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CN-121986072-A - Method for preparing positive electrode active material for lithium secondary battery, and lithium secondary battery comprising same

CN121986072ACN 121986072 ACN121986072 ACN 121986072ACN-121986072-A

Abstract

The present invention relates to a method for preparing a positive electrode active material for a lithium secondary battery, comprising a step of preparing a manganese-rich transition metal precursor having a molar ratio (Mn/M) of manganese (Mn) to transition metal (M) of 0.5 to 0.75, a step of oxidizing (oxidation) the transition metal precursor by primary calcination, and a step of lithiating (lithiation) the oxidized transition metal precursor by secondary calcination to form a lithium and manganese-rich lithium transition metal oxide.

Inventors

  • ZHENG QIRONG
  • Pu Yunche
  • Pu Yinche
  • YU BINGLONG
  • Cui Genhao
  • Liang Zhongmo
  • Huang Chunche

Assignees

  • 浦项控股股份有限公司
  • 浦项产业科学硏究院

Dates

Publication Date
20260505
Application Date
20241011
Priority Date
20231011

Claims (17)

  1. 1. A method for preparing a positive active material of a lithium secondary battery, comprising: A step of preparing a manganese-rich transition metal precursor having a molar ratio (Mn/M) of manganese (Mn) to transition metal (M) of 0.5 to 0.75; a step of oxidizing the transition metal precursor by one-time calcination, and And a step of subjecting the oxidized transition metal precursor to secondary calcination to lithiate it to form a lithium and manganese-rich lithium transition metal oxide.
  2. 2. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The lithium starting material is introduced at the primary calcination or at the secondary calcination.
  3. 3. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The secondary calcination temperature is higher than the primary calcination temperature, and the difference between the secondary calcination temperature and the primary calcination temperature is 550 ℃ or more.
  4. 4. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The primary calcination temperature is 150 to 300 ℃.
  5. 5. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The primary calcination time is 0.5 to 5 hours.
  6. 6. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The secondary calcination temperature is 800 to 900 ℃.
  7. 7. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The secondary calcination time is 1 to 12 hours.
  8. 8. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The molar ratio (Ni/M) of nickel (Ni) to transition metal (M) in the transition metal precursor is 0.2 to 0.4.
  9. 9. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The molar ratio (Co/M) of cobalt (Co) to transition metal (M) in the transition metal precursor is 0.2 or less.
  10. 10. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 2, wherein, The molar ratio (Li/M) of lithium (Li) to transition metal (M) of the lithium raw material is 1.1 or more.
  11. 11. The method for preparing a positive electrode active material for a lithium secondary battery according to claim 1, wherein, The lithium transition metal oxide is represented by the following chemical formula 1, [ Chemical formula 1] Li 1+a (Ni x Co y Mn z M w ) 1-a O 2 In the chemical formula 1, 0.1≤a≤ 0.3,0.2≤x≤0.4, 0≤y≤0.2, 0.5≤z≤ 0.75,0≤w≤0.2, x+y+z+w=1, and m is Zr, al, B, Y, mg, ti, nb, W, sc, si, V, fe, Y, mo, ce, hf, ta, la, sr, sn, sb, zn, cu, ge, mo, ru, ir or a combination thereof.
  12. 12. A positive electrode active material for a lithium secondary battery, wherein, The positive electrode active material contains lithium and manganese-rich lithium transition metal oxides in which oxidation and lithiation of the core portion and the surface portion uniformly occur, The lithium transition metal oxide is a lithium to lithium transition metal oxide having a molar ratio of 1.1 to 1.3, a manganese to transition metal molar ratio of 0.5 to 0.75, The average grain size is 40 to 50nm.
  13. 13. The positive electrode active material for a lithium secondary battery according to claim 12, wherein, The lithium transition metal oxide has a BET specific surface area of 2.5m 2 /g or more.
  14. 14. The positive electrode active material for a lithium secondary battery according to claim 12, wherein, The lithium transition metal oxide satisfies the following formula 1, [ 1] BET/D50≥0.4m 2 /g·μm In the above formula 1, BET is the BET specific surface area (m 2 /g) of the lithium transition metal oxide, and D50 is the average particle diameter (D50) of the lithium transition metal oxide.
  15. 15. The positive electrode active material for a lithium secondary battery according to claim 12, wherein, The lithium transition metal oxide is represented by the following chemical formula 1, [ Chemical formula 1] Li 1+a (Ni x Co y Mn z M w ) 1-a O 2 In the chemical formula 1, 0.1≤a≤ 0.3,0.2≤x≤0.4, 0≤y≤0.2, 0.5≤z≤ 0.75,0≤w≤0.2, x+y+z+w=1, and m is Zr, al, B, Y, mg, ti, nb, W, sc, si, V, fe, Y, mo, ce, hf, ta, la, sr, sn, sb, zn, cu, ge, mo, ru, ir or a combination thereof.
  16. 16. A positive electrode for a lithium secondary battery comprising the positive electrode active material according to any one of claims 12 to 15.
  17. 17. A lithium secondary battery comprising the positive electrode of the lithium secondary battery of claim 16.

