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CN-115692699-B - Positive electrode active material of all-solid-state battery, method for preparing same, and all-solid-state battery

CN115692699BCN 115692699 BCN115692699 BCN 115692699BCN-115692699-B

Abstract

Disclosed are a positive electrode active material for an all-solid battery, a method for preparing the same, and an all-solid battery. The positive electrode active material includes secondary particles in which a plurality of primary particles are aggregated, wherein at least a portion of the primary particles are radially arranged, and includes a first boron coating portion on the surface of the secondary particles, and a second boron coating portion on the surface of the primary particles in an inner portion of the secondary particles.

Inventors

  • Yin Bixiang
  • Jin Xuanfan
  • Pu Shangren
  • XU GUANGZHONG
  • Liu rongzan

Assignees

  • 三星SDI株式会社

Dates

Publication Date
20260508
Application Date
20211124
Priority Date
20210723

Claims (20)

  1. 1. A positive electrode active material for an all-solid battery, comprising a lithium nickel-based composite oxide, and comprising: Wherein secondary particles of a plurality of primary particles are aggregated, wherein at least a portion of the primary particles are radially arranged, A first boron coating portion on the surface of the secondary particles, and A second boron coating portion on the surface of the primary particles in the inner portion of the secondary particles.
  2. 2. The positive electrode active material according to claim 1, wherein each of the first boron coating portion and the second boron coating portion comprises a boron oxide, a lithium boron oxide, or a combination thereof.
  3. 3. The positive electrode active material according to claim 1, wherein a weight of the first boron coating portion is greater than a weight of the second boron coating portion.
  4. 4. The positive electrode active material according to claim 1, wherein the first boron coating portion is included in an amount of 70wt% to 98wt%, and the second boron coating portion is included in an amount of 2wt% to 30wt%, based on the total amount of the first boron coating portion and the second boron coating portion.
  5. 5. The positive electrode active material according to claim 1, wherein the content of the first boron coating portion is 0.02wt% to 0.3wt%, based on the total weight of the positive electrode active material.
  6. 6. The positive electrode active material according to claim 1, wherein the content of the second boron coating portion may be 0.001wt% to 0.05wt%, based on the total weight of the positive electrode active material.
  7. 7. The cathode active material according to claim 1, wherein a total amount of the first boron coating portion and the second boron coating portion is 0.1mol% to 3mol%, based on 100mol% of the cathode active material.
  8. 8. The positive electrode active material according to claim 7, wherein a total amount of the first boron coating portion and the second boron coating portion is 0.1mol% to 1.5mol% based on 100mol% of the positive electrode active material.
  9. 9. The positive electrode active material according to claim 1, wherein the primary particles have a plate shape, and at least a part of the plate-shaped primary particles have long axes aligned in a radial direction.
  10. 10. The positive electrode active material according to claim 9, wherein an average length of the plate-shaped primary particles is 150nm to 500nm, an average thickness of the plate-shaped primary particles is 100nm to 200nm, and a ratio of the average thickness to the average length is 1:2 to 1:5.
  11. 11. The positive electrode active material according to claim 1, wherein the secondary particles comprise an inner portion comprising an irregular porous structure and an outer portion comprising a radially aligned structure.
  12. 12. The positive electrode active material according to claim 11, wherein The inner portion of the secondary particles has a larger pore size than the outer portion, The pore size in the inner portion of the secondary particles is 150nm to 1 μm, and The pore size in the outer portion of the secondary particles is less than 150nm.
  13. 13. The positive electrode active material according to claim 1, wherein the secondary particles include openings having a size of less than 150nm and a depth of less than or equal to 150nm on a surface facing a center of the inner portion.
  14. 14. The positive electrode active material according to claim 1, wherein the lithium nickel-based composite oxide is represented by chemical formula 1: [ chemical formula 1] Li a1 Ni x1 M 1 y1 M 2 1-x1-y1 O 2 Wherein, in chemical formula 1, 0.9≤a1≤ 1.8,0.3≤x1≤1, 0≤y1≤0.7, and M 1 and M 2 are each independently selected from Al, B, ba, ca, ce, co, cr, cu, F, fe, mg, mn, mo, nb, P, S, si, sr, ti, V, W, zr and combinations thereof.
  15. 15. A method of preparing a positive electrode active material for an all-solid battery, comprising: mixing lithium raw material, nickel hydroxide and boron raw material, and Heat-treating the resultant to obtain the positive electrode active material according to any one of claims 1 to 14.
  16. 16. The method according to claim 15, wherein the boron raw material is contained in an amount of 0.1mol% to 3mol%, based on 100mol% of the nickel-based hydroxide.
  17. 17. The method of claim 15, wherein the heat treatment is performed at a temperature of 650 ℃ to 850 ℃ for 5 hours to 20 hours.
  18. 18. An all-solid battery comprising: a positive electrode comprising the positive electrode active material according to any one of claims 1 to 14, a negative electrode, and a solid electrolyte layer between the positive electrode and the negative electrode.
  19. 19. The all-solid battery according to claim 18, wherein The positive electrode includes a current collector and a positive electrode active material layer on the current collector, the positive electrode active material layer including the positive electrode active material and a solid electrolyte, and The solid electrolyte is included in an amount of 0.1wt% to 35wt% based on the total weight of the positive electrode active material layer.
  20. 20. The all-solid battery according to claim 18, wherein the negative electrode includes a current collector and a negative electrode active material layer or a negative electrode catalyst layer provided on the current collector.

