JP2014194927A - Mixture slurry and production method thereof, and electrode and battery using the mixture slurry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixture slurry excellent in coating aptitude while using a fine particle active material, and a method for manufacturing a battery with reduced electrode internal resistance.SOLUTION: A method for producing a mixture slurry for a secondary battery electrode includes a first step of dispersing an active material into a solvent, and a second step of adding a conductive carbon material to be mixed and kneaded or dispersed. The method also includes adding a binder simultaneously with the conductive carbon material in the second step or a third step of, subsequent to the second step, adding a binder to be mixed/dissolved and kneaded or dispersed. By the method, a mixture slurry excellent in battery performance can be obtained.

Description

  The present invention relates to a mixture slurry used for production of a battery electrode, a method for producing the same, an electrode using the same, and a battery. More specifically, the present invention relates to a mixture slurry used for producing an electrode for a lithium ion secondary battery, a method for producing the same, an electrode using the same, and a battery.

  In recent years, small portable electronic devices such as digital cameras and mobile phones have been widely used. These electronic devices have always been required to minimize the volume and reduce the weight, and the batteries to be mounted are also required to be small, light, and have a large capacity. Also, in large-sized secondary batteries for automobiles and the like, it is desired to realize a large non-aqueous electrolyte secondary battery instead of a conventional lead-acid battery.

  In order to meet such demands, lithium ion secondary batteries are being actively developed. As an electrode of a lithium ion secondary battery, a positive electrode in which a composite material composed of a positive electrode active material containing lithium ions, a conductive carbon material, a binder, and the like is fixed to the surface of a current collector of metal foil, and A negative electrode is used in which a mixture of a negative electrode active material from which lithium ions can be inserted and removed, a conductive additive, a binder, and the like is fixed to the surface of a current collector of a metal foil.

  As the positive electrode active material, lithium transition metal composite oxides such as lithium cobaltate, lithium manganate, lithium nickelate, and lithium iron phosphate are used, but these are poor in conductivity and cannot be used alone. Sufficient battery performance cannot be obtained. Therefore, attempts have been made to improve the conductivity and reduce the internal resistance of the electrode by adding a carbon material having good electron conductivity as a conductive additive.

  However, in order to achieve the recent reduction in size and increase in capacity, further improvement in conductivity is required. In particular, lithium iron phosphate having an olivine structure has a problem of low conductivity, and has been developed with an emphasis on how to reduce the particle size.

  However, although the electrical conductivity of the primary particles is improved by miniaturization, the finer the primary particles, the higher the surface energy, so that they easily aggregate and form strong secondary particles. Further, when the active material is well agglomerated, the specific surface area increases, the contact with the electrolyte increases, and the ionic resistance corresponding to the ease of lithium ion entry and exit decreases. In general, the lower the ionic resistance, the higher the battery performance such as cycle characteristics and rate characteristics. Therefore, in order to reduce the ionic resistance, it is very important to solve the aggregation of the secondary particles of the active material and to disperse / stabilize it.

On the other hand, the dispersion state of the conductive carbon material greatly affects the conductivity. In general, the conductive carbon material aggregates primary particles to form larger secondary particles. However, if the aggregation is too much, there is a problem that the electron conduction path is cut to increase the electronic resistance. In particular, since acetylene black maintains conductivity by being present as a chain structure or agglomerated structure structure in which primary particles are coalesced, the structure structure is cut by mechanical stress due to kneading, and the electronic resistance is remarkably high. Become. The higher the electronic resistance, the lower the battery performance such as cycle characteristics and rate characteristics.
On the other hand, when the conductive carbon material contains coarse particles of several tens of μm or more, the electronic resistance in the vicinity of the conductive carbon material becomes extremely low, and charge / discharge occurs preferentially over the surroundings. Therefore, there has been a problem that local deterioration is promoted, and as a result, the entire battery is deteriorated.

  As a conventional method for producing a positive electrode mixture slurry for a lithium ion secondary battery, a method in which an active material, a conductive carbon material, a binder, and a solvent are mixed and dispersed together has been used (Patent Documents). 1, 2). In this manufacturing method, since the active material and the conductive carbon material are dispersed at the same time, if the kneading time is short, the decrease in the conductivity of the conductive carbon material can be suppressed. If the kneading time rises and the kneading time is long, the aggregation of the active material can be solved, but there is a problem that the electronic resistance of the conductive carbon material increases.

  Further, for example, there is a production method in which a conductive carbon material, a binder, and a solvent are mixed, and then an active material is added and kneaded (Patent Document 3). In this manufacturing method, the conductive carbon material can be uniformly dispersed, but there is a problem that the aggregation of the active material is difficult to be solved.

  Further, for example, after dispersing a specific dispersant and an active material in a solvent, a mixture slurry produced by mixing a carbon material as a conductive auxiliary agent or a binder component as necessary is prepared. A method for improving the electrode and battery performance by use is disclosed (Patent Document 4). However, the order of adding each component is not particularly limited, and in the examples, since the binder is added before the addition of the conductive carbon material, the binder component easily covers the active material, and the ion There is a concern that resistance will rise. Moreover, it can be said that the particle diameter of the dispersed active material is large and the aggregation of the active material is not solved.

  In addition, for example, after the active material, the conductive carbon material, and the binder are separately mixed in the solvent, the mixture is mixed at once, or the active material liquid and the conductive carbon liquid are mixed, and then the binder liquid is mixed. A method is also mentioned (patent document 5). In this method, three components having different compatibility with the solvent are separately mixed with the solvent to produce a uniform mixture slurry without aggregates, thereby improving coating properties, adhesiveness, and surface condition. Is. However, there is no description about the degree of secondary aggregation dissolution and dispersion stability of each substance, and furthermore, in the examples, peeling and indentation of the composite coating film remain, and it is predicted that the dispersion is insufficient. The

  Also, for example, a first step of stirring the mixture of the active material and the binder while shearing, a second step of stirring the mixture of the conductive carbon material and the binder without shearing, and mixing them. The manufacturing method which consists of the 3rd process to perform is also mentioned (patent document 6). According to this manufacturing method, the effect of increasing the output by bringing the active material subdivided into primary particles into contact with the conductive carbon material while maintaining the chain shape is shown. However, when the primary particle diameter of the active material is 200 nm or less, it is difficult to maintain a stable slurry that is dispersed to the primary particle level only by shearing and does not reagglomerate. In addition, since the active material and the binder are previously dispersed only, there is a concern that the binding component easily covers the surface of the active material and the ionic resistance increases.

JP-A-7-29605 JP 2000-123879 JP-A-9-213309 WO2010 / 013786 JP 2010-27403 JP 2010-238388

  The present invention suppresses the dispersion of the active material and the conductive carbon material and the accompanying storage instability, poor coating properties, poor conductivity, and increase in ionic resistance, thereby reducing the internal resistance in the electrode. Another object of the present invention is to provide a secondary battery excellent in adhesion between the current collector and the composite layer, rate characteristics excellent in binding properties between the active material and the conductive carbon material, and cycle characteristics.

  The inventors of the present invention have prepared a slurry for a secondary battery electrode comprising a first step of dispersing an active material in a solvent and a second step of adding, mixing, kneading or dispersing a conductive carbon material. In the production method, a binder is added at the same time as the conductive carbon material in the second step, or is added, mixed, dissolved, kneaded or dispersed after the second step. It has been found that a composite slurry excellent in battery performance can be obtained by the method for producing a composite slurry for a secondary battery electrode characterized by including a step.

  An embodiment of the present invention is a method for producing a slurry for a secondary battery electrode, wherein a conductive carbon material dispersion in which a conductive carbon material is previously dispersed in a solvent is used.

  In addition, an embodiment of the present invention is a method for producing a slurry for a secondary battery electrode, characterized by using a binder solution or dispersion obtained by dissolving or dispersing a binder in a solvent in advance. .

  In addition, an embodiment of the present invention is a method for producing a slurry for a secondary battery electrode, wherein a mixed powder in which a conductive carbon material and a binder are mixed in advance is used.

  Moreover, the embodiment of the present invention is the method for producing a slurry for a secondary battery electrode, wherein the active material has a dispersed particle diameter of 10 μm or less in the first step.

  In addition, an embodiment of the present invention is the method for producing a slurry for a secondary battery electrode that is dispersed using a media type disperser in the first step.

  In addition, an embodiment of the present invention is the above-described method for producing a secondary battery electrode composite slurry, which is further dispersed together with a dispersant in the first step.

Further, in an embodiment of the present invention, the active material is a positive electrode active material, has a BET specific surface area of ^{2 to} 40 m ² / g, a primary particle diameter of 30 to 500 nm, and is coated with conductive carbon. It is a manufacturing method of the said mixture slurry for secondary battery electrodes which is the olivine type | mold lithium phosphate particle shown by 1).
General formula (1): LiFe _1-x M _x PO ₄ (0 ≦ x ≦ 1)
(In the formula, M represents at least one metal element selected from the group consisting of Mn, Co, Ni and V.)

In another embodiment of the present invention, the active material is a negative electrode active material, and the secondary battery electrode is a spinel type lithium titanate particle having a BET specific surface area of ^{2 to} 40 m ² / g and a primary particle diameter of 30 nm to 1 μm. This is a method for producing a composite slurry.

  Moreover, the embodiment of the present invention is a mixture slurry for a secondary battery electrode produced by the production method.

  Moreover, the embodiment of this invention is an electrode for secondary batteries formed by apply | coating the said mixture slurry to a base material.

  An embodiment of the present invention is a secondary battery comprising the electrode.

  According to a preferred embodiment of the present invention, the active material is uniformly and stably dispersed in the composite material layer in a state imparted with good conductivity by the conductive carbon material. Since an electrode with excellent adhesion to the material layer and binding property between the active material and the conductive auxiliary agent can be obtained, the charge / discharge efficiency of the secondary battery using this electrode is promoted by reducing the internal resistance of the electrode. The battery performance can be improved comprehensively.

It is explanatory drawing which shows the mixture slurry manufacturing process of Example 1, 5, 7-12, 17, 18. It is explanatory drawing which shows the compound-material slurry manufacturing process of Example 2, 13, and 14. FIG. It is explanatory drawing which shows the compound-material slurry manufacturing process of Example 3, 6, and 15. FIG. It is explanatory drawing which shows the compound-material slurry manufacturing process of Example 4, 16. It is explanatory drawing which shows the compound-material slurry manufacturing process of Comparative Examples 1-5. It is explanatory drawing which shows the compound-material slurry manufacturing process of the comparative examples 6 and 7. FIG. 10 is an explanatory view showing a mixed material slurry production process of Comparative Example 8. FIG. 10 is an explanatory view showing a mixed material slurry production process of Comparative Example 9. FIG. 10 is an explanatory view showing a mixed material slurry production process of Comparative Example 10. FIG.

<Positive electrode active material>
Although it does not specifically limit as a positive electrode active material, When using for a lithium ion secondary battery, metal compounds, such as a metal oxide which can dope or intercalate lithium ion, a metal sulfide, and a conductive polymer, etc. Can be used. Examples thereof include transition metal oxides such as Fe, Co, Ni, and Mn, composite oxides with lithium, and inorganic compounds such as transition metal sulfides. Specifically, transition metal oxide powders such as MnO, V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , layered structure lithium nickelate, lithium cobaltate, lithium manganate, spinel structure lithium manganate, etc. Examples thereof include composite oxide powders of lithium and transition metals, lithium iron phosphate materials that are phosphate compounds having an olivine structure, and transition metal sulfide powders such as TiS ₂ and FeS. In addition, conductive polymers such as polyaniline, polyacetylene, polypyrrole, and polythiophene can also be used. Moreover, you may mix and use said inorganic compound and organic compound.

