Tellurium modified ternary positive electrode material and preparation method and application thereof

Abstract

The invention belongs to the technical field of battery materials, and particularly relates to a tellurium modified ternary positive electrode material and a preparation method and application thereof. The preparation method of the tellurium modified ternary positive electrode material provided by the invention comprises the following steps: 1) mixing a ternary precursor, a lithium source and a first tellurium source, and performing first sintering to obtain a primary sintered product; 2) mixing the primary sintered product obtained in the step 1) with a second tellurium source, and performing secondary sintering to obtain a secondary sintered product; and 3) washing the secondary sintered product obtained in the step 2) with water, mixing with boric acid, and calcining to obtain the tellurium modified ternary positive electrode material. The tellurium modified ternary positive electrode material prepared by the preparation method disclosed by the invention is high in specific capacity and high in first efficiency and cycle performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials, and in particular relates to a tellurium-modified ternary positive electrode material and a preparation method and application thereof. Background Art

[0002] High-nickel, low-cobalt layered oxides are considered the ultimate choice for high-energy-density automotive batteries due to their high theoretical specific capacity. However, traditional polycrystalline ternary cathode materials have a rapid capacity drop and poor cycle stability due to severe structural / chemical and mechanical instability and phase transition and structural collapse caused by oxygen loss. High-nickel, low-cobalt layered oxides are considered the most promising next-generation cathode materials for high-energy-density lithium-ion batteries.

[0003] However, due to the lack of Co and Mn, high-nickel, low-cobalt layered oxides are prone to mechanical damage caused by irreversible phase transitions as cathode materials, chemical instability during storage, and structural degradation caused by corrosion reactions between the cathode and the electrolyte, resulting in poor rate capability, cycle stability, and thermal stability. The mechanical stress generated by the H2-H3 phase transition is one of the main reasons for capacity decay. In the decay state of 4.2V, the lattice volume undergoes anisotropic changes, resulting in microcracks, which propagate on the surface of the particles to form microchannels, allowing the electrolyte to penetrate into the particles. The generation of microcracks and parasitic side reactions between the cathode and electrolyte lead to serious structural instability and capacity loss. With the increase of Ni content, mechanical degradation will also increase, which is a problem that needs to be considered in the application of high-Ni cathode materials in electric vehicles. At the same time, with the increase of nickel content, the cathode material is easy to react with water and CO2 in the air to generate LiOH and Li2CO3, which will lead to high surface residual alkali. For the above reasons, the existing high-Ni cathode materials still have low first efficiency and cycle performance in practical applications, and the specific capacity still needs to be improved. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of existing high-Ni positive electrode materials in actual application, such as low initial efficiency and cycle performance, and the need to improve specific capacity, thereby providing a tellurium-modified ternary positive electrode material and its preparation method and application.

[0005] The present invention provides a method for preparing a tellurium-modified ternary cathode material, comprising the following steps:

[0006] 1) mixing a ternary precursor, a lithium source and a first tellurium source, and performing a first sintering to obtain a primary sintered product;

[0007] 2) mixing the primary sintered product obtained in step 1) with a second tellurium source, and performing a second sintering to obtain a secondary sintered product;

[0008] 3) The secondary sintered product obtained in step 2) is washed with water, mixed with a boron source, and calcined to obtain the tellurium-modified ternary positive electrode material.

[0009] Preferably, the ternary precursor in step 1) includes nickel, and the molar content of nickel in the ternary precursor accounts for more than 90% of the total molar amount of all metal elements in the ternary precursor;

[0010] Preferably, the chemical formula of the ternary precursor is Ni x Co y Mn 1-x-y (OH)2, and 0.9≤x<1, 0.01≤y<0.1.

[0011] Preferably, the lithium source in step 1) is selected from at least one of lithium hydroxide, lithium carbonate and lithium hydroxide;

[0012] The first tellurium source is selected from at least one of tellurium dioxide and tellurium trioxide;

[0013] The molar ratio of the total molar amount of metal elements in the ternary precursor, the tellurium element in the first tellurium source, and the lithium element in the lithium source is (1-a): a: (1.0-1.05), and 0.0001≤a≤0.003.

[0014] The total molar amount of the metal elements in the ternary precursor of the present invention is the sum of the molar amounts of all the metal elements in the ternary precursor. For example, for example, the ternary precursor Ni x Co y Mn 1-x-y The total molar amount of metal elements in (OH)2 is the sum of the molar amounts of nickel elements, cobalt elements and manganese elements.

