Low-sodium-sulfur basic carbonate small-particle precursor as well as preparation method and application thereof

Abstract

The invention provides a low-sodium-sulfur basic carbonate small-particle precursor and a preparation method and application thereof.The preparation method comprises the following steps that a nickel-cobalt-manganese mixed source solution and a precipitator solution are introduced into a base solution for a co-precipitation reaction, the pH of a system is gradually reduced to the target pH in the co-precipitation reaction process, and the low-sodium-sulfur basic carbonate small-particle precursor is obtained under the target pH; reacting until the particle size D50 of a product reaches a target particle size D50, ending the reaction, and then aging, washing and drying to obtain the low-sodium-sulfur basic carbonate small-particle precursor; the precipitant solution comprises carbonate and metal hydroxide, and a complexing agent is not added during the co-precipitation reaction. According to the preparation method disclosed by the invention, the carbonate and the hydroxide are used as precipitants to synthesize the small-particle basic carbonate with low sodium-sulfur content, so that the influence of sodium-sulfur impurities in the precursor on the electrochemical performance of the cathode material obtained in the later period is avoided.

Description

Technical Field

[0001] This invention belongs to the field of battery technology and relates to a low-sodium-sulfur basic carbonate small particle precursor, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries have established irreplaceable advantages in consumer electronics, electric vehicles, and energy storage due to their high energy density, long cycle life, and recyclability. Ternary cathode materials, with their high energy density and good cycle performance, have become core materials for lithium-ion batteries in high-end power and energy storage scenarios. However, the high cost of ternary cathode materials limits their application, making cost control a major direction for the development and optimization of ternary cathode materials. Current technologies mostly use co-precipitation to obtain ternary precursors, which are then sintered to obtain the ternary cathode material. Ternary precursors synthesized by co-precipitation are mainly divided into hydroxide precursors and carbonate precursors. Compared to hydroxide precursors, carbonate precursors require less monitoring and control during the reaction process, can be carried out in air without the need for continuous aeration to maintain an oxygen-free environment, and do not produce nitrogen-containing wastewater, making them environmentally friendly and effectively controlling costs.

[0003] For example, CN117566813A discloses a method for preparing a carbonate precursor, a single-crystal ternary cathode material, and its preparation method and application. This method prepares a carbonate precursor and sintersects it into a single-crystal cathode material, testing its electrochemical performance. However, this method is a small-scale laboratory experiment with a short reaction time, resulting in low industrial production efficiency. Furthermore, the obtained precursor is not well-formed, has poor morphology, and its uniformity needs improvement. Another example is CN113023789A, which prepares a large specific surface area olive-shaped carbonate ternary precursor. However, due to the excessively low initial pH, the supernatant turns green, indicating severe nickel runoff. This causes the synthesized precursor to deviate from the desired molar ratio, and significantly increases the industrial synthesis cost, contradicting the goal of cost reduction and efficiency improvement.

[0004] Furthermore, the co-precipitation method for preparing carbonate precursors also has the following drawbacks: (1) During the preparation of carbonates, sodium and sulfur ions in the solution will be adsorbed and coated in the precursor grains as the reaction proceeds. The sodium and sulfur impurities in the finished product will occupy some lithium ion sites during the subsequent sintering process, which will lead to a decrease in the capacity and cycle performance of the material. This will not only affect the electrochemical performance of the material, but also lead to a decrease in the safety performance of the battery. (2) Although a precursor with a certain morphology can be obtained in the process of synthesizing carbonates without adding a complexing agent, which can reduce the production cost of the precursor to a certain extent, the starting particle size of the carbonate precursor particles is large during the nucleation stage, and the preparation of small-particle carbonate precursors is another major problem.

