A lithium-rich manganese-based nickel-manganese carbonate precursor, a preparation method and application thereof
By controlling the pH value during the nucleation and growth stages and using carbonates as precipitants, the problems of sphericity and particle uniformity of lithium-rich manganese-based nickel-manganese precursors were solved, enabling efficient and low-cost industrial production and improving battery performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GEM CO LTD
- Filing Date
- 2024-03-27
- Publication Date
- 2026-07-24
AI Technical Summary
Existing methods for preparing lithium-rich manganese-based nickel-manganese precursors suffer from problems such as poor sphericity, uneven particle size, low tap density, and small specific surface area. Furthermore, existing methods are complex and costly, which is not conducive to industrial production.
By using carbonate as a precipitant and adjusting the pH value during the nucleation and growth stages, a nickel-manganese co-precipitation reaction is achieved, resulting in a lithium-rich manganese-based nickel-manganese carbonate precursor with high sphericity and uniform particle distribution, thus avoiding the use of complexing agents and inert gas protection.
The prepared precursor has high sphericity and uniform particle distribution, high tap density, large specific surface area, simple operation, reduced production cost, is suitable for industrial production, and improves the discharge capacity and capacity retention of the battery.
Smart Images
Figure CN118239532B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery materials technology, and relates to a lithium-rich manganese-based nickel-manganese carbonate precursor, its preparation method, and its application. Background Technology
[0002] In recent years, lithium-rich manganese-based cathode materials have exhibited high specific capacity (≥250 mAh g⁻¹) at relatively high charging voltages. -1 Cobalt is considered one of the ideal choices for future power sources with long driving ranges. Because cobalt is a scarce resource, expensive, and prone to environmental pollution, research on lithium-rich manganese-based cathode materials is gradually moving towards cobalt-free alternatives. The development of nickel-manganese binary precursors is crucial for developing high-performance cobalt-free lithium-rich manganese-based cathode materials.
[0003] Co-precipitation is currently the mainstream preparation method for lithium-rich manganese-based nickel-manganese precursors. It involves first preparing the precursor through co-precipitation, then mixing and sintering the precursor with lithium salt to finally obtain the corresponding lithium-rich manganese-based cathode material.
[0004] Coprecipitation methods are generally divided into two types: hydroxide systems and carbonate systems. Lithium-rich manganese-based precursors prepared by the hydroxide system coprecipitation method suffer from problems such as poor sphericity, large compositional fluctuations, and low tap density. The particles exhibit irregular morphology and poor sphericity, and require inert gas protection throughout the process, resulting in low TD and BET values. In contrast, precursors prepared by the carbonate system coprecipitation method have more regular morphology, milder reaction conditions, and require no gas introduction throughout the process, thus reducing production costs.
[0005] CN111498908A successfully prepared a near-spherical manganese-rich carbonate ternary precursor by adding a composite complexing agent and a crystal nucleation control agent. This method can obtain near-spherical precursors with high tap density. However, the sphericity and dispersibility of the precursors obtained by this method are very poor, and the additional crystal nucleation agent increases the growth cost, which is not conducive to large-scale industrial production.
[0006] CN114195204A discloses a method for preparing a high-sphericity manganese-rich carbonate precursor. This method uses ammonia as a complexing agent and employs multiple steps, including "nucleus preparation, nucleus aging, nucleus concentration and dilution, crystal growth, and crystal aging," to improve the poor particle morphology and porous surface of traditional manganese-rich precursors. Although the sphericity is improved, this method requires replacing the supernatant and mother liquor and performing nucleus aging during the reaction process, making the operation complex and generating a large amount of ammonia-containing wastewater, increasing the difficulty of industrial production. Furthermore, the precursor is unevenly distributed, with varying particle sizes and a low specific surface area of only 5-30 m². 2 / g.
