Positive electrode active material, method for preparing the same, positive electrode, and rechargeable lithium battery

Abstract

The present invention relates to a positive electrode active material, a method of preparing the same, a positive electrode, and a rechargeable lithium battery. The method for preparing the positive electrode active material can include: (i) adding an aluminum raw material and sodium hydroxide to an aqueous (e.g., water-soluble) solvent to prepare a coating solution having a pH range of 12.5 to 14; (ii) adding core particles including a lithium-nickel-based complex oxide to the coating solution to prepare a first mixed solution; (iii) adding a cobalt raw material to the first mixed solution to prepare a second mixed solution; and (iv) drying and heat-treating the second mixed solution to obtain the positive electrode active material.

Claims

1. A method for preparing a positive electrode active material, comprising: (i) Add aluminum feedstock and sodium hydroxide to an aqueous solvent to prepare a coating solution with a pH range of 12.5 to 14; (ii) Adding core particles to the coating solution to prepare a first mixed solution, the core particles comprising lithium nickel-based composite oxide; (iii) Add cobalt raw material to the first mixed solution to prepare a second mixed solution; and (iv) The second mixed solution is dried and heat-treated to obtain the positive electrode active material.

2. The method according to claim 1, wherein the aluminum content in the aluminum raw material is in the range of 0.1 mol% to 1.0 mol% based on a total of 100 mol% of metals other than lithium in the lithium-nickel-based composite oxide.

3. The method according to claim 1, wherein the sodium content in the sodium hydroxide is in the range of 2.0 mol% to 8.0 mol% based on a total of 100 mol% of metals other than lithium in the lithium-nickel-based composite oxide.

4. The method of claim 1, wherein the pH of the first mixed solution is in the range of 10 to 14.

5. The method according to claim 1, wherein, In the lithium-nickel-based composite oxide, based on a total of 100 mol% of metals other than lithium, the nickel content is greater than or equal to 80 mol%.

6. The method 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 z1 O 2-b1 X b1 , in, In chemical formula 1, 0.9 ≤ a1 ≤ 1.8, 0.3 ≤ x1 ≤ 1, 0 ≤ y1 ≤ 0.7, 0 ≤ z1 ≤ 0.7, 0.9 ≤ x1 + y1 + z1 ≤ 1.1, and 0 ≤ b1 ≤ 0.1, M 1 and M 2 Each element is independently selected from one or more elements chosen from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, M 1 and M 2 They are different from each other, and X is one or more elements selected from F, P and S.

7. The method according to claim 1, wherein the cobalt content in the cobalt raw material is in the range of 1.0 mol% to 5.0 mol% based on a total of 100 mol% of metals other than lithium in the lithium-nickel-based composite oxide.

8. The method according to claim 1, wherein the molar ratio of sodium content in the sodium hydroxide to cobalt content in the cobalt raw material is in the range of 1.5:1 to 3:

1.

9. The method of claim 1, wherein the pH of the second mixed solution is in the range of 9 to 11.

10. Positive electrode active material, including: Including multiple core particles of lithium-nickel-based composite oxide; and The surface of the plurality of core particles includes a coating layer of aluminum and cobalt. The positive electrode active material further includes sodium, and The sodium content is in the range of 0.08% to 0.2% by weight, based on a total of 100% by weight of metals other than lithium in the lithium-nickel-based composite oxide.

11. The positive electrode active material according to claim 10, wherein, In the lithium-nickel-based composite oxide, based on a total of 100 mol% of metals other than lithium, the nickel content is greater than or equal to 80 mol%.

12. The positive electrode active material according to claim 10, 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 z1 O 2-b1 X b1 in, In chemical formula 1, 0.9 ≤ a1 ≤ 1.8, 0.3 ≤ x1 ≤ 1, 0 ≤ y1 ≤ 0.7, 0 ≤ z1 ≤ 0.7, 0.9 ≤ x1 + y1 + z1 ≤ 1.1, and 0 ≤ b1 ≤ 0.1, M 1 and M 2 Each element is independently selected from one or more elements chosen from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, M 1 and M 2 They are different from each other, and X is one or more elements selected from F, P and S.

13. The positive electrode active material according to claim 10, wherein the sodium content is in the range of 0.082% to 0.173% by weight, based on a total of 100% by weight of metals other than lithium in the lithium-nickel-based composite oxide.

14. The positive electrode active material according to claim 10, wherein... The positive electrode active material is prepared by the method according to any one of claims 1 to 9.

15. Positive electrode, including: current collector; and The positive electrode active material layer on the current collector, The positive electrode active material layer thereunder comprises the positive electrode active material according to any one of claims 10 to 14.

16. A rechargeable lithium battery, including: The positive electrode according to claim 15; negative electrode; and Electrolytes.

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