Dispersant for electric power storage device electrode

Abstract

The present disclosure relates to a dispersant for an electric power storage device electrode, the dispersant in one aspect being a polymer comprising a constituent unit (A) that is expressed by general formula (1) and a constituent unit (B) that is expressed by general formula (2), wherein a molar fraction a of the constituent unit (A) with respect to all constituent units of the polymer is 0.30 or more. In general formula (1), R1 is a C1-14 hydrocarbon group that may include hydrogen or a hydroxyl group, R2 is a C1-14 hydrocarbon group that may include a hydroxyl group, and M is hydrogen, NH4, a metal, or organic ammonium. In general formula 2, R3 is hydrogen or a methyl group, and R4 is a C16-22 hydrocarbon group.

Description

Dispersants for electrodes of power storage devices

[0001] The present invention relates to a dispersant for an electrode of an electricity storage device.

[0002] In recent years, the development of electric vehicles that do not emit carbon dioxide has been actively pursued in order to curb global warming. Electric vehicles have the drawback of having a shorter driving range and longer battery charging times than gasoline-powered vehicles. To shorten charging times, it is necessary to increase the electron transfer rate in the positive electrode. Currently, carbon materials are used as conductive materials in the positive electrodes of non-aqueous electrolyte batteries. However, the use of carbon materials increases the viscosity of conductive material slurries and positive electrode pastes, which makes them difficult to handle, and there is a demand for lower viscosity slurries and pastes. The viscosity of slurries and pastes is significantly affected by the dispersibility of the carbon material.

[0003] Japanese Patent Publication No. 41-17852 (Patent Document 1) discloses a dispersant for use in non-aqueous polar solvents, obtained by reacting a copolymer of diisobutylene and maleic anhydride with ammonia or a saturated lower amine at a reaction rate of nearly 100%. Japanese Patent Application Laid-Open No. 2018-168285 (Patent Document 2) discloses a dispersant composition for printing inks, containing a 100% amidation product of a copolymer of diisobutylene and maleic anhydride with stearylamine and methyl isobutyl ketone (MIBK) as an organic solvent. Japanese Patent Application Laid-Open No. 2009-138115 (Patent Document 3) discloses an oil-based dispersant composition for electronic materials, containing a amide product of a copolymer of diisobutylene and maleic anhydride with oleylamine and propylene glycol methyl ether acetate (PEGMA) as an organic solvent.

[0004] In one aspect, the present disclosure relates to a dispersant for an electrode of an electricity storage device, which is a polymer including a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), wherein the molar fraction a of the structural unit (A) relative to all structural units of the polymer is 0.30 or more: However, in the above general formula (1), R 1 is hydrogen or a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group, and R2 is a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group, M is hydrogen, NH4, a metal or an organic ammonium, and in the above general formula (2), R 3 is hydrogen or a methyl group, and R 4 is a hydrocarbon group having 16 to 22 carbon atoms.

[0005] In one aspect, the present disclosure relates to a dispersant composition for an electrical storage device electrode, comprising the dispersant for an electrical storage device electrode of the present disclosure and an organic solvent.

[0006] In one aspect, the present disclosure relates to a carbonaceous conductive material slurry containing the dispersant for an electrical storage device electrode of the present disclosure, a carbonaceous conductive material, and an organic solvent.

[0007] In one aspect, the present disclosure relates to a positive electrode paste for an electricity storage device, comprising the dispersant for an electricity storage device electrode of the present disclosure, a carbon material-based conductive material, a positive electrode active material, and an organic solvent.

[0008] In one aspect, the present disclosure relates to a method for producing a positive electrode for an electricity storage device, the method comprising applying the positive electrode paste for an electricity storage device of the present disclosure to a current collector and drying the applied paste.

[0009] In one aspect, the present disclosure relates to a method for producing an electricity storage device, which includes incorporating a positive electrode for an electricity storage device obtained by the method for producing a positive electrode for an electricity storage device of the present disclosure.

[0010] In one aspect, the present disclosure provides a dispersant for carbon materials, which is a polymer including a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), wherein the molar fraction a of the structural unit (A) relative to all structural units of the polymer is 0.30 or more: However, in the above general formula (1), R 1 is a hydrocarbon group having 1 to 14 carbon atoms which may have hydrogen or a hydroxyl group, and R 2 is a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group, M is hydrogen, NH4, a metal or an organic ammonium, and in the above general formula (2), R 3 is hydrogen or a methyl group, and R 4is a hydrocarbon group having 16 to 22 carbon atoms.

[0011] In Patent Literature 1, it is stated that dispersants used to disperse carbon materials in non-aqueous solvents are particularly effective in nonpolar solvents, while dispersants having a long-chain alkyl group introduced therein are particularly effective in polar solvents. Meanwhile, while further reduction in resistance of storage battery device electrodes due to the good dispersibility of carbon material-based conductive materials is desired, dispersants having a short-chain alkyl group introduced therein, which are stated in Patent Literature 1 to be effective for dispersing carbon black, have a problem in that they have low dispersibility in polar solvents used to manufacture storage battery device electrodes. This problem is particularly pronounced when the carbon material-based conductive material is carbon nanotubes with a high aspect ratio.

[0012] In recent years, reducing the viscosity of positive electrode pastes has become an issue for forming low-resistance positive electrode coatings, and therefore further improvement in the dispersibility of carbonaceous conductive materials in the conductive material slurries used to prepare positive electrode pastes is desired, because the dispersibility of carbonaceous conductive materials is a controlling factor that greatly affects the viscosity of positive electrode pastes.

[0013] Patent Documents 2 and 3 disclose an amidated copolymer of diisobutylene and maleic anhydride as a dispersant, similar to Patent Document 1, and Patent Document 2 discloses a dispersant composition for printing ink containing carbon black as a pigment, while Patent Document 3 discloses a dispersant composition for electronic materials containing carbon black. However, these disclosures do not relate to improving the dispersibility of carbon material-based conductive materials in polar solvents used in the production of electrodes for storage battery devices.

[0014] Therefore, in one aspect, the present disclosure provides a dispersant for an electrode of an electricity storage device that enables the preparation of a conductive material slurry with good dispersibility of a carbon material-based conductive material. The present disclosure also provides a dispersant composition for an electrode of an electricity storage device, a conductive material slurry, and a positive electrode paste, each containing the dispersant for an electricity storage device. The present disclosure also provides a method for producing a positive electrode for an electricity storage device using the positive electrode paste, and a method for producing an electricity storage device using the positive electrode for an electricity storage device. The present disclosure also provides a carbon material dispersant that enables good dispersion of a carbon material-based conductive material in an organic solvent.

[0015] The present disclosure is based on the new finding that a carbon material-based conductive material slurry (hereinafter also referred to as "conductive material slurry") having good dispersibility of a carbon material-based conductive material can be prepared by using, as a dispersant, a polymer which includes a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), and in which the molar fraction a of the structural unit (A) relative to all structural units is 0.30 or more: However, in the above general formula (1), R 1 is a hydrocarbon group having 1 to 14 carbon atoms which may have hydrogen or a hydroxyl group, and R 2 is a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group, M is hydrogen, NH4, a metal or an organic ammonium, and in the above general formula (2), R 3 is hydrogen or a methyl group, and R 4 is a hydrocarbon group having 16 to 22 carbon atoms.

[0016] Although the details of the mechanism by which the effects of the present disclosure are manifested are not clear, it is presumed as follows.

[0017] In order for a polymeric dispersant to exhibit excellent adsorption properties to a carbonaceous conductive material, the dispersant must have a hydrocarbon group of a specific chain length on its side chain, specifically, a hydrocarbon group R having 16 to 22 carbon atoms. 4 On the other hand, it has been found that it is necessary for the polymer to contain a hydrocarbon group R 4Inclusion of the following R is generally considered to be disadvantageous from the viewpoint of the solubility of the dispersant in a polar solvent, since the hydrophobicity of the polymer increases and the solubility of the polymer in a polar solvent (organic solvent) decreases. 1 and R 2 These R 1 and R 2 is hydrogen or a hydrocarbon group having a small number of carbon atoms which may have a hydroxyl group, so R 1 and R 2 contributes appropriately to the dissolution of the dispersant in the polar solvent. Furthermore, the carboxy group of the structural unit (A) or the salt structure obtained by neutralizing the carboxy group contributes to improving the dispersibility of the carbon material-based conductive material in the polar solvent through its electrostatic repulsion. Therefore, it is presumed that the dispersant for an electrical storage device electrode of the present disclosure has appropriate solubility in polar solvents and excellent adsorption properties for the carbon material-based conductive material, and further, by generating the electrostatic repulsion between the dispersant and the carbon material-based conductive material, it enables high dispersion of the carbon material-based conductive material. However, the present disclosure should not be interpreted as being limited to these mechanisms.

