Binder composition for secondary battery positive electrode, slurry composition for secondary battery positive electrode and method of producing same, positive electrode for secondary battery, and secondary battery

Patent metadata

Field	Value
Publication number	US-11742489-B2
Application number	US-201816958151-A
Country	US
Kind code	B2
Filing date	Dec 14, 2018
Priority date	Dec 28, 2017
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

A binder composition for a secondary battery positive electrode contains a polymer including a nitrile group-containing monomer unit, an aromatic vinyl monomer unit, a hydrophilic group-containing monomer unit, a conjugated diene monomer unit, and a linear alkylene structural unit having a carbon number of 4 or more. The aromatic vinyl monomer unit is included in the polymer in a proportion of not less than 30.0 mass % and not more than 60.0 mass %. The polymer has an iodine value of not less than 60 mg/100 mg and not more than 150 mg/100 mg.

First claim

The invention claimed is:

1. A binder composition for a secondary battery positive electrode comprising a polymer, wherein
the polymer includes a nitrile group-containing monomer unit, an aromatic vinyl monomer unit, a hydrophilic group-containing monomer unit, a conjugated diene monomer unit, and a linear alkylene structural unit having a carbon number of 4 or more,
the aromatic vinyl monomer unit is included in the polymer in a proportion of not less than 30.0 mass % and not more than 60.0 mass %,
the nitrile group-containing monomer unit is included in the polymer in a proportion of not less than 10 mass %,
a total proportion of the conjugated diene monomer unit and the linear alkylene structural unit having a carbon number of 4 or more is 10.0 mass % or more and 50.0 mass % or less,
the polymer has an iodine value of not less than 75 mg/100 mg and not more than 150 mg/100 mg, and
the polymer has a Mooney viscosity (ML 1+4 , 100° C.) of 70 or more and 200 or less.

2. The binder composition for a secondary battery positive electrode according to claim 1 , wherein
when a total proportion in which the conjugated diene monomer unit and the linear alkylene structural unit having a carbon number of 4 or more are included in the polymer is taken to be A mass %,
a proportion in which the aromatic vinyl monomer unit is included in the polymer is taken to be B mass %, and
the iodine value of the polymer is taken to be IV (mg/100 mg),
a relationship of 10≤{A/(A+B)}×IV≤90 is satisfied.

3. The binder composition for a secondary battery positive electrode according to claim 1 , wherein the polymer includes an acidic group-containing monomer unit in a proportion of not less than 0.1 mass % and not more than 20.0 mass % as the hydrophilic group-containing monomer unit.

4. The binder composition for a secondary battery positive electrode according to claim 1 , wherein the polymer further includes a (meth)acrylic acid ester monomer unit.

5. The binder composition for a secondary battery positive electrode according to claim 4 , wherein the polymer includes the (meth)acrylic acid ester monomer unit in a proportion of not less than 1.0 mass % and not more than 20.0 mass %.

6. A slurry composition for a secondary battery positive electrode comprising: a positive electrode active material; a solvent; and the binder composition for a secondary battery positive electrode according to claim 1 .

7. A positive electrode for a secondary battery comprising a positive electrode mixed material layer formed using the slurry composition for a secondary battery positive electrode according to claim 6 .

8. A secondary battery comprising: the positive electrode for a secondary battery according to claim 7 ; a negative electrode; an electrolyte solution; and a separator.

9. A method of producing a slurry composition for a secondary battery positive electrode comprising, in stated order:
mixing a positive electrode active material and a conductive material to obtain a positive electrode active material-conductive material mixture;
adding the binder composition for a secondary battery positive electrode according to claim 1 to the positive electrode active material-conductive material mixture to obtain a positive electrode active material-conductive material-binder mixture; and
adding a solvent to the positive electrode active material-conductive material-binder mixture and mixing the solvent therewith.

Assignees

• Zeon Corp

Inventors

• Sonobe Kenya
• Oguro Hiroki
• MESUDA Maki

Classifications

• H01M4/622 Primary

  being polymers · CPC title

• C08F220/18

  with acrylic or methacrylic acids · CPC title

• C08F236/10

  with vinyl-aromatic monomers · CPC title

• C08F236/12

  with nitriles · CPC title

• H01M4/139

  Processes of manufacture · CPC title