WO2024057992A1 - 硫黄含有材料、硫黄含有電池材料、電極及び電池 - Google Patents
硫黄含有材料、硫黄含有電池材料、電極及び電池 Download PDFInfo
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- WO2024057992A1 WO2024057992A1 PCT/JP2023/032274 JP2023032274W WO2024057992A1 WO 2024057992 A1 WO2024057992 A1 WO 2024057992A1 JP 2023032274 W JP2023032274 W JP 2023032274W WO 2024057992 A1 WO2024057992 A1 WO 2024057992A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G75/00—Macromolecular compounds obtained by reactions forming a linkage containing sulfur with or without nitrogen, oxygen, or carbon in the main chain of the macromolecule
- C08G75/14—Polysulfides
- C08G75/16—Polysulfides by polycondensation of organic compounds with inorganic polysulfides
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
- C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
- C08F20/42—Nitriles
- C08F20/44—Acrylonitrile
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F8/00—Chemical modification by after-treatment
- C08F8/34—Introducing sulfur atoms or sulfur-containing groups
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- 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
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/134—Electrodes based on metals, Si or alloys
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- 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/137—Electrodes based on electro-active polymers
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- 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
- H01M4/362—Composites
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- 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
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
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- 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
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/381—Alkaline or alkaline earth metals elements
- H01M4/382—Lithium
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- 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
- H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
- H01M4/602—Polymers
- H01M4/604—Polymers containing aliphatic main chain polymers
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- 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
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- 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
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- 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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- 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 disclosure relates to sulfur-containing materials, sulfur-containing battery materials, electrodes, and batteries.
- Batteries are used for various purposes.
- the characteristics of a battery depend on its constituent members such as electrodes, separators, electrolytes, etc., and research and development of each constituent member is actively conducted.
- electrodes the active material in the electrode layer is important, as well as the binder, current collector, etc., and research and development are actively being carried out.
- sulfur-containing materials are known as active materials (see, for example, Patent Documents 1 and 2).
- the sulfur-containing materials used in Patent Document 1 and the like are required to be materials that can form batteries with larger discharge capacity.
- the present disclosure has been made in view of the above problems, and its main purpose is to provide a sulfur-containing material whose discharge capacity can be easily increased.
- the present disclosure includes a sulfur-modified compound, has a total sulfur content of 50% by mass or more, and has a diffraction angle (2 ⁇ ) of 23.0° to 23.4 obtained by powder X-ray diffraction using CuK ⁇ rays.
- the ratio (A/B) of the maximum peak intensity (A) within the range of 1° to the maximum peak intensity (B) within the range of the diffraction angle (2 ⁇ ) of 24.8° to 25.2° is 1 .5 or less (A/B ⁇ 1.5).
- the sulfur-modified compound is preferably a sulfur-modified acrylic compound.
- the present disclosure includes a sulfur-modified compound, has a total sulfur content of 50% by mass or more, has a diffraction angle (2 ⁇ ) of 23.0° to 23.4°, and is obtained by powder X-ray diffraction using CuK ⁇ rays.
- the ratio (A/B) of the maximum peak intensity within the range (A) to the maximum peak intensity (B) within the range of the diffraction angle (2 ⁇ ) of 24.8° to 25.2° is 1.5.
- This is a sulfur-containing battery material characterized by the following (A/B ⁇ 1.5).
- the sulfur-modified compound is preferably a sulfur-modified acrylic compound.
- the present disclosure is an electrode having an electrode layer containing the above-mentioned sulfur-containing material.
- the present disclosure is a battery having the above electrode.
- the electrode is preferably a positive electrode.
- the negative electrode is preferably lithium.
- a sulfur-containing material whose discharge capacity can be easily increased can be provided.
- the sulfur-containing material of the present disclosure contains a sulfur-modified compound, has a total sulfur content of 50% by mass or more, and has a diffraction angle (2 ⁇ ) of 23.0° to 23.0° as determined by powder X-ray diffraction using CuK ⁇ rays. .Ratio (A/B) of the maximum peak intensity (A) within the range of 4° and the maximum peak intensity (B) within the range of the diffraction angle (2 ⁇ ) of 24.8° to 25.2° is 1.5 or less (A/B ⁇ 1.5).
