JP2010049874A - Composition for battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve performance of a battery made by using a battery composition containing conductive auxiliaries, through dispersion stabilization without jeopardizing conductivity of the conductive auxiliaries. <P>SOLUTION: A lithium secondary battery is provided with a battery composition including a dispersant containing a phthalocyanine derivative with an acid functional group, a carbon material as a conductive auxiliary agent, acid as needed, a solvent as well as a binder, and a cathode active material or an anode active material, a cathode having a cathode mixture layer on a collector, an anode having an anode mixture layer on the collector, and electrolyte containing lithium. The cathode mixture layer and the anode mixture layer are formed with the use of the above battery composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a composition used for producing an electrode constituting a battery. In particular, the electrode composition produced by the production method of the present invention is suitably used for producing a lithium secondary battery. Further, the present invention provides a lithium secondary comprising an electrode having excellent discharge characteristics or charge characteristics at a large current, cycle characteristics, and conductivity of the electrode mixture, and having low contact resistance between the electrode current collector and the electrode mixture. It relates to batteries.

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

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

  In general, lithium transition metal composite oxides such as lithium cobaltate and lithium manganate are used as the positive electrode active material, but these have low electronic conductivity and have sufficient battery performance when used alone. I can't get it. Therefore, attempts have been made to improve the conductivity and reduce the internal resistance of the electrode by adding a carbon material such as carbon black (for example, acetylene black) or graphite (graphite) as a conductive aid.

  On the other hand, graphite is usually used as the negative electrode active material. Although graphite itself has conductivity, it is known that charge and discharge characteristics are improved by adding carbon black such as acetylene black as a conductive aid together with graphite. This is because the graphite particles generally used are large, so if graphite alone is used, the gap when filled in the electrode layer will increase. However, when carbon black is used as a conductive additive, fine carbon black is used. It seems that the contact area increases by filling the gaps between the graphite particles and the resistance decreases. However, in this case as well, the conductive effect is reduced if the dispersion of the conductive aid is insufficient.

  In this way, reducing the internal resistance of the electrode is one of the very important factors in enabling discharge with a large current and improving the efficiency of charge and discharge.

  However, carbon materials with excellent electrical conductivity (conducting aids) have a strong cohesive force due to their large structure and specific surface area, making it difficult to uniformly mix and disperse in the electrode mixture forming slurry of lithium secondary batteries. is there. And, when the dispersibility and particle size control of the carbon material that is the conductive auxiliary agent are insufficient, the internal resistance of the electrode cannot be reduced because the uniform conductive network is not formed, and as a result, the lithium that is the active material There has been a problem that the performance of transition metal composite oxides and graphite cannot be sufficiently extracted. In addition, if the dispersion of the conductive additive in the electrode mixture is insufficient, resistance distribution occurs on the electrode plate due to partial aggregation, current concentrates when used as a battery, and partial heat generation occurs. In addition, problems such as accelerated deterioration may occur.

In addition, when an electrode mixture layer is formed on an electrode current collector such as a metal foil, repeated charging and discharging a large number of times causes the interface between the current collector and the electrode mixture layer, and the active material and the conductive material inside the electrode mixture. There is a problem in that the adhesion at the auxiliary agent interface is deteriorated and the battery performance is lowered. This is because the active material and the electrode mixture layer are repeatedly expanded and contracted by doping and dedoping of lithium ions during charge and discharge, so that the electrode mixture layer and the current collector interface and the active material and the conductive auxiliary agent interface are localized. This is thought to be due to the generation of shear stress and the deterioration of interfacial adhesion. In this case as well, if the dispersion of the conductive additive is insufficient, the adhesion reduction becomes significant. This is considered to be because when coarse agglomerated particles are present, the stress is hardly relaxed.
In addition, as a problem between the electrode current collector and the electrode mixture, for example, when aluminum is used as the positive electrode current collector, an insulating oxide film is formed on this surface, and the contact between the electrode current collector and the electrode mixture There is also a problem that resistance increases.

  Several proposals have been made for the problems between the electrode current collector and the electrode mixture as described above. For example, Patent Document 1 and Patent Document 2 attempt a method of forming a coating film in which a conductive agent such as carbon black is dispersed on the collector electrode as an electrode underlayer. If it is bad, sufficient effect cannot be obtained.

  In lithium secondary batteries, dispersion of a carbon material that is a conductive additive is one of the important points. Patent Documents 3 and 4 describe examples in which a surfactant is used as a dispersant when carbon black is dispersed in a solvent. However, since the surfactant has a weak adsorption force on the surface of the carbon material, it is necessary to increase the amount of the surfactant added in order to obtain good dispersion stability. As a result, the amount of the active material that can be contained Decreases and the battery capacity decreases. Further, if the surfactant is not sufficiently adsorbed on the carbon material, the carbon material will aggregate. Further, a general surfactant has a remarkably low dispersion effect in an organic solvent as compared with dispersion in an aqueous solution.

  In Patent Document 5 and Patent Document 6, when dispersing carbon black in a solvent, the dispersion state of the carbon slurry is improved by adding a dispersion resin, and the carbon slurry and the active material are mixed. A method for producing an electrode mixture is disclosed. However, although this method improves the dispersibility of carbon black, a large amount of dispersed resin is required to disperse fine carbon black having a large specific surface area, and a dispersed resin having a large molecular weight is carbon black. Since the surface is covered, the conductive network is obstructed and the resistance of the electrode is increased. As a result, the effect of improving the dispersion of carbon black may be offset.

  In addition to the improvement in the dispersibility of the electrode material, an important factor for improving the charge / discharge efficiency is an improvement in the wettability of the electrode with respect to the electrolytic solution. Since the electrode reaction occurs at the contact interface between the electrode material surface and the electrolytic solution, it is important that the electrolytic solution penetrates into the electrode and the electrode material is well wetted. As a method of promoting the electrode reaction, a method of increasing the surface area of the electrode by using a fine active material or a conductive auxiliary agent has been studied. There is a problem that it is difficult to improve battery performance because the contact area of the battery does not increase.

  As a method for improving the wettability of an electrode, Patent Document 7 discloses a method of providing fine voids between active material particles by including carbon fibers having a fiber diameter of 1 to 1000 nm in an electrode. . However, since carbon fibers are usually intertwined in a complicated manner, uniform dispersion is difficult, and a uniform electrode cannot be produced simply by mixing carbon fibers. In addition, in this document, there is a method of using carbon fiber whose surface is oxidized for dispersion control. However, when carbon fiber is directly oxidized, the conductivity and strength of carbon fiber are reduced. There is a problem of end up. Patent Document 8 discloses a method for improving the wettability by adsorbing a surfactant such as a higher fatty acid alkali salt to a negative electrode material mainly composed of carbon powder. In particular, the agent often does not have sufficient dispersion performance in a non-aqueous system, and a uniform electrode coating film cannot be obtained. In these examples, the total performance including the dispersibility of the electrode material was insufficient.

  In addition to the above-described problems, the lithium secondary battery also has problems related to safety such as battery performance deterioration due to reduction / precipitation of metal components on the negative electrode, and excessive heat generation and ignition due to occurrence of a short circuit. Causes of performance degradation and short-circuiting due to metal components include (1) metal impurities such as copper and iron in the manufacturing process, and (2) metal ions contained in the positive electrode, current collector, battery container, etc. in the electrolyte. It is conceivable that, after elution, the metal ions are reduced and deposited on the negative electrode, and (3) metal ions are eluted from the positive electrode active material due to the deterioration of the positive electrode, and are reduced and deposited on the negative electrode.

  In order to suppress the precipitation of metal ions, Patent Document 9 suppresses the precipitation at the negative electrode by trapping the cation eluted from the positive electrode on the separator surface by introducing a cation exchange group on the surface of the separator. Attempts have been made. However, in this case, to obtain a separator in which a cation exchange group is introduced on the surface by immersing a nonwoven fabric as a separator substrate in an aqueous solution of acrylic acid (monomer) and a polymerization initiator and irradiating ultraviolet rays in a nitrogen atmosphere. The manufacturing process becomes complicated and is not suitable for mass production. In this case, ions that have passed through the separator cannot be captured.

In view of the problems as described above, the present invention provides a battery composition containing a conductive auxiliary agent, which achieves dispersion stabilization without inhibiting the conductivity of the conductive auxiliary agent, and electrolysis of the conductive auxiliary agent that is a carbon material. It aims at improving the battery performance of the battery produced using this by improving the wettability with respect to a liquid, and providing the function which capture | acquires a metal ion to a conductive support agent.
JP 2000-123823 A Japanese Patent Laid-Open No. 2002-298753 JP-A-63-236258 JP-A-8-190912 Japanese Patent Laid-Open No. 2003-157846 JP-T-2006-51679 gazette Japanese Patent Laying-Open No. 2005-063955 JP-A-6-60877 JP 2002-25527 A

  As a result of intensive studies to achieve the above object, the present inventors have added a phthalocyanine derivative having an acidic functional group as a dispersant when dispersing the carbon material as a conductive additive in a solvent. In addition to being able to prepare a dispersion of carbon material particles having excellent dispersion stability, the composition containing the dispersion of carbon material particles further reduces the resistance of the electrode and the electrode current collector and electrode mixture, or The present inventors have found an effect of improving battery performance that seems to be caused by an improvement in adhesion between the active material and the conductive additive. In addition, the present inventors have found an effect of improving wettability with respect to an electrolytic solution and an effect of suppressing precipitation of metal ions, and have made the present invention.

  The battery composition of the present invention can be used for lithium secondary batteries, nickel hydride secondary batteries, nickel cadmium secondary batteries, alkaline manganese batteries, lead batteries, fuel cells, capacitors, etc., and in particular lithium secondary batteries. It is suitable for use in.

That is, the present invention relates to a battery composition comprising a phthalocyanine derivative as a dispersant having an average number of substituents of acidic functional groups of 0.4 to 2.9, and a carbon material as a conductive additive. .
Further, the present invention is acidic functional group is a sulfonic acid group _(-SO 3 H), relating to the composition for a battery is a carboxyl group (-COOH).
Moreover, this invention relates to said battery composition whose acidic functional group is sulfonic acid ammonium salt and carboxylic acid ammonium salt.
Moreover, this invention relates to said battery composition whose acidic functional group is a sulfonic acid metal salt or a carboxylic acid metal salt.
Moreover, this invention relates to said battery composition characterized by including a solvent.
In addition, the present invention relates to the above battery composition, wherein the dispersed particle diameter (D ₅₀ ) of the carbon material as a conductive additive is 2 μm or less.

