High-fluidity lithium battery single-crystal cathode material and preparation method thereof

Abstract

The application discloses a high-fluidity lithium battery single-crystal positive electrode material and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing a precursor, a lithium salt and a modifier, sintering under an oxygen-containing atmosphere at a temperature T1 of 750-850 DEG C for a time t1, obtaining a pre-lithiation intermediate, rapidly cooling the pre-lithiation intermediate in an environment at a temperature T2 of below 10 DEG C for a time t2, obtaining a process sample A, placing the process sample A into an environment at a temperature T3, dispersing and spraying a spheroidizing agent at the same time, drying to obtain a process sample B, rapidly heating and sintering and crystallizing the process sample B in an oxygen-containing atmosphere at a temperature T4 of 850-1000 DEG C for a time t3, and cooling to obtain a single-crystal positive electrode material matrix C; and the single-crystal positive electrode material matrix C is subjected to post-treatment to obtain the high-fluidity lithium battery single-crystal positive electrode material. The application solves the problem of poor fluidity and the manufacturing and use problems caused by the problem.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery materials, in particular to a high-fluidity lithium battery single-crystal positive electrode material and a preparation method thereof. BACKGROUND

[0002] With the development of society and the progress of technology, high energy density, high safety, and long cycle life have become the core demands of lithium batteries. In addition to modifying and improving the performance of materials through some modification methods, the current main way to meet the above core demands is single crystallization.

[0003] The advantages of single crystallization are: (1) stable structure, less prone to micro-cracks, fewer lattice defects in the crystal, conducive to the transmission of lithium ions; (2) dense particle structure, consistent internal arrangement, no grain boundaries, which can inhibit the side reaction with the electrolyte, thereby improving the cycle performance and safety performance, and the thermal stability is also good; (3) strong resistance to volume shrinkage and expansion, high mechanical strength, tap density and compactness; (4) suitable for high-voltage scenarios, which can improve the energy density by increasing the voltage.

[0004] The disadvantages of single crystallization are: (1) large primary particle size, longer ion transmission path, and therefore poor rate performance; (2) higher processing temperature, more sintering times and longer sintering time, so the manufacturing cost is higher; (3) poor flowability of the material leads to agglomeration and hardening, affecting manufacturing, transportation, storage and customer processing.

[0005] The poor flowability of single-crystal materials is analyzed: the flowability of single-crystal particles is related to the irregular shape of the particles with sharp points, small particle size, rough surface, large specific surface area, easy moisture absorption, and the complex relationship between the adhesion, friction, van der Waals force and electrostatic force between the particles hinders the free flow of the particles.

[0006] Based on the above problems in preparation and use, the existing solutions mainly through: increasing particle size, changing particle morphology, coating dispersants or flow aids, reducing material moisture, small packaging, reducing packaging vacuum, reducing packaging and storage environment humidity, increasing the frequency of vibration screen or manual dispersion before slurry preparation. The present application provides another method for improving the poor flowability of single-crystal materials. SUMMARY

[0007] The purpose of the present application is to provide a high-fluidity lithium battery single-crystal positive electrode material and a preparation method thereof, which solves the problem of poor flowability of single-crystal materials in the prior art.

[0008] The present application is implemented as follows: a preparation method of a high-fluidity lithium battery single-crystal positive electrode material, the preparation method comprising the following steps:

[0009] Step one, mix the precursor, lithium salt and modifier uniformly, sinter under oxygen-containing atmosphere at temperature T1 of 750-850 DEG C for time t1, obtain pre-lithiation intermediate, transfer the pre-lithiation intermediate into an environment with temperature T2 of 10 DEG C or below, quench for time t2, obtain process sample A;

[0010] Step two, put process sample A into an environment with temperature T3, disperse while spraying spheroidizing agent, dry, obtain process sample B coated with spheroidizing agent uniformly on the surface;

[0011] Step three, put process sample B into an environment with temperature T4 of 850-1000 DEG C under oxygen-containing atmosphere, quench sintering and crystallization for time t3, obtain single-crystal positive electrode material matrix C after cooling;

[0012] Step four, after-treatment of single-crystal positive electrode material matrix C, obtain high-fluidity lithium single-crystal positive electrode material.

[0013] The application controls the conditions of pre-lithiation process, realizes primary fusion of lithium and precursor and controls primary particle size, makes part of lithium insert into crystal cell to realize primary particle growth and disintegration, part of lithium fuse with primary particle surface for subsequent secondary growth and recrystallization of particles; then quench to an environment with temperature T2 at high temperature, make the pre-lithiation intermediate agglomerate in an expanded state at high temperature shrink rapidly at low temperature, generate internal stress between particles to realize disintegration of agglomerate, meanwhile, the crystallization state of pre-lithiation is reserved; after spraying spheroidizing agent in an environment with temperature T3, realize uniform coating of disintegrated particles, quench sintering again to make primary particle crystal cell volume increase rapidly, realize space enrichment of inserted lithium, and the residual lithium on the surface of primary particle can insert into crystal lattice rapidly, make primary particle grow, grow into a highly spherical state under the action of spheroidizing agent, and because the lithium salt of pre-lithiation has been decomposed completely and fused with single particle, the lithium salt in high temperature does not move in the gap between particles under the isolation of spheroidizing agent, the contact area between particles is less, and the adhesion is less, the material after high-temperature sintering is more loose, and the hardening is reduced; finally, after-treatment obtains high-fluidity lithium single-crystal positive electrode material.

[0014] In the application, the sintering mode of quenching and quenching can reduce the side reaction in the crystallization process, and the crystal lattice defects are less.

[0015] In the application, the purpose of spheroidizing agent is to modify the irregular particle tip into spherical or spherical-like particles, so that the material particle is smooth and has better fluidity, which is beneficial to further improve the compaction density of the material, and the uniform coating layer formed by spheroidizing agent after sintering reduces the surface water adsorption.

[0016] The single crystal positive electrode material prepared by the present invention has a highly rounded spherical or quasi-spherical morphology, a smooth particle surface, low moisture absorption, low adsorption force between particles, a small repose angle, and high fluidity, which solves the problems of agglomeration and compaction of single crystal materials and improves the manufacturing, transportation, storage, and client processing links.

[0017] The single crystal positive electrode material prepared by the present invention has high vibration and compaction, stable crystal structure and excellent electrochemical performance, is safe and stable under high voltage, has high specific capacity and long cycle life, and can combine the characteristics of high energy density, high safety and long cycle life.

[0018] A further technical solution of the present invention is that in step 1, the sintering time t1 is 1 to 6 hours, and the sintering time t2 is 0.5 to 2 hours. The pre-lithiation intermediate in step 1 is a partially disintegrated non-spherical agglomerate of primary particles, wherein the primary particles are small single crystal particles with a diameter of 1.5 to 2.5 μm. This further ensures that the pre-lithiation process achieves primary fusion of lithium and the precursor and controls the size of the primary particles, which is conducive to the subsequent secondary growth and crystallization of the particles.