- the sulfur-containing material of the present disclosure includes at least a sulfur-modified compound. That is, the sulfur-containing material may include, for example, sulfur-modified compounds, elemental sulfur, and impurities.
- elemental sulfur can be sulfur that does not form a stable interaction with a sulfur-modified compound.
- the elemental sulfur includes, but is not particularly limited to, ⁇ sulfur, ⁇ sulfur, and ⁇ sulfur having an S 8 structure.
- the discharge capacity is increased, and the discharge capacity is less likely to decrease even after repeated charging and discharging, that is, the cycle characteristics are improved.
- the sulfur-containing material of the present disclosure has excellent flame retardancy, it is possible to improve the safety of the battery.
- organic sulfur is different from elemental sulfur, for example, sulfur that forms a stable interaction within a sulfur-modified compound or that forms a stable interaction with a sulfur-modified compound. Can be sulfur.
- organic sulfur As a result of such a large proportion of organic sulfur, for example, during charging and discharging, it improves the reactivity between sulfur and lithium, and also suppresses the elution and side reactions of lithium polysulfide, effectively increasing the discharge capacity. At the same time, it is possible to achieve the effect of improving cycle characteristics. Furthermore, since the proportion of elemental sulfur in the sulfur contained in the sulfur-containing material is small, it is possible to simultaneously suppress flammability and improve battery safety.
- the organic sulfur may be composed of one sulfur atom that forms stable interactions, or may be composed of multiple sulfur atoms such as disulfide and trisulfide.
- stable interactions include those that do not produce diffraction peaks due to elemental sulfur in powder X-ray diffraction using CuK ⁇ rays, and more specifically, those that do not produce diffraction peaks caused by elemental sulfur (for example, around 23.2°). Examples include those that do not produce strong diffraction peaks at diffraction angles (2 ⁇ ) such as (within the range of 23.4° to 23.4°), such as covalent bonds or ionic bonds.
- the sulfur-containing material of the present disclosure has a maximum peak intensity (A) within a diffraction angle (2 ⁇ ) range of 23.0° to 23.4° obtained by powder X-ray diffraction using CuK ⁇ radiation.
- the ratio (A/B) to the maximum peak intensity (B) within the range of the diffraction angle (2 ⁇ ) of 24.8° to 25.2° is 1.5 or less (A/B ⁇ 1.5). It satisfies the relationship that there is.
- powder X-ray diffraction using CuK ⁇ rays may be any analytical method as long as it obtains information regarding the structure and phase identification of a crystalline substance.
- the measurement is not particularly limited, but for example, Rigaku: Ultima IV (voltage: 40 kV, current: 40 mA, scan speed: 0.5°/min, sampling: 0.02°, number of integrations: 1 time) , diffraction angle (2 ⁇ ): 10° to 40°).
- the peak intensity ratio (A/B) is 1.4 or less (A/B ⁇ 1 .4), more preferably 1.2 or less (A/B ⁇ 1.2), and even more preferably 1.0 or less (A/B ⁇ 1.0).
- examples of the method of adjusting the peak intensity ratio (A/B) include a method of adjusting the conditions of each step of the method for producing a sulfur-containing material described below.
- a method having a mechanochemical treatment step together with a heating step is used, and the conditions of the mechanochemical treatment in the mechanochemical treatment step are adjusted, and the elemental sulfur in the heat treated material to be subjected to the mechanochemical treatment is Examples include a method of adjusting the content of .
- the peak intensity ratio (A/B) can be reduced by lengthening the treatment time, increasing the rotational speed of the planetary ball mill used in the mechanochemical treatment, or both.
- Total sulfur content The sulfur-containing material of the present disclosure has a total sulfur content of 50% by mass or more.
- total sulfur content refers to the total content of sulfur atoms.
- the total sulfur content in the sulfur-containing material can be calculated from the analysis results using a CHNS analyzer capable of analyzing sulfur and oxygen.
- the total sulfur content in the sulfur-containing material of the present disclosure is preferably 50% by mass to 90% by mass, preferably 51% by mass to 85% by mass, and 52% by mass. It is more preferably from 53% to 75% by weight, even more preferably from 53% to 70% by weight, and even more preferably from 55% to 70% by weight. Most preferably.
