A submicron small particle size lithium-rich manganese-based precursor and its preparation method and application

Abstract

This invention provides a submicron-sized lithium-rich manganese-based precursor, its preparation method, and its application. The preparation method includes the following steps: mixing a nickel source, a cobalt source, a manganese source, a doped metal source, an additive, and a solvent to obtain a mixed metal salt solution; the additive includes an organic compound containing heteroatoms; and subjecting the mixed metal salt solution to flame spray pyrolysis to obtain the submicron-sized lithium-rich manganese-based precursor. The preparation method of this invention, based on flame spray pyrolysis, adds an additive containing heteroatoms to the mixed metal salt solution, effectively adjusting the particle surface energy and controlling the growth of crystal nuclei, thereby obtaining submicron-sized spherical lithium-rich manganese precursor particles.

Description

Technical Field

[0001] The invention belongs to the field of battery technology and relates to a submicron small particle size lithium-rich manganese-based precursor and a preparation method and application thereof Background Art

[0002] Due to the unique crystal structure and elemental composition, lithium-rich manganese-based materials exhibit special transition metal redox and anion redox mechanisms, thus having extremely high theoretical specific capacity and high voltage platform. Their energy density is much higher than that of widely commercialized lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4) and ternary materials (LiNi x Co y Mn z O2 or LiNi x Co y Al z O2). In addition, lithium-rich manganese-based materials greatly reduce the amount of expensive Co and Ni, and the material cost is significantly reduced. Therefore, lithium-rich manganese-based materials are considered to be one of the most promising next-generation lithium-ion battery positive electrode materials with broad market prospects.

[0003] The specific capacity of lithium-rich manganese-based positive electrode materials is closely related to the particle size. As the particle size decreases to the submicron level (0.1-1μm), the specific capacity, rate performance and power performance of lithium-rich manganese materials are significantly improved. At present, the mainstream industrial preparation method for layered oxide positive electrode materials, including lithium-rich manganese-based, is the liquid phase co-precipitation method. However, this method produces a lot of wastewater, the byproduct sodium salt is difficult to handle, and it takes a long time; more importantly, this method is suitable for the preparation of spherical materials with a particle size greater than 2μm, and is not suitable for the industrial synthesis of submicron small-particle lithium-rich manganese-based positive electrode materials.

[0004] The spray pyrolysis method includes the preparation of the precursor solution, which is atomized by the atomizer and then carried into the high-temperature reactor by the carrier gas. In the reactor, a series of physical and chemical processes such as solvent evaporation, solute precipitation to form solid particles, particle drying, particle thermal decomposition and sintering are instantly completed. Therefore, this method is easy to prepare powder materials with small particle size and good dispersibility. In addition, this method has many advantages such as no by-products, high green production efficiency, short process, simple process, and uniform and controllable components.

[0005] For example, CN 102956884A discloses a lithium-rich manganese-based material and a preparation method thereof. The preparation method is a sol-spray pyrolysis method, in which a lithium-rich manganese-based positive electrode material is prepared by steps such as precursor sol preparation, spray drying and high-temperature sintering, and the particle size is 1.5-5.0 μm. The method first prepares a sol, which is cumbersome, and also requires acetate raw materials, nitrate raw materials, dispersants and surfactants, which are costly. Another example is CN 110085848A discloses a lithium-rich manganese-based positive electrode material and a preparation method thereof. The preparation method prepares a metal chloride mixed solution of MnCl2 and a metal chloride salt according to a target molar ratio, and then spray pyrolyzes the solution after ultrasonic atomization to obtain a lithium-rich manganese-based oxide precursor, and then sinters the lithium-rich oxide precursor after mixing it with a lithium salt to obtain a lithium-rich manganese-based positive electrode material. However, the particle size distribution of the precursor obtained by this method is between 1-2 μm, and the preparation of a submicron-level (0.1-1 μm) lithium-rich manganese-based precursor is not achieved.