Moreover, this invention relates to said battery composition characterized by including a binder component.
The present invention also relates to the above battery composition, wherein the binder component is a polymer compound containing a fluorine atom in the molecule.
The present invention also relates to the above battery composition, wherein the solvent is N-methylpyrrolidone.
Moreover, this invention relates to said battery composition characterized by including a positive electrode active material or a negative electrode active material.
Further, the present invention is a lithium secondary battery comprising 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 an electrolyte containing lithium, The present invention relates to a lithium secondary battery, wherein the positive electrode mixture layer or the negative electrode mixture layer is formed using the battery composition.

  According to a preferred embodiment of the present invention, in the battery composition, the dispersion stability of the conductive assistant is excellent, and the dispersion stability is achieved without hindering the conductivity of the conductive assistant, and In the electrode of the present battery composition, the wettability with respect to the electrolytic solution is improved and the precipitation of metal ions is suppressed. Therefore, by using the battery composition according to a preferred embodiment of the present invention, for example, lithium Battery performance of secondary batteries and the like can be improved comprehensively.

  The battery composition according to the present invention is characterized by containing a dispersant containing a phthalocyanine derivative having an acidic functional group and a carbon material as a conductive additive. The details thereof will be described below.

<Conductive auxiliary agent (carbon material)>
As the conductive aid in the present invention, a carbon material is most preferable. The carbon material is not particularly limited as long as it is a conductive carbon material, but graphite, carbon black, carbon nanotube, carbon nanofiber, carbon fiber, fullerene, etc. alone or in combination of two or more. Can be used. From the viewpoint of conductivity, availability, and cost, it is preferable to use carbon black.

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

  The oxidation treatment of carbon is performed by treating carbon at a high temperature in the air or by secondary treatment with nitric acid, nitrogen dioxide, ozone, etc., for example, such as phenol group, quinone group, carboxyl group, carbonyl group. This is a treatment for directly introducing (covalently bonding) an oxygen-containing polar functional group to the carbon surface, and is generally performed to improve the dispersibility of carbon. However, since it is common for the conductivity of carbon to fall, so that the introduction amount of a functional group increases, it is preferable to use the carbon which has not been oxidized.

As the specific surface area of the carbon black used increases, the number of contact points between the carbon black particles increases, which is advantageous in reducing the internal resistance of the electrode. Specifically, the specific surface area (BET) determined from the adsorption amount of nitrogen is 20 m ² / g or more and 1500 m ² / g or less, preferably 50 m ² / g or more and 1500 m ² / g or less, more preferably 100 m ^2. / G or more and 1500 m ² / g or less are desirable. When carbon black having a specific surface area of less than 20 m ² / g is used, it may be difficult to obtain sufficient conductivity, and carbon black of more than 1500 m ² / g may be difficult to obtain from commercially available materials. is there.

  Further, the particle size of carbon black to be used is preferably 0.005 to 1 [mu] m, and particularly preferably 0.01 to 0.2 [mu] m in terms of primary particle size. However, the primary particle diameter here is an average of the particle diameters measured with an electron microscope or the like.

  Examples of commercially available carbon black include Toka Black # 4300, # 4400, # 4500, # 5500 (Tokai Carbon Co., Furnace Black), Printex L and the like (Degussa Co., Furnace Black), Raven 7000, 5750, 5250, 5000 ULTRA III, 5000 ULTRA, etc., Conductex SC ULTRA, Conductex 975 ULTRA, etc. (Columbian Co., Furnace Black), # 2350, # 2400B, # 30050B, # 3030B, # 3230B, # 3350B, # 3400B, # 5400B, etc. (Manufactured by Chemical Co., Furnace Black), MONARCH1400, 1300, 900, Vulcan XC-72R, Black Pearls 2000, etc. Fans Black), Ensaco 250G, Ensaco 260G, Ensaco 350G, SuperP-Li (manufactured by TIMCAL), Ketjen Black EC-300J, EC-600JD (manufactured by Akzo), Denka Black, Denka Black HS-100, FX-35 (Electrochemical Industry) However, it is not limited to these.

<Dispersant>
The dispersant in the present invention is characterized by containing a phthalocyanine derivative having an acidic functional group. In particular, it is preferable to include one or more compounds selected from phthalocyanine derivatives represented by the following general formula (1).

  General formula (1)

式中のＭはＣｕ、Ｔｉ、Ａｌ、Ｆｅ、Ｃｏ、Ｎｉ、Ｚｎ、Ｐｔ、Ｖまたは、ＨＨを表すが、中でもＨＨが好ましい。
Ｘ^１、Ｘ^２、Ｘ^３、Ｘ^４は独立にＢｒ、Ｃｌを表し、
Ｙ^１、Ｙ^２、Ｙ^３、Ｙ^４は独立に酸性官能基−ＳＯ_３Ｚまたは−ＣＯＯＺを表し、
Ｚは１〜３価のカチオンの一当量を表し、
ｋ^１、ｋ^２、ｋ^３、ｋ^４、ｎ^１、ｎ^２、ｎ^３、ｎ^４は、いずれも０〜４の整数を表し、
ｎ^１＋ｎ^２＋ｎ^３＋ｎ^４＝１〜４が好ましく、
また、ｋ^１＋ｋ^２＋ｋ^３＋ｋ^４＝０〜３が好ましい。

M in the formula represents Cu, Ti, Al, Fe, Co, Ni, Zn, Pt, V, or HH. Among them, HH is preferable.
X ¹ , X ² , X ³ , X ⁴ independently represent Br, Cl;
Y ¹ , Y ² , Y ³ , Y ⁴ independently represent an acidic functional group —SO ₃ Z or —COOZ;
Z represents one equivalent of a 1 to 3 valent cation,
k ¹ , k ² , k ³ , k ⁴ , n ¹ , n ² , n ³ , n ⁴ all represent an integer of 0 to 4;
n ¹ + n ² + n ³ + n ⁴ = 1 to 4 is preferable,
^{Also, k 1 + k 2 + k} 3 + k 4 = 0~3 is preferable.

  Z in the formula of the general formula (1) represents one equivalent of a monovalent to trivalent cation, for example, a hydrogen atom (proton), a metal cation, or a quaternary ammonium cation. Examples of the metal include lithium, sodium, potassium, calcium, barium, magnesium, aluminum, nickel, and cobalt.

The quaternary ammonium cation is a single compound having a structure represented by the general formula (2) or a mixture.
General formula (2)

Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４は、水素、置換基を有してもよいアルキル基、置換基を有してもよいアルケニル基、または置換基を有してもよいアリール基のいずれかを表す。

R ¹ , R ² , R ³ and R ⁴ are any of hydrogen, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an aryl group which may have a substituent. Represents

R ¹ , R ² , R ³ and R ⁴ in the general formula (2) may be the same or different. ^Also, if the ^{R 1, R 2, R 3} , R 4 has a carbon atom, the carbon number 1 to 40, preferably 1 to 30, more preferably 1 to 20. If the carbon number exceeds 40, the conductivity of the electrode may be reduced. )
Specific examples of quaternary ammonium include dimethylammonium, trimethylammonium, diethylammonium, triethylammonium, hydroxyethylammonium, dihydroxyethylammonium, 2-ethylhexylammonium, dimethylaminopropylammonium, laurylammonium, stearylammonium, and the like. It is not limited to these.

The method for synthesizing the dispersant is not particularly limited, but it is general that the dispersant is sulfonated by using a sulfonating agent such as fuming sulfuric acid, concentrated sulfuric acid, and chlorosulfonic acid. Moreover, when introducing a carboxyl group, the method of using what has a carboxyl group as a raw material at the time of phthalocyanine synthesis | combination etc. are mentioned. In any method, the number of acidic functional groups of the synthesized phthalocyanine derivative has a distribution. For example, how many sulfonic acid groups are introduced into phthalocyanine is determined by conditions such as reaction temperature and reaction time, but since there are multiple places where phthalocyanine can introduce functional groups, what kind of reaction conditions should be adopted. However, the obtained phthalocyanine compound having an acidic functional group is not one kind, but a mixture of several phthalocyanine compounds having different numbers of acidic functional groups (for example, unsubstituted, monosubstituted, disubstituted, trisubstituted or more Mixture).
Therefore, unless it is separated and purified, it does not become a single compound, and the number of acidic functional groups of the phthalocyanine derivative is expressed as an average value per molecule of phthalocyanine.
The average number of substituents of the acidic functional group of the phthalocyanine derivative that can be preferably used is 0.4 to 2.9, and more preferably 0.5 to 2.9.

  The above-described dispersant is considered to exhibit a dispersing effect when the added dispersant acts (for example, adsorbs) on the surface of the carbon material. It is considered that the action of these dispersants on the carbon material proceeds by completely or partially dissolving the phthalocyanine derivative having an acidic functional group in the solvent and adding and mixing the carbon material in the solution. And, it is considered that the electrical functional group (repulsive action) is induced by polarization or dissociation of the acidic functional group of the dispersant acting on the surface of the carbon material, and the carbon material is deaggregated. Therefore, in the present invention, (1) a functional group is not directly introduced (covalently bonded) to the carbon material surface, and (2) a good dispersion can be obtained without using a dispersion resin. From these, good dispersion can be obtained without deteriorating the conductivity of the carbon material. Then, by using the battery composition of the present invention in which the carbon material is well dispersed, an electrode in which the carbon material is uniformly dispersed can be produced.

  Further, in the electrode using the battery composition of the present invention, since the dispersant having a polar functional group is present on the surface of the carbon material, the wettability of the carbon material with respect to the electrolytic solution is improved, and the above-described uniform dispersion effect is achieved. This improves the wettability of the electrode with respect to the electrolyte.

Each of the dispersants of the present invention has a good dispersion effect and wettability improvement effect, but in particular, when Z in the formula of the general formula (1) is a quaternary ammonium cation, the wettability of the carbon material to the electrolyte solution This is preferable because the improvement effect is particularly great.
Moreover, when Z is a proton, it is preferable because the metal ion in the electrolytic solution is captured by the acidic functional group, and the effect of suppressing a decrease in battery performance and short circuit due to metal deposition is great.

  Furthermore, when these phthalocyanine derivatives having an acidic functional group are used in the case of using a fluororesin binder such as polyvinylidene fluoride, which will be described later, due to the effect of the acidic functional group (for example, acidification effect, buffer effect, etc.) It is also possible to suppress the denaturation due to the dehydrofluorination reaction and suppress the increase in the viscosity (or gelation) of the paint and the decrease in the adhesion of the electrode film due to the curing of the binder.