[0005] Based on the above research, there is a need to provide a method for preparing a low-sodium-sulfur basic carbonate small particle precursor. The preparation method can synthesize small particle products while reducing costs and increasing efficiency, and also reduces the sodium-sulfur impurity content in the precursor, preventing the sodium-sulfur impurities in the precursor from affecting the electrochemical performance of the cathode material obtained later. Summary of the Invention

[0006] The purpose of this invention is to provide a low-sodium-sulfur basic carbonate small particle precursor, its preparation method, and its application. The preparation method uses carbonate and hydroxide as precipitants to synthesize low-sodium-sulfur small particle basic carbonate, thus avoiding the influence of sodium and sulfur impurities in the precursor on the electrochemical performance of the obtained cathode material.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a low-sodium-sulfur basic carbonate small particle precursor, the preparation method comprising the following steps:

[0009] A nickel-cobalt-manganese mixed source solution and a precipitant solution were introduced into the base liquid to carry out a co-precipitation reaction. During the co-precipitation reaction, the pH of the system was gradually reduced to the target pH. At the target pH, the reaction was stopped when the product particle size D50 reached the target particle size D50. Then, the product was aged, washed and dried to obtain the low sodium sulfur basic carbonate small particle precursor.

[0010] The precipitant solution includes a composite precipitant, which comprises a carbonate and a metal hydroxide.

[0011] The base liquid includes pure water and the composite precipitant;

[0012] No complexing agent was added during the coprecipitation reaction.

[0013] Since carbonate precipitation yields different products under different pH conditions, both carbonates and hydroxides have corresponding optimal pH conditions for precipitation. As pH increases, carbonate precipitation is slower, and the solution mainly exists as hydroxide precipitation. As pH gradually decreases, the precipitate in the solution transforms into carbonate. Based on the precipitation equilibrium constants of various metal ions, it was found that the precipitation rate of Mn ions with carbonate is too fast, while the precipitation rate of its hydroxide is relatively slow. Therefore, this invention simultaneously introduces a precipitant solution containing carbonate and metal hydroxide during the reaction process to generate a basic carbonate, controlling its growth rate and preventing problems such as reduced production capacity and morphological uniformity caused by excessively rapid growth.

[0014] In other words, this invention uses carbonates and metal hydroxides as composite precipitants, and the bottom solution includes pure water and the composite precipitant. As the feed solution is introduced, the pH of the system gradually decreases. Initially, at a high pH, ​​hydroxide precipitation is the main process, with a small number of hydroxide nuclei forming in the early stage. As the pH of the system decreases, the carbonate precipitation rate increases. Therefore, using carbonates and metal hydroxides as composite precipitants can control the product growth rate and obtain products with small particle sizes. After washing, basic carbonates with low sodium and sulfur content can be obtained. The synthesis is carried out without the use of complexing agents, and no nitrogen-containing wastewater is produced, making it green and environmentally friendly. This reduces costs to a certain extent. Furthermore, the reaction process does not require precise pH control, greatly simplifying the process. The synthesis can be carried out in an air atmosphere, which, compared to traditional synthesis methods, does not require continuous nitrogen gas supply, further simplifying the process.

[0015] The small-particle precursor of this invention is mainly used for preparing single-crystal ternary cathode materials, suitable for fields with high requirements for battery energy density, rate performance, and cycle life, such as high-end new energy vehicles and energy storage batteries. Compared with large-particle precursors, small-particle precursors have a relatively large specific surface area and a large contact area with the electrolyte, which is beneficial for lithium-ion insertion and extraction during battery charging and discharging, thus improving the battery's rate performance. Furthermore, they have higher solid-state reactivity, making it easier to form a single-crystal structure, and requiring shorter sintering temperatures and times. Under high-voltage charge and discharge conditions, the small-particle single-crystal precursor has fewer structural defects, effectively reducing side reactions with the electrolyte and resulting in better cycle performance.

[0016] Preferably, in the composite precipitant solution, the molar ratio of carbonate to metal hydroxide is 1:(0.5-2.5), for example, it can be 1:0.5, 1:1, 1:1.5, 1:2 or 1:2.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] In the composite precipitant solution of this invention, the molar ratio of carbonate to metal hydroxide affects the particle growth rate. If there is too much carbonate and too little metal hydroxide, large-diameter nucleus particles are directly obtained, resulting in a large initial particle size of the precursor, which cannot be used for subsequent reactions to synthesize small-particle precursors. However, if there is too little carbonate and too much metal hydroxide, the precursor grows slowly as the reaction proceeds, and the time required to reach the target particle size is long.

[0018] Preferably, the carbonate includes sodium carbonate.

[0019] Preferably, the metal hydroxide includes sodium hydroxide.

[0020] Preferably, the pH of the base solution is 11.5-12, for example, it can be 11.5, 11.6, 11.7, 11.8, 11.9 or 12, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, during the coprecipitation reaction, the pH of the system is gradually reduced from 11.5-12 to the target pH, that is, from the pH of the base liquid to the target pH.

