Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
• • H—ELECTRICITY
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  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• • H—ELECTRICITY
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  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
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  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • H—ELECTRICITY
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  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
  • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/581—Chalcogenides or intercalation compounds thereof
  • H01M4/5815—Sulfides
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  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
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  • H01M4/00—Electrodes
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  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
  • H01M4/602—Polymers
  • H01M4/604—Polymers containing aliphatic main chain polymers
• • H—ELECTRICITY
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  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
  • H01M4/622—Binders being polymers
  • H01M4/623—Binders being polymers fluorinated polymers
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  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/624—Electric conductive fillers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/624—Electric conductive fillers
  • H01M4/625—Carbon or graphite
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/021—Physical characteristics, e.g. porosity, surface area
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/028—Positive electrodes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to a composition and additive for forming an electrode.
• Lithium-ion secondary batteries have a high energy density per unit weight and volume, which contributes to making electronic devices smaller and lighter.
• the spread of electric vehicles has accelerated as part of efforts toward zero-emission automobiles, and there is a demand for even lower resistance, longer life, higher capacity, safety, and lower cost.
• Lithium-ion batteries generally have a three-layer structure of a positive electrode, a separator, and a negative electrode, which contains an electrolyte.
• the positive and negative electrodes are manufactured, for example, by coating a current collector with an electrode slurry made by mixing an active material, a conductive material, and a binder.
• the mainstream method for manufacturing negative electrodes is to coat the negative electrode slurry on copper foil, which serves as the current collector, and then dry it.
• the mainstream method for manufacturing positive electrodes is to prepare a positive electrode slurry using an organic solvent such as N-methyl-2-pyrrolidone as the solvent, and then coat it on aluminum foil, which serves as the current collector.
• Inorganic compounds such as transition metal oxides and transition metal chalcogens that contain alkali metals are known as positive electrode active materials for lithium-ion secondary batteries that can obtain a battery voltage of around 4 V.
• highly alkaline positive electrode active materials that contain large amounts of nickel and manganese are used to obtain high-capacity lithium-ion secondary batteries.
• high-nickel positive electrode active materials such as Li x NiO 2 have a high discharge capacity and are attractive positive electrode materials, but they contain alkaline components such as LiOH, Li 2 O, LiHCO 3 , and Li 2 CO 3 on their surface that are produced by proton exchange reactions with raw material residues or moisture, and by reactions with moisture and carbon dioxide in the air.
• the electrode slurry When such positive electrode active materials are used, the electrode slurry will thicken or gel, causing it to gradually lose fluidity. When the electrode slurry loses fluidity, not only does it become difficult to achieve a uniform coating thickness, but in some cases, coating may not be possible, resulting in waste of material.
• the main cause of this is thought to be that during the process of manufacturing the positive electrode, alkaline components present on the surface of the positive electrode active material, in the presence of trace amounts of moisture, promote the dehydrofluorination reaction of the fluorine-based binder, such as polyvinylidene fluoride (PVdF), which has a vinylidene fluoride structure and is used as a binder.
• PVdF polyvinylidene fluoride
• the alkaline components corrode the aluminum foil that is generally used as the current collector for the positive electrode, thereby increasing the resistance of the battery.
• the alkaline components also react with the electrolyte inside the battery, increasing the resistance of the battery and potentially shortening its lifespan.
• the thickening and gelling mentioned above can be suppressed by handling the raw materials and electrode slurry in a dry environment and controlling the water content, but the entire mass production process from preparing the electrode slurry to manufacturing the battery requires large-scale equipment, and the use of large amounts of electricity leads to increased costs and increased environmental impact, which can be problematic.
• Patent Document 1 discloses a technique for suppressing gelation of an electrode slurry by preparing the electrode slurry (positive electrode material slurry) so that it does not become strongly alkaline even when dispersed in water.
• preparing an electrode slurry so that it does not become strongly alkaline using the method described in Patent Document 1 not only requires strict pH control, but also requires a process in which the positive electrode active material is dispersed in water, filtered from the dispersion to extract the positive electrode active material, and then dried. This results in cumbersome work and reduced yields.
• the above-mentioned process may cause a decrease in the performance of the positive electrode active material itself.
• Patent Document 2 reports a technology that uses a compound such as ultra-high molecular weight (weight average molecular weight of 2.2 million or more) polyethylene oxide to bind water through interaction with water (e.g., hydrogen bonding), thereby suppressing the reaction between the alkaline component of the positive electrode active material and water, thereby suppressing thickening and gelation.
• ultra-high molecular weight polymers with strong thickening effects have handling problems, such as the time and cost required for uniform dissolution processing in a solvent, and the difficulty of making a high-concentration solution.
• the above-mentioned ultra-high molecular weight polymers have a high ability to bind water, there is a concern that the polymer itself may bring in water, and to prevent this, strict management of prior drying is required.
• Patent Document 3 JP Patent Publication 9-306502 A and Patent Document 4 (JP Patent Publication 10-79244 A) propose adding an organic acid or an inorganic acid to the positive electrode of a lithium-ion secondary battery to suppress gelation of the electrode slurry (positive electrode mixture slurry).
• Patent Document 3 maleic acid, citraconic acid, and malonic acid are used in the electrode slurry (positive electrode paste), and in Patent Document 4, acetic acid, phosphoric acid, sulfuric acid, and the like are used in the positive electrode mixture.
• a large amount of acid must be added to neutralize the alkali, which may result in a decrease in the energy density of the battery and an increase in the resistance of the battery.
• the acid corrodes the device for producing the electrode.
• the high acidity of the organic acid or inorganic acid causes a neutralization reaction with the lithium ions in the active material, which may lead to a problem of deterioration of the battery performance.
