A positive electrode material, a positive electrode sheet and a battery comprising the positive electrode material

Abstract

The present invention provides a cathode material, a cathode sheet and a battery including the cathode material. The chemical formula of the cathode material is: a[xLi2MnO3·(1−x)LiTMO2]·bLi x1 Na y1 Co 1‑ z1 M z1 O2, wherein 0 < x < 1, TM is selected from one or more of Ni, Co, and Mn, a > b, and a + b = 1, 0.8

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a positive electrode material and a positive electrode sheet and a battery comprising the positive electrode material. Background Art

[0002] With the continuous improvement of electric vehicle range and battery energy density, the capacity of commercial cathode materials such as lithium manganese oxide, lithium cobalt oxide, lithium iron phosphate and nickel cobalt manganese ternary materials has been difficult to meet the requirements of high energy density cathode materials. Therefore, the development of high energy density, high performance and low cost cathode materials has always been a hot topic in lithium ion battery research.

[0003] Among the existing positive electrode materials, lithium-rich manganese-based positive electrode materials can provide a gram capacity of more than 250mAh / g, which is far higher than the actual gram capacity of the currently commercialized positive electrode materials. It is one of the most promising positive electrode materials for the next generation of power batteries. At the same time, this material also has the advantages of low cost and environmental friendliness. However, lithium-rich manganese-based positive electrode materials also have some urgent problems to be solved: (1) The irreversible capacity caused by the oxidation of lattice oxygen in the material structure due to high operating voltage is too large, resulting in low first coulomb efficiency; (2) The rate performance of lithium-rich manganese-based positive electrode materials is poor due to low intrinsic electronic conductivity, disordered structure, and slow lithium ion diffusion; (3) Severe voltage decay during the cycle causes a decrease in energy density. These problems have seriously hindered the commercial application of lithium-rich manganese-based positive electrode materials.

[0004] For the problems of the above-mentioned lithium-rich manganese-based cathode materials, researchers have proposed many modification methods, mainly bulk / surface element doping, surface coating, component regulation, morphology regulation, and construction of oxygen vacancies, etc. However, lithium-rich manganese-based cathode materials still have problems such as low first coulomb efficiency and poor rate performance. Summary of the invention

[0005] In order to improve the deficiencies of the prior art, the purpose of the present invention is to provide a positive electrode material and a positive electrode sheet and a battery comprising the positive electrode material. The positive electrode material is a positive electrode material based on lithium-rich manganese-based modification, the positive electrode material has an O2 phase stacking structure, the positive electrode material has a high gram capacity, good cycle stability and excellent rate performance, and can improve the problems of low gram capacity, poor cycle performance and rate performance of lithium-rich manganese-based positive electrode materials.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A positive electrode material, the chemical formula of the positive electrode material is:

[0008] a[xLi 2 MnO 3·(1 - x)LiTMO 2 ·bLi x1 Na y1 Co 1-z1 M z1 O 2 , where 0 < x < 1, TM is selected from one or more of Ni, Co, and Mn, a > b, and a + b = 1, 0.8 < x1 < 1, 0 < y1 < 0.05, 0 < z1 < 0.05, and M is at least one of Al, Mg, Ti, Mn, Zr, P, Ni, and Fe.

[0009] According to an embodiment of the present invention, 0.75 ≤ a ≤ 0.95 and 0.05 ≤ b ≤ 0.25. Exemplarily, a is 0.75, 0.8, 0.85, 0.9, 0.95; b is 0.05, 0.1, 0.15, 0.2, 0.25.

[0010] According to an embodiment of the present invention, the doping of M element can improve the structural stability of the cathode material. However, when the content of the doping element is too high, it may cause excessive capacity loss. Within the range defined in this application (0 < z1 < 0.05), the structural stability can be improved while ensuring the capacity.

[0011] According to an embodiment of the present invention, the cathode material has a layered O2 phase structure.

[0012] According to an embodiment of the present invention, in the cathode material, the transition metal atoms in the transition metal layer and the lithium atoms in the lithium atom layer will form MO6 and LiO6 octahedrons with the surrounding oxygen atoms, and are alternately arranged to form a periodic layered structure. At the same time, some lithium atoms replace the transition metal atoms in the transition metal layer to form a superstructure; and in the O2 phase structure, the MO6 octahedrons and LiO6 octahedrons have both coplanar and co-edge.

