阅读说明：本技术 钠、硫杂质含量低的富镍大粒径三元前驱体的制备方法 (Preparation method of nickel-rich large-particle-size ternary precursor with low sodium and sulfur impurity content ) 是由 侯鑫宇 刘宙 张海艳 胡志兵 黎力 孟立君 张娉婷 于 2021-10-26 设计创作，主要内容包括：本发明属于锂离子电池材料技术领域,具体涉及一种钠、硫杂质含量低的富镍大粒径三元前驱体的制备方法。本发明通过控制pH降低速率及pH降低幅度来切换成核及晶体生长阶段,在成核阶段形成细小颗粒的疏松团聚体。将pH值降低至目标范围后,前驱体开始转换为晶体生长阶段,后续新生成的沉淀物将在原有的二次颗粒上生长。共沉淀得到的前驱体,存在从颗粒表面至内核径向的裂纹,在洗涤过程中为杂质离子的去除提供了通道,使得颗粒内部的Na～(+)及SO-(4)～(2-)得以有效去除。在陈化过程中,将上层清夜与洗涤后的前驱体混合,通入碱液进行陈化反应,前驱体表面颗粒裂纹得到修复。该前驱体经混锂烧结成正极材料后,无开裂现象。(The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a preparation method of a nickel-rich large-particle-size ternary precursor with low sodium and sulfur impurity contents. The invention switches the nucleation and crystal growth stages by controlling the pH reduction rate and the pH reduction amplitude, and forms loose aggregates of fine particles in the nucleation stage. After the pH value is reduced to the target range, the precursor begins to be converted into a crystal growth stage, and subsequently newly generated precipitates grow on the original secondary particles. The precursor obtained by coprecipitation has radial cracks from the surface to the inner core of the particle, and provides a passage for removing impurity ions in the washing process, so that Na in the particle + And SO 4 2‑ Are effectively removed. And in the aging process, mixing the supernatant with the washed precursor, introducing alkali liquor for aging reaction, and repairing the cracks on the particles on the surface of the precursor. The precursor is sintered into the anode material through lithium mixing, and the cracking phenomenon is avoided.)

1. A preparation method of a nickel-rich large-particle-size ternary precursor with low sodium and sulfur contents is characterized by comprising the following steps of:

step S1, according to molecular formula Ni_xCo_yMn_1-x-y(OH)₂Preparing a nickel, cobalt and manganese mixed salt solution with a certain concentration, wherein x is more than or equal to 0.8<1，0.05≤y<0.2; preparing a complexing agent solution and a precipitator solution;

step S2, adding pure water, a complexing agent solution and a precipitator solution into a reaction kettle to prepare a reaction kettle bottom solution; the pH value of the reaction kettle bottom liquid is 11.0-13.0; introducing nitrogen into the reaction kettle, and introducing the prepared mixed salt solution of nickel, cobalt and manganese, the complexing agent solution and the precipitator solution into the reaction kettle in parallel flow to perform a nucleation reaction stage; the nucleation reaction stage keeps the pH value of the reaction system at 10.0-12.0; after 0.5-1.5h, reducing the pH value of the reaction system to 9.5-11.0, increasing the flow of the nickel, cobalt and manganese mixed salt solution added into the reaction kettle to perform a crystal growth stage, and stopping feeding when the granularity D50 of the reaction slurry reaches 10-18 mu m;

step S3, transferring the reaction slurry meeting the granularity requirement obtained by the reaction in the step S2 to an ageing tank for standing, and separating supernatant liquid and precipitate;

step S4, performing alkaline leaching treatment on the precipitate obtained in the step S3, washing, transferring the washed precipitate and the supernatant obtained in the step S3 to an aging tank, and adding alkali liquor to adjust the pH value for aging;

and S5, filtering, washing and drying to obtain the nickel-rich large-particle-size ternary precursor with the D50 of 10-18 microns, the sodium content of less than or equal to 100ppm and the sulfur content of less than or equal to 800 ppm.

2. The method of claim 1, wherein the salt for preparing the mixed salt solution of nickel, cobalt and manganese in step S1 is a sulfate of nickel, cobalt and manganese; the total metal ion concentration in the nickel, cobalt and manganese mixed salt solution is 1.0-5.0 mol/L; the mass fraction of the complexing agent solution is 15-30%; the mass fraction of the precipitant solution is 20-35%.