[0006] Based on the above research, it is necessary to provide a method for preparing a submicron small particle size lithium-rich manganese-based precursor, which has low cost and can prepare a submicron small particle size material. Summary of the invention

[0007] The purpose of the present invention is to provide a submicron small-particle lithium-rich manganese-based precursor and a preparation method and application thereof. The preparation method is based on flame spray pyrolysis, and a heteroatom-containing additive is added to a mixed metal salt solution, which effectively adjusts the surface energy of the particles and controls the growth of the crystal nucleus, thereby obtaining submicron-level small-particle lithium-rich manganese precursor spherical particles.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor, the preparation method comprising the following steps:

[0010] (1) mixing a nickel source, a cobalt source, a manganese source, a doping metal source, an additive and a solvent to obtain a mixed metal salt solution;

[0011] The additives include organic substances containing heteroatoms;

[0012] (2) subjecting the mixed metal salt solution of step (1) to flame spray pyrolysis to obtain the submicron small particle size lithium-rich manganese-based precursor.

[0013] The mixed metal salt solution of the present invention is subjected to flame spray pyrolysis, and after nucleation, growth and aggregation, the target particle product is generated and collected. The present invention adjusts the surface energy by adding additives to the mixed metal salt solution, and affects the size of the droplets and the subsequent crystal nucleation and growth process. In addition, the additive of the present invention is an organic matter containing heteroatoms, which can reduce the surface tension of the solution and effectively adjust the surface energy of the crystal nucleus in the initial stage of spray pyrolysis. In addition, the organic matter containing heteroatoms can be partially adsorbed on a specific crystal plane to slow down the particle growth rate, thereby ensuring the generation of submicron-level small-size lithium-rich manganese precursor spherical particles.

[0014] The submicron small particle size mentioned in the present invention refers to a particle size D50 of 0.1-1.0 μm, for example, it can be 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the heteroatom-containing organic matter in step (1) includes nitrogen-containing organic matter and / or oxygen-containing organic matter, preferably a combination of oleylamine and polyethylene glycol.

[0016] When the heteroatom-containing organic matter is a combination of a nitrogen-containing organic matter and an oxygen-containing organic matter, such as a combination of oleylamine and polyethylene glycol, the mass ratio of the nitrogen-containing organic matter to the oxygen-containing organic matter is 1:(0.5-2), for example, it can be 1:0.5, 1:1, 1:1.5 or 1:2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the nitrogen-containing organic matter includes any one of triethanolamine, oleylamine or ethylenediamine, or a combination of at least two of them.

[0018] Preferably, the oxygen-containing organic matter comprises polyethylene glycol and / or isopropanol.

[0019] The present invention preferably uses nitrogen-containing organic matter or oxygen-containing organic matter as the organic matter containing heteroatoms, which can significantly reduce the surface tension of the solution and effectively adjust the surface energy of the crystal nuclei in the initial stage of spray pyrolysis. In addition, the organic matter containing heteroatoms can be partially adsorbed on specific crystal planes, slowing down the growth rate of particles and ensuring that submicron particles are obtained.

[0020] Preferably, in the mixed metal salt solution of step (1), the content of the additive is 3-6wt%, for example, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt% or 6wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Too little or too much content of the additive described in the present invention will affect the particle growth, thereby affecting the material performance. If the content of the additive is too little, it will not be able to play a role in adjusting the surface energy and inhibiting the growth of particles. If the amount of the additive added is too much, it will be adsorbed in the crystal particles, affecting the electrochemical properties of the positive electrode material.

[0022] Preferably, in the mixed metal salt solution of step (1), the total metal ion concentration is 1.5-3 mol / L, for example, 1.8 mol / L, 2 mol / L, 2.5 mol / L, 2.8 mol / L or 3 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the metal element in the doping metal source in step (1) includes any one of K, Na, Li, Ti, Fe, Mg, W, Sn, Sc, V, Cr, Sb, Al, Cu, Mo, Y, Zr, Zn or Nb, or a combination of at least two of them.

