A composite lithium-ion battery cathode material with a mother-daughter spherical morphology and its preparation method

Abstract

This invention discloses a composite lithium-ion battery cathode material with a mother-daughter spherical morphology and its preparation method. First, different raw materials are mixed using different mixing methods, and then calcined to generate "daughter spheres." Next, the composite lithium-ion battery cathode material with a mother-daughter spherical morphology is generated through wet grinding, wet mixing, and centrifugal spray drying granulation. The particle size of the "daughter spheres" is controllable during generation, filling the interior of the "mother sphere." The gaps between the solid "daughter spheres" facilitate electrolyte penetration and provide ample space for lithium-ion diffusion, effectively improving the rate performance and high / low temperature performance of the composite material. This invention's method is simple, low-cost, and perfectly solves the shortcomings of different types of lithium-ion battery cathode materials, such as low initial coulombic efficiency, cycle capacity decay, and rapid voltage decay. The lithium-ion battery composite cathode material prepared using this method combines the advantages of both mother and daughter materials, exhibiting higher compatibility.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery cathode materials, specifically to a composite lithium-ion battery cathode material with a mother-daughter morphology and its preparation method. Background Technology

[0002] Lithium-ion batteries, with their advantages of high specific energy, no memory effect, and long cycle life, are hailed as the most promising secondary power source and have become the mainstream power source for portable electronic products such as mobile phones and laptops. Meanwhile, in the field of power batteries, high energy density and rapid charge / discharge capabilities are particularly important indicators. However, current power lithium-ion batteries can no longer meet the rapidly growing market demand. The energy density of a battery primarily refers to the energy density of the electrode materials. Currently commercially available cathode materials include lithium cobalt oxide, lithium manganese oxide, ternary materials, and lithium iron phosphate. These materials each have their own problems in terms of energy density, cycle performance, safety, and cost. Therefore, further development is needed.

[0003] Because existing lithium-ion battery cathode materials have drawbacks such as low initial coulombic efficiency, poor rate performance, and rapid cycle decay, people usually use methods such as coating, doping, and composite materials to improve the electrochemical performance of the materials. Summary of the Invention

[0004] To address the shortcomings of existing lithium-ion battery cathode materials and the incompatibility of directly mixing different cathode materials, this invention proposes a method for preparing a composite lithium-ion battery cathode material with a mother-daughter sphere morphology and its product. The aim is to prepare a lithium-ion battery cathode material with a unique "mother-daughter sphere" structure, where the particle size of the internal "daughter spheres" is controllable and the external "mother sphere" has a complete morphology. This invention's method is simple, low-cost, and perfectly solves the problems of low initial coulombic efficiency, cycle capacity decay, and rapid voltage decay associated with different types of lithium-ion battery cathode materials. The composite lithium-ion battery cathode material prepared using this method combines the advantages of both "mother" and "daughter" materials, exhibiting higher compatibility.

[0005] This invention provides a composite lithium-ion battery cathode material with a mother-daughter spherical morphology, characterized in that the cathode material comprises daughter spheres and a mother sphere, with the daughter spheres filling the interior of the mother sphere, the inner daughter spheres being tightly bonded to the outer mother sphere, and gaps existing between multiple daughter spheres; the daughter spheres are solid small particles, and the mother sphere is a hollow large particle; the particle size of the inner daughter spheres of the cathode material is adjustable, and the outer mother sphere has a complete morphology; the daughter spheres are one or more lithium-ion battery cathode materials, and the mother sphere is one lithium-ion battery cathode material.

[0006] The lithium-ion battery cathode materials used in the daughter and mother spheres include, but are not limited to, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium-ion battery binary materials, lithium-ion battery ternary materials, lithium-ion battery multi-element materials, lithium-ion battery lithium-rich manganese-based cathode materials, lithium iron phosphate, and lithium manganese iron phosphate.

[0007] Furthermore, the particle size D50 of the daughter ball is ≤10μm, and the particle size D50 of the mother ball is ≥15μm.

[0008] Furthermore, the molar percentage of the sub-sphere in the composite lithium-ion battery cathode material with the mother-daughter sphere morphology is 20%-80%.