[0007] Therefore, there is a need to provide a simple and industrially convenient method for preparing lithium-rich manganese-based nickel-manganese carbonate precursors. The method produces precursor particles with uniform distribution, high sphericity, and high tap density and specific surface area. Summary of the Invention
[0008] The purpose of this invention is to provide a lithium-rich manganese-based nickel-manganese carbonate precursor, its preparation method, and its application. This invention uses carbonate as a precipitant and achieves nickel-manganese co-precipitation reaction by controlling the pH during the nucleation and growth stages. The prepared lithium-rich manganese-based nickel-manganese carbonate precursor has high sphericity and uniform particle distribution.
[0009] To achieve this objective, the present invention adopts the following technical solution:
[0010] In a first aspect, the present invention provides a method for preparing a lithium-rich manganese-based nickel-manganese carbonate precursor, the method comprising the following steps:
[0011] (1) The nickel-manganese mixed salt solution and the carbonate solution were injected into the bottom liquid in a co-current manner, and the nucleation reaction was carried out at the first pH.
[0012] (2) Adjust the pH of the reaction system and carry out the growth reaction at the second pH to obtain the lithium-rich manganese-based nickel-manganese carbonate precursor.
[0013] Wherein, the first pH < the second pH.
[0014] This invention uses carbonates as a precipitant, eliminating the need for complexing agents and inert gas protection. The reaction operation is simple, and the production cost is low. By controlling the pH value during the nucleation and growth stages, the problems of uneven particle distribution, poor sphericity, and low specific surface area in existing lithium-rich manganese precursors can be effectively solved.
[0015] Preferably, the molar ratio of nickel to manganese in the nickel-manganese mixed salt solution in step (1) is Ni:Mn=x:y, x+y=1, x≥0.6.
[0016] Preferably, the mass concentration of the nickel-manganese mixed salt solution is 80-120 g / L, for example: 80 g / L, 90 g / L, 100 g / L, 110 g / L or 120 g / L, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0017] Preferably, the solute in the carbonate solution in step (1) includes any one or a combination of at least two of sodium carbonate, sodium bicarbonate, potassium carbonate, ammonium bicarbonate, or ammonium carbonate. Typical but non-limiting combinations include combinations of sodium carbonate and sodium bicarbonate, combinations of sodium carbonate and potassium carbonate, combinations of sodium bicarbonate and ammonium bicarbonate, etc.
[0018] Preferably, the mass concentration of the carbonate solution is 50 to 500 g / L, for example: 50 g / L, 100 g / L, 200 g / L, 300 g / L or 500 g / L, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0019] Preferably, the base liquid in step (1) comprises water and carbonate.
[0020] Preferably, the pH of the base solution is 6 to 9, for example: 6, 6.5, 7, 8 or 9, etc., not limited to the listed values, and other unlisted values within this range are also applicable.
[0021] Preferably, in step (1), the first pH is 5 to 7 (e.g., 5, 5.5, 6, 6.5 or 7, etc., not limited to the listed values, other unlisted values within this range are also applicable).
[0022] Preferably, the stirring speed of the nucleation reaction is 500 to 1000 rpm, for example: 500 rpm, 600 rpm, 700 rpm, 800 rpm or 1000 rpm, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0023] Preferably, the temperature of the nucleation reaction is 40 to 60°C, for example: 40°C, 45°C, 50°C, 55°C or 60°C, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0024] Preferably, the endpoint of the nucleation reaction is when the particle size in the system is 2 to 4 μm, for example: 2 μm, 2.5 μm, 3 μm, 3.5 μm or 4 μm, etc., not limited to the listed values, and other unlisted values within this range are also applicable.
[0025] Preferably, in step (2), the second pH is 7 to 9 (e.g., 7, 7.5, 8, 8.5 or 9, etc., not limited to the listed values, other unlisted values within this range are also applicable).
[0026] Preferably, the stirring speed of the growth reaction is 500 to 1000 rpm, for example: 500 rpm, 600 rpm, 700 rpm, 800 rpm or 1000 rpm, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0027] Preferably, the temperature of the growth reaction is 40 to 60°C, for example: 40°C, 45°C, 50°C, 55°C or 60°C, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0028] Preferably, the growth reaction described in step (2) is followed by filtration, washing, and drying.
