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CN-115986093-B - Positive electrode active material, secondary battery and electric device

CN115986093BCN 115986093 BCN115986093 BCN 115986093BCN-115986093-B

Abstract

The application discloses an anode active material, a secondary battery and electric equipment. The positive electrode active material comprises a core material and a shell layer distributed on the surface of the core material, wherein the shell layer comprises at least one of aluminum-containing oxide and boron-containing oxide, and fluoride. The aluminum-containing oxide and/or boron-containing oxide can react with the residual lithium compound on the surface of the core material, so that the residual lithium compound is prevented from reacting with the adhesive in the positive electrode slurry in the homogenizing process, and the stability of the structure of the positive electrode active material is favorably maintained. The fluoride can make the shell resist the attack of hydrofluoric acid in the fluorine-containing electrolyte, not only can maintain the stability of the structure of the positive electrode active material, but also can improve the trafficability of electrons and ions, and can improve the performances of gram capacity, high-temperature circulation capacity and the like of the secondary battery.

Inventors

  • LIU YICHENG
  • CHEN WEI
  • HU YI
  • CHU CHUNBO
  • ZHANG YAO

Assignees

  • 欣旺达电动汽车电池有限公司

Dates

Publication Date
20260508
Application Date
20230220

Claims (12)

  1. 1. A positive electrode active material is characterized by comprising a core material and a shell layer distributed on the surface of the core material, wherein the shell layer comprises aluminum-containing oxide, boron-containing oxide and fluoride, the fluoride comprises at least one of aluminum-containing fluoride and boron-containing fluoride, the aluminum-containing oxide and the boron-containing oxide comprise oxide type fast ion conductors, and the fluoride comprises fluoride type fast ion conductors; The positive electrode active material satisfies: I=BET×TD× (Dv 99-Dv 50), 2≤I≤20, BET is the specific surface area of the positive electrode active material, and the unit is m 2 /g, and BET is more than or equal to 0.2 and less than or equal to 5.5; TD is the tap density of the positive electrode active material under 60MPa, and the unit is g/cm 3 , and TD is more than or equal to 1.2 and less than or equal to 3.0; dv99 is the particle size corresponding to the volume cumulative distribution percentage of the positive electrode active material reaching 99%, and the unit is mu m; Dv50 is the particle size corresponding to the volume cumulative distribution percentage of the positive electrode active material reaching 50%, and the unit is mu m, and Dv50 is more than or equal to 1.5 and less than or equal to 7.5.
  2. 2. The positive electrode active material according to claim 1, wherein the aluminum-containing oxide includes at least one of LiAlO 2 、LiAl 5 O 8 、Li 2 Al 4 O 7 、Li 3 AlO 3 and Li 5 AlO 4 .
  3. 3. The positive electrode active material according to claim 1, wherein the aluminum-containing oxide further comprises Al 2 O 3 .
  4. 4. The positive electrode active material according to claim 1, wherein the boron-containing oxide includes at least one of LiBO 2 、LiB 5 O 8 、Li 2 B 4 O 7 、Li 3 BO 3 and Li 5 BO 4 .
  5. 5. The positive electrode active material according to claim 1, wherein the boron-containing oxide further comprises B 2 O 3 .
  6. 6. The positive electrode active material according to claim 1, wherein the aluminum-containing fluoride includes at least one of LiAlF 4 、LiAl 5 F 16 、LiAl 2 F 7 、Li 3 AlF 6 and Li 5 AlF 8 , and the boron-containing fluoride includes at least one of LiBF 4 、LiB 5 F 16 、LiB 2 F 7 、Li 3 BF 6 and Li 5 BF 8 .
  7. 7. The positive electrode active material according to claim 1, wherein the core material comprises Li x Ni a Co b Mn c Me d O 2 , wherein 0.8+.x+.1.1, 0.5< a <1, 0+.b <0.3,0< c <0.4,0< d <0.2, a+b+c+d=1, me is selected from one or more of V, al, zr, sr, ti, B, mg, sn and W.
  8. 8. The positive electrode active material according to claim 1, wherein the content of the fluoride is 0.02% to 2% based on the mass of the positive electrode active material.
  9. 9. The positive electrode active material according to claim 1, wherein the thickness of the shell layer is 0.1nm to 20nm.
  10. 10. The positive electrode active material according to claim 1, wherein Dv99 satisfies 3≤Dv99≤15.5.
  11. 11. A secondary battery comprising a positive electrode sheet containing the positive electrode active material according to any one of claims 1 to 10.
  12. 12. An electric device comprising the secondary battery according to claim 11 as a power supply source of the electric device.

