High-nickel ternary positive electrode material, preparation method thereof and battery

Abstract

The invention belongs to the technical field of preparation of high-nickel ternary positive electrode materials, and discloses a high-nickel ternary positive electrode material, a preparation method thereof and a battery, and the preparation method comprises the following steps: mixing and grinding a ternary positive electrode precursor nickel cobalt manganese oxide, a lithium source, a magnesium source and a niobium source in proportion, and then calcining in an oxygen atmosphere to obtain a ternary positive electrode material intermediate; wherein the mass ratio of the magnesium element to the nickel cobalt lithium manganate is 1000-2000ppm, and the mass ratio of the niobium element to the nickel cobalt lithium manganate is 1500-2500ppm; adding the ternary positive electrode material intermediate into a phosphate solution or a phosphoric acid solution, fully stirring and dispersing, and then drying the feed liquid to obtain a solid material; and calcining the dried solid material in an oxygen atmosphere at 500-700 DEG C for 6-10 hours to obtain the catalyst. The problems that the surface of the high-nickel ternary positive electrode material is unstable, transition metal is dissolved, electrolyte is corroded, the structure is easy to damage and oxygen is easy to separate out under high voltage, so that the high-nickel ternary positive electrode material is short in service life and poor in cycle performance under high voltage can be effectively solved.

Description

Technical Field

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

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] The rapid development of electric vehicles has exacerbated range anxiety, leading to a surge in demand for high-energy-density materials for lithium batteries. High-nickel ternary cathode material Li(Ni) x Co y Mn 1-x-y O2 (LNCM) possesses high specific capacity and energy density, making it a promising cathode material for power lithium-ion batteries. However, high-nickel ternary cathode materials suffer from problems such as easy phase transitions in surface particles, poor rate and cycle performance, unstable surface structure, poor thermal stability, and oxygen evolution under high voltage. Elemental doping can improve the electrochemical performance of high-nickel ternary materials to some extent.

[0004] Introducing niobium into nickel-cobalt-manganese ternary materials can, to some extent, improve the stability of the cathode material and expand the Li-type cathode material. + Insertion / extraction channels and reduction of cation mixing can improve material properties. Current technologies primarily use niobium pentoxide as a dopant, mixing it with the precursor and calcining it under normal pressure for doping modification, but the modification effect is unsatisfactory.

[0005] Another approach involves incorporating nanoscale niobium compounds into high-nickel ternary cathode materials, effectively improving the conductivity and discharge specific capacity of the cathode material. However, ion doping only affects the internal structure of the cathode material; problems such as surface instability, transition metal dissolution, electrolyte corrosion, and oxygen evolution under high voltage are difficult to effectively address. This forces high-nickel ternary cathode materials to reduce their actual operating voltage window, limiting the improvement of their energy density and hindering their application. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a high-nickel ternary cathode material, its preparation method, and a battery thereof.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a method for preparing a high-nickel ternary cathode material, comprising the following steps: The ternary cathode precursor nickel cobalt manganese oxide, lithium source, magnesium source and niobium source are mixed and ground in proportion, and then calcined in an oxygen atmosphere to obtain a ternary cathode material intermediate. The mass ratio of magnesium to lithium nickel cobalt manganese oxide is 1000-2000ppm, and the mass ratio of niobium to lithium nickel cobalt manganese oxide is 1500-2500ppm. The ternary cathode material intermediate is added to a phosphate solution or a phosphoric acid solution, stirred and dispersed thoroughly, and then the solution is dried. The dried solid material is calcined at 500-700℃ for 6-10 hours in an oxygen atmosphere to obtain the final product.

[0008] Secondly, the present invention provides a high-nickel ternary cathode material, which is prepared by the aforementioned preparation method.

[0009] Thirdly, the present invention provides a battery in which the active material on the positive electrode plate is the high-nickel ternary positive electrode material.