[0013] According to an embodiment of the present invention, the layered O2 phase structure has a unique lithium-deficient structure, which can accommodate additional lithium ions, so that the cathode material has a high specific capacity.

[0014] According to an embodiment of the present invention, the lithium layer of the layered O2 phase structure contains a certain amount of sodium ions with a large ionic radius, and the diffusion rate of lithium ions is relatively fast, so that the rate performance of the cathode material is very excellent. Moreover, the sodium ions in the lithium layer can also act as pillars to support the crystal structure, which can improve the structural stability of the material.

[0015] According to an embodiment of the present invention, the cathode material is a cathode material modified based on lithium-rich manganese-based, which can effectively make up for the shortcomings of the lithium-rich manganese-based cathode material, and can greatly improve the initial Coulomb efficiency, cycle stability and rate performance of the lithium-rich manganese-based cathode material without reducing the specific capacity.

[0016] According to an embodiment of the present invention, the median particle size of the positive electrode material is 7 to 15 μm; when the median particle size of the positive electrode material is within this range, the compaction density of the positive electrode material can be increased; otherwise, the compaction density of the positive electrode material will be reduced, and the energy density of the battery will be reduced. In addition, when the median particle size of the positive electrode material is less than 7 μm, it is easy to increase the consumption of the electrolyte and may cause a decrease in the cycle performance. When the median particle size is greater than 15 μm, it may affect the rate performance.

[0017] According to an embodiment of the present invention, the compaction density of the positive electrode material is 3.0 to 4.0 g / cm 3 From the SEM image of the positive electrode material of the present invention (such as Figure 3 ) It can be seen that the interior of the positive electrode material of the present invention is a dense structure, which can significantly improve the compaction density of the positive electrode material, while the interior of the conventional lithium-rich manganese-based positive electrode material contains many cavities, and its compaction density is usually 2.5-2.9 g / cm 3 , the energy density does not have a great advantage, therefore, the positive electrode material of the present invention has a higher compaction density, thereby improving the energy density of the battery.

[0018] According to an embodiment of the present invention, the particles of the positive electrode material include particles having a dense structure.

[0019] According to an embodiment of the present invention, the 2θ diffraction angle of the X-ray diffraction pattern of the positive electrode material has a first diffraction peak in the range of 18 to 19°; the 2θ diffraction angle of the X-ray diffraction pattern has a second diffraction peak in the range of 20.65 to 20.75°.

[0020] According to an embodiment of the present invention, the 2θ diffraction angle of the X-ray diffraction pattern of the positive electrode material is in the range of 44 to 47°, and there are (103) crystal plane characteristic diffraction peaks and (104) crystal plane characteristic diffraction peaks of the positive electrode material.

[0021] According to an embodiment of the present invention, the positive electrode material satisfies:

[0022] 2 (104) / I (103) <3;

[0023] Among them, I (103) is the peak intensity of the characteristic diffraction peak of the (103) crystal plane of the positive electrode material; I (104) is the peak intensity of the characteristic diffraction peak of the (104) crystal plane of the positive electrode material.

[0024] According to an embodiment of the present invention, the positive electrode material satisfies: 2 (104) / I (103) ​​<3; within this range, the positive electrode material has excellent cycle performance and rate performance.

[0025] According to an embodiment of the present invention, the residual lithium in the surface of the positive electrode material is Li 2 CO 3 The content of Li 2 CO 3 The mass of the residual lithium relative to the total mass of the positive electrode material) is less than 3000ppm. Preferably, the residual lithium 2 CO 3 The content is less than 2000ppm.

[0026] According to an embodiment of the present invention, the content of LiOH in the residual lithium on the surface of the positive electrode material (i.e., the mass of LiOH in the residual lithium on the surface of the positive electrode material relative to the total mass of the positive electrode material) is less than 1000 ppm, preferably, the content of LiOH in the residual lithium is less than 800 ppm.

[0027] According to an embodiment of the present invention, when the residual lithium content of the positive electrode material is within this range, the gas production problem can be effectively alleviated to obtain a battery with high capacity, insignificant gas production, and excellent cycle and rate performance.

