CN111943278A

CN111943278A - Preparation method of ternary precursor with narrow particle size distribution

Info

Publication number: CN111943278A
Application number: CN202010690386.9A
Authority: CN
Inventors: 罗爱平; 吴芳
Original assignee: Fangyuan Environmental Protection Ltd
Current assignee: Fangyuan Environmental Protection Ltd
Priority date: 2020-07-17
Filing date: 2020-07-17
Publication date: 2020-11-17
Anticipated expiration: 2040-07-17
Also published as: CN111943278B

Abstract

The invention provides a preparation method of a ternary precursor with narrow particle size distribution, which comprises the following steps of: preparing a mixed solution A of nickel ions, cobalt ions and M ions, a first strong alkaline solution B1 and a first complexing agent solution C1 according to a preset molar ratio; preparing a base solution: adding pure water, a second strong alkaline solution B2 and a second complexing agent solution C2 into a reaction device; nucleation and growth phases: after nucleation is finished, the mixed solution A, the first strong alkaline solution B1 and the first complexing agent solution C1 are continuously added into the reaction device at the same time according to a preset proportion, crystal nuclei continue to grow, during the process, when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device, concentration treatment is carried out, the filtered liquid is discharged out of the reaction device, and the crystal nuclei continue to grow in the reaction device until the crystal nuclei grow to the target particle size.

Description

Preparation method of ternary precursor with narrow particle size distribution

Technical Field

The invention belongs to the field of new energy materials, and particularly relates to a preparation method of a ternary precursor with narrow particle size distribution.

Background

The lithium ion battery is rapidly developed in the application market of the electric automobile, the lithium ion battery with high specific energy density is developed, the cost of the power battery is reduced to improve the competitiveness of the new energy automobile on the fuel automobile, and the current urgent need is met. The ternary positive electrode material has higher reversible capacity and voltage platform than the lithium iron phosphate material, has obvious cost advantage than the lithium cobaltate material, and becomes the main selection scheme of the current electric passenger vehicle.

In the process of charging and discharging of the battery, too small particles in the ternary cathode material have larger contact area with the electrolyte, and lithium ions have short migration distance in the particles, so that overcharge and overdischarge are easily caused in the normal charging and discharging process, and on the contrary, too large particles are not sufficient in charging and discharging, so that the capacity exertion of the battery is easily lower than expected. The ternary material with narrow particle size distribution can reduce the safety problem and the battery failure problem which are possibly caused by overcharge and overdischarge, is beneficial to reducing the polarization of the battery, improves the safety of the battery, can also obviously improve the pulping stability and the coating uniformity, and further improves the cycle life of the battery. The ternary precursor is a key material for producing the ternary cathode, the ternary cathode material is prepared by mixing and sintering the ternary precursor with a lithium source, and the particle size distribution of the ternary precursor directly determines the particle size distribution of the ternary cathode material, so that the preparation of the ternary precursor with narrow particle size distribution has very important significance for improving the comprehensive performance of the battery.

At present, the general method is a two-step method in the preparation process of the ternary precursor. As disclosed in CN 110550667A: after reaction in the seed crystal kettle, pumping the mixture into a plurality of reaction kettles by using a pump, separately reacting in the reaction kettles, overflowing the liquid in the reaction kettles to a corresponding intermediate tank when the liquid reaches an overflow port, pumping the liquid into a concentration tank from the intermediate tank by using a pump, wherein the aperture of a filter element in the concentration tank is 0.01-0.5um, filtering solid particles in the slurry, discharging clear liquid from a clear outlet, refluxing the filtered material into the reaction kettles to enable the solid content in the reaction kettles to be increased to 900g/L (300) and the particle size to reach a target value, finishing the reaction, carrying out solid-liquid separation, washing the anode material precursor obtained by the solid-liquid separation by using deionized water, and finally carrying out drying treatment to prepare the precursor of the lithium ion battery. As also disclosed in CN 110600683A: evenly add metal salt solution, liquid caustic soda, aqueous ammonia in the reation kettle through the measuring pump, flow into the ageing groove through the overflow mouth after reation kettle material liquid is full, during thick liquids are squeezed into the concentrator through pneumatic diaphragm pump in the ageing groove, the concentrator discharges partial clear liquid through inside filter core pipeline, the thick liquid of formation flows back to reation kettle in, whole in-process ageing groove liquid level keeps the relatively stable value, the material that is higher than stable liquid level is through pneumatic diaphragm pump pumping toward centrifuge washing.

After the overflow liquid is settled by adopting modes of a middle tank, a concentration tank and the like, the overflow liquid is conveyed to the reaction kettle by adopting a pump to grow continuously, on one hand, partial ternary crystal nucleus particles are extruded mutually when conveyed in a pump pipe, and the surface appearance of the precursor is damaged or the sphere of the precursor is crushed; on the other hand, after the ternary crystal nucleus particles entering the intermediate tank or the concentration tank leave the initial reaction system, the ternary crystal nucleus particles enter the reaction kettle again for reaction, so that the growth is not uniform, the obtained ternary precursor has non-uniform particle size, and the particle size distribution of the ternary precursor material directly influences the service life and other key performances of the battery.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, it is an object of the present invention to provide a ternary precursor with a narrow particle size distribution. The second purpose of the invention is to provide a preparation method of the ternary precursor with narrow particle size distribution. The third purpose of the invention is to provide a reaction device for preparing the ternary precursor with narrow particle size distribution, which has accurate control on the particle size distribution, is suitable for an intermittent continuous production process, and can realize continuous production of the ternary precursor with narrow particle size distribution.

In the present invention, the ternary precursor having a narrow particle size distribution means that the concentration of the particle size distribution is high and the particle size distribution range is narrow, and those skilled in the art can understand and clearly understand the meaning. For example, some embodiments of the present invention refer to laser particle size testing with only one peak and peak bulk density of 15% and above.

The technical scheme adopted by the invention is as follows:

in a first aspect, the invention provides a ternary precursor with narrow particle size distribution, wherein the chemical composition of the ternary precursor is Ni_xCo_yM_1-x-y(OH)₂Wherein x is more than or equal to 0.40 and less than or equal to 0.98, y is more than or equal to 0.02 and less than or equal to 0.3, and x + y is less than 1.

In some embodiments of the invention, the D50 of the ternary precursor is between 3 and 18 μm, and the particle size satisfies 0.15 ≦ (D90-D10)/D50 ≦ 1.1. In other embodiments of the invention, the D50 of the ternary precursor is between 3 and 18 μm, and the particle size satisfies 0.75 ≦ (D90-D10)/D50 ≦ 1.0.

In some embodiments of the invention, M is a mixture of one or more of Mn, a1, Zr, Ti.

In some embodiments of the invention, the M is one of Mn or Al.

In some embodiments of the invention, the chemical composition is Ni_xCo_yM_1-x-y(OH)₂The ternary precursor is obtained according to the following preparation method:

preparing a solution, namely preparing a mixed solution A of nickel ions, cobalt ions and M ions, a first strong alkaline solution B1 and a first complexing agent solution C1 according to a preset molar ratio;

preparing a base solution: adding pure water, a second strong alkaline solution B2 and a second complexing agent solution C2 into a reaction device;

a nucleation stage: adding the mixed solution A, the first strong alkaline solution B1 and the first complexing agent solution C1 into a reaction device at the same time according to a preset proportion, and fully reacting to form crystal nuclei;

and (3) growth stage: after nucleation is finished, continuously adding the mixed solution A, the first strong alkaline solution B1 and the first complexing agent solution C1 into a reaction device at the same time according to a preset proportion, so that crystal nuclei continue to grow, and during the period, when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device, carrying out concentration treatment, so that filtered liquid is discharged out of the reaction device, and the crystal nuclei continue to grow in the reaction device until the crystal nuclei grow to a target particle size;

and (3) post-treatment stage: and when the crystal nucleus in the reaction device grows to the target particle size, stopping feeding, and performing solid-liquid separation, pure water washing and drying to obtain the ternary precursor with narrow particle size distribution.