[0018] According to one aspect of the present disclosure, a dispersant for an electricity storage device electrode can be provided, which enables the preparation of a conductive material slurry having good dispersibility of a carbon material-based conductive material. According to one aspect of the present disclosure, a dispersant composition for an electricity storage device electrode can be provided, which enables the preparation of a carbon material-based conductive material slurry having good dispersibility of a carbon material-based conductive material. According to one aspect of the present disclosure, a carbon material-based conductive material slurry can be provided, which includes the dispersant for an electricity storage device electrode of the present disclosure and has good dispersibility of a carbon material-based conductive material. According to one aspect of the present disclosure, a positive electrode paste for an electricity storage device can be provided, which includes the dispersant for an electricity storage device electrode of the present disclosure and is capable of forming a positive electrode coating film having a low resistance value. According to one aspect of the present disclosure, a positive electrode for an electricity storage device is produced using the positive electrode paste for an electricity storage device of the present disclosure, thereby enabling the production of a positive electrode for an electricity storage device with low resistance. According to one aspect of the present disclosure, a positive electrode for an electricity storage device is produced using the positive electrode for an electricity storage device of the present disclosure, thereby enabling the production of a low-resistance electricity storage device. According to one aspect of the present disclosure, it is possible to provide a dispersant for carbon materials that enables good dispersion of a carbon material-based conductive material in an organic solvent.

[0019] <Dispersant for Electricity Storage Device Electrodes> In one aspect, the present disclosure relates to a dispersant for electrodes of electricity storage devices such as non-aqueous secondary batteries. In one aspect, the present disclosure relates to a dispersant for electricity storage device electrodes (hereinafter also referred to as the “dispersant of the present disclosure”), which is a polymer containing a structural unit (A) represented by the above general formula (1) and a structural unit (B) represented by the above general formula (2), wherein the molar fraction a of the structural unit (A) relative to all structural units of the polymer is 0.30 or more.

[0020] The dispersant of the present disclosure can be prepared, for example, by amidating a copolymer of a vinyl ether monomer and maleic anhydride to obtain R 1 and R 2 The amine used for the amidation may be one obtained by introducing R 1 and R 2The structural unit (B) is a primary or secondary amine containing the following structural unit (C): The structural unit (B) is derived from a vinyl ether monomer. For example, when a copolymer of a vinyl ether monomer and maleic anhydride is amidated and the amidation is carried out on a portion of the maleic anhydride, the dispersant of the present disclosure further contains a structural unit (C) derived from maleic anhydride represented by the following general formula (3):

[0021] The arrangement of the structural units (A) and (B) may be either block or random, but from the viewpoint of polymer productivity, a random arrangement is preferred.

[0022] Among the structural units (A), R 1 and R 2 is a component that is responsible for the solubility of the dispersant in an organic solvent, and the carboxy group or neutralized carboxy group (COOM) is a component that contributes to the dispersion of the dispersant in an organic solvent (polar solvent). 4 is a hydrophobic group, and is a component that functions as an adsorptive group for the carbon material-based conductive material.

[0023] In the above general formula (1), R 1 and R 2 are each independently a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group (provided that R 1 may be hydrogen), and the hydrocarbon group which may have a hydroxyl group is preferably a linear or branched alkyl group, more preferably a linear alkyl group which does not have a hydroxyl group, from the viewpoint of ease of synthesis of the dispersant and the solubility of the dispersant. 1 is preferably hydrogen. The number of carbon atoms in the hydrocarbon group which may have a hydroxyl group is 1 or more from the viewpoint of ease of synthesis of the dispersant and solubility of the dispersant, and is preferably 10 or less, more preferably 6 or less, and even more preferably 4 or less from the viewpoint of solubility of the dispersant in an organic solvent. 1 and R 2 are hydrocarbon groups having 1 to 14 carbon atoms, R 1 and R 2From the viewpoint of the solubility of the dispersant in an organic solvent, the total number of carbon atoms is preferably 14 or less, more preferably 10 or less, even more preferably 6 or less, and still more preferably 4 or less.

[0024] When the dispersant is obtained by amidating a copolymer of a vinyl ether monomer and maleic anhydride, the R 1 and R 2 Examples of primary or secondary amines containing the above include methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, n-butylamine, sec-butylamine, iso-butylamine, di-n-butylamine, pentylamine, hexylamine, heptylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, methylbenzylamine, N-butylaminoethanol, 1-phenylmethanamine, N-ethylaminoethanol, N-methylaminoethanol, 1-amino-2-butanol, 2-(ethylamino)ethanol, 2-amino-2-methyl-1-propanol, 1-amino-2-propanol, 1-(2-hydroxyethyl)piperazine, ethanolamine, and diethanolamine, and these may be used alone or in combination. Among these, at least one selected from iso-butylamine, tetradecylamine, hexylamine, diethylamine, 1-amino-2-butanol, and diethanolamine is preferred, at least one selected from iso-butylamine, hexylamine, diethylamine, 1-amino-2-butanol, and diethanolamine is preferred, and at least one selected from iso-butylamine, hexylamine, and 1-amino-2-butanol is more preferred.

[0025] In the above general formula (1), the carboxyl group may be unneutralized, or may be partially or completely neutralized. For example, when the carboxyl group is unneutralized, M is hydrogen. When the carboxyl group is partially or completely neutralized, M is NH4, or a metal or organic ammonium that forms a salt soluble in the organic solvent that constitutes the dispersant composition or conductive slurry. Examples of the metal include Li, Na, K, Ca, and Mg. Examples of neutralizing agents that provide these structures include ammonia, the organic amine B1 described below, and alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide.

[0026] Specific examples of the organic amine B1 are not particularly limited as long as they function as a neutralizing agent, and include, for example, methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, n-butylamine, sec-butylamine, iso-butylamine, di-n-butylamine, pentylamine, hexylamine, heptylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, dimethylbenzylamine, methyl ... Examples of amine compounds include 1-amino-2-butanol, 2-(ethylamino)ethanol, 2-amino-2-methyl-1-propanol, DL-1-amino-2-propanol, N-methyl-2-aminoethanol, 1-(2-hydroxyethyl)piperazine, and N-ethyldiethanolamine, and these may be used alone or in combination. Among these, 2-amino-2-methyl-1-propanol is preferred.

[0027] In the above general formula (2), R 3 is hydrogen or a methyl group, and is preferably hydrogen from the viewpoint of the solubility of the dispersant in an organic solvent.

[0028] In the above general formula (2), R 4R is a hydrocarbon group having 16 to 22 carbon atoms, and the hydrocarbon group is preferably a linear or branched alkyl group from the viewpoint of the adsorption of the dispersant to the carbon material-based conductive material. 4 The number of carbon atoms is 16 or more, preferably 18 or more, from the viewpoint of the adsorption of the dispersant to the carbon material-based conductive material, and is 22 or less, preferably 20 or less, from the viewpoint of the solubility of the dispersant in an organic solvent.

[0029] The molar fraction a of the structural unit (A), the molar fraction b of the structural unit (B), and the molar fraction c of the structural unit (C) are each values ​​obtained when the sum of the molar fractions of all structural units constituting the dispersant (polymer) of the present disclosure is 1. When the dispersant of the present disclosure contains one or more structural units (D) other than the structural units (A) to (C), the sum of the molar fractions a to c and the molar fraction d of the structural unit (D) is 1.

[0030] In the dispersant of the present disclosure, the molar fraction a is 0.30 or more, preferably 0.40 or more, from the viewpoint of the solubility of the dispersant in an organic solvent and the dispersibility of a carbonaceous conductive material; and from the viewpoint of the adsorption of the dispersant to the carbonaceous conductive material and ease of synthesis, it is preferably 0.60 or less, more preferably 0.55 or less, and even more preferably 0.50 or less. Furthermore, the dispersant of the present disclosure may be a mixture of one or more dispersants selected from those having a molar fraction a of 0.30 or more. In the present disclosure, the molar fraction a can be calculated from the amount of amine compound used relative to the monomer I described below, which is used in the polymerization of the dispersant of the present disclosure.

[0031] In the dispersant of the present disclosure, the molar fraction b is preferably 0.40 or more, more preferably 0.45 or more, from the viewpoint of the adsorption of the dispersant to the carbon material-based conductive material, and is preferably 0.60 or less, more preferably 0.55 or less, and even more preferably 0.50 or less, from the viewpoint of ease of synthesis.

[0032] The ratio (b / a) of the molar fraction b to the molar fraction a is preferably 0.6 or more, more preferably 0.8 or more, and even more preferably 0.9 or more, from the viewpoint of improving the dispersibility of the carbon material-based conductive material in the conductive slurry, and is preferably 1.0 or less, more preferably 1.2 or less, and even more preferably 1.1 or less, from the viewpoint of the solubility of the dispersant in an organic solvent. The sum of the molar fraction a and the molar fraction b is preferably 0.8 or more, more preferably 0.9 or more, and even more preferably 1.0, from the viewpoint of improving the dispersibility of the carbon material-based conductive material. The molar fraction of structural units other than the structural unit (A) and the structural unit (B) is preferably 0.2 or less, more preferably 0.1 or less, and even more preferably 0, from the viewpoint of improving the dispersibility of the carbon material-based conductive material.

[0033] In the dispersant of the present disclosure, the molar fraction c is preferably 0.20 or less, more preferably 0.10 or less, even more preferably 0.05 or less, and still more preferably 0, from the viewpoint of improving the dispersibility of the carbon material-based conductive material.

[0034] In the dispersant of the present disclosure, the molar fraction d is preferably 0.20 or less, more preferably 0.10 or less, even more preferably 0.05 or less, and still more preferably 0, from the viewpoint of improving the dispersibility of the carbon material-based conductive material.

