Cathode material precursor, its manufacturing method, and applications

Abstract

This application discloses a cathode material precursor, a method for producing the same, and its applications, relating to the technical field of cathode materials for lithium-ion batteries. The cathode material precursor of this application comprises precursor particles, which are formed by the aggregation of a plurality of first particles, each first particle having a core-shell structure, the core-shell structure having a core and a surface layer, the core having a dense seed crystal, and the surface layer having a plurality of whiskers with voids between adjacent whiskers. This forms a large particle precursor that is highly aggregated, porous, and has a sparse, puff-like surface morphology, which is advantageous for industrial production.

Description

Cross-reference of related applications

[0001] This application requests priority from the Chinese patent application filed with the Chinese National Intellectual Property Office on December 29, 2023, with application number 202311871460.7, and the title of the invention "Cathode Material Precursor, Method for Manufacturing the Same, and Applications," the entire contents of which are incorporated into this application by reference. [Technical Field]

[0002] This application relates to the field of battery materials technology, and more specifically, to positive electrode material precursors, methods for producing the same, and applications. [Background technology]

[0003] With the increase in sales of new energy vehicles and the steady growth of markets such as power tools, the application of ternary cathode materials is growing rapidly, and the performance of ternary cathode materials (e.g., lithium nickel-cobalt-manganate) largely depends on the performance of the ternary precursor (e.g., nickel-cobalt-manganese hydroxide). Currently, one of the main development trends for ternary cathode materials is single crystallization. By adopting single-crystal materials, it is possible to reduce grain boundaries, decrease the occurrence of side reactions, improve compressive density, increase energy density, and extend the battery cycle life.

[0004] However, the manufacturing process for single-crystal materials is complex. Compared to the manufacturing of polycrystalline materials, single-crystal materials require higher sintering temperatures, which tend to cause mixed emission of nickel-lithium at high temperatures. Simultaneously, during the sintering process, primary particles grow and secondary particles adhere, requiring polishing after sintering. If sintering is insufficient, a quasi-single crystal is formed, and the material fails to achieve the expected effect. Furthermore, current single-crystal materials are mainly obtained by sintering small particle precursors. However, conventional small particle precursors tend to cause multi-stage aggregation and poor particle uniformity during the reaction. The sintering temperature required is high, sintering is often insufficient, and sintering is difficult. Moreover, mixed emission of nickel-lithium is likely to occur at high temperatures, and the performance of the cathode material fails to achieve the desired effect.

[0005] Therefore, in order to solve the above problems, it is necessary to provide a cathode material precursor, a method for producing the same, and its applications. [Overview of the Initiative]

[0006] One of the objectives of the embodiments of this invention is to provide a cathode material precursor, a method for producing the same, and its applications. The invention aims to produce a large particle precursor that is highly aggregated, porous, and has a sparse, puff-like surface morphology. The large particle precursor is formed by the aggregation and growth of small particles, and the surface layer of the small particles has many voids. During the sintering process, lithium elements enter the interior of the particles, making sintering more complete, reducing the formation of quasi-single crystal particles, and lowering the difficulty of sintering the precursor. Furthermore, dense seed crystals exist inside the small particles, making them relatively easy to crush after sintering, and resulting in relatively more uniform crushing.

[0007] The technical solutions used in the embodiments of this application are as follows:

[0008] According to the first aspect, a positive electrode material precursor is provided, the positive electrode material precursor comprises precursor particles, the precursor particles are formed by the aggregation of a plurality of first particles, and the first particles have a core-shell structure having a core and a surface layer. The core has a dense seed crystal, The surface layer has a plurality of whiskers, with gaps between adjacent whiskers.

[0009] In some embodiments, the ratio of the seed crystal particle size to the particle size of the first particle is in the range of 30%-40%.

[0010] In some embodiments, the ratio of the particle size of the first particle to the particle size of the precursor particle is in the range of 20%-50%.

[0011] In some embodiments, the thickness range of the whiskers is 10 nm to 30 nm.

[0012] In some embodiments, the specific surface area range of the precursor particles is 20 m². 2 / g-40m 2 It is / g.

[0013] In some embodiments, each precursor particle further comprises a shell layer that covers the surface layer of the core-shell structure.

[0014] In some embodiments, the thickness of the shell layer is in the range of 0.2 μm to 0.5 μm.

[0015] In some embodiments, the core thickness of the core-shell structure ranges from 4 μm to 8 μm.

[0016] A second aspect of the present application provides a method for manufacturing a positive electrode material precursor, which is manufactured from the following steps: A mixed metal ion solution is obtained by mixing multiple metal ion sources with water, and a first alkaline solution and a complexing agent are prepared separately. After adding water to the reactor and introducing a protective gas, the first alkaline solution and the complexing agent are added to form the reaction bottom liquid. The first alkaline solution, the complexing agent, and the mixed metal ion solution are added to the reactor in parallel to carry out a nucleation reaction, the reaction atmosphere is controlled to a first atmosphere to form seed crystals, and when it is detected that the seed crystal content has reached the target, the pH of the reaction solution is lowered and the reaction atmosphere is controlled to a second atmosphere to maintain the growth reaction of seed crystal granules. The system continuously supplies the material, performs filtration after detecting that the liquid level in the reactor has reached the filtration requirement, maintains a stable liquid level in the reactor, and stops supplying the material and discharges it into the container when it is detected that the particle size of the material in the reactor has reached the target. The material in the container is subjected to solid-liquid separation, and the separated filtered cake is processed to obtain the cathode material precursor.

[0017] In some embodiments, the first atmosphere includes at least the protective gas, and the second atmosphere includes air and the protective gas.

[0018] In some embodiments, in the second atmosphere, the air flow rate gradually increases as the solid content of the material increases.

[0019] In some embodiments, the air flow rate range of the first atmosphere is 0 L / h - 800 L / h, and the protective gas flow rate range of the first atmosphere is 100 L / h - 800 L / h.

[0020] In some embodiments, the air flow rate range of the second atmosphere is 300 L / h - 800 L / h, and the protective gas flow rate range of the second atmosphere is 0 L / h - 300 L / h.

[0021] In some embodiments, the concentration range of the complexing agent for the nucleation reaction is 2.0 g / L - 10.0 g / L.

[0022] In some embodiments, the concentration range of the complexing agent for the growth reaction is 1.0 g / L - 10.0 g / L.

[0023] In some embodiments, the flow rate range of the mixed metal ion solution is 0.5 L / h - 40 L / h.

[0024] In some embodiments, the flow rate ratio range of the first alkali solution, the complexing agent, and the mixed metal ion solution is 0 - 9:3 - 20:20 - 133.

[0025] In some embodiments, the pH range of the reaction solution is 10.0 - 11.5.

[0026] The third aspect of the present application provides a positive electrode material including the above positive electrode material precursor.

[0027] The fourth aspect of the present application provides a secondary battery including a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte solution, wherein the positive electrode sheet includes the above positive electrode material.

[0028] The cathode material precursor according to this application is formed by the aggregation and growth of small particles, and the surface of the small particles has many voids, which is advantageous for lithium elements to enter the interior of the particles during the sintering process and make sintering more complete. This reduces the generation of quasi-single crystal particles and lowers the difficulty of sintering the precursor. At the same time, dense seed crystals are present inside the small particles, making them relatively easy to crush after sintering, and the crushing becomes relatively more uniform. As a result, a large-particle cathode material precursor with high aggregation, porousness, and a sparse, puff-like surface morphology can be obtained, and this cathode material precursor has features such as an ultra-large specific surface area, a large internal porosity, and a low tap density. [Brief explanation of the drawing]

[0029] To more clearly explain the technical concepts in the embodiments of the present application, the drawings that may be used to describe the embodiments or exemplary techniques are briefly described below. Clearly, the drawings in the following description are only a few embodiments of the present application, and those skilled in the art can obtain other drawings based on these without any creative work.

