JP2019117725A - Conductive composition, power collector with ground layer for electricity storage device, electrode for electricity storage device, and electricity storage device - Google Patents

Abstract

To provide a conductive composition excellent in output properties or the like of an electricity storage device, because conductivity during normal operation is excellent, for forming the electricity storage device with functions for increasing internal resistance when internal temperature of the electricity device increases (for example nonaqueous electrolyte secondary batter (for example a lithium ion secondary battery), an electric double layer capacitor, a lithium ion capacitor, or the like), and excellent in conductivity and safety function of the electricity storage device.SOLUTION: The above described problem is solved by a conductive composition containing a conductive carbon material (A), a water dispersion olefin resin fine particle (B), a polyvalent cationic compound (C), and an aqueous liquid medium (D), in which solid component mass of the polyvalent cationic compound (C) is 0.01 to 0.5 mass%, and glossiness value of a coated film coated by the conductive composition is 1 to 10.SELECTED DRAWING: None

Description

  The present invention relates to a conductive composition, an electrode for a storage device obtained using the composition, and a storage device obtained using the electrode. More specifically, the present invention relates to a conductive composition having a function of increasing the internal resistance of the storage device when the temperature of the storage device rises, an electrode for the storage device, and the storage device.

  In recent years, small portable electronic devices such as digital cameras and cellular phones have come into widespread use. In these electronic devices, it is always required to minimize the volume and to reduce the weight, and also in the mounted battery, it is required to realize a small, lightweight and large-capacity battery. In particular, lithium ion secondary batteries can achieve large energy density compared to water-based secondary batteries such as lead storage batteries, NiCd batteries, nickel hydrogen batteries etc., so their importance as power sources for personal computers and portable terminals are increasing. Furthermore, they are expected to be preferably used as high-output power sources for on-vehicle mounting.

  While lithium ion secondary batteries have the advantage of high energy density, the use of non-aqueous electrolytes requires adequate measures for safety. In recent years, securing of safety has become a major issue in response to the increase in size and capacity of batteries. In particular, when the battery temperature rises abnormally and rapidly due to a short circuit or the like inside the battery, it is difficult to regulate heat generation only with the safety mechanism provided outside the battery, and there is a risk of ignition. is there.

  Patent Document 1 describes a method of joining an electron conductive material having a function of a positive temperature coefficient resistor (hereinafter referred to as PTC) to a current collector. However, since the thickness of the electron conductive material is as large as 50 μm, there is a problem that the energy density of the whole battery is lowered.

  Patent Document 2 discloses that any one of a positive electrode, a negative electrode, and a non-aqueous electrolyte has PTC characteristics. However, to impart PTC properties to them, it is necessary to add a large amount of additives that do not contribute to the battery capacity, which causes a decrease in energy density.

  Patent Document 3 describes a method of providing a conductive layer composed of a crystalline thermoplastic resin, a conductive agent, and a binder on the surface of a current collector. In the conductive layer, when the temperature in the battery exceeds the melting point of the crystalline thermoplastic resin, the resistance of the conductive layer is increased, and the current between the current collector and the active material is interrupted. However, there is a problem that the internal resistance during normal operation of the battery is high, and the output characteristics of the battery are degraded.

  Patent Document 4 describes a method of providing a conductive layer comprising polyvinylidene fluoride and a conductive agent on the surface of a current collector, and heating the current collector provided with the conductive layer at a temperature exceeding 120 ° C. However, in addition to the addition of a heat treatment step, there is a problem that the increase in resistance when the temperature in the battery rises is not sufficient.

JP 10-241665 A JP-A-11-329503 JP 2001-357854 A JP 2012-104422 A

  The object of the present invention is to improve the output characteristics of the storage device and the like because it is excellent in conductivity during normal operation, and to have a function of increasing the internal resistance when the internal temperature of the storage device rises (for example, A conductive composition for forming a non-aqueous electrolyte secondary battery (for example, lithium ion secondary battery), an electric double layer capacitor, a lithium ion capacitor, etc., which is excellent in the conductivity and safety function of a storage device. It is providing a composition.

The present invention is a conductive composition comprising a conductive carbon material (A), water-dispersed olefin resin fine particles (B), a polyvalent cationic compound (C), and an aqueous liquid medium (D), The resistance of the current collector increases at the time of heat generation of the power storage device, and the current is shut off to prevent ignition of the power storage device and the like.
Furthermore, the presence of the polyvalent cationic compound (C) in the conductive composition allows the polyvalent cationic compound (C) to intervene between the water-dispersed olefin resin fine particles and the conductive carbon material. It has been found that the effect of cutting the contact between conductive carbon materials by the volume expansion of the water-dispersed olefin-based resin fine particles that occurs when the storage device generates heat is enhanced, and the present invention has been achieved.
In addition, since the resin that increases the internal resistance during heat generation is a water-dispersed olefin-based resin fine particle, the internal resistance during normal operation can be reduced without impairing the conductivity of the carbon material (A), and output characteristics and repeated Cycle characteristics can be improved.

  By the above effects, it has been found that the output characteristics and the charge / discharge repeating cycle characteristics can be improved during normal operation, and the safety of the electricity storage device in the event of internal short circuit or overcharge can be dramatically improved.

That is, the present invention provides a conductive composition comprising a conductive carbon material (A), a water-dispersed olefin-based resin fine particle (B), a multivalent cationic compound (C), and an aqueous liquid medium (D). In the conductive composition, the solid content mass of the multivalent cationic compound (C) is 0.01 to 0.5% by mass in the solid content of the conductive composition. The present invention relates to a conductive composition characterized in that the gloss value of a coated film on which an article is applied is 1 to 10.
The present invention also relates to the conductive composition described above, wherein the multivalent cationic compound (C) is a water-soluble multivalent metal compound or a water-dispersed fine particle exhibiting a positive zeta potential.
Further, the present invention relates to the conductive composition, wherein the water-dispersed olefin resin fine particles (C) exhibit a negative zeta potential.
Further, the present invention is characterized in that the mass ratio (B1) / (A) of the conductive carbon material (A) to the solid content (B1) of the water-dispersed olefin resin fine particles (B) is 1 to 5 The present invention relates to the above conductive composition.
Furthermore, the present invention relates to the conductive composition, which further comprises 10 to 50% by mass of the water-soluble resin (E) in the solid content of the conductive composition.
Further, the present invention relates to the above-mentioned conductive composition, which is for forming a base layer of an electrode for a storage device.
The present invention also relates to a current collector with a base layer for a storage battery device, having a current collector and a base layer formed of the conductive composition.
The present invention also provides an electricity storage device comprising a current collector, an underlayer formed of the conductive composition, and a composite material layer formed of an electrode-forming composition containing an electrode active material and a binder. It relates to an electrode.
The present invention also relates to a storage device comprising a positive electrode, a negative electrode, and an electrolytic solution, wherein at least one of the positive electrode and the negative electrode is the electrode for a storage device.

  The conductivity of the carbon material is impaired by including the conductive carbon material (A), the water-dispersed olefin resin fine particles (B), the multivalent cationic compound (C), and the aqueous liquid medium (D) Instead, it is possible to provide a power storage device having a function of increasing the internal resistance when the internal temperature of the power storage device rises.

<Conductive composition>
As described above, the conductive composition of the present invention can be used for forming an underlayer of an electricity storage device. The conductive composition contains a conductive carbon material (A), water-dispersed olefin resin fine particles (B), a polyvalent cationic compound (C), and an aqueous liquid medium (D). In the case of dispersing the conductive carbon material (A) in the conductive composition, it is preferable to use a surfactant from the viewpoint of solid content of the conductive composition, and it is preferable to use the surfactant resistance and the inside of the storage device during heat generation. It is more preferable to use a water-soluble resin (E) from the viewpoint of increase in resistance.

  The solid content mass of the polyvalent cationic compound (C) contained in the conductive composition is 0.01 to 0.5 mass% in the solid content of the conductive composition, and preferably 0.02 to 0. It is 2% by mass, more preferably 0.03 to 0.15% by mass. If the addition amount of the multivalent cationic compound (C) is too small, the bonding between the water-dispersed olefin-based resin fine particles (B) and the conductive carbon material (A) is weak, and the internal resistance of the electricity storage device increases during heat generation. When the improvement effect is low and the addition amount is too large, the bonding strength between the conductive carbon materials (A) becomes strong, cutting of the carbon materials becomes difficult, and the stability of the conductive composition deteriorates. There is.

  The mass ratio (B1) / (A) of the conductive carbon material (A) to the solid content mass (B2) of the water-dispersed olefin resin fine particles (B) contained in the conductive composition is the internal resistance and the conductivity. And from the viewpoint of the increase in internal resistance of the storage device at the time of heat generation, it is preferably 1 to 5, more preferably 1.5 to 4, and still more preferably 2 to 3.