- Sulfur-modified compound As the sulfur-modified compound used in the sulfur-containing material of the present disclosure, for example, a compound in which sulfur and an atom in an organic compound are covalently bonded can be used.
- a method for producing such a sulfur-modified compound includes a method of heating elemental sulfur and an organic compound.
- Examples of the organic compounds include acrylic compounds, polyether compounds, pitch compounds, polynuclear aromatic ring compounds, aliphatic hydrocarbon compounds, and thienoacene compounds.
- examples of the sulfur-modified compounds include sulfur-modified acrylic compounds, sulfur-modified polyether compounds, sulfur-modified pitch compounds, sulfur-modified polynuclear aromatic compounds, sulfur-modified aliphatic hydrocarbon compounds, polythienoacene compounds, polysulfide carbon, etc. can be mentioned.
- the sulfur-modified compound is a group consisting of a sulfur-modified acrylic compound, a sulfur-modified polynuclear aromatic compound, and a sulfur-modified polyether compound, from the viewpoint of further increasing the discharge capacity and improving the safety of the battery. It is preferably selected from the following, and even more preferably a sulfur-modified acrylic compound.
- the total sulfur content in the sulfur-modified compound is not particularly limited, but from the viewpoint of further increasing the discharge capacity, it is preferably 30% by mass to 80% by mass, and preferably 40% to 75% by mass. More preferably, the amount is from 45% to 70% by weight.
- the total sulfur content in the sulfur-modified compound can be calculated from the analysis results using a CHNS analyzer capable of analyzing sulfur and oxygen.
- the sulfur-modified compound is preferably contained in 70 parts by mass or more in 100 parts by mass of the sulfur-containing material from the viewpoint of increasing the discharge capacity and improving safety by reducing flammability. , more preferably 75 parts by mass or more, even more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, even more preferably 95 parts by mass or more, and 98 parts by mass. It is even more preferable that at least 1 part is contained.
- the content of the sulfur-modified compound can be measured by a known method.
- the content of sulfur-modified compounds can be determined by thermogravimetrically analyzing the sulfur-containing material. In thermogravimetric analysis, the heating start temperature is 100°C or lower and the heating rate is a constant rate of 10°C/min, and the thermogravimetric loss retention rate is measured until reaching 350°C, and the remaining substances are measured.
- the content of the sulfur-modified compound in the sulfur-containing material can be measured by checking the content ratio (mass%) of the sulfur-containing material.
- Sulfur-modified acrylic compound As the sulfur-modified acrylic compound used in the sulfur-containing material of the present disclosure, for example, a compound in which sulfur and an atom in the acrylic compound are covalently bonded can be used.
- a method for producing such a sulfur-modified acrylic compound includes a method of heating elemental sulfur and an acrylic compound.
- examples of the acrylic compound include polyacrylonitrile compounds and other acrylic compounds.
- examples of the sulfur-modified acrylic compound include sulfur-modified polyacrylonitrile compounds and other sulfur-modified acrylic compounds. From the viewpoint of increasing discharge capacity, the sulfur-modified acrylic compound is preferably a sulfur-modified polyacrylonitrile compound.
- the total sulfur content in the sulfur-modified acrylic compound is not particularly limited, but from the viewpoint of further increasing the discharge capacity, it is preferably 30% by mass to 80% by mass, and 40% to 75% by mass. %, and most preferably 45% to 70% by weight.
- the total sulfur content in the sulfur-modified acrylic compound can be calculated from the analysis results using a CHNS analyzer capable of analyzing sulfur and oxygen.
- Sulfur-modified polyacrylonitrile compound for example, a compound in which sulfur and an atom in the polyacrylonitrile compound are covalently bonded can be used.
- a method for producing such a sulfur-modified polyacrylonitrile compound includes a method of heating elemental sulfur and a polyacrylonitrile compound.
- the sulfur-modified polyacrylonitrile compound in the present disclosure may include one obtained by heating particles in which a hydrocarbon is included in the outer shell made of a polyacrylonitrile compound and elemental sulfur.
- the hydrocarbons included can be saturated or unsaturated aliphatic hydrocarbons having 3 to 8 carbon atoms.
