JP6380642B1 - Dispersant, dispersion composition, battery dispersion composition, electrode, battery - Google Patents

Abstract

An object of the present invention is to provide a battery having excellent characteristics as well as reducing the ionic resistance and reaction resistance as well as reducing the electronic resistance with good dispersibility as compared with a conventional dispersant.
The object is to provide a dispersant containing a triazine derivative represented by the general formula (1) and an amine or an inorganic base, and a dispersion composition comprising the dispersant, a carbon material, and a solvent. Further, the invention is solved by the dispersion composition comprising a binder, and the dispersion composition for a battery further comprising an active material in addition to the dispersion composition.
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Description

  The present invention relates to a dispersant, a dispersion composition, a battery dispersion composition, an electrode, and a battery.

  Carbon materials are widely used as conductive aids in the battery field, and in order to reduce battery resistance and obtain high performance, a conductive path is efficiently formed in the electrode by high-precision control of the carbon material distribution. There is a need.

  For this purpose, it is necessary to disperse the carbon material uniformly and at a high concentration in the solution. However, the carbon material, which is a nanoparticle having a large surface area, has a strong cohesive force between the carbon materials and is stable not only in the initial stage but also after aging. It is difficult to produce a simple dispersion.

  In order to solve these problems, various dispersants have been actively studied. For example, in Patent Document 1 and Patent Document 2, a carbon material dispersion is prepared using a polymer dispersant such as polyvinyl pyrrolidone or polyvinyl butyral and used as a battery composition.

  However, since these polymer dispersants themselves have viscosity, particularly when used for carbon materials with high specific surface areas such as carbon nanotubes that are known for high conductivity, the amount of dispersant required increases and the viscosity of the dispersion liquid increases. As a result, the coating property was lowered and a good electrode could not be obtained.

  In addition, the electrolyte solution swells by absorbing in the battery, the contact state between the carbon materials or between the carbon material and the active material or the current collector is broken, the appropriately formed conductive path is cut, and the resistance of the battery There is also a problem that the cycle life is deteriorated.

  Furthermore, the dispersant dissolved in the electrolyte increases the viscosity of the electrolyte and decreases the diffusibility of the electrolyte ions, thereby deteriorating the battery resistance. Since the electrolytic solution is particularly affected by an increase in viscosity at low temperatures, the deterioration of ionic resistance at low temperatures becomes significant.

  On the other hand, Patent Document 3 discloses a battery dispersion composition using a dispersant in which an amine is added to an acidic derivative of triazine. These have no viscosity like a polymer, and appropriately cause charge repulsion in a solvent such as N-methyl-2-pyrrolidone, which is an aprotic polar solvent, to enable production of a good dispersion.

  However, since these dispersants are also insulating components themselves, it is useful to improve battery characteristics by forming an efficient conductive path, but it is the limit to maximize the conductivity inherent to carbon materials. It cannot meet the demand for further lower resistance. Moreover, reduction of resistance components such as ion resistance and reaction resistance other than electronic resistance cannot be realized.

  Patent Document 4 discloses a battery composition in which an amine is added to a triazine derivative having an aromatic hydroxyl group or an aromatic thiol group. These are said to be excellent in dispersion stability of the carbon material and to improve the wettability of the electrolytic solution. However, similarly, reduction of resistance components such as ion resistance and reaction resistance other than electronic resistance cannot be realized.

  In addition, as a method of obtaining a carbon material pretreated with a dispersant, completely or partially dissolved in a basic aqueous solution to which an amine or an inorganic base is added, and the carbon material is added and mixed and dispersed in the solution. A method is described in which these dispersants act (for example, adsorb) on a carbon material.

  However, since the dispersants of Patent Document 3 and Patent Document 4 are not only highly soluble in the dispersion but also easily eluted into the electrolyte, the eluted dispersant is diffused in the battery to counter electrode, separator, and exterior. There was also a concern of adversely affecting peripheral members such as materials.

  In Patent Document 5, a carbon material dispersion is manufactured using a triazine derivative and polyvinyl alcohol in combination as a dispersant, and an electrode and a secondary battery are manufactured. This is to provide a dispersion with high concentration, excellent storage stability, and good adhesion (peel strength) of the coated electrode (coating film), but the advantages of triazine derivatives and polyvinyl alcohol are simplified. Because it was only added to the above, it was not possible to expect an effect that exceeded each performance.

  In addition, the triazine derivative described in Patent Document 5 has a problem of solubility in an electrolytic solution, similarly to the triazine derivatives described in Patent Document 3 and Patent Document 4.

  By the way, the performance required for batteries is increasing more and more in recent years. For example, in mobile applications, smartphones are required to support more complex applications on a large screen, and even though power consumption is high, even faster charging, longer operation, thinner, smaller, and lighter weight Is also required at the same time. In addition, with the spread of wearable terminals such as watches, smaller and higher energy density batteries have become necessary. For in-vehicle applications, high output is required, but for hybrid vehicles where low capacity has been allowed, batteries with excellent balance in all characteristics have been required for plug-in hybrid vehicles and electric vehicles. .

Japanese Patent Laid-Open No. 2003-157846 JP 2011-184664 A International Publication No. 2008/108360 JP 2010-61932 A JP2015-101615A

  In view of the above background, the present invention not only reduces electronic resistance with good dispersibility, but also reduces ionic resistance and reaction resistance at room temperature and low temperature, as compared with conventional dispersants, and further excellent characteristics. It is a problem to provide a battery. In addition, it was also an object to eliminate concerns about problems with peripheral members caused by elution of the dispersant into the electrolytic solution and to improve electrode adhesion (peel strength).

  As a result of intensive studies to solve the above problems, the present inventors have obtained a dispersion composition using a dispersant containing a triazine derivative represented by the following general formula (1) and an amine or an inorganic base, The present inventors have found that not only the electronic resistance can be reduced by forming a good conductive path but also the ionic resistance and reaction resistance can be reduced, and the present invention has been made.

Furthermore, since the dispersant containing the triazine derivative represented by the general formula (1) and an amine or an inorganic base has low solubility, there is no fear of inconvenience due to elution into the electrolytic solution. The reason for this is considered to be that the crystallinity is increased and the solubility is suppressed by a structure having high hydrogen bonding properties in which two —NH—R ¹ and two hydroxyl groups are directly bonded to one triazine ring. In addition, since strong interaction such as hydrogen bonding is likely to occur, it is likely to act on the carbon material, and sufficient dispersibility can be exhibited even if the solubility in the dispersion is low.

  Further, when the triazine derivative represented by the general formula (1) and the polymer dispersant are used in combination, the synergy that specifically improves the adhesion (peel strength) between the carbon materials and between the carbon material and the active material or the current collector. It was found that an effect can be obtained. This effect was particularly remarkable when the polymer dispersant had a hydroxyl group. Although this principle is not clear, it was considered that a strong intermolecular force such as a hydrogen bond was applied to the polymer dispersant.

  That is, the present invention relates to a dispersant containing a triazine derivative having an acidic functional group represented by the following general formula (1) and an amine or an inorganic base.

［一般式（１）中、Ｒ¹は、少なくとも−NHC（＝O）−を含む置換基を有するフェニル基、ベンゾイミダゾール基、置換基を有してもよいインドール基または置換基を有してもよいピラゾール基を表す。ここで、−NHC（＝O）−を含む置換基を有するフェニル基の前記置換基は、少なくとも１つは以下の構造を有する置換基である。ただし、＊印はベンゼン環との結合部分を表す。］

[In General Formula (1), R ¹ has a phenyl group having a substituent containing at least —NHC (═O) —, a benzimidazole group, an indole group which may have a substituent, or a substituent. Represents a good pyrazole group. Here, at least one of the substituents of the phenyl group having a substituent containing —NHC (═O) — is a substituent having the following structure. However, * mark represents the bonding part with the benzene ring. ]

  Moreover, this invention relates to the dispersing agent whose content of the amine with respect to a triazine derivative is 0.1-5 molar equivalent.

  Moreover, this invention relates to the dispersing agent whose content of the amine with respect to a triazine derivative is 0.3-2 molar equivalent.

  Moreover, this invention relates to the dispersing agent whose content of the inorganic base with respect to a triazine derivative is 0.1-1 molar equivalent.

  The present invention also relates to a dispersion composition comprising the dispersant, a carbon material, and a solvent.

  The present invention further relates to a dispersion composition comprising a polymer dispersant.

  The present invention also relates to a dispersion composition in which the polymer dispersant has a hydroxyl group.

  The present invention also relates to a dispersion composition in which the polymer dispersant is a polyvinyl alcohol resin and / or a cellulose resin.

  The present invention further relates to a dispersion composition comprising a binder.

  The present invention further relates to a battery dispersion composition comprising an active material.

Moreover, this invention relates to the said dispersion composition for batteries whose addition amount of a dispersing agent is 0.1-200 mg with respect to 1 m < ² > of active material surface areas.

  Moreover, this invention relates to the electrode which has the mixture layer formed from the said dispersion composition for batteries on a collector.

  The present invention also relates to a battery comprising the electrode and a non-aqueous electrolyte.

  The present invention also relates to a battery in which the amount of the dispersant with respect to 1 ml of the non-aqueous electrolyte is 10 μg to 60 mg.

  According to the present invention, it is possible to provide a battery having lower ionic resistance and reaction resistance than in the case of using a conventionally known dispersion composition and excellent in rate characteristics and low temperature characteristics. Moreover, the combined use with a polymer dispersing agent provides the synergistic effect which improves adhesiveness (peeling strength) specifically.

  Hereinafter, the present invention will be described in detail.

