Lithium-containing composite precursor and preparation method thereof, positive electrode material and battery

Abstract

The invention discloses a lithium-containing composite precursor and a preparation method thereof, a positive electrode material and a battery. The lithium-containing composite precursor is formed by compounding nanocrystallized metal oxide particles, metal hydroxide particles, a lithium salt and an additive, the sintering activity is high, the nanocrystallized metal oxide particles are in close contact with the lithium salt during sintering, the diffusion distance of lithium is short, a liquid phase environment can be provided after the additive is molten, diffusion of lithium is promoted, the sintering time is short, and the lithium-containing composite precursor is prepared. The metal hydroxide has a layered structure similar to that of the target positive electrode material and can be used as a crystal nucleus to promote formation of the layered-structure single crystal positive electrode material, and the sintered single crystal lithium ion positive electrode material has excellent electrical performance; meanwhile, the composite precursor is large in bowl loading amount and low in production cost.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and in particular to a lithium-containing composite precursor and a preparation method thereof, a positive electrode material and a battery. Background Art

[0002] Ternary cathode materials (LiNi x Co y Mn 1−x−y O2) has a high specific capacity and is the mainstream cathode material in the current electric passenger vehicle market, widely used in pure electric vehicles with high range requirements. Currently, battery companies mostly use polycrystalline materials, but they are prone to secondary particle breakage during the cycle process, resulting in rapid battery capacity degradation and affecting the service life of the vehicle. In contrast, single-crystal materials can effectively prevent particle breakage and combine superior safety and cycling performance with high compaction density. They can meet the long battery life and high energy density requirements of new energy vehicles and are an important research and development direction for future ternary materials.

[0003] The preparation of single-crystal ternary cathode materials is typically achieved by uniformly mixing lithium salts with precursor powders and then calcining them at high temperatures in a relatively simple solid-phase process. However, industrially produced precursors are often prepared using a co-precipitation method, resulting in a powder particle size typically greater than 3μm, while the lithium salt particle size is 100-200μm. The raw material mixing scale is limited to the micron level, requiring high sintering temperatures and long sintering times. This, in turn, causes severe lithium-nickel mixing, degrading the material's electrochemical performance and restricting its large-scale application in power batteries. Although reducing the precursor powder particle size (e.g., nano-crystallization) can improve sintering activity and electrochemical performance, small-particle precursors are difficult to prepare and suffer from problems such as low sintering capacity, insufficient production capacity, and high costs, making it difficult to meet the rapidly growing demand for power batteries in the new energy vehicle market.

[0004] Nickel cobalt manganese oxide is prepared by spray pyrolysis of a mixed solution of nickel, cobalt and manganese chloride or nitrate. Although this can reduce the use of precipitants and wastewater treatment costs, its reaction activity with lithium is low, and it still requires high-temperature and long-term sintering, and needs to be crushed to about 1μm before use. It also faces the problems of low filling volume, limited production capacity and high cost, which is not conducive to cost reduction and efficiency improvement of new energy vehicle power batteries.

[0005] In summary, how to significantly reduce the production cost of the precursor while improving its sintering activity, increasing the calcination load and optimizing the overall cost has become the core direction of current technical research in this field, which is of great significance to promoting the upgrading of new energy vehicle power battery technology and the sustainable development of the industry. Summary of the Invention

[0006] The purpose of the present invention is to provide a lithium-containing composite precursor and a preparation method thereof, a positive electrode material and a battery.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: A lithium-containing composite precursor is a secondary particle formed by the accumulation of primary particles. The precursor is composed of a composite of metal oxides, metal hydroxides, lithium salts and additives. The particle size D50 is 5-50μm, and the primary particles are nano-sized and less than 500nm in size.