Description

Positive electrode active material of all-solid-state battery, method for preparing same, and all-solid-state battery Technical Field Disclosed are a positive electrode active material for an all-solid battery, a method for preparing the same, and an all-solid battery. Background Portable information devices such as cellular phones, laptop computers, smart phones, and the like, or electric automobiles have used rechargeable lithium batteries having high energy density and easy portability as driving power sources. Recently, research has been actively conducted to use a rechargeable lithium battery having a high energy density as a driving power source or an electric storage power source for a hybrid car or an electric car. All-solid-state batteries among rechargeable lithium batteries refer to batteries in which all materials are solid, and in particular batteries using solid electrolytes. The all-solid battery is safe, free from the risk of explosion due to leakage of electrolyte and also easy to manufacture into a thin battery. Recently, various positive electrode active materials applicable to the all-solid battery are being studied. The conventionally used lithium nickel oxide, lithium nickel manganese cobalt composite oxide, lithium nickel cobalt aluminum composite oxide, lithium cobalt oxide, and the like have been mainly studied, but there is a limit in achieving satisfactory performance of the all-solid battery. Accordingly, development of a new positive electrode active material is required to achieve all-solid-state batteries that ensure long-term cycle life characteristics and achieve high capacity and high energy density. Disclosure of Invention Provided are a positive electrode active material for an all-solid battery having improved cycle life characteristics while achieving high capacity, a method of preparing the same, and an all-solid battery including the same. In an embodiment, a positive electrode active material for an all-solid battery includes a lithium nickel-based composite oxide, wherein the positive electrode active material includes secondary particles in which a plurality of primary particles are aggregated, wherein at least a portion of the primary particles are radially arranged, a first boron coating portion on a surface of the secondary particles, and a second boron coating portion on a surface of the primary particles in an inner portion of the secondary particles. Each of the first boron coating portion and the second boron coating portion may include boron oxide, lithium boron oxide, or a combination thereof. The weight of the first boron coating portion may be greater than the weight of the second boron coating portion. The first boron coating portion may be included in an amount of about 70wt% to about 98wt% and the second boron coating portion may be included in an amount of about 2wt% to about 30wt% based on the total amount of the first boron coating portion and the second boron coating portion. The first boron coating portion may be present in an amount of about 0.02wt% to about 0.3wt% based on the total weight of the positive electrode active material. The second boron coating portion may be present in an amount of about 0.001wt% to about 0.05wt% based on the total weight of the positive electrode active material. The total amount of the first boron coating portion and the second boron coating portion may be about 0.1mol% to about 3mol% or about 0.1mol% to about 1.5mol% based on 100mol% of the positive electrode active material. The primary particles may have a plate shape, and at least a portion of the plate-shaped primary particles may have long axes aligned in a radial direction. The average length of the plate-like primary particles may be about 150nm to about 500nm, the average thickness of the plate-like primary particles may be about 100nm to about 200nm, and the ratio of the average thickness to the average length may be about 1:2 to about 1:5. The secondary particles may include an inner portion comprising an irregular porous structure and an outer portion comprising a radially aligned structure. The inner portion of the secondary particle may have a larger pore size than the outer portion, the pore size in the inner portion of the secondary particle may be from about 150nm to about 1 μm, and the pore size in the outer portion of the secondary particle may be less than about 150nm. The secondary particles may include openings having a size of less than about 150nm on a surface facing the center of the inner portion. The lithium nickel-based composite oxide may be represented by chemical formula 1. [ Chemical formula 1] Lia1Nix1M1y1M21-x1-y1O2 In chemical formula 1, 0.9≤a1≤ 1.8,0.3≤x1≤1, 0≤y1≤0.7, M 1 and M 2 are each independently selected from Al, B, ba, ca, ce, co, cr, cu, F, fe, mg, mn, mo, nb, P, S, si, sr, ti, V, W, zr and combinations thereof. In another embodiment, a method of preparing a positive electrode active material for an all-solid battery i