In a second aspect, the invention also provides a preparation method of the ternary precursor with narrow particle size distribution, which comprises the following steps,

preparing a solution: preparing a mixed solution A of nickel ions, cobalt ions and M ions, a first strong alkaline solution B1 and a first complexing agent solution C1 according to a preset molar ratio;

In some embodiments of the present invention, it is preferable to perform the concentration treatment when the solution in the reaction device reaches the full level of the reaction device, so as to improve the volumetric utilization efficiency of the reaction device and the production efficiency.

In some embodiments of the present invention, the molar ratio of the nickel ions, the cobalt ions, and the M ions in the mixed solution a may be adjusted according to actual needs, which is not specifically limited in this application. Specifically, in some embodiments of the present invention, the step of simultaneously adding the mixed solution a, the first strongly basic solution B1 and the first complexing agent solution C1 in a predetermined ratio into a reaction device in the step nucleation stage means that the mixed solution a, the first strongly basic solution B1 and the first complexing agent solution C1 are continuously added into the reaction device at a predetermined speed simultaneously. In an embodiment of the present invention, the first complexing agent is ammonia water, and the ammonia concentration of the ammonia water is 1.0 to 12.0 mol/L. The time for continuously adding the ammonia water can be controlled between 1 and 5 hours. In other embodiments of the present invention, the first complexing agent may also be at least one of ammonium sulfate, ethylenediaminetetraacetic acid (EDTA), sodium bicarbonate, and oxalic acid. In the step growth stage, after nucleation is finished, continuously adding the mixed solution a, the first strongly alkaline solution B1 and the first complexing agent solution C1 into a reaction device at the same time according to a preset ratio, namely, continuously adding the mixed solution a, the first strongly alkaline solution B1 and the first complexing agent solution C1 into the reaction device at the same time at a preset speed so as to grow crystal nuclei. And (3) with the continuous addition of the mixed solution A, the first strong alkaline solution B1 and the first complexing agent solution C1, the volume of the total solution in the reaction device is continuously increased, when the liquid level of the reaction device is full, the concentration device in the reaction device is started, the filtered solution is discharged out of the reaction device, and the crystal nucleus is continuously remained in the reaction device for growing until the crystal nucleus grows to the target particle size. And then stopping feeding, and carrying out solid-liquid separation, pure water washing and drying on the precursor solution in the reaction device to obtain the ternary precursor with narrow particle size distribution.

In some embodiments of the invention, the number of times of washing with pure water is 1-5, the drying temperature is 110-150 ℃, and the drying time is 1-10 hours. Particularly, in the invention, after the drying step, the post-treatment processes such as screening, demagnetizing and the like can be carried out, so that partial caking or introduced impurities caused in the preceding process steps such as drying and the like are reduced, and the product is packaged and put in storage.

In some embodiments of the invention, the ternary precursor with narrow particle size distribution has a target particle size D50 of between 3 and 18 (. + -. 0.5) μm.

The problem that in the prior art, after overflow liquid is settled by adopting a middle tank, a concentration tank and the like, the overflow liquid is conveyed to a reaction kettle by a pump to grow continuously is avoided, and on one hand, partial ternary crystal nucleus particles are extruded mutually when conveyed in a pump pipe, so that the surface appearance of a precursor is damaged or a precursor sphere is crushed; on the other hand, after the ternary crystal nucleus particles entering the intermediate tank or the concentration tank leave the initial reaction system, the ternary crystal nucleus particles enter the reaction kettle again for reaction, so that the growth is not uniform, the obtained ternary precursor has nonuniform particle size, and the ternary precursor with good particle size growth uniformity is obtained.

In some embodiments of the present invention, the first strongly basic solution B1 is at least one of sodium hydroxide and potassium hydroxide, and the second strongly basic solution B2 is at least one of sodium hydroxide and potassium hydroxide. It is understood that the first strongly basic solution B1 may or may not be the same as the second strongly basic solution B2. Specifically, in some embodiments of the present invention, the first strongly basic solution B1 is sodium hydroxide and the second strongly basic solution B2 is sodium hydroxide.

In some embodiments of the present invention, the concentration of hydroxide in the first strongly basic solution B1 and the second strongly basic solution B2 is 1.0-12.0 mol/L. It is understood that the hydroxide concentration of the first strongly basic solution B1 may or may not be the same as the hydroxide concentration of the second strongly basic solution B2. Specifically, in some embodiments of the present invention, the concentration of hydroxide in the first strongly basic solution B1 and the second strongly basic solution B2 is 3.0-10.0 mol/L.

The second complexing agent C2 is at least one of ammonia water, ammonium sulfate, EDTA, sodium bicarbonate and oxalic acid. It is to be understood that the second complexing agent may or may not be the same as the first complexing agent. Specifically, in an embodiment of the present invention, the second complexing agent is ammonia water. The ammonia radical concentration of the ammonia water is 1.0-12.0 mol/L.

When the water-soluble inorganic salt does not contain complexing agents such as ammonia water and the like, the addition of a precipitator can cause severe nucleation and growth, and form loose secondary particles with low tap density. Thus, it is difficult to grow a precursor having a uniform particle size and a high tap density. When the ammonia is selected as the complexing agent, the added metal ions can be effectively complexed, the disturbance of the addition of the raw materials to the balance of the precipitate is relieved, the supersaturation degree of the precipitate in the solution is controlled, the nucleation and growth speeds can be reduced, the crystal can slowly grow, and the regulation and the control are convenient. Certainly, the ammonia water concentration is not as high as possible, and besides cost and pollution factors, the specific surface area and tap density can show the following change rules along with the change of the ammonia water concentration: when the concentration of the ammonia water is low, the amount of complex metal ions is small, higher solution supersaturation is brought, the growth speed of the precursor is too high, and the primary particle size of the precursor is small, the number of gaps is large, the particle appearance is loose and porous, and the compactness is poor. When the concentration of ammonia water is too high, the primary particles grow large, and the coarse crystal grains increase the number of gaps again, resulting in an increase in the specific surface area. In addition, ammonia water is used as a reaction complexing agent, the purpose of controlling free metal ions is achieved by complexing metal ions, the proportion of nickel, cobalt and manganese of a precursor deviates from a design value due to excessive or excessively low dosage of the complexing agent, the complexed metal ions are discharged along with supernatant, waste is caused, and meanwhile, more difficulty is caused in subsequent wastewater treatment, so that ternary precursors with different compositions are prepared, and the required ammonia water concentration is different.

In some embodiments of the invention, the reaction apparatus is a reaction vessel. Specifically, the reactor is a circulating flux reaction kettle, and the circulating flux of the circulating flux reaction kettle is between 200 and 3000L/h. Further, in some embodiments of the present invention, the reaction apparatus has an appropriate amount of a base solution inside before the mixed solution a is added.