• Patent Document 5 reports a method in which the positive electrode active material is treated with fluorine gas and the remaining LiOH is fixed as LiF, thereby preventing gelation and suppressing gas generation.
• fluorine gas is highly toxic and difficult to handle, and LiF produced as a by-product increases the internal resistance of the battery, reducing capacity, and capacity also decreases due to corrosion of the positive electrode active material by fluorine gas.
• the residual fluorine reacts with traces of moisture present in the active material and electrolyte to produce hydrogen fluoride, which is prone to cycle deterioration.
• Patent Document 6 reports that unreacted lithium hydroxide and impurities derived from the raw materials can be removed by washing with an aqueous solution containing a lithium salt.
• this method such as the increased environmental load caused by the wastewater generated during washing and the costs associated with treating the wastewater.
• the present invention aims to provide an electrode-forming composition that can suppress thickening and gelling of electrode slurries using a simple method, thereby improving storage stability, increasing the solids concentration, and suppressing battery deterioration, as well as an additive that is effective in suppressing gelling of electrode-forming compositions.
• the inventors have conducted extensive research to achieve the above object, and have found that by adding a stabilizing component consisting of a specific heterocycle-containing compound (first component) and a compound (second component) that chemically reacts with the heterocycle-containing compound to an electrode slurry containing at least a positive electrode active material, a fluorine-based binder, and a solvent, thickening and gelling of the composition can be suppressed and storage stability can be improved. Furthermore, an electrode made using the electrode-forming composition of the present invention can suppress deterioration in the battery caused by alkaline components and can also improve battery characteristics.
• a battery comprising a stabilizing component, a positive electrode active material, a binder, and a solvent;
• the stabilizing component is a compound (first component) that has a nitrogen-containing five-membered ring and does not contain an oxygen atom in the nitrogen-containing five-membered ring, the compound having a reactive group, and a compound (second component) that chemically reacts with the heterocycle-containing compound; comprising the first component, the second component, and a product formed by reaction of the first component and the second component;
• the electrode-forming composition contains a product obtained by reaction between the first component and the second component.
• the molecule has a reactive group for reacting with the second component.
• the second component is lithium hydroxide or sodium hydroxide, or a compound having a molecular weight of 200 or more, or a polymer having a weight-average molecular weight of 1,000 or more.
• the electrode-forming composition according to any one of 1 to 10 wherein the product is a compound in which the first component and the second component are bonded via an ester bond, a ketone bond, an amide bond, an ether bond, or a siloxane bond.
• a polymer containing a pyrrolidone structure or a nitrile group 16.
• the electrode-forming composition according to any one of 1 to 16 wherein the total content of the first component and the product is 0.001 to 0.5 mass % of the solid content.
• 20. A secondary battery having 19 electrodes. 21.
• An additive for an electrode slurry comprising a positive electrode active material, a binder, and a solvent comprising: An additive comprising a product obtained by reaction between a heterocycle-containing compound (first component) having a nitrogen-containing five-membered ring and no oxygen atom in the nitrogen-containing five-membered ring, the heterocycle-containing compound having a reactive group, and a compound (second component) that chemically reacts with the heterocycle-containing compound. 22.
• the heterocycle-containing compound is represented by any one of the following formulas (1) to (4):
• R a to R c each independently represent a hydrogen atom, a halogen atom, a carboxy group, a hydroxy group, a thiol group, an amino group, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an alkenyl group having 2 to 6 carbon atoms which may have a substituent, or an aryl group having 6 to 12 carbon atoms which may have a substituent;
• R a and R b may be bonded to each other to form a ring having 4 to 12 carbon atoms which may have a substituent;
• Each L is independently a single bond, a carbonyl group, an ether bond, an ester bond, or an amide bond;
• Z is N or C-L-R c ;
• X a and X b each independently represent a hydrogen atom, a lithium atom, a sodium
• the molecule has a reactive group for reacting with the second component.
• the electrode-forming composition of the present invention is resistant to thickening and gelling and has high storage stability, making it suitable for use in forming positive electrodes for energy storage devices.
• an energy storage device is manufactured with an electrode made using this composition, it is expected to provide benefits such as improved quality and yield due to the improved storage stability of the composition, reduced costs and reduced environmental impact due to a higher concentration of solids, and suppression of deterioration within the battery caused by alkaline components, which can contribute to reducing the manufacturing costs of energy storage devices and improving battery characteristics.
• a protective film is formed on the surface of the alkaline component by adding a stabilizing component containing a specific heterocycle-containing compound and a compound that chemically reacts with the heterocycle-containing compound to the electrode-forming composition.
• This protective film suppresses the reaction between the alkaline component and the binder, particularly the fluorine-based binder, and as a result, it is possible to suppress the thickening and gelling of the composition, and it is believed that the storage stability is improved.
• the electrode-forming composition of the present invention contains a stabilizing component, a positive electrode active material, a binder, and a solvent.
• the stabilizing component is a component having as its constituent elements a heterocycle-containing compound (first component) having a nitrogen-containing five-membered ring and not containing an oxygen atom in the nitrogen-containing five-membered ring, and a compound (second component) that chemically reacts with the heterocycle-containing compound.
• first component a heterocycle-containing compound having a nitrogen-containing five-membered ring and not containing an oxygen atom in the nitrogen-containing five-membered ring
• a compound (second component) that chemically reacts with the heterocycle-containing compound.
• the heterocycle-containing compound of the first component is different from the solvent in the present invention, and is preferably solid at room temperature.
• solid at room temperature means that the melting point at 1 atmosphere is 25°C or higher.
• the first component is a heterocycle-containing compound having a nitrogen-containing five-membered ring and a reactive group that does not contain an oxygen atom in the nitrogen-containing five-membered ring.