[0035] The dispersant of the present disclosure is, for example, a modified copolymer obtained by neutralizing, as necessary, an amidated copolymer of a vinyl ether monomer and maleic anhydride. From the viewpoint of adsorption to a carbonaceous conductive material, the weight-average molecular weight of the copolymer of a vinyl ether monomer and maleic anhydride before amide modification is preferably 30,000 or more, more preferably 50,000 or more, and even more preferably 150,000 or more. From the viewpoints of solubility in organic solvents, dispersibility of the carbonaceous conductive material, and low viscosity of the slurry, the weight-average molecular weight is preferably 500,000 or less, more preferably 400,000 or less, and even more preferably 350,000 or less. In the present disclosure, the weight-average molecular weight of the copolymer of a vinyl ether monomer and maleic anhydride before amide modification is a value measured by GPC (gel permeation chromatography). The detailed measurement conditions are as shown in the "Measurement of Weight-Average Molecular Weight" section in the Examples.

[0036] Examples of the monomer I that provides the structural unit (A) represented by the general formula (1) include maleic anhydride and maleic acid, but maleic anhydride, which has a structure reactive with amines, is preferred because it allows for the easy introduction of a hydrocarbon group by amidation.

[0037] As the monomer II that provides the structural unit (B) represented by the general formula (2) above, from the viewpoint of the adsorption of the dispersant to the carbon material-based conductive material, at least one selected from the group consisting of alkyl vinyl ethers having from 16 to 22 carbon atoms is preferred, such as cetyl vinyl ether, heptadecyl vinyl ether, stearyl vinyl ether, nonadecyl vinyl ether, arachidyl vinyl ether, behenyl vinyl ether, isostearyl vinyl ether, isobehenyl vinyl ether, etc. Among these, from the viewpoints of the adsorption of the dispersant to the carbon material-based conductive material, ease of synthesis of the dispersant, and ease of availability of the monomer, at least one selected from the group consisting of stearyl vinyl ether, behenyl vinyl ether, and cetyl vinyl ether, which contain a linear alkyl group, is preferred.

[0038] The dispersant of the present disclosure can be prepared, for example, by mixing monomer I and monomer II in a solvent, polymerizing the monomers by a solution polymerization method, and then polymerizing the monomers by a solution polymerization method. 1 and R is a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group. 2 and an amine compound having R 1 and R 2 is introduced. The solution containing the amide-modified copolymer thus obtained is neutralized in whole or in part with a neutralizing agent, as needed. Thereafter, if necessary, solvent substitution is performed to replace the solvent in the solution containing the amide-modified copolymer with an aqueous solvent, thereby precipitating the amide-modified copolymer and obtaining the dispersant of the present disclosure. Neutralization of the dispersant may be performed during the preparation of the dispersant composition.

[0039] Examples of solvents that can be used in synthesizing the dispersant of the present disclosure include organic solvents such as hydrocarbons (hexane, heptane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), ketones (acetone, methyl ethyl ketone, etc.), ethers (tetrahydrofuran, diethylene glycol dimethyl ether, etc.), N-methylpyrrolidone, etc. The amount of solvent is preferably 0.5 to 10 times the total amount of monomers by mass.

[0040] The polymerization initiator used in the polymerization can be a known radical polymerization initiator, such as an azo polymerization initiator, hydroperoxides, dialkyl peroxides, diacyl peroxides, or ketone peroxides. The amount of the polymerization initiator used is preferably 0.01 to 5 mol% based on the total amount of the monomer components. The polymerization reaction is preferably carried out in a nitrogen stream at a temperature range of 40 to 180°C, and the reaction time is preferably 0.5 to 20 hours. In addition, a known chain transfer agent can be used during the polymerization. Examples of the chain transfer agent include isopropyl alcohol and mercapto compounds such as mercaptoethanol.

[0041] <Dispersant Composition for Electricity Storage Device Electrode> The dispersant of the present disclosure may be supplied to the market in the form of a polymer containing the structural unit (A) and the structural unit (B) itself, or may be supplied to the market as a dispersant composition for electricity storage device electrodes (hereinafter, sometimes abbreviated as "dispersant composition") in a state in which the dispersant is dissolved in an organic solvent (hereinafter, for convenience of explanation, referred to as "organic solvent C").

[0042] The dispersant composition of the present disclosure contains the dispersant of the present disclosure, and therefore it is possible to prepare a conductive material slurry in which the carbon material-based conductive material has good dispersibility. Use of the dispersant composition of the present disclosure makes it possible to provide a conductive material slurry in which the carbon material-based conductive material has good dispersibility, and a positive electrode paste for an electricity storage device that is capable of forming a positive electrode coating film with a low resistance value.

[0043] The content of the dispersant in the dispersant composition of the present disclosure is not particularly limited, but from the viewpoint of productivity, it is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and from the viewpoint of solubility in organic solvents, it is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0044] In one aspect, the dispersant composition of the present disclosure preferably contains an organic amine soluble in organic solvent C (hereinafter also referred to as "organic amine B2" to distinguish it from the organic amine B1 used to neutralize the dispersant) from the viewpoint of the effect of reducing the viscosity of the conductive material slurry and the positive electrode paste. The organic amine B2 preferably has an SP value of 9.5 (cal / cm 3 ) 1 / 2 More than 14.0 (cal / cm 3 ) 1 / 2 The following amine compounds are preferred, and from the viewpoint of suppressing residues on the electrodes, it is preferred that the boiling point is 260° C. or less.

[0045] The SP value is defined in the theoretical development of regular solutions and is used as an index of the solubility of a compound. The SP value in the present disclosure is calculated in accordance with the Fedors calculation method, which is one of the methods for estimating the SP value from the molecular structure, and is determined in detail based on the method described in "POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, vol. 14, No. 2, 'A Method for Estimating Both the Solubility Parameters and Molar Volumes of Liquids'."

[0046] The SP value of the organic amine B2 of the present disclosure is preferably 9.5 (cal / cm) from the viewpoint of the effect of reducing the viscosity of the conductive material slurry and the positive electrode paste. 3 ) 1 / 2 More preferably, 10.5 (cal / cm 3 ) 1 / 2 More preferably, 11.0 (cal / cm 3 ) 1 / 2and preferably 14.0 (cal / cm 3 ) 1 / 2 or less, more preferably 13.5 (cal / cm 3 ) 1 / 2 More preferably, 13.0 (cal / cm 3 ) 1 / 2 The following is the result.

[0047] The boiling point of the organic amine B2 of the present disclosure is preferably 260°C or lower, but from the viewpoint of suppressing residue on the electrode, it is preferably a temperature at which the organic amine B2 volatilizes during drying in the electrode manufacturing process, and is more preferably lower than the boiling point of a solvent commonly used as a solvent for positive electrode paste, for example, more preferably lower than the boiling point of N-methylpyrrolidone (NMP) (boiling point 202°C), and from the viewpoint of reusing NMP, it is even more preferably 190°C or lower. The lower limit of the boiling point of the organic amine B2 of the present disclosure is preferably 100°C or higher, more preferably 120°C or higher, from the viewpoint of handleability.

[0048] Among the preferred specific examples of organic amine B1 described above, preferred specific examples of organic amine B2 of the present disclosure are those having an SP value of 9.5 (cal / cm), from the viewpoint of the effect of reducing the viscosity of the conductive material slurry and the positive electrode paste. 3 ) 1 / 2 More than 14.0 (cal / cm 3 ) 1 / 2 The organic amine B2 is an amine compound having a solubility parameter (SP value) of 8.85 (cal / cm) from the viewpoint of the effect of reducing the viscosity of the conductive material slurry and the positive electrode paste. 3 ) 1 / 2, boiling point -6.3℃, same below.), dimethylamine (7.80, 7℃), ethylamine (7.93, 16.6℃), dimethylbenzylamine (9.1, 180℃), methylbenzylamine (9.8, 186℃), 2-N-dibutylaminoethanol (10.0, 226℃), 1-phenylmethanamine (10.5, 184℃), N,N-diethylaminoethanol (10.7, 162℃), 2-dimethylaminoethanol (11.3, 134℃), 1-amino-2-butanol (11.9, 169℃), 2-(ethylamino)ethanol (12.0, 169℃), 2-amino-2-methyl-1-propanol ( At least one selected from the group consisting of amine compounds such as 2-dimethylaminoethanol, 2-amino-2-methyl-1-propanol, and N-methyl-2-aminoethanol (same as above: 12.2, 185°C), DL-1-amino-2-propanol (same as above: 12.4, 160°C), N-methyl-2-aminoethanol (same as above: 12.5, 175°C), 1-(2-hydroxyethyl)piperazine (same as above: 12.98, 246°C), and N-ethyldiethanolamine (same as above: 13.4, 251°C) is preferred, at least one selected from the group consisting of 2-dimethylaminoethanol, 2-amino-2-methyl-1-propanol, and N-methyl-2-aminoethanol is more preferred, and 2-amino-2-methyl-1-propanol is particularly preferred.

[0049] Organic amine B2 may be the same as organic amine B1. In that case, when preparing the dispersant composition of the present disclosure, the total amount of the organic amine as organic amine B1 and the organic amine as organic amine B2 may be added to an unneutralized dispersant. Since the added organic amine is preferentially consumed to neutralize carboxy groups, by definition, the amount of organic amine that can neutralize all carboxy groups is the amount added as organic amine B1, and the remainder is the amount added as organic amine B2.

