Small particle ternary precursor, its preparation method and application

Abstract

This invention discloses a small-particle ternary precursor, its preparation method, and its application. The method includes the following steps: Under an inert atmosphere, a mixture of a ternary liquid, ammonia, liquid alkali, and a reaction base liquid is used as the reaction system for a first-stage granulation reaction to obtain a first reaction core with a particle size of 0.6 μm ≤ D50 ≤ 1.1 μm. The parameters of the first-stage granulation reaction system are adjusted to conduct a second-stage granulation reaction to obtain a second reaction core with a particle size of 1.1 μm < D50 ≤ 2.8 μm. The reaction base liquid contains water, ammonia, and liquid alkali, and the ternary liquid contains nickel salt, cobalt salt, and manganese salt. The parameters of the second-stage granulation reaction system are adjusted to conduct a first-stage growth reaction to obtain a third reaction core with a particle size of 2.8 μm < D50 ≤ 3.2 μm. Air is introduced to conduct a second-stage growth reaction to obtain the small-particle ternary precursor. This application improves the tap density of the material during the early growth process and increases the specific surface area by controlling the oxidation level in the later growth stage, thus simultaneously improving the tap density and specific surface area of ​​the ternary precursor.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and in particular to a small-particle ternary precursor, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries are widely used in electric vehicles, power tools, 3C products and other fields due to their advantages such as stable voltage, high capacity, high energy density, low self-discharge, stable cycle performance, low consumption and environmental friendliness. With the development of technology, the requirements for battery energy density and safety are getting higher and higher. Ternary materials have high reversible specific capacity, which can better meet the requirements of the increasing miniaturization and multifunctionality of electronic products.

[0003] The morphology, particle size, specific surface area, tap density, and other physicochemical properties of ternary precursors largely determine the performance of ternary cathode materials. However, in related technologies, the energy density and charge-discharge performance of ternary lithium-ion batteries are insufficient because it is difficult to simultaneously improve the tap density and specific surface area of ​​ternary precursor materials.

[0004] Therefore, it is necessary to provide a scheme to simultaneously improve the tap density (TD) and specific surface area (BET) of ternary precursor materials. Summary of the Invention

[0005] In view of this, this application provides a small-particle ternary precursor, its preparation method and application, to solve the problem of how to simultaneously improve the tap density and specific surface area of ​​the ternary precursor.

[0006] To achieve the above technical objectives, this application adopts the following technical solution:

[0007] In a first aspect, this application provides a method for preparing a small-particle ternary precursor, comprising the following steps:

[0008] S1. Under an inert atmosphere, a mixture of ternary liquid, ammonia, liquid alkali, and reaction base liquid is used as the reaction system to carry out a first-stage granulation reaction to obtain a first reaction core with a particle size of 0.6μm≤D50≤1.1μm. The parameters of the first-stage granulation reaction system are adjusted and a second-stage granulation reaction is carried out to obtain a second reaction core with a particle size of 1.1μm<D50≤2.8μm. The reaction base liquid contains water, ammonia, and liquid alkali, and the ternary liquid contains nickel salt, cobalt salt, and manganese salt.

[0009] S2. Adjust the parameters of the two-stage granulation reaction system and carry out a first-stage growth reaction to obtain a third reaction nucleus with 2.8μm < D50 ≤ 3.2μm. Then, introduce air to carry out a second-stage growth reaction to the target particle size, thus obtaining a small-particle ternary precursor.

[0010] Preferably, in step S1, during the first granulation reaction, the concentration of ammonium ions in the reaction substrate is 1.5-2.0 g / L, the pH of the reaction substrate is 12.05-12.2, and the temperature of the reaction substrate is 65-70℃.

[0011] Preferably, in step S1, during the first stage of granulation reaction, the molar ratio of nickel salt, cobalt salt, and manganese salt in the ternary solution, based on metal ions, is (0.602-0.604):(0.0985-0.1025):(0.2935-0.2995), and the total concentration of metal ions in the ternary solution is 1.5-2.0 mol / L.

[0012] Preferably, in step S1, during the first stage of granulation reaction, the flow rate of the ternary liquid in the mixed solution is 95-100 L / h, the flow rate of ammonia is 1-7 L / h, the flow rate of liquid alkali is 36-38 L / h, and the stirring rate is 370-400 rpm.