[0019] A further technical solution of the present invention is: in the step 1, the precursor is at least one of an oxide, a hydroxide, a carbonate, and an organic acid salt, and the precursor contains nickel, cobalt, and zero, one, or more of Al, Mn, and Ti; the lithium salt is at least one of a lithium-containing oxide, hydroxide, carbonate, phosphate, nitrate, and an organic acid salt; the modifier is at least one of an oxide, a halide, a carbonate, a hydroxide, a phosphide, a boride, and an organic compound containing an effective element, and the effective element is at least one of Al, Mn, Ti, Zr, Nb, Sr, W, B, Zn, Ta, Tl, Ga, V, Sn, Sb, Mo, Cs, Rb, Ru, In, and Ge.

[0020] A further technical solution of the present invention is that the lithium salt is selected from at least one of lithium hydroxide, lithium oxide, lithium fluoride, lithium carbonate, lithium nitrate and lithium acetate.

[0021] A further technical solution of the present invention is: in the step one, the precursor, lithium salt and modifier are mixed evenly, and the mixture is placed in furnace one for calcination, and furnace one is any one of a box furnace, a roller furnace, a push-plate furnace, a tube furnace, and a rotary furnace; in the step three, process sample B is placed in furnace two for calcination and crystallization, and furnace two is any one of a box furnace, a roller furnace, and a push-plate furnace; in the steps one and three, the oxygen-containing atmosphere is dry air or a gas with an oxygen concentration not lower than that of air, and the specific oxygen concentration is adjusted according to the material composition.

[0022] The target temperature of the pre-lithiation sintering process in the step one is 750-850 DEG C, the pre-lithiation sintering time is 1-6h, and the obtained pre-lithiation intermediate is a partially disintegrated non-spherical agglomerate of primary particles, the primary particle diameter of the agglomerate is 1.5-2.5 μm, and the primary particle morphology is a small single-crystal particle with irregular shape; in the step one, the quenching temperature is below 10 DEG C, and the quenching mode includes one or more of gas cooling, external auxiliary liquid cooling and freezing; the quenching treatment is as follows: the pre-lithiation intermediate in a high-temperature state is rapidly placed in a coolant environment below 10 DEG C for cooling, and the cooling time is 0.5-2h; the process sample A after cooling is in a disintegrated and dispersed primary particle state, and the particle diameter and morphology of the primary particles of the pre-lithiation intermediate are retained.

[0023] A further technical solution of the present application is that the temperature T3 in the step two is -10 DEG C-200 DEG C; the drying treatment temperature is 100 DEG C-250 DEG C, and the drying treatment time is 1h-20h.

[0024] A further technical solution of the present application is that the spheroidizing agent in the step two is at least one of an oxide, a halide, a carbonate, a hydroxide, a phosphide, a boride or an organic compound containing an effective element; the effective element is at least one of Mg, Si, Ca, Ba, Fe, Sc, Y, La, Ce, Na and K.

[0025] A further technical solution of the present application is that in the step two, the process sample A is dispersed by being put into a rotary furnace, the volume of the material put into the rotary furnace does not exceed one half of the effective volume in the rotary furnace cavity; the rotary speed of the rotary furnace is adjusted according to actual requirements; the multi-directional spraying system in the rotary furnace has a stacking angle covering the effective volume in the rotary furnace cavity, the spraying process can be continuous or intermittent, the spraying head has a self-cleaning function, the spraying medium can be single medium or mixed medium of liquid, gas and solid, and the amount, type of the spraying medium and the time of the spraying process are determined by the properties of the spheroidizing agent, the designed amount and the material mixing uniformity in the rotary furnace.

[0026] The spheroidizing agent is brought in by the spraying medium of the spraying system; if the spheroidizing agent is an insoluble solid, the particle diameter thereof needs to be lower than 100nm; the spheroidizing agent functions to realize spheroidization of the primary particles in the step three calcination process.

[0027] In the step two, the process sample B is in a dispersed primary particle state, retains the particle diameter and morphology of the primary particles of the process sample A, and the surface of the primary particles is coated with uniform coating, and the form of the coating is determined by the properties of the spheroidizing agent.

[0028] The further technical scheme of the present application is that in the step three, the calcination crystallization time t3 is 2h-24h. In the step three, the target temperature two is 850-1000 DEG C, the calcination crystallization time is 2h-24h; the entering target temperature zone is a sudden heating process without a temperature rising buffer section; the obtained single crystal positive electrode material substrate C single particle has a high roundness spherical or spherical-like single crystal morphology, a smooth surface or a full coverage uniform coating film, and the single particle size is 2.0-4.5um.

[0029] The further technical scheme of the present application is that in the step four, the post-processing step includes: after the single crystal positive electrode material substrate C is crushed and air-powdered, batch mixing, screening, magnetic removal, and then electrostatic removal, the single crystal positive electrode material substrate C is obtained.

[0030] The further technical scheme of the present application is that in the step four, the crushing and air-powdering parameters are adjusted according to the state of the substrate C; the secondary coating and sintering or no coating are determined by the material type and the use approach, and whether to coat is determined according to the use of the material; if the secondary coating and sintering are needed, the coating agent used for coating can be at least one of oxides, carbonates, hydroxides, phosphides, borides, halides or organic compounds containing at least one element of Al, Mg, K, Ti, Nb, W, B, Mo, Si, Ca, Ba, C, Fe, the coating agent can be in any state of liquid and / or solid and / or gas, the coating method is determined by the state of the coating agent, if the insoluble solid is contained, the particle size needs to be less than 100nm, and part of the substances in the coating agent can also play the role of anti-caking agent; if the secondary coating and sintering are needed, the sintering furnace can be any one of a box furnace, a roller furnace, a push plate furnace, a tube furnace, a rotary furnace, the sintering atmosphere is divided into an oxygen-containing atmosphere and an oxygen-free atmosphere, the sintering temperature is 150 DEG C-750 DEG C, the sintering time is 1h-20h, and the crushing method after sintering can be mechanical crushing and / or screening through a screen mesh; the pre-product D has a high roundness spherical or spherical-like single crystal morphology, which can be a single particle or a single particle aggregate of 10 or less, a smooth surface, low moisture absorption, an angle of repose less than 40 DEG, and a particle size D50 of 2.0-6.5um.

[0031] The material of the present application is subjected to the electrostatic removal device before packaging, so as to eliminate the electrostatic adhesion force caused by the collision and friction between particles in the processes of crushing, air-powdering, batch mixing, screening and the like, improve the flowability of the material, and reduce the soft agglomeration of the material in storage and transportation after packaging. The electrostatic removal device can be an ion eliminator or a high-voltage generator; the single crystal positive electrode material finished product E obtained after the electrostatic removal is the high flowability lithium single crystal positive electrode material of the present application, the angle of repose is less than 40 DEG, and the particle size D50 is 2.0-6.5um.