[0028] The present invention also provides a method for preparing the positive electrode material, which is prepared by an ion exchange method.

[0029] According to an embodiment of the present invention, the positive electrode material is prepared by the following method:

[0030] (1) adding a soluble cobalt salt and a salt containing an M element to deionized water at a molar ratio of Co:M of (1-z1):z1 to prepare a salt solution of 0.2 to 2 mol / L; dissolving a precipitant and a complexing agent in deionized water to prepare an alkaline solution with a pH of 7 to 9; then dropping the prepared salt solution and alkaline solution into the deionized water at a uniform speed, maintaining the pH between 7 and 9 and the temperature between 50 and 80° C. during the whole process, performing a coprecipitation reaction for 8 to 24 hours, and then filtering, washing, and drying the precipitate to obtain (Co 1-z1 M z1 )CO 3 Precursor or (Co 1-z1 M z1 )(OH) 2 Precursor;

[0031] (2) adding a soluble manganese salt and a salt containing TM element into deionized water at a molar ratio of Mn:TM of x:1-x to prepare a salt solution of 0.2-2 mol / L; dissolving a precipitant and a complexing agent in deionized water to prepare an alkaline solution with a pH of 7-9; then simultaneously dropping the prepared salt solution and alkaline solution into the deionized water at a uniform speed, maintaining the pH between 7 and 9 and the temperature between 50 and 80°C during the whole process, and performing a coprecipitation reaction for 8-24 hours, and then filtering, washing, and drying the precipitate to obtain Mn x TM 1-x (CO 3 ) precursor or Mn x TM 1-x (OH) 2 Precursor;

[0032] (3) the precursor of step (2) and the precursor of step (1) are mixed uniformly in a mass ratio of (95% to 75%): (5% to 25%), and then the precursor of step (2), the Na source and the Li source are weighed and mixed uniformly according to the molar ratio of Mn:Na:Li = (0.5 to 0.6): 1.1: 0.25, and pre-calcined at a temperature of 400 to 600 ° C for 1 to 5 h, and then calcined at a temperature of 800 to 1000 ° C for 12 to 30 h to obtain a Na-containing intermediate product;

[0033] (4) The Na-containing intermediate product of step (3) is mixed with a Li source in a molar ratio of Li:Na=2-5:1, calcined at a temperature of 250-300° C. for 1-4 h, and then the product is filtered, washed and dried to obtain the positive electrode material.

[0034] According to an embodiment of the present invention, in step (1) and step (2), the transition metal salt may be selected from one or more of sulfate, nitrate or chloride, and the transition metal salt is formulated according to the stoichiometric ratio in the chemical formula of the positive electrode material;

[0035] According to an embodiment of the present invention, in step (1) and step (2), the precipitant is selected from at least one of sodium carbonate, sodium hydroxide and sodium bicarbonate.

[0036] According to an embodiment of the present invention, in step (1) and step (2), the complexing agent is selected from ammonia water.

[0037] According to an embodiment of the present invention, in step (3), the Na source is selected from one or more of sodium carbonate, sodium hydroxide, and sodium chloride; and the Li source is selected from one or more of lithium carbonate, lithium hydroxide, and lithium chloride.

[0038] According to an embodiment of the present invention, in step (3) and step (4), the Li source is lithium nitrate and / or lithium chloride.

[0039] The present invention also provides a positive electrode sheet, which comprises the positive electrode material.

[0040] According to an embodiment of the present invention, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on at least one side of the positive electrode current collector, and the positive electrode active material layer includes the above-mentioned positive electrode material.

[0041] According to an embodiment of the present invention, the positive electrode active material layer further includes a conductive agent and a binder.

[0042] According to an embodiment of the present invention, the mass percentage of each component in the positive electrode active material layer is: 70-99wt% of positive electrode material, 0.5-15wt% of conductive agent, and 0.5-15wt% of binder.

[0043] Preferably, the mass percentage of each component in the positive electrode active material layer is: 80-98wt% of positive electrode material, 1-10wt% of conductive agent, and 1-10wt% of binder.

[0044] Also preferably, the mass percentage of each component in the positive electrode active material layer is: 90-96wt% of positive electrode material, 2-5wt% of conductive agent, and 2-5wt% of binder.