[0029] Preferably, the number of water washes is 3 to 7 times, for example: 3 times, 4 times, 5 times, 6 times or 7 times, etc.
[0030] Preferably, the drying temperature is 80 to 130°C, for example: 80°C, 90°C, 100°C, 120°C or 130°C, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0031] In a second aspect, the present invention provides a lithium-rich manganese-based nickel-manganese carbonate precursor, which is prepared by the method described in the first aspect.
[0032] Preferably, the diameter-to-diameter ratio (D90-D10) / D50 of the lithium-rich manganese-based nickel-manganese carbonate precursor is 0.4 to 0.6, for example: 0.4, 0.45, 0.5, 0.55 or 0.6, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0033] Preferably, the tap density of the lithium-rich manganese-based nickel-manganese carbonate precursor is 1.8–2.4 g / cm³. 3 For example: 1.8g / cm 3 1.9g / cm 3 2g / cm 3 2.2g / cm 3 Or 2.4g / cm 3 The term "etc." is not limited to the listed values; it also applies to other unlisted values within the range.
[0034] Preferably, the specific surface area of the lithium-rich manganese-based nickel-manganese carbonate precursor is 100–150 m². 2 / g, for example: 100m 2 / g、110m 2 / g、120m 2 / g, 140m 2 / g or 150m 2 / g, etc., are not limited to the listed values; other unlisted values within this range also apply.
[0035] Thirdly, the present invention provides a lithium-rich manganese-based cathode material, which is prepared by mixing and sintering a lithium-rich manganese-based nickel-manganese carbonate precursor as described in the second aspect with a lithium source.
[0036] Preferably, the lithium source includes lithium hydroxide and / or lithium carbonate.
[0037] Fourthly, the present invention provides a lithium-ion battery comprising the lithium-rich manganese-based cathode material as described in the third aspect.
[0038] Compared with the prior art, the present invention has the following beneficial effects:
[0039] (1) This invention uses carbonate as a precipitant. By adjusting the pH during the nucleation and growth stages, nickel-manganese co-precipitation reaction can be achieved to prepare a product with high sphericity, uniform particle distribution, mild reaction conditions, simple operation, and is conducive to industrial production.
[0040] (2) The discharge capacity of the battery made from the lithium-rich manganese-based nickel-manganese carbonate precursor and corresponding cathode material described in this invention can reach more than 246.68 mAh / g, and the capacity retention rate after 100 cycles is more than 90.02%. Attached Figure Description
[0041] Figure 1 This is a SEM image of the lithium-rich manganese-based nickel-manganese carbonate precursor prepared in Example 1.
[0042] Figure 2 This is a SEM image of the lithium-rich manganese-based nickel-manganese carbonate precursor prepared in Comparative Example 1.
[0043] Figure 3 This is a SEM image of the lithium-rich manganese-based nickel-manganese carbonate precursor prepared in Comparative Example 2. Detailed Implementation
[0044] 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.
[0045] Example 1
[0046] This embodiment provides a lithium-rich manganese-based nickel-manganese carbonate precursor, and the preparation method of the lithium-rich manganese-based nickel-manganese carbonate precursor is as follows:
[0047] (1) Prepare a sulfate solution with a molar ratio of Ni:Mn = 0.25:0.75, 100 g / L, and a sodium bicarbonate solution with a molar ratio of 200 g / L. Add pure water and sodium bicarbonate to the reactor as the reaction base liquid. Add the binary liquid and sodium bicarbonate solution to the reactor simultaneously through a peristaltic pump. Set the stirring speed of the reactor to 800 rpm, control the reaction temperature to 42℃, and control the pH between 5.5 and 7.0 to carry out the nucleation reaction.
[0048] (2) When the slurry particle size reaches approximately 3.0 μm, adjust the reaction pH to between 7.5 and 9.0 to carry out the crystal growth reaction. After the reaction, transfer the slurry to a vacuum filtration flask and wash it 5-6 times with pure water. Transfer the solid material obtained from the vacuum filtration and washing to an oven and dry it at 100℃ to finally obtain the lithium-rich manganese-based NM2575 carbonate precursor. Its SEM image is shown below. Figure 1 As shown.