[0015] Preferably, in step 1), the first sintering temperature is 600-850° C., the first sintering time is 6-15 hours, and the first sintering atmosphere is an oxygen-containing atmosphere.

[0016] Optionally, the second sintering atmosphere is an oxygen atmosphere.

[0017] Preferably, in step 2), the second sintering temperature is 400-700° C., the second sintering time is 6-10 h, and the second sintering atmosphere is an oxygen-containing atmosphere.

[0018] Optionally, the second sintering atmosphere is an air atmosphere.

[0019] Preferably, in step 2), the second tellurium source is selected from at least one of tellurium dioxide and tellurium trioxide;

[0020] The mass ratio of the primary sintered product to the second tellurium source is 1:(0.00007-0.0001);

[0021] Optionally, the second sintering step further includes a crushing and screening step.

[0022] Preferably, in step 3), the secondary sintered product obtained in step 2) is mixed with water and washed, and after washing, it is filtered and dried to obtain a dry material, and the dry material is mixed with a boron source and calcined to obtain the tellurium-modified ternary positive electrode material.

[0023] Preferably, the mass ratio of the secondary sintered product to water is (0.4-1): (0.4-1);

[0024] The mass ratio of the dry material to the boric acid is (100-200):1;

[0025] The calcination temperature is 250-350°C and the calcination time is 6-10h;

[0026] The boron source is selected from boric acid.

[0027] The present invention provides a tellurium-modified ternary positive electrode material, which is prepared by the above-mentioned method for preparing the tellurium-modified ternary positive electrode material.

[0028] The present invention provides an application of the above-mentioned tellurium-modified ternary positive electrode material in a lithium-ion battery.

[0029] The technical solution of the present invention has the following advantages:

[0030] (1) The preparation method of the tellurium-modified ternary positive electrode material provided by the present invention comprises the following steps: 1) mixing a ternary precursor, a lithium source and a first tellurium source, and performing a first sintering to obtain a primary sintered product; 2) mixing the primary sintered product obtained in step 1) with a second tellurium source, and performing a second sintering to obtain a secondary sintered product; 3) washing the secondary sintered product obtained in step 2) with boric acid, and calcining to obtain the tellurium-modified ternary positive electrode material. The present invention adjusts the particle morphology and local atomic structure by doping the first tellurium source in the bulk phase, refining the grains, and then coating the surface with the second tellurium source, thereby effectively adjusting the ligand energy level structure and inhibiting the lattice oxygen loss, and forming a Te-Ni-Ni-Te ordered superstructure in which the nickel element is doped with tellurium and the surface is coated with tellurium to inhibit the thermodynamically irreversible phase change and improve the stability of the material. The preparation method of the present invention prepares a tellurium-modified ternary positive electrode material with high specific capacity, high first efficiency and high cycle performance.

[0031] (2) The preparation method of the tellurium-modified ternary positive electrode material provided by the present invention, wherein the first tellurium source is selected from at least one of tellurium dioxide and tellurium trioxide; in step 2), the second tellurium source is selected from at least one of tellurium dioxide and tellurium trioxide; the high-valent Te can refine the grain size, thereby eliminating the stress-strain effect, and constructing a Ni-Te ordered structure with high thermodynamic stability in the transition metal layer can significantly improve the stability of lattice oxygen. The combined enhancement of particle size and atomic arrangement leads to multi-effect improvements in lattice strain and oxygen stability. The resulting structure shows that the increase in metal-oxygen binding energy and interlayer spacing reduces lattice strain at high potentials and prevents cooperative lattice distortion. In addition, the Ni-Te ordered structure effectively improves lattice oxygen stability and prevents cumulative stress strain and irreversible phase transitions. DETAILED DESCRIPTION

[0032] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0033] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0034] Example 1

[0035] This embodiment provides a method for preparing a tellurium-modified ternary cathode material, comprising the following steps:

[0036] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor, lithium hydroxide and tellurium trioxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04 The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor, the molar amount of tellurium elements in tellurium trioxide, and the molar amount of lithium elements in lithium hydroxide is 0.9992:0.0008:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 780°C for 10 hours in an oxygen atmosphere to obtain a primary sintered product.