[0030] Figure 1 is a flow diagram of the manufacturing process for a cathode material precursor according to an embodiment of the present invention.

[0031] Figure 2 is a schematic diagram of the structure of the main reaction vessel, concentrator, filter rod, filtration pump, and filter according to an embodiment of the present invention.

[0032] Figures 3-8 are electron microscope images of the cathode material precursor according to Example 1 of the present application at different magnifications.

[0033] Figures 9-14 are electron microscope images of the cathode material precursor according to Example 2 of the present application at different magnifications.

[0034] Figures 15-20 are electron microscope images of the cathode material precursor according to Example 3 of the present application at different magnifications.

[0035] Figures 21-26 are electron microscope images of the cathode material precursor according to Comparative Example 1 of the present application at different magnification levels.

[0036] Figures 27-32 are electron microscope images of the cathode material precursor according to Comparative Example 2 of the present application at different magnification levels.

[0037] Figures 33-38 are electron microscope images of the cathode material precursor according to Comparative Example 3 of the present application at different magnification levels. [Modes for carrying out the invention]

[0038] To further clarify the purpose, technical solutions, and advantages of this application, the application will be described in more detail below with reference to the drawings and embodiments. The specific embodiments described herein are for interpretation purposes only and do not limit the application.

[0039] In this application, the terms "and / or" describe the relationship between related objects and indicate that three relationships may exist. For example, A and / or B may indicate that A exists alone, A and B exist simultaneously, or B exists alone. However, A and B may be singular or plural. The letter " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0040] In this application, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or similar expressions means any combination of these terms, including any combination of a single term or multiple terms. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can each represent a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be one or more.

[0041] In the various embodiments of this application, the magnitude of the process numbers does not indicate the order of execution, and some or all of the steps may be executed in parallel or sequentially. It should be understood that the execution order of each process should be determined by its function and internal logic, without limiting the implementation processes of the embodiments of this application.

[0042] The terms used in the embodiments of this application are for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms “one type,” “the said,” and “the said” used in the embodiments of this application and in the appended claims are also intended to include the plural form unless the preceding or following text clearly indicates otherwise.

[0043] The terms "first," "second," etc., are merely for the purpose of describing the purpose and distinguishing between different substances or other purposes, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features shown. For example, within the scope of the embodiments of this application, the first XX may be called the second XX, and similarly, the second XX may be called the first XX. Therefore, features limited to "first," "second," etc., may explicitly or implicitly include one or more such features.

[0044] To illustrate the technical solution described in this application, a detailed explanation follows with reference to specific drawings and examples.

[0045] In a first embodiment, the embodiment of the present application provides a cathode material precursor comprising precursor particles formed by the aggregation of a plurality of first particles having a core-shell structure, wherein the core-shell structure has a core and a surface layer, the core has a dense seed crystal, and the surface layer has a plurality of whiskers with voids between adjacent whiskers.

[0046] The embodiments of this invention provide a cathode material precursor in which the precursor particles are formed by the aggregation and growth of small particles, and the surface of the small particles has many voids, allowing lithium elements to enter the interior of the particles during the sintering process, making sintering more complete, reducing the formation of quasi-single crystal particles, lowering the difficulty of sintering the precursor, and the presence of dense seed crystals inside the small particles, making them relatively easy to crush after sintering, and the crushing becomes relatively more uniform. As a result, a large-particle cathode material precursor exhibiting high aggregation, porousness, and a sparse, puff-like surface morphology can be obtained, and this cathode material precursor has characteristics such as an ultra-large specific surface area, a large internal porosity, and a low tap density, thereby enabling the acquisition of a single-crystal material with a relatively high compressibility density, improving energy density and further extending the battery cycle life.

[0047] The cathode material precursor in the embodiments of this application is applicable to products such as binary cathode material precursors and ternary cathode material precursors.

[0048] In some embodiments, the ratio of the seed crystal particle size to the particle size of the first particle ranges from 30% to 40%. The ratio of the seed crystal particle size to the particle size of the first particle is not particularly limited and may be, for example, 30%, 35%, or 40%.

[0049] In some examples, the ratio of the particle size of the aggregated first particles to the particle size of the precursor particles ranges from 20% to 50%. The ratio of the particle size of the aggregated first particles to the particle size of the precursor particles is not particularly limited and may be, for example, 20%, 40%, or 50%.

[0050] In some embodiments, the precursor particles of the embodiments of the present invention are formed by the aggregation and growth of small particles, and relatively dense seed crystals exist inside the aggregated small particles, making them relatively easy to crush after sintering, and the crushing is relatively uniform.

[0051] In some examples, the general molecular formula of the cathode material precursor is Ni x Co y Mnz It may be (OH)₂, where x + y + z = 1, and 0.6 ≤ x ≤ 1.0, 0 < y ≤ 0.20, 0 < z ≤ 0.40.

[0052] In some embodiments, the thickness range of the core of the core-shell structure may include 4 μm - 8 μm. Exemplarily, the core of the core-shell structure may be 4 μm, 5 μm, 6 μm, 7 μm, or 8 μm, etc.

[0053] In some embodiments, there are many voids on the surface layer of the small particles in the embodiments of the present application. During the sintering process, lithium elements enter the particles, making the sintering more sufficient, reducing the generation of quasi-single crystal particles, and being advantageous for reducing the sintering difficulty of the precursor.

[0054] In some embodiments, the thickness range of the whiskers includes 10 nm - 30 nm. The thickness of the above whiskers is not particularly limited, and may be, for example, 10 nm, 20 nm, or 30 nm, etc.

[0055] In some embodiments, the specific surface area range of the precursor particles is 20 m 2 / g - 40 m 2 / g. The specific surface area of the above precursor particles is not particularly limited. Exemplarily, the specific surface area of the precursor particles may be 20 m 2 / g, 30 m 2 / g, or 40 m 2 / g, etc.

[0056] The embodiments of the present application provide a cathode material precursor. The whiskers on the surface layer of the small particles of the cathode material precursor are thin, the morphology is porous puff-like, the whiskers are thin, and the specific surface area is large. Therefore, the strength of the particles is reduced, the sintering difficulty is reduced, and thus the sintering can be made more sufficient. And because the strength of the particles is reduced, the crushing difficulty after sintering is reduced, and the particles are easily crushed.

[0057] In some embodiments, the precursor particles further include a shell layer covering the surface of the core-shell structure, with the shell layer thickness ranging from 0.2 μm to 0.5 μm. The thickness of the shell layer is not particularly limited, and for example, the shell layer thickness may be 0.2 μm, 0.3 μm, or 0.5 μm.

[0058] In some embodiments, the core thickness of the core-shell structure is in the range of 4 μm to 8 μm. For example, the core thickness may be 4 μm, 5 μm, 6 μm, 7 μm, or 9 μm.

[0059] The embodiments of this application provide a cathode material precursor, and the shell layer outside the surface layer can provide strength to the surface of the large particles of the precursor, thereby avoiding particle fragmentation due to equipment issues during processes such as washing and drying of cathode material precursor particles, and improving the success rate of manufacturing cathode material precursor particles. Furthermore, because the shell layer is thin, it has little impact on the sintering and performance of the normal material.