[0008] A further technical solution is that the metal oxide chemical formula is (Ni x1 Co y1 Mn z1 Al t1 ) a1 M1 b1 O c1 , wherein 0<x1<1, 0<y1<1, 0≤z1<1, 0≤t1<0.1, x1+y1+z1+t1=1, 0.9<a1≤1, 0≤b1<0.1, a1+b1=1, c1 satisfies chemical valence balance, and M1 is a combination of one or more elements selected from the group consisting of calcium, magnesium, aluminum, titanium, zirconium, tungsten, yttrium, strontium, niobium, molybdenum, vanadium, tantalum, boron, and phosphorus; The chemical formula of the metal hydroxide is (Ni x2 Co y2 Mn z2 Al t2 ) a2 M2 b2 (OH) c2 , 0<x2<1, 0<y2<1, 0≤z2<1, 0≤t2<0.1, x2+y2+z2+t2=1, 0.9<a2≤1, 0≤b2<0.1, a2+b2=1, c2 satisfies chemical valence balance, and M2 is a combination of one or more elements selected from the group consisting of calcium, magnesium, aluminum, titanium, zirconium, tungsten, yttrium, strontium, niobium, molybdenum, vanadium, tantalum, boron, and phosphorus; The lithium salt is a combination of one or more of lithium carbonate, lithium bicarbonate, lithium hydroxide, lithium oxide, lithium acetate, lithium nitrate, and lithium oxalate; The additive is a combination of one or more carbonates, oxides, and hydroxides of element M3, where M3 is a combination of one or more elements of calcium, magnesium, aluminum, titanium, zirconium, tungsten, yttrium, strontium, niobium, molybdenum, vanadium, tantalum, boron, or phosphorus.

[0009] In a further technical solution, the ratio of the metal oxide to the total mass of the metal oxide and the metal hydroxide is 0-1:1, the molar ratio of lithium to metal is 0.70-1.50:1, and the ratio of the additive to the total mass of the metal oxide and the metal hydroxide is 0-0.1:1.

[0010] Furthermore, the present invention also includes a method for preparing a lithium-containing composite precursor, comprising: S1. Preparation of Metal Oxides Dissolving and mixing a first nickel salt, a first cobalt salt, a first manganese salt and / or a first aluminum salt, and an M1 salt to obtain a first metal liquid with a metal concentration of 0.5 to 5.0 mol / L; spray pyrolysis of the first metal liquid to obtain a metal oxide; S2. Preparation of Metal Hydroxides Mixing and dissolving a second nickel salt, a second cobalt salt, a second manganese salt and / or a second aluminum salt to obtain a second metal liquid having a metal concentration of 1.0 to 2.5 mol / L; dissolving the M2 salt to obtain an M2 salt solution; Adding pure water, complexing agent and precipitant into the reaction kettle as reaction bottom liquid; The second metal solution, the complexing agent, the precipitant and the M2 salt solution are continuously added to the reactor simultaneously, and the temperature, the complexing agent concentration and the solution pH in the reactor are maintained to perform a coprecipitation reaction; After the reaction stops, the product is filtered, washed, and dried to obtain a metal hydroxide; S3, crushing the metal oxide and the metal hydroxide, adding them to pure water with lithium salt and additives, grinding them into nanoparticles with D50 less than 1 μm, and then spray heat treatment to obtain the lithium-containing composite precursor.

[0011] In a further technical solution, in S1, the first nickel salt is a combination of one or more of nickel nitrate, nickel chloride, and nickel acetate; The first cobalt salt is a combination of one or more of cobalt nitrate, cobalt chloride, and cobalt acetate; The first manganese salt is a combination of one or more of manganese nitrate, manganese chloride, and manganese acetate; The first aluminum salt is a combination of one or more of aluminum nitrate, aluminum chloride, and aluminum acetate; The M1 salt is a combination of one or more of calcium salt, magnesium salt, titanium salt, zirconium salt, tungsten salt, yttrium salt, strontium salt, niobium salt, molybdenum salt, vanadium salt, tantalum salt, borate or phosphate.

[0012] In a further technical solution, in S2, the second nickel salt is a combination of one or more of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate; The second cobalt salt is a combination of one or more of cobalt sulfate, cobalt chloride, cobalt nitrate, and cobalt acetate; The second manganese salt is a combination of one or more of manganese sulfate, manganese chloride, manganese nitrate, and manganese acetate; The second aluminum salt is a combination of one or more of aluminum sulfate, aluminum chloride, aluminum nitrate, and aluminum acetate; The M2 salt is a combination of one or more of calcium salts, magnesium salts, aluminum salts, titanium salts, zirconium salts, borates, tungsten salts, yttrium salts, strontium salts, niobium salts, molybdenum salts, vanadium salts, tantalum salts, borates or phosphates; The complexing agent is a combination of one or more of ammonia water, ammonium sulfate, ammonium chloride, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, and ammonium acetate; The precipitant is a combination of one or more of sodium hydroxide and potassium hydroxide.