[0013] Preferably, the step of adjusting the parameters of the first-stage granulation reaction system before carrying out the second-stage granulation reaction includes adjusting the ammonium ion concentration to 2.5-3.5 g / L, the pH to 11.7-11.95, and the stirring speed to 370-400 rpm.

[0014] Preferably, the step of adjusting the parameters of the two-stage granulation reaction system and then carrying out a first-stage growth reaction includes adjusting the flow rate of the ternary solution to 300-350 L / h, the reaction pH to 11.4-11.6, the ammonium concentration to 3.5-4.5 g / L, and the stirring speed to 300-350 rpm.

[0015] Preferably, in the two-stage growth reaction, the total pressure of the inert gas and air is 1-1.5 MPa, and the partial pressure of air is 0.5-0.8 MPa.

[0016] Preferably, in step S2, the target particle size is 3.15μm≤D50≤3.2μm.

[0017] Secondly, this application provides a method for preparing small-particle ternary precursors.

[0018] Thirdly, this application provides a battery cathode material, which is formed by sintering small-particle ternary precursors with lithium salt.

[0019] The beneficial effects of this application are as follows: The ternary precursor of this application has the advantages of large specific surface area and high tap density; This application improves the material tapping by using low concentration of ammonium ions and high pH during the early growth process, and improves the specific surface area by controlling air oxidation in the later growth stage, which is conducive to preparing a medium-nickel small particle ternary precursor with slender primary particles, small size and high overall consistency. Attached Figure Description

[0020] Figure 1 This is an electron microscope image of the small-particle ternary precursor obtained in Example 1. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] This application provides a method for preparing a small-particle ternary precursor, comprising the following steps:

[0023] S1. Under an inert atmosphere, a mixture of ternary liquid, ammonia, liquid alkali, and reaction base liquid is pumped into the reactor to carry out a first-stage granulation reaction to obtain the first reaction core. The reaction system is adjusted to continue the second-stage granulation reaction to obtain the second reaction core. The reaction base liquid contains water, ammonia, and liquid alkali, and the ternary liquid contains nickel salt, cobalt salt, and manganese salt. The particle size of the first reaction core is 0.6μm≤D50≤1.1μm, and the particle size of the second reaction core is 1.1μm<D50≤2.8μm.

[0024] S2. Adjust the reaction system and continue to pump a mixture of ternary liquid, ammonia, liquid alkali and reaction base liquid into the reactor to carry out a first-stage growth reaction to obtain the third reaction nucleus. Then, air is introduced to carry out a second-stage growth reaction. After the target particle size range is reached, the reaction is stopped to obtain small-particle ternary precursors. The particle size of the third reaction nucleus is 2.8μm < D50 ≤ 3.2μm.

[0025] In some embodiments, in step S1, the ammonium concentration of the reaction substrate is 1.5-2.0 g / L, the pH is 12.05-12.2, and the temperature is 65-70°C.

[0026] In some embodiments, in step S1, the molar ratio of nickel salt, cobalt salt, and manganese salt in the ternary solution, calculated as metal ions, is (0.602-0.604):(0.0985-0.1025):(0.2935-0.2995), and the total concentration of metal ions in the ternary solution is 1.5-2.0 mol / L. The mass concentrations of ammonia and liquid alkali are 14-18% and 32%, respectively.

[0027] In some embodiments, the nickel salt is nickel sulfate, the cobalt salt is cobalt sulfate, and the manganese salt is manganese sulfate. S1 includes steps S11. preparation of the ternary solution, S12. preparation of the base solution, and S13. granulation stage.

[0028] Specifically, before the first granulation reaction, water, ammonia, and liquid alkali are added to the reactor to form a reaction base liquid and an inert gas is introduced. The temperature is then raised to 65-70°C. Then, a mixture of ternary liquid, ammonia, and liquid alkali is pumped into the reactor to enter the first granulation stage. The pH and stirring rate are controlled to stabilize the reaction particle size.

[0029] In some embodiments, in the mixture of the first-stage granulation reaction in step S1, the flow rate of the ternary liquid is 95-100 L / h, the flow rate of ammonia is 1-7 L / h, the flow rate of liquid alkali is 36-38 L / h, and the stirring rate is 370-400 rpm until the particle size of the obtained particles is 0.6 μm ≤ D50 ≤ 1.1 μm. The first-stage granulation stage is then stopped, and the reaction conditions are adjusted to carry out the second-stage granulation.

