Preparation method of lithium ion battery powder material

Abstract

The invention provides a preparation method of a lithium ion battery powder material, which comprises the following steps: accurately controlling the molar ratio of lithium salt to manganese salt, and adding other metal oxides or metal salts as dopants to form an initial mixture; preparing the mixture into uniformly dispersed slurry, and drying the slurry to form precursor particles; the dried precursor is subjected to multi-stage hot pressing sintering, meanwhile, the sintering temperature and pressure are regulated and controlled, and the lithium ion battery powder material with the uniform morphology is synthetized, through the hot pressing sintering technology, the sintering period is effectively shortened, the production efficiency is remarkably improved, and the obtained lithium ion battery powder material is small in particle, regular in morphology, high in tap density and good in comprehensive performance. The product uniformity is excellent, the technological process is simple and efficient, and a powerful guarantee is provided for stable supply of the high-performance positive electrode material.

Description

Technical Field

[0001] This invention relates to a lithium-ion battery powder material, a preparation method thereof, and a cathode material containing lithium-ion battery powder. Background Technology

[0002] Lithium manganese oxide powder is a type of composite oxide functional powder with manganese as the core transition metal and lithium as the alkali metal. It typically ranges in appearance from brownish-black to dark black, with particle sizes in the micrometer range, and the particles are regularly spherical or near-spherical. Its crystal structure is predominantly layered or spinel-type, endowing the material with high ion mobility and three-dimensional lithium-ion channels, thus exhibiting excellent electrochemical activity.

[0003] In the current large-scale production of lithium manganese oxide powder, static sintering is commonly carried out using box furnaces or roller kilns: the material is loosely spread on saggers or pushers, slowly heated from room temperature to the sintering temperature, held at that temperature for several hours or even more than ten hours, and then naturally cooled. The entire process relies solely on heat conduction and radiation, resulting in a low heating rate, long heat transfer paths, and reaction kinetics limited by the solid-phase diffusion rate. Consequently, the process is lengthy, energy-intensive, and has slow equipment turnaround. Simultaneously, due to the lack of external forces in the sintering system, particles can only rearrange randomly under the drive of their own surface energy reduction, resulting in limited pore closure. The final powder exhibits a loose, porous structure with low tap density, making compaction difficult after loading into the cathode sheet, thus limiting the battery's volumetric energy density and cycle life. Furthermore, prolonged exposure to high temperatures can induce abnormal grain growth, component segregation, and the formation of secondary phases, further affecting material consistency and electrochemical performance. The industry urgently needs an integrated process route that can significantly shorten sintering time while improving powder density, thus balancing production efficiency, energy consumption control, and product performance. Summary of the Invention

[0004] The purpose of this invention is to propose a lithium-ion battery powder material, a preparation method, and a cathode material containing lithium-ion battery powder. The hot pressing sintering process greatly shortens the time and improves the efficiency. The material after hot pressing sintering has a small particle size and high tap density. In addition, the pressure is dynamically adjusted during the sintering process to optimize the uniformity of the product.

[0005] The objective of this invention is achieved through the following technical solution: This invention provides a method for preparing lithium-ion battery powder materials, comprising the following steps: S1 precisely controls the molar ratio of lithium salt to manganese salt and adds other metal oxides or metal salts as dopants to form an initial mixture; S2 prepares the mixture into a uniformly dispersed slurry and adds one or more of polyethylene glycol, ascorbic acid, glucose, and citric acid. The slurry particle size D50 is 0.1-500nm. S3 dries the slurry to form precursor particles with a D50 of 0.1-30 μm; S4 performs multi-stage hot pressing sintering on the dried precursor, while controlling the sintering temperature and pressure to synthesize lithium manganese oxide powder with uniform morphology and a D50 particle size of 0.1-20μm. The hot pressing sintering is divided into two stages, with different temperatures and pressures applied respectively. The powder is composed of the general formula Li x M1 y Mn 1-y O 2-z M2 z It is indicated that X, Y and Z are each such numbers: 0.9≤x≤1.1, 0<y≤0.1, 0<z≤0.05, and M1 and M2 are selected from one or more of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F or B respectively.

[0006] Preferably, the S4 hot pressing sintering adopts an atmosphere hot press. The first stage is the heating stage, with a gradient pressure of 2MPa-15MPa, and the reaction temperature is raised to the constant temperature sintering temperature. The second stage is constant temperature and pressure sintering, with a constant temperature sintering time of 1h-10h, a pressure of 5MPa-50MPa, and a sintering temperature controlled at 700°C-1000°C.

[0007] Preferably, in S2, slurry D max ≤2μm.

