Production apparatus and method for core-shell precursor having normally distributed particle size

Abstract

A production apparatus and method for a core-shell precursor having a normally distributed particle size. The production apparatus comprises a homogenization reactor (1), a stirring reactor (2), and a thickener (3) that are sequentially connected by means of pipes, and the thickener (3) is connected back to the stirring reactor (2) by means of a pipe, so as to form a material circulation loop. The production apparatus uses a continuous method to produce a core-shell precursor having a normally distributed particle size. In the production method, the homogenization reactor (1) and the stirring reactor (2) are used to synchronously perform a coprecipitation reaction, and the thickener (3) is used to achieve continuous reaction and particle size control, thereby obtaining the core-shell precursor having the normally distributed particle size.

Description

An apparatus and method for producing core-shell precursors with a normally distributed particle size. Technical Field

[0001] This application belongs to the field of battery manufacturing technology, and relates to a method for producing a core-shell precursor, and more particularly to a production apparatus and method for a core-shell precursor with a normally distributed particle size. Background Technology

[0002] With the increasing demand for longer driving ranges in electric vehicles, the requirements for high-range lithium-ion batteries are also gradually increasing. High-nickel cathodes have become a research hotspot due to their superior performance, such as high energy density and high rate capability. However, the thermal instability of high-nickel cathodes leads to frequent battery spontaneous combustion incidents. Therefore, the development of high-nickel core-shell precursors is imperative.

[0003] To improve the compaction density, existing core-shell cathode materials require the separate preparation of large-particle and small-particle core-shell precursors in the precursor stage, which are then blended after sintering, resulting in low efficiency.

[0004] In addition, in order to improve the mass production success rate of the precursor stage, the above method needs to control the reaction time to within 100 hours. Therefore, it is necessary to reduce the number of seed crystals by rapidly lowering the pH in the early stage of the reaction. However, this will cause severe seed crystal agglomeration, thereby reducing the compaction density of the cathode material. Furthermore, irregular particles are more prone to cracking, which in turn leads to a significant reduction in battery cycle performance.

[0005] Therefore, how to provide a production method for core-shell precursors that solves the thermal instability problem of high-nickel cathode materials in the existing technology, while improving the production efficiency and quality of core-shell precursors, and ultimately improving battery performance and safety, has become an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0007] To address the shortcomings of existing technologies, the purpose of this application is to provide a production apparatus and method for core-shell precursors with a normally distributed particle size, which solves the problem of thermal instability of high-nickel cathode materials in existing technologies, while improving the production efficiency and quality of core-shell precursors, ultimately enhancing battery performance and safety, and facilitating large-scale application.

[0008] To achieve this objective, the present application adopts the following technical solution:

[0009] In a first aspect, this application provides a production apparatus for a core-shell precursor with a normally distributed particle size. The production apparatus includes a homogenizing reactor, a stirred reactor, and a thickener connected in sequence by pipelines, and the thickener is connected back to the stirred reactor by pipelines to form a material circulation loop.

[0010] The production apparatus employs a continuous method to produce core-shell precursors with a normally distributed particle size distribution.

[0011] The production apparatus provided in this application realizes continuous production of core-shell precursors through a homogenizing reactor, a stirred reactor, and a thickener connected in sequence. The particle size of the obtained core-shell precursors exhibits a normal distribution, reducing the batch mixing process of cathode materials and significantly improving the production efficiency of precursors. The production apparatus can not only prepare high-nickel core-shells but also lithium-rich manganese-based core-shells, and has broad application prospects.

[0012] In one embodiment, the homogenizing reactor and / or stirred reactor is equipped with an online particle size monitor for online monitoring of the particle size range of the seeds in the homogenizing reactor and the particle size distribution of the seeds in the stirred reactor.

[0013] In this application, the online particle size monitor can be one or more. When there is only one online particle size monitor, the homogenizing reactor and the stirred reactor are connected in parallel to the same online particle size monitor.

[0014] In one embodiment, the homogenizing reactor and / or stirred reactor is equipped with an online pH monitor for online monitoring of the pH value of the mixed solution within the reactor.

