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EP-4738468-A1 - CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY COMPRISING SAME

EP4738468A1EP 4738468 A1EP4738468 A1EP 4738468A1EP-4738468-A1

Abstract

The present embodiments relate to a positive electrode active material for a lithium secondary battery and a lithium secondary battery including the same. A positive electrode active material for a lithium secondary battery according to one embodiment includes a nickel-containing metal oxide in a single-particle form and a doping element doped into the nickel-containing metal oxide, wherein the doping element may include Al, Y, and Zr.

Inventors

  • LEE, SUBIN
  • MYUNG, Minhoon
  • SIM, Sung Keun
  • LEE, SEUNGWON
  • CHOI, KWONYOUNG

Assignees

  • Posco Future M Co., Ltd.

Dates

Publication Date
20260506
Application Date
20240626

Claims (14)

  1. A positive electrode active material for a lithium secondary battery, comprising: a nickel-containing metal oxide in a single-particle form; and a doping element doped into the nickel-containing metal oxide, wherein the doping element comprises Al, Y, and Zr.
  2. The positive electrode active material of claim 1, wherein a cation mixing ratio of nickel cations in a lithium layer of a crystal structure of the doped nickel-containing metal oxide is 1.5% or less.
  3. The positive electrode active material of claim 1, wherein a content of Al is from 200 ppm to 1,800 ppm based on the nickel-containing metal oxide.
  4. The positive electrode active material of claim 1, wherein a content of Y is from 400 ppm to 2,000 ppm based on the nickel-containing metal oxide.
  5. The positive electrode active material of claim 1, wherein a content of Zr is from 1,200 ppm to 2,800 ppm based on the nickel-containing metal oxide.
  6. The positive electrode active material of claim 1, wherein a content of nickel is 0.8 mol or more based on a total of 1 mol of transition metals included in the nickel-containing metal oxide.
  7. The positive electrode active material of claim 1, wherein the nickel-containing metal oxide further comprises cobalt, and a content of cobalt is 0.06 mol or less based on a total of 1 mol of transition metals contained in the doped nickel-containing metal oxide.
  8. The positive electrode active material of claim 7, wherein the nickel-containing metal oxide further comprises manganese, and a content of manganese is 0.15 mol or less based on a total of 1 mol of transition metals contained in the nickel-containing metal oxide.
  9. The positive electrode active material of claim 1, wherein the nickel-containing metal oxide is represented by Chemical Formula 1 below: [Chemical Formula 1] Li a [Ni x Co γ Mn z M 1 W1 M 2 W2 ]O 2 wherein 0.8 ≤ a ≤ 1.2, 0.8 ≤ x ≤ 0.99, 0 < y ≤ 0.06, 0 < z ≤ 0.14, 0 < w 1 ≤ 0.05, 0 ≤ w 2 ≤ 0.05, and x + y + z + w 1 + w 2 = 1, wherein M 1 is Al, Y, and Zr, and M 2 comprises one or more selected from B, Al, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La, and Sr.
  10. The positive electrode active material of claim 1, wherein an average particle diameter (D50) of the positive electrode active material is 3 µm or more.
  11. The positive electrode active material of claim 1, wherein, when five pressurizations are performed using a roll press at a press gauge of 0.01 mm, a total amount of fine particles having a size of less than 1 µm is 2 vol% or less.
  12. The positive electrode active material of claim 1, wherein a peak temperature obtained by differential scanning calorimetry (DSC) analysis is 230°C or higher.
  13. A positive electrode for a lithium secondary battery comprising the positive electrode active material according to any one of claims 1 to 12.
  14. A lithium secondary battery comprising the positive electrode of claim 13.

Description

[Technical Field] The present embodiments relate to a positive electrode active material for a lithium secondary battery and a lithium secondary battery including the same. [Background Art] Recently, driven by the explosive demand for electric vehicles and the increasing need for longer driving ranges, the development of secondary batteries having high capacity and high energy density has been actively pursued worldwide. In particular, to satisfy such demands, high-nickel NCM positive electrode materials have been widely employed. However, as the nickel content increases, the particle strength decreases, resulting in the generation of microcracks during charge and discharge. In addition, the specific surface area of the positive electrode material increases, which increases reactions with the electrolyte, thereby causing an increase in gas generation. Further, due to structural instability, unstable Ni3+ is reduced to stable Ni2+ and converts into stable NiO, thereby increasing cation mixing. Accordingly, applying such materials as positive electrode active materials for lithium-ion batteries used in electric vehicles or energy-storage systems is difficult. To address these issues, approaches have been proposed in which the positive electrode material is manufactured not in a multi-particle structure, i.e., secondary particles formed by agglomerated primary particles, but instead in a single-particle form in which the size of the primary particle is maximized. However, to manufacture a positive electrode material in a single-particle form, calcination must generally be performed at a higher temperature compared to multi-particle systems. In such cases, over-sintering frequently occurs, causing defects in the layered crystal structure, which deteriorates electrochemical characteristics such as capacity and output, and increases resistance. [Detailed Description of the Invention] [Technical Problem] The present embodiments aim to provide a positive electrode active material for a lithium secondary battery that exhibits excellent electrochemical performance while also providing improved lifespan and resistance characteristics, and having superior particle strength. A lithium secondary battery including the same is also provided. [Technical Solution] According to one embodiment, a positive electrode active material for a lithium secondary battery includes a nickel-containing metal oxide in a single-particle form and a doping element doped into the nickel-containing metal oxide, wherein the doping element may include Al, Y, and Zr. According to another embodiment, a positive electrode for a lithium secondary battery may include the positive electrode active material according to the one embodiment. According to still another embodiment, a lithium secondary battery may include the positive electrode for a lithium secondary battery according to the one embodiment. [Effects of the Invention] According to the present embodiments, by doping at least three doping elements-specifically Al, Y, and Zr-into a nickel-containing metal oxide in a single-particle form, the crystal structure can be stabilized and the particle strength can be improved. Accordingly, the present embodiments enable the realization of a positive electrode active material in a single-particle form that exhibits excellent electrochemical performance and improved lifespan and resistance characteristics. [Mode for Carrying Out the Invention] The terms "first," "second," "third," and the like used herein are employed to describe various parts, components, regions, layers, and/or sections but are not limited thereto. These terms are only used to distinguish one part, component, region, layer, or section from another. Therefore, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention. Technical terminology used herein is intended only to describe specific embodiments and is not intended to limit the present invention. Singular forms used herein include plural forms unless the context clearly indicates otherwise. The term "comprising/including/containing" as used in the specification specifies the presence of stated features, regions, integers, steps, operations, elements, and/or components, but does not preclude the presence or addition of other features, regions, integers, steps, operations, elements, and/or components. When a portion is described as being "on" or "over/above" another portion, it may be directly on or over the other portion, or intervening portions may be present therebetween. In contrast, when a portion is described as being "directly on" another portion, no intervening portion exists therebetween. Unless otherwise defined, all terms including technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this invention pertains.