[0024] Preferably, the flame temperature of the flame spray pyrolysis in step (2) is 600-900°C, for example, 650°C, 700°C, 800°C or 900°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] The temperature of the flame spray pyrolysis of the present invention is crucial. Since the premise for the doping modification to work is to achieve uniform doping of the doping elements at the atomic level, form stable ionic bonds, and avoid element enrichment and the generation of impurities, the key to achieving uniform doping at the atomic level by spray pyrolysis is to reasonably adjust the flame temperature. On the other hand, in the high-temperature solid-phase sintering stage, compared with the hydroxide precursor, the loading amount and production efficiency of the oxide precursor of the present invention can be increased by 15%-20%. Temperature control is a key factor in ensuring the preparation of the oxide lithium-rich manganese precursor.

[0026] Preferably, the carrier gas for the flame spray pyrolysis in step (2) comprises any one of oxygen, air or nitrogen, or a combination of at least two of them.

[0027] Preferably, the carrier gas flow rate of the flame spray pyrolysis in step (2) is 2-5 L / min, for example, 3 L / min, 4 L / min or 5 L / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, during the flame spray pyrolysis in step (2), the feed rate of the mixed metal salt solution is 30-60 L / h, for example, 40 L / h, 50 L / h or 60 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, during the flame spray pyrolysis in step (2), the nozzle tip diameter used is 0.5-2.5 mm, for example, it can be 1 mm, 1.5 mm, 2.0 mm or 2.5 mm, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] The flame spray pyrolysis step of the present invention comprises: adding a mixed metal salt solution into a feeder of a spray pyrolysis device, atomizing the solution into colloidal particles using a carrier gas nozzle, and spraying the colloidal particles into a flame for pyrolysis to form submicron-sized lithium-rich manganese-based precursor spherical particles.

[0031] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises the following steps:

[0032] (1) mixing a nickel source, a cobalt source, a manganese source, a doping metal source, an additive and a solvent to obtain a mixed metal salt solution, wherein the content of the additive in the mixed metal salt solution is 3-6 wt % and the total metal ion concentration is 1.5-3 mol / L;

[0033] The additive includes organic matter containing heteroatoms, and the organic matter containing heteroatoms includes nitrogen-containing organic matter and oxygen-containing organic matter;

[0034] (2) The mixed metal salt solution of step (1) is fed at a rate of 30-60 L / h, then atomized through a nozzle with a diameter of 0.5-2.5 mm using a carrier gas with a flow rate of 2-5 L / min, and then flame spray pyrolysis is performed at a temperature of 600-900° C. to obtain the submicron small particle size lithium-rich manganese-based precursor.

[0035] In a second aspect, the present invention provides a submicron small particle size lithium-rich manganese-based precursor, and the submicron small particle size lithium-rich manganese-based precursor is prepared by the preparation method described in the first aspect.

[0036] Preferably, the particle size D50 of the submicron small-particle lithium-manganese-rich precursor is 0.1-1.0 μm, for example, it can be 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the chemical formula of the submicron small particle size lithium-rich manganese-based precursor is Ni a Co b Mn c M dO2, wherein 0.1≤a≤0.4, for example, it can be 0.1, 0.2, 0.3 or 0.4, 0≤b≤0.1, for example, it can be 0.01, 0.05 or 0.1, 0.5≤c≤0.8, for example, it can be 0.6, 0.7 or 0.8, 0<d≤0.01, for example, it can be 0.001, 0.005 or 0.01, a+b+c+d=1, and M is any one of K, Na, Li, Ti, Fe, Mg, W, Sn, Sc, V, Cr, Sb, Al, Cu, Mo, Y, Zr, Zn or Nb, or a combination of at least two of them.

[0038] In a second aspect, the present invention provides a lithium-rich manganese-based positive electrode material, which is obtained by mixing and sintering a lithium source and the submicron small-particle lithium-rich manganese-based precursor described in the first aspect.

[0039] Preferably, the sintering temperature is 600-1100°C, for example, 700°C, 800°C, 900°C, 1000°C or 1100°C, and the sintering time is 5-20h, for example, 10h, 15h or 20h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the lithium source comprises LiOH and / or Li2CO3.