Of the above active materials, lithium nickelate, cobaltate, lithium manganate with a layered structure, composite oxides of lithium and transition metals such as spinel-type lithium manganate, or lithium iron phosphate with an olivine structure A composite phosphorous oxide of lithium and a transition metal can be preferably used. In particular, it is preferable to use lithium metal phosphate particles represented by the general formula (1) coated with conductive carbon.
General formula (1): LiFe _1-x M _x PO ₄ (0 ≦ x ≦ 1)
(In the formula, M represents at least one metal element selected from the group consisting of Mn, Co, Ni and V.)
Specific examples include LiFePO ₄ , LiMnPO ₄ , LiFe _0.5 Mn _0.5 PO _{4 and the} like, but are not particularly limited within the range of the above general formula.

  The conductive carbon for coating the lithium phosphate metal particles is not particularly limited as long as it is a carbon material having conductivity, but is preferably a layered one in which at least one layer of conductive carbon having high crystallinity is formed. is there. Specifically, it is preferable that the graphite layer can be observed by a TEM image.

The lithium metal phosphate particles coated with the conductive carbon have an average primary particle size of 30 to 500 nm, more preferably 50 to 250 nm, and a BET specific surface area of ² to 40 m ² / g, more preferably 5 to 30 m ^2. A material having a relatively small particle diameter of / g is used. Thereby, the reaction area of an active material can be increased.

On the other hand, the negative electrode active material is not particularly limited. However, when used in a lithium secondary battery, metal Li that can be doped or intercalated with lithium ions, or an alloy thereof, tin alloy, silicon alloy negative electrode, Li _x Fe Amorphous carbonaceous materials such as metal oxides such as ₂ O ₃ , Li _X WO ₂ , Li ₄ Ti ₅ O ₁₂ , conductive polymers such as polyacetylene and poly-p-phenylene, soft carbon and hard carbon, Artificial graphite such as highly graphitized carbon material, or carbonaceous powder such as natural graphite, mesophase carbon, resin-fired carbon material, air-growth carbon fiber, carbon fiber, or other carbon-based material is used.

In the present invention, spinel type lithium titanate particles are preferably used as the negative electrode active material. Specific examples include Li ₄ Ti ₅ O ₁₂ . The lithium titanate particles have an average primary particle diameter of 30 nm to 1 μm, more preferably 50 to 800 nm, and a BET specific surface area of ² to 40 m ² / g, more preferably 5 to 30 m ² / g. Use small material. Thereby, the reaction area of an active material can be increased.

  In the present invention, the average particle diameter of primary particles is an average value of values measured by observing with an enlarged image (for example, 20,000 to 100,000 million times) of a scanning electron microscope (SEM). Indicates. Specifically, 20 particles are arbitrarily selected from the SEM image of the active material particle powder, and the average value of the major axis and the minor axis thereof.

<Conductive carbon material>
The conductive carbon material in the present invention is not particularly limited as long as it is a conductive carbon material. For example, carbon black such as acetylene black, furnace black, ketjen black, graphite, carbon nanotube, carbon fiber In addition, fullerenes and the like can be used alone or in combination of two or more. From the viewpoint of conductivity, availability, and cost, it is preferable to use carbon black. An oxidized carbon material can also be used.

  Carbon black is a furnace black produced by continuously pyrolyzing a gas or liquid raw material in a reactor, especially ketjen black using ethylene heavy oil as a raw material. Channel black that has been rapidly cooled and precipitated, thermal black obtained by periodically repeating combustion and thermal decomposition using a gas as a raw material, and particularly various types such as acetylene black using an acetylene gas as a raw material alone or 2 More than one type can be used in combination. Moreover, the carbon material by which the oxidation process normally performed can also be used.

  Carbon black used as the conductive carbon material can be oxidized carbon. The oxidation treatment of carbon is performed by treating the carbon with a high temperature in the air or by treating it with nitric acid, nitrogen dioxide, ozone, etc., for example, such as phenol group, quinone group, carboxyl group, carbonyl group. This is a treatment for directly introducing (covalently bonding) an oxygen-containing polar functional group to the carbon surface, and is generally performed to improve the dispersibility of carbon. However, the greater the amount of functional groups introduced, the lower the conductivity of the carbon, so the use of carbon that has not been oxidized is preferred.

  Examples of commercially available carbon black include furnace black manufactured by Tokai Carbon Co., Ltd. such as Toka Black # 4300, # 4400, # 4500, and # 5500; , And 5000 ULTRA, etc., Conductex SC ULTRA, Conductex 975 ULTRA, etc., PUER BLACK100, 115, 205 and other Colombian furnace blacks, # 2350, # 2400B, # 2600B, # 3030B, # 3230B, # 3230B, # 3350B, # 3350 # 3400B, # 5400B, etc. Furnace Black, MONARCH1400, 1300, 900, VulcanXC-7 Furnace Black from Cabot, such as R and BlackPearls2000, Furnace Black from TIMCAL, such as Ensaco 250G, Ensaco 260G, Ensaco 350G, and SuperP-Li, Ketjen Black from Akzo, such as Ketjen Black EC-300J, and EC-600JD, And acetylene black by Denki Kagaku Kogyo Co., Ltd., such as Denka Black, Denka Black HS-100, FX-35, etc. are mentioned, However, It is not limited to these.

<Dispersant>
The dispersant in the present invention is not particularly limited as long as it can disperse the active material well in the dispersion medium, but at least one selected from the group consisting of acidic functional groups, basic functional groups, and salts thereof. It is preferably an ionic resin type dispersant having a functional group, a nonionic resin type dispersant having no ionic functional group, an organic dye derivative, an anthraquinone derivative, an acridone derivative, or a triazine derivative. One type of these dispersants may be used, or a plurality of types of dispersants may be used in combination.

<A. Ionic resin type dispersant>
Examples of the resin dispersant include an anionic dispersant, a cationic dispersant, and an amphoteric dispersant. These are in the form of a polymer having at least one functional group selected from the group consisting of an acidic functional group, a basic functional group and a hydroxyl group, or a neutralized product of the polymer, and a solvent for the electrode-forming resin composition It can be used more suitably when an aqueous solvent is used.

  The hydrophobic part of the resin-type dispersant is a main adsorption part to the active material, and the hydrophilic part containing at least one functional group selected from the group consisting of an acidic functional group, a basic functional group and a hydroxyl group is It plays a function of dissolving or dispersing the neutralized product in an aqueous liquid medium. And, it is considered that the dispersion state in the active material aqueous liquid medium can be kept stable by charge repulsion.

<A-1. Anionic dispersant>
The anionic dispersant is not particularly limited, and examples thereof include polyvinylidene fluoride resins having acidic functional groups, polyvinyl resins having acidic functional groups, polyester resins having acidic functional groups, and other commercially available acidic functional groups. Examples thereof include a resin having a group. Examples of the acidic functional group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group.
It preferably has at least one of carboxylic acid or sulfonic acid as an anionic site, an acid value of 100 to 600 mgKOH / g, a hydroxyl value of 0 to 400 mgKOH / g, and a weight average molecular weight of 5000 or more.

  The anionic dispersant having sulfonic acid is not particularly limited as long as it is a resin having sulfonic acid. For example, a formalin condensate of aromatic sulfonic acid can be used. A formalin condensate of aromatic sulfonic acid is, for example, a product obtained by condensing benzenesulfonic acid, alkylbenzenesulfonic acid, naphthalenesulfonic acid (or an alkali metal salt thereof) with formalin.

Examples of the anionic dispersant include an ethylenically unsaturated monomer having an aromatic ring (a1), an ethylenically unsaturated monomer having a carboxyl group (a2), and an ethylenic group other than (a1) and (a2). A resin type dispersant obtained by copolymerization with the unsaturated monomer (a3) can also be used. Here, the monomer (a1) is an optional component.
The ratio of the ethylenically unsaturated monomer constituting the copolymer in the anionic dispersant is such that (a1) is 10 to 10% when the total of the monomers (a1) to (a3) is 100% by weight. 80% by weight, (a2) is preferably 20 to 75% by weight, and (a3) is preferably 0 to 70% by weight.
More preferably, (a1) is 10 to 60% by weight, (a2) is 40 to 75% by weight, and (a3) is 0 to 50% by weight.

  The ethylenically unsaturated monomer (a1) having an aromatic ring is not particularly limited as long as it is a monomer having an aromatic ring, but styrene, α-methylstyrene or benzyl (meth) acrylate can be exemplified. .

  The ethylenically unsaturated monomer (a2) having a carboxyl group is not particularly limited as long as it is a monomer having a carboxyl group, but maleic acid, fumaric acid, itaconic acid, citraconic acid, or alkyl or alkenyl thereof. Monoester, phthalic acid β- (meth) acryloxyethyl monoester, isophthalic acid β- (meth) acryloxyethyl monoester, terephthalic acid β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acrylic Examples include loxyethyl monoester, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid and the like. In particular, methacrylic acid and acrylic acid are preferable.

  Examples of the other monomer (a3) other than (a1) to (a2) include alkyl (meth) acrylates and alkylene glycol (meth) acrylates as (meth) acrylate compounds.

  An anionic dispersant is produced by polymerizing or condensing a monomer having a carboxyl group or a sulfonic acid group, and the composition ratio of the monomer having an anionic functional group in the whole molecule of the anionic dispersant is determined by acidity. In terms of value, the following is preferable. That is, the acid value of the anionic dispersant (A) used is preferably in the range of 100 mgKOH / g to 600 mgKOH / g, and more preferably in the range of 300 mgKOH / g to 600 mgKOH / g.

If the acid value of the anionic dispersant is lower than the above range, the dispersion stability of the dispersion tends to decrease and the viscosity tends to increase. On the other hand, when the acid value is higher than the above range, the adhesion of the anionic dispersant to the pigment surface is lowered, and the storage stability of the dispersion tends to be lowered.
The acid value is a value obtained by converting the acid value (mg KOH / g) measured in accordance with the potentiometric titration method of JIS K 0070 into a solid content.

<A-2. Cationic dispersant>
The cationic dispersant has at least one of an aliphatic amine or an aromatic amine as a cationic site, has an amine value of 110 to 1000 mgKOH / g, a hydroxyl value of 0 to 400 mgKOH / g, and a weight average molecular weight. It is preferable that it is a resin type dispersing agent which is 5000 or more.

  The cationic dispersant having an aliphatic amine or an aromatic amine is not particularly limited as long as it is a resin having an aliphatic amine or an aromatic amine. For example, a monomer having an aliphatic amino group or an aromatic amino group Is preferably obtained by polymerizing an ethylenically unsaturated monomer (a2) having an aliphatic amino group or an aromatic amino group. One type of monomer having an aliphatic amino group or aromatic amino group may be used, or a plurality of types may be used in combination.

  Moreover, as a cationic dispersing agent in this invention, the ethylenically unsaturated monomer (b1) which has an aromatic ring, the ethylenically unsaturated monomer (b2) which has an aliphatic amino group or an aromatic amino group, , (B1) and a resin type dispersant obtained by copolymerization with an ethylenically unsaturated monomer (b3) other than (b2) can be used. Here, the monomer (b1) or (b3) is an optional component.

The ratio of the ethylenically unsaturated monomer constituting the copolymer in the cationic dispersant is such that (b1) is 0 to 0 when the total of the monomers (b1) to (b3) is 100% by weight. It is preferable that 30% by weight, (b2) is 30 to 80% by weight, and (b3) is 0 to 70% by weight.
More preferably, (b1) is 0 to 30% by weight, (b2) is 50 to 80% by weight, and (b3) is 0 to 50% by weight.

  Although it does not specifically limit as an ethylenically unsaturated monomer (b1) which has an aromatic ring, The same thing as what was illustrated by the monomer (a1) is mentioned.

  The ethylenically unsaturated monomer (b2) having an aliphatic amino group or an aromatic amino group is not particularly limited as long as it is a monomer having an aliphatic amino group or an aromatic amino group. For example, as a monomer having one ethylenically unsaturated group in one molecule, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methylethylaminoethyl (meth) acrylate, N , N-dimethylaminopropyl (meth) acrylate, allylamine, examples of the monomer having two ethylenically unsaturated groups in one molecule include diallylamine, diallylmethylamine and the like, and aromatic amino groups Aminostyrene, dimethylaminostyrene, diethylaminos It can be exemplified Len like.