In some embodiments of the present invention, the liquid level of the bottom liquid in the reaction device is slightly higher than the height of the feed inlet, for example, 1-10 cm higher. In other words, the feed inlet of the reaction device is positioned below the liquid level of the bottom liquid in the reaction device, so that the precursor solution added in the reaction device can be rapidly dispersed. In other embodiments of the present invention, the liquid level of the bottom liquid in the reaction apparatus may be lower than the height of the feed port. Of course, in the present invention, whether the feed inlet is below the liquid level of the bottom liquid or not can be realized, and the skilled person can select the feed inlet according to the actual needs.

In some embodiments of the present invention, the total metal concentration in the mixed solution A is 0.5-2.5 mol/L. In other embodiments of the present invention, the total metal concentration in the mixed solution A is 1.0 to 2.5 mol/L. More specifically, in some embodiments of the present invention, the total metal concentration in the mixed solution A is 1.0 to 2.0 mol/L.

In some embodiments of the present invention, the pH of the base solution is 11.5 to 13.0, and the volume of the base solution is 0.2 to 0.5 of the full liquid level volume of the reaction apparatus.

In some embodiments of the invention, the molar concentration of the second complexing agent C2 in the base solution is 0.2-1.0 mol/L.

In some embodiments of the present invention, the reaction temperature in the nucleation stage is 40-80 ℃, the reaction time is 1-5 hours, and the reaction pH is 12.0-13.0. In some embodiments of the invention, the nucleation stage reaction temperature is 40-65 ℃.

In some embodiments of the present invention, the reaction temperature in the growth stage is 40 to 80 ℃, the reaction time is 10 to 100 hours, and the reaction pH is 10.5 to 12.0. In some embodiments of the invention, the nucleation stage reaction temperature is 40-65 ℃.

Different pH values have obvious influence on the nucleation speed and the growth speed of the crystal, and when the pH value is lower, the growth speed of the precursor particles is higher than the nucleation speed due to smaller supersaturation degree in the solution, so that the particles with better appearance are easy to obtain. Under the condition of high pH value, the supersaturation degree in the solution system is larger, the formation rate of crystal nucleus is very fast, and the growth rate of precursor particles is slower, so that a microcrystal structure with smaller particles is formed. Therefore, in the present invention, it is preferable to control the pH value in the nucleation stage to be 12.0 to 13.0 and the pH value in the growth stage to be 10.5 to 12.0.

In a third aspect, the invention also provides a reaction device of the ternary precursor with narrow particle size distribution, which comprises a reaction device body and a stirring device, wherein the reaction device body is provided with a feeding hole and a discharging hole; the concentration device is used for improving the concentration of the ternary precursor solution in the reaction device, and the concentration device is used for promoting the ternary precursor solution in the reaction device to react to generate the ternary precursor with narrow particle size distribution.

In some embodiments of the invention, the particle size D50 of the ternary precursor with narrow particle size distribution is between 3 and 18 μm, and satisfies 0.15 ≦ (D90-D10)/D50 ≦ 1.1.

In some embodiments of the invention, a reaction apparatus is used to produce the narrow particle size distribution ternary precursor having a chemical composition of Ni_xCo_yM_1-x-y(OH)₂Wherein x is more than or equal to 0.40 and less than or equal to 0.98, y is more than or equal to 0.02 and less than or equal to 0.3, and x + y is less than 1. Specifically, in some embodiments of the present invention, M is a mixture of one or more of Mn, a1, Zr, and Ti. In the present invention, when M is one of Mn, a1, Zr, and Ti, it is a ternary precursor. When M is a mixture of multiple Mn, A1, Zr and Ti, M is a multi-element precursor and is referred to as a ternary precursor in the invention.

In some embodiments of the invention, the bottom of the concentration device is located slightly below the full level line of the reaction device. Therefore, when the liquid level of the solution in the reaction device reaches the position of the full liquid level line, the concentration device is immediately started, precursor crystal nuclei in the reaction device are left for continuous reaction, the filtered solution is discharged out of the reaction device, and solution components in the reaction device can be kept in a relatively balanced environment, so that the ternary precursor with narrow particle size distribution is obtained.

In some embodiments of the present invention, specifically, the concentration device includes: the two ends of the fixing piece are respectively connected with the filtering piece and the reaction device body and used for fixing the filtering piece; one end of the filter element is connected with the fixing element, the other end far away from the end connected with the fixing element is connected with the filtered clear liquid discharge element, and when the ternary precursor solution in the reaction device body reaches a full liquid level line, the filter element is used for filtering the filtered clear liquid in the ternary precursor solution and improving the concentration of the ternary precursor solution in the reaction device body; one end of the clear liquid filtering and discharging piece is connected with the filtering piece, the other end far away from the end connected with the filtering piece is connected with the reaction device body, and the clear liquid filtering and discharging piece extends to the outside of the reaction device body; wherein, the fixing piece, the filter piece, the filtered liquid discharging piece and the reaction device body form a closed area.

In some embodiments of the invention, the filter element comprises at least one set of filter elements. In particular, in some embodiments of the invention, the filter element comprises one to ten unequal sets of filter elements. More specifically, the filter element includes one to five unequal sets of filter elements. In one embodiment of the invention, the filter element comprises a series of filter elements. In another embodiment of the invention, the filter pack includes five sets of filter elements. In yet another embodiment of the invention, the filter pack includes ten sets of filter elements. The number of the filter elements can be flexibly selected according to the reaction device and the size of the target granularity of the ternary precursor to be obtained. In addition, it should be noted that when the number of filter elements is too large, unnecessary reduction of the filtration efficiency and increase of the filtration cost are caused.

In some embodiments of the present invention, a pressure extraction device is further connected to a portion of the filtered liquid discharge member extending to the outside of the reaction device body, so as to change the filtering efficiency of the filter member. Generally, the filter element can realize that the filter liquor discharged after being filtered by the filter element is in dynamic balance with the volume of the ternary precursor solution simultaneously added into the reaction device. In another case, when the instantaneous volume of the solution of the ternary precursor added into the reaction device is larger than the filtered clear solution discharged after filtering by the filter element, the volume of the solution in the reaction device will be continuously increased, which may cause overflow on one hand and change of the reaction environment in the reaction device on the other hand, thereby affecting the particle size distribution of the ternary precursor. Therefore, at this time, an external pressure extraction device is required, positive pressure is formed inside and outside the filter element, the filtering efficiency is improved, and the volume of the filtered solution discharged after being filtered by the filter element in the reaction device and the volume of the ternary precursor solution simultaneously added into the reaction device are in instantaneous dynamic balance. It can be understood that, in the present invention, when the instantaneous volume of the ternary precursor solution added into the reaction device is smaller than the filtered clear solution discharged after being filtered by the filter element, on one hand, the filter element with smaller filter holes can be replaced, and on the other hand, the reverse pressure can be formed by the pressure extraction device, so as to reduce the filtering efficiency of the filter element, and realize the instantaneous dynamic balance between the discharged clear solution and the volume of the ternary precursor solution added into the reaction device body.

In some embodiments of the present invention, at least one valve is further disposed on the pressure extraction device, so as to adjust the pressure generated by the pressure extraction device, so that during filtering by the filter element of the concentration device, the filtered liquid discharged from the reaction device after filtering by the filter element is in instantaneous dynamic equilibrium with the volume of the ternary precursor solution simultaneously added into the reaction device more quickly and accurately.