[0060] In a second embodiment, the embodiments of the present application provide a method for producing a cathode material precursor, comprising the following steps: A mixed metal ion solution is obtained by mixing multiple metal ion sources with water, and a first alkaline solution and a complexing agent are prepared separately. After adding water to the reactor and introducing a protective gas, the first alkaline solution and the complexing agent are added to form the reaction bottom liquid. The first alkaline solution, the complexing agent, and the mixed metal ion solution are added to the reactor in parallel to carry out a nucleation reaction, and the reaction atmosphere is controlled to a first atmosphere to form seed crystals. When it is detected that the seed crystal content has reached the target, the pH value of the reaction solution is lowered and the reaction atmosphere is controlled to a second atmosphere to maintain the growth reaction of seed crystal granules. The system continuously supplies the material, performs filtration after detecting that the liquid level in the reactor has reached the filtration requirement, maintains a stable liquid level in the reactor, and stops supplying the material when it is detected that the particle size of the material in the reactor has reached the target, and discharges the material into the container. The material in the container is subjected to solid-liquid separation, and the separated filtered cake is processed to obtain the cathode material precursor.

[0061] The embodiments of this application provide a method for producing a cathode material precursor, and by employing a batch process, the amount of nitrogen gas and air introduced in the growth reaction stage is controlled, and in combination with the stirring rotation speed in the reaction process, a large particle cathode material precursor that is highly aggregated, porous, and has a sparse, puff-like surface morphology is formed.

[0062] In some embodiments, the cathode material precursor is a ternary cathode precursor material, and the manufacturing method includes the following specific steps.

[0063] In step 1, according to the molar ratios of nickel (Ni), cobalt (Co), and manganese (Mn) elements required for the cathode material precursor, Ni-soluble salts, Co-soluble salts, and Mn-soluble salts are selected in molar ratios, then mixed with pure water to prepare a mixed metal ion solution having a first concentration, and a first alkaline solution having a second concentration and a complexing agent having a third concentration are prepared, respectively.

[0064] In some examples, the mixed metal ion solution includes, but is not limited to, solutions formed from Ni-soluble salts, Co-soluble salts, and Mn-soluble salts, and may be of alkaline origin or other sources, depending on the specific application.

[0065] In some embodiments, the molar ratio range of the Ni-soluble salt, Co-soluble salt, and Mn-soluble salt in step 1 above may include (88-96):(2-8):(2-8). Exemplarily, the molar ratios of the Ni-soluble salt, Co-soluble salt, and Mn-soluble salt may be 88:6:6, 88:4:8, 96:2:2, etc.

[0066] In some embodiments, the pure water in step 1 above may be deionized water. In some embodiments, the deionized water may be hot water.

[0067] In some embodiments, the range of the first concentration value in step 1 above may include 1.2–2.7 mol / L. For example, the first concentration may be 1.2 mol / L, 1.8 mol / L, 2.3 mol / L, or 2.7 mol / L.

[0068] In some embodiments, the first alkaline solution in step 1 is not particularly limited, and exemplary, the first alkaline solution may be a sodium hydroxide (NaOH) solution or the like.

[0069] In some embodiments, the range of the second concentration of the first alkaline solution in step 1 above may include 1.0–13.0 mol / L. For example, the second concentration may be 1.0 mol / L, 3.0 mol / L, 10.5 mol / L, or 13.0 mol / L.

[0070] In some embodiments, the complexing agent in step 1 is not particularly limited, and exemplary the complexing agent may be aqueous ammonia (NH3·H2O) or the like.

[0071] In some examples, the range of the third concentration of the complexing agent in step 1 above may include 1.0–12.0 mol / L. For example, the third concentration may be 1.0 mol / L, 3.0 mol / L, 6.0 mol / L, or 12 mol / L.

[0072] The order in which the mixed metal ion solution having a first concentration, the first alkaline solution having a second concentration, and the complexing agent having a third concentration are prepared in Step 1 is not particularly limited. For example, the mixed metal ion solution having a first concentration may be prepared first, followed by the first alkaline solution having a second concentration and the complexing agent having a third concentration. Alternatively, the first alkaline solution having a second concentration and the complexing agent having a third concentration may be prepared first, followed by the mixed metal ion solution having a first concentration. Alternatively, the mixed metal ion solution having a first concentration, the first alkaline solution having a second concentration, and the complexing agent having a third concentration may be prepared simultaneously.

[0073] In step 2, water is supplied to and returned to the reactor. Specifically, water is added to the reactor and a protective gas is introduced, after which the first alkaline solution and the complexing agent are added to form the reaction bottom liquid.

[0074] In some embodiments, the type of reactor in step 2 is not particularly limited, and the reactor may be a reaction vessel or the like, for example.

[0075] In some embodiments, step 2 above may include opening the jacket of the reactor and supplying and returning water.

[0076] In some embodiments, pure water in a first amount is added to the reactor, a protective gas is introduced, and then the first alkaline solution and complexing agent are added at a first temperature and a first stirring speed to form a reaction bottom.

[0077] In some embodiments, the range of the first amount of pure water used may include 40-200 L. In some embodiments, the range of the first amount used may include 50-160 L, and exemplary, the first amount used may be 50 L, 100 L, or 160 L.

[0078] In some embodiments, the protective gas is not particularly limited and may include, for example, nitrogen gas (N2). The following embodiments will all be described assuming that the protective gas is N2.

[0079] In some examples, the pH range of the reaction broth may include 11.0-12.5 (45°C). In some examples, the pH range of the reaction broth may include 11.5-12.3 (45°C), and exemplary, the pH of the reaction broth may be 11.5 (45°C), 12.0 (45°C), or 12.3 (45°C).

[0080] In some examples, the above range of complexing agent concentration values ​​may include 2.0 g / L to 10.0 g / L. In some examples, the range of complexing agent concentration values ​​may include 4.0 to 9.0 g / L, and exemplary complexing agent concentrations may be 4.0 g / L, 6.0 g / L, or 9.0 g / L, etc.

[0081] In some embodiments, the range of the first temperature values ​​described above may include 50-70°C. For example, the first temperature may be 50°C, 60°C, or 70°C.

[0082] In some embodiments, the range of the first stirring speed values ​​described above may include 400-600 rpm. For example, the first stirring speed may be 400 rpm, 500 rpm, or 600 rpm.

[0083] In step 3, the first alkaline solution, complexing agent, and mixed metal ion solution are added to the reactor in parallel at a first flow rate ratio at a second stirring speed to carry out a nucleation reaction. The reaction temperature is controlled to a first temperature, the reaction atmosphere to a first atmosphere, the pH of the reaction solution to a first pH value, and the concentration of the complexing agent to a fourth concentration to form seed crystals. When it is detected that the seed crystal content has reached the target, the first pH value is lowered, the reaction temperature is controlled to a second temperature, the reaction atmosphere to a second atmosphere, the pH of the reaction solution to a second pH value, and the concentration of the complexing agent to a fifth concentration to maintain the growth reaction of seed crystal granules in the reactor.

[0084] In some embodiments, the first atmosphere in step 3 above includes at least a protective gas, and the second atmosphere includes a protective gas and air.

[0085] In some examples, the range of the amount of mixed metal ion solution added in step 3 above may include 0.5 L / h to 40 L / h. In some examples, the range of the amount of mixed metal ion solution added includes 1 to 30 L / h, and exemplary amounts of the mixed metal ion solution added may be 1 L / h, 10 L / h, 20 L / h, or 30 L / h.

[0086] In some embodiments, the range of values ​​for the second stirring speed in step 3 above may include 50-600 rpm. In some embodiments, the range of values ​​for the second stirring speed may include 100-550 rpm, and exemplary the second stirring may be 100 rpm, 200 rpm, 300 rpm, 400 rpm, or 550 rpm, etc.

