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JP-7855032-B2 - Positive electrode active material, method for manufacturing the same, positive electrode containing the same, and lithium secondary battery

JP7855032B2JP 7855032 B2JP7855032 B2JP 7855032B2JP-7855032-B2

Inventors

  • 金 榮 基
  • 鄭 在 容
  • 秋 聲 浩
  • 孔 泳 善
  • 康 碩 文
  • 尹 在 祥
  • 杜 成 旭
  • 姜 貴 云
  • 全 道 ▲ウク▼
  • 姜 秉 旭

Assignees

  • 三星エスディアイ株式会社

Dates

Publication Date
20260507
Application Date
20240805
Priority Date
20230803

Claims (20)

  1. Core particles containing a lithium nickel- manganese composite oxide, wherein the nickel content is 60 mol% or more and the manganese content is 10 mol% to 40 mol% relative to 100 mol% of the total metal excluding lithium, and a coating layer located on the surface of the core particles, containing Al, Zr, and Mg . A positive electrode active material wherein the Al content of the coating layer is 0.1 mol% to 2 mol%, the Zr content of the coating layer is 0.1 mol% to 0.4 mol%, and the Mg content of the coating layer is 0.1 mol% to 0.5 mol% .
  2. The positive electrode active material according to claim 1, wherein the ratio of Zr and Mg content to Al content in the coating layer is 0.1 to 0.65.
  3. The positive electrode active material according to claim 1, wherein the coating layer has a shell shape that continuously surrounds the surface of the core particles.
  4. The positive electrode active material according to claim 1, wherein the thickness of the coating layer is 5 nm to 500 nm.
  5. The positive electrode active material according to claim 1, wherein the coating layer further comprises nickel, manganese, or a combination thereof.
  6. The positive electrode active material according to claim 1, wherein the lithium nickel- manganese composite oxide of the core particles has a nickel content of 60 mol% to 80 mol% relative to 100 mol% of the total metal excluding lithium.
  7. The lithium nickel- manganese composite oxide of the core particles is a lithium nickel-manganese- aluminum composite oxide that further contains aluminum in addition to nickel and manganese. The positive electrode active material according to claim 1, wherein the aluminum content in the lithium nickel-manganese- aluminum composite oxide is 1 mol% to 3 mol% relative to 100 mol% of the total metal excluding lithium.
  8. The lithium nickel- manganese composite oxide of the core particles is represented by the following chemical formula 1, and is the positive electrode active material according to claim 1: [Chemical formula 1] Li a1 Ni x1 Mn y1 Al z1 M 1 w1 O 2-b1 X b1 In chemical formula 1, 0.9 ≤ a1 ≤ 1.8, 0.6 ≤ x1 ≤ 0.8, 0.1 ≤ y1 ≤ 0.4, 0 ≤ z1 ≤ 0.03, 0 ≤ w1 ≤ 0.3, 0.9 ≤ x1 + y1 + z1 + w1 ≤ 1.1, and 0 ≤ b1 ≤ 0.1, where M1 is one or more elements selected from B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, and Zr, and X is one or more elements selected from F, P, and S.
  9. The positive electrode active material according to claim 8 , wherein in the chemical formula 1, 0.6 ≤ x1 ≤ 0.8, 0.1 ≤ y1 ≤ 0.39, 0.01 ≤ z1 ≤ 0.03, and 0 ≤ w1 ≤ 0.29.
  10. The positive electrode active material according to claim 1, wherein the cobalt content is 0 mol% to 0.01 mol% relative to 100 mol% of the total metal excluding lithium.
  11. The positive electrode active material according to claim 1, wherein the core particles are in a secondary particle form formed by the aggregation of a plurality of primary particles.
  12. The positive electrode active material according to claim 11 , further comprising a grain boundary coating portion containing Al, located on the surface of a primary particle inside the secondary particle.
  13. The positive electrode active material according to claim 12 , wherein the Al content in the grain boundary coating portion is less than the Al content in the coating layer.
  14. The positive electrode active material according to claim 12 , wherein the grain boundary coating portion further contains Mg.
  15. The positive electrode active material according to claim 1, wherein the average particle size (D 50 ) of the positive electrode active material is 10 μm to 18 μm.
  16. The positive electrode active material according to claim 1, wherein the positive electrode active material does not contain sodium.
  17. A nickel- manganese composite hydroxide having a nickel content of 60 mol% or more and a manganese content of 10 mol% to 40 mol% relative to 100 mol% of the total metal is mixed with a lithium raw material and subjected to a first heat treatment to obtain a lithium nickel- manganese composite oxide. After adding the obtained lithium nickel- manganese composite oxide to a solution in which Al raw materials were mixed in an aqueous solvent and mixing, the mixture was dried. A method for producing a positive electrode active material, comprising dry mixing the obtained material with a Zr raw material and an Mg raw material and performing a second heat treatment to obtain a positive electrode active material.
  18. The Al content in the aforementioned Al raw material is 0.1 mol% to 2 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material. The Zr content in the Zr raw material is 0.1 mol% to 0.4 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material. The method for producing a positive electrode active material according to claim 17 , wherein the Mg content in the Mg raw material is 0.1 mol% to 0.5 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.
  19. The aforementioned Al raw material includes aluminum nitrate, aluminum sulfate, aluminum carbonate, aluminum hydroxide, or a combination thereof. The Zr raw material includes zirconium oxide, zirconium silicate, or a combination thereof. The method for producing a positive electrode active material according to claim 17 , wherein the Mg raw material includes magnesium oxide, magnesium phosphate, magnesium carbonate, or a combination thereof.
  20. The method for producing a positive electrode active material according to claim 17 , wherein the solution obtained by mixing an aluminum raw material with the aqueous solvent has a pH of 1.5 to 3.5.

