (cm) of the one-sided positive electrode film layer (number of measuring points > 14). Specifically, the density of the positive electrode film layer corresponds to the areal density of the one-sided positive electrode film layer (g / cm²). 2 ) / Thickness of the positive electrode film layer (cm).

[0125] Positive electrode plates with a higher compaction density of the positive electrode film layer are advantageous for increasing the volumetric energy density.

[0126] In some embodiments, the positive 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 can comprise a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector can be produced by depositing metallic materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) onto polymer substrates (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0127] In some embodiments, the positive electrode film layer may optionally contain a binder. For example, the binder may contain at least one of the following substances: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene propylene terpolymer, PVDF-hexafluoropropylene tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0128] In some embodiments, the positive electrode film layer may optionally contain a conductive material. For example, the conductive material may contain at least one of the following materials: superconducting carbon, carbon black, carbon black, Ketjen black, carbon nanoparticles, carbon nanotubes, graphene, and carbon nanofibers.

[0129] In some embodiments, the positive electrode plate can be produced as follows: the aforementioned components for producing the positive electrode plate, such as the active material of a positive electrode, the conductive agent, the binder, and any other components, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode suspension; the positive electrode suspension is applied to the positive current collector, and after process steps such as drying and cold pressing, the positive electrode plate is obtained. [Negative electrode]

[0130] A negative electrode comprises a negative current collector and a negative electrode film layer arranged on at least one surface of the negative current collector.

[0131] For example, the negative current collector has two surfaces opposite each other in its thickness direction, and the negative electrode film layer is arranged on one or both of the two opposite surfaces of the negative current collector.

[0132] In some embodiments, the negative 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 can comprise a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector can be manufactured by depositing metallic materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) onto polymer substrates (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0133] In some embodiments, the active material of the negative electrode may be a negative electrode active material known to those skilled in the art and used in batteries. For example, the negative electrode active material may comprise at least one of the following: synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials may be selected from at least one of the following: elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials may be selected from at least one of the following: elemental tin, tin oxides, and tin alloys.However, the present application is not limited to these materials; other traditional materials that can be used as active materials for the negative electrode of a battery may also be used. These active materials for negative electrodes may be used alone or in combination with one or more.

[0134] In some embodiments, the active material of the negative electrode contains silicon monoxide.

[0135] In some embodiments, the mass fraction of silicon monoxide, based on the total mass of the active material of the negative electrode, is 20% to 100%. In some embodiments, the mass fraction of silicon monoxide, based on the total mass of the active material of the negative electrode, is 50% to 100%.

[0136] In some embodiments, the negative electrode film layer may optionally contain a binder for the negative electrode. At least one of the following substances may be selected as the binder: 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).

[0137] In some embodiments, the negative electrode film layer may optionally contain a conductive material. At least one of the following materials may be selected as the conductive material: superconducting carbon, carbon black, carbon black, Ketjen black, carbon nanoparticles, carbon nanotubes, graphene, and carbon nanofibers.

[0138] In some embodiments, the negative electrode film layer also contains other additives, such as thickening agents (e.g. sodium carboxymethylcellulose (CMC-Na)), etc.

[0139] In some embodiments, the negative electrode plate can be produced as follows: the aforementioned components for producing the negative electrode plate, such as the active material of the negative electrode, the conductive agent, the binder, and any other components, are dispersed in a solvent (e.g., deionized water) to form a negative electrode suspension; the negative electrode suspension is applied to the negative current collector, and after process steps such as drying and cold pressing, the negative electrode plate is obtained. [Separator film]

[0140] In some embodiments, the secondary battery also contains a separator film. Any known separator film with a porous structure and good chemical and mechanical stability can be selected.

[0141] In some embodiments, the separator film material can be selected from at least one of the following: glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film can be a single-layer film or a multi-layer composite film. If the separator film is a multi-layer composite film, the materials of the individual layers can be the same or different.

[0142] In some embodiments, the positive electrode plate, the negative electrode plate and the separator film can be processed into an electrode assembly by a winding process or a stacking process.

[0143] In some embodiments, the secondary battery comprises the negative electrode plate, the separator foil, the electrolyte, and the positive electrode plate according to some embodiments.

[0144] In some embodiments, the secondary battery includes a lithium secondary battery.

[0145] In some embodiments, the energy density of the secondary battery is 700 Wh / L to 900 Wh / L.

[0146] In some embodiments, the secondary battery may include a casing. This casing can be used to encapsulate the aforementioned electrode assembly and the electrolyte.

[0147] In some embodiments, the secondary battery casing can be a rigid housing, e.g., a housing made of hard plastic, aluminum, steel, etc. The secondary battery casing can also be a flexible housing, e.g., a bag-shaped soft packaging. Materials for flexible housings can include plastics such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0148] The shape of the secondary battery according to the present application can be cylindrical, rectangular, or any other shape. For example, shows Fig. 2 a secondary battery 5 with a rectangular structure as an example.

[0149] In some embodiments, with reference to Fig.3, the casing comprises a housing 51 and a cover plate 53. The housing 51 can comprise a base plate and a side plate connected to the base plate, the base plate and side plate forming a receiving space. The housing 51 has an opening connected to the receiving space, and the cover plate 53 can cover the opening to close the receiving space. The positive electrode plate, the negative electrode plate, and the separator film can be manufactured into an electrode assembly 52 by a winding or a stacking process. The electrode assembly 52 is encapsulated in the receiving space. The electrolyte permeates the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, which the person skilled in the art can select according to the specific requirements.

[0150] In some embodiments, secondary batteries can be assembled into a battery module. The number of secondary batteries contained in the battery module can be one or more, which a person skilled in the art can select depending on the application and capacity of the battery module.

[0151] Fig. Figure 4 shows a battery module 4 as an example. As shown from Fig. As shown in Figure 4, several secondary batteries 5 can be arranged longitudinally within battery module 4. Of course, it can also be arranged in any other way. Furthermore, the multiple secondary batteries 5 can be secured with fastening elements.

