High-nickel ternary precursor based on spray pyrolysis method and preparation method and application thereof

Abstract

The invention provides a high-nickel ternary precursor based on a spray pyrolysis method as well as a preparation method and application thereof, the preparation method comprises the following steps: performing spray pyrolysis on a high-nickel ternary solution, and atomizing the high-nickel ternary solution by adopting supercritical CO2 to obtain the high-nickel ternary precursor based on the spray pyrolysis method; the high-nickel ternary liquid comprises a surface active agent. According to the preparation method, supercritical CO2 replaces air to serve as atomizing gas for spray pyrolysis, the size of atomized liquid drops is reduced by means of the super diffusivity and zero surface tension characteristics of the supercritical CO2, meanwhile, a surfactant is added into a precursor solution, the problems that the liquid drops are thick and large and the particle size distribution is wide in the traditional spray pyrolysis process are solved, and the preparation method is suitable for large-scale industrial production. And the high-nickel ternary precursor oxide particles with uniform particle size are prepared.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and relates to a high-nickel ternary precursor based on spray pyrolysis, a preparation method and an application thereof. Background Art

[0002] As an efficient and clean energy storage technology, lithium-ion power batteries have become a key development direction due to their high energy density, long cycle life and low self-discharge rate. In order to adapt to the rapidly developing electric vehicle market, lithium-ion power batteries are developing towards high nickel and high energy density. Therefore, there is an urgent industrial need for practical synthetic methods to mass-produce high-nickel precursors of lithium-ion cathode materials. Traditional preparation methods for ternary precursors such as co-precipitation method and solid-phase method have problems such as uneven composition distribution, wide particle size distribution and complex process in the finished materials. As an emerging material preparation technology, spray pyrolysis has advantages such as short reaction time, uniform composition and controllable particle morphology, and has gradually become a research hotspot for preparing ternary precursors.

[0003] For example, CN 118545772A discloses a ternary precursor with uniform particle size, a cathode material, a preparation method and an application thereof. The preparation method includes the following steps: spray pyrolyzing a metal salt solution to obtain a ternary precursor with uniform particle size; the metal salt solution includes a metal salt, a doping salt, an organic carbon source and a surfactant; the organic carbon source is urea; the surfactant is ethylene glycol and / or N,N-dimethylformamide. It realizes the preparation of the ternary precursor by spray pyrolysis, the preparation process is simple, and the preparation cost of the precursor is reduced; moreover, through the cooperation of a specific organic carbon source and a surfactant, the problem of uneven spray pyrolysis is solved, the generation of hollow spheres is reduced, and the tap density is increased, which is beneficial to improving the electrochemical performance of the corresponding cathode material.

[0004] For another example, CN118412461A discloses a coated ternary cathode material, a preparation method and an application thereof. The coated ternary cathode material includes a lithium nickel cobalt manganese oxide core and a coating layer; the chemical formula of the lithium nickel cobalt manganese oxide core is: LiNi x Co y Mn z M 1-x-y-z O2, M is a doping element, including Ca and / or La; the coating layer is an inert shell co-coated with a metal oxide and a metal fluoride; the preparation method adopts a two-fluid spray pyrolysis process. This method precisely controls the particle morphology, improves the element distribution uniformity, enhances the electrochemical performance and cycle performance of the cathode material, reduces the manufacturing cost, shortens the production time, and minimizes the adverse impact of the production process on the environment, which is beneficial to large-scale popularization and application.

[0005] Although spray pyrolysis has advantages such as short reaction time, uniform composition of the prepared ternary precursor, and controllable particle morphology, flame spray pyrolysis requires a high pyrolysis temperature, which increases the cost of industrial production and has certain safety hazards. Using two-fluid spray pyrolysis can reduce the pyrolysis temperature, thereby reducing the preparation cost. However, currently, air is used as the atomizing gas in the two-fluid spray gun. The ternary liquid has poor diffusivity and large surface tension in the air, resulting in large atomized droplets and a wide particle size distribution of the pyrolyzed metal oxide.