[0045] The present invention also provides a battery, wherein the battery comprises the above-mentioned positive electrode material, or the battery comprises the above-mentioned positive electrode sheet.

[0046] According to an embodiment of the present invention, the charging cut-off voltage of the battery is greater than or equal to 4.6V.

[0047] According to an embodiment of the present invention, the gram capacity of the positive electrode material at a charging cut-off voltage of not less than 4.6V is not less than 255 mAh / g.

[0048] Beneficial effects:

[0049] The present invention provides a positive electrode material and a positive electrode sheet and a battery comprising the positive electrode material. The positive electrode material is a positive electrode material based on lithium-rich manganese-based modification, the positive electrode material has an O2 phase stacking structure, the positive electrode material has a high gram capacity, good cycle stability and excellent rate performance, can improve the shortcomings of lithium-rich manganese-based positive electrode materials, and can greatly improve the first coulombic efficiency, cycle stability and rate performance of lithium-rich manganese-based materials without reducing gram capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 SEM spectrum of the positive electrode material in Example 1, wherein the circled part is the second diffraction peak of the positive electrode material.

[0051] Figure 2 XRD spectrum of the positive electrode material in Example 1.

[0052] Figure 3 Cross-sectional view of the positive electrode sheet containing the positive electrode material in Example 1.

[0053] Figure 4 Capacity retention curves during the cycles of Example 1 and Comparative Example 2.

[0054] Figure 5 XRD spectrum of the positive electrode material in Comparative Example 1.

[0055] Figure 6 XRD spectrum of the positive electrode material in Comparative Example 2. DETAILED DESCRIPTION

[0056] The present invention will be described in further detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0057] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the reagents, materials, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0058] The experiment will use CR2032 button cells to study the electrochemical properties of the positive electrode material of the present invention.

[0059] The positive electrode sheet adopts NMP as solvent, and the positive electrode active material (the positive electrode material prepared in the embodiment and the comparative example), the conductive agent Super P, and the binder polyvinylidene fluoride PVDF are prepared into a slurry positive electrode slurry with a solid content of 70% according to a mass ratio of 94:3:3. The positive electrode slurry is evenly coated on the surface of the aluminum foil, and baked in a vacuum oven at 100°C for 12 hours, and then rolled and cut to obtain the positive electrode sheet.

[0060] The electrolyte is 1 mol / L LiPF 6 Solution, the solvent is a mixed solvent of EC, EMC and DEC in a volume ratio of 1:1:1.

[0061] The negative electrode of the button battery uses a Li sheet, and the positive electrode uses the electrode sheet of the present invention. The positive electrode sheet, the diaphragm, the electrolyte, the Li sheet and the battery shell are assembled into a button battery in an argon-protected glove box. The performance test process of the button battery is as follows;

[0062] The test temperature is room temperature (25°C). Under the condition of charge and discharge voltage range of 2.0-4.8V, the rate performance test is first carried out, wherein the charge rate is 0.1C (1C=250mAh / g), and the discharge rates are 0.1C, 0.5C, 1C, and 2C, respectively. The rate performance test is shown in Table 1. Then, the cycle performance test is carried out under the condition of charge and discharge rate of 0.5C and voltage range of 2.0-4.6V, and the cycle is 100 cycles. The capacity retention rate after 100 cycles (%) = discharge capacity of the 104th cycle / discharge capacity of the 5th cycle × 100%.

[0063] SEM test:

[0064] The morphology, structure and element distribution of the powder can be tested and analyzed by scanning electron microscopy.

[0065] Elemental composition test:

[0066] The element content of the positive electrode material powder is tested by ICP detector; for the positive electrode sheet containing the positive electrode material, NMP can be used to dissolve the sheet, and then the powder is filtered, washed and dried to obtain the powder, and then the element content is tested and analyzed by ICP detector.

[0067] X-ray test:

[0068] Bruker D8 Advance was used to obtain the XRD spectrum and XRD refinement data of the cathode material.

[0069] Surface residual lithium test:

[0070] The surface residual lithium test is carried out by acid-base neutralization titration method to test and analyze the residual lithium content.

[0071] Compaction density test:

[0072] The compaction density of the powder material is tested and analyzed by a compaction density meter.