In some embodiments of the present invention, at least one end of the filter element is connected to a filtered liquid collecting device, and the filtered liquid collecting device is connected to the filtered liquid discharging member through a connecting device, so that the filtered liquid can be smoothly discharged from the filtered liquid discharging member. It will be appreciated that in other embodiments of the invention, a filtrate collection device may be connected to each end of the filter element. From the practical effect, any end of the filter element is connected with a filtered liquid collecting device, filtered liquid in the filter element is collected, and the filtered liquid is smoothly discharged through being connected with the filtered liquid discharging piece.

In particular, in one embodiment of the present invention, the filtered liquid discharging member may also function as a fixing member, and when the filtered liquid collecting means is connected to both ends of the filter element in the filter member, it is preferable to fix the filter element by the filtered liquid discharging member. At this time, the concentration device has no fixing member, and both ends are fixed by the filtrate discharging member, respectively.

In some embodiments of the invention, the filtrate discharge and the filtrate collection device each have a hollow conduit. Specifically, the filtered liquid discharging member and the filtered liquid collecting device may have the same diameter of the hollow pipe. It can be understood that, in the present invention, the diameters of the hollow pipelines of the filtered liquid discharging member and the filtered liquid collecting device may also be different, and at this time, only the corresponding adapter needs to be arranged at the connection position of the hollow pipelines of the filtered liquid discharging member and the filtered liquid collecting device. In the present invention, the diameter of the hollow pipe of the filtered liquid discharging member and the diameter of the hollow pipe of the filtered liquid collecting device are the same, and the two parts can be connected by a flange, and it should be understood that other connection methods such as a screw connection, etc. capable of achieving a substantially sealed connection are all possible. Specifically, in the present invention, when the filtered liquid discharging member is connected to the hollow pipe of the filtered liquid collecting device by a flange, a sealing gasket is further provided to enhance the sealing effect between the filtered liquid discharging member and the hollow pipe of the filtered liquid collecting device. The sealing gasket is made of an elastic material, and specifically can be a silica gel gasket, a rubber gasket, a metal gasket (such as copper), a plastic gasket (such as polytetrafluoroethylene) or a graphite plate gasket. In the invention, the sealing washer is a silica gel washer.

In some embodiments of the invention, the pore size of the filter element is 0.05-1.0 μm. In some embodiments of the invention, the pore size of the filter element is 0.1-1.0 μm. Generally, when the volume of the solution in the reaction apparatus reaches the full level, the crystal nucleus volume is generally larger than 1.5 μm, so that the filter element with the pore diameter of 0.05-1.0 μm is selected.

In some embodiments of the present invention, when the ternary precursor solution in the reaction device reaches a full liquid level, the volume of the filtrate discharged after being filtered by the filter element and the volume of the ternary precursor solution simultaneously added into the reaction device are in dynamic equilibrium, so that the solution in the reaction device is in a relatively balanced chemical environment, which is beneficial to obtain the ternary precursor with narrow particle size distribution.

The invention has at least one of the following beneficial effects:

(1) the ternary precursor with narrow particle size distribution is provided, the particle size distribution concentration is very high, the particle size distribution range is narrow, the particle size is accurate and controllable, and the stability is good.

(2) The preparation method of the ternary precursor with narrow particle size distribution is simple to operate, high in automation degree, capable of directly reacting in a reaction kettle, free of kettle-by-kettle concentration and narrow in particle size distribution of the prepared ternary precursor.

(3) The reaction device for the ternary precursor with the narrow particle size distribution is suitable for continuous production operation, high in production efficiency, high in productivity and low in production cost, can be used for preparing the ternary precursor with the narrow particle size distribution, has very important significance for improving the safety performance, the cycle performance, the service life and the like of a battery, and effectively solves the problems of wide particle size distribution, poor cycle performance and the like of the ternary precursor in the current preparation method.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic flow chart of a preparation method of a ternary precursor with a narrow particle size distribution according to embodiment 1 of the present invention.

FIG. 2 is a schematic view of the structure of a reaction apparatus in accordance with embodiment 1 of the present invention.

Fig. 3 is a schematic view of a filter member in embodiment 1 of the present invention.

Fig. 4 is an SEM electron micrograph of the ternary precursor with a narrow particle size distribution prepared according to embodiment 1 of the present invention.

FIG. 5 is an SEM image of the ternary precursor prepared in comparative example 1 of the present invention.

Fig. 6 is an SEM electron micrograph of the ternary precursor with a narrow particle size distribution prepared according to embodiment 2 of the present invention.

Fig. 7 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 3 of the present invention.

FIG. 8 is an SEM image of the ternary precursor prepared in comparative example 2 of the present invention.

Fig. 9 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 4 of the present invention.

FIG. 10 is an SEM image of a ternary precursor prepared in comparative example 3 of the present invention.

Fig. 11 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 5 of the present invention.

FIG. 12 is an SEM image of a ternary precursor prepared in comparative example 4 of the present invention.

Fig. 13 is a particle size test chart of the ternary precursor with a narrow particle size distribution prepared in embodiment 1 of the present invention.

Fig. 14 is a particle size test chart of the ternary precursor prepared in comparative example 1 of the present invention.

Fig. 15 is a particle size test chart of the ternary precursor with a narrow particle size distribution prepared in embodiment 3 of the present invention.

Fig. 16 is a particle size test chart of the ternary precursor prepared in comparative example 2 of the present invention.

Fig. 17 is a particle size test chart of the ternary precursor with a narrow particle size distribution prepared in embodiment 4 of the present invention.

Fig. 18 is a particle size test chart of the ternary precursor prepared in comparative example 3 of the present invention.

Fig. 19 is a particle size test chart of the ternary precursor with a narrow particle size distribution prepared in embodiment 5 of the present invention.

Fig. 20 is a particle size test chart of the ternary precursor prepared in comparative example 4 of the present invention.

Fig. 21 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 10 of the present invention.

Fig. 22 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 11 of the present invention.

Fig. 23 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 12 of the present invention.

Fig. 24 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 13 of the present invention.

Fig. 25 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 14 of the present invention.

Fig. 26 is an SEM electron micrograph of a ternary precursor with a narrow particle size distribution prepared according to embodiment 15 of the present invention.

In the figure: reaction apparatus-100; a reaction device body-200; a feed inlet-210; discharge opening-220; stirring device-300; concentrating device-400; a fixing piece-410, a filtering piece-420; a filter element-421; a filtered liquid collecting device-422; a filtrate discharge member-430; -440, a connection means; pressure extraction device-500; valve-510.

Detailed Description

The present invention will be described in detail with reference to the following embodiments. The following embodiments will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

As shown in fig. 2, the reaction apparatus 100 for a ternary precursor with a narrow particle size distribution: the device comprises a reaction device body 200 and a stirring device 300, wherein the reaction device body is provided with a feeding hole 210 and a discharging hole 220; the concentration device 400 is used for increasing the concentration of the ternary precursor solution in the reaction device, and the concentration device promotes the ternary precursor solution in the reaction device to react to generate the ternary precursor with narrow particle size distribution.

In some embodiments of the present invention, the first and second electrodes are,the reaction device is used for producing the ternary precursor with narrow particle size distribution, and the chemical composition of the ternary precursor with narrow particle size distribution is Ni_xCo_yM_1-x-y(OH)₂Wherein x is more than or equal to 0.40 and less than or equal to 0.98, y is more than or equal to 0.02 and less than or equal to 0.3, and x + y is less than 1. Specifically, in some embodiments of the present invention, M is a mixture of one or more of Mn, a1, Zr, and Ti. In the present invention, when M is one of Mn, a1, Zr, and Ti, it is a ternary precursor. When M is a mixture of multiple Mn, A1, Zr and Ti, M is a multi-element precursor and is referred to as a ternary precursor in the invention.