[0009] This invention also provides a method for preparing a composite lithium-ion battery cathode material with a mother-daughter spherical morphology, comprising the following steps:

[0010] (1) Preparation of sub-spheres: Weigh various raw materials in stoichiometric ratio according to the chemical formula of the sub-spheres of the composite lithium-ion battery cathode material with the morphology of the mother and daughter spheres, mix the various raw materials in a certain way under the action of appropriate additives, and sinter to obtain sub-spheres;

[0011] The raw materials for preparing the sub-spheres can be one or more of the following: salts, oxides, hydroxides, etc. containing metal elements; the mixing method of the raw materials can be one or more of the following: wet co-precipitation, solid-phase method, wet grinding, spray granulation, sol-gel method, hydrothermal method, etc.; among them, wet grinding can be planetary ball milling or sand milling; the additives used in preparing the sub-spheres can be one or more of the following: ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, citric acid, PEG, PAM, PAN, CMC, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, polyvinylpyrrolidone; the sintering process can be carried out by one or more of the following: oxygen, air, argon, nitrogen, hydrogen, etc., depending on the material.

[0012] (2) Preparation of mother-daughter spheres: Weigh the raw materials in stoichiometric ratio according to the chemical formula of the mother sphere of the composite lithium-ion battery cathode material with the morphology of the mother-daughter spheres, wet mix the various raw materials, add a certain amount of dispersant, and wet grind after complete dispersion. After grinding, add the daughter spheres prepared in the first step to the slurry and mix evenly. Then perform centrifugal spray drying and sintering to obtain the composite lithium-ion battery cathode material with the morphology of the mother-daughter spheres.

[0013] When preparing the mother ball, the raw material can be one or more of the following: salts, oxides, hydroxides, etc. containing metal elements; the solvent in the wet mixing process is one or more of the following: ethanol, deionized water, etc.; the mixing method is one or more of the following: mechanical stirring, ultrasonic dispersion, magnetic stirring, etc.; the wet grinding is one or more of the following: planetary ball mill or sand mill.

[0014] The dispersant used in the wet mixing process is one or more of PEG, PAM, PAN, CMC, cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, and polyvinylpyrrolidone; the solid content of the slurry during the wet mixing process is 20% to 60%; the final particle size D50 of the slurry after wet grinding is below 500 nm; the particle size D50 of the spray-dried granulation is above 15 μm; and the sintering process can introduce one or more of oxygen, air, argon, nitrogen, and hydrogen, depending on the material.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] (1) This invention divides the preparation process of the composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology into two parts: the "daughter spheres" and the "mother-daughter spheres" of the composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology. First, different raw materials are mixed using different mixing methods, and then calcined to generate "daughter spheres"; then, the composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology is generated by wet grinding, wet mixing, and centrifugal spray drying granulation. The particle size of the "daughter spheres" can be controlled during the generation process. They fill the interior of the "mother spheres", and the gaps between the solid "daughter spheres" are conducive to electrolyte penetration, providing as much space as possible for lithium-ion diffusion, effectively improving the rate performance and high and low temperature performance of the composite material. Furthermore, the "mother sphere" is a hollow large particle, which shortens the lithium-ion insertion and extraction path, making it more conducive to the insertion and extraction of lithium ions and improving the cycle efficiency of the material. In addition, the "daughter sphere" inside the composite lithium-ion battery cathode material with the "daughter sphere" morphology is tightly bonded to the outer hollow "mother sphere", making it less prone to crushing and with high tap density. It can also buffer the structural strain during the charging and discharging process, effectively improving the compaction density and energy density.

[0017] (2) The composite lithium-ion battery cathode material with the “mother-daughter sphere” morphology synthesized by the present invention has high compatibility and can be used to composite different types of cathode materials, perfectly solving the problem that different types of cathode materials are difficult to composite. It can also give full play to the advantages of each material itself, suppress the disadvantages, and achieve a balance between performance and cost, and has market application prospects.

[0018] (3) The preparation method of the composite lithium-ion battery cathode material with the "mother-daughter sphere" morphology provided by the present invention is simple to operate, the process is clear, the cost is low, and it is suitable for large-scale industrial production. Attached Figure Description

[0019] Figure 1 The image shown is a scanning electron microscope (SEM) image of the composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology prepared in Example 1.