<Solvent>
Examples of the solvent used in the present invention include alcohols, glycols, cellosolves, amino alcohols, amines, ketones, carboxylic acid amides, phosphoric acid amides, sulfoxides, carboxylic acid esters, and phosphoric acid. Examples include esters, ethers, nitriles, water and the like.
Among these, it is preferable to use a polar solvent having a relative dielectric constant of 15 or more. The relative dielectric constant is one of the indices indicating the strength of the solvent polarity, and is described in Asahara et al., “Solvent Handbook” (Kodansha Scientific Co., Ltd., 1990).

  For example, methyl alcohol (dielectric constant: 33.1), ethyl alcohol (23.8), 2-propanol (18.3), 1-butanol (17.1), 1,2-ethanediol (38.66) ), 1,2-propanediol (32.0), 1,3-propanediol (35.0), 1,4-butanediol (31.1), diethylene glycol (31.69), 2-methoxyethanol ( 16.93), 2-ethoxyethanol (29.6), 2-aminoethanol (37.7), acetone (20.7), methyl ethyl ketone (18.51), formamide (111.0), N-methylformamide (182.4), N, N-dimethylformamide (36.71), N-methylacetamide (191.3), N, N-dimethylacetamide (3 .78), N-methylpropionamide (172.2), N-methylpyrrolidone (32.0), hexamethylphosphoric triamide (29.6), dimethyl sulfoxide (48.9), sulfolane (43.3), acetonitrile (37.5), propionitrile (29.7), water (80.1), and the like, but are not limited thereto.

In particular, the use of a polar solvent having a relative dielectric constant of 15 or more and 200 or less, preferably 15 or more and 100 or less, and more preferably 20 or more and 100 or less can provide good dispersion stability of the carbon material. preferable.
Solvents with a relative dielectric constant of less than 15 often have a significant decrease in the solubility of the dispersant, and good dispersion cannot be obtained. Is often not obtained.

  In addition, the dispersion stability of the carbon material tended to be influenced by the electron donating property of the solvent. It is preferable to use a solvent having a large electron donating effect. Particularly, a solvent having a donor number of 15 Kcal / mol or more is preferable, but a solvent having 20 Kcal / mol or more and 60 Kcal / mol or less is more preferable.

The number of donors is a scale that measures the strength of electron donating properties of various solvents. As a standard acceptor, 10 ⁻³ M SbCl ₅ in dichloroethane is selected, and is a value defined as a reaction molar enthalpy value with a donor. The larger the value, the stronger the electron donating property of the solvent. Also, for some solvents, the donor number is estimated indirectly from the ²³ Na-NMR chemical shift of NaClO _{4 in} the solvent. Regarding the number of donors, V.V. Gutman (translated by Otsuki, Okada), “Donor and Acceptor” (Japan Society of Science Publishing Center, 1983). Although depending on the dielectric constant of the solvent, if a solvent having a donor number lower than 15 Kcal / mol is used, a sufficient dispersion stabilization effect may not be obtained. Moreover, it seems that there is no remarkable dispersion | distribution improvement effect even if it uses the solvent in which the donor number exceeded 60 Kcal / mol.

  As a solvent having a donor number of 15 Kcal / mol or more, for example, methyl alcohol (donor number: 19), ethyl alcohol (20), ethylamine (55), t-butylamine (57), ethylenediamine (55), pyridine (33. 1), acetone (17), formamide (24), N, N-dimethylformamide (26.6), N, N-diethylformamide (30.9), N, N-dimethylacetamide (27.8), N , N-diethylacetamide (32.2), N-methylpyrrolidone (27.3), hexamethylphosphoric triamide (38.8), dimethyl sulfoxide (29.8), ethyl acetate (17.1) trimethyl phosphate (23 ), Tributyl phosphate (23.7), tetrahydrofuran (20.0), isobutyronitrile (15 4), isopropylidene Ono nitrile (16.1), water (18.0) and the like, without limitation.

  It seems that the use of a solvent having a large effect of promoting the polarization or dissociation of the acidic functional group of the dispersant is important for obtaining good dispersion stability of the carbon material. A solvent having a large electron donating property has a strong solvating power with respect to a phthalocyanine derivative having an acidic functional group, so that it polarizes the acidic functional group of the dispersant and promotes the dissociation of the polarized acidic functional group by the solvent having a large relative dielectric constant. It seems to be. Therefore, in order to obtain good dispersion stability of the carbon material, a solvent having a large relative dielectric constant and a solvent having a large donor number are used in combination, or a solvent having a large relative dielectric constant and a large number of donors is used. It is preferable.

  The solvent used is preferably an aprotic polar solvent. An aprotic polar solvent is a polar solvent that does not have the ability to release protons and does not self-dissociate. Aprotic polar solvents do not cause self-association due to hydrogen bonding, and the solvent itself aggregates. The nature is weak. Therefore, the penetration of carbon materials into aggregates is strong, and a dispersion promoting effect is expected. In addition, since the aprotic polar solvent is weak in cohesiveness of the solvent itself, it has a strong dissolving power and can dissolve various dispersants and resins, so that it has excellent versatility. Furthermore, when considering dissolving a phthalocyanine derivative having an acidic functional group in a solvent, an aprotic polar solvent solvates only the cationic species, and therefore solvates only the proton or counter cation in the acidic functional group. It will be. At this time, since the anion side including the phthalocyanine derivative skeleton remains bare without being solvated, an effect such as that the action (for example, adsorption) of the phthalocyanine derivative skeleton portion on the carbon material surface is difficult to be inhibited is expected. .

In addition, the selection of the solvent in the present invention is performed when a phthalocyanine derivative having an acidic functional group as a dispersant, a carbon material as a conductive auxiliary, and an electrode active material or a binder component described later in addition to the solvent are added. In addition to the influence of the solvent on the dispersibility, the reactivity with the active material and the solubility in the binder component are taken into consideration. It is preferable to select a solvent having high dispersibility, low reactivity with the active material, and high solubility of the binder component.
Furthermore, from the viewpoint of reducing environmental burdens and economic advantages, when recovering and reusing the solvent discharged in the electrode manufacturing process, it is preferable to use a single solvent instead of a mixed solvent.

  As described above, as a solvent satisfying the effect of promoting the dispersion stability of the carbon material, the reactivity with the active material, and the solubility of the binder component and having versatility in a single use, an amide solvent is preferable. Preference is given to the use of amide aprotic solvents such as N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide.

<Positive electrode active material and negative electrode active material>
When the composition of the present invention is used for a positive electrode mixture or a negative electrode mixture, at least a positive electrode active material or a negative electrode active material is contained in addition to the dispersant, the carbon material as a conductive additive, and a solvent.

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

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, silicon alloy negative _{electrode, Li X Fe 2 O 3,} Li X Fe 3 O 4 Metal oxides such as Li _X WO ₂ , conductive polymers such as polyacetylene and poly-p-phenylene, amorphous carbonaceous materials such as soft carbon and hard carbon, artificial graphite such as highly graphitized carbon materials, Alternatively, carbonaceous powders such as natural graphite, carbon black, mesophase carbon black, resin-fired carbon materials, gas-grown carbon fibers, carbon fibers, and the like are used.

<Binder>
The composition of the present invention preferably further contains a binder component. As binders to be used, ethylene, propylene, vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic ester, methacrylic acid, methacrylic ester, acrylonitrile, styrene, vinyl butyral, vinyl acetal, vinyl pyrrolidone, etc. Polymer or copolymer containing as a structural unit: polyurethane resin, polyester resin, phenol resin, epoxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, acrylic resin, formaldehyde resin, silicone resin, fluorine resin; carboxymethylcellulose Such cellulose resins; rubbers such as styrene-butadiene rubber and fluororubber; and conductive resins such as polyaniline and polyacetylene. Moreover, the modified body and mixture of these resin, and a copolymer may be sufficient. In particular, 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.

  Moreover, as for the weight average molecular weight of these resin as a binder, 10,000-1,000,000 are preferable. When the molecular weight is small, the resistance of the binder may decrease. When the molecular weight is increased, the resistance of the binder is improved, but the viscosity of the binder itself is increased and the workability is lowered.

<Use of composition of the present invention>
The composition of the present invention can be used for a positive electrode mixture or a negative electrode mixture. When used for a positive electrode mixture or a negative electrode mixture, a positive / active material in which a positive electrode active material or a negative electrode active material, preferably further a binder component, is added to the composition containing the dispersant, the carbon material as a conductive additive, and a solvent. It is preferable to use it as a negative electrode mixture paste.

  The ratio of the active material to the total solid content in the electrode mixture paste is preferably 80% by weight or more and 98.5% by weight or less. Moreover, the ratio of the solid content which combined the dispersing agent containing the phthalocyanine derivative which has an acidic functional group with respect to the total solid content in an electrode compound-material paste, and the carbon material as a conductive support agent is 0.5 weight% or more. 19% by weight or less is preferable. The proportion of the binder component in the total solid content in the electrode mixture paste is preferably 1% by weight or more and 10% by weight or less. The proper viscosity of the electrode mixture paste depends on the method of applying the electrode mixture paste, but generally it is preferably 100 mPa · s or more and 30,000 mPa · s or less.

  The positive / negative electrode composite paste not only has excellent dispersibility of the carbon material particles as a conductive additive, but also has an effect of relaxing aggregation of the positive / negative electrode active material. Because the carbon material particles, which are conductive assistants, have excellent dispersibility, the energy of mixing and dispersing the carbon material as the conductive assistant and the positive and negative electrode active materials in the solvent is the aggregate of the carbon material (conductive assistant). It is believed that the active material can be efficiently transferred to the active material without being obstructed, and as a result, the dispersibility of the positive and negative electrode active materials can be improved.

  In the positive electrode mixture paste, the carbon material particles as the conductive auxiliary agent can be uniformly coordinated and adhered around the positive electrode active material, and excellent conductivity and adhesion can be imparted to the positive electrode mixture layer. Further, since the conductivity is improved, the amount of the carbon material added as a conductive auxiliary agent can be reduced, so that the amount of the positive electrode active material added can be relatively increased, and the capacity which is a large characteristic of the battery can be increased. Can be bigger.

  Furthermore, since the positive electrode mixture paste of the present invention has very little aggregation of the positive electrode active material and the carbon material (conducting aid), a uniform coating film having high smoothness can be obtained when applied to a current collector. The adhesion between the current collector and the positive electrode mixture is improved. Moreover, since the dispersing agent having an acidic functional group acts (for example, adsorbs) on the surface of the carbon material (conducting aid), the surface of the positive electrode active material such as a lithium transition metal composite oxide and the carbon material (conducting aid) ) The interaction with the surface is strengthened, and the adhesion between the positive electrode active material and the carbon material (conducting aid) is improved as compared with the case where a dispersant having an acidic functional group is not used.

