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JP-2026514541-A - Cathode material precursor, single crystal cathode material, and manufacturing method, lithium-ion battery

JP2026514541AJP 2026514541 AJP2026514541 AJP 2026514541AJP-2026514541-A

Abstract

A cathode material precursor, a single-crystal cathode material, and a method for producing it, and a lithium-ion battery, wherein the general chemical formula of the single-crystal cathode material is Li x Ni a Co b Mn c N d O 2 , where 0.98 ≤ x ≤ 1.1, 0.50 ≤ a ≤ 0.98, 0 < b ≤ 0.20, 0 < c ≤ 0.30, 0 ≤ d ≤ 0.10, a + b + c + d = 1, N comprises at least one of Al, Ti, Zr, Mg, Sr, Ba, Ca, Nb, W, Sb, Ta, Sn, and Y, the standard deviation of the mass content of each element Ni, Co, and Mn in the single-crystal cathode material is all ≤ 0.03, and the crystal lattice strain is ε < 0.2%. The aforementioned single-crystal cathode material has low crystal lattice strain, which reduces the diffusion energy barrier between lithium ions into the microcrystals, allowing the material to exhibit a low DCR, resulting in high rate characteristics, suppression of the occurrence of fine cracks, and improved cycle performance of the material. [Selection Diagram] Figure 4

Inventors

  • 劉国学
  • 万基平
  • 鄭玉
  • 饒響響
  • 呉小珍
  • 楊順毅
  • 黄友元

Assignees

  • 深▲セン▼市貝特瑞納米科技有限公司

Dates

Publication Date
20260511
Application Date
20240929
Priority Date
20231013

Claims (15)