[0010] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows: Magnesium, an alkaline earth metal belonging to Group 2, can penetrate the lithium-ion crystal layer under high-temperature calcination, acting as a support structure to mitigate lithium layer collapse during periods of high lithium delithiation in the cathode material. The niobium-oxygen bond energy formed by the transition metal niobium is higher than that between nickel, cobalt, and manganese and oxygen, thus mitigating oxygen evolution in the cathode under high lithium delithiation conditions. Phosphate ions can form a good coating layer on the cathode material surface. Phosphates, with their more stable properties compared to the transition metals on the surface of ternary cathode materials, can mitigate electrolyte attack and the migration of transition metals on the cathode material surface under high lithium delithiation conditions, thereby reducing the failure of ternary cathode materials. These three factors work together to improve the lifespan of ternary cathode materials under high voltage. Attached Figure Description

[0011] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0012] Figure 1 Here is a SEM image of the high-nickel ternary cathode material prepared in Example 1; Figure 2 This is a SEM image of the high-nickel ternary cathode material prepared in Comparative Example 1. Detailed Implementation

[0013] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0014] High-nickel ternary cathode materials suffer from surface instability, transition metal dissolution, electrolyte corrosion, and structural damage and oxygen evolution under high voltage. These defects lead to poor lifespan and cycle performance under high voltage. Specifically, the Ni content in high-nickel materials... 2+ The content of Ni (radius 0.69 Å) is very high. 2+ The radius and Li + (Radius 0.76 Å) is close, during synthesis and cycling, especially during deep delithiation (high voltage charging), Ni 2+ Easier to migrate to Li + The 3a site (i.e., the position of Li in the rock salt structure) causes severe cation mixing. This mixing disrupts the regularity of the layered structure and hinders Li... + The diffusion channels are opened, and lattice stress is introduced. During deep delithiation, high-nickel materials undergo a phase transition from the original hexagonal layered structure (H1) to a monoclinic phase (M), and then to a hexagonal phase (H2 / H3). The H2 to H3 phase transition (corresponding to a sharp contraction of the c-axis) generates huge anisotropic stresses within the grains. The repeated accumulation and release of this stress is the main reason for the formation of microcracks and even grain fracture within the grains. Fractured grains expose new surfaces, accelerating side reactions.

[0015] High-nickel materials often exhibit nickel-rich rock salt phases (NiO-like) or residual lithium compounds (such as Li₂CO₃, LiOH) on their surfaces. These surface species possess extremely high oxidation activity under high voltage. Under high voltage, exposed high-oxidation-state transition metal ions (especially Ni) 4+ This intense surface reaction strongly catalyzes the oxidative decomposition of the electrolyte (solvent and lithium salt) on the positive electrode surface. This leads to: continuous electrolyte consumption, forming a thick and highly impedance CEI film; gas production (CO2, CO, O2, etc.), causing battery swelling; and the dissolution of transition metal ions (especially Mn and Co), which migrate to the negative electrode and damage the SEI film, resulting in loss of active lithium and capacity decay. The severe surface side reactions gradually reduce the layered structure of the surface to an electrochemically inert spinel phase or even a rock salt phase, hindering Li⁺ transport and increasing interfacial impedance.

[0016] During deep delithiation, the nickel in the material is mainly in a high valence state (Ni). 4+ Ni 4+ It possesses strong oxidizing power, and its 3d orbitals are highly hybridized with O 2p orbitals. This leads to lattice oxygen (O 2- The electron cloud density of oxygen atoms decreases, making oxygen atoms unstable; Trace amounts of acidic substances (such as HF) or nucleophilic solvent molecules produced by electrolyte decomposition can attack the already unstable lattice oxygen (O₂). -Species). This attack leads to the formation of Oo bonds (oxygen evolution reaction: 2O). - → O2 + 2e - ) or react directly with protons to produce water (2O) - + 2H + → H2O + 1 / 2O2); After oxygen evolution, oxygen vacancies are left in the material. Oxygen vacancies further promote the migration and reduction of transition metal ions (especially Ni) (e.g., Ni 4+ → Ni 2+ This exacerbates cation mixing and structural collapse from the surface to the bulk phase.

[0017] To address the above problems, this invention provides a method for preparing a high-nickel ternary cathode material, comprising the following steps: The ternary cathode precursor nickel cobalt manganese oxide, lithium source, magnesium source and niobium source are mixed and ground in proportion, and then calcined in an oxygen atmosphere to obtain a ternary cathode material intermediate. The mass ratio of magnesium to lithium nickel cobalt manganese oxide is 1000-2000ppm, and the mass ratio of niobium to lithium nickel cobalt manganese oxide is 1500-2500ppm. The ternary cathode material intermediate is added to a phosphate solution or a phosphoric acid solution, stirred and dispersed thoroughly, and then the solution is dried to obtain a solid material. The dried solid material is calcined at 500-700℃ for 6-10 hours in an oxygen atmosphere to obtain high-nickel ternary cathode material.

