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CN-117303460-B - Carbonate precursor, high-nickel monocrystal positive electrode material and preparation method of high-nickel monocrystal positive electrode material

CN117303460BCN 117303460 BCN117303460 BCN 117303460BCN-117303460-B

Abstract

The invention discloses a carbonate precursor, a high-nickel monocrystal positive electrode material and a preparation method thereof, and relates to the technical field of positive electrode materials of lithium ion batteries. The preparation method of the high-nickel monocrystal anode material comprises the following steps of sintering a carbonate precursor, mixing the carbonate precursor with lithium hydroxide and strontium carbonate, sintering the mixed material in pure oxygen atmosphere, naturally cooling the sintered material, performing jet milling to obtain an intermediate product, uniformly mixing the intermediate product with cobalt hydroxide, titanium dioxide and lithium hydroxide, sintering the mixture in pure oxygen atmosphere, naturally cooling the sintered material, and naturally cooling the sintered material after sintering. The preparation method has the beneficial effects that the precursor with high specific surface area is prepared by the urea pyrolysis method, and then the precursor with high porosity is obtained after presintering, so that the high-temperature sintering temperature of the high-nickel monocrystal ternary material can be obviously reduced, the disproportionation reaction of trivalent nickel can be effectively reduced, and the prepared high-nickel monocrystal positive electrode material has the characteristics of large primary particles, smooth surface and high gram capacity.

Inventors

  • WANG ZHENG
  • WANG XINPENG
  • ZHANG LEI
  • LI RUNLONG
  • SONG XIAOTING
  • HE YAN

Assignees

  • 安徽天力锂能有限公司

Dates

Publication Date
20260508
Application Date
20230926

Claims (10)

  1. 1. A method for preparing a carbonate precursor, comprising the steps of: (1) Adding nickel nitrate, cobalt nitrate and manganese nitrate with certain weight into a certain volume of water, preparing nitrate solution with certain concentration, and then adding a certain amount of citric acid, wherein the molar ratio of the citric acid to nickel cobalt manganese element is (1-10): 100, and the molar ratio of nickel, cobalt and manganese is (63-85): 5-7): 10-32; (2) Adding a certain weight of urea into a certain volume of water to prepare a urea solution with a certain concentration, wherein the concentration of the urea solution is 20-50mg/mL; (3) Heating the urea solution in the step (2) to a certain temperature, and then adding the solution in the step (1) into the heated urea solution to react to obtain a carbonate precursor, wherein the certain temperature is 70-100 ℃.
  2. 2. The method for preparing a carbonate precursor according to claim 1, wherein the molar ratio of citric acid to nickel cobalt manganese element in the step (1) is 5:100, and the molar ratio of nickel, cobalt and manganese in the step (1) is 63:7:30.
  3. 3. The method for preparing a carbonate precursor according to claim 1, wherein the concentration of urea solution in the step (2) is 30mg/mL.
  4. 4. The method for preparing a carbonate precursor according to claim 1, wherein the certain temperature in the step (3) is 75 ℃.
  5. 5. A carbonate precursor produced by the production process of any one of claims 1 to 4.
  6. 6. The carbonate precursor of claim 5, wherein the chemical formula is Ni x Co y Mn z CO 3 , wherein 0.60≤x≤ 0.88,0.03≤y≤0.15, 0.06≤z≤0.35, x+y+z=1.00, the particle size D50 of the carbonate precursor is 2-6 μm, and the specific surface area of the carbonate precursor is 87, 89, 92, 95, 85, 83, 86 or 96m 2 /g.
  7. 7. The preparation method of the high-nickel monocrystal positive electrode material is characterized by comprising the following steps of: S1, sintering the carbonate precursor of claim 5 to obtain nickel cobalt manganese oxide; s2, mixing the nickel cobalt manganese oxide obtained in the step S1 with lithium hydroxide and strontium carbonate according to a certain proportion, wherein the molar ratio of the lithium element to the nickel cobalt manganese element after mixing is (1.04-1.10): 1, and the molar ratio of the strontium to the nickel cobalt manganese element is (50-200); s3, sintering the mixed materials in the step S2 in pure oxygen atmosphere, and naturally cooling after sintering; s4, carrying out jet milling on the material cooled in the step S3 to obtain an intermediate product; S5, uniformly mixing the intermediate product obtained in the step S4 with cobalt hydroxide, titanium dioxide and lithium hydroxide according to a certain proportion, wherein the cobalt hydroxide accounts for 1% of the mass of the intermediate product; and S6, sintering the uniformly mixed materials in the step S5 in pure oxygen atmosphere, naturally cooling after sintering, and naturally cooling after sintering to obtain the high-nickel monocrystal anode material.
  8. 8. The method for producing a high nickel single crystal positive electrode material according to claim 7, wherein the sintering condition in the step S1 is that the sintering temperature is 750 ℃ and the sintering time is 5 to 7 hours at an oxygen concentration of > 80%.
  9. 9. The method for producing a high nickel single crystal positive electrode material according to claim 7, wherein the sintering temperature in the step S3 is 890 to 945 ℃, and the sintering temperature in the step S6 is 750 ℃.
  10. 10. The high nickel single crystal positive electrode material produced by the production method according to any one of claims 7 to 9.