As shown in fig. 2, the bottom of the concentration device 400 of the present invention is located slightly below the full level line of the reaction device. Therefore, when the liquid level of the solution in the reaction device reaches the position of the full liquid level line, the concentration device is immediately started, precursor crystal nuclei in the reaction device are remained in the reaction device for continuous reaction through filtration, the filtered solution is discharged out of the reaction device, and solution components in the reaction device can be kept in a relatively balanced environment, so that the ternary precursor with narrow particle size distribution is obtained.

As shown in fig. 2, the reaction apparatus 100 for a ternary precursor with a narrow particle size distribution: the device comprises a reaction device body 200 and a stirring device 300, wherein the reaction device body is provided with a feeding hole 210 and a discharging hole 220; the concentration device 400 is used for increasing the concentration of the ternary precursor solution in the reaction device, and the concentration device promotes the ternary precursor solution in the reaction device to react to generate the ternary precursor with narrow particle size distribution. The concentration device comprises: a fixing member 410 having both ends connected to the filter member 420 and the reaction device body, respectively, for fixing the filter member; a filter element 420, one end of which is connected to the fixing element and the other end of which is connected to the clear liquid drain element 430, for filtering the clear liquid in the ternary precursor solution when the ternary precursor solution in the reaction device body reaches the full liquid level line and increasing the concentration of the ternary precursor solution in the reaction device body; and a filtered liquid discharging member 430, one end of which is connected to the filter member 420, and the other end thereof, which is far from the end connected to the filter member, is connected to the reaction device body 200, and extends to the outside of the reaction device body; wherein, the fixing piece, the filter piece, the filtered liquid discharging piece and the reaction device body form a closed area.

In one embodiment of the invention, the filter element comprises at least one series of filter elements 421. In particular, in some embodiments of the invention, the filter element comprises one to ten unequal sets of filter elements. More specifically, the filter element includes one to five unequal sets of filter elements. In one embodiment of the invention, the filter element comprises a series of filter elements. In another embodiment of the invention, the filter pack includes five sets of filter elements. In yet another embodiment of the invention, the filter pack includes ten sets of filter elements. In the application, the number of the filter elements can be flexibly selected according to the reaction device and the expected requirement, and no limitation is made on the number of the filter elements. Meanwhile, it should be noted that when the number of filter elements is too large, unnecessary reduction of the filtering efficiency and increase of the filtering cost will be caused.

As shown in fig. 2, the reaction apparatus 100 for a ternary precursor with a narrow particle size distribution: the device comprises a reaction device body 200 and a stirring device 300, wherein the reaction device body is provided with a feeding hole 210 and a discharging hole 220; the concentration device 400 is used for increasing the concentration of the ternary precursor solution in the reaction device, and the concentration device promotes the ternary precursor solution in the reaction device to react to generate the ternary precursor with narrow particle size distribution. The concentration device comprises: a fixing member 410 having both ends connected to the filter member 420 and the reaction device body, respectively, for fixing the filter member; one end of the filter element is connected with the fixing element, and the other end, far away from the end connected with the fixing element, of the filter element is connected with a filtered solution discharge element 430, so that when the ternary precursor solution in the reaction device body reaches a full liquid level line, the filter element is used for filtering the filtered solution in the ternary precursor solution, and the concentration of the ternary precursor solution in the reaction device body is improved; one end of the filtered liquid discharging member is connected to the filtering member 420, and the other end thereof, which is far away from the end connected to the filtering member, is connected to the reaction device body 100 and extends to the outside of the reaction device body; wherein, the fixing piece, the filter piece, the filtered liquid discharging piece and the reaction device body form a closed area. The part of the filtered liquid discharging member 430 extending to the outside of the reaction device body is further connected with a pressure extraction device 500 for changing the filtering efficiency of the filter member. Generally, the filter element can realize that the filter liquor discharged after being filtered by the filter element is in dynamic balance with the volume of the ternary precursor solution simultaneously added into the reaction device. In another case, when the instantaneous volume of the solution of the ternary precursor added into the reaction device is larger than the filtered clear solution discharged after filtering by the filter element, the volume of the solution in the reaction device will be continuously increased, which may cause overflow on one hand and change of the reaction environment in the reaction device on the other hand, thereby affecting the particle size distribution of the ternary precursor. Therefore, at this time, an external pressure extraction device 500 is required, positive pressure is formed inside and outside the filter element, so that the filtration efficiency is improved, and the volume of the filtered solution discharged after the filtration by the filter element in the reaction device and the volume of the ternary precursor solution simultaneously added into the reaction device body are in instantaneous dynamic balance. It can be understood that, in the present invention, when the instantaneous volume of the ternary precursor solution added into the reaction device is smaller than the filtered clear solution discharged after being filtered by the filter element, on one hand, the filter element with smaller filter holes can be replaced, and on the other hand, the reverse pressure can be formed by the pressure extraction device, so as to reduce the filtering efficiency of the filter element, and realize the instantaneous dynamic balance between the discharged clear solution and the volume of the ternary precursor solution added into the reaction device body.

Further, in an embodiment of the present invention, at least one valve 510 is further disposed on the pressure extraction device for adjusting the pressure generated by the pressure extraction device, so that when the filter element of the concentration device is used for filtering, the filtered liquid discharged after filtering through the filter element in the reaction device and the volume of the ternary precursor solution simultaneously added into the reaction device are in instantaneous dynamic equilibrium more rapidly and accurately.

As shown in fig. 3, in one embodiment of the present invention, a filtered liquid collecting device 422 is connected to at least one end of the filter element 421, and the filtered liquid collecting device is connected to the filtered liquid discharging member 430 through a connecting device 440, so that the filtered liquid can be smoothly discharged from the filtered liquid discharging member. It will be appreciated that in other embodiments of the invention, a filtrate collection device may be connected to each end of the filter element. From the practical effect, any end of the filter element is connected with a filtered liquid collecting device, filtered liquid in the filter element is collected, and the filtered liquid is connected with the filtered liquid discharging piece, so that the filtered liquid filtered by the filter element can be smoothly discharged.

In one embodiment of the present invention, as shown in fig. 2, the filtrate discharging member and the filtrate collecting means each have a hollow pipe. Specifically, the filtered liquid discharging member and the filtered liquid collecting device may have the same diameter of the hollow pipe. It can be understood that, in the present invention, the diameters of the hollow pipes of the filtered liquid discharging member and the filtered liquid collecting device may be different, and at this time, the corresponding connecting device 440 only needs to be adopted at the connecting position of the hollow pipes of the filtered liquid discharging member and the filtered liquid collecting device. In the present invention, the filtered liquid discharging member and the filtered liquid collecting device have the same diameter of the hollow pipe, and the connecting device may be a flange, but it should be understood that other connecting devices such as a screw connection, etc. capable of achieving a substantially sealed structure are all possible. Specifically, in the present invention, when the filtered liquid discharging member is connected to the hollow pipe of the filtered liquid collecting device by a flange, a sealing gasket is further provided to enhance the sealing effect between the hollow pipes of the filtered liquid discharging member 430 and the filtered liquid collecting device 422. The sealing gasket is made of an elastic material, and specifically can be a rubber gasket, a metal gasket (such as copper), a plastic gasket (such as polytetrafluoroethylene) or a graphite plate gasket. In the invention, the sealing washer is a silica gel washer.