  In the negative electrode composite paste, when a carbon material-based active material is used as the negative electrode active material, the aggregation of the carbon material-based active material is mitigated by the effect of the phthalocyanine derivative having an acidic functional group added as a dispersant. Is done. The carbon material particles (conducting aid) can be uniformly coordinated and adhered around the negative electrode active material, and excellent conductivity, adhesion and wettability can be imparted to the negative electrode mixture layer.

  The composition of the present invention can also be used for an electrode underlayer. When used for an electrode underlayer, a dispersion composed of a phthalocyanine derivative having an acidic functional group, a carbon material as a conductive additive and a solvent may be used as it is. It is preferable to use as. The ratio of the carbon material as a conductive additive to the total solid content of the composition used for the electrode underlayer is preferably 5% by weight or more and 95% by weight or less, more preferably 10% by weight or more and 90% by weight or less. If the carbon material as the conductive auxiliary agent is small, the conductivity of the underlayer may not be maintained. On the other hand, if the carbon material as the conductive auxiliary agent is excessive, the resistance of the coating film may be reduced. In addition, the appropriate viscosity of the electrode base paste depends on the method of applying the electrode base paste, but generally it is preferably 100 mPa · s or more and 30,000 mPa · s or less.

<The manufacturing method of the composition of this invention>
Next, the manufacturing method of the composition of this invention is demonstrated.
In the composition of the present invention, for example, in the presence of a dispersant containing a phthalocyanine derivative having an acidic functional group, a carbon material as a conductive auxiliary agent is dispersed in a solvent, and the positive electrode active material, if necessary, It can manufacture by mixing a negative electrode active material or a binder component. The order of addition of each component is not limited to this. Moreover, you may add a solvent further as needed.

  The above manufacturing method is such that a dispersant containing a phthalocyanine derivative having an acidic functional group is completely or partially dissolved in a solvent, and a carbon material as a conductive aid is added to and mixed with the dispersant. Is dispersed in the solvent while acting (for example, adsorbing) on the carbon material. The concentration of the carbon material in the dispersion at this time is preferably 1% by weight or more and 50% by weight or less, although it depends on the characteristic values of the carbon material such as the specific surface area and surface functional group amount of the carbon material used. More preferably, it is 5% by weight or more and 35% by weight or less. If the concentration of the carbon material is too low, the production efficiency is deteriorated. If the concentration of the carbon material is too high, the viscosity of the dispersion is remarkably increased, and the dispersion efficiency, the efficiency of the contamination removal process described later, and the handling of the dispersion are improved. May decrease. In particular, when a step for removing contamination is added, the viscosity of the dispersion at this time is preferably 10,000 mPa · s or less, more preferably 5,000 mPa · s or less, and still more preferably 3,000 mPa · s or less.

  The amount of the dispersant containing the phthalocyanine derivative having an acidic functional group is determined by the specific surface area of the carbon material as the conductive auxiliary agent used. Generally, the dispersant is 0.5 to 40 parts by weight, preferably 1 to 35 parts by weight, more preferably 2 to 30 parts by weight with respect to 100 parts by weight of the carbon material. Or less. When the amount of the dispersing agent is small, a sufficient dispersing effect cannot be obtained, and an effect of improving wettability to the electrolytic solution and an effect of suppressing metal deposition cannot be obtained sufficiently. Moreover, even if it adds excessively, the remarkable dispersion | distribution improvement effect is not acquired.

  The dispersed particle size of the carbon material as the conductive assistant may be reduced to 0.03 μm or more and 2 μm or less, preferably 0.05 μm or more and 1 μm or less, more preferably 0.05 μm or more and 0.5 μm or less. desirable. It may be difficult to produce a composition having a dispersed particle size of the carbon material as the conductive aid of less than 0.03 μm. In addition, when a composition in which the dispersed particle diameter of the carbon material as the conductive auxiliary agent exceeds 2 μm is used, the additive amount of the conductive auxiliary agent must be increased in order to reduce the resistance distribution of the electrode and reduce the resistance. There may be a problem such as disappearing. The dispersed particle size referred to here is a particle size (D50) that is 50% when the volume ratio of the particles is integrated from the fine particle size distribution in the volume particle size distribution. A particle size distribution meter such as a dynamic light scattering type particle size distribution meter ("Microtrack UPA" manufactured by Nikkiso Co., Ltd.).

  Further, as a device for dispersing the carbon material in the solvent while causing the dispersant to act on the carbon material (for example, adsorption), a disperser usually used for pigment dispersion or the like can be used. For example, mixers such as dispersers, homomixers, planetary mixers, homogenizers ("Clearmix" manufactured by M Technique, PRIMIX "Fillmix", etc.), paint conditioners (manufactured by Red Devil), ball mills, sand mills ( Media type dispersers such as “Dynomill” manufactured by Shinmaru Enterprises, Inc.), Attritor, Pearl Mill (“DCP Mill” manufactured by Eirich), Coball Mill, etc., Wet Jet Mill (“Genus PY” manufactured by Genus, Sugino Machine Co., Ltd.) Media-less dispersers such as “Starburst” manufactured by Nanomizer, “Nanomizer” manufactured by Nanomizer, etc., “Claire SS-5” manufactured by M Technique, and “MICROS” manufactured by Nara Machinery Co., other roll mills, etc. It is not limited to. 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 disperser in which the agitator and vessel are made of a ceramic or resin disperser, or the metal agitator and vessel surface are treated with tungsten carbide spraying or resin coating. Is preferably used. And as a media, it is preferable to use ceramic beads, such as glass beads, zirconia beads, and alumina beads, and among them, the use of zirconia beads is preferable. Moreover, also when using a roll mill, it is preferable to use a ceramic roll. Only one type of dispersion device may be used, or a plurality of types of devices may be used in combination.

  In addition, it is preferable to include a step of removing contaminants such as metal foreign matters when dispersing the carbon material. Carbon materials such as carbon black, graphite, and carbon fiber often contain metallic foreign substances derived from their manufacturing processes (as line contamination and catalysts), and removing these foreign substances is a short circuit of the battery. Is very important to prevent. In the present invention, due to the effect of the dispersant containing a phthalocyanine derivative having an acidic functional group, the aggregation of the carbon material is well loosened, and the viscosity of the dispersion becomes low. Therefore, compared to the case where the dispersant is not added, Even when the carbon material concentration in the dispersion is high, foreign matters can be efficiently removed. Examples of methods for removing foreign substances include iron removal with a magnet, filtration, and centrifugation.

  Examples of the method for adding the binder component include a method in which a solid binder component is added and dissolved while stirring a dispersion obtained by dispersing a carbon material as a conductive additive in a solvent in the presence of the dispersant. . Moreover, what melt | dissolved the binder component in the solvent previously is produced, and the method of mixing with the said dispersion is mentioned. Further, after the binder component is added to the dispersion, the dispersion treatment may be performed again with the dispersion apparatus.

  In addition, when a carbon material as a conductive additive is dispersed in a solvent in the presence of a dispersant containing a phthalocyanine derivative having an acidic functional group, a part or all of the binder component is simultaneously added to perform a dispersion treatment. You can also.

  As a method for adding the positive electrode active material or the negative electrode active material, the positive electrode active material or the negative electrode active material is added while stirring the dispersion obtained by dispersing the carbon material as the conductive additive in the solvent in the presence of the above-described dispersant. And a dispersion method. Further, in the presence of a dispersant containing a phthalocyanine derivative having an acidic functional group, when a carbon material as a conductive additive is dispersed in a solvent, a part or all of the positive electrode active material or the negative electrode active material may be added simultaneously. Distributed processing can also be performed. Moreover, as an apparatus for performing mixing and dispersion at this time, the above-described dispersers used for ordinary pigment dispersion and the like can be used.

  As described above, the battery composition of the present invention is usually produced, distributed, and used as a dispersion (liquid) containing a solvent, a paste, and the like. This is because even if the conductive auxiliary agent or active material and the dispersing agent are mixed in a dry powder state, the dispersing agent cannot be uniformly applied to the conductive auxiliary agent or the active material. This is because, by dispersing the conductive additive and the active material in the solvent in the presence of, the dispersant can be made to act uniformly on the conductive additive and the active material. Further, as described below, when the electrode mixture layer is formed on the current collector, it is preferable to apply the liquid dispersion as uniformly as possible and dry it.

  However, for example, a dispersion prepared by a liquid phase method may be considered as a dry powder by once removing the solvent for reasons such as transportation cost. And it is also considered that this dry powder is redispersed with an appropriate solvent and used for forming an electrode mixture layer. Therefore, the composition of the present invention is not limited to a liquid dispersion, and may be a composition in a dry powder state.

  In the production method of the present invention, instead of dissolving or completely dissolving a dispersant in a solvent and adding and mixing a carbon material as a conductive aid in the solution, the above-described dispersant is treated in advance. A carbon material as an auxiliary agent may be dispersed in a solvent.

  Examples of the method for obtaining a carbon material as a conductive additive treated with a dispersant containing a phthalocyanine derivative having an acidic functional group include a dry treatment method and a treatment method in a liquid phase.

  Examples of the dry treatment include a method of causing the dispersant to act (for example, adsorb) on the surface of the carbon material while mixing, pulverizing, and the like of the carbon material and the dispersant with a dry treatment apparatus at room temperature or under heating. . The equipment to be used is not particularly limited. Media type dispersers such as paint conditioner (manufactured by Red Devil), ball mill, attritor, vibration mill, kneader, roller mill, stone mill, planetary mixer, fen Medialess dispersion / kneading machines such as Shell Mixer, Hybridizer (Nara Machinery Co., Ltd.), Mechano Micros (Nara Machinery Co., Ltd.), Mechano Fusion System AMS (Hosokawa Micron Co., Ltd.) can be used. In consideration of metal contamination and the like, it is preferable to use a medialess dispersion / kneading machine.

  Liquid phase treatment includes mixing a dispersing agent and a carbon material as a conductive additive in an organic solvent or water, and allowing the dispersing agent to act on the carbon material (for example, adsorption), and a carbon material on which the dispersing agent has acted. It is preferable to include a step of agglomerating to obtain aggregated particles.

  For example, for the treatment in an organic solvent system, the step of causing the dispersant to act on the carbon material (for example, adsorption) includes a dispersant containing a phthalocyanine derivative having an acidic functional group, a carbon material as a conductive additive, and an organic solvent. And the dispersing agent is allowed to act (for example, adsorb) on the carbon material. In particular, a dispersant containing a phthalocyanine derivative having an acidic functional group is completely or partially dissolved in an organic solvent, and a carbon material as a conductive assistant is added to the solution to mix and disperse the dispersant. Is preferably caused to act (for example, adsorb) on the carbon material.