[0050] In one or a plurality of embodiments, the content of organic amine B2 in the dispersant composition of the present disclosure is, relative to 100 parts by mass of the dispersant of the present disclosure, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, and still more preferably 30 parts by mass or more, from the viewpoint of the effect of reducing the viscosity of the conductive material slurry and the positive electrode paste; and, from the viewpoint of the solubility of the dispersant, is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, even more preferably 200 parts by mass or less, and still more preferably 150 parts by mass or less, relative to 100 parts by mass of the dispersant.

[0051] The mass ratio of the dispersant of the present disclosure to the organic amine B2 of the present disclosure (dispersant / organic amine B2) in the dispersant composition of the present disclosure is preferably 0.3 or more, more preferably 0.4 or more, even more preferably 0.5 or more, and even more preferably 0.6 or more, from the viewpoint of the solubility of the dispersant, and from the viewpoint of the effect of reducing the viscosity of the conductive material slurry and the positive electrode paste and reducing the DC resistance of the electricity storage device, it is preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and even more preferably 3 or less.

[0052] [Organic Solvent C] Examples of organic solvent C include amide-based polar organic solvents such as dimethylformamide (DMF), diethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP), ketone-based polar organic solvents such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK), and ester-based polar organic solvents such as ethyl acetate, γ-butyllactone, and ε-caprolactone. Organic solvent C is preferably N-methylpyrrolidone, which has a high solubility for the dispersant of the present disclosure, and more preferably N-methylpyrrolidone. Organic solvent C may be one of these organic solvents or a combination of two or more of them.

[0053] The dispersant composition of the present disclosure may further contain other components, such as antioxidants, antifoaming agents, preservatives, dehydrating agents, rust inhibitors, plasticizers, binders, etc., to the extent that the effects of the present disclosure are not impaired.

[0054] <Carbonaceous Material-Based Conductive Material Slurry> In one aspect, the present disclosure relates to a carbonaceous material-based conductive material slurry (hereinafter also referred to as the "conductive material slurry of the present disclosure") containing a carbonaceous material-based conductive material, a dispersant of the present disclosure, an organic solvent, and, if necessary, an organic amine B2. Preferred embodiments of the dispersant and organic amine B2 of the present disclosure in this aspect are as described above. The organic solvent in this aspect is preferably the same as the organic solvent C described above, and more preferably NMP. Because the conductive material slurry of the present disclosure contains the dispersant of the present disclosure, it has low viscosity, the dispersed particle size of the carbonaceous material-based conductive material is small, and the dispersibility of the carbonaceous material-based conductive material is good.

[0055] [Carbon Material-Based Conductive Material] In one or more embodiments, examples of the carbon material-based conductive material include carbon nanotubes (hereinafter sometimes referred to as "CNT"), carbon black, graphite, graphene, etc., and among these, at least one selected from carbon black and carbon nanotubes is preferred, and CNT is more preferred. The average diameter of the CNT that can be used as the carbon material-based conductive material is not particularly limited, but from the viewpoint of improving the dispersibility of the CNT, it is preferably 1 nm or more, more preferably 2 nm or more, and even more preferably 5 nm or more. From the viewpoint of improving the conductivity, it is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 20 nm or less. The average length of the CNT is also not particularly limited, but from the viewpoint of improving the conductivity, it is preferably 2 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and even more preferably 30 μm or more. From the viewpoint of improving the dispersibility, it is preferably 500 μm or less, more preferably 300 μm or less, even more preferably 200 μm or less, and even more preferably 120 μm or less. In this disclosure, the average diameter and average length of CNTs can be measured using a scanning electron microscope (SEM) or an atomic force microscope (AFM). Depending on the properties required for the positive electrode coating, single-walled, double-walled, or multi-walled CNTs can be used, or a mixture thereof can be used. The positive electrode coating is a film-like layer obtained by coating the electrode substrate (current collector).

[0056] (Content of Carbon Material-Based Conductive Material in Conductive Material Slurry) The content of the carbon material-based conductive material in the conductive material slurry of the present disclosure is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, from the viewpoint of improving the convenience of adjusting the concentration of the positive electrode paste, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less, from the viewpoint of imparting a viscosity to the conductive material slurry that is easy to handle.

[0057] (Content of dispersant in conductive material slurry) From the viewpoint of improving the dispersibility of the carbon material-based conductive material, the content of the dispersant in the conductive material slurry of the present disclosure is preferably 0.01 mass % or more, more preferably 0.05 mass % or more, even more preferably 0.08 mass % or more, and still more preferably 0.15 mass % or more, and from the viewpoint of high conductivity, it is preferably 2.0 mass % or less, more preferably 1.5 mass % or less, even more preferably 1.2 mass % or less, and still more preferably 1.0 mass % or less.

[0058] The content of the dispersant in the conductive material slurry of the present disclosure is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, even more preferably 5 parts by mass or more, and still more preferably 10 parts by mass or more, relative to 100 parts by mass of the carbon material-based conductive material, from the viewpoint of improving the dispersibility of the carbon material-based conductive material, and from the viewpoint of high conductivity, is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 90 parts by mass or less, and still more preferably 75 parts by mass or less.

[0059] (Content of organic amine B2 in conductive material slurry) The content of organic amine B2 in the conductive material slurry of the present disclosure is preferably 0.01 mass % or more, more preferably 0.05 mass % or more, even more preferably 0.1 mass % or more, and still more preferably 0.2 mass % or more, from the viewpoint of improving the dispersibility of the carbon material-based conductive material and reducing the resistance of the electricity storage device, and is preferably 2.0 mass % or less, more preferably 1.5 mass % or less, even more preferably 1.0 mass % or less, and still more preferably 0.8 mass % or less, from the viewpoint of high conductivity.

[0060] The content of organic amine B2 in the conductive material slurry of the present disclosure is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and still more preferably 15 parts by mass or more, relative to 100 parts by mass of the carbon material-based conductive material, from the viewpoint of improving the dispersibility of the carbon material-based conductive material and from the viewpoint of reducing the resistance of the electricity storage device, and is preferably 200 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 50 parts by mass or less, from the viewpoint of high conductivity.

[0061] (Method for producing conductive material slurry) In one or more embodiments, the conductive material slurry of the present disclosure can be prepared by mixing, in a mixer / disperser, a mixture of the dispersant composition of the present disclosure, the carbon material-based conductive material, the organic solvent C, and the organic amine B2, which is added as needed. In one or more embodiments, the conductive material slurry of the present disclosure may also be prepared by mixing, in a mixer / disperser, a mixture of the dispersant composition of the present disclosure, the carbon material-based conductive material, and the organic solvent C and the organic amine B2, which are added as needed.

[0062] Examples of the mixer / disperser include at least one selected from an ultrasonic homogenizer, a vibration mill, a jet mill, a ball mill, a bead mill, a sand mill, a roll mill, a homogenizer, a high-pressure homogenizer, an ultrasonic device, an attritor, a dissolver, and a paint shaker. It is also possible to mix some of the components constituting the conductive material slurry and then mix the mixture with the remainder, or each component may be added in multiple batches rather than all at once. The dispersant of the present disclosure may be dissolved in an organic solvent to form a dispersant composition, which is then mixed with other components such as a carbonaceous conductive material. The carbonaceous conductive material may be in a dry state or may be dispersed in a solvent. Examples of the solvent include the same organic solvent C as described above.

[0063] <Positive Electrode Paste for Electrical Storage Device> In one aspect, the present disclosure relates to a positive electrode paste for an electrical storage device (hereinafter also referred to as the "positive electrode paste of the present disclosure") comprising the dispersant of the present disclosure, a carbonaceous conductive material, a positive electrode active material, an organic solvent, and, if necessary, an organic amine B2. A preferred embodiment of the dispersant of the present disclosure in this aspect is as described above. The organic solvent in this aspect is preferably the same as the organic solvent C described above, and more preferably NMP. Because the positive electrode paste of the present disclosure contains the dispersant of the present disclosure, it is possible to form a positive electrode coating film with a low resistance value.

[0064] The positive electrode paste of the present disclosure may further include a binder. In one or more embodiments, the positive electrode paste of the present disclosure may further include a conductive material other than the carbon material-based conductive material. Examples of the conductive material other than the carbon material-based conductive material include a conductive polymer such as polyaniline.

[0065] (Positive Electrode Active Material) The positive electrode active material is not particularly limited as long as it is an inorganic compound, and for example, a compound having an olivine structure, a lithium transition metal composite oxide, etc. can be used. The compound having an olivine structure is represented by the general formula Li x M1 s Examples of lithium transition metal composite oxides include compounds represented by the formula LiPO4 (where M1 is a 3d transition metal, 0≦x≦2, 0.8≦s≦1.2). Compounds having an olivine structure may be used after being coated with amorphous carbon or the like. Examples of lithium transition metal composite oxides include lithium manganese oxides having a spinel structure, and lithium manganese oxides having a layered structure and the general formula Li x M2O 2- Examples of suitable lithium transition metal composite oxides include those represented by the formula (x, δ) where M2 is a transition metal, 0.4≦x≦1.2, and 0≦δ≦0.5. The transition metal M2 may include Co, Ni, or Mn. The lithium transition metal composite oxide may further contain one or more elements selected from Al, Fe, Cr, Ti, Zn, P, and B.

[0066] The content of the positive electrode active material in the positive electrode paste of the present disclosure is not particularly limited, as long as it can be adjusted according to the viscosity of the positive electrode paste suitable for application to a current collector. From the viewpoints of energy density and stability of the positive electrode paste, however, the content is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less.

