Nickel-cobalt-aluminum ternary positive electrode material and preparation method and application thereof

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a nickel-cobalt-aluminum ternary positive electrode material and a preparation method and application thereof. The preparation method of the nickel-cobalt-aluminum ternary positive electrode material provided by the invention comprises the following steps: 1) dissolving a dispersing agent in a solvent to form a dispersing agent solution, then mixing fluoride, phosphate and the dispersing agent-containing solution, and performing dispersion treatment to obtain a coating solution; 2) mixing and stirring a nickel-cobalt-aluminum ternary precursor and the coating solution in the step 1), and then heating and stirring to obtain a solid coating; and 3) calcining the solid coating obtained in the step 2) under the protection of an inactive gas to obtain the nickel-cobalt-aluminum ternary positive electrode material. The nickel-cobalt-aluminum ternary positive electrode material prepared by the preparation method has high first discharge specific capacity, high first efficiency and high capacity retention rate.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a nickel-cobalt-aluminum ternary cathode material, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and energy storage systems due to their advantages such as high energy density, long cycle life, and no memory effect. Nickel-cobalt-aluminum (NCA) ternary cathode materials have become a research and application hotspot due to their high theoretical specific capacity (approximately 274 mAh / g), good cycle performance, and high operating voltage platform. However, NCA cathode materials face several challenges in practical applications. During charge and discharge, structural changes and side reactions with the electrolyte lead to rapid capacity decay, especially at high temperatures. This is because the active sites on the NCA material surface readily react with impurities in the electrolyte (such as HF), generating harmful products that damage the material's structural integrity and reduce specific capacity and cycle stability. Simultaneously, NCA materials exhibit low initial charge-discharge efficiency and irreversible capacity loss, affecting the overall energy utilization efficiency of the battery.

[0003] Currently, common methods for addressing these issues include elemental doping, surface coating, and optimized synthesis processes. Surface coating can form a protective film on the surface of NCA materials, reducing side reactions and improving specific capacity and cycling performance. However, existing coating materials for modified NCA materials have limitations in improving performance; their specific capacity, first-efficiency, and cycle capacity retention still need to be improved. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of existing coated and modified NCA materials, which still have room for improvement in specific capacity, first efficiency and cycle capacity retention, thereby providing a nickel-cobalt-aluminum ternary cathode material, its preparation method and application.

[0005] This invention provides a method for preparing a nickel-cobalt-aluminum ternary cathode material, comprising the following steps:

[0006] 1) Dissolve the dispersant in a solvent to form a dispersant solution, then mix and disperse the fluoride, phosphate and dispersant solution to obtain a coating solution;

[0007] 2) Mix the nickel-cobalt-aluminum ternary precursor with the coating solution in step 1), stir, and then heat and stir to obtain a solid coating;

[0008] 3) The solid coating obtained in step 2) is calcined under the protection of an inert gas to obtain the nickel-cobalt-aluminum ternary cathode material.

[0009] Preferably, the dispersant in step 1) is selected from at least one of polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG);

[0010] The solvent is selected from at least one of deionized water, ethanol, and N-methylpyrrolidone (NMP);

[0011] The fluoride is selected from at least one of lithium fluoride and magnesium fluoride;

[0012] The phosphate is selected from at least one of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and lithium phosphate.

[0013] Preferably, the molar ratio of fluoride to phosphate in step 1) is (1-2):(1-3);

[0014] The dispersant accounts for 1-5% of the total mass of fluoride and phosphate;

[0015] The mass concentration of the dispersant in the dispersant solution is 2-5%.

[0016] Preferably, step 1) of mixing the fluoride, phosphate and the solution containing the dispersant further includes the step of adding borate;

[0017] Preferably, the molar ratio of the borate to the fluoride is (1-5):1;

[0018] The borate is selected from at least one of sodium borate, ammonium borate, calcium borate, and lithium borate.

