Carbonate precursor, high-nickel single-crystal positive electrode material and preparation method thereof

Abstract

The application discloses a carbonate precursor, a high-nickel single-crystal positive electrode material and a preparation method thereof, and relates to the technical field of lithium ion battery positive electrode materials. The preparation method of the high-nickel single-crystal positive electrode material comprises the following steps: mixing a carbonate precursor with lithium hydroxide and strontium carbonate after sintering; sintering the mixed material under a pure oxygen atmosphere, and naturally cooling after sintering; performing airflow crushing to obtain an intermediate product; uniformly mixing the intermediate product with cobalt hydroxide, titanium dioxide and lithium hydroxide; sintering under a pure oxygen atmosphere, and naturally cooling after sintering. The high-nickel single-crystal positive electrode material is obtained. Beneficial effects: the high specific surface area precursor is prepared by a urea pyrolysis method, and then the high-porosity precursor is obtained after pre-sintering, so that the high-temperature sintering temperature of the high-nickel single-crystal ternary material can be obviously reduced, the disproportionation reaction of trivalent nickel can be effectively reduced, and the prepared high-nickel single-crystal positive electrode material has the characteristics of large primary particles, smooth surface and high specific capacity.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery cathode material technology, and specifically discloses a carbonate precursor, a high-nickel single-crystal cathode material and its preparation method. Background Technology

[0002] In recent years, with the rapid development of the new energy vehicle industry, the demand for lithium-ion batteries has grown rapidly. People have increasingly higher requirements for the driving range of new energy vehicles and have put forward higher requirements for safety performance. The demand for high-energy-density and high-safety lithium-ion batteries has grown rapidly. Due to the low energy density of lithium iron phosphate and the poor safety performance of high-nickel polycrystalline materials due to their small primary particles, neither can simultaneously meet the two indicators of high energy density and high safety. However, high-nickel single-crystal cathode materials, due to their high nickel content and high specific capacity, as well as their large primary particles and good thermal stability, can simultaneously meet the two indicators of high energy density and high safety. High-nickel single-crystal cathode materials have the characteristics of high capacity and high safety, but they also have certain drawbacks. Due to the high nickel content and large primary particles, the required sintering temperature is too high. Furthermore, trivalent nickel has poor stability at high temperatures and is prone to disproportionation into divalent and tetravalent nickel, resulting in a decrease in the specific capacity of the material.

[0003] Currently, the main preparation process for high-nickel single-crystal cathode materials is a two-stage sintering process. The specific process is as follows: after the precursor, lithium hydroxide, and additives are mixed evenly, they are sintered at high temperature in a kiln. Then, after crushing, the surface is coated and sintered a second time. The precursor used is basically a hydroxide prepared by co-precipitation. This precursor has the characteristics of high tap density, but it also has the disadvantages of poor reactivity and difficulty in growth when mixed with lithium salt for sintering.

[0004] Chinese patent application CN115028210A discloses a method for preparing a single-crystal high-nickel cathode material, belonging to the field of lithium-ion batteries. The method involves first preparing a single-crystal doped nickel hydroxide precursor with relatively large primary particles using an ammonia complexation-boiling precipitation method. The precursor is then mixed with a lithium source and calcined under an oxygen atmosphere to obtain a single-crystal cathode material with primary particles of 1–5 μm. This patent overcomes the harsh conditions of high temperature and high lithium superphosphate ratio, as well as the complex processes such as water washing, involved in the traditional preparation of single-crystal cathode materials. It has advantages such as a shorter process, energy saving and consumption reduction, and wide applicability. The prepared material exhibits advantages such as high specific capacity, high compaction density, good cycle performance, and good rate performance. However, this patent does not address reducing the sintering temperature, improving the particle size, surface smoothness, or specific capacity of the material. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to prepare needle-shaped carbonate precursors with high specific surface area, and how to reduce the high-temperature sintering temperature and prepare high-nickel single-crystal cathode materials with large primary particles, smooth surfaces, and high specific capacity.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] The first aspect of this invention provides a carbonate precursor having the chemical formula Ni x Co y Mn z CO3, where 0.60≤x≤0.88, 0.03≤y≤0.15, 0.06≤z≤0.35, x+y+z=1.00; the particle size D50 of this carbonate precursor is 2-6μm.