  Although it does not specifically limit as other monomers (b3) other than said (b1)-(b2), The same thing as what was illustrated by the monomer (a3) is mentioned.

  The cationic dispersant is produced by polymerizing or condensing a monomer having an amino group, and the composition ratio of the monomer having a cationic functional group in the entire molecule of the cationic dispersant is expressed by an amine value. The following is preferred. That is, the amine value of the cationic dispersant used is preferably in the range of 110 mgKOH / g or more and less than 1000 mgKOH / g, and more preferably in the range of 250 mgKOH / g or more and less than 1000 mgKOH / g.

When the amine value of the cationic dispersant is lower than the above range, the dispersion stability of the dispersion is lowered and the viscosity tends to increase. On the other hand, when the amine value is higher than the above range, the adhesion of the cationic dispersant to the pigment surface is lowered, and the storage stability of the dispersion tends to be lowered.
The amine value is expressed in mg of potassium hydroxide equivalent to perchloric acid required to neutralize all basic nitrogen contained in 1 g of the sample. The measurement method is a value obtained by converting the solid content obtained by the potentiometric titration method described in JIS K 7237 (1995).

<A-3. Amphoteric dispersant>
As the amphoteric dispersant, an ethylenically unsaturated monomer having an aromatic ring (c1), an ethylenically unsaturated monomer having a carboxyl group (c2), an ethylenically unsaturated monomer having an amino group ( c3) and an essential component of the copolymer and a neutralized product of the copolymer are preferable.
The ratio of the monomers constituting the copolymer in the amphoteric dispersant (C) is such that (c1) is 5 to 70% when the total of the monomers (c1) to (c4) is 100% by weight. %, (C2) is 15 to 60% by weight, (c3) is 1 to 80% by weight, and (c4) is 0 to 79% by weight.
Preferably, (c1): 20 to 70% by weight, (c2): 15 to 45% by weight, (c3): 1 to 70% by weight, and (c4): 0 to 50% by weight.
More preferably, (c1): 30 to 70% by weight, (c2): 15 to 35% by weight, (c3): 1 to 40% by weight, (c4): 0 to 40% by weight.

  Although it does not specifically limit as an ethylenically unsaturated monomer (c1) which has an aromatic ring, The same thing as what was illustrated by the monomer (a1) is mentioned.

  The ethylenically unsaturated compound (c2) having a carboxyl group is a maleic acid, fumaric acid, itaconic acid, citraconic acid, or an alkyl or alkenyl monoester thereof, phthalic acid β- (meta ) Acryloxyethyl monoester, isophthalic acid β- (meth) acryloxyethyl monoester, terephthalic acid β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acryloxyethyl monoester, acrylic acid, methacrylic acid Examples thereof include acid, crotonic acid, and cinnamic acid. In particular, methacrylic acid and acrylic acid are preferable.

  Examples of the ethylenically unsaturated monomer (c3) having an amino group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methylethylaminoethyl (meth) acrylate, dimethylaminostyrene, and diethylaminostyrene. .

  Although it does not specifically limit as other monomers (c4) other than said (c1)-(c3), The same thing as what was illustrated by the monomer (a3) is mentioned.

  The hydroxyl value of the resin-type dispersant is preferably 0 mgKOH / g or more and 400 mgKOH / g or less, and more preferably 0 mgKOH / g or more and 250 mgKOH / g or less. When the hydroxyl value is 400 mgKOH / g or more, the interaction between molecules in the aqueous medium becomes strong, and the viscosity of the dispersant solution becomes higher than necessary, which may deteriorate the dispersibility of the active material.

<B. Nonionic dispersant>
Nonionic resins include resins that do not have an ionic functional group. In particular,
Polyvinyl acetal, polyvinyl butyral, polyvinyl alcohol, polyalkylene glycol-modified acrylic resin, polyalkylene oxide, polyvinyl ether, polyvinyl caprolactam, polyvinyl pyrrolidone, vinyl acetate-vinyl pyrrolidone copolymer, vinyl pyrrolidone-methacrylamide-vinyl imidazole copolymer And vinyl pyrrolidone resins such as alkylated vinyl pyrrolidone-1-butene copolymer, lignin, pectin, gelatin, xanthan gum, welan gum, succinoglycan, cellulosic resins, chitins, chitosans, starch and the like. However, it is not particularly limited to these.

  The weight average molecular weight of the resin-type dispersant is preferably 5000 or more. More preferably, it is 30000 or more. Moreover, the upper limit is preferably 1500,000 or less, and more preferably 800,000 or less. When the weight average molecular weight is less than 5,000, there is a possibility of causing poor dispersion of the carbon material that is the electrode active material or the conductive assistant. When the weight average molecular weight is less than 30,000, it may elute into the electrolyte and cause deterioration of the battery performance. is there.

  A neutralizing agent can also be added to the resin-type dispersant. By neutralization, the salt of the acidic functional group and the basic functional group is easily dissociated in an aqueous medium, and more easily charged. Therefore, the surface of the conductive carbon and the surface of the positive and negative electrode active materials on which the neutralized anionic dispersant is adsorbed are charged, and dispersibility is further improved by the repulsion.

<C. Organic dye derivatives, anthraquinone derivatives, acridone derivatives, triazine derivatives>
As the dispersant, organic dye derivatives, anthraquinone derivatives, acridone derivatives, and triazine derivatives (hereinafter sometimes abbreviated as various derivatives) can also be suitably used. Various derivatives having at least one functional group selected from the group consisting of an acidic functional group, a basic functional group, and a hydroxyl group can be more suitably used when a non-aqueous solvent is used as a solvent for the resin composition for electrode formation. These various derivatives are also described in the following documents.
Reference 1: JP 2010-061934 A

  These dispersants are considered to exhibit a dispersing effect when an organic dye moiety or anthraquinone, acridone, or triazine moiety acts on the surface of the active material (for example, adsorption). Then, at least one functional group selected from the group consisting of an acidic functional group, a basic functional group, and a hydroxyl group possessed by the dispersant acting on the surface of the active material material is polarized or dissociated, thereby causing an electrical interaction (repulsive action). It is considered that the dispersion state of the active material in the non-aqueous liquid medium can be kept stable.

<C-1. Various derivatives having acidic functional groups>
As various derivatives having an acidic functional group, a triazine derivative represented by the following general formula (11) or an organic dye derivative represented by the general formula (14) is preferable.

  Formula (11)

Ｘ₁は−ＮＨ−、−Ｏ−、−ＣＯＮＨ−、−ＳＯ₂ＮＨ−、−ＣＨ₂ＮＨ−、−ＣＨ₂ＮＨＣＯＣＨ₂ＮＨ−または−Ｘ₃−Ｙ−Ｘ₄−を表し、Ｘ₂及びＸ₄はそれぞれ独立に−ＮＨ−または−Ｏ−を表し、Ｘ₃は−ＣＯＮＨ−、−ＳＯ₂ＮＨ−、−ＣＨ₂ＮＨ−、−ＮＨＣＯ−または−ＮＨＳＯ₂−を表し、
Ｙは炭素数１〜２０で構成された、置換基を有してもよいアルキレン基、置換基を有してもよいアルケニレン基または置換基を有してもよいアリーレン基を表し、
Ｚは−ＳＯ₃Ｍまたは−ＣＯＯＭ、または−Ｐ（Ｏ）（−ＯＭ）₂または−Ｏ−Ｐ（Ｏ）（−ＯＭ）₂を表し、Ｍは１〜３価のカチオンの一当量を表し、
Ｒ₁は有機色素残基、置換基を有していてもよい複素環残基、置換基を有していてもよい芳香族環残基または下記一般式（１２）で表される基を表し、
Ｑは−Ｏ−Ｒ₂、−ＮＨ−Ｒ₂、ハロゲン基、−Ｘ₁−Ｒ₁または−Ｘ₂−Ｙ−Ｚを表し、Ｒ₂は水素原子、置換基を有してもよいアルキル基または置換基を有してもよいアルケニル基を表す。
ｎは、１〜４の整数を表す。

X ₁ is -NH -, - O -, - CONH -, - SO 2 NH -, - CH 2 NH -, - CH 2 NHCOCH 2 NH- or -X ₃ -Y-X ₄ - represents, X ₂ and X ₄ each independently represent a -NH- or -O-, X ₃ is _{-CONH -, - SO 2 NH -} , - CH 2 NH -, - NHCO- or -NHSO ₂ - represents,
Y represents a C1-C20 alkylene group which may have a substituent, an alkenylene group which may have a substituent or an arylene group which may have a substituent,
Z represents —SO ₃ M or —COOM, or —P (O) (— OM) ₂ or —O—P (O) (— OM) ₂ , and M represents one equivalent of a 1 to 3 valent cation. ,
R ₁ represents an organic dye residue, a heterocyclic residue which may have a substituent, an aromatic ring residue which may have a substituent, or a group represented by the following general formula (12). ,
Q represents —O—R ₂ , —NH—R ₂ , a halogen group, —X ₁ —R ₁ or —X ₂ —YZ, and R ₂ represents a hydrogen atom or an alkyl group which may have a substituent. Or the alkenyl group which may have a substituent is represented.
n represents an integer of 1 to 4.

  Formula (12)

Ｘ₅は−ＮＨ−または−Ｏ−を表し、Ｘ₆及びＸ₇はそれぞれ独立に−ＮＨ−、−Ｏ−、−ＣＯＮＨ−、−ＳＯ₂ＮＨ−、−ＣＨ₂ＮＨ−または−ＣＨ₂ＮＨＣＯＣＨ₂ＮＨ−を表し、
Ｒ₃及びＲ₄はそれぞれ独立に、有機色素残基、置換基を有していてもよい複素環残基、置換基を有していてもよい芳香族環残基または−Ｙ−Ｚを表し、Ｙ及びＺは一般式（１１）と同義である。

X ₅ represents -NH- or -O-, X ₆ and X ₇ each independently -NH -, - O -, - CONH -, - SO 2 NH -, - CH 2 NH- or -CH ₂ NHCOCH ₂ represents NH-
R ₃ and R ₄ each independently represents an organic dye residue, an optionally substituted heterocyclic residue, an optionally substituted aromatic ring residue, or —YZ. , Y and Z have the same meanings as in the general formula (11).

Examples of the organic dye residue represented by R _{1 in the} general formula (11) and R ₃ and R ₄ in the general formula (12) include, for example, diketopyrrolopyrrole dyes, azo dyes such as azo, disazo and polyazo, Phthalocyanine dyes, diaminodianthraquinones, anthrapyrimidines, flavantrons, anthanthrone, indanthrone, pyranthrone, violanthrone and other anthraquinone dyes, quinacridone dyes, dioxazine dyes, perinone dyes, perylene dyes, thioindigo dyes , Isoindoline dyes, isoindolinone dyes, quinophthalone dyes, selenium dyes, metal complex dyes, and the like. In particular, in order to increase the effect of suppressing the short circuit of the battery due to metal, it is preferable to use an organic dye residue that is not a metal complex dye, among which an azo dye, a diketopyrrolopyrrole dye, a metal-free phthalocyanine dye, Use of a quinacridone dye or a dioxazine dye is preferable because of its excellent dispersibility.

Examples of the heterocyclic residue and aromatic ring residue represented by R _{1 in the} general formula (11) and R ₃ and R ₄ in the general formula (12) include thiophene, furan, pyridine, pyrazole, pyrrole, imidazole. , Isoindoline, isoindolinone, benzimidazolone, benzthiazole, benztriazole, indole, quinoline, carbazole, acridine, benzene, naphthalene, anthracene, fluorene, phenanthrene, anthraquinone and the like. In particular, the use of a heterocyclic residue containing at least one of S, N, and O heteroatoms is preferable because of excellent dispersibility.