[0019] Preferably, the dispersion treatment in step 1) includes at least one dispersion method selected from ultrasonic dispersion and ball milling dispersion;

[0020] Optionally, the ultrasonic power of the ultrasonic dispersion is 300-500W, and the ultrasonic time is 10-30min;

[0021] Optionally, the ball milling speed for ball milling dispersion is 300-500 rpm, the ball milling time is 1-3 h, and the ball-to-material ratio is (5-10):1.

[0022] Preferably, the general chemical formula of the nickel-cobalt-aluminum ternary precursor in step 2) is: Ni x Co y Al z (OH)2, where 0.88≤x≤0.95, 0.05≤y≤0.12, 0≤z≤0.05, x+y+z=1;

[0023] The average particle size of the nickel-cobalt-aluminum ternary precursor is 5-10 μm;

[0024] The mass ratio of the nickel-cobalt-aluminum ternary precursor to the total mass of fluoride and phosphate is 100:(1-5);

[0025] The mixing temperature in step 2) is 5-40℃, the mixing speed is 300-500 rpm, and the mixing time is 0.5-2h;

[0026] Optionally, the mixing temperature is room temperature. Optionally, the mixing temperature is 25°C.

[0027] The heating and stirring temperature in step 2) is 60-100℃, and the heating and stirring speed is 300-500rpm.

[0028] Preferably, the inert gas in step 3) includes at least one of an inert gas and nitrogen.

[0029] Preferably, the inert gas includes at least one of argon and nitrogen;

[0030] The calcination temperature in step 3) is 600-900℃, and the calcination time is 2-6h.

[0031] Optionally, the heating rate of the calcination is 2-5℃ / min;

[0032] Optionally, the calcination step may further include a cooling step after the calcination step is completed.

[0033] This invention provides a nickel-cobalt-aluminum ternary cathode material, which is prepared by the above-described method for preparing nickel-cobalt-aluminum ternary cathode materials.

[0034] The present invention also provides an application of the above-described nickel-cobalt-aluminum ternary cathode material in lithium-ion batteries.

[0035] The technical solution of this invention has the following advantages:

[0036] 1. The preparation method of the nickel-cobalt-aluminum ternary cathode material provided by the present invention includes the following steps: 1) dissolving a dispersant in a solvent to form a dispersant solution, then mixing and dispersing the fluoride, phosphate, and the dispersant solution to obtain a coating solution; 2) mixing and stirring the nickel-cobalt-aluminum ternary precursor with the coating solution in step 1), then heating and stirring to obtain a solid coating; 3) calcining the solid coating obtained in step 2) under the protection of an inert gas to obtain the nickel-cobalt-aluminum ternary cathode material. The present invention disperses and coats the fluoride and phosphate in the nickel-cobalt-aluminum ternary precursor with a dispersant solution, not only uniformly coating the fluoride and phosphate, but also achieving final surface coating of the fluoride and phosphate in the nickel-cobalt-aluminum ternary cathode material. - With surface and shallow O 2-Strong bonds are formed, inhibiting the formation of the rock salt phase (NiO) under high voltage and delaying structural collapse. Fluorides are chemically stable and can form a robust barrier on the surface and shallow layer of the cathode material. During charge and discharge, the material structure is susceptible to lithium-ion insertion / extraction, and this barrier prevents excessive structural deformation. Simultaneously, phosphates interact with the lattice of the shallow cathode material, enhancing lattice stability. During high-temperature calcination, phosphates react with surface defects, filling oxygen vacancies. The co-coating of fluorides and phosphates on the surface and shallow layer of the cathode material synergistically reduces capacity decay caused by structural changes, extending battery life. Calcination in an inert gas prevents material oxidation at high temperatures, maintains the chemical stability of the coating layer, and avoids the potential decomposition of fluorides / phosphates due to oxygen. Through a unique fluoride / phosphate composite coating system, the electronic structure and ion transport channels of the material are optimized, greatly activating active sites and improving the initial discharge specific capacity and initial efficiency, far exceeding uncoated materials and traditional coated materials, providing a more powerful energy output for the battery. The innovative coating design effectively isolates electrolyte impurities from damaging the material structure, greatly reducing structural changes and capacity decay during cycling. The nickel-cobalt-aluminum ternary cathode material prepared by the method of this invention exhibits high initial discharge specific capacity, high initial efficiency, and high capacity retention.

