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CN-122025613-A - Positive electrode material, preparation method thereof, positive electrode plate and battery

CN122025613ACN 122025613 ACN122025613 ACN 122025613ACN-122025613-A

Abstract

The invention relates to the technical field of batteries, in particular to a positive electrode material, a preparation method thereof, a positive electrode plate and a battery. The positive electrode material comprises a core, a first coating layer, a second coating layer and a selenium oxide, wherein the core comprises a high-nickel ternary positive electrode material, the first coating layer is coated on the surface of the core and comprises cobalt oxide, titanium oxide and aluminum oxide, the second coating layer is coated on the surface of the first coating layer and comprises selenium oxide, and the surface of the high-nickel ternary positive electrode material is treated by organic acid. According to the technical scheme, the structural stability and the interface stability of the material in a long-term circulation process are effectively improved while the residual alkali on the surface of the material is reduced, and further, the excellent circulation life and capacity retention rate are realized.

Inventors

  • ZHANG YEQIONG
  • FAN XINYUE
  • GENG HAO
  • ZHAO HUIWEN
  • ZHANG YUHAN
  • YU HONGJIANG
  • XU HAI
  • WANG YANHONG
  • CHEN JICHENG
  • CHEN YANHE
  • ZHANG LEI
  • JIANG KECHENG
  • WANG CHAOYUE
  • SONG XIAOMING

Assignees

  • 江苏正力新能电池技术股份有限公司
  • 辽宁通用航空研究院

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. A positive electrode material, characterized in that the positive electrode material comprises: the inner core comprises a high-nickel ternary positive electrode material; the first coating layer is coated on the surface of the inner core and comprises cobalt oxide, titanium oxide and aluminum oxide; And a second coating layer coated on the surface of the first coating layer, wherein the second coating layer comprises selenium oxide; wherein the surface of the high-nickel ternary positive electrode material is treated by organic acid.
  2. 2. The positive electrode material according to claim 1, wherein the mass ratio of cobalt oxide, titanium oxide, aluminum oxide in the first coating layer is (0.002-0.004): (0.001-0.0025): (0.001-0.002), and/or, The first coating layer accounts for 0.3% -0.9% of the total mass of the anode material and/or, The second coating layer accounts for 0.05% -0.15% of the total mass of the anode material.
  3. 3. The positive electrode material of claim 1, wherein the high nickel ternary positive electrode material core has a general formula LiNi a Co b Mn c O 2-α F α , wherein 0.7< a <0.85,0.10 < b <0.15,0< c <0.2, a+b+c=1, 0.003 < α <0.009.
  4. 4. The method for preparing a positive electrode material according to any one of claims 1 to 3, comprising the steps of: mixing a high-nickel ternary cathode material precursor, a lithium source and a fluorine source for first sintering to obtain a lithiation product, and mixing the lithiation product with an organic acid to obtain a modified product; mixing the modified product, the cobalt-containing coating agent, the titanium-containing coating agent and the aluminum-containing coating agent, and performing second sintering to obtain a modified product containing a first coating layer; and mixing the modified product containing the first coating layer with a selenium-containing coating agent, and performing third sintering in an inert atmosphere to obtain the anode material.
  5. 5. The method for producing a positive electrode material according to claim 4, wherein the modified product production satisfies at least one of the following characteristics (1) to (8): (1) The molar ratio of nickel ions, cobalt ions and manganese ions in the high-nickel ternary positive electrode material precursor to lithium in the lithium source is 1 (1.03-1.08); (2) The fluorine source accounts for 0.15% -0.25% of the mass of the precursor of the high-nickel ternary cathode material; (3) The mass of the lithiated product is taken as a reference, and the dosage of the organic acid is 800 ppm-1500 ppm; (4) The chemical formula of the precursor of the high-nickel ternary positive electrode material is Ni x Co y Mn z (OH) 2 , wherein x is 0.7< 0.85, y is 0.10-0.15, z is 0< 0.2, and x+y+z=1; (5) The lithium source comprises at least one of lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate and lithium citrate; (6) The fluorine source comprises at least one of ammonium fluoride, lithium fluoride and polyvinylidene fluoride; (7) The organic acid comprises citric acid; (8) The temperature rising rate of the first sintering is 3-6 ℃ per minute, the temperature is 800-900 ℃ and the time is 16-24 hours.
  6. 6. The method for producing a positive electrode material according to claim 4, wherein the production of the modified product containing the first coating layer satisfies at least one of the following characteristics (1) to (5): (1) The mass ratio of the modified product to the cobalt-containing coating agent to the titanium-containing coating agent to the aluminum-containing coating agent is 1 (0.002-0.004): (0.001-0.0025): (0.001-0.002); (2) The cobalt-containing coating agent comprises at least one of cobaltosic oxide, cobaltous oxide and cobalt hydroxide; (3) The titanium-containing coating agent comprises at least one of titanium dioxide and tetrabutyl titanate; (4) The aluminum-containing coating agent comprises at least one of aluminum oxide, aluminum hydroxide and aluminum isopropoxide; (5) The temperature rising rate of the second sintering is 2-5 ℃ per minute, the temperature is 600-730 ℃ and the time is 8-15 h.
  7. 7. The method of producing a positive electrode material according to claim 4, wherein the third sintering step satisfies at least one of the following characteristics (1) to (4): (1) The mass ratio of the modified product to the selenium-containing coating agent is 1 (0.0005-0.0015); (2) The selenium-containing coating agent comprises at least one of selenium powder and selenium dioxide; (3) The gas for providing the inert atmosphere comprises at least one of nitrogen, helium, neon, argon, krypton and xenon; (4) The temperature rising rate of the third sintering is 1.5-4 ℃ per minute, the temperature is 300-500 ℃ and the time is 4-7 hours.
  8. 8. The method for producing a positive electrode material according to claim 4 or 5, wherein the lithiated product is mixed with an organic acid by ball milling; The rotation speed of ball milling and mixing is 600 r/min-1000 r/min, and the time is 20-50 min.
  9. 9. A positive electrode sheet comprising a positive electrode material, characterized in that the positive electrode material comprises the positive electrode material according to any one of claims 1 to 3, or comprises the positive electrode material obtained by the production method according to any one of claims 4 to 8.
  10. 10. A battery comprising a positive electrode sheet, wherein the positive electrode sheet comprises the positive electrode sheet of claim 9.

