Aqueous coating composition including poly(vinylamide)-based copolymer, crosslinking agent, and inorganic particles, method for manufacturing separator by using same, separator, and lithium battery

Patent metadata

Field	Value
Publication number	US-12362429-B2
Application number	US-202218013715-A
Country	US
Kind code	B2
Filing date	May 13, 2022
Priority date	May 14, 2021
Publication date	Jul 15, 2025
Grant date	Jul 15, 2025

Abstract

Provided are a composition for coating a separator, a method of preparing a separator using the same, a separator, and a lithium battery employing the separator. The composition for coating a separator includes a binder including an aqueous cross-linking reactive poly(vinylamide)-based copolymer, a cross-linker, inorganic particles, and water, wherein the poly(vinylamide)-based copolymer includes a repeating unit derived from a vinylamide monomer, and a repeating unit derived from a cross-linking reactive group-containing monomer. The composition for coating a separator may provide a separator having high thermal resistance characteristics.

First claim

The invention claimed is:

1. A composition for coating a separator, comprising:
a binder having an aqueous cross-linking reactive poly (vinylamide)-based copolymer;
a cross-linker;
inorganic particles; and
water,
wherein:
the poly (vinylamide)-based copolymer includes a repeating unit derived from a vinylamide monomer and a repeating unit derived from a cross-linking reactive group-containing monomer,
the vinylamide monomer is selected from vinylpyrrolidone, vinylcaprolactam and mixtures thereof,
the crosslinking reactive group includes at least one selected from a carboxyl group, an isocyanate group, a hydroxyl group, and an oxazoline group, and
the cross-linker includes at least one of ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, propanediol, dipropylene glycol, polypropylene glycol, glycerin, polyglycerin, butanediol, heptanediol, hexanediol trimethylolpropane, pentaerythricol, and sorbitol.

2. The composition for coating a separator as claimed in claim 1 , wherein a content of the poly (vinylamide)-based copolymer is 10 wt % to 100 wt %, with respect to a total weight of the binder.

3. The composition for coating a separator as claimed in claim 1 , wherein a content of the cross-linker is in a range of 1 part by weight to 45 parts by weight, with respect to 100 parts by weight of the poly (vinylamide)-based copolymer.

4. The composition for coating a separator as claimed in claim 1 , wherein the inorganic particles include at least one of boehmite, alumina, aluminum oxyhydroxide (AlOOH), zirconia, yttria, ceria, magnesia, titania, silica, aluminum carbide, titanium carbide, tungsten carbide, boron nitride, aluminum nitride. calcium carbonate, barium sulfate, aluminum hydroxide, and magnesium hydroxide.

5. The composition for coating a separator as claimed in claim 1 , wherein a weight ratio of a total weight of the binder to a weight of the inorganic particles is 0.1:99.9 to 50:50.

6. The composition for coating a separator as claimed in claim 1 , wherein the poly (vinylamide)-based copolymer includes a repeating unit derived from a vinylamide monomer and a repeating unit derived from a crosslinking reactive group-containing monomer, and the repeating unit derived from a vinylamide monomer includes
a repeating unit derived from vinylpyrrolidone and the repeating unit derived from a crosslinking reactive group-containing monomer includes a repeating unit derived from (meth) acrylic acid.

7. The composition for coating a separator as claimed in claim 1 , wherein, in the poly (vinylamide)-based copolymer, a content of the repeating unit derived from a cross-linking reactive group-containing monomer is more than 0 mol % and less than 50 mol %, with respect to the total moles of monomer components constituting the poly (vinylamide)-based copolymer.

8. The composition for coating a separator as claimed in claim 1 , wherein in the poly (vinylamide)-based copolymer, a content of the repeating unit derived from a cross-linking reactive group-containing monomer is 1 mol % to 45 mol %, with respect to the total moles of monomer components constituting the poly (vinylamide)-based copolymer.

9. The separator coating composition as claimed in claim 1 , wherein the crosslinking reactive group includes at least one selected from an isocyanate group, a hydroxyl group, and an oxazoline group.

10. The composition for coating a separator as claimed in claim 1 , wherein the monomer containing the cross-linking reactive group is a monomer containing a carboxyl group.

11. The composition for coating a separator as claimed in claim 10 , wherein the carboxyl group includes at least one of acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid; monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof; and mixtures thereof.

12. A separator, comprising:
a porous substrate; and
a coating layer on one surface or both surfaces of the porous substrate, the coating layer being a dried cross-linked product of a composition, the composition including:
a binder having an aqueous cross-linking reactive poly (vinylamide)-based copolymer;
a cross-linker;
inorganic particles; and
water,

wherein:
the poly (vinylamide)-based copolymer including a repeating unit derived from a vinylamide monomer and a repeating unit derived from a cross-linking reactive group-containing monomer,
the vinylamide monomer is selected from vinylpyrrolidone, vinylcaprolactam and mixtures thereof,
the crosslinking reactive group includes at least one selected from a carboxyl group, an isocyanate group, a hydroxyl group, and an oxazoline group, and
the cross-linker includes at least one of ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, propanediol, dipropylene glycol, polypropylene glycol, glycerin, polyglycerin, butanediol, heptanediol, hexanediol trimethylolpropane, pentaerythricol, and sorbitol.

13. The separator as claimed in claim 12 , wherein the poly (vinylamide)-based copolymer is cross-linked, and the polymer has a form in which the cross-linking reactive group included in the poly (vinylamide)-based copolymer is cross-linked by the cross-linker.

14. The separator as claimed in claim 12 , wherein a thickness of the coating layer is 5% to 50% of a thickness of the porous substrate.

15. The separator coating composition as claimed in claim 12 , wherein the crosslinking reactive group includes at least one selected from an isocyanate group, a hydroxyl group, and an oxazoline group.

16. A lithium battery, comprising the separator according to claim 12 .

17. The lithium battery as claimed in claim 16 , wherein the poly (vinylamide)-based copolymer is cross-linked, and the polymer has a form in which the cross-linking reactive group included in the poly (vinylamide)-based copolymer is cross-linked by the cross-linker.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Cho Minho
• Lee Byungmin
• Kim Hana

Classifications

• H01M10/052 Primary

  Li-accumulators · CPC title

• H01M50/449

  having a layered structure · CPC title

• H01M50/491

  Porosity · CPC title

• H01M50/403

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M50/451

  comprising layers of only organic material and layers containing inorganic material · CPC title