Dynamic adjustment method for particle size distribution of ternary precursor large particles

Abstract

The invention relates to a method for dynamically adjusting the particle size distribution of ternary precursor large particles, which comprises the following steps: (1) mixing a ternary mixed salt solution, a precipitator solution and a complexing agent solution in a base solution in a parallel flow manner, and carrying out first coprecipitation reaction to obtain a seed crystal solution with the particle size D50 of 3-5 microns and the solid content of 100g / L-200g / L; (2) the ternary mixed salt solution, the precipitant solution and the complexing agent solution are mixed in the base solution in a parallel flow mode, and a second coprecipitation reaction is conducted; and when the second coprecipitation reaction is performed until the particle size D50 is 7-10 [mu] m, the seed crystal solution in the step (1) is additionally introduced in parallel, and the third coprecipitation reaction is performed until the target particle size is reached, so that the ternary precursor is obtained. According to the dynamic adjustment method provided by the invention, the particle size distribution interval of the large-particle-size ternary precursor can be stably and efficiently reduced, and the strict requirement of a high-performance lithium ion battery on the ternary positive electrode material is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and relates to a preparation method of a ternary precursor, in particular to a method for dynamically adjusting the particle size distribution of large particles of a ternary precursor. BACKGROUND

[0002] Under the background of rapid development of the new energy industry, lithium ion batteries have become the core power source in the fields of electric vehicles and energy storage systems due to their high energy density and long cycle life. Among them, ternary cathode materials occupy an important market share because they can effectively balance the energy density and cycle performance of batteries. The micro-morphology and physicochemical properties of ternary precursors, which are key precursors of ternary cathode materials, directly determine the electrochemical performance of the final cathode materials.

[0003] Large particle size ternary precursors (usually with a particle size D50 of 15 μm or more) can significantly improve the volume energy density of cathode materials due to their high tap density, thus meeting the demand for high energy density of high-end power batteries. Therefore, large particle size ternary precursors have become a hot spot in current industry research and application. However, during the preparation process of large particle size ternary precursors, a wide particle size distribution problem often occurs, specifically, the particle size distribution interval is too large. This wide distribution defect can cause a series of adverse consequences: on the one hand, during the subsequent mixing and sintering process with lithium source, the reaction activity of precursor particles of different particle sizes differs greatly, which easily leads to uneven sintering, resulting in the generation of impurities or lattice defects in the cathode material, and reducing the cycle stability of the battery; on the other hand, the wide particle size distribution increases the fluctuation of the packing density of precursor particles, affecting the uniformity of cathode slurry coating, and thus leading to a decrease in battery consistency and increasing the safety hazards of battery packs.

[0004] To solve the problem of wide particle size distribution of large particle size ternary precursors, existing technologies mainly optimize the preparation process, such as adjusting the stirring speed in the reaction kettle, controlling the stability of reaction temperature and pH value, and optimizing the feeding mode. However, these methods have obvious limitations in practical application: adjusting the stirring speed can affect the particle growth environment to some extent, but for large particle size particles, it is difficult to achieve uniformity of mass transfer in the whole reaction system by relying solely on mechanical stirring, which easily leads to significant differences in particle growth rate in local areas; controlling the stability of reaction temperature and pH value requires a high-precision control system, which not only increases the cost of production equipment, but also in large-scale industrial production, due to factors such as heat dissipation of the reaction system and batch differences, it is difficult to maintain the absolute stability of parameters for a long time, and the improvement effect of particle size distribution is limited; optimizing the feeding mode can regulate the nucleation and growth stages of particles, but for the growth process of large particle size particles, the kinetics is complex, and it is difficult to precisely control the growth rate of particles by simply adjusting the feeding mode, resulting in unsatisfactory narrowing effect of particle size distribution.

[0005] In addition, part of the prior art attempts to improve the particle size distribution by post-processing process (such as screening), but the screening process will cause a large amount of material waste, reduce production efficiency, and cannot fundamentally solve the problem of wide particle size distribution in the preparation process of the precursor, which does not meet the economic requirements of industrial production.