Description

Method for preparing positive electrode active material for lithium secondary battery, and lithium secondary battery comprising same Technical Field The present invention relates to a method for preparing a positive electrode active material for a lithium secondary battery, and a lithium secondary battery comprising the same. Background The electric automobile market using lithium secondary batteries is greatly expanding. Currently, a ternary layered compound (NCM system or NCA system) is used as a positive electrode active material for lithium secondary batteries for electric vehicles, and the energy density is continuously increased by increasing the nickel content. However, ternary layered compounds have limitations in meeting the continuing demands of the market such as further cost reduction, further energy density improvement, and sustainable use of materials. Therefore, lithium-rich layered cathode active materials (OLO: over-LITHIATED OXIDE or LLO: li-RICH LAYERED Oxide) having a low nickel content and capable of achieving a high capacity through anionic oxidation/reduction are receiving attention again. Disclosure of Invention Technical problem to be solved In one aspect, the present invention is directed to a method of preparing a positive electrode active material, which is a lithium transition metal oxide of a lithium manganese-rich component, having overall improved capacity, initial efficiency, and output characteristics, a positive electrode active material, and a secondary battery including the same. Technical proposal An embodiment of the present invention provides a method for preparing a positive electrode active material for a lithium secondary battery, comprising a step of preparing a manganese-rich transition metal precursor having a molar ratio (Mn/M) of manganese (Mn) to transition metal (M) of 0.5 to 0.75, a step of oxidizing (oxidation) the transition metal precursor by primary calcination, and a step of lithiating (lithiation) the oxidized transition metal precursor by secondary calcination to form a lithium and manganese-rich lithium transition metal oxide. The lithium starting material may be introduced at the primary calcination or at the secondary calcination. The secondary calcination temperature may be higher than the primary calcination temperature, and a difference between the secondary calcination temperature and the primary calcination temperature may be 550 ℃ or more. The primary calcination temperature may be 150 to 300 ℃. The primary calcination time may be 0.5 to 5 hours. The secondary calcination temperature may be 800 to 900 ℃. The secondary calcination time may be 1 to 12 hours. The molar ratio of nickel (Ni) to transition metal (M) in the transition metal precursor (Ni/M) may be 0.2 to 0.4. The molar ratio of cobalt (Co) to transition metal (M) in the transition metal precursor (Co/M) may be 0.2 or less. The lithium raw material may be introduced to a molar ratio (Li/M) of lithium (Li) to transition metal (M) of 1.1 or more. The lithium transition metal oxide may be represented by the following chemical formula 1. [ Chemical formula 1] Li1+a(NixCoyMnzMw)1-aO2 In the chemical formula 1, 0.1≤a≤ 0.3,0.2≤x≤0.4, 0≤y≤0.2, 0.5≤z≤ 0.75,0≤w≤0.2, x+y+z+w=1, and m is Zr, al, B, Y, mg, ti, nb, W, sc, si, V, fe, Y, mo, ce, hf, ta, la, sr, sn, sb, zn, cu, ge, mo, ru, ir or a combination thereof. Another embodiment of the present invention provides a lithium secondary battery positive electrode active material including lithium and manganese-rich lithium transition metal oxide in which oxidation (lithiation) and lithiation (lithiation) of a core portion and a surface portion uniformly occur, the lithium transition metal oxide being a molar ratio of lithium to lithium transition metal oxide of 1.1 to 1.3, a molar ratio of manganese to transition metal of 0.5 to 0.75, and an average grain size (CRYSTALLITE SIZE) of 40 to 50nm. The lithium transition metal oxide may have a BET specific surface area of 2.5m 2/g or more. The lithium transition metal oxide may satisfy the following formula 1. [ 1] BET/D50≥0.4m2/g·μm In the above formula 1, BET is the BET specific surface area (m 2/g) of the lithium transition metal oxide, and D50 is the average particle diameter (D50) of the lithium transition metal oxide. The lithium transition metal oxide may be represented by the following chemical formula 1. [ Chemical formula 1] Li1+a(NixCoyMnzMw)1-aO2 In the chemical formula 1, 0.1≤a≤ 0.3,0.2≤x≤0.4, 0≤y≤0.2, 0.5≤z≤ 0.75,0≤w≤0.2, x+y+z+w=1, and m is Zr, al, B, Y, mg, ti, nb, W, sc, si, V, fe, Y, mo, ce, hf, ta, la, sr, sn, sb, zn, cu, ge, mo, ru, ir or a combination thereof. Yet another embodiment of the present invention provides a lithium secondary battery positive electrode comprising the aforementioned positive electrode active material. Yet another embodiment of the present invention provides a lithium secondary battery including the positive electrode of the lithium secondary battery. Adva