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EP-4742324-A1 - POSITIVE ELECTRODE ACTIVE MATERIAL, METHOD FOR PRODUCING SAME, AND POSITIVE ELECTRODE AND LITHIUM SECONDARY BATTERY COMPRISING SAME

EP4742324A1EP 4742324 A1EP4742324 A1EP 4742324A1EP-4742324-A1

Abstract

The present invention relates to a positive electrode active material that may improve the performance of a lithium secondary battery, and relates to a positive electrode active material comprising a lithium-rich manganese-based oxide comprising a Li 2 MnO 3 phase and a LiMO 2 (where M is an element comprising Ni, Mn or a combination thereof) phase at the same time, wherein the lithium-rich manganese-based oxide has a composition represented by Formula 1 described in the present description, a method for preparing the same, and a positive electrode and a lithium secondary battery comprising the same.

Inventors

  • YOON, JU HAN
  • JEONG, MYEONG SANG
  • KIM, WON TAE
  • LIM, YOUNG GEUN
  • LEE, SEONG NAM
  • SEOL, JAE SEUNG

Assignees

  • LG Chem, Ltd.

Dates

Publication Date
20260513
Application Date
20240806

Claims (12)

  1. A positive electrode active material comprising a lithium-rich manganese-based oxide comprising a Li 2 MnO 3 phase and a LiMO 2 (where M is an element comprising Ni, Mn or a combination thereof) phase at the same time, wherein the lithium-rich manganese-based oxide has a composition represented by the following Formula 1: [Formula 1] Li 1+x Ni a Mn b W c M 1 d O 2 in Formula 1, M 1 is one or more selected from Al, P, V, Y, Ti and Nb, 0.10≤x≤0.20, 0<a<0.5, 0.5≤b<1.0, 0<c<0.008, and 0≤d<0.005.
  2. The positive electrode active material according to claim 1, wherein a is 0.30 to 0.35.
  3. The positive electrode active material according to claim 1, wherein b is 0.55 to 0.60.
  4. The positive electrode active material according to claim 1, wherein c is 0.0005 to 0.007.
  5. The positive electrode active material according to claim 1, wherein the content of W is 800 ppm to 15,000 ppm on the basis of a total weight of the lithium-rich manganese-based oxide.
  6. The positive electrode active material according to claim 1, wherein the lithium-rich manganese-based oxide has a tap density of 1.5 g/cm 3 to 2.5 g/cm 3 .
  7. The positive electrode active material according to claim 1, wherein the lithium-rich manganese-based oxide has an average particle diameter (D 50 ) of 2 µm to 12 µm.
  8. A method for preparing the positive electrode active material according to claim 1, the method comprising: (A) a step of mixing a composite transition metal hydroxide, a lithium (Li)-containing raw material, and a tungsten (W)-containing raw material to prepare a mixture; and (B) a step of heat-treating the mixture to prepare a lithium-rich manganese-based oxide, wherein the heat-treating is performed under a temperature of 600°C to 1,000°C.
  9. The method for preparing the positive electrode active material according to claim 8, wherein the tungsten (W)-containing raw material is mixed in an amount of 1,000 ppm to 17,000 ppm on the basis of a total weight of the composite transition metal hydroxide.
  10. The method for preparing the positive electrode active material according to claim 8, wherein the heat-treating in step (B) is performed under an air atmosphere.
  11. A positive electrode comprising the positive electrode active material according to any one of claim 1 to claim 7.
  12. A lithium secondary battery comprising the positive electrode according to claim 11.

Description

TECHNICAL FIELD Cross-reference to Related Applications This application claims the benefit of Korean Patent Application No. 10-2023-0109714, filed on August 22, 2023, in the Korean Intellectual Property Office, the contents of which are incorporated herein by reference. Technical Field The present invention relates to a positive electrode active material, a method for preparing the same, and a positive electrode and a lithium secondary battery comprising the same. BACKGROUND ART Lithium secondary batteries are composed of four major components of a positive electrode, a negative electrode, a separator, and an electrolyte. Among them, a positive electrode active material included in the positive electrode plays a major role in determining the capacity, output, and lifespan of the battery. In order for lithium secondary batteries to have high energy density, output, and lifespan, it is essential to improve the performance of the positive electrode active material, and for this reason, much research has been conducted recently to develop high-performance positive electrode active materials. A lithium-rich oxide (Li-rich layered oxide), a type of a positive electrode active material, is a mixed phase of a Li2MnO3 phase and a LiMO2 (where M is an element including Ni, Mn, Co or a combination thereof) phase, and has the characteristic of providing a very large capacity of 250 mAh/g at high operating voltages (>3.5 V vs. Li/Li+). Therefore, the lithium-rich oxide is attracting attention as a high-capacity positive electrode active material. However, the lithium-rich oxide has problems that occur due to the structural characteristic of having two phases mixed. Specifically, if a battery including the lithium-rich oxide is operated under high voltages, there is a problem in that irreversible capacity loss occurs in the first activation (first formation) process, resulting in reduced efficiency, and during the charge/discharge cycle, voltage fading occurs as a layered structure changes to a spinel structure and then to a rock salt structure, resulting in a problem such as the generation of O2 gas. In addition, the increasing price of cobalt raw materials included in the lithium-rich oxide is also emerging as a significant issue. The price of the cobalt raw material is expected to continue to increase, and accordingly, the development of positive electrode active materials with reduced cobalt content is required. Therefore, it is necessary to secure technology to improve the stability, performance, and economic efficiency of the lithium-rich oxide. [Prior Art Document] [Patent Document] (Patent Document 1) Korean Laid-open Patent Publication No. 10-2014-0025102 DISCLOSURE OF THE INVENTION TECHNICAL PROBLEM The present invention is intended to solve the above problems, and to provide a positive electrode active material, which may improve the capacity characteristics, efficiency characteristics, and output characteristics of a battery and reduce costs, and a method for preparing the same. In addition, the present invention is intended to provide an economical positive electrode and secondary battery, which has excellent capacity characteristics, efficiency characteristics, and output characteristics by including the positive electrode active material. TECHNICAL SOLUTION (1) The present invention provides a positive electrode active material comprising a lithium-rich manganese-based oxide comprising a Li2MnO3 phase and a LiMO2 (where M is an element comprising Ni, Mn or a combination thereof) phase at the same time, wherein the lithium-rich manganese-based oxide has a composition represented by Formula 1 below.         [Formula 1]     Li1+xNiaMnbWcM1dO2 In Formula 1, M1 is one or more selected from Al, P, V, Y, Ti and Nb,0.10≤x≤0.20, 0<a<0.5, 0.5≤b<1.0, 0<c<0.008, and 0≤d<0.005.(2) The present invention provides the positive electrode active material according to (1), wherein a is 0.30 to 0.35.(3) The present invention provides the positive electrode active material according to (1) or (2), wherein b is 0.55 to 0.60.(4) The present invention provides the positive electrode active material according to any one of (1) to (3), wherein c is 0.0005 to 0.007.(5) The present invention provides the positive electrode active material according to any one of (1) to (4), wherein the content of W is 800 ppm to 15,000 ppm on the basis of a total weight of the lithium-rich manganese-based oxide.(6) The present invention provides the positive electrode active material according to any one of (1) to (5), wherein the lithium-rich manganese-based oxide has a tap density of 1.5 g/cm3 to 2.5 g/cm3.(7) The present invention provides the positive electrode active material according to any one of (1) to (6), wherein the lithium-rich manganese-based oxide has an average particle diameter (D50) of 2 µm to 12 µm.(8) The present invention provides a method for preparing the positive electrode active material according to any one of (1) to (7),