Composition for coating separator, method for manufacturing separator by using same, separator, and lithium battery employing same

Patent metadata

Field	Value
Publication number	US-12255350-B2
Application number	US-202218013583-A
Country	US
Kind code	B2
Filing date	Feb 22, 2022
Priority date	Mar 4, 2021
Publication date	Mar 18, 2025
Grant date	Mar 18, 2025

Abstract

Provided are a composition for coating a separator, a method of preparing a separator by using the same, a separator, and a lithium battery employing the separator. The composition for coating a separator includes: a polyacrylamide-based copolymer including a cross-linking reactive group; inorganic particles; and water, and the cross-linking reactive group includes at least two functional groups cross-linkable with each other. The composition for coating a separator may be used as a one-component type without a crosslinker, and a separator having high thermal resistance characteristics may be prepared by using the composition.

First claim

The invention claimed is:

1. A composition for coating a separator, the composition comprising:
a binder including an aqueous cross-linking reactive polyacrylamide copolymer;
inorganic particles; and
water,
wherein the polyacrylamide copolymer includes at least two cross-linking reactive groups that are cross-linkable with each other,
wherein the cross-linking reactive groups include at least one first functional group selected from a carboxyl group, an amine group, and an isocyanate group; and at least one second functional group selected from a hydroxyl group, an epoxy group, and an oxazoline group, and
wherein an equivalent ratio of the first functional group and the second functional group is in a range of about 30:70 to about 70:30.

2. The composition for coating a separator of claim 1 , wherein the cross-linking reactive groups include a carboxyl group and a hydroxyl group.

3. The composition for coating a separator of claim 1 , wherein the polyacrylamide copolymer is a polymer of a monomer mixture including a N-position substituted amide monomer, the N-position substituted amide monomer including (meth) acrylamide, N,N-dialkyl (meth) acrylamide, N,N-dimethyl (meth) acrylamide, N,N-diethyl (meth) acrylamide, N,N-dipropyl (meth) acrylamide, N,N-diisopropyl (meth) acrylamide, N,N-di(n-butyl) (meth) acrylamide, N,N-di(t-butyl) (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-n-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-ethylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, or N-acryloylmorpholine.

4. The composition for coating a separator of claim 3 , wherein a content of the N-position substituted amide monomer is in a range of about 30 mol % to about 90 mol %, based on a total moles of monomer components of the monomer mixture of the polyacrylamide copolymer.

5. The composition for coating a separator of claim 1 , wherein the polyacrylamide copolymer is a copolymer of a monomer mixture that includes:
a N-position substituted amide monomer; and
an acrylic monomer, the acrylic monomer including a carboxyl group-containing monomer, a (meth) acrylic acid alkyl monomer, a hydroxyl group-containing monomer, an isocyanate group-containing monomer, an oxazoline group-containing monomer, a multifunctional (meth) acrylate monomer, an acid anhydride group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, a succinimide monomer, a maleimide monomer, an itaconimide monomer, a cyano-containing monomer, a (meth) acrylic acid aminoalkyl monomer, a (meth) acrylic acid alkoxyalkyl monomer, an epoxy group-containing acrylic monomer, an acrylic acid ester monomer including a heterocycle, a halogen atom, or a silicon atom, acryloylmorpholine, a (meth) acrylic acid ester including an alicyclic hydrocarbon group, a (meth) acrylic acid ester including an aromatic hydrocarbon group, or a (meth) acrylic acid ester obtained from a terpene compound-derived alcohol.

6. The composition for coating a separator of claim 5 , wherein a molar ratio of the N-position substituted amide monomer and the acrylic monomer is in a range of about 1:99 to about 99:1.

7. The composition for coating a separator of claim 1 , wherein the polyacrylamide copolymer is an aqueous cross-linking reactive polyacrylamide-acrylic acid-hydroxyethyl acrylic copolymer.

8. The composition for coating a separator of claim 1 , wherein a content of the polyacrylamide copolymer is about 10 wt % to about 100 wt %, with respect to a total weight of the binder.

9. The composition for coating a separator of claim 1 , wherein the inorganic particles include 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, or magnesium hydroxide.

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

11. The composition for coating a separator of claim 1 , wherein the composition for coating a separator does not include a crosslinker.

12. A separator, comprising:
a porous substrate; and
a dried cross-linked product of the composition for coating a separator according to claim 1 on one surface or both surfaces of the porous substrate.

13. The separator of claim 12 , wherein the coating layer includes:
a binder including the aqueous cross-linking reactive polyacrylamide copolymer; and
inorganic particles, wherein two or more cross-linking reactive groups included in the polyacrylamide copolymer have a mutually cross-linked form.

14. The separator of claim 12 , wherein the separator has a basis weight ratio of less than 0.6 as calculated by Equation 1 below:
Basis weight ratio=unit weight of coating layer/unit weight of porous substrate.  <Equation 1>

15. The separator of claim 14 , wherein the separator has a basis weight ratio of less than 0.45.

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

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Hana
• Lee Byungmin
• Cho Minho

Classifications

• H01M50/42

  Acrylic resins · CPC title

• H01M50/443

  Particulate material · CPC title

• H01M50/403

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title