[0032] A further technical solution of the present application is that the post-processing step in step four comprises: the single-crystal positive electrode material substrate C is crushed and air-powdered, then is subjected to secondary coating and sintering, batch mixing, screening, magnetic removal, and then electrostatic removal to obtain the single-crystal positive electrode material substrate C.

[0033] A further technical solution of the present application is that the coating agent for the secondary coating is at least one of oxides, carbonates, hydroxides, phosphides, borides, halides, and organic compounds containing effective elements, the effective elements are at least one of Al, Mg, K, Ti, Nb, W, B, Mo, Si, Ca, Ba, C, and Fe, the secondary sintering temperature is 150 DEG C to 750 DEG C, and the sintering time is 1 h to 20 h.

[0034] In the present application, the quenching is directly entering the target temperature without a cooling process, and the quenching is directly entering the target temperature without a heating process.

[0035] The present application also provides a high-flowability single-crystal positive electrode material for lithium batteries, which is obtained by the preparation method of the present application. 1+n Ni x Co y M z A m O 2+w , wherein -0.5 <= n <= 0.5, 0.2 <= x < 1, 0 <= y <= 0.4, 0 <= z <= 2, 0 <= m <= 0.01, -0.5 <= w <= 2, M is zero, one or more of Al, Mn and Ti, A is zero, one or more of Al, Mn, Mg, Ti, Fe, Zr, Y, Ca, Nb, Sr, Sc, W, B, Ba, Zn, Ce, Ta, Tl, Ga, La, V, Sn, Sb, Si, Mo, Cs, Rb, Ru, In, Ge, K, Na, C, H, F, Cl, P, the rest angle of the high-flowability single-crystal positive electrode material for lithium batteries is less than 40 DEG, and the particle size D50 is 2.0 to 6.5 mu m.

[0036] A further technical solution of the present application is that the number of moles of the effective elements of the modifier meets the range of m in the chemical formula of the present application, the m range of the modifier is 0.0005 to 0.005, the number of moles of the effective elements of the spherification agent meets the range of m in the chemical formula of the present application, the m range of the spherification agent is 0.0005 to 0.005, the number of moles of the effective elements of the coating agent meets the range of m in the chemical formula of the present application, the m range of the coating agent is preferably 0.0005 to 0.004, the number of moles of lithium elements of the lithium source meets the range of 1+n in the chemical formula of the present application, the number of moles of lithium elements is 0.5 to 1.5, and the number of moles of the effective elements of the precursor meets the range of x, y and z in the chemical formula of the present application, the number of moles of the effective elements of the precursor is 0.2 to 3.4.

[0037] The beneficial effects of the present application are: 1. The present application provides a preparation method of high flowability lithium battery single crystal positive electrode material, solves the poor flowability of single crystal material in the prior art and the manufacturing and use problems caused by the problem, and improves the material performance through modification means. The high flowability lithium battery single crystal positive electrode material includes high roundness spherical or spherical morphology, smooth single particle surface, low moisture absorption, low adsorption force between particles, small rest angle and high flowability, solves the agglomeration and hardening problems of single crystal material, and improves the manufacturing, transportation, storage and customer processing links;

[0038] 2. The present application controls the pre-lithiation process to realize the primary fusion of lithium and precursor, controls the primary particle size, realizes particle depolymerization through high-temperature quenching, realizes uniform coating of depolymerized particles by using a rotary furnace and a customized spraying system, realizes primary particle spheroidization growth through reheat calcination, and finally eliminates the electrostatic adhesion force between particles through a customized electrostatic elimination device to obtain a high flowability lithium battery single crystal positive electrode material. The pre-lithiation of the present application is to embed part of the lithium into the crystal cell to realize the growth and disintegration of the primary particles, and part of the lithium is fused with the surface of the primary particles for subsequent secondary growth and recrystallization of the particles. The purpose of the quenching treatment of the present application is to make the pre-lithiation intermediate agglomerates in the high-temperature expansion state rapidly shrink at low temperature to generate internal stress between the particles, so as to realize the depolymerization of the agglomerates, while the crystallization state of pre-lithiation is retained.

[0039] 3. The present application adopts calcination plus spraying system to make the primary particles uniformly coated with spheroidizing agent and realize continuous operation in the production line, reduce the production breakpoint process; the purpose of the spheroidizing agent is to modify the irregular particle tip corner morphology into spherical or spherical particles, so that the material particles are round and smooth and have better flowability, which is beneficial to further improve the compaction density of the material, and the uniform coating layer formed by the re-calcination of the spheroidizing agent reduces the surface moisture adsorption.

[0040] 4. The purpose of the reheat calcination of the present application is to rapidly heat the primary particle crystal cell volume to make the lithium insertion space abundant, and the residual lithium fused with the surface of the primary particles can be quickly embedded into the crystal lattice to make the primary particles grow. At the same time of growth, under the action of the spheroidizing agent, the particles grow into a highly spherical state. And because the lithium salt of pre-lithiation has been completely decomposed and fused with the single particles, under the isolation of the spheroidizing agent, the high-temperature lithium salt will not wander in the gap between the particles. The contact area between the particles is smaller, the adhesion is less, the material sintered at high temperature will be more loose, and the hardening is reduced. In addition, the sintering mode of quenching and reheat can reduce the side reactions in the crystallization process, and the crystal lattice defects are less.

[0041] 5、The material of the present application is subjected to an electrostatic elimination device before packaging, aiming at eliminating the electrostatic adhesion force caused by the collision and friction between particles in the processes of crushing, air-powdering, batch mixing, screening, etc., improving the flowability of the material, and reducing the soft agglomeration of the material in storage and transportation after packaging.

[0042] 6、The single-crystal positive electrode material prepared by the present application has high tap density and compaction, stable crystal structure, excellent electrochemical performance, high voltage safety and stability, high specific capacity, long cycle life, and can have the characteristics of high energy density, high safety, long cycle life, etc. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 XRD patterns of the single-crystal positive electrode material obtained in Example 1 and the comparative material;

[0044] Figure 2 SEM image of the pre-lithiated intermediate obtained in Example 1 at a magnification of 1000 times;

[0045] Figure 3 SEM image of Process Sample A obtained in Example 1 at a magnification of 1000 times;

[0046] Figure 4 SEM image of Base Sample C obtained in Example 1 at a magnification of 1000 times;

[0047] Figure 5 SEM image of finished product Sample E obtained in Example 1 at a magnification of 10000 times;

[0048] Figure 6 SEM image of the single-crystal positive electrode material obtained in the comparative example at a magnification of 10000 times;

[0049] Figure 7 First charge-discharge curve of 2032 button cell made of the single-crystal positive electrode material obtained in Example 1 and the single-crystal positive electrode material of the comparative example at room temperature, current density 0.2C, voltage 3.0V-4.5V;

[0050] Figure 8 Charge-discharge cycle curve of 2032 button cell made of the single-crystal positive electrode material obtained in Example 1 and the single-crystal positive electrode material of the comparative example at room temperature, current density 1C, voltage 3.0V-4.5V. DETAILED DESCRIPTION

[0051] Objects, advantages and novel features of the application will become more apparent to those skilled in the art from the following detailed description accompanied with the related drawings. The following DETAILED DESCRIPTION of the application is given for the purpose of describing and disclosing the best mode of the application and should in no way be used to limit or otherwise restrict the scope of the application, which is defined in the claims.