Description

Positive electrode material, preparation method thereof, positive electrode plate and battery Technical Field The invention relates to the technical field of batteries, in particular to a positive electrode material, a preparation method thereof, a positive electrode plate and a battery. Background The high-nickel ternary positive electrode material can effectively improve the energy density of the lithium ion battery due to higher theoretical reversible capacity (200 mAh/g), and the high-capacity characteristic of the high-nickel ternary positive electrode material is continuously researched. However, the high-nickel ternary positive electrode material has more residual alkali on the surface and affects the processing of electrode slurry, and the high-nickel ternary positive electrode material is easy to react with electrolyte in a full-charge state to cause side reactions, so that the capacity of a battery core is reduced, and the cycle performance is deteriorated. In the related art, in order to reduce the residual alkali content on the surface of the high-nickel ternary positive electrode material, a water washing treatment is generally adopted, and then the residual alkali content on the surface of the NCM ternary positive electrode material is reduced by a sintering process at a lower temperature. However, the multiplying power and the cycle performance of the ternary material treated by the method are obviously reduced, and the use requirement of the power battery is not met. On the other hand, in order to improve the interfacial stability of the material, a single or specific component substance is used to coat the surface of the material, for example, lithium cobalt oxide, lithium manganate, lithium nickelate, lithium tungstate or lithium iron phosphate is used as a coating layer. However, such coatings may gradually fall off or become functionally impaired during long-term electrochemical cycling due to insufficient adhesion or structural failure, and it is difficult to permanently and effectively isolate electrolyte attack. Further, in the prior art, when the problems of excessive residual alkali and unstable interface are respectively solved, the problems are often considered, and the problems are difficult to be cooperatively solved. Therefore, how to effectively reduce the residual alkali on the surface and construct a uniform and firm surface structure capable of playing a protection role for a long time, thereby combining low residual alkali, high capacity and long cycle life of the material, has become a prominent technical problem in the field. Disclosure of Invention In view of the above, the present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the invention provides the positive electrode material, the preparation method thereof, the positive electrode plate and the battery, and the positive electrode material has the advantages of low residual alkali, high capacity and long cycle life. In order to solve the technical problems, the application is realized as follows: According to a first aspect of the present application, an embodiment of the present application provides a positive electrode material including: the inner core comprises a high-nickel ternary positive electrode material; the first coating layer is coated on the surface of the inner core and comprises cobalt oxide, titanium oxide and aluminum oxide; And a second coating layer coated on the surface of the first coating layer, wherein the second coating layer comprises selenium oxide; wherein the surface of the high-nickel ternary positive electrode material is treated by organic acid. In some embodiments, the mass ratio of cobalt oxide, titanium oxide and aluminum oxide in the first coating layer is (0.002-0.004): 0.001-0.0025): 0.001-0.002. In some embodiments, the first coating layer accounts for 0.3% -0.9% of the total mass of the cathode material. In some embodiments, the second coating layer accounts for 0.05% -0.15% of the total mass of the cathode material. In some embodiments, the high nickel ternary positive electrode material core has a general formula of LiNi aCobMncO2-αFα, wherein 0.7< a <0.85, 0.10+.b <0.15,0< c <0.2, a+b+c=1, and 0.003+.alpha <0.009. According to a second aspect of the present application, an embodiment of the present application provides a method for preparing a positive electrode material, including the steps of: mixing a high-nickel ternary cathode material precursor, a lithium source and a fluorine source for first sintering to obtain a lithiation product, and mixing the lithiation product with an organic acid to obtain a modified product; mixing the modified product, the cobalt-containing coating agent, the titanium-containing coating agent and the aluminum-containing coating agent, and performing second sintering to obtain a modified product containing a first coating layer; and mixing the modified product containing the firs