[0020] Figure 2The figure shows the first charge-discharge curves of the cathode materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 at 0.1C.

[0021] Figure 3 The figure shows the rate performance curves of the cathode materials prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0022] Figure 4 The figure shows the cycling performance of the cathode materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 after 100 cycles at 1C. Detailed Implementation

[0023] The present invention will now be described in detail through specific embodiments. Example 1

[0024] ① "Sub-spheres": Manganese dioxide and nickel hydroxide raw materials were weighed according to the stoichiometric ratio Mn:Ni=3:1, mixed with deionized water, and sodium dodecylbenzenesulfonate dispersant (3‰ of the raw material mass) was added. After complete dispersion, the mixture was transferred to a sand mill for grinding. When the particle size D50 of the slurry decreased to below 500nm, it was subjected to air spray drying granulation to obtain precursor material with a particle size D50=5μm. The dried material was mixed evenly with lithium carbonate according to the stoichiometric ratio and sintered in air atmosphere: held at 450℃ for 6h and at 900℃ for 12h to obtain Li 1.2 Ni 0.2 Mn 0.6 The "daughter spheres" in the composite lithium-ion battery cathode material with an O2 "mother-daughter sphere" morphology.

[0025] ② "Mother-Daughter Spheres": "Mother spheres" are prepared according to a molar percentage of 50% for the "daughter spheres" of the composite lithium-ion battery cathode material. Manganese dioxide, nickel hydroxide, and cobalt tetroxide are weighed according to a stoichiometric ratio of Mn:Ni:Co = 0.54:0.13:0.13, mixed with deionized water, and 3‰ (by weight) of CMC dispersant is added. After complete dispersion, the mixture is transferred to a sand mill for grinding. Once the slurry particle size D50 drops below 500 nm, the "daughter spheres" of the composite lithium-ion battery cathode material Li... 1.2 Ni 0.2 Mn 0.6 O2 was added to the slurry and mixed evenly, then centrifugally spray-dried and granulated to obtain a precursor material with a particle size D50 = 30 μm. The dried material was then mixed evenly with lithium carbonate in a stoichiometric ratio and sintered in air: held at 450℃ for 6 h and at 900℃ for 12 h, yielding a 0.5Li carbonate. 1.2 Ni 0.2 Mn 0.6 O2·0.5Li 1.2 Mn 0.54Ni 0.13 Co 0.13 A composite lithium-ion battery cathode material with an O2 "mother-daughter sphere" morphology. Example 2

[0026] ① "Sub-spheres": Nickel sulfate, manganese sulfate, and cobalt sulfate were weighed according to the stoichiometric ratio Ni:Mn:Co=3:1:1. After being thoroughly mixed with deionized water, they were added to the reactor along with ammonia and sodium hydroxide solution. The mixture was stirred continuously during the reaction. After the addition was complete, the mixture was aged for another 8 hours. The slurry was then filtered, washed, and dried to obtain a precursor material with a particle size D50 of approximately 8 μm. The dried material was then thoroughly mixed with lithium carbonate according to the stoichiometric ratio and sintered in air: at 450℃ for 5 hours and then at 750℃ for 10 hours, yielding a precursor material with the chemical formula LiNi. 0.6 Co 0.2 Mn 0.2 The "daughter spheres" in the composite lithium-ion battery cathode material with an O2 "mother-daughter sphere" morphology.

[0027] ② "Mother-Daughter Balls": "Mother balls" are prepared according to a molar percentage of 20% for the "daughter balls" of the composite lithium-ion battery cathode material. Iron phosphate, lithium carbonate, and anhydrous glucose are weighed according to a stoichiometric ratio of Fe:Li:C = 1:1.05:0.8. These are mixed with deionized water at a solid content of 50%, and 2‰ of the raw material mass of polyvinylpyrrolidone dispersant is added. After complete dispersion, the mixture is transferred to a sand mill for grinding. Once the slurry particle size D50 drops below 300 nm, the "daughter balls" of the composite lithium-ion battery cathode material LiNi are formed. 0.6 Co 0.2 Mn 0.2 O2 was added to the slurry and mixed evenly, then centrifugally spray-dried and granulated to obtain a precursor material with a particle size D50 = 25 μm. The dried material was then sintered under a nitrogen atmosphere: held at 350℃ for 2 hours and at 650℃ for 12 hours to obtain a precursor material with the chemical formula 0.2LiNi. 0.6 Co 0.2 Mn 0.2 O2·0.8LiFePO4 composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology. Example 3