  It is preferable that the conductive composition contain a water-soluble resin (E) from the viewpoints of the adhesion of the electrode, the resistance to the electrolytic solution, and the increase in internal resistance of the storage device at the time of heat generation. The content of the water-soluble resin (E) is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and still more preferably 20% of the total 100% by mass of the solid content of the conductive composition. It is -40 mass%.

  The total amount of the conductive carbon material (A), the water-dispersed olefin resin fine particles (B) and the water-soluble resin (E) in the total 100% by mass of the solid content of the conductive composition is the internal resistance and the conductivity and From the viewpoint of increase in internal resistance of the storage device during heat generation, it is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more. Arbitrary components may be added to the above composition as required.

  The optional component is not particularly limited. For example, a material that adsorbs or consumes an acid generated by a reaction of an electrolytic solution, a material that generates a gas when the temperature exceeds a predetermined temperature, an inorganic PTC material, and polyolefin resin particles A material or the like may be added to hold the conductive path after the process.

As a material which adsorbs the acid generated by the reaction of the electrolytic solution, for example, magnesium oxide (MgO), aluminum oxide (Al ₂ O ₃ ), boron oxide (B ₂ O ₃ ), gallium oxide (Ga ₂ O ₃ ), Indium oxide (In ₂ O ₃ ) and the like can be mentioned.

  As materials that consume the acid generated by the reaction of the electrolytic solution, metal carbonates such as magnesium carbonate and calcium carbonate, sodium carboxylate, potassium carboxylate, sodium sulfonate, potassium sulfonate, sodium benzoate, potassium benzoate and the like Metal silicates, sodium silicate, potassium silicate, aluminum silicate, magnesium silicate, silicates such as silicon dioxide, and alkaline hydroxides such as magnesium hydroxide.

  Examples of the material that generates a gas when the temperature exceeds a predetermined temperature include lithium carbonate, zinc carbonate, lead carbonate, carbonates such as strontium carbonate, and expanded graphite.

Examples of the inorganic PTC material include BaTiMO ₂ (M is Cr, Pb, Ca, Sr, Ce, Mn, La, Y, Nb, and one or more elements of Nd), and the like.

  As a material holding the conductive path after the volume expansion of the polyolefin resin fine particles, cellulose nanofibers and the like can be mentioned.

  Moreover, although the appropriate viscosity of the conductive composition depends on the coating method of the conductive composition, it is generally preferable to be 10 mPa · s or more and 30,000 mPa · s or less.

<Conductive carbon material (A)>
The conductive carbon material (A) in the present invention is not particularly limited as to the conductive carbon material, but graphite, carbon black, conductive carbon fibers (carbon nanotubes, carbon nanofibers, carbon fibers) And fullerenes can be used alone or in combination of two or more. The use of carbon black is preferred in view of conductivity, availability and cost.

  As carbon black, furnace black which is produced by continuous thermal decomposition of gaseous or liquid raw materials in a reaction furnace, especially ketjen black made from ethylene heavy oil, raw material gas is burned and the flame is obtained from the bottom of the channel steel Channel black which has been rapidly cooled and deposited, thermal black which is obtained by periodically repeating combustion and thermal decomposition using gas as a raw material, in particular various kinds of acetylene black as a raw material such as acetylene gas alone or It can be used together with more than types. In addition, oxidized carbon black, hollow carbon, and the like that are commonly used can also be used.

Commercially available carbon blacks include, for example, TOKA BLACK # 4300, # 4400, # 4500, # 5500 etc. (Tokai Carbon Co., Ltd., furnace black), PINTEX L, etc. (Degussa company, furnace black), Raven 7000, 5750, Conductex SC ULTRA for 5250, 5000 ULTRA III, 5000 ULTRA, etc.
, Conductex 975 ULTRA, etc., PUER BLACK 100, 115, 2
05 mag (Columbian, furnace black), # 2350, # 2400B, # 2600B, # 3050B, # 3030B, # 3230B, # 3350B, # 3400B, # 5400B, etc. (Mitsubishi Chemical Corporation, furnace black) MONARCH 1400, 1300, 900, Vulcan XC-72R, BlackPearls 2000, etc. (Cabot made by Furnace Black), Ensaco 250 G, Ensaco 260 G, Ensaco 350 G, SuperP-Li (made by TIMCAL), ketjen black EC-300J, EC-600 JD (made by Akzo), Denka black, Denka black HS-100, FX-35 (Denka Co., Ltd., acetylene black), etc., examples of the graphite include artificial graphite and flake graphite, lumps Graphite, including but natural graphite such as earthy graphite, is not limited thereto, may be used in combination of two or more.

The specific surface area of the carbon black used in the present invention is advantageous for lowering the internal resistance of the electrode because the contact point between particles increases as the value increases. Specifically, from the viewpoint of conductivity and availability, the specific surface area (BET) determined from the adsorption amount of nitrogen is preferably 20 to 1500 m ² / g, more preferably 40 to 1500 m ² / g. It is desirable to use one. Further, the particle size of carbon black to be used is preferably 0.005 to 1 μm as a primary particle size, and particularly preferably 0.01 to 0.2 μm. However, the primary particle size referred to here is an average of particle sizes measured with an electron microscope or the like.

  The conductive carbon material (A) used in the present invention forms an aggregation structure with the water-dispersed olefin resin fine particles (B) through the multivalent cationic compound (C), and the carbon material by the volume expansion of the water-dispersed olefin resin fine particles The conductive carbon material (A) is preferably anionic since it is considered to enhance the cutting effect of each other.

<Water-dispersed olefin-based fine particles (B)>
The water-dispersed olefin resin fine particles (B) of the present invention are generally referred to as an aqueous emulsion, and the resin particles are dispersed in the form of fine particles without being dissolved in water.

  The water-dispersed olefin-based resin fine particles (B) may be a combination of two or more types of water-dispersed olefin-based resin fine particles (B) as necessary, and a combination of two or more types of water-dispersed resin fine particles other than the olefin-based resin fine particles It is good. The water-dispersed resin fine particles other than the olefin-based resin fine particles are not particularly limited, but (meth) acrylic emulsions, nitrile emulsions, urethane emulsions, diene emulsions (SBR (styrene butadiene rubber), etc.), fluorine emulsions (PVDF ( Polyvinylidene fluoride), PTFE (polytetrafluoroethylene), etc. may be mentioned.

  The water-dispersed olefin-based resin fine particle is a resin which can expand the volume of the resin within the range of 80 to 180 ° C. and pull off the contact between the conductive carbon materials dispersed in the conductive layer. It is not particularly limited. Examples of the olefin component of the polyolefin resin include ethylene, propylene, isobutylene, isobutene, 1-butene, 2-butene, 1-pentene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-hexene, 1-octene, norbornene, etc. are mentioned. A polymer of a single olefin component may be used, or a copolymer of two or more components may be used.

  As the water-dispersed olefin resin fine particles, the olefin resin is preferably modified with a carboxylic acid or a carboxylic acid ester. Since the melting resistance of the resin can be imparted by the modification, the volume expansion of the polyolefin resin can be maintained when the internal temperature of the electric storage device rises due to an internal short circuit or the like, and the cutting effect of the carbon materials can be maintained. Conceivable. Furthermore, the water-dispersed olefin resin fine particles form an aggregation structure with the conductive carbon material (A) through the multivalent cationic compound (C), and the carbon materials It is thought that the cutting effect of can be further enhanced.

  The component of carboxylic acid or carboxylic ester is not particularly limited, but acrylic acid, methacrylic acid, maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, fumaric acid, crotonic acid, methyl acrylate, (meth) acrylic acid Methyl, ethyl (meth) acrylate, propyl (meth) acrylate, butyl acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, (meth) D) dodecyl acrylate, stearyl (meth) acrylate, vinyl formate, vinyl acetate, vinyl propionate, vinyl piperylate and the like.

As the modification amount of the polyolefin resin fine particles modified above, the resin obtained by removing the dispersion medium from the water-dispersed olefin-based resin fine particles is total by a Fourier transform infrared spectrometer (FT-IR: Spectrum One / 100 manufactured by PerkinElmer) It can be determined by reflectometry (ATR), and is the maximum peak height (maximum absorbance) derived from an olefin of 2800 to 3000 cm ⁻¹ and the maximum peak height (maximum absorbance) derived from a carbonyl of 1690 to 1740 cm ⁻¹ It can be determined from the ratio.

The peak height referred to herein is a solid obtained by removing the dispersion medium from the water-dispersed olefin resin fine particles (B) and finally drying it at 120 ° C. and measuring the solid obtained by FT-IR. The modification amount of the polyolefin resin fine particles was determined by using a spectrum obtained by plotting the absorbance against wave number, and setting a line connecting two points of a point showing the absorbance at 2700 m ^-1 and a point showing the absorbance at 3000 cm ^-1 as the baseline BX. At the time, the height (maximum absorbance) from the maximum peak to the baseline BX (maximum absorbance) (X) and the absorbance at 1650 m ⁻¹ among two or four of the olefin derived from 2800 to 3000 cm ⁻¹ 1850cm when a straight line connecting the two points and the point indicating the absorbance was baseline bY at ^-1, from the maximum peak of the carbonyl derived 1690～1740Cm ^-1 until the baseline bY height (maximum absorbance) (Y) The peak ratio (Y) / (X) of

  The amount of modification of the resin fine particles is preferably such that the peak ratio (Y) / (X) is 0.05 to 1.0.

