A method for batch production of high nickel, aluminum-doped precursors

Abstract

The present application relates to the technical field of lithium ion batteries, in particular to a high-nickel and aluminum-doped precursor intermittent preparation method, wherein a nickel-manganese binary salt solution and an aluminum salt solution are first configured; then pure water, a complexing agent and a precipitating agent are added into a reaction kettle to configure a bottom liquid; then inert gas is introduced into the reaction kettle; the stirring function of the reaction kettle is started, the nickel-manganese binary salt solution is added into the reaction kettle to obtain primary particles; after waiting for 10 hours of reaction, compressed air is introduced into the reaction kettle; then the aluminum salt solution is introduced into the reaction kettle to fill the loose state of the surface of the primary particles by introducing the aluminum salt, thereby forming a high-compaction and high-specific-surface positive electrode precursor material; finally, the slurry after reaction is aged, and the aged slurry is subjected to centrifugation, washing and drying, and finally the precursor powder is obtained. The present application can prepare a high-compaction and high-specific-surface positive electrode precursor material by using a coprecipitation method to prepare nickel-manganese hydroxide.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion batteries, and more particularly to a method for intermittent preparation of a high-nickel, aluminum-doped precursor. Background Technology

[0002] Precursors are key raw materials for the preparation of cathode materials. In the lithium battery cathode industry chain, the final performance of cathode materials will inherit the morphological and structural characteristics of their precursors. The quality of precursors (morphology, particle size, particle size distribution, specific surface area, impurity content, tap density, etc.) directly determines the physicochemical properties of cathode sintering products.

[0003] When applying for this invention, the applicant, after searching, discovered that a Chinese patent disclosed "A multilayer aluminum-doped nickel-cobalt-manganese precursor and its preparation method", application number "202110981619.5". This patent mainly involves adding ammonia water as the reaction base liquid to a reaction vessel, introducing nitrogen gas, starting stirring, and adding a metal salt mixture, precipitant, and complexing agent in a parallel flow to the reaction vessel until the particle size of the generated particles reaches the core particle size; introducing sodium aluminate solution to form an aluminum-doped nickel-cobalt-manganese hydroxide layer on the surface of the core; stopping the introduction of sodium aluminate solution to form an undoped nickel-cobalt-manganese hydroxide layer on the surface of the aluminum-doped nickel-cobalt-manganese hydroxide layer.

[0004] However, the precursor structure generated above is a coated structure. The thickness of the outer layer of hydroxide layer with a certain thickness needs to be considered when coating the nickel-cobalt-manganese core, which increases the difficulty of precursor preparation. In addition, a thicker outer layer will hinder the diffusion of lithium during the insertion and extraction process. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an intermittent preparation method for high-nickel, aluminum-doped precursors.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a method for intermittent preparation of a high-nickel, aluminum-doped precursor, comprising the following steps:

[0007] S1, Configuration containing Ni 2+ Mn 2+ Prepare a binary salt solution and a 0.1-2 mol / L aluminum salt solution;

[0008] S2. Add pure water, complexing agent, and precipitant to the reactor as the base liquid, and continuously introduce inert gas to maintain a stable flow rate for 3 hours to reduce the oxygen content in the reactor. During the process, control the temperature in the reactor between 40-65℃.

[0009] S3. Turn on the stirring function of the reactor and add Ni into the reactor. 2+ Mn 2+The binary salt solution reacts with alkali and ammonia.

[0010] S4. After the reaction continues for 10 hours, compressed air is introduced into the reactor and maintained at a stable flow rate for 6-8 hours to oxidize the divalent manganese ions in the reactor to tetravalent manganese ions. At the same time, under the oxidation conditions, the primary particles of the precursor become finer and a loose structure grows on the periphery, thereby increasing the specific surface area of ​​the precursor. The morphology of the entire sphere will also become a loose state.

