Aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material, preparation method thereof and lithium ion battery

Abstract

The invention discloses an aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material, a preparation method thereof and a lithium ion battery. The preparation method comprises the following steps: uniformly adsorbing an yttrium source on the surface of a binary cobalt-free precursor Ni0. 90Mn0. 10 (OH) 2 by an aluminum isopropoxide hydrolysis method, drying and sieving to obtain a pretreated mixture; and grinding and uniformly mixing the mixture and a lithium source, carrying out primary calcination for 4-6 hours at the temperature of 400-600 DEG C in an oxygen atmosphere, carrying out secondary calcination for 12-16 hours at the temperature of 700-800 DEG C, cooling, grinding and screening to obtain the aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material. Compared with a coprecipitation method, a spray drying method, an atomic vapor deposition method and the like, the preparation method is simple to operate and lower in cost, uniform doping and coating of particles can be realized, and the obtained positive electrode material has the advantages of uniform particle size, high crystallinity, stable structure and good cycle performance.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to an aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material, a preparation method thereof, and a lithium ion battery. Background Art

[0002] In recent years, the development of high-nickel ternary cathodes has been hampered by limited cobalt reserves and high toxicity. Driven by economic, social, and safety factors, high-nickel, cobalt-free cathode materials have gained favor with researchers for their high specific capacity, environmental friendliness, and low cost, making them a promising candidate for the development of high-energy-density lithium-ion batteries.

[0003] CN118877950A uses spray pyrolysis to achieve uniform distribution of aluminum in a high-nickel material, while also synergistically combining it with a ceria surface coating to improve the material's cycling performance, thermal stability, and conductivity. However, since spray pyrolysis requires high temperatures and vacuum conditions, it places high demands on equipment and operation, and the resulting particle size is highly dependent on the spray process parameters, making it difficult to commercialize.

[0004] CN118538894A prepared a molybdenum-doped and double-coated high-nickel cobalt-free cathode material, the inner layer of which is aluminum and the outer layer is PPy. The material's cycling stability is enhanced, and the discharge specific capacity is improved. However, this method does not consider that the high-valence molybdenum will trigger charge balance, resulting in severe cation mixing. In addition, the inactive aluminum coating inner layer and the high-temperature structurally unstable PPy outer layer both hinder the performance of the cathode material to a certain extent.

[0005] However, high-nickel, cobalt-free cathode materials still have problems such as structural instability, poor cycle stability, and poor thermal stability, which require further research and resolution. Therefore, the development of high-nickel, cobalt-free cathode materials with high specific capacity, structural stability, and excellent cycle performance is urgent. Summary of the Invention

[0006] To address the problems of the prior art, the present invention proposes an aluminum- and lithium yttrium-modified high-nickel, cobalt-free lithium-ion battery cathode material and a method for preparing the same. Bulk doping with aluminum effectively stabilizes the bulk structure of the material due to its strong metal-oxygen bonds and excellent thermal stability. The lithium yttrium oxide layer formed in situ on the surface acts as a protective barrier, separating the active material from the electrolyte and effectively reducing side reactions with the electrolyte and hydrogen fluoride corrosion. This synergistic bulk-surface modification strategy significantly mitigates interfacial side reactions and crystal structure degradation, thereby significantly improving the material's cycling stability and structural reliability.

[0007] The present invention also discloses a lithium ion battery, which uses aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material as the positive electrode material to improve cycle stability and structural reliability.

[0008] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0009] A method for preparing a high nickel cobalt-free lithium ion battery positive electrode material modified by aluminum and lithium yttrium oxide, comprising the following steps: hydrolyzing a binary cobalt-free precursor Ni by aluminum isopropoxide; 0.90 Mn 0.10 The yttrium source is uniformly adsorbed on the surface of (OH)2, and the mixture is dried and sieved to obtain a pretreated mixture; the pretreated mixture is then ground and mixed evenly with a lithium source, and calcined twice under an oxygen atmosphere, wherein the first calcination is at 400-600°C for 4-6 hours, and the second calcination is at 700-800°C for 12-16 hours. After cooling, grinding and sieving, an aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material is obtained; the composition of the aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material is n(Li):n(Ni+Mn+Al):n(Y)=(1.05+x):1:x; wherein 0.005≤x≤0.015.

