Conductive material dispersion, coating and secondary battery
A conductive material dispersion containing a dispersant that satisfies the following (1) and (2), a carbon-based conductive material (C), and a medium (D) containing at least water. (1) Contains a polymer (A) having one or more selected from the group consisting of nitrile group-containing structural units, carboxyl group-containing structural units, hydroxyl group-containing structural units, and heterocycle-containing structural units and having a weight average molecular weight of 5,000 or more and 360,000 or less. (2) Contains a component (B) other than a polymer and derived from the raw materials of the polymer (A); and the content of the component (B) is 2 mass % or less based on the total mass of the dispersant.
1 . A conductive material dispersion comprising a dispersant that includes the following (1) and (2), a carbon-based conductive material (C), and a medium containing at least water (D):
(1) a polymer (A) containing one or more selected from the group consisting of nitrile group-containing structural units, carboxyl group-containing structural units, hydroxyl group-containing structural units, and heterocycle-containing structural units and having a weight average molecular weight of 5,000 or more and 360,000 or less, and
(2) a component (B) other than a polymer and derived from a raw material of the polymer (A), and a content of the component (B) based on a total mass of the dispersant being 1.9 mass % or less,
wherein the component (B) contains one or more selected from the group consisting of unreacted raw materials and by-products generated in a polymerization reaction or a modification reaction of the polymer (A),
wherein the carbon-based conductive material (C) includes carbon nanotubes having an average fiber length of 0.3 μm or more.
2 . The conductive material dispersion according to claim 1 ,
wherein the polymer (A) includes 5 mass % or less of a polymer (E) having a molecular weight of less than 1,000 based on the total mass of the polymer (A).
3 . The conductive material dispersion according to claim 1 ,
wherein a complex elastic modulus at 25° C. and 1 Hz obtained by dynamic viscoelasticity measurement is 5 Pa or more and less than 650 Pa.
4 . The conductive material dispersion according to claim 1 ,
wherein a phase angle at 25° C. and 1 Hz obtained by dynamic viscoelasticity measurement is 3° or more and less than 60°.
5 . The conductive material dispersion according to claim 1 , further comprising a binder.
6 . The conductive material dispersion according to claim 1 , further comprising an electrode active material.
7 . A coating formed using the conductive material dispersion according to claim 1 .
8 . A secondary battery comprising the coating according to claim 7 .