A high-nickel positive electrode material precursor, a preparation method thereof, and a high-nickel positive electrode material

Abstract

The application discloses a high-nickel positive electrode material precursor, a preparation method thereof and a high-nickel positive electrode material, wherein a (001) face lattice strain parameter epsilon of the high-nickel positive electrode material precursor is in the range of 0-10%, wherein the (001) face lattice strain parameter epsilon = Delta d / d = -cot theta*Delta theta, d is a standard crystal face spacing, Delta d is a difference value between a sample crystal face spacing and the standard crystal face spacing, theta is a standard diffraction angle, and Delta theta is a deviation diffraction angle. In the application, fresh precursor crystal nuclei are ball-milled and heat-aged, the stacking order of primary particles is adjusted in the process of dissolving-recrystallization of the precursor crystal nuclei, and residual stress is further released, so that the high-nickel positive electrode material precursor with a low lattice strain parameter can be obtained. The above high-nickel positive electrode material precursor is not prone to cracking in the sintering process and the process of lithium extraction in the charge-discharge cycle, the capacity "dive" of the prepared high-nickel positive electrode material can be effectively inhibited, and the high-nickel positive electrode material has good cycle stability.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and more specifically, to a high-nickel cathode material precursor, its preparation method, and the high-nickel cathode material. Background Technology

[0002] With the rapid development of industries such as new energy vehicles, low-altitude aircraft, and intelligent personalization, the market demand for high-nickel ternary materials continues to rise. As a core intermediate in the preparation of ternary cathode materials for lithium-ion batteries, the crystal structure, morphology, particle size, and crystallinity of ternary precursors directly determine the electrochemical performance of the final ternary cathode material, thus affecting the energy density, cycle life, and safety performance of power batteries. Therefore, the industry has placed higher demands on the precise control of the crystal structure of ternary precursors. Consequently, developing stable and controllable ternary precursor crystal structure regulation technology has become a current research hotspot and technological bottleneck in the field of lithium battery materials.

[0003] Currently, the mainstream preparation method for ternary precursors is co-precipitation, which controls the precursor morphology and grain growth by adjusting process parameters such as pH, ammonia concentration, temperature, and stirring speed. Existing technologies have attempted to control precursor morphology through process parameter regulation: for example, by formulaically controlling the ammonia value to regulate different whisker morphologies, or by controlling the reaction atmosphere during co-precipitation to regulate particle pore structure and improve impurity removal efficiency. However, existing technologies still have many unresolved technical drawbacks. Due to the significant differences in the solubility products of Ni, Co, and Mn / Al, precursor element segregation, poor crystallinity, or stress concentration occur, ultimately affecting the electrochemical performance and stability of the battery. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems existing in the prior art and to provide a high-nickel cathode material precursor, its preparation method, and the high-nickel cathode material.

[0005] The technical problem solved by this invention is achieved by the following technical solution.

[0006] This invention provides a high-nickel cathode material precursor, wherein the (001) plane lattice strain parameter ε of the high-nickel cathode precursor is in the range of 0-10%, wherein: (001) The lattice strain parameter ε = Δd / d = -cotθ × Δθ, where d is the standard interplanar spacing, Δd is the difference between the sample interplanar spacing and the standard interplanar spacing, θ is the standard diffraction angle, and Δθ is the offset diffraction angle.

[0007] The present invention provides a method for preparing the above-mentioned high-nickel cathode material precursor, comprising the following steps: after ball milling and thermal aging of the precursor nuclei prepared by co-precipitation method, the precursor nuclei are mixed again with a mixed metal salt solution, a precipitant and a complexing agent to carry out a secondary co-precipitation reaction to obtain the high-nickel cathode material precursor.

[0008] This invention provides a high-nickel cathode material, which is prepared by sintering a mixture of the above-mentioned high-nickel cathode material precursor and a lithium salt.