[0049] Example 2
[0050] This embodiment provides a lithium-rich manganese-based nickel-manganese carbonate precursor, and the preparation method of the lithium-rich manganese-based nickel-manganese carbonate precursor is as follows:
[0051] (1) Prepare a sulfate solution of 105 g / L and a sodium carbonate solution of 250 g / L with a molar ratio of Ni:Mn = 0.33:0.67. Add pure water and sodium carbonate to the reactor as the reaction base liquid. Add the binary liquid and sodium carbonate solution to the reactor at the same time through a peristaltic pump. Set the stirring speed of the reactor to 800 rpm, control the reaction temperature to 50℃, and control the pH between 6.0 and 7.5 to carry out the nucleation reaction.
[0052] (2) When the particle size of the slurry reaches about 2.5 μm, adjust the reaction pH to between 8.0 and 9.0 to carry out the crystal growth reaction. After the reaction is completed, transfer the slurry to a vacuum filtration flask and wash it with pure water 5 to 7 times. Transfer the solid material obtained by vacuum filtration and washing to an oven and dry it at 120°C to finally obtain the lithium-rich manganese-based NM3367 carbonate precursor.
[0053] Example 3
[0054] This embodiment provides a lithium-rich manganese-based nickel-manganese carbonate precursor, and the preparation method of the lithium-rich manganese-based nickel-manganese carbonate precursor is as follows:
[0055] (1) Prepare a sulfate solution with a molar ratio of Ni:Mn = 0.35:0.65 of 95 g / L and an ammonium carbonate solution of 250 g / L. Add pure water and sodium carbonate to the reactor as the reaction base liquid. Add the binary liquid and sodium carbonate solution to the reactor at the same time through a peristaltic pump. Set the stirring speed of the reactor to 800 rpm, control the reaction temperature to 56℃, and control the pH between 5.5 and 7.0 to carry out the nucleation reaction.
[0056] (2) When the particle size of the slurry reaches about 3.5 μm, adjust the reaction pH to between 7.0 and 8.5 to carry out the crystal growth reaction. After the reaction is completed, transfer the slurry to a vacuum filtration flask and wash it with pure water 4 to 6 times. Transfer the solid material obtained by vacuum filtration and washing to an oven and dry it at 100°C to finally obtain the lithium-rich manganese-based NM3565 carbonate precursor.
[0057] Example 4
[0058] This embodiment provides a lithium-rich manganese-based nickel-manganese carbonate precursor, and the preparation method of the lithium-rich manganese-based nickel-manganese carbonate precursor is as follows:
[0059] (1) Prepare a sulfate solution of 100 g / L and a sodium carbonate solution of 200 g / L with a molar ratio of Ni:Mn = 0.40:0.60. Add pure water and sodium carbonate to the reactor as the reaction base liquid. Add the binary liquid and sodium carbonate solution to the reactor at the same time through a peristaltic pump. Set the stirring speed of the reactor to 800 rpm, control the reaction temperature to 58℃, and control the pH between 5.0 and 7.0 to carry out the nucleation reaction.
[0060] (2) When the particle size of the slurry reaches about 3μm, adjust the reaction pH to between 7.0 and 8.5 to carry out the crystal growth reaction. After the reaction is completed, transfer the slurry to a vacuum filtration flask and wash it with pure water 4 to 5 times. Transfer the solid material obtained by vacuum filtration and washing to an oven and dry it at 100℃ to finally obtain the lithium-rich manganese-based NM4060 carbonate precursor.
[0061] Example 5
[0062] The difference between this embodiment and Embodiment 1 is that the first pH is 4.5, while the other conditions and parameters are exactly the same as in Embodiment 1.
[0063] Example 6
[0064] The difference between this embodiment and Embodiment 1 is that the first pH is 7.5, while the other conditions and parameters are exactly the same as in Embodiment 1.