[0037] 2. The preparation method of the nickel-cobalt-aluminum ternary cathode material provided by the present invention, wherein the dispersant in step 1) is selected from at least one of polyvinylpyrrolidone and polyethylene glycol; the solvent is selected from at least one of deionized water, ethanol, and N-methylpyrrolidone; the fluoride is selected from at least one of lithium fluoride and magnesium fluoride; and the phosphate is selected from at least one of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and lithium phosphate. By selecting specific dispersants, the present invention can coordinate with fluorine / phosphate through the -OH / -C=O groups in the dispersant, forming a more uniform nano-coating layer on the surface of the nickel-cobalt-aluminum ternary cathode material. The fluoride and phosphate in the shallow layer are more evenly distributed, further improving the initial discharge specific capacity, initial efficiency, and capacity retention of the obtained nickel-cobalt-aluminum ternary cathode material.

[0038] 3. The preparation method of the nickel-cobalt-aluminum ternary cathode material provided by the present invention, in step 1), the step of mixing fluoride, phosphate and a solution containing a dispersant, further includes the step of adding borate; the present invention simultaneously coats fluoride, phosphate and borate by wet process, and the three synergistically enhance the interfacial stability: F - With surface O 2- Strong bonds are formed, inhibiting the formation of rock salt phase (NiO) under high voltage (>4.3V), delaying structural collapse. During high-temperature calcination, phosphate reacts with surface defects to fill oxygen vacancies. 3+ With F - [BF4] is formed. -The coordination structure enhances the bonding force between LiF, Li3PO4 and the interface, further improving the initial discharge specific capacity, initial efficiency and capacity retention of the prepared nickel-cobalt-aluminum ternary cathode material. Detailed Implementation

[0039] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0040] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0041] The nickel-cobalt-aluminum ternary precursor of the present invention can be conventionally prepared by those skilled in the art via hydroxide co-precipitation, wherein Ni 0.9 Co 0.08 Al 0.02 The preparation method of (OH)2 includes: mixing 0.90 mol nickel sulfate, 0.08 mol cobalt sulfate, 0.01 mol aluminum sulfate, and deionized water to form a mixed solution, which is then placed in a reaction vessel. The total molar concentration of nickel sulfate, cobalt sulfate, and aluminum sulfate in the mixed solution is 4 mol / L. Then, 4 mol / L NaOH solution and 8 mol / L ammonia solution are added to control the pH of the reaction solution to 11.8 and the mass concentration of ammonia in the reaction solution to 8 g / L. The co-precipitation reaction is carried out at 70℃ and 600 rpm with continuous stirring for 50 h. After solid-liquid separation, the collected solid is washed and dried to obtain the nickel-cobalt-aluminum ternary precursor, Ni. 0.9 Co 0.07 Al 0.03 The preparation method of (OH)2 includes: mixing 0.90 mol nickel sulfate, 0.07 mol cobalt sulfate, 0.015 mol aluminum sulfate and deionized water to form a mixed solution and placing it in a reaction vessel. The total molar concentration of nickel sulfate, cobalt sulfate and aluminum sulfate in the mixed solution is 4 mol / L. Then, 4 mol / L NaOH solution and 8 mol / L ammonia solution are added to control the pH of the reaction solution to 11.8 and the mass concentration of ammonia in the reaction solution to 8 g / L. The co-precipitation reaction is carried out at 70℃ and 600 rpm for 50 h with continuous stirring. After solid-liquid separation, the collected solid is washed and dried to obtain the nickel-cobalt-aluminum ternary precursor.