[0006] Therefore, for the problem of wide particle size distribution of large particle size ternary precursor, the prior art is difficult to achieve effective balance between precise regulation of the preparation process and economy of industrial application, and a new technical scheme is urgently needed to efficiently and stably reduce the particle size distribution range of large particle size ternary precursor, so as to meet the stringent requirements of high-performance lithium ion batteries on ternary cathode materials. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a dynamic adjustment method for the particle size distribution of large particles of ternary precursor, which can stably and efficiently reduce the particle size distribution range of large particle size ternary precursor, and meet the stringent requirements of high-performance lithium ion batteries on ternary cathode materials.

[0008] To achieve the purpose of the present application, the following technical solutions are adopted:

[0009] The present application provides a dynamic adjustment method for the particle size distribution of large particles of ternary precursor, the dynamic adjustment method comprising:

[0010] (1) mixing ternary mixed salt solution, precipitant solution and complexing agent solution in parallel in the bottom liquid to carry out the first co-precipitation reaction, and obtain a crystal seed solution with a particle size D50 of 3-5 μm and a solid content of 100-200 g / L;

[0011] (2) mixing ternary mixed salt solution, precipitant solution and complexing agent solution in parallel in the bottom liquid to carry out the second co-precipitation reaction; when the second co-precipitation reaction reaches a particle size D50 of 7-10 μm, the crystal seed solution of step (1) is additionally introduced in parallel, and the third co-precipitation reaction reaches the target particle size to obtain the ternary precursor.

[0012] This invention utilizes seed crystals with a specific particle size (D50) to provide a unified initial template for precursor particle growth. This transforms disordered homogeneous nucleation in the reaction system into ordered heterogeneous nucleation, allowing metal ions to preferentially deposit on the seed crystal surface. This avoids the disordered formation of new nuclei caused by fluctuations in local supersaturation, thereby eliminating initial particle size differences caused by varying nucleation time differences. The seed crystal solution with a specific solid content precisely controls the number density of seed crystals in the reaction system. This ensures that the total amount of seed crystals is sufficient to consume the system's supersaturation to suppress new nuclei formation, while also guaranteeing that each seed crystal has a uniform growth space. This ensures that the deposition rate of metal ions on each seed crystal surface is consistent, avoiding growth rate imbalances caused by too many or too few seed crystals. Consequently, precursor particles grow synchronously from nearly identical initial states, reducing small particle residue and abnormal growth of large particles, ultimately achieving an effective reduction in the particle size distribution range of large-diameter ternary precursors.

[0013] Preferably, the precipitant solution comprises a sodium hydroxide solution with a mass concentration of 20wt% to 40wt%, for example, it may be 20wt%, 25wt%, 30wt%, 35wt% or 40wt%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0014] Preferably, the complexing agent solution comprises ammonia water with a mass concentration of 10wt% to 20wt%, for example, it can be 10wt%, 12wt%, 15wt%, 16wt%, 18wt% or 20wt%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0015] Preferably, the ternary mixed salt in the ternary mixed salt solution includes nickel salt, cobalt salt and manganese salt.

[0016] Preferably, the total concentration of nickel salt, cobalt salt and manganese salt in the ternary mixed salt solution is 2 mol / L to 2.5 mol / L, for example, it can be 2 mol / L, 2.1 mol / L, 2.2 mol / L, 2.4 mol / L or 2.5 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the nickel salt includes any one or a combination of at least two of nickel sulfate, nickel chloride, or nickel nitrate. Typical but non-limiting combinations include combinations of nickel sulfate and nickel chloride, nickel chloride and nickel nitrate, nickel sulfate and nickel nitrate, or combinations of nickel sulfate, nickel chloride, and nickel nitrate.

[0018] Preferably, the cobalt salt includes any one or a combination of at least two of cobalt sulfate, cobalt chloride, or cobalt nitrate. Typical but non-limiting combinations include a combination of cobalt sulfate and cobalt chloride, a combination of cobalt chloride and cobalt nitrate, a combination of cobalt sulfate and cobalt nitrate, or a combination of cobalt sulfate, cobalt chloride, and cobalt nitrate.