[0067] The content of the positive electrode active material in the total solid content of the positive electrode paste of the present disclosure is not particularly limited. The content of the positive electrode active material in the total solid content of the positive electrode paste of the present disclosure may be the same as that in the total solid content of a conventionally known positive electrode paste, and is preferably 90.0 mass % or more in order to maintain a high energy density of the electricity storage device, and is preferably 99.9 mass % or less in order to ensure the conductivity and coating properties of the composite layer.

[0068] (Binder) As the binder (binder resin), polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, styrene-butadiene rubber, polyacrylonitrile, etc. can be used alone or in combination.

[0069] The content of the binder in the total solid content of the positive electrode paste of the present disclosure is preferably 0.05% by mass or more from the viewpoint of the coating properties of the composite layer and the binding property with the current collector, and is preferably 9.95% by mass or less from the viewpoint of maintaining a high energy density of the electricity storage device.

[0070] (Content of Dispersant in Positive Electrode Paste) From the viewpoint of coating film resistance, the content of the dispersant of the present disclosure in the positive electrode paste of the present disclosure is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and is preferably 2.0% by mass or less, more preferably 1.0% by mass or less.

[0071] (Content of organic amine B2 in positive electrode paste) The content of organic amine B2 of the present disclosure in the positive electrode paste of the present disclosure is preferably 0.005% by mass or more, more preferably 0.012% by mass or more, and even more preferably 0.02% by mass or more, from the viewpoint of increasing the solids concentration of the positive electrode paste and reducing the viscosity, and is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less, from the viewpoint of solubility in the solvent and stability of the positive electrode paste.

[0072] (Content of Carbonaceous Conductive Material in Positive Electrode Paste) The content of the carbonaceous conductive material in the positive electrode paste of the present disclosure is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of the conductivity of the composite layer, and is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less, from the viewpoint of maintaining a high energy density of the electricity storage device.

[0073] In one or more embodiments, the positive electrode paste of the present disclosure can be prepared by mixing and stirring a positive electrode active material, a conductive material slurry of the present disclosure, a binder, organic amine B2, and an organic solvent (additional solvent) for adjusting the solid content concentration, etc. In addition, a dispersant other than the dispersant of the present disclosure, a functional material, etc. may be added. The organic solvent (additional solvent) is preferably the organic solvent C described above, and more preferably NMP. A planetary mixer, a bead mill, a jet mill, etc. can be used for mixing and stirring these components, or these can be used in combination.

[0074] The positive electrode paste of the present disclosure can be prepared by premixing some of the components used in preparing the positive electrode paste and then mixing the premixed components with the remaining components. Alternatively, each component may be added in multiple batches rather than all at once. This reduces the mechanical load on the stirring device.

[0075] The solids concentration of the positive electrode paste of the present disclosure, the amount of positive electrode active material, the amount of binder, the amount of conductive material slurry, the amount of additive components added, and the amount of organic solvent can be adjusted depending on the viscosity of the positive electrode paste suitable for application to a current collector. From the viewpoint of drying, a small amount of organic solvent is preferable, but from the viewpoints of uniformity of the positive electrode composite layer and surface smoothness, it is preferable that the viscosity of the positive electrode paste is not too high. On the other hand, from the viewpoints of inhibiting drying and obtaining a sufficient thickness of the composite layer (positive electrode coating), it is preferable that the viscosity of the positive electrode paste is not too low.

[0076] The positive electrode paste of the present disclosure is preferably able to be adjusted to a high concentration from the viewpoint of production efficiency, but a significant increase in viscosity is undesirable from the viewpoint of workability. By adding an additive, it is possible to maintain a high concentration while maintaining a preferred viscosity range.

[0077] The conductive material slurry and the positive electrode paste of the present disclosure may each further contain other components, such as antioxidants, antifoaming agents, preservatives, dehydrating agents, rust inhibitors, plasticizers, and binders, to the extent that the effects of the present disclosure are not impaired.

[0078] (Method for Producing Positive Electrode Paste) In one or more embodiments, the method for producing a positive electrode paste of the present disclosure may include a step of mixing the carbonaceous conductive material slurry of the present disclosure, a binder, a positive electrode active material, and, if necessary, an additional organic solvent or organic amine B2. In one or more embodiments, the method for producing a positive electrode paste of the present disclosure may further include, if necessary, mixing an additional dispersant composition of the present disclosure and an additional carbonaceous conductive material. The components may be mixed in any order. In one or more embodiments, the conductive material slurry of the present disclosure, an additional organic solvent, and a binder are mixed and dispersed until homogeneous, and then the positive electrode active material is mixed and stirred until homogeneous, thereby obtaining a positive electrode paste. The order of addition of these components is not limited thereto.

[0079] <Method for manufacturing a positive electrode coating film or a positive electrode for an electricity storage device> In one aspect, the present disclosure relates to a method for manufacturing a positive electrode coating film or a positive electrode for an electricity storage device produced using the positive electrode paste of the present disclosure. The manufacturing method of this aspect includes applying the positive electrode paste of the present disclosure to a current collector, followed by drying and pressing. In this aspect, a preferred form of the positive electrode paste of the present disclosure is as described above. In the manufacturing method of the present disclosure, a positive electrode coating film or a positive electrode for an electricity storage device can be manufactured by a conventionally known method, except for using the positive electrode paste of the present disclosure.

[0080] The positive electrode coating film or the positive electrode for an electricity storage device is prepared, for example, by applying the above-described positive electrode paste to a current collector such as aluminum foil and drying the resulting film. To increase the density of the positive electrode coating film, compaction can be performed using a press. A die head, a cone reverse roll, a direct roll, a gravure roll, or the like can be used to apply the positive electrode paste. Drying after coating can be performed using heating, airflow, infrared irradiation, or a combination thereof. Drying after coating is performed at a temperature at which the organic solvent in the positive electrode paste can no longer be present in the positive electrode paste after the drying time has elapsed. The drying temperature is not particularly limited as long as it is equal to or lower than the thermal decomposition temperature of the binder resin under the drying environment (atmospheric pressure or vacuum), but is preferably equal to or higher than the boiling point of the organic solvent. The drying temperature is preferably 60°C or higher and 220°C or lower, and the drying time is preferably 10 minutes to 24 hours. The positive electrode can be pressed using a roll press or the like. After pressing, the positive electrode for an electricity storage device may be processed into a size suitable for incorporation into an electricity storage device, and then re-dried under the above conditions.

[0081] In one aspect, the present disclosure relates to an electricity storage device including a positive electrode for an electricity storage device obtained by the method for producing a positive electrode for an electricity storage device of the present disclosure, and a method for producing the same. In one or more embodiments, examples of the electricity storage device include a lithium ion secondary battery, a lithium-air secondary battery, a sodium ion battery, a sodium-sulfur secondary battery, a sodium-nickel chloride secondary battery, an organic radical battery, a zinc-air secondary battery, and an all-solid-state battery.

[0082] The method for producing an electricity storage device according to the present disclosure includes, for example, the same steps as those of known methods for producing electricity storage devices, except that the positive electrode for an electricity storage device according to the present disclosure is used as the positive electrode for an electricity storage device. The method for producing an electricity storage device according to the present disclosure includes, for example, a step of overlapping two electrodes (a positive electrode and a negative electrode) with a separator interposed therebetween and winding or stacking them into a battery shape, and a step of placing the resulting wound body or stack into a battery container or a laminate container, injecting an electrolyte into the container, and sealing the battery container or the laminate container.

[0083] The use of the polymer containing the structural unit (A) represented by the general formula (1) and the structural unit (B) represented by the general formula (2) as a dispersant is not limited to the conductive material slurry or the positive electrode paste used in the production of a positive electrode for an electrical storage device, which contains the carbon material-based conductive material and the polar solvent (organic solvent). The polymer can be used as a dispersant in various carbon material-containing dispersions containing a carbon material-based conductive material and a polar solvent (organic solvent). Examples of the carbon material-containing dispersions include negative electrode pastes, inkjet inks, and conductive inks. The polar solvent (organic solvent) contained in these carbon material-containing dispersions is preferably the organic solvent C described above. The preferred content of the carbon material-based conductive material in the carbon material-containing dispersion may be the same as that in known carbon material-containing dispersions. The preferred content of the polymer in the carbon material-containing dispersion (relative to 100 parts by mass of the carbon material-based conductive material) may be the same as that in the conductive material slurry of the present disclosure.

[0084] The present application discloses the following invention as still another aspect.