<Dispersant>
One embodiment of the present invention is a dispersion composition comprising a triazine derivative represented by the general formula (1), a dispersant containing an amine or an inorganic base, a carbon material, and a solvent.

In general formula (1), R ¹ may have a phenyl group having a substituent containing at least —NHC (═O) —, a benzimidazole group, an indole group which may have a substituent, or a substituent. Represents a good pyrazole group.

Examples of the substituent containing —NHC (═O) — of R ¹ include the following structures. However, * mark represents the bonding part with the benzene ring.

  In addition, a phenyl group having a substituent containing at least —NHC (═O) — has, as other substituents, a halogen group such as a methyl group, a trifluoromethyl group, a methoxy group, an ethoxy group, fluorine, and chlorine. You may do it. Moreover, there may be a plurality of these substituents.

Examples of the substituent of the indole group which may have a substituent of R ¹ or the pyrazole group which may have a substituent include a methyl group.

  Furthermore, examples of the amine added together with the triazine derivative include primary, secondary, and tertiary alkyl amines having 1 to 40 carbon atoms.

  Examples of the primary alkylamine having 1 to 40 carbon atoms include propylamine, butylamine, isobutylamine, octylamine, 2-ethylhexylamine, laurylamine, stearylamine, oleylamine, 2-aminoethanol, 3-aminopropanol, and 3-ethoxy. Examples include propylamine and 3-lauryloxypropylamine.

  Examples of the secondary alkylamine having 1 to 40 carbon atoms include dibutylamine, diisobutylamine, N-methylhexylamine, dioctylamine, distearylamine, and 2-methylaminoethanol.

  Examples of the tertiary alkylamine having 1 to 40 carbon atoms include triethylamine, tributylamine, N, N-dimethylbutylamine, N, N-diisopropylethylamine, dimethyloctylamine, trioctylamine, dimethyldecylamine, dimethyllaurylamine, dimethylmyristyl. Examples include amine, dimethyl palmitylamine, dimethylstearylamine, dilauryl monomethylamine, triethanolamine, and 2- (dimethylamino) ethanol.

  Of these, primary, secondary or tertiary alkylamines having 1 to 30 carbon atoms are preferred, and primary, secondary or tertiary alkylamines having 1 to 20 carbon atoms are more preferred.

  The addition amount of the amine used in the present invention is not particularly limited, but is preferably 0.1 molar equivalent or more and 5 molar equivalent or less with respect to the triazine derivative represented by the general formula (1). It is more preferably 3 molar equivalents or more and 2 molar equivalents or less.

  The amine can be added during the production of the dispersant and / or during the production of the dispersion composition.

  Examples of the inorganic base added together with the triazine derivative include alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal phosphates, alkaline earths Examples thereof include metal phosphates.

  Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.

  Examples of the alkaline earth metal hydroxide include magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide.

  Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

  Examples of the alkaline earth metal carbonate include magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate.

  Examples of the alkali metal phosphate include lithium phosphate, trisodium phosphate, disodium hydrogen phosphate, tripotassium phosphate, and dipotassium hydrogen phosphate.

  Examples of alkaline earth metal phosphates include magnesium phosphate, calcium phosphate, strontium phosphate, and barium phosphate.

  The addition amount of the inorganic base used in the present invention is not particularly limited, but is 0.1 mol or more and 1.0 mol or less with respect to 1 mol of the triazine derivative represented by the general formula (1). Preferably, 0.3 mol or more and 0.7 mol or less are more preferable.

  The inorganic base can be added during the production of the dispersant and / or during the production of the dispersion composition.

  The effect of this invention appears by using the dispersing agent containing the triazine derivative represented by the general formula (1) described above and an amine or an inorganic base.

The amount of the dispersant added is preferably 0.1 to 200 mg, more preferably 0.2 to 100 mg, and further preferably 0.5 to 50 mg with respect to 1 m ^{2 of} the active material surface area.

  Moreover, 10 micrograms-60 mg are preferable with respect to 1 ml of non-aqueous electrolyte, 50 micrograms-20 mg are more preferable, and 70 micrograms-15 mg are more preferable.

  The dispersant of the present invention can be suitably used as a dispersant for carbon materials such as carbon black used for batteries, capacitors and capacitors, but it can be used as a coloring composition for various inks, paints, color filter resists and the like. It can also be used as a dispersant for pigments used in the above.

<Polymer dispersant>
The dispersant in the present invention may be used in combination with one or more commonly used polymer dispersants for the purpose of adjusting film formability and film strength, or controlling rheology, or may be used in combination of two or more. .

  The polymer dispersant used in the present invention is a polyvinyl alcohol, a modified polyvinyl alcohol having a functional group other than a hydroxyl group, such as an acetyl group, a sulfo group, a carboxyl group, a carbonyl group, or an amino group, one modified with various salts, other anions Or a cation-modified one, an acetal-modified (acetoacetal-modified or butyral-modified, etc.) polyvinyl alcohol resin, various (meth) acrylic polymers, polymers derived from ethylenically unsaturated hydrocarbons, various cellulose types Although a polymer etc. and these copolymers can be used, it is not limited to these.

  If the average degree of polymerization of the polymer dispersant is too low, the adsorptive power to the dispersoid is weak, and if it is too high, not only does the viscosity deteriorate, but also it does not spread well in the dispersion and the dispersion stabilizing effect is reduced. The thing of 100-2000 is preferable, The thing of 200-1000 is further more preferable.

  The polyvinyl alcohol-based resin preferably has a hydroxyl group of 60 mol% or more, more preferably 75 mol% or more, and more preferably 80 mol% or more in order to have an appropriate affinity with the dispersoid, the dispersion solvent, and the electrolytic solution. Is more preferable.

  Examples of commercially available polyvinyl alcohol resins included in the range of the hydroxyl amount include, for example, Kuraray Poval (polyvinyl alcohol resin manufactured by Kuraray Co., Ltd.), Gohsenol, Gohsenx (polyvinyl alcohol resin manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Denka Poval (Denka Company) Various grades can be obtained under trade names such as “Polyvinyl alcohol resin” and “J-Poval” (polyvinyl alcohol resin manufactured by Nippon Vinegar-Poval). Moreover, the modified polyvinyl alcohol which has various functional groups can be obtained similarly.

  When synthesizing without using commercially available products, generally, vinyl acetate is polymerized to a predetermined degree of polymerization in a methanol solution, etc., and an alkali catalyst such as sodium hydroxide is added to the obtained polyvinyl acetate to saponify the reaction. It is known that polyvinyl alcohol having a controlled amount of hydroxyl group can be obtained.

  When synthesizing and using denatured polyvinyl alcohol, it is generally (meth) acrylic monomers such as (meth) acrylic acid, vinyl ester monomers, α-β unsaturated bonds and functional groups together with vinyl acetate in methanol solution etc. It is known that a modified polyvinyl alcohol with a controlled modification rate can be obtained by copolymerization of a monomer having saponification and the like and then a saponification reaction. In addition, a modified polyvinyl alcohol resin can be obtained by addition reaction or esterification reaction of an acid anhydride with the polyvinyl alcohol resin.

  As a commercially available polyvinyl acetal resin, various grades can be obtained under trade names such as Mobital (polyvinyl butyral resin manufactured by Kuraray Co., Ltd.) and Eslek (polyvinyl acetal or polyvinyl butyral manufactured by Sekisui Chemical Co., Ltd.). In order to obtain the above preferred hydroxyl group amount, it may be synthesized and used. As a general synthesis method, a polyvinyl acetal resin controlled to have a predetermined degree of acetalization can be obtained by reacting polyvinyl alcohol with an aldehyde. Moreover, if the carbon number of the aldehyde is changed, the carbon number of the acetal group can be arbitrarily selected.

  As the cellulose-based resin, cellulose, a cellulose whose hydroxyl group is partly modified with an alkyl group, a hydroxyalkyl group or a carboxyalkyl group or a salt thereof can be used. For example, Metrols (methyl cellulose manufactured by Shin-Etsu Chemical Co., Ltd.) , Or hydroxypropylmethylcellulose), Meserose (water-soluble cellulose ether, Sakai Kogyo Co., Ltd., hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, methylcellulose), Sunrose (Carbomethylmethylcellulose sodium, Nippon Paper Industries Co., Ltd.) Various grades can be obtained under trade names such as Daicel CMC (Carbomethylmethylcellulose sodium manufactured by Daicel Finechem). In particular, methyl cellulose and ethyl cellulose are preferable from the viewpoints of solubility in an electrolytic solution and swelling properties.

<Carbon material>
The carbon material used in the present invention is not particularly limited, but when used as a carbon material for a battery, graphite, carbon black, carbon nanotube, carbon nanofiber, carbon fiber, graphene, fullerene, etc. are used alone. Or two or more types are preferably used in combination. When used as a carbon material, carbon black is preferably used from the viewpoint of conductivity, availability, and cost.

  As the carbon black used in the present invention, various types such as commercially available furnace black, channel black, thermal black, acetylene black, and ketjen black can be used alone or in combination of two or more. Ordinarily oxidized carbon black, hollow carbon and the like can also be used. The carbon black has a particle diameter of preferably 0.01 to 1 μm, more preferably 0.01 to 0.2 μm. As used herein, the particle size refers to the average primary particle size measured with an electron microscope, and the physical property values are generally used to represent the physical characteristics of carbon black.

  The carbon nanotube used in the present invention is a carbon material having a shape in which graphene is wound in a cylindrical shape. The diameter obtained by observation with an electron microscope is about several nm to 100 nm, and the length is about several nm to 1 mm. is there. In order to exhibit semiconductor characteristics, transparency of the coating film, etc., the diameter is preferably 50 nm or less, particularly preferably 20 nm or less. The length is preferably from 100 nm to 1 mm, particularly preferably from 500 nm to 1 mm. There are single-walled carbon nanotubes and multi-walled carbon nanotubes, but any structure may be used. In addition, fibers having a fiber diameter of about 100 nm to about 1 μm, which are classified as carbon nanofibers and obtained by observation with an electron microscope, can be used.