[0030] In some embodiments, in the two-stage granulation reaction of step S1, the ammonium concentration is 2.5-3.5 g / L, the pH is 11.7-11.95, the stirring rate is 370-400 rpm, and after the reactor is full, it enters a thickener for circulation and concentration until the particle size of the obtained particles is 1.1 μm < D50 ≤ 2.8 μm. The two-stage granulation stage is then stopped, and the reaction conditions are adjusted to enter the first-stage growth stage.

[0031] In some embodiments, in the first stage of growth reaction in step S2, the flow rate of the ternary solution is 300-350 L / h, the reaction pH is 11.4-11.6, the ammonium concentration is 3.5-4.5 g / L, the stirring rate is 300-350 rpm, and after the reactor is full, it enters a thickener for circulation and concentration until the particle size of the obtained particles is 2.8 μm < D50 ≤ 3.2 μm, and then enters the second stage of growth reaction.

[0032] In some embodiments, during the two-stage growth reaction in step S2, the total pressure of the inert gas and air is 1-1.5 MPa, the partial pressure of air is 0.5-0.8 MPa, and the reaction continues until the resulting particles reach the target particle size.

[0033] In some embodiments, in step S2, the target particle size is 3.15μm≤D50≤3.2μm.

[0034] The small-particle ternary precursor obtained by the preparation method of this application has a large specific surface area, high tap density, and the primary particles are slender and small in size, while the secondary particles are loose and porous, with high overall consistency. When preparing cathode materials, it can effectively improve the electrochemical performance of the cathode materials.

[0035] This application provides a battery cathode material, which is formed by sintering small-particle ternary precursors and lithium salts.

[0036] The following specific embodiments further illustrate this solution.

[0037] Example 1

[0038] A method for preparing a small-particle ternary precursor includes the following steps:

[0039] S11. Preparation of ternary solution: Prepare a ternary solution with a total metal concentration of 1.5 mol / L by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in proportions of 60.4 mol% nickel, 10.05 mol% cobalt, and 29.55 mol% manganese.

[0040] S12. Preparation of the base solution: After purging nitrogen into the reactor for 30 minutes, pure water, ammonia and liquid alkali were added and heated to 65°C to obtain the reaction base solution. The ammonium concentration of the reaction base solution was measured to be 1.64 g / L, pH=12.08, and the temperature was 65°C.

[0041] S13. Granulation Stage: A mixture of ternary electrolyte, ammonia, and liquid alkali is pumped into the reactor containing the reaction base liquid at flow rates of 100 L / h, 6 L / h, and 38 L / h, respectively. The ammonium concentration in the reaction system is 1.66 g / L, the pH is 11.92, and the stirring rate is 370 rpm. After 2 hours of reaction, the particle size is measured to be D50 = 0.836 μm (first reaction core). Within 2 hours, the flow rates of ammonia and liquid alkali are gradually adjusted to maintain the ammonium concentration in the reaction system at 2.59 g / L, the pH at 11.84, and the stirring rate at 370 rpm. The reaction continues until the particle size D50 = 1.1 μm (second reaction core), completing the granulation stage.

[0042] S2. After the granulation stage, adjust the flow rates of the ternary solution, ammonia, and liquid alkali to 300 L / h, 13 L / h, and 100 L / h, respectively. The ammonium concentration in the reaction system is 3.68 g / L, the pH is 11.53, and the stirring rate is 300 rpm. After 45 h of reaction, the particle size D50 is measured to be 2.77 μm (third reaction nucleus). Air is then introduced into the reactor, with the total pressure of the inert gas and air controlled at 1.5 MPa and the partial pressure of air controlled at 0.5 MPa, until the particle size reaches 3.15 μm = D50, at which point the reaction is stopped. This yields the small-particle ternary precursor, and its electron micrograph is shown below. Figure 1 As shown.

[0043] Example 2

[0044] A method for preparing a small-particle ternary precursor includes the following steps:

[0045] S11. Preparation of ternary solution: Prepare a ternary solution with a total metal concentration of 1.5 mol / L by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in proportions of 60.4 mol% nickel, 10.05 mol% cobalt, and 29.55 mol% manganese.