[0087] In some embodiments, the range of the first temperature value in step 3 above may include 40.0–75.0°C. In some embodiments, the range of the first temperature value may include 45.0–65.0°C, and exemplary the first temperature may be 45.0°C, 55.0°C, or 65.0°C, etc.

[0088] In some embodiments, the pH range of the reaction solution for the nucleation reaction in step 3 above may include 11.0-12.5 (45°C). In some embodiments, the pH range of the reaction solution for the nucleation reaction may include 11.5-12.3 (45°C), and exemplary, the pH value of the reaction solution for the nucleation reaction may be 11.5 (45°C), 12.0 (45°C), or 12.3 (45°C), etc.

[0089] In some examples, the range of the complexing agent concentration in step 3 above may include 2.0 g / L to 10.0 g / L. In some examples, the range of the complexing agent concentration in the nucleation reaction includes 4.0 to 9.0 g / L, and exemplary, the complexing agent concentration in the nucleation reaction may be 4.0 g / L, 6.0 g / L, 7.0 g / L, or 9.0 g / L, etc.

[0090] In some embodiments, the first atmosphere in step 3 is not particularly limited and, exemplary, may include N2, or may include N2 and air, where air mainly refers to oxygen (O2).

[0091] In some embodiments, the range of the nitrogen gas flow rate in the first atmospheric liquid in step 3 above may include 100 L / h to 800 L / h. In some embodiments, the range of the nitrogen gas flow rate in the first atmospheric liquid includes 150 to 700 L / h, and exemplary the nitrogen gas flow rate in the first atmospheric liquid may be 150 L / h, 300 L / h, 600 L / h, or 700 L / h.

[0092] In some embodiments, the range of values ​​for the air flow rate in the first atmospheric liquid in step 3 above may include 0 L / h to 800 L / h. In some embodiments, the range of values ​​for the air flow rate in the first atmospheric liquid may include 0 to 700 L / h, and exemplary, the air flow rate in the first atmospheric liquid may be 0 L / h, 300 L / h, 600 L / h, or 700 L / h.

[0093] In some embodiments, the pH range of the reaction solution in step 3 above may include 10.0-11.5 (45°C). In some embodiments, the pH range of the reaction solution in the growth reaction may include 10.2-11.3 (45°C), and exemplary, the pH of the reaction solution in the growth reaction may be 10.2 (45°C), 11.0 (45°C), or 11.3 (45°C), etc.

[0094] In some examples, the range of the complexing agent concentration in step 3 above may include 1.0 g / L to 10.0 g / L. In some examples, the range of the complexing agent concentration in the growth reaction may include 3.0 to 9.0 g / L, and exemplary, the complexing agent concentration in the growth reaction may be 3.0 g / L, 5.0 g / L, 8.0 g / L, or 9.0 g / L.

[0095] In some embodiments, the range of the nitrogen gas flow rate in the second atmospheric solution for the growth reaction in step 3 above may include 0 L / h to 300 L / h. In some embodiments, the range of the nitrogen gas flow rate in the second atmospheric solution may include 0 to 250 L / h, and exemplary, the nitrogen gas flow rate in the second atmospheric solution may be 0 L / h, 50 L / h, 100 L / h, or 250 L / h.

[0096] In some embodiments, the range of values ​​for the air flow rate in the second atmospheric liquid in step 3 above may include 300 L / h to 800 L / h. In some embodiments, the range of values ​​for the air flow rate in the second atmospheric liquid may include 350 to 750 L / h, and exemplary, the air flow rate in the second atmospheric liquid may be 350 L / h, 500 L / h, 600 L / h, or 750 L / h, etc.

[0097] In some examples, step 3 allows for the thinning of the surface whiskers of the particles and improvement of particle porosity by controlling the amount of N2 and air introduced through a batch process to adjust the ratio of the oxidizing agent (air). Thus, the amount of oxidation can be increased with increasing synthesis time, the porosity inside the particles becomes uniform, and the morphology becomes porous and puff-like. Furthermore, because the surface whiskers are thin, the strength of the particles is reduced, and the stirring speed can be reduced according to the particle size during the reaction process to avoid particle crushing due to stirring. In addition, the reaction pH value, temperature, metal liquid flow rate, alkali flow rate, and complexing agent flow rate can be kept stable during the synthesis process.

[0098] In some embodiments, during the growth reaction step in step 3, the airflow rate in the second atmosphere within the reaction vessel gradually increases with increasing solid content in the system. This allows for better seed crystal growth by controlling the nitrogen and oxygen content during the growth reaction step.

[0099] In step 4, the material is supplied in accordance with step 3, and after detecting that the liquid level in the reactor has reached the filtration requirement, the filter is activated and filtration is started, the liquid level in the reactor is kept stable, and when it is detected that the particle size of the material in the reactor has reached the target, the supply to the reactor is stopped, the material is stirred and matured for a first time, and then supplied to the container.

[0100] In some embodiments, the type of filter is not particularly limited, and the filter may, for example, be a concentrator or the like.

[0101] In some embodiments, the type of container is not particularly limited, and the container may, for example, be a pass slurry tank, a relay tank, or the like.

[0102] In some embodiments, the range of material particle size values ​​in the reactor in step 4 above may include 10-20 μm. For example, the material particle size may be 10 μm, 15 μm, or 20 μm.

[0103] In some embodiments, the range of the first time value may include 1-2h, and exemplary, the first time may be 1h, 1.5h, or 2h.

[0104] In some embodiments, step 4 may include the following steps: continuing to supply according to step 3, activating the filter to start filtration after detecting that the liquid level in the reactor has reached the filtration requirement, maintaining a stable liquid level in the reactor, stopping the supply to the reactor when it is detected that the particle size of the material in the reactor has reached the target, continuing to stir for a first time to allow it to mature, and then discharging the material into the container.

[0105] In step 41, the material is supplied in accordance with step 3, and after it is detected that the liquid level in the reactor has reached the filtration requirement, the filter is activated and filtration is started, maintaining a stable liquid level in the reactor, and air is introduced. When it is detected that the particle size of the material in the reactor has reached the target, the supply to the reactor is stopped, the material is stirred and matured for a first time, and then the material is discharged into the container.

[0106] This allows for the formation of a shell layer of a certain thickness on the cathode material precursor by introducing air into the reactor before detecting that the particle size of the material in the reactor has reached the target, thereby improving the surface strength of the cathode material precursor, avoiding particle crushing by equipment during steps such as washing and drying the cathode material precursor, and improving the success rate of cathode material precursor production.

[0107] In step 5, the material in the container is separated into solid and liquid components, the separated filter cake is washed with a second alkaline solution, and then washed with pure water to obtain a washed filter cake.

[0108] In some examples, the second alkaline solution in step 5 is not particularly limited and may, for example, be a NaOH solution, a potassium hydroxide (KOH) solution, or the like.

[0109] In some embodiments, the washed filter cake is dried, followed by sieving and demagnetization to obtain a cathode material precursor.