Description

Carbonate precursor, high-nickel monocrystal positive electrode material and preparation method of high-nickel monocrystal positive electrode material Technical Field The invention belongs to the technical field of lithium ion battery anode materials, and particularly discloses a carbonate precursor, a high-nickel monocrystal anode material and a preparation method thereof. Background In recent years, with the rapid development of the new energy automobile industry, the demand of lithium ion batteries is rapidly increased, the demand of people for the endurance mileage of the new energy automobile is higher and higher, the demand of high-energy-density and high-safety lithium ion batteries is rapidly increased, due to the low energy density of lithium iron phosphate and the poor safety performance of primary particles, the high-nickel polycrystalline material cannot meet the two indexes of high energy density and high safety at the same time, and the high-nickel monocrystal positive electrode material has high capacity due to the high gram of nickel content, and simultaneously has large primary particles and good heat stability, and can meet the two indexes of high energy density and high safety at the same time. The high nickel monocrystal anode material has the characteristics of high capacity and high safety, and also has certain defects that the primary particles are large due to higher nickel content, the required sintering temperature is too high, trivalent nickel has poor stability at high temperature, and is easy to disproportionate into divalent nickel and tetravalent nickel, so that the gram capacity of the material is reduced. The preparation process of the high-nickel monocrystal anode material mainly comprises a secondary sintering process, and specifically comprises the steps of uniformly mixing a precursor, lithium hydroxide and an additive, performing primary high-temperature sintering in a kiln, crushing, performing surface coating, and performing secondary sintering, wherein the precursor is basically hydroxide prepared by coprecipitation, has the characteristic of high tap density, and has the defects of poor reactivity and difficult growth in the process of mixing and sintering with lithium salt. The Chinese patent application publication No. CN115028210A discloses a preparation method of a monocrystal high-nickel cathode material, which belongs to the field of lithium ion batteries, and comprises the steps of firstly preparing a monocrystal doped nickel hydroxide precursor with larger primary particles by an ammonia complexation-boiling precipitation method, mixing the precursor with a lithium source, and calcining under an oxygen atmosphere to obtain the monocrystal cathode material with the primary particles of 1-5 mu m, wherein the preparation method can break through the harsh conditions such as high temperature, high lithium excess ratio and the like and the complicated procedures such as water washing and the like involved in the preparation of the traditional monocrystal cathode material, and has the advantages of short flow, energy conservation, consumption reduction, wide applicability and the like. However, this patent does not address lowering the sintering temperature, increasing the particles, surface smoothness, gram volume, etc. of the material. Disclosure of Invention The invention aims to solve the technical problems of how to prepare needle-shaped carbonate precursors with high specific surface area, how to reduce the high-temperature sintering temperature and prepare the high-nickel monocrystal anode material with large primary particles, smooth surface and high gram capacity. The invention solves the technical problems by the following technical means: In a first aspect of the present invention, a carbonate precursor is provided, which has a chemical formula of Ni xCoyMnzCO3, wherein 0.60-0.88,0.03-y-0.15, 0.06-z-0.35, x+y+z=1.00, and the particle size D50 of the carbonate precursor is 2-6 μm. The method has the beneficial effects that the method adopts the urea pyrolysis method to prepare the carbonate precursor, utilizes the reaction of carbon dioxide generated by the urea pyrolysis and nickel cobalt manganese metal ions to prepare nickel cobalt manganese carbonate, controls the morphology and the specific surface area of the precursor by controlling the urea decomposition speed, and the prepared carbonate precursor has higher specific surface area and needle-shaped morphology. Preferably, the carbonate precursor has a nickel content mole ratio of greater than 60% and less than 88%, a cobalt content mole ratio of greater than 3% and less than 15%, and a manganese content of greater than 6% and less than 35%. The second aspect of the present invention proposes a method for preparing the carbonate precursor, comprising the steps of: (1) Adding a certain weight of nickel nitrate, cobalt nitrate and manganese nitrate into a certain volume of water, preparing a nitrate