  Y in the general formula (11) and the general formula (12) represents an alkylene group, an alkenylene group or an arylene group which may have a substituent having 20 or less carbon atoms, and preferably an optionally substituted phenylene. Group, biphenylene group, naphthylene group or alkylene group which may have a side chain having 10 or less carbon atoms.

The alkyl group or alkenyl group which may have a substituent represented by R ₂ contained in Q in the general formula (11) preferably has 20 or less carbon atoms, more preferably 10 carbon atoms. The alkyl group which may have the following side chains is mentioned. An alkyl group or alkenyl group having a substituent is a group in which a hydrogen atom of an alkyl group or an alkenyl group is substituted with a halogen group such as a fluorine atom, a chlorine atom or a bromine atom, a hydroxyl group or a mercapto group.

In the formula of the general formula (11), M represents one equivalent of a monovalent to trivalent cation, for example, a hydrogen atom (proton), a metal cation, or a quaternary ammonium cation. Further, when two or more Ms are included in the dispersant structure, M may be only one of a proton, a metal cation, and a quaternary ammonium cation, or a combination thereof.
Examples of the metal include lithium, sodium, potassium, calcium, barium, magnesium, aluminum, nickel, and cobalt.

The quaternary ammonium cation is a single compound having a structure represented by the general formula (13) or a mixture.
Formula (13)

Ｒ₅、Ｒ₆、Ｒ₇、Ｒ₈は、水素、置換基を有してもよいアルキル基、置換基を有してもよいアルケニル基、または置換基を有してもよいアリール基のいずれかを表す。

R ₅ , R ₆ , R ₇ and R ₈ are any of hydrogen, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an aryl group which may have a substituent. Represents

R ₅ , R ₆ , R ₇ and R ₈ in the general formula (13) may be the same or different. Moreover, when R < ₅ >, R < ₆ >, R < ₇ >, R < ₈ > has a carbon atom, carbon number is 1-40, Preferably it is 1-30, More preferably, it is 1-20. If the carbon number exceeds 40, the conductivity of the electrode may be reduced.

  General formula (14)

Ｘ₈は直接結合、−ＮＨ−、−Ｏ−、−ＣＯＮＨ−、−ＳＯ₂ＮＨ−、−ＣＨ₂ＮＨ−、−ＣＨ₂ＮＨＣＯＣＨ₂ＮＨ−または−Ｘ₉−Ｙ−または−Ｘ₉−Ｙ−Ｘ₁₀−を表し、Ｘ₉は−ＣＯＮＨ−、−ＳＯ₂ＮＨ−、−ＣＨ₂ＮＨ−、−ＮＨＣＯ−または−ＮＨＳＯ₂−を表し、Ｘ₁₀は−ＮＨ−または−Ｏ−を表し、Ｙは炭素数１〜２０で構成された、置換基を有してもよいアルキレン基、置換基を有してもよいアルケニレン基または置換基を有してもよいアリーレン基を表し、
Ｚは−ＳＯ₃Ｍまたは−ＣＯＯＭ、または−Ｐ（Ｏ）（−ＯＭ）₂、または−Ｏ−Ｐ（Ｏ）（−ＯＭ）₂を表し、Ｍは１〜３価のカチオンの一当量を表し、
Ｒ₉は有機色素残基を表し、ｎは１〜４の整数を表す。

X ₈ is a direct bond, -NH -, - O -, - CONH -, - SO 2 NH -, - CH 2 NH -, - CH 2 NHCOCH 2 NH- or -X ₉ -Y- or -X ₉ -Y -X ₁₀ - represents, X ₉ is _{-CONH -, - SO 2 NH -} , - CH 2 NH -, - NHCO- or -NHSO ₂ - represents, X ₁₀ represents -NH- or -O-, Y represents a C1-C20 alkylene group which may have a substituent, an alkenylene group which may have a substituent or an arylene group which may have a substituent,
Z represents —SO ₃ M or —COOM, or —P (O) (— OM) ₂ , or —O—P (O) (— OM) ₂ , and M represents one equivalent of a 1 to 3 valent cation. Represent,
R ₉ represents an organic dye residue, and n represents an integer of 1 to 4.

Examples of the organic dye residue represented by R ₉ in the general formula (14) include diketopyrrolopyrrole dyes, azo dyes such as azo, disazo, and polyazo, phthalocyanine dyes, diaminodianthraquinone, anthrapyrimidine, and flavantrons. , Antanthrone, Indanthrone, Pyrantron, Biolantron, etc. Anthraquinone dyes, quinacridone dyes, dioxazine dyes, perinone dyes, perylene dyes, thioindigo dyes, isoindoline dyes, isoindolinone dyes, quinophthalone System dyes, selenium dyes, metal complex dyes, and the like. The organic dye residue represented by R ₉ includes a light yellow anthraquinone residue that is not generally called a dye. In particular, in order to increase the effect of suppressing the short circuit of the battery due to metal, it is preferable to use an organic dye residue that is not a metal complex dye, among which an azo dye, a diketopyrrolopyrrole dye, a metal-free phthalocyanine dye, Use of a quinacridone dye or a dioxazine dye is preferable because of its excellent dispersibility.

M in the formula of the general formula (14) represents one equivalent of a monovalent to trivalent cation, for example, a hydrogen atom (proton), a metal cation, or a quaternary ammonium cation. Further, when two or more Ms are included in the dispersant structure, M may be only one of a proton, a metal cation, and a quaternary ammonium cation, or a combination thereof.
Examples of the metal include lithium, sodium, potassium, calcium, barium, magnesium, aluminum, nickel, and cobalt.

<C-2. Various derivatives having basic functional groups>
As various derivatives having a basic functional group, it is preferable to use a triazine derivative represented by the following general formula (21) or an organic dye derivative represented by the general formula (26).

  Formula (21)

Ｘ₁は、−ＮＨ−、−Ｏ−、−ＣＯＮＨ−、−ＳＯ₂ＮＨ−、−ＣＨ₂ＮＨ−、−ＣＨ₂ＮＨＣＯＣＨ₂ＮＨ−または−Ｘ₂−Ｙ−Ｘ₃−を表し、Ｘ₂は、−ＮＨ−、−Ｏ−、−ＣＯＮＨ−、−ＳＯ₂ＮＨ−、−ＣＨ₂ＮＨ−、−ＮＨＣＯ−または−ＮＨＳＯ₂−を表し、Ｘ₃はそれぞれ独立に−ＮＨ−または、−Ｏ−を表し、Ｙは炭素数１〜２０で構成された、置換基を有してもよいアルキレン基、置換基を有してもよいアルケニレン基または、置換基を有してもよいアリーレン基を表す。
Ｐは、一般式（２２）、（２３）または、一般式(２４)のいずれかで示される置換基を表す。
Ｑは、−Ｏ−Ｒ₂、−ＮＨ−Ｒ₂、ハロゲン基、−Ｘ₁−Ｒ₁または、一般式（２２）、（２３）もしくは、一般式(２４)のいずれかで示される置換基を表す。
Ｒ₂は、水素原子、置換基を有してもよいアルキル基または、置換基を有してもよいアルケニル基もしくは、置換基を有してもよいアリール基を表す。

X ₁ is, -NH -, - O -, - CONH -, - SO 2 NH -, - CH 2 NH -, - CH 2 NHCOCH 2 NH- or -X ₂ -Y-X ₃ - represents, X ₂ is, -NH -, - O -, - CONH -, - SO 2 NH -, - CH 2 NH -, - NHCO- or -NHSO ₂ - represents, X ₃ each independently -NH- or, -O -Y represents an alkylene group which may have a substituent, an alkenylene group which may have a substituent, or an arylene group which may have a substituent, which is composed of 1 to 20 carbon atoms. Represent.
P represents a substituent represented by any one of the general formulas (22), (23) and the general formula (24).
Q represents —O—R ₂ , —NH—R ₂ , a halogen group, —X ₁ —R _1, or a substituent represented by any one of the general formulas (22), (23), or (24). Represents.
R ₂ represents a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, or an aryl group that may have a substituent.

General formula (22)

Formula (23)

General formula (24)

Ｘ₄は、直接結合、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂ＮＨＣＯＣＨ₂−、−ＣＨ₂ＮＨＣＯＮＨＣＨ₂−、−ＣＨ₂−または、−Ｘ₅−Ｙ−Ｘ₆−を表す。Ｘ₅は、−ＮＨ−または、−Ｏ−を表し、Ｘ₆は、直接結合、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂ＮＨＣＯＣＨ₂−、−ＣＨ₂ＮＨＣＯＮＨＣＨ₂−または、−ＣＨ₂−を表す。Ｙは炭素数１〜２０で構成された、置換基を有してもよいアルキレン基、置換基を有してもよいアルケニレン基または、置換基を有してもよいアリーレン基を表す。
ｖは、１〜１０の整数を表す。
Ｒ₃ 、Ｒ₄はそれぞれ独立に、水素原子、置換されていてもよいアルキル基、置換されていてもよいアルケニル基、置換されていてもよいアリール基、またはＲ₃ 、Ｒ₄とで一体となって更なる窒素、酸素または硫黄原子を含む置換されていてもよい複素環残基を表す。とりわけ、水素原子であることが、電池内での金属析出を抑える効果が高いと思われ好ましい。
Ｒ₅ 、Ｒ₆ 、Ｒ₇ 、Ｒ₈は、それぞれ独立に、水素原子、置換されていてもよいアルキル基、置換されていてもよいアルケニル基または置換されていてもよいアリール基を表す。
Ｒ₉は、置換されていてもよいアルキル基、置換されていてもよいアルケニル基または置換されていてもよいアリール基を表す。
ｎは、１〜４の整数を表す。
Ｒ₁は有機色素残基、置換基を有していてもよい複素環残基、置換基を有していてもよい芳香族環残基または下記一般式（２５）で示される基を表す。

X ₄ is a direct _{bond, -SO 2 -, - CO -} , - CH 2 NHCOCH 2 -, - CH 2 NHCONHCH 2 -, - CH 2 - or, -X ₅ -Y-X ₆ - represents a. X ₅ is -NH- or represents -O-, X ₆ represents a direct _{bond, -SO 2 -, - CO -} , - CH 2 NHCOCH 2 -, - CH 2 NHCONHCH 2 - or -CH ₂ - Represents. Y represents an alkylene group which may have a substituent, an alkenylene group which may have a substituent, or an arylene group which may have a substituent, having 1 to 20 carbon atoms.
v represents an integer of 1 to 10.
R ₃ and R ₄ are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted aryl group, or R ₃ and R ₄ together. Represents an optionally substituted heterocyclic residue containing additional nitrogen, oxygen or sulfur atoms. In particular, a hydrogen atom is preferable because it is considered that the effect of suppressing metal deposition in the battery is high.
R ₅ , R ₆ , R ₇ and R ₈ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group or an optionally substituted aryl group.
R ₉ represents an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted aryl group.
n represents an integer of 1 to 4.
R ₁ represents an organic dye residue, a heterocyclic residue which may have a substituent, an aromatic ring residue which may have a substituent, or a group represented by the following general formula (25).