[0013] In a further technical solution, in S1, the atomization method of the spray pyrolysis is one of pressure spray, centrifugal spray, and ultrasonic spray, the droplet size is less than 100 μm, and the pyrolysis temperature is 600-1200°C; In S2, the reaction temperature is 40-75°C, the complexing agent concentration is 0.2-0.5 mol / L, and the pH range is 10.60-12.60; In S3, the atomization method of the spray pyrolysis is one of pressure spray, centrifugal spray, and ultrasonic spray, the droplet size is less than 100 μm, and the heat treatment temperature is 150~900°C.

[0014] Furthermore, the present invention also discloses a lithium-ion battery positive electrode material, which is obtained by mixing the lithium-containing composite precursor with a lithium source, calcining it under high temperature and oxygen atmosphere, and crushing it to obtain a single crystal lithium-ion positive electrode material, the chemical formula of which is Li(Ni x Co y Mn z Al t ) a M b O c , wherein 0<x<1, 0<y<1, 0≤z<1, 0≤t<0.1, x+y+z+t=1, 0.9<a≤1, 0≤b<0.1, a+b=1, c satisfies chemical valence balance, M is a combination of one or more elements of calcium, magnesium, aluminum, titanium, zirconium, tungsten, yttrium, strontium, niobium, molybdenum, vanadium, tantalum, boron or phosphorus, and the particle size D50 of the positive electrode material is 3~5μm.

[0015] In a further technical solution, the lithium source is a combination of one or more of lithium carbonate, lithium bicarbonate, and lithium hydroxide; the calcination temperature is 650°C to 1100°C, the oxygen concentration of the oxygen atmosphere is 60% to 100%, and the calcination time is 8 to 16 hours.

[0016] Furthermore, the present invention also discloses a lithium-ion battery, comprising a positive electrode plate, wherein the positive electrode plate is made of the lithium-ion battery positive electrode material.

[0017] The terms “include”, “including”, “have”, etc. used in this document are open-ended terms, meaning including but not limited to.

[0018] Unless otherwise noted, the terms used herein generally have their ordinary meanings in the art, in the context of this application, and in the specific context. Certain terms used to describe this application are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of this application.

[0019] The working principle and advantages of the present invention are as follows: Compared to existing technologies, this invention uses low-cost metal oxides (spray pyrolysis), metal hydroxides (coprecipitation), lithium salts, and additives, and prepares a lithium-containing composite precursor through nano-sizing combined with spray pyrolysis. This precursor has the following advantages: 1. High sintering activity: Nano-sized metal oxides and metal hydroxides have excellent sintering reaction activity, and the nano-metal particles are in close contact with lithium salts, which significantly shortens the diffusion distance of lithium.

[0020] 2. Low-temperature sintering: Additives can melt at low temperatures to form a liquid phase environment, promote the diffusion of lithium, and thus reduce the sintering temperature.

[0021] 3. Structural guidance: Metal hydroxides have similar layered structures to the target cathode materials and can serve as crystal nuclei to induce the formation of layered single crystal cathode materials, ultimately obtaining single crystal materials with excellent electrical properties.

[0022] 4. Process economy: The lithium-containing composite precursor has a large particle size and a high calcination loading capacity, which effectively reduces the sintering cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Attachment Figure 1 This is an electron microscope image of the lithium-containing composite precursor prepared in Example 1 of the present invention; Attachment Figure 2 This is an electron microscope image of the single crystal positive electrode material prepared in Example 1 of the present invention; Attachment Figure 3 This is an electron microscope image of the metal hydroxide prepared in Comparative Example 1 of the present invention; Attachment Figure 4 This is an electron microscope image of the metal oxide prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments: The present invention will be clearly illustrated below with drawings and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art will be able to make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0025] The terms used herein are for describing specific embodiments only and are not intended to be limiting of the present invention. Singular forms such as "a," "the," "this," "this," and "the" as used herein also include plural forms.