[0065] Example 7
[0066] The difference between this embodiment and Example 1 is that the second pH is 6.5, while the other conditions and parameters are exactly the same as in Example 1.
[0067] Example 8
[0068] The difference between this embodiment and Embodiment 1 is that the second pH is 9.5, while the other conditions and parameters are exactly the same as in Embodiment 1.
[0069] Comparative Example 1
[0070] The difference between this comparative example and Example 1 is that the pH of the reaction was controlled between 5.5 and 7.0 throughout the process, while all other conditions and parameters were exactly the same as in Example 1. The SEM image of the obtained precursor is shown below. Figure 2 As shown.
[0071] Comparative Example 2
[0072] The difference between this comparative example and Example 1 is that the pH of the reaction was controlled between 7.5 and 9.0 throughout the process, while all other conditions and parameters were exactly the same as in Example 1. The SEM image of the obtained precursor is shown below. Figure 3 As shown.
[0073] Comparative Example 3
[0074] The difference between this comparative example and Example 1 is that the first pH is 7.5-9.0 and the second pH is 5.5-7.0, while the other conditions and parameters are exactly the same as in Example 1.
[0075] Performance testing:
[0076] The TD, BET, and radial distance of the precursors prepared in the above embodiments and comparative examples were tested.
[0077] The cathode material obtained by sintering the precursor prepared in the above examples and comparative examples with a lithium source was then used to prepare a lithium-ion coin cell battery. The battery was then combined with a lithium sheet, a 5V high-voltage electrolyte, and a polyethylene separator. The electrochemical performance was tested under the conditions of 2.0V-4.6V@0.1C / 0.1C. The test results are shown in Table 1.
[0078] Table 1
[0079]
[0080] As shown in Table 1, and based on Examples 1-4, the method described in this invention is applicable to lithium-rich manganese-based nickel-manganese carbonate precursors of various proportions, and the tap density of the precursors obtained can reach 1.896 g / cm³. 3 The specific surface area can reach 110.49 m². 2 With a diameter of ≥ 0.545 mm and a diameter spacing of ≥ 0.545 mm, the discharge capacity of the battery made from the corresponding cathode material can reach ≥ 246.68 mAh / g, and the capacity retention rate after 100 cycles is ≥ 90.02%.
[0081] A comparison of Examples 1 and 5-6 shows that the first pH value affects the performance of the lithium-rich manganese-based nickel-manganese carbonate precursor described in this invention. Controlling the first pH value between 5 and 7 results in a better performance of the lithium-rich manganese-based nickel-manganese carbonate precursor. If the first pH value is too high, the system becomes highly supersaturated, and the particles tend to agglomerate, leading to faster precursor growth and poor particle size distribution uniformity. If the first pH value is too low, some nickel and manganese may not be able to co-precipitate in the early stages, resulting in irregular particle growth structure in the later stages and affecting the stability of the corresponding cathode.
[0082] A comparison of Examples 1 and 7-8 shows that the second pH value affects the performance of the lithium-rich manganese-based nickel-manganese carbonate precursor during its preparation. Controlling the second pH value between 7 and 9 results in a better-performing lithium-rich manganese-based nickel-manganese carbonate precursor. If the second pH value is too high, some nickel-manganese hydroxide precipitates are formed, affecting the crystallinity and purity of the precursor. If the second pH value is too low, there are more irregular secondary particles, resulting in poor particle size uniformity.
[0083] SEM images of the precursors obtained in Example 1 and Comparative Examples 1-2 are shown below. Figure 1-3 As shown, combined with Figure 1-3 As can be seen from the comparison between Example 1 and Comparative Examples 1-2, the pH control at different reaction stages in the preparation process of the lithium-rich manganese-based carbonate precursor of the present invention has a significant impact on the physicochemical properties of the precursor. If the reaction pH is controlled to be low throughout the process, there are more irregular secondary particles and the particle size distribution uniformity is poor; if the reaction pH is controlled to be high throughout the process, the system is oversaturated, the particles are prone to agglomeration, resulting in the precursor growing too fast, the number of irregular secondary particles increases significantly, and the particle size distribution uniformity is even worse.