[0152] Alternatively, the battery module 4 can also include a housing with a receiving space in which a large number of secondary batteries 5 can be received.

[0153] In some embodiments, the aforementioned battery modules can further be assembled into a battery pack. The number of battery modules contained in the battery pack can be one or more, which can be selected by a person skilled in the art depending on the application and capacity of the battery pack.

[0154] Fig. 5 and Fig. Figure 6 shows an example of a battery pack 1. In the Fig. 5 and Fig. Figure 6 shows that the battery pack 1 can comprise a battery housing and a plurality of battery modules 4 arranged within the battery housing. The battery housing consists of an upper housing part 2 and a lower housing part 3. The upper housing part 2 can cover the lower housing part 3, thus forming an enclosed space for the battery modules 4. The multiple battery modules 4 can be arranged arbitrarily within the battery housing.

[0155] Furthermore, the present application also provides an electrical device comprising at least one of the secondary batteries, battery modules, or battery packs provided for in this application. The secondary battery, battery module, or battery pack can be used as a power source or as an energy storage unit for the electrical device. Electrical devices include, among others, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid vehicles, plug-in hybrid vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, and energy storage systems, etc.

[0156] Depending on the requirements of its use, the secondary battery, battery module or battery pack can be selected for the electrical device.

[0157] Fig.Figure 7 shows an electrical device as an example. The electrical consumer is a pure electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, etc. To meet the electrical consumer's requirements for high power and high energy density of the secondary battery, battery packs or battery modules can be used.

[0158] Another example of such a device would be a mobile phone, a tablet, a laptop, etc. This type of device typically requires a lightweight and thin design and can use a secondary battery as a power source. Examples of implementation

[0159] The embodiments described below are examples of the present application. These embodiments are examples and serve only to illustrate this application; they are not to be construed as limiting this application. Unless a specific technology or conditions are indicated in the embodiments, the technologies or conditions described in the technical literature or the product manual apply. Unless the manufacturers of the reagents or instruments used are specified, they are exclusively commercially available products. I. Manufacturing process Example 11) Production of the active material of a positive electrode Production of the first cathode material:

[0160] A nickel-cobalt-manganese solution with a molar ratio of nickel:cobalt:manganese = 96:1:3 is prepared and adjusted to a concentration of 2 mol / L. Nickel sulfate, cobalt sulfate, and manganese sulfate, respectively, serve as starting materials for soluble nickel, cobalt, and manganese. The molar concentration of manganese ions is 0.25 mol / L. Additionally, a 3 mol / L sodium hydroxide solution and a 5.5 mol / L ammonia solution are provided.

[0161] Under a nitrogen atmosphere, the aforementioned nickel-cobalt-manganese solution, the sodium hydroxide solution, and the ammonia solution are simultaneously added to a reactor for precipitation. The rotational speed is set to 400 rpm, the temperature to 110 °C, and the reaction time to 8 hours. The pH of the system is adjusted to 9.5, and the concentration of the ammonia solution to 6 mol / L. After completion of the precipitation reaction, the reaction mixture is transferred to a slurry tank for aging and washing. Following dehydration, the mixture is dried for 9 hours at 115 °C in a drying oven. Sieving and demagnetization yield a precursor exhibiting numerous ring-shaped pores.

[0162] The precursor and lithium hydroxide are mixed uniformly in a specific ratio, with a molar Li / Me ratio of 1.03; Me denotes the total molar content of nickel, cobalt and manganese.

[0163] The uniformly mixed material is placed in an oven and calcined at 720 °C for 20 hours at a heating rate of 3 °C / min. The atmosphere has an oxygen content of ≥ 98%. The material is then cooled in the oven, yielding a base material.

[0164] Under a nitrogen atmosphere, the base material, cobalt boride, and titanium boride are mixed in a high-speed mixer at a mass ratio of 1:0.015:0.0041. The mixture is then calcined in an oven at a calcination temperature of 320 °C for 5 hours under a nitrogen atmosphere to obtain a product. The product is then subjected to a water wash for 30 minutes, centrifuged, filtered, and subsequently dried by vibration. This process yields the first cathode material, which comprises numerous pores formed by the spaces between the primary particles of the first cathode material. Production of the second cathode material:

[0165] A nickel-cobalt-manganese solution with a molar ratio of nickel:cobalt:manganese = 96:1:3 is prepared and adjusted to a concentration of 2.0 mol / L. Nickel sulfate, cobalt sulfate, and manganese sulfate, respectively, serve as starting materials for the soluble nickel, cobalt, and manganese. Additionally, a 2 mol / L sodium hydroxide solution and a 6 mol / L ammonia solution are provided.

[0166] The aforementioned nickel-cobalt-manganese solution, the sodium hydroxide solution, and the ammonia solution are simultaneously added to a reactor for a joint precipitation reaction. The rotational speed is set to 850 rpm, the temperature to 55 °C, and the time to 5 hours. The flow rates of the three solutions are set as follows: sodium hydroxide solution 0.6 L / min, ammonia solution 0.6 L / min, and nickel-cobalt-manganese solution 0.3 L / min. The pH of the system is set to 10.3.

[0167] After the precipitation reaction is complete, the resulting precipitate is transferred to a slurry tank for aging and washing. After dewatering, it is dried in a drying oven at 110 °C for 12 hours. Sieving and demagnetization yield a precursor for the active material of a positive electrode.

[0168] The precursor and lithium hydroxide are mixed uniformly in a specific ratio, with a molar Li / Me ratio of 1.03; Me denotes the total molar content of nickel, cobalt and manganese.

[0169] The uniformly mixed material is placed in an oven and calcined at 700 °C for 15 hours at a heating rate of 3 °C / min. The atmosphere has an oxygen content of ≥ 98%. The material is then cooled in the oven, yielding a base material.

[0170] Under a nitrogen atmosphere, the base material, cobalt boride, and titanium boride are mixed in a high-speed mixer at a mass ratio of 1:0.015:0.0041. The mixture is then calcined in an oven at a calcination temperature of 300°C for 4 hours under a nitrogen atmosphere to obtain a product. The product is then washed with water for 30 minutes, centrifuged, filtered, and subsequently vibration-dried. This process yields the second cathode material with a solid structure.