[0019] Preferably, the manganese salt includes any one or a combination of at least two of manganese sulfate, manganese chloride, or manganese nitrate. Typical but non-limiting combinations include combinations of manganese sulfate and manganese chloride, manganese chloride and manganese nitrate, manganese sulfate and manganese nitrate, or combinations of manganese sulfate, manganese chloride, and manganese nitrate.

[0020] Preferably, during the first coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8 L / h to 10 L / h, the flow rate of the precipitant solution is 3 L / h to 5 L / h, and the flow rate of the complexing agent solution is 1 L / h to 1.5 L / h.

[0021] During the first coprecipitation reaction of this invention, the flow rate of the ternary mixed salt solution is 8 L / h to 10 L / h, for example, it can be 8 L / h, 9 L / h or 10 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] In the first coprecipitation reaction of the present invention, the flow rate of the precipitant solution is 3L / h to 5L / h, for example, it can be 3L / h, 4L / h or 5L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] During the first coprecipitation reaction of this invention, the flow rate of the complexing agent solution is 1 L / h to 1.5 L / h, for example, it can be 1 L / h, 1.1 L / h, 1.2 L / h, 1.3 L / h, 1.4 L / h or 1.5 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, during the second coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8 L / h to 10 L / h, the flow rate of the precipitant solution is 3 L / h to 5 L / h, and the flow rate of the complexing agent solution is 1 L / h to 1.5 L / h.

[0025] In the second coprecipitation reaction of this invention, the flow rate of the ternary mixed salt solution is 8 L / h to 10 L / h, for example, it can be 8 L / h, 9 L / h or 10 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] In the second coprecipitation reaction of the present invention, the flow rate of the precipitant solution is 3L / h to 5L / h, for example, it can be 3L / h, 4L / h or 5L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] During the second coprecipitation reaction of this invention, the flow rate of the complexing agent solution is 1 L / h to 1.5 L / h, for example, it can be 1 L / h, 1.1 L / h, 1.2 L / h, 1.3 L / h, 1.4 L / h or 1.5 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, during the third coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8 L / h to 10 L / h, the flow rate of the precipitant solution is 1 L / h to 3 L / h, the flow rate of the complexing agent solution is 1.5 L / h to 2 L / h, and the flow rate of the seed crystal solution is 0.9 L / h to 9 L / h.

[0029] This invention reduces the flow rate of the precipitant solution during the third coprecipitation reaction, thereby lowering the pH value during the third coprecipitation reaction, which is beneficial to the stable growth of the ternary precursor. Moreover, in combination with the appropriate increase of the complexing agent concentration and the addition of the seed solution, it is beneficial to effectively reduce the particle size distribution range of the large-particle-size ternary precursor.

[0030] In the third coprecipitation reaction of this invention, the flow rate of the ternary mixed salt solution is 8 L / h to 10 L / h, for example, it can be 8 L / h, 9 L / h or 10 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] In the third coprecipitation reaction of the present invention, the flow rate of the precipitant solution is 1L / h to 3L / h, for example, it can be 1L / h, 2L / h or 3L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] During the third coprecipitation reaction of this invention, the flow rate of the complexing agent solution is 1.5 L / h to 2 L / h, for example, it can be 1.5 L / h, 1.6 L / h, 1.8 L / h, 1.9 L / h or 2 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] During the third coprecipitation reaction of this invention, the flow rate of the seed solution is 0.9 L / h to 9 L / h, for example, it can be 0.9 L / h, 1 L / h, 3 L / h, 5 L / h, 6 L / h, 8 L / h or 9 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, the first coprecipitation reaction, the second coprecipitation reaction, and the third coprecipitation reaction are stirred independently at a speed of 150 r / min to 300 r / min, for example, 150 r / min, 160 r / min, 200 r / min, 210 r / min, 240 r / min, 250 r / min, 270 r / min, 280 r / min, or 300 r / min, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] Furthermore, the stirring speeds of the first coprecipitation reaction, the second coprecipitation reaction, and the third coprecipitation reaction are gradually reduced.