[0008] Preferably, the S3 drying process employs one of pyrolysis drying, freeze drying, or fluidized bed drying, and the precursor particles formed during drying are 1 < (D 90 -D 10 ) / D50<5.

[0009] Preferably, the dopant in S1 is one or more of the following: oxides, hydroxides, and sulfides of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F, or B.

[0010] Preferably, the amount of lithium salt, manganese salt, and dopant added is in a molar ratio of Li:Mn:M = 1.0 : x(0.9-0.99): 1-x.

[0011] Preferably, one or more of lithium nitrate, lithium acetate, lithium borate, lithium metaborate, and lithium difluorooxalate borate are added during process S1, and the amount added is 0.01~2% of the total weight.

[0012] Preferably, in the S2 process, 0.1-15% by weight of polyethylene glycol, sodium dodecylbenzenesulfonate, or polyacrylate is added.

[0013] On the other hand, the present invention provides a lithium-ion battery powder material, which is composed of a general formula Li x M1 y Mn 1-y O 2-z M2 z It is indicated that X, Y and Z are each of the following numbers: 0.9≤x≤1.1, 0<y≤0.1, 0<z≤0.05, and M1 and M2 are selected from one or more of the oxides, hydroxides and sulfides of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F or B.

[0014] On the other hand, the present invention provides a lithium-ion battery powder material, including the above-mentioned lithium-ion battery powder.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention effectively shortens the sintering cycle and significantly improves production efficiency through hot pressing sintering. The resulting lithium-ion battery powder particles are fine, regular in morphology, and have high tap density, exhibiting excellent product uniformity. The process is simple and efficient, with strong equipment compatibility, making it suitable for large-scale production and providing a strong guarantee for the stable supply of high-performance cathode materials. Attached Figure Description

[0016] Figure 1 This is a particle size distribution diagram of the material after conventional sintering, as shown in the comparative example of this application. Figure 2 This is a particle size distribution diagram of the material after hot pressing and sintering in Example 2 of this application; Figure 3 This is a comparative example of the SEM image of the material after conventional sintering in this application; Figure 4 This is a SEM image of the material after hot pressing and sintering in Example 2 of this application. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments.

[0018] This invention provides a method for preparing lithium-ion battery powder materials, comprising the following steps: S1 precisely controls the molar ratio of lithium salt to manganese salt and adds other metal oxides or metal salts as dopants to form an initial mixture; S2 prepares the mixture into a uniformly dispersed slurry and adds one or more of polyethylene glycol, ascorbic acid, glucose, and citric acid. The slurry particle size D50 is 0.1-500nm. S3 dries the slurry to form precursor particles with a D50 of 0.1-30 μm; S4 performs multi-stage hot pressing sintering on the dried precursor, while controlling the sintering temperature and pressure to synthesize lithium manganese oxide powder with uniform morphology and a D50 particle size of 0.1-20μm. The hot pressing sintering is divided into two stages, with different temperatures and pressures applied respectively. Powders composed of the general formula Li x M1 y Mn 1-y O 2-z M2 z It is indicated that X, Y and Z are each such numbers: 0.9≤x≤1.1, 0<y≤0.1, 0<z≤0.05, and M1 and M2 are selected from one or more of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F or B respectively.

[0019] In one embodiment of the present invention, the S4 hot pressing sintering employs an atmosphere hot press. The first stage is a heating stage with a gradient pressure of 2 MPa-15 MPa, raising the reaction temperature to a constant sintering temperature. The second stage is constant temperature and pressure sintering lasts 1-10 hours, with a pressure of 5 MPa-50 MPa and a sintering temperature controlled between 700°C and 1000°C. The temperature and pressure are dynamically adjusted during the sintering process to optimize product uniformity.

[0020] In one embodiment of the present invention, slurry D in S2 max ≤2μm.

[0021] In one embodiment of the present invention, S3 drying is performed using one of pyrolysis drying, freeze drying, or fluidized bed drying, and the precursor particles formed by drying are 1 < (D 90 -D 10 ) / D50<5.

[0022] In one embodiment of the present invention, the dopant in S1 is either CuO or SnO2. Cu²⁺ increases electronic conductivity and reduces polarization after entering the crystal lattice, while SnO2... 4 ⁺ Stabilizing the spinel framework suppresses Jahn-Teller distortion and improves cycle life. Co-doping with both can form a uniform and dense interface layer on the particle surface, reducing side reactions and balancing high rate capability and long cycle performance.

[0023] In one embodiment of the present invention, the S1 dopant is one or more of the following: oxides, hydroxides, and sulfides of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F, or B.