[0015] Secondly, this application provides a method for producing a core-shell precursor with a normally distributed particle size using the production apparatus described in the first aspect. The method employs a homogenizing reactor and a stirred reactor to simultaneously carry out a co-precipitation reaction, and uses a thickener to achieve continuous reaction and particle size control, thereby obtaining a core-shell precursor with a normally distributed particle size.

[0016] The production method provided in this application produces high-sphericity precursor particles through the synergistic cooperation of a homogenizing reactor, a stirred reactor, and a thickener. Because the force is more balanced, the compaction density of the cathode material and the energy density of the battery are improved. Furthermore, the high-sphericity cathode material reduces the risk of cracking during battery cycling and significantly improves the cycle performance of the battery.

[0017] In addition, for high-nickel core-shell materials, high sphericity can significantly improve the thermal stability of ternary lithium batteries, thereby enhancing battery safety and lifespan.

[0018] In one implementation, the method includes the following steps:

[0019] (1) Mix nickel salt, cobalt salt, manganese salt and pure water according to the molar ratio Ni:Co:Mn=x1:y1:z1 to obtain the first salt solution;

[0020] (2) Mix nickel salt, cobalt salt, manganese salt and pure water according to the molar ratio Ni:Co:Mn=x2:y2:z2 to obtain a second salt solution;

[0021] (3) The first salt solution, precipitant solution and complexing agent solution are injected into the homogenized reactor to carry out the first coprecipitation reaction. The particle size of the seed kernel is controlled by adjusting the residence time, and the solution is continuously injected into the stirred reactor.

[0022] (4) Inject the second salt solution, precipitant solution and complexing agent solution into the stirred reactor to carry out the second coprecipitation reaction. When the liquid level reaches the concentrated liquid level, turn on the thickener and continue the reaction until the particle size reaches the target requirement. Then, stop the homogenizing reactor and the stirred reactor.

[0023] (5) Collect the materials in the homogenizing reactor and the stirred reactor, and obtain the core-shell precursor with a normal particle size distribution after solid-liquid separation.

[0024] In one embodiment, the molar ratio in step (1) satisfies: x1 + y1 + z1 = 1, and 0.8 < x1 < 0.99, for example, x1 = 0.81, 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96 or 0.98, 0.01 ≤ y1 < 0.1, for example, y1 = 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08 or 0.09, 0.01 < z1 < 0.1, for example, z1 = 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08 or 0.09, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0025] In one implementation, the molar ratio in step (2) satisfies: x² + y² + z² = 1, and 0.5 < x² < 0.8, for example, x² = 0.51, 0.55, 0.6, 0.65, 0.7, 0.75, or 0.79, and 0.01 ≤ y² < 0.4, for example, y² = 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, or 0.39. 0.05 < z2 < 0.25, for example, z2 can be 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23 or 0.24, but is not limited to the listed values, other unlisted values ​​within this range also apply.

[0026] In one embodiment, the nickel salt, cobalt salt and manganese salt mentioned in steps (1) and (2) are any one or at least two combinations of sulfate, nitrate or chloride salts of the corresponding metal ions. Typical but non-limiting combinations include combinations of sulfate and nitrate, nitrate and chloride, sulfate and chloride, or sulfate, nitrate and chloride salts.

[0027] In one embodiment, the total concentration of metal ions in the first salt solution in step (1) and the second salt solution in step (2) is 1.6-2.4 mol / L, for example, it can be 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2 mol / L, 2.1 mol / L, 2.2 mol / L, 2.3 mol / L or 2.4 mol / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] In one embodiment, the precipitant solutions in steps (3) and (4) respectively comprise sodium hydroxide solutions.

[0029] In one embodiment, the concentration of the precipitant solution in steps (3) and (4) is 9-12 mol / L, for example, it can be 9 mol / L, 9.5 mol / L, 10 mol / L, 10.5 mol / L, 11 mol / L, 11.5 mol / L or 12 mol / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] In one embodiment, the complexing agent solutions in steps (3) and (4) respectively comprise ammonia.