[0011] S5. After the D50 particle size reaches 2.0-3.5μm during the reaction process, aluminum salt solution is introduced into the reactor, while the flow rates of liquid alkali and ammonia are reduced to lower the pH value and ammonia concentration of the reaction system. When the final D50 particle size reaches 9-13μm, the feeding of salt, alkali, and ammonia is stopped, and the growth reaction ends.

[0012] S6. Place the reacted slurry in an aging tank for 2-3 hours of aging. Then, centrifuge, wash and dry the aging slurry to obtain the precursor powder.

[0013] As a further description of the above technical solution:

[0014] Step S1 contains Ni 2+ Mn 2+ The binary salt solution with Ni X Mn y The general formula of (OH)2 is used as the basis for configuration, where x+y=1, 0.8≤x<1, and 0.01≤y<0.20.

[0015] As a further description of the above technical solution:

[0016] Step S1 contains Ni 2+ Mn 2+ The binary salt solution is prepared by mixing nickel sulfate and manganese sulfate, and the aluminum salt solution is aluminum sulfate.

[0017] As a further description of the above technical solution:

[0018] In step S2, the complexing agent is ammonia water with a content of 20%, the precipitant is sodium hydroxide solution with a content of 30%, the inert gas is nitrogen gas with a flow rate of 3000-7000 mL / h, and the oxygen content is reduced to below 1%.

[0019] As a further description of the above technical solution:

[0020] In step S3, the pH value of the reaction is controlled by adding alkali to be 10.50-12.50, and the ammonia water added in step S3 is controlled to be 0.50-0.90 mol / L.

[0021] As a further description of the above technical solution:

[0022] In step S3, the initial base solution pH is 11.40-11.50, the ammonia concentration is 0.50-0.90 mol / L, the initial stirring rate is 580-600 rpm, the stirring rate during the reaction is 150-600 rpm, the pH during the growth period is 10.65-10.85, and the ammonia concentration is also 0.50-0.90 mol / L.

[0023] As a further description of the above technical solution:

[0024] In step S4, the compressed air flow rate is 300-500 mL / h, maintaining the oxygen content at 1%-2%.

[0025] As a further description of the above technical solution:

[0026] In step S5, the aluminum salt flow rate is 1000-3000 mL / h. After the particle size reaches 3.0 μm, the pH of the reaction system is maintained at 10.45-10.50, and the ammonia concentration is 0.50-0.90 mol / L.

[0027] The present invention has the following beneficial effects:

[0028] Compared with existing technologies, this intermittent preparation method for a high-nickel, aluminum-doped precursor uses a co-precipitation method to prepare nickel-manganese hydroxide, loosens the primary particles by air oxidation to increase their specific surface area, and introduces aluminum salt as a filler after forming a certain degree of sphericity, effectively avoiding surface porosity, and thus forming a high-compact, high-specific-surface-area cathode precursor material. Attached Figure Description

[0029] Figure 1 This is a flowchart of an intermittent preparation method for a high-nickel, aluminum-doped precursor proposed in this invention. Detailed Implementation

[0030] Example 1:

[0031] Reference Figure 1 The present invention provides a method for intermittent preparation of a high-nickel, aluminum-doped precursor, comprising the following steps:

[0032] S1. Choose one of nickel sulfate, nickel nitrate, or nickel chloride to prepare a nickel salt solution. The nickel ions in the nickel salt solution are Ni. 2+ Choose one of manganese sulfate, manganese nitrate, or manganese chloride to prepare a manganese salt solution. The manganese ions in the manganese salt solution are Mn. 2+ The nickel salt solution and manganese salt solution were mixed according to the Ni X Mny Based on the general formula of (OH)2, it is configured to contain Ni. 2+ Mn 2+ A binary salt solution is prepared, wherein x+y=1, 0.8≤x<1, 0.01≤y<0.20, and an aluminum salt solution of 0.1-2mol / L is prepared using aluminum sulfate. Specifically, a certain mass of nickel sulfate and manganese sulfate are added to pure water at 80℃ in a preparation tank and stirred continuously until completely dissolved to prepare a mixed salt solution with a Ni:Mn molar ratio of 0.90:0.10 and a total concentration of 2mol / L. Similarly, an aluminum sulfate solution with a concentration of 0.1-2mol / L, preferably 2mol / L, is prepared in another preparation tank.