[0018] By co-doping with niobium and magnesium, the internal structure of high-nickel ternary cathode materials is optimized. Magnesium provides layer support for the lithium layer, while niobium-oxygen bonds enhance the binding of oxygen atoms, thereby improving the stability of the internal structure of the high-nickel ternary cathode material under higher voltage windows. Simultaneously, phosphate coating is applied to the surface of the high-nickel ternary cathode material, fully utilizing the high voltage stability characteristics of phosphate to improve the structural stability of the surface. This three-pronged approach, addressing both internal and external factors, ultimately improves the cycle life and performance of the high-nickel ternary cathode material under high voltage windows.

[0019] The specific analysis is as follows: Magnesium doping is employed, Mg... 2+ Priority occupation of Li + Sites that form a "pillar effect"; Mg 2+ The supporting layered structure reduces c-axis contraction during deep delithiation and suppresses microcracks in particles.

[0020] When niobium is doped, strong Nb-O bonds are formed with high bond energies, which helps stabilize the oxygen framework, suppress oxygen evolution, and reduce Ni content. 3+ / Ni 4+ Oxidative activity; Nb 5+ It can occupy oxygen vacancies and block the chain reaction of structural collapse.

[0021] Phosphoric acid solution or phosphate solution reacts with residual lithium (Li2CO3 / LiOH) on the material surface to form a Li3PO4 or LiMPO4 (M = transition metal) coating layer. Calcination at 500-700℃ crystallizes the coating layer, forming a dense film. This dense film effectively isolates the electrolyte from the highly active Ni. 4+ Surface contact reduces the solubility of transition metals; it also consumes residual lithium on the surface, reducing electrolyte corrosion. Furthermore, Li3PO4 is a lithium... + Conductor (ionic conductivity ~10) -8 (S / cm) can maintain the efficiency of interfacial ion transport.

[0022] Research has shown that the synergistic effect of magnesium-niobium co-doping and surface-coated phosphate layer can effectively solve the problems of instability, transition metal dissolution, electrolyte corrosion, structural damage and oxygen evolution under high voltage in high-nickel ternary cathode materials, which lead to poor lifespan and poor cycle performance under high voltage.

[0023] In some embodiments, the ternary cathode precursor nickel-cobalt-manganese oxide is Ni x Co y Mn 1-x-y O2, 0.7<x<1, 0.02<y<0.3, x+y<1.

[0024] In some embodiments, the lithium source is selected from at least one of lithium carbonate, lithium hydroxide, lithium oxalate, and lithium nitrate.

[0025] Preferably, the lithium source is lithium hydroxide.

[0026] Preferably, the molar ratio of lithium to the total amount of nickel, cobalt, and manganese is 1.03-1.06:1.

[0027] In some embodiments, the magnesium source is selected from at least one of nano magnesium oxide, nano magnesium carbonate, nano magnesium hydroxide, or magnesium nitrate, preferably nano magnesium oxide.

[0028] In some embodiments, the niobium source is selected from at least one of nano-niobium oxide or niobium nitrate, preferably nano-niobium oxide.

[0029] In some embodiments, the calcination temperature under an oxygen atmosphere is 700-900°C, and the calcination time is 10-15 hours.

[0030] In some embodiments, the method further includes the steps of crushing, sieving, and demagnetizing the ternary cathode material intermediate.

[0031] In some embodiments, the mass ratio of phosphate to ternary cathode material intermediate in the phosphate solution or phosphoric acid solution is 2000-4000 ppm.

[0032] Preferably, the phosphate is ammonium hydrogen phosphate or / and ammonium dihydrogen phosphate, more preferably ammonium hydrogen phosphate.

[0033] In some embodiments, the liquid feed is dried by spray drying.

[0034] Secondly, the present invention provides a high-nickel ternary cathode material, which is prepared by the aforementioned preparation method.

[0035] Thirdly, the present invention provides a battery in which the active material on the positive electrode plate is the high-nickel ternary positive electrode material.

[0036] The present invention will be further described below with reference to the embodiments.