  1. A single-crystal cathode material, the general chemical formula of the single-crystal cathode material is Li x Ni a Co b Mn c N d O 2 , where 0.98 ≤ x ≤ 1.1, 0.50 ≤ a ≤ 0.98, 0 < b ≤ 0.20, 0 < c ≤ 0.30, 0 ≤ d ≤ 0.10, a + b + c + d = 1, and N comprises at least one of Al, Ti, Zr, Mg, Sr, Ba, Ca, Nb, W, Sb, Ta, Sn, and Y. When the single-crystal cathode material is observed with a scanning electron microscope, 10 points are randomly selected from the single-crystal cathode material at a magnification of 3K and EDS point scanning is performed to measure the Ni, Co, and Mn content. In the EDS spectral results of the single-crystal cathode material, the standard deviations of the mass content of each element, Ni, Co, and Mn, in the single-crystal cathode material are all ≤0.03. The single-crystal cathode material is characterized in that the crystal lattice strain of the single-crystal cathode material is ε and ε < 0.2%.
  2. The single-crystal cathode material according to claim 1 , wherein the single- crystal cathode material contains SO₄²⁻ , and the content of SO₄²⁻ is δ, where 0 ppm ≤ δ ≤ 800 ppm.
  3. The single-crystal cathode material according to claim 1, characterized in that the single-crystal cathode material comprises at least one single crystal grain having the same orientation, wherein the average particle size of the single crystal grain is 1 μm to 5 μm.
  4. The single-crystal cathode material according to claim 1, characterized in that the mass content range of each element, Ni, Co, and Mn, in the single-crystal cathode material is all ≤0.08.
  5. The single-crystal cathode material according to claim 1, further comprising a coating layer, wherein the coating layer comprises a metal oxide or a lithium-ion conductor, and the metal in the metal oxide comprises at least one of Al, Ti, Zr, Y, Nb, Mg, W, B, Ce, Co, and Mn.
  6. The aforementioned single-crystal cathode material is (1) The dimensions of the crystal grains of the single-crystal cathode material are D, and the characteristics are that 150 nm < D < 250 nm. (2) The average particle size D 50 of the single-crystal cathode material is 1.5 μm to 5 μm. (3) The single crystal cathode material according to any one of claims 1 to 5, characterized in that it satisfies at least one of the following features: the better tap density of the single crystal cathode material is >1.5 g/cm³ .
  7. The aforementioned single-crystal cathode material is (1) The average particle size D 50 of the single-crystal cathode material is 3.0 to 4.5 μm. (2) The single-crystal cathode material has a compaction density of 1.68 to 2.2 g/ cm³ . (3) The single crystal cathode material according to claim 6, characterized in that the general chemical formula of the single crystal cathode material contains at least one of the following: LiNi 0.67 Co 0.05 Mn 0.28 O 2 , LiNi 0.88 Co 0.06 Mn 0.04 O 2 , or LiNi 0.88 Co 0.06 Mn 0.03 Al 0.03 O 2 .
  8. A positive electrode material precursor, the general chemical formula of the positive electrode material precursor is Ni a Co b Mn c N d O e , where 0.50 ≤ a ≤ 0.98, 0 < b ≤ 0.20, 0 < c ≤ 0.30, 0 ≤ d ≤ 0.10, a + b + c + d = 1, 1 ≤ e ≤ 1.15, and N comprises at least one of Al, Ti, Zr, Mg, Sr, Ba, Ca, Nb, W, Sb, Ta, Sn, and Y. A positive electrode material precursor characterized in that the weighted average diameter of the surface area of the positive electrode material precursor is D[3,2] < 2.0 μm, and the standard deviations of the mass content of each element, Ni, Co, and Mn, in the positive electrode material precursor are all ≤ 0.05.
  9. The positive electrode material precursor according to claim 8, wherein the positive electrode material precursor contains SO₄²⁻ , and the content of SO₄²⁻ is η, where 0 ppm ≤ η ≤ 1800 ppm.
  10. The cathode material precursor according to claim 8, characterized in that the mass content range of each element, Ni, Co, and Mn, in the cathode material precursor is all ≤0.12.
  11. The aforementioned cathode material precursor is (1) The positive electrode material precursor has the technical characteristic of containing secondary particles, and the secondary particles contain a plurality of aggregated primary particles. (2) The positive electrode material precursor contains secondary particles, the secondary particles contain a plurality of aggregated primary particles, and the primary particles have the technical characteristic of being spherical. (3) The cathode material precursor according to claim 8, characterized in that the cathode material precursor satisfies at least one of the following technical features: the cathode material precursor comprises secondary particles, the secondary particles comprise a plurality of aggregated primary particles, and the particle size of the primary particles is 20 nm to 1000 nm.
  12. The aforementioned cathode material precursor is (1) The technical characteristic is that the average particle size D 50 of the positive electrode material precursor is <3.5 μm. (2) The specific surface area of the cathode material precursor is >5 m² /g, which is a technical characteristic. (3) The positive electrode material precursor according to claim 8 , which satisfies at least one of the following technical features: the better tap density of the positive electrode material precursor is >1 g/cm³.
  13. A method for manufacturing a single-crystal cathode material, The process involves atomizing a mixed solution containing nickel salt, cobalt salt, and manganese salt, followed by thermal decomposition to obtain a positive electrode material precursor, wherein the surface area weighted average diameter of the positive electrode material precursor is D[3,2] < 2.0 μm, and the standard deviations of the mass content of each element Ni, Co, and Mn in the positive electrode material precursor are all ≤ 0.05. A method for producing a single-crystal cathode material, comprising the steps of: mixing the cathode material precursor with a lithium source, sintering in an oxygen-containing atmosphere to obtain a single-crystal cathode material; wherein the standard deviations of the mass content of each element Ni, Co, and Mn in the single-crystal cathode material are all ≤0.03, and the crystal lattice strain of the single-crystal cathode material is ε and ε < 0.2%.
  14. (1) The molar ratio of Ni, Co, and Mn in the mixed solution is (50-98):(0-20):(0-30), and the content of Co and Mn in the mixed solution is not 0. (2) The total metal concentration in the mixed solution is 200 g/L to 500 g/L. (3) The mixed solution further contains an N-containing dopant, wherein N contains at least one of Al, Ti, Zr, Mg, Sr, Ba, Ca, Nb, W, Sb, Ta, Sn, and Y. (4) The general chemical formula of the positive electrode material precursor is Ni a Co b Mn c N d O e , where 0.50 ≤ a ≤ 0.98, 0 < b ≤ 0.20, 0 < c ≤ 0.30, 0 ≤ d ≤ 0.10, a + b + c + d = 1, 1 ≤ e ≤ 1.15, and N contains at least one of Al, Ti, Zr, Mg, Sr, Ba, Ca, Nb, W, Sb, Ta, Sn, and Y. (5) The flow rate of the mixed solution is 100 L/h to 900 L/h. (6) The pressure of the atomization treatment is characterized by being 0.4 MPa to 0.8 MPa. The manufacturing method according to 13, characterized in that it includes at least one of the following features: (7) the temperature of the thermal decomposition is 500°C to 850°C.
  15. A lithium-ion battery characterized in that the lithium-ion battery includes a single-crystal cathode material described in any one of claims 1 to 12 or a single-crystal cathode material manufactured by a method for manufacturing a single-crystal cathode material described in any one of claims 13 or 14.