[0031] In one embodiment, the concentration of the complexing agent solution in steps (3) and (4) is 8-10 mol / L, for example, it can be 8 mol / L, 8.2 mol / L, 8.4 mol / L, 8.6 mol / L, 8.8 mol / L, 9 mol / L, 9.2 mol / L, 9.4 mol / L, 9.6 mol / L, 9.8 mol / L or 10 mol / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] In one embodiment, during the first coprecipitation reaction in step (3), the injection flow rate of the first salt solution is 4-8 L / h, for example, it can be 4 L / h, 4.5 L / h, 5 L / h, 5.5 L / h, 6 L / h, 6.5 L / h, 7 L / h, 7.5 L / h or 8 L / h; the injection flow rate of the precipitant solution is 2.2-2.6 L / h, for example, it can be 2.2 L / h, 2.3 L / h, 2.4 L / h, 2.5 L / h or 2.6 L / h; and the injection flow rate of the complexing agent solution is 1-1.5 L / h, for example, it can be 1 L / h, 1.1 L / h, 1.2 L / h, 1.3 L / h, 1.4 L / h or 1.5 L / h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] In one implementation, the dwell time in step (3) is 2-2.5h, for example, it can be 2h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] In one embodiment, during the second coprecipitation reaction in step (4), the injection flow rate of the second salt solution is 4-8 L / h, for example, 4 L / h, 4.5 L / h, 5 L / h, 5.5 L / h, 6 L / h, 6.5 L / h, 7 L / h, 7.5 L / h, or 8 L / h; the injection flow rate of the precipitant solution is 2.2-2.4 L / h, for example, 2.2 L / h, 2.3 L / h, or 2.4 L / h; and the injection flow rate of the complexing agent solution is 0.6-1.2 L / h, for example, 0.6 L / h. The flow rates are 0.7 L / h, 0.8 L / h, 0.9 L / h, 1 L / h, 1.1 L / h, or 1.2 L / h, and the pH of the mixed solution is maintained at 9-13, for example, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, or 13, and the ammonia concentration is 3-6 g / L, for example, 3 g / L, 3.5 g / L, 4 g / L, 4.5 g / L, 5 g / L, 5.5 g / L, or 6 g / L, but not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0035] In one embodiment, the target particle size requirement in step (4) is D50 ≥ 8 μm, for example, it can be 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm or 12 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0036] In one embodiment, the temperatures of the first coprecipitation reaction in step (3) and the second coprecipitation reaction in step (4) are 40-65°C, for example, 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C or 65°C, but are not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] In one embodiment, step (3) the first coprecipitation reaction and step (4) the second coprecipitation reaction are carried out in a protective gas atmosphere, wherein the protective gas includes nitrogen.

[0038] In one embodiment, the solid-liquid separation in step (5) includes centrifugation, washing, and drying.

[0039] In one embodiment, step (5) further includes the removal of magnetic foreign matter after solid-liquid separation.

[0040] As an optional technical solution of the second aspect of this application, the method employs a homogenized reactor and a stirred reactor to simultaneously carry out a co-precipitation reaction, and uses a thickener to achieve continuous reaction and particle size control, obtaining a core-shell precursor with a normally distributed particle size, specifically including the following steps:

[0041] (1) A first salt solution with a total metal ion concentration of 1.6-2.4 mol / L is obtained by mixing nickel salt, cobalt salt, manganese salt and pure water according to the molar ratio Ni:Co:Mn=x1:y1:z1; the molar ratio satisfies: x1+y1+z1=1, and 0.8<x1<0.99, 0.01≤y1<0.1, 0.01<z1<0.1;

[0042] (2) Nickel salt, cobalt salt, manganese salt and pure water are mixed according to the molar ratio Ni:Co:Mn=x2:y2:z2 to obtain a second salt solution with a total metal ion concentration of 1.6-2.4 mol / L; the molar ratio satisfies: x2+y2+z2=1, and 0.5<x2<0.8, 0.01≤y2<0.4, 0.05<z2<0.25;

[0043] (3) The first salt solution, precipitant solution and complexing agent solution are injected into the homogenizing reactor, and the injection flow rate of the first salt solution is controlled at 4-8 L / h, the injection flow rate of the precipitant solution is 2.2-2.6 L / h, and the injection flow rate of the complexing agent solution is 1-1.5 L / h. The first coprecipitation reaction is carried out at 40-65℃ in a nitrogen atmosphere. The particle size of the seed core is controlled by adjusting the residence time to 2-2.5h, and the solution is continuously injected into the stirred reactor.