[0037] Example 1 A method for preparing a high-nickel ternary cathode material includes the following steps: (1) Weigh out the ternary cathode precursor nickel cobalt manganese oxide Ni 0.9 Co 0.05 Mn 0.05 O2, lithium hydroxide, nano magnesium oxide and nano niobium oxide, wherein the molar ratio of lithium to the total amount of nickel, cobalt and manganese is 1.03, the mass ratio of magnesium to lithium nickel cobalt manganese oxide is 2000 ppm, and the mass ratio of niobium to lithium nickel cobalt manganese oxide is 1500 ppm. (2) Pour all the above materials into a high-speed ball mill for grinding and mixing; (3) The mixed materials are calcined at 900°C for 10 hours in an oxygen atmosphere. Then the calcined materials are crushed, sieved and demagnetized to obtain a ternary cathode material intermediate. (4) Prepare a 0.02 mol / L ammonium hydrogen phosphate solution; (5) Pour the ternary cathode material intermediate obtained in step (3) into a 0.02 mol / L ammonium hydrogen phosphate solution and stir to disperse it. The mass ratio of phosphate ions to ternary cathode material intermediate is 2000 ppm. (6) The liquid obtained in step (5) is dried by spray drying; (7) The dried material in step (6) is calcined at 600°C for 8 hours in an oxygen atmosphere. Then the calcined material is crushed, sieved and demagnetized to obtain the high-nickel ternary cathode material.

[0038] Example 2 A method for preparing a high-nickel ternary cathode material includes the following steps: (1) Weigh out the ternary cathode precursor nickel cobalt manganese oxide Ni 0.9 Co 0.05 Mn 0.05 O2, lithium hydroxide, nano magnesium oxide, and nano niobium oxide; wherein, the molar ratio of lithium to the total amount of nickel, cobalt, and manganese is 1.04, the mass ratio of magnesium to lithium nickel cobalt manganese oxide is 1000 ppm, and the mass ratio of niobium to lithium nickel cobalt manganese oxide is 2500 ppm. (2) Pour all the above materials into a high-speed ball mill for grinding and mixing; (3) The mixed materials are calcined at 800°C for 12 hours in an oxygen atmosphere. Then the calcined materials are crushed, sieved and demagnetized to obtain a ternary cathode material intermediate. (4) Prepare a 0.02 mol / L ammonium dihydrogen phosphate solution; (5) Pour the ternary cathode material intermediate obtained in step (3) into a 0.02 mol / L ammonium dihydrogen phosphate solution and stir to disperse it. The mass ratio of phosphate ions to ternary cathode material intermediate is 3000 ppm. (6) The liquid obtained in step (5) is dried by spray drying; (7) The dried material in step (6) is calcined at 500°C for 10 hours in an oxygen atmosphere. Then the calcined material is crushed, sieved and demagnetized to obtain the high-nickel ternary cathode material.

[0039] Example 3 A method for preparing a high-nickel ternary cathode material includes the following steps: (1) Weigh out the ternary cathode precursor nickel cobalt manganese oxide Ni 0.9 Co 0.05 Mn 0.05 O2, lithium hydroxide, nano magnesium oxide, and nano niobium oxide; wherein, the molar ratio of lithium to the total amount of nickel, cobalt, and manganese is 1.04, the mass ratio of magnesium to lithium nickel cobalt manganese oxide is 1500 ppm, and the mass ratio of niobium to lithium nickel cobalt manganese oxide is 2000 ppm. (2) Pour all the above materials into a high-speed ball mill for grinding and mixing; (3) The mixed materials are calcined at 700°C for 15 hours in an oxygen atmosphere. Then the calcined materials are crushed, sieved and demagnetized to obtain a ternary cathode material intermediate. (4) Prepare a phosphoric acid solution with a concentration of 0.02 mol / L; (5) Pour the ternary cathode material intermediate obtained in step (3) into a phosphoric acid solution with a concentration of 0.02 mol / L and stir and disperse it thoroughly. The mass ratio of phosphate ions to ternary cathode material intermediate is 4000 ppm. (6) The liquid obtained in step (5) is dried by spray drying; (7) The dried material in step (6) is calcined at 700°C for 6 hours in an oxygen atmosphere. Then, the calcined material is crushed, sieved and demagnetized to obtain the high-nickel ternary cathode material.

[0040] Example 4 The difference from Example 1 is that only the ammonium hydrogen phosphate solution in steps (4) and (5) is replaced with ammonium dihydrogen phosphate solution, and everything else is the same as in Example 1.

[0041] Example 5 The difference from Example 1 is that only the ammonium hydrogen phosphate solution in steps (4) and (5) is replaced with a phosphoric acid solution, and everything else is the same as in Example 1.