  Formula (25)

Ｔは、−Ｘ₈−Ｒ₁₀または、Ｗ₁を表し、Ｕは、−Ｘ₉−Ｒ₁₁または、Ｗ₂を表す。
Ｗ₁およびＷ₂は、それぞれ独立に−Ｏ−Ｒ₂、−ＮＨ−Ｒ₂、ハロゲン基または、一般式（２２）、（２３）もしくは、一般式(２４)のいずれかで示される置換基を表す。
Ｒ₂は、水素原子、置換基を有してもよいアルキル基または、置換基を有してもよいアルケニル基もしくは、置換基を有してもよいアリール基を表す。
Ｘ₇は−ＮＨ−または−Ｏ−を表し、Ｘ₈およびＸ₉は、それぞれ独立に−ＮＨ−、−Ｏ−、−ＣＯＮＨ−、−ＳＯ₂ＮＨ−、−ＣＨ₂ＮＨ−または−ＣＨ₂ＮＨＣＯＣＨ₂ＮＨ−を表す。
Ｙは炭素数１〜２０で構成された、置換基を有してもよいアルキレン基、置換基を有してもよいアルケニレン基または、置換基を有してもよいアリーレン基を示す。
Ｒ₁₀およびＲ₁₁はそれぞれ独立に、有機色素残基、置換基を有していてもよい複素環残基、置換基を有していてもよい芳香族環残基を表す。

T is -X ₈ -R ₁₀ or represents W _1, U represents -X ₉ -R ₁₁ or W _2.
W ₁ and W ₂ are each independently —O—R ₂ , —NH—R ₂ , a halogen group, or a substituent represented by any one of the general formulas (22), (23), or (24). Represents.
R ₂ represents a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, or an aryl group that may have a substituent.
X ₇ represents an -NH- or -O-, X ₈ and X ₉ are each independently -NH -, - O -, - CONH -, - SO 2 NH -, - CH 2 NH- or -CH ₂ NHCOCH represents a ₂ NH-.
Y represents an alkylene group which may have a substituent, an alkenylene group which may have a substituent, or an arylene group which may have a substituent, which has 1 to 20 carbon atoms.
R ₁₀ and R ₁₁ each independently represents an organic dye residue, a heterocyclic residue which may have a substituent, or an aromatic ring residue which may have a substituent.

Examples of the organic dye residue represented by R _{1 in the} general formula (21) and R ₁₀ and R ₁₁ in the general formula (25) include azo dyes such as diketopyrrolopyrrole dyes, azo, disazo, and polyazo. Anthraquinone dyes such as phthalocyanine dyes, diaminodianthraquinones, anthrapyrimidines, flavantrons, anthanthrones, indantrons, pyrantrons, violanthrones, quinacridone dyes, dioxazine dyes, perinone dyes, perylene dyes, thioindigo dyes And dyes, isoindoline dyes, isoindolinone dyes, quinophthalone dyes, selenium dyes, metal complex dyes, and the like. In particular, in order to enhance the effect of suppressing the short circuit of the battery due to metal, it is preferable to use an organic dye residue that is not a metal complex dye.

Examples of the heterocyclic residue and aromatic ring residue represented by R _{1 in the} general formula (21) and R ₁₀ and R ₁₁ in the general formula (25) include thiophene, furan, pyridine, pyrazine, triazine, Examples include pyrazole, pyrrole, imidazole, isoindoline, isoindolinone, benzimidazolone, benzthiazole, benztriazole, indole, quinoline, carbazole, acridine, benzene, naphthalene, anthracene, fluorene, phenanthrene, anthraquinone, and acridone. These heterocyclic residues and aromatic ring residues are alkyl groups (methyl group, ethyl group, butyl group, etc.), amino groups, alkylamino groups (dimethylamino group, diethylamino group, dibutylamino group, etc.), nitro groups. Hydroxyl group, alkoxy group (methoxy group, ethoxy group, butoxy group, etc.), halogen (chlorine, bromine, fluorine, etc.), phenyl group (alkyl group, amino group, alkylamino group, nitro group, hydroxyl group, alkoxy group, halogen, etc.) And a substituent such as a phenylamino group (which may be substituted with an alkyl group, amino group, alkylamino group, nitro group, hydroxyl group, alkoxy group, halogen, etc.) May be.

Y in the general formula (21) and the general formula (25) represents an alkylene group, an alkenylene group or an arylene group which may have a substituent having 20 or less carbon atoms, and preferably an optionally substituted phenylene. Group, biphenylene group, naphthylene group or alkylene group which may have a side chain having 10 or less carbon atoms.
General formula (26)

Ｚは、下記一般式（２７）、（２８）または、一般式（２９）で示される群から選ばれる少なくとも１つのものである。ｎは、１〜４の整数を表す。
一般式（２７）

Z is at least one selected from the group represented by the following general formula (27), (28) or general formula (29). n represents an integer of 1 to 4.
Formula (27)

Formula (28)

一般式（２９）

Formula (29)

Ｘ₄は、直接結合、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂ＮＨＣＯＣＨ₂−、−ＣＨ₂ＮＨＣＯＮＨＣＨ₂−、−ＣＨ₂−または、−Ｘ₅−Ｙ−Ｘ₆−を表す。Ｘ₅は、−ＮＨ−または、−Ｏ−を表し、Ｘ₆は、直接結合、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂ＮＨＣＯＣＨ₂−、−ＣＨ₂ＮＨＣＯＮＨＣＨ₂−または、−ＣＨ₂−を表す。Ｙは炭素数１〜２０で構成された、置換基を有してもよいアルキレン基、置換基を有してもよいアルケニレン基または、置換基を有してもよいアリーレン基を表す。
ｖは、１〜１０の整数を表す。
Ｒ₃ 、Ｒ₄はそれぞれ独立に、水素原子、置換されていてもよいアルキル基、置換されていてもよいアルケニル基、置換されていてもよいフェニル基、またはＲ₃ 、Ｒ₄とで一体となって更なる窒素、酸素または硫黄原子を含む置換されていてもよい複素環残基を表す。とりわけ、水素原子であることが、電池内での金属析出を抑える効果が高いと思われ好ましい。
Ｒ₅ 、Ｒ₆ 、Ｒ₇ 、Ｒ₈は、それぞれ独立に、水素原子、置換されていてもよいアルキル基、置換されていてもよいアルケニル基または置換されていてもよいアリール基を表す。
Ｒ₉は、置換されていてもよいアルキル基、置換されていてもよいアルケニル基または置換されていてもよいアリール基を表す。
Ｒ₁₂は有機色素残基、置換基を有していてもよい複素環残基、置換基を有していてもよい芳香族環残基をあらわす。

X ₄ is a direct _{bond, -SO 2 -, - CO -} , - CH 2 NHCOCH 2 -, - CH 2 NHCONHCH 2 -, - CH 2 - or, -X ₅ -Y-X ₆ - represents a. X ₅ is -NH- or represents -O-, X ₆ represents a direct _{bond, -SO 2 -, - CO -} , - CH 2 NHCOCH 2 -, - CH 2 NHCONHCH 2 - or -CH ₂ - Represents. Y represents an alkylene group which may have a substituent, an alkenylene group which may have a substituent, or an arylene group which may have a substituent, having 1 to 20 carbon atoms.
v represents an integer of 1 to 10.
R ₃ and R ₄ are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted phenyl group, or R ₃ and R ₄ together. Represents an optionally substituted heterocyclic residue containing additional nitrogen, oxygen or sulfur atoms. In particular, a hydrogen atom is preferable because it is considered that the effect of suppressing metal deposition in the battery is high.
R ₅ , R ₆ , R ₇ and R ₈ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group or an optionally substituted aryl group.
R ₉ represents an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted aryl group.
R ₁₂ represents an organic dye residue, a heterocyclic residue which may have a substituent, and an aromatic ring residue which may have a substituent.

Examples of the organic dye residue represented by R ₁₂ include diketopyrrolopyrrole dyes, azo dyes such as azo, disazo, polyazo, phthalocyanine dyes, diaminodianthraquinone, anthrapyrimidine, flavantrons, anthanthrones, indans. Anthraquinone dyes such as throne, pyranthrone, violanthrone, quinacridone dyes, dioxazine dyes, perinone dyes, perylene dyes, thioindigo dyes, isoindoline dyes, isoindolinone dyes, quinophthalone dyes, selenium dyes Examples thereof include dyes and metal complex dyes. In particular, in order to enhance the effect of suppressing the short circuit of the battery due to metal, it is preferable to use an organic dye residue that is not a metal complex dye.

Examples of the heterocyclic residue and aromatic ring residue represented by R ₁₂ include thiophene, furan, pyridine, pyrazole, pyrrole, imidazole, isoindoline, isoindolinone, benzimidazolone, benzthiazole, benzine. Examples include triazole, indole, quinoline, carbazole, acridine, benzene, naphthalene, anthracene, fluorene, phenanthrene, anthraquinone, acridone and the like. These heterocyclic residues and aromatic ring residues are alkyl groups (methyl group, ethyl group, butyl group, etc.), amino groups, alkylamino groups (dimethylamino group, diethylamino group, dibutylamino group, etc.), nitro groups. Hydroxyl group, alkoxy group (methoxy group, ethoxy group, butoxy group, etc.), halogen (chlorine, bromine, fluorine, etc.), phenyl group (alkyl group, amino group, alkylamino group, nitro group, hydroxyl group, alkoxy group, halogen, etc.) And a substituent such as a phenylamino group (which may be substituted with an alkyl group, amino group, alkylamino group, nitro group, hydroxyl group, alkoxy group, halogen, etc.) May be.

<Binder>
The binder in the present invention is used to bind particles such as conductive carbon materials and other active materials, and these particles and a current collector.

The binder is not particularly limited as long as it has the above-mentioned function. For example, acrylic resin, polyurethane resin, polyester resin, phenol resin, epoxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, formaldehyde Resin, silicone resin, fluororesin, cellulose resin such as carboxymethylcellulose, synthetic rubber such as styrene-butadiene rubber and fluororubber, conductive resin such as polyaniline and polyacetylene, etc., polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene, etc. The high molecular compound containing these fluorine atoms is mentioned. Further, a modified product, a mixture, or a copolymer of these resins may be used. These binders can be used alone or in combination.
A polymer compound containing a fluorine atom such as polyvinylidene fluoride, polyvinyl fluoride, and tetrafluoroethylene is preferable.

<Solvent>
The solvent in the present invention is not particularly limited, but amides such as dimethylformamide, dimethylacetamide, methylformamide, amines such as N-methyl-2-pyrrolidone (NMP), dimethylamine, methyl ethyl ketone, acetone, cyclohexanone, etc. Examples include ketones, alcohols, glycols, cellosolves, amino alcohols, sulfoxides, carboxylic acid esters, phosphoric acid esters, ethers, nitriles, and water.

  Furthermore, a film forming aid, an antifoaming agent, a leveling agent, a preservative, a pH adjusting agent, a viscosity adjusting agent, and the like can be blended in the composition for forming a lithium secondary battery electrode as necessary.

  In the present invention, the first step of dispersing the active material in the solvent, the second step of adding, mixing, and dispersing the conductive carbon material, and the binder are made conductive in the second step. A mixture slurry is produced from the third step of adding at the same time as the carbon material, or subsequent to the second step, adding, mixing and dissolving, and kneading or dispersing.

  In the present invention, it is preferable to prepare a mixture slurry by adding a conductive carbon material or a binder immediately after producing the active material dispersion. The term “immediately after” indicates a time during which the dispersed state of the active material is maintained. Specifically, it can be confirmed by a particle size distribution described later. According to this step, it is possible to effectively coordinate the conductive carbon material to the active material particles dispersed to near the primary particle diameter, which seems to be effective in reducing the internal resistance of the electrode.

  The particle size distribution of the active material is a value obtained by sampling the slurry, diluting it to a predetermined concentration, and obtaining it with a grind gauge (JIS K5101), and this value is defined as the dispersed particle size of the active material.

  The dispersed particle size of the active material varies depending on the primary particle size of the active material to be used. Although it does not specifically limit, 50 micrometers or less, Preferably it is 30 micrometers or less, More preferably, 10 micrometers or less are preferable. When the dispersed particle diameter of the active material exceeds 50 μm, problems such as variations in the material distribution of the composite coating film and variations in the resistance distribution of the electrodes may occur.