[0044] (4) Inject the second salt solution, precipitant solution and complexing agent solution into the stirred reactor, and control the injection flow rate of the second salt solution to be 4-8 L / h, the injection flow rate of the precipitant solution to be 2.2-2.4 L / h, and the injection flow rate of the complexing agent solution to be 0.6-1.2 L / h. At the same time, maintain the pH of the mixed solution at 9-13 and the ammonia concentration at 3-6 g / L. Carry out the second coprecipitation reaction at 40-65℃ in a nitrogen atmosphere. When the liquid level reaches the concentrated liquid level, turn on the thickener and continue the reaction until the particle size D50≥8μm. Then, stop the homogenizing reactor and the stirred reactor.

[0045] (5) Collect the materials from the homogenizing reactor and the stirred reactor, then centrifuge, wash and dry them to remove magnetic foreign matter and obtain a core-shell precursor with a normal particle size distribution.

[0046] Wherein, the nickel salt, cobalt salt and manganese salt mentioned in steps (1) and (2) are any one or at least two combinations of sulfate, nitrate or chloride salts of the corresponding metal ions; the precipitant solutions mentioned in steps (3) and (4) respectively include sodium hydroxide solution with a concentration of 9-12 mol / L, and the complexing agent solutions respectively include ammonia water with a concentration of 8-10 mol / L.

[0047] The numerical range described in this application includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, this application will not exhaustively list the specific point values ​​included in the range.

[0048] Compared with the prior art, this application has the following advantages:

[0049] (1) The production apparatus provided in this application realizes the continuous production of core-shell precursors through a homogenizing reactor, a stirring reactor and a thickener connected in sequence, and the particle size of the obtained core-shell precursors is normally distributed, which reduces the batch mixing process of cathode materials and greatly improves the production efficiency of precursors. The production apparatus can not only prepare high-nickel core-shells, but also prepare lithium-rich manganese-based core-shells, and has a wide range of application prospects.

[0050] (2) The production method provided in this application produces high sphericity precursor particles through the synergistic cooperation between a homogenizing reactor, a stirred reactor and a thickener. Because the force is more balanced, the compaction density of the cathode material and the energy density of the battery are improved. Moreover, the high sphericity cathode material reduces the risk of cracking during battery cycling and significantly improves the cycle performance of the battery.

[0051] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood. Attached Figure Description

[0052] The accompanying drawings are used to provide a further understanding of the technical solutions in this paper and form part of the specification. They are used together with the embodiments of this application to explain the technical solutions in this paper and do not constitute a limitation on the technical solutions in this paper.

[0053] Figure 1 is a schematic diagram of the production apparatus for the core-shell precursor with a normally distributed particle size provided in this application;

[0054] Figure 2 is a transmission electron microscope image of the core-shell precursor obtained by the production method provided in Example 1.

[0055] Wherein: 1-homogenizing reactor; 2-stirred reactor; 3-thickener. Detailed Implementation

[0056] The technical solution of this application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely to help understand this application and should not be regarded as specific limitations on this application.

[0057] This application provides a production apparatus for a core-shell precursor with a normally distributed particle size, as shown in Figure 1. The production apparatus includes a homogenizing reactor 1, a stirred reactor 2, and a thickener 3 connected in sequence by pipelines, and the thickener 3 is connected back to the stirred reactor 2 by pipelines to form a material circulation loop. The production apparatus uses a continuous method to produce a core-shell precursor with a normally distributed particle size.

[0058] In this application, the homogenizing reactor 1 is equipped with an online particle size monitor, and the stirred reactor 2 is equipped with an online pH monitor (not shown in the figure).

[0059] Example 1

[0060] This embodiment provides a method for producing a core-shell precursor with a normally distributed particle size using the above-mentioned production apparatus. The method employs a homogenizing reactor 1 and a stirred reactor 2 to simultaneously carry out a co-precipitation reaction, and uses a thickener 3 to achieve continuous reaction and particle size control, thereby obtaining a core-shell precursor with a normally distributed particle size. The method specifically includes the following steps:

[0061] (1) Nickel sulfate, cobalt sulfate, manganese sulfate and pure water were mixed in a molar ratio of Ni:Co:Mn = 0.9:0.05:0.05 to obtain a first salt solution with a total metal ion concentration of 2 mol / L.

