Dispersant composition for electrochemical device, conductive material dispersion liquid for electrochemical device, slurry composition for electrochemical device electrode and method of producing same, electrode for electrochemical device, and electrochemical device
A dispersant composition for an electrochemical device contains a polymer including a nitrile group-containing monomer unit and an alkylene structural unit. Upon measurement of the polymer contained in the composition by dynamic light scattering, a value (A) detected for volume-average particle diameter D50 is not less than 50 nm and not more than 800 nm, and one or more peaks are detected in a particle diameter range of not less than 5 μm and not more than 30 μm.
1 . A dispersant composition for an electrochemical device comprising a polymer including a nitrile group-containing monomer unit and an alkylene structural unit, wherein
the alkylene structural unit is a repeating unit represented by a general formula: —C n H 2n — (n is an integer of 2 or more),
upon measurement of the polymer by dynamic light scattering, a value (A) detected for volume-average particle diameter D50 is not less than 50 nm and not more than 450 nm, and one or more peaks are detected in a particle diameter range of not less than 5 μm and not more than 30 μm, wherein the one or more peaks detected in the range of not less than 5 μm and not more than 30 μm corresponds to size of clusters formed by a plurality of polymer molecules, and
when a value for a particle diameter corresponding to a largest peak among the one or more peaks that are detected in the particle diameter range of not less than 5 μm and not more than 30 μm upon measurement of the polymer by dynamic light scattering is taken to be (B),
a parameter (B/A) that is obtained by dividing the value (B) for the particle diameter by the value (A) for the volume-average particle diameter D50 has a value of not less than 7 and not more than 200, and
an iodine value of the polymer is 50 mg/100 mg or less.
2 . The dispersant composition for an electrochemical device according to claim 1 , wherein proportional content of the nitrile group-containing monomer unit in the polymer is not less than 10 mass % and not more than 60 mass %.
3 . The dispersant composition for an electrochemical device according to claim 1 , further comprising not less than 0.01 mass % and not more than 0.2 mass % of a substituted phenol compound based on total mass of the polymer.
4 . A conductive material dispersion liquid for an electrochemical device comprising: a conductive material; a solvent; and the dispersant composition for an electrochemical device according to claim 1 .
5 . A slurry composition for an electrochemical device electrode comprising: an electrode active material; a conductive material; and the dispersant composition for an electrochemical device according to claim 1 .
6 . A method of producing the slurry composition for an electrochemical device electrode according to claim 5 comprising:
a first step of mixing the polymer, the conductive material, and a solvent to produce a conductive material dispersion liquid; and
a second step of mixing the conductive material dispersion liquid obtained in the first step and the electrode active material.
7 . An electrode for an electrochemical device comprising an electrode mixed material layer formed using the slurry composition for an electrochemical device electrode according to claim 5 .
8 . An electrochemical device comprising the electrode for an electrochemical device according to claim 7 .
9 . The dispersant composition for an electrochemical device according to claim 1 , wherein an iodine value of the polymer is 1 mg/100 mg or more and 40 mg/100 mg or less.