[0052] As used herein the terms "about" and "substantially" are used to describe and account for small fluctuations, such as due to measurement or other experimental error, in the value of a parameter such as temperature, pressure, time, etc. Such terms should therefore be understood to denote that the value of the parameter is within a range of acceptable values, for example, within 10%, within 5%, within 1%, or within 0.1% of the stated value.

[0053] "comprising," "including," "carrying," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, a step, a method, an article, or an apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0054] The transitional phrase "consisting of" excludes any element, step, or ingredient not specified. If used in the claims, this phrase shall serve only as a definition of such claim and shall not be construed as a limitation on the claim's scope. When the phrase "consisting of" follows the transitional word "a" or "an," this serves to further define the name of the genus of which the modifier is a member.

[0055] For the purposes of this application, the following terms shall have the meanings indicated below:

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise noted, particular conditions of the embodiments described herein are intended to be performed under conventional conditions or manufacturer's recommended conditions. Unless otherwise noted, the reagents or instruments used are conventional products available commercially.

[0057] The present application provides a preparation method of a high flowability lithium battery single crystal cathode material, the preparation method comprising the following steps:

[0058] Step one, mix the precursor, lithium salt and modifier uniformly, sinter in oxygen-containing atmosphere at temperature T1 of 750-850℃ for sintering time t1, obtain pre-lithiated intermediate, transfer the pre-lithiated intermediate into environment with temperature T2 of 10℃ or below for quenching time t2, obtain process sample A;

[0059] In step one, the sintering time t1 is 1-6h, and the time t2 is 0.5-2h; in step one, the pre-lithiated intermediate is partially disintegrated non-spherical agglomerates piled by primary particles, and the primary particles are small single crystal particles with diameter of 1.5-2.5μm.

[0060] In step one, the precursor is at least one of oxide, hydroxide, carbonate and organic acid salt, and the precursor contains nickel and cobalt and zero, one or more of Al, Mn and Ti; the lithium salt is at least one of oxide, hydroxide, carbonate, phosphate, nitrate and organic acid salt containing lithium, and the modifier is at least one of oxide, halide, carbonate, hydroxide, phosphide, boride and organic compound containing effective element, and the effective element is at least one of Al, Mn, Ti, Zr, Nb, Sr, W, B, Zn, Ta, Tl, Ga, V, Sn, Sb, Mo, Cs, Rb, Ru, In and Ge; the lithium salt is selected from at least one of lithium hydroxide, lithium oxide, lithium fluoride, lithium carbonate, lithium nitrate and lithium acetate.

[0061] In step one, mix the precursor, lithium salt and modifier uniformly, calcine in furnace one, and furnace one is any one of box furnace, roller furnace, push plate furnace, tube furnace and rotary furnace; in step three, calcine and crystallize process sample B in furnace two, and furnace two is any one of box furnace, roller furnace and push plate furnace; in step one and step three, the oxygen-containing atmosphere is dry air or gas with oxygen concentration not lower than air, and the specific oxygen concentration is adjusted according to material components.

[0062] Step two, disperse process sample A in environment with temperature T3 while spraying spheroidizing agent, and dry to obtain process sample B coated with spheroidizing agent uniformly on surface;

[0063] In step two, the temperature T3 is -10-200℃; the drying temperature is 100-250℃, and the drying time is 1-20h.

[0064] In the step 2, process sample A is put into the rotary kiln and dispersed by rotation, and the volume of the material put into the rotary kiln does not exceed one half of the effective volume of the rotary kiln cavity; the rotation speed of the rotary kiln is adjusted according to actual needs; the superposition angle of the multi-directional spraying system in the rotary kiln covers the effective volume of the rotary kiln cavity, the spraying process can be continuous or intermittent, the nozzle has a self-cleaning function, the spraying medium can be a single medium or a mixed medium among liquid, gas, and solid, and the amount, type and time of the spraying medium are determined by the properties and design amount of the spheroidizing agent and the uniformity of material mixing in the rotary kiln.

[0065] In the step 2, the spheroidizing agent is at least one of oxides, halides, carbonates, hydroxides, phosphides, borides, or organic compounds containing effective elements; the effective elements are at least one of Mg, Si, Ca, Ba, Fe, Sc, Y, La, Ce, Na, and K.

[0066] The spheroidizing agent is introduced by the spraying medium of the spraying system; if the spheroidizing agent is an insoluble solid, its particle size must be less than 100 nm; the function of the spheroidizing agent is to spheroidize the primary particles during the calcination process in step three.

[0067] In the step 2, process sample B is in a dispersed primary particle state, retaining the particle size and morphology of the primary particles of process sample A, and the surface of the primary particles is uniformly coated with a coating, the morphology of the coating being determined by the properties of the spheroidizing agent.

[0068] Step 3: In an oxygen-containing atmosphere, the process sample B is placed in an environment with a temperature T4 of 850°C to 1000°C for rapid calcination and crystallization. The calcination time is t3, and after cooling, a single crystal positive electrode material matrix C is obtained.

[0069] In step 3, the calcination crystallization time t3 is 2 hours to 24 hours. In step 3, the target temperature 2 is 850°C to 1000°C, and the calcination crystallization time is 2 hours to 24 hours. Entering the target temperature zone is a sudden heating process without a temperature rise buffer stage. The obtained single crystal positive electrode material matrix C single particles have a highly rounded spherical or quasi-spherical single crystal morphology, a smooth surface or a fully covered uniform coating film, and a single particle size of 2.0 to 4.5 μm.

[0070] Step 4: The single crystal positive electrode material substrate C is post-processed to obtain a high-fluidity lithium battery single crystal positive electrode material.

[0071] The post-processing steps in step four include: the post-processing steps in step four include: the single crystal positive electrode material matrix C is crushed and gas-powdered, and then subjected to secondary coating and sintering or not, and then batch mixed, screened, demagnetized and then destaticized to obtain the single crystal positive electrode material matrix C.