  The average particle diameter of the water-dispersed olefin resin fine particles (B) used in the present invention is preferably 0.05 to 1 μm from the viewpoint of productivity, stability of the water-dispersed olefin resin fine particles, and internal resistance of the electricity storage device. More preferably, it is 0.05-0.5 micrometer.

  In addition, the average particle diameter in this invention represents the volume average particle diameter (MV), and can be measured by a dynamic light scattering method. The measurement of the average particle size by the dynamic light scattering method can be performed as follows. The water-dispersed olefin resin fine particle dispersion is diluted with water to 200 to 1000 times in accordance with the solid content. About 5 ml of the diluted solution is injected into the cell of a measuring apparatus [Nanotrac manufactured by Nikkiso Co., Ltd.], and the solvent (water in the present invention) according to the sample and the refractive index conditions of the resin are input, and measurement is performed.

  The water-dispersible olefin resin fine particles (B) used in the present invention is preferably anionic in view of the bonding property with the multivalent cationic compound (C). The term "anionic" as used herein means that the resin fine particles have a negative zeta potential in water.

  The zeta potential of the water-dispersed olefin resin fine particles (B) is preferably -5 mV or less, more preferably -10 mV or less, from the viewpoint of bonding with the multivalent cationic compound (C).

  In order for the olefin resin fine particles to exhibit a negative zeta potential, they can be obtained by modification with a carboxylic acid, a carboxylic ester, etc., or by conjugation with an anionic molecule, a resin, a surfactant, etc. It is not something to be done.

  A commercially available product can be used as the water-dispersed olefin resin fine particle as described above, and as a commercially available product, Arrowbase SB-1200, SD-1200, SE-1200, TC-4010, TD-4010 manufactured by Unitika Co., Ltd. can be used. Chemipearl S100, S200, S300, V100, V200, V300, W100, W200, W300, W400, and the like manufactured by Sumitomo Chemical Co., Ltd., Zyxen AC, A, AC-HW-10, L, NC, N, etc. W 4005, WP 100, Hardened NZ-1004 manufactured by Toyobo Co., Ltd., NZ-1015 manufactured by Toho Chemical Co., Ltd., Hitech S-3121 manufactured by Toho Chemical Co., Ltd., etc. may be mentioned, but the invention is not limited thereto. .

  Water is preferably used as the dispersion medium for the water-dispersed olefin resin fine particles (B) used in the present invention, but a liquid medium compatible with water is used for stabilization of the resin fine particles, etc. Also good. As a liquid medium compatible with water, alcohols, glycols, cellosolves, amino alcohols, amines, ketones, carboxylic acid amides, phosphoric acid amides, sulfoxides, carboxylic acid esters, phosphoric acid esters And ethers, nitriles, etc., and may be used in the range compatible with water.

<Multivalent cationic compound (C)>
The multivalent cationic compound (C) in the present invention is cationic in water, and has bivalent or higher cationicity in units of atoms, molecules and particles. For example, monomers, polymers, microparticles, and the like that are water-soluble and divalent or higher cationic metal ions, and that contain two or more cationic functional groups in the molecule, etc. may be mentioned.

  In the present invention, the cationic compound (C) is a water-soluble polyvalent metal compound or positive zeta potential from the viewpoint of bonding with the conductive carbon material (A) and the water-dispersed olefin resin fine particles (B). It is preferable that it is a water-dispersed fine particle showing the

  The polyvalent metal compound of the cationic compound (C) is a metal compound which becomes a divalent or higher metal ion in an aqueous solution.

Examples of water-soluble polyvalent metal compounds include cationic metal ions Ba ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ni ²⁺ , Zn ²⁺ , Cu ²⁺ , Fe ²⁺ , Co ^2+. , Sn ²⁺ , Mn ²⁺ , Al ³⁺ , Fe ³⁺ , Cu ³⁺ , Cr ³⁺ , Sn ⁴⁺ , hydroxide ion (OH ⁻ ) which is an anionic ion, carbonate ion (CO ₃ ^{2 2 −} ), Nitrate ion (NO ₃ ⁻ ), nitrite ion (NO ₂ ⁻ ), sulfate ion (SO ₄ ²⁻ ), phosphate ion (PO ₄ ³⁻ ), hydrogen phosphate ion (HPO ₄ ²⁻ ), acetate ion ^{_{(C 2 H 3 O 2 -}} ), cyanide ion (CN ^-), thiocyanate ion (SCN ₂ ^-), fluoride ion (F ^-), hexafluorosilicic acid ions _(SiF ^{6 2-),} chlorides ion (Cl ^-), chlorate ion _(ClO ³ -), Chlorate ion (ClO ₂ ^-), perchlorate ion (ClO ^-), bromide ion (Br ^-), bromate ion (BrO ₃ ^-), permanganate ion (MnO ₄ ^-), chromate ion (CrO ₄ ^2- ), formate ion (HCO ₂ ⁻ ), benzoate ion (C ₇ H ₅ O ₂ ⁻ ), oxalate ion (C ₂ O ₄ ^{2 −} ), tartrate ion (C ₄ H ₄ O ₆ ²⁻ ) Although the compound etc. which consist of a combination of, etc. are mentioned, it is not limited to these, You may use combining two or more types of compounds.

  As the water-soluble polyvalent metal, preferably a divalent, trivalent or tetravalent metal ion is preferably used, more preferably a divalent or trivalent metal ion is used, and a divalent metal ion is preferably used. It is more preferable to use. By using divalent metal ions, it is considered that the effect of volume expansion with respect to the addition amount of the olefin-based resin fine particles is further enhanced because bead-like aggregated particles are formed.

  It is particularly preferable to use a magnesium or calcium compound from the viewpoint of availability and storage device performance.

  Examples of the water-dispersible fine particles having a positive zeta potential include fine particles having a cationic functional group and the like, and examples thereof include organic or inorganic fine particles.

  The organic water-dispersible fine particles are, for example, vinyl resins such as polyacrylate and polystyrene, and those obtained by introducing cationic functional groups into resin fine particles such as polyurethane, polyester and polyepoxy. As the functional group, for example, a reaction product with primary to tertiary amino group, phosphine group hydrochloric acid, nitric acid, acetic acid, sulfuric acid, sulfuric acid, propionic acid, butyric acid, (meth) acrylic acid, maleic acid and the like And quaternary ammonium groups, quaternary phosphonium groups, etc., but it is not limited thereto.

Examples of the inorganic water-dispersible fine particles include fine particles of alumina, titania, ceria and the like, silica surface-modified with alumina and the like, but are not limited thereto.

  The water-dispersed fine particles exhibiting a positive zeta potential are dispersed in an aqueous medium, and the average particle diameter of the dispersed particles is preferably 0.005 to 1 μm from the viewpoint of dispersibility and bondability. Preferably it is 0.01-0.05 micrometer.

  The zeta potential of the water-dispersed fine particles exhibiting a positive zeta potential is preferably +5 mV or more, and more preferably from the viewpoint of bonding with the conductive carbon material (A) or the water-dispersed olefin resin fine particles (B). It is +10 mV or more.

<Aqueous liquid medium (D)>
As the aqueous liquid medium (D) used in the present invention, water is preferably used, but if necessary, for example, a liquid medium compatible with water to improve the coatability on the current collector. You may use

  As a liquid medium compatible with water, alcohols, glycols, cellosolves, amino alcohols, amines, ketones, carboxylic acid amides, phosphoric acid amides, sulfoxides, carboxylic acid esters, phosphoric acid esters And ethers, nitriles, etc., and may be used in the range compatible with water.

  Further, a surfactant, a film forming aid, an antifoaming agent, a leveling agent, a preservative, a pH adjuster, a viscosity adjuster, and the like can be added to the conductive composition as required.

  The surfactant used in the present invention is not particularly limited as long as it can disperse the conductive carbon material. For example, as the nonionic surfactant, an ester type such as glycerin fatty acid ester, polyoxy Ether type such as ethylene alkyl phenyl ether may be mentioned, and as an ionic surfactant, monoalkyl sulfate of an anionic surfactant, alkyl benzene sulfonate, etc., as a cationic surfactant, dialkyl dimethyl ammonium Although a salt, an alkyl benzyl dimethyl ammonium salt, etc. are mentioned, it is not limited to these, You may use combining 2 or more types.