  The graphene used in the present invention is a monoatomic thin film constituting graphite, which is a carbon material in which carbon atoms are arranged in a honeycomb lattice (hexagonal shape) on a plane, and includes multilayered graphene that is laminated. As the multilayer graphene, graphene having 2 to 50 graphene layers can be used.

<Solvent>
As a solvent used in the present invention, one of an aprotic polar solvent, a water-soluble polar solvent and water may be used alone, or two or more may be used in combination. As the aprotic polar solvent, an amide solvent is preferable, and in particular, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2 -Use of amide type aprotic solvents such as pyrrolidone and hexamethylphosphoric triamide is preferred. The water-soluble polar solvent is preferably an alcohol, ester, ether, glycol, glycol ester, or glycol ether. Water may be used alone, or in order to improve the wettability and coating properties of the carbon material, a small amount of a water-soluble polar solvent having a low surface tension may be used in combination, especially propylene glycol monoethyl ether, ethylene Use in combination with glycol dimethyl ether, diethylene glycol methyl ethyl ether, dipropylene glycol dimethyl ether, propylene glycol monopropyl ether, and N-methyl-2-pyrrolidone is preferred.

<Binder>
The binder to be used is not particularly limited, but ethylene, propylene, vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylonitrile, styrene, vinyl butyral, vinyl acetal, Polymer or copolymer containing vinylpyrrolidone as a structural unit, polyurethane resin, polyester resin, phenol resin, epoxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, acrylic resin, formaldehyde resin, silicon resin, fluorine resin And cellulose resins such as carboxymethyl cellulose, rubbers such as styrene-butadiene rubber and fluororubber, and conductive resins such as polyaniline and polyacetylene. Moreover, the modified body and copolymer of these resin may be sufficient. In particular, when used in battery applications, it is preferable to use a polymer compound containing a fluorine atom in the molecule, for example, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene, etc. from the viewpoint of resistance. These binders can be used alone or in combination. When water is used as the solvent, it is preferable to use a combination of an emulsion such as a polymer compound containing fluorine atoms or styrene-butadiene rubber and carboxymethyl cellulose that also functions as a thickener.

<Active material>
The active material is a substance that stores or discharges with an oxidation-reduction reaction in the battery. Examples include a positive electrode active material used for a positive electrode and a negative electrode active material used for a negative electrode.

<Positive electrode active material>
The positive electrode active material to be used is not particularly limited as long as it functions as a battery active material. For example, when used in a lithium ion secondary battery, metal oxides capable of doping or intercalating lithium ions, metal compounds such as metal sulfides, conductive polymers, and the like can be used.

Specifically, lithium manganese composite oxide (for example, Li _x Mn ₂ O ₄ or Li _x MnO ₂ ), lithium nickel composite oxide (for example, Li _x NiO ₂ ), lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel cobalt composite oxide (e.g., _{Li x Ni 1-y Co y} O 2), lithium manganese cobalt composite oxides (e.g., _{Li x Mn y Co 1-y} O 2), lithium nickel manganese cobalt composite oxide (e.g., Li _{x Ni y Co z Mn 1-} y-z O 2), spinel type lithium-manganese-nickel composite oxide (e.g., _{Li x Mn 2-y Ni y} O 4) a composite oxide of lithium and a transition metal, such as powders, olivine Lithium phosphorus oxide powder having a structure (for example, Li _x FePO ₄ , Li _x Fe _1-y Mn _y PO _{4, Li} x etc. CoPO _4), manganese oxide, iron oxide, copper oxide, nickel oxide, vanadium oxide (e.g. _{V 2 O 5, V 6 O} 13), a transition metal oxide powder such as titanium oxide, sulfate Examples thereof include transition metal sulfide powders such as iron (Fe ₂ (SO ₄ ) ₃ ), TiS ₂ , and FeS. However, x, y, and z are numbers, and 0 <x <1, 0 <y <1, 0 <z <1, and 0 <y + z <1. In addition, conductive polymers such as polyaniline, polyacetylene, polypyrrole, and polythiophene can also be used. These positive electrode active materials can be used alone or in combination.

<Negative electrode active material>
There are no particular limitations on the negative electrode active material to be used, lithium ion doping or capable of intercalating Li metal or its alloy, tin alloy, a silicon alloy negative _{electrode, Li X TiO 2, Li X} Fe 2 O 3, Li _{X Fe 3 O 4, Li X} WO 2 or the like of the metal oxide-based, polyacetylene conductive polymers poly -p- phenylene, or amorphous-based carbon material such as soft carbon or hard carbon, highly graphitized carbon material or the like Carbonaceous materials such as artificial graphite or natural graphite, carbon black, mesophase carbon black, resin-fired carbon material, air-growth carbon fiber, carbon fiber and the like are used. However, x is a number and 0 <x <1. These negative electrode active materials can be used alone or in combination.

<Dispersion composition>
As described above, the dispersion composition of the present invention is a carbon material dispersion containing the above dispersant, carbon material, solvent, or carbon material dispersion varnish further containing a binder, and is required to have uniform and good coating film properties. Can be used in the fields of printing inks, paints, plastics, toners, color filter resist inks, batteries and the like. In particular, since a coating film suitable for an electrode layer having a uniform and good coating film property and a low surface resistance can be provided, it can be suitably used in an application for forming a battery electrode. You may use for the base layer provided between a collector and a mixture layer.

<Method for producing dispersion composition>
The carbon material dispersion which is the dispersion composition of the present invention can be produced by mixing the dispersant, the carbon material, and a solvent. The carbon material-dispersed varnish can be produced by mixing the dispersant, the carbon material, a solvent, and a binder. The order of addition of each component is not limited. For example, the carbon material dispersion is (1) a method in which all components are mixed and dispersed at once, and (2) a solvent in which a dispersant is previously dispersed and dissolved. Examples thereof include a method of dispersing a carbon material. The carbon material dispersion varnish includes (1) a method of mixing, dispersing, and dissolving all components at once, (2) a method of mixing and dissolving a binder powder after preparing a carbon material dispersion in advance, and (3) Examples thereof include a method of mixing a binder solution after preparing a carbon material dispersion. Moreover, you may add the above-mentioned solvent further as needed.

  As the mixing / dispersing / dissolving apparatus, a disperser usually used for pigment dispersion or the like can be used. For example, mixers such as dispersers, homomixers, planetary mixers, homogenizers (such as “Clairemix” manufactured by M Technique, “Fillmix” manufactured by PRIMIX, “Abramix” manufactured by Silverson, etc.), paint conditioners ( Red Devil), colloid mill ("PUC colloid mill" manufactured by PUC, "colloid mill MK" manufactured by IKA), cone mill ("Cone mill MKO" manufactured by IKA), ball mill, sand mill (Shinmaru Enterprises) "Dynomill", etc.), Attritor, Pearl Mill ("DCP Mill" manufactured by Eirich), Coball Mill and other media type dispersers, Wet Jet Mill ("Genus PY" manufactured by Genus, "Starburst" manufactured by Sugino Machine "Nanomizer" manufactured by Nanomizer ), M Technique Co., Ltd. "Claire SS-5", Nara Machinery Co., Ltd. "MICROS" media-less dispersing machine such as, but other roll mill, and the like, but is not limited to these.

  Moreover, as the disperser, it is preferable to use a disperser that has been subjected to a metal contamination prevention treatment from the disperser. For example, when using a media-type disperser, a metal agitator and vessel are made of ceramic or resin dispersers, or the metal agitator and vessel surface are coated with tungsten carbide spray or resin coating. It is preferable to use a disperser that has been treated as described above. As the medium, glass beads, ceramic beads such as zirconia beads or alumina beads are preferably used. Moreover, also when using a roll mill, it is preferable to use a ceramic roll. Only one type of disperser may be used, or a plurality of types of devices may be used in combination.

<Dispersion composition for battery>
The battery dispersion composition of the present invention is a battery dispersion composition (hereinafter referred to as “mixture paste”) in which an active material is contained in a dispersion composition containing the dispersant, carbon material, solvent, and binder. It is preferable to use it.

  This mixture paste can be produced by mixing the dispersant, the carbon material, the solvent, the binder, and the active material. The order of addition of each component is not limited. For example, a method of mixing all components at once, a method of adding the remaining components to the carbon material dispersion prepared in advance by the above method, and mixing, For example, the active material is added to the carbon material-dispersed varnish prepared in advance by the above method and mixed. Moreover, you may add the above-mentioned solvent further as needed.

  As an apparatus for producing the mixture paste, the same apparatus as that used when producing the above-described dispersion composition of the present invention can be used.

<Battery>
Next, a battery using the composition of the present invention will be described. The composition of the present invention can be suitably used particularly for a lithium ion secondary battery. Hereinafter, a lithium ion secondary battery will be described, but a battery using the composition of the present invention is not limited to a lithium ion secondary battery.

  A lithium ion secondary battery includes a positive electrode having a positive electrode mixture layer on a current collector, a negative electrode having a negative electrode mixture layer on the current collector, and a non-aqueous electrolyte composed of an electrolyte containing lithium. .

  Regarding the electrode, the material and shape of the current collector to be used are not particularly limited, and as the material, metals and alloys such as aluminum, copper, nickel, titanium, and stainless steel are used. In particular, as the positive electrode material, aluminum is used as the negative electrode. The material is preferably copper. As the shape, a flat plate foil is generally used, but a roughened surface, a perforated foil shape, and a mesh shape can also be used. The current collector may be provided with a conductive underlayer for the purpose of improving contact resistance and adhesion (peeling strength) between the current collector and the mixture layer.