In some embodiments of the present invention, a method for preparing a narrow particle size distribution ternary precursor comprises the steps of:

a nucleation stage: adding the mixed solution A, the solution B and the solution C into a reaction device at the same time according to a preset proportion, and fully reacting to form a crystal nucleus;

and (3) growth stage: after nucleation is finished, continuously adding the mixed solution A, the first strong alkaline solution B1 and the first complexing agent solution C1 into the reaction device at the same time according to a preset proportion, so that the crystal nucleus continues to grow, and during the period, when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device, concentrating, so that the filtrate is discharged out of the reaction device, and the crystal nucleus continues to grow in the reaction device until the crystal nucleus grows to a target particle size;

In some embodiments of the present invention, the molar ratio of the nickel ions, the cobalt ions, and the M ions in the mixed solution a may be adjusted according to actual needs, which is not specifically limited in this application. For example, the following conditions are satisfied:

specifically, in some embodiments of the present invention, the step of simultaneously adding the mixed solution a, the first strongly basic solution B1 and the first complexing agent solution C1 in a predetermined ratio into a reaction device in the step nucleation stage means that the mixed solution a, the first strongly basic solution B1 and the first complexing agent solution C1 are continuously added into the reaction device at a predetermined speed simultaneously. In an embodiment of the present invention, the first complexing agent is ammonia water, and the ammonia concentration of the ammonia water is 1.0 to 12.0 mol/L. The time for continuously adding the ammonia water can be controlled between 1 and 5 hours. In other embodiments of the present invention, the first complexing agent may also be at least one of ammonium sulfate, ethylenediaminetetraacetic acid (EDTA), sodium bicarbonate, and oxalic acid. In the step growth stage, after nucleation is finished, continuously adding the mixed solution a, the first strongly alkaline solution B1 and the first complexing agent solution C1 into a reaction device at the same time according to a preset ratio, namely, continuously adding the mixed solution a, the first strongly alkaline solution B1 and the first complexing agent solution C1 into the reaction device at the same time at a preset speed so as to grow crystal nuclei. And (3) with the continuous addition of the mixed solution A, the first strong alkaline solution B1 and the first complexing agent solution C1, the volume of the total solution in the reaction device is continuously increased, when the volume of the solution in the reaction device reaches a full liquid level, the concentration device in the reaction device is started, the filtrate is discharged out of the reaction device, and the crystal nucleus continues to be remained in the reaction device for growth until the crystal nucleus grows to the target particle size. And then stopping feeding, and carrying out solid-liquid separation, pure water washing and drying on the precursor solution in the reaction device to obtain the ternary precursor with narrow particle size distribution.

Embodiment 1:

preparing a solution: preparing a mixed solution A of nickel ions, cobalt ions and Mn ions, a first strongly alkaline solution B1 and a first complexing agent solution C1 according to a predetermined molar ratio (such as 8:1: 1); wherein the total metal concentration in the mixed solution A is 2.0mol/L, the first strong alkaline solution B1 is a sodium hydroxide solution, the hydroxide concentration in B1 is 7.0mol/L, the first complexing agent solution C1 is an ammonia water solution, and the ammonia concentration in C1 is 8.0 mol/L;

preparing a base solution: adding a proper amount of pure water and ammonia water into a reaction device to ensure that the ammonia concentration in a base solution is 0.5mol/L, continuously adding a sodium hydroxide solution, adjusting the pH value of the base solution to 12.5, ensuring that the volume of the base solution in the reaction device accounts for 0.5 of the full liquid level volume of the reaction device, and heating the temperature of the base solution to 50 ℃;

a nucleation stage: and simultaneously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 450rpm, the temperature at 50 ℃, the pH value at 12.5 and the nucleation time at 4.0 hours. Fully reacting to form crystal nucleus;

and (3) growth stage: after nucleation is finished, continuously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 300rpm, the temperature at 50 ℃ and the pH value at 11.8, continuously growing for 90 hours, and carrying out concentration treatment when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device during the period, so that the filtered liquid is discharged out of the reaction device through a filter element, and crystal nuclei are remained in the reaction device to continuously grow until the ternary precursor crystal nuclei D50 grow to 3.0 +/-0.5 mu m;

and (3) post-treatment stage: and when the crystal nucleus in the reaction device grows to the target granularity, stopping feeding, and performing solid-liquid separation, pure water washing and 110 ℃ blast drying by using a centrifugal machine to obtain the ternary precursor with narrow particle size distribution.

Embodiment 2:

preparing a solution: preparing a mixed solution A of nickel ions, cobalt ions and Mn ions, a first strongly alkaline solution B1 and a first complexing agent solution C1 according to a preset molar ratio (such as 6:2: 2); wherein the total metal concentration in the mixed solution A is 1.8mol/L, the first strong alkaline solution B1 is a sodium hydroxide solution, the hydroxide concentration in B1 is 10.0mol/L, the first complexing agent solution C1 is an ammonia water solution, and the ammonia concentration in C1 is 6.0 mol/L;

preparing a base solution: adding a proper amount of pure water and ammonia water into a reaction device to ensure that the ammonia concentration in a base solution is 0.3mol/L, continuously adding a sodium hydroxide solution, adjusting the pH value of the base solution to 12.2, ensuring that the volume of the base solution in the reaction device accounts for 0.4 of the full liquid level volume of the reaction device, and heating the temperature of the base solution to 52 ℃;

a nucleation stage: and simultaneously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 490rpm, the temperature at 52 ℃, the pH value at 12.2 and the nucleation time at 5.0 hours. Fully reacting to form crystal nucleus;

and (3) growth stage: after nucleation is finished, continuously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 400rpm, controlling the temperature at 52 ℃ and the pH value at 11.95, continuously growing for 45 hours, and carrying out concentration treatment when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device during the period, so that the filtered liquid is discharged out of the reaction device through a filter element, and crystal nuclei are remained in the reaction device to continuously grow until the ternary precursor crystal nuclei D50 grow to 6.0 +/-0.5 mu m;

Embodiment 3:

preparing a solution: preparing a mixed solution A of nickel ions, cobalt ions and Mn ions, a first strong alkaline solution B1 and a first complexing agent solution C1 according to a preset molar ratio; wherein the total metal concentration in the mixed solution A is 1.5mol/L, the first strong alkaline solution B1 is a sodium hydroxide solution, the hydroxide concentration in B1 is 12.0mol/L, the first complexing agent solution C1 is an ammonia water solution, and the ammonia concentration in C1 is 4.0 mol/L;

preparing a base solution: adding a proper amount of pure water and ammonia water into a reaction device to ensure that the ammonia concentration in a base solution is 0.2mol/L, continuously adding a sodium hydroxide solution, adjusting the pH value of the base solution to 12.0, ensuring that the volume of the base solution in the reaction device accounts for 0.3 of the full liquid level volume of the reaction device, and heating the temperature of the base solution to 65 ℃;

a nucleation stage: and simultaneously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 500rpm, the temperature at 65 ℃, the pH value at 12.0 and the nucleation time at 5.0 hours. Fully reacting to form crystal nucleus;

and (3) growth stage: after nucleation is finished, continuously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 300rpm, controlling the temperature at 65 ℃ and the pH value at 12.0, continuously growing for 10 hours, and carrying out concentration treatment when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device during the period, so that the filtered liquid is discharged out of the reaction device through a filter element, and crystal nuclei are remained in the reaction device to continuously grow until the ternary precursor crystal nuclei D50 grow to 11.0 +/-0.5 mu m;

