Metal oxide precursor and preparation method and application thereof

Abstract

The invention discloses a metal oxide precursor and a preparation method and application thereof. The precursor comprises a nickel element, a manganese element and an element M, and the element M comprises one or more of cobalt and aluminum. The preparation method comprises the steps that a mixed metal salt solution with the total metal ion concentration being 2-5 mol / L is prepared; spraying the mixed metal salt solution into a high-temperature pyrolyzing furnace in an aerial fog form, and carrying out a spray pyrolysis reaction; roasting the spray pyrolysis product for 1-4 hours in an oxygen-containing atmosphere, wherein the roasting temperature is 500-700 DEG C; dispersing the roasted product in an acidic aqueous solution, carrying out hydrothermal reaction at 150-250 DEG C for 1-6 hours, and carrying out filter pressing and washing until the conductivity of filtrate is less than 50 [mu] S / cm; and drying the washed product, and carrying out air jet pulverization to obtain the metal oxide precursor. During application, the metal oxide precursor and a lithium source are mixed and sintered to prepare the ternary positive electrode material. Impurities are removed through low-temperature roasting-acidic hydrothermal combination, the structure is optimized, and the performance of the positive electrode is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials for ternary precursor batteries, and particularly relates to a metal oxide precursor, a preparation method thereof, and an application thereof. Background Art

[0002] In the critical period of today's energy transformation, as the core raw material of ternary cathode materials for lithium-ion batteries, the innovation of the preparation technology of ternary oxide precursors is of great significance for improving battery performance and reducing production costs. Spray pyrolysis technology has attracted a large amount of research resources in recent years due to its significant advantages such as no wastewater discharge, low energy consumption, short production process, and high efficiency output. Compared with the traditional co-precipitation ternary precursor technology, spray pyrolysis technology shows obvious competitiveness in manufacturing costs.

[0003] However, this technology still faces severe challenges in practical applications. The products generated during the spray pyrolysis process have problems such as excessive content of impurities such as chlorine and sulfur. The residue of these impurities not only generates harmful gases during the manufacturing process of cathode materials, corrodes the kiln, but also damages the structural integrity and electrochemical performance of ternary cathode materials. In addition, key indicators such as the particle size distribution (such as D50, Dmax), tapped density, and specific surface area of the precursor also have a profound impact on the performance of ternary cathode materials. An unreasonable particle size distribution will make it difficult to achieve close packing of the material during the electrode preparation process, reduce the compaction density of the electrode, and thus affect the energy density of the battery. Insufficient tapped density limits the loading amount of active substances per unit volume, which is also not conducive to improving the energy storage capacity of the battery. And too large or too small specific surface area will affect the interfacial reaction between the material and the electrolyte, and have an adverse impact on the charge and discharge kinetic process of the battery.

[0004] Therefore, how to effectively reduce the impurity content and precisely control various key performance indicators during the preparation of ternary metal oxide precursors by spray pyrolysis technology has become the core problem to be solved urgently in this field. Summary of the Invention

[0005] The purpose of the present invention is to provide a metal oxide precursor, a preparation method thereof, and an application thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A metal oxide precursor contains nickel element, manganese element, and element M; based on the total molar amount of metal elements, the molar proportion of nickel element is 55 - 85 mol%, the molar proportion of manganese element is 0 - 35 mol%, and the molar proportion of element M is 0 - 15 mol%, and the element M includes one or more of cobalt and aluminum.

[0007] In the above solution, the element M may further include zirconium, lanthanum, cerium, magnesium, and calcium.

[0008] Further technical solution: the D50 of the precursor is 1.0 - 4.0 μm, Dmax ≤ 15 μm; chlorine content ≤ 100 ppm, sulfur content ≤ 300 ppm; specific surface area is 6 - 12 m 2 / g, and the tapped density is 1.45 - 2.05 g / cm 3 .

[0009] Further technical solution: when the element M is cobalt, the chemical formula is Ni x Mn y Co z O n ; When the element M is aluminum, the chemical formula is Ni x Mn y Al z O n ; wherein, 0.55 ≤ x ≤ 0.85, 0 ≤ y ≤ 0.35, 0 ≤ z ≤ 0.15, and x + y + z = 1; n = ∑(oxidation state of metal ion × atomic ratio) / 2, that is, n is uniquely determined by the oxidation state combination and charge balance of metal ions.