[0046] S12. Preparation of the base solution: After purging nitrogen into the reactor for 30 minutes, pure water, ammonia and liquid alkali were added and heated to 65°C to obtain the reaction base solution. The ammonium concentration of the reaction base solution was measured to be 1.79 g / L, pH=12.12, and the temperature was 65°C.

[0047] S13. Granulation Stage: A mixture of ternary solvent, ammonia, and liquid alkali is pumped into the reactor containing the reaction base liquid at flow rates of 100 L / h, 5 L / h, and 37 L / h, respectively. The ammonium concentration in the reaction system is 1.86 g / L, the pH is 11.73, and the stirring rate is 370 rpm. After 2 hours of reaction, the particle size is measured to be D50 = 0.918 μm (first reaction core). Within 2 hours, the flow rates of ammonia and liquid alkali are gradually adjusted to maintain the ammonium concentration in the reaction system at 3.1 g / L, the pH at 11.91, and the stirring rate at 370 rpm. The reaction continues until the particle size D50 = 1.1 μm (second reaction core), completing the granulation stage.

[0048] S2. After the granulation stage, adjust the flow rates of the ternary solution, ammonia, and liquid alkali to 300 L / h, 13 L / h, and 100 L / h, respectively. The ammonium concentration in the reaction system is 3.52 g / L, the pH is 11.42, and the stirring rate is 300 rpm. After 40 h of reaction, the particle size is measured to be D50 = 2.82 μm (third reaction nucleus). Air is introduced into the reactor, and the total pressure of the inert gas and air is controlled at 1.5 MPa, and the partial pressure of air is controlled at 0.6 MPa. The reaction is stopped when the particle size reaches 3.2 μm = D50, thus obtaining the small-particle ternary precursor.

[0049] Example 3

[0050] A method for preparing a small-particle ternary precursor includes the following steps:

[0051] S11. Preparation of ternary solution: Prepare a ternary solution with a total metal concentration of 1.5 mol / L by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in proportions of 60.4 mol% nickel, 10.05 mol% cobalt, and 29.55 mol% manganese.

[0052] S12. Preparation of the base solution: After purging nitrogen into the reactor for 30 minutes, pure water, ammonia and liquid alkali were added and heated to 65°C to obtain the reaction base solution. The ammonium concentration of the reaction base solution was measured to be 1.69 g / L, pH=12.04, and the temperature was 65°C.

[0053] S13. Granulation Stage: A mixture of ternary solution, ammonia, and liquid alkali is pumped into the reactor containing the reaction base liquid at flow rates of 100 L / h, 4 L / h, and 38 L / h, respectively. The ammonium concentration in the reaction system is 1.57 g / L, the pH is 12.06, and the stirring rate is 370 rpm. After 2 hours of reaction, the particle size is measured to be D50 = 0.756 μm (first reaction core). Within 2 hours, the flow rates of ammonia and liquid alkali are gradually adjusted to maintain the ammonium concentration in the reaction system at 2.7 g / L, the pH at 11.84, and the stirring rate at 370 rpm. The reaction continues until the particle size D50 = 1.1 μm (second reaction core), completing the granulation stage.

[0054] S2. After the granulation stage, adjust the flow rates of the ternary solution, ammonia, and liquid alkali to 300 L / h, 13 L / h, and 100 L / h, respectively. The ammonium concentration in the reaction system is 4.2 g / L, the pH is 11.55, and the stirring rate is 300 rpm. After 50 h of reaction, the particle size is measured to be D50 = 2.751 μm (third reaction nucleus). Air is introduced into the reactor, and the total pressure of the inert gas and air is controlled at 1.5 MPa, and the partial pressure of air is controlled at 0.6 MPa. The reaction is stopped when the particle size reaches 3.15 μm = D50, thus obtaining the small-particle ternary precursor.

[0055] Example 4

[0056] A method for preparing a small-particle ternary precursor includes the following steps:

[0057] S11. Preparation of ternary solution: Prepare a ternary solution with a total metal concentration of 2 mol / L by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in proportions of 60.4 mol% nickel, 10.05 mol% cobalt, and 29.55 mol% manganese.

