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KR-102963861-B1 - Precursor, preparation method thereof, and cathode active material for lithium secondary battery

KR102963861B1KR 102963861 B1KR102963861 B1KR 102963861B1KR-102963861-B1

Abstract

The present invention relates to a precursor, a method for manufacturing the same, and a positive electrode active material for a lithium secondary battery comprising the same; more specifically, it relates to an oxidation precursor using an oxidizing agent, a method for manufacturing the same, and a positive electrode active material for a lithium secondary battery comprising the same.

Inventors

  • 정광은
  • 최승언
  • 이창현
  • 남경원
  • 정도각
  • 박준영

Assignees

  • (주)포스코퓨처엠

Dates

Publication Date
20260511
Application Date
20230920

Claims (19)

  1. A core portion represented by Chemical Formula 1; and A surface portion represented by Chemical Formula 2; comprising, The ratio of the Ni oxidation water of the surface portion to the Ni oxidation water of the core portion is 1 to 2, and The above precursor is a precursor having a specific surface area of 13 to 18 m² /g as measured by the nitrogen adsorption BET method: [Chemical Formula 1] Ni a Co b Mn c (OH) 2 (In the above Chemical Formula 1, 0.6≤a≤0.9, 0≤b≤0.2, 0≤c≤0.2, and a+b+c=1.) [Chemical Formula 2] Ni x Co y Mn z (OOH) (In Chemical Formula 2 above, 0.6≤x≤0.9, 0≤y≤0.2, 0≤z≤0.2, and x+y+z=1.)
  2. delete
  3. delete
  4. In paragraph 1, A precursor having a specific surface area of 1.2 to 1.6 m² /gπm relative to the average particle size (D 50 ) of the above precursor.
  5. In paragraph 1, The precursor has an average particle size (D 50 ) of 9 to 11 μm.
  6. In paragraph 1, The above precursor is a precursor having an agglomerated structure composed of aggregates of microparticles.
  7. It is a layered active material in the form of secondary particles composed of primary particles, and The above active material includes a core portion and a surface portion, and The ratio of the Ni oxidation water of the surface portion to the Ni oxidation water of the core portion is 1 to 2, and The specific surface area (BET) of the above positive active material is 0.25 to 0.32 m² /g, and A positive active material having a press density of 1.97 to 2.05 g/ cm³ .
  8. In Paragraph 7, A positive active material having an average particle size (D 50 ) of 9.8 to 11 μm.
  9. delete
  10. In Paragraph 7, A positive active material having a specific surface area of 0.02 to 0.04 m² /gπm relative to the average particle size (D 50 ) of the positive active material.
  11. delete
  12. In Paragraph 7, A positive active material having a resistance of 15.5 to 16.2 Ω.
  13. A positive active material manufactured using a precursor according to any one of paragraphs 1 and 4 through 6: [Chemical Formula 1] Ni a Co b Mn c (OH) 2 (In the above Chemical Formula 1, 0.6≤a≤0.9, 0≤b≤0.2, 0≤c≤0.2, and a+b+c=1.) [Chemical Formula 2] Ni x Co y Mn z (OOH) (In Chemical Formula 2 above, 0.6≤x≤0.9, 0≤y≤0.2, 0≤z≤0.2, and x+y+z=1.)
  14. Step of preparing a precursor; and The method includes a step of oxidizing the above precursor, and The above-mentioned manufactured precursor is, A precursor comprising a core portion represented by Chemical Formula 1; and a surface portion represented by Chemical Formula 2; and The above oxidation step involves using an oxidizing agent to oxidize only the surface portion of the precursor, and A method for manufacturing a precursor, wherein the molar ratio of the precursor to the oxidizing agent is 0.3 to 0.7: [Chemical Formula 1] Ni a Co b Mn c (OH) 2 (In Chemical Formula 1 above, 0.6≤a≤0.9, 0≤b≤0.2, 0≤c≤0.2, and a+b+c=1.) [Chemical Formula 2] Ni x Co y Mn z (OOH) (In Chemical Formula 2 above, 0.6≤x≤0.9, 0≤y≤0.2, 0≤z≤0.2, and x+y+z=1.)
  15. delete
  16. In Paragraph 14, A method for preparing a precursor, wherein the oxidizing agent comprises one or more oxidizing agents selected from sodium persulfate, ammonium persulfate, potassium persulfate, sodium peroxomonosulfate, potassium peroxymonosulfate, hydrogen peroxide, benzoyl peroxide, sodium peroxide, calcium peroxide, and barium peroxide.
  17. delete
  18. In Paragraph 14, A method for manufacturing a precursor, wherein the reaction temperature during the manufacture of the above precursor is in the range of 40 to 60℃.
  19. In Paragraph 14, A method for manufacturing a precursor, wherein the reaction time during the preparation of the above precursor is in the range of 30 to 45 hours.

Description

Precursor, preparation method thereof, and cathode active material for lithium secondary battery containing the same The present invention relates to a precursor, a method for manufacturing the same, and a positive electrode active material for a lithium secondary battery comprising the same. More specifically, the invention relates to a precursor in which only the surface of the precursor is oxidized using an oxidizing agent, a method for manufacturing the same, and a positive electrode active material for a lithium secondary battery comprising the same. Lithium-ion batteries are widely used in electric vehicles, energy storage devices, and small portable devices due to their high energy density and excellent charge/discharge performance. With the recent miniaturization of electronic devices, there is a need for high-capacity rechargeable batteries; in particular, there is a demand for the development of lithium-ion batteries, which have a higher energy density compared to nickel-hydrogen and nickel-cadmium batteries. Lithium cobalt oxide ( LiCoO2 ), lithium nickel oxide ( LiNiO2 ), lithium manganese oxide ( LiMnO2 or LiMn2O4 , etc. ), and lithium iron phosphate compounds ( LiFePO4 ) are used as cathode active materials for lithium secondary batteries. Among these, lithium cobalt oxide ( LiCoO2 ) is widely used and applied as a cathode active material for high voltage applications due to its advantages of high operating voltage and excellent capacity characteristics. However, due to the rising price and supply instability of cobalt (Co), there are limitations to its mass use as a power source in fields such as electric vehicles, leading to the need for the development of cathode active materials that can replace it. Accordingly, a nickel-cobalt-manganese-based lithium composite metal oxide (hereinafter simply referred to as "NCM-based lithium composite metal oxide") in which a portion of the cobalt is substituted with nickel and manganese has been developed. An oxidation precursor is prepared by introducing oxygen gas instead of an inert gas during the co-precipitation reaction using the lithium composite metal oxide, or by heat-treating the precursor in an oxygen atmosphere. However, the oxidation precursor prepared by the above method has the problem that the interior of the precursor is also oxidized, and when oxidation is performed by heat-treating in an oxygen atmosphere, there is an issue of additional costs incurred for heat treatment using a calcination furnace. Therefore, there is an urgent need to develop precursors capable of improving precursor instability and enhancing productivity and economic efficiency by controlling the degree of oxidation on the precursor surface, as well as cathode active materials containing such precursors. Figure 1 is a scanning electron microscope (SEM) image of a positive electrode active material according to Example 2 of the present invention. Figure 2 is a scanning electron microscope (SEM) image of a positive electrode active material according to Comparative Example 2 of the present invention. Figure 3 is a scanning electron microscope (SEM) image of a precursor according to Comparative Example 1 of the present invention. Figure 4 is a scanning electron microscope (SEM) image of an oxidation precursor according to Example 1 of the present invention. Terms such as first, second, and third are used to describe various parts, components, regions, layers, and/or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, 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. The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and/or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and/or components. When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the pre