[0073] Example 1

[0074] The chemical formula of the positive electrode material in this embodiment is:

[0075] 0.9Li 1.14 Ni 0.13 Co 0.13 Mn 0.54 O 2 0.1Li 0.95 Na 0.025 Co 0.97 Al 0.03 O 2 , the XRD spectrum of the positive electrode material is as follows Figure 1 Its SEM morphology is shown in Figure 2The preparation steps are as follows:

[0076] (1) Add deionized water to cobalt sulfate and aluminum sulfate in a molar ratio of 0.97:0.03, add precipitant sodium hydroxide and complexing agent ammonia water in a concentration of 1.2 mol / L, wherein the molar ratio of the complexing agent to the precipitant is 0.5, adjust the pH to 7.5, precipitate, and then wash, dry and grind the precipitate to obtain a carbonate precursor Co 0.97 Al 0.03 CO 3 ;

[0077] (2) The molar ratio of Ni:Co:Mn is 0.13:0.13:0.54. Nickel sulfate, manganese sulfate and manganese sulfate are weighed and dissolved in deionized water, and stirred to obtain a salt solution; sodium carbonate as a precipitant and ammonia water as a complexing agent are added at a concentration of 2 mol / L to prepare an alkaline solution, wherein the molar ratio of the complexing agent to the precipitant is 2; then the alkaline solution and the salt solution are added dropwise to the deionized water, the pH is maintained between 7.5 and 8, and the water is heated at 60°C to perform a coprecipitation reaction, and the obtained precipitate is washed, dried and ground to obtain a carbonate precursor Ni 0.13 Mn 0.54 Co 0.13 (CO 3 ) 0.8 ;

[0078] (3) The carbonate precursor Co 0.97 Al 0.03 CO 3 and Ni 0.13 Mn 0.54 Co 0.13 (CO 3 ) 0.8 Mix them evenly in a weight ratio of 10:90, and then weigh the carbonate precursor Ni according to the molar ratio of Mn:Na:Li of 0.54:1.1:0.25. 0.13 Mn 0.54 Co 0.13 (CO 3 ) 0.8 , sodium carbonate and lithium carbonate are mixed evenly, placed in a sintering furnace in an air atmosphere, pre-fired at 500°C for 3 hours, calcined at 800°C for 16 hours, and after calcination, ground and sieved to obtain a sodium-containing intermediate product;

[0079] (4) The sodium-containing intermediate product was calcined with 2.5 times the molar amount of lithium nitrate at 280°C for 1 h, and the sintered sample was then washed with deionized water several times and dried to obtain a positive electrode material with O2 phase stacking, the compaction density of which was 3.1 g / cm 3 .

[0080] Example 2

[0081] The chemical formula of the positive electrode material in this embodiment is:

[0082] 0.85Li 1.14 Ni 0.13 Co 0.13 Mn 0.54 O 2 0.15Li 0.95 Na 0.025 Co 0.97 Al 0.03 O 2 .

[0083] The preparation process of the positive electrode material is the same as that of Example 1, except that in step (3), Co 0.97 Al 0.03 CO 3 and Ni 0.13 Mn 0.54 Co 0.13 (CO 3 ) 0.8 The weight ratio is 15:85, and its compacted density is 3.2g / cm 3 .

[0084] Example 3

[0085] The chemical formula of the positive electrode material in this embodiment is:

[0086] 0.8Li 1.14 Ni 0.13 Co 0.13 Mn 0.54 O 2 0.2Li 0.95 Na 0.025 Co 0.97 Al 0.03 O 2 .

[0087] The preparation process of the positive electrode material is the same as that of Example 1, except that in step (3), Co 0.97 Al 0.03 CO 3 and Ni 0.13 Mn 0.54 Co 0.13 (CO 3 ) 0.8 The weight ratio is 20:80, and its compacted density is 3.3g / cm 3 .

[0088] Comparative Example 1

[0089] The chemical formula of the positive electrode material in this comparative example is: Li 1.14 Ni0.13 Co 0.13 Mn 0.54 O 2 The preparation process is the same as in Example 1, except that in step (3) Co 0.97 Al 0.03 CO 3 The content is 0, and its compacted density is 2.8g / cm 3 .