[0072] The coating agent for the secondary coating is at least one of oxides, carbonates, hydroxides, phosphides, borides, halides, organic compounds containing at least one of Al, Mg, K, Ti, Nb, W, B, Mo, Si, Ca, Ba, C, Fe, and the secondary sintering temperature is 150-750 DEG C and the sintering time is 1-20 hours.

[0073] In the fourth step, the crushing and air-powdering parameters are adjusted according to the state of the substrate C; the secondary coating and sintering or no coating and sintering are determined by the material type and the use approach, and whether to coat is determined according to the use of the material; if the secondary coating and sintering are needed, the coating agent can be at least one of oxides, carbonates, hydroxides, phosphides, borides, halides or organic compounds containing at least one of Al, Mg, K, Ti, Nb, W, B, Mo, Si, Ca, Ba, C, Fe, and the coating agent can be in any state of liquid and / or solid and / or gas, and the coating mode is determined by the state of the coating agent; if the coating agent contains insoluble solids, the particle size thereof needs to be less than 100 nm, and part of the substances in the coating agent can also play the role of anti-caking agent; if the secondary coating and sintering are needed, the sintering furnace can be any one of a box-type furnace, a roller-type furnace, a push plate-type furnace, a tube-type furnace and a rotary furnace, the sintering atmosphere is divided into an oxygen-containing atmosphere and an oxygen-free atmosphere, the sintering temperature is 150-750 DEG C, the sintering time is 1-20 hours, and the crushing mode after sintering can be mechanical crushing and / or sieving through a screen; the pre-product D has a spherical or quasi-spherical single crystal morphology with high roundness, which can be a single particle or an aggregate of less than 10 single particles, has a smooth surface, low moisture absorption and an angle of repose less than 40 DEG, and the particle size D50 is 2.0-6.5 microns.

[0074] A high-flowability lithium battery single crystal positive electrode material is prepared by the above method, and the chemical formula of the positive electrode material is: Li 1+n Ni x Co y M z A m O 2+w , wherein -0.5≤n≤0.5, 0.2≤x<1, 0≤y≤0.4, 0≤z≤2, 0≤m≤0.01, -0.5≤w≤2; M is zero, one or more of Al, Mn and Ti; A is zero, one or more of Al, Mn, Mg, Ti, Fe, Zr, Y, Ca, Nb, Sr, Sc, W, B, Ba, Zn, Ce, Ta, Tl, Ga, La, V, Sn, Sb, Si, Mo, Cs, Rb, Ru, In, Ge, K, Na, C, H, F, Cl, P; the high-flowability lithium battery single crystal positive electrode material has an angle of repose less than 40 DEG and a particle size D50 of 2.0-6.5 microns.

[0075] The molar number of the effective element of the modifier meets the range of m in the formula of the present application, and the m of the modifier ranges from 0.0005 to 0.005; the molar number of the effective element of the spherification agent meets the range of m in the formula of the present application, and the m of the spherification agent ranges from 0.0005 to 0.005; the molar number of the effective element of the coating agent meets the range of m in the formula of the present application, and the m of the coating agent preferably ranges from 0.0005 to 0.004; the molar number of the lithium element of the lithium salt in the positive electrode material ranges from 0.5 to 1.5, and the molar number of the effective element of the precursor ranges from 0.2 to 3.4.

[0076] The specific implementation is as follows:

[0077] Example 1

[0078] The preparation steps of the single-crystal positive electrode material of the present example are as follows:

[0079] Step one: Li2CO3 and Ni 0.5 Co 0.2 Mn 0.3 (OH)2 are weighed according to the molar ratio of 1.07:1, and Ta2O5 (wherein the mass ratio of Ta is 2000ppm) is added and placed in a high-efficiency mixer for high-speed mixing at a speed of 300r / min for 30min to obtain high-mixing material; the high-mixing material is loaded into a sagger and placed in a roller hearth furnace, and after reaching the target temperature zone by gradient heating, sintering is performed at 800℃ for 6h, and air is introduced into the furnace during the sintering process, and after the sintering time ends, a pre-lithiation intermediate is obtained, and then the high-temperature pre-lithiation intermediate is rapidly transferred into a liquid nitrogen-assisted cooling incubator for quenching, the temperature in the incubator is-10℃, and the cooling is completed after incubation for 1h to obtain the cooled process sample A;

[0080] Step two: the process sample A is discharged from the discharge port of the cooling device and quantitatively fed into a rotary furnace at room temperature through a weighing system, the rotary furnace is rotated at a speed of 10r / min for 15min until the material is uniformly dispersed, then the rotary furnace is continuously rotated and a certain amount of cerium acetate (Ce mass ratio 2000ppm) with ethanol as the medium is sprayed into the furnace through a multi-directional spraying system in the rotary furnace, intermittent spraying, duration 1h, after spraying, the rotary furnace is continuously rotated for 30min until the material is uniformly mixed, the exhaust port of the rotary furnace is opened and the temperature of the rotary furnace is raised to 120℃, and drying is performed for 2h to obtain process sample B uniformly coated with cerium acetate on the surface;

[0081] Step three: the process sample B is transferred into the weighing system through the discharge port of the rotary furnace, and the sagger is discharged and loaded into the roller hearth furnace, and calcination and crystallization are directly performed at the target temperature of 950℃ for 6h under air atmosphere, and finally the furnace is cooled down through the furnace cooling zone and the sagger is discharged, to obtain single-crystal positive electrode material base C;

[0082] Step four: after the single crystal cathode material base C is broken, gas-powdered, and coated with Al2O3 (Al mass ratio 6000ppm) for the second time, the high-efficiency mixer is used for coating and mixing at a speed of 300r / min for 30min, the dry coating material is loaded into the roller furnace, sintered at 600℃ for 6h in an air atmosphere after reaching the target temperature zone through gradient heating, and finally cooled and discharged from the furnace through the furnace cooling zone, to obtain the pre-product D;

[0083] After the pre-product D enters the packaging system, batch mixing, screening, and magnetic removal, it enters the static electricity removal device, and the material after static electricity removal is the single crystal cathode material finished product E, which is then weighed and discharged into a packaging bag for sealing and packaging.