[0171] Production of the active material of a positive electrode: The first and second cathode materials are mixed uniformly in a mass ratio of 6:1 to obtain the active material of a positive electrode. 2) Production of the positive electrode plate

[0172] The aforementioned active material of a positive electrode, conductive carbon black and the binder polyvinylidene fluoride (PVDF), are added to N-methylpyrrolidone in a mass ratio of 97:1:2 and mixed and stirred for 0.5 to 6 hours to obtain a suspension for the positive electrode. The suspension is then applied evenly to the positive current collector made of aluminum foil to form the positive electrode film layer. After drying, cold pressing, and cutting, the positive electrode plate is obtained. 3) Production of the negative electrode plate

[0173] Synthetic graphite doped with silicon dioxide (SiO₂), conductive carbon black, carbon nanotubes (CNTs), the binder styrene-butadiene rubber (SBR), and the thickener sodium carboxymethylcellulose (CMC) are dispersed in deionized water in a weight ratio of 94.5:1:0.375:2.8:1.325, with the mass fraction of SiO₂ being 30% based on the mass of synthetic graphite. The mixture is stirred for 5 hours to obtain a suspension for the negative active material layer. This suspension is applied evenly in layers to the negative current collector made of copper foil. After drying, cold pressing, and cutting, the negative electrode plate is obtained. 4) Electrolyte

[0174] In a glovebox with an argon atmosphere (H₂O < 0.1 ppm, O₂ < 0.1 ppm), the lithium salt LiPF₆ / LiFSI is dissolved in an organic solvent mixture of ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, and fluoroethylene carbonate (volume ratio 1:1:1:1) and stirred until homogeneity is achieved. An electrolyte with a lithium salt concentration of 1 mol / L is obtained. 5) Separator film

[0175] A polypropylene film is used as the base membrane. A 1 µm thick aluminum oxide layer (CCS) and a 1 µm thick polyvinylidene fluoride layer (PCS) are applied to this membrane. 6) Battery production

[0176] The positive electrode plate, the separator foil, and the negative electrode plate are stacked on top of each other in that order, with the separator foil positioned between the positive and negative plates for insulation. The stack is then wound into a bare cell. Tabs are welded to this bare cell, and the cell is inserted into an aluminum casing. It is then dried at 80 °C to remove water. The electrolyte is added, and the casing is sealed, resulting in an uncharged battery. The uncharged battery then undergoes a series of processes, including settling, hot and cold pressing, forming, shaping, and capacity testing, to produce the lithium battery product according to embodiment 1. Exemplary embodiments 2 to 4

[0177] The batteries of embodiments 2 to 4 are manufactured in a similar manner to the battery of embodiment 1. However, the manufacturing process of the active material of a positive electrode is adapted such that the inner pore diameter of the first cathode material varies. The specific parameters are listed in Table 1. Example 5

[0178] The battery of embodiment 5 is manufactured in a similar manner to the battery of embodiment 1. However, the manufacturing process of the first cathode material is adapted such that the first cathode material comprises a single hollow pore in a central position, which is enclosed by primary particles of the first active material of the positive electrode. The specific manufacturing process is as follows: A nickel-cobalt-manganese solution with a molar ratio of nickel, cobalt, and manganese of 96:1:3 is prepared and adjusted to 1.9 mol / L. Nickel sulfate, cobalt sulfate, and manganese sulfate, respectively, serve as starting materials for the soluble nickel, cobalt, and manganese. A 2 mol / L sodium hydroxide solution and a 6 mol / L ammonia solution are provided. A dispersion of carbon spheres with a mass concentration of 10 g / L is prepared and added to the reactor, where it is stirred at 850 rpm for 120 minutes until a uniform dispersion is achieved. Carbon sphere specifications: diameter 0.20 µm.

[0179] The aforementioned nickel-cobalt-manganese solution, the sodium hydroxide solution, and the ammonia solution are simultaneously added to a reactor for a joint precipitation reaction. The rotational speed is set to 850 rpm, the temperature to 55 °C, and the time to 5 hours. The flow rates of the three solutions are set as follows: sodium hydroxide solution 0.6 L / min, ammonia solution 0.6 L / min, and nickel-cobalt-manganese solution 0.3 L / min. The pH of the system is set to 10.3. The ratio of the weight of the carbon spheres to the total weight of nickel, cobalt, and manganese in the nickel-cobalt-manganese solution is 2:18.

[0180] After the precipitation reaction is complete, the reaction mixture flows into an aging vessel. A specific amount of a washing additive is added, and the mixture is stirred for one hour. The material is then dewatered, washed, dewatered again, dried, sieved, and demagnetized. A precursor for the active material of a positive electrode with carbon spheres at its center is obtained.

[0181] The precursor of the active material of a positive electrode and lithium carbonate are uniformly mixed in a specific ratio, with a molar Li / Me ratio of 1.02; Me denotes the total molar content of nickel, cobalt and manganese.

[0182] The uniformly mixed material is placed in an oven with an oxygen atmosphere, heated at a rate of 5 °C / min, and held at 705 °C for 6 hours. The atmosphere has an oxygen content of ≥ 98%. Cooling then takes place in the oven.