[0008] Beneficial effects: This invention uses urea pyrolysis to prepare carbonate precursors. It utilizes the carbon dioxide generated by urea pyrolysis to react with nickel, cobalt, and manganese metal ions to prepare nickel, cobalt, and manganese carbonates. By controlling the urea decomposition rate, the morphology and specific surface area of ​​the precursors are controlled. The obtained carbonate precursors have a high specific surface area and a needle-like morphology.

[0009] Preferably, the carbonate precursor has a nickel content molar ratio of greater than 60% and less than 88%, a cobalt content molar ratio of greater than 3% and less than 15%, and a manganese content of greater than 6% and less than 35%.

[0010] A second aspect of the present invention provides a method for preparing the above-mentioned carbonate precursor, comprising the following steps:

[0011] (1) Add a certain weight of nickel nitrate, cobalt nitrate and manganese nitrate to a certain volume of water to prepare a nitrate solution of a certain concentration, and then add a certain amount of citric acid.

[0012] (2) Add a certain weight of urea to a certain volume of water to prepare a urea solution of a certain concentration.

[0013] (3) Heat the urea solution from step (2) to a certain temperature, and then add the solution from step (1) to the heated urea solution to react and obtain the carbonate precursor.

[0014] Preferably, in step (1), the molar ratio of citric acid to nickel, cobalt and manganese is (1-10):100.

[0015] Preferably, the molar ratio of nickel, cobalt and manganese in step (1) is (63-85):(5-7):(10-32).

[0016] Preferably, the concentration of the urea solution in step (2) is 20-50 mg / mL.

[0017] Preferably, the temperature in step (3) is 70-100℃.

[0018] Preferably, the reaction time in step (3) is 40-80 min.

[0019] A third aspect of the present invention provides a method for preparing a high-nickel single-crystal cathode material, comprising the following steps:

[0020] S1: The carbonate precursor prepared above is sintered to obtain nickel cobalt manganese oxide;

[0021] S2: The nickel cobalt manganese oxide obtained in S1 is mixed with lithium hydroxide and strontium carbonate in a certain proportion. After mixing, the molar ratio of lithium to nickel cobalt manganese is (1.04~1.10):1, and the molar ratio of strontium to nickel cobalt manganese is 1:(50~200).

[0022] S3: Sinter the material mixed in step S2 under a pure oxygen atmosphere, and then cool it naturally after sintering.

[0023] S4: The material cooled in step S3 is subjected to air jet milling to obtain the intermediate product;

[0024] S5: Mix the intermediate obtained in step S4 with cobalt hydroxide, titanium dioxide and lithium hydroxide in a certain proportion until homogeneous;

[0025] S6: The uniformly mixed material from step S5 is sintered in a pure oxygen atmosphere and then naturally cooled after sintering to obtain a high-nickel single-crystal cathode material.

[0026] Beneficial effects: This invention prepares a high specific surface area precursor by urea pyrolysis, and then obtains a high porosity precursor after pre-calcination. This can significantly reduce the high-temperature sintering temperature of high-nickel single-crystal ternary materials and effectively reduce the disproportionation reaction of trivalent nickel. The prepared high-nickel single-crystal cathode material has the characteristics of large primary particles, smooth surface, and high specific capacity.

[0027] Preferably, the sintering conditions in step S1 are: oxygen concentration > 80%, sintering temperature 750℃, and sintering time 5-7h.

[0028] Preferably, the sintering temperature in step S3 is 890-945℃, and the sintering time is 4-8h.

[0029] Preferably, in step S5, cobalt hydroxide accounts for 1% of the intermediate mass.

[0030] Preferably, the sintering temperature in step S6 is 750°C and the sintering time is 5 hours.

[0031] A fourth aspect of the present invention proposes a high-nickel single-crystal cathode material prepared using the above-described high-nickel single-crystal cathode material preparation method.

[0032] The advantages of this invention are:

[0033] 1. This invention uses urea pyrolysis to prepare carbonate precursors. It utilizes the carbon dioxide generated by urea pyrolysis to react with nickel, cobalt and manganese metal ions to prepare nickel, cobalt and manganese carbonates. By controlling the urea decomposition rate, the morphology and specific surface area of ​​the precursors are controlled. The resulting carbonate precursors have a high specific surface area and a needle-like morphology.