[0036] As a preferred embodiment of the dynamic adjustment method of the present invention, the dynamic adjustment method includes the following steps:

[0037] (1) A ternary mixed salt solution, a precipitant solution and a complexing agent solution are mixed in parallel in a bottom solution with a pH value of 11~12 and a complexing agent concentration of 5g / L~8g / L to carry out the first coprecipitation reaction, and a seed solution with a particle size D50 of 3μm~5μm and a solid content of 100g / L~200g / L is obtained.

[0038] During the first coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10L / h, the flow rate of the precipitant solution is 3L / h~5L / h, the flow rate of the complexing agent solution is 1L / h~1.5L / h, and the stirring speed is 150r / min~300r / min;

[0039] (2) A ternary mixed salt solution, a precipitant solution and a complexing agent solution are mixed in parallel in a base solution with a pH of 11-12 and a complexing agent concentration of 5 g / L-8 g / L to carry out a second coprecipitation reaction; when the second coprecipitation reaction reaches a particle size D50 of 7 μm-10 μm, the seed solution described in step (1) is additionally introduced in parallel, and a third coprecipitation reaction is carried out to the target particle size to obtain a ternary precursor;

[0040] During the second coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10 L / h, the flow rate of the precipitant solution is 3L / h~5L / h, the flow rate of the complexing agent solution is 1L / h~1.5L / h, and the stirring speed is 150r / min~300r / min;

[0041] During the third coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10L / h, the flow rate of the precipitant solution is 1L / h~3L / h, the flow rate of the complexing agent solution is 1.5L / h~2L / h, the flow rate of the seed crystal solution is 0.9L / h~9L / h, and the stirring speed is 150r / min~300r / min.

[0042] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] This invention utilizes seed crystals with a specific particle size (D50) to provide a unified initial template for precursor particle growth. This transforms disordered homogeneous nucleation in the reaction system into ordered heterogeneous nucleation, allowing metal ions to preferentially deposit on the seed crystal surface. This avoids the disordered formation of new nuclei caused by fluctuations in local supersaturation, thereby eliminating initial particle size differences caused by varying nucleation time differences. The seed crystal solution with a specific solid content precisely controls the number density of seed crystals in the reaction system. This ensures that the total amount of seed crystals is sufficient to consume the system's supersaturation to suppress new nuclei formation, while also guaranteeing that each seed crystal has a uniform growth space. This ensures that the deposition rate of metal ions on each seed crystal surface is consistent, avoiding growth rate imbalances caused by too many or too few seed crystals. Consequently, precursor particles grow synchronously from nearly identical initial states, reducing small particle residue and abnormal growth of large particles, ultimately achieving an effective reduction in the particle size distribution range of large-diameter ternary precursors. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] To clearly illustrate the technical solution of the present invention, the target particle size in the following examples and comparative examples refers to a particle size D50 of 15 μm; the ternary mixed salt in the ternary mixed salt solution is nickel sulfate, cobalt sulfate and manganese sulfate, and the total concentration of nickel sulfate, cobalt sulfate and manganese sulfate is 2 mol / L, and the molar ratio of nickel, cobalt and manganese is 8:1:1.

[0047] Example 1

[0048] This embodiment provides a method for dynamically adjusting the particle size distribution of large particles in a ternary precursor. The dynamic adjustment method includes the following steps:

[0049] (1) A ternary mixed salt solution, a sodium hydroxide solution with a mass concentration of 30 wt%, and ammonia solution with a mass concentration of 15 wt% were mixed in parallel in a bottom solution with a pH value of 11.5 and an ammonia concentration of 6 g / L to carry out the first coprecipitation reaction, and a seed solution with a particle size D50 of 4 μm and a solid content of 150 g / L was obtained.

[0050] During the first coprecipitation reaction, the flow rate of the ternary mixed salt solution was 9 L / h, the flow rate of the sodium hydroxide solution was 4 L / h, the flow rate of the ammonia solution was 1.2 L / h, and the stirring speed was 250 r / min.