3. The method according to claim 1, wherein the reaction temperature in the nucleation stage and the reaction temperature in the crystal growth stage in step S2 are both 40 to 70 ℃, and the ammonia concentration of the reaction system is 2 to 15 g/L.

4. The method according to claim 1, wherein in the step of lowering the pH of the reaction system to 9.5 to 11.0 in the step S2, the rate of lowering the pH is not more than 0.5 per hour.

5. The method of claim 1, wherein the flow rate of the mixed salt of nickel, cobalt and manganese in the nucleation stage of step S2 is 20-60 ml/min.

6. The method according to claim 1 or 5, wherein the flow rate of the nickel, cobalt, manganese mixed salt solution in the crystal growth stage of step S2 is increased by 1 to 5 times.

7. The method of claim 6, wherein the flow rate of the nickel, cobalt, manganese mixed salt solution increased each time is 20-100% of the previous flow rate.

8. The preparation method according to claim 1, wherein the alkali solution used in the alkali leaching treatment in step S4 is one or more of sodium hydroxide, sodium bicarbonate and sodium carbonate solution, the mass fraction of the alkali solution is 2-10%, the alkali leaching temperature is 50-80 ℃, and the alkali leaching time is 30-60 min.

9. The method according to claim 1, wherein the aging process parameters in step S4 are: the stirring linear velocity is 1-3 m/s, the aging temperature is 55-70 ℃, the aging pH value is 10.5-11.5, and the aging time is 12-48 h.

10. The method according to claim 1, wherein in the step S5, washing is performed with pure water, and the pH at the end of washing is 8.0 to 9.0; controlling the water content of the material to be below 20% after dehydration; when drying, the drying temperature is 90-150 ℃, and the water content of the dried material is 0.1-0.8%.

Technical Field

The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a preparation method of a nickel-rich large-particle-size ternary precursor with low sodium and sulfur impurity contents.

Background

The lithium ion battery has the advantages of environmental protection, high energy density, large output power, high charging efficiency, excellent cycle performance, no memory effect and the like, is taken as the first choice of a green environment-friendly battery, and plays an important role in realizing the carbon peak-reaching carbon neutralization strategic target. High energy and high density are important directions for the development of future lithium ion batteries, and high nickel lithium ion batteries are favored in the application field of power batteries due to higher theoretical unit gram capacity. The ternary cathode material is a key material of the lithium ion battery, the core physical and chemical properties of the ternary cathode material are directly determined by the ternary precursor, and the primary particle morphology, the internal structure and the impurity content of the precursor have a profound influence on the cathode material.

At present, the industrially mature ternary precursor preparation process generally adopts a coprecipitation method, the used metal salt raw material is mostly sulfate, and the precipitator is sodium hydroxideAnd (3) solution. In the coprecipitation reaction process, after complexing of a sulfate solution and an ammonia water solution, the sulfate solution and a sodium hydroxide solution are subjected to precipitation reaction to generate primary particles, the primary particles are agglomerated into sphere-like secondary particles by controlling the conditions of temperature, pH value, stirring speed, feeding flow and the like in the coprecipitation reaction process, the secondary particles grow up gradually along with the further precipitation reaction, and a large amount of Na can be generated in the synthesis reaction⁺And SO₄ ^2- Some of these impurity elements are adsorbed and wrapped inside the grains continuously during the secondary grain growth process. If the impurity ions are not removed in the preparation process of the precursor, the impurity ions can still be continuously stored in the subsequent sintering process of the anode material, and the cycle and the capacity performance of the anode material are greatly influenced.