• the nitrogen-containing five-membered ring is preferably a compound in which the only heteroatom contained therein is a nitrogen atom, more preferably a compound in which the nitrogen-containing five-membered ring contains two or three nitrogen atoms, and even more preferably a heterocycle-containing compound represented by any one of the following formulas (1) to (4):
• R a to R c each independently represent a hydrogen atom, a halogen atom, a carboxy group, a hydroxy group, a thiol group, an amino group, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an alkenyl group having 2 to 6 carbon atoms which may have a substituent, or an aryl group having 6 to 12 carbon atoms which may have a substituent; R a and R b may be bonded to each other to form a ring having 4 to 12 carbon atoms which may have a substituent;
• Each L is independently a single bond, a carbonyl group, an ether bond, an ester bond, or an amide bond;
• Z is N or C-L-R c ;
• X a and X b each independently represent a hydrogen atom, a lithium atom, a sodium atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an ary
• the heterocycle-containing compounds represented by the above formulas (2), (3) and (4) may be structural isomers.
• isomers of the heterocycle-containing compound represented by formula (2) include the heterocycle-containing compounds represented by the following formulas (2-A) to (2-C)
• isomers of the heterocycle-containing compound represented by formula (3) include the heterocycle-containing compounds represented by the following formulas (3-A) to (3-E)
• isomers of the heterocycle-containing compound represented by formula (4) include the heterocycle-containing compounds represented by the following formulas (4-A) to (4-G).
• the alkyl group having 1 to 6 carbon atoms may be any of linear, branched, and cyclic, and specific examples thereof include linear or branched alkyl groups having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, and an n-hexyl group; and cyclic alkyl groups having 3 to 6 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.
• Examples of the alkenyl group having 2 to 6 carbon atoms represented by R a to R c include an ethenyl group, an n-1-propenyl group, an n-2-propenyl group, a 1-methylethenyl group, an n-1-butenyl group, an n-2-butenyl group, an n-3-butenyl group, a 2-methyl-1-propenyl group, a 2-methyl-2-propenyl group, a 1-ethylethenyl group, a 1-methyl-1-propenyl group, a 1-methyl-2-propenyl group, and an n-1-pentenyl group.
• Examples of the aryl group having 6 to 12 carbon atoms represented by R a to R c include a phenyl group, a tolyl group, a 1-naphthyl group, and a 2-naphthyl group.
• Examples of the ring having 4 to 12 carbon atoms formed by bonding together of R a and R b include a cyclopentane ring, a cyclohexane ring, a benzene ring, a naphthalene ring, a triazole ring, a pyridine ring, and a pyrazine ring.
• the R a to R c may have a substituent.
• the substituent include a carboxy group, a hydroxy group, an aldehyde group, an ester group, a ketone group, an amino group, a phenyl group, a halogen atom, an alkoxysilyl group, an epoxy group, a carboxylic acid chloride group, and a thiol group.
• the alkoxysilyl group include a trimethoxysilyl group, a dimethoxymethylsilyl group, a methoxydimethylsilyl group, a triethoxysilyl group, a diethoxymethylsilyl group, and an ethoxydimethylsilyl group.
• a carboxy group is preferred.
• the number of the substituents is preferably 1 to 6, and more preferably 1 to 3.
• R a to R c include a hydrogen atom, a carboxy group, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, and a ring formed by R a and R b bonding to each other and having 4 to 12 carbon atoms and optionally having a substituent.
• R a to R c a hydrogen atom, a carboxy group, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, and an optionally substituted aromatic ring having 4 to 12 carbon atoms formed by R a and R b bonding to each other are more preferable.
• R a to R c a hydrogen atom, a carboxy group, an optionally substituted alkyl group having 1 to 3 carbon atoms, an optionally substituted aryl group having 6 to 10 carbon atoms, and an optionally substituted aromatic ring having 6 to 10 carbon atoms formed by bonding together of R a and R b are even more preferable.
• R a to R c a hydrogen atom, a carboxy group, a methyl group, a phenyl group, and a benzene ring which may have a substituent and which is formed by R a and R b bonding to each other are more preferable.
• L is preferably a single bond, an ester bond, or an amide bond, and more preferably a single bond.
• the alkyl group having 1 to 6 carbon atoms represented by Xa and Xb may be any of linear, branched, and cyclic, and specific examples thereof include linear or branched alkyl groups having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, and an n-hexyl group; and cyclic alkyl groups having 3 to 6 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.
• Examples of the aryl group having 6 to 12 carbon atoms represented by Xa and Xb include a phenyl group, a tolyl group, a 1-naphthyl group, and a 2-naphthyl group.
• the above Xa and Xb may have a substituent.
• substituents include a carboxy group, a hydroxy group, an aldehyde group, an ester group, a ketone group, an amino group, a phenyl group, a halogen atom, an alkoxysilyl group, an epoxy group, a carboxylic acid chloride group, and a thiol group.
• alkoxysilyl group include a trimethoxysilyl group, a dimethoxymethylsilyl group, a methoxydimethylsilyl group, a triethoxysilyl group, a diethoxymethylsilyl group, and an ethoxydimethylsilyl group.
• a carboxy group, an amino group, a hydroxy group, and an alkoxysilyl group are preferred, a carboxy group, an amino group, and a hydroxy group are more preferred, and a carboxy group is even more preferred.
• the alkyl group having 1 to 10 carbon atoms represented by R d may be any of linear, branched, and cyclic, and specific examples thereof include linear or branched alkyl groups having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, a neopentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, and an n-decyl group; and cyclic alkyl groups having 3 to 10 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohex
• Examples of the alkanol group having 1 to 10 carbon atoms represented by R d include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group, a hydroxyhexyl group, a hydroxyoctyl group, a hydroxynonyl group, and a hydroxydecyl group.