<Water-soluble resin (E)>
According to the water-soluble resin (E) of the present invention, 1 g of the water-soluble resin (E) is added to 99 g of water at 25 ° C., stirred, and left at 25 ° C. for 24 hours. It is dissolvable.

  The water-soluble resin (E) is not particularly limited as long as it is a resin exhibiting water solubility as described above, but, for example, acrylic resin, polyurethane resin, polyester resin, polyamide resin, polyimide resin, polyallylamine resin, The high molecular compound containing resin of polysaccharides, such as a phenol resin, an epoxy resin, a phenoxy resin, a urea resin, a melamine resin, an alkyd resin, a formaldehyde resin, a silicone resin, a fluorine resin, carboxymethylcellulose, is mentioned. In addition, as long as it is water soluble, modified products, mixtures or copolymers of these resins may be used. These water-soluble resins can be used alone or in combination of two or more.

  The molecular weight of the water-soluble resin (E) is not particularly limited, but preferably the mass average molecular weight is 5,000 to 2,000,000. Mass average molecular weight (Mw) shows the polyethylene oxide conversion molecular weight in gel permeation chromatography (GPC).

<Other additives>
Furthermore, to the conductive composition, a surfactant, a film forming aid, an antifoaming agent, a leveling agent, a preservative, a pH adjusting agent, a viscosity adjusting agent and the like can be added as needed.

<Distributor / mixer>
As an apparatus used when obtaining the conductive composition of the present invention and a mixture ink described later, a disperser or mixer generally used for pigment dispersion can be used.
For example, mixers such as a disper, homomixer, or planetary mixer; homogenizers such as "CLEARMIX" manufactured by M. Tech. Co., or "FILMIX" manufactured by PRIMIX Co., Ltd .; paint conditioners (manufactured by Red Devil Co.), ball mills, sand mills Media type disperser such as (Dyno Mill, manufactured by Shinmaru Enterprises Co., Ltd.), Atelier, Pearl Mill (“DCP Mill”, manufactured by Eirich Co., Ltd.), Co-ball mill, etc .; Wet jet mill (“Jenas PY”, manufactured by Jenas Ltd.) Medialess dispersing machines such as "Starburst" manufactured by Machine, "Nanomizer" manufactured by Nanomizer, etc., "Clare SS-5" manufactured by M. Tech., Or "MICROS" manufactured by Nara Machinery; or other roll mills etc. But The present invention is not limited to these. Moreover, as a disperser, it is preferable to use what performed the metal mixing prevention process from a disperser.

  For example, when using a media type dispersing machine, a method in which an agitator and a vessel use a ceramic or resin dispersing machine, or a dispersing machine in which the surface of a metal agitator and vessel is treated with tungsten carbide spraying or resin coating. It is preferable to use And, as media, it is preferable to use glass beads or ceramic beads such as zirconia beads or alumina beads. Also when using a roll mill, it is preferable to use a ceramic roll. Only one type of dispersing device may be used, or a plurality of types of devices may be used in combination. In addition, in the case of a positive or negative electrode active material in which particles are easily broken or crushed by a strong impact, a medialess dispersing machine such as a roll mill or a homogenizer is preferable to a media type dispersing machine.

  The conductive composition of the present invention can disperse the conductive carbon material (A) by applying the appropriate shear or impact by the above-mentioned disperser or the like to produce a conductive composition. If shearing or impact is not applied, the conductive carbon materials aggregate due to the cationic compound (C), and the conductive carbon materials can be cut due to volume expansion of the water-dispersed olefin resin fine particles (B). It disappears. On the other hand, if excessive shear or impact is applied, the conductive carbon material may be broken, and the internal resistance of the battery during normal operation or the internal resistance when the internal temperature of the battery rises may not be sufficiently increased.

<Glossy value of coating film>
The degree of dispersion of the carbon material of the conductive composition can be evaluated by the gloss of the coating film, and as the aggregates of the carbon materials become smaller, the gloss value of the coating film becomes larger. The coating obtained by applying and drying the conductive composition on a PET (polyethylene terephthalate) film can be measured by a gloss meter (60 °). Specifically, the gloss value of the coating of the conductive composition is preferably 1 to 10, and more preferably 2 to 5. If the gloss value is low, the carbon compounds can not be cut by the cationic compound (C). If the gloss value is high, the formation of the conductive path becomes insufficient and the internal resistance of the battery may increase during normal use. is there.

  In the present invention, the gloss value of the coating of the conductive composition can be measured as follows. The produced conductive composition is coated on a PET film so as to have a film thickness of about 3 μm, and then put in an oven at 150 ° for 2 to 5 minutes to prepare a coating. This coating is placed on a black flat plate and measured with a gloss meter (micro-TRI-gloss manufactured by BYK). In the present invention, a value of 60 ° is read and taken as the gloss value. Although it is preferable to measure what was coated on PET film in the measurement of the gloss of a coating film, you may measure what was coated to Al foil etc.

<Coated collector with base layer for storage device, electrode for storage device>
The current collector with an underlayer for an electricity storage device of the present invention is one having an underlayer formed from the conductive composition of the present invention on the current collector.
In addition, the electrode for a storage battery device of the present invention refers to a composition for forming an electrode (mixture material) containing a base layer formed of the conductive composition of the present invention, an electrode active material and a binder on a current collector. And a mixture layer formed from the ink).

<Current collector>
The material and shape of the current collector used for the electrode are not particularly limited, and materials suitable for various power storage devices can be appropriately selected. For example, as a material of the current collector, a metal or alloy such as aluminum, copper, nickel, titanium, or stainless steel can be mentioned. In the case of a lithium ion battery, in particular, aluminum is preferable as a positive electrode material and copper is preferable as a negative electrode material. In general, a flat plate foil is used as the shape, but it is also possible to use a roughened surface, a perforated foil, or a mesh current collector.

<Underlayer>
The conductive composition for base layer formation of the electrode for a storage battery device of the present invention can be coated and dried on a current collector to form a base layer.
There is no restriction | limiting in particular as a method of coating a conductive composition and the mixture ink mentioned later on a collector, A well-known method can be used. Specifically, die coating method, dip coating method, roll coating method, doctor coating method, knife coating method, spray coating method, gravure coating method, screen printing method or electrostatic coating method can be mentioned, and drying is possible. As the method, although it is possible to use standing drying, a blast dryer, a hot air dryer, an infrared heater, a far infrared heater, etc., it is not particularly limited thereto, and after coating, it is subjected to a rolling treatment by a lithographic press, a calender roll, etc. You may

  The thickness of the underlayer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and still more preferably 0.5 from the viewpoint of the energy density of the storage device and the increase in resistance when the storage device generates heat. ~ 3 μm.

Ingredients ink
The composite ink refers to a liquid or paste in which an active material which is a component of an electrode used in an electricity storage device, a binder, a solvent, and the like is in the form of liquid or paste, and in the electrode for electricity storage device of the present invention, The active material and the solvent are essential, and if necessary, a conductive auxiliary and a binder are contained.
The active material is preferably contained as much as possible. For example, the ratio of the active material to the solid content of the ink mixture is preferably 80 to 99% by mass. When it contains a conductive support agent, it is preferable that the ratio of the conductive support agent to the mixture ink solid content is 0.1 to 15% by mass. When it contains a binder, it is preferable that the ratio of the binder which occupies for mixture ink solid content is 0.1-15 mass%.

  Although depending on the coating method, the viscosity of the composite ink is preferably 100 mPa · s or more and 30,000 mPa · s or less in the range of solid content of 30 to 90% by mass.

  Although the solvent (dispersion medium) of the composite ink is not particularly limited, it can be used properly depending on the binder to be used. For example, when using a resin type binder, a solvent capable of dissolving the resin is used, and when using an emulsion type binder, it is preferable to use a solvent capable of maintaining the dispersion of the emulsion. As the solvent, for example, amides such as dimethylformamide, dimethylacetamide and methylformamide, amines such as N-methyl-2-pyrrolidone (NMP) and dimethylamine, ketones such as methyl ethyl ketone, acetone and cyclohexanone, alcohols Examples include glycols, cellosolves, aminoalcohols, sulfoxides, carboxylic acid esters, phosphoric acid esters, ethers, nitriles, water and the like. Moreover, you may use it, combining 2 or more types of the said solvent as needed. For example, when polyvinylidene fluoride (PVDF) is used as a binder, NMP capable of dissolving PVDF is preferably used, and when carboxymethylcellulose (CMC) and styrene butadiene rubber (SBR) are used as a binder, CMC is dissolved to Water capable of maintaining dispersion is preferably used.

  The active material used in the composite ink will be described below.

  The positive electrode active material for lithium ion secondary batteries is not particularly limited, but metal oxides such as metal oxides which can be doped or intercalated with lithium ions, metal compounds such as metal sulfides, and conductive polymers are used. be able to.