[0183] The calcined material is crushed by roller grinding, ultracentrifugally milled, and then sieved through a 400-mesh sieve. This yields the first cathode material, which comprises a single hollow pore in a central position, surrounded by primary particles of the first active material of the positive electrode. Exemplary embodiments 6 to 31

[0184] The batteries of embodiments 6 to 31 are manufactured in a similar manner to the battery of embodiment 5. However, the manufacturing process of the active material of a positive electrode is adapted. The specific parameters are listed in Table 1. Example 32

[0185] The battery of embodiment 32 is manufactured in a similar manner to the battery of embodiment 5. However, the manufacturing process of the second cathode material is adapted such that the second cathode material comprises a single hollow pore in a central position, which is enclosed by primary particles of the second active material of the positive electrode. The specific parameters are listed in Table 1. Example 33

[0186] The battery of embodiment 33 is manufactured in a similar manner to the battery of embodiment 32. However, the manufacturing process of the second cathode material is adapted such that the second cathode material comprises numerous pores formed by the spaces between the primary particles of the second cathode material. The specific parameters are listed in Table 1. Example 34

[0187] The battery of embodiment 34 is manufactured in a similar manner to the battery of embodiment 2. However, the manufacturing process of the second cathode material is adapted such that the second cathode material comprises a single hollow pore in a central position, which is enclosed by primary particles of the first active material of the positive electrode. The specific parameters are listed in Table 1. Example 35

[0188] The battery of embodiment 35 is manufactured in a similar manner to the battery of embodiment 34. However, the manufacturing process of the second cathode material is adapted such that the second cathode material comprises numerous pores formed by the spaces between the primary particles of the second cathode material. The specific parameters are listed in Table 1. Example 36

[0189] The battery of embodiment 36 is manufactured in a similar manner to the battery of embodiment 32. However, the manufacturing process of the first cathode material is adapted so that the first cathode material has a solid structure. The specific parameters are listed in Table 1. Example 37

[0190] The battery of embodiment 37 is manufactured in a similar manner to the battery of embodiment 33. However, the manufacturing process of the first cathode material is adapted so that the first cathode material has a solid structure. The specific parameters are listed in Table 1. Comparative example 1

[0191] The battery of Comparative Example 1 is manufactured in a similar manner to the battery of Exemplary Example 5. However, the active material of a positive electrode comprises only the first hollow cathode material and not the second cathode material. The specific parameters are listed in Table 1. Comparative example 2

[0192] The battery of comparative example 2 is manufactured in a similar manner to the battery of embodiment 33. However, the active material of a positive electrode comprises only the second cathode material with ring-shaped pores and not the first cathode material. The specific parameters are listed in Table 1. Comparative example 3

[0193] The battery of comparative example 3 is manufactured in a similar manner to the battery of embodiment 2. However, the active material of a positive electrode comprises only the first cathode material with ring-shaped pores and not the second cathode material. The specific parameters are listed in Table 1. Comparative example 4

[0194] The battery of Comparative Example 4 is manufactured in a similar manner to the battery of Exemplary Example 32. However, the active material of a positive electrode comprises only the second cathode material with a hollow structure and not the first cathode material. The specific parameters are listed in Table 1. Comparative example 5

[0195] The battery of Comparative Example 5 is manufactured in a similar manner to the battery of Exemplary Example 1. However, the active material of a positive electrode comprises both a first and a second cathode material, both of which have a solid structure. The specific parameters are listed in Table 1. Comparative example 6

[0196] The battery of Comparative Example 6 is manufactured in a similar manner to the battery of Exemplary Example 1. However, the parameters of the manufacturing process for the active material of a positive electrode are adjusted such that the difference between the position of the second peak and the position of the first peak in the particle size distribution diagram of the active material of a positive electrode is 15 µm. The specific parameters are listed in Table 1. Comparative example 7

[0197] The battery of Comparative Example 7 is manufactured in a similar manner to the battery of Exemplary Example 1. However, the parameters of the manufacturing process for the active material of a positive electrode are adjusted such that the difference between the position of the second peak and the position of the first peak in the particle size distribution diagram of the active material of a positive electrode is 2 µm. The specific parameters are listed in Table 1. II. Performance Tests 1. Performance test of the active material of a positive electrode 1) Testing the pore inner diameter

[0198] Conductive adhesive is applied to the sample stage. A powdered sample is taken from each sample of the active material of a positive electrode from the implementation and comparison examples and evenly distributed on the conductive adhesive. Non-adherent powder is blown away with a bellows. A gold layer is then sputtered on, and a cross-section of the powdered sample is prepared using argon plasma. Scanning electron microscopy (SEM) images of the powdered sample are acquired using an instrument such as the ZEISS Sigma 300 at an accelerating voltage of 10 kV and an emission current of 10 mA. The inner diameter of the pores is measured from the SEM images. At least three samples are measured, with at least 50 pores measured from each sample. The arithmetic mean is used as the inner pore diameter of the sample. 2) Examination of the difference between the first and second peak positions

[0199] The particle size distribution is determined by laser diffraction according to GB / T 19077-2016 / ISO 13320:2009 using the Malvern 3000 instrument. A volume-based particle size distribution diagram is created, and the positions of the first and second peaks are determined from this diagram. 3) Porosity testing

[0200] The porosity of the active material of a positive electrode can be tested using all methods known in the industry. As an example, the gas displacement method is used for measurement according to GB / T24586. Porosity = (V1 - V2) / V1 * 100%, where V1 is the apparent volume of the sample and V2 is the actual volume of the sample. 4) Testing the average primary particle size D

[0201] Following imaging with a scanning electron microscope (ZEISS Sigma-02-33, Germany, 500x magnification), 200 to 600 primary particles of the active material from a positive electrode, with complete shape and no overlap, are randomly selected from the electron micrographs. The mean of the largest diameter of the primary particles in the microscopic images is recorded as the average particle size D. 5) Testing of Dv90, Dv50 and Dv10

[0202] According to GB / T 19077-2016, the particle size distribution method using laser diffraction, 0.1 g to 0.13 g of the sample of cathode material / first cathode material / second cathode material to be tested are weighed into a 50 ml beaker, mixed with 5 g of anhydrous ethanol, a magnetic stir bar approximately 2.5 mm long is added, and the beaker is sealed with cling film. The sample is subjected to ultrasonic treatment for 5 minutes and then transferred to a magnetic stirrer, where it is stirred at 500 rpm for more than 20 minutes. Two samples are taken from each product batch for testing. The tests are performed using a Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK.Here, Dv90 is the particle size corresponding to a cumulative volume distribution fraction of 90% of the secondary particles of the first cathode material / second cathode material; Dv50 is the particle size corresponding to a cumulative volume distribution fraction of 50% of the secondary particles of the active material of a positive electrode / first cathode material / second cathode material; and Dv10 is the particle size corresponding to a cumulative volume distribution fraction of 10% of the secondary particles of the first cathode material / second cathode material. 6) Test methods for bulk density

[0203] The bulk density of the active material of a positive electrode is tested in accordance with GB / T 24533-2009 “Determination of the bulk density of metal powders” using a bulk density meter Dandong Baite BT-300.

