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CN-117730057-B - Composite ternary positive electrode material, and preparation method and application thereof

CN117730057BCN 117730057 BCN117730057 BCN 117730057BCN-117730057-B

Abstract

A preparation method of the composite ternary positive electrode material comprises the following steps of (1) mixing a mixed salt solution of calcium salt and tin salt with alkali liquor to obtain a mixed solution, (2) mixing a ternary precursor with the mixed solution, carrying out solid-liquid separation to obtain a solid material, pulping the solid material, adding hydrofluoric acid, and reacting to obtain the composite ternary precursor, (3) mixing the composite ternary precursor with a lithium source, and carrying out sintering treatment to obtain the composite ternary positive electrode material. The alkaline solution containing tin and calcium is used for alkaline washing, sulfur impurities can be removed, calcium and tin are doped in the precursor, and the precursor is modified by hydrofluoric acid to generate fluoride, so that oxide and electrolyte can be separated, side reactions in the charge and discharge processes are reduced, and the material cycle performance is obviously enhanced.

Inventors

  • WU ZHIJING
  • LI AIXIA
  • XIE YINGHAO
  • YU HAIJUN
  • LI CHANGDONG

Assignees

  • 广东邦普循环科技有限公司
  • 湖南邦普循环科技有限公司

Dates

Publication Date
20260505
Application Date
20231031

Claims (20)

  1. 1. The preparation method of the composite ternary positive electrode material comprises the following steps: (1) Mixing a mixed salt solution of calcium salt and tin salt with alkali liquor to obtain a mixed solution; (2) Mixing the ternary precursor with the mixed solution, carrying out solid-liquid separation to obtain a solid material, pulping the solid material, adding hydrofluoric acid, and reacting to obtain a composite ternary precursor; (3) And mixing the composite ternary precursor with a lithium source, and performing sintering treatment to obtain the composite ternary anode material.
  2. 2. The process according to claim 1, wherein the calcium salt of step (1) comprises calcium chloride and/or calcium nitrate.
  3. 3. The method of claim 1, wherein the tin salt of step (1) comprises tin chloride and/or tin nitrate.
  4. 4. The preparation method of claim 1, wherein the total molar concentration of the calcium salt and the tin salt in the mixed salt solution in the step (1) is 0.01-0.2 mol/L.
  5. 5. The method according to claim 4, wherein the molar ratio of the calcium element to the tin element in the mixed salt solution in the step (1) is (0.8-1.2): 1.
  6. 6. The preparation method of claim 1, wherein the molar concentration of the alkali liquor in the step (1) is 2-10 mol/L.
  7. 7. The process according to claim 1, wherein the pH of the mixed solution in the step (1) is not less than 12.
  8. 8. The method of claim 1, wherein the ternary precursor of step (2) comprises nickel cobalt manganese hydroxide.
  9. 9. The method according to claim 1, wherein the solid-to-liquid ratio of the ternary precursor and the mixed solution in the step (2) is 1 (2-5) kg/L.
  10. 10. The method of claim 1, wherein the pulping of step (2) comprises mixing a solid material with deionized water.
  11. 11. The preparation method of claim 10, wherein the solid-to-liquid ratio of the solid material and deionized water in the step (2) is 1 (2-5) kg/L.
  12. 12. The preparation method of claim 1, wherein the mass concentration of hydrofluoric acid in the step (2) is 30-40%.
  13. 13. The method according to claim 1, wherein the pH of the reaction in the step (2) is 4 to 5.
  14. 14. The preparation method of claim 1, wherein the reaction temperature in the step (2) is 100-150 ℃.
  15. 15. The preparation method of claim 1, wherein the reaction time in the step (2) is 10-30 min.
  16. 16. The method of claim 1, wherein the lithium source of step (3) comprises lithium hydroxide and/or lithium carbonate.
  17. 17. The method according to claim 1, wherein the sintering treatment in step (3) is performed at a temperature of 600 to 1000 ℃.
  18. 18. The preparation method of claim 1, wherein the sintering treatment in the step (3) is performed for 20-36 hours.
  19. 19. A composite ternary positive electrode material produced by the method of any one of claims 1-18.
  20. 20. A positive electrode sheet comprising the composite ternary positive electrode material of claim 19.