[0085] <1> A dispersant for an electrode of an electricity storage device, which is a polymer including a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), wherein the molar fraction a of the structural unit (A) relative to all structural units of the polymer is 0.30 or more: However, in the above general formula (1), R 1 is a hydrocarbon group having 1 to 14 carbon atoms which may have hydrogen or a hydroxyl group, and R 2is a linear or branched alkyl group, M is hydrogen, NH4, a metal or an organic ammonium, and in the above general formula (2), R 3 is hydrogen or a methyl group, and R 4 is a hydrocarbon group having 16 to 22 carbon atoms. <2> The dispersant for an electric storage device electrode according to <1>, wherein the molar fraction a of the structural unit (A) is preferably 0.30 or more, more preferably 0.40 or more, and preferably 0.60 or less, more preferably 0.55 or less, and even more preferably 0.50 or less. <3> The dispersant for an electric storage device electrode according to <1> or <2>, wherein the molar fraction b of the structural unit (B) is preferably 0.40 or more, more preferably 0.45 or more, and preferably 0.60 or less, more preferably 0.55 or less, and even more preferably 0.50 or less. <4> The dispersant for an electric storage device electrode according to <3>, wherein the ratio (a / b) of the molar fraction a to the molar fraction b is preferably 0.6 or more, more preferably 0.8 or more, and even more preferably 0.9 or more, and preferably 1.0 or less, more preferably 1.2 or less, and even more preferably 1.1 or less. <5> The dispersant for an electrical storage device electrode according to <3> or <4>, wherein the sum of the molar fraction a and the molar fraction b is preferably 0.8 or more, more preferably 0.9 or more, and even more preferably 1.0. <6> The dispersant for an electrical storage device electrode according to any one of <1> to <5>, wherein the molar fraction of structural units other than the structural unit (A) and the structural unit (B) is preferably 0.2 or less, more preferably 0.1 or less, and even more preferably 0. <7> The dispersant for an electrical storage device electrode according to any one of <1> to <6>, wherein the dispersant further contains a structural unit (C) derived from maleic anhydride represented by the following general formula (3), and the molar fraction c of the structural unit (C) is preferably 0.20 or less, more preferably 0.10 or less, even more preferably 0.05 or less, and even more preferably 0. <8> The dispersant for an electrical storage device electrode according to <7>, wherein the dispersant for an electrical storage device electrode comprises one or more structural units (D) other than the structural units (A) to (C), and the molar fraction d of the structural unit (D) is preferably 0.20 or less, more preferably 0.10 or less, even more preferably 0.05 or less, and still more preferably 0. <9> The dispersant composition for an electrical storage device electrode, comprising the dispersant for an electrical storage device electrode according to any one of <1> to <8> and an organic solvent. <10> The dispersant composition for an electrical storage device electrode according to <9>, wherein the content of the dispersant for an electrical storage device electrode in the dispersant composition for an electrical storage device electrode is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. <11> The dispersant composition for an electrical storage device electrode according to <9> or <10>, wherein the organic solvent is N-methylpyrrolidone. <12> The dispersant composition for an electrical storage device electrode according to any one of <9> to <11>, further comprising one or more organic amines B2 soluble in the organic solvent. <13> The SP value of the organic amine B2 is preferably 9.5 (cal / cm 3 ) 1 / 2 More preferably, 10.5 (cal / cm 3 ) 1 / 2 More preferably, 11.0 (cal / cm 3 ) 1 / 2 It is preferably 14.0 (cal / cm 3 ) 1 / 2 or less, more preferably 13.5 (cal / cm 3 ) 1 / 2 More preferably, 13.0 (cal / cm 3 ) 1 / 2<14> The dispersant composition for an electrical storage device electrode according to <12> or <13>, wherein the boiling point of the organic amine B2 is preferably 260°C or less, more preferably 202°C or less, even more preferably 190°C or less, and preferably 100°C or more, more preferably 120°C or more. <15> The dispersant composition for an electrical storage device electrode according to any one of <12> to <14>, wherein the content of the organic amine B2 is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, and preferably 300 parts by mass or less, more preferably 250 parts by mass or less, even more preferably 200 parts by mass or less, and still more preferably 150 parts by mass or less, relative to 100 parts by mass of the dispersant for an electrical storage device electrode. <16> The dispersant composition for an electrical storage device electrode according to any one of <12> to <15>, wherein the mass ratio of the dispersant for an electrical storage device electrode to the organic amine B2 (dispersant / organic amine B2) in the dispersant composition for an electrical storage device electrode is preferably 0.3 or more, more preferably 0.4 or more, even more preferably 0.5 or more, still more preferably 0.6 or more, and is preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and still more preferably 3 or less. <17> A carbonaceous conductive material slurry comprising the dispersant for an electrical storage device electrode according to any one of <1> to <8>, a carbonaceous conductive material, and an organic solvent. <18> The carbonaceous conductive material slurry according to <17>, wherein the carbonaceous conductive material is at least one selected from carbon black and carbon nanotubes. <19> The carbon material-based conductive material slurry according to <17> or <18>, wherein the content of the carbon material-based conductive material in the carbon material-based conductive material slurry is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 5% by mass or less.<20> The carbon material-based conductive material slurry according to any one of <17> to <19>, wherein the content of the dispersant for an electrical storage device electrode in the carbon material-based conductive material slurry is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.08% by mass or more, still more preferably 0.15% by mass or more, and preferably 2.0% by mass or less, more preferably 1.5% by mass or less, even more preferably 1.2% by mass or less, and still more preferably 1.0% by mass or less. <21> The carbon material-based conductive material slurry according to any one of <17> to <20>, wherein the content of the dispersant for an electrical storage device electrode in the carbon material-based conductive material slurry is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, even more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 90 parts by mass or less, and still more preferably 75 parts by mass or less, relative to 100 parts by mass of the carbon material-based conductive material. <22> The carbon material-based conductive material slurry according to any one of <17> to <21>, wherein the carbon material-based conductive material slurry contains one or more organic amines B2 soluble in the organic solvent, and the content of the organic amine B2 in the carbon material-based conductive material slurry is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, even more preferably 0.1 mass% or more, still more preferably 0.2 mass% or more, and is preferably 2.0 mass% or less, more preferably 1.5 mass% or less, even more preferably 1.0 mass% or less, and still more preferably 0.8 mass% or less. <23> The carbon material-based conductive material slurry according to any one of <17> to <22>, wherein the carbon material-based conductive material slurry contains one or more organic amines B2 soluble in the organic solvent, and the content of the organic amine B2 in the carbon material-based conductive material slurry is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, still more preferably 15 parts by mass or more, and is preferably 200 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 50 parts by mass or less, relative to 100 parts by mass of the carbon material-based conductive material.<24> A positive electrode paste for an electricity storage device, comprising the dispersant for an electricity storage device electrode according to any one of <1> to <8>, a carbon material-based conductive material, a positive electrode active material, and an organic solvent. <25> The positive electrode paste for an electricity storage device according to <24>, wherein the content of the positive electrode active material in the positive electrode paste for an electricity storage device is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less. <26> The positive electrode paste for an electricity storage device according to <24> or <25>, wherein the content of the dispersant for an electricity storage device electrode in the positive electrode paste for an electricity storage device is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and preferably 2.0% by mass or less, more preferably 1.0% by mass or less. <27> The positive electrode paste for an electricity storage device according to any one of <24> to <26>, wherein the positive electrode paste for an electricity storage device contains one or more organic amines B2 soluble in the organic solvent, and the content of the organic amine B2 in the positive electrode paste for an electricity storage device is preferably 0.005% by mass or more, more preferably 0.012% by mass or more, even more preferably 0.02% by mass or more, and is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. <28> The positive electrode paste for an electricity storage device according to any one of <24> to <27>, wherein the content of the carbon material-based conductive material in the positive electrode paste for an electricity storage device is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less. <29> A method for producing a positive electrode for an electricity storage device, comprising applying the positive electrode paste for an electricity storage device according to any one of <24> to <28> to a current collector and drying the applied paste. <30> A method for producing an electricity storage device, comprising incorporating the positive electrode for an electricity storage device obtained by the method for producing a positive electrode for an electricity storage device according to <29>.<31> A dispersant for carbon materials, which is a polymer including a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), wherein the molar fraction a of the structural unit (A) relative to all structural units of the polymer is 0.30 or more. However, in the above general formula (1), R 1 is a hydrocarbon group having 1 to 14 carbon atoms which may have hydrogen or a hydroxyl group, and R 2 is a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group, M is hydrogen, NH4, a metal or an organic ammonium, and in the above general formula (2), R 3 is hydrogen or a methyl group, and R 4 is a hydrocarbon group having 16 or more and 22 or less carbon atoms. <32> The following dispersant for carbon materials is used as a dispersant in a carbon material-containing dispersion containing a carbon material-based conductive material and a polar solvent (organic solvent). The dispersant for carbon materials is a polymer containing a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), and the molar fraction a of the structural unit (A) relative to all structural units of the polymer is 0.30 or more. However, in the above general formula (1), R 1 is a hydrocarbon group having 1 to 14 carbon atoms which may have hydrogen or a hydroxyl group, and R 2 is a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group, M is hydrogen, NH4, a metal or an organic ammonium, and in the above general formula (2), R 3 is hydrogen or a methyl group, and R 4 is a hydrocarbon group having a carbon number of 16 or more and 22 or less. <33> The use of the dispersant for a carbon material according to <32>, wherein the carbon material-containing dispersion is a negative electrode paste, an inkjet ink, or a conductive ink.

[0086] Examples and comparative examples of the present disclosure will be shown below, but the present disclosure is not limited thereto.