[0042] Example 1

[0043] This embodiment provides a method for preparing a nickel-cobalt-aluminum ternary cathode material, including the following steps:

[0044] 1) PVP was dissolved in ethanol to form a dispersant solution with a PVP mass concentration of 3%. Then, LiF and NH4H2PO4 were added to the dispersant solution at a molar ratio of 1:1 and stirred until homogeneous. The mixture was then ultrasonically dispersed at 400W for 20 minutes to ensure that LiF and NH4H2PO4 were uniformly dispersed in the solution, thus obtaining a coated solution. The mass of PVP accounted for 3% of the total mass of LiF and NH4H2PO4.

[0045] 2) Ni, a nickel-cobalt-aluminum ternary precursor with an average particle size of 10 μm 0.9 Co 0.8 Al 0.2 (OH)₂ and the coating solution from step 1) were mixed and stirred at 25°C and 400 rpm for 1 hour, and then heated and stirred at 80°C and 400 rpm to evaporate the solvent until a solid coating was obtained; wherein the nickel-cobalt-aluminum ternary precursor Ni 0.9 Co 0.8 Al 0.2 The mass ratio of (OH)2 to the total mass of LiF and NH4H2PO4 in the coating solution in step 1) is 100:2;

[0046] 3) The solid coating obtained in step 2) is transferred to a high-temperature furnace and calcined under argon protection. The calcination heating rate is 3℃ / min, the calcination temperature is 700℃, and the calcination time is 4h. After calcination, the material is cooled to room temperature with the furnace to obtain the nickel-cobalt-aluminum ternary cathode material.

[0047] Example 2

[0048] This embodiment provides a method for preparing a nickel-cobalt-aluminum ternary cathode material, including the following steps:

[0049] 1) Dissolve PEG in deionized water to form a dispersant solution with a PEG mass concentration of 2%. Then, add MgF2 and (NH4)2HPO4 to the dispersant solution at a molar ratio of 2:1 and stir until homogeneous. Disperse the mixture using ball milling at 500 rpm for 2 hours with a ball-to-material ratio of 8:1 to ensure uniform dispersion of MgF2 and (NH4)2HPO4 in the solution, thus obtaining a coated solution. The mass of PEG accounts for 2% of the total mass of MgF2 and (NH4)2HPO4.

[0050] 2) Ni cobalt aluminum ternary precursor with an average particle size of 6 μm 0.9 Co 0.7 Al 0.3(OH)₂ and the coating solution from step 1) were mixed and stirred at 25°C and 500 rpm for 1 hour, and then heated and stirred at 80°C and 500 rpm to evaporate the solvent until a solid coating was obtained; wherein the nickel-cobalt-aluminum ternary precursor Ni 0.9 Co 0.7 Al 0.3 The mass ratio of (OH)2 to the total mass of MgF2 and (NH4)2HPO4 in the coating solution in step 1) is 100:3;

[0051] 3) The solid coating obtained in step 2) is transferred to a high-temperature furnace and calcined under argon protection. The calcination heating rate is 4℃ / min, the calcination temperature is 800℃, and the calcination time is 5h. After calcination, the material is cooled to room temperature in the furnace to obtain the nickel-cobalt-aluminum ternary cathode material.

[0052] Example 3

[0053] This embodiment provides a method for preparing a nickel-cobalt-aluminum ternary cathode material, including the following steps:

[0054] 1) Dissolve PVP in ethanol to form a dispersant solution with a PVP mass concentration of 5%. Then, add LiF and NH4H2PO4 to the dispersant solution at a molar ratio of 1:2 and stir until homogeneous. Then, use 500W ultrasonic dispersion for 30 minutes to ensure that LiF and NH4H2PO4 are uniformly dispersed in the solution, thus obtaining a coated solution. The mass of PVP accounts for 5% of the total mass of LiF and NH4H2PO4.