[0033] S2. Add pure water to the reactor, and add 20% ammonia water as a complexing agent and 30% sodium hydroxide solution as a precipitant as the base liquid. Specifically, add industrial ammonia water of more than 20% to a 70L reactor to adjust the ammonia concentration to 0.50-0.90mol / L. Similarly, add liquid alkali of more than 32% to the system mixed with dilute ammonia water to adjust the pH to 11.40-11.50. Continuously introduce inert gas such as nitrogen at a rate of 3000-7000mL / h, maintaining a stable flow rate for at least 3 hours to reduce the oxygen content in the reactor to below 1%. During the nitrogen introduction process, control the temperature in the reactor between 40-65℃.

[0034] S3. Turn on the stirring function of the reactor and add Ni into the reactor. 2+ Mn 2+ The reaction involves a binary salt solution, alkali, and ammonia. Specifically, after the base solution is prepared, the stirring speed is adjusted to 580-600 rpm. Once the oxygen content is controlled to below 1%, a certain concentration of ammonia (above 20%) and liquid alkali (above 30%), preferably 32%, are first introduced through a metering pump. Then, a 2 mol / L soluble nickel-manganese mixed salt solution is introduced. During the reaction, the stirring speed is adjusted to 150-600 rpm, the pH during the growth period is 10.65-10.85, and the ammonia concentration is also 0.50-0.90 mol / L. Primary particles are obtained, which are spherical nickel-manganese hydroxide.

[0035] S4. After the reaction continues for 10 hours, compressed air is introduced into the reactor at a flow rate of 300 mL / h to maintain the oxygen content in the reactor at 1%-2%, preferably 2%. The flow rate is maintained at a stable flow rate for 6-8 hours to oxidize divalent manganese ions in the reactor to tetravalent manganese ions (the oxygen content is controlled to be below 2%, and this low oxygen atmosphere is insufficient to oxidize manganese ions to the +6 valence state, which can also ensure the stability of the material structure). At the same time, under the oxidation conditions, the primary particles of the precursor become finer, and a loose structure grows on the periphery, thereby increasing the specific surface area of ​​the precursor. The morphology of the entire sphere also becomes a loose state, and the primary particles are loosened by air oxidation to increase their specific surface area.

[0036] S5. After the D50 particle size reaches 2.0-3.5μm during the reaction process, preferably 3μm, aluminum salt solution is introduced into the reactor at a flow rate of 1000-3000mL / h, while simultaneously reducing the flow rates of liquid alkali and ammonia to lower the pH and ammonia concentration of the reaction system. The introduction of aluminum salt can fill the loose state on the surface of the primary particles, thereby forming a high-compact, high-specific-surface-area positive electrode precursor material. The pH is adjusted to 10.45-10.50 and the ammonia concentration is adjusted to 0.50-0.90mol / L. When the final D50 particle size reaches 9-13μm, the addition of salt, alkali, and ammonia is stopped, and the growth reaction is terminated. If the pH and stirring rate are not properly controlled after 9μm, nucleation and cracking may occur in the precursor morphology. Setting the growth reaction to end at 9μm can avoid the phenomena of nucleation and cracking.

[0037] S6. Place the reacted slurry in an aging tank for 2-3 hours of aging. After aging, centrifuge, wash, dry, and sieve to remove iron to obtain a high-nickel, aluminum-doped precursor powder.