[0010] As an improvement, the binary cobalt-free precursor Ni 0.90 Mn 0.10 (OH)2 is first dried in vacuum at 60-100°C.

[0011] As an improvement, the aluminum source is aluminum isopropoxide, the yttrium source is yttrium oxide, and the mass ratio of the binary cobalt-free precursor to aluminum isopropoxide and yttrium oxide is 2.7720-2.7538:0.1909-0.3203:0.0175-0.0520. 21 The material prepared with AlO3 as the aluminum source has a low degree of Li / Ni mixing and has excellent cycle performance.

[0012] As an improvement, the grinding time of the pretreated mixture and the lithium source is 7-13 minutes.

[0013] A further improvement is that the grinding time of the pretreated mixture and the lithium source is 8-12 minutes. Sufficient grinding without excessive grinding that causes particle breakage is beneficial to improving the degree of ordering of the material structure and reducing cation mixing.

[0014] As an improvement, the two calcinations are respectively carried out at 480-520° C. for the first time for 4-6 h and at 700-800° C. for the second time for 12-16 h.

[0015] As an improvement, the oxygen flow rate is 140-200mLmin–1 .

[0016] A further improvement is that the oxygen flow rate is 150-200mLmin –1 This oxygen flow rate is beneficial to ensuring the oxygen content in the positive electrode material, thereby ensuring the electrochemical performance of the positive electrode material.

[0017] As an improvement, the powder is ground and sieved to 200-400 mesh.

[0018] A lithium-ion battery adopts the aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium-ion battery positive electrode material as the positive electrode material.

[0019] The present invention starts from a simple aluminum isopropoxide hydrolysis method, uniformly adsorbs yttrium source particles on the surface of the precursor, adds a lithium source to the dried and sieved mixture and grinds it evenly, and combines it with subsequent high-temperature solid-phase sintering to obtain a high-nickel cobalt-free positive electrode material coated with aluminum-doped lithium yttrium. Through the modification of aluminum and lithium yttrium, the doping of aluminum elements in the bulk phase of the particles is achieved. Since aluminum has a strong metal-oxygen bond and good thermal stability, the bulk structure of the material can be effectively stabilized. The lithium yttrium layer formed in situ on the surface has high ionic conductivity and can act as a protective barrier, separating the active substance from the electrolyte, effectively reducing side reactions with the electrolyte and corrosion by hydrogen fluoride. This body-surface collaborative modification strategy greatly alleviates interface problems and crystal structure degradation, thereby obtaining good electrochemical performance. The present invention simplifies the preparation method by optimizing the sintering temperature and the ratio of each element, while improving cycle stability and structural reliability. This body-surface synergistic design and simple hydrolysis-solid-phase sintering preparation process effectively alleviate the structural instability, poor cycle stability and thermal stability of high-nickel cobalt-free positive electrodes.

[0020] Compared with existing technologies, the present invention offers the following advantages: The modification method proposed herein utilizes aluminum doping in the bulk phase. Due to aluminum's strong metal-oxygen bonds and excellent thermal stability, it effectively stabilizes the material's layered structure and inhibits Li / Ni mixing. The in-situ lithium yttrium oxide layer formed on the surface acts as a protective barrier, separating the active material from the electrolyte, effectively reducing side reactions with the electrolyte and hydrogen fluoride corrosion. Furthermore, the lithium yttrium oxide coating with high ionic conductivity effectively promotes ion transport. This synergistic bulk-surface modification strategy significantly alleviates interfacial issues and crystal structure degradation. The resulting material exhibits excellent electrochemical performance, with a capacity retention of up to 99.2% after 100 cycles at 2.7-4.3V. Furthermore, the cathode material prepared by this method exhibits advantages such as uniform chemical composition, high purity, uniform particle size, low heat treatment temperature, precise control of the stoichiometric ratio, simple operation, easily controlled conditions, good reproducibility, and stable electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 XRD patterns of the positive electrode materials prepared in Comparative Example 3, Examples 1-4, and Comparative Examples 6-8;