[0026] Example 1: comprising the following steps: S1. Preparation of Metal Oxides a. Prepare a 2.0 mol / L first metal solution of nickel chloride, cobalt chloride, manganese chloride, and magnesium chloride, wherein the molar ratio of nickel, cobalt, and manganese is 65:15:20, and the total molar ratio of nickel, cobalt, and manganese to the molar ratio of magnesium is 99:1. The M1 salt is magnesium chloride.

[0027] b. The first metal liquid is subjected to centrifugal spray pyrolysis with a droplet size of 50 μm and a pyrolysis temperature of 800°C to obtain a metal oxide with a particle size of D50 = 10.0 μm, the chemical formula of which is (Ni 0.65 Co 0.15 Mn 0.20 ) 0.99 Mg 0.01 O 2.4 , the primary particle size is 200~300nm; S2. Preparation of Metal Hydroxides a. Prepare a 2.0 mol / L second metal solution by mixing nickel chloride, cobalt chloride, and manganese chloride in a molar ratio of nickel, cobalt, and manganese of 65:15:20; and dissolve magnesium chloride to obtain a 1.0 mol / L salt solution; b. Add pure water, ammonia water and 32% concentration of NaOH into the reactor as the reaction base liquid; c. The second metal liquid, magnesium chloride solution, ammonia water, and 32% NaOH are co-precipitated at 50°C and pH 11.5. The M2 salt solution is magnesium chloride solution.

[0028] d. After the reaction stops, the product is filtered, washed, and dried to obtain a metal hydroxide having the chemical formula (Ni 0.65 Co 0.15 Mn 0.20 ) 0.99 Mg 0.01 (OH)2, particle size D50 = 3.8 μm; S3, crushing the metal oxide and the metal hydroxide to a particle size of 1.0 μm after crushing, adding them to pure water with a lithium salt (lithium carbonate) and an additive (boric acid) for grinding; the ratio of the metal oxide to the total mass of the metal oxide and the metal hydroxide is 0.8:1, the molar ratio of lithium to metal is 1.06, and the ratio of the additive to the total mass of the metal oxide and the metal hydroxide is 0.005:1. After grinding into nanoparticles with D50=0.5 μm, spray heat treatment is performed, the droplet particle size is 60 μm, and the heat treatment temperature is 200°C to obtain a lithium-containing composite precursor, wherein Li:(Ni+Co+Mn)=0.90 and the particle size D50=10.4 μm; S4, the lithium-containing composite precursor and lithium carbonate were mixed according to Li: (Ni + Co + Mn) = 1.06, and then sintered at 900 ° C in an oxygen atmosphere for 11 hours, and then crushed to obtain a single crystal lithium-ion battery positive electrode material. The chemical formula is Li (Ni 0.65 Co 0.15 Mn 0.20 ) 0.99 Mg 0.01 O2, particle size D50=4.2μm.

[0029] Example 2: comprising the following steps: S1. Preparation of Metal Oxides a. preparing a 2.0 mol / L first metal liquid by mixing nickel chloride, cobalt chloride and manganese chloride in a molar ratio of nickel, cobalt and manganese of 65:15:20; b. The first metal liquid is subjected to centrifugal spray pyrolysis with a droplet size of 50 μm and a pyrolysis temperature of 800°C to obtain a metal oxide with a particle size of D50 = 10.5 μm, with a chemical formula of Ni 0.65 Co 0.15 Mn 0.20 O 2.4 , the primary particle size is 200~300nm; S2. Preparation of Metal Hydroxides a. nickel chloride, cobalt chloride, and manganese chloride are mixed in a molar ratio of nickel, cobalt, and manganese of 65:15:20 to form a 2.0 mol / L second metal solution; b. Add pure water, ammonia water and 32% concentration of NaOH into the reactor as the reaction base liquid; c. The second metal liquid, ammonia water, and 32% NaOH were subjected to a coprecipitation reaction at a temperature of 50°C and a pH of 11.5; d. After the reaction stops, the product is filtered, washed, and dried to obtain a metal hydroxide with the chemical formula Ni 0.65 Co 0.15 Mn 0.20 (OH)2, particle size D50 = 3.8 μm; S3, crushing the metal oxide and the metal hydroxide to a particle size of 1.0 μm after crushing, adding them to pure water with a lithium salt (lithium carbonate) and an additive (boric acid) for grinding, wherein the ratio of the metal oxide to the total mass of the metal oxide and the metal hydroxide is 0.9:1, the molar ratio of lithium to metal is 1.06, and the ratio of the additive to the total mass of the metal oxide and the metal hydroxide is 0.005:1. After grinding into nanoparticles with D50=0.5 μm, spray heat treatment is performed, the droplet size is 60 μm, and the heat treatment temperature is 200°C to obtain a lithium-containing composite precursor, wherein Li:(Ni+Co+Mn)=1.06 and the particle size D50=10.8 μm; S4, sintering the lithium-containing composite precursor at 890 ° C in an oxygen atmosphere for 11 hours, and then crushing it to obtain a single crystal lithium-ion battery positive electrode material with the chemical formula of LiNi 0.65 Co 0.15 Mn 0.20 O2, particle size D50=4.2μm.