[0058] S12. Preparation of the base solution: After purging nitrogen into the reactor for 30 minutes, pure water, ammonia and liquid alkali were added and heated to 70°C to obtain the reaction base solution. The ammonium concentration of the reaction base solution was measured to be 1.84 g / L, pH=12.06, and the temperature was 70°C.

[0059] S13. Granulation Stage: A mixture of ternary solvent, ammonia, and liquid alkali is pumped into the reactor containing the reaction base liquid at flow rates of 100 L / h, 6 L / h, and 38 L / h, respectively. The ammonium concentration in the reaction system is 1.92 g / L, the pH is 12.1, and the stirring rate is 370 rpm. After 2 hours of reaction, the particle size is measured to be D50 = 0.748 μm (first reaction core). Within 2 hours, the flow rates of ammonia and liquid alkali are gradually adjusted to maintain the ammonium concentration in the reaction system at 2.72 g / L, the pH at 11.91, and the stirring rate at 370 rpm. The reaction continues until the particle size D50 = 1.1 μm (second reaction core), completing the granulation stage.

[0060] S2. After the granulation stage, adjust the flow rates of the ternary solution, ammonia, and liquid alkali to 300 L / h, 13 L / h, and 100 L / h, respectively. The ammonium concentration in the reaction system is 3.84 g / L, the pH is 11.62, and the stirring rate is 300 rpm. After 55 h of reaction, the particle size is measured to be D50 = 2.871 μm (third reaction nucleus). Air is introduced into the reactor, and the total pressure of the inert gas and air is controlled at 1.5 MPa, and the partial pressure of air is controlled at 0.5 MPa. The reaction is stopped when the particle size reaches 3.15 μm = D50, thus obtaining the small-particle ternary precursor.

[0061] Example 5

[0062] A method for preparing a small-particle ternary precursor includes the following steps:

[0063] S11. Preparation of ternary solution: Prepare a ternary solution with a total metal concentration of 2 mol / L by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in proportions of 60.4 mol% nickel, 10.05 mol% cobalt, and 29.55 mol% manganese.

[0064] S12. Preparation of the base solution: After purging nitrogen into the reactor for 30 minutes, pure water, ammonia and liquid alkali were added and heated to 70°C to obtain the reaction base solution. The ammonium concentration of the reaction base solution was measured to be 1.95 g / L, pH=12.12, and the temperature was 70°C.

[0065] S13. Granulation Stage: A mixture of ternary electrolyte, ammonia, and liquid alkali is pumped into the reactor containing the reaction base liquid at flow rates of 100 L / h, 6 L / h, and 37 L / h, respectively. The ammonium concentration in the reaction system is 1.92 g / L, the pH is 12.06, and the stirring rate is 370 rpm. After 2 hours of reaction, the particle size is measured to be D50 = 1.089 μm (first reaction nucleus). Within 2 hours, the flow rates of ammonia and liquid alkali are gradually adjusted to maintain the ammonium concentration in the reaction system at 3.2 g / L, the pH at 11.75, and the stirring rate at 370 rpm. The reaction continues until the particle size D50 = 1.1 μm (second reaction nucleus), completing the granulation stage.

[0066] S2. After the granulation stage, adjust the flow rates of the ternary solution, ammonia, and liquid alkali to 300 L / h, 13 L / h, and 100 L / h, respectively. The ammonium concentration in the reaction system is 3.8 g / L, the pH is 11.46, and the stirring rate is 300 rpm. After 40 h of reaction, the particle size is measured to be D50 = 2.862 μm (third reaction nucleus). Air is introduced into the reactor, and the total pressure of the inert gas and air is controlled at 1.5 MPa, and the partial pressure of air is controlled at 0.7 MPa. The reaction is stopped when the particle size reaches 3.15 μm = D50, thus obtaining the small-particle ternary precursor.

[0067] Example 6

[0068] A method for preparing a small-particle ternary precursor includes the following steps:

[0069] S11. Preparation of ternary solution: Prepare a ternary solution with a total metal concentration of 2 mol / L by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in proportions of 60.4 mol% nickel, 10.05 mol% cobalt, and 29.55 mol% manganese.

[0070] S12. Preparation of the base solution: After purging nitrogen into the reactor for 30 minutes, pure water, ammonia and liquid alkali were added and heated to 70°C to obtain the reaction base solution. The ammonium concentration of the reaction base solution was measured to be 1.84 g / L, pH=12.17, and the temperature was 70°C.