- the polyacrylonitrile compound may contain a structural unit derived from at least one of acrylonitrile and methacrylonitrile. From the viewpoint of increasing discharge capacity, the polyacrylonitrile compound preferably contains at least a structural unit derived from acrylonitrile.
- the content of structural units derived from acrylonitrile and methacrylonitrile is preferably 10 parts by mass or more, and preferably 30 parts by mass or more in 100 parts by mass of the polyacrylonitrile compound. It is more preferable.
- the content of the structural unit derived from acrylonitrile is 10 parts by mass or more in 100 parts by mass of the polyacrylonitrile compound, from the viewpoint of increasing discharge capacity. It is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 80 parts by mass or more, and even more preferably 85 parts by mass or more. More preferably, the amount is 90 parts by mass or more, even more preferably 95 parts by mass or more, and most preferably 100 parts by mass, that is, the polyacrylonitrile compound consists only of structural units derived from acrylonitrile. .
- the content of the structural unit derived from methacrylonitrile is set to 100 parts by mass of the polyacrylonitrile compound. It is preferably 10 parts by mass or more, especially preferably 30 parts by mass or more, especially preferably 30 parts by mass or more and 95 parts by mass or less, especially 30 parts by mass or more and 90 parts by mass or less. It is preferably at most 30 parts by mass and at most 85 parts by mass, particularly preferably at least 30 parts by mass and at most 80 parts by mass.
- the polyacrylonitrile compound may contain structural units derived from monomers other than acrylonitrile and methacrylonitrile.
- monomers include, for example, (meth)acrylate, (meth)acrylic acid ester, (meth)acrylamide, ethylene glycol (meth)acrylate, 1,6-hexanediol (meth)acrylate, neopentyl glycol di(meth) Examples include acrylic monomers such as acrylate and glycerin di(meth)acrylate; and conjugated dienes such as butadiene and isoprene. These other monomers can be used in combination of two or more types.
- “(meth)acrylate” represents either "acrylate” or "methacrylate.”
- (Meth)acrylic” represents either "acrylic” or "methacrylic”.
- the Raman spectrum of the sulfur-containing material of the present disclosure is such that the sulfur-containing material of the present disclosure can exhibit the desired effect.
- the peak exists within the Raman shift range of 1327 cm ⁇ 1 ⁇ 10 cm ⁇ 1 .
- the Raman spectrum of the sulfur-containing material is not only within the above-mentioned range of 1327 cm -1 ⁇ 10 cm -1 but also within the range of 1531 cm -1 ⁇ 10 cm -1 and 939 cm -1 ⁇ .
- Having a peak within at least one of the following ranges: 10 cm -1 , 479 cm -1 ⁇ 10 cm -1 , 377 cm -1 ⁇ 10 cm -1 and 318 cm -1 ⁇ 10 cm -1 Preferably, within the range of 1531 cm -1 ⁇ 10 cm -1 , within the range of 939 cm -1 ⁇ 10 cm -1 , within the range of 479 cm -1 ⁇ 10 cm -1 , within the range of 377 cm -1 ⁇ 10 cm -1 , and More preferably, it has peaks within at least two ranges within the range of 318 cm -1 ⁇ 10 cm -1 , within the range of 1531 cm -1 ⁇ 10 cm -1 , within the range of 939 cm -1 ⁇ 10 cm -1 , It is even more preferable that the peak be within the range of 479 cm ⁇ 1 ⁇ 10 cm ⁇ 1 , within the range of 377 cm ⁇ 1 ⁇ 10 cm ⁇ 1 , and within the range of 318 cm ⁇ 1
- the Raman spectrum of the sulfur-containing material has a peak intensity A1 within the range of 1327 cm -1 ⁇ 10 cm -1 (the maximum peak within the range of 1327 cm -1 ⁇ 10 cm -1 and the peak intensity at 300 cm -1 to 1800 cm -1 ) and the peak intensity B1 within the range 1531 cm -1 ⁇ 10 cm -1 (the maximum peak within the range 1531 cm -1 ⁇ 10 cm -1 and 300 cm -
- the ratio (A1/ B1 ) is preferably from 0.30 to 5.0, more preferably from 0.50 to 4.5. It is preferably from 0.70 to 4.0, even more preferably from 0.80 to 3.5.