[0028] ① "Sub-spheres": Lithium carbonate, manganese dioxide, and nickel hydroxide were weighed according to the stoichiometric ratio Li:Mn:Ni = 2:1:1, mixed evenly using a planetary ball mill, and sintered in air atmosphere: held at 450℃ for 6 hours and at 720℃ for 12 hours to obtain LiMn 0.5 Ni 0.5 The "daughter spheres" in the composite lithium-ion battery cathode material with an O2 "mother-daughter sphere" morphology.

[0029] ② "Mother-Daughter Spheres": "Mother spheres" are prepared according to a molar percentage of 70% for the "daughter spheres" of the composite lithium-ion battery cathode material. Manganese dioxide, nickel hydroxide, and cobalt tetroxide are weighed according to a stoichiometric ratio of Mn:Ni:Co = 1:1:1. These are mixed with deionized water at a solid content of 30%, and 1.5‰ of the raw material mass of PAM dispersant is added. After complete dispersion, the mixture is transferred to a sand mill for grinding. Once the slurry particle size D50 drops below 350 nm, the "daughter spheres" of the composite lithium-ion battery cathode material LiMn are then ground. 0.5 Ni 0.5 O2 was added to the slurry and mixed evenly, then centrifugally spray-dried and granulated to obtain a precursor material with a particle size D50 = 35 μm. The dried material was then mixed evenly with lithium carbonate in a stoichiometric ratio and sintered in air: held at 450℃ for 6 h and at 750℃ for 12 h, yielding a precursor material with the chemical formula 0.7LiMn. 0.5 Ni 0.5 O2·0.3LiMn 0.33 Ni 0.33 Co 0.33 A composite lithium-ion battery cathode material with an O2 "mother-daughter sphere" morphology. Example 4

[0030] ① "Sub-spheres": Lithium acetate, manganese acetate, nickel acetate, and cobalt acetate were weighed according to the stoichiometric ratio Li:Ni:Mn:Co = 1.05:0.8:0.1:0.1, dissolved in deionized water to form a solution, and stirred continuously in a 70°C water bath. Citric acid and sodium dodecylbenzenesulfonate were added as ligands and templates until a gel was formed. The resulting gel was vacuum dried at 120°C for 10 hours and then sintered in an oxygen atmosphere: held at 450°C for 6 hours and at 750°C for 12 hours to obtain LiNi 0.8 Co 0.1 Mn 0.1 The "daughter spheres" in the composite lithium-ion battery cathode material with an O2 "mother-daughter sphere" morphology.

[0031] ② "Mother-Daughter Balls": "Mother balls" are prepared according to a molar percentage of 40% for the "daughter balls" of the composite lithium-ion battery cathode material. Manganese phosphate, iron phosphate, lithium carbonate, and anhydrous glucose are weighed according to a stoichiometric ratio of Mn:Fe:Li:C = 0.6:0.4:1.05:0.8. These are mixed with deionized water at a solid content of 40%, and 2‰ of the raw material mass of PAN dispersant is added. After complete dispersion, the mixture is transferred to a sand mill for grinding. Once the slurry particle size D50 drops below 250 nm, the "daughter balls" of the composite lithium-ion battery cathode material LiNi are then added. 0.8 Co 0.1 Mn0.1 O2 was added to the slurry and mixed evenly, then centrifugally spray-dried and granulated to obtain a precursor material with a particle size D50 = 20 μm. The dried material was then sintered under a nitrogen atmosphere: held at 350℃ for 2 hours and at 750℃ for 10 hours to obtain a precursor material with the chemical formula 0.4LiNi. 0.8 Co 0.1 Mn 0.1 O2·0.6LiMn 0.6 Fe 0.4 A composite lithium-ion battery cathode material with a PO4 “mother-daughter sphere” morphology. Example 5