  The mixture layer can be formed by directly applying the mixture paste on the current collector and drying it. The thickness of the mixture layer is generally 1 μm or more and 1 mm or less, preferably 100 μm or more and 500 μm or less. There is no restriction | limiting in particular about the coating method, A well-known method can be used. Specific examples include a die coating method, a dip coating method, a roll coating method, a doctor coating method, a spray coating method, a gravure coating method, a screen printing method, and an electrostatic coating method. Moreover, you may perform the rolling process by a lithographic press, a calender roll, etc. after application | coating.

As an electrolytic solution constituting the lithium ion secondary battery, a solution in which an electrolyte containing lithium is dissolved in a non-aqueous solvent is used. As the electrolyte, LiBF ₄ , LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₃ C , LiI, LiBr, LiCl, LiAlCl, LiHF ₂ , LiSCN, LiBPh ₄ (where Ph is a phenyl group) and the like, but are not limited thereto.

  The non-aqueous solvent is not particularly limited, but carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, γ-butyrolactone, γ-valerolactone, γ-octanoic lactone. Lactones such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,2-methoxyethane, 1,2-ethoxyethane, 1,2-dibutoxyethane, etc. Glymes, esters such as methyl formate, methyl acetate, and methyl propionate, sulfoxides such as dimethyl sulfoxide and sulfolane, nitriles such as acetonitrile, and N-methyl-2-pyrrolidone . These solvents may be used alone or in combination of two or more. In particular, a mixture of ethylene carbonate with a high dielectric constant and high electrolyte dissolving power and other solvents is preferable. Further, as other solvents, linear carbonates such as propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate are preferred. A system solvent is more preferable.

  Furthermore, the electrolyte solution may be a gelled polymer electrolyte held in a polymer matrix. Examples of the polymer matrix include, but are not limited to, an acrylate resin having a polyalkylene oxide segment, a polyphosphazene resin having a polyalkylene oxide segment, a polysiloxane having a polyalkylene oxide segment, and the like.

  The structure of the battery using the composition of the present invention is not particularly limited, but is usually composed of a positive electrode and a negative electrode, and a separator provided as necessary, and is a paper type, a cylindrical type, a square type, a button type, a laminate. Various shapes can be formed according to the purpose of use, such as a mold and a wound mold.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to a following example, unless the summary is exceeded. In addition, in order to clarify the difference between individual compositions, a dispersion composition comprising a dispersant, a carbon material, and a solvent is referred to as a “carbon material dispersion”, and a dispersion composition comprising a dispersant, a carbon material, a solvent, and a binder. A battery dispersion composition comprising “carbon material dispersion varnish”, a dispersant, a carbon material, a solvent, a binder, and an active material is referred to as “mixture paste”. Unless otherwise specified, N-methyl-2-pyrrolidone used as a solvent is abbreviated as “NMP”, and mass% is abbreviated as “%”.

<Dispersant>
The structures of triazine derivatives A to Y represented by the general formula (1) of the present invention are shown below. The method for producing the triazine derivatives A to Y represented by the general formula (1) used in the present invention is not particularly limited, and a known method can be applied. For example, the method described in JP 2004-217842 A can be applied. The disclosure by the above publication is incorporated into a part of this specification by reference.

<Method for producing dispersant comprising triazine derivative and amine>
Dispersants a to ao listed in Table 1 were produced by the methods described in the following examples.

[Example 1-1]
(Production of Dispersant a)
0.040 mol of triazine derivative A was added to 200 g of water. 0.040 mol of octylamine was added to this, and it stirred at 60 degreeC for 2 hours. After cooling to room temperature, filtration purification was performed. The obtained residue was dried at 90 ° C. for 48 hours to obtain Dispersant a.

[Examples 1-2 to 1-25]
(Production of dispersants b to y)
The dispersant a was prepared in the same manner as in Example 1-1 except that instead of the triazine derivative A, the triazine derivatives B to Y described in Examples 1-2 to 1-25 in Table 1 were added. Dispersants b to y were obtained.

[Examples 1-26 to 1-36]
(Production of dispersants z to aj)
The dispersant b was prepared in the same manner as in Example 1-2 except that the amine described in Examples 1-26 to 1-36 in Table 1 was added instead of octylamine in the manufacture of the dispersant b. aj was obtained.

[Examples 1-37 to 1-41]
(Production of dispersants ak to ao)
The dispersant b was produced in the same manner as in Example 1-2 except that the amount of octylamine added was changed to the amount described in Examples 1-37 to 1-41 in Table 1, and the dispersant ak ~ Ao was obtained.

  The structures of triazine derivatives AA to AC used in the comparative examples are shown below. The method for producing the triazine derivatives AA to AC used in the comparative examples is not particularly limited, and a known method can be applied. For example, the method described in JP 2004-217842 A can be applied. The disclosure by the above publication is incorporated into a part of this specification by reference.

  Dispersants ba to bc listed in Table 2 were produced by the method described in the following comparative examples.

[Comparative Examples 1-1 to 1-3]
(Production of dispersants ba to bc)
The dispersant a was prepared in the same manner as in Example 1-1 except that the triazine derivatives AA to AC described in Comparative Examples 1-1 to 1-3 in Table 2 were added instead of the triazine derivative A. Dispersants ba-bc were obtained.

<Method for producing dispersant composed of triazine derivative and inorganic base>
Dispersants ca to di listed in Table 3 were produced by the methods described in the following examples.

[Example 2-1]
(Production of dispersant ca)
0.040 mol of triazine derivative A was added to 200 g of water. 0.020 mol of sodium hydroxide was added to this, and it stirred at 60 degreeC for 2 hours. After cooling to room temperature, filtration purification was performed. The obtained residue was dried at 90 ° C. for 48 hours to obtain a dispersant ca.

[Examples 2-2 to 2-25]
(Production of dispersants cb to cy)
The dispersant ca was prepared in the same manner as in Example 2-1, except that the triazine derivatives BY described in Examples 2-2 to 2-25 in Table 3 were added instead of the triazine derivative A. Dispersants cb to cy were obtained.

[Examples 2-26 to 2-31]
(Production of dispersants cz to de)
The dispersant cb was prepared in the same manner as in Example 2-2 except that the inorganic base described in Examples 2-26 to 2-31 in Table 3 was added instead of sodium hydroxide. cz to de were obtained.

[Examples 2-32 to 2-35]
(Production of dispersants df to di)
The dispersant cb was produced in the same manner as in Example 2-2 except that the amount of sodium hydroxide added was changed to the amount described in Examples 2-32 to 2-35 in Table 3, and the dispersant was df-di were obtained.

  Dispersants ea to ec listed in Table 4 were produced by the method described in the following comparative examples.

[Comparative Examples 2-1 to 2-3]
(Production of dispersants ea to ec)
The dispersant ca was prepared in the same manner as in Example 2-1, except that the triazine derivatives AA to AC described in Comparative Examples 2-1 to 2-3 in Table 4 were added instead of the triazine derivative A. Dispersants ea to ec were obtained.

  The carbon material dispersions, carbon material dispersion varnishes, and mixture pastes shown in Examples and Comparative Examples were prepared using the materials shown below.

<Carbon material>
DENKA BLACK HS100 (manufactured by DENKA CORPORATION): acetylene black, average primary particle diameter determined by observation with an electron microscope of 48 nm, specific surface area determined by S-BET formula from nitrogen adsorption amount is 39 m ² / g, hereinafter “HS100” Abbreviated.
super-P (manufactured by TIMCAL): furnace black, the average primary particle diameter determined by observation with an electron microscope is 40 nm, and the specific surface area determined by the S-BET formula from the amount of nitrogen adsorption is 62 m ² / g.
Monarch 800 (manufactured by Cabot Corporation): Furnace black, the average primary particle diameter determined by observation with an electron microscope is 17 nm, the specific surface area determined by the S-BET formula from the nitrogen adsorption amount is 210 m ² / g, hereinafter “M800” Abbreviated.
EC-300J (manufactured by Lion Specialty Chemicals): Ketjen black, average primary particle size determined by observation with an electron microscope of 40 nm, specific surface area determined by S-BET formula from nitrogen adsorption amount is 800 m ² / g .
Carbon nanotube: Multi-walled carbon nanotube, fiber diameter of 10 nm obtained by observation with an electron microscope, fiber length of 2 to 5 μm, specific surface area of 600 m ² / g obtained from the amount of nitrogen adsorption by the S-BET equation, hereinafter abbreviated as CNT.
VGCF (manufactured by Showa Denko KK): carbon nanofiber, fiber diameter 150 nm, fiber length 10-20 μm determined by observation with an electron microscope.

<Binder>
KF polymer W1100 (manufactured by Kureha): polyvinylidene fluoride (PVDF), hereinafter abbreviated as PVDF.
Polytetrafluoroethylene emulsion: (Mitsui / Dupont Fluorochemical Co., Ltd.), hereinafter abbreviated as PTFE.
Carboxymethylcellulose (manufactured by Nippon Paper Industries Co., Ltd.): hereinafter abbreviated as CMC.

