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US-12626916-B2 - Aluminum-coated precursor, preparation method therefor, and use thereof

US12626916B2US 12626916 B2US12626916 B2US 12626916B2US-12626916-B2

Abstract

Disclosed are an aluminum-coated precursor and a preparation method therefor. The aluminum coated precursor has a chemical formula of xMCO 3 (1-x)·Al(OH) 3 , wherein M is at least one of nickel, cobalt and manganese, and x is 0.995-0.999. The aluminum-coated precursor has the advantages of a controllable particle size and uniform particle size distribution, a high degree of sphericity, a smooth particle surface, a high tap density, not easily breaking, and an excellent electrochemical performance and energy density.

Inventors

  • Yongjie Zhang
  • Jiangtao Wan
  • Haipeng Ren
  • Ning Zhang
  • Jinxin Zhu

Assignees

  • SVOLT ENERGY TECHNOLOGY COMPANY LIMITED

Dates

Publication Date
20260512
Application Date
20201029
Priority Date
20191227

Claims (12)

  1. 1 . A method for preparing an aluminum-coated precursor, having a chemical formula of xMCO 3 (1-x)·Al(OH) 3 , wherein M is at least one of nickel, cobalt and manganese, and x is 0.995 to 0.999, comprising: (1) continuously introducing carbon dioxide in the presence of a conductive agent, mixing a metal salt with a precipitant for a precipitation reaction, and then sealing same and leaving to stand, so as to obtain pre-prepared particles; (2) mixing the pre-prepared particles with water to obtain a slurry, and with stirring, continuously introducing the metal salt, the precipitant and the carbon dioxide for a coprecipitation reaction, so as to obtain a reacted liquid; (3) mixing the reacted liquid with an aluminum salt for a reaction, and aging and stirring same, so as to obtain an aged material; and (4) successively performing iron removal, solid-liquid separation, washing, and drying on the aged material, so as to obtain an aluminum-coated precursor.
  2. 2 . The method according to claim 1 , wherein, in step (1), the metal salt comprises at least one of a soluble nickel salt, a soluble manganese salt and a soluble cobalt salt, and the metal salt is in a concentration of 899 g/L to 400 g/L.
  3. 3 . The method according to claim 2 , wherein, in step (1), the soluble nickel salt is at least one selected from the group consisting of nickel chloride, nickel nitrate, and nickel sulfate, the soluble cobalt salt is at least one selected from the group consisting of cobalt chloride, cobalt nitrate, and cobalt sulfate, and the soluble manganese salt is at least one selected from the group consisting of manganese chloride, manganese nitrate, and manganese sulfate.
  4. 4 . The method according to claim 1 , wherein, in step (1), the carbon dioxide is at a flow rate of 0.1 L/min to 0.5 L/min.
  5. 5 . The method according to claim 1 , wherein, in step (1), the metal salt and the precipitant are in a molar ratio of 1:(2 to 3.5).
  6. 6 . The method according to claim 1 , wherein, in step (1), the conductive agent is used in an amount of 10 g to 50 g, based on a total of 1 L of the metal salt and the precipitant.
  7. 7 . The method according to claim 1 , wherein, in step (1), the precipitant is at least one selected from the group consisting of sodium carbonate, ammonium bicarbonate, sodium hydroxide, and sodium bicarbonate: optionally, the sodium carbonate is in a concentration of 50 g/L to 200 g/L; optionally, the ammonium bicarbonate is in a concentration of 50 g/L to 200 g/L; optionally, the sodium hydroxide is in a concentration of 50 g/L to 200 g/L; and optionally, the sodium bicarbonate is in a concentration of 50 g/L to 200 g/L.
  8. 8 . The method according to claim 1 , wherein, in step (1), the conductive agent is at least one of glucose and fructose; wherein, in step (1), the pre-prepared particles have a particle size of 1 μm to 2 μm.
  9. 9 . The method according to claim 1 , wherein, in step (2), the slurry has a solid content of 50 g/L to 100 g/L.
  10. 10 . The method according to claim 1 , wherein, in step (2), the metal salt is continuously introduced at a flow rate of 100 mL/h to 500 mL/h, the precipitant is continuously introduced at a flow rate of 100 mL to 500 mL/h, and the carbon dioxide is continuously introduced at a flow rate of 0.25 L/min to 0.6 L/min, and the reacted liquid has a solid content of 30 g/L to 500 g/L.
  11. 11 . The method according to claim 1 , wherein, in step (2), with stirring, a complexing agent is continuously introduced, the complexing agent is ammonia water or ammonium bicarbonate, and the complexing agent is ammonia water or ammonium bicarbonate.