[0051] (2) A ternary mixed salt solution, a sodium hydroxide solution with a mass concentration of 30 wt%, and ammonia solution with a mass concentration of 15 wt% are mixed in parallel in a base solution with a pH value of 11.5 and an ammonia concentration of 6 g / L to carry out a second coprecipitation reaction; when the second coprecipitation reaction reaches a particle size D50 of 8 μm, the seed solution described in step (1) is additionally introduced in parallel, and a third coprecipitation reaction is carried out to the target particle size to obtain a ternary precursor;

[0052] During the second coprecipitation reaction, the flow rate of the ternary mixed salt solution was 9 L / h, the flow rate of the sodium hydroxide solution was 4 L / h, the flow rate of the ammonia solution was 1.2 L / h, and the stirring speed was 200 r / min.

[0053] During the third coprecipitation reaction, the flow rate of the ternary mixed salt solution was 9 L / h, the flow rate of the precipitant solution was 2 L / h, the flow rate of the complexing agent solution was 1.8 L / h, the flow rate of the seed crystal solution was 4 L / h, and the stirring speed was 150 r / min.

[0054] Example 2

[0055] This embodiment provides a method for dynamically adjusting the particle size distribution of large particles in a ternary precursor. The dynamic adjustment method includes the following steps:

[0056] (1) A ternary mixed salt solution, a sodium hydroxide solution with a mass concentration of 20 wt%, and ammonia solution with a mass concentration of 10 wt% were mixed in parallel in a bottom solution with a pH value of 11 and an ammonia concentration of 5 g / L to carry out the first coprecipitation reaction, and a seed solution with a particle size D50 of 3 μm and a solid content of 100 g / L was obtained.

[0057] During the first coprecipitation reaction, the flow rate of the ternary mixed salt solution was 8 L / h, the flow rate of the sodium hydroxide solution was 3 L / h, the flow rate of the ammonia solution was 1 L / h, and the stirring speed was 200 r / min.

[0058] (2) A ternary mixed salt solution, a sodium hydroxide solution with a mass concentration of 20 wt%, and ammonia solution with a mass concentration of 10 wt% are mixed in parallel in a base solution with a pH value of 11 and an ammonia concentration of 5 g / L to carry out a second coprecipitation reaction; when the second coprecipitation reaction reaches a particle size D50 of 7 μm, the seed solution described in step (1) is additionally introduced in parallel, and a third coprecipitation reaction is carried out to the target particle size to obtain a ternary precursor;

[0059] During the second coprecipitation reaction, the flow rate of the ternary mixed salt solution was 8 L / h, the flow rate of the sodium hydroxide solution was 3 L / h, the flow rate of the ammonia solution was 1 L / h, and the stirring speed was 180 r / min.

[0060] During the third coprecipitation reaction, the flow rate of the ternary mixed salt solution was 8 L / h, the flow rate of the precipitant solution was 1 L / h, the flow rate of the complexing agent solution was 1.5 L / h, the flow rate of the seed crystal solution was 0.9 L / h, and the stirring speed was 150 r / min.

[0061] Example 3

[0062] This embodiment provides a method for dynamically adjusting the particle size distribution of large particles in a ternary precursor. The dynamic adjustment method includes the following steps:

[0063] (1) A ternary mixed salt solution, a sodium hydroxide solution with a mass concentration of 40wt%, and ammonia solution with a mass concentration of 20wt% were mixed in parallel in a bottom solution with a pH value of 12 and an ammonia concentration of 8g / L to carry out the first coprecipitation reaction, and a seed solution with a particle size D50 of 5μm and a solid content of 200g / L was obtained.

[0064] During the first coprecipitation reaction, the flow rate of the ternary mixed salt solution was 10 L / h, the flow rate of the sodium hydroxide solution was 5 L / h, the flow rate of the ammonia solution was 1.5 L / h, and the stirring speed was 300 r / min.

