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CN-122003740-A - Positive electrode active material, preparation method thereof, positive electrode plate, battery and electric equipment

CN122003740ACN 122003740 ACN122003740 ACN 122003740ACN-122003740-A

Abstract

The positive electrode active material comprises Na 4‑a A b Fe 3‑c B d (PO 4 ) 2‑e D f (P 2 O 7 , wherein A comprises at least one of Li or K, B comprises metal elements, D comprises at least one of halogen anions, silicate ions, sulfate ions or borate ions, -0.12, B-0, c-0.3, D-0, f-0, 0< e-0.1.

Inventors

  • ZHAO YUZHEN
  • WEN YAN
  • HUANG QISEN
  • GUAN YINGJIE
  • QIN MENG
  • LIN DE
  • LIU YONGYOU

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20240311
Priority Date
20231009

Claims (20)

  1. A positive electrode active material includes Na 4-a A b Fe 3-c B d (PO 4 ) 2-e D f (P 2 O 7 Wherein A comprises at least one of Li or K, B comprises a metal element, D comprises at least one of halogen anions, silicate ions, sulfate ions or borate ions, -0.12≤a≤0.12, b≤0≤c≤0.3, d≤0, f≤0, 0< e≤0.1.
  2. The positive electrode active material according to claim 1, wherein 1≤f/e≤3.
  3. The positive electrode active material according to claim 1 or 2, wherein the values of f and e satisfy at least one of 0<f≤0.3 and 0< e≤0.05.
  4. The positive electrode active material according to any one of claims 1 to 3, wherein 0<f≤0.15.
  5. The positive electrode active material according to any one of claims 1 to 4, wherein 3.88≤4-a+b≤4.12.
  6. The positive electrode active material according to any one of claims 1 to 5, wherein 2.7≤3-c+d≤3.
  7. The positive electrode active material according to any one of claims 1 to 6, wherein at least one of the following conditions is satisfied: b comprises at least one of Al, mg, ca, ni, co, mn, cu, zn, cr, V, ti, sr, Y, mo, nb or W; D includes at least one of the halogen anion, the silicate ion, or the borate ion.
  8. The positive electrode active material according to any one of claims 1 to 7, wherein the halogen anion comprises F - or Cl - .
  9. The positive electrode active material according to any one of claims 1 to 8, wherein D includes any two of the halogen anion, the silicate ion, the sulfate ion, or the borate ion, 1≤f/e≤3.
  10. The positive electrode active material according to any one of claims 1 to 9, wherein the values of b, c and d satisfy at least one of 0≤b≤0.1, 0.05≤c≤0.2, 0≤d≤0.3, and c≤d.
  11. The positive electrode active material according to any one of claims 1 to 10, wherein the positive electrode active material further comprises carbon.
  12. The positive electrode active material according to claim 11, wherein the mass ratio of the carbon is 0.5 to 4% based on the total mass of the positive electrode active material.
  13. The positive electrode active material according to claim 11 or 12, wherein the mass ratio of carbon is 1 to 3% based on the total mass of the positive electrode active material.
  14. The positive electrode active material according to any one of claims 1 to 13, wherein at least one of the following conditions is satisfied: The positive electrode active material has a volume average particle diameter D v 50 0 of 0.7-7 [ mu ] m; The BET specific surface area of the positive electrode active material was 4m 2 /g-12m 2 /g.
  15. The positive electrode active material according to any one of claims 1 to 14, wherein at least one of the following conditions is satisfied: The positive electrode active material has a volume average particle diameter D v 50 0 of 1.2 μm to 4 μm; The BET specific surface area of the positive electrode active material was 5.5m 2 /g-10m 2 /g.
  16. A method of preparing the positive electrode active material according to any one of claims 1 to 15, comprising: Mixing a sodium source, an iron source, a phosphorus source and a D source to obtain a precursor material; sintering the precursor material to obtain the positive electrode active material.
  17. The method of claim 16, further comprising adding an A source and/or a B source to the precursor material.
  18. The method of claim 16 or 17, wherein the method further comprises adding a first carbon source to the precursor material.
  19. The method of any of claims 16-18, wherein the method further comprises mixing and sintering the positive electrode active material with a second carbon source to form a carbon coating on the surface of the positive electrode active material.
  20. The method of any of claims 16-19, wherein the sintering comprises a first sintering and a second sintering, the first sintering and the second sintering satisfying at least one of the following conditions: The temperature of the first sintering is 200-400 ℃, and the heat preservation time is 3-5 h; The temperature of the second sintering is 450-650 ℃, and the heat preservation time is 8-15 h.