[0084] As can be seen from the comparison between Example 1 and Comparative Example 3, in the preparation process of the lithium-rich manganese-based carbonate precursor of the present invention, it is necessary to control the first pH < the second pH. If the first pH > the second pH, the particles grow faster in the early stage of the reaction and small particles burst in the later stage, resulting in irregular precursor structure and poorer uniformity of particle size distribution, which seriously affects the electrochemical performance of the corresponding cathode.
[0085] 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 preparing a lithium-rich manganese-based nickel-manganese carbonate precursor, characterized in that, The preparation method includes the following steps: (1) The nickel-manganese mixed salt solution and the carbonate solution were injected into the bottom liquid in a co-current manner, and the nucleation reaction was carried out at the first pH. (2) Adjust the pH of the reaction system and carry out the growth reaction at the second pH to obtain the lithium-rich manganese-based nickel-manganese carbonate precursor; Wherein, the first pH < the second pH; The base liquid in step (1) is a mixture of water and carbonate; Step (1) The first pH is 5~7; Step (2) The second pH is 7.5~9.
2. The preparation method according to claim 1, characterized in that, The mass concentration of the nickel-manganese mixed salt solution is 80~120g / L.
3. The preparation method according to claim 1, characterized in that, The solute in the carbonate solution in step (1) includes any one or a combination of at least two of sodium carbonate, sodium bicarbonate, potassium carbonate, ammonium bicarbonate, or ammonium carbonate.
4. The preparation method according to claim 1, characterized in that, The mass concentration of the carbonate solution is 50~500g / L.
5. The preparation method according to claim 1, characterized in that, The pH of the base solution is 6-9.
6. The preparation method according to claim 1, characterized in that, The stirring speed for the nucleation reaction is 500~1000 rpm.
7. The preparation method according to claim 1, characterized in that, The nucleation reaction occurs at a temperature of 40~60℃.
8. The preparation method according to claim 1, characterized in that, The endpoint of the nucleation reaction is when the particle size in the system is 2~4μm.
9. The preparation method according to claim 1, characterized in that, The stirring speed for the growth reaction is 500~1000 rpm.
10. The preparation method according to claim 1, characterized in that, The growth reaction is carried out at a temperature of 40~60℃.
11. The preparation method according to claim 1, characterized in that, After the growth reaction described in step (2), the mixture is filtered, washed with water, and dried.
12. The preparation method according to claim 11, characterized in that, The number of times the water is washed is 3 to 7.
13. The preparation method according to claim 11, characterized in that, The drying temperature is 80~130℃.
14. A lithium-rich manganese-based nickel-manganese carbonate precursor, characterized in that, The lithium-rich manganese-based nickel-manganese carbonate precursor is prepared by the method described in any one of claims 1-13.
15. The lithium-rich manganese-based nickel-manganese carbonate precursor as described in claim 14, characterized in that, The diameter-to-diameter ratio (D90-D10) / D50 of the lithium-rich manganese-based nickel-manganese carbonate precursor is 0.4~0.
6.
16. The lithium-rich manganese-based nickel-manganese carbonate precursor as described in claim 14, characterized in that, The tap density of the lithium-rich manganese-based nickel-manganese carbonate precursor is 1.8~2.4 g / cm³. 3 .
17. The lithium-rich manganese-based nickel-manganese carbonate precursor as described in claim 14, characterized in that, The specific surface area of the lithium-rich manganese-based nickel-manganese carbonate precursor is 100~150 m². 2 / g.
18. A lithium-rich manganese-based cathode material, characterized in that, The lithium-rich manganese-based cathode material is prepared by mixing and sintering the lithium-rich manganese-based nickel-manganese carbonate precursor as described in any one of claims 14-17 with a lithium source.
19. A lithium-ion battery, characterized in that, The lithium-ion battery comprises the lithium-rich manganese-based cathode material as described in claim 18.