[0009] The present invention has the following beneficial effects: In this invention, fresh precursor nuclei are ball-milled and thermally aged. During the nuclei dissolution-recrystallization process, the orderliness of particle stacking is adjusted, and residual stress is further released. This yields a high-nickel cathode material precursor with a low lattice strain parameter. Using this high-nickel cathode material precursor, cracking is less likely during sintering and charge-discharge cycle lithium insertion / extraction, effectively suppressing the capacity drop of the prepared high-nickel cathode material and giving it better cycle stability. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is one of the SEM images of the high-nickel cathode material precursor obtained in Example 1 of the present invention; Figure 2 This is the second SEM image of the high-nickel cathode material precursor obtained in Example 1 of the present invention; Figure 3 This is a SEM image of the high-nickel cathode material precursor obtained in Comparative Example 1 of this invention; Figure 4 The image shows the XRD pattern of the high-nickel cathode material precursor obtained in Example 1 of this invention. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0013] The following is a detailed description of a high-nickel cathode material precursor, its preparation method, and the high-nickel cathode material provided by embodiments of the present invention.

[0014] In a first aspect, the present invention provides a high-nickel cathode material precursor, wherein the (001) plane lattice strain parameter ε of the high-nickel cathode precursor is in the range of 0-10%, wherein: (001) The lattice strain parameter ε = Δd / d = -cotθ × Δθ, where d is the standard interplanar spacing, Δd is the difference between the sample interplanar spacing and the standard interplanar spacing, θ is the standard diffraction angle, and Δθ is the offset diffraction angle.

[0015] The high-nickel cathode material precursor provided above improves the stacking order of primary particles through a single particle rearrangement and stress relief, thereby obtaining a high-nickel cathode material precursor with a low lattice strain parameter. The above-mentioned high-nickel cathode material precursor is not prone to cracking during the sintering process and the lithium insertion / extraction process of charge-discharge cycles, effectively suppressing the capacity "plummeting" of the prepared high-nickel cathode material and giving it good cycle stability.

[0016] In some optional embodiments, the high-nickel cathode material precursor includes secondary particles formed by stacking multiple primary particles. The primary particles have a plate-like morphology, and the average stacking angle between the primary particles is 50°-70°, with a stacking angle deviation σ≤0.6, where σ is the root mean square deviation of the primary particle stacking angle. The high-nickel cathode material precursor provided above features a predominantly triangular, ordered stacking of primary particles with a small stacking angle deviation. This structure can effectively reduce structural collapse during the sintering or cyclic charge-discharge process of the high-nickel cathode material prepared using it, while ensuring the lithium-ion transport channel, thereby effectively improving the capacity and cycle performance of the high-nickel cathode material.

[0017] In some alternative implementations, the percentage of cracked particles is ≤1% based on the SEM image of the high-nickel cathode material precursor.

[0018] In some alternative embodiments, the high-nickel cathode material precursor is composed of Ni x Co y Mn (1-x-y) (OH)₂, where: 0.6≤x≤1, 0≤y<0.4, D 50 The range is 2μm-20μm, and the BET value is 3m. 2 / g-30m 2 / g, TD is 0.8g / cm 3 -2.4g / cm 3 .

[0019] Secondly, the present invention provides a method for preparing the above-mentioned high-nickel cathode material precursor, comprising the following steps: after ball milling and thermal aging of the precursor nuclei prepared by the co-precipitation method, the precursor nuclei are mixed again with a mixed metal salt solution, a precipitant and a complexing agent to carry out a secondary co-precipitation reaction to obtain the high-nickel cathode material precursor.

[0020] The above-described method for preparing high-nickel cathode material precursors involves ball milling and thermal aging of fresh precursor nuclei. During the nuclei dissolution-recrystallization process, the orderliness of particle stacking is adjusted once, while residual stress is further released, resulting in high-nickel cathode material precursors with lower lattice strain parameters.

[0021] In some alternative implementations, the following steps are included: Step 1: The metal salt solution, complexing agent, and precipitant are co-flowed into the first microchannel reactor for co-precipitation reaction, and the precursor nucleus slurry is obtained at the outlet of the first microchannel reactor. Step 2: The precursor nucleus slurry obtained in Step 1 is fed into a continuous hot sand mill for stress relief to obtain a pretreated nucleus slurry. Step 3: The pretreated nucleus slurry obtained in Step 2 is fed into the second microchannel reactor in parallel with the metal salt solution, complexing agent, and precipitant for a secondary co-precipitation reaction. The high-nickel cathode precursor finished slurry is obtained at the outlet of the second microchannel reactor. Step 4: Wash, dry, and sieve the high-nickel cathode precursor slurry obtained in Step 3 to obtain the high-nickel cathode material precursor.

