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US-20260128303-A1 - POSITIVE ELECTRODE MATERIAL, PREPARATION METHOD THEREOF, AND LITHIUM-ION BATTERY

US20260128303A1US 20260128303 A1US20260128303 A1US 20260128303A1US-20260128303-A1

Abstract

A positive electrode material, a preparation method thereof and a lithium-ion battery are provided. A first aspect provides a positive electrode active material, where a chemical composition of the positive electrode active material is Li 1+a [Ni x Co y M1 z M2 b ]O 2±c A d , M1 is one or two of Mn or Al, M2 is one or more of Zr, Mg, Ti, Te, Al, Ca, Sr, Sb, Nb, Pb, V, Ge, Se, W, Mo, Zn, Ce, or Y; and A is one of F, Cl, or S. By controlling the Ni content in secondary particles of different particle sizes, the problem of non-uniform degradation of the secondary particles of different particle sizes during battery cycling can be avoided, thereby improving the cycling stability of lithium-ion batteries.

Inventors

  • Jian Yu
  • Xiaoxiao Huang
  • Xujun Yuan

Assignees

  • NINGBO RONBAY NEW ENERGY TECHNOLOGY CO., LTD.

Dates

Publication Date
20260507
Application Date
20251230
Priority Date
20230915

Claims (17)

  1. 1 . A positive electrode active material, wherein a chemical composition of the positive electrode active material is Li 1+a [Ni x Co y M1 z M2 b ]O 2±c A d , 0<a<0.2, 0.5≤x<1, 0<y<0.3, 0<z<0.3, 0<b<0.2, c<0.02, 0≤d≤0.05, and x+y+z+b=1; M1 is one or two of Mn or Al, M2 is one or more of Zr, Mg, Ti, Te, Al, Ca, Sr, Sb, Nb, Pb, V, Ge, Se, W, Mo, Zn, Ce, or Y; and A is one of F, Cl, or S; a X value corresponding to Ni element in the chemical composition of first particles is X1, and a X value corresponding to Ni element in the chemical composition of second particles is X2, 0.005≤(X1-X2)≤0.07; the first particles refer to particles having an average size equal to D10 of an overall particle size distribution of the positive electrode active material, and the second particles refer to particles having an average size equal to D90 of the overall particle size distribution of the positive electrode active material.
  2. 2 . The positive electrode active material according to claim 1 , wherein a Y value corresponding to Co element in the chemical composition of the first particles is Y1, and a Y value corresponding to Co element in the chemical composition of the second particles is Y2, Y2>Y1.
  3. 3 . The positive electrode active material according to claim 2 , wherein (X1-X2)> (Y2-Y1).
  4. 4 . The positive electrode active material according to claim 1 , wherein a Z value corresponding to M1 element in the chemical composition of the first particles is Z1, and a Z value corresponding to M1 element in the chemical composition of the second particles is Z2, Z2>Z1.
  5. 5 . The positive electrode active material according to claim 4 , wherein (X1-X2)> (Z2-Z1).
  6. 6 . The positive electrode active material according to claim 1 , wherein a b value corresponding to M2 element in the chemical composition of the first particles is b1, and a b value corresponding to M2 element in the chemical composition of the second particles is b2, b1=b2.
  7. 7 . The positive electrode active material according to claim 1 , wherein the first particles are composed of primary particles having a size of R1, and the second particles are composed of primary particles having a size of R2, R1<R2.
  8. 8 . The positive electrode active material according to claim 7 , wherein R1≥0.85 R2.
  9. 9 . A preparation method for the positive electrode active material according to claim 1 , comprising the following steps: mixing a nickel source, a cobalt source, and an M1 source to prepare a positive electrode active material precursor; the positive electrode active material precursor includes a first positive electrode active material precursor and a second positive electrode active material precursor, wherein the first positive electrode active material precursor has a size smaller than that of the second positive electrode active material precursor; a molar content of Ni element in a chemical composition of the first positive electrode active material precursor is W1, and a molar content of Ni element in the chemical composition of the second positive electrode active material precursor is W2, W1-W2≥0.005; mixing the positive electrode active material precursor, a lithium source, and an M2 source to form a mixed material; sintering the mixed material in an oxygen or air atmosphere to obtain the positive electrode active material.
  10. 10 . The preparation method for the positive electrode active material according to claim 9 , wherein a Y value corresponding to Co element in the chemical composition of the first particles is Y1, and a Y value corresponding to Co element in the chemical composition of the second particles is Y2, Y2>Y1.
  11. 11 . The preparation method for the positive electrode active material according to claim 10 , wherein (X1-X2)> (Y2-Y1).
  12. 12 . The preparation method for the positive electrode active material according to claim 9 , wherein a Z value corresponding to M1 element in the chemical composition of the first particles is Z1, and a Z value corresponding to M1 element in the chemical composition of the second particles is Z2, Z2>Z1.
  13. 13 . The preparation method for the positive electrode active material according to claim 12 , wherein (X1-X2)> (Z2-Z1).
  14. 14 . The preparation method for the positive electrode active material according to claim 9 , wherein a b value corresponding to M2 element in the chemical composition of the first particles is b1, and a b value corresponding to M2 element in the chemical composition of the second particles is b2, b1=b2.
  15. 15 . The preparation method for the positive electrode active material according to claim 9 , wherein the first particles are composed of primary particles having a size of R1, and the second particles are composed of primary particles having a size of R2, R1<R2.
  16. 16 . The preparation method for the positive electrode active material according to claim 15 , wherein R1≥0.85 R2.
  17. 17 . A lithium-ion battery, comprising the positive electrode active material according to claim 1 .