• Examples of the alkenyl group having 2 to 10 carbon atoms represented by R d include an ethenyl group, an n-1-propenyl group, an n-2-propenyl group, a 1-methylethenyl group, an n-1-butenyl group, an n-2-butenyl group, an n-3-butenyl group, a 2-methyl-1-propenyl group, a 2-methyl-2-propenyl group, a 1-ethylethenyl group, a 1-methyl-1-propenyl group, a 1-methyl-2-propenyl group, an n-1-pentenyl group, and an n-1-decenyl group.
• Examples of the aryl group having 6 to 12 carbon atoms represented by R d include a phenyl group, a tolyl group, a 1-naphthyl group, and a 2-naphthyl group.
• X a and X b are preferably a hydrogen atom, a lithium atom, a sodium atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, and --CH 2 NR d 2 .
• Xa and Xb are preferably a hydrogen atom, a lithium atom, a sodium atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, an optionally substituted aryl group having 6 to 10 carbon atoms, and --CH 2 NR d 2 .
• a hydrogen atom, a lithium atom, a sodium atom, an optionally substituted alkyl group having 1 to 3 carbon atoms, an optionally substituted aryl group having 6 to 8 carbon atoms, and --CH.sub.2NR.sub.d2 are more preferable.
• a hydrogen atom, a lithium atom, a methyl group, a phenyl group and --CH 2 NR d 2 are more preferable.
• an alkyl group having 1 to 3 carbon atoms and an aryl group having 6 to 10 carbon atoms are preferable, and a methyl group and a phenyl group are more preferable.
• the heterocycle-containing compounds represented by formulas (1) to (4) have reactive groups in their molecules for reacting with the second component described below, and examples of the reactive groups include those having reactivity among the substituents exemplified in the description of R a to R c , X a and X b .
• groups that can be reactive groups include a carboxy group, a hydroxy group, an aldehyde group, an ester group, a ketone group, an amino group, a halogen atom, an alkoxysilyl group, an epoxy group and a carboxylic acid chloride group, and in consideration of the reactivity with the second component, a carboxy group, an amino group, a hydroxy group and an alkoxysilyl group are preferred, a carboxy group, an amino group and a hydroxy group are more preferred, and a carboxy group is even more preferred.
• the number of reactive groups is not particularly limited, but taking into consideration the electrochemical stability of the compound, 1 to 3 is preferable, and 1 is more preferable.
• the reactive group may be present in any of R a to R c , X a and X b .
• R a to R c has the reactive group
• R a and R b have the reactive group in a ring having 4 to 12 carbon atoms formed by bonding to each other
• R a and R b have the reactive group in an aromatic ring having 6 to 10 carbon atoms formed by bonding to each other
• R a and R b have the reactive group in a benzene ring formed by bonding to each other.
• heterocycle-containing compounds represented by the above formulas (1) to (4) are preferably heterocycle-containing compounds represented by the following formulas (1a) to (4a).
• heterocycle-containing compound is more preferably a heterocycle-containing compound represented by the following formula (5):
• Ar 1 is an aromatic ring having 4 to 12 carbon atoms which may have a substituent, or an aliphatic ring having 4 to 10 carbon atoms which may have a substituent.
• Z and Xa are the same as above.
• heterocycle-containing compounds represented by the following formula (6) are even more preferable.
• heterocycle-containing compound represented by the above formula (1) include the heterocycle-containing compounds represented by the following formulas (1-1) to (1-11).
• heterocycle-containing compound represented by the above formula (2) include the heterocycle-containing compounds represented by the following formulas (2-1) to (2-6).
• heterocycle-containing compound represented by the above formula (3) include the heterocycle-containing compounds represented by the following formulas (3-1) to (3-4).
• heterocycle-containing compound represented by the above formula (4) examples include the heterocycle-containing compounds represented by the following formulas (4-1) to (4-4).
• the second component is a compound that chemically reacts with the heterocycle-containing compound (first component).
• the second component include compounds having an oxazoline group, an aldehyde group, a carboxy group, a hydroxy group, an amino group, an alkoxysilyl group, an epoxy group, or a carboxylic acid chloride group; as well as lithium hydroxide, sodium hydroxide, lithium hydrogen carbonate, and lithium carbonate.
• compounds having an oxazoline group or an amino group, lithium hydroxide, and sodium hydroxide are preferred.
• the compound having an oxazoline group, an aldehyde group, a carboxy group, a hydroxy group, an amino group, an alkoxysilyl group, an epoxy group, or a carboxylic acid chloride group may be a polymer or a non-polymer compound (a non-polymer type compound).
• the second component is a non-polymeric compound
• lithium hydroxide or sodium hydroxide or a compound with a molecular weight of 200 or more is preferred.
• the molecular weight There is no particular upper limit to the molecular weight, but it is usually preferred that it be 800 or less.
• the weight average molecular weight is preferably at least 1,000, and more preferably at least 5,000.
• the upper limit of the weight average molecular weight is not particularly limited, but is usually preferably at most 1,000,000.
• the weight average molecular weight is a polystyrene-equivalent value determined by gel permeation chromatography (GPC) (the same applies hereinafter).
• non-polymeric compounds include lithium hydroxide, sodium hydroxide, 2-(1,3-Phenylene)bis-2-oxazoline (PBO), 1,3,5-tris(oxiran-2-ylmethyl)-1,3,5-triazinane-2,4,6-trione, trimesic acid, 1,2,3,4-butanetetracarboxylic acid, and benzene-1,2,4,5-tetracarboxylic acid.
• the compounds exemplified above may be synthesized by known synthesis methods, but are also available as commercial products.