- sulfur-modified acrylic compounds are homopolymers of elemental sulfur and other acrylic monomers that do not contain structural units derived from acrylonitrile or methacrylonitrile, or A method of heating the copolymer is mentioned.
- acrylic monomers the same acrylic monomers as described above in "(1-1) Sulfur-modified polyacrylonitrile compound" can be used.
- Sulfur-modified polynuclear aromatic ring compound for example, a compound in which sulfur and an atom in the polynuclear aromatic ring compound are covalently bonded can be used.
- a sulfur-modified polynuclear aromatic ring compound can be produced, for example, by heating a mixture of elemental sulfur and a polynuclear aromatic ring compound as an organic compound.
- polynuclear aromatic ring compounds examples include benzene aromatic ring compounds such as naphthalene, anthracene, tetracene, pentacene, phenanthrene, chrysene, picene, pyrene, benzopyrene, perylene, and coronene, and some of the benzene aromatic ring compounds have five-membered rings. and heteroaromatic compounds containing heteroatoms in which some of these carbon atoms are replaced with sulfur, oxygen, nitrogen, etc.
- these polynuclear aromatic ring compounds include a chain or branched alkyl group having 1 to 12 carbon atoms, an alkoxyl group, a hydroxyl group, a carboxyl group, an amino group, an aminocarbonyl group, an aminothio group, a mercaptothiocarbonylamino group, It may have a substituent such as a carboxyalkylcarbonyl group.
- Sulfur-modified polyether compound As the sulfur-modified polyether compound, the same one described in JP-A-2022-65974 can be used.
- a method for producing a sulfur-containing material includes a sulfur-modified compound, a total sulfur content of 50% by mass or more, and a peak intensity ratio (A/B) of 1.5 by powder X-ray diffraction.
- A/B peak intensity ratio
- a method including a heating step of heating a mixture of elemental sulfur and an organic compound can be mentioned.
- the above manufacturing method may include a mechanochemical treatment step of performing mechanochemical treatment on the heat-treated product after the heating step.
- the heating step in the above manufacturing method is a step of heating a mixture of elemental sulfur and an organic compound. From the viewpoint of increasing the discharge capacity and improving the safety of the battery, the heating step is preferably performed at 200 to 600°C, more preferably from 250 to 500°C, in a non-oxidizing atmosphere.
- the mechanochemical treatment in the above mechanochemical treatment step refers to a treatment that causes a chemical reaction using high energy locally generated by mechanical energy such as friction and compression during the pulverization process of a solid substance.
- the above manufacturing method includes a mechanochemical treatment step. It is presumed that the mechanochemical treatment described above tends to increase the proportion of organic sulfur in the sulfur contained in the sulfur-containing material. More specifically, the mechanochemical treatment described above can cause elemental sulfur contained in the heat-treated material (such as elemental sulfur that did not react in the heating process) to react with a sulfur-modified compound, thereby increasing the proportion of organic sulfur. It is presumed that it is easy to increase.
- mechanical energy such as impact, friction, compression, shearing, etc. can be applied to the heat-treated product, or a combination of these can be applied.
- a device for performing mechanochemical treatment known devices can be used, such as a ball mill, a vibration mill, a planetary ball mill, a cyclone mill, a mixing device such as a media stirring type mill, a ball media mill, a roller mill, a mortar, etc. Examples include a pulverizer, a jet pulverizer that can mainly apply forces such as impact and grinding to the heat-treated material.
- the above-mentioned device is a mixing device such as a ball mill, a vibration mill, a planetary ball mill, a cyclone mill, a media stirring type mill, a ball media mill, a roller mill, a grinding device such as a mortar, etc.
- a mixing device is preferable, a mixing device such as a ball mill, a vibration mill, a planetary ball mill, or a media stirring type mill is more preferable, and a ball mill, a vibration mill, a planetary ball mill, or a cyclone mill is even more preferable.
- the environment in which the mechanochemical treatment is performed may be an oxidizing atmosphere or a non-oxidizing atmosphere, but a non-oxidizing atmosphere is preferable.
- the oxidizing atmosphere refers to an atmosphere containing an oxidizing gas, and includes, for example, an atmosphere containing oxygen, ozone, or nitrogen dioxide.
