Binder composition for secondary battery, and electrode for secondary battery and lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-10862126-B2
Application number	US-201615761600-A
Country	US
Kind code	B2
Filing date	Dec 22, 2016
Priority date	Dec 24, 2015
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

The present invention relates to a binder composition for a secondary battery, including: a copolymer having a functional group; and an alkali metal ion bound to the functional group of the copolymer or with which a constituent element of the functional group is substituted. The binder composition exhibits enhanced adhesive strength and also exhibits low resistance due to the alkali metal ion included in the copolymer, and thus may exhibit more stable electrochemical performance.

First claim

The invention claimed is:

1. A binder composition for a secondary battery comprising:
a copolymer having a functional group; and
an alkali metal ion bound to the functional group of the copolymer,
wherein the alkali metal ion is included in an amount of 0.2 parts by weight to 5 parts by weight with respect to 100 parts by weight of the copolymer, and
the copolymer comprises both a conjugated diene-based copolymer A and an acryl-based copolymer B,

wherein the conjugated diene-based copolymer A comprises:
(a) a repeating unit derived from a conjugated diene-based monomer or a unit derived from a conjugated diene-based polymer;
(c) one or more repeating units selected from the group consisting of a repeating unit derived from a vinyl-based monomer, a repeating unit derived from a (meth)acrylamide-based monomer, and a repeating unit derived from a nitrile-based monomer; and
(d) a repeating unit derived from an unsaturated carboxylic acid-based monomer; and

wherein the acryl-based copolymer B comprises:
(b) a repeating unit derived from a (meth)acrylic acid ester-based monomer;
(c) one or more repeating units selected from the group consisting of a repeating unit derived from a vinyl-based monomer, a repeating unit derived from a (meth)acrylamide-based monomer, and a repeating unit derived from a nitrile-based monomer; and
(d) a repeating unit derived from an unsaturated carboxylic acid-based monomer,
wherein the (meth)acrylic acid ester-based monomer is one or more selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-ethyl hexyl acrylate, 2-ethyl hexyl acrylate, 2-hydroxy ethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, n-ethyl hexyl methacrylate, 2-ethyl hexyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, methacryloxyethyl ethylene urea, β-carboxy ethyl acrylate, aliphatic monoacrylate, dipropylene diacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, lauryl acrylate, seryl acrylate, stearyl acrylate, lauryl methacrylate, cetyl methacrylate, and stearyl methacrylate;
the vinyl-based monomer is one or more selected from the group consisting of α-methylstyrene, β-methylstyrene, p-t-butylstyrene, and divinylbenzene;
the (meth)acrylamide-based monomer is one or more selected from the group consisting of acrylamide, n-methylol acrylamide, n-butoxy methylacrylamide, methacrylamide, n-methylol methacrylamide, and n-butoxy methylmethacrylamide; and
the unsaturated carboxylic acid-based monomer is one or more selected from the group consisting of maleic acid, fumaric acid, methacrylic acid, acrylic acid, glutaric acid, itaconic acid, tetrahydrophthalic acid, crotonic acid, isocrotonic acid, and nadic acid.

2. The binder composition of claim 1 , wherein the alkali metal ion comprises one or more selected from the group consisting of a lithium ion, a sodium ion, a potassium ion, a rubidium ion, a cesium ion, and a francium ion.

3. The binder composition of claim 1 , wherein the binder composition comprises 1 part by weight to 30 parts by weight of the acryl-based copolymer B based on 100 parts by weight of total solids of the binder composition.

4. The binder composition of claim 1 , wherein the conjugated diene-based copolymer A comprises, based on a total weight (100 parts by weight) of the conjugated diene-based copolymer A,
10 parts by weight to 97.9 parts by weight of the repeating unit derived from a conjugated diene-based monomer or the unit derived from a conjugated diene-based polymer (a);
1 part by weight to 60 parts by weight of the one or more repeating units selected from the group consisting of a repeating unit derived from a vinyl-based monomer, a repeating unit derived from a (meth)acrylamide-based monomer, and a repeating unit derived from a nitrile-based monomer (c); and
1 part by weight to 20 parts by weight of the repeating unit derived from an unsaturated carboxylic acid-based monomer (d).

5. The binder composition of claim 1 , wherein the acryl-based copolymer B comprises, based on a total weight (100 parts by weight) of the acryl-based copolymer B,
10 parts by weight to 97.9 parts by weight of the repeating unit derived from a (meth)acrylic acid ester-based monomer (b);
1 part by weight to 60 parts by weight of the one or more repeating units selected from the group consisting of a repeating unit derived from a vinyl-based monomer, a repeating unit derived from a (meth)acrylamide-based monomer, and a repeating unit derived from a nitrile-based monomer (c); and
1 part by weight to 20 parts by weight of the repeating unit derived from an unsaturated carboxylic acid-based monomer (d).

6. The binder composition of claim 1 , wherein the nitrile-based monomer is an alkenyl cyanide.

7. The binder composition of claim 6 , wherein the alkenyl cyanide comprises one or more selected from the group consisting of acrylonitrile, methacrylonitrile, and allyl cyanide.

8. An electrode for a secondary battery, the electrode comprising the binder composition according to claim 1 .

9. A lithium secondary battery comprising the electrode according to claim 8 .

Assignees

• Lg Chemical Ltd

Inventors

• Kang Min Ah
• Ryu Dong Jo
• Han Seon Hee
• Choi Cheol Hoon
• Han Hye Soo

Classifications

• C08F220/18

  with acrylic or methacrylic acids · CPC title

• C08C19/36

  with carboxy radicals · CPC title

• C08L33/26

  Homopolymers or copolymers of acrylamide or methacrylamide · CPC title

• H01M10/052

  Li-accumulators · CPC title

• C08L15/00

  Compositions of rubber derivatives (C08L11/00, C08L13/00 take precedence) · CPC title