For removing sodium and sulfur impurities in the precursor, the method of hot alkali and hot pure water step by step washing is mostly adopted in industry. The precursor with relatively small particle size has relatively less adsorbed impurities, and sodium-sulfur impurities adsorbed on the surface and in the particles can be removed through a washing process, so that the existing small-particle-size product can reach the levels of Na being less than or equal to 50ppm and S being less than or equal to 600ppm, while the large-particle-size precursor has more impurity adsorption amount in the interior, and the impurities in the particles are difficult to remove through washing, and the impurity level is mostly about Na200ppm and S1500 ppm. Patent document No. CN107459069B discloses a method for reducing sulfur content in nickel-cobalt-aluminum precursor, which is to remove mother liquor from the prepared nickel-cobalt-aluminum precursor slurry, transfer the slurry to a washing kettle with a stirrer, add alkali liquor and keep stirring for a certain number of times of slurry washing, wherein slurry stirring in the washing kettle adopts three layers of stirring slurry, and the lowest layer is a propeller. The patent document with publication number CN112591808A discloses that the removal of sodium-sulfur impurities from the precursor is achieved by continuously replacing the mother liquor during the synthesis reaction to reduce the impurity content in the solution in the reaction kettle through multiple steps of 'seed preparation-seed growth-stopping reaction-increasing pH-solution replacement-starting reaction-particle growth to a target value-stopping reaction-increasing pH-solution replacement-filter pressing washing-drying and demagnetizing', but the method only reduces the impurities in the supernatantContent, and not effective in reducing Na contained in the interior of the precursor⁺And SO₄ ^2- Moreover, the mother liquor to be replaced contains a large amount of free nickel, and there is a problem that the reaction equilibrium is disturbed to lower the crystallinity.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to solve the technical problem of providing a method for preparing a nickel-rich large-particle-size ternary precursor with low sodium and sulfur contents.

In order to solve the technical problems, the invention adopts the following technical scheme:

the preparation method of the nickel-rich large-particle-size ternary precursor with low sodium and sulfur contents comprises the following steps of:

step S1, according to molecular formula Ni_xCo_yMn_1-x-y(OH)₂Preparing a nickel, cobalt and manganese mixed salt solution with a certain concentration, wherein x is more than or equal to 0.8<1，0.05≤y<0.2; preparing a complexing agent solution and a precipitator solution;

step S2, adding pure water, a complexing agent solution and a precipitator solution into a reaction kettle to prepare a reaction kettle bottom solution; the pH value of the reaction kettle bottom liquid is 11.0-13.0; introducing nitrogen into the reaction kettle, and introducing the prepared mixed salt solution of nickel, cobalt and manganese, the complexing agent solution and the precipitator solution into the reaction kettle in parallel flow to perform a nucleation reaction stage; the nucleation reaction stage keeps the pH value of the reaction system at 10.0-12.0; after 0.5-1.5h, reducing the pH value of the reaction system to 9.5-11.0, increasing the flow of the nickel, cobalt and manganese mixed salt solution added into the reaction kettle to perform a crystal growth stage, and stopping feeding when the granularity D50 of the reaction slurry reaches 10-18 mu m;

step S3, transferring the reaction slurry meeting the granularity requirement obtained by the reaction in the step S2 to an ageing tank for standing, and separating supernatant liquid and precipitate;

step S4, performing alkaline leaching treatment on the precipitate obtained in the step S3, washing, transferring the washed precipitate and the supernatant obtained in the step S3 to an aging tank, and adding alkali liquor to adjust the pH value for aging;

and step S5, filtering, washing and drying to obtain the nickel-rich large-particle-size ternary precursor with low sodium and sulfur contents.

The nickel-rich large-particle-size ternary precursor prepared by the method is a spherical precursor with primary particles agglomerated into secondary particles, D50 is 10-18 mu m, the particle size distribution is concentrated, an inner core and an outer shell are arranged, the outer shell is radial, the content of Na impurities is less than or equal to 100ppm, and the content of S impurities is less than or equal to 800 ppm.

Further, in the above preparation method, the salt of the mixed salt solution of nickel, cobalt and manganese prepared in step S1 is a sulfate of nickel, cobalt and manganese; the total metal ion concentration in the nickel, cobalt and manganese mixed salt solution is 1.0-5.0 mol/L; the mass fraction of the complexing agent solution is 15-30%; the mass fraction of the precipitant solution is 20-35%.

Further, the precipitator is sodium hydroxide, and the complexing agent is ammonia water.

Further, in the preparation method, the reaction temperature of the nucleation stage and the crystal growth stage in the step S2 is 40-70 ℃, and the ammonia water concentration of the reaction system is maintained at 2-15 g/L.

Further, in the above preparation method, in the process of reducing the pH value of the reaction system to 9.5 to 11.0 in step S2, the reduction rate of the pH value is not more than 0.5 per hour.

Further, in the above preparation method, the number of times of increasing the flow rate of the nickel, cobalt, and manganese mixed salt in the crystal growth stage in step S2 is 1 to 5 times. Furthermore, the flow rate of the nickel, cobalt and manganese mixed salt solution increased each time is 20-100% of the previous flow rate.