[0038] Example 2:

[0039] Reference Figure 1 The present invention provides a method for intermittent preparation of a high-nickel, aluminum-doped precursor, comprising the following steps:

[0040] S1. Add a certain mass of nickel sulfate and manganese sulfate to pure water at 80°C and stir continuously until completely dissolved to prepare a mixed salt solution with a Ni:Mn molar ratio of 0.90:0.10 and a total concentration of 2 mol / L. Similarly, prepare a 2 mol / L aluminum sulfate solution in another preparation tank.

[0041] S2. Add 20% industrial ammonia water to a 70L water reactor to prepare an ammonia concentration of 0.90mol / L. Similarly, add 32% liquid alkali to the system mixed with dilute ammonia water to make its pH 11.40.

[0042] S3. After the base liquid is prepared, adjust the stirring speed to 580 rpm. After the oxygen content is controlled to below 1%, first introduce a certain flow rate of 20% ammonia water and 32% liquid alkali through the metering pump, and then introduce 2 mol / L of soluble nickel and manganese mixed salt.

[0043] S4. After reacting for 10 hours, introduce air at a rate of 300 mL / h to maintain an oxygen content of 2%. After 12 hours, adjust the pH to 10.65 and maintain the ammonia concentration at 0.90. Once the D50 particle size reaches 3 μm, adjust the pH to 10.45 and the ammonia concentration to 0.60.

[0044] S5. After the D50 particle size reaches 3.5μm, aluminum sulfate solution is introduced into the reaction system through a metering pump. After the particle size reaches 9μm, the introduction of mixed salt, alkali and ammonia is stopped.

[0045] S6. Place the material from step S5 into an aging kettle for aging for 2 hours, then wash, dry, and sieve to remove iron to obtain a high-nickel, aluminum-doped precursor powder.

[0046] Example 3:

[0047] Reference Figure 1 The present invention provides a method for intermittent preparation of a high-nickel, aluminum-doped precursor, comprising the following steps:

[0048] S1. Add a certain mass of nickel sulfate and manganese sulfate to pure water at 80°C and stir continuously until completely dissolved to prepare a mixed salt solution with a Ni:Mn molar ratio of 0.90:0.10 and a total concentration of 2 mol / L. Similarly, prepare a 2 mol / L aluminum sulfate solution in another preparation tank.

[0049] S2. Add 20% industrial ammonia water to a 70L water reactor to prepare an ammonia concentration of 0.90mol / L. Similarly, add 32% liquid alkali to the system mixed with dilute ammonia water to make its pH 11.45.

[0050] S3. After the base liquid is prepared, adjust the stirring speed to 580 rpm. After the oxygen content is controlled to below 1%, first introduce a certain flow rate of 20% ammonia water and 32% liquid alkali through the metering pump, and then introduce 2 mol / L of soluble nickel and manganese mixed salt.

[0051] S4. After reacting for 10 hours, introduce air at a rate of 300 mL / h to maintain an oxygen content of 2%. After 12 hours, adjust the pH to 10.75 and maintain the ammonia concentration at 0.90. Once the D50 particle size reaches 3 μm, adjust the pH to 10.45 and the ammonia concentration to 0.60.

[0052] S5. After the D50 particle size reaches 3.5μm, aluminum sulfate solution is introduced into the reaction system through a metering pump. After the particle size reaches 13μm, the introduction of mixed salt, alkali and ammonia is stopped.

[0053] S6. Place the material from step S5 into an aging kettle for aging for 2 hours, then wash, dry, and sieve to remove iron to obtain a high-nickel, aluminum-doped precursor powder.

[0054] Working principle: A soluble binary salt solution and a certain concentration of aluminum salt are prepared, and nickel manganese hydroxide is prepared by co-precipitation. The primary particles are loosened by air oxidation to increase their specific surface area. After a certain degree of sphericity is formed, aluminum salt is introduced as a filler to effectively avoid surface porosity, thereby forming a high-compact, high-specific-surface-area positive electrode precursor material. Furthermore, the products prepared in each reaction step are clearly defined, and the precursor can be prepared in a sequential and intermittent manner.