[0022] In the preparation of high-nickel cathode material precursors using the co-precipitation method, the significant differences in the solubility products of Ni, Co, and Mn / Al mean that traditional reactors, such as stirred tank reactors, suffer from mass transfer effects. Micro-mixing requires considerable time, and homogenization is difficult to control precisely. This uneven precipitation directly impacts grain accumulation, leading to precursor element segregation, poor crystallinity, or stress concentration, ultimately affecting the electrochemical performance and stability of the battery. Therefore, this invention abandons the stirred tank reactor and employs a microfluidic reactor, which boasts extremely high heat and mass transfer efficiency, resulting in high reaction uniformity and stability. Combining ball milling and thermal aging effectively reduces stress accumulation during product growth, thereby improving product morphology uniformity and reducing the risk of particle cracking.

[0023] In some alternative embodiments, in step 1, the temperature of the coprecipitation reaction is 40-70°C, the pH is 9-13, and the reaction time is 30s-600s; The total molar concentration of metal ions in the metal salt solution is 1.2 mol / L-2.5 mol / L. The precipitant includes an aqueous solution of sodium hydroxide with a mass concentration of 20%-40%, and the complexing agent includes an aqueous solution of ammonia with a mass concentration of 10%-20%.

[0024] In some alternative embodiments, in step 2, the ball-to-material ratio is adjusted to 1:1-6:1, the ball milling temperature is 50℃-80℃, the ball milling speed is 50-800 rpm, and the ball milling time is 10 min-120 min.

[0025] In some optional embodiments, in step 3, the temperature of the secondary coprecipitation reaction is 50℃-80℃, the pH is 9-12, the reaction time is 30s-1800s, the proportion of solid crystal nuclei in the precursor crystal nucleus slurry to the total output is 15%-55%, and the process parameters of step 3 and step 1 also satisfy: reaction temperature T3-T1=10-20℃, reaction pH3-pH1=~1.9-~1.3, and reaction time t3 / t1=1-3; The total molar concentration of metal ions in the metal salt solution is 1.2 mol / L-2.5 mol / L. The precipitant includes an aqueous solution of sodium hydroxide with a mass concentration of 20%-40%, and the complexing agent includes an aqueous solution of ammonia with a mass concentration of 10%-20%.

[0026] In some alternative embodiments, in step 4, the detergent used for washing is a sodium hydroxide aqueous solution with a mass fraction of 3%-5% at a temperature of 50°C-80°C and pure water at a temperature of 50°C-80°C. The drying temperature is 80°C-150°C.

[0027] The present invention provides a method for preparing a high-nickel cathode material precursor. The precursor particles undergo three stages during growth: precursor nucleus formation, stress relief of the precursor nucleus, and secondary growth. After stress relief of the precursor nucleus, if the process conditions are not changed, the surface state will change as the precursor particle radius increases, thus affecting the product morphology and structure; that is, the product will undergo spontaneous morphological changes. By limiting the process conditions of steps 3 and 1, the reaction environment of the precursor nucleus is altered, allowing the internal and external structures of the particles to maintain a relatively similar structure and morphology, thereby avoiding stress concentration caused by changes in internal and external structure and reducing the number of particle cracks.

[0028] Thirdly, the present invention provides a high-nickel cathode material, which is formed by sintering the above-mentioned high-nickel cathode material precursor with lithium salt.

[0029] In some alternative embodiments, a high-nickel cathode material precursor is mixed with a lithium salt at a molar ratio of 1:(1.01-1.10) and sintered at 650°C-980°C for 6-20 hours. Using the aforementioned high-nickel cathode material precursor helps suppress crack formation during the sintering of the high-nickel cathode material precursor and the repeated insertion / extraction of lithium ions, thereby significantly improving the cycle performance of the battery.

[0030] The present invention will be further described below with reference to embodiments.

[0031] Example 1 A process for preparing a high-nickel cathode material precursor includes the following steps: Step 1. Dissolve nickel sulfate, cobalt sulfate, and manganese sulfate in pure water at a ratio of 95:3:2 to prepare a 2 mol / L mixed metal salt solution.

[0032] Step 2. The mixed metal salt solution, 16% ammonia water, and 32% sodium hydroxide solution obtained in Step 1 are fed into the microfluidic reactor in a co-current manner. The reaction temperature is controlled at 50°C, the pH is maintained at 11.5, and the reaction time is controlled at 300s. The precursor crystal nucleus slurry is continuously obtained at the outlet of the microfluidic reactor.