Further, in the preparation method, the flow rate of the nickel, cobalt and manganese mixed salt in the nucleation stage in the step S2 is 20-60 ml/min.

Further, in the preparation method, the alkaline solution used in the alkaline leaching treatment in the step S4 is one or more of sodium hydroxide, sodium bicarbonate and sodium carbonate solution, the mass fraction of the alkaline solution is 2-10%, the alkaline leaching temperature is 50-80 ℃, and the alkaline leaching time is 30-60 min.

Further, in the above preparation method, the aging process parameters in step S4 are: the stirring linear velocity is 1-3 m/s, the aging temperature is 55-70 ℃, the aging pH value is 10.5-11.5, and the aging time is 12-48 h.

Further, in the above preparation method, in the step S5, washing is performed with pure water at the time of washing, and the pH value at the end of washing is 8.0 to 9.0; controlling the water content of the material to be below 20% after dehydration; when drying, the drying temperature is 90-150 ℃, and the water content of the dried material is 0.1-0.8%.

In the reaction process of step S2, the nucleation and crystal growth stages are switched by controlling the pH reduction rate and the pH reduction amplitude, and loose aggregates of fine particles are formed in the nucleation stage to serve as cores. After the pH value is reduced to the target range of 9.5-11.0, the precursor starts to be converted into a crystal growth stage, subsequently newly generated precipitates grow on original secondary particles to further form a layer of shell, and the size growth rate of the secondary particles is ensured by regulating the flow of the metal salt for multiple times, so that the shell of the precursor presents a radial shape.

The precursor prepared in the step S2 has radial cracks from the particle surface to the inner core, and the particle shell is radial, so that a channel is provided for removing impurity ions in the washing process, and Na in the particles⁺And SO₄ ^2- Are effectively removed.

In the aging process of step S4, the supernatant is mixed with the washed precursor, and a certain amount of alkali solution is introduced to carry out an aging reaction, so that small particles in the mother solution are dissolved and large particles grow, cracks in particles on the surface of the precursor are repaired, and the precursor is sintered into a positive electrode material by lithium mixing without cracking.

In addition, in the preparation method, the precursor is washed for the second time, the water consumption for washing is less due to the structural particularity of the precursor during the first washing, sodium-sulfur impurities newly introduced in the aging reaction after the first washing are less, and only a small amount of water is needed for the second washing.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention provides a nickel-rich large-particle-size particle IIIThe preparation method of the precursor can effectively reduce Na in the interior and on the surface of the precursor material⁺And SO₄ ^2- The prepared precursor with large particle size and Na content of less than or equal to 100ppm and S content of less than or equal to 800ppm has impurity content far lower than that of the prior similar products and high product quality.

(2) According to the invention, in the processes of adjusting the structure of the precursor and reducing the impurity content of the product through cracking-washing-repairing, the mother liquor filtered in the reaction process is utilized, so that the secondary utilization of materials is realized, and the economy is better.

(3) The technical scheme provided by the invention does not introduce any other materials and equipment, realizes the preparation of the large-particle-size nickelic core-shell structure ternary precursor through flow adjustment and aging process optimization, and is suitable for the current intermittent process and large-scale production.

Drawings

FIG. 1 shows Ni with a large particle size obtained in step S2 in example 1 of the present invention_0.9Co_0.05Mn_0.05(OH)₂Scanning electron micrographs of the precursor.

FIG. 2 shows Ni with large particle size finally prepared in example 1 of the present invention_0.9Co_0.05Mn_0.05(OH)₂Scanning electron micrographs of the precursor.

FIG. 3 shows Ni with large particle size finally prepared in example 1 of the present invention_0.9Co_0.05Mn_0.05(OH)₂Scanning electron microscope image of the section of the precursor.

FIG. 4 shows LiNi, a positive electrode material prepared in example 1 of the present invention_0.9Co_0.05Mn_0.05O₂Scanning electron micrograph (c).

Detailed Description

In order to make the objects, technical solutions and advantageous effects of the present invention more clearly apparent, the present invention will be described in further detail with reference to the accompanying drawings and the detailed description. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Example 1

The embodiment comprises the following specific steps:

step S1, according to molecular formula Ni_0.9Co_0.05Mn_0.05(OH)₂Preparing a nickel, cobalt and manganese mixed salt solution with the total metal ion concentration of 2mol/L according to the proportion of each metal ion; preparing a sodium hydroxide solution with the mass fraction of 32%; preparing an ammonia water solution with the mass fraction of 20%.