Description

This invention relates to a positive electrode active material, a method for producing the same, a positive electrode containing the same, and a lithium secondary battery. Lithium-ion batteries, which offer high energy density while remaining easily portable, are primarily used as power sources for mobile information terminals such as mobile phones, laptops, and smartphones. Recently, research is actively underway to utilize high-energy-density lithium-ion batteries as power sources or energy storage devices for hybrid and electric vehicles. To realize lithium secondary batteries that meet these applications, a variety of positive electrode active materials are being considered. Among these, lithium nickel oxides, lithium nickel manganese cobalt composite oxides, lithium nickel cobalt aluminum composite oxides, and lithium cobalt oxides are primarily used as positive electrode active materials. However, in recent years, while the demand for large, high-capacity, or high-energy-density lithium secondary batteries has surged, the supply of positive electrode active materials containing cobalt, a rare metal, is expected to be severely insufficient. In other words, because cobalt is expensive and its remaining reserves are limited, development of positive electrode active materials that either exclude cobalt or reduce its cobalt content is necessary. This is a schematic cross-sectional view showing a lithium secondary battery according to one embodiment. The following describes specific embodiments in detail so that those with ordinary skill in the art can easily implement them. However, the present invention can be realized in various different forms and is not limited to the embodiments described herein. The terms used herein are for illustrative purposes only and are not intended to limit the invention. Unless otherwise clearly indicated in the context, singular expressions include plural expressions. Here, "these combinations" refers to mixtures of constituents, laminates, composites, copolymers, alloys, blends, reaction products, etc. Here, terms such as "include," "possess," or "have" are intended to specify the existence of implemented features, figures, stages, components, or combinations thereof, and should be understood not to presuppose the existence or possibility of adding one or more other features, figures, stages, components, or combinations thereof. To clearly represent various layers and regions in the drawings, thicknesses are shown enlarged, and similar parts are given the same drawing reference numerals throughout the specification. When a layer, film, region, plate, or other part is described as being "on top of" or "on" another part, this includes not only when it is "directly on top of" another part, but also when there is another part in between. Conversely, when a part is described as being "directly on top of" another part, it means that there is no other part in between. Furthermore, here, "layer" includes not only the shapes formed on the entire surface when observed in a plan view, but also shapes formed on a portion of the surface. The average particle size can be measured by methods widely known to those skilled in the art, such as using a particle size analyzer or by measuring transmission electron microscope images or scanning electron microscope images. Alternatively, it can be measured using dynamic light scattering, and after performing data analysis to count the number of particles for each particle size range, the average particle size value can be calculated. Unless otherwise defined, the average particle size refers to the diameter (D50) of the particle whose cumulative volume in the particle size distribution is 50% by volume. Furthermore, unless otherwise defined, the average particle size may be obtained by measuring the size (diameter or length of the major axis) of more than 20 randomly selected particles from a scanning electron microscope image to obtain a particle size distribution, and then taking the diameter (D50) of the particle whose cumulative volume in the said particle size distribution is 50% by volume as the average particle size. Here, "or" is not interpreted in an exclusive sense; for example, "A or B" is interpreted as including A, B, A + B, etc. The term "metal" is interpreted as a concept that includes general metals, transition metals, and metalloids (semimetals). One embodiment of a positive electrode active material provides core particles containing a lithium nickel-manganese composite oxide in which the nickel content is 60 mol% or more relative to 100 mol% of the total metal excluding lithium, and a coating layer located on the surface of the core particles and containing Al, Zr, and Mg. In recent years, with the sharp rise in the price of cobalt, a rare metal, there has been a demand for the development of cathode active materials that either exclude cobalt or reduce its cobalt content. Among these, cathode active materials with olivine-base