Positive electrode, preparation method thereof, and rechargeable lithium batteries

Patent metadata

Field	Value
Publication number	US-2025391870-A1
Application number	US-202519237789-A
Country	US
Kind code	A1
Filing date	Jun 13, 2025
Priority date	Jun 21, 2024
Publication date	Dec 25, 2025
Grant date	—

Abstract

Disclosed are a positive electrode, a preparation method thereof, and a rechargeable lithium battery including the same, the positive electrode including a positive electrode current collector; and a positive electrode active material layer located on the positive electrode current collector and including a positive electrode active material, a binder, and a conductive material; wherein the binder includes a first binder and a second binder, the first binder is a hydrogenated nitrile butadiene rubber, the second binder includes an imide-based binder, and the positive electrode active material layer includes about 300 to about 1,300 parts by weight of the second binder based on 100 parts by weight of the first binder.

First claim

What is claimed is:

1 . A positive electrode, comprising
a positive electrode current collector; and a positive electrode active material layer located on the positive electrode current collector and including a positive electrode active material, a binder, and a conductive material; wherein the binder comprises a first binder and a second binder, the first binder comprises a hydrogenated nitrile butadiene rubber, the second binder comprises an imide-based binder, and the positive electrode active material layer comprises about 300 to about 1,300 parts by weight of the second binder based on 100 parts by weight of the first binder.

2 . The positive electrode as claimed in claim 1 , wherein
the first binder is a positive electrode has a weight average molecular weight (Mw) of about 100,000 g/mol to about 2,000,000 g/mol.

3 . The positive electrode as claimed in claim 1 , wherein
the hydrogenated nitrile butadiene rubber comprises about 20 to about 40 wt % of acrylonitrile or methacrylonitrile.

4 . The positive electrode as claimed in claim 1 , wherein
the second binder comprises polyimide, poly(imide-amide), poly(imide-urethane), poly(imide-urea), or a combination thereof.

5 . The positive electrode as claimed in claim 1 , wherein
the second binder comprises at least one of a structure represented by Chemical Formula 1A and a structure represented by Chemical Formula 1B:

wherein, in Chemical Formula 1A, R 1 represents hydrogen, deuterium, or a substituted or unsubstituted alkyl group, x1 is an integer from 0 to 3, and * represents a linking portion. [Chemical Formula 1B]

wherein, in Chemical Formula 1B, R 2 is hydrogen, deuterium, or a substituted or unsubstituted alkyl group, x2 is an integer from 0 to 2, and * represents a linking portion.

6 . The positive electrode as claimed in claim 1 , wherein
the second binder comprises at least one of a structure represented by Chemical Formula 2A and a structure represented by Chemical Formula 2B:

wherein, in Chemical Formula 2A, R 11 to R 15 are each independently hydrogen, deuterium, or a substituted or unsubstituted alkyl group, x11 is an integer ranging from 0 to 3, y12 and z13 are each independently an integer ranging from 0 to 4, and * represents a linking portion,

wherein, in Chemical Formula 2B, R 21 to R 25 are each independently hydrogen, deuterium, or a substituted or unsubstituted alkyl group, x21 is an integer ranging from 0 to 2, y22 and z23 are each independently an integer ranging from 0 to 4, and * represents a linking portion.

7 . The positive electrode as claimed in claim 1 , wherein
the second binder has an expansion coefficient P value with respect to the electrolyte solution of about 10 wt % to about 50 wt %.

8 . The positive electrode as claimed in claim 1 , wherein
the second binder has an elastic elongation of about 10% to about 200% after immersion in an electrolyte solution for 24 hours.

9 . The positive electrode as claimed in claim 1 , wherein
the positive electrode active material layer comprises about 3 to about 20 wt % of the first binder based on 100 wt % of the total of the first binder and the second binder.

10 . The positive electrode as claimed in claim 1 , wherein
the positive electrode active material layer comprises about 80 to about 97 wt % of the second binder based on 100 wt % of the total of the first binder and the second binder.

11 . The positive electrode as claimed in claim 1 , wherein
the positive electrode active material comprises a lithium transition metal composite oxide.

12 . The positive electrode as claimed in claim 1 , wherein
the positive electrode active material comprises a lithium composite phosphate, and the lithium composite phosphate is at least one compound represented by Chemical Formulas 11 to 15:

wherein, in Chemical Formula 11, 0.90≤a1≤1.5, 0≤s1≤0.4, and M 1 is Al, Ca, Ce, Cr, Cu, La, Mg, Mn, Mo, Nb, Ni, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof,

wherein, in Chemical Formula 12, 0.90≤a2≤1.5, 0.1≤s2≤0.9, 0≤12≤0.9, and M 2 is Al, Ca, Ce, Cr, Cu, La, Mg, Mo, Nb, Ni, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof,

wherein, in Chemical Formula 13, 0.90≤a3≤1.5, 0≤s3≤0.4, and M 3 is Al, Ca, Ce, Cr, Cu, La, Mg, Mo, Nb, Ni, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof,

wherein, in Chemical Formula 14, 0.90≤a4≤1.5, 0≤s4≤0.4, and M 4 is Al, Ca, Ce, Cr, Cu, La, Mg, Mo, Nb, Ni, Sn, Sr, V, W, Y, Zn, Zr, or a combination thereof,

wherein, in Chemical Formula 15, 0.90≤a5≤1.5, 0≤s5≤0.4, and M 5 is Al, Ca, Ce, Cr, Cu, La, Mg, Mo, Nb, Ni, Sn, Sr, V, W, Y, Zn, Zr, or a combination thereof.

13 . The positive electrode as claimed in claim 1 , wherein
the first binder and the second binder do not comprise fluorine.

14 . A method of preparing a positive electrode, comprising
preparing a positive electrode slurry including a positive electrode active material, a binder, and a conductive material, coating the positive electrode slurry on the positive electrode current collector to form a positive electrode, wherein the binder comprises a first binder and a second binder, the first binder comprises a hydrogenated nitrile butadiene rubber, the second binder comprises an imide-based binder, and the positive electrode slurry comprises about 300 to about 1,300 parts by weight of the second binder based on 100 parts by weight of the first binder.

15 . The method as claimed in claim 14 , wherein
the positive electrode slurry is prepared by mixing a first binder, a conductive material, and a solvent to prepare a dispersibility of a conductive material, adding a second binder to the dispersibility of a conductive material to prepare a mixed solution, and mixing a positive electrode active material into the mixed solution.

16 . A rechargeable lithium battery, comprising
the positive electrode as claimed in claim 1 ; a negative electrode; and an electrolyte.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Choi Jewon
• Kim Eunji
• Cho Yunshik
• Jung Kyunghwa
• Lee Kukjoo
• Park Sujin
• Cho Minho
• Lee Jungmin
• Nam Junghyun

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/1397

  of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title