[0110] In the production of polycrystalline materials in related technologies, mixing large and small particles is sometimes considered. However, to avoid problems such as not being able to determine whether the large particles are uniform after steps such as sintering and crushing, small particles are often used in the production of single-crystal materials. In the embodiment of the present application, small particles with a core-shell structure aggregate to form a large particle precursor during precursor production, lithium ions penetrate the precursor particles more sufficiently during the sintering process, and sintering is more complete. Furthermore, during crushing, the large particle precursor is more easily crushed into multiple small particles, reducing the difficulty of sintering and improving the phenomenon of mixed discharge of nickel-lithium during the sintering process. It is also used to produce a small particle single-crystal material by crushing the large particle precursor after sintering, resulting in a more complete sintering process, reduced quasi-single-crystal formation, reduced side reactions, and the acquisition of a high-compression-density single-crystal material. In other words, it solves the problems of the high difficulty of sintering current single-crystal ternary material precursors and the reduction of quasi-single-crystal particle generation, making it advantageous for industrial production.

[0111] The following provides a specific method for manufacturing a cathode material precursor, which includes the following steps as shown in Figure 1.

[0112] Step 1 is the solution preparation step.

[0113] Depending on the molar ratios of Ni, Co, and Mn elements in the desired nickel-cobalt-manganese hydroxide, Ni-soluble salts, Co-soluble salts, and Mn-soluble salts were used as raw materials, and pure water was added to prepare nickel-cobalt-manganese salt mixtures with a concentration range of 1.2–2.7 mol / L.

[0114] Here, the molar ratio range of nickel-soluble salt, cobalt-soluble salt, and manganese-soluble salt is (88-96):(2-8):(2-8).

[0115] NaOH solutions with a concentration range of 1.0–13.0 mol / L were prepared as alkaline solutions.

[0116] NH3·H2O with a concentration range of 1.0–12.0 mol / L was prepared as a complexing agent.

[0117] In step 2, the jacket of the main reaction vessel with a volume range of 180-220 L is opened, and water is supplied and returned.

[0118] Step 3 is the stage in which the reaction bottom liquid is formed.

[0119] Pure water in a volume range of 90-110 L was added to the main reaction vessel, N2 was introduced into the main reaction vessel, the temperature range of the main reaction vessel was controlled to 50°C-70°C, the stirring speed range was set to 400-600 rpm, and then the NaOH solution and NH3·H2O solution prepared in step 1 were added to form the reaction bottom liquid.

[0120] Step 4 is the manufacturing stage for cathode material precursor particles.

[0121] In step 41, while continuously stirring, the NaOH solution, NH3·H2O solution, and mixed metal ion solution prepared in step 1 are added to the main reaction vessel in parallel at the first flow rate ratio to carry out the reaction. When the stirring speed range is 450-550 rpm, the reaction temperature, reaction atmosphere, pH of the reaction solution, and ammonia concentration are controlled to form seed crystals in the reaction vessel.

[0122] Here, the range of the first flow rate ratio is (0-9):(3-20):(20-133).

[0123] Step 42 is the pH reduction and stabilization growth stage. Once the amount of seed crystals reaches the target, the pH of the reaction mixture is lowered, and the reaction temperature, reaction atmosphere, pH of the reaction mixture, and ammonia concentration are continuously controlled to maintain the growth of seed crystal particles in the main reaction vessel.

[0124] In step 5, continue supplying according to step 4, and as shown in Figure 2, after the liquid level in the main reaction vessel reaches the filtration requirement, start the concentrator to begin filtration and maintain a stable liquid level in the main reaction vessel. When it is detected that the particle size of the material in the main reaction vessel has reached the required level, stop supplying the main reaction vessel, continue stirring, and allow to mature for 1-2 hours, then discharge the seed crystals into the pass slurry tank.

[0125] In step 6, the slurry in the passing slurry tank from step 5 is separated into solid and liquid phases, the separated filtration cake is washed with NaOH solution or KOH solution, and then washed again with pure water to obtain a washed filtration cake.

[0126] In step 7, the filtration cake washed in step 6 is dried in a drying machine, and then sequentially subjected to sieving and demagnetization to obtain porous, shoe-shaped nickel-cobalt-manganese hydroxide.

[0127] In a third embodiment, the embodiment of the present application provides a cathode material comprising the above-mentioned cathode material precursor.

[0128] The cathode material according to the embodiment of the present application allows lithium ions to penetrate sufficiently through precursor particles during the sintering process, resulting in more complete sintering. Furthermore, during crushing, large precursor particles are easily crushed by multiple small particles, reducing the difficulty of sintering. It also improves the phenomenon of mixed discharge of nickel-lithium during the sintering process. Additionally, it can be used to produce a small-particle single-crystal material by crushing large precursor particles after sintering, resulting in a more complete sintering process, reduced formation of quasi-single crystals, and reduced side reactions, thus obtaining a cathode material with high compressibility density, which is advantageous for industrial production.

[0129] In a fourth embodiment, an embodiment of the present application provides a secondary battery comprising a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, wherein the positive electrode sheet comprises the positive electrode material described above.

[0130] The embodiments of this invention provide a secondary battery with a long cycle life and excellent performance.

[0131] In some embodiments, the positive electrode sheet includes a current collector and a positive electrode material coated on the current collector, the positive electrode material is manufactured by sintering the positive electrode material precursor, a separator is provided between the positive electrode sheet and the negative electrode sheet, and an electrolyte is filled into the secondary battery.

[0132] The following examples illustrate the cathode material precursor, its manufacturing method, and its applications in the embodiments of this application. Example 1

[0133] This embodiment provides a method for producing a cathode material precursor, comprising the following steps.

[0134] In Step 1, Ni-soluble sulfate, Co-soluble sulfate, and Mn-soluble sulfate were selected in a molar ratio of 88:6:6 and mixed with deionized water to prepare a mixed metal sulfate solution with a concentration of 2.3 mol / L.

[0135] A NaOH solution with a concentration of 10.5 mol / L was prepared.

[0136] A solution of NH3·H2O with a concentration of 6 mol / L was prepared.

[0137] The NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were maintained at a constant temperature of 25°C.

[0138] In step 2, the jacket of the 180L reaction vessel is opened, and water is supplied and returned.

[0139] In step 3, 100 L of hot pure water was added to a 200 L reaction vessel, the temperature of the reaction vessel was controlled to 60°C, and the stirring speed was set to 500 rpm. Then, the NaOH solution and NH3·H2O solution were pumped into the reaction vessel, and the concentration of the NH3·H2O solution was maintained at 6.0 g / L before adding the alkali. The initial pH at 45°C was 11.60, and the reaction bottom liquid of the reaction vessel was prepared.

[0140] In step 4, after initiating the reaction, the flow rates of the NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were set to 9 mL / min, 3 mL / min, and 20 mL / min, respectively, and the reactions were carried out by continuously pumping them into a 60°C constant temperature reaction vessel via an input tank. The stirring speed was 500 rpm, the flow rate of the NaOH solution was adjusted to stabilize the pH value of the synthesis system at 11.5, and the flow rate of the NH3·H2O solution in the synthesis system was adjusted to maintain the NH3·H2O concentration of the synthesis system at 4.0 g / L. The N2 flow rate in the atmosphere liquid of the reaction vessel was adjusted to 150 L / h, and the air flow rate in the liquid was adjusted to 100 L / h, and the nucleation time was maintained at 3 min.

[0141] The stirring speed was set to 500 rpm, the flow rate of the NaOH solution was turned off, the pH value was quickly adjusted to 10.2, and then restored. The flow rate of the NH3·H2O solution was adjusted to maintain the NH3·H2O concentration in the synthesis system at 4.0 g / L, the N2 flow rate in the reaction vessel atmosphere was adjusted to 150 L / h, and the air flow rate in the liquid was adjusted to 100 L / h.