For example, oxides of transition metals such as Fe, Co, Ni, and Mn, composite oxides with lithium, inorganic compounds such as transition metal sulfides, and the like can be mentioned. Specifically, transition metal oxide powder such as MnO, V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , lithium nickelate having a layered structure, lithium cobaltate, lithium manganate, lithium manganate having a spinel structure, etc. Composite oxide powder of lithium and transition metal, lithium iron phosphate material which is a phosphate compound having an olivine structure, transition metal sulfide powder such as TiS ₂ , FeS, and the like can be mentioned.

  In addition, conductive polymers such as polyaniline, polyacetylene, polypyrrole and polythiophene can also be used. In addition, the above-mentioned inorganic compounds and conductive polymers may be mixed and used.

  The negative electrode active material for a lithium ion secondary battery is not particularly limited as long as it can be doped or intercalated with lithium ions. For example, metallic lithium, alloys thereof such as tin alloys, silicon alloys, alloys of lead alloys, etc., lithium titanate, metallic oxides such as lithium vanadate, lithium siliconate, etc., conductive such as polyacetylene, poly-p-phenylene, etc. Polymers, amorphous carbon materials such as soft carbon and hard carbon, artificial graphite such as highly graphitized carbon materials, carbon powders such as natural graphite, carbon black, mesophase carbon black, resin fired carbon materials, Carbon-based materials such as air-grown carbon fibers and carbon fibers can be mentioned. These negative electrode active materials can be used alone or in combination of two or more.

Although it does not specifically limit as an electrode active material for electric double layer capacitors, Activated carbon, polyacene, carbon whisker, a graphite, etc. are mentioned, These powders or fibers etc. are mentioned. Preferred electrode active materials for electric double layer capacitors are activated carbons, specifically activated carbons activated with phenol, coconut shell type, rayon type, acrylic type, coal / petroleum based pitch coke, meso carbon micro beads (MCMB), etc. Can be mentioned. It is preferable to use one having a large specific surface area capable of forming an interface of the same mass and a larger area. Specifically, the specific surface area of ^{30 m} 2 / g or more, preferably preferably 500~5000m ² / g, more preferably 1000~ 3000m ² / g.

  You may use these electrode active materials individually or in combination of 2 or more types.

  The positive electrode active material for a lithium ion capacitor is not particularly limited as long as it is a material capable of reversibly doping and dedoping lithium ions and anions, and examples thereof include activated carbon powder.

  The negative electrode active material for lithium ion capacitors is not particularly limited as long as it is a material capable of reversibly doping and dedoping lithium ions, and, for example, graphite-based materials such as artificial graphite and natural graphite It can be mentioned.

  The conductive auxiliary agent in the composite ink is not particularly limited as long as it is a carbon material having conductivity, and the same conductive carbon material (A) as described above can also be used.

  The binder in the composite ink is used to bind particles of an active material or a conductive carbon material to each other, or to bind a conductive carbon material and a current collector.

As a binder used in the composite ink, for example, acrylic resin, polyurethane resin, polyester resin, phenol resin, epoxy resin, phenoxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, formaldehyde resin, silicone resin, fluorine resin, Cellulose resins such as carboxymethyl cellulose, synthetic rubbers such as styrene-butadiene rubber and fluorine rubber, conductive resins such as polyaniline and polyacetylene, etc., and high-molecular compounds containing fluorine atoms such as polyvinylidene fluoride, polyvinyl fluoride, and tetrafluoroethylene Can be mentioned. In addition, modified products, mixtures or copolymers of these resins may be used. These binders may be used alone or in combination of two or more.
Moreover, as a binder suitably used in aqueous | water-based composite material ink, the thing of a water medium is preferable, As a form of the binder of a water medium, a water-soluble type, an emulsion type, a hydrosol type etc. are mentioned, It selects suitably. be able to.

  Furthermore, a film forming aid, an antifoaming agent, a leveling agent, an antiseptic, a pH adjuster, a viscosity adjuster, and the like can be added to the mixture ink as necessary.

<Method of manufacturing electrode>
The conductive composition of the present invention can be coated and dried on a current collector to form an underlayer, whereby an underlayer electrode for a storage battery device can be obtained.

  Alternatively, the conductive composition of the present invention may be coated and dried on a current collector to form a base layer, and a mixture layer may be provided on the base layer to obtain an electrode for a storage battery device. The mixture layer provided on the base layer can be formed using the above-described mixture ink.

<Storage device>
By using the above electrode as at least one of the positive electrode and the negative electrode, a storage device such as a secondary battery or a capacitor can be obtained.

  Examples of secondary batteries include lithium ion secondary batteries, sodium ion secondary batteries, magnesium ion secondary batteries, alkaline secondary batteries, lead storage batteries, sodium sulfur secondary batteries, lithium air secondary batteries, etc. An electrolyte solution, a separator, etc. conventionally known for each secondary battery can be used appropriately.

  As a capacitor, an electric double layer capacitor, a lithium ion capacitor, etc. are mentioned, The electrolyte solution, the separator, etc. which are conventionally known by each capacitor can be used suitably.

<Electrolyte solution of non-aqueous electrolyte>
The case of a lithium ion secondary battery will be described as an example. As the electrolytic solution, one in which an electrolyte containing lithium is dissolved in a non-aqueous solvent is used.

As the electrolyte, LiBF ₄ , LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , 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, or LiBPh ₄ (wherein Ph represents a phenyl group) and the like, but not limited thereto.

The non-aqueous solvent is not particularly limited, and for example, carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate;
lactones such as γ-butyrolactone, γ-valerolactone, and γ-octanoic lactone;
Glymes such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,2-methoxyethane, 1,2-ethoxyethane, and 1,2-dibutoxyethane;
Esters such as methyl formate, methyl acetate and methyl propionate; sulfoxides such as dimethyl sulfoxide and sulfolane; and
Nitriles such as acetonitrile and the like can be mentioned. These solvents may be used alone or in combination of two or more.

  Furthermore, the above-mentioned electrolytic solution can be held in a polymer matrix to form a gel-like polymer electrolyte. Examples of the polymer matrix include, but are not limited to, acrylate resins having a polyalkylene oxide segment, polyphosphazene resins having a polyalkylene oxide segment, and polysiloxanes having a polyalkylene oxide segment.

<Separator>
Examples of the separator include, but are not particularly limited to, polyethylene non-woven fabric, polypropylene non-woven fabric, polyamide non-woven fabric and those obtained by subjecting them to hydrophilic treatment.

  The structure of a lithium ion secondary battery, an electric double layer capacitor, and a lithium ion capacitor using the conductive composition of the present invention is not particularly limited, but usually, it comprises a positive electrode and a negative electrode, and a separator provided as needed. It can be made into various shapes according to the purpose of use, such as a paper type, a cylinder type, a button type, and a lamination type.

<Conductive composition>
Example 1
Calcium nitrate as polycationic compound (C) tetrahydrate _{(C-1: Ca (NO} 3) 2 · 4H 2 O) to dissolve put deionized water, and 10 wt% as the calcium (Ca) The aqueous solution was adjusted.
As a conductive carbon material, 1000 parts by mass of ion-exchanged water as an aqueous liquid medium (D) and 50 parts by mass of acetylene black (A-1) and a non-ionic surfactant of ether type (Triton X: Roche Life Science Co., Ltd.) Ltd.) 0.4 part by mass placed in a mixer and after adding 1 part by weight of the 10 wt% aqueous solution of calcium, further placed in a sand _mill, it was dispersed until a gloss value of 5.
Next, 166.7 parts by mass of water-dispersed olefin resin fine particles (B-1: 30% by mass) were added and mixed by a mixer to obtain a conductive composition (1).

The materials and conductive compositions used in the examples and comparative examples were evaluated as follows.
(Average particle size (MW) of water-dispersed olefin resin fine particles and cationic water-dispersed particles)
The water-dispersed olefin-based resin fine particles or the cationic water-dispersed particles are diluted with water to 200 to 1000 times depending on the solid content and the like, and 5 ml of the diluted solution is injected into the cell of Nanotrac (Wave-EX 150 manufactured by Nikkiso Co., Ltd.) After inputting the dispersion medium (water in the present invention) and the refractive index conditions of the resin and particles according to the sample, measurement was performed to determine the average particle size (MW).

(Modified amount of olefin resin fine particles (Y) / (X))
The water-dispersed olefin resin fine particles (B) were placed in an oven at 80 ° C. to remove the dispersion medium, and then dried at 120 ° C. for 30 minutes to obtain a solid. This was measured by total reflection measurement (ATR) with a Fourier transform infrared spectrometer (FT-IR: Spectrum One / 100 manufactured by PerkinElmer).
Modification amount using spectral plotting absorbance against wave numbers, when used as a baseline BX a straight line connecting two points of the point indicating the absorbance at a point and 3000 cm ^-1 indicating the absorbance at 2700 cm ^-1, 2800 Connect the two points from the maximum peak from olefin to 3000 cm ^-1 to the baseline BX (maximum absorbance) (X) and the point showing the absorbance at 1650 m ^-1 and the point showing the absorbance at 1850 cm ^-1 The ratio (Y) / (X) to the height (maximum absorbance) (Y) from the carbonyl-derived maximum peak of 1690 to 1740 cm ⁻¹ when the straight line was taken as the baseline BY was determined.