• oxazoline polymers include Epocross WS-300 (manufactured by Nippon Shokubai Co., Ltd., solids concentration 10% by mass, aqueous solution), Epocross WS-700 (manufactured by Nippon Shokubai Co., Ltd., solids concentration 25% by mass, aqueous solution), Epocross WS-500 (manufactured by Nippon Shokubai Co., Ltd., solids concentration 39% by mass, water/1-methoxy-2-propanol solution), Poly(2-ethyl-2-oxazoline) (Aldrich), Poly(2-ethyl-2-oxazoline) (Alfa Aesar), Poly(2-ethyl-2-oxazoline) (VWR International, LLC), etc.
• polyethyleneimine products include Epomin (polyethyleneimine) SP-003, SP-006, SP-012, SP-018, SP-020, and P-1000 manufactured by Nippon Shokubai Co., Ltd.
• polyallylamine products include PAA-01, PAA-03, PAA-05, PAA-08, PAA-15C, and PAA-25 manufactured by Nittobo Medical Co., Ltd.; and Polyment (aminoethylated acrylic polymer) NK-100PM, NM-200PM, NK-350, and NK-380 manufactured by Nippon Shokubai Co., Ltd.
• polyvinyl alcohol products include V series, VC-10, VC-13, VC-20, VF-17, VF-20, VM-17, VT-13KY, VP-18, and VP-20 manufactured by Nippon Vinyl Acetate Poval Co., Ltd.; Kuraray Poval 3-98, 5-98, 28-98, 60-98, 27-96, 3-88, 5-88, 22-88, 44-88, 95-88, 48-80, and L-10 manufactured by Kuraray Co., Ltd.; and Denka Poval K-05, K-17E, K-17C, H-12, H-17, H-24, B-05, B-17, B-20, B-24, and B-33 manufactured by Denka Co., Ltd.
• polyacrylic acid products include the Aron, Julimer, Rheogic, and Junron series manufactured by Toa Gosei Co., Ltd., the Viscomate series manufactured by Showa Denko K.K., and the Aqualic series manufactured by Nippon Shokubai Co., Ltd., etc.
• the stabilizing component contains the first component and the second component as constituent elements, and as long as they are reacted after film formation, they may exist as is at the composition stage, or some or all of them may react to form a product formed by the reaction of the first component and the second component.
• Specific preferred examples of the product obtained by the reaction of the first component and the second component include those shown below, but are not limited to these.
• ⁇ Natural product of lithium hydroxide of a heterocycle-containing compound represented by non-polymer type formula (1-1) Reaction product of a heterocycle-containing compound represented by formula (1-1) and PBO ⁇ Reaction product of a heterocycle-containing compound represented by polymer type formula (1-1) and an oxazoline polymer Reaction product of a heterocycle-containing compound represented by formula (1-1) and polyethyleneimine Reaction product of a heterocycle-containing compound represented by formula (1-5) and an oxazoline polymer
• the total content of the first component and the product is preferably 0.001 to 4 mass%, more preferably 0.001 to 2 mass%, even more preferably 0.001 to 0.5 mass% of the solid content, even more preferably 0.001 to 0.3 mass%, and particularly preferably 0.001 to 0.2 mass%.
• An even more preferable lower limit of the total content is 0.01 mass% of the solid content.
• the stabilizing component of the present invention can be suitably used as a gelation inhibitor for an electrode slurry containing a positive electrode active material, a binder, and a solvent. Furthermore, the present invention can be suitably applied as a method for suppressing gelation of an electrode slurry by adding the stabilizing component to the electrode slurry.
• the positive electrode active material can be appropriately selected from various active materials conventionally used in electrodes for energy storage devices such as secondary batteries, and can be used by satisfying the above conditions.
• chalcogen compounds or lithium ion-containing chalcogen compounds capable of adsorbing and releasing lithium ions, polyanion compounds, sulfur alone and its compounds, etc. can be used.
• a positive electrode active material containing 30% by mass or more of S, Fe, or Ni it is preferable to use a positive electrode active material containing 30% by mass or more of S, Fe, or Ni.
• a positive electrode active material containing 30% by mass or more of Ni is more preferable, a positive electrode active material containing 40% by mass or more of Ni is even more preferable, a positive electrode active material containing 50% by mass or more of Ni is even more preferable, and a positive electrode active material containing 55% by mass or more of Ni is particularly preferable.
• the upper limit is not particularly limited, but is usually 65% by mass or less.
• lithium ion -containing chalcogen compounds include LiNiO2 , LixNiyM1 -yO2 ( M represents at least one metal element selected from Co, Mn, Ti, Cr, V, Al, Sn, Pb, and Zn; 0.05 ⁇ x ⁇ 1.10 , 0.3 ⁇ y ⁇ 1.0 ) , LiaNi (1-xy) CoxM1yM2zO2 ( M1 represents at least one element selected from the group consisting of Mn and Al, M2 represents at least one element selected from the group consisting of Zr, Ti, Mg, B, Zr, W, and V; 1.00 ⁇ a ⁇ 1.50, 0.00 ⁇ x ⁇ 0.50, 0 ⁇ y ⁇ 0.50, 0.000 ⁇ z ⁇ 0.020), and the like.
• Examples of polyanion compounds include LiFePO4 , LiaMnbFecDdPO4 ( 1.00 ⁇ a ⁇ 1.15, 0.01 ⁇ b ⁇ 0.99, 0.01 ⁇ c ⁇ 0.99, 0.00 ⁇ d ⁇ 0.10, D is selected from Co, Mn, Ti , Cr , V, Al, Sn, Pb, and Zn, and at least a part of the compound has an olivine structure).
• Examples of sulfur compounds include sulfur, Li2S , FeS2 , TiS2 , MoS2 , and rubeanic acid. These positive electrode active materials can be used alone or in combination of two or more.