[0034] 2. This invention prepares a high specific surface area precursor by urea pyrolysis, and then obtains a high porosity precursor after pre-calcination. This can significantly reduce the high-temperature sintering temperature of high-nickel single-crystal ternary materials and effectively reduce the disproportionation reaction of trivalent nickel. The prepared high-nickel single-crystal cathode material has the characteristics of large primary particles, smooth surface, and high specific capacity.

[0035] 3. A carbonate precursor with high specific surface area is prepared by urea pyrolysis, and then an oxide with high porosity is prepared by pre-calcination. Finally, the high-temperature sintering temperature can be reduced to prepare high-nickel single-crystal cathode material.

[0036] 4. Compared with existing technical solutions, it has significant advantages. The high-temperature sintering temperature is reduced by 15-25℃, which effectively suppresses the disproportionation reaction of trivalent nickel, thereby producing high-nickel single-crystal cathode materials with large primary particles, smooth surfaces, and high specific capacity. Attached Figure Description

[0037] Figure 1 This is an electron microscope image of the carbonate precursor obtained in Example 1 of the present invention;

[0038] Figure 2 This is an electron microscope image of the high-nickel single-crystal cathode material prepared in Example 1 of the present invention;

[0039] Figure 3 This is an electron microscope image of the carbonate precursor obtained in Example 2 of the present invention;

[0040] Figure 4 This is an electron microscope image of the high-nickel single-crystal cathode material prepared in Example 2 of the present invention;

[0041] Figure 5 This is an electron microscope image of the carbonate precursor obtained in Example 3 of the present invention;

[0042] Figure 6 This is an electron microscope image of the high-nickel single-crystal cathode material prepared in Example 3 of the present invention;

[0043] Figure 7 This is an electron microscope image of the carbonate precursor obtained in Example 4 of the present invention;

[0044] Figure 8 This is an electron microscope image of the high-nickel single-crystal cathode material prepared in Example 4 of the present invention;

[0045] Figure 9 This is an electron microscope image of the carbonate precursor obtained in Example 5 of the present invention;

[0046] Figure 10 This is an electron microscope image of the high-nickel single-crystal cathode material prepared in Example 5 of the present invention;

[0047] Figure 11 This is an electron microscope image of the carbonate precursor obtained in Example 6 of the present invention;

[0048] Figure 12 This is an electron microscope image of the high-nickel single-crystal cathode material prepared in Example 6 of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Example 1:

[0051] A method for preparing a carbonate precursor includes the following steps:

[0052] (1) Add a certain weight of nickel nitrate, cobalt nitrate and manganese nitrate to a certain volume of water to prepare a nitrate solution of a certain concentration, and then add a certain amount of citric acid; the molar ratio of nickel, cobalt and manganese is 63:7:30; the molar ratio of citric acid to nickel, cobalt and manganese elements is 5:100.

[0053] (2) Add a certain weight of urea to a certain volume of water to prepare a urea solution with a concentration of 30 mg / mL;

[0054] (3) The urea solution from step (2) was heated to 75°C on a heater. Then, the solution from step (1) was added to the heated urea solution, and the reaction was allowed to proceed for 60 minutes to obtain the carbonate precursor (its electron micrograph is shown in Figure 1). Figure 1 As shown), its chemical formula is Ni. 0.63 Co 0.07 Mn 0.3 CO3; particle size D50 is 2-6 μm.

[0055] The preparation of high-nickel single-crystal cathode materials using the above-mentioned carbonate precursor includes the following steps:

[0056] S1: The carbonate precursor prepared above was placed in an atmosphere furnace and sintered for 6 hours at an oxygen concentration > 80% and a sintering temperature of 750°C to obtain nickel cobalt manganese oxide.

[0057] S2: The nickel cobalt manganese oxide obtained in S1 is mixed with lithium hydroxide and strontium carbonate in a certain proportion. After mixing, the molar ratio of lithium to nickel cobalt manganese is 1.05:1, and the molar ratio of strontium to nickel cobalt manganese is 1:80.

[0058] S3: Load the mixed material from step S2 into a sagger, then place it in a box furnace and sinter at 945°C for 4 hours in a pure oxygen atmosphere, and then allow it to cool naturally after sintering.