[0142] One hour after the start of the reaction, the flow rate of the mixed metal sulfate solution was adjusted and slowly increased to 267 mL / min over 6 hours. The flow rates of the NaOH solution and NH3·H2O solution were adjusted synchronously to stabilize the pH value at 10.2 and the ammonia value at 3.0. Four hours after the start of the reaction, the N2 flow rate in the reaction vessel atmosphere was adjusted to 100 L / h and the air flow rate in the liquid was set to 150 L / h. The oxygen content of the reaction atmosphere was increased by 1% every 4 hours. The stirring speed was gradually reduced based on the material particle size D50. When D50 reached 8 μm, the stirring speed was reduced and maintained at 200 rpm. When D50 reached 13.5-13.6 μm, the reaction was stopped to obtain a porous, puff-like large-particle ternary precursor slurry.

[0143] In step 5, a ternary precursor slurry that meets the particle size requirements is supplied to the intermediate tank and stirred.

[0144] In step 6, the ternary precursor slurry is subjected to alternating alkaline washing and pure water washing.

[0145] In step 7, the ternary precursor slurry is uniformly distributed in a drying apparatus and dried at a drying temperature of 120°C for a drying time of 12 hours, with two layers of 325 mesh screens.

[0146] By following the steps described above, a cathode material precursor with high aggregation, a porous and puff-like morphology, and an average particle size of 10-20 μm can be obtained, as shown in Figures 3-8. Example 2

[0147] This embodiment provides a method for producing a cathode material precursor, comprising the following steps.

[0148] In Step 1, Ni-soluble sulfate, Co-soluble sulfate, and Mn-soluble sulfate are selected in a molar ratio of 88:4:8 and mixed with deionized water to prepare a mixed metal sulfate solution with a concentration of 2.3 mol / L.

[0149] A NaOH solution with a concentration of 10.5 mol / L was prepared.

[0150] A solution of NH3·H2O with a concentration of 6 mol / L was prepared.

[0151] The NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were maintained at a constant temperature of 25°C.

[0152] In step 2, the jacket of the 180L reaction vessel is opened, and water is supplied and returned.

[0153] In step 3, 100 L of hot pure water was added to a 200 L reaction vessel, the temperature of the reaction vessel was controlled to 60°C, and the stirring speed was set to 500 rpm. Then, the NaOH solution and NH3·H2O solution were pumped into the reaction vessel, and the concentration of the NH3·H2O solution was maintained at 6.0 g / L before adding the alkali. The initial pH at 45°C was 11.60, and the reaction bottom liquid of the reaction vessel was prepared.

[0154] In step 4, after initiating the reaction, the flow rates of the NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were set to 0 mL / min, 20 mL / min, and 133 mL / min, respectively, and the reactions were carried out by continuously pumping them into a 60°C constant temperature reaction vessel via an input tank. The pH value was rapidly adjusted to 10.8 at a stirring speed of 500 rpm, and the flow rate of the NaOH solution was adjusted to stabilize the pH value of the synthesis system at 10.8. The flow rate of the NH3·H2O solution in the synthesis system was also adjusted to maintain the NH3·H2O concentration of the synthesis system at 6.0 g / L. The N2 flow rate in the atmosphere liquid of the reaction vessel was adjusted to 400 L / h, and the air flow rate in the liquid was also adjusted to 400 L / h.

[0155] One hour after the start of the reaction, the flow rate of the mixed metal sulfate solution was adjusted and slowly increased to 417 mL / min over 6 hours. The flow rates of the NaOH solution and NH3·H2O solution were adjusted synchronously to stabilize the pH value at 10.8 and the ammonia value at 6.0. Four hours after the start of the reaction, the N2 flow rate in the reaction vessel atmosphere was adjusted to 180 L / h, and the air flow rate in the liquid was set to 400 L / h. The oxygen content of the reaction atmosphere was increased by 1% every 4 hours. The stirring speed was gradually reduced based on the material particle size D50. When D50 reached 8 μm, the stirring speed was reduced and maintained at 200 rpm. When D50 reached 13.5-13.6 μm, the reaction was stopped to obtain a porous, puff-like large-particle ternary precursor slurry.

[0156] In step 5, a ternary precursor slurry that meets the particle size requirements is supplied to the intermediate tank and stirred.

[0157] In the next step, the ternary precursor slurry is subjected to alternating alkaline washing and pure water washing.

[0158] In step 7, the ternary precursor slurry is uniformly distributed in a drying apparatus and dried at a drying temperature of 120°C for a drying time of 12 hours, with two layers of 325 mesh screens.

[0159] By following the steps described above, a cathode material precursor with high aggregation, a porous and puff-like morphology, and an average particle size of 10-20 μm can be obtained, as shown in Figures 9-14. Example 3

[0160] This embodiment provides a method for producing a cathode material precursor, comprising the following steps.

[0161] In Step 1, Ni-soluble sulfate, Co-soluble sulfate, and Mn-soluble sulfate are selected in a molar ratio of 96:2:2 and mixed with deionized water to prepare a mixed metal sulfate solution with a concentration of 2.3 mol / L.

[0162] A NaOH solution with a concentration of 10.5 mol / L was prepared.

[0163] A solution of NH3·H2O with a concentration of 6 mol / L was prepared.

[0164] The NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were maintained at a constant temperature of 25°C.

[0165] In step 2, the jacket of the 180L reaction vessel is opened, and water is supplied and returned.

[0166] In step 3, 100 L of hot pure water was added to a 200 L reaction vessel, the temperature of the reaction vessel was controlled to 60°C, and the stirring speed was set to 500 rpm. Then, the NaOH solution and NH3·H2O solution were pumped into the reaction vessel, and the concentration of the NH3·H2O solution was maintained at 6.0 g / L before adding the alkali. The initial pH at 45°C was 11.60, and the reaction bottom liquid of the reaction vessel was prepared.

[0167] In step 4, after initiating the reaction, the flow rates of the NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were set to 0 mL / min, 20 mL / min, and 133 mL / min, respectively, and the reactions were carried out by continuously pumping them into a 60°C constant temperature reaction vessel via an input tank. The pH value was quickly adjusted to 11.3 at a stirring speed of 500 rpm, and the flow rate of the NaOH solution was adjusted to stabilize the pH value of the synthesis system at 11.3. The flow rate of the NH3·H2O solution was also adjusted to maintain the NH3·H2O concentration of the synthesis system at 9.0 g / L. The N2 flow rate in the atmosphere liquid of the reaction vessel was adjusted to 700 L / h, and the air flow rate in the liquid was also adjusted to 700 L / h.

[0168] One hour after the start of the reaction, the flow rate of the mixed metal sulfate solution was adjusted and slowly increased to 417 mL / min over 6 hours. The flow rates of the NaOH solution and NH3·H2O solution were adjusted synchronously to stabilize the pH value at 11.3 and the ammonia value at 9.0. Four hours after the start of the reaction, the N2 flow rate in the reaction vessel atmosphere was adjusted to 250 L / h, and the air flow rate in the liquid was set to 750 L / h. The oxygen content of the reaction atmosphere was increased by 1% every 4 hours. The stirring speed was gradually reduced based on the material particle size D50. When D50 reached 8 μm, the stirring speed was reduced and maintained at 200 rpm. When D50 reached 13.5-13.6 μm, the reaction was stopped to obtain a porous, puff-like large-particle ternary precursor slurry.

[0169] In step 5, a ternary precursor slurry that meets the particle size requirements is supplied to the intermediate tank and stirred.

[0170] In step 6, the ternary precursor slurry is subjected to alternating alkaline washing and pure water washing.

[0171] In step 7, the ternary precursor slurry is uniformly distributed in a drying apparatus and dried at a drying temperature of 120°C for a drying time of 12 hours, with two layers of 325 mesh screens.