• LiaNi (1-xy) CoxM1yM2zXwO2 ( M1 represents at least one selected from the group consisting of Mn and Al , M2 represents at least one selected from the group consisting of Zr, Ti, Mg, W and V, and 1.00 ⁇ a ⁇ 1.50 , 0.00 ⁇ x ⁇ 0.50, 0 ⁇ y ⁇ 0.50, 0.000 ⁇ z ⁇ 0.020, 0.000 ⁇ w ⁇ 0.020) is preferred.
• These active materials may be used alone or in combination of two or more.
• the content of the positive electrode active material is preferably 88.0 to 99.949% by mass, more preferably 88.0 to 99.899% by mass, and even more preferably 95.0 to 99.0% by mass, based on the solid content.
• the binder can be appropriately selected from known materials and is not particularly limited. Specific examples include fluorine-based binders such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene; copolymers containing at least one monomer selected from the group consisting of vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene, and non-aqueous binders such as polyimide, ethylene-propylene-diene terpolymer, styrene-butadiene rubber, polyethylene, and polypropylene.
• PVdF polyvinylidene fluoride
• copolymers containing at least one monomer selected from the group consisting of vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene and non-aqueous binders such as polyimide, ethylene-propylene-diene terpolymer, styrene-butad
• the fluorine-based binder is preferably modified with a polar functional group such as a carboxy group or a hydroxy group.
• the polar functional group can be confirmed by the presence or absence of a clear peak detected in the range of 10 to 15 ppm in measurement by a nuclear magnetic resonance apparatus (NMR apparatus).
• NMR apparatus nuclear magnetic resonance apparatus
• the binders can be used alone or in combination of two or more.
• the content of the binder is preferably 0.05 to 8 mass% of the solid content, more preferably 0.05 to 5 mass%, even more preferably 0.05 to 4 mass%, even more preferably 0.1 to 3 mass%, particularly preferably 0.2 to 2 mass%, and most preferably 0.3 to 1.5 mass%.
• the electrode-forming composition of the present invention may further contain a conductive assistant to improve electrical conductivity.
• a conductive assistant include carbon materials such as graphite, carbon black, acetylene black (AB), vapor-grown carbon fiber, carbon nanotube (CNT), carbon nanohorn, and graphene, and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyacene.
• the composition does not contain graphene, and it is preferable to use carbon black, acetylene black, vapor-grown carbon fiber, carbon nanotube, and carbon nanohorn, and it is more preferable to use carbon black, acetylene black, and carbon nanotube.
• the conductive assistant may be used alone or in combination of two or more kinds.
• the conductive assistant When the conductive assistant is included, its content is not particularly limited, but is preferably 0.05 to 5 mass% of the solid content, more preferably 0.05 to 4 mass%, even more preferably 0.1 to 3 mass%, and even more preferably 0.2 to 2 mass%. By keeping the content of the conductive assistant within the above range, good electrical conductivity can be obtained.
• the electrode-forming composition of the present invention may further contain a dispersant to improve the dispersibility of the active material and the conductive assistant.
• the dispersant may be appropriately selected from those conventionally used as dispersants for conductive carbon materials such as CNT, but from the viewpoint of stability in the battery, it is preferable to contain a nonionic polymer.
• the nonionic polymer include polyvinylpyrrolidone (PVP) and polymers having at least one group selected from the group consisting of a nitrile group, a hydroxy group, a carbonyl group, an amino group, a sulfonyl group, and an ether group.
• polymer examples include polyvinyl alcohol, polyacrylonitrile, polylactic acid, polyester, polyimide, polyphenyl ether, polyphenyl sulfone, polyethyleneimine, polyaniline, and the like.
• a polymer containing a pyrrolidone structure or a nitrile group is preferable, and polyvinylpyrrolidone and polyacrylonitrile are more preferable.
• the dispersant may be used alone or in combination of two or more types.
• the dispersant When the dispersant is contained, its content is not particularly limited, but is preferably 0.001 to 0.5 mass % of the solid content, more preferably 0.001 to 0.3 mass %, and even more preferably 0.001 to 0.2 mass %. An even more preferable lower limit of the content of the dispersant is 0.01 mass % of the solid content.
• the total amount of the first component, the product, and the dispersant is preferably 0.001 to 1 mass % of the solid content, and more preferably 0.01 to 1 mass %.
• the electrode-forming composition of the present invention contains a solvent.
• the solvent is not particularly limited as long as it is a solvent that has been conventionally used in the preparation of an electrode-forming composition, and examples of the solvent include water; ethers such as tetrahydrofuran (THF), diethyl ether, and 1,2-dimethoxyethane (DME); halogenated hydrocarbons such as methylene chloride, chloroform, and 1,2-dichloroethane; amides such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methyl-2-pyrrolidone (NMP); ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and t-butanol.
• the solvent examples include alcohols, aliphatic hydrocarbons such as n-heptane, n-hexane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether, glycols such as ethylene glycol and propylene glycol, carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate, and organic solvents such as ⁇ -butyrolactone, dimethyl sulfoxide (DMSO), dioxolane, and sulfolane. These solvents can be used alone or in combination of two or more.
• aliphatic hydrocarbons such as n-heptane, n-hexane, and cyclo
• the binder may be dissolved or dispersed in these solvents before use.
• suitable solvents include water, NMP, DMSO, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ⁇ -butyrolactone, THF, dioxolane, sulfolane, DMF, DMAc, and the like.
• the solvent may be appropriately selected depending on the type of binder.
• a water-insoluble binder such as PVdF
• NMP is suitable
• water is suitable.
• the solids concentration of the electrode-forming composition of the present invention is set appropriately taking into consideration the coatability of the composition and the thickness of the electrode to be formed, but is usually about 60 to 92% by mass, preferably about 65 to 90% by mass, and more preferably about 70 to 85% by mass.