Description

This application is a continuation of International Application No. PCT/CN2024/119227, filed on Sep. 14, 2024, which claims priority to Chinese Patent Application No. 202311197498.0, filed on Sep. 15, 2023, both of which are hereby incorporated by reference in their entireties. TECHNICAL FIELD This present application relates to a positive electrode material, a preparation method thereof and a lithium-ion battery, and relates to the technology field of lithium-ion batteries. BACKGROUND Lithium-ion batteries are secondary batteries that primarily rely on the movement of lithium ions between a positive electrode and a negative electrode to work. Positive electrode active materials are a decisive factor for the performance of lithium-ion batteries and directly determine the comprehensive performance of lithium-ion batteries. Ternary positive electrode active materials, such as lithium nickel cobalt manganese oxide (NCM) and lithium nickel cobalt aluminum oxide (NCA), are currently research hotspots among positive electrode active materials. However, among existing materials, the cycling stability of ternary positive electrode active materials remains to be improved. SUMMARY The present application provides a positive electrode active material and a preparation method thereof for improving the structural stability of ternary positive electrode active materials and improving the cycling performance of lithium-ion batteries. The present application further provides a lithium-ion battery including the above-mentioned positive electrode active material, which exhibits good cycling performance. A first aspect of the present application provides a positive electrode active material, where a chemical composition of the positive electrode active material is Li1+a[NixCoyM1zM2b]O2±cAd, 0<a<0.2, 0.5≤x<1, 0<y<0.3, 0<z<0.3, 0<b<0.2, c<0.02, 0≤d≤0.05, and x+y+z+b=1; M1 is one or two of Mn or Al, M2 is one or more of Zr, Mg, Ti, Te, Al, Ca, Sr, Sb, Nb, Pb, V, Ge, Se, W, Mo, Zn, Ce, or Y; and A is one of F, Cl, or S;a X value corresponding to Ni element in the chemical composition of first particles is X1, and a X value corresponding to Ni element in the chemical composition of second particles is X2, 0.005≤(X1-X2)≤0.07;the first particles refer to particles having an average size equal to D10 of an overall particle size distribution of the positive electrode active material, and the second particles refer to particles having an average size equal to D90 of the overall particle size distribution of the positive electrode active material. In an embodiment, a Y value corresponding to Co element in the chemical composition of the first particles is Y1, and a Y value corresponding to Co element in the chemical composition of the second particles is Y2, Y2>Y1. In an embodiment, (X1-X2)> (Y2-Y1). In an embodiment, a Z value corresponding to M1 element in the chemical composition of the first particles is Z1, and a Z value corresponding to M1 element in the chemical composition of the second particles is Z2, Z2>Z1. In an embodiment, (X1-X2)> (Z2-Z1). In an embodiment, a b value corresponding to M2 element in the chemical composition of the first particles is b1, and a b value corresponding to M2 element in the chemical composition of the second particles is b2, b1=b2. In an embodiment, the first particles are composed of primary particles having a size of R1, and the second particles are composed of primary particles having a size of R2, R1<R2. In an embodiment, R1≥0.85 R2. A second aspect of the present application provides a preparation method for the positive electrode active material as described above, including the following steps: mixing a nickel source, a cobalt source, and an M1 source to prepare a positive electrode active material precursor; the positive electrode active material precursor includes a first positive electrode active material precursor and a second positive electrode active material precursor,where the first positive electrode active material precursor has size smaller than that of the second positive electrode active material precursor; a molar content of Ni element in a chemical composition of the first positive electrode active material precursor is W1, and a molar content of Ni element in the chemical composition of the second positive electrode active material precursor is W2, W1-W2≥0.005;mixing the positive electrode active material precursor, a lithium source, and an M2 source to form a mixed material;sintering the mixed material in an oxygen or air atmosphere to obtain the positive electrode active material. A third aspect of the present application provides a lithium-ion battery including the positive electrode active material as described above. The present application provides a positive electrode active material. By controlling the Ni content in particles of different particle sizes, the problem of non-uniform degradation of the secondary particles of different particle sizes during battery cycli