Step S2, adding pure water, an ammonia water solution and a sodium hydroxide solution into a 100L reaction kettle, adjusting the pH value to 11.50, adjusting the concentration of the ammonia water to 10.0g/L, introducing nitrogen for protection, injecting a nickel, cobalt and manganese mixed salt solution into the reaction kettle at the flow rate of 40ml/min during the nucleation stage reaction, introducing a complexing agent solution and a precipitator solution, maintaining the pH value of the reaction system to 11.50 +/-0.05, maintaining the concentration of the ammonia water of the reaction system to 10.0 +/-0.5 g/L, controlling the reaction temperature to 65 ℃, reducing the pH value of the reaction system to 10.60 at the rate of reducing the pH value of 0.30 per hour after 1h, controlling the pH value to be in the range of 10.60 +/-0.05 for crystal growth stage reaction, increasing the flow rate of a nickel, cobalt and manganese metal salt solution to 80ml/min after the reaction slurry D50-7 mu m, increasing the flow rate of the nickel, cobalt and manganese mixed salt solution to 120ml/min after the reaction slurry D50 is 11 mu m, after the D50 reaction reaches 13 μm, the flow rate of the mixed salt solution of nickel, cobalt and manganese is increased to 160ml/min, and when the reaction slurry D50 reaches 15 μm, the feeding is stopped.

And step S3, transferring the slurry obtained in the step S2 to an aging tank, standing and precipitating, extracting supernatant A, sealing and storing, adding a sodium hydroxide solution with the mass fraction of 5% into the residual slurry, and performing alkaline leaching at the temperature of 80 ℃ for 60 min.

And S4, pumping the material obtained in the step S3 into a centrifuge, washing the material with pure water until the pH value is less than 9.5, then spin-drying the material, transferring the material and the supernatant A obtained in the step S3 into an aging tank, adding a sodium hydroxide solution to adjust the pH value to 11.00 +/-0.03, and aging the material at the stirring linear speed of 1.5m/S and the aging temperature of 65 ℃ for 12 hours.

And step S5, pumping the aged material into a centrifuge, washing the material with pure water until the pH value is less than 9.5, then spin-drying the material, and drying the material at 100 ℃ to obtain the low-impurity nickel-rich large-particle-size ternary precursor with D50=14.9 mu m, the Na content of 78ppm and the S content of 720 ppm.

FIG. 1 shows Ni with a large particle size obtained in step S2 in example 1 of the present invention_0.9Co_0.05Mn_0.05(OH)₂The scanning electron microscope image of the precursor shows that the precursor has cracks.

FIG. 2 shows Ni with a large particle size in the final product obtained in example 1 of the present invention_0.9Co_0.05Mn_0.05(OH)₂And (5) repairing the cracks by scanning electron microscopy of the precursor.

FIG. 3 shows Ni with a large particle size in the final product obtained in example 1 of the present invention_0.9Co_0.05Mn_0.05(OH)₂The sectional electron microscope image of the precursor shows that the precursor has a core and a shell, and the shell is radial.

FIG. 4 shows Ni in the final product of this example_0.9Co_0.05Mn_0.05(OH)₂LiNi as anode material after sintering of precursor mixed lithium_0.9Co_0.05Mn_0.05O₂Scanning electron micrograph (c). As can be seen from the figure, the positive electrode material did not have a cracking phenomenon.

Generally speaking, the surface of the precursor after the synthesis reaction has certain cracks, the cracks can be repaired after the aging treatment, the cracking phenomenon does not occur after the lithium mixed is sintered into the anode material, and meanwhile, the precursor has an inner core and an outer shell, and the outer shell is in an obvious radial shape.