[0032] ① "Daughter Spheres": Manganese dioxide and nickel hydroxide raw materials were weighed according to a stoichiometric ratio of Mn:Ni = 1:1. First, manganese dioxide was mixed with deionized water at a solid content of 40%, and PEG dispersant at 1‰ of the raw material mass was added. After complete dispersion, the mixture was transferred to a sand mill for grinding. Once the slurry particle size D50 decreased to below 400 nm, it was subjected to air spray drying granulation to obtain a precursor material with a particle size D50 = 6 μm. The dried material was then mixed uniformly with lithium carbonate according to a stoichiometric ratio and sintered in air: held at 450℃ for 6 hours and at 700℃ for 12 hours, yielding "daughter sphere a" in a composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology and the chemical formula LiMnO2. Nickel hydroxide was then processed using the same steps to obtain "daughter sphere b" in a composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology and the chemical formula LiNiO2.

[0033] ② "Mother-Daughter Spheres": "Mother spheres" are prepared according to the principle that the "daughter spheres" of the composite lithium-ion battery cathode material account for 80% of the total molar percentage of the composite lithium-ion battery cathode material. Manganese dioxide, nickel hydroxide, and cobalt tetroxide are weighed according to the stoichiometric ratio Mn:Ni:Co=1:1:1, mixed with deionized water at a solid content of 30%, and 1.5‰ of PAM dispersant is added. After complete dispersion, the mixture is transferred to a sand mill for grinding. When the particle size D50 of the slurry is reduced to below 350nm, the composite lithium-ion battery cathode materials LiMnO2 and LiNiO2 of the "daughter spheres" are added to the slurry and mixed evenly. Then, the mixture is centrifugally spray-dried and granulated to obtain precursor material with a particle size D50=35μm. The dried material was mixed uniformly with lithium carbonate in a stoichiometric ratio and then sintered in air: held at 450℃ for 6 hours and at 750℃ for 12 hours, yielding the chemical formula [0.1LiMnO2·0.1LiNiO2]·0.8LiMn 0.33 Ni 0.33 Co 0.33 A composite lithium-ion battery cathode material with an O2 "mother-daughter sphere" morphology.

[0034] Comparative Example 1

[0035] Manganese dioxide and nickel hydroxide raw materials were weighed according to a stoichiometric ratio of Mn:Ni = 0.6:0.2, mixed with deionized water at a solid content of 25%, and PAM dispersant (3‰ of the raw material mass) was added. After complete dispersion, the mixture was transferred to a sand mill for grinding. Once the slurry particle size D50 decreased to below 500 nm, it was subjected to air-jet spray drying granulation to obtain a precursor material with a particle size D50 = 5 μm. The dried material was then mixed uniformly with lithium carbonate according to the stoichiometric ratio and sintered in air: held at 450℃ for 6 h and at 900℃ for 12 h to obtain Li 1.2 Ni 0.2 Mn 0.6 O2 is the positive electrode material for lithium-ion batteries.

[0036] Comparative Example 2

[0037] Manganese dioxide, nickel hydroxide, and cobalt tetroxide were weighed according to a stoichiometric ratio of Mn:Ni:Co = 0.54:0.13:0.13. They were mixed with deionized water at a solid content of 25%, and PAM dispersant (2‰ of the raw material mass) was added. After complete dispersion, the mixture was transferred to a sand mill for grinding. Once the slurry particle size D50 decreased to below 300 nm, centrifugal spray drying was performed to granulate the slurry, yielding a precursor material with a particle size D50 = 30 μm. The dried material was then mixed uniformly with lithium carbonate according to the stoichiometric ratio and sintered in air: at 450℃ for 6 hours and at 900℃ for 12 hours. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 is the positive electrode material for lithium-ion batteries.

[0038] Figure 1 The image shows the 0.5Li composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology prepared in Example 1. 1.2 Ni 0.2 Mn 0.6 O2·0.5Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 scanning electron microscope image. The image shows that the surface of the "mother sphere" is smooth, with a hollow internal structure, while the "daughter spheres" are solid small particles. This composite lithium-ion battery cathode material with its "mother-daughter sphere" morphology exhibits a tight bond between the internal "daughter spheres" and the outer hollow "mother sphere," resulting in dense particle packing. This arrangement is beneficial for improving the material's compaction density and volumetric energy density. Gaps exist between the solid "daughter spheres," facilitating electrolyte penetration and providing space for lithium-ion diffusion, effectively improving the rate performance of this composite material.