As the solvent used in the step of causing the dispersing agent to act on the carbon material (for example, adsorption), it is preferable to use a polar solvent having a relative dielectric constant of 15 or more. In particular, in order to increase the concentration of the carbon material in the treatment liquid and increase the treatment efficiency, the relative dielectric constant is 15 or more and 200 or less, preferably 15 or more and 100 or less, more preferably 20 or more and 100 or less. It is preferred to use a polar solvent.
Solvents with a relative dielectric constant of less than 15 significantly reduce the solubility of the dispersant and the dispersibility of the carbon material, so the carbon material concentration often cannot be increased, and the relative dielectric constant exceeds 200. Even when a solvent is used, a remarkable effect is often not obtained.

  In addition, the dispersion stability of the carbon material tends to be influenced by the electron donating property of the solvent, and it is preferable to use a solvent having a large electron donating effect, and in particular, a solvent having a donor number of 15 Kcal / mol or more is preferable. However, the solvent of 20 Kcal / mol or more and 60 Kcal / mol or less is still more preferable. These organic solvents may be used alone or in combination of two or more. It is preferable to use a combination of a solvent having a large relative dielectric constant and a solvent having a large donor number, or a solvent having a large relative dielectric constant and a large number of donors.

  Further, as a device for causing the dispersing agent to act on the carbon material (for example, adsorption) while mixing and dispersing the carbon material in a solvent, a disperser usually used for pigment dispersion or the like can be used. For example, mixers such as kneaders, dispersers, homomixers, planetary mixers, homogenizers (“Clearmix” manufactured by M Technique, PRIMIX “Fillmix”, etc.), paint conditioners (manufactured by Red Devil), ball mill, Media type dispersers such as sand mills (“Dynomill” manufactured by Shinmaru Enterprises, Inc.), attritors, pearl mills (“DCP mill” manufactured by Eirich), coball mills, etc., wet jet mills (“Genus PY” manufactured by Genus, Sugino) Machine-less “Starburst”, Nanomizer “Nanomizer”, etc., M-Technica “Claire SS-5”, Nara Machinery “MICROS” and other medialess dispersers, and other roll mills. The apparatus to be used is not limited to these, but from the viewpoint of processing efficiency and productivity, it is preferable to use a mixer or a media-type disperser. Moreover, it is preferable to use what gave the metal mixing prevention process from an apparatus.

Examples of the step of aggregating the carbon material on which the dispersant has acted in the liquid to obtain aggregated particles include a method of heating and / or reducing the pressure of the above-mentioned treated product to distill off the solvent. Further, as a method of reducing the solubility or dispersibility of the dispersant on the surface of the carbon material with respect to the solvent and aggregating it, the above-mentioned treated slurry is mixed with a solvent having a relative dielectric constant of less than 15, more preferably 10 or less. The method of aggregating is mentioned. The solvent having a relative dielectric constant of less than 15 is not particularly limited. For example, methyl isobutyl ketone (relative dielectric constant: 13.1), ethyl acetate (6.0), butyl acetate (5.0), Examples include diethyl ether (4.2), xylene (2.3), toluene (2.2), heptane (1.9), hexane (1.9), pentane (1.8) and the like.
These aggregates are taken out by filtration or centrifugation. The obtained processed product can be used as it is, but it is preferable to use it after washing, drying and grinding.

  In addition, for example, with respect to the treatment in an aqueous system, as a step of causing the dispersant to act on the carbon material (for example, adsorption), a dispersant containing a phthalocyanine derivative having an acidic functional group, a carbon material as a conductive auxiliary agent, and water are used. Mix and allow the dispersant to act (eg adsorb) on the carbon material. In particular, a dispersing agent including a phthalocyanine derivative having an acidic functional group is completely or partially dissolved in water or a basic aqueous solution, and a carbon material as a conductive assistant is added to the solution to be mixed and dispersed. These dispersants are preferably allowed to act (for example, adsorb) on the carbon material. The water is preferably ion-exchanged water or purified water. In order to increase the solubility of the dispersant, the pH of the treatment liquid is preferably 7 <pH <14, more preferably 7 <pH ≦ 11, and particularly preferably 8 ≦ pH ≦ 10. A base is added to make the pH of the treatment solution basic. As the base, there can be used a compound which shows basicity when dissolved in water, such as metal hydroxides such as alkali metals, salts obtained by the reaction of a weak acid and a strong base, ammonia, organic amines and the like.

  In addition, as a device for causing the dispersant to act on the carbon material (for example, adsorption) while mixing and dispersing the carbon material in the solvent, the same device as the treatment in the organic solvent system can be used. From the viewpoint of processing efficiency and productivity, it is preferable to use a mixer or a media-type disperser. Moreover, it is preferable to use what gave the metal mixing prevention process from an apparatus.

  Examples of the step of aggregating the carbon material on which the dispersant has acted in the liquid to obtain aggregated particles include a method of distilling off the water by heating and / or reducing the pressure of the treated material. In addition, as a method of aggregating the dispersant on the surface of the carbon material by lowering the solubility or dispersibility in water, the treatment solution is neutralized or acidified to agglomerate, or an inorganic material such as sodium chloride is used. Examples thereof include a method of adding a salt to salt out and agglomerate the dispersant on the surface of the carbon material, and a method of adding an organic amine or an organic amine salt to agglomerate. Among them, a method of aggregating by neutralizing or acidifying the pH of the treatment liquid and a method of aggregating by adding an organic amine or a salt of organic amine are preferable.

  An acid is added for neutralization or acidification. Examples of acids that can be used include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, salts of inorganic compounds obtained by the reaction of strong acids and weak bases, organic acids such as carboxylic acids and sulfonic acids, and compounds that exhibit acidity when dissolved in water. it can. Of these, volatile carboxylic acids and hydrochloric acid are preferably used.

  In addition, as the organic amine and the organic amine salt, it is preferable to use an organic amine or a salt having a lower solubility in water than the base used in the step of causing the dispersant to act on the carbon material.

  The agglomerated particles are preferably subjected to filtration, centrifugation, and washing steps to form a carbon material as a conductive aid that has been previously treated with a phthalocyanine derivative having an acidic functional group. Moreover, the carbon material as a conductive support agent obtained by treating the obtained phthalocyanine derivative having an acidic functional group in advance can be used after drying.

<Lithium secondary battery>
Next, a lithium secondary battery using the composition of the present invention will be described.
The lithium 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 an electrolyte containing lithium. An electrode base layer may be formed between the positive electrode mixture layer and the current collector, or between the negative electrode mixture layer and the current collector.

  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.

  Examples of the method for forming the electrode base layer on the current collector include a method of applying the electrode base paste described above to the electrode current collector and drying. The film thickness of the electrode underlayer is not particularly limited as long as the conductivity and adhesion are maintained, but is generally 0.05 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less. It is.

  The electrode mixture layer is formed on the current collector by directly applying the electrode mixture paste described above on the current collector and drying the electrode mixture layer, and after forming the electrode base layer on the current collector. The method of apply | coating material paste and drying is mentioned. In addition, when the electrode mixture layer is formed on the electrode foundation layer, after applying the electrode foundation paste on the current collector, the electrode mixture paste may be applied in a wet state and then dried. good. The thickness of the electrode mixture layer is generally 1 μm or more and 500 μm or less, preferably 10 μm or more and 300 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.

<Electrolyte>
As the electrolytic solution constituting the lithium secondary battery of the present invention, an electrolyte containing lithium is dissolved in a non-aqueous solvent. 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 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, and diethyl carbonate, γ-butyrolactone, γ-valerolactone, and 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, and nitriles such as acetonitrile. These solvents may be used alone or in combination of two or more.

  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 lithium secondary battery using the composition of the present invention is not particularly limited, but it is usually composed of a positive electrode and a negative electrode, and a separator provided as necessary. Paper type, cylindrical type, button type, laminated Various shapes can be formed according to the purpose of use, such as a mold.

[Example]
EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is not limited to an Example. In the examples, “parts” represents “parts by weight” and “%” represents “% by weight”. To measure the particle size distribution of the carbon dispersion, use a dynamic light scattering particle size distribution meter ("MICROTRACK UPA" manufactured by Nikkiso Co., Ltd.). Then, the particle diameter (D50) at 50% was determined. However, the dispersion particle size of the carbon dispersion using carbon nanofibers as the conductive assistant was determined by determination with a grind gauge (according to JIS K5600-2-5). Further, the dispersed particle size of the electrode mixture paste was determined by determination with a grind gauge (according to JIS K5600-2-5).

<Dispersant structure and average number of substituents>
About the dispersing agent used in the Example, the average number of substituents of the phthalocyanine derivative which has an acidic functional group as a dispersing agent was calculated | required as follows.

  As for the sulfonic acid-based phthalocyanine derivative, the average number of substituents per molecule was determined from the elemental analysis of the sulfur component of the free sulfonic acid derivative (Z in the structural formula is a proton). As for salt-forming sulfonic acid derivatives (Z in the structural formula is potassium or lauryl ammonium), the sulfonic acid derivative (free sulfonic acid derivative) before salt formation is taken out at the time of synthesis, and one molecule is obtained in the same manner as above. The average number of substituents per unit was determined.

  For carboxylic acid derivatives, for free carboxylic acid derivatives (Z in the structural formula is proton), sodium hydroxide was added by conductometric titration, stirred for a whole day and night, then back titrated with hydrochloric acid, and acid groups from the neutralization point. The amount was determined. As for the salt-forming carboxylic acid derivative (Z in the structural formula is potassium or lauryl ammonium), the carboxylic acid derivative (free carboxylic acid derivative) before salt formation is taken out at the time of synthesis, and one molecule is obtained in the same manner as above. The average number of substituents per unit was determined.

The dispersant used in the examples is shown in Structure Table 1. The meanings of the abbreviations in the table are as follows.
n ^av : Average number of substituents Z: Salt formation with sulfonic acid group or carboxyl group (counter cation of sulfonic acid anion or carboxylic acid anion)

<Preparation of dispersant-treated carbon>
According to the composition shown in Table 2, a carbon dispersant treatment was performed. Table 2 also shows the dispersant treatment method and the treatment equipment used.
[Dispersant-treated carbon (1), (2)]
Various dispersants were added to 2000 parts of ion-exchanged water. While stirring and mixing with a disper, 25% aqueous ammonia was added to adjust the pH of the liquid to about 10, and the dispersant was completely or partially dissolved. Subsequently, 100 parts of various carbons serving as conductive aids were added and mixed with stirring. At this time, aqueous ammonia was appropriately added to maintain the pH of the treatment liquid in the range of 9.5 to 10.5.
Next, after passing the treated slurry through a strainer with a magnet, a 1N hydrochloric acid aqueous solution was added to adjust the pH of the solution to 2 to 3. At this time, since the viscosity of the liquid rapidly increased, ion-exchanged water was appropriately added. The aggregate was collected by filtration, washed with ion-exchanged water, then dried and pulverized to obtain dispersant-treated carbons (1) and (2).