[0010] Furthermore, the present invention also discloses a preparation method of a metal oxide precursor for preparing the metal oxide precursor; the preparation method includes: Step 1: Dissolve metal salts in deionized water according to a molar ratio, and add a water-soluble dispersant and an additive to prepare a mixed metal salt solution with a total metal ion concentration of 2 - 5 mol / L; Step 2: Spray the mixed metal salt solution in an aerosol form into a high-temperature pyrolysis furnace for spray pyrolysis reaction; Step 3: Calcinate the spray pyrolysis product in an oxygen-containing atmosphere for 1 - 4 h, and the calcination temperature is 500 - 700 °C; Step 4: Disperse the product of Step 3 in an acidic aqueous solution, carry out hydrothermal reaction at 150 - 250 °C for 1 - 6 h, and filter and wash with deionized water until the conductivity of the filtrate < 50 μS / cm; Step 5: Dry the washed product at 120 - 180 °C and obtain the metal oxide precursor by air flow pulverization.

[0011] Further technical solution: in Step 1, the metal salts in the mixed metal salt solution include nickel salt, manganese salt and M salt, and the M salt includes cobalt salt and / or aluminum salt; The nickel salt is selected from at least one of nickel chloride and nickel sulfate; the manganese salt is selected from at least one of chloride and sulfate; the cobalt salt is selected from at least one of cobalt chloride and cobalt sulfate; the aluminum salt is selected from at least one of aluminum chloride and aluminum sulfate.

[0012] In a further technical solution, in step one, the dispersant is at least one of polyacrylic acid, polyvinylpyrrolidone, polymaleic anhydride, carboxymethyl chitosan, and polyethylene glycol, and the addition amount is 0.5-3% of the total mass of the metal salts.

[0013] In a further technical solution, in step one, the additive is at least one of citric acid, ammonium citrate, tartaric acid, and sulfosalicylic acid, and the added molar amount is 1-10% of the total molar number of metal ions.

[0014] In a further technical solution, in step two, the D50 of the droplets after gas atomization of the mixed metal salt solution is 30-200 μm; The top temperature of the high-temperature pyrolysis furnace is 150-350 °C, the pyrolysis temperature in the middle of the furnace is 650-950 °C, and the bottom of the furnace is 450-700 °C. At 150-350 °C at the top of the furnace, evaporation, crystallization, and drying reactions of the atomized droplets occur. At 650 °C - 950 °C in the middle of the furnace, thermal decomposition occurs to form metal oxides. At 450 °C - 700 °C at the bottom of the furnace, high-temperature dechlorination occurs.

[0015] In a further technical solution, in step three, the oxygen-containing atmosphere is air or a nitrogen-oxygen mixture with an oxygen volume ratio of 20-50%.

[0016] In a further technical solution, in step four, the pH value of the acidic aqueous solution at 25 °C is 1.5-6.0, and the acid used is at least one of sulfuric acid, nitric acid, and acetic acid; The hydrothermal reaction is carried out in a hydrothermal reaction kettle. The filling degree of the hydrothermal reaction kettle is 60-80%, the solid-liquid ratio in the hydrothermal impurity removal process is 1:(1-4), and the temperature of the washing water is 50-80 °C.

[0017] Furthermore, the present invention also discloses an application of the metal oxide precursor. The metal oxide precursor is mixed and sintered with a lithium source to prepare a ternary cathode material.

[0018] Regarding the use of "comprising", "including", "having", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0019] Regarding the terms used in this article, unless otherwise specified, they generally have their ordinary meanings in this field, in the context of this case, and in the context of special content. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of this case.

[0020] The working principle and advantages of the present invention are as follows: The present invention provides a preparation method for producing ternary metal oxides with low impurity content by spray pyrolysis. Compared with the prior art, the present invention significantly reduces the impurity content such as chlorine and sulfur in the pyrolysis product and improves the quality of the ternary metal oxides by optimizing the process steps.

[0021] The present invention significantly reduces the residual Cl⁻ and SO4²⁻ in the product through a hydrothermal synergistic impurity removal process of "low-temperature roasting - acidic condition". Specifically, it includes: after spray pyrolysis of the chloride salt solution containing a dispersant / complexing agent, followed by low-temperature roasting and hydrothermal impurity removal treatment with an acidic solution, and the final product has Cl⁻ ≤ 100 ppm and S ≤ 300 ppm.

[0022] In the preparation method of the metal oxide precursor of the present invention, the roasting treatment in step three and the hydrothermal reaction in step four are the core links to achieve low impurity content and improve product quality.