• the viscosity of the electrode-forming composition of the present invention is set appropriately taking into consideration the coating method, the thickness of the electrode to be formed, etc., but is usually about 100 to 2,000,000 mPa ⁇ s, preferably about 300 to 1,000,000 mPa ⁇ s, and more preferably about 400 to 800,000 mPa ⁇ s.
• the above viscosity is a value measured at 25°C using an E-type viscometer.
• the electrode-forming composition of the present invention can be obtained by mixing the above-mentioned components.
• the first and second components of the stabilizing components may be mixed as they are, or a part or all of these may be mixed after forming a product formed by the reaction of the first and second components.
• the additive (stabilizing component) and positive electrode active material may be mixed together with the optional component, or both components may be mixed in advance and then mixed with the optional component. Either method can produce the effects of the present invention.
• the electrode of the present invention comprises an electrode layer made of the above-described electrode-forming composition on at least one surface of a substrate serving as a current collector.
• the method of forming the electrode layer on the substrate includes a method of applying the prepared electrode-forming composition on the substrate to form a coating film, and then drying the coating film. This method is not particularly limited, and various conventionally known methods can be used. Specific examples of the coating method include various printing methods such as offset printing and screen printing, blade coating, dip coating, spin coating, bar coating, slit coating, inkjet printing, and die coating.
• the temperature is preferably about 50 to 400°C, and more preferably about 70 to 150°C.
• Substrates used for the above electrodes include, for example, metal substrates such as platinum, gold, iron, stainless steel, copper, aluminum, and lithium; alloy substrates made of any combination of these metals; oxide substrates such as indium tin oxide (ITO), indium zinc oxide (IZO), and antimony tin oxide (ATO); and carbon substrates such as glassy carbon, pyrolytic graphite, and carbon felt.
• the thickness of the substrate is not particularly limited, but in the present invention, it is preferably 1 to 100 ⁇ m, more preferably 3 to 30 ⁇ m, and most preferably 5 to 25 ⁇ m.
• the thickness of the electrode layer is not particularly limited, but is preferably about 0.01 to 1,000 ⁇ m, and more preferably about 5 to 300 ⁇ m. If the electrode layer is used as an electrode alone, it is preferable that the thickness be 10 ⁇ m or more.
• the electrodes may be pressed as necessary. Any commonly used pressing method may be used, but mold pressing and roll pressing are particularly preferred.
• the pressing pressure is not particularly limited, but is preferably 1 kN/cm or more, more preferably 2 kN/cm or more, and more preferably 5 kN/cm or more.
• the upper limit of the pressing pressure is not particularly limited, but is preferably 50 kN/cm or less.
• the secondary battery of the present invention is equipped with the electrodes described above, and more specifically, is composed of at least a pair of positive and negative electrodes, a separator interposed between the electrodes, and an electrolyte, with the positive electrode being composed of the electrode described above.
• the other components of the battery element may be appropriately selected from conventionally known components.
• Materials used for the separator include, for example, glass fiber, cellulose, porous polyolefin, polyamide, polyester, etc.
• the electrolyte may be either liquid or solid, and may be either aqueous or non-aqueous, but from the viewpoint of easily achieving sufficient performance for practical use, an electrolyte solution composed of an electrolyte salt and a solvent, etc., may be preferably used.
• electrolyte salt examples include lithium salts such as LiPF6 , LiBF4 , LiN( SO2F ) 2 , LiN ( C2F5SO2 ) 2 , LiAsF6 , LiSbF6 , LiAlF4 , LiGaF4 , LiInF4 , LiClO4, LiN( CF3SO2 ) 2 , LiCF3SO3 , LiSiF6 , and LiN( CF3SO2 )( C4F9SO2 ) ;
• the electrolyte salt include metal iodides such as LiBr, NaBr, KBr, CsBr, CaBr, etc., perchlorates and iodides of quaternary imidazolium compounds, and metal bromides such as LiBr, NaBr, KBr, CsBr, and CaBr, etc. These electrolyte salts can be used alone or in combination of two or more .
• non-aqueous solvents include cyclic esters such as ethylene carbonate, propylene carbonate, butylene carbonate, and ⁇ -butyrolactone, ethers such as tetrahydrofuran and dimethoxyethane, chain esters such as methyl acetate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and nitriles such as acetonitrile.
• cyclic esters such as ethylene carbonate, propylene carbonate, butylene carbonate, and ⁇ -butyrolactone
• ethers such as tetrahydrofuran and dimethoxyethane
• chain esters such as methyl acetate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate
• nitriles such as acetonitrile.
• solid electrolyte inorganic solid electrolytes such as sulfide-based solid electrolytes and oxide-based solid electrolytes, and organic solid electrolytes such as polymer-based electrolytes can be suitably used. By using these solid electrolytes, it is possible to obtain an all-solid-state battery that does not use an electrolytic solution.
• Examples of the sulfide-based solid electrolyte include thiolithium-based materials such as Li2S - SiS2 -lithium compound (wherein the lithium compound is at least one selected from the group consisting of Li3PO4 , LiI and Li4SiO4 ) , Li2S - P2O5 , Li2S - B2S5 , and Li2S - P2S5 - GeS2 .
• Li2S - SiS2 -lithium compound wherein the lithium compound is at least one selected from the group consisting of Li3PO4 , LiI and Li4SiO4 ) , Li2S - P2O5 , Li2S - B2S5 , and Li2S - P2S5 - GeS2 .
• polymer solid electrolyte examples include polyethylene oxide materials and polymer compounds obtained by polymerizing or copolymerizing monomers such as hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, ethylene, propylene, acrylonitrile, vinylidene chloride, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, styrene, and vinylidene fluoride.
• the polymer solid electrolyte may contain a supporting salt and a plasticizer.