[0022] This invention starts with the pH of the base solution and gradually decreases the pH of the system as the feed is introduced. Therefore, the pH of the base solution affects the initial pH of the system, the early particle growth rate, and thus the particle size of the crystal nuclei. If the pH of the base solution is too high, the large number of small crystal nuclei synthesized are prone to agglomerate into large particles, and the high pH is maintained for too long, which will lead to a prolonged reaction time. If the pH of the base solution is too low, the transition metal ions will not precipitate completely, and the element content of the precursor synthesized in the subsequent synthesis will deviate from the target synthesis value. At the same time, it will increase the cost and bring economic losses in industry.

[0023] Preferably, the target pH is 7.0-9.0, for example, it can be 7, 7.5, 8, 8.5 or 9, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, during the coprecipitation reaction process, the particle size D50 of the resulting crystal nuclei is 2μm-3μm, for example, it can be 2μm, 2.2μm, 2.4μm, 2.6μm, 2.8μm or 3μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] Preferably, the target particle size D50 is 3.5μm-5.0μm, for example, it can be 3.5μm, 4μm, 4.5μm or 5μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] It is understood that the target particle size D50 described in this invention is the same as the particle size D50 of the obtained product.

[0027] Preferably, the temperature of the coprecipitation reaction is 40℃-80℃, for example, it can be 40℃, 50℃, 60℃, 70℃ or 80℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Since the solubility of sodium carbonate is inversely proportional to temperature, higher reaction temperatures result in higher supersaturation, more nucleation, and a greater number of nuclei, thus controlling the initial particle size within a smaller range. This is beneficial for further reaction and synthesis of smaller particle precursors. Therefore, a higher temperature can be maintained in the early stages or throughout the reaction. After the reaction is complete, repeated hot water washing can remove the Na adsorbed in the crystal lattice. + This reduces the Na impurity content in the finished precursor product.

[0029] Preferably, the coprecipitation reaction time is 8h-70h, for example, it can be 8h, 15h, 20h, 30h, 40h, 50h, 60h or 70h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the stirring rate of the coprecipitation reaction is 700 rpm to 900 rpm, for example, 700 rpm, 750 rpm, 800 rpm, 850 rpm or 900 rpm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, in the nickel-cobalt-manganese mixed source solution, the molar ratio of nickel ions, cobalt ions, and manganese ions is x:y:(1-xy), where 0.7≤x≤0.9, for example, it can be 0.7, 0.75, 0.8, 0.85, or 0.9, and 0≤y≤0.3, for example, it can be 0, 0.05, 0.1, 0.15, 0.2, 0.25, or 0.3, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, the concentration of the nickel-cobalt-manganese mixed source solution is 80-120 g / L, for example, it can be 80 g / L, 90 g / L, 100 g / L, 110 g / L or 120 g / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, in the low-sodium-sulfur basic carbonate particle precursor, the sodium content is below 700 ppm, for example, it can be 700 ppm, 650 ppm, 600 ppm, 550 ppm, 500 ppm, 450 ppm, 400 ppm or 350 ppm, and the sulfur content is below 800 ppm, for example, it can be 800 ppm, 750 ppm, 700 ppm, 650 ppm, 600 ppm, 550 ppm, 500 ppm, 450 ppm or 400 ppm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0034] In a second aspect, the present invention provides a low-sodium-sulfur basic carbonate particle precursor, which is prepared by the preparation method described in the first aspect.

[0035] Thirdly, the present invention provides an application of the low-sodium-sulfur basic carbonate particle precursor as described in the second aspect, the application including its use in the preparation of cathode materials for batteries.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] This invention employs carbonates and metal hydroxides as composite precipitants, with the underlying solution comprising pure water and the composite precipitant. As the feed solution is introduced, the pH of the system gradually decreases. Initially, at a high pH, ​​hydroxide precipitation is dominant, with a small number of hydroxide nuclei forming in the early stages. As the pH decreases, the carbonate precipitation rate accelerates. Therefore, using carbonates and metal hydroxides as composite precipitants allows for control of product growth rate, resulting in small-particle-size products. After washing, low-sodium-sulfur basic carbonates are obtained. Synthesis occurs without the use of complexing agents, producing no nitrogen-containing wastewater, making it environmentally friendly and reducing costs to some extent. Furthermore, the reaction process does not require precise pH control, greatly simplifying the process. Synthesis can be performed in an air atmosphere, eliminating the need for continuous nitrogen supply compared to traditional synthesis methods, further simplifying the process. Attached Figure Description

[0038] Figure 1 This is a SEM image of the precursor obtained in Example 1 of the present invention.