[0055] 2) Ni, a nickel-cobalt-aluminum ternary precursor with an average particle size of 7 μm. 0.9 Co 0.8 Al 0.2 (OH)₂ and the coating solution from step 1) were mixed and stirred at 25°C and 500 rpm for 0.5 h, and then heated and stirred at 100°C and 500 rpm to evaporate the solvent until a solid coating was obtained; wherein the nickel-cobalt-aluminum ternary precursor Ni 0.9 Co 0.8 Al 0.2 The mass ratio of (OH)2 to the total mass of LiF and NH4H2PO4 in the coating solution in step 1) is 100:5;

[0056] 3) The solid coating obtained in step 2) is transferred to a high-temperature furnace and calcined under argon protection. The calcination heating rate is 5℃ / min, the calcination temperature is 600℃, and the calcination time is 6h. After calcination, the material is cooled to room temperature in the furnace to obtain the nickel-cobalt-aluminum ternary cathode material.

[0057] Example 4

[0058] This embodiment provides a method for preparing a nickel-cobalt-aluminum ternary cathode material, including the following steps:

[0059] 1) PVP was dissolved in ethanol to form a dispersant solution with a PVP mass concentration of 3%. Then, LiF and NH4H2PO4 were added to the dispersant solution at a molar ratio of 1:3 and stirred until homogeneous. The mixture was then ultrasonically dispersed at 500W for 10 minutes to ensure that LiF and NH4H2PO4 were uniformly dispersed in the solution, thus obtaining a coated solution. The mass of PVP accounted for 2% of the total mass of LiF and NH4H2PO4.

[0060] 2) Ni, a nickel-cobalt-aluminum ternary precursor with an average particle size of 5 μm. 0.9 Co 0.8 Al 0.2 (OH)₂ and the coating solution from step 1) were mixed and stirred at 25°C and 300 rpm for 2 hours, and then heated and stirred at 60°C and 300 rpm to evaporate the solvent until a solid coating was obtained; wherein the nickel-cobalt-aluminum ternary precursor Ni 0.9 Co 0.8 Al 0.2 The mass ratio of (OH)2 to the total mass of LiF and NH4H2PO4 in the coating solution in step 1) is 100:1;

[0061] 3) The solid coating obtained in step 2) is transferred to a high-temperature furnace and calcined under argon protection. The calcination heating rate is 2℃ / min, the calcination temperature is 900℃, and the calcination time is 2h. After calcination, the material is cooled to room temperature in the furnace to obtain the nickel-cobalt-aluminum ternary cathode material.

[0062] Example 5

[0063] This embodiment provides a method for preparing a nickel-cobalt-aluminum ternary cathode material, including the following steps:

[0064] 1) PVP was dissolved in ethanol to form a dispersant solution with a PVP mass concentration of 3%. Then, LiF, NH4H2PO4, and Li3BO3 were added to the dispersant solution in a molar ratio of 1:1:2 and stirred until homogeneous. The mixture was then ultrasonically dispersed at 400W for 20 minutes to ensure that LiF and NH4H2PO4 were uniformly dispersed in the solution, thus obtaining a coated solution. The mass of PVP accounted for 3% of the total mass of LiF and NH4H2PO4.

[0065] 2) Ni, a nickel-cobalt-aluminum ternary precursor with an average particle size of 10 μm 0.9 Co 0.8 Al 0.2(OH)₂ and the coating solution from step 1) were mixed and stirred at 25°C and 400 rpm for 1 hour, and then heated and stirred at 80°C and 400 rpm to evaporate the solvent until a solid coating was obtained; wherein the nickel-cobalt-aluminum ternary precursor Ni 0.9 Co 0.8 Al 0.2 The mass ratio of (OH)2 to the total mass of LiF and NH4H2PO4 in the coating solution in step 1) is 100:2;

[0066] 3) The solid coating obtained in step 2) is transferred to a high-temperature furnace and calcined under argon protection. The calcination heating rate is 3℃ / min, the calcination temperature is 700℃, and the calcination time is 4h. After calcination, the material is cooled to room temperature with the furnace to obtain the nickel-cobalt-aluminum ternary cathode material.