[0033] Step 3. Pass the precursor nucleus slurry obtained in Step 2 into a continuous sand mill jar, add zirconia balls with a diameter of 3 mm, control the ball-to-material ratio to be 1:1, the ball milling temperature to be 60℃, the ball milling speed to be 100 rpm, and the ball milling time to be 10 min, to obtain the pretreated nucleus slurry.

[0034] Step 4. The pretreated nucleus slurry obtained in Step 3 is fed into the microchannel reactor 2 in parallel with the metal salt solution, 16% ammonia water and 32% sodium hydroxide solution for growth. The reaction temperature is controlled at 68℃, the pH is maintained at 10.2, the reaction time is controlled at 600s, and the nucleus addition amount is 20%. The high-nickel cathode material precursor slurry is obtained at the outlet of the microchannel reactor.

[0035] Step 5. Wash the pretreated high-nickel cathode material precursor slurry obtained in Step 4 in a centrifuge, successively with a 3% sodium hydroxide solution at 70°C and pure water at 70°C, and then spin dry; place the filter cake in an oven and dry it at 100°C for 8 hours to obtain the high-nickel cathode material precursor product, whose composition is Ni. 0.95 Co 0.03 Mn 0.02 (OH)2, SEM image as follows Figures 1-2 As shown, the high-nickel cathode material precursor product contains virtually no cracked particles, forming an ordered stack of primary particles that are secondary particles. The XRD pattern is shown below. Figure 4 As shown, the calculated lattice strain parameter ε of the (001) plane is 5.85%.

[0036] The preparation process of a high-nickel cathode material includes the following steps: Lithium carbonate was mixed with the above-mentioned high-nickel cathode material precursor at a molar ratio of 1.05:1 and sintered in a muffle furnace at 860°C in air for 12 hours. The sintered material was then crushed and sieved to obtain the finished high-nickel cathode material.

[0037] Example 2 A process for preparing a high-nickel cathode material precursor includes the following steps: Step 1. Dissolve nickel sulfate, cobalt sulfate, and manganese sulfate in pure water at a ratio of 80:10:10 to prepare a 2 mol / L mixed metal salt solution.

[0038] Step 2. The mixed metal salt solution, 16% ammonia water, and 32% sodium hydroxide solution obtained in Step 1 are fed into the microfluidic reactor in a co-current manner. The reaction temperature is controlled at 60°C, the pH is maintained at 11.4, and the reaction time is controlled at 300s. The precursor crystal nucleus slurry is continuously obtained at the outlet of the microfluidic reactor.

[0039] Step 3. Pass the precursor nucleus slurry obtained in Step 2 into a continuous sand mill jar, add zirconia balls with a diameter of 3 mm, control the ball-to-material ratio at 1.5:1, the ball milling temperature at 65℃, the ball milling speed at 150 rpm, and the ball milling time at 10 min to obtain the pretreated nucleus slurry.

[0040] Step 4. The pretreated nucleus slurry obtained in Step 3 is fed into the microchannel reactor 2 in parallel with the metal salt solution, 16% ammonia water and 32% sodium hydroxide solution for growth. The reaction temperature is controlled at 72℃, the pH is maintained at 10.1, the reaction time is controlled at 500s, and the amount of nuclei added is 15%. The high-nickel cathode precursor slurry is obtained at the outlet of the microchannel reactor.

[0041] Step 5. Wash the pretreated high-nickel cathode material precursor slurry obtained in Step 4 in a centrifuge, successively with a 3% sodium hydroxide solution at 70°C and pure water at 70°C, and then spin dry; place the filter cake in an oven and dry it at 100°C for 8 hours to obtain the high-nickel cathode material precursor product with the composition Ni 0.8 Co 0.1 Mn 0.1 (OH)2.

[0042] The preparation process of a high-nickel cathode material includes the following steps: Lithium carbonate was mixed with the above-mentioned high-nickel cathode material precursor at a molar ratio of 1.05:1 and sintered in a muffle furnace at 860°C in air for 12 hours. The sintered material was then crushed and sieved to obtain the finished high-nickel cathode material.