Description

Composite ternary positive electrode material, and preparation method and application thereof Technical Field The present disclosure belongs to the technical field of lithium ion batteries, and relates to a composite ternary positive electrode material, a preparation method and applications thereof. Background The lithium ion battery is considered as a new generation green high-energy battery because of the characteristics of high energy, long service life, low pollution and the like, and is widely applied to various fields such as mobile phones, digital cameras, computers, electric automobiles and the like. The positive electrode material, which is an important component of a lithium ion battery, determines the final performance of the battery. At present, the cathode materials which are studied more mainly comprise lithium cobaltate, lithium manganate, layered nickel cobalt lithium manganate and the like. Among them, layered nickel cobalt lithium manganate has concentrated the advantages of three materials of lithium cobaltate, lithium nickelate, lithium manganate, it is very rapid to develop in recent years. The most common method for synthesizing nickel cobalt lithium manganate is a coprecipitation method, namely, alkali liquor is introduced into a nickel cobalt manganese mixed salt solution to continuously generate nickel cobalt manganese hydroxide, and then a precursor is dried and then mixed with lithium salt for calcination to obtain the nickel cobalt lithium manganate. CN115215388a discloses a preparation method of ternary positive electrode material and ternary positive electrode material, which are used for improving preparation efficiency and yield of ternary positive electrode material. The method comprises the steps of mixing manganese salt and/or aluminum salt with nickel salt and cobalt salt, performing coprecipitation reaction with alkaline substances and complexing agents in a solvent to obtain coprecipitation slurry with target median particle size, washing the coprecipitation slurry to obtain ternary precursor slurry, mixing a lithium source with the ternary precursor slurry in an inert atmosphere to obtain a first mixture, drying the first mixture to obtain a second mixture, and performing high-temperature sintering treatment on the second mixture to obtain the ternary cathode material. CN105261737A discloses a preparation method of a ternary cathode material, which comprises the steps of 1, uniformly mixing and fusing salt ingredients and alkali ingredients in a solution mode to form mixed liquid, 2, precipitating the mixed liquid in the step 1 to form precursor crystal grains, controlling nucleation and crystal growth speed of coprecipitation reaction by adjusting parameters, 3, washing and press-filtering the precursor crystal grains formed in the step 2, adding a liquid phase into a cation position for doping modification, then drying, 4, adding lithium into the dried raw materials, roasting, and then carrying out surface coating modification to obtain a ternary material finished product. In the scheme, lithium ions cannot fully enter cobalt manganese nickel hydroxide, so that residual lithium appears on the surface of the cobalt nickel lithium manganate, and the cycling stability of the positive electrode material is affected. In addition, sulfate is mostly adopted as a raw material for synthesizing cobalt manganese nickel hydroxide, and part of sulfur element is contained in the cobalt manganese nickel hydroxide after coprecipitation, and is required to be removed by washing with alkaline water, so that a large amount of alkaline wastewater is generated in the step, and the environmental impact is large. If this step is omitted, the sulfur impurity content is too high, which is unfavorable for the exertion of the electrochemical performance of the positive electrode material. Disclosure of Invention The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims. The invention aims to provide a composite ternary positive electrode material, a preparation method and application thereof, and the composite ternary positive electrode material is characterized in that alkaline solution containing tin and calcium is used for alkaline washing, sulfur impurities can be removed, calcium and tin are doped in a precursor, and the precursor is modified by hydrofluoric acid to generate fluoride, so that oxide and electrolyte can be separated, side reactions in the charging and discharging processes are reduced, and the cycle performance of the material is obviously enhanced. To achieve the purpose, the present disclosure adopts the following technical scheme: in a first aspect, the present disclosure provides a method for preparing a composite ternary cathode material, the method comprising the steps of: (1) Mixing a mixed salt solution of calcium salt and tin salt with alkali liquor to obtain a mixed solution; (2) Mixi