<Positive electrode active material>
LiNi _1/3 Mn _1/3 Co _1/3 O ₂ (manufactured by Toda Kogyo Co., Ltd.): positive electrode active material, nickel manganese lithium cobaltate, average primary particle size determined by observation with an electron microscope is 5.0 μm, nitrogen adsorption The specific surface area determined by the S-BET formula from the amount is 0.62 m ² / g, hereinafter abbreviated as NMC.
HLC-22 (Honjo Chemical Co., Ltd.): Positive electrode active material, lithium cobaltate (LiCoO ₂ ), average primary particle size determined by observation with an electron microscope was 6.6 μm, determined from the amount of nitrogen adsorption by the S-BET equation Specific surface area is 0.62 m ² / g, hereinafter abbreviated as LCO.
LiNi _0.8 Co _0.15 Al _0.05 O ₂ (manufactured by Sumitomo Metals): positive electrode active material, nickel cobalt lithium aluminate, average primary particle size determined by observation with an electron microscope is 5.8 μm, nitrogen adsorption The specific surface area determined from the amount by the S-BET equation is 0.38 m ² / g, hereinafter abbreviated as NCA.
LiFePO ₄ (manufactured by Clariant): positive electrode active material, lithium iron phosphate, average primary particle diameter determined by observation with an electron microscope is 0.4 μm, specific surface area determined by S-BET formula from nitrogen adsorption amount is 15. 3 m ² / g, hereinafter abbreviated as LFP.

<Negative electrode active material>
Spherical graphite (manufactured by Nippon Graphite Co., Ltd.): negative electrode active material, primary particle diameter determined by observation with an electron microscope is 15 μm, specific surface area determined by S-BET formula from nitrogen adsorption amount is 1.0 m ² / g, hereinafter spherical Abbreviated as graphite.

<Polymer dispersant>
PVA-103 (manufactured by Kuraray Co., Ltd.): polyvinyl alcohol, saponification degree 98.0-99.0 mol%, average polymerization degree 300
PVA-403 (manufactured by Kuraray Co., Ltd.): polyvinyl alcohol, saponification degree 78.5-81.5 mol%, average polymerization degree 300
KL-506 (manufactured by Kuraray Co., Ltd.): anion-modified polyvinyl alcohol, saponification degree 74.0-80.0 mol%, polymerization degree 600
Gohsenx L-3266 (manufactured by Nippon Synthetic Chemical Co., Ltd.): sulfonic acid-modified polyvinyl alcohol, saponification degree 86.5-89.0 mol% (hereinafter abbreviated as L-3266)
Gohsenx K-434 (manufactured by Nippon Synthetic Chemical Co., Ltd.): cation-modified polyvinyl alcohol, saponification degree 85.5-88.0 mol% (hereinafter abbreviated as K-434)
Polyvinyl butyral A: polyvinyl butyral, degree of butyralization 15 mol%, hydroxyl group amount 84 mol%, acetic acid group 1 mol%, polymerization degree 300 (hereinafter abbreviated as PVB-A)
Metrows SM-15 (manufactured by Shin-Etsu Chemical Co., Ltd.): methyl cellulose, substitution degree 1.8, viscosity of 2% aqueous solution at 20 ° C., about 15 mPa · s (hereinafter abbreviated as SM-15)
Etcello 10 (Dow Chemical Co.): Viscosity of ethyl cellulose, 5% toluene / ethanol (8/2) solution at 25 ° C. 9.0 to 11.0 mPa · s

Synthesis of PVB-A (Synthesis Example) A 10% aqueous solution of PVA-103 was prepared, and 0.2 parts by mass of hydrochloric acid and 2 parts by mass of butyraldehyde were added dropwise to 100 parts by mass of the aqueous solution while stirring. Subsequently, the temperature was raised to 80 ° C., held for 1 hour, and then allowed to cool. This was dried and pulverized to obtain PVB-A having an acetalization degree of 15 mol%.

[Example 3-1]

<Preparation of carbon material dispersion>
In accordance with the composition shown in Table 5, N-methyl-2-pyrrolidone and dispersant a were charged into a glass bottle and mixed, then a carbon material was added, and zirconia beads were used as a medium and dispersed with a paint conditioner for 2 hours. A carbon material dispersion containing was obtained.

<Preparation of carbon material dispersion varnish>
According to the composition shown in Table 5, the carbon material dispersion containing the prepared dispersant a, a binder, and N-methyl-2-pyrrolidone were mixed with a disper to obtain a carbon material-dispersed varnish.

<Preparation of positive electrode mixture paste>
According to the composition shown in Table 5, the prepared carbon material dispersion varnish containing the dispersant a, the active material, and N-methyl-2-pyrrolidone were mixed with a disper to obtain a positive electrode mixture paste.

<Production of electrode>
After coating the prepared positive electrode mixture paste containing the dispersant a on a 20 μm-thick aluminum foil using a doctor blade, it was dried at 120 ° C. for 30 minutes under reduced pressure, and rolled with a roller press. An electrode having a coating amount of 17 mg / cm ² and a density of 3.0 g / cm ³ was produced. An electrode having a uniform thickness and density was obtained.

<Assembly of lithium ion secondary battery positive electrode evaluation cell>
The produced electrode containing the dispersant a was punched out to a diameter of 16 mm as a positive electrode, a metallic lithium foil (thickness 0.15 mm) as a negative electrode, and a separator (thickness 20 μm, pores) made of a porous polypropylene film between the positive electrode and the negative electrode 50%) is inserted and laminated, and 0.1 ml of electrolyte (nonaqueous electrolyte in which LiPF ₆ is dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate are mixed at a volume ratio of 1: 1) is filled. A bipolar sealed metal cell (HS flat cell manufactured by Hosen Co., Ltd.) was assembled. The cell was assembled in a glove box substituted with argon gas.

[Examples 3-2 to 3-76] Comparison of dispersant types-1
A positive electrode evaluation cell is assembled by dispersing in the same composition and method as in Example 3-1, except that the dispersants b to ao and ca to di shown in Table 6 are used instead of the dispersant a. It was.

[Comparative Examples 3-1 to 3-7] Comparison of dispersant types-2
A positive electrode evaluation cell was assembled by dispersing in the same manner as in Example 3-1, except that the dispersants ba to bc and ea to ec shown in Table 7 were used. However, in Comparative Example 3-7, no dispersant was used, and the composition was changed to a solvent.

<Ion resistance evaluation>
The positive electrode evaluation cells assembled in Examples 3-1 to 3-76 and Comparative Examples 3-1 to 3-7 were allowed to stand in a thermostatic bath at −20 ° C. for 12 hours, and the frequency was 0.1 Hz at an open circuit potential. performs AC impedance measurement with amplitude 10 mV, ionic resistance _| sought _{ion | Z.} Subsequently, the positive electrode evaluation cell was moved to room temperature (25 ° C.) and allowed to stand for 3 hours, and the impedance was measured in the same manner to obtain the _ion resistance | Z | An impedance analyzer was used for the measurement.

<Evaluation of reaction resistance>
Subsequent to the ionic resistance evaluation, using a charge / discharge measuring device, the battery is fully charged with a constant current and constant voltage charge of 0.1 C (upper limit voltage 4.2 V) at room temperature, and a discharge lower limit voltage of 3. A total of 5 cycles were performed, with 1 cycle being a charge / discharge cycle for discharging to 0V. The 0.1 C discharge capacity at the fifth cycle was recorded. Next, the positive electrode evaluation cell in a state discharged to 3.0 V was connected to an impedance analyzer, and AC impedance measurement was performed at 3.0 V, an amplitude of 10 mV, and a frequency of 0.1 Hz to 1 MHz. When the result is plotted on the complex plane by the Cole-Cole plot method, a semicircular curve is obtained. The diameter of this arc was defined as the reaction resistance | Z | _re of the active material.

<Evaluation of room temperature rate characteristics / low temperature discharge characteristics>
Next, after being fully charged at 0.1 C at room temperature, the battery was discharged at a constant current of 0.5 C to a discharge lower limit voltage of 3.0 V, fully charged again at 0.1 C and then at a constant current of 5 C The battery was discharged to 3.0V. The ratio of the 5C discharge capacity to the 0.1C discharge capacity at the fifth cycle recorded in the reaction resistance evaluation test was defined as the room temperature rate characteristic (%). Here, the 0.5 C discharge capacity at room temperature was recorded. Subsequently, the battery was fully charged at room temperature and 0.1 C in the same manner, then transferred to a −20 ° C. constant temperature bath and allowed to stand for 12 hours, and then discharged at a constant current of 0.5 C. The ratio of the 0.5 C discharge capacity at −20 ° C. to the 0.5 C discharge capacity at room temperature was defined as the low temperature discharge characteristic (%). Both room temperature rate characteristics and low-temperature discharge characteristics are better as they are closer to 100%.

<Evaluation results>
The carbon material dispersions, carbon material dispersion varnishes, and positive electrode mixture pastes described in Examples 3-1 to 3-76 and Comparative Examples 3-1 to 3-6 are in a well dispersed state, and after 1 month There was no sedimentation or thickening. Comparative Example 3-7 using no dispersant had a considerably high viscosity and poor fluidity from the beginning, but was used for comparison as it was. Moreover, it was gel-like after one month passage.

  Tables 8-1 and 8-2 show the evaluation results of ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of the positive electrode evaluation cells of Examples 3-1 to 3-76 and Comparative Examples 3-1 to 3-7. Shown in

  As can be seen from Table 8, the positive electrodes of Examples 3-1 to 3-76 using dispersants a to ao and ca to di have room temperature and −20 ° C. ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics. In all, it was very excellent compared with the positive electrode of Comparative Example 3-7 which does not use a dispersing agent and Comparative Examples 3-1 to 3-6 using dispersing agents ba to bc and ea to ec.

It is considered that the dispersants a to ao and ca to di cause dielectric polarization due to the presence of Li ⁺ having an extremely high electron density in the vicinity, and have a high dielectric constant in the battery. As a result, the ion conductivity is improved, and the desolvation energy and solvation energy of Li ⁺ when the active material and Li react with each other are reduced. It seems that the characteristics are improved.