[0204] Bulk density: The mass per unit volume of a powder in a container after compaction under specified conditions. The calculation formula is as follows: Pt=(m−m0) / V, where: Pt is the bulk density of the powder in g / cm³ 3 ; m the total mass of the measuring cylinder and the sample in g; m0 the mass of the measuring cylinder in g; V is the compressed volume of the powder in cm³ 3 . 2. Performance test of the positive electrode plate1) Compaction density of the positive electrode film layer

[0205] The compaction density of the positive electrode film layer of the positive electrode plate is determined by measuring the areal density (g / cm²). 2The density of the positive electrode film layer is determined by the thickness (cm) of the one-sided positive electrode film layer (number of measuring points > 14). Specifically, the density of the positive electrode film layer corresponds to the areal density of the one-sided positive electrode film layer (g / cm²). 2 ) / Thickness of the positive electrode film layer (cm). 2) Shear strength test

[0206] A piece of double-sided adhesive tape approximately 60 mm long is cut and applied lengthwise to the electrode plate. The electrode plate is then trimmed along the edge of the tape using a knife. A visually flat steel plate is selected, its surface sanded with sandpaper, wiped with a cotton cloth soaked in alcohol, and dried. Double-sided adhesive tape is applied to the steel plate, with a distance of more than 1 cm between the bottom edge of the tape and the bottom edge of the plate. The steel plate is placed in an oven at 60 to 80 °C for 5 minutes, removed, and the release liner is carefully peeled off the tape with a knife. The trimmed electrode plate is then adhered to the tape on the steel plate, test side down. A 2 kg pressure roller is used to roll the plate back and forth three times.The Sansi tensile testing machine is switched on (indicator light illuminates), and the stop is moved into a suitable position. The end of the steel plate without the electrode plate is secured with the lower clamping jaw, and the free end of the electrode plate is gripped with the upper clamping jaw. The test is then performed, and the value is read. The tensile speed is 10 mm / min. 3. Battery performance test1) Testing the volumetric energy density

[0207] Battery cell capacity test: The battery cell is stored for 2 hours at 25°C to ensure a temperature of 25°C. At 25°C, the battery cell is charged at 0.1C up to the final charging voltage of 4.25 V and then charged continuously at this voltage until the current reaches 0.05C, at which point the charging process is terminated (where C denotes the nominal capacity of the battery cell). The battery cell is stored for 1 hour at 25°C. At 25°C, the battery cell is discharged at 0.1C up to the final discharge voltage of 2.5 V. The total discharge capacity C0 and the total discharge energy E0 are recorded.

[0208] Volume measurement of the battery cell: The length, width, and height of the battery cell are measured using calipers. The volume V0 of the battery cell is calculated as the product of its length, width, and height.

[0209] Calculation of the volumetric energy density: The volumetric energy density of the battery cell is: discharge energy of the battery cell E0 / volume of the battery cell V0. 2) Testing the battery discharge time at 40% SOC

[0210] The battery cell is discharged with a constant current of 0.33C to 2.8 V and left to rest for 30 minutes. It is then charged with a constant current of 0.33C to 4.25 V and subsequently with a constant voltage of 0.05C until the voltage stabilizes. It is again left to rest for 30 minutes. Afterward, it is discharged with a constant current of 0.33C to 2.8 V, at which time the initial capacity C0 is recorded. This is followed by a 30-minute rest period. Then, it is charged with a constant current of 0.33C to 4.25 V and subsequently with a constant voltage of 0.05C until the voltage stabilizes. This is followed by a 30-minute rest period. Finally, it is discharged with a constant current of 0.33C to a state of charge of 0.4 C0 Ah (40%) and left to rest for 60 minutes. Finally, it is discharged with a constant current of 4.5C to 2.8V, and the discharge time is recorded. 3) Cycle stability testing

[0211] The secondary batteries produced in the implementation and comparison examples are charged with a constant current of 0.5C to a final charging voltage of 4.25V, then recharged with a constant voltage to a current of ≤ 0.05C, allowed to rest for 5 minutes, and then discharged with a constant current of 0.33C to a final discharge voltage of 2.5V, again allowing to rest for 5 minutes. This constitutes one charge-discharge cycle. Following this method, the battery is subjected to the charge-discharge cycle test until the battery capacity decreases to 80%. The number of cycles at this point corresponds to the battery's cycle life at 25°C. III. Analysis of the test results of the execution and comparison examples