[0023] In the ternary oxide formed by spray pyrolysis, chlorine and sulfur impurities are dissolved in the lattice interior in the form of compounds. Through low-temperature roasting in an oxygen-containing atmosphere, the chlorine- and sulfur-containing compounds in the lattice undergo oxidative decomposition reactions with oxygen to generate volatile gases. The relatively low temperature allows only limited migration of the precursor atoms, which can not only repair lattice defects and enhance the structural stability of the particles, but also avoid excessive sintering caused by high temperature, thereby preventing the reduction of the particle specific surface area and activity. This low-temperature roasting process precisely targets the impurities in the lattice, efficiently removes chlorine and sulfur while maintaining the activity of the precursor, and at the same time reduces energy consumption and costs. In addition, the loose and porous structure formed after roasting is conducive to the penetration of the hydrothermal solution in step four, further improving the impurity removal efficiency and laying a high-quality raw material foundation for the preparation of high-performance cathode materials.

[0024] After low-temperature calcination, some chlorine and sulfur impurities are still attached to the surface of the precursor. During the hydrothermal process, the high-temperature and high-pressure acidic aqueous solution significantly increases the ion activity, and the hydrogen ions in the solution fully react with the chlorine-containing and sulfur compounds on the surface of the precursor to convert them into soluble substances. At the same time, the high-temperature and high-pressure environment greatly enhances the penetration ability of the acidic solution, allowing it to penetrate deep into the precursor particles. The chlorine and sulfur impurities originally wrapped inside the particles gradually detach under the erosion and dissolution of the acidic solution, and diffuse to the external solution through the microchannels formed by the hydrothermal effect, realizing the transfer from the inside of the particles to the external solution, achieving the purpose of deep impurity removal. This process effectively solves the problem that traditional methods are difficult to remove impurities inside the precursor, and greatly reduces the residual amount of chlorine and sulfur. This deep impurity removal method not only improves the purity of the precursor, but also avoids the problem of decreased performance of the positive electrode material due to residual impurities. In addition, the improvement of the particle structure by the hydrothermal process further optimizes the processing performance of the precursor, ensures the efficient sintering process of the subsequent positive electrode material, and reduces production costs.

[0025] Compared with the prior art, the preparation method of the present invention has reliable process, simple operation and is easy for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Attached Figure 1 This is a scanning electron microscope image of the spray-pyrolyzed oxide precursor of Example 1 of the present invention; Attached Figure 2 This is a scanning electron microscope image of the spray-pyrolyzed oxide precursor of Comparative Example 1 of the present invention; Attached Figure 3 The particle size distribution diagram of the oxides obtained in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: The present invention will be clearly described below with drawings and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. Example

[0029] 1. Preparation of mixed solution: Weigh nickel chloride, manganese chloride and cobalt chloride, dissolve them in deionized water according to the molar ratio of nickel, manganese and cobalt x:y:z = 0.6:0.3:0.1, and prepare a mixed metal salt solution with a total metal ion concentration of 3 mol / L.

[0030] Add polyethylene glycol accounting for 1% of the total mass of the metal salt as a water-soluble dispersant, and add ammonium citrate with a total molar number of metal ions of 0.1. Stir evenly to fully dissolve and mix all components. 2. Spray pyrolysis: Use an air atomization device to atomize the above mixed metal salt solution and spray it into a high-temperature pyrolysis furnace. The temperature at the top of the pyrolysis furnace is set at 250 °C, the pyrolysis temperature in the furnace is 800 °C, and the temperature at the bottom of the furnace is 550 °C.

[0031] 3. Calcination: Place the product obtained by spray pyrolysis in a calcination furnace under an air atmosphere and calcine it at 600 °C for 1 hour.

[0032] 4. Hydrothermal impurity removal: Disperse the calcined product in a sulfuric acid solution with a pH value of 4.0. Control the filling degree of the hydrothermal reaction kettle at 65%, and set the solid-liquid ratio to 1:1. Place the reaction kettle in an environment at 180 °C for hydrothermal reaction for 2 hours.

[0033] After the reaction, perform pressure filtration to separate the solid product and the solution. Wash the solid product after pressure filtration with deionized water at 60 °C multiple times until the conductivity of the filtrate < 50 μS / cm.

[0034] 5. Post-treatment: Then dry the washed product at 150 °C, and finally obtain a metal oxide precursor through air flow pulverization, with the chemical formula Ni 0.6 Mn 0.3 Co 0.1 O 3.4 / 3 . Example

[0035] 1. Preparation of mixed solution: Weigh nickel chloride, manganese chloride, and cobalt chloride, and dissolve them in deionized water according to the molar ratio of nickel, manganese, and cobalt x:y:z = 0.70:0.22:0.08 to prepare a mixed metal salt solution with a total metal ion concentration of 3.5 mol / L.