[0006] Based on the above research, there is a need to provide a method for preparing a high-nickel ternary precursor, and the preparation method can obtain high-nickel ternary precursor oxide particles with uniform particle sizes. Summary of the Invention

[0007] The purpose of the present invention is to provide a high-nickel ternary precursor, a preparation method and an application based on spray pyrolysis. The preparation method uses supercritical CO2 instead of air as the atomizing gas for spray pyrolysis. By utilizing the super-diffusivity and zero surface tension characteristics of supercritical CO2, the size of the atomized droplets is reduced. At the same time, a surfactant is added to the precursor solution to solve the problems of large droplets and wide particle size distribution during traditional spray pyrolysis, and high-nickel ternary precursor oxide particles with uniform particle sizes are prepared.

[0008] To achieve the purpose of this invention, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a method for preparing a high-nickel ternary precursor based on spray pyrolysis, and the preparation method includes the following steps:

[0010] Performing spray pyrolysis on the high-nickel ternary liquid, wherein the high-nickel ternary liquid is atomized by supercritical CO2 to obtain the high-nickel ternary precursor based on spray pyrolysis;

[0011] The high-nickel ternary liquid includes a surfactant.

[0012] Problems such as complex process, long reaction time, and difficulty in controlling the component uniformity exist in the preparation of ternary precursors by traditional coprecipitation method, and impurities are easily introduced. And usually multiple-step reactions and post-treatments are required, and the production process is complex. Spray pyrolysis uses each droplet as a microreactor, and a series of processes such as solvent evaporation, solute precipitation, diffusion, decomposition, reaction, and particle agglomeration and sintering occur, and ternary oxide precursors can be prepared quickly and in large quantities.

[0013] In the present invention, supercritical CO2 is used instead of air as the atomizing gas. By utilizing the super-diffusivity and zero surface tension characteristics of supercritical CO2, the size of the atomized droplets is reduced, and the uniformity of the particle size distribution is improved. At the same time, a surfactant is added to the high-nickel ternary solution in the present invention to reduce the interfacial tension between the supercritical CO2 and the solution, promoting the formation of small droplets, thereby obtaining a high-nickel ternary precursor with a narrow particle size distribution range and a uniform particle size distribution.

[0014] Preferably, the pressure for atomizing the high-nickel ternary solution with supercritical CO2 is 0.1 MPa - 0.5 MPa. For example, it can be 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, or 0.5 MPa, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0015] The pressure for spray atomizing the high-nickel ternary solution in the present invention will affect the size of the final primary particles. If the pressure is too small, the particle size of the primary particles will be too large, and the process time for post-treatment crushing will be prolonged. If the pressure is too large, the particle size of the primary particles will be too small, failing to meet the target requirements.

[0016] Preferably, in a two-fluid spray gun, supercritical CO2 is used to atomize the high-nickel ternary solution.

[0017] Preferably, the surfactant includes a perfluoropolyether surfactant.

[0018] The present invention preferably uses a perfluoropolyether surfactant. Since most ionic or polar surfactants (such as sodium dodecyl sulfate SDS, Triton X-100) are almost insoluble in supercritical CO2 and cannot form micelles, the perfluoropolyether surfactant has a better polarity match with supercritical CO2 compared to other surfactants, with higher affinity and solubility in supercritical CO2, increasing the contact angle between the high-nickel ternary solution and supercritical CO2, reducing the particle size of the atomized droplets, and making the obtained product particle size distribution more uniform.

[0019] Preferably, in the high-nickel ternary solution, the content of the surfactant is 0.1 wt% - 0.5 wt%. For example, it can be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, or 0.5 wt%, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0020] The present invention preferably adds an appropriate content of the surfactant. If the addition amount is too small, the effect will be reduced; if the addition amount is too large, the atomized droplets will be too small, and the formed oxide particles will be too small, failing to meet the target requirements.

[0021] Preferably, the high-nickel ternary solution is doped with zirconium ions.