[0022] Figure 2 Cycling capacity retention curves of the positive electrode materials prepared in Comparative Example 3, Comparative Example 7, and Examples 1-4;

[0023] Figure 3 This is an SEM image of the positive electrode material prepared in Comparative Example 3;

[0024] Figure 4 This is the SEM image of the positive electrode material prepared in Example 2. DETAILED DESCRIPTION

[0025] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise specified, the equipment and reagents used in the present invention are conventional commercial products in this technical field. The room temperature proposed in the present invention refers to 25°C.

[0026] A method for preparing a high nickel cobalt-free lithium ion battery positive electrode material modified by aluminum and lithium yttrium oxide, comprising the following steps: hydrolyzing a binary cobalt-free precursor Ni by aluminum isopropoxide; 0.90 Mn 0.10 The yttrium source is uniformly adsorbed on the surface of (OH)2, and the mixture is dried and sieved to obtain a pretreated mixture; the pretreated mixture is then ground and mixed evenly with a lithium source, and calcined twice under an oxygen atmosphere, wherein the first calcination is at 400-600°C for 4-6 hours, and the second calcination is at 700-800°C for 12-16 hours. After cooling, grinding and sieving, an aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material is obtained; the composition of the aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material is n(Li):n(Ni+Mn+Al):n(Y)=(1.05+x):1:x; wherein 0.005≤x≤0.015.

[0027] Specifically, the binary cobalt-free precursor Ni 0.90 Mn 0.10 (OH)2 is first dried in vacuum at 60-100°C.

[0028] The aluminum source is aluminum isopropoxide with a purity of 99.99%, and the yttrium source is yttrium oxide with a purity of 99%. The mass ratio of the binary cobalt-free precursor to aluminum isopropoxide and yttrium oxide is 2.7720-2.7538:0.1909-0.3203:0.0175-0.0520. Y2O3 is the yttrium source, C9H 21 The material prepared with AlO3 as the aluminum source has a low degree of Li / Ni mixing and has excellent cycle performance.

[0029] The time for grinding the precursor mixture and the lithium source is 7-13 minutes.

[0030] The precursor mixture and the lithium source are ground for 8-12 minutes. Grinding thoroughly and avoiding excessive grinding that causes particle breakage is beneficial to improving the degree of ordering of the material structure and reducing cation mixing.

[0031] The two calcinations are respectively a first calcination at 480-520° C. for 4-6 h and a second calcination at 700-800° C. for 12-16 h.

[0032] The oxygen flow rate is 140-200mLmin –1 More preferably, the oxygen flow rate is 150-200 mL / min. –1 This oxygen flow rate is beneficial to ensuring the oxygen content in the positive electrode material, thereby ensuring the electrochemical performance of the positive electrode material.

[0033] Grind and sieve to 200-400 mesh.

[0034] Example 1

[0035] Weigh 2.7538g Ni 0.90 Mn 0.10 (OH)2 powder and 0.2539g C9H 21 AlO3 and 0.0175g Y2O3 were uniformly mixed by aluminum isopropoxide hydrolysis method, and then 1.8981g of the above mixture was ground with 0.9219g LiOH·H2O for 8min to mix evenly, wherein (Li):(Ni+Mn+Al+Y):(O)=1.05:1:2 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 750℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 ) 0.955 Al 0.04 Y 0.005 O2 material.

[0036] Example 2

[0037] Weigh 2.7458g Ni 0.90 Mn 0.10 (OH)2 powder and 0.2531g C9H 21 AlO3 and 0.0262g Y2O3 were uniformly mixed by aluminum isopropoxide hydrolysis method, and then 1.8984g of the above mixture was ground with 0.9192g LiOH·H2O for 8min to mix evenly, wherein (Li):(Ni+Mn+Al+Y):(O)=1.05:1:2 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 750℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 ) 0.9525 Al 0.04 Y 0.075 O2 material.