[0090] Comparative Example 2

[0091] The chemical formula of the positive electrode material in this comparative example is:

[0092] 0.5Li 1.14 Ni 0.13 Co 0.13 Mn 0.54 O 2 0.5Li 0.95 Na 0.025 Co 0.97 Al 0.03 O 2 .

[0093] The preparation process of the positive electrode material is the same as that of Example 1, except that in step (3), Co 0.97 Al 0.03 CO 3 and Ni 0.13 Mn 0.54 Co 0.13 (CO 3 ) 0.8 The weight ratio is 50:50.

[0094] Comparative Example 3

[0095] The chemical formula of the positive electrode material in this comparative example is: Li 0.95 Na 0.025 Co 0.97 Al 0.03 O 2 The preparation process is the same as in Example 1, except that in step (3) Ni 0.13 Mn 0.54 Co 0.13 (CO 3 ) 0.8 The content is 0.

[0096] Table 1 Electrochemical performance test results of positive electrode materials in Examples and Comparative Examples

[0097]

[0098] It can be seen from the electrochemical performance test results in Table 1 that the positive electrode material of the present invention can effectively make up for the shortcomings of the lithium-rich manganese-based positive electrode material, and greatly improve the first coulombic efficiency, cycle stability and rate performance of the lithium-rich manganese-based positive electrode material without reducing the gram capacity.

[0099] from Figure 3 It can be seen that the interior of the positive electrode material of the present invention is a dense structure, indicating that the particles of the positive electrode material of the present invention include particles with a dense structure. It is precisely because the particles of the positive electrode material include particles with a dense structure that the compaction density of the positive electrode material reaches 3.0 to 4.0 g / cm 3 , while the conventional lithium-rich manganese-based positive electrode material contains many cavities inside and cannot achieve the high compaction density of the present application. This shows that the use of the positive electrode material of the present invention can increase the compaction density of the positive electrode sheet, thereby increasing the energy density of the battery.

[0100] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A positive electrode material, It is characterized in that The chemical formula of the positive electrode material is: a[xLi 2 MnO 3 ·(1 - x)LiTMO 2 ·bLi x1 Na y1 Co 1-z1 M z1 O 2 , where 0 < x < 1, TM is selected from one or more of Ni, Co, and Mn, a > b, and a + b = 1, 0.8 < x1 < 1, 0 < y1 < 0.05, 0 < z1 < 0.05, M is at least one of Al, Mg, Ti, Mn, Zr, P, Ni, and Fe; 0.75 ≤ a ≤ 0.95, 0.05 ≤ b ≤ 0.25; The positive electrode material has a layered O2 phase structure.

2. The positive electrode material according to claim 1, It is characterized in that The positive electrode material has an X-ray diffraction pattern with a 2θ diffraction angle in the range of 18 to 19 degrees and a first diffraction peak; and has an X-ray diffraction pattern with a 2θ diffraction angle in the range of 20.65 to 20.75 degrees and a second diffraction peak.

3. The positive electrode material according to claim 1, It is characterized in that The positive electrode material satisfies: 2<I (104) / I (103) <3; Among them, I (103) is the peak intensity of the characteristic diffraction peak of the (103) crystal plane of the positive electrode material; I (104) is the peak intensity of the characteristic diffraction peak of the (104) crystal plane of the positive electrode material.

4. The positive electrode material according to claim 1, It is characterized in that The median particle size of the positive electrode material is 7-15 μm.

5. The positive electrode material according to claim 1, It is characterized in that The compaction density of the positive electrode material is 3.0-4.0 g / cm 3 .

6. The positive electrode material according to claim 1, It is characterized in that The residual lithium in the surface of the positive electrode material 2 CO 3 The content is less than 3000ppm; and / or; the content of LiOH in the residual lithium on the surface of the positive electrode material is less than 1000ppm.

7. A positive electrode sheet, It is characterized in that The positive electrode sheet comprises the positive electrode material according to any one of claims 1 to 6.

8. A battery, It is characterized in that The battery comprises the positive electrode material according to any one of claims 1 to 6, or the battery comprises the positive electrode sheet according to claim 7.

9. The battery according to claim 8, It is characterized in that When the charging cut-off voltage of the positive electrode material is greater than or equal to 4.6V, the 0.1C discharge capacity exceeds 255mAh / g.

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