[0037] 2) mixing the primary sintered product obtained in step 1) with tellurium dioxide in a high-speed mixer at a mass ratio of 1:0.0001, placing the mixed products in a muffle furnace, sintering them at 600° C. in an air atmosphere for 6 hours, and crushing and sieving them to obtain a secondary sintered product;

[0038] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.5:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 700 g of the dry material was mixed with 4 g of boric acid in a high-speed mixer and calcined at 280° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0039] Example 2

[0040] This embodiment provides a method for tellurium-modified ternary cathode material, comprising the following steps:

[0041] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor, lithium hydroxide and tellurium trioxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04 The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor, the molar amount of tellurium elements in tellurium trioxide, and the molar amount of lithium elements in lithium hydroxide is 0.9985:0.0015:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 780°C for 10 hours in an oxygen atmosphere to obtain a primary sintered product.

[0042] 2) mixing the primary sintered product obtained in step 1) with tellurium dioxide in a high-speed mixer at a mass ratio of 1:0.0001, placing the mixed products in a muffle furnace, sintering them at 600° C. in an air atmosphere for 6 hours, and crushing and sieving them to obtain a secondary sintered product;

[0043] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.5:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 700 g of the dry material was mixed with 4 g of boric acid in a high-speed mixer and calcined at 280° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0044] Example 3

[0045] This embodiment provides a method for preparing a tellurium-modified ternary cathode material, comprising the following steps:

[0046] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor, lithium hydroxide and tellurium trioxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor, the molar amount of tellurium elements in tellurium trioxide, and the molar amount of lithium elements in lithium hydroxide is 0.9976:0.0024:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 780°C for 10 hours in an oxygen atmosphere to obtain a primary sintered product.

[0047] 2) mixing the primary sintered product obtained in step 1) with tellurium dioxide in a high-speed mixer at a mass ratio of 1:0.0001, placing the mixed products in a muffle furnace, sintering them at 600° C. in an air atmosphere for 6 hours, and crushing and sieving them to obtain a secondary sintered product;

[0048] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.5:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 700 g of the dry material was mixed with 4 g of boric acid in a high-speed mixer and calcined at 280° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0049] Example 4

[0050] This embodiment provides a method for tellurium-modified ternary cathode material, comprising the following steps:

[0051] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor, lithium hydroxide and tellurium trioxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04 The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor, the molar amount of tellurium elements in tellurium trioxide, and the molar amount of lithium elements in lithium hydroxide is 0.9976:0.0024:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 780°C for 10 hours in an oxygen atmosphere to obtain a primary sintered product.

[0052] 2) mixing the primary sintered product obtained in step 1) with tellurium dioxide in a high-speed mixer at a mass ratio of 1:0.00007, placing the mixture in a muffle furnace, sintering at 600° C. in an air atmosphere for 6 hours, and crushing and sieving to obtain a secondary sintered product;

[0053] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.5:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 700 g of the dry material was mixed with 4 g of boric acid in a high-speed mixer and calcined at 280° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0054] Example 5

[0055] This embodiment provides a method for tellurium-modified ternary cathode material, comprising the following steps:

[0056] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor, lithium hydroxide and tellurium trioxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04 The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor, the molar amount of tellurium elements in tellurium trioxide, and the molar amount of lithium elements in lithium hydroxide is 0.9976:0.0024:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 600°C for 6 hours in an oxygen atmosphere to obtain a primary sintered product.

[0057] 2) mixing the primary sintered product obtained in step 1) with tellurium dioxide in a high-speed mixer at a mass ratio of 1:0.00007, placing the mixture in a muffle furnace, sintering for 6 hours at 400° C. in an air atmosphere, and crushing and sieving to obtain a secondary sintered product;

[0058] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.4:1 and washed. After washing, it was filtered and dried to obtain a dry material. 600 g of the dry material was mixed with 6 g of boric acid in a high-speed mixer and calcined at 250° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0059] Example 6

[0060] This embodiment provides a method for tellurium-modified ternary cathode material, comprising the following steps:

[0061] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor, lithium hydroxide and tellurium trioxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04 The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor, the molar amount of tellurium elements in tellurium trioxide, and the molar amount of lithium elements in lithium hydroxide is 0.9976:0.0024:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 850°C for 15 hours in an oxygen atmosphere to obtain a primary sintered product.

[0062] 2) mixing the primary sintered product obtained in step 1) with tellurium dioxide in a high-speed mixer at a mass ratio of 1:0.00007, placing the mixed products in a muffle furnace, sintering them in an air atmosphere at 700° C. for 10 h, and crushing and sieving them to obtain a secondary sintered product;

[0063] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water in a water-to-material ratio of 1:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 600 g of the dry material was mixed with 3 g of boric acid in a high-speed mixer and calcined at 350° C. for 10 h to obtain the tellurium-modified ternary positive electrode material.