[0071] S13. Granulation Stage: A mixture of ternary solvent, ammonia, and liquid alkali is pumped into the reactor containing the reaction base liquid at flow rates of 100 L / h, 6 L / h, and 38 L / h, respectively. The ammonium concentration in the reaction system is 1.93 g / L, the pH is 12.13, and the stirring rate is 370 rpm. After 2 hours of reaction, the particle size is measured to be D50 = 0.814 μm (first reaction core). Within 2 hours, the flow rates of ammonia and liquid alkali are gradually adjusted to maintain the ammonium concentration in the reaction system at 3.15 g / L, the pH at 11.75, and the stirring rate at 370 rpm. The reaction continues until the particle size D50 = 1.1 μm (second reaction core), completing the granulation stage.

[0072] S2. After the granulation stage, adjust the flow rates of the ternary solution, ammonia, and liquid alkali to 300 L / h, 13 L / h, and 100 L / h, respectively. The ammonium concentration in the reaction system is 3.5 g / L, the pH is 11.44, and the stirring rate is 300 rpm. After reacting for 45 h, the particle size is measured to be D50 = 2.81 μm (third reaction nucleus). Air is introduced into the reactor, and the total pressure of the inert gas and air is controlled at 1.5 MPa, and the partial pressure of air is controlled at 0.6 MPa. The reaction is stopped when the particle size reaches 3.15 μm = D50, thus obtaining the small-particle ternary precursor.

[0073] Comparative Example 1

[0074] A method for preparing a ternary precursor includes the following steps:

[0075] S11. Preparation of ternary solution: Prepare a ternary solution with a total metal concentration of 1.5 mol / L by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in proportions of 60.4 mol% nickel, 10.05 mol% cobalt, and 29.55 mol% manganese.

[0076] S12. Preparation of the base solution: After purging nitrogen into the reactor for 30 minutes, pure water, ammonia and liquid alkali were added and heated to 70°C to obtain the reaction base solution. The ammonium concentration of the reaction base solution was measured to be 1.59 g / L, pH=12.06, and the temperature was 70°C.

[0077] S13. Granulation Stage: A mixture of ternary solvent, ammonia, and liquid alkali is pumped into the reactor containing the reaction base liquid at flow rates of 100 L / h, 6 L / h, and 38 L / h, respectively. The ammonium concentration in the reaction system is 1.63 g / L, the pH is 12.12, and the stirring rate is 370 rpm. After 2 hours of reaction, the particle size is measured to be D50 = 0.741 μm (first reaction core). Within 2 hours, the flow rates of ammonia and liquid alkali are gradually adjusted to maintain the ammonium concentration in the reaction system at 3.15 g / L, the pH at 11.75, and the stirring rate at 370 rpm. The reaction continues until the particle size D50 = 1.1 μm (second reaction core), completing the granulation stage.

[0078] S2. After the granulation stage, adjust the flow rates of the ternary solution, ammonia, and liquid alkali to 300 L / h, 13 L / h, and 100 L / h, respectively. The ammonium concentration in the reaction system is 3.5 g / L, the pH is 11.44, the stirring speed is 300 rpm, and no air is introduced. After 65 h of reaction, the particle size is measured to be D50 = 3.21 μm, thus obtaining the ternary precursor.

[0079] Comparative Example 2

[0080] A method for preparing a ternary precursor includes the following steps:

[0081] S11. Preparation of ternary solution: Prepare a ternary solution with a total metal concentration of 2.0 mol / L by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in proportions of 60.4 mol% nickel, 10.05 mol% cobalt, and 29.55 mol% manganese.

[0082] S12. Preparation of the base solution: After purging nitrogen into the reactor for 30 minutes, pure water, ammonia and liquid alkali were added and heated to 65°C to obtain the reaction base solution. The ammonium concentration of the reaction base solution was measured to be 1.69 g / L, pH=12.08, and the temperature was 65°C.