[0039] Figure 2 This is a SEM image of the precursor obtained in Embodiment 2 of the present invention.

[0040] Figure 3 This is a SEM image of the precursor obtained in Example 3 of the present invention.

[0041] Figure 4 This is a SEM image of the precursor obtained in Comparative Example 3 of the present invention. Detailed Implementation

[0042] 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.

[0043] Example 1

[0044] This embodiment provides a method for preparing a low-sodium, low-sulfur basic carbonate small particle precursor, the preparation method comprising the following steps:

[0045] (1) Prepare a nickel-cobalt-manganese mixed source solution with a concentration of 100 g / L and a molar ratio of Ni ions, Co ions and Mn ions of 0.8:0.1:0.1, and prepare a mixed precipitant solution including a composite precipitant, wherein the composite precipitant includes Na2CO3 and NaOH with a molar ratio of 1:0.91;

[0046] Add 8 kg of pure water and 8 g of composite precipitant to a 20 L reactor as a base solution. The pH of the base solution is 11.8. Stir and heat to stabilize at 58 °C. The stirring rate is 800 rpm.

[0047] (2) The nickel-cobalt-manganese mixed source solution and the mixed precipitant solution were fed into the bottom liquid at the same time. The pH of the system gradually decreased from 11.8 to 7.8. When a certain liquid level was reached during the reaction, it was discharged from the overflow port. The particle size D50 of the obtained crystal nuclei was 2.67 μm, and the particle size D50 of the product after 44 h of feeding was 3.30 μm.

[0048] (3) After the reaction is completed, the material is allowed to stand until it separates into layers. The upper clear liquid is removed, water is added to a certain level, and the material in the reactor is aged for 12 hours at 60°C and 80 rpm. After washing with hot water 6 times, it is dried at 150°C for 24 hours to obtain the low sodium sulfur basic carbonate small particle precursor.

[0049] The SEM image of the precursor obtained in this embodiment is as follows: Figure 1 As shown.

[0050] Example 2

[0051] This embodiment provides a method for preparing a low-sodium, low-sulfur basic carbonate small particle precursor, the preparation method comprising the following steps:

[0052] (1) Prepare a nickel-cobalt-manganese mixed source solution with a concentration of 80 g / L and a molar ratio of Ni ions, Co ions and Mn ions of 0.7:0.15:0.15, and prepare a mixed precipitant solution including a composite precipitant, wherein the composite precipitant includes Na2CO3 and NaOH with a molar ratio of 1:0.5;

[0053] Pure water and a composite precipitant were added to a 20L reactor as a base solution with a pH of 12. The mixture was stirred and heated to a stable temperature of 75°C at a stirring speed of 700 rpm.

[0054] (2) The nickel-cobalt-manganese mixed source solution and the mixed precipitant solution were fed into the bottom liquid at the same time. The pH of the system was gradually reduced from 12 to 9.0. When a certain liquid level was reached during the reaction, the solution was discharged from the overflow port. The particle size D50 of the obtained crystal nuclei was 2.59 μm, and the particle size D50 of the product after 60 h of feeding was 4.08 μm.

[0055] (3) After the reaction is completed, the material is allowed to stand until it separates into layers. The upper clear liquid is removed, water is added to a certain level, and the material in the reactor is aged for 12 hours at 60°C and 80 rpm. After washing with hot water 6 times, it is dried at 150°C for 24 hours to obtain the low sodium sulfur basic carbonate small particle precursor.

[0056] The SEM image of the precursor obtained in this embodiment is as follows: Figure 2 As shown.