[0042] Comparative Example 1 The difference from Example 1 is that the ammonium hydrogen phosphate solution in step (4) of Example 1 is replaced with water; all other steps are the same as in Example 1. Specifically, the steps include: (1) Weigh out the ternary cathode precursor nickel cobalt manganese oxide Ni 0.9 Co 0.05 Mn 0.05 O2, lithium hydroxide, nano magnesium oxide and nano niobium oxide, wherein the molar ratio of lithium to the total amount of nickel, cobalt and manganese is 1.03, the mass ratio of magnesium to lithium nickel cobalt manganese oxide is 2000 ppm, and the mass ratio of niobium to lithium nickel cobalt manganese oxide is 1500 ppm. (2) Pour all the above materials into a high-speed ball mill for grinding and mixing; (3) The mixed materials are calcined at 900°C for 10 hours in an oxygen atmosphere. Then the calcined materials are crushed, sieved and demagnetized to obtain a ternary cathode material intermediate. (4) Pour the ternary cathode material intermediate obtained in step (3) into pure water and stir and disperse it thoroughly. The amount of pure water used is the same as the volume of the ammonium hydrogen phosphate solution in Example 1. (5) The liquid obtained in step (4) is dried by spray drying; (6) The dried material in step (5) is calcined at 600°C for 8 hours in an oxygen atmosphere. Then the calcined material is crushed, sieved and demagnetized to obtain the high-nickel ternary cathode material.

[0043] Comparative Example 2 The difference from Example 1 is that nano-magnesium oxide and nano-niobium oxide are omitted in step (1), while everything else is the same as in Example 1. The specific method is as follows: (1) Weigh out the ternary cathode precursor nickel cobalt manganese oxide Ni 0.9 Co 0.05 Mn 0.05 O2 and lithium hydroxide, the ratio of the total molar amount of lithium to nickel, cobalt and manganese is 1.03; (2) Then pour all the above materials into a high-speed ball mill for grinding and mixing; (3) The mixed materials are calcined at 900°C for 10 hours in an oxygen atmosphere. Then the calcined materials are crushed, sieved and demagnetized to obtain a ternary cathode material intermediate. (4) Prepare a 0.02 mol / L ammonium hydrogen phosphate solution; (5) Pour the ternary cathode material intermediate obtained in step (3) into a 0.02 mol / L ammonium hydrogen phosphate solution and stir to disperse it. The mass ratio of phosphate to ternary cathode material intermediate is 2000 ppm.

[0044] (6) The liquid obtained in step (5) is dried by spray drying; (7) The dried material in step (6) is calcined at 600°C for 8 hours in an oxygen atmosphere. Then the calcined material is crushed, sieved and demagnetized to obtain the ternary cathode material product.

[0045] Comparative Example 3 The difference from Example 1 is that in step (1), nano magnesium oxide is replaced with nano niobium oxide in equal amounts, while everything else is the same as in Example 1.

[0046] Comparative Example 4 The difference from Example 1 is that in step (1), the equivalent amount of nano-niobium oxide is omitted and replaced with nano-magnesium oxide, while everything else is the same as in Example 1.

[0047] Comparative Example 5 The difference from Example 1 is that the nano-niobium oxide in step (1) is replaced with nano-yttrium oxide in equal amounts, while all other aspects are the same as in Example 1.

[0048] Comparative Example 6 The difference from Example 1 is as follows: In step (4), 0.5 g of niobium oxalate and 35 mL of high-purity phosphoric acid diluted 100 times were dissolved in a round-bottom flask. The flask was then transferred and fixed on an oil bath reaction system equipped with a reflux condenser. The reaction solution was stirred continuously until a transparent and clear solution was formed. The reaction temperature was then adjusted to 120 °C and the reaction was carried out for 15 h. After the reaction was completed, the system was cooled to room temperature. The obtained product was filtered, washed, and dried to obtain niobium phosphate material. In step (5), 0.3g of the ternary cathode material intermediate obtained in step (3) is mixed with 0.003g of niobium phosphate material prepared in step (4), and then ground thoroughly to achieve uniform mixing. Step (6) is omitted, and step (7) is the same as in Example 1.

[0049] Button battery preparation: The positive electrode materials obtained in Examples 1-5 and Comparative Examples 1-6 were assembled into button batteries, as follows: The positive electrode material, conductive agent (acetylene black) and binder (PVDF) were weighed in a mass ratio of 90:5:5. The weighed positive electrode material and acetylene black were mixed and ground in an agate mortar. After grinding evenly, they were added to N-methylpyrrolidone (NMP) that had fully reacted with PVDF and ground continuously until the slurry became a viscous liquid with a certain fluidity.