[0067] Comparative Example 1

[0068] This comparative example provides a method for preparing a nickel-cobalt-aluminum ternary cathode material, including the following steps:

[0069] The nickel-cobalt-aluminum ternary precursor with an average particle size of 10 μm, Ni 0.9 Co 0.8 Al 0.2 (OH)2 is transferred to a high-temperature furnace and calcined under argon protection. The calcination heating rate is 3℃ / min, the calcination temperature is 700℃, and the calcination time is 4h. After calcination, the furnace is cooled to room temperature to obtain the nickel-cobalt-aluminum ternary cathode material.

[0070] Comparative Example 2

[0071] This comparative example provides a method for preparing a nickel-cobalt-aluminum ternary cathode material, including the following steps:

[0072] 1) Ni cobalt aluminum ternary precursor with an average particle size of 10 μm 0.9 Co 0.8 Al 0.2 (OH)₂ was mixed with LiF and NH₄H₂PO₄ and ground at 25℃ and 500 rpm for 2 hours with a ball-to-material ratio of 8:1 to obtain a solid coating; wherein the nickel-cobalt-aluminum ternary precursor Ni 0.9 Co 0.8 Al 0.2 The mass ratio of (OH)2 to the total mass of LiF and NH4H2PO4 is 100:2;

[0073] 2) The solid coating obtained in step 1) is transferred to a high-temperature furnace and calcined under argon protection. The calcination heating rate is 3℃ / min, the calcination temperature is 700℃, and the calcination time is 4h. After calcination, the material is cooled to room temperature with the furnace to obtain the nickel-cobalt-aluminum ternary cathode material.

[0074] Comparative Example 3

[0075] This comparative example provides a nickel-cobalt-aluminum ternary cathode material, which differs from Example 1 in that NH4H2PO4 is replaced with NH4HSO4 in step 1).

[0076] Comparative Example 4

[0077] This comparative example provides a nickel-cobalt-aluminum ternary cathode material, which differs from Example 1 in that in step 1), LiF is replaced with LiCl in equimolar amounts.

[0078] Comparative Example 5

[0079] This comparative example provides a nickel-cobalt-aluminum ternary cathode material, which differs from Example 1 in that it undergoes calcination under oxygen protection in step 3).

[0080] Test case

[0081] The nickel-cobalt-aluminum ternary cathode materials obtained in Examples 1-5 and Comparative Examples 1-5 were used as the main materials to prepare coin cells for electrical performance testing. Coin cell preparation: A mixture of 90 (main material): 5 (polyvinylidene fluoride PVDF): 5 (acetylene black) in N-methylpyrrolidone solvent was homogenized, coated, dried, and cut to form the cathode sheet (the areal density of the cathode material was 7.5 mg / cm³). 2 A CR2032 coin cell was assembled in an argon-filled glove box using a lithium metal sheet as the counter electrode, a glass fiber as the separator, and a 1 mol / L lithium hexafluorophosphate solution of ethylene carbonate (EC) and dimethyl carbonate (DMC) (EC to DMC volume ratio of 1:1) as the electrolyte.

[0082] The prepared coin cells were placed in the Blue Electric testing system for electrical performance testing. The testing conditions were: charge / discharge voltage range of 2.5V-4.25V, test temperature of 25℃, and one cycle at 0.1C / 0.1C to test the initial charge specific capacity and initial discharge specific capacity. The initial efficiency was calculated as (initial discharge specific capacity / initial charge specific capacity * 100%). Then, the cells were cycled at 1C / 1C for 50 cycles to test their cycle performance (capacity retention rate as (discharge specific capacity at cycle 51 / discharge specific capacity at cycle 2 * 100%). The test results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a nickel-cobalt-aluminum ternary cathode material, characterized in that, Includes the following steps: 1) Dissolve the dispersant in a solvent to form a dispersant solution, then mix and disperse the fluoride, phosphate and dispersant solution to obtain a coating solution; 2) Mix the nickel-cobalt-aluminum ternary precursor with the coating solution in step 1), stir, and then heat and stir to obtain a solid coating; 3) The solid coating obtained in step 2) is calcined under the protection of an inert gas to obtain the nickel-cobalt-aluminum ternary cathode material.