[0212] The batteries used in the implementation and comparison examples are manufactured according to the procedure described above, and the various performance parameters are measured. The results are presented in Tables 1, 2, and 3. Table 1 Serial No. Active material of the positive electrode Positive electrode plate Difference between the positions of the first and second peaks of the active material of the positive electrode / Porosity of the active material of the positive electrode / % Mass ratio of the first cathode material to the second cathode material Bulk density (g / cm³) 2 ) Thickness / µm Example 1 7 0,21 6 2,2 300 Example 2 8 0,2 6 2,1 300 Example 3 10 0,2 6 2,05 300 Example 4 11 0,22 6 1,9 300 Example 5 9 0,19 6 2,14 300 Example 6 6 0,18 6 2,2 300 Example 7 3 0,24 6 2,12 300 Example 8 6 0,18 6 2,12 300 Example 8 5 0,17 6 2,13 300 Example 10 7 0,16 6 2,2 300 Example 11 8 0,18 6 2,4 300 Example 12 6 0,16 6 2,5 300 Example 13 6 0,24 6 1,9 300 Example 14 5 0,22 6 2,25 300 Example 15 8 0,19 6 2,26 300 Example 16 9 0,23 6 2,27 300 Example 17 8 0,24 6 2,28 300 Example 18 7 0,17 6 2,4 300 Example 19 6 0,19 6 2,15 300 Example 20 4 0,16 6 2,36 300 Example 21 6 0,18 6 2,18 300 Example 22 8 0,17 6 2,05 300 Example 23 7 0,16 6 2,1 300 Example 24 7 0,19 6 2,2 300 Example 25 8 0,18 6 2,15 300 Example 26 6 0,21 1,5 2,3 300 Example 27 6 0,2 8 2 300 Example 28 9 0,23 2 2,28 300 Example 29 10 0,22 9 1,96 300 Example 30 9 0,17 6 2,3 200 Example 31 9 0,19 6 2,3 400 Example 32 8 0,16 6 2,16 300 Example 33 8 0,24 6 2,14 300 Example 34 7 0,22 6 2,14 300 Example 35 9 0,21 6 2,13 300 Example 36 8 0,18 6 2,12 300 Example 37 7 0,19 6 2,1 300 Comparative example 1 / 0,21 1,7 300 Comparative example 22 / 0,23 / 1,72 300 Comparative example 3 / 0,24 / 1,71 300 Comparative example 4 / 0,18 / 1,7 300 Comparative example 5 7 0,19 6 2,3 300 Comparative example 6 15 0,16 6 15 300 Comparative example 7 2 0,17 6 2,4 300 Table 2 Serial No. Active material of the positive electrode First cathode material Second cathode material Inner diameter of the hole / µm DV50 / µm (Dv90-Dv50) / Dv50 (Dv50-Dv10) / Dv10 Inner diameter of the hole / µm DV50 / µm (Dv90-Dv50) / Dv50 (Dv50-Dv10) / Dv10 Example 1 Example 2 0,1 12 0,8 2 / 3 1,24 8,5 0,2 12 0,8 2 / 3 1,24 8,5 Example 3 0,4 12 0,8 2 / 3 1,24 8,5 Example 4 Example 5 0,61 1212 0,80,8 22 / / 33 1,241.21 8,58,3 Example 6 3 12 0,8 2 / 3 1,3 9 Example 7 1,2 12 0,8 2 / 3 1,24 8,5 Example 8 Example 9 Example 10 0,80,5 1212 0,80,8 22 / / 33 1,181,18 8,28,2 1 8 0,8 2 / 3 1,3 7,8 Example 11 Example 12 Example 13 1 121018 0,80,80,8 222 / / / 333 1,351,161,4 88,39,5 Example 14 1 12 0,6 2 / 3 1,23 9,8 Example 15 1 17 1,2 2 / 3 1,23 9,8 Example 16 Example 17 Example 18 111 171212 0,80,80,8 1,22,52 / / / 330.8 1,231,231,23 9,89,8 Example 19 1 12 0,8 2 / 4 1,21 9,8 Example 20 Example 21 11 1212 0,80,8 12 / / 15 1,231,23 9,89,8 Example 22 1 12 0,8 2 / 3 1,5 9,8 Example 23 1 12 0,8 2 / 3 0,8 9,8 Example 24 Example 25 Example 26 111 121212 0,80,80,8 222 / / / 333 1,181,181,18 1269,6 Example 27 Example 28 1 12 0,5 2 / 3 1,18 9,6 1 12 0,8 2 / 3 1,18 9,6 Example 29 1 12 0,8 2 ! 3 1,18 9,6 Example 30 Example 31 11 1212 0,80,8 22 / / 33 1,181,18 9,69,6 Example 32 Example 33 Example 34 1 12 0,8 2 l 3 1,18 9,6 10,2 1212 0,80,8 22 0,21 33 1,181,18 9,69,6 Example 35 Example 36 Example 37 Comparative example 1 0,2 12 0,8 2 0,2 3 1,18 9,6 / 12 0,8 2 1 3 1,18 9,6 / 1 1212 0,80,8 22 0,2 / 3 / 1,18 / 9,6 / Comparative example 2 / / / / 0,2 3 1,18 9,6 Comparative example 3 0,2 12 0,8 2 / / / / Comparative example 4 / / / / 1 3 1,18 9,6 Comparative example 5 / 12 0,8 2 / 3 1,18 9,6 Comparative example 6 5 15 0,9 2 / 3 1,15 14 Comparative example 7 0,1 2 0,7 2 / 3 1,14 7,8 Table 3 Serial No. Positive electrode plate battery Compaction density (g / cm³) 2 ) Shear strength / MPa Volumetric energy density (Wh / L) Discharge time / s Cycle stability / cycles Example 1 Example 2 Example 3 3,5 0,9 790 125 1260 3,45 0,85 787 136 1300 3,4 0,8 785 148 1280 Example 4 3,2 0,78 760 152 1100 Example 5 3,3 0,9 846 134 1350 Example 6 Example 7 3,53,32 1,20,91 848765 124133 10001120 Example 8 Example 9 3,253,3 0,730,89 842768 132130 12001160 Example 10 3,4 1 826 134 1280 Example 11 Example 12 3,42 0,9 860 141 1400 3,4 0,85 852 135 1320 Example 13 2,9 0,73 700 150 800 Example 14 3,1 0,9 760 149 880 Example 15 3 0,98 700 151 820 Example 16 2,95 0,86 700 152 798 Example 17 Example 18 Example 19 3,05 0,84 720 150 840 3,153,25 0,860,88 790820 144142 8801000 Example 20 3,44 0,92 850 139 1200 Example 21 Example 22 3,1 0,9 760 151 808 3,05 0,73 700 141 820 Example 23 Example 24 Example 25 3,08 0,75 690 139 830 3,09 0,8 710 131 800 3,11 0,85 715 128 809 Example 26 3,2 0,82 745 115 850 Example 27 3,1 0,53 700 128 880 Example 28 3,22 0,85 750 120 920 Example 29 3,13 0,87 708 124 960 Example 30 Example 31 3,453,15 0,980,73 620790 155118 1300820 Example 32 3,2 0,82 700 131 800 Example of implementation 33 Example of implementation 34 3,19 0,84 750 12 809 3,18 0,78 620 128 880 Example 35 3,19 0,82 790 120 920 Example 36 73,17 0,84 710 124 960 Example 37 3,16 0,99 715 118 820 Comparative example 1 2,8 0,72 600 158 500 Comparative example 2 72,75 0,7 550 155 400 Comparison example 3 Comparison example 4 2,752,7 0,710,11 580500 156153 480380 Comparison example 5 Comparison example 6 3,32,8 0,780,6 690660 90142 460490 Comparative example 7 2,75 0,75 670 121 180

[0213] As can be seen from the table above, the active material of the positive electrode in embodiments 1 to 37 is in the form of secondary particles formed by the aggregation of primary particles, and at least some of the secondary particles have pores; the particle size distribution of the active material of a positive electrode determined by laser diffraction is bimodal, with the difference between the position of the second peak and the position of the first peak being 1 µm to 13 µm.