[0062] (2) Nickel sulfate, cobalt sulfate, manganese sulfate and pure water were mixed according to the molar ratio Ni:Co:Mn=0.65:0.2:0.15 to obtain a second salt solution with a total metal ion concentration of 2mol / L;

[0063] (3) The first salt solution, the sodium hydroxide solution with a concentration of 10 mol / L and the ammonia solution with a concentration of 10 mol / L were injected into the homogenizing reactor 1. The injection flow rate of the first salt solution was controlled to be 6 L / h, the injection flow rate of the sodium hydroxide solution was 2.3 L / h and the injection flow rate of the ammonia solution was 1 L / h. The first coprecipitation reaction was carried out at 52°C in a nitrogen atmosphere. The particle size of the seed core was controlled by adjusting the residence time to 2.17 h and the solution was continuously injected into the stirred reactor 2.

[0064] (4) Inject the second salt solution, a sodium hydroxide solution with a concentration of 10 mol / L and an ammonia solution with a concentration of 10 mol / L into the stirred reactor 2, and control the injection flow rate of the second salt solution to 6 L / h, the injection flow rate of the sodium hydroxide solution to 1.95 L / h, and the injection flow rate of the ammonia solution to 1.0 L / h. At the same time, maintain the pH of the mixed solution at 10±0.5 and the ammonia concentration at 4±0.5 g / L. Carry out the second coprecipitation reaction at 50°C in a nitrogen atmosphere. When the liquid level reaches the concentrated liquid level, turn on the thickener and continue the reaction until the particle size D50≥8μm. Then, stop the homogenizing reactor 1 and the stirred reactor 2.

[0065] (5) Collect the materials in the homogenizing reactor 1 and the stirred reactor 2, then centrifuge, wash and dry them to remove magnetic foreign matter and obtain a core-shell precursor with a normal particle size distribution.

[0066] Figure 2 is a transmission electron microscope image of the core-shell precursor obtained in this embodiment.

[0067] As shown in Figure 2, the particle size of the core-shell precursor obtained in this embodiment is normally distributed, and its sphericity is significantly higher than that of the precursor obtained by the traditional preparation method.

[0068] Example 2

[0069] This embodiment provides a method for producing a core-shell precursor with a normally distributed particle size using the above-mentioned production apparatus. The method employs a homogenizing reactor 1 and a stirred reactor 2 to simultaneously carry out a co-precipitation reaction, and uses a thickener 3 to achieve continuous reaction and particle size control, thereby obtaining a core-shell precursor with a normally distributed particle size. The method specifically includes the following steps:

[0070] (1) Nickel nitrate, cobalt nitrate, manganese nitrate and pure water were mixed in a molar ratio of Ni:Co:Mn = 0.85:0.09:0.06 to obtain a first salt solution with a total metal ion concentration of 1.6 mol / L;

[0071] (2) Nickel nitrate, cobalt nitrate, manganese nitrate and pure water were mixed in a molar ratio of Ni:Co:Mn = 0.6:0.2:0.2 to obtain a second salt solution with a total metal ion concentration of 1.6 mol / L;

[0072] (3) The first salt solution, the sodium hydroxide solution with a concentration of 9 mol / L and the ammonia solution with a concentration of 8 mol / L were injected into the homogenizing reactor 1. The injection flow rate of the first salt solution was controlled to be 8 L / h, the injection flow rate of the sodium hydroxide solution was 2.6 L / h and the injection flow rate of the ammonia solution was 1.5 L / h. The first coprecipitation reaction was carried out at 65°C in a nitrogen atmosphere. The particle size of the seed core was controlled by adjusting the residence time to 1.63 h. The solution was continuously injected into the stirred reactor 2.

[0073] (4) Inject the second salt solution, a sodium hydroxide solution with a concentration of 9 mol / L and an ammonia solution with a concentration of 8 mol / L into the stirred reactor 2, and control the injection flow rate of the second salt solution to 8 L / h, the injection flow rate of the sodium hydroxide solution to 2.4 L / h, and the injection flow rate of the ammonia solution to 1.2 L / h. At the same time, maintain the pH of the mixed solution at 10±1 and the ammonia concentration at 5±1 g / L. Carry out the second coprecipitation reaction at 60℃ in a nitrogen atmosphere. When the liquid level reaches the concentrated liquid level, turn on the thickener 3 and continue the reaction until the particle size D50≥8μm. Then, stop the homogenizing reactor 1 and the stirred reactor 2.