[0084] Example 2

[0085] The preparation steps of the single crystal cathode material of the present example are as follows:

[0086] Step one: Li2CO3 and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and ZrO2 (Zr mass ratio 4000ppm) are weighed according to the molar ratio of 1.06:1 and placed in a high-efficiency mixer for high-speed mixing at a speed of 300r / min for 30min to obtain high-mixing material; the high-mixing material is loaded into a sagger and placed in a roller furnace, sintered at 790℃ for 6h after reaching the target temperature zone through gradient heating, and air is introduced into the furnace during sintering, and the pre-lithiated intermediate is obtained after the sintering time ends, then the high-temperature pre-lithiated intermediate is quickly transferred into a liquid nitrogen-assisted cooling incubator for quenching, the temperature in the incubator is -10℃, and the cooling is completed after 1h of incubation, to obtain the cooled process sample A;

[0087] Step two: the process sample A is discharged from the cooling device through the weighing system and placed into a rotary furnace at room temperature, the rotary furnace is rotated at a speed of 10r / min for 15min until the material is evenly dispersed, then the rotary furnace continues to rotate and sprays a certain amount of LaCl3 (La mass ratio 1000ppm) with ethanol as the medium into the furnace through the multi-directional spraying system customized for the rotary furnace, intermittent spraying, duration 1h, after spraying, continue to rotate for 30min to mix evenly, open the exhaust port of the rotary furnace and raise the temperature of the rotary furnace to 120℃, dry for 2h, to obtain the process sample B coated with LaCl3 on the surface;

[0088] Step three: the process sample B is transferred into the weighing system through the rotary furnace discharge port, and is loaded into the roller furnace, sintered and crystallized at 900℃ for 8h in an air atmosphere after reaching the target temperature zone, and finally cooled and discharged from the furnace through the furnace cooling zone, to obtain the single crystal cathode material base C;

[0089] Step four: after the single crystal cathode material substrate C is broken, gas-powdered, and coated with Al2O3 (Al mass ratio 3000ppm) for the second time, the high-efficiency mixer is used for coating and mixing at a speed of 300r / min for 30min, the dry coating material is loaded into the roller furnace, sintered at 600℃ for 6h in an air atmosphere after the gradient temperature zone reaches the target temperature zone, and finally cooled and discharged from the furnace through the furnace cooling zone, to obtain the pre-product D;

[0090] After the pre-product D enters the packaging system, batch mixing, screening, and magnetic removal, it enters the customized electrostatic removal device, and the material after electrostatic removal is the single crystal cathode material product E, which is then weighed and discharged into a packaging bag for sealing and packaging.

[0091] Example 3

[0092] The preparation steps of the single crystal cathode material of the present example are as follows:

[0093] Step one: LiOH·H2O and Ni 0.7 Co 0.1 Mn 0.2 (OH)2 and ZrO2 (wherein the mass ratio of Zr is 3000ppm) are weighed according to the molar ratio of 1.05:1 and placed in a high-efficiency mixer, mixed at a speed of 300r / min for 30min, to obtain high-mixing material; the high-mixing material is loaded into a sagger and placed in a roller furnace, sintered at 790℃ for 4h after the gradient temperature zone reaches the target temperature zone, and oxygen is introduced into the furnace during the sintering process (oxygen concentration 90% and above), and the pre-lithiated intermediate is obtained after the sintering time ends, then the high-temperature pre-lithiated intermediate is quickly transferred into a cold storage box for rapid cooling, the temperature in the cold storage box is-5℃, and the cooling is completed after 1h of heat preservation, to obtain the cooled process sample A;

[0094] Step two: the process sample A is discharged from the cooling device through the weighing system, and a certain amount of BaCl2 (Ba mass ratio 1500ppm) is sprayed into the rotary furnace at room temperature through the multi-directional spraying system of the rotary furnace, and the rotary furnace is continuously rotated and sprayed intermittently for 1h, and then the rotary furnace is continuously rotated for 40min after the spraying is completed, and the rotary furnace is opened for exhaust and the temperature is increased to 150℃, and dried for 5h, to obtain the process sample B coated with BaCl2 on the surface;

[0095] Step three: the process sample B is transferred into the weighing system through the rotary furnace discharge port, and then loaded into the roller furnace, calcined and crystallized at 870℃ for 10h in an oxygen atmosphere (oxygen concentration 90% and above), and finally cooled and discharged from the furnace through the furnace cooling zone, to obtain the single crystal cathode material substrate C;

[0096] Step four: after the single crystal positive material matrix C is broken and air-powdered, secondary coating B2O3 (B mass ratio 1000 ppm) is coated and mixed by using a high-efficiency mixer at a speed of 300 r / min for 30 min, and the dry coating is loaded into a roller furnace, sintered at 500 ℃ for 6 h in an oxygen atmosphere (oxygen concentration 90% and above), and then cooled and discharged from the furnace through the furnace cooling zone, to obtain a pre-product D;

[0097] After the pre-product D enters the packaging system, batch mixing, screening and magnetic removal are performed, and then the material after static electricity removal is the single crystal positive material product E. After weighing, the product E is loaded into a packaging bag for sealing and packaging.

[0098] Example 4

[0099] The preparation steps of the single crystal positive material of the present example are as follows:

[0100] Step one: LiOH·H2O and Ni 0.8 Co 0.1 Mn 0.1 (OH)2 are weighed according to a molar ratio of 1.04:1, and ZrO2 (wherein the mass ratio of Zr is 2000 ppm) is added and placed in a high-efficiency mixer, mixed at a speed of 300 r / min for 30 min, to obtain a high-mixing material; the high-mixing material is loaded into an anvil and placed in a roller furnace, sintered at 780 ℃ for 4 h after reaching the target temperature zone by gradient heating, and oxygen is introduced into the furnace during the sintering process (oxygen concentration 95% and above), and then the pre-lithiated intermediate is rapidly transferred into a cold storage box for rapid cooling, the temperature in the cold storage box is -5 ℃, and the cooling is completed after 1 hour of storage, to obtain the cooled process sample A;

[0101] Step two: the process sample A is discharged from the cooling device through the weighing system and introduced into a rotary furnace at room temperature, the rotary furnace is rotated at a speed of 10 r / min for 15 min until the material is uniformly dispersed, then the rotary furnace is continuously rotated and a certain amount of tetrabutyl orthosilicate (Si mass ratio 1000 ppm) is sprayed into the furnace through the multi-directional spraying system of the rotary furnace, the spraying is intermittent, the duration is 1 h, and the rotary furnace is continuously rotated for 40 min after the spraying is completed, the rotary furnace is opened and the temperature is increased to 180 ℃, and then dried for 5 h, to obtain the process sample B coated with SiO2 on the surface;

[0102] Step 3: Process sample B is transferred to the weighing system through the rotary kiln discharge port, and the material is discharged into the roller furnace. Under an oxygen atmosphere (oxygen concentration is 95% or above), it is directly placed in the target temperature zone at 850°C for 10 hours for calcination and crystallization. Finally, it is cooled in the furnace cooling zone and discharged from the furnace to obtain the single crystal positive electrode material matrix C;

[0103] Step 4: After the single crystal positive electrode material matrix C is crushed and gas-powdered, it is coated with B2O3 (B mass proportion is 1500ppm) for the second time, and the mixture is coated with a high-efficiency mixer and mixed at a high speed of 300r / min for 30min. The dry package is put into a bowl and put into a roller furnace. In an oxygen atmosphere (oxygen concentration is 95% or above), it reaches the target temperature zone through a gradient heating zone and is sintered at 500℃ for 6h. Finally, it is cooled in the furnace cooling zone and taken out of the furnace to obtain a pre-finished product D.