[0064] Comparative Example 1

[0065] This comparative example provides a method for preparing a ternary positive electrode material, comprising the following steps:

[0066] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor, lithium hydroxide and tellurium trioxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04 The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor, the molar amount of tellurium elements in tellurium trioxide, and the molar amount of lithium elements in lithium hydroxide is 0.9992:0.0008:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 780°C for 10 hours in an oxygen atmosphere to obtain a primary sintered product.

[0067] 2) mixing the primary sintered product obtained in step 1) in a high-speed mixer, placing the mixed product in a muffle furnace, sintering the product in an air atmosphere at 600° C. for 6 h, and crushing and sieving the product to obtain a secondary sintered product;

[0068] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.5:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 700 g of the dry material was mixed with 4 g of boric acid in a high-speed mixer and calcined at 280° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0069] Comparative Example 2

[0070] This comparative example provides a method for preparing a ternary positive electrode material, comprising the following steps:

[0071] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor and lithium hydroxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04 The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor to the molar amount of lithium elements in lithium hydroxide is 1:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 780°C for 10 hours in an oxygen atmosphere to obtain a primary sintered product.

[0072] 2) mixing the primary sintered product obtained in step 1) with tellurium dioxide in a high-speed mixer at a mass ratio of 1:0.0001, placing the mixed products in a muffle furnace, sintering them at 600° C. in an air atmosphere for 6 hours, and crushing and sieving them to obtain a secondary sintered product;

[0073] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.5:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 700 g of the dry material was mixed with 4 g of boric acid in a high-speed mixer and calcined at 280° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0074] Comparative Example 3

[0075] This comparative example provides a method for preparing a ternary positive electrode material, comprising the following steps:

[0076] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor and lithium hydroxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04 The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor to the molar amount of lithium elements in lithium hydroxide is 1:1.04. After mixing, the mixture is placed in a muffle furnace and sintered at 780°C for 10 hours in an oxygen atmosphere to obtain a primary sintered product.

[0077] 2) mixing the primary sintered product obtained in step 1) in a high-speed mixer, placing the mixed product in a muffle furnace, sintering the product in an air atmosphere at 600° C. for 6 h, and crushing and sieving the product to obtain a secondary sintered product;

[0078] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.5:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 700 g of the dry material was mixed with 4 g of boric acid in a high-speed mixer and calcined at 280° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0079] Comparative Example 4

[0080] This comparative example provides a method for preparing a ternary positive electrode material, comprising the following steps:

[0081] 1) Ni 0.9 Co 0.06 Mn 0.04 The (OH)2 ternary precursor, lithium hydroxide and tungsten trioxide are mixed in a high-speed mixer, and Ni 0.9 Co 0.06 Mn 0.04The ratio of the total molar amount of metal elements in the (OH)2 ternary precursor, the molar amount of tungsten elements in tungsten trioxide, and the molar amount of lithium elements in lithium hydroxide is 0.9992:0.0008:1.04. After mixing, they are placed in a muffle furnace and sintered at 780°C for 10 hours in an oxygen atmosphere to obtain a primary sintered product.

[0082] 2) The primary sintered product obtained in step 1) is mixed with tungsten dioxide in a high-speed mixer at a mass ratio of 1:0.0001, and after mixing, the mixture is placed in a muffle furnace, sintered at 600° C. in an air atmosphere for 6 hours, and then crushed and sieved to obtain a secondary sintered product;

[0083] 3) 800 g of the secondary sintered product obtained in step 2) was mixed with water at a water-to-material ratio of 0.5:1 and washed with water. After washing, it was filtered and dried to obtain a dry material. 700 g of the dry material was mixed with 4 g of boric acid in a high-speed mixer and calcined at 280° C. for 6 h to obtain the tellurium-modified ternary positive electrode material.

[0084] Test Case

[0085] The ternary positive electrode materials prepared in Examples 1-6 and Comparative Examples 1-4 were used as the positive electrode main materials to prepare positive electrode sheets, N-methylpyrrolidone was used as a dispersant, the positive electrode main material: carbon black: PVDF (polyvinylidene fluoride) were mixed with an appropriate amount of dispersant at a mass ratio of 90:5:5 to prepare positive electrode slurry, the positive electrode slurry was evenly coated on an aluminum foil, and dried in an oven at 80°C for 2h to remove the dispersant to obtain a positive electrode sheet; in an argon atmosphere of a glove box, a lithium metal sheet was used as a negative electrode sheet, lithium hexafluorophosphate (LiPF6) was used as a solute in an electrolyte, and a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 1:1 was used as a solvent, and the electrolyte concentration was 1 mol / L, and the positive electrode sheet and Celgard prepared above were used. 2500 type diaphragm, and assemble into CR2032 type button lithium ion half-cell in the order of negative electrode sheet, electrolyte, diaphragm, electrolyte, and positive electrode sheet.