Description

This application relates to the field of cathode material technology, and more particularly to cathode material precursors, single-crystal cathode materials, manufacturing methods, and lithium-ion batteries. Lithium-ion cathode materials are mainly divided into lithium iron phosphate and ternary materials. Lithium iron phosphate is superior to ternary materials in terms of cost, cycle life, and thermal stability, making it suitable for applications in commercial vehicles, mid-range and low-end passenger cars, and energy storage. Ternary materials have high energy density and excellent low-temperature performance, making them suitable for mid-range and high-end passenger cars. Conventional polycrystalline ternary cathode materials are constructed by tightly aggregating primary particles (hundreds of nanometers) to form spherical secondary particles (usually particle size > 10 μm). During the charge-discharge process, as the crystal lattice shrinks, localized stress is easily generated along the grain boundaries, causing the material structure to collapse, forming fine cracks and rapidly reducing the capacitance of the cathode material. Single crystallization is one method to improve the cycle performance of ternary materials. Single-crystal ternary materials are composed of dispersed primary particles (generally several micrometers in diameter, and most particles are single crystal grains with the same orientation), and there are no secondary spherical particles. Because grain boundaries are eliminated, cracking of the cathode material during the charge-discharge process can be suppressed, and it exhibits excellent stability. However, single-crystal ternary materials also face other problems. Due to the long diffusion path of Li in single-crystal ternary materials, the transmission power of Li is slow, resulting in a large DC internal resistance (DCR) and poor rate characteristics. Furthermore, while single-crystal grains can suppress particle cracking, phenomena such as crystal plane slippage and displacement still occur during the cycle process, leading to the formation of even finer cracks. Ternary single-crystal cathode materials are generally manufactured by high-temperature sintering from a precursor compound containing Ni/Co/Mn and a lithium salt. During the sintering process, the formation of the cathode material is usually very slow and the growth rate is non-uniform, leading to stress concentration within the formed cathode material. Furthermore, ion diffusion is limited, resulting in concentration differences in the elemental distribution within the ternary material and mismatched crystal lattice parameters within the material. This inhibits lithium ion transmission, increasing the resistance of the cathode material and degrading its rate characteristics. Additionally, minute stresses in the internal crystal lattice cause cracking and pulverization during the cathode material's cycling process, further reducing its cycling performance. Therefore, improving the rate characteristics of single-crystal cathode materials, reducing resistance, and further enhancing cycle performance are currently technical problems that need to be solved. The present application will be further described below with reference to the drawings and embodiments. This is an SEM diagram of the cathode material precursor manufactured in Example 1 of the present application. This is another SEM morphological diagram of the cathode material precursor manufactured in Example 1 of the present application. This is the EDS spectrum result of the cathode material precursor manufactured in Example 1 of the present application. This is the Williamson-Hall analysis fitting curve for the single-crystal cathode material manufactured in Example 1 of the present application. To better understand the technical solution of this application, embodiments of this application will be described in detail below with reference to the drawings. Clearly, the embodiments described are only a subset of the embodiments of this application, not all of them. All other embodiments derived from the embodiments of this application, without the creative work of a person skilled in the art, are all within the scope of protection of this application. The terms used in the embodiments of this application are for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms “one,” “the said,” and “the said” used in the embodiments and the appended claims are intended to include the plural form unless otherwise indicated by the context. It should be understood that the terms "and/or" as used herein merely describe the relationship between related objects, and that three types of relationships may exist. For example, A and/or B can refer to three cases: A existing alone, A and B existing together, or B existing alone. Furthermore, in this specification, the letter "/" generally indicates that the preceding and succe