[0024] In one embodiment of the present invention, the amounts of lithium salt, manganese salt, and dopant added are in a molar ratio of Li:Mn:M = 1.0:x(0.9-0.99):1-x.

[0025] In one embodiment of the present invention, the amounts of lithium source, manganese source, CuO, and SnO2 added are in a molar ratio of Li:Mn:Cu:Sn = 1.0:0.95:0.025:0.025.

[0026] In one embodiment of the present invention, one or more of lithium nitrate, lithium acetate, lithium borate, lithium metaborate, and lithium difluorooxalate borate are added during process S1, with the amount added being 0.01~2% of the total weight. This provides a low-melting-point lithium-containing flux phase in the early stage of the solid-state reaction, reduces the sintering activation energy, compensates for lithium volatilization loss at high temperatures, and stabilizes the stoichiometry and crystal structure of the final product.

[0027] In one embodiment of the present invention, 0.1-15% by weight of polyethylene glycol, sodium dodecylbenzenesulfonate, or polyacrylate is added during process S2.

[0028] In one embodiment of the present invention, polyethylene glycol (PEG) accounting for 9% of the total weight is added during process S2 to ensure the uniformity and stability of the slurry dispersion. After the addition of PEG, the long-chain PEG molecules are rapidly adsorbed onto the powder surface to form a steric hindrance layer, effectively preventing particle agglomeration. At the same time, its hydrophilic skeleton improves the compatibility of the slurry with deionized water and reduces viscosity fluctuations, so that the slurry remains uniformly dispersed during long-term grinding, conveying and spraying, without sedimentation or secondary agglomeration, providing a stable foundation for obtaining spherical, narrow-distribution precursor particles in the future.

[0029] Furthermore, this invention provides a lithium-ion battery powder material composed of the general formula Li x M1 y Mn 1-y O 2-z M2 z It is indicated that X, Y and Z are each of the following numbers: 0.9≤x≤1.1, 0<y≤0.1, 0<z≤0.05, and M1 and M2 are selected from one or more of the oxides, hydroxides and sulfides of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F or B.

[0030] Furthermore, the present invention provides a lithium-ion battery powder material, including the above-mentioned lithium-ion battery powder.

[0031] The present invention will be further described below using examples.

[0032] Example 1 Weigh the raw materials S1, LiOH, Mn(NO3)2, TiO2, and SnO2 in the molar ratio Li:Mn:Ti:Sn = 1.0 : 0.95 : 0.025 : 0.025, add the above raw materials to the mixer, and mix thoroughly to form the initial mixture; S2 adds the mixture to the feeding tank, along with an appropriate amount of deionized water and 9% polyethylene glycol by weight. The mixture is stirred to form a uniformly dispersed slurry, ensuring that the slurry D50 particle size is 155 nm. max It is 1.95 μm; S3 dries the slurry to form spherical precursor particles with uniform particle size and good flowability. The dried particles have a D50 particle size of 5.5 micrometers and a (D90-D10) / D50 ratio of 2.05. S4 feeds the dried precursor particles into an atmosphere hot press. The first stage of heating lasts 50 minutes with a gradient pressure of 15 MPa, and the reaction temperature reaches 1000°C. The second stage involves isothermal sintering for 4.5 hours at a pressure of 50 MPa and a sintering temperature controlled at 800°C. Through heating and pressurization, uniform lithium manganese oxide powder is synthesized, with a measured D50 particle size of 7.5 micrometers and a spherical shape.

[0033] Example 2 Weigh the raw materials S1 LiOH, Mn(NO3)2, CrO2, and MgO in a molar ratio of Li:Mn:Cr:Mg = 1.0:0.95:0.025:0.025, add 1 wt% lithium nitrate, and add the above raw materials to the mixer. Mix thoroughly to form an initial mixture. S2 adds the mixture to the feeding tank, along with an appropriate amount of deionized water and 9% polyethylene glycol by weight. The mixture is stirred to form a uniformly dispersed slurry, ensuring the slurry D50 particle size is within 155 nm. max =2μm; S3 dries the slurry to form spherical precursor particles with uniform particle size and good flowability. The dried particles have a D50 particle size of 5.5 micrometers and a (D90-D10) / D50 ratio of 2.5. S4 feeds the dried precursor particles into an atmosphere hot press. The first stage involves heating for 50 minutes with a gradient pressure of 15 MPa, raising the reaction temperature to 1000°C. The second stage involves isothermal sintering for 4.5 hours at a pressure of 50 MPa, controlled at 800°C. Through heating and pressurization, uniformly shaped lithium manganese oxide powder is synthesized, with a measured D50 particle size of 7.5 micrometers and spherical shape. .