[0055] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for intermittent preparation of a high-nickel, aluminum-doped precursor, characterized in that: Includes the following steps: S1, Configuration containing Ni 2+ Mn 2+ Prepare a binary salt solution and a 0.1-2 mol / L aluminum salt solution; S2. Add pure water, complexing agent, and precipitant to the reactor as the base liquid, and continuously introduce inert gas to maintain a stable flow rate for 3 hours to reduce the oxygen content in the reactor. During the process, control the temperature in the reactor between 40-65℃. S3. Turn on the stirring function of the reactor and add Ni into the reactor. 2+ Mn 2+ The binary salt solution reacts with alkali and ammonia. S4. After the reaction continues for 10 hours, compressed air is introduced into the reactor and maintained at a stable flow rate for 6-8 hours to oxidize the divalent manganese ions in the reactor to tetravalent manganese ions. At the same time, under the oxidation conditions, the primary particles of the precursor become finer and a loose structure grows on the periphery, thereby increasing the specific surface area of ​​the precursor. The morphology of the entire sphere will also become a loose state. S5. After the D50 particle size reaches 2.0-3.5μm during the reaction process, aluminum salt solution is introduced into the reactor, while the flow rates of liquid alkali and ammonia are reduced to lower the pH value and ammonia concentration of the reaction system. When the final D50 particle size reaches 9-13μm, the feeding of salt, alkali, and ammonia is stopped, and the growth reaction ends. S6. Place the reacted slurry in an aging tank for 2-3 hours of aging. Then, centrifuge, wash and dry the aging slurry to obtain the precursor powder.

2. The method for intermittent preparation of a high-nickel, aluminum-doped precursor according to claim 1, characterized in that: Step S1 contains Ni 2+ Mn 2+ The binary salt solution with Ni X Mn y The general formula of (OH)2 is used as the basis for configuration, where x+y=1, 0.8≤x<1, and 0.01≤y<0.

20.

3. The method for intermittent preparation of a high-nickel, aluminum-doped precursor according to claim 1, characterized in that: Step S1 contains Ni 2+ Mn 2+ The binary salt solution is prepared by mixing nickel sulfate and manganese sulfate, and the aluminum salt solution is aluminum sulfate.

4. The method for intermittent preparation of a high-nickel, aluminum-doped precursor according to claim 1, characterized in that: In step S2, the complexing agent is ammonia water with a content of 20%, the precipitant is sodium hydroxide solution with a content of 30%, the inert gas is nitrogen gas with a flow rate of 3000-7000 mL / h, and the oxygen content is reduced to below 1%.

5. The method for intermittent preparation of a high-nickel, aluminum-doped precursor according to claim 1, characterized in that: In step S3, the pH value of the reaction is controlled by adding alkali to be 10.50-12.50, and the ammonia water added in step S3 is controlled to be 0.50-0.90 mol / L.

6. The method for intermittent preparation of a high-nickel, aluminum-doped precursor according to claim 5, characterized in that: In step S3, the initial base solution pH is 11.40-11.50, the ammonia concentration is 0.50-0.90 mol / L, the initial stirring rate is 580-600 rpm, the stirring rate during the reaction is 150-600 rpm, the pH during the growth period is 10.65-10.85, and the ammonia concentration is also 0.50-0.90 mol / L.

7. The method for intermittent preparation of a high-nickel, aluminum-doped precursor according to claim 1, characterized in that: In step S4, the compressed air flow rate is 300-500 mL / h, maintaining the oxygen content at 1%-2%.

8. The method for intermittent preparation of a high-nickel, aluminum-doped precursor according to claim 1, characterized in that: In step S5, the aluminum salt flow rate is 1000-3000 mL / h. After the particle size reaches 3.0 μm, the pH of the reaction system is maintained at 10.45-10.50, and the ammonia concentration is 0.50-0.90 mol / L.

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