[Examples 4-1 to 4-5] [Comparative Examples 4-1 to 4-5] Comparison of carbon material types Carbon material dispersions shown in Table 9, carbon material dispersion varnishes shown in Table 10, and Table 11 According to the material and composition of the positive electrode mixture paste shown, the positive electrode evaluation cell was assembled by dispersing in the same manner as in Example 3-1. Since a large amount of dispersant is necessary for the carbon material having a high specific surface area, the amount used was appropriately determined according to each carbon material.

Composition of carbon material dispersion

Composition of carbon material dispersion varnish

Composition of positive electrode mixture paste

<Evaluation results>
The carbon material dispersions, carbon material dispersion varnishes, and positive electrode mixture pastes described in any of the examples and comparative examples were also in a well dispersed state, and neither sedimentation nor thickening occurred after 1 month.

  Table 12 shows the evaluation results of the ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of the positive electrode evaluation cells of Examples 4-1 to 4-5 and Comparative Examples 4-1 to 4-5.

  The same effect could be confirmed with any carbon material. The difference between Examples 4-1 to 4-5 is considered to be a difference due to the conductivity of the carbon material. Moreover, in Comparative Examples 4-1 to 4-5, the more the amount of the dispersant added, the higher the resistance and the worse the characteristics.

  From the above verification, it was confirmed that the effects described above were not dependent on the carbon material type.

[Examples 5-1 to 5-6] Comparison of dispersant amount per active material surface area-1
A positive electrode evaluation cell was assembled in the same manner except that the dispersant amount shown in Table 13, Table 14, and Table 15 was used instead of the dispersant amount in Example 3-2. Table 16 shows the amount of the dispersant (mg) with respect to the active material surface area of 1 m ² in the electrode.

Composition of carbon material dispersion

Composition of carbon material dispersion varnish

Composition of positive electrode mixture paste

Dispersant amount per surface area of active material

<Evaluation results>
Table 17 shows the evaluation results of reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of Comparative Example 3-7, Example 3-2 and Examples 5-1 to 5-6.

  From Example 5-1, it turned out that an effect will become small when there are too few amounts of dispersing agents with respect to an active material surface area. Above the amount of the dispersant of Example 5-2, a particularly large effect can be obtained, and gradually improved as the amount of the dispersant increased.

[Examples 6-1 to 6-9] Comparison of dispersant amount per active material surface area-2
The materials and compositions shown in Table 18, Table 19, and Table 20 were dispersed in the same manner as in Example 3-2 to produce positive electrode evaluation cells. Table 21 shows the amount of the dispersing agent (mg) with respect to the active material surface area of 1 m ² in the electrode.

Composition of carbon material dispersion

Composition of carbon material dispersion varnish

Composition of positive electrode mixture paste

Dispersant amount per surface area of active material

<Evaluation results>
Table 22 shows the evaluation results of reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of Example 6-1 to Example 6-9.

  From Table 22, it was found that when the amount of the dispersant in Example 6-6 was exceeded, the reaction resistance reduction effect was reduced. When the amount of the dispersant is excessive, it is considered that the adverse effect as the resistance component becomes larger than the reduction of the desolvation energy.

  From the above, in order to obtain a greater reaction resistance reduction effect, it has been found that there is an optimum range of the dispersant addition amount relative to the active material surface area.

[Examples 7-1 to 7-6] Comparison of amount of dispersing agent with respect to amount of electrolyte-1
A positive electrode evaluation cell was assembled in the same manner as in Example 5-2, except that the amount of the electrolytic solution shown in Table 23 was changed using the positive electrode manufactured in Example 5-2.

[Examples 8-1 to 8-7] Comparison of dispersant amount with respect to electrolyte amount-2
A positive electrode was produced in the same manner as in Example 6-3, except that the coating amount was changed to 28 mg / cm ² using the positive electrode mixture paste produced in Example 6-3. Furthermore, the amount of the electrolytic solution added to the positive electrode evaluation cell was changed to the amount shown in Table 24, and the positive electrode evaluation cell was assembled in the same manner as in Example 6-3.

<Evaluation results>
Table 25 shows the evaluation results of the ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of Example 5-2, Examples 7-1 to 7-6, and Comparative Example 3-7. Table 26 shows the evaluation results of the ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of Examples 8-1 to 8-7.

  The reaction resistances of Example 5-2 and Examples 7-1 to 7-6 were the same. This is thought to be due to the equal amount of dispersant relative to the active material surface area.

  Moreover, in Examples 7-1 to 7-4, the ionic resistance at room temperature and low temperature was significantly lower than that of Comparative Example 3-7, and Examples 7-5 and 7- In 6, the effect was small. In order to obtain a great effect, it has been shown that there is a lower limit of the optimum amount of the dispersing agent with respect to the amount of the electrolyte.

  Since room temperature rate characteristics and low-temperature discharge characteristics are affected by both ionic resistance and reaction resistance, it is preferable to design so that both effects can be obtained in order to obtain excellent characteristics as a battery.

  On the other hand, from the comparison of Examples 8-1 to 8-7, it was found that the effect of reducing the ionic resistance is small even if the amount of the dispersant is too much with respect to the amount of the electrolytic solution. This is presumably because the dispersant is an insulating compound, so that if it is excessive, it itself becomes a resistance component.

  From the above, it has been found that there is an upper limit for the optimum amount of dispersant relative to the amount of electrolyte.

[Example 9-1] Investigation of influence of electrolyte solution LiPF ₆ was dissolved at a concentration of 1 M in the electrolyte solution used in Example 3-2 (a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1). Example 3 except that a nonaqueous electrolytic solution in which LiPF ₆ was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 2 was used instead of the nonaqueous electrolytic solution). As in -2, a positive electrode evaluation cell was assembled.

[Example 9-2]
Instead of the electrolytic solution used in Example 3-2 (nonaqueous electrolytic solution in which LiPF ₆ was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1), ethylene carbonate and A positive electrode in the same manner as in Example 3-2 except that a nonaqueous electrolytic solution in which LiPF ₆ was dissolved at a concentration of 1 M was used in a mixed solvent in which ethylmethyl carbonate and dimethyl carbonate were mixed at a volume ratio of 1: 1: 1. An evaluation cell was assembled.
[Comparative Example 9-1]
Instead of the electrolytic solution used in Comparative Example 3-7 (nonaqueous electrolytic solution in which LiPF ₆ was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1), ethylene carbonate and A positive electrode evaluation cell was assembled in the same manner as in Comparative Example 3-7, except that a nonaqueous electrolytic solution in which LiPF ₆ was dissolved at a concentration of 1 M was used in a mixed solvent in which diethyl carbonate was mixed at a volume ratio of 1: 2.

[Comparative Example 9-2]
Instead of the electrolytic solution used in Comparative Example 3-7 (nonaqueous electrolytic solution in which LiPF ₆ was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1), ethylene carbonate and A positive electrode as in Comparative Example 3-7, except that a non-aqueous electrolyte in which LiPF ₆ was dissolved at a concentration of 1 M was used in a mixed solvent in which ethyl methyl carbonate and dimethyl carbonate were mixed at a volume ratio of 1: 1: 1. An evaluation cell was assembled.

<Evaluation results>
Example 3-2, Example 9-1, Example 9-2, Comparative Example 3-7, Comparative Example 9-1, and Comparative Example 9-2 have ion resistance, reaction resistance, room temperature rate characteristics, and low-temperature discharge characteristics. The evaluation results are shown in Table 27.

  From Example 9-1 and Example 9-2, it was confirmed that all the characteristics were improved compared to the comparative example, regardless of the type of the electrolytic solution. In addition to the electrolytic solution shown in this example, it is considered that the same effect can be obtained regardless of the type of the nonaqueous electrolytic solution that is generally used.

  Next, the type of active material was changed and evaluated in the same manner.

[Examples 10-1 to 10-3] Comparison of Active Material Species Similar to Example 3-2 using the carbon material-dispersed varnish used in Example 3-2 and according to the active material and composition shown in Table 28 Then, a positive electrode evaluation cell was assembled.

[Comparative Examples 10-1 to 10-3]
Using the carbon material-dispersed varnish used in Comparative Example 3-1, it was dispersed in the same manner as in Comparative Example 3-1, according to the active material and composition shown in Table 28, and a positive electrode evaluation cell was assembled.

<Evaluation results>
Table 29 shows the evaluation results of the ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of Examples 10-1 to 10-3 and Comparative Examples 10-1 to 10-3.

  Although there are differences in battery characteristics depending on the performance of the active material, when Examples and Comparative Examples were compared with the same active material, it was confirmed that all of Examples 10-1 to 10-3 had improved characteristics. .

  Then, the evaluation at the time of using the dispersion composition of this invention for a negative electrode was performed.

[Example 11-1]

<Preparation of carbon material dispersion varnish>
According to the composition shown in Table 30, the carbon material dispersion containing the dispersant a prepared in Example 3-1 was mixed with a binder and N-methyl-2-pyrrolidone with a disper to obtain a carbon material-dispersed varnish.

<Preparation of negative electrode mixture paste>
According to the composition shown in Table 30, the prepared carbon material dispersion varnish containing dispersant a, the active material, and N-methyl-2-pyrrolidone were mixed with a disper to obtain a negative electrode mixture paste.

<Production of electrode>
After coating the prepared negative electrode mixture paste containing the dispersant a on a copper foil having a thickness of 20 μm using a doctor blade, it is dried at 120 ° C. for 30 minutes under reduced pressure, and is subjected to a rolling process by a roller press. An electrode having a coating amount of 15 mg / cm ² and a density of 1.8 g / cm ³ was produced. An electrode having a uniform thickness and density was obtained.