  In the first step of the present invention, as a device used for obtaining a dispersion of the active material, a disperser usually used for pigment dispersion or the like can be used. For example, homogenizers (such as “Clairemix” manufactured by M Technique, “Filmix” manufactured by Primics), paint conditioners (manufactured by Red Devil), ball mills, sand mills (such as “Dynomill” manufactured by Shinmaru Enterprises), Lighter, pearl mill (such as “DCP mill” manufactured by Eirich), media type disperser such as coball mill, wet jet mill (“Genus PY” manufactured by Genus, “Starburst” manufactured by Sugino Machine, “Nanomizer” manufactured by Nanomizer, etc. , “Nanovaida” manufactured by Yoshida Kogyo Co., Ltd.), “Claire SS-5” manufactured by M Technique, “MICROS” manufactured by Nara Machinery Co., Ltd., and other roll mills, etc. is not. Moreover, these dispersers may be used independently and may be used in combination of 2 or more type. Furthermore, it is preferable to use a dispersion machine that has been subjected to a metal mixing prevention treatment from the dispersion machine.

  As the apparatus used in the first step, a media type disperser is particularly preferable. In order to uniformly disperse fine active material particles having strong agglomeration, it is difficult to overcome the high surface energy of the particles only with a shearing force. Therefore, it is important to use mechanical energy such as media collision force, friction force, and shear force. However, if excessive force is applied to crush the primary particles, active sites are generated on the crushing surface, resulting in an abnormal increase in viscosity of the dispersion system, or "dispersed particles" causing reaggregation. This increases the possibility of causing problems in the stability and coating suitability of the composite slurry. The active material dispersion in the present invention means a state in which the primary particles are not crushed and the secondary particles are dispersed to near the primary particle diameter.

  When using a media-type disperser, use a disperser in which the agitator and vessel are made of ceramic or resin, or use a disperser in which the surface of the metal agitator and vessel is treated with tungsten carbide spraying or resin coating. It is preferable. And as a medium, it is preferable to use ceramic beads, such as glass beads, zirconia beads, and alumina beads. Moreover, also when using a roll mill, it is preferable to use a ceramic roll. Only one type of dispersion device may be used, or a plurality of types of devices may be used in combination.

  In the first step of the present invention, it is preferable to use a dispersant. Dispersing the dispersant completely or partially in a solvent, and adding, mixing and dispersing the active material in the solution, while adsorbing and coating these dispersants to the active material while dispersing the active material close to the primary particles This is because it can be dispersed in a solvent. At this time, the active material concentration in the dispersion is preferably 30% by weight or more and 90% by weight or less, and more preferably 40% by weight or more and 80% by weight or less.

  The addition amount of the dispersant is determined by the primary particle diameter of the active material to be used, but the dispersant is 0 parts by weight or more and 5 parts by weight or less, preferably 0.03 parts by weight or more with respect to 100 parts by weight of the active material. 3 parts by weight or less, more preferably 0.05 parts by weight or more and 1 part by weight or less. Within the above range, the balance between dispersibility and ionic resistance is good, which is preferable.

  In the second step, a conductive carbon material is further added to the dispersion obtained by dispersing the active material prepared in the first step in a solvent, mixed, and kneaded or dispersed. The addition method is preferably performed while stirring, and a dispersing device may be used thereafter. The conductive carbon material can be used in a powder form, but it is preferable to use a dispersion in which the conductive carbon material is dispersed in a solvent in advance. At this time, a dispersant is used to obtain a dispersion in which the conductive carbon material is previously dispersed in the solvent. May be added.

  In addition, it is preferable to include a step of removing contaminants such as metallic foreign matters at least once in the first step or after, or in the second step or after. The active material and the conductive carbon material often contain metallic foreign matters (such as contamination and line contamination contained in the raw material) derived from their production process, and removing these metallic foreign matters This is important to prevent short-circuiting of the battery. In the present invention, the metallic foreign matter can be efficiently removed by adding a step of removing contamination when the aggregation of the active material and the conductive carbon material is loosened. Examples of methods for removing metallic foreign substances include iron removal with a magnet, filtration, and centrifugation.

  In the third step, a binder is further added to the dispersion composed of the active material and the conductive carbon material prepared in the second step, mixed and dissolved, and then kneaded or dispersed. The addition method is preferably performed while stirring, and a dispersing device may be used thereafter. The binder can be used in powder form, but it is preferable to use a binder solution or dispersion previously dissolved or dispersed in a solvent.

  In another preferred embodiment as the second step, a conductive material and a binder are simultaneously added to a dispersion obtained by dispersing the active material prepared in the first step in a solvent, and mixed and dissolved. Kneading or dispersing is performed. The addition method is preferably performed while stirring, and a dispersing device may be used thereafter. The conductive carbon material and the binder can be used in powder form, but a solution dissolved or dispersed in a solvent may be added, mixed, kneaded or dispersed. As a method for preparing a solution in which the conductive carbon material and the binder are dissolved or dispersed in a solvent, for example, the conductive carbon material and the binder are mixed in advance in a powder form, and preferably, while stirring. A method of mixing and dissolving in a solvent and kneading or dispersing can be mentioned, but the order of addition of each component is not particularly limited.

In another preferred embodiment as the second step, a mixed powder in which a conductive carbon material and a binder are mixed in advance is added, mixed, and kneaded or dispersed. Examples of the method for preparing the mixed powder in which the conductive carbon material and the binder are mixed include a method in which the conductive carbon material powder and the binder powder are sufficiently mixed with a tumbler or the like. The order and mixing method are not particularly limited. For example, a mixing method with a strong share that involves a mechanochemical reaction may be used.
When the conductive material and the binder are added at the same time as the second step, it is not necessary to perform the third step, but if necessary, use both the second step and the third step. It is also possible to add a binder.

  As the dispersed particle diameter of the conductive carbon material and the binder in the mixture slurry, the slurry is sampled and diluted to a predetermined concentration so that the particle size distribution (JIS K5101) by a grind gauge is 20 μm or less.

  As an apparatus used in the second and third steps of the present invention, a disperser usually used for pigment dispersion or the like can be used. For example, mixers such as dispersers, homomixers, planetary mixers, homogenizers (“Clairemix” manufactured by M Technique, “Filmix” manufactured by Primics), paint conditioners (manufactured by Red Devil), ball mills, sand mills ( Media type dispersers such as “Dynomill” manufactured by Shinmaru Enterprises, Inc.), Attritor, Pearl Mill (“DCP Mill” manufactured by Eirich), Coball Mill, etc., Wet Jet Mill (“Genus PY” manufactured by Genus, Sugino Machine Co., Ltd.) "Starburst" manufactured by Nanomizer, "Nanomizer" manufactured by Nanomizer, "Nanovaida" manufactured by Yoshida Kogyo Co., Ltd.), "Claire SS-5" manufactured by M-Technique, and "MICROS" manufactured by Nara Machinery Co., etc. Roll mills, etc. Not intended to be constant. Moreover, these dispersers may be used independently and may be used in combination of 2 or more type. Furthermore, it is preferable to use a dispersion machine that has been subjected to a metal mixing prevention treatment from the dispersion machine.

  The composite material layer of the present invention is obtained by applying the composition for forming a lithium secondary battery electrode of the present invention to a substrate and further drying.

<Base material>
The material and shape of the substrate used for the electrode are not particularly limited, and those suitable for various secondary batteries can be appropriately selected.
For example, examples of the material for the base material include metals and alloys such as aluminum, copper, nickel, titanium, and stainless steel. In the case of a lithium ion battery, aluminum is particularly preferable as the positive electrode material, and copper is preferable as the negative electrode material.
In general, a flat foil is used as the shape, but a roughened surface, a perforated foil, or a mesh current collector can also be used. Moreover, you may use the base material which apply | coated the electroconductive composition.

Although it depends on the coating method, the viscosity of the mixture slurry is preferably 100 mPa · s or more and 30,000 mPa · s or less in the range of 30 to 90% by weight of the solid content.
In the viscosity range where coating is possible, the active material particles are preferably contained as much as possible. For example, the ratio of the active material to the total solid content in the electrode mixture slurry is 70% by weight or more and 98.5% by weight or less. Is preferable, and 80% by weight or more and 95% by weight or less is more preferable.

  Moreover, it is preferable that the ratio of the dispersing agent to the mixture slurry solid content is 15% by weight or less.

  When the conductive assistant is included, the ratio of the conductive assistant to the solid mixture solid content is preferably 0.1 to 15% by weight.

  When the binder is included, the ratio of the binder to the solid mixture slurry solid content is preferably 0.1 to 15% by weight.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. The active materials, dispersants, conductive carbon materials, binders, thickeners, mixers, and dispersers used in Examples and Comparative Examples are shown below.

・分散剤B（特許４４２０１２３ 表３ 分散剤Jに記載の塩基性官能基を有するトリアジン誘導体）

・K-15（DSP五協フード＆ケミカル社製、ポリビニルピロリドン）
・ジョンクリル６２−J（ジョンソンポリマー社製、スチレンアクリル共重合樹脂）
・＃１１２０（ダイセルファインケム社製、カルボキシメチルセルロース（ＣＭＣ）） <Active material>
-Lithium iron phosphate (LiFePO ₄ , average primary particle size 100 nm, specific surface area 20 m ² / g)
Lithium cobaltate (LiCoO ₂ , average primary particle size 800 nm, specific surface area 1.3 m ² / g)
Lithium manganate (LiMn ₂ O ₄ , average primary particle size 800 nm, specific surface area 1.4 m ² / g)
・ Lithium titanate (Li ₄ Ti ₅ O ₁₂ , primary particle diameter 700 nm, specific surface area 7 m ² / g)
<Dispersant>
Dispersant A (Patent 4240157, Table 1 Triazine derivative having acidic functional group described in Dispersant A)

Dispersant B (Patent 4420123, triazine derivative having basic functional group described in Table 3 Dispersant J)

・ K-15 (DSP Gokyo Food & Chemical Co., Polyvinylpyrrolidone)
・ Johncrill 62-J (manufactured by Johnson Polymer Co., Ltd., styrene acrylic copolymer resin)
# 1120 (Daicel Finechem, carboxymethyl cellulose (CMC))

<Conductive carbon material>
DENKA BLACK HS-100 (manufactured by Denki Kagaku Kogyo Co., Ltd., acetylene black, hereinafter abbreviated as “HS-100”)
・ EC-300J (manufactured by Akzo, Ketjen Black)
・ VGCF-H (Showa Denko, carbon nanotube)

<Binder>
KF polymer W # 7200 (manufactured by Kureha, vinylidene fluoride homopolymer, hereinafter abbreviated as “W # 7200”)
KF polymer L # 7208 (manufactured by Kureha, N-methyl-2-pyrrolidone solution containing 8.0% by weight of vinylidene fluoride homopolymer, hereinafter abbreviated as "L # 7208")
Fine powder 30-J (Mitsui / Dupont Fluorochemicals, polytetrafluoroethylene, hereinafter abbreviated as “30-J”)

<Mixer>
・ FM mixer (Nippon Coke Kogyo Co., Ltd.)

<Dispersing machine>
・ Disper (Primix Co., Ltd., TK homodisper)
・ Homogenizer (Filmix, manufactured by Primix)
・ Sand mill (Shinmaru Enterprises, Dynomill)
Planetary mixer (Primix Co., Ltd., TK Hibismix)
・ Jet mill (manufactured by Yoshida Machine Industry Co., Ltd., Nanovaida)
-Planetary mixer with disperser (Primics, Hibis Disper mix)

<Production of composite slurry>
(Example 1) Production of positive electrode mixture slurry 97.5 parts by weight of N-methyl-2-pyrrolidone and 90 parts by weight of lithium iron phosphate were added to a container, and zirconia beads were used at a diameter of 1.25 mm using a sand mill. Dispersion was performed for minutes, and zirconia beads were separated to obtain an active material dispersion. Subsequently, 5 parts by weight of HS-100 was added to the active material dispersion, and after dispersing for 10 minutes using a homogenizer, 62.5 parts by weight of L # 7208 was added and dispersed for 5 minutes to obtain a positive electrode mixture slurry. Obtained.