[0086] The button cell was placed in the Blue Electric test system for electrical performance testing. Test conditions: test temperature 25°C, first cycle charged to 4.25V at a rate of 0.2C, then discharged to 2.5V at a rate of 0.2C, this is a cycle process, the charge and discharge capacity this time is the first charge and discharge specific capacity, and its discharge specific capacity / charge specific capacity*100% is the first efficiency. After another cycle of charge and discharge at a rate of 0.2C, start the third cycle and charge and discharge at a rate of 1C for 50 cycles, record the charge and discharge specific capacity of the third cycle and the charge and discharge specific capacity of the 52nd cycle, the cycle capacity retention rate is the discharge capacity of the 52nd cycle / the discharge capacity of the third cycle*100%, the test results are shown in Table 1.

[0087] Table 1

[0088]

[0089] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a tellurium-modified ternary cathode material. It is characterized in that The following steps are involved: 1) mixing a ternary precursor, a lithium source and a first tellurium source, and performing a first sintering to obtain a primary sintered product; 2) mixing the primary sintered product obtained in step 1) with a second tellurium source, and performing a second sintering to obtain a secondary sintered product; 3) The secondary sintered product obtained in step 2) is washed with water, mixed with a boron source, and calcined to obtain the tellurium-modified ternary positive electrode material.

2. The method for preparing the tellurium-modified ternary cathode material according to claim 1, It is characterized in that The ternary precursor in step 1) includes nickel, and the molar content of nickel in the ternary precursor accounts for more than 90% of the total molar amount of all metal elements in the ternary precursor; Preferably, the chemical formula of the ternary precursor is Ni x Co y Mn 1-x-y (OH) 2 , and 0.9≤x<1, 0.01≤y<0.

1.

3. The method for preparing the tellurium-modified ternary cathode material according to claim 1 or 2, It is characterized in that The lithium source in step 1) is selected from at least one of lithium hydroxide, lithium carbonate and lithium hydroxide; The first tellurium source is selected from at least one of tellurium dioxide and tellurium trioxide; The molar ratio of the total molar amount of metal elements in the ternary precursor, the tellurium element in the first tellurium source, and the lithium element in the lithium source is (1-a): a: (1.0-1.05), and 0.0001≤a≤0.

003.

4. A method for preparing the tellurium-modified ternary cathode material according to any one of claims 1 to 3, It is characterized in that In step 1), the first sintering temperature is 600-850° C., the first sintering time is 6-15 hours, and the first sintering atmosphere is an oxygen-containing atmosphere.

5. A method for preparing the tellurium-modified ternary cathode material according to any one of claims 1 to 4, It is characterized in that In step 2), the second sintering temperature is 400-700° C., the second sintering time is 6-10 hours, and the second sintering atmosphere is an oxygen-containing atmosphere.

6. A method for preparing the tellurium-modified ternary cathode material according to any one of claims 1 to 5, It is characterized in that In step 2), the second tellurium source is selected from at least one of tellurium dioxide and tellurium trioxide; The mass ratio of the primary sintered product to the second tellurium source is 1:(0.00007-0.0001); Optionally, the second sintering step further includes a crushing and screening step.

7. A method for preparing the tellurium-modified ternary cathode material according to any one of claims 1 to 6, It is characterized in that In step 3), the secondary sintered product obtained in step 2) is mixed with water and washed, and after washing, it is filtered and dried to obtain a dry material, and the dry material is mixed with a boron source and calcined to obtain the tellurium-modified ternary positive electrode material.

8. The method for preparing the tellurium-modified ternary cathode material according to claim 7, It is characterized in that The mass ratio of the secondary sintered product to water is (0.4-1):(0.4-1); The mass ratio of the dry material to the boric acid is (100-200):1; The calcination temperature is 250-350°C and the calcination time is 6-10h; The boron source is selected from boric acid.

9. A tellurium-modified ternary cathode material, It is characterized in that The material is prepared by the method for preparing the tellurium-modified ternary positive electrode material according to any one of claims 1 to 8.

10. Use of the tellurium-modified ternary cathode material according to claim 9 in lithium-ion batteries.

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