[0172] By following the steps described above, a cathode material precursor with high aggregation, a porous and puff-like morphology, and an average particle size of 10-20 μm can be obtained, as shown in Figures 15-20. Comparative Example 1

[0173] This comparative example provides a method for producing a cathode material precursor, comprising the following steps.

[0174] In Step 1, Ni-soluble sulfate, Co-soluble sulfate, and Mn-soluble sulfate were selected in a molar ratio of 88:6:6 and mixed with deionized water to prepare a mixed metal sulfate solution with a concentration of 2.3 mol / L.

[0175] A NaOH solution with a concentration of 10.5 mol / L was prepared.

[0176] A solution of NH3·H2O with a concentration of 6 mol / L was prepared.

[0177] The NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were maintained at a constant temperature of 25°C.

[0178] In step 2, the jacket of the 180L reaction vessel is opened, and water is supplied and returned.

[0179] In step 3, 100 L of hot pure water was added to a 200 L reaction vessel, the temperature of the reaction vessel was controlled to 60°C, and the stirring speed was set to 500 rpm. Then, the NaOH solution and NH3·H2O solution were pumped into the reaction vessel, and the concentration of the NH3·H2O solution was maintained at 6.0 g / L before adding the alkali. The initial pH at 45°C was 11.60, and the reaction bottom liquid of the reaction vessel was prepared.

[0180] In step 4, after initiating the reaction, the flow rates of the NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were set to 0 mL / min, 20 mL / min, and 133 mL / min, respectively, and the reactions were carried out by continuously pumping them into a 60°C constant temperature reaction vessel via an input tank. The pH value was rapidly adjusted to 10.2 at a stirring speed of 500 rpm, the flow rate of the NaOH solution was adjusted so that the pH value of the synthesis system stabilized at 10.2, the flow rate of the NH3·H2O solution was adjusted so that the NH3·H2O concentration of the synthesis system was maintained at 4.0 g / L, and the N2 flow rate in the atmosphere liquid of the reaction vessel was adjusted to 150 L / h.

[0181] One hour after the reaction began, the flow rate of the mixed metal sulfate solution was adjusted and slowly increased to 417 mL / min over 6 hours. The flow rates of the NaOH solution and NH3·H2O solution were adjusted synchronously to stabilize the pH value at 10.2, and the ammonia value was set to 3.0. The N2 flow rate in the reaction vessel atmosphere was maintained at 150 L / h. The stirring speed was gradually reduced based on the particle size D50 of the material. When D50 reached 8 μm, the stirring speed was reduced and maintained at 200 rpm. When D50 reached 13.5-13.6 μm, the reaction was stopped, yielding a ternary precursor slurry with an average particle size of 10-20 μm.

[0182] In step 5, a ternary precursor slurry that meets the particle size requirements is supplied to the intermediate tank and stirred.

[0183] In step 6, the ternary precursor slurry is subjected to alternating alkaline washing and pure water washing.

[0184] In step 7, the ternary precursor slurry is uniformly distributed in a drying apparatus and dried at a drying temperature of 120°C for a drying time of 12 hours, with two layers of 325 mesh screens.

[0185] By following the steps described above, a large-particle cathode material precursor with a dense surface morphology, as shown in Figures 21-26, can be obtained. Comparative Example 2

[0186] This comparative example provides a method for producing a cathode material precursor, comprising the following steps.

[0187] In Step 1, Ni-soluble sulfate, Co-soluble sulfate, and Mn-soluble sulfate are selected in a molar ratio of 88:4:8 and mixed with deionized water to prepare a mixed metal sulfate solution with a concentration of 2.3 mol / L.

[0188] A NaOH solution with a concentration of 10.5 mol / L was prepared.

[0189] A solution of NH3·H2O with a concentration of 6 mol / L was prepared.

[0190] The NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were maintained at a constant temperature of 25°C.

[0191] In step 2, the jacket of the 180L reaction vessel is opened, and water is supplied and returned.

[0192] In step 3, 100 L of hot pure water was added to a 200 L reaction vessel, the temperature of the reaction vessel was controlled to 60°C, and the stirring speed was set to 500 rpm. Then, the NaOH solution and NH3·H2O solution were pumped into the reaction vessel, and the concentration of the NH3·H2O solution was maintained at 6.0 g / L before adding the alkali. The initial pH at 45°C was 11.60, and the reaction bottom liquid of the reaction vessel was prepared.

[0193] In step 4, after initiating the reaction, the flow rates of the NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were set to 0 mL / min, 20 mL / min, and 133 mL / min, respectively, and the reactions were carried out by continuously pumping them into a 60°C constant temperature reaction vessel via an input tank. The pH value was rapidly adjusted to 10.8 at a stirring speed of 500 rpm, the flow rate of the NaOH solution was adjusted so that the pH value of the synthesis system stabilized at 10.8, the flow rate of the NH3·H2O solution was adjusted so that the NH3·H2O concentration of the synthesis system was maintained at 6.0 g / L, and the N2 flow rate in the atmospheric liquid of the reaction vessel was adjusted to 400 L / h.

[0194] One hour after the reaction began, the flow rate of the mixed metal sulfate solution was adjusted and slowly increased to 417 mL / min over 6 hours. The flow rates of the NaOH solution and NH3·H2O solution were adjusted synchronously to stabilize the pH value at 10.8, and the ammonia value was set to 6.0. The N2 flow rate in the reaction vessel atmosphere was maintained at 400 L / h. The stirring speed was gradually reduced based on the particle size D50 of the material. When D50 reached 8 μm, the stirring speed was reduced and maintained at 200 rpm. When D50 reached 13.5-13.6 μm, the reaction was stopped, yielding a ternary precursor slurry with an average particle size of 10-20 μm.

[0195] In step 5, a ternary precursor slurry that meets the particle size requirements is supplied to the intermediate tank and stirred.

[0196] In step 6, the ternary precursor slurry is subjected to alternating alkaline washing and pure water washing.

[0197] In step 7, the ternary precursor slurry is uniformly distributed in a drying apparatus and dried at a drying temperature of 120°C for a drying time of 12 hours, with two layers of 325 mesh screens.

[0198] By following the steps described above, a large-particle cathode material precursor with a dense surface morphology, as shown in Figures 27-32, can be obtained. Comparative Example 3

[0199] This comparative example provides a method for producing a cathode material precursor, comprising the following steps.

[0200] In Step 1, Ni-soluble sulfate, Co-soluble sulfate, and Mn-soluble sulfate were selected in a molar ratio of 96:2:2 and mixed with deionized water to prepare a mixed metal sulfate solution with a concentration of 2.3 mol / L.

[0201] A NaOH solution with a concentration of 10.5 mol / L was prepared.

[0202] A solution of NH3·H2O with a concentration of 6 mol / L was prepared.

[0203] The NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were maintained at a constant temperature of 25°C.

[0204] In step 2, the jacket of the 180L reaction vessel is opened, and water is supplied and returned.

[0205] In step 3, 100 L of hot pure water was added to a 200 L reaction vessel, the temperature of the reaction vessel was controlled to 60°C, and the stirring speed was set to 500 rpm. Then, the NaOH solution and NH3·H2O solution were pumped into the reaction vessel, and the concentration of the NH3·H2O solution was maintained at 6.0 g / L before adding the alkali. The initial pH at 45°C was 11.60, and the reaction bottom liquid of the reaction vessel was prepared.