(Example 2) Production of positive electrode mixture slurry An active material dispersion was obtained in the same manner as in Example 1. In a container, 20 parts by weight of N-methyl-2-pyrrolidone and 5 parts by weight of HS-100 were collected and dispersed with a homogenizer for 10 minutes to prepare a conductive carbon material dispersion. Then, the conductive carbon material dispersion is added to the active material dispersion under stirring with a disper and stirred for 5 minutes, and then 62.5 parts by weight of L # 7208 is further added and stirred for 10 minutes to form a positive electrode mixture slurry. Obtained.

(Example 3) Production of positive electrode mixture slurry An active material dispersion was obtained in the same manner as in Example 1. 5 parts by weight of HS-100 and 5 parts by weight of W # 7200 were sampled and mixed using an FM mixer to obtain a mixed powder. After 90 parts by weight of N-methyl-2-pyrrolidone is collected in a container, the above mixed powder is added, dissolved, and mixed with stirring with a disper, and further dispersed for 5 minutes with a homogenizer to mix the conductive carbon material and the binder. A dispersion solution was obtained. Then, a dispersion solution of the conductive carbon material and the binder was added to the active material dispersion under stirring with a disper and dispersed for 10 minutes to obtain a positive electrode mixture slurry.

(Example 4) Production of positive electrode mixture slurry An active material dispersion was obtained in the same manner as in Example 1. Subsequently, 5 parts by weight of HS-100 and 5 parts by weight of W # 7200 were sampled and mixed using an FM mixer to obtain a mixed powder. Then, 55 parts by weight of N-methyl-2-pyrrolidone was added to the active material dispersion while stirring with a disper, and the mixed powder was further added and dissolved and mixed for 10 minutes. Further, the mixture was dispersed for 5 minutes using a homogenizer to obtain a positive electrode mixture slurry.

(Example 5) Production of positive electrode mixture slurry 97.5 parts by weight of water and 90 parts by weight of lithium iron phosphate were collected in a container and dispersed with zirconia beads φ1.25 mm using a sand mill for 30 minutes, and then zirconia. The beads were separated to obtain an active material dispersion. Subsequently, 5 parts by weight of HS-100 was added to the active material dispersion and dispersed for 5 minutes using a homogenizer to obtain a dispersion of the active material and the conductive carbon material. On the other hand, # 1120 was dissolved in water using a disper to prepare a 3% by weight aqueous solution of CMC. Then, 33.3 parts by weight of CMC 3% by weight aqueous solution and 6.7 parts by weight of 30-J are added to the dispersion of the active material and the conductive carbon material while stirring with a disper, and dispersed for 10 minutes to obtain a positive electrode mixture slurry. Got.

(Example 6) Production of positive electrode mixture slurry An active material dispersion was obtained in the same manner as in Example 5. # 1120 was dissolved in water using a disper to prepare a 3% by weight CMC aqueous solution. Then, 5 parts by weight of HS-100, 33.3 parts by weight of CMC 3% by weight aqueous solution, and 6.7 parts by weight of 30-J are collected and dispersed for 5 minutes using a homogenizer, and the conductive carbon material and binder are collected. A dispersion was obtained. Subsequently, the dispersion of the conductive carbon material and the binder was added to the active material dispersion with stirring with a disper and dispersed for 10 minutes to obtain a positive electrode mixture slurry.

(Example 7) Production of positive electrode mixture slurry A positive electrode mixture slurry was obtained by the same production method as in Example 1, except that the time of the sand mill used in Example 1 was changed from 30 minutes to 10 minutes.

(Example 8) Production of positive electrode mixture slurry 97.5 parts by weight of N-methyl-2-pyrrolidone and 90 parts by weight of lithium iron phosphate were added to a container, and dispersed for 30 minutes using a jet mill. A substance dispersion was obtained. Subsequently, 5 parts by weight of HS-100 was added to the active material dispersion, and after dispersing for 10 minutes using a homogenizer, 62.5 parts by weight of L # 7208 was added and dispersed for 5 minutes to obtain a positive electrode mixture slurry. Obtained.

(Example 9) Production of positive electrode mixture slurry 73.4 parts by weight of N-methyl-2-pyrrolidone was sampled in a container, and 0.1 part by weight of dispersant A was added and dissolved. 90 parts by weight of lithium iron phosphate was added to the solution, and dispersed with zirconia beads φ1.25 mm for 30 minutes using a sand mill, and the zirconia beads were separated to obtain an active material dispersion. Subsequently, 5 parts by weight of HS-100 was added to the active material dispersion, and after dispersing for 10 minutes using a homogenizer, 61.3 parts by weight of L # 7208 was added and dispersed for 5 minutes to obtain a positive electrode mixture slurry. Obtained.

(Example 10) Production of positive electrode mixture slurry A positive electrode mixture slurry was obtained by the same production method as in Example 9, except that lithium cobalt oxide was used instead of lithium iron phosphate used in Example 9. It was.

(Example 11) Production of positive electrode mixture slurry A positive electrode mixture slurry was obtained by the same production method as in Example 9, except that lithium manganate was used instead of lithium cobaltate used in Example 9. .

(Example 12) Production of negative electrode mixture slurry A negative electrode mixture slurry was obtained by the same production method as in Example 9 except that lithium titanate was used instead of lithium cobaltate used in Example 9. .

(Example 13) Production of positive electrode mixture slurry An active material dispersion was obtained in the same manner as in Example 9. 5 parts by weight of EC-300J and 4.8 parts by weight of W # 7200 were sampled and mixed using an FM mixer to obtain a mixed powder. In a container, 50 parts by weight of N-methyl-2-pyrrolidone was sampled, 0.2 part by weight of dispersant A was added and dissolved, and then the above mixed powder was added to the active material dispersion under stirring with a disper, Furthermore, it stirred for 10 minutes with the homogenizer, and obtained the dispersion solution of the conductive carbon material and the binder. Then, a dispersion solution of the conductive carbon material and the binder was added to the active material dispersion under stirring with a disper and dispersed for 10 minutes to obtain a positive electrode mixture slurry.

(Example 14) Production of positive electrode mixture slurry A positive electrode mixture slurry was obtained by the same production method as in Example 13 except that VGCF-H was used instead of EC-300J used in Example 13. .

(Example 15) Production of positive electrode mixture slurry A positive electrode mixture slurry was obtained by the same production method as in Example 9 except that Dispersant B was used instead of Dispersant A used in Example 9. .

(Example 16) Production of positive electrode mixture slurry A positive electrode mixture slurry was obtained by the same production method as in Example 9, except that K-15 was used instead of Dispersant A used in Example 9. .

Example 17 Production of Positive Electrode Mixture Slurry # 1120 was dissolved in water using a disper to prepare a 3% by weight CMC aqueous solution. Then, 69 parts by weight of water, 15 parts by weight of CMC 3% by weight aqueous solution, and 90 parts by weight of lithium iron phosphate are collected in a container and dispersed with zirconia beads φ1.25 mm using a sand mill for 30 minutes, and then the zirconia beads are separated. Thus, an active material dispersion was obtained. Subsequently, 50 parts by weight of water, 18.3 parts by weight of CMC 3% by weight aqueous solution and 5 parts by weight of HS-100 were added, 6.7 parts by weight of 30-J was sampled, dispersed using a homogenizer, and conductive. A dispersion of a conductive carbon material and a binder was obtained. Then, the dispersion of the conductive carbon material and the binder was added to the active material dispersion while stirring the dispersion, and the mixture was stirred for 10 minutes to obtain a positive electrode mixture slurry.

(Example 18) Production of positive electrode mixture slurry In a container, 82.1 parts by weight of water, 2.9 parts by weight of Joncryl 62-J, and 90 parts by weight of lithium iron phosphate were collected, and zirconia beads φ1.25 mm The mixture was dispersed for 30 minutes using a sand mill, and then the zirconia beads were separated to obtain an active material dispersion. Subsequently, 5 parts by weight of HS-100 was added to the active material dispersion and dispersed for 10 minutes using a homogenizer to obtain an active material and conductive carbon material dispersion. On the other hand, # 1120 was dissolved in water using a disper to prepare a 3% by weight aqueous solution of CMC. Then, 33.3 parts by weight of CMC 3% by weight aqueous solution and 5 parts by weight of 30-J were sampled and added to the active material and the conductive carbon dispersion under stirring with a dispersion and dispersed for 10 minutes to obtain a positive electrode mixture slurry. It was.

(Comparative Example 1) Production of positive electrode mixture slurry 90 parts by weight of lithium iron phosphate, 5 parts by weight of HS-100, 5 parts by weight of W # 7200, 122 parts by weight of N-methyl-2-pyrrolidone were collected. The mixture was dispersed for 90 minutes by a planetary to obtain a positive electrode mixture slurry.

Comparative Example 2 Production of Positive Electrode Mixture Slurry # 1120 was dissolved in water using a disper to prepare a 3% by weight CMC aqueous solution. In a container, 97.5 parts by weight of water, 90 parts by weight of lithium iron phosphate, 33.3 parts by weight of HS-100, CMC 3% by weight aqueous solution, and 6.7 parts by weight of 30-J were sampled, and planetary. Was dispersed for 90 minutes to obtain a positive electrode mixture slurry.

(Comparative Example 3) Production of Positive Electrode Mixture Slurry A positive electrode mixture slurry was obtained by the same production method as Comparative Example 1 except that lithium cobalt oxide was used instead of lithium iron phosphate used in Comparative Example 1. It was.

Comparative Example 4 Production of Positive Electrode Mixture Slurry A positive electrode mixture slurry was obtained by the same production method as Comparative Example 1 except that lithium manganate was used instead of lithium iron phosphate used in Comparative Example 1. It was.

(Comparative Example 5) Production of Negative Electrode Mixture Slurry A positive electrode mixture slurry was obtained by the same production method as in Comparative Example 1, except that lithium titanate was used instead of lithium iron phosphate used in Comparative Example 1. It was.

Comparative Example 6 Production of Positive Electrode Mixture Slurry 5 parts by weight of HS-100, 5 parts by weight of W # 7200, and 122 parts by weight of N-methyl-2-pyrrolidone were sampled and dispersed for 30 minutes using a homogenizer. Subsequently, 90 parts by weight of lithium iron phosphate was added to the obtained dispersion and dispersed with a disper for 30 minutes to obtain a positive electrode mixture slurry.

Comparative Example 7 Production of Positive Electrode Mixture Slurry 5 parts by weight of HS-100, 5 parts by weight of W # 7200, and 122 parts by weight of N-methyl-2-pyrrolidone were sampled and dispersed for 30 minutes using a homogenizer. Subsequently, 90 parts by weight of lithium iron phosphate was added to the obtained dispersion and dispersed for 30 minutes with a homogenizer to obtain a positive electrode mixture slurry.

Comparative Example 8 Production of Positive Electrode Mixture Slurry An active material dispersion was obtained in the same manner as in Example 9. Subsequently, 60 parts by weight of L # 7208 was added to the active material dispersion under stirring with a disper and dispersed for 10 minutes. Furthermore, after adding 5 parts by weight of HS-100, the mixture was dispersed for 5 minutes using a homogenizer to obtain a positive electrode mixture slurry.

(Comparative Example 9) Production of positive electrode mixture slurry 90 parts by weight of lithium iron phosphate and 56.3 parts by weight of W # 7208 are added to a container and dispersed for 30 minutes using a planetary mixer with a disperser. A dispersion was obtained. 5 parts by weight of HS-100, 6.3 parts by weight of L # 7208, and 65 parts by weight of N-methyl-2-pyrrolidone are collected and dispersed with a homogenizer to obtain a dispersion solution of a conductive carbon material and a binder. It was. Subsequently, a dispersion solution of a conductive carbon material and a binder was added to the active material dispersion under stirring with a disper and dispersed for 10 minutes to obtain a positive electrode mixture slurry.