Embodiment 4:

preparing a solution: preparing a mixed solution A of nickel ions, cobalt ions and Al ions, a first strong alkaline solution B1 and a first complexing agent solution C1 according to a preset molar ratio; wherein the total metal concentration in the mixed solution A is 1.0mol/L, the first strong alkaline solution B1 is a sodium hydroxide solution, the hydroxide concentration in B1 is 8.0mol/L, the first complexing agent solution C1 is an ammonia water solution, and the ammonia concentration in C1 is 1.0 mol/L;

preparing a base solution: adding a proper amount of pure water and ammonia water into a reaction device to ensure that the ammonia concentration in a base solution is 0.7mol/L, continuously adding a sodium hydroxide solution, adjusting the pH value of the base solution to 11.8, ensuring that the volume of the base solution in the reaction device accounts for 0.2 of the full liquid level volume of the reaction device, and heating the temperature of the base solution to 70 ℃;

a nucleation stage: and simultaneously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 400rpm, the temperature at 70 ℃, the pH value at 12.8 and the nucleation time at 3.0 hours. Fully reacting to form crystal nucleus;

and (3) growth stage: after nucleation is finished, continuously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 350rpm, controlling the temperature at 70 ℃ and the pH value at 11.5, continuously growing for 70 hours, and carrying out concentration treatment when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device during the period, so that the filtered liquid is discharged out of the reaction device through a filter element, and crystal nuclei are remained in the reaction device to continuously grow until the ternary precursor crystal nuclei D50 grow to 14.0 +/-0.5 mu m;

Embodiment 5:

preparing a solution: preparing a mixed solution A of nickel ions, cobalt ions and Al ions, a first strong alkaline solution B1 and a first complexing agent solution C1 according to a preset molar ratio; wherein the total metal concentration in the mixed solution A is 0.5mol/L, the first strong alkaline solution B1 is a sodium hydroxide solution, the hydroxide concentration in B1 is 1.0mol/L, the first complexing agent solution C1 is an ammonia water solution, and the ammonia concentration in C1 is 10.0 mol/L;

preparing a base solution: adding a proper amount of pure water and ammonia water into a reaction device to ensure that the ammonia concentration in a base solution is 0.9mol/L, continuously adding a sodium hydroxide solution, adjusting the pH value of the base solution to 11.5, ensuring that the volume of the base solution in the reaction device accounts for 0.5 of the full liquid level volume of the reaction device, and heating the temperature of the base solution to 80 ℃;

a nucleation stage: and simultaneously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 300rpm, the temperature at 80 ℃, the pH value at 12.6 and the nucleation time at 2.0 hours. Fully reacting to form crystal nucleus;

and (3) growth stage: after nucleation is finished, continuously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 200rpm, the temperature at 80 ℃ and the pH value at 11.2, continuously growing for 25 hours, and carrying out concentration treatment when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device during the period, so that the filtered liquid is discharged out of the reaction device through a filter element, and crystal nuclei are remained in the reaction device to continuously grow until the ternary precursor crystal nuclei D50 grow to 17.6 +/-0.5 mu m;

Embodiment 6:

preparing a solution: preparing a mixed solution A of nickel ions, cobalt ions and Al ions, a first strong alkaline solution B1 and a first complexing agent solution C1 according to a preset molar ratio; wherein the total metal concentration in the mixed solution A is 2.5mol/L, the first strong alkaline solution B1 is a sodium hydroxide solution, the hydroxide concentration in B1 is 4.0mol/L, the first complexing agent solution C1 is an ammonia water solution, and the ammonia concentration in C1 is 12.0 mol/L;

preparing a base solution: adding a proper amount of pure water and ammonia water into a reaction device to enable the ammonia concentration in a base solution to be 1.0mol/L, continuously adding a sodium hydroxide solution, adjusting the pH value of the base solution to be 13.0, enabling the volume of the base solution in the reaction device to be 0.5 of the full liquid level volume of the reaction device, and heating the temperature of the base solution to 40 ℃;

a nucleation stage: and simultaneously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 200rpm, the temperature at 40 ℃, the pH value at 13.0 and the nucleation time at 1.0 hour.

Fully reacting to form crystal nucleus;

and (3) growth stage: after nucleation is finished, continuously adding the mixed solution A, the sodium hydroxide solution and the ammonia water solution into a reaction device according to a preset proportion, controlling the stirring speed at 300rpm, the temperature at 40 ℃ and the pH value at 10.5, continuously growing for 100 hours, and carrying out concentration treatment when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device during the period, so that the filtered liquid is discharged out of the reaction device through a filter element, and crystal nuclei are remained in the reaction device to continuously grow until the ternary precursor crystal nuclei D50 grow to 16.0 +/-0.5 mu m;

Embodiment 7:

the first strongly basic solution B1 and the second strongly basic solution B2 are both potassium hydroxide, and the rest is the same as embodiment 1.

Embodiment 8:

the metal ions M are Al and Mn, and the rest is the same as embodiment 1.

Embodiment 9:

the metal ion M is Ti or Zr, and the rest is the same as embodiment 1.

Embodiments 10 to 12:

repeat embodiment 1, 3 times.

Embodiments 13 to 15:

repeat embodiment 5, 3 times.

Comparative example 1:

in the step growth stage, after the solution in the reaction device reaches the full liquid level, a concentration device outside the reaction device is started, the filtered solution is separated from the precursor crystal nucleus slurry in a settling or centrifugal filtration mode, the filtered solution is discharged through the concentration device outside the reaction device, the slurry in the concentration device is pumped into the reaction device by a pneumatic pump, and the crystal nucleus returns to the reaction system in the reaction device to continue to grow. The other conditions were the same as in embodiment 1.

Comparative example 2:

in the step growth stage, after the solution in the reaction device reaches the full liquid level, a concentration device outside the reaction device is started, the filtered solution is separated from the precursor crystal nucleus slurry in a settling or centrifugal filtration mode, the filtered solution is discharged through the concentration device outside the reaction device, the slurry in the concentration device is pumped into the reaction device by a pneumatic pump, and the crystal nucleus returns to the reaction system in the reaction device to continue to grow. The other conditions were the same as in embodiment 3.

Comparative example 3:

in the step growth stage, after the solution in the reaction device reaches the full liquid level, a concentration device outside the reaction device is started, the filtered solution is separated from the precursor crystal nucleus slurry in a settling or centrifugal filtration mode, the filtered solution is discharged through the concentration device outside the reaction device, the slurry in the concentration device is pumped into the reaction device by a pneumatic pump, and the crystal nucleus returns to the reaction system in the reaction device to continue to grow. The other conditions were the same as in embodiment 4.

Comparative example 4:

in the step growth stage, after the solution in the reaction device reaches the full liquid level, a concentration device outside the reaction device is started, the filtered solution is separated from the precursor crystal nucleus slurry in a settling or centrifugal filtration mode, the filtered solution is discharged through the concentration device outside the reaction device, the slurry in the concentration device is pumped into the reaction device by a pneumatic pump, and the crystal nucleus returns to the reaction system in the reaction device to continue to grow. The other conditions were the same as in embodiment 5.