[0036] Add polymaleic anhydride accounting for 1% of the total mass of the metal salt as a water-soluble dispersant, and add tartaric acid with a total molar number of 0.1. Stir evenly to fully dissolve and mix all components. 2. Spray pyrolysis: Use an air atomization device to atomize the above mixed metal salt solution and spray it into a high-temperature pyrolysis furnace. The temperature at the top of the pyrolysis furnace is 300 °C, the pyrolysis temperature in the furnace is 850 °C, and the temperature at the bottom of the furnace is 600 °C.

[0037] 3. Calcination: Place the product obtained by spray pyrolysis in a calcination furnace under an air atmosphere and calcine it at 600 °C for 2 hours. 4. Hydrothermal impurity removal: Disperse the calcined product in a sulfuric acid solution with a pH value of 4.0. Set the filling degree of the hydrothermal reaction kettle to 60% and the solid-liquid ratio to 1:2. Conduct a hydrothermal reaction at 200 °C for 4 hours. After the impurity removal process is completed, perform pressure filtration, and wash the product after pressure filtration with deionized water at 60 °C until the conductivity of the filtrate < 50 μS / cm.

[0038] 5. Post-treatment: Dry the pressure-filtered product at 160 °C, and finally conduct air jet milling to obtain a metal oxide precursor with the chemical formula Ni 0.70 Mn 0.22 Co 0.08 O 1.1 。 Example

[0039] 1. Preparation of mixed solution: Weigh nickel sulfate, manganese sulfate, and cobalt sulfate, and dissolve them in deionized water according to the molar ratio of nickel, manganese, and cobalt x:y:z = 0.65:0.25:0.10 to prepare a mixed metal salt solution with a total metal ion concentration of 2.2 mol / L.

[0040] Add 1% of carboxymethyl chitosan by mass of the total metal salt as a water-soluble dispersant, and add sulfosalicylic acid with a total molar amount of 0.1. Stir evenly to fully dissolve and mix all components. 2. Spray pyrolysis: Use an air atomization device to atomize and spray the above mixed metal salt solution into a high-temperature pyrolysis furnace. The top temperature of the pyrolysis furnace is 300 °C, the pyrolysis temperature in the furnace is 920 °C, and the bottom temperature of the furnace is 650 °C.

[0041] 3. Calcination: Place the product obtained by spray pyrolysis in a calcination furnace under an air atmosphere and calcine at 650 °C for 2 hours. 4. Hydrothermal impurity removal: Disperse the calcined product in a nitric acid solution with a pH value of 3.0. Set the filling degree of the hydrothermal reaction kettle to 60% and the solid-liquid ratio to 1:2. Conduct a hydrothermal reaction at 220 °C for 4 hours. After the impurity removal process is completed, perform pressure filtration, and wash the product after pressure filtration with deionized water at 60 °C until the conductivity of the filtrate < 50 μS / cm.

[0042] 5. Post-treatment: Dry the pressure-filtered product at 160 °C, and finally conduct air jet milling to obtain a metal oxide precursor with the chemical formula Ni 0.65 Mn 0.25 Co 0.10 O 3.35 / 3 。

[0043] Comparative Example 1 1. Preparation of mixed solution: Similar to Example 1, a mixed metal salt solution with a total metal ion concentration of 3 mol / L and a molar ratio of nickel, manganese, and cobalt of 0.6:0.3:0.1 was prepared. Polyethylene glycol accounting for 1% of the total mass of the metal salts was added as a water-soluble dispersant, and ammonium citrate with a total molar number of metal ions of 0.1 was added. After stirring evenly, all components were fully dissolved and mixed. 2. Spray pyrolysis: Spray pyrolysis was carried out under the same gas atomization conditions and pyrolysis furnace temperature settings as in Example 1 to obtain the primary product of the metal oxide precursor.