<Assembly of lithium ion secondary battery negative electrode evaluation cell>
The produced electrode containing the dispersant a was punched out to a diameter of 18 mm to form a negative electrode, a metal lithium foil (thickness 0.15 mm) as a positive electrode, and a separator (thickness 20 μm, pores) made of a porous polypropylene film between the negative electrode and the positive electrode 50%) is inserted and laminated, and 0.1 ml of electrolyte (nonaqueous electrolyte in which LiPF ₆ is dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate are mixed at a volume ratio of 1: 1) is filled. A bipolar sealed metal cell (HS flat cell manufactured by Hosen Co., Ltd.) was assembled. The cell was assembled in a glove box substituted with argon gas.

[Examples 11-2 to 11-76]
Using the carbon material dispersion liquid containing the dispersants b to ao and the dispersants ca to di produced in Examples 3-2 to 3-76, the carbon material was dispersed by the same composition and method as in Example 11-1. A dispersion varnish and a negative electrode mixture paste were prepared, and a negative electrode evaluation cell was assembled. Table 31 shows the correspondence between the carbon material dispersion used and the dispersant.

[Comparative Examples 11-1 to 11-7]
Using the carbon material dispersion liquids containing the dispersants ba to bc and the dispersants ea to ec prepared in Comparative Examples 3-1 to 3-7, the carbon material was dispersed by the same composition and method as in Example 11-1. A dispersion varnish and a negative electrode mixture paste were prepared, and a negative electrode evaluation cell was assembled. However, Comparative Example 11-7 did not use a dispersant, and the composition was changed to a solvent. Table 32 shows the correspondence between the carbon material dispersion used and the dispersant.

<Ion resistance evaluation>
Impedance was measured under the same conditions as in Example 3-1, and the ionic resistance | Z | _ion at −20 ° C. and room temperature (25 ° C.) was determined.

<Evaluation of reaction resistance>
Subsequent to the ionic resistance evaluation, using a charge / discharge measuring device, the battery is fully charged at a constant current and constant voltage of 0.1 C (lower limit voltage 0.0 V) at room temperature, and the discharge upper limit voltage is 2. A total of 5 cycles were performed, with 1 cycle being a charge / discharge cycle for discharging to 0V. The 0.1 C discharge capacity at the fifth cycle was recorded. Next, the negative electrode evaluation cell discharged to 2.0 V was connected to an impedance analyzer, and AC impedance measurement was performed at 2.0 V, an amplitude of 10 mV, and a frequency of 0.1 Hz to 1 MHz. When the result is plotted on the complex plane by the Cole-Cole plot method, a semicircular curve is obtained. The diameter of this arc was defined as the reaction resistance | Z | _re of the active material.

<Evaluation of room temperature rate characteristics / low temperature discharge characteristics>
Next, after being fully charged at 0.1 C at room temperature, the battery was discharged at a constant current of 0.5 C to a discharge upper limit voltage of 2.0 V, fully charged again at 0.1 C, and then at a constant current of 5 C. Discharged to 2.0V. The ratio of the discharge capacity of 5C to the 0.1C discharge capacity of the fifth cycle recorded in the test for evaluating the reaction resistance was defined as the room temperature rate characteristic (%). Here, the 0.5 C discharge capacity at room temperature was recorded. Subsequently, the battery was fully charged at room temperature and 0.1 C in the same manner, then transferred to a -20 ° C. constant temperature bath, left still for 12 hours, and discharged at a constant current of 0.5 C. The ratio of the 0.5 C discharge capacity at −20 ° C. to the 0.5 C discharge capacity at room temperature was defined as the low temperature discharge characteristic (%).

<Evaluation results>
The carbon material dispersions, carbon material dispersion varnishes, and negative electrode mixture pastes described in Examples 11-1 to 11-76 and Comparative Examples 11-1 to 11-6 are in a well dispersed state, and after 1 month There was no sedimentation or thickening. Comparative Example 11-7 using no dispersant had a high viscosity and poor fluidity from the beginning, but was used for comparison as it was. Moreover, sedimentation of the active material was confirmed after lapse of one month.

  The evaluation results of the ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of the negative electrode evaluation cells of Examples 11-1 to 11-76 and Comparative Examples 11-1 to 11-7 are shown in Tables 33-1 and 33-2. Shown in

  When the dispersion composition of the present invention was used for the negative electrode, the effect of reducing ionic resistance and reaction resistance was obtained as in the case of the positive electrode.

[Example 12-1]
<Preparation of carbon material dispersion>
In accordance with the composition shown in Table 34, water and a dispersant ca were charged into a glass bottle and mixed, and then a carbon material was added and dispersed with a paint conditioner using zirconia beads as a medium for 2 hours to obtain a carbon material dispersion.

<Preparation of carbon material dispersion varnish>
According to the composition shown in Table 34, the prepared carbon material dispersion, binder, and water were mixed with a disper to obtain a carbon material dispersion varnish.

<Preparation of mixture paste>
According to the composition shown in Table 34, the prepared carbon material dispersion varnish, the active material, and water were mixed with a disper to obtain a positive electrode mixture paste.

<Production of electrode>
<Assembly of lithium ion secondary battery positive electrode evaluation cell>
In Example 3-1, an electrode was prepared in the same manner as in Example 3-1, except that a positive electrode mixture paste containing a dispersant ca was used instead of the positive electrode mixture paste containing the dispersant a. An evaluation cell was assembled.

[Examples 12-2 to 12-35]
A positive electrode evaluation cell was assembled by dispersing in the same manner as in Example 12-1, except that the dispersants cb to di shown in Table 35 were used instead of the dispersant ca.

[Comparative Examples 12-1 to 12-4]
Using the dispersant shown in Table 36, dispersion was performed in the same manner as in Example 12-1, and a positive electrode evaluation cell was assembled. In Comparative Example 12-4, no dispersant was used, and the composition was changed to water.

<Evaluation results>
The carbon material dispersions, carbon material dispersion varnishes, and positive electrode mixture pastes prepared in Examples 12-1 to 12-35 and Comparative Examples 12-1 to 12-3 are all in a well-dispersed state. There was no sedimentation or thickening afterwards. Comparative Example 12-4 using no dispersant had a high viscosity and a large amount of coarse particles from the beginning, but was used for comparison as it was. After 1 month, it was gelled.

  Using the positive electrode evaluation cells of Examples 12-1 to 12-35 and Comparative Examples 12-1 to 12-4, ion resistance, reaction resistance, room temperature rate characteristics, low temperature discharge in the same manner as in Example 3-1. The characteristics were evaluated. The results are shown in Table 37.

  Examples 12-1 to 12-35 were excellent in all characteristics, and it was confirmed that the same effect was obtained even when water was used as the solvent.

[Examples 13-1 to 13-8] Combined use with polymer dispersant-1
A carbon material dispersion, a carbon material dispersion varnish, and a positive electrode mixture were prepared in the same manner as in Example 3-2 except that half of the dispersant b used in Example 3-2 was replaced with the polymer dispersant shown in Table 38. A paste and an electrode were prepared, and a positive electrode evaluation cell was assembled.

[Comparative Examples 13-1 to 13-8]
A carbon material dispersion, a carbon material dispersion varnish, and a positive electrode mixture were prepared in the same manner as in Comparative Example 3-1, except that half of the dispersant ba used in Comparative Example 3-1 was replaced with the polymer dispersant shown in Table 38. A paste and an electrode were prepared, and a positive electrode evaluation cell was assembled.

<Peel strength test>
Two test pieces for measuring the peel strength of the electrode were cut into two rectangles of 90 mm × 20 mm with the coating direction as the major axis. The peel strength was measured by a 180-degree peel test method using a desktop tensile tester (manufactured by Toyo Seiki Seisakusho, Strograph E3). Specifically, a 100 mm × 30 mm double-sided tape (No. 5000NS, manufactured by Nitoms Co., Ltd.) is attached on a stainless steel plate, and the produced battery electrode mixture layer is adhered to the other side of the double-sided tape, Peeling while pulling upward from below at a constant speed (50 mm / min), the average value of the stress at this time was defined as the peel strength. The results of the peel strength test were ◎: excellent, ○: no problem (good), △: peel strength lower than ○ but no problem (possible), x: weak strength, easy to peel (very bad) .

<Evaluation results>
The carbon material dispersions, carbon material dispersion varnishes, and positive electrode mixture pastes prepared in Examples 13-1 to 13-8 and Comparative Examples 13-1 to 13-8 are the same as Example 3-2 and Comparative Example 3-1. In comparison, the viscosity was slightly higher, but all were in a well dispersed state and did not settle or thicken even after one month.

  Table 39 shows the peel strength test results of the electrodes prepared in Example 3-2, Examples 13-1 to 13-8, Comparative Example 3-1, and Comparative Examples 13-1 to 13-8. Compared with Comparative Example 3-1 using only the dispersant ba, Comparative Examples 13-1 to 13-8 using various polymer dispersants all improved the peel strength. This is thought to be due to a slight improvement due to the inclusion of a polymer component capable of participating in film formation instead of the low molecular weight dispersant ba having no film forming ability. On the other hand, when Example 3-2 using only dispersant b and Examples 13-1 to 13-8 using various polymer dispersants were compared, a significant improvement was observed.

  Using the positive electrode evaluation cells of Example 3-2, Examples 13-1 to 13-8, Comparative Example 3-1, and Comparative Examples 13-1 to 13-8, the same method as in Example 3-1. Ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics were evaluated. The results are shown in Table 40.