Description

Positive electrode active material, secondary battery and electric device Technical Field The application belongs to the technical field of batteries, and particularly relates to an anode active material, a secondary battery and electric equipment. Background Secondary batteries, particularly lithium ion batteries, have been widely used in the field of electric vehicles because of their advantages such as high energy density and long life cycle. Common positive electrode active materials for lithium ion batteries include layered high nickel ternary materials. Because residual alkali (such as LiOH, li 2CO3 and the like) exists on the surface of the layered high-nickel ternary material, the residual alkali is easy to react with the adhesive in the positive electrode plate to cause the adhesive to lose bonding performance, and the transmission of electrons and ions in the positive electrode plate is affected. In addition, the layered high-nickel ternary material is directly contacted with the electrolyte, so that the layered high-nickel ternary material is easily corroded by fluorine-containing substances in the electrolyte, and the capacity of the secondary battery is attenuated and the cycle performance of the secondary battery is reduced. Disclosure of Invention The embodiment of the application provides an anode active material, a secondary battery and electric equipment. The positive electrode active material can reduce residual alkali on the surface, effectively resist corrosion of hydrofluoric acid in electrolyte and solve the technical problems of capacity attenuation and cycle performance reduction of a battery. According to the technical scheme, the application provides a positive electrode active material. The positive electrode active material comprises a core material and a shell layer distributed on the surface of the core material. The shell layer includes at least one of an aluminum-containing oxide and a boron-containing oxide, and a fluoride. Optionally, in an embodiment of the application, the aluminum-containing oxide includes at least one of Al2O3、LiAlO2、LiAl5O8、Li2Al4O7、Li3AlO3 and Li 5AlO4. Optionally, in an embodiment of the application, the boron-containing oxide comprises at least one of B2O3、LiBO2、LiB5O8、Li2B4O7、Li3BO3 and Li 5BO4. Alternatively, in an embodiment of the present application, the fluoride comprises at least one of an aluminum-containing fluoride comprising at least one of AlF 3、LiAlF4、LiAl5F16、LiAl2F7、Li3AlF6 and Li 5AlF8 and a boron-containing fluoride comprising at least one of BF 3、LiBF4、LiB5F16、LiB2F7、Li3BF6 and Li 5BF8. Optionally, in an embodiment of the present application, the core material comprises Li xNiaCobMncMedO2, wherein 0.8+.x+.1.1, 0.5< a <1, 0+.b <0.3,0< c <0.4,0< d <0.2, a+b+c+d=1, me is selected from one or more of V, al, zr, sr, ti, B, mg, sn and W. Alternatively, in the embodiment of the present application, the content of the fluoride is 0.02% to 2% based on the mass of the positive electrode active material. Alternatively, in an embodiment of the present application, the thickness of the shell layer is 0.1nm to 20nm. Alternatively, in an embodiment of the present application, the positive electrode active material satisfies the following characteristics: I=BET×TD× (Dv 99-Dv 50), 2≤I≤20, BET is the specific surface area of the positive electrode active material, and the unit is m 2/g, and BET is more than or equal to 0.2 and less than or equal to 5.5; TD is the tap density of the positive electrode active material under 60MPa, and the unit is g/cm 3, and TD is more than or equal to 1.2 and less than or equal to 3.0; Dv99 is the particle size corresponding to the volume cumulative distribution percentage of the positive electrode active material reaching 99%, the unit is mu m, dv99 is not less than 3 and not more than 15.5, and Dv99 is not less than 5.9 and not more than 10.4. Dv50 is the particle size corresponding to the volume cumulative distribution percentage of the positive electrode active material reaching 50%, and the unit is mu m, and Dv50 is more than or equal to 1.5 and less than or equal to 7.5. In another aspect of the present application, a secondary battery is provided. The secondary battery includes a positive electrode sheet containing the positive electrode active material of any of the above embodiments. In yet another aspect, the application provides a powered device. The electric equipment comprises the secondary battery in any embodiment, and the secondary battery is used as a power supply of the electric equipment. Compared with the prior art, the technical scheme of the embodiment of the application has the beneficial effects that the shell layer is distributed on the surface of the core material of the positive electrode active material, and the shell layer comprises at least one of aluminum-containing oxide and boron-containing oxide and fluoride. The aluminum-containing oxide and/or boron-containing oxide can react with