[0074] (5) Collect the materials in the homogenizing reactor 1 and the stirred reactor 2, then centrifuge, wash and dry them to remove magnetic foreign matter and obtain a core-shell precursor with a normal particle size distribution.

[0075] The particle size distribution and sphericity of the core-shell precursor obtained in this embodiment are similar to those in Example 1, so they will not be described again here.

[0076] Example 3

[0077] This embodiment provides a method for producing a core-shell precursor with a normally distributed particle size using the above-mentioned production apparatus. The method employs a homogenizing reactor 1 and a stirred reactor 2 to simultaneously carry out a co-precipitation reaction, and uses a thickener 3 to achieve continuous reaction and particle size control, thereby obtaining a core-shell precursor with a normally distributed particle size. The method specifically includes the following steps:

[0078] (1) Nickel chloride, cobalt chloride, manganese chloride and pure water were mixed in a molar ratio of Ni:Co:Mn = 0.95:0.01:0.04 to obtain a first salt solution with a total metal ion concentration of 2.4 mol / L;

[0079] (2) Nickel chloride, cobalt chloride, manganese chloride and pure water were mixed in a molar ratio of Ni:Co:Mn = 0.7:0.15:0.15 to obtain a second salt solution with a total metal ion concentration of 2.4 mol / L.

[0080] (3) The first salt solution, the sodium hydroxide solution with a concentration of 12 mol / L and the ammonia solution with a concentration of 10 mol / L were injected into the homogenizing reactor 1. The injection flow rate of the first salt solution was controlled to be 4 L / h, the injection flow rate of the sodium hydroxide solution was 1.1 L / h and the injection flow rate of the ammonia solution was 1.2 L / h. The first coprecipitation reaction was carried out at 45°C in a nitrogen atmosphere. The particle size of the seed core was controlled by adjusting the residence time to 3.17 h. The solution was continuously injected into the stirred reactor 2.

[0081] (4) Inject the second salt solution, a sodium hydroxide solution with a concentration of 12 mol / L and an ammonia solution with a concentration of 10 mol / L into the stirred reactor 2, and control the injection flow rate of the second salt solution to 4 L / h, the injection flow rate of the sodium hydroxide solution to 1.05 L / h, and the injection flow rate of the ammonia solution to 0.8 L / h. At the same time, maintain the pH of the mixed solution at 10.5±0.7 and the ammonia concentration at 4±1 g / L. Carry out the second coprecipitation reaction at 45℃ in a nitrogen atmosphere. When the liquid level reaches the concentrated liquid level, turn on the thickener 3 and continue the reaction until the particle size D50≥8μm. Then, stop the homogenizing reactor 1 and the stirred reactor 2.

[0082] (5) Collect the materials in the homogenizing reactor 1 and the stirred reactor 2, then centrifuge, wash and dry them to remove magnetic foreign matter and obtain a core-shell precursor with a normal particle size distribution.

[0083] The particle size distribution and sphericity of the core-shell precursor obtained in this embodiment are similar to those in Example 1, so they will not be described again here.

[0084] Performance testing

[0085] The core-shell precursors obtained in Examples 1-3 were subjected to solid-state sintering to prepare the corresponding cathode materials. The obtained cathode materials were then used to fabricate battery electrodes and coin cells. The specific process is as follows:

[0086] (1) Lithium carbonate and core-shell precursor were mixed evenly and sintered in stages. The first stage was sintering at 400℃ for 4 hours and the second stage was sintering at 800℃ for 8 hours to obtain the cathode material.

[0087] (2) The positive electrode material, acetylene black and polyvinylidene fluoride were added to N-methyl-2-pyridinyl ketone in a mass ratio of 8:1:1 to prepare a solution, which was then uniformly coated on aluminum foil, dried and stamped into a thin sheet; the resulting battery electrode, sodium element sheet, glass fiber separator, electrolyte (NaClO4) gasket, spring sheet and battery casing were assembled into a button battery in an Ar gas glove box.

[0088] Table 1 below shows the electrochemical performance test data of coin cells prepared using the core-shell precursors obtained in Examples 1-3, respectively.