[0083] S13. Granulation Stage: A mixture of ternary solution, ammonia, and liquid alkali is pumped into the reactor containing the reaction base liquid at flow rates of 100 L / h, 4 L / h, and 38 L / h, respectively. The ammonium concentration in the reaction system is 1.67 g / L, the pH is 12.06, and the stirring rate is 370 rpm. After 2 hours of reaction, the particle size is measured to be D50 = 0.772 μm (first reaction core). Within 2 hours, the flow rates of ammonia and liquid alkali are gradually adjusted to maintain the ammonium concentration in the reaction system at 2.81 g / L, the pH at 11.84, and the stirring rate at 370 rpm. The reaction continues until the particle size D50 = 1.1 μm (second reaction core), completing the granulation stage.

[0084] S2. After the granulation stage, adjust the flow rates of the ternary solution, ammonia, and liquid alkali to 300 L / h, 13 L / h, and 100 L / h, respectively. The ammonium concentration in the reaction system is 4.2 g / L, the pH is 11.55, the stirring speed is 300 rpm, and no air is introduced. After 70 h of reaction, the particle size is measured to be D50 = 3.151 μm, thus obtaining the ternary precursor.

[0085] Testing and Evaluation

[0086] The tap density (TD) and specific surface area (BET) of the ternary precursors obtained from each embodiment and comparative example were tested, and the results are shown in Table 1.

[0087] Table 1 Test Results

[0088]

[0089] The above data shows that this application improves the material's tap density by using low concentrations of ammonium ions and high pH during the early growth stage, and increases the specific surface area by controlling air oxidation in the later growth stage. This facilitates the preparation of a ternary precursor with slender, small-sized, and highly uniform medium-nickel particles. The ternary precursor of this application has the advantages of large specific surface area and high tap density.

[0090] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a small-particle ternary precursor, characterized in that, Including the following steps: S1. Under an inert atmosphere, a mixture of a ternary liquid, ammonia, liquid alkali, and a reaction base liquid is used as the reaction system to carry out a first-stage granulation reaction to obtain a first reaction core with a particle size of 0.6μm≤D50≤1.1μm. The parameters of the first-stage granulation reaction system are adjusted and a second-stage granulation reaction is carried out to obtain a second reaction core with a particle size of 1.1μm<D50≤2.8μm. The reaction base liquid contains water, ammonia, and liquid alkali, and the ternary liquid contains nickel salt, cobalt salt, and manganese salt. S2. Adjust the parameters of the two-stage granulation reaction system and carry out a first-stage growth reaction to obtain a third reaction nucleus with 2.8μm < D50 ≤ 3.2μm. Then, introduce air to carry out a second-stage growth reaction to the target particle size, thus obtaining a small-particle ternary precursor. In step S1, during the first granulation reaction, the concentration of ammonium ions in the reaction substrate is 1.5-2.0 g / L, the pH of the reaction substrate is 12.05-12.2, and the temperature of the reaction substrate is 65-70℃. In step S1, during the first granulation reaction, the molar ratio of nickel salt, cobalt salt, and manganese salt in the ternary solution, based on metal ions, is (0.602-0.604):(0.0985-0.1025):(0.2935-0.2995), and the total concentration of metal ions in the ternary solution is 1.5-2.0 mol / L. In step S1, during the first granulation reaction, the flow rate of the ternary liquid in the mixture is 95-100 L / h, the flow rate of ammonia is 1-7 L / h, the flow rate of liquid alkali is 36-38 L / h, and the stirring rate is 370-400 rpm. The steps for adjusting the parameters of the first-stage granulation reaction system before carrying out the second-stage granulation reaction include adjusting the ammonium ion concentration to 2.5-3.5 g / L, the pH to 11.7-11.95, and the stirring speed to 370-400 rpm. The steps for adjusting the parameters of the two-stage granulation reaction system before carrying out the first-stage growth reaction include adjusting the flow rate of the ternary solution to 300-350 L / h, the reaction pH to 11.4-11.6, the ammonium concentration to 3.5-4.5 g / L, and the stirring speed to 300-350 rpm. In the two-stage growth reaction, the total pressure of the inert gas and air is 1-1.5 MPa, and the partial pressure of air is 0.5-0.8 MPa.

2. The method for preparing the small-particle ternary precursor according to claim 1, characterized in that, In step S2, the target particle size is 3.15μm≤D50≤3.2μm.

3. A small-particle ternary precursor obtained by the preparation method according to any one of claims 1-2.

4. A battery cathode material, characterized in that, It is formed by sintering the small-particle ternary precursor as described in claim 3 with lithium salt.

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