Conductive material paste composition for secondary battery electrode, slurry composition for secondary battery electrode, undercoating layer-equipped current collector for secondary battery electrode, electrode for secondary battery, and secondary battery
Provided is a slurry composition for a secondary battery electrode that has excellent fibrous carbon nanomaterial dispersibility and is capable of forming an electrode mixed material layer having excellent close adherence to a current collector. The slurry composition is obtained using a conductive material paste composition for a secondary battery electrode that contains a fibrous carbon nanomaterial, a binder, and a solvent. The binder includes a first copolymer that includes an alkylene structural unit and a nitrile group-containing monomer unit and has a weight average molecular weight of at least 170,000 and less than 1,500,000.
1. A conductive material paste composition for a secondary battery electrode comprising:
a fibrous carbon nanomaterial;
a binder; and
a solvent, wherein
the binder includes a first hydrogenated nitrile butadiene rubber including an alkylene structural unit and a nitrile group-containing monomer unit and having a weight average molecular weight of at least 200,000 and less than 500,000, a second hydrogenated nitrile butadiene rubber including an alkylene structural unit and a nitrile group-containing monomer unit and having a weight average molecular weight of at least 30,000 and less than 100,000, and
the second hydrogenated nitrile butadiene rubber is contained in proportion of 0.02 times or more and 0.09 times or less relative to a content of the fibrous carbon nanomaterial.
2. The conductive material paste composition for a secondary battery electrode according to claim 1 , wherein
the second hydrogenated nitrile butadiene rubber is contained in a proportion of at least 0.5 mass % and less than 50 mass % relative to total content of the binder.
3. The conductive material paste composition for a secondary battery electrode according to claim 2 , wherein
the binder further includes a fluorine-containing polymer.
4. The conductive material paste composition for a secondary battery electrode according to claim 2 , wherein
the fibrous carbon nanomaterial is one or more carbon nanotubes.
5. The conductive material paste composition for a secondary battery electrode according to claim 1 , wherein
the binder further includes a fluorine-containing polymer.
6. The conductive material paste composition for a secondary battery electrode according to claim 1 , wherein
the fibrous carbon nanomaterial is one or more carbon nanotubes.
7. The conductive material paste composition for a secondary battery electrode according to claim 1 , wherein the first hydrogenated nitrile butadiene rubber is contained in proportion of at least 0.01 times or more and 0.4 times or less relative to a content of the fibrous carbon nanomaterial.
8. The conductive material paste composition for a secondary battery electrode according to claim 1 , wherein an iodine value of the first hydrogenated nitrile butadiene rubber is 3 mg/100 mg or more and 60 mg/100 mg or less, and an iodine value of the second hydrogenated nitrile butadiene rubber is 3 mg/100 mg or more and 60 mg/100 mg or less.
9. The conductive material paste composition for a secondary battery electrode according to claim 1 , wherein
the first hydrogenated nitrile butadiene rubber includes the nitrile group-containing monomer unit in a proportion of not less than 25 mass %, and
the binder further includes a fluorine-containing polymer having a weight average molecular weight of not less than 1,000,000.
10. A slurry composition for a secondary battery electrode comprising:
an electrode active material; and
the conductive material paste composition for a secondary battery electrode according to claim 1 .
11. An electrode for a secondary battery comprising:
a current collector; and
an electrode mixed material layer formed using the slurry composition for a secondary battery electrode according to claim 10 .
12. A secondary battery comprising the electrode for a secondary battery according to claim 11 .
13. An undercoating layer-equipped current collector for a secondary battery electrode comprising:
a current collector; and
an undercoating layer on at least one surface of the current collector, wherein
the undercoating layer contains a fibrous carbon nanomaterial and a binder, and
the binder includes a first hydrogenated nitrile butadiene rubber including an alkylene structural unit and a nitrile group-containing monomer unit and having a weight average molecular weight of at least 200,000 d less than 500,000, a second hydrogenated nitrile butadiene rubber including an alkylene structural unit and a nitrile group-containing monomer unit and having a weight average molecular weight of at least 30,000 and less than 100,000, and
the second hydrogenated nitrile butadiene rubber is contained in proportion of 0.02 times or more and 0.09 times or less relative to a content of the fibrous carbon nanomaterial.
14. The undercoating layer-equipped current collector for a secondary battery electrode according to claim 13 , wherein
the second hydrogenated nitrile butadiene rubber is contained in a proportion of at least 0.5 mass % and less than 50 mass % relative to total content of the binder.
15. The undercoating layer-equipped current collector for a secondary battery electrode according to claim 14 , wherein
the fibrous carbon nanomaterial is one or more carbon nanotubes.
16. The undercoating layer-equipped current collector for a secondary battery electrode according to claim 13 , wherein
the fibrous carbon nanomaterial is one or more carbon nanotubes.