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US-20260125281-A1 - CATHODE MATERIAL AND PREPARATION METHOD THEREOF, LITHIUM-ION BATTERY, AND ELECTRICAL DEVICE

US20260125281A1US 20260125281 A1US20260125281 A1US 20260125281A1US-20260125281-A1

Abstract

The present disclosure belongs to the technical field of batteries, and specifically discloses a cathode material and a preparation method thereof, a lithium-ion battery, and an electrical device. The cathode material satisfies: 1.5<Kn 90 =(Ln 90 −Ln 10 )/Ln 50 <4.5; 0<Ln 10 <2000 Å; Ln 10 <Ln 50 <3000 Å; and Ln 50 <Ln 90 <15000 Å.

Inventors

  • Yiseng Hu
  • Mingjun Zhang
  • Haikuan FU
  • Shanshan Li
  • Shunlin SONG
  • Yafei Liu
  • Yanbin Chen

Assignees

  • BEIJING EASPRING MATERIAL TECHNOLOGY CO., LTD.

Dates

Publication Date
20260507
Application Date
20251223
Priority Date
20241107

Claims (20)

  1. 1 . A cathode material, wherein: 1. 5 < K ⁢ n 9 ⁢ 0 = ( Ln 9 ⁢ 0 - Ln 1 ⁢ 0 ) / Ln 5 ⁢ 0 < 4.5 ; 0 < L ⁢ n 1 ⁢ 0 < 2000 ⁢ Å ; L ⁢ n 1 ⁢ 0 < L ⁢ n 5 ⁢ 0 < 3000 ⁢ Å ; and L ⁢ n 5 ⁢ 0 < L ⁢ n 9 ⁢ 0 < 1 ⁢ 5 ⁢ 000 ⁢ Å , where: Ln 10 , Ln 50 , and Ln 90 are sub-grain sizes of the cathode material corresponding to number cumulative percentages of the sub-grain sizes Ln reaching 10%, 50%, and 90%, respectively, and K n90 is sub-grain size distribution of the cathode material.
  2. 2 . The cathode material according to claim 1 , wherein: 500 ⁢ Å < Ln 1 ⁢ 0 < 2000 ⁢ Å ; 2000 ⁢ Å < Ln 5 ⁢ 0 < 3000 ⁢ Å ; 5000 ⁢ Å < Ln 9 ⁢ 0 < 9000 ⁢ Å ; and 2.5 < Kn 9 ⁢ 0 < 4 . 0 .
  3. 3 . The cathode material according to claim 1 , wherein a particle size P satisfies 1.0 μm<P<2.0 μm.
  4. 4 . The cathode material according to claim 3 , wherein 1.3 μm<P<1.7 μm.
  5. 5 . The cathode material according to claim 1 , wherein the cathode material has a volume distribution median particle size of D′50, where 1 μm<D′50<4 μm.
  6. 6 . The cathode material according to claim 1 , comprising a composition represented by Formula I: where: 0 ≤ a ≤ 0.2 ; 0 ≤ b ≤ 0 .05 ; 0 ≤ c ≤ 0 .05 ; 0.4 ≤ x < 1 ; 0 < y < 0 .15 ; 0 ≤ z < 0.5 ; element G comprises at least one of Zr, Ti, Y, W, Al, Nb, or Sr; and element M comprises at least one of La, Zr, B, Nb, Ti, W, Si, Mg, or Al.
  7. 7 . The cathode material according to claim 6 , comprising: a matrix; and a coating layer, wherein: the coating layer is disposed on at least a portion of a surface of the matrix; and the element M is mainly located in the coating layer.
  8. 8 . The cathode material according to claim 1 , wherein a concentration of element cobalt on a surface of particles of the cathode material is greater than a concentration of element cobalt inside the particles.
  9. 9 . The cathode material according to claim 8 , wherein in all metal elements other than lithium, a molar proportion of element cobalt is greater than 0% and less than or equal to 15%.
  10. 10 . The cathode material according to claim 8 , wherein in all metal elements other than lithium, a molar proportion of element cobalt is greater than 0% and less than or equal to 10%.
  11. 11 . A method for preparing the cathode material according to claim 1 , the method comprising: mixing a nickel-cobalt-manganese precursor and a lithium salt to obtain a raw material mixture, and performing a first sintering on the raw material mixture in an oxygen-containing atmosphere at a temperature ranging from 700° C. to 1000° C. for 6 hours to 12 hours, to obtain an intermediate product; and mixing the intermediate product, a lithium source, and a cobalt source to obtain an intermediate product mixture, and performing a second sintering on the intermediate product mixture in an oxygen-containing atmosphere at a temperature ranging from 300° C. to 800° C. for 6 hours to 12 hours, to obtain the cathode material, wherein a molar ratio of element lithium in the lithium source to element cobalt in the cobalt source is Y, where 0.5<Y<1.4.
  12. 12 . The method according to claim 11 , wherein 0.8<Y<1.2.
  13. 13 . The method according to claim 11 , wherein the lithium salt comprises at least one of lithium carbonate or lithium hydroxide.
  14. 14 . The method according to claim 13 , wherein the lithium salt comprises a mixed lithium salt of lithium carbonate and lithium hydroxide.
  15. 15 . The method according to claim 14 , wherein the lithium salt comprises the mixed lithium salt of lithium carbonate and lithium hydroxide with a molar ratio of element lithium in the lithium carbonate to element lithium in the lithium hydroxide ranging from 3:7 to 8:2.
  16. 16 . The method according to claim 11 , wherein a molar ratio of element cobalt in the cobalt source to a sum of elements nickel, cobalt, and manganese in the cathode material is less than 5%.
  17. 17 . The method according to claim 11 , wherein the nickel-cobalt-manganese precursor has a volume distribution median particle size of D50, where 1 μm<D50<3.5 μm.
  18. 18 . The method according to claim 11 , satisfying at least one of the following conditions: the raw material mixture further comprises a compound containing element G; or the intermediate product mixture further comprises a compound containing element M, and satisfying at least one of the following conditions: the nickel-cobalt-manganese precursor comprises at least one of nickel-cobalt-manganese oxide or nickel-cobalt-manganese hydroxide; the compound containing element G comprises at least one of an oxide, hydroxide or carbonate of the element G, wherein the element G comprises at least one of Zr, Ti, Y, W, Al, Nb, or Sr; the cobalt source comprises at least one of cobalt oxide, cobalt tetraoxide, cobalt oxyhydroxide, or cobalt hydroxide; the lithium source comprises at least one of lithium carbonate, lithium hydroxide, lithium phosphate, or lithium dihydrogen phosphate; or the compound containing element M comprises at least one of an oxide, hydroxide or carbonate of the element M, wherein the element M comprises at least one of La, Zr, B, Nb, Ti, W, Si, Mg, or Al.