[0057] Example 3

[0058] This embodiment provides a method for preparing a low-sodium, low-sulfur basic carbonate small particle precursor, the preparation method comprising the following steps:

[0059] (1) Prepare a nickel-cobalt-manganese mixed source solution with a concentration of 120 g / L and a molar ratio of Ni ions, Co ions and Mn ions of 0.8:0.1:0.1, and prepare a mixed precipitant solution including a composite precipitant, wherein the composite precipitant includes Na2CO3 and NaOH with a molar ratio of 1:2.5;

[0060] Pure water and a composite precipitant were added to a 20L reactor as a base solution with a pH of 11.5. The mixture was stirred and heated to a stable temperature of 65°C at a stirring rate of 900 rpm.

[0061] (2) The nickel-cobalt-manganese mixed source solution and the mixed precipitant solution were fed into the bottom liquid at the same time. The pH of the system gradually decreased from 11.5 to 7.0. When a certain liquid level was reached during the reaction, it was discharged from the overflow port. The particle size D50 of the obtained crystal nuclei was 3.04 μm, and the particle size D50 of the product after 10 h of feeding was 4.12 μm.

[0062] (3) After the reaction is completed, the material is allowed to stand until it separates into layers. The upper clear liquid is removed, water is added to a certain level, and the material in the reactor is aged for 12 hours at 60°C and 80 rpm. After washing with hot water 6 times, it is dried at 150°C for 24 hours to obtain the low sodium sulfur basic carbonate small particle precursor.

[0063] The SEM image of the precursor obtained in this embodiment is as follows: Figure 3 As shown.

[0064] Example 4

[0065] This embodiment provides a method for preparing a low-sodium-sulfur basic carbonate small particle precursor. Except for step (1), in which the composite precipitant includes Na2CO3 and NaOH in a molar ratio of 1:3.69 to adapt the particle size D50 of the obtained crystal nuclei and the particle size D50 of the product, the preparation method is the same as in Example 1.

[0066] Example 5

[0067] This embodiment provides a method for preparing a low-sodium-sulfur basic carbonate small particle precursor. Except for step (1), in which the composite precipitant includes Na2CO3 and NaOH in a molar ratio of 1:0.26 to adapt the particle size D50 of the obtained crystal nuclei and the particle size D50 of the product, the preparation method is the same as in Example 1.

[0068] Example 6

[0069] This embodiment provides a method for preparing a low-sodium-sulfur basic carbonate small particle precursor. Except for step (1), where the pH of the base solution is 10.5 and the pH of the system is gradually reduced from 10.5 to 7.8 to adapt the changes in the particle size D50 of the obtained crystal nuclei and the particle size D50 of the product, the preparation method is the same as in Example 1.

[0070] Example 7

[0071] This embodiment provides a method for preparing a low-sodium-sulfur basic carbonate small particle precursor. Except for step (1), where the pH of the base solution is 12.5 and the pH of the system is gradually reduced from 12.5 to 7.8 to adapt the changes in the particle size D50 of the obtained crystal nuclei and the particle size D50 of the product, the preparation method is the same as in Example 1.

[0072] Comparative Example 1

[0073] This comparative example provides a method for preparing a precursor. Except for step (1), in which the base liquid contains only 8 kg of pure water to adapt the particle size D50 of the obtained crystal nuclei and the particle size D50 of the product to change, the preparation method is the same as in Example 1.

[0074] Comparative Example 2

[0075] This comparative example provides a method for preparing a precursor. Except for step (1), in which the base liquid includes 8 kg of pure water and 8 g of Na2CO3 to adapt the particle size D50 of the obtained crystal nuclei and the particle size D50 of the product, the preparation method is the same as in Example 1.

[0076] Comparative Example 3

[0077] This comparative example provides a method for preparing a precursor. Except for step (1), in which the base solution includes 8 kg of pure water and 8 g of NaOH to adapt the particle size D50 of the obtained crystal nuclei and the particle size D50 of the product, the preparation method is the same as in Example 1.

[0078] The SEM image of the precursor obtained in this comparative example is shown below. Figure 4 As shown.

[0079] Comparative Example 4

[0080] This comparative example provides a method for preparing a precursor. Except for step (1), in which the mixed precipitant solution does not contain NaOH and only uses sodium carbonate solution as the precipitant solution to adapt the particle size D50 of the obtained crystal nuclei and the particle size D50 of the product to change, the preparation method is the same as in Example 1.