• the supporting salt contained in the polymer solid electrolyte may be lithium (fluorosulfonylimide), and the plasticizer may be succinonitrile.
• Batteries manufactured using the electrode-forming composition of the present invention have high battery characteristics even though they contain less fluorine binder compared to general secondary batteries.
• the type of secondary battery and the type of electrolyte are not particularly limited, and any type of battery such as a lithium-ion secondary battery, nickel-hydrogen battery, manganese battery, or air battery may be used, but a lithium-ion secondary battery is preferred. There are also no particular limitations on the lamination method or production method.
• the electrode of the present invention described above can be punched out into a specified disk shape and used.
• a lithium-ion secondary battery can be produced by placing one electrode on the lid of a coin cell to which a washer and spacer are welded, placing a separator of the same shape impregnated with an electrolyte on top of that, placing the electrode of the present invention on top with the electrode layer facing down, placing a case and gasket on top, and sealing with a coin cell crimping machine.
• the present invention also provides an additive for an electrode slurry containing a positive electrode active material, a binder, and a solvent, the additive comprising a product of a reaction between a heterocycle-containing compound (first component) having a nitrogen-containing five-membered ring and no oxygen atom in the nitrogen-containing five-membered ring, the heterocycle-containing compound having a reactive group, and a compound (second component) that chemically reacts with the heterocycle-containing compound.
• the additive can be suitably used as a gelation inhibitor for an electrode slurry containing a positive electrode active material, a binder, and a solvent.
• the heterocycle-containing compound of the first component is preferably a solid at room temperature, as described above in the description of the electrode-forming composition.
• the nitrogen-containing five-membered ring is preferably a compound in which the only heteroatom contained therein is a nitrogen atom, more preferably a compound in which the nitrogen-containing five-membered ring contains two or three nitrogen atoms, and even more preferably a heterocycle-containing compound represented by any of the following formulas (1) to (4).
• R a to R c each independently represent a hydrogen atom, a halogen atom, a carboxy group, a hydroxy group, a thiol group, an amino group, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an alkenyl group having 2 to 6 carbon atoms which may have a substituent, or an aryl group having 6 to 12 carbon atoms which may have a substituent; R a and R b may be bonded to each other to form a ring having 4 to 12 carbon atoms which may have a substituent;
• Each L is independently a single bond, a carbonyl group, an ether bond, an ester bond, or an amide bond;
• Z is N or C-L-R c ;
• X a and X b each independently represent a hydrogen atom, a lithium atom, a sodium atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an ary
• the additive may further include at least one selected from the group consisting of a polymer containing a pyrrolidone structure or a nitrile group, and a solvent.
• polymers containing a pyrrolidone structure or a nitrile group include those exemplified in the description of the dispersant for the electrode-forming composition, with polyvinylpyrrolidone and polyacrylonitrile being preferred.
• the additive contains the polymer
• its content is not particularly limited, but is preferably 0.001 to 0.5 mass% of the solid content, more preferably 0.001 to 0.3 mass%, and even more preferably 0.001 to 0.2 mass%.
• An even more preferable lower limit of the content of the polymer is 0.01 mass% of the solid content.
• the above-mentioned solvents include those exemplified in the description of the electrode-forming composition.
• NMP, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, and ethyl methyl carbonate can be particularly preferably used.
• the heterocycle-containing compound represented by any one of the above formulas (1) to (4) is preferably dissolved or dispersed in the solvent, and more preferably dissolved in the solvent.
• the solids concentration of the additive is set appropriately taking into consideration the saturation solubility in the solvent, storage stability, etc., but is usually about 1 to 60 mass%, preferably about 3 to 55 mass%, and more preferably about 3 to 50 mass%.
• the positive electrode active material and binder of the electrode slurry are also the same as those described above.
• Rotation and revolution type mixer Thinky Mixer, atmospheric pressure type ARE-310
• Dry base manufactured by Nihon Spindle Mfg. Co., Ltd.
• E-type viscometer manufactured by Toki Sangyo Co., Ltd., VISCOMETER TV-22, measurement temperature: 25° C., rotor: 1°34′ ⁇ R24. The viscosity was measured 5 minutes after the start of measurement.
• NCA lithium nickel oxide (LiNi 0.88 Co 0.11 Al 0.01 O 2 , manufactured by Ecopro, NCA-034H, Ni ratio: 55% by mass)
• NCM811 Lithium nickel manganese cobalt oxide ( LiNi0.8Co0.1Mn0.1O2 , manufactured by LinYi Gelon LIB Co., Ltd., S-800, Ni ratio: 50% by mass)
• Solef-5140 Polyvinylidene fluoride (PVdF, manufactured by SOLVAY)
• PVdF Polyvinylidene fluoride
• NMP Manufactured by Nippon Refine Co., Ltd.
• a4 4-Vinylpyridine, manufactured by Tokyo Chemical Industry Co., Ltd. a5: Pyridine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. a6: Poly(4-vinylpyridine), manufactured by Sigma-Aldrich a7: Polyacrylic acid, manufactured by Toagosei Co., Ltd., Aron AC-10P, Mw: 5,000 a8: Oxalic acid, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. a9: Phenylboronic acid, manufactured by Cangzhou Pure Science Co., Ltd. a10: Benzoic acid, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.
• a11 Tannic acid, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.
• a12 Water-soluble methylol melamine (Nicalesin S176 (triazine structure)), manufactured by Nippon Carbide Industries Co., Ltd.
• vacuum distillation was performed at 85° C./20 Torr for 2.5 hours, at 120° C./50 Torr for 2 hours, and at 120° C./20 Torr for 0.3 hours, and 52.47 g of NMP was added to obtain a 5 mass % NMP solution of CBT-1/PBO.

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