[0030] Comparative Example 1: comprising the following steps: S1. Nickel chloride, cobalt chloride, and manganese chloride are prepared into a 2.0 mol / L second metal solution at a molar ratio of nickel, cobalt, and manganese of 65:15:20; magnesium chloride is dissolved to obtain a 1.0 mol / L salt solution; S2, adding pure water, complexing agent and precipitant into the reactor as reaction bottom liquid; S3, continuously adding the second metal liquid, magnesium chloride solution, ammonia water, and 32% concentration of NaOH into the reactor, maintaining the temperature in the reactor at 50°C, the ammonia concentration at 0.1 mol / L, and the pH at 11.5, to carry out a coprecipitation reaction; S4. After the reaction stops, the product is filtered, washed, and dried to obtain a metal hydroxide. The chemical formula is (Ni 0.65 Co 0.15 Mn 0.20 ) 0.99 Mg 0.01 (OH)2, particle size D50 = 3.8 μm; S5. Mix metal hydroxide, lithium carbonate, and additive (boric acid), wherein Li:(Ni+Co+Mn)=1.04, and the mass ratio of boric acid to metal hydroxide is 0.005:1; after mixing, sinter at 950°C in an oxygen atmosphere for 18 hours, and then crush to obtain a single crystal lithium ion battery positive electrode material, the chemical formula of which is Li(Ni 0.65 Co 0.15 Mn 0.20 ) 0.99 Mg 0.01 O2, particle size D50 is 4.2μm.

[0031] Comparative Example 2: comprising the following steps: S1, nickel chloride, cobalt chloride, and manganese chloride are prepared into a 2.0 mol / L metal solution at a molar ratio of nickel, cobalt, and manganese of 65:15:20; S2, spray pyrolysis of the metal liquid, with a droplet size of 50 μm and a pyrolysis temperature of 800 ° C, to obtain metal oxides with the chemical formula Ni 0.65 Co 0.15 Mn 0.20 O 2.4 , particle size D50 = 10 μm, primary particles are 200 ~ 300 nm; S3, crushing the metal oxide to obtain small particles of metal oxide, D50 = 1.5 μm; S4. Small-particle metal oxide, lithium carbonate, and additive (boric acid) are mixed, with Li:(Ni+Co+Mn)=1.04, and the mass ratio of boric acid to small-particle metal oxide is 0.005:1. Then, the mixture is sintered at 960°C in an oxygen atmosphere for 18 hours, and the single-crystal lithium-ion battery positive electrode material is obtained after crushing. The chemical formula is LiNi 0.65 Co 0.15 Mn 0.20 O2, particle size D50 is 4.2μm.

[0032] Table 1 Electrical performance test table of single crystal positive electrode materials

[0033] From the above Table 1, combined with the electron microscope images of Example 1 and the two comparative examples, it can be seen that Examples 1 and 2 of the present invention have a large amount of lithium-containing composite precursor, the metal oxides, metal hydroxides, and lithium salts therein are all nanoparticles with high sintering activity. In addition, the metal hydroxide serves as the crystal nucleus, and the sintered single crystal is more rounded and has better electrochemical properties after sintering. However, since the precursor of Comparative Example 1 is small-particle hydroxide particles, the electrochemical performance after sintering is close to that of Example 1, but the amount of the precursor is small and the sintering time is long. The precursor of Comparative Example 2 is a crushed metal oxide with low activity and poor electrochemical performance after sintering. At the same time, the amount of the precursor is small and the production capacity is low.