[0022] Preferably, in the high-nickel ternary liquid, the concentration of zirconium ions is 0.1 mol% - 0.2 mol%, for example, it can be 0.1 mol%, 0.12 mol%, 0.14 mol%, 0.16 mol%, 0.18 mol% or 0.2 mol%, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0023] Preferably, the volume ratio of the supercritical CO2 to the high-nickel ternary liquid is (2.5 - 4):1, for example, it can be 2.5:1, 3:1, 3.5:1 or 4:1, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0024] Preferably, the temperature for atomizing the high-nickel ternary liquid with supercritical CO2 is 35°C - 40°C, for example, it can be 35°C, 37°C, 39°C or 40°C, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0025] Preferably, the concentration of the high-nickel ternary liquid is 150 g / L - 160 g / L, for example, it can be 150 g / L, 152 g / L, 154 g / L, 156 g / L or 160 g / L, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0026] Preferably, in the high-nickel ternary liquid, the molar ratio of nickel ions, cobalt ions and manganese ions is (0.65 - 0.85):(0.03 - 0.1):(0.12 - 0.32), for example, it can be 0.65:0.03:0.32, 0.7:0.05:0.25, 0.75:0.07:0.18 or 0.85:0.03:0.12, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0027] The high-nickel ternary liquid of the present invention is prepared by first configuring a mixed salt solution of nickel salt, manganese salt and cobalt salt, and then adding zirconium salt. The nickel salt, manganese salt, cobalt salt and zirconium salt are each independently any one or at least two combinations of nitrate, sulfate or chloride, and the type of zirconium salt is the same as that of the nickel salt, manganese salt and cobalt salt.

[0028] Preferably, the temperature of the spray pyrolysis is 500°C - 700°C, for example, it can be 500°C, 550°C, 600°C, 650°C or 700°C, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0029] Preferably, the time of the spray pyrolysis is 5 s - 10 s, for example, it can be 5 s, 7 s, 9 s or 10 s, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0030] In a second aspect, the present invention provides a high-nickel ternary precursor based on spray pyrolysis, and the high-nickel ternary precursor based on spray pyrolysis is prepared by using the preparation method described in the first aspect.

[0031] Preferably, the particle size D50 of the high-nickel ternary precursor based on spray pyrolysis is 0.5 μm - 6 μm, for example, it can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm or 6 μm, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0032] Preferably, the particle size distribution width Span of the high-nickel ternary precursor based on spray pyrolysis is 0.7 - 2.0, for example, it can be 0.7, 1, 1.25, 1.5, 1.75 or 2.0, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0033] In a third aspect, the present invention provides a high-nickel cathode material, and the raw materials for preparing the high-nickel cathode material include the high-nickel ternary precursor based on spray pyrolysis described in the second aspect.

[0034] In a fourth aspect, the present invention provides a lithium-ion battery, and the lithium-ion battery includes the high-nickel cathode material described in the third aspect.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] In the present invention, supercritical CO2 is used instead of air as the atomizing gas. By utilizing the super-diffusivity and zero surface tension characteristics of supercritical CO2, the size of the atomized droplets is reduced, and the uniformity of the particle size distribution is improved. At the same time, a surfactant is added to the high-nickel ternary solution in the present invention to reduce the interfacial tension between supercritical CO2 and the solution and promote the formation of small droplets, thereby obtaining a high-nickel ternary precursor with a narrow particle size distribution range and uniform particle size distribution. Specific Embodiments

[0037] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0038] Example 1

[0039] This example provides a preparation method for a high-nickel ternary precursor based on spray pyrolysis, and the preparation method includes the following steps:

[0040] (1) Prepare a mixed salt solution by mixing nickel sulfate, cobalt sulfate, manganese sulfate and water in a molar ratio of nickel ions, cobalt ions and manganese ions of 0.75:0.05:0.20. Then add zirconium sulfate and perfluoropolyether surfactant (Krytox143) to obtain a high-nickel ternary solution with a concentration of 155 g / L. Among them, the concentration of zirconium ions in the high-nickel ternary solution is 0.1 mol%, and the content of perfluoropolyether surfactant is 0.3 wt%.

[0041] (2) Set the pressure of the two-fluid spray gun to 0.25 MPa, introduce supercritical CO2, and atomize the high-nickel ternary solution described in step (1) at a temperature of 35 °C. Among them, the volume ratio of supercritical CO2 to the high-nickel ternary solution is 3:1. Then pyrolyze at a temperature of 600 °C in the calcination furnace for 5 s to obtain the high-nickel ternary precursor based on spray pyrolysis.