[0034] Example 3 Compared to Example 2, the spray-dried precursor particles were fed into an atmospheric hot press. The first stage of heating time is 30 minutes, the gradient pressure during the heating stage is 10 MPa, and the reaction temperature rises to 950 °C. The second stage isothermal and pressure sintering, with an isothermal sintering time of 3.0 hours, an isothermal sintering pressure of 40 MPa, and a sintering temperature controlled at 820 °C. Lithium manganese oxide powder with uniform morphology was synthesized by heating and pressurizing. The D50 particle size was measured to be 7.5 micrometers, and the particles were spherical.

[0035] The measured tap density was greater than 2.35 g cm⁻³, and the hot pressing sintering cycle was shortened while maintaining the particle size.

[0036] Comparative Example Compared to Example 3, static sintering was used, with the temperature increased to 950 °C in 30 min, held for 3 h, and then naturally cooled and demolded. The particle size was measured, with a D50 of 15 µm. The particle morphology was irregular with rounded edges, and the tap density was 1.75 g cm⁻³. The structure was loose and porous, and voids remained after tapping.

[0037] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for preparing a lithium ion battery powder material, the method comprising: The method comprises the following steps: ​ S1 precisely control the molar ratio of lithium salt and manganese salt, and add other metal oxides or metal salts as dopants to form an initial mixture; S2 make the mixture into a uniformly dispersed slurry, and add one or more of polyethylene glycol, ascorbic acid, glucose, and citric acid, wherein the particle size D50 of the slurry is 0.1-500 nm; S3 dry the slurry to form precursor particles, wherein the D50 is 0.1-30 μm; S4 perform multi-stage hot-press sintering on the dried precursor, while adjusting the sintering temperature and pressure, to synthesize lithium-manganese oxide powder with uniform morphology, wherein the D50 particle size is 0.1-20 μm, and the hot-press sintering is divided into two stages, in which different temperatures and pressures are applied respectively; The powder is composed of a general formula Li x M1 y Mn 1-y O 2-z M2 z wherein X, Y and Z are each a number such that 0.9≤x≤1.1, 0 M1, M2 are each selected from one or more of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F or B.

2. The method for preparing lithium-ion battery powder material according to claim 1, characterized in that, The hot-press sintering in S4 is performed by using an atmosphere hot-press machine, in the first stage, the gradient pressure in the heating stage is 2 MPa-15 MPa, and the reaction temperature is raised to the constant temperature sintering temperature; in the second stage, the constant temperature sintering time is 1 h-10 h, the pressure in the constant temperature sintering stage is 5 MPa-50 MPa, and the sintering temperature is controlled in the range of 700°C-1000°C.

3. The method of claim 1, wherein the lithium ion battery powder material is prepared by the steps of: wherein slurry D in S2 max ≤ 2 μm. ​ 4. The method for preparing lithium-ion battery powder material according to claim 1, characterized in that, wherein S3 drying is one of pyrolysis drying, freeze drying, fluidized bed drying, and the precursor particles 1 < (D 90 -D 10 ) / D50 < 5.

5. The method for preparing lithium-ion battery powder material according to claim 1, characterized in that, The dopant in S1 is one or more of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F, or B oxides, hydroxides, or sulfides.

6. The method for preparing lithium-ion battery powder material according to claim 5, characterized in that, The lithium salt, the manganese salt, and the dopant are added in a molar ratio of Li:Mn:M = 1.0 : x (0.9-0.99) : 1-x.

7. The method for preparing lithium-ion battery powder material according to claim 1, characterized in that, In S1, one or more of lithium nitrate, lithium acetate, lithium borate, lithium metaborate, and lithium difluoro oxalate borate is added, and the amount added is 0.01-2% of the total weight.

8. The method for preparing lithium-ion battery powder material according to claim 1, characterized in that, In S2, 0.1-15% of polyethylene glycol, or sodium dodecylbenzenesulfonate, or polyacrylate is added.

9. The lithium ion battery powder material prepared according to the method of claims 1-8, wherein, consists of the general formula Li x M1 y Mn 1-y O 2-z M2 z wherein X, Y and Z are each a number such that 0.9≤x≤1.1, 0 M1, M2 are each selected from one or more of Mg, Nb, Cr, Ti, Al, Sn, Fe, Co, Ni, Na, F or B oxides, hydroxides, sulfides.

10. A lithium ion battery powder positive electrode material, comprising the lithium ion battery powder material according to claim 9.

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