[0044] 3. Post-treatment: The spray pyrolysis product was directly subjected to airflow pulverization to obtain the metal oxide precursor with the chemical formula Ni 0.6 Mn 0.3 Co 0.1 O 3.4 / 3 。

[0045] Comparative Example 2 1. Preparation of mixed solution: Similar to Example 2, a mixed metal salt solution with a total metal ion concentration of 3 mol / L and a molar ratio of nickel, manganese, and cobalt of 0.7:0.2:0.1 was prepared. Polymaleic anhydride accounting for 1% of the total mass of the metal salts was added as a water-soluble dispersant, and tartaric acid with a total molar number of 0.1 was added. After stirring evenly, all components were fully dissolved and mixed. 2. Spray pyrolysis: Spray pyrolysis was carried out under the same gas atomization conditions and pyrolysis furnace temperature settings as in Example 2 to obtain the primary product of the metal oxide precursor.

[0046] 3. Calcination: The product obtained by spray pyrolysis was placed in a calcination furnace under an air atmosphere and calcined at 450 °C for 2 hours.

[0047] 4. Hydrothermal impurity removal: The calcined product was dispersed in a sulfuric acid solution with a pH value of 4.0, and the filling degree of the hydrothermal reaction kettle was controlled at 65%, and the solid-liquid ratio was set at 1:1. The reaction kettle was placed in an environment at 120 °C for hydrothermal reaction for 2 hours. After the reaction, pressure filtration was carried out to separate the solid product and the solution. The solid product after pressure filtration was washed repeatedly with deionized water at 60 °C until the conductivity of the filtrate < 50 μS / cm.

[0048] 5. Post-treatment: The washed product was dried at 150 °C and finally pulverized by airflow to obtain the metal oxide precursor with the chemical formula Ni 0.70 Mn 0.22 Co 0.08 O 1.1 。

[0049] The metal oxides prepared in the above Examples 1-2 and Comparative Examples 1-2 were respectively tested and characterized, and the physical and chemical data are shown in Table 1: Table 1 Physical and Chemical Data of Metal Oxides

[0050] Mix the metal oxides obtained in the above Examples 1 - 3 and Comparative Examples 1 - 2 with a lithium source and sinter them to obtain a ternary cathode material.

[0051] Mix the cathode material, a conductive agent, and a binder PVDF into a slurry according to a mass ratio of 96:2:2, coat it on an aluminum foil to make a positive electrode sheet, use a metallic lithium sheet as the negative electrode sheet, assemble it into a coin cell, charge and discharge it at a cycle voltage of 3.0 - 4.45 V, test its first - cycle charge - discharge capacity at a current density of 0.1 C, and test its capacity retention rate at 50 cycles with a current density of 1 C.

[0052] Table 2 Performance of the cathode material

[0053] Comparing the data of each example in Table 1, it can be seen that: In Examples 1 - 3, due to the adoption of the low - temperature roasting and acidic hydrothermal synergistic impurity removal process, the chlorine and sulfur impurities in the lattice and on the particle surface are effectively removed. At the same time, through crystal reconstruction, Dmax is reduced, and the particle size distribution and microstructure are optimized. Therefore, the precursor has a low impurity content (Cl ≤ 100 ppm, S ≤ 300 ppm), the specific surface area (BET) and the tapped density (TD) are in the ideal range, and the ternary cathode material prepared shows excellent electrochemical performance. The first - discharge specific capacity at 0.1 C exceeds 200 mAh / g, and the capacity retention rate at 50 cycles with a current density of 1 C reaches more than 97%.

[0054] In Comparative Example 1, roasting and hydrothermal impurity removal treatments were not carried out, and a large amount of chlorine and sulfur impurities remained (Cl reached 897 ppm, S reached 554 ppm), and Dmax was as high as 17.627 μm with uneven particle size distribution, resulting in a first - cycle efficiency of only 89.6% for the cathode material and a capacity retention rate of only 95.6% at 50 cycles with a current density of 1 C. The performance is significantly lower than that of the examples. In addition, although roasting and hydrothermal treatments were carried out in Comparative Example 2, due to the too - low roasting temperature and the unoptimized hydrothermal conditions, the impurity removal was not complete (Cl 289 ppm, S 377 ppm), and Dmax was still relatively large (14.748 μm), which also affected the charge - discharge performance of the cathode material, and the capacity retention rate was only 95.3%.

[0055] In summary, through the core steps of setting low - temperature roasting to remove lattice impurities and crystal reconstruction, and acidic hydrothermal treatment to deeply remove surface impurities, the present invention significantly reduces the contents of impurities such as chlorine and sulfur in the pyrolysis products, optimizes the particle size distribution and structure of the precursor, and then greatly improves the charge - discharge capacity, first - cycle efficiency, and cycle stability of the cathode material, effectively solving the performance defect problems existing in the preparation of ternary precursors by spray pyrolysis technology.