[0087] 1. Measurement method for each parameter [Measurement of weight-average molecular weight] The weight-average molecular weight of the copolymer before amide modification was measured by GPC. Detailed conditions are as follows. Measurement device: HLC-8320GPC (manufactured by Tosoh Corporation) Column: α-M + α-M (manufactured by Tosoh Corporation) Column temperature: 40°C Detector: Differential refractive index Eluent: N,N-dimethylformamide (DMF) solution of 60 mmol / L H3PO4 and 50 mmol / L LiBr Flow rate: 1 mL / min Standard sample used for calibration curve: Polystyrene Sample solution: DMF solution containing 0.5 wt% solids of the copolymer Amount of sample solution injected: 100 μL

[0088] [Measurement of Viscosity of Conductive Slurry] The viscosity of the conductive slurry (25°C) was measured as follows: A parallel plate PP50 was attached to an MCR302 rheometer manufactured by Anton Paar, and the shear rate was set to 0.1 s -1 From the 1000s -1 After raising it to (outbound), 1000s -1 From 0.1 seconds -1 Return to (return), and the shear rate on the return trip is 1 s -1 The viscosity was measured at 100°C, and the results are shown in Tables 1 and 2.

[0089] [Measurement of Resistance Value of Positive Electrode Coating Film] The positive electrode paste was dropped onto a polyester film and uniformly coated with a 100 μm applicator. The coated polyester film was dried at 80 ° C for 1 hour to obtain a positive electrode coating film with a thickness of 40 μm. The coating film resistance was measured at a limit voltage of 10 V using a Loresta-GP (manufactured by Mitsubishi Chemical Analytech) equipped with a PSP probe, and the results are shown in Table 1.

[0090] [Measurement of DC Resistance (DCR)] To measure DC resistance, a power storage device was fabricated using the following procedure. The positive electrode paste was applied to a 20 μm-thick Al foil (current collector) so that the positive electrode capacity was 3 mAh / cm 2The mixture was coated onto a current collector and vacuum dried at 100°C for 12 hours to produce an electrode material (positive electrode material). This positive electrode material was punched and pressed to a diameter of 13 mm to obtain an electrode (positive electrode). A 19 mm diameter separator and a 15 mm diameter, 0.5 mm thick coin-shaped lithium metal were placed on the positive electrode to produce a 2032-type coin cell (a test half cell). The electrolyte used was 1M LiPF6 EC / DEC (volume ratio = 3 / 7).

[0091] The test half-cell was placed in a 30°C thermostatic chamber and subjected to a three-cycle charge-discharge test under the following conditions: (Charge-discharge conditions) 30°C, 0.2C, charge 4.45V CC / CV 1 / 10C cutoff, discharge CC 3.0V cutoff. Next, the battery was charged at 0.2C for 2.5 hours, and the direct current resistance (DCR) was calculated from the voltage drop over 10 seconds during discharge from 0.2C to 8C. The results are shown in Table 1.

[0092] 2. Synthesis of Dispersant, and Preparation of Dispersant Composition and Conductive Slurry [Example 1] (Synthesis of Dispersant) 49.7 g of maleic anhydride (MAn) (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) and 242.7 g of methyl isobutyl ketone (MIBK) (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) were charged into a 1 L four-necked glass separable flask, stirred for 0.5 hours under a nitrogen atmosphere, and heated to 100°C. Then, 150.3 g of stearyl vinyl ether (SVE) (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) dissolved in 225.5 g of MIBK and Perloyl L (aliphatic diacyl peroxide, molecular formula: C 24 H 46 A solution of 100% methyl ether (O4, molecular weight: 398.63, manufactured by NOF Corporation) in 7.1 g of MIBK was added dropwise to the flask via a separate line over one hour. The mixture was then aged at 100°C for two hours to complete the polymerization reaction. The solvent was then evaporated to obtain a stearyl vinyl ether / maleic anhydride copolymer with a weight-average molecular weight of 300,000.

[0093] 42.2 g of the stearyl vinyl ether / maleic anhydride copolymer and 450.0 g of methyl isobutyl ketone (MIBK) (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) were placed in a 1 L four-neck separable glass flask and stirred for a certain period of time (0.5 hours) under a nitrogen atmosphere. Then, 7.8 g of iso-butylamine (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was added to the flask at room temperature. The reaction solution in the flask was then heated to around 60°C and maintained for 2 hours to obtain a polymer solution. The solvent was then evaporated from the polymer solution to obtain the dispersant of Example 1, and infrared absorption spectroscopy (IR) was used to confirm that the target compound had been obtained. This was then mixed with N-methyl-2-pyrrolidone (NMP) to obtain a dispersant composition B1 containing 20.0% by mass of the dispersant of Example 1. The dispersant of Example 1 and N-methyl-2-pyrrolidone (NMP) were mixed by stirring at room temperature for 5 hours at a rotation speed of 200 rpm. After standing for 1 hour from the preparation of the dispersant composition, the appearance of Dispersant Composition B1 (25°C) was visually uniform and transparent.

[0094] (Preparation of Conductive Material Slurry) 1.5 parts by mass of multi-walled carbon nanotubes (manufactured by LG Chem, BT-1003M, average diameter 12.5 nm, length 10 to 70 μm (catalog value)), 1.5 parts by mass of dispersant composition B1, and 97.0 parts by mass of NMP were mixed to obtain a crude dispersion. The crude dispersion was filled into a high-pressure homogenizer (manufactured by Biryu Co., Ltd., product name "BERYU MINI") equipped with a multi-stage pressure control device (multi-stage pressure reducer) that applies back pressure during dispersion, and a dispersion treatment was carried out at a pressure of 120 MPa. Specifically, shear force was applied to the crude dispersion while applying back pressure to disperse the multi-walled carbon nanotubes (CNTs), thereby obtaining conductive material slurry E1. The conductive material slurry E1 had a CNT content of 1.5% by mass, and a dispersant content of 0.3% by mass (20 parts by mass relative to 100 parts by mass of CNT), with the remainder being NMP. The dispersion treatment was carried out by circulating the dispersion by discharging it from the high-pressure homogenizer and injecting it back into the high-pressure homogenizer, and this circulation was carried out 20 times. The discharging and injecting rate of the dispersion was 45 g / min. The viscosity of the conductive material slurry E1 at a temperature of 25°C was 11.4 mPa s.

[0095] [Examples 2 to 7, Comparative Examples 1 and 3] The dispersants of Examples 2 to 7 and Comparative Examples 1 and 3 listed in Table 1 below were synthesized by changing the type (see below) or the amount of the amine compound used for amidating the stearyl vinyl ether / maleic anhydride copolymer in the synthesis of the dispersant. [Amine Compound] Example 2: Tetradecylamine Example 3: Hexylamine Example 4 and Comparative Example 3: Iso-butylamine Example 5: Ethylamine Example 6: 1-amino-2-butanol Example 7: Diethanolamine Comparative Example 1: Stearylamine

[0096] Next, dispersant compositions B2 to B7, B9, and B11 were prepared in the same manner as in Example 1, each containing 20.0 mass% of the dispersant of Examples 2 to 7 and Comparative Examples 1 and 3, with the remainder being NMP. Using these compositions, conductive material slurries E2 to E7, E9, and E11 containing the dispersant of Examples 2 to 7 and Comparative Examples 1 and 3, respectively, were prepared in the same manner as in Example 1. The CNT content, dispersant content, and NMP content in the conductive material slurries E2 to E7, E9, and E11 were the same as those in the conductive material slurry E1. The appearance of each of the dispersant compositions B2 to B7 after standing for one hour from the preparation was uniform and transparent to the naked eye. On the other hand, the appearance of each of the dispersant compositions B9 and B11 after standing for one hour from the preparation was cloudy to the naked eye. The viscosities of the conductive material slurries E2 to E7, E9, and E11 at 25°C are shown in Table 1.

[0097] [Example 8] The dispersant of Example 1, 2-amino-2-methyl-1-propanol (AMP) as the organic amine B1, and N-methyl-2-pyrrolidone (NMP) were mixed to obtain a dispersant composition B8 containing 20.0 mass% of the dispersant of Example 8 (a neutralized product of the dispersant of Example 1). The amount of AMP added was an amount sufficient to neutralize all of the carboxy groups in the dispersant of Example 1. The components were mixed at room temperature for 5 hours by stirring at a rotation speed of 200 rpm. After allowing to stand for 1 hour after the preparation of dispersant composition B8, the appearance of dispersant composition B1 (25°C) was visually confirmed to be uniform and transparent. Using dispersant composition B8, a conductive material slurry E8 containing the dispersant of Example 8 was prepared in the same manner as in [Example 1]. In the conductive material slurry E8, the content of CNT was 1.5 mass %, the content of the dispersant of Example 8 was 0.3 mass %, which was 20 parts by mass relative to 100 parts by mass of CNT, and the remainder was NMP.

[0098] [Comparative Example 2] 34.05 g of methyl vinyl ether / maleic anhydride copolymer (Gantrez AN119 manufactured by Ashland, weight average molecular weight 130,000) and 450.0 g of tetrahydrofuran (THF) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were placed in a 1 L four-neck glass separable flask and stirred for a certain period of time (0.5 hours) under a nitrogen atmosphere. Then, 15.95 g of iso-butylamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to the flask at room temperature. Next, the reaction solution in the flask was heated to around 60 ° C and maintained for 2 hours to obtain a polymer solution. The solvent was then evaporated from the polymer solution to obtain the dispersant of Comparative Example 2.

[0099] Next, a dispersant composition B10 containing 20.0 mass% of the dispersant of Comparative Example 2 was prepared in the same manner as in Example 1, and a conductive material slurry E10 was prepared using the same in the same manner as in Example 1. The CNT content, dispersant content, and NMP content in the conductive material slurry E10 were the same as those in the conductive material slurry E1. After allowing the dispersant composition B10 to stand for 1 hour after its preparation, the appearance was found to be cloudy when visually observed. The viscosity of the conductive material slurry E10 at a temperature of 25°C is shown in Table 1.