[0104] After the pre-finished product D enters the packaging system, it is batch mixed, screened, and demagnetized, and then enters the customized anti-static device. The material after anti-static is the finished single crystal positive electrode material E, which is then unloaded through the weighing system and entered into the packaging bag for sealing and packaging.

[0105] Example 5

[0106] The steps for preparing the single crystal positive electrode material of this embodiment are as follows:

[0107] Step 1: Weigh LiOH·H2O and Ni in a molar ratio of 1.05:1 0.8 Mn 0.2 (OH)2 and Nb2O5 (wherein Nb accounts for 3000ppm by mass) are placed together in a high-efficiency mixer and mixed at a high speed of 300r / min for 30min to obtain a high-mix material; the high-mix material is placed in a sagger and placed in a roller furnace, and after the temperature reaches the target temperature zone through gradient heating, it is sintered at 800℃ for 4h, and oxygen (oxygen concentration is 95% and above) is introduced into the furnace during the sintering process. After the sintering time is completed, a pre-lithiation intermediate is obtained, and then the high-temperature pre-lithiation intermediate is rapidly transferred to an insulated box with refrigeration-assisted cooling for quenching. The temperature in the insulated box is -5℃, and the cooling is completed after insulation for 1 hour to obtain a cooled process sample A;

[0108] Step 2: Process sample A is fed into a rotary kiln at room temperature through a weighing system via a discharge port of a cooling device. The rotary kiln is rotated at a speed of 10 r / min for 15 min until the material is evenly dispersed. The rotary kiln is then continuously rotated and a fixed amount of Ca(OH)2 (Ca mass percentage 5000 ppm) using ethanol as a medium is sprayed into the kiln through a multi-directional spraying system customized for the rotary kiln. The spraying is intermittent and lasts for 1 h. After the spraying is completed, the rotary kiln is continuously rotated for 50 min to mix the mixture evenly. The exhaust port of the rotary kiln is opened and the temperature of the rotary kiln is raised to 180°C. The kiln is dried for 6 h to obtain a process sample B with a surface evenly coated with CaO.

[0109] Step three: the process sample B is transferred into the weighing system through the rotary furnace discharge port, and then is discharged into a bowl and enters the roller furnace, and is directly heated to a target temperature of 880°C under an oxygen atmosphere (oxygen concentration of 95% or more) for calcination and crystallization for 10 hours. Finally, the furnace cooling zone is used for furnace cooling and cooling out of the furnace to obtain a single-crystal cathode material base C;

[0110] Step four: after the single-crystal cathode material base C is crushed and gasified, it is coated with Al2O3 (Al mass ratio of 2000ppm), and the high-efficiency mixer is used for coating and mixing at a speed of 300r / min for 30 minutes. The dry coated material is then discharged into a bowl and enters the roller furnace, and is sintered at 600°C for 6 hours after reaching the target temperature zone through the gradient heating zone under an oxygen atmosphere (oxygen concentration of 95% or more). Finally, the furnace cooling zone is used for furnace cooling and cooling out of the furnace to obtain a pre-product D.

[0111] After the pre-product D enters the packaging system, it is batch mixed, sieved, and de-magnetized, and then enters the customized electrostatic removal device. The material after electrostatic removal is the single-crystal cathode material finished product E. After weighing, the material is discharged into a packaging bag for sealing and packaging.

[0112] Comparative example

[0113] A commercially available conventional NCM523 single-crystal cathode material is used as a control.

[0114] Test:

[0115] 1) The single-crystal cathode material prepared in Example 1 is subjected to XRD testing, and the results are shown in Figure 1 . As can be seen from Figure 1 , compared with the comparative example, the peak position and peak intensity of the two curves have no obvious difference. The peak intensity ratio of the (003) and (104) peaks in the curve of Example 1 is ≥1.2, indicating that the degree of lithium and nickel mixing in the cathode material is low. The (006 / 012) and (018 / 110) peaks are obviously split, indicating that the cathode material has a good layered structure and high crystallinity, and the synthesized sample has high purity and no impurity phase.

[0116] 2) The single-crystal cathode material prepared in Example 1 is subjected to scanning electron microscopy (SEM) testing, and the results are shown in Figures 2 to 5 . As can be seen from Figure 2 , the pre-lithiated intermediate prepared in Example 1 is a non-spherical agglomerate morphology of partially disintegrated primary particles; as can be seen from Figure 3 , the process sample A prepared in Example 1 is a state of disintegrated primary particles, which retains the particle size and morphology of the pre-lithiated intermediate primary particles; as can be seen from Figure 4 , the base C prepared in Example 1 is a single particle with a spherical or spherical-like single-crystal morphology with high roundness; as can be seen fromFigure 5 It can be seen that the finished product sample E prepared in Example 1 is a single particle or aggregate with spherical or spherical-like single crystal morphology with high roundness, and the surface has a smooth full coverage coating layer; from Figure 6 It can be seen that the material of the comparative example is irregular polygonal morphology with sharp corner contact points.

[0117] 3) The single crystal positive electrode materials prepared in Examples 1-5 and the single crystal positive electrode materials of the comparative example were subjected to electrochemical performance tests, and the results are shown in Figure 7 , Figure 8 and Table 1. Figure 7 Figures are the first charge-discharge curves of 2032 button cells made of the single crystal positive electrode materials obtained in Example 1 and the single crystal positive electrode materials of the comparative example at room temperature, current density 0.2C, voltage 3.0V-4.5V. Figure 8 Figures are the charge-discharge cycle curves of 2032 button cells made of the single crystal positive electrode materials obtained in Example 1 and the single crystal positive electrode materials of the comparative example at room temperature, current density 1C, voltage 3.0V-4.5V. The electrochemical performance test method is as follows: the single crystal positive electrode material prepared in Example 1 or the single crystal positive electrode material of the comparative example is mixed uniformly with acetylene black and polyvinylidene fluoride (PVDF) in a mass ratio of 8:1:1 in an appropriate amount of N-methyl pyrrolidone (NMP) solution, and then coated on an aluminum foil to prepare a positive electrode sheet; the negative electrode sheet uses lithium sheet, and a separator and electrolyte are added, wherein the electrolyte is a 1 mol / L LiPF6 solution, and the solvent is a mixture of EC, DEC and DMC, and the volume ratio of EC, DEC and DMC is 1:1:1. A button cell of model 2032 is assembled in an argon-filled glove box. The test is performed on a LAND battery tester, the current density is 0.2C, 1.0C, the test voltage range is 3.0V-4.5V, and the test temperature is room temperature 25℃.

[0118] 4) The single crystal positive electrode materials prepared in Examples 1-5 and the single crystal positive electrode materials of the comparative example were subjected to rest angle and flowability tests, and the results are shown in Table 2.