[0038] Example 3

[0039] Weigh 2.7378g Ni 0.90 Mn 0.10 (OH)2 powder and 0.2524g C9H 21 AlO3 and 0.0349g Y2O3 were uniformly mixed by aluminum isopropoxide hydrolysis method, and then 1.8987g of the above mixture was ground with 0.9165g LiOH·H2O for 8min to mix evenly, wherein (Li):(Ni+Mn+Al+Y):(O)=1.05:1:2 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 750℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 ) 0.95 Al 0.04 Y 0.01 O2 material.

[0040] Example 4

[0041] Weigh 2.7220gNi 0.90 Mn 0.10 (OH)2 powder and 0.2509g C9H 21AlO3 and 0.052g Y2O3 were uniformly mixed by aluminum isopropoxide hydrolysis method, and then 1.8993g of the above mixture was ground with 0.9113g LiOH·H2O for 8min to mix evenly, wherein (Li):(Ni+Mn+Al+Y):(O)=1.05:1:2 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 750℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 ) 0.945 Al 0.04 Y 0.015 O2 material.

[0042] Comparative Example 1

[0043] Weigh 2.8482g Ni 0.90 Mn 0.10 (OH)2 powder was ground with 1.3728g LiOH·H2O for 8min and mixed evenly, wherein Li:(Ni+Mn)=1.05:1 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1 The LiNi was sintered in a tube furnace, first at 500℃ for 5h, then at 700℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 O2 material.

[0044] Comparative Example 2

[0045] Weigh 2.8482g Ni 0.90 Mn 0.10 (OH)2 powder was ground with 1.3728g LiOH·H2O for 8min and mixed evenly, wherein Li:(Ni+Mn)=1.05:1 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 730℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 O2 material.

[0046] Comparative Example 3

[0047] Weigh 2.8482g Ni 0.90 Mn 0.10 (OH)2 powder was ground with 1.3728g LiOH·H2O for 8min and mixed evenly, wherein Li:(Ni+Mn)=1.05:1 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 750℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 O2 material.

[0048] Comparative Example 4

[0049] Weigh 2.8482g Ni 0.90 Mn 0.10 (OH)2 powder was ground with 1.3728g LiOH·H2O for 8min and mixed evenly, wherein Li:(Ni+Mn)=1.05:1 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 775℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 O2 material. The test results of button batteries made with this material are shown in Table 2.

[0050] Comparative Example 5

[0051] Weigh 2.8482g Ni 0.90 Mn 0.10 (OH)2 powder was ground with 1.3728g LiOH·H2O for 8min and mixed evenly, wherein Li:(Ni+Mn)=1.05:1 (molar ratio), and placed in an oxygen flow rate of 150mLmin –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 800℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 O2 material.

[0052] Comparative Example 6

[0053] Weigh 2.7898g Ni 0.90 Mn 0.10 (OH)2 powder and 0.1909g C9H 21 AlO3 was uniformly mixed by aluminum isopropoxide hydrolysis method, and then 1.8978g of the above mixture was ground with 0.9243g LiOH·H2O for 8min to mix evenly, wherein (Li):(Ni+Mn+Al):(O)=1.05:1:2 (molar ratio), and placed in an oxygen flow rate of 150mL min –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 750℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 ) 0.97Al 0.03 O2 material.

[0054] Comparative Example 7

[0055] Weigh 2.7700g Ni 0.90 Mn 0.10 (OH)2 powder and 0.2554g C9H 21 AlO3 was uniformly mixed by aluminum isopropoxide hydrolysis method, and then 1.8975g of the above mixture was ground with 0.9274g LiOH·H2O for 8min to mix evenly, wherein (Li):(Ni+Mn+Al):(O)=1.05:1:2 (molar ratio), and placed in an oxygen flow rate of 150mL min –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 750℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 ) 0.96 Al 0.04 O2 material.