The ternary precursors with narrow particle size distribution obtained in embodiments 1 to 5 and comparative examples 1 to 4 were subjected to SEM and laser particle size tests. Table 1 shows the results of the laser particle size tests of embodiments 1 to 5 and comparative examples 1 to 4.

TABLE 1 particle size of precursors of embodiments 1 to 5 and comparative examples 1 to 4

Experiment number	D10(μm)	D50(μm)	D90(μm)	(D90-D10)/D50
					Embodiment mode 1	2.346	3.458	5.048	0.781
Comparative example 1	2.283	3.538	5.514	0.913
					Embodiment mode 2	4.14	5.823	7.977	0.659
Embodiment 3	9.492	11.181	13.043	0.318
					Comparative example 3	9.014	11.017	13.484	0.405
Embodiment 4	11.716	14.059	16.599	0.347
					Comparative example 4	11.504	13.981	16.859	0.383
Embodiment 5	16.099	17.621	19.813	0.211
					Comparative example 5	14.880	17.660	20.837	0.337

TABLE 2 particle size of precursor in embodiments 10 to 15

Experiment number	D10(μm)	D50(μm)	D90(μm)	(D90-D10)/D50
					Embodiment
10	2.325	3.336	4.715	0.716
					Comparative example 11	2.338	3.331	4.680	0.703
Embodiment 12	2.335	3.327	4.672	0.702
					Embodiment 13	15.050	17.678	20.690	0.319
Embodiment 14	15.094	17.646	20.582	0.311
					Embodiment 15	15.101	17.716	20.696	0.316

Wherein, the laser particle size tester is Marenvin 2000, the testing medium is water, and the refractive index of the particles is 2.6.

FIGS. 4 to 12 are SEM electron micrographs of the ternary precursors having narrow particle size distributions obtained in embodiments 1 to 5 and comparative examples 1 to 4.

As can be seen from table 1 and fig. 4 to 12, the precursors prepared in embodiments 1 to 5 have good consistency and no pellets. In comparative examples 1-4, the method of concentrating outside the kettle and returning to the reaction device is adopted, the particle size distribution is wide, and a plurality of small-particle-size particles exist, which seriously affects the performance quality of the precursor.

Fig. 13 to 20 are particle size test distribution diagrams of the ternary precursors obtained in embodiments 1 to 4 and comparative examples 1 to 4, and it can be seen that the ternary precursors with narrow particle size distributions of different particle sizes prepared in the embodiment of the present invention have high particle size distribution concentration, narrow particle size distribution range, and excellent quality.

As can be seen from tables 1 and 2, the repeated results of embodiment 1 and embodiment 5 are good in stability, and the narrow-particle-size precursors obtained from a plurality of batches are good in consistency, so that the method has great market potential.

FIGS. 21 to 26 are SEM electron micrographs of the ternary precursors having a narrow particle size distribution obtained in embodiments 10 to 15. As can be seen from the electron microscope picture in the figure, the ternary precursor with different particle sizes and narrow particle size distribution, which is prepared in the embodiment of the invention, has high stability among batches and good uniformity, and is suitable for large-scale production and application.

Results and conclusions: the ternary precursor with narrow particle size distribution prepared by the embodiment of the invention has narrower particle size distribution and higher control precision, and a filter in a filtering device can be replaced according to production requirements to adjust the pore size, so that precursor particles with expected particle size and narrower particle size distribution are obtained. The problem that in the prior art, after overflow liquid is settled by adopting a middle tank, a concentration tank and the like, the overflow liquid is conveyed to a reaction kettle by a pump to grow continuously is avoided, and on one hand, partial ternary crystal nucleus particles are extruded mutually when conveyed in a pump pipe, so that the surface appearance of a precursor is damaged or a precursor sphere is crushed; on the other hand, after the ternary crystal nucleus particles entering the intermediate tank or the concentration tank leave the initial reaction system, the ternary crystal nucleus particles enter the reaction kettle again for reaction, so that the growth is not uniform, the obtained ternary precursor has nonuniform particle size, and the ternary precursor with good particle size growth uniformity is obtained.

In the description of the present invention, it is to be understood that the terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit indication of the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, unless otherwise explicitly specified or limited, the terms "connected" and the like are to be construed broadly, e.g., as fixed or removable connections or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the various embodiments or examples and features of the various embodiments or examples described in this specification can be combined and combined by those skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and those skilled in the art can make changes, modifications, substitutions and alterations to the above embodiments within the scope of the present invention.

Claims

1. The preparation method of the ternary precursor with narrow particle size distribution is characterized by comprising the following steps:

a nucleation stage: adding the mixed solution A, the first strong alkaline solution B1 and the first complexing agent solution C1 into the base solution at the same time, and fully reacting to form crystal nuclei;

and (3) growth stage: after nucleation is finished, continuing to grow the crystal nucleus by continuing to use the mixed solution A, the first strong alkaline solution B1 and the first complexing agent solution C1, and during the period, when the solution in the reaction device reaches or is lower than the full liquid level of the reaction device, carrying out concentration treatment, discharging the filtrate out of the reaction device, and continuing to remain in the reaction device for growing the crystal nucleus until the crystal nucleus grows to the target particle size;

and (3) post-treatment stage: stopping feeding after crystal nuclei in the reaction device grow to a target particle size, and performing solid-liquid separation, washing and drying to obtain a ternary precursor with narrow particle size distribution;

wherein, the M ion is one or a mixture of Mn, A1, Zr and Ti.

2. The method for preparing a ternary precursor having a narrow particle size distribution according to claim 1, wherein: the reaction device is a circulating flux reaction kettle.

3. The method for preparing a ternary precursor having a narrow particle size distribution according to claim 1, wherein: the total metal concentration in the mixed solution A is 0.5-2.5 mol/L.

4. The method for preparing a ternary precursor having a narrow particle size distribution according to claim 1, wherein: the pH value of the base solution is 11.5-13.0, and the volume of the base solution is 0.2-0.5 times of the full liquid level volume of the reaction device.

5. The method for preparing a ternary precursor having a narrow particle size distribution according to claim 4, wherein: the molar concentration of the second complexing agent C2 in the base solution is 0.2-1.0 mol/L.

6. The method for preparing a ternary precursor having a narrow particle size distribution according to claim 1, wherein: the reaction temperature of the nucleation stage is 40-80 ℃, the reaction time is 1-5 h, and the reaction pH is 12.0-13.0.

7. The method for preparing a ternary precursor having a narrow particle size distribution according to claim 1, wherein: the reaction temperature in the growth stage is 40-80 ℃, the reaction time is 10-100 h, and the reaction pH is 10.5-12.0.

8. The method for preparing a ternary precursor having a narrow particle size distribution according to any one of claims 1 to 7, wherein: the first strong alkaline solution B1 is at least one of sodium hydroxide and potassium hydroxide, and the first complexing agent solution C1 is at least one of ammonia water, ammonium sulfate, ethylene diamine tetraacetic acid, sodium bicarbonate and oxalic acid.

9. The method for preparing a ternary precursor having a narrow particle size distribution according to claim 8, wherein: the second strong alkaline solution B2 is at least one of sodium hydroxide and potassium hydroxide, and the second complexing agent solution C2 is at least one of ammonia water, ammonium sulfate, ethylene diamine tetraacetic acid, sodium bicarbonate and oxalic acid.

10. The method for preparing a ternary precursor having a narrow particle size distribution according to claim 9, wherein: the concentration of hydroxide in the first strong alkaline solution B1 and the second strong alkaline solution B2 is 1.0-12.0 mol/L.