Examples of carbon include commercially available acetylene black (denka black powder, primary particle size 35 nm, specific surface area 68 m ² / g, manufactured by Denki Kagaku Kogyo), commercially available ketjen black (EC-300J, specific surface area 800 m ² / g). , Manufactured by Akzo) or commercially available carbon nanofiber (CNF) (product name “VGCF”, fiber length 10 to 20 μm, fiber diameter 150 nm, specific surface area 13 m ² / g, manufactured by Showa Denko KK). .

[Dispersant-treated carbon (3)]
Dispersing agent prepared by charging 100 parts of carbon to be conductive aid, 3 parts of dispersing agent S, and N-methyl-2-pyrrolidone (NMP) in an amount of 10% with respect to the dispersing agent and treating with an attritor Treated carbon (3) was obtained.
As the carbon, commercially available carbon nanofiber (CNF) (product name “VGCF”, fiber length 10 to 20 μm, fiber diameter 150 nm, specific surface area 13 m ² / g, manufactured by Showa Denko KK) was used.

<Evaluation of wettability of carbon with and without dispersion treatment>
Various carbons not treated with the dispersant and various carbons treated with the dispersant were dried at 80 ° C. under reduced pressure for 10 hours. Subsequently, the dried product was pulverized with an agate mortar and further dried under reduced pressure at 80 ° C. for 12 hours. The obtained dried product was pulverized again with an agate mortar and then loaded with 500 kgf / cm ² with a tablet molding machine (Specac) to produce carbon pellets (diameter 10 mm, thickness 0.5 mm). A droplet in which ethylene carbonate and diethyl carbonate were mixed 1: 1 was dropped on this pellet with a microsyringe, and the time for the droplet to penetrate the pellet was measured. This measurement was performed 5 times for each sample, and those whose average permeation time was less than 1 second was “◎”, those that were 1 second or more and less than 5 seconds were “◯”, 5 seconds or more and 10 seconds. Those that were less than “Δ” were those that were 10 seconds or longer, and “x”.
The results of carbon wettability evaluation with and without dispersant treatment are shown in Table 2.

  In the carbon treated with the dispersant of the present invention, the wettability with respect to the electrolytic solution was improved as compared with the carbon not treated with the dispersant.

<Preparation of carbon dispersion for conductive aid>
[Carbon dispersions 1-7, 10-21]
In accordance with the composition shown in Table 3 and Table 4, 89.5 parts of various solvents and 0.5 part of any of dispersants B to K, M to O, and Q to S are charged into a glass bottle and dispersed by stirring and mixing. The agent was completely or partially dissolved. Next, 10 parts of various carbons serving as conductive aids were added, and zirconia beads were further added as media, and then dispersed with a paint shaker.
The obtained dispersion was thoroughly stirred with a stirring blade equipped with a magnet, and then passed through a filter having an opening of 20 μm to obtain various carbon dispersions.

As a commercially available acetylene black (denka black powder, primary particle size 35 nm, specific surface area 68 m ² / g, manufactured by Denki Kagaku Kogyo Co., Ltd.), or furnace black (Super-PLi, primary particle size 40 nm, specific surface area 62 m) ² / g, manufactured by TIMCAL) was used.

[Carbon dispersion 8, 9, 22]
According to the composition shown in Table 3 and Table 4, N8.5--8,99.7 parts of N-methylpyrrolidone (NMP) in a glass bottle and any one of dispersant-treated carbons (1) to (3) shown in Table 2 10 After 3 to 11.5 parts were charged and stirred and mixed, zirconia beads were further added as a medium and dispersed with a paint shaker.
The obtained dispersion was thoroughly stirred with a stirring blade equipped with a magnet, and then passed through a filter having an opening of 20 μm to obtain various carbon dispersions.
Examples of carbon include commercially available acetylene black (DENKA BLACK FX-35, primary particle size 23 nm, specific surface area 133 m ² / g, manufactured by Denki Kagaku Kogyo Co., Ltd.), ketjen black (EC-300J, specific surface area 800 m ² / g, Akzo). Or carbon nanofiber CNF (product name “VGCF”, fiber length 10-20 μm, fiber diameter 150 nm, specific surface area 13 m ² / g, Showa Denko KK).

[Carbon dispersions 23 and 28]
According to the composition shown in Table 4, after adding 93 parts of N-methylpyrrolidone (NMP) and 7 parts of various carbons as a conductive aid to a glass bottle, and further adding zirconia beads as a medium, dispersed with a paint shaker, Various carbon dispersions were obtained.
As carbon, commercially available acetylene black (denka black powder, primary particle size 35 nm, specific surface area 68 m ² / g, manufactured by Denki Kagaku Kogyo Co., Ltd.) or furnace black (Super-PLi, primary particle size 40 nm, specific surface area) 62 m ² / g, manufactured by TIMCAL) was used.

[Carbon dispersion 24-26]
According to the composition shown in Table 4, in a glass bottle, 89.5 parts of N-methyl-2-pyrrolidone (MNP) and 0.5 part of a surfactant or a dispersing resin as a dispersing agent are charged, and the dispersing agent is mixed and stirred. Dissolved. Next, 10 parts of acetylene black (Denka black powder product, primary particle size 35 nm, specific surface area 68 m ² / g, manufactured by Denki Kagaku Kogyo Co., Ltd.) serving as a conductive auxiliary agent was added, and after adding zirconia beads as a medium, Dispersion was performed with a paint shaker to obtain a carbon dispersion.
As the surfactant, a nonionic surfactant (Emulgen A-60, polyoxyethylene derivative, manufactured by Kao Corporation) or an anionic surfactant (Demol N, β-naphthalenesulfonic acid-formalin condensate sodium) Any of salt and Kao) was used.
As the dispersion resin, polyvinylpyrrolidone (weight average molecular weight: about 80,000, manufactured by Nippon Shokubai Co., Ltd.) was used.

[Carbon dispersion 27, 29, 30]
In accordance with the composition shown in Table 4, 89.5 parts of N-methyl-2-pyrrolidone (MNP) and 0.5 part of any one of dispersants A, L, and P are charged into a glass bottle, and the dispersant is stirred and mixed. Completely or partially dissolved. Next, 10 parts of various carbons to be conductive assistants were added, zirconia beads were further added as media, and then dispersed with a paint shaker to obtain various carbon dispersions.
As carbon, commercially available acetylene black (denka black powder, primary particle size 35 nm, specific surface area 68 m ² / g, manufactured by Denki Kagaku Kogyo Co., Ltd.) or furnace black (Super-PLi, primary particle size 40 nm, specific surface area) 62 m ² / g, manufactured by TIMCAL) was used.

<Evaluation of wettability of dispersed carbon>
For the carbon dispersions 1 to 3, 7, 10 to 21, 23, and 28, carbon wettability evaluation after the dispersion treatment was performed.

The solvent of each carbon dispersion was distilled off under reduced pressure using an evaporator, and the obtained residue was dried under reduced pressure at 80 ° C. for 10 hours. Subsequently, the dried product was pulverized with an agate mortar and further dried under reduced pressure at 80 ° C. for 12 hours. The obtained dried product was pulverized again with an agate mortar and then loaded with 500 kgf / cm ² with a tablet molding machine (Specac) to produce carbon pellets (diameter 10 mm, thickness 0.5 mm). A droplet in which ethylene carbonate and diethyl carbonate were mixed 1: 1 was dropped on this pellet with a microsyringe, and the time for the droplet to penetrate the pellet was measured. This measurement was performed 5 times for each sample, and those whose average permeation time was less than 1 second was “◎”, those that were 1 second or more and less than 5 seconds were “◯”, 5 seconds or more and 10 seconds. Those that were less than “△” were those that were 10 seconds or longer, and “”.

The compositions of the carbon dispersion are shown in Tables 3 and 4. In addition, Table 5 shows the dispersion evaluation results and the wettability evaluation results. The meanings of the abbreviations in the table are as follows.
DN: number of solvent donors NMP: N-methyl-2-pyrrolidone DMSO: dimethyl sulfoxide DMF: N, N-dimethylformamide

カーボン分散（２２）の粒度は、グラインドゲージによる判定。

The particle size of the carbon dispersion (22) is determined by a grind gauge.

  The carbon dispersion using the dispersant of the present invention (dispersions 1 to 22, 27, 29, and 30) is obtained by dispersing only untreated carbon in a solvent (dispersions 21 and 26), or a general interface. It can be seen that the dispersibility is better, the viscosity of the dispersion is lower, and the dispersion particle size is smaller than when the activator is used (dispersions 23 and 28). Even when the dispersant of the present invention was used, the dispersion superiority of the dispersions 27, 29, and 30 over the case where a general surfactant was used was reduced.

  Furthermore, dispersions 1-22 also had good dispersion stability with time (50 ° C. × 3 days), and neither thickening nor aggregation was observed.

<Preparation of positive electrode mixture paste for lithium secondary battery (active material: lithium cobaltate)>
[Examples 1-3, 6, 8-15]
90 parts of lithium cobaltate LiCoO ₂ (HLC-22, average particle size 6.6 μm, specific surface area 0.62 m ² / g, manufactured by Honjo Chemical Co.) as a positive electrode active material, polyvinylidene fluoride (KF polymer, manufactured by Kureha Co., Ltd.) as a binder ) 4.75 parts, 21.9 parts of N-methyl-2-pyrrolidone as a solvent were kneaded with a planetary mixer, and then 50 parts (5 parts as carbon amount) of the carbon dispersion prepared above were added, Further, the mixture was kneaded to obtain a positive electrode mixture paste. The carbon dispersion used in each example is shown in Table 6.
[Examples 4 and 5]
90 parts of lithium cobaltate LiCoO ₂ (HLC-22, average particle size 6.6 μm, specific surface area 0.62 m ² / g, manufactured by Honjo Chemical Co.) as a positive electrode active material, polyvinylidene fluoride (KF polymer, manufactured by Kureha Co., Ltd.) as a binder ) 4.75 parts, 21.9 parts of dimethyl sulfoxide as a solvent, or 21.9 parts of dimethylformamide using a planetary mixer, and then 50 parts of either carbon dispersion (5) or (6) prepared above (5 parts as the amount of carbon) was added and further kneaded to obtain a positive electrode mixture paste. The carbon dispersion used in each example is shown in Table 6.
[Example 7]
90 parts of lithium cobaltate LiCoO ₂ (HLC-22, average particle size 6.6 μm, specific surface area 0.62 m ² / g, manufactured by Honjo Chemical Co.) as a positive electrode active material, polyvinylidene fluoride (KF polymer, manufactured by Kureha Co., Ltd.) as a binder ) 4.75 parts, 0.25 parts of dispersant E, 5 parts of acetylene black (Denka black powder, primary particle size 35 nm, specific surface area 68 m ² / g, manufactured by Denki Kagaku Kogyo Co., Ltd.) serving as a conductive auxiliary agent, Then, 36.7 parts of N-methyl-2-pyrrolidone (NMP) as a solvent was kneaded with a planetary mixer, and 30 parts of NMP was further added and kneaded to obtain a positive electrode mixture paste (see Table 6).