[0214] As can be seen from the comparison of embodiments 1 to 29 and 32 to 37 with comparative examples 1 to 4, the active material of a positive electrode with a two-peak particle size distribution in this application exhibits higher shear strength compared to an active material of a positive electrode with a single-peak particle size distribution, and the battery has better volumetric energy density and cycle stability. As can be seen from the comparison of embodiments 1 to 29 and 32 to 37 with comparative example 5, it is advantageous to configure at least some of the secondary particles to have pores in order to improve the battery's discharge time and performance.As can be seen from the comparison of embodiments 1 to 29 and 32 to 37 with comparative examples 6 to 7, it is advantageous to limit the difference between the position of the second peak and the position of the first peak to 1 µm to 13 µm in order to improve the compaction density of the positive electrode plate and the cycle stability of the battery.

[0215] As can be seen from embodiments 1 to 4, the secondary particles of the active material of a positive electrode have multiple pores formed by the spaces between the primary particles. The inner diameter of the pores is set to 0.1 µm to 0.6 µm, giving the positive electrode plate excellent shear strength and the battery outstanding volumetric energy density, discharge time, and cycle stability. The inner diameter of the pores is further reduced to 0.2 µm to 0.4 µm to enable even higher cycle stability of the battery.

[0216] As can be seen from embodiments 5 to 9, the secondary particles of the active material of a positive electrode have a single hollow pore surrounded at its center by primary particles. The inner diameter of the pore is set to 0.5 µm to 3 µm, giving the positive electrode plate excellent shear strength and the battery outstanding volumetric energy density, discharge time, and cycle stability. Further control of the pore inner diameter to 0.8 µm to 1.2 µm is advantageous to further improve the discharge time.

[0217] As can be seen from embodiments 5, 10 to 13, the Dv50 of the first cathode material is adjusted to 8 µm to 18 µm, so that the positive electrode plate has excellent shear strength and the battery has excellent volumetric energy density, discharge time, and cycle stability. As can be seen from the comparison of embodiments 5, 11 to 12 with embodiments 10, 13, further control of the Dv50 of the first cathode material to 10 µm to 12 µm takes into account the shear strength of the positive electrode plate, the volumetric energy density, the discharge time, and the cycle stability of the battery.

[0218] As can be seen from embodiments 5 and 14 to 15, the ratio of the difference between Dv90 and Dv50 of the first cathode material to Dv50 of the first cathode material is controlled such that it is between 0.6 and 1.2. This results in the positive electrode plate having excellent shear strength and the battery having excellent volumetric energy density, discharge time and cycle stability.

[0219] As can be seen from embodiments 5, 16 to 17, the ratio of the difference between Dv50 and Dv10 of the first cathode material to Dv10 of the first cathode material is controlled such that it is between 1.2 and 2.5. This results in the positive electrode plate having excellent shear strength and the battery having excellent volumetric energy density, discharge time and cycle stability.

[0220] As can be seen from the comparison of embodiments 5, 18 to 21, controlling the Dv50 of the second cathode material to 0.8 µm to 5 µm results in the positive electrode plate having excellent shear strength and the battery possessing excellent volumetric energy density, discharge time, and cycle stability. As can be seen from the comparison between embodiments 5 and 20 and embodiments 18 to 19 and 21, further controlling the Dv50 of the second cathode material to 1 µm to 3 µm is advantageous to further improve the volumetric energy density and cycle stability of the battery.

[0221] As can be seen from embodiments 5, 22 to 23, the ratio of the difference between Dv90 and Dv50 of the first cathode material to Dv50 of the first cathode material is controlled such that it is between 0.8 and 1.5. This results in the positive electrode plate having excellent shear strength and the battery having excellent volumetric energy density, discharge time and cycle stability.

[0222] As can be seen from embodiments 5, 24 to 25, the ratio of the difference between Dv50 and Dv10 of the first cathode material to Dv10 of the first cathode material is controlled such that conditions 6 to 12 are met, so that the positive electrode plate has excellent shear strength and the battery has excellent volumetric energy density, discharge time and cycle stability.

[0223] As can be seen from embodiments 5, 26 to 29, the mass ratio A of the first cathode material to the second cathode material is adjusted to 1.5 to 9, so that the positive electrode plate has excellent shear strength and the battery has excellent volumetric energy density, discharge time, and cycle stability. As can be seen from the comparison between embodiments 5, 27 to 28 and embodiments 26, 29, by further controlling the mass ratio A of the first cathode material to the second cathode material to 2 to 8, the shear strength of the positive electrode plate, the volumetric energy density of the battery, the discharge time, and the cycle stability can be taken into account.

[0224] As can be seen from embodiments 5, 30 to 31, the thickness of the positive electrode film layer is set to 200 µm to 400 µm, so that the positive electrode plate has excellent shear strength and the battery has excellent volumetric energy density, discharge time and cycle stability.