2. The method for preparing the nickel-cobalt-aluminum ternary cathode material according to claim 1, characterized in that, The dispersant mentioned in step 1) is selected from at least one of polyvinylpyrrolidone and polyethylene glycol; The solvent is selected from at least one of deionized water, ethanol, and N-methylpyrrolidone; The fluoride is selected from at least one of lithium fluoride and magnesium fluoride; The phosphate is selected from at least one of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and lithium phosphate.

3. The method for preparing the nickel-cobalt-aluminum ternary cathode material according to claim 1 or 2, characterized in that, The molar ratio of fluoride to phosphate in step 1) is (1-2):(1-3); The dispersant accounts for 1-5% of the total mass of fluoride and phosphate; The mass concentration of the dispersant in the dispersant solution is 2-5%.

4. The method for preparing the nickel-cobalt-aluminum ternary cathode material according to any one of claims 1-3, characterized in that, Step 1), which involves mixing the fluoride, phosphate, and solution containing the dispersant, also includes the addition of borates.

5. The method for preparing the nickel-cobalt-aluminum ternary cathode material according to claim 4, characterized in that, The molar ratio of the borate to the fluoride is (1-5):1; The borate is selected from at least one of sodium borate, ammonium borate, calcium borate, and lithium borate.

6. The method for preparing the nickel-cobalt-aluminum ternary cathode material according to any one of claims 1-5, characterized in that, The dispersion treatment described in step 1) includes at least one dispersion method selected from ultrasonic dispersion and ball milling dispersion; Optionally, the ultrasonic power of the ultrasonic dispersion is 300-500W, and the ultrasonic time is 10-30min; Optionally, the ball milling speed for ball milling dispersion is 300-500 rpm, the ball milling time is 1-3 h, and the ball-to-material ratio is (5-10):

1.

7. The method for preparing the nickel-cobalt-aluminum ternary cathode material according to any one of claims 1-6, characterized in that, The general chemical formula of the nickel-cobalt-aluminum ternary precursor mentioned in step 2) is: Ni x Co y Al z (OH)2, where 0.88≤x≤0.95, 0.05≤y≤0.12, 0≤z≤0.05, x+y+z=1; The average particle size of the nickel-cobalt-aluminum ternary precursor is 5-10 μm; The mass ratio of the nickel-cobalt-aluminum ternary precursor to the total mass of fluoride and phosphate is 100:(1-5); The mixing temperature in step 2) is 5-40℃, the mixing speed is 300-500 rpm, and the mixing time is 0.5-2h; The heating and stirring temperature in step 2) is 60-100℃, and the heating and stirring speed is 300-500rpm.

8. The method for preparing the nickel-cobalt-aluminum ternary cathode material according to any one of claims 1-7, characterized in that, The inert gas mentioned in step 3) includes at least one of inert gases and nitrogen; Preferably, the inert gas includes at least one of argon and nitrogen; The calcination temperature in step 3) is 600-900℃, and the calcination time is 2-6h; Optionally, the heating rate of the calcination is 2-5℃ / min; Optionally, the calcination step may further include a cooling step after the calcination step is completed.

9. A nickel-cobalt-aluminum ternary cathode material, characterized in that, It is prepared by the method for preparing nickel-cobalt-aluminum ternary cathode material according to any one of claims 1-8.

10. The application of the nickel-cobalt-aluminum ternary cathode material according to claim 9 in lithium-ion batteries.

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