[0042] Example 2

[0043] This example provides a method for preparing a high-nickel ternary precursor based on spray pyrolysis. The preparation method includes the following steps:

[0044] (1) Prepare a mixed salt solution by mixing nickel sulfate, cobalt sulfate, manganese sulfate and water in a molar ratio of nickel ions, cobalt ions and manganese ions of 0.70:0.10:0.20. Then add zirconium sulfate and perfluoropolyether surfactant (Krytox143) to obtain a high-nickel ternary solution with a concentration of 150 g / L. Among them, the concentration of zirconium ions in the high-nickel ternary solution is 0.2 mol%, and the content of perfluoropolyether surfactant is 0.1 wt%.

[0045] (2) Set the pressure of the two-fluid spray gun to 0.1 MPa, introduce supercritical CO2, and atomize the high-nickel ternary solution described in step (1) at a temperature of 40 °C. Among them, the volume ratio of supercritical CO2 to the high-nickel ternary solution is 4:1. Then pyrolyze at a temperature of 700 °C in the calcination furnace for 5 s to obtain the high-nickel ternary precursor based on spray pyrolysis.

[0046] Example 3

[0047] This example provides a method for preparing a high-nickel ternary precursor based on spray pyrolysis. The preparation method includes the following steps:

[0048] (1) Prepare a mixed salt solution by mixing nickel sulfate, cobalt sulfate, manganese sulfate and water in a molar ratio of nickel ions, cobalt ions and manganese ions of 0.70:0.05:0.25. Then add zirconium sulfate and a perfluoropolyether surfactant (Krytox143) to obtain a high-nickel ternary solution with a concentration of 160 g / L. Among them, the concentration of zirconium ions in the high-nickel ternary solution is 0.1 mol%, and the content of the perfluoropolyether surfactant is 0.5 wt%.

[0049] (2) Set the pressure of the two-fluid spray gun to 0.5 MPa, introduce supercritical CO2, and atomize the high-nickel ternary solution described in step (1) at a temperature of 35°C. Among them, the volume ratio of supercritical CO2 to the high-nickel ternary solution is 2.5:1. Then pyrolyze at a temperature of 500°C in the calcination furnace for 10 s to obtain the high-nickel ternary precursor based on the spray pyrolysis method.

[0050] Example 4

[0051] This example provides a preparation method of a high-nickel ternary precursor based on the spray pyrolysis method. Except that the pressure of the two-fluid spray gun is set to 0.07 MPa in step (2), the rest are the same as in Example 1.

[0052] Example 5

[0053] This example provides a preparation method of a high-nickel ternary precursor based on the spray pyrolysis method. Except that the pressure of the two-fluid spray gun is set to 0.8 MPa in step (2), the rest are the same as in Example 1.

[0054] Example 6

[0055] This example provides a preparation method of a high-nickel ternary precursor based on the spray pyrolysis method. Except that the content of the perfluoropolyether surfactant is 0.07 wt% in step (1), the rest are the same as in Example 1.

[0056] Example 7

[0057] This example provides a preparation method of a high-nickel ternary precursor based on the spray pyrolysis method. Except that the content of the perfluoropolyether surfactant is 0.8 wt% in step (1), the rest are the same as in Example 1.

[0058] Example 8

[0059] This example provides a preparation method of a high-nickel ternary precursor based on the spray pyrolysis method. Except that the perfluoropolyether surfactant is replaced with sodium dodecyl sulfate in equal mass in step (1), the rest are the same as in Example 1.

[0060] Comparative Example 1

[0061] This comparative example provides a method for preparing a high-nickel ternary precursor based on spray pyrolysis. Except that the supercritical CO2 in step (2) is replaced with air in equal volume and air atomization of the high-nickel ternary liquid is used, the rest is the same as in Example 1.

[0062] Comparative Example 2

[0063] This comparative example provides a method for preparing a high-nickel ternary precursor based on spray pyrolysis. Except that no surfactant is added in step (1), the rest is the same as in Example 1.