[0034] In summary, the present invention uses low-cost nano-metal oxide particles and hydroxides, and forms a large-particle, high-activity composite precursor with lithium salts and additives through direct spray heat treatment, which has the advantages of large loading capacity and low sintering cost. The close contact between the nano-metal particles and the lithium salt significantly shortens the diffusion distance of lithium during the sintering process; at the same time, the liquid phase environment formed by the melting of the additive further promotes lithium diffusion, thereby shortening the sintering time. In addition, due to its layered structure similar to that of the target positive electrode material, the metal hydroxide can serve as a crystal nucleus to promote the formation of layered single-crystal positive electrode materials, ultimately enabling the material to obtain better electrochemical properties.

[0035] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A lithium-containing composite precursor, characterized in that: The precursor is a secondary particle formed by the accumulation of primary particles, which is composed of a composite of metal oxides, metal hydroxides, lithium salts and additives. The particle size D50 is 5~50μm, and the primary particles are nano-sized and less than 500nm in size.

2. The lithium-containing composite precursor according to claim 1, characterized in that: The metal oxide chemical formula is (Ni x1 Co y1 Mn z1 Al t1 ) a1 M1 b1 O c1 , wherein 0<x1<1, 0<y1<1, 0≤z1<1, 0≤t1<0.1, x1+y1+z1+t1=1, 0.9<a1≤1, 0≤b1<0.1, a1+b1=1, c1 satisfies chemical valence balance, and M1 is a combination of one or more elements selected from the group consisting of calcium, magnesium, aluminum, titanium, zirconium, tungsten, yttrium, strontium, niobium, molybdenum, vanadium, tantalum, boron, and phosphorus; The chemical formula of the metal hydroxide is (Ni x2 Co y2 Mn z2 Al t2 ) a2 M2 b2 (OH) c2 , 0<x2<1, 0<y2<1, 0≤z2<1, 0≤t2<0.1, x2+y2+z2+t2=1, 0.9<a2≤1, 0≤b2<0.1, a2+b2=1, c2 satisfies chemical valence balance, and M2 is a combination of one or more elements selected from the group consisting of calcium, magnesium, aluminum, titanium, zirconium, tungsten, yttrium, strontium, niobium, molybdenum, vanadium, tantalum, boron, and phosphorus; The lithium salt is a combination of one or more of lithium carbonate, lithium bicarbonate, lithium hydroxide, lithium oxide, lithium acetate, lithium nitrate, and lithium oxalate; The additive is a combination of one or more carbonates, oxides, and hydroxides of element M3, where M3 is a combination of one or more elements of calcium, magnesium, aluminum, titanium, zirconium, tungsten, yttrium, strontium, niobium, molybdenum, vanadium, tantalum, boron, or phosphorus.

3. The lithium-containing composite precursor according to claim 1, characterized in that: The ratio of the metal oxide to the total mass of the metal oxide and the metal hydroxide is 0-1:1, the molar ratio of lithium to metal is 0.70-1.50:1, and the ratio of the additive to the total mass of the metal oxide and the metal hydroxide is 0-0.1:

1.

4. A method for preparing a lithium-containing composite precursor, characterized in that: A method for preparing a lithium-containing composite precursor according to any one of claims 1 to 3, comprising: S1. Preparation of Metal Oxides Dissolving and mixing a first nickel salt, a first cobalt salt, a first manganese salt and / or a first aluminum salt, and an M1 salt to obtain a first metal liquid with a metal concentration of 0.5 to 5.0 mol / L; spray pyrolysis of the first metal liquid to obtain a metal oxide; S2. Preparation of Metal Hydroxides Mixing and dissolving a second nickel salt, a second cobalt salt, a second manganese salt and / or a second aluminum salt to obtain a second metal liquid having a metal concentration of 1.0 to 2.5 mol / L; dissolving the M2 salt to obtain an M2 salt solution; Adding pure water, complexing agent and precipitant into the reaction kettle as reaction bottom liquid; The second metal solution, the complexing agent, the precipitant and the M2 salt solution are continuously added to the reactor simultaneously, and the temperature, the complexing agent concentration and the solution pH in the reactor are maintained to perform a coprecipitation reaction; After the reaction stops, the product is filtered, washed, and dried to obtain a metal hydroxide; S3. Crushing the metal oxide and the metal hydroxide, adding them to pure water with lithium salt and additives for grinding, grinding into nanoparticles with D50 less than 1 μm, and then spray heat treatment to obtain the lithium-containing composite precursor.