[0056] Comparative Example 8

[0057] Weigh 2.7501gNi 0.90 Mn 0.10 (OH)2 powder and 0.3203g C9H 21 AlO3 was uniformly mixed by aluminum isopropoxide hydrolysis method, and then 1.8972g of the above mixture was ground with 0.9304g LiOH·H2O for 8min to mix evenly, wherein (Li):(Ni+Mn+Al):(O)=1.05:1:2 (molar ratio), and placed in an oxygen flow rate of 150mL min –1 The sintering was carried out in a tube furnace, first at 500℃ for 5h, then at 750℃ for 14h, and finally cooled to room temperature. 0.90 Mn 0.10 ) 0.94 Al 0.05 O2 material.

[0058] Table 1 Parameters of different embodiments and comparative examples

[0059]

[0060] The positive electrode materials obtained in the above examples 1-4 and comparative examples 1-8 were made into 2032-type button-type simulated batteries to test their electrochemical performance. The specific steps are as follows: (1) The above positive electrode materials, conductive acetylene black and polyvinylidene fluoride (PVDF) were weighed in a mass ratio of 80:10:10 respectively, and PVDF was first dissolved in an appropriate amount of N-methylpyrrolidone (NMP), and then the mixed positive electrode materials and acetylene black powder were added to NMP and stirred to form a slurry; (2) The slurry was evenly coated on an aluminum foil substrate, and the wet electrode was placed in a vacuum drying oven, dried at 110°C for 12 hours and cut into positive electrode sheets; (3) In a dry vacuum glove box, a simulated battery was assembled. The above self-made electrode sheet was used as the positive electrode, the metal lithium sheet was used as the negative electrode, the Celgard2500 membrane was used as the diaphragm, and 1 mol L –1 The electrochemical properties of LiPF6 were tested by dissolving it in ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) (volume ratio 1:1:1) as the electrolyte, and the specific performance is shown in Table 2.

[0061] Table 2 Electrochemical performance of positive electrode materials of Examples 1-7 and Comparative Examples 1-5 at 2.7-4.3V

[0062]

[0063] From Table 2, it can be seen that after 100 cycles at a rate of 1C, the discharge capacity of the material in Example 2 is still 165.8 mAh g –1 The capacity retention rate reached 99.2%, there was no obvious capacity attenuation, and the cycle stability was better than that of Comparative Example 3 and Comparative Examples 6 to 8. This is related to the introduction of aluminum yttrium elements, which synergistically improved the performance of the original material.

[0064] Figure 1 XRD spectra of positive electrode materials synthesized with different ratios of aluminum source and yttrium source. It can be seen that the peak shapes and peak positions of Comparative Example 3, Examples 1-4, and Comparative Examples 6-8 are basically the same, and strong characteristic peaks can be observed, and there are no impurity peaks. The positive electrode materials before and after modification with aluminum and lithium yttrium oxide all show typical structural characteristics of LiNiO2 positive electrode materials, and their diffraction peaks are characteristic peaks of α-NaFeO2 layered structures, belonging to the hexagonal system and R-3m space group. The two pairs of diffraction peaks (006) / (012) and (018) / (110) of the positive electrode materials of Examples 1-4 and Comparative Examples 6-8 are obviously split, forming a better layered structure. Compared with Example 2, the I of Comparative Example 3 (003) / I (104) Relatively smaller, indicating that the Li + / Ni 2+ The degree of mixing is low. Figure 2 It shows that Example 2 shows a better cycle capacity retention rate than Comparative Example 3. Figure 3and Figure 4 It can be seen that the positive electrode materials of Example 2 and Comparative Example 3 are both composed of secondary particles with a particle size of about 1-3 μm formed by agglomeration of primary particles.