[0206] In step 4, after initiating the reaction, the flow rates of the NaOH solution, NH3·H2O solution, and mixed metal sulfate solution were set to 0 mL / min, 20 mL / min, and 133 mL / min, respectively, and the reactions were carried out by continuously pumping them into a 60°C constant temperature reaction vessel via an input tank. The pH value was rapidly adjusted to 11.3 at a stirring speed of 500 rpm, the flow rate of the NaOH solution was adjusted so that the pH value of the synthesis system stabilized at 11.3, the flow rate of the NH3·H2O solution was adjusted so that the NH3·H2O concentration of the synthesis system was maintained at 9.0 g / L, and the N2 flow rate in the reaction vessel atmosphere was adjusted to 700 L / h.

[0207] One hour after the reaction began, the flow rate of the mixed metal sulfate solution was adjusted and slowly increased to 417 mL / min over 6 hours. The flow rates of the NaOH solution and NH3·H2O solution were adjusted synchronously to stabilize the pH value at 11.3, and the ammonia value was set to 9.0. The N2 flow rate in the reaction vessel atmosphere was maintained at 700 L / h. The stirring speed was gradually reduced based on the particle size D50 of the material. When D50 reached 8 μm, the stirring speed was reduced and maintained at 200 rpm. When D50 reached 13.5-13.6 μm, the reaction was stopped, yielding a ternary precursor slurry with an average particle size of 10-20 μm.

[0208] In step 5, a ternary precursor slurry that meets the particle size requirements is supplied to the intermediate tank and stirred.

[0209] In step 6, the ternary precursor slurry is subjected to alternating alkaline washing and pure water washing.

[0210] In step 7, the ternary precursor slurry is uniformly distributed in a drying apparatus and dried at a drying temperature of 120°C for a drying time of 12 hours, with two layers of 325 mesh screens.

[0211] By following the steps described above, a large-particle cathode material precursor with a dense surface morphology, as shown in Figures 33-38, can be obtained.

[0212] The cathode material precursors produced in Examples 1-3 and Comparative Examples 1-3 of this application were subjected to Ni content, Co content, Mn content, sodium (Na) content, sulfur (S) content, specific surface area measurement (BET), and thermal desorption measurement (TD), respectively, and the results are shown in Table 1 below. [Table 1]

[0213] As can be seen from Table 1, the main content results for Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 are similar. Examples 1-3 have a larger specific surface area, lower sodium content, lower sulfur content, and less thermal desorption than Comparative Examples 1-3.

[0214] As can be seen from the electron microscope images in Figures 3-38, under oxidation conditions, the whiskers on the particle surface in Examples 1-3 were thin and sparse, making it easier to remove impurities such as sodium and sulfur during the washing process. Furthermore, because the whiskers on the particle surface in Examples 1-3 were sparse, the strength of the precursor was reduced, the particles were more easily crushed, the difficulty of sintering the cathode was reduced, and sintering was more complete.

[0215] In Figure 5, the darker color indicates a high particle density, suggesting that lithium ions migrate within the larger particles and are distributed relatively uniformly.

[0216] Here, we will only introduce the content related to the invention; other information can be obtained by referring to related technologies, and therefore, detailed explanations are omitted here.

[0217] The foregoing are merely selectable embodiments of the present invention and do not limit it. To those skilled in the art, the present invention is subject to various modifications and changes. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims.

Claims

1. A cathode material precursor, The positive electrode material precursor comprises precursor particles formed by the aggregation of a plurality of first particles, and the first particles have a core-shell structure having a core and a surface layer. The core has a dense seed crystal, The surface layer has a plurality of whiskers, and there are gaps between adjacent whiskers. A cathode material precursor characterized by the following features.

2. The cathode material precursor according to claim 1, characterized in that the ratio of the particle size of the seed crystal to the particle size of the first particle is in the range of 30%-40%.

3. The cathode material precursor according to claim 1, characterized in that the ratio of the particle size of the first particle to the particle size of the precursor particle is in the range of 20%-50%.

4. The cathode material precursor according to claim 1, characterized in that the thickness range of the whiskers is 10 nm to 30 nm.

5. The specific surface area range of the aforementioned precursor particles is 20 m². 2 / g-40m 2 The cathode material precursor according to claim 1, characterized in that it is / g.

6. The cathode material precursor according to any one of claims 2-5, characterized in that the precursor particles further include a shell layer that covers the surface layer of the core-shell structure.

7. The cathode material precursor according to claim 6, characterized in that the thickness range of the shell layer is 0.2 μm to 0.5 μm.

8. The cathode material precursor according to any one of claims 2 to 5, characterized in that the thickness of the core of the core-shell structure is in the range of 4 μm to 8 μm.

9. A method for producing a positive electrode material precursor, The positive electrode material precursor is manufactured from the following steps: A mixed metal ion solution is obtained by mixing multiple metal ion sources with water, and a first alkaline solution and a complexing agent are prepared separately. After adding water to the reactor and introducing a protective gas, the first alkaline solution and the complexing agent are added to form the reaction bottom liquid. The first alkaline solution, the complexing agent, and the mixed metal ion solution are added to the reactor in parallel to carry out a nucleation reaction, the reaction atmosphere is controlled to a first atmosphere to form seed crystals, and when it is detected that the seed crystal content has reached the target, the pH of the reaction solution is lowered and the reaction atmosphere is controlled to a second atmosphere to maintain the growth reaction of seed crystal granules. The system continuously supplies the material, performs filtration after detecting that the liquid level in the reactor has reached the filtration requirement, maintains a stable liquid level in the reactor, and stops supplying the material when it is detected that the particle size of the material in the reactor has reached the target, and discharges the material into the container. The material in the container is subjected to solid-liquid separation, and the separated filtration cake is processed to obtain the cathode material precursor. A method for producing a cathode material precursor, characterized by the above.

10. The method for producing a cathode material precursor according to claim 9, characterized in that the first atmosphere includes at least the protective gas, and the second atmosphere includes air and the protective gas.

11. The method for producing a cathode material precursor according to claim 9, characterized in that, in the second atmosphere, the airflow rate gradually increases with increasing material solid content.

12. The method for producing a cathode material precursor according to claim 10, characterized in that the air flow rate range of the first atmosphere is 0 L / h to 800 L / h, and the protective gas flow rate range of the first atmosphere is 100 L / h to 800 L / h.

13. The method for producing a cathode material precursor according to claim 10, characterized in that the air flow rate range of the second atmosphere is 300 L / h to 800 L / h, and the protective gas flow rate range of the second atmosphere is 0 L / h to 300 L / h.

14. The method for producing a cathode material precursor according to claim 12 or 13, characterized in that the concentration range of the complexing agent in the nucleation reaction is 2.0 g / L to 10.0 g / L.

15. The method for producing a cathode material precursor according to claim 12 or 13, characterized in that the concentration range of the complexing agent in the growth reaction is 1.0 g / L to 10.0 g / L.

16. The method for producing a cathode material precursor according to claim 12 or 13, characterized in that the flow rate range of the mixed metal ion solution is 0.5 L / h to 40 L / h.

17. The method for producing a positive electrode material precursor according to claim 12 or 13, characterized in that the flow rate ratio of the first alkaline solution, the complexing agent, and the mixed metal ion solution is in the range of 0-9:3-20:20-133.

18. The method for producing a cathode material precursor according to claim 12 or 13, characterized in that the pH range of the reaction solution is 10.0-11.

5.

19. A cathode material characterized by comprising a cathode material precursor according to any one of claims 1 to 8, or a cathode material precursor manufactured by the method described in any one of claims 9 to 18.

20. It is a secondary battery, The secondary battery comprises a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, wherein the positive electrode sheet comprises the positive electrode material described in claim 19.

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