[0041] In a third aspect, the present invention provides a lithium-ion battery, wherein the lithium-ion battery comprises the lithium-rich manganese-based positive electrode material as described in the second aspect.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) Different from the wet co-precipitation process, the present invention can achieve the industrial synthesis of submicron (0.1-1.0 μm) small-particle lithium-rich manganese-based positive electrode materials by adding additives and combining them with gas-phase spray pyrolysis, thereby ensuring the specific capacity and power performance of the lithium-rich manganese-based positive electrode materials;

[0044] (2) The spray pyrolysis method only requires relatively cheap precursor solutions and relatively simple equipment, does not involve cumbersome chemical steps, does not produce additional waste liquid, and reduces the pollution to the environment during the preparation process. In addition, the synthesis process is direct, time-saving and low-cost, and can be scaled up industrially.

[0045] (3) Spray pyrolysis can be used to directly prepare oxide precursors on a large scale, with the loading volume and production efficiency increased by 15%-20% compared to hydroxide precursors, which can significantly reduce processing costs. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0047] Example 1

[0048] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor, the preparation method comprising the following steps:

[0049] (1) preparing a solution of NiCl2, CoCl2, MnCl2 and a dopant CrCl3 according to a molar ratio of Ni:Co:Mn:Cr of 0.35:0.018:0.63:0.002, then adding an additive and stirring evenly to obtain a mixed metal salt solution, wherein the content of the additive is 3 wt % and the total metal ion concentration is 2 mol / L;

[0050] The additive includes an organic substance containing heteroatoms, and the organic substance containing heteroatoms is oleylamine and polyethylene glycol in a mass ratio of 1:1;

[0051] (2) adding the mixed metal salt solution of step (1) into the feeder of the spray pyrolysis device at a rate of 50 L / h, using a carrier gas O2 with a flow rate of 4 L / min, atomizing the solution into colloidal particles through a nozzle with a diameter of 1.5 mm, and spraying the colloidal particles into a flame, pyrolyzing at a temperature of 800° C. to obtain the submicron small particle size lithium-rich manganese-based precursor, wherein the chemical formula of the submicron small particle size lithium-rich manganese-based precursor is Ni 0.35 Co 0.018 Mn 0.63 Cr 0.002 O2.

[0052] Example 2

[0053] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor, the preparation method comprising the following steps:

[0054] (1) preparing a solution of NiCl2, CoCl2, MnCl2 and a dopant ZnCl2 according to a molar ratio of Ni:Co:Mn:Zn of 0.2:0.05:0.745:0.005, then adding an additive and stirring evenly to obtain a mixed metal salt solution, wherein the content of the additive in the mixed metal salt solution is 6 wt % and the total metal ion concentration is 3 mol / L;

[0055] The additive includes an organic substance containing heteroatoms, and the organic substance containing heteroatoms is oleylamine and polyethylene glycol in a mass ratio of 1:0.5;

[0056] (2) adding the mixed metal salt solution of step (1) into the feeder of the spray pyrolysis device at a rate of 30 L / h, using a carrier gas O2 with a flow rate of 5 L / min, atomizing the solution into colloidal particles through a nozzle with a diameter of 2.5 mm, and spraying the colloidal particles into a flame, pyrolyzing at a temperature of 900° C. to obtain the submicron small particle size lithium-rich manganese-based precursor, wherein the chemical formula of the submicron small particle size lithium-rich manganese-based precursor is Ni 0.2 Co 0.05 Mn 0.745 Zn 0.005 O2.

[0057] Example 3

[0058] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor, the preparation method comprising the following steps:

[0059] (1) preparing a solution of NiCl2, CoCl2, MnCl2 and a dopant CrCl3 according to a molar ratio of Ni:Co:Mn:Cr of 0.35:0.018:0.63:0.002, then adding an additive and stirring evenly to obtain a mixed metal salt solution, wherein the content of the additive is 4.5 wt % and the total metal ion concentration is 2 mol / L;

[0060] The additive includes an organic substance containing heteroatoms, and the organic substance containing heteroatoms is oleylamine and polyethylene glycol in a mass ratio of 1:2;

[0061] (2) adding the mixed metal salt solution of step (1) into the feeder of the spray pyrolysis device at a rate of 60 L / h, using a carrier gas O2 with a flow rate of 2 L / min, atomizing the solution into colloidal particles through a nozzle with a diameter of 0.5 mm, and spraying the colloidal particles into a flame, pyrolyzing at a temperature of 600° C. to obtain the submicron small particle size lithium-rich manganese-based precursor, wherein the chemical formula of the submicron small particle size lithium-rich manganese-based precursor is Ni 0.35 Co 0.018 Mn 0.63 Cr 0.002 O2.