[0065] In summary, the present invention uses aluminum to dope the bulk phase of particles. Since aluminum has strong metal-oxygen bonds and good thermal stability, the bulk structure of the material is effectively stabilized. The lithium yttrium oxide layer formed in situ on the surface can act as a protective barrier, reducing the side reactions between the active material and the electrolyte and the corrosion of hydrogen fluoride; and the lithium yttrium oxide coating layer with high ionic conductivity effectively promotes ion transport. This bulk-surface synergistic modification strategy greatly alleviates the interface side reactions and crystal structure degradation, so that the material has excellent electrochemical properties. In addition, the positive electrode material of the present invention has the advantages of uniform chemical composition, high purity, uniform particle size, low heat treatment temperature, precise control of stoichiometric ratio, simple operation, easy to control conditions, good reproducibility, and stable electrochemical performance.

[0066] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a high-nickel cobalt-free lithium-ion battery positive electrode material modified by aluminum and lithium yttrium oxide, characterized in that: The following steps are included: using aluminum isopropoxide hydrolysis method to prepare a binary cobalt-free precursor Ni 0.90 Mn 0.10 The yttrium source is uniformly adsorbed on the surface of (OH)2, and the mixture is dried and sieved to obtain a pretreated mixture; the pretreated mixture is then ground and mixed evenly with a lithium source, and calcined twice under an oxygen atmosphere, wherein the first calcination is at 400-600°C for 4-6 hours, and the second calcination is at 700-800°C for 12-16 hours. After cooling, grinding and sieving, an aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material is obtained; the composition of the aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium ion battery positive electrode material is n(Li):n(Ni+Mn+Al):n(Y)=(1.05+x):1:x; wherein 0.005≤x≤0.

015.

2. The method for preparing a high-nickel cobalt-free lithium-ion battery positive electrode material modified by aluminum and lithium yttrium oxide according to claim 1, characterized in that: The binary cobalt-free precursor Ni 0.90 Mn 0.10 (OH)2 is first vacuum dried in an oven at 60-100℃.

3. The method for preparing a high-nickel cobalt-free lithium-ion battery positive electrode material modified by aluminum and lithium yttrium oxide according to claim 1, characterized in that: The aluminum source is aluminum isopropoxide, the yttrium source is yttrium oxide, and the mass ratio of the binary cobalt-free precursor to aluminum isopropoxide and yttrium oxide is 2.7720-2.7538:0.1909-0.3203:0.0175-0.0520.

4. The method for preparing a high-nickel cobalt-free lithium-ion battery positive electrode material modified by aluminum and lithium yttrium oxide according to claim 1, characterized in that: The time for grinding the pretreated mixture and the lithium source is 7-13 minutes.

5. The method for preparing a high-nickel cobalt-free lithium-ion battery positive electrode material modified by aluminum and lithium yttrium oxide according to claim 4, characterized in that: The time for grinding the pretreated mixture and the lithium source is 8-12 minutes.

6. The method for preparing a high-nickel cobalt-free lithium-ion battery positive electrode material modified by aluminum and lithium yttrium oxide according to claim 1, characterized in that: The two calcinations are respectively carried out at 480-520° C. for the first time for 4-6 h and at 700-800° C. for the second time for 12-16 h.

7. The method for preparing a high-nickel cobalt-free lithium-ion battery positive electrode material modified by aluminum and lithium yttrium oxide according to claim 1, characterized in that: The oxygen flow rate is 140-200mLmin –1 .

8. The method for preparing an aluminum and lithium yttrium oxide modified high nickel cobalt-free lithium ion battery positive electrode material according to claim 7, characterized in that: The oxygen flow rate is 150-200mLmin –1 .

9. The method for preparing a high-nickel cobalt-free lithium-ion battery positive electrode material modified by aluminum and lithium yttrium oxide according to claim 1, characterized in that: Grind and sieve to 200-400 mesh.

10. A lithium-ion battery, using the aluminum and lithium yttrium oxide modified high-nickel cobalt-free lithium-ion battery positive electrode material prepared by the preparation method according to any one of claims 1 to 9 as a positive electrode material.

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