5. The method for preparing a lithium-containing composite precursor according to claim 4, wherein: In S1, the first nickel salt is a combination of one or more of nickel nitrate, nickel chloride, and nickel acetate; The first cobalt salt is a combination of one or more of cobalt nitrate, cobalt chloride, and cobalt acetate; The first manganese salt is a combination of one or more of manganese nitrate, manganese chloride, and manganese acetate; The first aluminum salt is a combination of one or more of aluminum nitrate, aluminum chloride, and aluminum acetate; The M1 salt is a combination of one or more of calcium salt, magnesium salt, titanium salt, zirconium salt, tungsten salt, yttrium salt, strontium salt, niobium salt, molybdenum salt, vanadium salt, tantalum salt, borate or phosphate.

6. The method for preparing a lithium-containing composite precursor according to claim 4, wherein: In S2, the second nickel salt is a combination of one or more of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate; The second cobalt salt is a combination of one or more of cobalt sulfate, cobalt chloride, cobalt nitrate, and cobalt acetate; The second manganese salt is a combination of one or more of manganese sulfate, manganese chloride, manganese nitrate, and manganese acetate; The second aluminum salt is a combination of one or more of aluminum sulfate, aluminum chloride, aluminum nitrate, and aluminum acetate; The M2 salt is a combination of one or more of calcium salts, magnesium salts, aluminum salts, titanium salts, zirconium salts, borates, tungsten salts, yttrium salts, strontium salts, niobium salts, molybdenum salts, vanadium salts, tantalum salts, borates or phosphates; The complexing agent is a combination of one or more of ammonia water, ammonium sulfate, ammonium chloride, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, and ammonium acetate; The precipitant is a combination of one or more of sodium hydroxide and potassium hydroxide.

7. The method for preparing a lithium-containing composite precursor according to claim 4, wherein: In S1, the atomization method of the spray pyrolysis is one of pressure spray, centrifugal spray, and ultrasonic spray, the droplet size is less than 100 μm, and the pyrolysis temperature is 600-1200° C.; In S2, the reaction temperature is 40-75°C, the complexing agent concentration is 0.2-0.5 mol / L, and the pH range is 10.60-12.60; In S3, the atomization method of the spray pyrolysis is one of pressure spray, centrifugal spray, and ultrasonic spray, the droplet size is less than 100 μm, and the heat treatment temperature is 150~900°C.

8. A lithium-ion battery cathode material, characterized in that: The lithium-containing composite precursor according to any one of claims 1 to 3 is mixed with a lithium source, calcined under high temperature and oxygen atmosphere, and crushed to obtain a single crystal lithium ion positive electrode material with a chemical formula of Li(Ni x Co y Mn z Al t ) a M b O c , wherein 0<x<1, 0<y<1, 0≤z<1, 0≤t<0.1, x+y+z+t=1, 0.9<a≤1, 0≤b<0.1, a+b=1, c satisfies chemical valence balance, M is a combination of one or more elements of calcium, magnesium, aluminum, titanium, zirconium, tungsten, yttrium, strontium, niobium, molybdenum, vanadium, tantalum, boron or phosphorus, and the particle size D50 of the positive electrode material is 3~5μm.

9. The lithium-ion battery positive electrode material according to claim 1, wherein: The lithium source is a combination of one or more of lithium carbonate, lithium bicarbonate, and lithium hydroxide; The calcination temperature is 650° C. to 1100° C., the oxygen concentration of the oxygen atmosphere is 60% to 100%, and the calcination time is 8 to 16 hours.

10. A lithium-ion battery, characterized in that: It comprises a positive electrode plate, and the positive electrode plate is made of a lithium-ion battery positive electrode material according to claim 8 or 9.

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