[0089] Table 1

[0090] Therefore, the production apparatus provided in this application realizes the continuous production of core-shell precursors through a homogenizing reactor, a stirred reactor and a thickener connected in sequence, and the particle size of the obtained core-shell precursors is normally distributed, which reduces the batch mixing process of cathode materials and greatly improves the production efficiency of precursors. The production apparatus can not only prepare high-nickel core-shells, but also prepare lithium-rich manganese-based core-shells, and has broad application prospects.

[0091] Furthermore, the production method provided in this application produces high-sphericity precursor particles through the synergistic cooperation between a homogenizing reactor, a stirred reactor, and a thickener. Because the force is more balanced, the compaction density of the cathode material and the energy density of the battery are improved. Moreover, the high-sphericity cathode material reduces the risk of cracking during battery cycling and significantly improves the cycle performance of the battery.

[0092] The applicant declares that the above description is only a specific implementation of this application, but the protection scope of this application 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 scope of the technology disclosed in this application fall within the protection and disclosure scope of this application.

Claims

1. A production apparatus for a core-shell precursor with a normal particle size distribution, comprising a homogenizing reactor, a stirred reactor and a thickener connected in sequence by pipelines, wherein the thickener is connected back to the stirred reactor by pipelines to form a material circulation loop; The production apparatus employs a continuous method to produce core-shell precursors with a normally distributed particle size distribution.

2. The production apparatus according to claim 1, wherein, The homogenizing reactor and / or stirred reactor are equipped with an online particle size monitor; Optionally, the homogenizing reactor and / or stirred reactor is equipped with an online pH monitor.

3. A method for producing a core-shell precursor with a normally distributed particle size using the production apparatus as described in claim 1 or 2, wherein a co-precipitation reaction is carried out simultaneously in a homogenizing reactor and a stirred reactor, and a thickener is used to achieve continuous reaction and particle size control, thereby obtaining a core-shell precursor with a normally distributed particle size.

4. The method according to claim 3, wherein, The method includes the following steps: (1) Mix nickel salt, cobalt salt, manganese salt and pure water according to the molar ratio Ni:Co:Mn=x1:y1:z1 to obtain the first salt solution; (2) Mix nickel salt, cobalt salt, manganese salt and pure water according to the molar ratio Ni:Co:Mn=x2:y2:z2 to obtain a second salt solution; (3) The first salt solution, precipitant solution and complexing agent solution are injected into the homogenized reactor to carry out the first coprecipitation reaction. The particle size of the seed kernel is controlled by adjusting the residence time, and the solution is continuously injected into the stirred reactor. (4) Inject the second salt solution, precipitant solution and complexing agent solution into the stirred reactor to carry out the second coprecipitation reaction. When the liquid level reaches the concentrated liquid level, turn on the thickener and continue the reaction until the particle size reaches the target requirement. Then, stop the homogenizing reactor and the stirred reactor. (5) Collect the materials in the homogenizing reactor and the stirred reactor, and obtain the core-shell precursor with a normal particle size distribution after solid-liquid separation.

5. The method according to claim 4, wherein, The molar ratio described in step (1) satisfies: x1+y1+z1=1, and 0.8<x1<0.99, 0.01≤y1<0.1, 0.01<z1<0.1; Optionally, the molar ratio in step (2) satisfies: x2+y2+z2=1, and 0.5<x2<0.8, 0.01≤y2<0.4, 0.05<z2<0.

25.

6. The method according to claim 4 or 5, wherein, The nickel salt, cobalt salt, and manganese salt mentioned in steps (1) and (2) are any one or a combination of at least two of the sulfate, nitrate, or chloride salts of the corresponding metal ions; Optionally, the total concentration of metal ions in the first salt solution in step (1) and the second salt solution in step (2) are 1.6-2.4 mol / L, respectively.

7. The method according to any one of claims 4-6, wherein, The precipitant solutions in steps (3) and (4) respectively include sodium hydroxide solution; Optionally, the concentrations of the precipitant solutions in steps (3) and (4) are 9-12 mol / L, respectively; Optionally, the complexing agent solutions in steps (3) and (4) respectively include ammonia water; Optionally, the concentrations of the complexing agent solutions in steps (3) and (4) are 8-10 mol / L, respectively.