  Examples 13-1 to 13-8 were all excellent in properties and were comparable to those of Example 3-2. By using the dispersant of the present invention and the polymer dispersant in combination, the peel strength could be greatly improved while maintaining excellent dispersibility and battery characteristics. Comparative Examples 13-1 to 13-8 were inferior to Comparative Example 3-1, and it was found that even if a polymer dispersant was used, the battery characteristics were hardly affected.

[Examples 13-9 to 13-14]
In order to confirm whether the effect of improving the peel strength can be obtained with other dispersants of the present invention, KL-506 and SM-, which were particularly effective, were referred to the peel strength test results of Examples 13-1 to 13-8. 15 was tested in the same manner. Except that half of the dispersants a, c, and d used in Examples 3-1, 3-3, and 3-4 were respectively replaced with the polymer dispersants shown in Table 41, the same as in Example 13-1. A carbon material dispersion, a carbon material dispersion varnish, a positive electrode mixture paste, and an electrode were prepared, and a positive electrode evaluation cell was assembled.

[Comparative Examples 13-9 to 13-12]
A carbon material dispersion liquid and carbon were prepared in the same manner as in Comparative Example 13-1, except that half of the dispersants bb and bc used in Comparative Examples 3-2 and 3-3 were respectively replaced with the polymer dispersants shown in Table 41. A material-dispersed varnish, a positive electrode mixture paste, and an electrode were prepared, and a positive electrode evaluation cell was assembled.

<Evaluation results>
Peel strength of electrodes prepared in Examples 3-1, 3-3, 3-4, Examples 13-9 to 13-14, Comparative Examples 3-2 and 3-3, and Comparative Examples 13-9 to 13-12 The test results are shown in Table 42. As in the case of the dispersant ba, the combination of the dispersants bb and bc and various polymer dispersants did not improve the specific peel strength, but in the case of the dispersants a, c and d, the dispersant b and Similarly, specific improvement in peel strength was confirmed by using various polymer dispersants together. Furthermore, it was confirmed that the same tendency was observed even when other dispersants of the present invention were used.

Since this effect is peculiar to the dispersant of the present invention, a polymer dispersant and a triazine ring have a structure in which —NH—R ₁ represented by the general formula (1) and two hydroxyl groups are directly connected to each other. This is thought to be due to the fact that strong intermolecular forces such as hydrogen bonds acted between the two.

  The ionic resistance, reaction resistance, room temperature rate characteristics, and low-temperature discharge characteristics of the positive electrode evaluation cells prepared in Examples 13-9 to 13-14 were the same as that of Examples 13-1 to 13-8. It was as good as that used in On the other hand, the ionic resistance, reaction resistance, room temperature rate characteristics, and low-temperature discharge characteristics of the positive electrode evaluation cells prepared in Comparative Examples 13-9 to 13-12 are the same as in Comparative Examples 13-1 to 13-8. There was almost no difference in the same degree as when there was no.

[Examples 13-15 to 13-22] Combined use with polymer dispersant-2
Except that half of the dispersant cb used in Example 3-43 was replaced with the polymer dispersant shown in Table 43, a carbon material dispersion, a carbon material dispersion varnish, a positive electrode composite were prepared in the same manner as in Example 3-43. An agent paste and an electrode were prepared, and a positive electrode evaluation cell was assembled.

[Examples 13-23 to 13-30] Combined use with polymer dispersant-3
Except that half of the dispersant cb used in Example 12-2 was replaced with the polymer dispersant shown in Table 43, a carbon material dispersion, a carbon material dispersion varnish, a positive electrode composite were prepared in the same manner as in Example 12-2. An agent paste and an electrode were prepared, and a positive electrode evaluation cell was assembled.

[Comparative Examples 13-13 to 13-20]
Except that half of the dispersant ea used in Comparative Example 3-4 was replaced with the polymer dispersant shown in Table 44, the same procedure was followed as in Comparative Example 3-4. An agent paste and an electrode were prepared, and a positive electrode evaluation cell was assembled.

[Comparative Examples 13-21 to 13-28]
Except that half of the dispersant ea used in Comparative Example 12-1 was replaced with the polymer dispersant shown in Table 44, in the same manner as Comparative Example 12-1, the carbon material dispersion, the carbon material dispersion varnish, and the positive electrode composite were respectively used. An agent paste and an electrode were prepared, and a positive electrode evaluation cell was assembled.

<Evaluation results>
Table 45 shows the peel strength test results of Examples 3-43 and 12-2, Examples 13-15 to 13-30, Comparative Example 3-4, Comparative Example 12-1, and Comparative Examples 13-13 to 13-28. Show. Regardless of amine or inorganic base, the tendency of peel strength did not change even when the solvent type was changed. Therefore, it was suggested that this specific peel strength improvement effect is a phenomenon peculiar to the triazine derivative structure of the present invention.

  Similarly, the positive electrode evaluation cells of Examples 13-15 to 13-30 also exhibited ion resistance, reaction resistance, room temperature rate characteristics, and low-temperature discharge characteristics that were as excellent as when the polymer dispersant was not used. On the other hand, the positive electrode evaluation cells of Comparative Examples 13-13 to 13-28 had the same ionic resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics as when no polymer dispersant was used. Furthermore, it was confirmed that the same tendency was observed even when other dispersants of the present invention were used.

  Next, in order to confirm whether the same peel strength improvement effect can be obtained for the negative electrode, the following test was performed.

[Examples 14-1 to 14-2]
Except that half of the dispersant b used in Example 11-2 was replaced with the polymer dispersant shown in Table 46, a carbon material dispersion, a carbon material dispersion varnish, and a negative electrode composite were obtained in the same manner as in Example 11-2. An agent paste and an electrode were prepared, and a negative electrode evaluation cell was assembled.

The ionic resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics of the negative electrode evaluation cells of Examples 14-1 and 14-2 were similar to those of Example 11-2. The peel strength test result is shown in 47. As in the case of the positive electrode, a significant improvement in peel strength was confirmed while maintaining excellent battery characteristics by using the dispersant b and the polymer dispersant in combination. Furthermore, it was confirmed that the same tendency was observed even when other dispersants of the present invention were used and when other polymer dispersants were used.

Combined use with two polymer dispersants [Example 15-1]
Subsequently, the behavior when two types of polymer dispersants were used in combination was confirmed. A carbon material dispersion, a carbon material dispersion varnish, a positive electrode mixture paste, and an electrode were prepared in the same manner as in Example 13-3, except that a further half of KL-506 used in Example 13-3 was replaced with SM-15. It produced and assembled the cell for positive electrode evaluation.

[Example 15-2]
A carbon material dispersion, a carbon material dispersion varnish, a positive electrode mixture paste, and an electrode were prepared in the same manner as in Example 13-17 except that a further half of KL-506 used in Example 13-17 was replaced with SM-15. It produced and assembled the cell for positive electrode evaluation.

[Example 15-3]
A carbon material dispersion, a carbon material dispersion varnish, a positive electrode mixture paste, and an electrode were prepared in the same manner as in Example 13-25, except that a further half of KL-506 used in Example 13-25 was replaced with SM-15. It produced and assembled the cell for positive electrode evaluation.

  Table 48 shows the peel strength test results of Examples 15-1 to 15-3. All were extremely good, and the peel strength was higher than when one kind of polymer dispersant was used. Also, the ion resistance, reaction resistance, room temperature rate characteristics, and low temperature discharge characteristics were all excellent. Furthermore, it was separately confirmed that the same tendency was observed when another dispersant of the present invention was used or when it was combined with another polymer dispersant.

From the above verification, when electrode processability and peeling during a long-term cycle become a problem, it can be compensated by combining the dispersant of the present invention and the polymer dispersant while utilizing the effects of the present invention. In addition, since a significant peel strength improvement effect can be obtained, the binder can be reduced to increase the conductive aid and active material, and it can also be designed according to the intended use of the battery, such as higher output and higher capacity. it can.

Claims (14)

A dispersant comprising a triazine derivative represented by the following general formula (1) and an amine or an inorganic base.

[In General Formula (1), R ¹ has a phenyl group having a substituent containing at least —NHC (═O) —, a benzimidazole group, an indole group which may have a substituent, or a substituent. Represents a good pyrazole group. Here, at least one of the substituents of the phenyl group having a substituent containing —NHC (═O) — is a substituent having the following structure. However, * mark represents the bonding part with the benzene ring. ]

The dispersant according to claim 1, wherein the content of the amine with respect to the triazine derivative is 0.1 to 5 molar equivalents. The dispersant according to claim 1, wherein the content of the amine with respect to the triazine derivative is 0.3 to 2 molar equivalent. The dispersant according to claim 1, wherein the content of the inorganic base relative to the triazine derivative is 0.1 to 1 molar equivalent. A dispersion composition comprising the dispersant according to claim 1, a carbon material, and a solvent. The dispersion composition according to claim 5, further comprising a polymer dispersant. The dispersion composition of claim 6, wherein the polymer dispersant has a hydroxyl group. The dispersion composition according to claim 6 or 7, wherein the polymer dispersant is a polyvinyl alcohol resin and / or a cellulose resin. The dispersion composition according to any one of claims 5 to 8, further comprising a binder. The dispersion composition for batteries which further contains an active material in the dispersion composition in any one of Claims 5-9. The dispersion composition for a battery according to claim 10, wherein the addition amount of the dispersant is 0.1 to 200 mg with respect to 1 m ^{2 of} the active material surface area. The electrode which has the mixture layer formed from the dispersion composition for batteries of Claim 10 or Claim 11 on a collector. A battery comprising the electrode according to claim 12 and a nonaqueous electrolytic solution. The battery according to claim 13, wherein the amount of the dispersant with respect to 1 ml of the non-aqueous electrolyte is 10 μg to 60 mg.