Description

Positive electrode active material, preparation method thereof, positive electrode plate, battery and electric equipment Technical Field The application relates to the field of batteries, in particular to an anode active material, a preparation method, an anode plate, a battery and electric equipment. Background The battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles, and the like, as well as a plurality of fields such as military equipment, aerospace, and the like. The Na 4Fe3(PO4)2P2O7 positive electrode active material in the sodium ion battery has sufficient resources, is environment-friendly and is easy for large-scale production, so the Na 4Fe3(PO4)2P2O7 positive electrode active material is one of the positive electrode active materials of the hot sodium ion battery. However, the intrinsic conductivity of the material is poor, so that the gram capacity of the material is influenced, and the energy density and the multiplying power performance of the battery are reduced. Disclosure of Invention In view of the technical problems existing in the background art, the application provides the positive electrode active material, which can improve gram capacity of the positive electrode active material and improve energy density and rate capability of a battery. A first aspect of the present application provides a positive electrode active material, comprising Na 4-aAbFe3-cBd(PO4)2-eDf(P2O7), wherein A comprises at least one of Li or K, B comprises a metal element, D comprises at least one of a halogen anion, a silicate ion, a sulfate ion or a borate ion, -0.12≤a≤0.12, b≤0, 0≤c≤0.3, d≤0, f≤0, 0< e≤0.1. When the positive electrode active material is only doped with the anions D, the anions can replace part of phosphate ions, so that the local chemical bonds and electron distribution of the positive electrode active material are regulated, the intrinsic conductivity of the positive electrode active material is improved, the gram capacity of the positive electrode active material is improved, and the energy density and the multiplying power performance of the battery are improved. When at least one of anions D and cations A, B is doped in the positive electrode active material, the anions and cations cooperate to improve the purity of the positive electrode active material, improve the structural stability of the positive electrode active material, improve the ionic conductivity and the electronic conductivity of the positive electrode active material, improve the phase purity, improve the gram capacity of the positive electrode active material and improve the energy density and the multiplying power performance of the battery. According to some embodiments of the application, 1≤f/e≤3. Thus, the intrinsic conductivity of the positive electrode active material is improved, the gram capacity of the material is improved, and the energy density and the multiplying power performance of the battery are improved. According to some embodiments of the application 0<f≤0.3. Thus, the intrinsic conductivity of the positive electrode active material is improved, and the gram capacity of the positive electrode active material is improved. According to some embodiments of the application 0<f≤0.15. Thus, the intrinsic conductivity of the positive electrode active material is improved, and the gram capacity of the positive electrode active material is improved. According to some embodiments of the application 0<e≤0.05. Thus, the intrinsic conductivity of the positive electrode active material is improved, and the gram capacity of the positive electrode active material is improved. According to some embodiments of the application, 3.88≤4-a+b≤4.12. Thereby, the stability of the positive electrode active material is improved. According to some embodiments of the application, 2.7≤3-c+d≤3. The phase purity of the positive electrode active material can be improved, thereby improving the gram capacity of the material and improving the energy density of the battery. According to some embodiments of the application, B comprises at least one of Al, mg, ca, ni, co, mn, cu, zn, cr, V, ti, sr, Y, mo, nb or W. According to some embodiments of the application, D comprises at least one of the halogen anion, the silicate ion, or the borate ion. According to some embodiments of the application, the halogen anion comprises F - or Cl -. Thus, by doping the anions and cations of the above-mentioned types into the positive electrode active material, the ion conductivity and electron conductivity of the positive electrode active material are improved, the purity of the positive electrode active material is improved, the gram capacity of the material is improved, and the energy density and rate capability of the battery are improved. According to some