[Comparative Example 1]
90 parts of lithium cobaltate LiCoO ₂ (HLC-22, average particle size 6.6 μm, specific surface area 0.62 m ² / g, manufactured by Honjo Chemical Co.) as a positive electrode active material, polyvinylidene fluoride (KF polymer, manufactured by Kureha Co., Ltd.) as a binder ) 5 parts, 0.2 part of N-methyl-2-pyrrolidone (NMP) as a solvent and 71.4 parts of carbon dispersion (23) prepared previously (5 parts as carbon amount), kneaded and positive electrode A composite paste was obtained (see Table 7).
[Comparative Example 2-5]
90 parts of lithium cobaltate LiCoO ₂ (HLC-22, average particle size 6.6 μm, specific surface area 0.62 m ² / g, manufactured by Honjo Chemical Co.) as a positive electrode active material, polyvinylidene fluoride (KF polymer, manufactured by Kureha Co., Ltd.) as a binder ) 4.75 parts, 21.9 parts of N-methyl-2-pyrrolidone (NMP) as a solvent were kneaded by a planetary mixer, and then 50 parts of any of the carbon dispersions prepared previously (5 parts as carbon amount) Was further kneaded to obtain a positive electrode mixture paste. The carbon dispersion used in each comparative example is shown in Table 7.

<Preparation of positive electrode mixture paste for lithium secondary battery (active material: lithium manganate)>
[Example 16-21]
Lithium manganate LiMn ₂ O ₄ (CELLSEED S-LM, average particle size 12 μm, specific surface area 0.48 m ² / g, manufactured by Nippon Chemical Industry Co., Ltd.) 85 parts as a positive electrode active material, polyvinylidene fluoride (KF polymer, Kureha) as a binder 5.6 parts) and 35 parts of the various carbon dispersions prepared above were kneaded with a planetary mixer. Subsequently, 55 parts of various carbon dispersions were added and further kneaded to obtain a positive electrode mixture paste. The carbon dispersion used in each example is shown in Table 8.
[Example 22]
Lithium manganate LiMn ₂ O ₄ (CELLSEED S-LM, average particle size 12 μm, specific surface area 0.48 m ² / g, manufactured by Nippon Chemical Industry Co., Ltd.) 85 parts as a positive electrode active material, polyvinylidene fluoride (KF polymer, Kureha) as a binder 5.7 parts) and 35 parts of the previously prepared carbon dispersion (22) were kneaded with a planetary mixer. Subsequently, 55 parts of carbon dispersion (22) was added and further kneaded to obtain a positive electrode mixture paste (see Table 8).
[Comparative Example 6]
Lithium manganate LiMn ₂ O ₄ (CELLSEED S-LM, average particle size 12 μm, specific surface area 0.48 m ² / g, manufactured by Nippon Chemical Industry Co., Ltd.) 85 parts as a positive electrode active material, polyvinylidene fluoride (KF polymer, Kureha) as a binder 6 parts) and 35 parts of the previously prepared carbon dispersion (28) were kneaded by a planetary mixer. Subsequently, 94 parts of carbon dispersion (28) was added and further kneaded to obtain a positive electrode mixture paste (see Table 8).
[Comparative Examples 7 and 8]
Lithium manganate LiMn ₂ O ₄ (CELLSEED S-LM, average particle size 12 μm, specific surface area 0.48 m ² / g, manufactured by Nippon Chemical Industry Co., Ltd.) 85 parts as a positive electrode active material, polyvinylidene fluoride (KF polymer, Kureha) as a binder 5.6 parts) and 35 parts of the various carbon dispersions prepared above were kneaded with a planetary mixer. Subsequently, 55 parts of various carbon dispersions were added and further kneaded to obtain a positive electrode mixture paste. The carbon dispersion used in each example is shown in Table 8.

<Preparation of positive electrode mixture paste for lithium secondary battery (active material: lithium nickelate)>
[Example 23]
91 parts of lithium nickelate LiNiO ₂ (manufactured by Tanaka Chemical Research Co., Ltd.) as the positive electrode active material, 4.8 parts of polyvinylidene fluoride (KF polymer, manufactured by Kureha Co., Ltd.) as the binder, and 30.9 N-methyl-2-pyrrolidone as the solvent After kneading the part with a planetary mixer, 40 parts of the previously prepared carbon dispersion (21) (4 parts as the amount of carbon) was added and further kneaded to obtain a positive electrode mixture paste (see Table 9).
[Comparative Example 9]
Lithium nickel oxide LiNiO ₂ (Tanaka Chemical Research Co., Ltd.) 91 parts as the positive electrode active material, polyvinylidene fluoride (KF Polymer, manufactured by Kureha Corporation) 4.8 parts, N- methyl-2-pyrrolidone 30.9 as a solvent After kneading the parts with a planetary mixer, 40 parts of the previously prepared carbon dispersion (30) (4 parts as carbon amount) was added and further kneaded to obtain a positive electrode mixture paste (see Table 9).

<Preparation of positive electrode mixture paste for lithium secondary battery (active material: lithium iron phosphate)>
[Example 24]
3. Lithium iron phosphate LiFePO ₄ (average particle size 3.6 μm, specific surface area 15 m ² / g, manufactured by TIANJIN STL ENERGY TECHNOLOGY) as positive electrode active material, 91 parts of polyvinylidene fluoride (KF polymer, manufactured by Kureha) as binder After 8 parts and 30.9 parts of N-methyl-2-pyrrolidone (NMP) as a solvent were kneaded by a planetary mixer, 40 parts of the previously prepared carbon dispersion (7) (4 parts as the amount of carbon) was added, Further, the mixture was kneaded to obtain a positive electrode mixture paste (see Table 9).
[Comparative Example 10]
3. Lithium iron phosphate LiFePO ₄ (average particle size 3.6 μm, specific surface area 15 m ² / g, manufactured by TIANJIN STL ENERGY TECHNOLOGY) as positive electrode active material, 91 parts of polyvinylidene fluoride (KF polymer, manufactured by Kureha) as binder After 8 parts and 30.9 parts of N-methyl-2-pyrrolidone (NMP) as a solvent were kneaded by a planetary mixer, 40 parts of the previously prepared carbon dispersion (27) (4 parts as carbon amount) was added, Further, the mixture was kneaded to obtain a positive electrode mixture paste (see Table 9).

<Preparation of negative electrode mixture paste for lithium secondary battery>
[Examples 25-27, 29-41, Comparative Examples 13, 15, 16]
93 parts of spherical graphite (average particle size of about 10 to 20 μm, manufactured by Nippon Graphite Co., Ltd.) as the negative electrode active material, 4.9 parts of polyvinylidene fluoride (KF polymer, manufactured by Kureha Co.) as the binder, various carbon dispersions prepared previously After 20 parts (2 parts as the amount of carbon black) were kneaded by a planetary mixer, 48.7 parts of N-methyl-2-pyrrolidone was added and further kneaded to obtain a negative electrode mixture paste. The carbon dispersion used in each example is shown in Table 10.
[Comparative Examples 12 and 14]
93 parts of spherical graphite (average particle size of about 10 to 20 μm, manufactured by Nippon Graphite Co., Ltd.) as a negative electrode active material, 5 parts of polyvinylidene fluoride (KF polymer, manufactured by Kureha Co.) as a binder, carbon dispersion (23) prepared earlier Alternatively, 28.6 parts (2 parts as the amount of carbon black) of (28) were kneaded with a planetary mixer, 40.1 parts of N-methyl-2-pyrrolidone was added, and further kneaded to obtain a negative electrode mixture paste ( (See Table 11).
[Example 28]
As a negative electrode active material, 93 parts of spherical graphite (average particle size of about 10 to 20 μm, manufactured by Nippon Graphite Co., Ltd.), 1 part of carboxymethyl cellulose (Sunrose F300MC, manufactured by Nippon Paper Chemicals Co., Ltd.) as a binder, and styrene butadiene rubber (TRD2001, JSR) 3.9 parts), 20 parts of carbon dispersion (4) prepared previously (2 parts as carbon black amount) were kneaded with a planetary mixer, 48.7 parts of ion-exchanged water was added, and further kneaded. And a negative electrode mixture paste (see Table 10).
[Comparative Example 11]
As a negative electrode active material, 93 parts of spherical graphite (average particle size of about 10 to 20 μm, manufactured by Nippon Graphite Co., Ltd.), 1 part of carboxymethyl cellulose (Sunrose F300MC, manufactured by Nippon Paper Chemicals Co., Ltd.) as a binder, and styrene butadiene rubber (TRD2001, JSR) 4 parts), 2 parts of acetylene black (denka black powder product, primary particle size 35 nm, specific surface area 68 m ² / g, manufactured by Denki Kagaku Kogyo Co., Ltd.) as a conductive auxiliary agent and 18 parts of ion exchange water After kneading with a mixer, 48.7 parts of ion-exchanged water was added and further kneaded to obtain a negative electrode mixture paste (see Table 11).

<Preparation of positive electrode for lithium secondary battery>
[Example 1-24, Comparative Example 1-10]
The positive electrode mixture paste prepared above was applied onto a 20 μm thick aluminum foil serving as a current collector using a doctor blade, followed by drying under reduced pressure, and rolling to form a 100 μm thick positive electrode mixture layer. It produced (refer Tables 6-9).
[Examples 42-54, Comparative Examples 17-19]
After applying the positive electrode mixture paste used in Examples 1 to 3, 7, 10 to 12, 14, 17 to 21 and Comparative Examples 1, 5, and 8 to both sides of an aluminum foil having a thickness of 20 μm, heating under reduced pressure was performed. It dried and rolled and produced the positive mix layer (refer Table 12).