[0059] S4: The material cooled in step S3 is subjected to air jet milling to obtain the intermediate product;

[0060] S5: Mix the intermediate product from step S4 with cobalt hydroxide, titanium dioxide and lithium hydroxide in a certain proportion; wherein cobalt hydroxide accounts for 1% of the mass of the intermediate product.

[0061] S6: The uniformly mixed material from step S5 is loaded into a crucible and then placed in a box furnace for sintering at 750°C in a pure oxygen atmosphere for 5 hours. After sintering, it is allowed to cool naturally to obtain the high-nickel single-crystal cathode material (its electron micrograph is shown in Figure 1). Figure 2 (As shown).

[0062] Example 2:

[0063] A method for preparing a carbonate precursor includes the following steps:

[0064] (1) Add a certain weight of nickel nitrate, cobalt nitrate and manganese nitrate to a certain volume of water to prepare a nitrate solution of a certain concentration, and then add a certain amount of citric acid; the molar ratio of nickel, cobalt and manganese is 63:7:31; the molar ratio of citric acid to nickel, cobalt and manganese elements is 5:100.

[0065] (2) Add a certain weight of urea to a certain volume of water to prepare a urea solution with a concentration of 30 mg / mL;

[0066] (3) The urea solution from step (2) was heated to 85°C on a heater. Then, the solution from step (1) was added to the heated urea solution, and the reaction was allowed to proceed for 60 minutes to obtain the carbonate precursor (its electron micrograph is shown in Figure 1). Figure 3 As shown), its chemical formula is Ni. 0.62 Co 0.07 Mn 0.31 CO3; particle size D50 is 2-6 μm.

[0067] High-nickel single-crystal cathode materials were prepared using the aforementioned carbonate precursor (electron microscopy images are shown below). Figure 4 As shown in the figure, the preparation steps are the same as in Example 1.

[0068] Example 3:

[0069] A method for preparing a carbonate precursor includes the following steps:

[0070] (1) Add a certain weight of nickel nitrate, cobalt nitrate and manganese nitrate to a certain volume of water to prepare a nitrate solution of a certain concentration, and then add a certain amount of citric acid; the molar ratio of nickel, cobalt and manganese is 63:7:32; the molar ratio of citric acid to nickel, cobalt and manganese elements is 5:100.

[0071] (2) Add a certain weight of urea to a certain volume of water to prepare a urea solution with a concentration of 30 mg / mL;

[0072] (3) The urea solution from step (2) was heated to 85°C on a heater. Then, the solution from step (1) was added to the heated urea solution, and the reaction was allowed to proceed for 60 minutes to obtain the carbonate precursor (its electron micrograph is shown in Figure 1). Figure 5 As shown), its chemical formula is Ni. 0.618 Co 0.069 Mn 0.313 CO3; particle size D50 is 2-6 μm.

[0073] High-nickel single-crystal cathode materials were prepared using the aforementioned carbonate precursor (electron microscopy images are shown below). Figure 6 As shown in the figure, the preparation steps are the same as in Example 1.

[0074] Example 4:

[0075] A method for preparing a carbonate precursor includes the following steps:

[0076] (1) Add a certain weight of nickel nitrate, cobalt nitrate and manganese nitrate to a certain volume of water to prepare a nitrate solution of a certain concentration, and then add a certain amount of citric acid; the molar ratio of nickel, cobalt and manganese is 75:05:20; the molar ratio of citric acid to nickel, cobalt and manganese elements is 5:100.

[0077] (2) Add a certain weight of urea to a certain volume of water to prepare a urea solution with a concentration of 20 mg / mL;

[0078] (3) The urea solution from step (2) was heated to 75°C on a heater. Then, the solution from step (1) was added to the heated urea solution, and the reaction was allowed to proceed for 60 minutes to obtain the carbonate precursor (its electron micrograph is shown in Figure 1). Figure 7 As shown), its chemical formula is Ni. 0.75 Co 0.05 Mn 0.2 CO3; particle size D50 is 2-6 μm.

[0079] The preparation of high-nickel single-crystal cathode materials using the above-mentioned carbonate precursor includes the following steps:

[0080] S1: The carbonate precursor prepared above was placed in an atmosphere furnace and sintered for 5 hours at an oxygen concentration >80% and a sintering temperature of 750°C to obtain nickel cobalt manganese oxide.

