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KR-20260063798-A - METHOD OF MANUFACTURING CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY

KR20260063798AKR 20260063798 AKR20260063798 AKR 20260063798AKR-20260063798-A

Abstract

The present invention relates to a method for manufacturing a positive electrode active material for a lithium secondary battery and a lithium secondary battery. The method for manufacturing a positive electrode active material for a lithium secondary battery comprises the steps of: mixing a precursor containing a transition metal, a lithium raw material, and a doping raw material to prepare a mixture; and calcining the mixture to form a lithium metal oxide. The doping raw material satisfies Formula 1 below. <Equation 1> 5 ≤ BET/(D max -D 50 )[m 2 /(g·㎛)] ≤ 14.8 (In Equation 1 above, BET represents the BET (Brunauer-Emmett-Teller) specific surface area ( m² /g) of the doping raw material, and D max and D 50 represent the maximum value and the particle size (μm) at the 50% point, respectively, in the cumulative volume distribution according to the particle size of the doping raw material.)

Inventors

  • 이수진
  • 김성인
  • 박혜정
  • 서성화
  • 박정현
  • 신동기

Assignees

  • (주)포스코퓨처엠

Dates

Publication Date
20260507
Application Date
20241031

Claims (11)

  1. A step of preparing a mixture by mixing a precursor containing a transition metal, a lithium raw material, and a doping raw material; and The method includes the step of calcining the above mixture to form a lithium metal oxide, The above doping raw material is a method for manufacturing a positive electrode active material for a lithium secondary battery satisfying Formula 1 below. <Equation 1> 5 ≤ BET/(D max -D 50 )[m 2 /(g·㎛)] ≤ 14.8 (In Equation 1 above, BET represents the BET (Brunauer-Emmett-Teller) specific surface area ( m² /g) of the doping raw material, and D max and D 50 represent the maximum value and the particle size (μm) at the 50% point, respectively, in the cumulative volume distribution according to the particle size of the doping raw material.)
  2. In Article 1, The above doping raw material is a method for manufacturing a positive electrode active material for a lithium secondary battery containing an yttrium-containing material.
  3. In Article 2, A method for manufacturing a positive electrode active material for a lithium secondary battery , wherein the above yttrium-containing material is one or more selected from YCl3 , Y2O3 , Y( NO3 ) 3 , Y(OH) 3 , YSZ, Y2 ( SO4 ) 3 , and Y2S3 .
  4. In Article 1, The above doping raw material is a method for manufacturing a positive electrode active material for a lithium secondary battery satisfying Formula 2 below. <Equation 2> 9.0 ≤ BET/D max [m 2 /(g·㎛)] (In Equation 2 above, BET represents the BET (Brunauer-Emmett-Teller) specific surface area ( m² /g) of the doping raw material, and Dmax represents the particle size (μm) of the maximum value in the cumulative volume distribution according to the particle size of the doping raw material.)
  5. In Article 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the BET specific surface area of the doping raw material is 12 to 20 m² /g.
  6. In Article 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the D max of the doping raw material is 0.8 to 1.3 μm.
  7. In Article 1, A method for manufacturing a positive electrode active material for a lithium secondary battery, wherein the D 50 of the above-mentioned doping raw material is 0.10 to 0.38 μm.
  8. In Article 1, After the step of calcining the above mixture to form lithium metal oxide, A method for manufacturing a positive electrode active material for a lithium secondary battery, comprising the step of dissolving the above lithium metal oxide.
  9. In Article 1, A method for manufacturing a positive electrode active material for a lithium secondary battery in which the above lithium metal oxide is in the form of a single particle.
  10. In Article 1, The above lithium metal oxide is a method for manufacturing a positive electrode active material for a lithium secondary battery satisfying the following chemical formula 1. <Chemical Formula 1> Li a [Ni x Co y Mn z Y w ]O 2 (In the above Chemical Formula 1, 0.9≤a≤1.1, 0.3≤x≤0.73, 0≤y≤0.3, 0≤z≤0.4, 0<w≤0.2, and x+y+z+w=1)
  11. A lithium secondary battery comprising a positive active material manufactured according to any one of claims 1 to 10.

Description

Method of manufacturing cathode active material for lithium secondary battery and lithium secondary battery The present invention relates to a method for manufacturing a positive electrode active material for a lithium secondary battery and to a lithium secondary battery. Lithium cobalt oxide ( LiCoO2 ), lithium nickel oxide ( LiNiO2 ), lithium manganese oxide ( LiMnO2 or LiMnO4, etc.), and lithium iron phosphate compounds ( LiFePO4 ) have been used as cathode active materials for lithium secondary batteries. Among these, lithium cobalt oxide has the advantages of high operating voltage and excellent capacity characteristics; however, it is difficult to apply it commercially to high-capacity batteries due to the high cost and unstable supply of cobalt, which is the raw material. Lithium nickel oxide has poor structural stability, making it difficult to achieve sufficient lifespan characteristics. Meanwhile, lithium manganese oxide has excellent stability but has the problem of poor capacity characteristics. Accordingly, lithium composite transition metal oxides containing two or more transition metals have been developed to compensate for the problems of lithium transition metal oxides containing Ni, Co, or Mn alone. Among these, lithium nickel cobalt manganese oxide containing Ni, Co, and Mn is widely used in the field of electric vehicle batteries. Conventional lithium nickel cobalt manganese oxide was generally in the form of spherical secondary particles formed by the aggregation of tens to hundreds of primary particles. However, in the case of lithium nickel cobalt manganese oxide in the form of secondary particles, there are problems such as particle breakage where primary particles detach during the rolling process in cathode manufacturing, and cracks occurring inside the particles during the charging and discharging process. If particle breakage or cracking occurs in the cathode active material, the contact area with the electrolyte increases, leading to increased gas generation and active material degradation due to side reactions with the electrolyte, which in turn reduces lifespan characteristics. Furthermore, with the recent increase in demand for high-output, high-capacity batteries, such as those for electric vehicles, there is a trend toward gradually increasing the nickel content in cathode active materials (so-called "high-nickel"). While increasing the nickel content in cathode active materials improves initial capacity characteristics, repeated charging and discharging generates a large amount of highly reactive Ni +4 ions, leading to structural breakdown of the cathode active material. This accelerates the degradation rate of the material, resulting in reduced lifespan characteristics and decreased battery safety. To solve the above problem, a technology has been proposed to manufacture a cathode active material in the form of a single particle rather than a secondary particle by increasing the calcination temperature during the production of lithium nickel cobalt manganese oxide. In the case of a cathode active material in the form of a single particle, the contact area with the electrolyte is smaller compared to conventional cathode active materials in the form of secondary particles, so there are fewer side reactions with the electrolyte, and the particle strength is excellent, resulting in less particle breakage during electrode manufacturing. Therefore, when a cathode active material in the form of a single particle is applied, there are advantages such as reduced gas generation and excellent lifespan characteristics. However, due to the rising prices of raw materials for nickel and cobalt, and the thermal propagation issues that arise when nickel accounts for an excessively high content, the development of raw materials other than nickel, particularly doping raw materials, is being actively pursued. FIGS. 1 to 5 are Scanning Electron Microscopy (SEM) images of a positive electrode active material according to an embodiment and a comparative example 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