(Zeta potential of water-dispersed olefin resin fine particles and cationic water-dispersed particles)
20 ml of the dispersion obtained by diluting the water-dispersed olefin resin and the cationic water-dispersed particles with water if necessary is injected into the cell of the zeta potential measurement device (ZetaProbe manufactured by Colloidal Dynamics), and the dispersion medium according to the sample (this In the invention, after inputting the refractive index conditions of water and particles, measurement is performed to determine the zeta potential.
(Glossy value of conductive composition)
The prepared conductive composition is coated on a PET (polyethylene terephthalate) film so that the film thickness is about 3 μm, and then placed in an oven at 150 ° C. for 2 to 5 minutes to remove the aqueous liquid medium and coat Made. The coated film was placed on a black flat plate, and the value of 60 ° was read with a gloss meter (micro-TRI-gloss manufactured by BYK).

(Examples 2 to 13)
The conductive compositions (2 of the examples) were prepared in the same manner as the conductive composition (1) except that the dispersion time of the sand mill was changed so as to obtain the composition ratios shown in Table 1 and the gloss values shown in Table 1. ) To (13).

(Example 14)
As a conductive carbon material, 25 parts by mass of acetylene black (A-1), 1000 parts by mass of a 2.5 mass% aqueous solution of carboxymethyl cellulose (E-1) which is a water-soluble resin (25 parts by mass as solid content) Put in and mix. Subsequently, 1 part by mass of the 10% by mass calcium aqueous solution used in Example 1 was added, and then the resultant was further placed in a sand mill to perform dispersion.
Next, 166.7 parts by mass of water-dispersed olefin resin fine particles (B-1: 30% by mass) were added, and mixed by a mixer to obtain a conductive composition (14).
(Example 15 and Example 16)
Conductive compositions (15) and (16) of Examples were obtained by the same method as the conductive composition (14), respectively, except that the compositional ratio shown in Table 1 was changed.

(Comparative example 1)
A conductive composition (17) was obtained with the composition shown in Table 1 by the same method as in Example 1 except that the multivalent cationic compound (C) was not added.
(Comparative Examples 2 and 3)
Conductive compositions (18) and (19) were obtained with the compositions shown in Table 1 by the same method as Example 1, except that the dispersion time of the sand mill was changed so as to obtain the gloss values shown in Table 1.
(Comparative example 4)
An aqueous solution of 10% by mass sodium chloride (NaCl) is added instead of the polyvalent cationic compound, and the addition amount of sodium ions is 0.1% by mass based on the total solid content of the conductive composition. A conductive composition (20) was obtained with the composition shown in Table 1 by the same method as in Example 1.
(Comparative example 5)
A silica aqueous dispersion (solid content 20 mass%, volume average particle size (MW) 0.01 μm, zeta potential-50 mV) is added instead of the polyvalent cationic compound, and the addition amount of silica is the total solid of the conductive composition A conductive composition (21) was obtained with the composition shown in Table 1 by the same method as in Example 1 except that 0.1% by mass with respect to the amount was added.
(Comparative example 6)
A conductive composition (22) was obtained with the composition shown in Table 1 by the same method as in Example 1 except that the addition amount of the polyvalent cationic compound was changed.

The materials used in Examples and Comparative Examples are shown below.
(Conductive carbon material (A))
A-1: Denka Black HS-100 (made by Denka Co., Ltd.)
A-2: Ketjen Black EC-300J (manufactured by Lion Corporation)
(Water-dispersed olefin resin fine particles (B))
· B-1: solid content 30 mass% aqueous dispersion, volume average particle size (MW) 0.2 μm, carboxylic acid ester modification, modification amount (Y) / (X) 0.6, polyethylene, zeta potential-30 mV
· B-2: solid content 30 mass% aqueous dispersion, volume average particle size (MW) 0.2 μm, carboxylic acid ester modification, modification amount (Y) / (X) 0.18, polypropylene, zeta potential-60 mV
・ B-3: solid content 30 mass% aqueous dispersion, volume average particle diameter (MW) 0.2 μm, carboxylic acid ester modification, modification amount (Y) / (X) 0.13, polyethylene, zeta potential -10 mV
(Polyvalent cationic compound (C))
C-1: Calcium nitrate tetrahydrate (Ca (NO ₃ ) _2. 4 H ₂ O, divalent metal ion compound)
· C-2: Magnesium nitrate hexahydrate _{(Mg (NO 3) 2 ·} 6H 2 O, 2 -valent metal ion compound)
C-3: Alumina surface-modified silica aqueous dispersion, solid content 20% by mass, volume average particle size (MW) 0.01 μm, zeta potential + 50 mV
The water-soluble metal compound was dissolved by adding ion-exchanged water to a metal ion concentration of 10% by mass, and the respective aqueous solutions were adjusted and used.
(Water-soluble resin (E))
E-1: CMC Daicel # 1240 (manufactured by Daicel Chemical Industries, Ltd.)
E-2: Sodium polyacrylate, average molecular weight 10000 (manufactured by Wako Pure Chemical Industries, Ltd.)
E-3: Kuraray Poval PVA 235 (manufactured by Kuraray)

The obtained conductive composition is shown in Table 1.

<Coated collector with underlayer>
The conductive compositions (1) to (22) are coated on a 20 μm thick aluminum foil as a current collector using a bar coater, and then dried by heating at 80 ° C. to a thickness of 2 μm. Underlayer-provided current collectors (1) to (22) for a non-aqueous electrolyte secondary battery were obtained.

<Mixing material ink for lithium ion secondary battery positive electrode>
93 parts by mass of LiNi _0.5 Mn _0.3 Co _0.2 O ₂ as a positive electrode active material, 4 parts by mass of acetylene black (Denka Black HS-100, manufactured by Denka Co., Ltd.) as a conductive agent, polyvinylidene fluoride (KF polymer as a binder 3 parts by mass of # 1300 (manufactured by Kureha Co., Ltd.) and 45 parts by mass of N-methylpyrrolidone were added and mixed to prepare an ink for a positive electrode.

<Compatible ink for lithium ion secondary battery negative electrode>
98 parts by mass of artificial graphite as a negative electrode active material, 66.7 parts by mass of carboxymethyl cellulose (CMC Daicel # 1190, made by Daicel Chemical Industries, Ltd.) 1.5% aqueous solution (1 part by mass as solid content) are mixed in a planetary mixer And 33 parts by mass of water and 2.08 parts by mass of a 48% by mass aqueous dispersion of styrene butadiene emulsion (TRD 2001, manufactured by JSR Corporation) (1 part by mass as solid content) are mixed to prepare a mixture ink for secondary battery negative electrode. Obtained.

<Positive electrode for lithium ion secondary battery with underlayer>
After applying the above-mentioned lithium ion secondary battery positive electrode mixture material ink to a current collector ((1) to (22) with an underlayer for a secondary battery using a doctor blade, heat drying is performed at 80 ° C. The weight per unit area of the electrode was adjusted so as to be 20 mg / cm ^2. Further, the rolling process was performed by a roll press, and the density of the material layer was 3.1 g / cm ^3. ) To (22) were produced.

<Anode for lithium ion secondary battery>
The above-described ink for a lithium ion secondary battery negative electrode mixture is coated on a copper foil having a thickness of 20 μm as a current collector using a doctor blade, and then heat dried at 80 ° C. to coat the electrode per unit area The amount was adjusted to 12 mg / cm ² . Furthermore, the rolling process by roll press was performed, and the density of the composite material layer produced the negative electrode used as 1.5 g / cm < ³ >.

