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KR-102963864-B1 - MANUFACTURING METHOD FOR CATHODE ACTIVE MATERIAL, CATHODE ACTIVE MATERIAL AND LITHIUM ION BATTERY MANUFACTURED USING THE SAME

KR102963864B1KR 102963864 B1KR102963864 B1KR 102963864B1KR-102963864-B1

Abstract

A method for manufacturing a positive electrode active material for a lithium secondary battery according to the present invention comprises the steps of: preparing a nickel-containing metal hydroxide precursor; forming a mixture comprising the nickel-containing metal hydroxide precursor and a lithium raw material containing Li₂O₂ , and then performing a first calcination and a second calcination in a 1-step process to obtain a calcined product; and crushing the calcined product to obtain a metal oxide in the form of a single particle; wherein the second calcination is performed at a lower temperature than the first calcination.

Inventors

  • 김성인
  • 이의태
  • 이수진
  • 권택기
  • 박정현
  • 김재한
  • 최권영

Assignees

  • (주)포스코퓨처엠

Dates

Publication Date
20260511
Application Date
20230627

Claims (20)

  1. Step of preparing a nickel-containing metal hydroxide precursor; A step of forming a mixture comprising the nickel-containing metal hydroxide precursor and a lithium raw material containing Li₂O₂ , and then obtaining a calcined product by performing a first calcination and a second calcination in a 1-step process; and The method comprises the step of crushing the above-mentioned calcined product to obtain a metal oxide in the form of a single particle; The above secondary firing is performed at a lower temperature than the above primary firing, and The method further comprises the step of mixing the obtained metal oxide with a coating layer forming material and heat-treating it to form a coating layer. A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein, for the crystal of the metal oxide having a coating layer formed thereon, the ratio of the c-axis length to the a-axis length obtained by X-ray diffraction analysis (c/a) is 4.9320 to 4.9335.
  2. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the above-mentioned first calcination is performed at a temperature of 800 to 860°C.
  3. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the above secondary calcination is performed at a temperature of 740 to 780°C.
  4. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the above-mentioned first calcination is performed for 2 to 5 hours.
  5. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the above secondary calcination is performed for 7 to 11 hours.
  6. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the difference in calcination temperature between the first calcination and second calcination processes is 130℃ or less.
  7. In paragraph 6, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the difference in calcination temperature between the first calcination and second calcination processes is in the range of 50 to 90℃.
  8. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the above-mentioned disintegration process is performed by cooling the above-mentioned calcined material to 50 to 200°C.
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  11. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the cation mixing ratio of nickel cations in the lithium layer within the crystal structure of the obtained single-particle metal oxide is 2.0% or less.
  12. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the residual lithium is 0.35 weight% or less with respect to the entire metal oxide on which the coating layer is formed.
  13. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the compressive density of the metal oxide having a coating layer formed thereon is 2.303 g/cc or higher.
  14. In paragraph 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein 3g of a sample is placed into a mold with a diameter of 1.3cm and pressed with 6 tons, and the increase in the ratio of fine particles of 1㎛ or less before and after pressing is 1.62% or less.
  15. It is a metal oxide in the form of a single particle, and With respect to the entire single-particle metal oxide, the residual lithium is 0.35 weight% or less, and It further includes a coating layer located on the surface of the metal oxide in the form of a single particle, and A positive electrode active material for a lithium secondary battery, wherein the ratio of the c-axis length to the a-axis length (c/a) obtained by X-ray diffraction analysis for the crystal of the metal oxide on which the coating layer is formed is 4.9320 to 4.9335.
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  18. In paragraph 15, A positive electrode active material for a lithium secondary battery, wherein the cation mixing ratio of nickel cations in the lithium layer within the crystal structure of the metal oxide is 2.0% or less.
  19. In paragraph 15, A positive electrode active material for a lithium secondary battery having a compression density of 2.303 g/cc or higher.
  20. In paragraph 15, A positive electrode active material for a lithium secondary battery, wherein 3g of a sample is placed into a mold with a diameter of 1.3cm and pressed with 6 tons, and the increase in the ratio of fine particles of 1㎛ or less before and after pressing is 1.62% or less.

Description

Manufacturing method for cathode active material, cathode active material manufactured using the same, and lithium ion battery The present invention relates to a method for manufacturing a positive electrode active material, a positive electrode active material manufactured using the same, and a lithium secondary battery. Driven by the recent explosive demand for electric vehicles and the need for increased driving range, the development of high-capacity, high-energy-density secondary batteries to meet these demands is actively underway worldwide. To satisfy these requirements, a technology using high-nickel NCM (nickel-cobalt-manganese) cathode materials with a high Ni content has been proposed. In addition, to improve the electrode plate density of the cell components, bimodal forms in which large and small particles are blended in a certain fraction are being widely developed. However, in the case of cathode materials composed of secondary particles aggregated from primary particles ranging in size from tens of nanometers to several micrometers, the specific surface area of the powder is large, resulting in a large contact area with the electrolyte, which leads to a high possibility of gas generation and deterioration of lifespan characteristics. To solve these problems, methods have been proposed to increase the size of primary particles using sintering agents or flux. However, in this case, a rock salt structure is formed on the surface of the particles, which increases residual lithium and degrades the electrochemical performance of the cathode active material. Therefore, there is a need to develop a positive electrode active material that has excellent electrochemical performance while increasing the size of the primary particles. Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention, and the present invention is defined only by the scope of the claims set forth below. In the present invention, when it is stated that a certain member is located "on" another member, this includes not only cases where a certain member is in direct contact with another member, but also cases where another member is interposed between the two members. In the present invention, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Method for manufacturing a positive electrode active material for a lithium secondary battery One aspect of the present invention relates to a method for manufacturing a positive electrode active material for a lithium secondary battery, comprising the steps of: preparing a nickel-containing metal hydroxide precursor; forming a mixture comprising the nickel-containing metal hydroxide precursor and a lithium raw material containing Li₂O₂ , and then performing a first calcination and a second calcination in a 1-step process to obtain a calcined product; and disintegrating the calcined product to obtain a metal oxide in the form of a single particle; wherein the second calcination is performed at a lower temperature than the first calcination. The method for manufacturing a positive electrode active material for a lithium secondary battery according to the present invention hasthe advantage of being able to obtain a positive electrode active material with a high tap density, a low particle breakage rate, and a low residual lithium content compared to when other lithium raw materials such as LiOH· H₂O and Li₂CO₃ are used, because Li₂O₂ is used as a lithium raw material. Step of preparing a nickel-containing metal hydroxide precursor The above nickel-containing metal hydroxide may be purchased directly and used, or manufactured and used by conventional methods practiced in the industry. Step of obtaining a calcined product The method for manufacturing a positive electrode active material for a lithium secondary battery according to the present invention includes the step of forming a mixture comprising the nickel-containing metal hydroxide precursor and a lithium raw material containing Li₂O₂ , and then performing a first calcination and a second calcination in a 1-step process to obtain a calcined product. The method for manufacturing a positive electrode active material for a lithiumsecondary battery according to the present invention has the advantage of obtaining a positive electrode active material having a high tap density and a low particle breakage rate, and a low residual lithium content by using a lithium raw material containing Li₂O₂. In the case of commonly used LiOH· H₂O and Li₂CO₃ , they decompose during calcination, generating H₂O and CO₂ . When the above-mentioned lithium raw material and nickel-containing metal hydroxide precursor mixture is calcined, H₂O and CO₂ inhibit the forward reaction, which can increase the amount of lithiu