[0100]

[0101] As shown in Table 1, the viscosities of the conductive slurries containing the dispersants of Examples 1 to 8 were significantly lower than the viscosities of the conductive slurries containing the dispersants of Comparative Examples 1 to 3.

[0102] 3. Preparation of Positive Electrode Paste 2.06 g of conductive material slurry E1, 1.03 g of NMP, and 1.9 g of PVDF (8%) NMP solution (KF Polymer L#7208, manufactured by Kureha Corporation) were weighed into a 50 ml sample bottle and uniformly stirred with a spatula. Then, 12 g of LiCoO2 (CellSeed, manufactured by Nippon Chemical Industry Co., Ltd.) was added as the positive electrode active material, and the mixture was again stirred with a spatula until uniform. The mixture was further stirred for 5 minutes with a planetary centrifugal mixer (AR-100, manufactured by Thinky Corporation) to obtain positive electrode paste D1. The solid content (mass%) of positive electrode paste D1 was 71.7% by mass, and the mass ratio of the positive electrode active material, binder (PVDF), conductive material (CNT), and dispersant was 98.45:1.25:0.25:0.05 (solid content equivalent). The total solid content of the positive electrode paste D1 is the total mass of the dispersant, the positive electrode active material, the conductive material, and the binder contained in the positive electrode paste D1.

[0103] Positive electrode pastes D2 to D11 were prepared in the same manner as the positive electrode paste D1, except that conductive material slurries E2 to E11 were used instead of the conductive material slurry E1.

[0104] Positive electrode coatings were prepared using positive electrode pastes D1 to D11 according to the method described above in "Measurement of Resistance Values ​​of Positive Electrode Coatings," and the coating resistances were measured. The results are shown in Table 1. As shown in Table 1, the coating resistances of the positive electrode coatings formed using positive electrode pastes D1 to D8 containing the dispersants of the examples were values ​​less than 100 Ω cm, which were sufficiently low. On the other hand, the coating resistances of the positive electrode coatings formed using positive electrode pastes D9 to D11 containing the dispersants of Comparative Examples 1 to 3 were each too high to be measured.

[0105] 4. Preparation of a positive electrode for an electricity storage device 2.6 g of the conductive material slurry E1 and acetylene black (acetylene black Li-400 manufactured by Denka, primary particle diameter 48 nm, specific surface area 39 m), which is an additional carbon material-based conductive material, were mixed. 20.24 g of PVDF (1.0 g / g (catalog value)), 0.04 g of additional dispersant composition B1 (the same dispersant composition used to prepare conductive material slurry E1), and 3.9 g of an NMP solution of PVDF (8% solids content, KF polymer L#7208, manufactured by Kureha Corporation, binder solution) were weighed into a 50 ml sample bottle and uniformly stirred with a spatula. Then, 15 g of LCO (lithium cobalt oxide, manufactured by Beijing Dangsheng Co., Ltd., "GSL-5D") as a positive electrode active material and 2.4 g of NMP as an additional solvent were added, and the mixture was again stirred with a spatula until uniform. The mixture was further stirred for 10 minutes with a planetary centrifugal mixer (AR-100, manufactured by Thinky Corporation) to obtain positive electrode paste D31. The mass ratio of the positive electrode active material, binder (PVDF), conductive material (carbon nanotubes), conductive material (acetylene black), and dispersant (the dispersant of Example 1) in Positive Electrode Paste D31 was 96.2:1.95:0.25:1.5:0.1 (solid content equivalent), and the solid content (mass %) of Positive Electrode Paste D31 was 65 mass %. The total solid content of Positive Electrode Paste D31 is the total mass of the dispersant, positive electrode active material, conductive material, and binder contained in Positive Electrode Paste D31. Using this Positive Electrode Paste D31, an electricity storage device was produced according to the above-mentioned "Measurement of Direct Current Resistance (DCR)", and the direct current resistance (DCR) was measured. The results are shown in Table 1.

[0106] As shown in Table 1, the DC resistance of the electricity storage device including the positive electrode coating film produced using the positive electrode paste D31 containing the dispersant of Example 1 was 15 Ω or less, which was a sufficiently low value.

[0107] [Preparation of Dispersant Composition B12 and Conductive Slurry E12 Comprising Organic Amine B2] The dispersant of Example 1 was mixed with 2-amino-2-methyl-1-propanol (AMP) and N-methyl-2-pyrrolidone (NMP) as organic amine B1 and organic amine B2 to prepare Dispersant Composition B12, which contained 20.0 mass% of the dispersant of Example 8 (neutralized product of the dispersant of Example 1) and 30 parts by mass of organic amine B2 relative to 100 parts by mass of the dispersant, for a mass ratio (dispersant / organic amine B2) of 3. The remainder was NMP.

[0108] Conductive slurry E12 was prepared using dispersant composition B12 in the same manner as in Example 1 above, and the viscosity of conductive slurry E12 was measured, with the results shown in Table 2. In conductive slurry E12, the CNT content was 1.5 mass %, the dispersant content was 0.3 mass % (20 mass parts relative to 100 mass parts of CNT), the organic amine B2 content was 0.09 mass % (6 mass parts relative to 100 mass parts of CNT), and the remainder was NMP.

[0109]

[0110] The viscosity of the conductive slurry E12 containing the organic amine B2 is lower than that of the conductive slurry E8. Therefore, it is understood that when the conductive slurry contains the organic amine B2, the viscosity can be reduced.

[0111] The dispersant of the present disclosure enables preparation of a conductive material slurry with good dispersibility of a carbon material-based conductive material, thereby enabling the production of a low-viscosity conductive material slurry and a positive electrode paste with high productivity. Furthermore, the use of the dispersant of the present disclosure enables the production of a low-resistance positive electrode for an electricity storage device and an electricity storage device with high productivity.

Claims

1. A dispersant for an electrode of an electricity storage device, which is a polymer comprising a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), wherein the molar fraction a of the structural unit (A) relative to all structural units of the polymer is 0.30 or more. In the above general formula (1), R 1 is a hydrocarbon group having 1 to 14 carbon atoms which may have hydrogen or a hydroxyl group, R 2 is a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group, M is hydrogen, NH4, a metal or an organic ammonium, and in the above general formula (2), R 3 is hydrogen or a methyl group, R 4 is a hydrocarbon group having 16 or more and 22 or less carbon atoms.

2. The above R 1 Or R 2 2 . The dispersant for an electrical storage device electrode according to claim 1 , wherein the hydrocarbon group having 1 or more and 14 or less carbon atoms is a linear or branched alkyl group.

3. The dispersant for an electrical storage device electrode according to claim 1 or 2, wherein the molar fraction a of the structural unit (A) is 0.50 or less.

4. A dispersant composition for an electric storage device electrode, comprising the dispersant for an electric storage device electrode according to any one of claims 1 to 3 and an organic solvent.

5. The dispersant composition for a storage device electrode according to claim 4, wherein the content of the dispersant for a storage device electrode in the dispersant composition for a storage device electrode is 10 mass % or more and 50 mass % or less.

6. The dispersant composition for a storage device electrode according to claim 4 or 5, wherein the organic solvent is N-methylpyrrolidone.

7. A dispersant composition for a storage device electrode according to any one of claims 4 to 6, further comprising one or more organic amines B2 soluble in the organic solvent.

8. The SP value of the organic amine B2 is 9.5 (cal / cm 3 ) 1 / 2 More than 14.0 (cal / cm 3 ) 1 / 2 The dispersant composition for an electrical storage device electrode according to claim 7 , having a boiling point of 260° C. or lower.

9. The dispersant composition for a storage device electrode according to claim 7 or 8, wherein the content of the organic amine B2 is 10 parts by mass or more and 300 parts by mass or less relative to 100 parts by mass of the dispersant for a storage device electrode.

10. A carbonaceous conductive material slurry comprising the dispersant for an electric storage device electrode according to any one of claims 1 to 3, a carbonaceous conductive material, and an organic solvent.

11. The carbon material-based conductive material slurry according to claim 10, wherein the carbon material-based conductive material is at least one material selected from the group consisting of carbon black and carbon nanotubes.

12. A positive electrode paste for an electricity storage device, comprising the dispersant for an electricity storage device electrode according to any one of claims 1 to 3, a carbon material-based conductive material, a positive electrode active material, and an organic solvent.

13. A method for producing a positive electrode for an electricity storage device, comprising applying the positive electrode paste for an electricity storage device according to claim 12 to a current collector and drying the applied paste.

14. A method for producing an electricity storage device, comprising incorporating a positive electrode for an electricity storage device obtained by the method for producing a positive electrode for an electricity storage device according to claim 13.

15. A dispersant for carbon materials, which is a polymer comprising a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), wherein the molar fraction a of the structural unit (A) relative to all structural units of the polymer is 0.30 or more. In the above general formula (1), R 1 is a hydrocarbon group having 1 to 14 carbon atoms which may have hydrogen or a hydroxyl group, R 2 is a hydrocarbon group having 1 to 14 carbon atoms which may have a hydroxyl group, M is hydrogen, NH4, a metal or an organic ammonium, and in the above general formula (2), R 3 is hydrogen or a methyl group, R 4 is a hydrocarbon group having 16 or more and 22 or less carbon atoms.

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