[0043] Comparative Example 1 Similar to the steps in Example 1, except that step 3 is not included. The SEM image of the high-nickel cathode material precursor is shown below. Figure 3 As shown, it can be seen that the high-nickel cathode material precursor contains obviously cracked secondary particles.

[0044] Comparative Example 2 The steps are similar to those in Example 1, except that the ball-to-material ratio in step 3 is 1:2.

[0045] Comparative Example 3 The steps are similar to those in Example 1, except that the ball milling temperature in step 3 is 40°C.

[0046] Comparative Example 4 Similar to the steps in Example 1, except that the amount of precursor crystal nuclei introduced in step 4 is 10%.

[0047] Comparative Example 5 Similar to the steps in Example 1, except that the amount of precursor crystal nuclei introduced in step 4 is 60%.

[0048] Comparative Example 6 The steps are similar to those in Example 1, except that the reaction temperature in step 4 is 55°C.

[0049] Comparative Example 7 The steps are similar to those in Example 1, except that the reaction pH in step 4 is 10.6.

[0050] Comparative Example 8 The steps are similar to those in Example 1, except that the reaction time in step 4 is 100 seconds.

[0051] The results of the lattice strain parameters, cracked particle ratio, primary particle stacking angle, and primary particle stacking angle deviation of the high-nickel cathode material precursor obtained from the above embodiments and comparative examples are shown in Table 1 below. The formula for calculating the lattice strain parameter ε of the (001) plane is as follows: ε = Δd / d = -cotθ × Δθ, where d is the standard interplanar spacing, Δd is the difference between the sample interplanar spacing and the standard interplanar spacing, θ is the standard diffraction angle, and Δθ is the offset diffraction angle. Cracked particle ratio: obtained statistically from SEM images of the high-nickel cathode material precursor. Primary particle stacking angle: statistically obtained from SEM images containing only one secondary sphere (e.g., ...). Figure 2 In the figure shown, calculate the included angle between any two adjacent or intersecting plate-like primary particles on the surface of the secondary sphere, and calculate the average value and standard deviation.

[0052] Table 1. Relevant indicators of precursors prepared in the examples and comparative examples.

[0053] As shown in Table 1 above, compared to Comparative Example 1, the 001 plane lattice strain parameter and the number of cracked particles in the high-nickel cathode material precursor prepared using the method of Example 1 are significantly reduced. This indicates that using stress-relieved precursor nuclei for subsequent secondary co-precipitation reactions can effectively reduce internal stress accumulation and crack formation in the high-nickel cathode material precursor product. In Comparative Examples 2-8, except for Comparative Example 5, the 001 plane lattice strain parameter, the number of cracked particles, and the average stacking angle and stacking angle deviation of the primary particles in the modified process parameters could not simultaneously meet the requirements. The reasons are as follows: without ball milling and thermal aging, or with insufficient temperature and intensity (ball-to-material ratio) during ball milling and thermal aging, the stress of the precursor nuclei cannot be eliminated; when the amount of precursor nuclei added is small, the growth rate for each precursor nucleus is faster, and structural defects are more likely to occur during the growth process; when the process in the growth stage is not within the set range, it is impossible to offset the influence of the surface state changes during secondary particle growth on the morphology and structure, thereby causing stress accumulation due to changes in the internal and external structure of the particles. All of these product indicators will affect the electrical performance of high-nickel cathode materials.

[0054] The high-nickel cathode materials obtained in the examples and comparative examples were subjected to electrochemical performance testing according to the following methods: High-nickel cathode material, conductive agent (acetylene black), and binder (PVDF) were mixed and dispersed in an organic solvent NMP at a ratio of 90:5:5. After stirring evenly, the mixture was coated onto aluminum foil to form a cathode sheet. A lithium sheet was used as the anode. A button cell was fabricated in a glove box under a protective atmosphere. The electrical performance was tested on a battery testing system, and the test results are shown in Table 2. Table 2. Percentage of Cracked Particles and Electrical Performance Results of High-Nickel Cathode Materials

[0055] As can be seen from Table 2 above, the high-nickel cathode material prepared by the method provided in Examples 1-2 has a relatively small number of particle cracks and a high cycle capacity retention rate. This indicates that the prepared high-nickel cathode material precursor meets the requirements of low internal stress, fewer cracks, and orderly primary particle stacking, which significantly improves the cycle performance of the high-nickel cathode material.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-nickel cathode material precursor, characterized in that, The lattice strain parameter ε of the (001) plane of the high-nickel cathode precursor is in the range of 0-10%, where: (001) The lattice strain parameter ε = Δd / d = -cotθ × Δθ, where d is the standard interplanar spacing, Δd is the difference between the sample interplanar spacing and the standard interplanar spacing, θ is the standard diffraction angle, and Δθ is the offset diffraction angle.