<Laminated lithium ion secondary battery>
The positive and negative electrodes shown in Table 2 are punched into 45 mm × 40 mm and 50 mm × 45 mm, respectively, and the separator (porous polypropylene film) inserted between them is inserted into an aluminum laminate bag and vacuum dried and then electrolytic solution (A non-aqueous electrolytic solution in which LiPF ₆ is dissolved at a concentration of 1 M) is injected into a mixed solvent in which ethylene carbonate and diethyl carbonate are mixed at a ratio of 1: 1 (volume ratio), and then the aluminum laminate is sealed. A laminate type lithium ion battery was produced. The production of the laminate type lithium ion battery is carried out in an argon gas substituted glove box, and after the production of the laminate type lithium ion battery, the battery characteristics of initial resistance, increase in resistance, rate characteristics and cycle characteristics shown below are evaluated. The

(Resistance measurement)
Resistance measurement was performed at 25 ° C. while applying a load of 10 kPa to the laminated type battery which was subjected to constant current discharge at a discharge termination voltage of 3.0 V at a discharge current of 12 mA (0.2 C). The cell was then heated and resistance measurements were taken when the surface temperature reached 180 ° C. Resistance measurement was performed at 500 kHz with an impedance analyzer (SP-50 manufactured by biologic).
The resistance measured at 25 ° C. was taken as the initial resistance, and the quotient of the resistance measured at 180 ° C. and the resistance measured at 25 ° C. was taken as the resistance increase. That is, the increase in resistance is represented by the following (Expression 1).
(Expression 1) Resistance increase = resistance value at 180 ° C./resistance initial value at 25 ° C. The results obtained by evaluating the resistance and the resistance increase based on the following criteria are shown in Table 2.
· Initial resistance :: "The initial resistance is smaller than the initial resistance without the underlayer (Al foil only). Excellent."
Δ: “The initial resistance is slightly smaller than the initial resistance without the underlayer (Al foil only). A practicable level.”
Δ ×: “The initial resistance is equal to the initial resistance without the underlayer (Al foil only). A level that needs improvement.”
X: "The initial resistance is larger than the initial resistance without the underlayer (Al foil only). It is inferior."
・ Resistance increase ◎: “The resistance increase is 10 times or more of the initial resistance. It is particularly excellent.”
:: “The increase in resistance is at least 5 times and less than 10 times the initial resistance. It is excellent.”
Δ: “The increase in resistance is more than 3 times and less than 5 times the initial resistance. The effect is not sufficient but it can be used.”
Δ ×: “The increase in resistance is more than twice and less than three times the initial resistance. The level that needs improvement”
X: "The increase in resistance is less than twice the initial resistance. This is the same level as without the base layer (Al foil only)."

(Rate characteristic)
The charge and discharge measurement was performed using the charge and discharge device (SM-8 manufactured by Hokuto Denko Co., Ltd.) for the laminated battery described above.
Charge current 12 mA (0.2 C), charge termination voltage 4.2 V, constant current constant voltage charge (cut-off current 0.6 mA, then discharge current 12 mA (0.2 C) and 120 mA (2 C) discharge termination The discharge capacity was determined by performing constant current discharge until the voltage reached 3.0 V. The rate characteristics were represented by the ratio of the 0.2 C discharge capacity to the 2 C discharge capacity, that is, the following (Equation 2).
(Expression 2) Rate characteristic = 2 C discharge capacity / 0.2 C discharge capacity × 100 (%)
The results evaluated based on the following criteria are shown in Table 2.
・ Rate characteristic ○: “The rate characteristic is 80% or more. Especially excellent.”
Δ: “Rate characteristic is 75% or more and less than 80%. Excellent”
Δ ×: “Rate characteristic is 70 or more and less than 75%. Equivalent to that of no underlayer (Al foil only)”
X: "The rate characteristic is less than 70%. It is inferior."

(Cycle characteristics)
After performing constant current constant voltage charging (cut-off current 0.6 mA) with a charge termination voltage of 60 mA and a charge termination voltage of 4.2 V in a 50 ° C. constant temperature bath, the discharge termination voltage reaches 3.0 V with a discharge current of 60 mA The constant current discharge was performed until the first discharge capacity was determined. The charge and discharge cycle was performed 200 times, and the discharge capacity retention ratio (percentage of the 200th discharge capacity to the first discharge capacity) was calculated. The results evaluated based on the following criteria are shown in Table 2.
Cycle characteristics O: "The discharge capacity retention rate is 90% or more. Especially excellent."
Δ: “Discharge capacity retention rate is 85% or more and less than 90%. Excellent”
Δ ×: “Discharge capacity retention ratio is 80% or more and less than 85%. Equivalent to the discharge capacity retention ratio without base layer (Al foil only).”
X: "The discharge capacity retention rate is less than 80%. It is inferior."

As shown in Table 2, in Comparative Example 1 and Comparative Example 4 and Comparative Example 5 in which the multivalent cationic compound was not contained, no noticeable rise in resistance was confirmed when the internal temperature of the battery increased. As shown in the examples of the invention, the addition of the multivalent cationic compound was confirmed to have the effect of increasing the internal resistance of the battery.
On the other hand, as in Comparative Example 2 and Comparative Example 3, despite the presence of the polyvalent cationic compound, no noticeable increase in resistance was confirmed even when the internal temperature of the battery increased. In Comparative Example 2, since the bond between the conductive carbon materials is strong, the cutting effect is weak, and in Comparative Example 3, since the conductive carbons are dispersed excessively, it is difficult to form the conductive path of the underlayer. The initial resistance is high, and the rate of increase in resistance is considered to be reduced.
In addition, in Comparative Example 6, since the polyvalent cationic compound is added in excess, the bonding between the conductive carbon materials is strengthened, and even if the internal temperature of the battery rises, the carbon materials can not be cut. It is thought that
From the above results, according to the present invention, when the internal resistance of the battery is increased due to the excellent output characteristics of the battery and the internal short circuit or the like, the current flowing to the short circuit portion is suppressed by raising the internal resistance. The present invention can provide a conductive composition for forming a non-aqueous electrolyte secondary battery having a function of enhancing the safety of the battery.
From the above results, according to the present invention, when the internal resistance of the battery is increased due to the excellent output characteristics of the battery and the internal short circuit or the like, the current flowing to the short circuit portion is suppressed by raising the internal resistance. The present invention can provide a conductive composition for forming a non-aqueous electrolyte secondary battery having a function of enhancing the safety of the battery.

<Positive electrode for electric double layer capacitors, composite ink for negative electrode>
85 parts of activated carbon (specific surface area: 1800 m ² / g) as active material, 5 parts of conductive aid (acetylene black: Denka black HS-100, manufactured by Denka), carboxymethylcellulose (CMC Daicel # 1190, manufactured by Daicel Chemical Industries, Ltd.) 8 Parts, binder (Polytetrafluoroethylene 30-J: 60% aqueous dispersion manufactured by DuPont Fluorochemicals, Mitsui, 2 parts as solid content) and 220 parts of water are mixed to combine the positive electrode and the negative electrode Material ink was produced.

<Positive Electrode for Electric Double Layer Capacitor with Base Layer (Example 17, Comparative Example 7)>
The above-mentioned mixture ink for an electric double layer capacitor is coated on the current collector with an underlayer (1) of Example 1 and the current collector with an underlayer of Comparative Example 1 (17) using a doctor blade, After drying by heating at 80 ° C., rolling processing was carried out by a roll press, and positive electrodes (23) and (24) having a thickness of 50 μm were produced.
<Negative electrode for base layer-less electric double layer capacitor>
The above-mentioned mixture ink for an electric double layer capacitor is coated on a 20 μm thick aluminum foil serving as a current collector using a doctor blade, heated and dried, then rolled by a roll press, and the thickness of the electrode is A negative electrode of 50 μm was produced.

<Electric double layer capacitor>
The positive and negative electrodes shown in Table 3 are respectively punched to a diameter of 16 mm, and a separator (porous polypropylene film) inserted between them is made into an electrolyte (propylene carbonate solvent (TEMABF ₄ (boron tetrafluoride triethylmethyl ammonium) 1 M) An electric double layer capacitor was prepared in an argon gas substituted glove box, and the electric double layer capacitor was prepared as follows: Electrical characterization was performed.

(Charge / discharge cycle characteristics)
About the obtained electric double layer capacitor, charging / discharging measurement was performed using the charging / discharging apparatus.

  After charging to a charge termination voltage of 2.0 V at a charge current of 10 C rate, constant current discharge was carried out until a discharge termination voltage of 0 V was reached at a discharge current of 10 C rate. The charge / discharge cycle of these five cycles is repeated with one cycle of these charge / discharge cycles, and the discharge capacity of the fifth cycle is taken as the initial discharge capacity. (The initial discharge capacity is 100% maintenance rate). The charge / discharge current rate was 1 C, which is the magnitude of the current capable of discharging the cell capacity in one hour.

  Next, charging was performed at a charge termination voltage of 2.0 V at a charge current of 10 C rate in a 50 ° C. constant temperature bath, and then constant current discharge was performed at a discharge current of 10 C rate until reaching a discharge termination voltage of 0 V. The charge and discharge cycle was performed 500 times, and the discharge capacity retention ratio (percentage of the 500th discharge capacity to the first discharge capacity) was calculated (the closer to 100%, the better).

:: “Discharge capacity retention rate is 95% or more. Especially excellent.”
△: “Discharge capacity maintenance rate is 90% or more and less than 95%. There is no problem at all.”
Δ: “Discharge capacity retention rate is 85% or more and less than 90%. There is a problem but usable level.”
X: "The discharge capacity retention rate is less than 85%. There is a problem in practical use and can not be used."