[0065] (2) A ternary mixed salt solution, a sodium hydroxide solution with a mass concentration of 40 wt%, and ammonia solution with a mass concentration of 20 wt% are mixed in parallel in a base solution with a pH value of 12 and an ammonia concentration of 8 g / L to carry out a second coprecipitation reaction; when the second coprecipitation reaction reaches a particle size D50 of 10 μm, the seed solution described in step (1) is additionally introduced in parallel, and a third coprecipitation reaction is carried out to the target particle size to obtain a ternary precursor;

[0066] During the second coprecipitation reaction, the flow rate of the ternary mixed salt solution was 10 L / h, the flow rate of the sodium hydroxide solution was 5 L / h, the flow rate of the ammonia solution was 1.5 L / h, and the stirring speed was 200 r / min.

[0067] During the third coprecipitation reaction, the flow rate of the ternary mixed salt solution was 10 L / h, the flow rate of the precipitant solution was 3 L / h, the flow rate of the complexing agent solution was 2 L / h, the flow rate of the seed crystal solution was 9 L / h, and the stirring speed was 150 r / min.

[0068] Example 4

[0069] This embodiment provides a method for dynamically adjusting the particle size distribution of large particles in a ternary precursor. The dynamic adjustment method includes the following steps:

[0070] (1) A ternary mixed salt solution, a sodium hydroxide solution with a mass concentration of 30 wt%, and ammonia solution with a mass concentration of 15 wt% were mixed in parallel in a bottom solution with a pH value of 11.5 and an ammonia concentration of 6 g / L to carry out the first coprecipitation reaction, and a seed solution with a particle size D50 of 4 μm and a solid content of 150 g / L was obtained.

[0071] During the first coprecipitation reaction, the flow rate of the ternary mixed salt solution was 9 L / h, the flow rate of the sodium hydroxide solution was 4 L / h, the flow rate of the ammonia solution was 1.2 L / h, and the stirring speed was 250 r / min.

[0072] (2) A ternary mixed salt solution, a sodium hydroxide solution with a mass concentration of 30 wt%, and ammonia solution with a mass concentration of 15 wt% are mixed in parallel in a base solution with a pH value of 11.5 and an ammonia concentration of 6 g / L to carry out a second coprecipitation reaction; when the second coprecipitation reaction reaches a particle size D50 of 8 μm, the seed solution described in step (1) is additionally introduced in parallel, and a third coprecipitation reaction is carried out to the target particle size to obtain a ternary precursor;

[0073] During the second coprecipitation reaction, the flow rate of the ternary mixed salt solution was 9 L / h, the flow rate of the sodium hydroxide solution was 4 L / h, the flow rate of the ammonia solution was 1.2 L / h, and the stirring speed was 200 r / min.

[0074] During the third coprecipitation reaction, the flow rate of the ternary mixed salt solution was 9 L / h, the flow rate of the precipitant solution was 4 L / h, the flow rate of the complexing agent solution was 1.2 L / h, the flow rate of the seed crystal solution was 4 L / h, and the stirring speed was 150 r / min.

[0075] Comparative Example 1

[0076] This comparative example provides a method for dynamically adjusting the particle size distribution of large ternary precursor particles. Except for the particle size D50 of the seed solution being 2 μm, the rest is the same as in Example 1.

[0077] Comparative Example 2

[0078] This comparative example provides a method for dynamically adjusting the particle size distribution of large ternary precursor particles. Except for the particle size D50 of the seed solution being 6 μm, the rest is the same as in Example 1.

[0079] Comparative Example 3

[0080] This comparative example provides a method for dynamically adjusting the particle size distribution of large ternary precursor particles. Except for the solid content of the seed solution being 80 g / L, everything else is the same as in Example 1.

[0081] Comparative Example 4

[0082] This comparative example provides a method for dynamically adjusting the particle size distribution of large ternary precursor particles. Except for the solid content of the seed solution being 240 g / L, everything else is the same as in Example 1.

[0083] Comparative Example 5

[0084] This comparative example provides a method for dynamically adjusting the particle size distribution of large particles in a ternary precursor. The dynamic adjustment method includes the following steps:

[0085] A ternary mixed salt solution, a 30wt% sodium hydroxide solution, and a 15wt% ammonia solution were co-mixed in a base solution with a pH of 11.5 and an ammonia concentration of 6 g / L, and a co-precipitation reaction was carried out to the target particle size to obtain a ternary precursor.