  12. 12 . The method according to claim 1 , wherein, in step (3), the reacted liquid and the aluminum salt are in a volume ratio of (10 to 20):1, the aluminum salt is at least one of aluminum chloride and aluminum sulfate, and the aluminum salt is in a concentration of 10 g/L to 50 g/L.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This Application is a national stage filing under 35 U.S.C. § 371 of International Patent Application Serial No. PCT/CN2020/124789, filed Oct. 29, 2020, which claims priority to Chinese application number 201911377185.7 filed on Dec. 27, 2019. The entire contents of these applications are incorporated herein by reference in their entirety. TECHNICAL FIELD The present disclosure relates to the field of lithium batteries, for example, to an aluminum-coated precursor, a preparation method therefor, and use thereof. BACKGROUND Lithium-ion batteries play an important role in daily life. The development of the new energy automobile industry puts forward new requirements for lithium-ion batteries, and the improvement of the energy density of lithium-ion batteries is in urgent need. Lithium-rich manganese-based cathode materials have advantages of high specific capacity of 250 mAh/g to 350 mAh/g, low price, and environmental friendliness and thus have a high research value. The existing preparation of lithium-rich manganese-based cathode materials is generally divided into two steps, the first step is the preparation of a lithium-rich precursor, and the second step is the sintering of the precursor. The physical characteristics of lithium-rich manganese-based materials, such as morphology, particle size distribution and tap density, depend on the precursor to a great extent. However, the existing lithium-rich manganese-based precursors in the market have various defects, such as small particle size, low tap density (≤1.5 g/cm3) and poor degree of sphericity. Therefore, the existing lithium-rich manganese-based precursors need to be improved. SUMMARY The present disclosure provides an aluminum-coated precursor, a preparation method therefor, and use thereof. The present disclosure provides an aluminum-coated precursor in an embodiment. The precursor has a chemical formula of xMCO3(1-x)·Al(OH)3, where M is at least one of nickel, cobalt and manganese, and x is 0.995 to 0.999, for example, 0.995, 0.996, 0.997, 0.998, 0.999, etc. In an embodiment provided by the present disclosure, the aluminum-coated precursor has the advantages of controllable particle size, uniform particle size distribution, high degree of sphericity, smooth particle surface, high tap density, not easily breaking, excellent electrochemical performance, and excellent energy density, and meanwhile, the cathode material prepared by using the precursor has a high specific capacity, excellent cycle performance, and excellent electrochemical discharge performance. In an embodiment, the precursor has a particle size of 6 μm to 15 μm, for example, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm, etc., and the precursor has a tap density of not lower than 1.8 g/cm3, for example, 1.81 g/cm3, 1.82 g/cm3, 1.83 g/cm3, 1.84 g/cm3, 1.85 g/cm3, 1.86 g/cm3, 1.87 g/cm3, 1.88 g/cm3, 1.89 g/cm3 or 1.9 g/cm3, etc. The present disclosure provides a method for preparing the precursor in an embodiment. The method includes: (1) continuously introducing carbon dioxide in the presence of a conductive agent, mixing a metal salt with a precipitant for a precipitation reaction, and then sealing the same and leaving to stand, so as to obtain pre-prepared particles;(2) mixing the pre-prepared particles with water to obtain a slurry, and with stirring, continuously introducing the metal salt, the precipitant and carbon dioxide for a coprecipitation reaction, so as to obtain a reacted liquid;(3) mixing the reacted liquid with an aluminum salt for a reaction, and aging and stirring the same, so as to obtain an aged material; and(4) successively performing iron removal, solid-liquid separation, washing, and drying on the aged material, so as to obtain an aluminum-coated precursor. In an embodiment provided by the present disclosure, first, carbon dioxide is continuously introduced in the presence of a conductive agent, and then a metal salt and a precipitant are added. In the above step, the continuous introduction of carbon dioxide can adjust the pH of the system, maintain the inert environment of the system, prevent metal elements from being oxidized during coprecipitation and improve the degree of sphericity of the precursor, and the conductive agent can improve the rate capability of the material. Then, the metal salt, the precipitant, carbon dioxide and a complexing agent are continuously introduced into the slurry obtained by mixing the pre-prepared particles with water. In the above step, the complexing agent can reduce the reaction speed of the system and inhibit the formation of new particles in the system, the metal salt and the precipitant are subjected to the coprecipitation reaction in this process with the pre-prepared particles of small particle size as seed crystals, and meanwhile, the precipitant and carbon dioxide are continuously introduced in this process to continue to maintain the pH stability of the sys