[0081] In the preparation methods described in the above embodiments and comparative examples, the crystal nucleus particle size D50, the product particle size D50, and the sodium and sulfur content in the precursor are shown in Table 1:

[0082] Table 1

[0083]

[0084] As can be seen from Table 1 above:

[0085] As shown in Example 1 and Comparative Example 1, when the base solution is pure water, the crystal nucleus particle size is relatively large, and the particle size further increases during subsequent reactions, which does not meet the requirements for preparing small particle precursors. As shown in Example 1 and Comparative Example 2, when the base solution includes pure water and sodium carbonate but does not contain sodium hydroxide, adding excessive sodium carbonate accelerates particle growth, resulting in a larger crystal nucleus particle size and a larger final product particle size (D50), thus failing to obtain small particle products. As shown in Example 1 and Comparative Example 3, when the base solution includes pure water and sodium hydroxide but does not contain sodium carbonate, the particle sizes D50 and D10 increase slowly as the reaction proceeds, but after a certain reaction time, D10 gradually decreases, and D50 increases slowly or even shows a decreasing trend, resulting in a small particle product. The precursor has high levels of Na and S impurities. As shown in Example 1 and Comparative Example 4, using only sodium carbonate solution as the precipitant results in excessively large crystal nuclei, making it impossible to obtain small-particle precursors. As shown in Examples 1 and 4, excessive sodium hydroxide in the precipitant solution leads to smaller crystal nuclei (D50), but the precursor growth is slow as the reaction proceeds. As shown in Examples 1 and 5, insufficient sodium hydroxide in the precipitant solution results in larger crystal nuclei (D50), leading to larger precursor particle sizes. As shown in Examples 1 and Examples 6-7, the pH of the base solution affects the initial pH of the system, influencing the early particle growth rate, which in turn affects the crystal nuclei size and product particle size.

[0086] 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 producing low-sodium, sulfur subcarbonate small-particle precursors, characterized by, The preparation method comprises the following steps: The nickel-cobalt-manganese mixed source solution and the precipitant solution are introduced into the base solution to perform a co-precipitation reaction, during which the pH of the system gradually decreases to a target pH, and the reaction is ended when the product particle size D50 reaches a target particle size D50 at the target pH, and then aging, washing and drying are performed to obtain the low-sodium alkali carbonate small particle precursor of sulfur; The precipitant solution comprises a composite precipitant, and the composite precipitant comprises a carbonate and a metal hydroxide; The base solution comprises pure water and the composite precipitant; During the co-precipitation reaction, no complexing agent is added.

2. The production method according to claim 1, characterized by, In the composite precipitant solution, the molar ratio of the carbonate to the metal hydroxide is 1:(0.5-2.5); Preferably, the carbonate comprises sodium carbonate. Preferably, the metal hydroxide comprises sodium hydroxide.

3. The production method according to claim 1 or 2, characterized by, The pH of the base solution is 11.5-12.

4. The production method according to claim 1 or 2, characterized by, During the co-precipitation reaction, the pH of the system gradually decreases from 11.5-12 to a target pH. Preferably, the target pH is 7.0-9.

0.

5. The production method according to claim 1 or 2, characterized by, During the co-precipitation reaction, the particle size D50 of the obtained crystal nucleus is 2-3 μm. Preferably, the target particle size D50 is 3.5-5.0 μm.

6. The production method according to claim 1 or 2, characterized by, The temperature of the co-precipitation reaction is 40-80 ℃. Preferably, the time of the co-precipitation reaction is 8-70 h. Preferably, the stirring rate of the co-precipitation reaction is 700-900 rpm.

7. The production method according to claim 1 or 2, characterized by, In the nickel-cobalt-manganese mixed source solution, the molar ratio of nickel ions, cobalt ions and manganese ions is x:y:(1-x-y), wherein 0.7≤x≤0.9 and 0≤y≤0.

3. Preferably, the concentration of the nickel-cobalt-manganese mixed source solution is 80-120 g / L.

8. The production method according to claim 1 or 2, characterized by, In the low-sodium alkali carbonate small particle precursor of sulfur, the content of sodium is below 700 ppm, and the content of sulfur is below 800 ppm.

9. A low-sodium, sulfur subcarbonate small particle precursor, characterized in that, The low-sodium alkali carbonate small particle precursor of sulfur is prepared by the preparation method according to any one of claims 1-8.

10. Use of low-sodium sulfur basic carbonate small particles precursors according to claim 9, characterized in that, The application comprises a positive electrode material for preparing a battery.

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