[0086] During the coprecipitation reaction, the flow rate of the ternary mixed salt solution was 9 L / h, the flow rate of the sodium hydroxide solution was 4 L / h, the flow rate of the ammonia solution was 1.2 L / h, and the stirring speed was 150 r / min.

[0087] Performance Characterization

[0088] The particle size distribution of the ternary precursors obtained in the above embodiments and comparative examples was measured. The span was defined as (D90-D10) / D50. The smaller the span value, the narrower the particle size distribution, and the larger the span value, the wider the particle size distribution. The results are shown in Table 1.

[0089] Table 1

[0090]

[0091] As can be seen from Examples 1 to 3 in Table 1, the dynamic adjustment method for the particle size distribution of large ternary precursors provided by the present invention can effectively narrow the particle size distribution, and Example 1, which corresponds to the middle value of the numerical range of the claims, has the best effect.

[0092] A comparison of Comparative Examples 1 and 2 with Example 1 shows that only by using seed crystals with a specific particle size D50 can the particle size distribution of the ternary precursor be effectively narrowed. This is because using only seed crystals with excessively small particle sizes leads to an excessive number of seed crystals, causing competition for growth resources and resulting in an unbalanced deposition rate; while using only seed crystals with excessively large particle sizes results in an insufficient number of seed crystals, which cannot fully consume the supersaturation of the system and easily leads to the disordered generation of new nuclei, both of which result in a wider particle size distribution.

[0093] Comparison of Comparative Examples 3 and 4 with Example 1 shows that only by using a seed solution with a specific solid content can the particle size distribution be precisely controlled. When using a seed solution with too low a solid content, the total amount of seeds is insufficient to suppress the formation of new nuclei; when using a seed solution with too high a solid content, the excessive number of seeds leads to insufficient growth space. Both will cause an imbalance in the growth rate, resulting in a wider particle size distribution.

[0094] As can be seen from the comparison between Comparative Example 5 and Example 1, the presence of seed crystals is a necessary condition for narrowing the particle size distribution of the ternary precursor. This is because, without a seed crystal solution, the reaction system relies entirely on disordered homogeneous nucleation, and the differences in initial particle size caused by different nucleation time differences cannot be eliminated, ultimately resulting in an extremely wide particle size distribution.

[0095] A comparison between Example 4 and Example 1 shows that dynamic adjustment of pH value and complexing agent concentration is crucial for optimizing particle size distribution. Without adjusting pH value and complexing agent concentration, uniform deposition of metal ions on the seed crystal surface cannot be guaranteed, resulting in a slightly poorer particle size distribution narrowing effect.

[0096] In summary, this invention uses seed crystals with a specific particle size (D50) to provide a unified initial template for precursor particle growth. This transforms disordered homogeneous nucleation in the reaction system into ordered heterogeneous nucleation, allowing metal ions to preferentially deposit on the seed crystal surface. This avoids the disordered formation of new nuclei caused by local supersaturation fluctuations, thereby eliminating the initial particle size differences caused by different nucleation time differences. The seed crystal solution with a specific solid content can precisely control the number density of seed crystals in the reaction system. This ensures that the total amount of seed crystals is sufficient to consume the system's supersaturation to inhibit new nucleation, while also guaranteeing that each seed crystal has a uniform growth space. This ensures that the deposition rate of metal ions on the surface of each seed crystal is consistent, avoiding growth rate imbalances caused by too many or too few seed crystals. As a result, precursor particles grow synchronously from nearly identical initial states, reducing the phenomenon of small particle residue and abnormal growth of large particles, ultimately achieving an effective reduction in the particle size distribution range of large-diameter ternary precursors.

[0097] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for dynamically adjusting the particle size distribution of large particles in a ternary precursor, characterized in that, The dynamic adjustment method includes: (1) A ternary mixed salt solution, a precipitant solution and a complexing agent solution are mixed in parallel in the bottom liquid to carry out the first coprecipitation reaction, and a seed solution with a particle size D50 of 3μm~5μm and a solid content of 100g / L~200g / L is obtained; (2) The ternary mixed salt solution, precipitant solution and complexing agent solution are mixed in parallel in the bottom liquid to carry out the second coprecipitation reaction; when the second coprecipitation reaction reaches the particle size D50 of 7μm~10μm, the seed solution described in step (1) is additionally introduced in parallel, and the third coprecipitation reaction is carried out to the target particle size to obtain the ternary precursor.