[0064] The particle size D50 and the particle size distribution width Span of the high-nickel ternary precursors obtained in the above examples and comparative examples are shown in Table 1:

[0065] Table 1

[0066] Particle size D50 (μm) Particle size distribution width Span Example 1 2.0 0.8 Example 2 6.0 2.0 Example 3 3.0 1.5 Example 4 5.0 2.5 Example 5 0.5 0.7 Example 6 7.0 2.5 Example 7 0.5 0.7 Example 8 3.0 2.5 Comparative Example 1 12.0 3.0 Comparative Example 2 20.0 4.0

[0067] It can be seen from Table 1 that:

[0068] From Example 1 and Comparative Examples 1-2, it can be seen that by using supercritical CO2 instead of air as the atomization gas and adding a surfactant in the present invention, a high-nickel ternary precursor with a narrow particle size distribution range and a suitable particle size D50 is obtained; from Example 1 and Examples 4-5, it can be seen that the pressure during atomization in the present invention will affect the size of the generated droplets, thereby affecting the particle size distribution and the particle size D50 of the product; from Example 1 and Examples 6-7, it can be seen that the addition amount of the surfactant in the present invention will also affect the particle size distribution and the particle size D50 of the product; from Example 1 and Example 8, it can be seen that the present invention preferably uses perfluoropolyether surfactants, which have a higher matching degree with supercritical CO2 and can further improve the uniformity of the particle size distribution of the product.

[0069] The above is only the specific implementation manner 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 thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of a high-nickel ternary precursor based on spray pyrolysis, characterized in that, The preparation method comprises the following steps: Perform spray pyrolysis on the high-nickel ternary solution. Among them, supercritical CO2 is used to atomize the high-nickel ternary solution to obtain the high-nickel ternary precursor based on the spray pyrolysis method; The high-nickel ternary solution includes a surfactant.

2. The preparation method according to claim 1, characterized in that, The pressure for atomizing the high-nickel ternary solution with supercritical CO2 is 0.1 MPa - 0.5 MPa; Preferably, in a two-fluid spray gun, supercritical CO2 is used to atomize the high-nickel ternary solution.

3. The preparation method according to claim 1 or 2, characterized in that, The surfactant includes a perfluoropolyether surfactant; Preferably, in the high-nickel ternary solution, the content of the surfactant is 0.1 wt% - 0.5 wt%.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The high-nickel ternary solution is doped with zirconium ions; Preferably, in the high-nickel ternary solution, the concentration of zirconium ions is 0.1 mol% - 0.2 mol%; Preferably, the volume ratio of the supercritical CO2 to the high-nickel ternary solution is (2.5 - 4):1; Preferably, the temperature for atomizing the high-nickel ternary solution with supercritical CO2 is 35°C - 40°C.

5. The preparation method according to any one of claims 1-4, characterized in that, The concentration of the high-nickel ternary solution is 150 g / L - 160 g / L; Preferably, in the high-nickel ternary solution, the molar ratio of nickel ions, cobalt ions, and manganese ions is (0.65 - 0.85):(0.03 - 0.1):(0.12 - 0.32).

6. The preparation method according to any one of claims 1-5, characterized in that, The temperature of the spray pyrolysis is 500°C - 700°C; Preferably, the time of the spray pyrolysis is 5 s - 10 s.

7. A high-nickel ternary precursor based on spray pyrolysis method, characterized in that, The high-nickel ternary precursor based on the spray pyrolysis method is prepared by using the preparation method described in any one of claims 1 - 6.

8. The high-nickel ternary precursor based on spray pyrolysis according to claim 7, characterized in that, The particle size D50 of the high-nickel ternary precursor based on the spray pyrolysis method is 0.5 μm - 6 μm; Preferably, the particle size distribution width Span of the high-nickel ternary precursor based on the spray pyrolysis method is 0.7 - 2.

0.

9. A high-nickel cathode material, characterized in that, The raw materials for preparing the high-nickel cathode material include the high-nickel ternary precursor based on the spray pyrolysis method described in claim 7 or 8.

10. A lithium-ion battery, characterized in that, The lithium-ion battery includes the high-nickel cathode material described in claim 9.