[0081] S2: The nickel cobalt manganese oxide obtained in S1 is mixed with lithium hydroxide and strontium carbonate in a certain proportion. After mixing, the molar ratio of lithium to nickel cobalt manganese is 1.05:1, and the molar ratio of strontium to nickel cobalt manganese is 1:50.

[0082] S3: Load the mixed material from step S2 into a sagger, then place it in a box furnace and sinter at 915°C for 6 hours in a pure oxygen atmosphere. After sintering, allow it to cool naturally.

[0083] S4: The material cooled in step S3 is subjected to air jet milling to obtain the intermediate product;

[0084] S5: Mix the intermediate product from step S4 with cobalt hydroxide, titanium dioxide and lithium hydroxide in a certain proportion; wherein cobalt hydroxide accounts for 1% of the mass of the intermediate product.

[0085] S6: The uniformly mixed material from step S5 is loaded into a crucible and then placed in a box furnace for sintering at 750°C in a pure oxygen atmosphere for 5 hours. After sintering, it is allowed to cool naturally to obtain the high-nickel single-crystal cathode material (its electron micrograph is shown in Figure 1). Figure 8 (As shown).

[0086] Example 5:

[0087] The difference between this embodiment and embodiment 4 is that the heating temperature in step (3) is 85°C, while the other steps are the same as in embodiment 1.

[0088] The electron micrograph of the carbonate precursor prepared in this embodiment is shown below. Figure 9 As shown, the electron microscope image of the prepared high-nickel single-crystal cathode material is as follows. Figure 10 As shown.

[0089] Example 6:

[0090] The difference between this embodiment and embodiment 4 is that the heating temperature in step (3) is 95°C, while the other steps are the same as in embodiment 1.

[0091] The electron micrograph of the carbonate precursor prepared in this embodiment is shown below. Figure 11 As shown, the electron microscope image of the fabricated high-nickel single-crystal cathode material is as follows. Figure 12 As shown.

[0092] Example 7:

[0093] The difference between this embodiment and embodiment 1 is that the molar ratio of lithium to nickel, cobalt and manganese in step S2 is 1.08:1, while the other steps are the same as in embodiment 1.

[0094] Example 8:

[0095] A method for preparing a carbonate precursor includes the following steps:

[0096] (1) Add a certain weight of nickel nitrate, cobalt nitrate and manganese nitrate to a certain volume of water to prepare a nitrate solution of a certain concentration, and then add a certain amount of citric acid; the molar ratio of nickel, cobalt and manganese is 85:5:10; the molar ratio of citric acid to nickel, cobalt and manganese elements is 5:100.

[0097] (2) Add a certain weight of urea to a certain volume of water to prepare a urea solution with a concentration of 30 mg / mL;

[0098] (3) The urea solution from step (2) is heated to 75°C on a heater. Then, the solution from step (1) is added to the heated urea solution, and the reaction is carried out for 60 minutes to obtain a carbonate precursor with the chemical formula Ni. 0.85 Co 0.05 Mn 0.10 CO3; particle size D50 is 2-6 μm.

[0099] The preparation of high-nickel single-crystal cathode materials using the above-mentioned carbonate precursor includes the following steps:

[0100] S1: The carbonate precursor prepared above was placed in an atmosphere furnace and sintered for 5 hours at an oxygen concentration >80% and a sintering temperature of 750°C to obtain nickel cobalt manganese oxide.

[0101] S2: The nickel cobalt manganese oxide obtained in S1 is mixed with lithium hydroxide and strontium carbonate in a certain proportion. After mixing, the molar ratio of lithium to nickel cobalt manganese is 1.05:1, and the molar ratio of strontium to nickel cobalt manganese is 1:180.

[0102] S3: Load the mixed material from step S2 into a sagger, then place it in a box furnace and sinter at 890°C for 8 hours in a pure oxygen atmosphere. After sintering, allow it to cool naturally.

[0103] S4: The material cooled in step S3 is subjected to air jet milling to obtain the intermediate product;

[0104] S5: Mix the intermediate product from step S4 with cobalt hydroxide, titanium dioxide and lithium hydroxide in a certain proportion; wherein cobalt hydroxide accounts for 1% of the mass of the intermediate product.

[0105] S6: The uniformly mixed material from step S5 is loaded into a sagger and then placed in a box furnace for sintering at 750°C in a pure oxygen atmosphere for 5 hours. After sintering, it is naturally cooled to obtain the high-nickel single-crystal cathode material.