2. The high-nickel cathode material precursor according to claim 1, characterized in that, The high-nickel cathode material precursor includes secondary particles formed by stacking multiple primary particles. The primary particles have a plate-like morphology, and the average stacking angle between the primary particles is 50°-70°, with a stacking angle deviation σ≤0.6, where σ is the root mean square deviation of the stacking angle of the primary particles.

3. The high-nickel cathode material precursor according to claim 1, characterized in that, According to the SEM images of the high-nickel cathode material precursor, the percentage of cracked particles is ≤1%.

4. The high-nickel cathode material precursor according to claim 1, characterized in that, The high-nickel cathode material precursor is composed of Ni x Co y Mn (1-x-y) (OH)₂, where: 0.6≤x≤1, 0≤y<0.4, D 50 The range is 2μm-20μm, and the BET value is 3m. 2 / g-30m 2 / g, TD is 0.8g / cm 3 -2.4g / cm 3 .

5. A method for preparing a high-nickel cathode material precursor according to any one of claims 1-4, characterized in that, Includes the following steps: The precursor nuclei prepared by the co-precipitation method were ball-milled and thermally aged, and then mixed with a mixed metal salt solution, precipitant, and complexing agent to carry out a second co-precipitation reaction to prepare a high-nickel cathode material precursor.

6. The preparation method according to claim 5, characterized in that, Includes the following steps: Step 1: The metal salt solution, complexing agent, and precipitant are co-flowed into the first microchannel reactor for co-precipitation reaction, and the precursor nucleus slurry is obtained at the outlet of the first microchannel reactor; Step 2: The precursor nucleus slurry obtained in Step 1 is fed into a continuous hot sand mill for stress relief to obtain a pretreated nucleus slurry. Step 3: The pretreated nucleus slurry obtained in Step 2 is fed into the second microchannel reactor in parallel with the metal salt solution, complexing agent, and precipitant for a secondary co-precipitation reaction. The high-nickel cathode precursor finished slurry is obtained at the outlet of the second microchannel reactor. Step 4: Wash, dry, and sieve the high-nickel cathode precursor slurry obtained in Step 3 to obtain the high-nickel cathode material precursor.

7. The preparation method according to claim 6, characterized in that, In step 1, the temperature of the coprecipitation reaction is 40-70℃, the pH is 9-13, and the reaction time is 30s-600s; The total molar concentration of metal ions in the metal salt solution is 1.2 mol / L-2.5 mol / L, the precipitant includes an aqueous sodium hydroxide solution with a mass concentration of 20%-40%, and the complexing agent includes an aqueous ammonia solution with a mass concentration of 10%-20%.

8. The preparation method according to claim 6, characterized in that, In step 2, adjust the ball-to-material ratio to 1:1-6:1, the ball milling temperature to 50℃-80℃, the ball milling speed to 50-800 rpm, and the ball milling time to 10 min-120 min.

9. The preparation method according to claim 6, characterized in that, In step 3, the temperature of the secondary coprecipitation reaction is 50℃-80℃, the pH is 9-12, and the reaction time is 30s-1800s. The proportion of solid crystal nuclei in the precursor crystal nucleus slurry to the total output is 15%-55%. The process parameters of step 3 and step 1 also meet the following requirements: reaction temperature T3-T1=10-20℃, reaction pH3-pH1=~1.9-~1.3, and reaction time t3 / t1=1-3. The total molar concentration of metal ions in the metal salt solution is 1.2 mol / L-2.5 mol / L, the precipitant includes an aqueous sodium hydroxide solution with a mass concentration of 20%-40%, and the complexing agent includes an aqueous ammonia solution with a mass concentration of 10%-20%.

10. A high-nickel cathode material, characterized in that, It is prepared by sintering a high-nickel cathode material precursor according to any one of claims 1-4 with a lithium salt.

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