[0050] The ground slurry was evenly transferred onto aluminum foil, and the sample was evenly coated with a 300μm thick coater. Then, it was pre-baked in air at 60℃ for 5 hours, and then vacuumed and dried at 90℃ for 12 hours to remove water and organic matter from the coated sample. The electrode sheet was then cut to size for later use to obtain the positive electrode sheet.

[0051] Using lithium foil as the negative electrode and a prepared electrode sheet as the positive electrode, with an electrolyte ratio of EC:DMC=1:1, a coin cell was assembled and charged and discharged using a BTV charge-discharge tester. At 25℃, the lithium-ion battery assembled with the above positive electrode sheet underwent 1C / 1C charge-discharge cycles at an operating voltage of 2.75-4.4V.

[0052] Depend on Figure 1 and Figure 2 It can be seen that the surface of the cathode material particles prepared in Comparative Example 1 is relatively clean, while the surface of the cathode material particles prepared in Example 1 is relatively messy, showing obvious coating marks. At the same time, each cathode material maintains good particle integrity and roundness, indicating that the particles were not significantly damaged during processing.

[0053] Table 1. Performance Comparison of Batteries Assembled Using Cathode Materials Prepared in Examples and Comparative Examples

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-nickel ternary cathode material, characterized in that: The method comprises the following steps: mixing and grinding a ternary positive electrode precursor nickel cobalt manganese oxide, a lithium source, a magnesium source and a niobium source in proportion, and then calcining under an oxygen atmosphere to obtain a ternary positive electrode material intermediate, wherein the mass ratio of magnesium element to lithium nickel cobalt manganese oxide is 1000-2000 ppm, and the mass ratio of niobium element to lithium nickel cobalt manganese oxide is 1500-2500 ppm; adding the ternary positive electrode material intermediate into a phosphate solution or a phosphoric acid solution, fully stirring and dispersing, and then drying the solution to obtain a solid material; calcining the dried solid material under an oxygen atmosphere at 500-700 ℃ for 6-10 h to obtain the high-nickel ternary positive electrode material.

2. The method for preparing the high-nickel ternary cathode material according to claim 1, characterized in that: The ternary positive electrode precursor nickel cobalt manganese oxide is Ni x Co y Mn 1-x-y O2, 0.7 < x < 1, 0.02 < y < 0.3, x + y < 1. 3.The method of claim 1, wherein the method further comprises: adding a lithium source to the mixture; and heating the mixture to a temperature of 800-1000 ℃ for 10-20 hours. The lithium source is at least one selected from lithium carbonate, lithium hydroxide, lithium oxalate and lithium nitrate. Preferably, the lithium source is lithium hydroxide. Preferably, the ratio of lithium to the total amount of nickel, cobalt and manganese in moles is 1.03-1.06:

1. 4.The method of claim 1, wherein the method further comprises: adding a lithium source to the mixture; and heating the mixture to a temperature of 800-1000 ℃ for 10-20 hours. The magnesium source is at least one selected from nano-magnesium oxide, nano-magnesium carbonate, nano-magnesium hydroxide and magnesium nitrate, and is preferably nano-magnesium oxide. The niobium source is at least one selected from nano-niobium oxide and niobium nitrate, and is preferably nano-niobium oxide. 5.The method of claim 1, wherein the method further comprises: adding a lithium source to the mixture; and heating the mixture to a temperature of 800-1000 ℃ for 10-20 hours. The calcining temperature under an oxygen atmosphere is 700-900 ℃, and the calcining time is 10-15 h. 6.The method of claim 1, wherein the method further comprises: adding a lithium source to the mixture; and heating the mixture to a temperature of 800-1000 ℃ for 10-20 hours. The method further comprises the steps of crushing, sieving and demagnetizing the ternary positive electrode material intermediate. 7.The method of claim 1, wherein the method further comprises: adding a lithium source to the mixture of claim 1. In the phosphate solution or the phosphoric acid solution, the mass ratio of phosphate to the ternary positive electrode material intermediate is 2000-4000 ppm. Preferably, the phosphate is ammonium hydrogen phosphate and / or ammonium dihydrogen phosphate, and is preferably ammonium hydrogen phosphate.

8. The method for preparing the high-nickel ternary cathode material according to claim 1, characterized in that: The drying method of the solution is spray drying.

9. A high nickel ternary cathode material, characterized in that: The high-nickel ternary positive electrode material is prepared by the preparation method of any one of claims 1-8.

10. A battery, characterized by: The active material on the positive plate is the high-nickel ternary positive electrode material of claim 9.

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