[0039] Figure 2The figures show the initial charge-discharge curves of the cathode materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 at 0.1C. The figures demonstrate that the 0.5Li composite lithium-ion battery cathode material exhibits a "mother-daughter sphere" morphology. 1.2 Ni 0.2 Mn 0.6 O2·0.5Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 has a high initial discharge specific capacity.

[0040] Figure 3 The figure shows the cycling performance of the cathode materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 after 100 cycles at 1C. The figure shows that the 0.5Li composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology prepared in Example 1... 1.2 Ni 0.2 Mn 0.6 O2·0.5Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 The O2 cycle performs best.

[0041] Figure 4 The figure shows the rate performance graphs of the cathode materials prepared in Example 1, Comparative Example 1, and Comparative Example 2. As can be seen from the figure, the composite lithium-ion battery cathode material 0.5Li prepared in Example 1, with a "mother-daughter sphere" morphology, exhibits this characteristic. 1.2 Ni 0.2 Mn 0.6 O2·0.5Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 still exhibits good electrochemical performance at high rates.

[0042] Table 1 shows the tap density, initial coulombic efficiency at 0.1C, and voltage decay after 100 cycles at 1C for the cathode materials prepared in Example 1, Comparative Example 1, and Comparative Example 2. As can be seen from the table, the 0.5Li composite lithium-ion battery cathode material with a "mother-daughter sphere" morphology described in this invention... 1.2 Ni 0.2 Mn 0.6 O2·0.5Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 has a high tap density and excellent electrochemical performance, and has great market application prospects.

Claims

1. A composite lithium-ion battery cathode material with a mother-daughter spherical morphology, characterized in that, The positive electrode material includes daughter spheres and mother spheres. The daughter spheres fill the interior of the mother sphere, and the inner daughter spheres are tightly bonded to the outer mother sphere, with gaps between the multiple daughter spheres. The daughter spheres are solid small particles, and the mother spheres are hollow large particles. The particle size of the daughter spheres inside the positive electrode material is adjustable, and the outer mother sphere has a complete morphology. The daughter spheres are one or more lithium-ion battery positive electrode materials, and the mother sphere is one lithium-ion battery positive electrode material. The daughter spheres and the mother spheres are different lithium-ion battery positive electrode materials. The cathode materials used in the daughter and mother spheres for lithium-ion batteries include lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, binary materials for lithium-ion batteries, ternary materials for lithium-ion batteries, lithium-rich manganese-based cathode materials for lithium-ion batteries, and lithium iron phosphate.

2. The composite lithium-ion battery cathode material with a mother-daughter spherical morphology as described in claim 1, characterized in that, The particle size D50 of the daughter ball is ≤10μm, and the particle size D50 of the mother ball is ≥15μm.

3. The composite lithium-ion battery cathode material with a mother-daughter spherical morphology as described in claim 1, characterized in that, The molar percentage of the daughter sphere in the composite lithium-ion battery cathode material with the morphology of the mother and daughter spheres is 20%-80%.

4. A method for preparing a composite lithium-ion battery cathode material with a mother-daughter spherical morphology as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Preparation of sub-spheres: Weigh various raw materials in stoichiometric ratio according to the chemical formula of the sub-spheres of the composite lithium-ion battery cathode material with the morphology of the mother and daughter spheres, mix the various raw materials in a certain way under the action of appropriate additives, and sinter to obtain sub-spheres; The additives used in the preparation of the sub-spheres are one or more of the following: ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, citric acid, PEG, PAM, PAN, CMC, hexadecyltrimethylammonium bromide, sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, and polyvinylpyrrolidone. (2) Preparation of mother-daughter spheres: Weigh the raw materials in stoichiometric ratio according to the chemical formula of the mother sphere of the composite lithium-ion battery cathode material with the morphology of the mother-daughter spheres, wet mix the various raw materials, add a certain amount of dispersant, and after complete dispersion, perform wet grinding. After grinding, add the daughter spheres prepared in the first step to the slurry and mix evenly, and then perform centrifugal spray drying and sintering to obtain the composite lithium-ion battery cathode material with the morphology of the mother-daughter spheres. The dispersant used in the wet mixing process is one or more of PEG, PAM, PAN, CMC, cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, and polyvinylpyrrolidone.

Images