  19. 19 . A lithium-ion battery, comprising the cathode material according to claim 1 .
  20. 20 . An electrical device, comprising the lithium-ion battery according to claim 19 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of International Application No. PCT/CN2024/142823, filed on Dec. 26, 2024, which claims priority and benefits to the Chinese patent application No. 202411586363.8 filed with the China National Intellectual Property Administration on Nov. 7, 2024. The disclosures of the aforementioned applications are herein incorporated by reference in their entireties. FIELD The present disclosure belongs to the technical field of batteries, and particularly relates to a cathode material and a preparation method thereof, a lithium-ion battery, and an electrical device. BACKGROUND In recent years, lithium iron phosphate materials have occupied a dominant position in the domestic battery field due to their absolute cost advantage and good safety, and have broad development prospects. However, lithium iron phosphate materials per se still have shortcomings: the polarity of phosphate is too strong, and the ability to bind lithium is too strong, resulting in a low diffusion coefficient, which affects the charge and discharge performance in low-temperature environments, making low-temperature performance, in particular at low battery charge (SOC) states, poor. In order to meet special application scenarios such as low temperature, some companies still choose to use more expensive ternary materials to prepare batteries. Although the low-temperature performance of the ternary materials is better than that of lithium iron phosphate materials, with the increasingly stringent market demand, the low-temperature performance of the materials still needs to be further improved on the existing basis. At low temperatures, the diffusion coefficient of lithium ions inside the ternary material decreases, and the energy required for charge transfer increases, which manifests as high low-temperature impedance and poor low-temperature discharge capability. In the related technology, the low-temperature performance is improved by increasing the cobalt content or introducing solid electrolyte coating, but both of these methods will cause a significant increase in material costs, thereby reducing market competitiveness. Therefore, the low-temperature performance of cathode materials still needs to be further improved. SUMMARY In a first aspect, the present disclosure provides a cathode material that satisfies: 1.5<Kn90=(Ln90−Ln10)/Ln50<4.5; 0<Ln10<2000 Å; Ln10<Ln50<3000 Å; and Ln50<Ln90<15000 Å, where: Ln10, Ln50, and Ln90 are sub-grain sizes of the cathode material corresponding to number cumulative percentages of the sub-grain sizes Ln reaching 10%, 50%, and 90%, respectively, and Kn90 is sub-grain size distribution of the cathode material. In a second aspect, the present disclosure provides a method for preparing the cathode material. The method includes: mixing a nickel-cobalt-manganese precursor and a lithium salt to obtain a raw material mixture, and performing a first sintering on the raw material mixture in an oxygen-containing atmosphere at a temperature ranging from 700° C. to 1000° C. for 6 hours to 12 hours, to obtain an intermediate product; and mixing the intermediate product, a lithium source, and a cobalt source to obtain an intermediate product mixture, and performing a second sintering on the intermediate product mixture in an oxygen-containing atmosphere at a temperature ranging from 300° C. to 800° C. for 6 hours to 12 hours, to obtain the cathode material. A molar ratio of element lithium in the lithium source to element cobalt in the cobalt source is Y, where 0.5<Y<1.4. In a third aspect, the present disclosure provides a lithium-ion battery. The lithium-ion battery includes the cathode material according to the first aspect. In a fourth aspect, the present disclosure provides an electrical device. The electrical device includes the lithium-ion battery according to the third aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electron microscope image of a finished product of cathode material in Example 1 of the present disclosure. FIG. 2 is an electron microscope image of a finished product of cathode material in Example 5 of the present disclosure. FIG. 3 is an electron microscope image of a finished product of cathode material in Example 6 of the present disclosure. FIG. 4 is an electron microscope image of a finished product of cathode material in Comparative Example 1 of the present disclosure. FIG. 5 is a sub-grain size distribution graph of finished products of cathode materials in Example 1, Example 9, and Comparative Example 1 of the present disclosure. DETAILED DESCRIPTION Embodiments of the present disclosure will now be described in detail, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present disclosure but should not be construed as limiting the present disclosure. The pre