- the non-oxidizing atmosphere refers to an atmosphere that does not contain oxidizing gas, and includes, for example, an atmosphere consisting of nitrogen or argon.
- the environment in which mechanochemical treatment is performed is preferably a non-oxidizing atmosphere consisting of nitrogen or argon, and a non-oxidizing atmosphere consisting of nitrogen. It is more preferable to use an oxidizing atmosphere.
- the above manufacturing method may include other steps in addition to the heating step and the mechanochemical treatment step.
- the other steps may include a sulfur content adjustment step that is carried out between the heating step and the mechanochemical treatment step and adjusts the elemental sulfur content of the heat-treated product obtained in the heating step.
- the sulfur content adjustment step includes adding elemental sulfur to the heat-treated product to increase the total sulfur content in the heat-treated product used in the mechanochemical treatment step, or removing elemental sulfur from the heat-treated product, The content of elemental sulfur in the heat-treated product used in the mechanochemical treatment step may be reduced.
- the sulfur-containing battery material of the present disclosure contains a sulfur-modified compound, has a total sulfur content of 50% by mass or more, and has a diffraction angle (2 ⁇ ) of 23.0° to 23.0° as determined by powder X-ray diffraction using CuK ⁇ rays.
- the ratio (A/B) of the maximum peak intensity (A) within the range of 23.4° and the maximum peak intensity (B) within the range of the diffraction angle (2 ⁇ ) of 24.8° to 25.2° ) is 1.5 or less (A/B ⁇ 1.5).
- the use of the sulfur-containing battery material in a battery increases the discharge capacity.
- the sulfur-containing battery material has excellent flame retardancy, so it can improve the safety of the battery.
- the use of the sulfur-containing battery material of the present disclosure is not particularly limited, but it can be used for an electrode layer of an electrode in a battery, and is particularly useful as an active material for an electrode layer.
- the sulfur-containing battery material when the sulfur-containing battery material is an active material in an electrode layer of a battery, from the viewpoint of increasing discharge capacity, the sulfur-containing battery material is an active material included in an electrode layer used in a secondary battery. It is preferable that it is, and it is more preferable that it is an active material contained in a cathode active material layer used in a secondary battery, that is, a cathode active material. Note that the battery and electrode layer in the present disclosure will be explained in “C. Electrode” and "D. Battery” below.
- Electrode The electrode according to the present disclosure has an electrode layer containing the sulfur-containing material described in the section "A. Sulfur-containing material" above.
- the discharge capacity can be increased and the safety of the battery can be improved.
- Electrode Layer includes the sulfur-containing material or the sulfur-containing battery material. Furthermore, in this specification, the electrode layer when the above electrode is a positive electrode may be referred to as a "positive electrode active material layer”, and the electrode layer when the above electrode is a negative electrode may be referred to as a "negative electrode active material layer”. It may be written as The thickness of the electrode layer can generally be 1 ⁇ m to 1000 ⁇ m.
- the content of the sulfur-containing material or the sulfur-containing battery material is determined from the viewpoint of effectively functioning as an active material, increasing discharge capacity, and improving battery safety.
- 100 parts by mass of the layer it is preferably 75 parts by mass to 99.5 parts by mass, more preferably 80 parts by mass to 99 parts by mass, and even more preferably 85 parts by mass to 98 parts by mass. .
- the electrode layer contains a sulfur-containing material or a sulfur-containing battery material, but may contain other components as necessary.
- other components include a binder and a conductive additive, and active materials other than sulfur-containing materials and sulfur-containing battery materials, viscosity adjustment, as necessary. It may contain additives, reinforcing agents, antioxidants, etc.
- other components include a binder and a conductive aid, and active materials other than sulfur-containing materials and sulfur-containing battery materials, viscosity adjustment, as necessary. It may contain additives, reinforcing materials, antioxidants, etc.