(Comparative Example 10) Production of positive electrode mixture slurry 38.6 parts by weight of N-methyl-2-pyrrolidone and 90 parts by weight of lithium iron phosphate were collected in a container and dispersed with a disper for 10 minutes. Got. Subsequently, 37.4 parts by weight of N-methyl-2-pyrrolidone and 5 parts by weight of HS-100 were collected in a container and mixed with a disper for 10 minutes to obtain a conductive carbon material mixture. Further, under active stirring of the disper, the active material mixture is added to the conductive carbon material mixture, and then 62.5 parts by weight of L # 7208 is added and mixed for 10 minutes, and then dispersed with a homogenizer for 10 minutes. The mixture was dispersed for 30 minutes with a planetary to obtain a positive electrode mixture slurry.

  It shows in Table 1 about the manufacturing method of the compound-material slurry obtained by the Example and the comparative example.

ＮＭＰ：N−メチル−２−ピロリドン、ＡＢ：アセチレンブラック、ＫＢ：ケッチェンブラック、ＣＮＴ：カーボンナノチューブ、ＰＶＤＦ：フッ化ビニリデン単独重合体

NMP: N-methyl-2-pyrrolidone, AB: Acetylene black, KB: Ketjen black, CNT: Carbon nanotube, PVDF: Vinylidene fluoride homopolymer

  Hereinafter, test methods and test results for each of the mixed slurry, electrode, and battery manufactured above will be described.

<Evaluation of particle size of active material dispersion and mixture slurry>
The particle size of the active material dispersion and the mixture slurry was determined by judgment using a grind gauge (JIS K5101). Table 1 shows the particle sizes of the dispersions prepared in Examples and Comparative Examples.

  As shown in Table 1, the particle sizes of the composite slurry produced in Examples 1 to 18 and Comparative Example 8 were all small, indicating that they were in a good dispersion state. By dispersing the active material and the solvent first, strong secondary aggregation of the active material is crushed, and the effect is considered to be maintained even after the mixture slurry. Furthermore, in Examples 1-6, 9-18, and Comparative Example 8 using a media-type disperser, it can be seen that the effect is particularly high and the dispersion is uniformly performed. On the other hand, the mixed material slurry produced in Comparative Examples 1-6, 9, and 10 has a large particle size, and the secondary aggregated particles are not unraveled. In Comparative Example 9, the active material is pre-dispersed. However, since it is a shear force type dispersion, it is considered that the active material having strong secondary aggregation is difficult to be agglomerated.

<Stability of composition>
Each lithium secondary battery electrode forming composition prepared in the above Examples and Comparative Examples was stored at 25 ° C. and observed for phenomena such as solid aggregation, sedimentation, and separation from the solvent. Judgment was made visually and evaluated according to the following criteria. Usually, if the evaluation is C or higher, it is at a level where there is no practical problem.

((Evaluation criteria)
A: Phenomenon such as solid aggregation, sedimentation and separation from the solvent was not observed for 3 weeks or more.
B: Phenomena such as agglomeration of solids, sedimentation, and separation from the solvent were observed within 2 to 3 weeks.
C: Phenomena such as solid agglomeration, sedimentation, and separation from the solvent were observed between one week and two weeks.
D: Phenomena such as solid agglomeration, sedimentation, and separation from the solvent were observed within one week.

  Table 2 shows the stability of the compositions obtained in Examples and Comparative Examples.

  As shown in Table 2, the composite slurry produced in the examples showed better temporal stability than the comparative examples. In addition to the uniform dispersion of the mixture slurry, the dispersion stability is considered to be further improved by the active material tip dispersion. Furthermore, in Examples 9-12 and 15-18, the dispersing agent is used, and it is expected that the state where the active material and the conductive carbon material are uniformly dispersed can be maintained for a long time.

<Manufacture of positive electrode>
Each positive electrode mixture slurry obtained in Examples 1 to 11, 13 to 18 and Comparative Examples 1 to 4 and 6 to 10 was applied onto a 20 μm thick aluminum foil serving as a current collector using a die coater. And dried in a drying furnace at 120 ° C. to obtain a coated product. The coating amount was 8.0 mg / cm ² . Then, it rolled with the roll press machine and cut | judged to 30 mm x 50 mm, and produced the positive electrode, respectively.

<Manufacture of negative electrode mixture slurry>
90 parts by weight of mesophase carbon MFC (MCMB6-28, manufactured by Osaka Gas Chemical Co., Ltd.) and 10 parts by weight of W # 7200 were collected as a negative electrode active material and added to 100 parts by weight of N-methyl-2-pyrrolidone, and then a homogenizer. The mixture was stirred for 30 minutes to obtain a negative electrode mixture slurry.

<Manufacture of negative electrode>
The negative electrode mixture slurry using Example 12, Comparative Example 5 and the above mesophase was applied onto a 20 μm thick copper foil serving as a current collector using a die coater, and dried in a 120 ° C. drying oven. I got a work. The coating amount was 5.0 mg / cm ² . Then, it rolled with the roll press machine and cut | judged to 35 mm x 55 mm, and produced the negative electrode.

<Adhesion test>
In the electrodes having a composite material layer thickness of 90 μm prepared in the above examples and comparative examples, the incisions from the electrode surface to the depth reaching the current collector are made by using a knife with 6 mm grids in each of the vertical and horizontal directions at intervals of 2 mm. A cut was made. An adhesive tape was applied to the cut and immediately peeled off, and the degree of the active material falling off was determined by visual judgment. The evaluation criteria are as follows. Usually, if the evaluation is C or higher, it is at a level where there is no practical problem.

(Evaluation criteria)
A: No peeling B: Partial peeling C: Partial peeling D: Half or more peeling

<Electrode flexibility>
Each electrode sample produced in the above Examples and Comparative Examples was formed into a strip shape and wound so that the current collector side was in contact with a metal rod having a diameter of 3 mm. The state of cracks on the electrode surface that occurred during winding was determined by visual observation. It means that the one that does not crack is more flexible. The evaluation criteria are as follows. Usually, if the evaluation is C or higher, it is at a level where there is no practical problem.

(Evaluation criteria)
A: No cracks.
B: Some cracks are observed.
C: Some cracks are seen.
D: Cracks are observed as a whole.

  Table 3 shows the adhesion and flexibility tests of the electrodes prepared in Examples and Comparative Examples.

  As shown in Table 3, the electrode produced in the example showed better adhesion and flexibility than the electrode produced in the comparative example. Since the binder is added after the active material is sufficiently dispersed, the binding components are not biased in the pores of the agglomerated active material, which is considered to be due to a uniform coating distribution.

<Manufacture of batteries>
Nickel lead wires were attached to the positive electrode and the negative electrode, respectively. Subsequently, in the combinations shown in Table 4, each positive electrode and negative electrode were laminated via a polypropylene porous separator (thickness 20 μm, porosity 50%) to form a bag-like aluminum laminate container (60 mm × 80 mm). The water vapor permeability was 0.9 g / m ² / day). In a dry Ar atmosphere, a nonaqueous electrolyte solution, which is an ethylene carbonate solution containing LiPF ₆ at a rate of 1 mol / L, was injected into the container, and then the container was sealed to manufacture batteries.

<Battery evaluation>
The batteries of Examples 1 to 11, 13 to 18 and Comparative Examples 1 to 4 and 6 to 10 were subjected to constant current and constant voltage charging at 25 ° C. with an upper limit voltage of 4.3 V and a charging current of 0.2 C. Then, the discharge capacity when performing constant current discharge at 25 ° C. with a discharge current of 0.2 C and a lower limit voltage of 2.0 V was determined as a 0.2 C capacity. Subsequently, constant current and constant voltage charging was performed at 25 ° C. with an upper limit voltage of 4.3 V and a charging current of 0.2 C, and then a constant current discharge was performed at 25 ° C. with a discharge current of 5 C and a lower limit voltage of 2.0 V. The discharge capacity was determined as 5 C capacity. The ratio of the 5C capacity to the 0.2C capacity was defined as the discharge capacity maintenance rate. The evaluation results of the battery are shown in Table 4.

  The batteries of Example 12 and Comparative Example 5 were charged at a constant current and a constant voltage at an upper limit voltage of 2.7 V and a charge rate of 0.2 C at 25 ° C., and then discharged at a discharge rate of 0.2 C at 25 ° C. The discharge capacity when performing constant current discharge at the lower limit voltage of 1.8 V was determined as 0.2 C capacity. Subsequently, constant current and constant voltage charging was performed at 25 ° C. at an upper limit voltage of 2.7 V and a charging rate of 0.2 C. The discharge capacity was determined as 5 C capacity. The ratio of 5C capacity to 0.2C capacity was defined as the discharge capacity retention rate. The evaluation results of the battery are shown in Table 4.

  As shown in Table 4, the batteries produced in the examples exhibited better discharge maintenance ratios than the comparative examples. As shown in Table 1, in Comparative Examples 1 to 5, 9, and 10, the particle size of the positive electrode mixture slurry is large. The secondary aggregation of the active material is not solved and the area in contact with the electrolytic solution is reduced, so that the ionic resistance is considered as a factor. Moreover, in the comparative example 7, it is disperse | distributing for a long time with a homogenizer, and the mechanical stress concerning a compound material slurry is large. Therefore, although the active material is unraveled, it is considered that the structure of the conductive carbon material was also cut at the same time, and the electronic resistance was increased. Further, in Comparative Examples 8 and 9, the binder is added during the dispersion of the active material or immediately after the dispersion of the active material, and then the conductive carbon material is added. Therefore, it is surmised that the binding component adsorbed to the active material increases and the ionic resistance of the active material increases.

Claims (12)

A method for producing a slurry for a secondary battery electrode comprising a first step of dispersing an active material in a solvent, and a second step of adding, mixing, kneading or dispersing the conductive carbon material, A binder is added at the same time as the conductive carbon material in the second step, or, after the second step, includes a third step of adding, mixing, dissolving, kneading or dispersing. A method for producing a slurry for a secondary battery electrode. 2. The method for producing a slurry for a secondary battery electrode according to claim 1, wherein a conductive carbon material dispersion in which a conductive carbon material is previously dispersed in a solvent is used. The method for producing a slurry for a secondary battery electrode according to claim 1 or 2, wherein a binder solution or dispersion in which the binder is previously dissolved or dispersed in a solvent is used. The method for producing a slurry for a secondary battery electrode according to claim 1, wherein a mixed powder in which a conductive carbon material and a binder are mixed in advance is used. 5. The method for producing a slurry for a secondary battery electrode according to claim 1, wherein in the first step, the dispersed particle diameter of the active material is 10 μm or less. The method for producing a slurry for a secondary battery electrode according to any one of claims 1 to 5, wherein in the first step, the dispersion is further performed using a media-type disperser. The method for producing a slurry for a secondary battery electrode according to any one of claims 1 to 6, wherein the slurry is further dispersed together with a dispersant in the first step. The active material is a positive electrode active material, has a BET specific surface area of ^{2 to} 40 m ² / g, a primary particle size of 30 to 500 nm, and is coated with conductive carbon. The olivine type lithium phosphorus represented by the following general formula (1) It is acid metal particle, The manufacturing method of the mixture slurry for secondary battery electrodes in any one of Claims 1-7 characterized by the above-mentioned.
General formula (1): LiFe _1-x M _x PO ₄ (0 ≦ x ≦ 1)
(In the formula, M represents at least one metal element selected from the group consisting of Mn, Co, Ni and V.) 8. The spinel-type lithium titanate particles having a BET specific surface area of ^{2 to} 40 m ² / g and a primary particle diameter of 30 nm to 1 μm, wherein the active material is a negative electrode active material. The manufacturing method of the composite material slurry for secondary battery electrodes. The mixture slurry for secondary battery electrodes manufactured by the manufacturing method in any one of Claims 1-9. The electrode for secondary batteries formed by apply | coating the mixture slurry of Claim 10 to a base material. A secondary battery comprising the electrode according to claim 11.

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