2. The dynamic adjustment method according to claim 1, characterized in that, The precipitant solution comprises a sodium hydroxide solution with a mass concentration of 20wt% to 40wt%.

3. The dynamic adjustment method according to claim 1, characterized in that, The complexing agent solution includes ammonia water with a mass concentration of 10wt% to 20wt%.

4. The dynamic adjustment method according to claim 1, characterized in that, The ternary mixed salt solution contains nickel salt, cobalt salt and manganese salt; Preferably, the total concentration of nickel salt, cobalt salt and manganese salt in the ternary mixed salt solution is 2 mol / L to 2.5 mol / L.

5. The dynamic adjustment method according to claim 4, characterized in that, The nickel salt includes any one or a combination of at least two of nickel sulfate, nickel chloride, or nickel nitrate. Preferably, the cobalt salt comprises any one or a combination of at least two of cobalt sulfate, cobalt chloride, or cobalt nitrate; Preferably, the manganese salt includes any one or a combination of at least two of manganese sulfate, manganese chloride, or manganese nitrate.

6. The dynamic adjustment method according to any one of claims 1 to 5, characterized in that, During the first coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10 L / h, the flow rate of the precipitant solution is 3L / h~5L / h, and the flow rate of the complexing agent solution is 1L / h~1.5L / h.

7. The dynamic adjustment method according to claim 1, characterized in that, During the second coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10 L / h, the flow rate of the precipitant solution is 3L / h~5L / h, and the flow rate of the complexing agent solution is 1L / h~1.5L / h.

8. The dynamic adjustment method according to claim 1, characterized in that, During the third coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10 L / h, the flow rate of the precipitant solution is 1L / h~3L / h, the flow rate of the complexing agent solution is 1.5L / h~2L / h, and the flow rate of the seed crystal solution is 0.9L / h~9L / h.

9. The dynamic adjustment method according to any one of claims 6 to 9, characterized in that, The first coprecipitation reaction, the second coprecipitation reaction, and the third coprecipitation reaction were stirred independently at a speed of 150 r / min to 300 r / min.

10. The dynamic adjustment method according to claim 1, characterized in that, The dynamic adjustment method includes the following steps: (1) A ternary mixed salt solution, a precipitant solution and a complexing agent solution are mixed in parallel in a bottom solution with a pH value of 11~12 and a complexing agent concentration of 5g / L~8g / L to carry out the first coprecipitation reaction, and a seed solution with a particle size D50 of 3μm~5μm and a solid content of 100g / L~200g / L is obtained. During the first coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10L / h, the flow rate of the precipitant solution is 3L / h~5L / h, the flow rate of the complexing agent solution is 1L / h~1.5L / h, and the stirring speed is 150r / min~300r / min; (2) A ternary mixed salt solution, a precipitant solution and a complexing agent solution are mixed in parallel in a base solution with a pH of 11-12 and a complexing agent concentration of 5 g / L-8 g / L to carry out a second coprecipitation reaction; when the second coprecipitation reaction reaches a particle size D50 of 7 μm-10 μm, the seed solution described in step (1) is additionally introduced in parallel, and a third coprecipitation reaction is carried out to the target particle size to obtain a ternary precursor; During the second coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10 L / h, the flow rate of the precipitant solution is 3L / h~5L / h, the flow rate of the complexing agent solution is 1L / h~1.5L / h, and the stirring speed is 150r / min~300r / min; During the third coprecipitation reaction, the flow rate of the ternary mixed salt solution is 8~10L / h, the flow rate of the precipitant solution is 1L / h~3L / h, the flow rate of the complexing agent solution is 1.5L / h~2L / h, the flow rate of the seed crystal solution is 0.9L / h~9L / h, and the stirring speed is 150r / min~300r / min.

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