Example 2

The embodiment comprises the following steps:

step S1, according to molecular formula Ni_0.86Co_0.10Mn_0.04(OH)₂Preparing a nickel, cobalt and manganese mixed salt solution with the total metal ion concentration of 2mol/L according to the proportion of the medium metal ions, preparing a sodium hydroxide solution with the mass fraction of 28%, and preparing an ammonia water solution with the mass fraction of 25%;

step S2, adding pure water, an ammonia water solution and a sodium hydroxide solution into a 100L reaction kettle, adjusting the pH value to 11.70, adjusting the ammonia water concentration to 7.0g/L, introducing nitrogen for protection, injecting a nickel, cobalt and manganese mixed salt solution into the reaction kettle at the flow rate of 30ml/min in the nucleation stage reaction process, introducing a complexing agent solution and a precipitator solution, maintaining the pH value of the reaction system at 11.70 +/-0.05, maintaining the ammonia water concentration of the reaction system at 7.0 +/-0.5 g/L, controlling the reaction temperature at 60 ℃, reducing the pH value of the reaction system to 10.30 at the rate of reducing the pH value by 0.40 per hour after 1.5h, performing crystal growth stage reaction at the pH value of 10.50 +/-0.05, increasing the flow rate of the nickel, cobalt and manganese mixed salt solution to 40ml/min after D50 is reacted to 5 mu m, increasing the flow rate of the nickel, cobalt and manganese metal salt solution to 80ml/min after D50 is reacted to 8 mu m, when reaction slurry D50 reached 10.5 μm, the feeding was stopped;

step S3, transferring the obtained slurry to an aging tank, standing for precipitation, extracting supernatant B, sealing and storing, adding 8% by mass of sodium hydroxide solution into the residual slurry, and maintaining the temperature at 80 ℃ for alkaline leaching for 60 min;

step S4, pumping the material obtained in the step S3 into a centrifuge, washing the material by pure water until the pH value is less than 9.5, then spin-drying the material, transferring the material and the supernatant B obtained in the step S3 into an aging tank, adding a sodium hydroxide solution to adjust the pH value to 10.80 +/-0.03, maintaining the stirring linear velocity at 3.0m/S and the aging temperature at 60 ℃, and aging for 24 hours;

and step S5, pumping the aged material into a centrifuge, washing the material by using pure water until the pH value is less than 9.5, spin-drying the material, and drying the material at 100 ℃ to obtain the low-impurity nickel-rich large-particle-size ternary precursor with D50=10.5 mu m, the Na content of 55ppm and the S content of 640 ppm.

Example 3

The embodiment comprises the following steps:

step S1, according to molecular formula Ni_0.9Co_0.05Mn_0.05(OH)₂Preparing a nickel, cobalt and manganese mixed salt solution with the total metal ion concentration of 2mol/L according to the proportion of the medium metal ions, preparing a sodium hydroxide solution with the mass fraction of 20%, and preparing an ammonia water solution with the mass fraction of 20%;

step S2, adding pure water, an ammonia water solution and a sodium hydroxide solution into a 100L reaction kettle, adjusting the pH value to 11.30, adjusting the ammonia water concentration to 5.0g/L, and introducing nitrogen for protection; in the reaction process of the nucleation stage, injecting a nickel, cobalt and manganese mixed salt solution into a reaction kettle at the flow rate of 50ml/min, introducing a complexing agent solution and a precipitator solution, maintaining the pH value of a reaction system to be 11.30 +/-0.05, maintaining the ammonia water concentration of the reaction system to be 5.0 +/-0.5 g/L, controlling the reaction temperature to be 70 ℃, reducing the pH value of the reaction system to 10.30 at the rate of reducing the pH value of 0.30 per hour after 1h, controlling the reaction to be 10.30 +/-0.05 to carry out crystal growth stage reaction, increasing the flow rate of the nickel, cobalt and manganese mixed salt solution to be 80ml/min after D50 reacts to be 7 mu m, and stopping feeding when the reaction slurry D50 reaches 10.5 mu m;

step S3, transferring the obtained slurry to an aging tank, standing for precipitation, extracting supernatant C, sealing and storing, adding a sodium hydroxide solution with the mass fraction of 5% into the residual slurry, and maintaining the temperature at 80 ℃ for alkaline leaching for 60 min;

step S4, pumping the material obtained in the step S3 into a centrifuge, washing the material by pure water until the pH value is less than 9.5, then spin-drying the material and the clear liquid C obtained in the step S3 to an aging tank, adding a sodium hydroxide solution to adjust the pH value to 11.00 +/-0.03, maintaining the stirring linear speed at 3.0m/S and the aging temperature at 70 ℃, and aging for 48 hours;

and step S5, pumping the aged material into a centrifuge, washing the material by using pure water until the pH value is less than 9.5, spin-drying the material, and drying the material at 100 ℃ to obtain the low-impurity nickel-rich large-particle-size ternary precursor with D50=10.5 mu m, the Na content of 88ppm and the S content of 766 ppm.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.