8. The method according to any one of claims 4-7, wherein, In step (3), during the first coprecipitation reaction, the injection flow rate of the first salt solution is 4-8 L / h, the injection flow rate of the precipitant solution is 2.2-2.6 L / h, and the injection flow rate of the complexing agent solution is 1-1.5 L / h. Optionally, the dwell time in step (3) is 2-2.5 hours; Optionally, in step (4) during the second coprecipitation reaction, the injection flow rate of the second salt solution is 4-8 L / h, the injection flow rate of the precipitant solution is 2.2-2.4 L / h, the injection flow rate of the complexing agent solution is 0.6-1.2 L / h, and the pH of the mixed solution is maintained at 9-13 and the ammonia concentration is 3-6 g / L. Optionally, the target particle size requirement in step (4) is D50 ≥ 8 μm; Optionally, the temperatures of the first coprecipitation reaction in step (3) and the second coprecipitation reaction in step (4) are 40-65℃, respectively; Optionally, the first coprecipitation reaction in step (3) and the second coprecipitation reaction in step (4) are carried out in a protective gas atmosphere, and the protective gas includes nitrogen.

9. The method according to any one of claims 4-8, wherein, The solid-liquid separation in step (5) includes centrifugation, washing, and drying; Optionally, step (5) may further include the removal of magnetic foreign matter after solid-liquid separation.

10. The method according to any one of claims 3-9, wherein, The method employs a homogenized reactor and a stirred reactor to simultaneously carry out a co-precipitation reaction, and uses a thickener to achieve continuous reaction and particle size control, obtaining a core-shell precursor with a normally distributed particle size. Specifically, it includes the following steps: (1) A first salt solution with a total metal ion concentration of 1.6-2.4 mol / L is obtained by mixing nickel salt, cobalt salt, manganese salt and pure water according to the molar ratio Ni:Co:Mn=x1:y1:z1; the molar ratio satisfies: x1+y1+z1=1, and 0.8<x1<0.99, 0.01≤y1<0.1, 0.01<z1<0.1; (2) Nickel salt, cobalt salt, manganese salt and pure water are mixed according to the molar ratio Ni:Co:Mn=x2:y2:z2 to obtain a second salt solution with a total metal ion concentration of 1.6-2.4 mol / L; the molar ratio satisfies: x2+y2+z2=1, and 0.5<x2<0.8, 0.01≤y2<0.4, 0.05<z2<0.25; (3) The first salt solution, precipitant solution and complexing agent solution are injected into the homogenizing reactor, and the injection flow rate of the first salt solution is controlled at 4-8 L / h, the injection flow rate of the precipitant solution is 2.2-2.6 L / h, and the injection flow rate of the complexing agent solution is 1-1.5 L / h. The first coprecipitation reaction is carried out at 40-65℃ in a nitrogen atmosphere. The particle size of the seed core is controlled by adjusting the residence time to 2-2.5h, and the solution is continuously injected into the stirred reactor. (4) Inject the second salt solution, precipitant solution and complexing agent solution into the stirred reactor, and control the injection flow rate of the second salt solution to be 4-8 L / h, the injection flow rate of the precipitant solution to be 2.2-2.4 L / h, and the injection flow rate of the complexing agent solution to be 0.6-1.2 L / h. At the same time, maintain the pH of the mixed solution at 9-13 and the ammonia concentration at 3-6 g / L. Carry out the second coprecipitation reaction at 40-65℃ in a nitrogen atmosphere. When the liquid level reaches the concentrated liquid level, turn on the thickener and continue the reaction until the particle size D50≥8μm. Then, stop the homogenizing reactor and the stirred reactor. (5) Collect the materials in the homogenizing reactor and the stirred reactor, then centrifuge, wash and dry them to remove magnetic foreign matter and obtain a core-shell precursor with a normal particle size distribution. Wherein, the nickel salt, cobalt salt and manganese salt mentioned in steps (1) and (2) are any one or at least two combinations of sulfate, nitrate or chloride salts of the corresponding metal ions; the precipitant solutions mentioned in steps (3) and (4) respectively include sodium hydroxide solution with a concentration of 9-12 mol / L, and the complexing agent solutions respectively include ammonia water with a concentration of 8-10 mol / L.

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