[0119] 5) The single crystal positive electrode materials prepared in Examples 1-5 and the single crystal positive electrode materials of the comparative example were subjected to moisture absorption tests, and the results are shown in Table 3.

[0120] Table 1 Electrochemical performance test results

[0121]

[0122] From Figure 7 and Table 1, it can be seen that the single crystal positive electrode material prepared in Example 1 has a higher first discharge capacity than the comparative material, and the first efficiency is also higher. Figure 8It can be seen that the cycle retention rate of the single-crystal positive electrode material prepared in Example 1 is also higher than that of the comparative material, and the single-crystal positive electrode material prepared in the application has more excellent electrochemical performance and better cycle life.

[0123] Table 2 Rest angle and Karl flow index test results

[0124]

[0125] As can be seen from Table 2, the single-crystal positive electrode material prepared in Examples 1-5 has a lower rest angle and a higher Karl flow index than the comparative material, indicating that it has higher flowability. By comparing the initial state and the state after three months of storage, the comparative material has obviously agglomerated and solidified, while the rest angle and flow index of the single-crystal positive electrode material prepared in Examples 1-5 only have slight changes, indicating that the adsorption is low and the flowability is not affected by storage.

[0126] Table 3 Hygroscopic value test results

[0127]

[0128] As can be seen from Table 3, the single-crystal positive electrode material prepared in Examples 1-5 has a lower hygroscopic value than the comparative material, indicating that the moisture adsorption on its surface is slower.

[0129] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, but not to limit it; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

[0130] The above is only the preferred embodiment of the application, and is not intended to limit the application, any modification, equivalent substitution and improvement made within the spirit and principle of the application should be included in the protection scope of the application. The above is only the preferred embodiment of the application, and is not intended to limit the application, any modification, equivalent substitution and improvement made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A method for preparing a high-fluidity lithium battery single crystal positive electrode material, characterized by: The preparation method comprises the following steps: Step 1: uniformly mix the precursor, lithium salt and modifier, heat to a temperature T1 of 750°C to 850°C in an oxygen-containing atmosphere, and sinter for a sintering time of t1 to obtain a pre-lithiated intermediate. The pre-lithiated intermediate is transferred to an environment with a temperature T2 of less than 10°C and quenched for a quenching time of t2 to obtain process sample A; the sintering time t1 is 1h to 6h, and the time t2 is 0.5h to 2h; Step 2: Place process sample A in an environment with a temperature of T3, disperse and spray the spheroidizing agent, and dry the sample to obtain process sample B with the surface evenly coated with the spheroidizing agent; the temperature T3 is -10°C to 200°C; Step 3: In an oxygen-containing atmosphere, the process sample B is placed in an environment with a temperature T4 of 850°C to 1000°C for rapid calcination and crystallization. The calcination time is t3, and after cooling, a single crystal positive electrode material matrix C is obtained. The calcination time t3 is 2h to 24h. Step 4: The single crystal cathode material substrate C is post-processed to obtain a high-fluidity lithium battery single crystal cathode material; The spheroidizing agent in step 2 is at least one of oxides, halides, carbonates, hydroxides, phosphides, borides, or organic compounds containing effective elements; the effective element in the spheroidizing agent is at least one of Mg, Si, Ca, Ba, Sc, Y, La, and Ce.

2. The method for preparing a high-fluidity lithium battery single crystal positive electrode material according to claim 1, characterized in that: The pre-lithiation intermediate in step 1 is a partially disintegrated non-spherical agglomerate composed of accumulated primary particles, wherein the primary particles are small single crystal particles with a diameter of 1.5 to 2.5 μm.

3. The method for preparing a high-fluidity lithium battery single crystal positive electrode material according to claim 1 or 2, characterized in that: In the step 1, the precursor is at least one of an oxide, hydroxide, carbonate, and organic acid salt containing an effective element, and the effective element in the precursor is nickel, cobalt, and zero, one, or more of Al, Mn, and Ti; the lithium salt is at least one of an oxide, hydroxide, carbonate, phosphate, nitrate, and organic acid salt containing lithium; the modifier is at least one of an oxide, halide, carbonate, hydroxide, phosphide, boride, and organic compound containing an effective element, and the effective element in the modifier is at least one of Al, Mn, Ti, Zr, Nb, Sr, W, B, Zn, Ta, Tl, Ga, V, Sn, Sb, Mo, Cs, Rb, Ru, In, and Ge.

4. The method for preparing a high-fluidity lithium battery single crystal positive electrode material according to claim 1 or 2, characterized in that: In the step 2, the drying temperature is 100° C. to 250° C., and the drying time is 1 hour to 20 hours.

5. The method for preparing a high-fluidity lithium battery single crystal positive electrode material according to claim 1 or 2, characterized in that: The post-processing steps in step 4 include: crushing and gas-powdering the single crystal positive electrode material matrix C, and then undergoing secondary coating and sintering or not undergoing secondary coating and sintering, and then batch mixing, screening, demagnetization and then static electricity removal to obtain the single crystal positive electrode material matrix C.

6. The method for preparing a high-fluidity lithium battery single crystal positive electrode material according to claim 5, characterized in that: The coating agent for the secondary coating is at least one of oxides, carbonates, hydroxides, phosphides, borides, halides, and organic compounds containing effective elements. The effective elements in the coating agent are at least one of Al, Mg, K, Ti, Nb, W, B, Mo, Si, Ca, Ba, C, and Fe. The secondary coating sintering temperature is 150° C. to 750° C., and the sintering time is 1 hour to 20 hours.

7. The method for preparing a high-fluidity lithium battery single crystal positive electrode material according to claim 1 or 2, characterized in that: The lithium element mole number of the lithium salt in the positive electrode material is 0.5-1.5, the effective element mole number of the precursor is 0.2-3.4, the effective element mole number of the modifier is 0.0005-0.005, the effective element mole number of the spheroidizer is 0.0005-0.005, and the effective element mole number of the coating agent is 0.0005-0.

004.

8. A high-fluidity lithium battery single crystal positive electrode material, characterized by: Obtained by the preparation method according to any one of claims 1 to 7, the chemical formula of the positive electrode material is: Li 1+n Ni x Co y M z A m O 2+w , wherein, -0.5≤n≤0.5, 0.2≤x<1, 0<y≤0.4, 0≤z≤2, 0≤m≤0.01, -0.5≤w≤2; M is zero, one or more of Al, Mn, and Ti; A is multiple of Al, Mn, Mg, Ti, Fe, Zr, Y, Ca, Nb, Sr, Sc, W, B, Ba, Zn, Ce, Ta, Tl, Ga, La, V, Sn, Sb, Si, Mo, Cs, Rb, Ru, In, Ge, K, Na, C, H, F, Cl, and P; the repose angle of the high-fluidity lithium battery single crystal positive electrode material is less than 40°, and the particle size D50 is 2.0 to 6.5 μm.

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