[0062] Example 4

[0063] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor. The preparation method is the same as that of Embodiment 1 except that the additive in step (1) is oleylamine.

[0064] Example 5

[0065] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor. The preparation method is the same as that of Example 1 except that the additive in step (1) is polyethylene glycol.

[0066] Example 6

[0067] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor. The preparation method is the same as that of Example 1 except that the content of the additive in the mixed metal salt solution in step (1) is 1 wt%.

[0068] Example 7

[0069] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor. The preparation method is the same as that of Example 1 except that the content of the additive in the mixed metal salt solution in step (1) is 8 wt%.

[0070] Example 8

[0071] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor. The preparation method is the same as that of Embodiment 1 except that the pyrolysis is performed at 500° C. in step (2).

[0072] Example 9

[0073] This embodiment provides a method for preparing a submicron small particle size lithium-rich manganese-based precursor. The preparation method is the same as that of Embodiment 1 except that the pyrolysis is performed at 1000° C. in step (2).

[0074] Comparative Example 1

[0075] This comparative example provides a method for preparing a lithium-rich manganese-based precursor. The preparation method is the same as Example 1 except that the additive in step (1) is citric acid.

[0076] Comparative Example 2

[0077] This comparative example provides a method for preparing a lithium-rich manganese-based precursor. The preparation method is the same as Example 1 except that the mixed metal salt solution in step (1) does not contain an additive.

[0078] The lithium-rich manganese-based precursor obtained in the above examples and comparative examples is mixed evenly with Li2CO3 and sintered at 800°C for 10 hours to prepare a submicron-sized lithium-rich manganese-based positive electrode material. The obtained positive electrode material is prepared into a lithium-ion battery by the following preparation method:

[0079] The positive electrode material, the binder polyvinylidene fluoride and the conductive agent Super P are added to N-methylpyrrolidone at a mass ratio of 97:1.5:1.5 and stirred to form a first positive electrode slurry; the first positive electrode slurry is then evenly coated on the positive electrode current collector aluminum foil, and the positive electrode sheet is obtained after drying and rolling;

[0080] Graphite, conductive agent acetylene black, thickener CMC and binder SBR are mixed in a mass ratio of 96:1:1.5:1.5, and deionized water is added as a solvent and stirred to obtain a negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil, and the negative electrode sheet is obtained after drying, cold pressing and slitting;

[0081] Ethylene carbonate EC, ethyl methyl carbonate EMC, and diethyl carbonate DEC are mixed in a volume ratio of 1:1:1, and then fully dried lithium salt LiPF6 is dissolved in the mixed solvent to prepare an electrolyte with a concentration of 1 mol / L;

[0082] The positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence, then wrapped with an aluminum-plastic film, and injected with an electrolyte after drying. After packaging, standing and forming, a lithium-ion battery is obtained; the separator is a PE porous film with a thickness of 11 μm, an air permeability of 280 s / 100 mL, and a porosity of 40%.

[0083] The specific capacity of the obtained lithium-ion battery was tested, and the results are shown in Table 1.

[0084] The specific capacity test method is: using the Blue Electric Battery Test System, at 25°C, the lithium-ion battery is charged and discharged three times in the voltage range of 2.5V to 4.6V at a charge and discharge rate of 0.04A / g (calculated based on the mass of the positive electrode material), and the battery specific capacity is measured;

[0085] The particle size D50 of the lithium-rich manganese-based precursor obtained in the above examples and comparative examples and the above electrochemical performance test results are shown in Table 1:

[0086] Table 1

[0087]

[0088]

[0089] From Table 1 we can see that:

[0090] It can be seen from Example 1 and Comparative Examples 1-2 that the addition of the additive of the present invention can significantly reduce the surface tension of the solution and effectively adjust the surface energy of the crystal nucleus in the early stage of spray pyrolysis; in addition, the organic matter containing heteroatoms can be partially adsorbed on a specific crystal plane, slowing down the growth rate of the particles and controlling the growth of the particles. In particular, the use of heteroatom-containing additives can ensure that the particle size of the obtained particles is at the submicron level, thereby further ensuring the performance of the lithium-rich manganese-based material; it can be seen from Example 1 and Examples 4-7 that the type of the additive of the present invention and the content of the additive will affect the particle size of the material, thereby affecting the material performance; it can be seen from Example 1 and Examples 8-9 that the temperature of the flame spray pyrolysis of the present invention will also affect the material performance.

[0091] In summary, the present invention provides a submicron small-particle lithium-rich manganese-based precursor and a preparation method and application thereof. The preparation method is based on flame spray pyrolysis, and a heteroatom-containing additive is added to a mixed metal salt solution, which effectively adjusts the surface energy of the particles and controls the growth of the crystal nucleus, thereby obtaining submicron small-particle lithium-rich manganese precursor spherical particles.

[0092] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a submicron small particle size lithium-rich manganese-based precursor, characterized in that: The preparation method comprises the following steps: (1) mixing a nickel source, a cobalt source, a manganese source, a doping metal source, an additive and a solvent to obtain a mixed metal salt solution; The additives include organic substances containing heteroatoms; The organic matter containing heteroatoms includes nitrogen-containing organic matter and oxygen-containing organic matter; In the mixed metal salt solution, the content of the additive is 3-6wt%; (2) The mixed metal salt solution of step (1) is subjected to flame spray pyrolysis to obtain the submicron small particle size lithium-rich manganese-based precursor.

2. The preparation method according to claim 1, characterized in that: The nitrogen-containing organic matter includes any one of triethanolamine, oleylamine or ethylenediamine, or a combination of at least two of them.

3. The preparation method according to claim 1, characterized in that: The oxygen-containing organic matter includes polyethylene glycol and / or isopropanol.

4. The preparation method according to claim 1, characterized in that: In the mixed metal salt solution of step (1), the total metal ion concentration is 1.5-3 mol / L.

5. The preparation method according to claim 1, characterized in that: The metal elements in the doping metal source in step (1) include any one of K, Na, Li, Ti, Fe, Mg, W, Sn, Sc, V, Cr, Sb, Al, Cu, Mo, Y, Zr, Zn or Nb, or a combination of at least two of them.

6. The preparation method according to claim 1, characterized in that: The flame temperature of the flame spray pyrolysis in step (2) is 600-900°C.

7. The preparation method according to claim 1, characterized in that: The carrier gas for the flame spray pyrolysis in step (2) includes any one of oxygen, air or nitrogen, or a combination of at least two of them.

8. The preparation method according to claim 1, characterized in that: The carrier gas flow rate of the flame spray pyrolysis in step (2) is 2-5 L / min.

9. The preparation method according to claim 1, characterized in that: During the flame spray pyrolysis in step (2), the feed rate of the mixed metal salt solution is 30-60 L / h.

10. The preparation method according to claim 1, characterized in that: During the flame spray pyrolysis in step (2), the nozzle used has a nozzle diameter of 0.5-2.5 mm.

11. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: (1) mixing a nickel source, a cobalt source, a manganese source, a doping metal source, an additive and a solvent to obtain a mixed metal salt solution, wherein the content of the additive in the mixed metal salt solution is 3-6 wt % and the total metal ion concentration is 1.5-3 mol / L; The additive includes organic matter containing heteroatoms, and the organic matter containing heteroatoms includes nitrogen-containing organic matter and oxygen-containing organic matter; (2) The mixed metal salt solution of step (1) is fed at a rate of 30-60 L / h, then atomized through a nozzle with a diameter of 0.5-2.5 mm using a carrier gas with a flow rate of 2-5 L / min, and then flame spray pyrolysis is performed at a temperature of 600-900° C. to obtain the submicron small particle size lithium-rich manganese-based precursor.

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