[0106] The morphology of the carbonate precursor and high-nickel single-crystal cathode material prepared in Examples 7 and 8 is similar to that in Example 1.

[0107] The specific surface area of ​​the carbonate precursors prepared in Examples 1-8 was tested, and the test results are recorded in Table 1 below:

[0108]

[0109] Table 1

[0110] Batteries were fabricated using the high-nickel single-crystal cathode materials obtained in Examples 1-8, and their specific capacity was tested (specific capacity = battery capacity / mass of cathode active material). The test results are recorded in Table 2 below:

[0111]

[0112]

[0113] Table 2

[0114] Based on Tables 1 and 2 and in conjunction with... Figure 1-12 It can be seen that the carbonate precursor obtained by the present invention has a needle-like morphology and a high specific surface area; the high-nickel single crystal cathode material obtained has large particles, a smooth surface, and a high specific capacity.

[0115] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a carbonate precursor, comprising the following steps: (1) Add a certain weight of nickel nitrate, cobalt nitrate and manganese nitrate to a certain volume of water to prepare a nitrate solution of a certain concentration, and then add a certain amount of citric acid; the molar ratio of citric acid to nickel, cobalt and manganese is (1-10):100; the molar ratio of nickel, cobalt and manganese is (63-85):(5-7):(10-32). (2) Add a certain weight of urea to a certain volume of water to prepare a urea solution of a certain concentration; the concentration of the urea solution is 20-50 mg / mL. (3) Heat the urea solution from step (2) to a certain temperature, and then add the solution from step (1) to the heated urea solution to react and obtain the carbonate precursor; the certain temperature is 70-100℃.

2. The method for preparing the carbonate precursor according to claim 1, characterized in that, In step (1), the molar ratio of citric acid to nickel, cobalt and manganese is 5:100; the molar ratio of nickel, cobalt and manganese in step (1) is 63:7:

30.

3. The method for preparing the carbonate precursor according to claim 1, characterized in that, The concentration of the urea solution in step (2) is 30 mg / mL.

4. The method for preparing the carbonate precursor according to claim 1, characterized in that, The temperature in step (3) is 75°C.

5. The carbonate precursor prepared by the method according to any one of claims 1-4.

6. The carbonate precursor according to claim 5, characterized in that, Its chemical formula is Ni x Co y Mn z CO3, wherein 0.60≤x≤0.88, 0.03≤y≤0.15, 0.06≤z≤0.35, x+y+z=1.00; the particle size D50 of this carbonate precursor is 2-6μm; the specific surface area of ​​this carbonate precursor is 87, 89, 92, 95, 85, 83, 86 or 96m². 2 / g.

7. A method for preparing a high-nickel single-crystal cathode material, characterized in that, Includes the following steps: S1: Sinter the carbonate precursor described in claim 5 to obtain nickel cobalt manganese oxide; S2: The nickel cobalt manganese oxide obtained in S1 is mixed with lithium hydroxide and strontium carbonate in a certain proportion. After mixing, the molar ratio of lithium to nickel cobalt manganese is (1.04~1.10):1, and the molar ratio of strontium to nickel cobalt manganese is 1:(50~200). S3: Sinter the material mixed in step S2 under a pure oxygen atmosphere, and then cool it naturally after sintering. S4: The material cooled in step S3 is subjected to air jet milling to obtain the intermediate product; S5: Mix the intermediate obtained in step S4 with cobalt hydroxide, titanium dioxide, and lithium hydroxide in a certain proportion until homogeneous; cobalt hydroxide accounts for 1% of the mass of the intermediate. S6: The uniformly mixed material from step S5 is sintered in a pure oxygen atmosphere and then naturally cooled after sintering to obtain a high-nickel single-crystal cathode material.

8. The method for preparing high-nickel single-crystal cathode material according to claim 7, characterized in that, The sintering conditions in step S1 are: oxygen concentration > 80%, sintering temperature 750℃, and sintering time 5-7h.

9. The method for preparing the high-nickel single-crystal cathode material according to claim 7, characterized in that, The sintering temperature in step S3 is 890-945℃; the sintering temperature in step S6 is 750℃.

10. The high-nickel single-crystal cathode material prepared by the preparation method according to any one of claims 7-9.

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