[0056] The above embodiments are only used to illustrate the technical concept and features of the present invention. The purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A metal oxide precursor, characterized in that: Contains nickel, manganese, and element M; Based on the total molar number of metal elements, the molar proportion of nickel element is 55-85 mol%, the molar proportion of manganese element is 0-35 mol%, and the molar proportion of element M is 0-15 mol%. The element M includes one or more of cobalt and aluminum.

2. The metal oxide precursor according to claim 1, characterized in that: The D50 of the precursor is 1.0~4.0μm, Dmax≤15μm; the chlorine content is ≤100ppm, the sulfur content is ≤300ppm; the specific surface area is 6-12m 2 / g, tap density is 1.45~2.05g / cm 3 .

3. The metal oxide precursor according to claim 1 or 2, characterized in that: When the element M is cobalt, the chemical formula is Ni x Mn y Co z O n ; When the element M is aluminum, the chemical formula is Ni x Mn y Al z O n ; Among them, 0.55≤x≤0.85, 0≤y≤0.35, 0≤z≤0.15, x + y + z = 1; n=∑(metal ion oxidation state × atomic ratio) / 2.

4. A method for preparing a metal oxide precursor, characterized in that: Used to prepare the metal oxide precursor according to any one of claims 1 to 3; the preparation method comprises: Step 1: dissolving a metal salt in deionized water at a molar ratio, and adding a water-soluble dispersant and an additive to prepare a mixed metal salt solution with a total metal ion concentration of 2-5 mol / L; Step 2, spraying the mixed metal salt solution into a high-temperature pyrolysis furnace in the form of aerosol to perform a spray pyrolysis reaction; Step 3: calcining the spray pyrolysis product in an oxygen-containing atmosphere for 1-4 hours at a calcination temperature of 500-700°C; Step 4: Disperse the product of step 3 in an acidic aqueous solution, perform hydrothermal reaction at 150-250° C. for 1-6 hours, filter press, and wash with deionized water until the filtrate conductivity is less than 50 μS / cm; Step 5: Dry the washed product at 120-180° C. and grind it by air flow to obtain a metal oxide precursor.

5. The method for preparing a metal oxide precursor according to claim 3, characterized in that: In step 1, the metal salt in the mixed metal salt solution includes nickel salt, manganese salt and M salt, and the M salt includes cobalt salt and / or aluminum salt; The nickel salt is selected from at least one of nickel chloride and nickel sulfate; The manganese salt is selected from at least one of chloride and sulfate; The cobalt salt is selected from at least one of cobalt chloride and cobalt sulfate; The aluminum salt is selected from at least one of aluminum chloride and aluminum sulfate.

6. The method for preparing a metal oxide precursor according to claim 3, characterized in that: In step 1, the dispersant is at least one of polyacrylic acid, polyvinyl pyrrolidone, polymaleic anhydride, carboxymethyl chitosan, and polyethylene glycol, and the added amount is 0.5-3% of the total mass of the metal salt.

7. The method for preparing a metal oxide precursor according to claim 3, characterized in that: In step 1, the additive is at least one of citric acid, ammonium citrate, tartaric acid, and sulfosalicylic acid, and the added molar amount is 1-10% of the total molar number of metal ions.

8. The method for preparing a metal oxide precursor according to claim 3, characterized in that: In step 2, the droplet D50 of the mixed metal salt solution after atomization is 30-200 μm; The top temperature of the high-temperature pyrolysis furnace is 150-350°C, the pyrolysis temperature in the furnace is 650-950°C, and the bottom temperature is 450-700°C.

9. The method for preparing a metal oxide precursor according to claim 3, characterized in that: In step three, the oxygen-containing atmosphere is air or a nitrogen-oxygen mixture with a volume ratio of 20-50% of oxygen.

10. The method for preparing a metal oxide precursor according to claim 3, characterized in that: In step 4, the pH value of the acidic aqueous solution at 25° C. is 1.5-6.0, and the acid used is at least one of sulfuric acid, nitric acid, and acetic acid; The hydrothermal reaction is carried out in a hydrothermal reactor, the filling degree of the hydrothermal reactor is 60-80%, the solid-liquid ratio of the hydrothermal impurity removal process is 1:(1-4), and the washing water temperature is 50-80°C.

11. An application of a metal oxide precursor, characterized in that: The metal oxide precursor according to any one of claims 1 to 3 is mixed with a lithium source and sintered to obtain a ternary positive electrode material.

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