(Resistance measurement)
The resistance of the electric double layer capacitor charged at a charge current of 10 C rate to a charge termination voltage of 2.0 V was measured at 25 ° C. Thereafter, the electric double layer capacitor was heated, and when the surface temperature reached 180 ° C., resistance measurement was performed. Resistance was measured at 500 kHz using an impedance analyzer (SP-50 manufactured by biologic).
The resistance measured at 25 ° C. was taken as the initial resistance, and the quotient of the resistance measured at 180 ° C. and the resistance measured at 25 ° C. was taken as the resistance increase. That is, the increase in resistance is represented by the following (Expression 1).
(Expression 1) Resistance increase = resistance at 180 ° C./resistance initial value at 25 ° C. The results obtained by evaluating the resistance and the resistance increase based on the following criteria are shown in Table 3.
· Initial resistance :: "The initial resistance is smaller than the initial resistance without the underlayer (Al foil only). Excellent."
Δ: "The initial resistance is equal to the initial resistance without the underlayer (Al foil only). A practicable level."
X: "The initial resistance is larger than the initial resistance without the underlayer (Al foil only). It is inferior."
・ Resistance increase ○: "The resistance increase is 5 times or more and less than 10 times the initial resistance. It is excellent."
Δ: “The increase in resistance is more than 3 times and less than 5 times the initial resistance. The effect is not sufficient but it can be used.”
X: "The increase in resistance is less than 3 times the initial resistance. The current blocking effect is low. It is inferior."

<Positive material ink for positive electrode for lithium ion capacitor>
85 parts of activated carbon (specific surface area: 1800 m ² / g) as active material, 5 parts of conductive aid (acetylene black: Denka black HS-100, manufactured by Denka), carboxymethylcellulose (CMC Daicel # 1190, manufactured by Daicel Chemical Industries, Ltd.) 8 A mixed ink for positive electrode was prepared by mixing 3.3 parts (2 parts as solid content) of a part and a binder (polytetrafluoroethylene 30-J: 60% aqueous dispersion manufactured by Mitsui-Dupont Fluorochemicals).

<Positive Electrode for Lithium Ion Capacitor with Base Layer (Example 18, Comparative Example 8)>
After applying the above-mentioned mixture ink for positive electrode for lithium ion capacitor on the current collector with an underlayer (1) of Example 1 and the current collector with an underlayer of Comparative Example 1 (17) using a doctor blade After drying by heating under reduced pressure and rolling treatment using a roll press, positive electrodes (25) and (26) having a thickness of 60 μm were produced.
<Negative material ink for negative electrode for lithium ion capacitor>
90 parts of graphite, 5 parts of conductive support agent (acetylene black: Denka black HS-100, manufactured by Denka Co., Ltd.) and 175 parts of 2% by mass aqueous solution of hydroxyethyl cellulose (3.5 parts as solid content) as a negative electrode active material are put in a mixer Mix and mix 26.3 parts of water and 3.75 parts (1.5 parts as solid content) of styrene butadiene emulsion (TRD 2001, manufactured by JSR, 40% aqueous dispersion) to prepare a negative mix ink did.

<Anode for lithium ion capacitor without base layer>
The above negative electrode mixture ink for lithium ion capacitors is coated on a copper foil with a thickness of 20 μm as a current collector using a doctor blade, and then it is dried by heating under reduced pressure and rolled by a roll press. A negative electrode having a thickness of 45 μm was produced.

<Lithium ion capacitor>
A positive electrode shown in Table 4 and a negative electrode previously half-doped with lithium ions are prepared in a size of 16 mm in diameter, respectively, and a separator (porous polypropylene film) inserted between them and an electrolytic solution (ethylene carbonate) A non-aqueous electrolytic solution in which LiPF ₆ was dissolved at a concentration of 1 M in a mixed solvent in which dimethyl carbonate and diethyl carbonate were mixed at a ratio of 1: 1: 1 (volume ratio) was produced. The lithium ion half doping was performed by sandwiching a separator between the negative electrode and lithium metal in a beaker cell, and doping the negative electrode with lithium ions so as to be about half the capacity of the negative electrode. Further, the lithium ion capacitor was carried out in a argon gas substituted glove box, and after producing the lithium ion capacitor, the following electric characteristics were evaluated.

(Charge / discharge cycle characteristics)
About the obtained lithium ion capacitor, charging / discharging measurement was performed using the charging / discharging apparatus.

  After charging to a charge termination voltage of 4.0 V at a charge current of 10 C rate, constant current discharge was performed at a discharge current of 10 C rate until reaching a discharge termination voltage of 2.0 V. The charge / discharge cycle of these five cycles is repeated with one cycle of these charge / discharge cycles, and the discharge capacity of the fifth cycle is taken as the initial discharge capacity. (The initial discharge capacity is 100% maintenance rate).

  Next, charging was performed at a charge termination voltage of 4.0 V at a charge current of 10 C rate in a 50 ° C. constant temperature bath, and then constant current discharge was performed at a discharge current of 10 C rate until reaching a discharge termination voltage of 2.0 V. The charge / discharge cycle was repeated 500 times to calculate the discharge capacity retention rate (percentage of the 500th discharge capacity to the first discharge capacity) (the closer to 100%, the better).

:: “Discharge capacity retention rate is 95% or more. Especially excellent.”
△: “Discharge capacity maintenance rate is 90% or more and less than 95%. There is no problem at all.”
Δ: “Discharge capacity retention rate is 85% or more and less than 90%. There is a problem but usable level.”
X: "The discharge capacity retention rate is less than 85%. There is a problem in practical use and can not be used."
(Resistance measurement)
Resistance measurement was performed at 25 ° C. for the lithium ion capacitor which was charged to a charge termination voltage of 4.0 V at a charge current of 10 C rate. Thereafter, the lithium ion capacitor was heated, and when the surface temperature reached 180 ° C., resistance measurement was performed. Resistance was measured at 500 kHz using an impedance analyzer (SP-50 manufactured by biologic).
The resistance measured at 25 ° C. was taken as the initial resistance, and the quotient of the resistance measured at 180 ° C. and the resistance measured at 25 ° C. was taken as the resistance increase. That is, the increase in resistance is represented by the following (Expression 1).
(Expression 1) Resistance increase = resistance at 180 ° C./resistance initial value at 25 ° C. The results obtained by evaluating the resistance and the resistance increase based on the following criteria are shown in Table 4.
· Initial resistance :: "The initial resistance is smaller than the initial resistance without the underlayer (Al foil only). Excellent."
Δ: "The initial resistance is equal to the initial resistance without the underlayer (Al foil only). A practicable level."
X: "The initial resistance is larger than the initial resistance without the underlayer (Al foil only). It is inferior."
・ Resistance increase ○: "The resistance increase is 5 times or more and less than 10 times the initial resistance. It is excellent."
Δ: “The increase in resistance is more than 3 times and less than 5 times the initial resistance. The effect is not sufficient but it can be used.”
X: "The increase in resistance is less than 3 times the initial resistance. The current blocking effect is low. It is inferior."

  Further, as shown in Tables 3 and 4, it was confirmed that the same effects as those of the examples of the lithium ion secondary battery can be obtained even with an electric double layer capacitor and a lithium ion capacitor.

From the above results, according to the present invention, when the internal temperature of the electrical storage device rises sharply due to overcharging, internal short circuit or the like, the current flow is suppressed by increasing the internal resistance. Thus, a conductive composition for forming a storage device such as a non-aqueous electrolyte secondary battery having a function of enhancing the safety of the storage device can be provided.

Claims (9)

A conductive composition comprising a conductive carbon material (A), water-dispersed olefin resin fine particles (B), a polyvalent cationic compound (C), and an aqueous liquid medium (D) Conductive composition containing 0.01 to 0.5% by mass of solid content mass of the polyvalent cationic compound (C) in solid content of the conductive composition, and the conductive composition is coated A conductive composition having a coating film gloss value of 1 to 10. The conductive composition according to claim 1, wherein the multivalent cationic compound (C) is a water-soluble multivalent metal compound or a water-dispersed fine particle exhibiting a positive zeta potential. The conductive composition according to claim 1 or 2, wherein the water-dispersed olefin resin fine particles (C) exhibit a negative zeta potential. The mass ratio (B1) / (A) of the conductive carbon material (A) to the solid content (B1) of the water-dispersed olefin resin fine particles (B) is 1 to 5; 3. The conductive composition according to any one of the above. Furthermore, 10-50 mass% of water-soluble resin (E) is contained in solid content of a conductive composition, The conductive composition in any one of the Claims 1-4 characterized by the above-mentioned. The conductive composition according to any one of claims 1 to 5, which is for forming a base layer of an electrode for a storage device. A current collector with a base layer for a storage battery device, comprising a current collector and a base layer formed of the conductive composition according to any one of claims 1 to 6. A current collector, an underlayer formed of the conductive composition according to any one of claims 1 to 6, and a mixture layer formed of an electrode-forming composition containing an electrode active material and a binder Storage device electrode. An electrical storage device comprising a positive electrode, a negative electrode, and an electrolytic solution, wherein at least one of the positive electrode and the negative electrode is an electrode for a storage device according to claim 8.