[0225] It should be noted that the present application is not limited to the embodiments described above. The embodiments described above serve only as examples. All embodiments that, within the scope of the technical concept of this application, have essentially the same structure and achieve the same effect are covered by the scope of protection of this application. Furthermore, without deviating from the essence of this application, various modifications of the embodiments that are obvious to a person skilled in the art, as well as other configurations formed by combining parts of the embodiments, are also included in the scope of protection of this application. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 202310473126

[0001] Cited non-patent literature

[0000] GB / T 19077-2016 [0067, 0086, 0202] GB / T 19587-2017 “Determination of the specific surface area of ​​solids by gas adsorption using the BET method

[0089] GB / T24586

[0200] GB / T 24533-2009 “Determination of the bulk density of metal powders

[0203]

Claims

Active material of a positive electrode, characterized in that the active material of a positive electrode is in the form of secondary particles formed by aggregation of primary particles, and that at least some of the secondary particles have pores; and the particle size distribution of the active material of a positive electrode determined by laser diffraction is bimodal and the difference between the position of the second peak and the position of the first peak is 1 µm to 13 µm. Active material of a positive electrode according to claim 1, characterized in that the position of the first peak is at 1 µm to 5 µm, optionally at 1.5 µm to 4.5 µm; and / or the position of the second peak is at 6 µm to 14 µm, optionally at 8 µm to 12 µm. Active material of a positive electrode according to claim 1 or 2, characterized in that the inner diameter of the pores is 0.1 µm to 3 µm. Active material of a positive electrode according to claim 1 or 2, characterized in that the secondary particles comprise several pores formed by the spaces between the primary particles, wherein the inner diameter of the pores is 0.1 µm to 0.6 µm, optionally 0.2 µm to 0.4 µm; or the secondary particles comprise a single hollow pore in a central position enclosed by primary particles, wherein the inner diameter of the pore is 0.5 µm to 3 µm, optionally 0.8 µm to 1.2 µm. Active material of a positive electrode according to claim 1 or 2, characterized in that the secondary particles further comprise pores located inside the primary particles, wherein the inner diameter of the pores is 0.01 µm to 0.06 µm. Active material of a positive electrode according to one of claims 1 to 5, characterized in that the active material of a positive electrode has the following chemical formula: LiaNixM1yM21-x-yO2, wherein M1 and M2 comprise one or more of the elements Co, Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg and Nb with 0.8≤a≤1.2, 0.55≤x≤1.0 and 0≤y≤0.45 and optionally 0.8≤a≤1.2, 0.95≤x≤0.995 and 0≤y≤0.

05. Active material of a positive electrode according to one of claims 1 to 6, characterized in that the average particle size D of the primary particles of the active material of a positive electrode is 0.1 µm to 0.8 µm, optionally 0.2 µm to 0.5 µm. Active material of a positive electrode according to one of claims 1 to 7, characterized in that the Dv50 of the secondary particles of the active material of a positive electrode is 9 µm to 15 µm, optionally 10 µm to 12 µm. Active material of a positive electrode according to one of claims 1 to 8, characterized in that the specific surface area of ​​the active material of a positive electrode is 0.1 m2 / g to 1.0 m2 / g, optionally 0.2 m2 / g to 0.5 m2 / g. Active material of a positive electrode according to one of claims 1 to 9, characterized in that the active material of a positive electrode comprises a first cathode material and a second cathode material. Active material of a positive electrode according to claim 10, characterized in that the first cathode material has pores and the second cathode material has a solid structure; or the first cathode material has a solid structure and the second cathode material has pores; or both the first and the second cathode material have pores. Active material of a positive electrode according to claim 10 or 11, characterized in that the mass ratio A of the first cathode material to the second cathode material and the porosity B of the active material of a positive electrode satisfy the following relationship: 0 ≤ |B - A×0.4 - (1-A)×0.2| ≤ 1. Active material of a positive electrode according to one of claims 10 to 11, characterized in that the mass ratio A of the first cathode material to the second cathode material is 1.5 to 9, optionally 2 to 8. Active material of a positive electrode according to one of claims 1 to 13, characterized in that the porosity B of the active material of a positive electrode is 0.15% to 0.45%, optionally 0.25% to 0.35%. Active material of a positive electrode according to one of claims 10 to 14, characterized in that the first cathode material and the second cathode material each independently have the following chemical formula: LiaNixM1yM21-x-yO2, wherein M1 and M2 comprise one or more of the elements Co, Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg and Nb with 0.8≤a≤1.2, 0.55≤x≤1.0 and 0≤y≤0.45 and optionally 0.8≤a≤1.2, 0.95≤x≤0.995 and 0≤y≤0.

05. Active material of a positive electrode according to one of claims 10 to 15, characterized in that the Dv50 of the first cathode material is 8 µm to 18 µm, optionally 10 µm to 12 µm. Active material of a positive electrode according to one of claims 10 to 16, characterized in that the Dv50 of the second cathode material is 0.8 µm to 5 µm, optionally 1 µm to 3 µm. Active material of a positive electrode according to one of claims 10 to 17, characterized in that the ratio of the difference between Dv90 and Dv50 of the first cathode material to Dv50 of the first cathode material is 0.6 to 1.2, optionally 0.8 to 1.0; and / or the ratio of the difference between Dv50 and Dv10 of the first cathode material to Dv10 of the first cathode material is 1.2 to 2.5, optionally 1.5 to 2.

0. Active material of a positive electrode according to one of claims 10 to 18, characterized in that the ratio of the difference between Dv90 and Dv50 of the second cathode material to Dv50 of the second cathode material is 0.8 to 1.5, optionally 1.0 to 1.3; and / or the ratio of the difference between Dv50 and Dv10 of the second cathode material to Dv10 of the second cathode material is 6 to 12, optionally 8 to 10. Positive electrode plate, characterized in that the positive electrode plate comprises a positive current collector and a positive electrode film layer arranged on at least one surface of the positive current collector, wherein the positive electrode film layer comprises an active material of a positive electrode according to one of claims 1 to 19. Positive electrode plate according to claim 20, characterized in that the thickness of the positive electrode film layer is 200 µm to 400 µm, optionally 220 µm to 300 µm. Positive electrode plate according to claim 20 or 21, characterized in that the compaction density of the positive electrode film layer is 2.9 g / m2 to 3.5 g / m2. Secondary battery, characterized in that it comprises a positive electrode plate according to one of claims 20 to 21. Electrical device characterized in that it comprises a secondary battery according to claim 23.

Images