<Preparation of negative electrode for lithium secondary battery>
[Examples 25-41 and Comparative Examples 11-16]
After applying the various negative electrode mixture pastes prepared above onto a copper foil having a thickness of 20 μm as a current collector using a doctor blade, drying under reduced pressure and rolling, a negative electrode mixture layer having a thickness of 100 μm was formed. It produced (refer Table 10 and 11).
[Examples 42-54, Comparative Examples 17-19]
The negative electrode mixture paste used in Examples 25-27, 29-32, 34, 37-41 and Comparative Examples 12, 13, 16 was applied to both sides of a copper foil having a thickness of 20 μm, and then dried by heating under reduced pressure. Then, a negative electrode mixture layer was produced by rolling (see Table 12).

<Assembly of lithium secondary battery positive electrode evaluation cell>
[Example 1-24, Comparative Example 1-10]
A separator made of a porous polypropylene film between the working electrode and the counter electrode (# 2400, manufactured by Celgard Co., Ltd.) with the positive electrode produced previously punched into a diameter of 9 mm and used as a working electrode, and a metallic lithium foil (thickness 0.15 mm) as a counter electrode Is inserted and laminated, filled with an electrolyte (nonaqueous electrolyte in which LiPF ₆ is dissolved at a concentration of 1M in a mixed solvent of ethylene carbonate and diethyl carbonate in a ratio of 1: 1), and a bipolar metal cell (Hosen) (HS flat cell). The assembly of the cell was performed in a glove box substituted with argon gas, and a predetermined battery characteristic evaluation was performed after the assembly of the cell (see Tables 13 to 16).

<Assembly of lithium secondary battery negative electrode evaluation cell>
[Examples 25-41 and Comparative Examples 11-16]
A separator made of a porous polypropylene film between the working electrode and the counter electrode (# 2400, manufactured by Celgard Co., Ltd.) with the negative electrode prepared previously punched to a diameter of 9 mm and used as a working electrode, and a metallic lithium foil (thickness 0.15 mm) as a counter electrode Is inserted and laminated, filled with an electrolyte (nonaqueous electrolyte in which LiPF ₆ is dissolved at a concentration of 1M in a mixed solvent of ethylene carbonate and diethyl carbonate in a ratio of 1: 1), and a bipolar metal cell (Hosen) (HS flat cell). The assembly of the cell was performed in a glove box substituted with argon gas, and a predetermined battery characteristic evaluation was performed after the assembly of the cell (see Tables 17 and 18).

<Assembly of metal contamination resistance evaluation cell for lithium battery>
[Examples 42-54, Comparative Examples 17-19]
The positive electrode and negative electrode prepared previously were cut into a width of 54 mm and a length of 500 mm, and wound with a separator made of polyethylene (film thickness 25 μm, width 58 mm, porosity 50%) interposed. This was placed in a battery can and the electrolyte was injected. After injection, the sealing part was sealed to produce a battery (see Table 12).

In this example and comparative example, LiPF ₆ was dissolved at a concentration of 1M in a solvent in which ethylene carbonate and diethyl carbonate were mixed in a 1: 1 ratio as an electrolytic solution in order to evaluate battery resistance when metal components were mixed. Furthermore, Cu (BF ₄ ) ₂ as a copper ion source was added at 10 ppm, or Fe (CF ₃ SO ₂ ) ₂ was added as an iron ion source at 50 ppm.

<Characteristic evaluation of lithium secondary battery positive electrode>
[Charge / Discharge Cycle Characteristics Example 1-23, Comparative Example 1-9]
The produced battery evaluation cell was fully charged at a constant current and constant voltage charge (upper limit voltage 4.2 V) at a room temperature (25 ° C.) with a charge rate of 0.2 C and 1.0 C, and at a constant current at the same rate as during charging. Charge / discharge for discharging to a discharge lower limit voltage of 3.0V is defined as one cycle (charge / discharge interval rest time 30 minutes), and this cycle is performed for a total of 20 cycles to evaluate charge / discharge cycle characteristics (Evaluation apparatus: SM-8 manufactured by Hokuto Denko Co., Ltd.) ) Moreover, the cell after evaluation was decomposed | disassembled and the external appearance of the electrode coating film was confirmed visually. The evaluation results are shown in Tables 13-16.

[Charge / Discharge Cycle Characteristics Example 24, Comparative Example 10]
The produced battery evaluation cell is fully charged at a constant current and constant voltage charge (upper limit voltage 4.5 V) at room temperature (25 ° C.) and at a charge rate of 0.2 C and 1.0 C, and at a constant current at the same rate as during charging. Charging / discharging for discharging to a lower discharge limit voltage of 2.0 V is defined as one cycle (charging / discharging interval rest time 30 minutes), and this cycle is performed for a total of 20 cycles, and charging / discharging cycle characteristics evaluation (evaluation apparatus: SM-8 manufactured by Hokuto Denko Co., Ltd. ) Moreover, the cell after evaluation was decomposed | disassembled and the external appearance of the electrode coating film was confirmed visually. The evaluation results are shown in Table 16.

[DC Internal Resistance Measurement Examples 1-3, 6, 7, 10, 11, 19-21, 23, 24 Comparative Examples 1-6, 8-10]
The battery evaluation cell thus prepared was fully charged at a constant current and constant voltage charge (upper limit voltage 4.2 V) at room temperature (25 ° C.) and a charge rate of 0.2 C, and 0.1 C, 0.2 C, 0.5 C, 1. After discharging at a constant current of 0 C for 5 seconds, the battery voltage was measured. The voltage value was plotted against the current value, and the slope of the obtained linear relationship was defined as the internal resistance. Although an evaluation result is shown to Tables 13-16, about the case where lithium cobaltate was used as a positive electrode active material, it showed as a relative value when the internal resistance measured value of Example 6 is set to 100. About the case where lithium manganate was used as a positive electrode active material, it showed as a relative value when the internal resistance measured value of Example 20 is set to 100. Moreover, about the case where lithium nickelate was used as a positive electrode active material, it showed as a relative value when the internal resistance measured value of Example 23 is set to 100. Moreover, about what used lithium iron phosphate as a polar active material, it showed as a relative value when the internal resistance measured value of Example 24 is set to 100.

As can be seen from Tables 6 to 9 and Tables 13 to 16, in the examples, the dispersibility and the temporal stability of the positive electrode mixture paste were improved as compared with the comparative examples. Further, as compared with the comparative example, the internal resistance was reduced and the battery capacity and the 20 cycle capacity maintenance rate were improved.
<Characteristic evaluation of lithium secondary battery negative electrode>
[Charge / Discharge Cycle Characteristics Example 25-41, Comparative Example 11-16]
The battery evaluation cell thus prepared was fully charged at 0.05 V by constant current and constant voltage charging at room temperature (25 ° C.), charging rate of 0.2 C and 1.0 C, and the voltage was constant at the same rate as charging. Charging / discharging for discharging until 1.5V was taken as one cycle (charging / discharging interval rest time 30 minutes).

  First, this charge / discharge operation was performed five times, and the discharge capacity at the sixth time was set as an initial value. Then, this cycle was performed 20 times in total, and charge / discharge cycle characteristic evaluation (evaluation apparatus: SM-8 manufactured by Hokuto Denko) was performed. Moreover, the cell after evaluation was decomposed | disassembled and the presence or absence of the electrode coating film defect was confirmed visually. The evaluation results are shown in Table 17 and Table 18.

  As can be seen from Tables 10 to 11 and Tables 17 to 18, in the examples, the dispersibility and the temporal stability of the negative electrode mixture paste were improved as compared with the comparative examples. Moreover, compared with the comparative example, the battery capacity and the 20 cycle capacity retention rate were improved.

<Evaluation of metal contamination resistance of lithium batteries>
[Charge / Discharge Cycle Characteristics Examples 42-54, Comparative Examples 17-19]
The prepared battery is fully charged at a constant current and constant voltage charge (upper limit voltage 4.0 V) at room temperature (25 ° C.) and a charge rate of 1.0 C until the voltage reaches 2.75 V at a constant current at the same rate as during charging. Charging / discharging for discharging was defined as one cycle (charging / discharging interval pause time 30 minutes), and this cycle was performed for a total of 20 cycles or more. As an evaluation, the capacity retention rate is obtained from the initial discharge capacity and the discharge capacity at the 20th cycle. When the capacity retention rate is 95% or more, “◎”, when 90% or more and less than 95% are “◯”, 85% More than 90% is “△” and less than 85% is “▲”. The evaluation results are shown in Table 19.

In the batteries of Examples 42 to 54 and Comparative Examples 17 and 18, the charge / discharge cycle could be repeated stably for 20 cycles. However, in Comparative Examples 17 and 18, the capacity retention rate tended to be lower than in the Examples. In addition, when the functional group of the dispersant was free sulfonic acid (—SO ₃ H) or free carboxylic acid (—COOH), the capacity retention rate during 20 cycles tended to increase. On the other hand, in Comparative Example 19, charging / discharging became impossible in 5 cycles. When the cell was disassembled after the evaluation, a short circuit occurred due to dendritic metal deposits.

Claims (11)

  A battery composition comprising a phthalocyanine derivative as a dispersant having an acidic functional group having an average number of substituents of 0.4 to 2.9, and a carbon material as a conductive additive. Acidic functional group is sulfonic acid group _(-SO 3 H) or the composition for a battery of claim 1, wherein the carboxyl group (-COOH).   The battery composition according to claim 1, wherein the acidic functional group is an ammonium sulfonate salt or an ammonium carboxylate salt.   The battery composition according to claim 1, wherein the acidic functional group is a sulfonic acid metal salt or a carboxylic acid metal salt.   The battery composition according to any one of claims 1 to 4, further comprising a solvent. The battery composition according to any one of claims 1 to 5, wherein a dispersed particle diameter (D ₅₀ ) of the carbon material as the conductive assistant is 2 µm or less.   The battery composition according to any one of claims 1 to 6, further comprising a binder component.   The battery composition according to claim 7, wherein the binder component is a polymer compound containing a fluorine atom in the molecule.   The battery composition according to any one of claims 5 to 8, wherein the solvent is N-methylpyrrolidone.   The battery composition according to any one of claims 1 to 9, further comprising a positive electrode active material or a negative electrode active material.   A lithium secondary battery comprising 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 an electrolyte containing lithium, wherein the positive electrode mixture layer or The lithium secondary battery, wherein the negative electrode mixture layer is formed using the battery composition according to claim 9.