- binders include styrene-butadiene rubber, butadiene rubber, polyethylene, polypropylene, polyamide, polyamideimide, polyimide, polyacrylonitrile, polyurethane, polyvinylidene fluoride, polytetrafluoroethylene, ethylene-propylene-diene rubber, fluororubber, Styrene-acrylic acid ester copolymer, ethylene-vinyl alcohol copolymer, acrylonitrile butadiene rubber, styrene-isoprene rubber, polymethyl methacrylate, polyacrylate, polyvinyl alcohol, polyvinyl ether, carboxymethylcellulose, sodium carboxymethylcellulose, methylcellulose, cellulose nano Examples include fiber, polyethylene oxide, starch, polyvinylpyrrolidone, polyvinyl chloride, polyacrylic acid, and the like.
- binder Only one type of binder may be used, or two or more types may be used in combination. Among these, water-based binders are preferred, and styrene-butadiene rubber, sodium carboxymethyl cellulose, and polyacrylic acid are more preferred, from the viewpoints of low environmental impact and excellent binding properties.
- the content of the binder in the electrode layer should be 1 part by mass to 30 parts by mass based on 100 parts by mass of the sulfur-containing material or sulfur-containing battery material in the electrode layer, from the viewpoint of further increasing the discharge capacity.
- the amount is preferably 1 part by mass to 20 parts by mass.
- any known conductive aid for electrode layers can be used.
- conductive aids include natural graphite, artificial graphite, carbon black, Ketjen black, acetylene black, channel black, furnace black, lamp black, thermal black, carbon nanotubes, and vapor grown carbon fiber.
- Carbon materials such as VGCF), graphene, fullerene, and needle coke;
- Metal powders such as aluminum powder, nickel powder, and titanium powder;
- Conductive metal oxides such as zinc oxide and titanium oxide; La 2 S 3 , Sm 2 S 3 , Examples include sulfides such as Ce 2 S 3 and TiS 2 .
- One type of conductive aid may be used, or two or more types may be used in combination.
- the average particle diameter of the conductive additive is preferably 0.0001 ⁇ m to 100 ⁇ m, more preferably 0.01 ⁇ m to 50 ⁇ m, from the viewpoint of increasing discharge capacity.
- the "average particle diameter" refers to the 50% particle diameter measured by laser diffraction light scattering method.
- the particle size is a volume-based diameter, and the secondary particle size of the object to be measured is measured.
- the object to be measured is dispersed in a dispersion medium such as water.
- the content of the conductive aid in the electrode layer is 0.1 parts by mass to 50 parts by mass based on 100 parts by mass of the sulfur-containing material or sulfur-containing battery material in the electrode layer, from the viewpoint of increasing discharge capacity. preferably from 0.5 parts by mass to 20 parts by mass, more preferably from 1.0 parts by mass to 10 parts by mass, and from 2.0 parts by mass to 8.0 parts by mass. is most preferred.
- Active materials other than the above-mentioned sulfur-containing materials and sulfur-containing battery materials include materials known as active materials, such as “D. Battery” described below.
- active materials such as “D. Battery” described below.
- the described positive and negative active materials can be used.
- viscosity modifiers those known as viscosity modifiers for electrode layers can be used.
- viscosity modifiers include cellulose polymers such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose, and their ammonium salts and alkali metal salts; (modified) poly(meth)acrylic acid and their ammonium salts and alkali metal salts; (Modified) Polyvinyl alcohols such as polyvinyl alcohol, acrylic acid or a copolymer of acrylic acid and vinyl alcohol, maleic anhydride or a copolymer of maleic acid or fumaric acid and vinyl alcohol; polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone , modified polyacrylic acid, oxidized starch, phosphate starch, casein, various modified starches, cellulose nanofibers, hydrogenated acrylonitrile-butadiene copolymers, and the like. In addition, these may be used as a dispersant.
- reinforcing material those known as reinforcing materials for electrode layers can be used.
- examples of reinforcing materials include various inorganic and organic spherical, plate-like, rod-like, or fibrous fillers.
- antioxidants for electrode layers can be used.
- antioxidants include phenolic compounds, hydroquinone compounds, organic phosphorus compounds, sulfur compounds, phenylenediamine compounds, polymeric phenolic compounds, and the like.
- the method for forming the electrode layer may be any method that can form the electrode layer, for example, an electrode containing the sulfur-containing material or sulfur-containing battery material, other components contained as necessary, and a solvent. Examples include a method of drying and removing the solvent from the coating film after applying the layer-forming composition.
- solvents examples include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, acetonitrile, propionitrile, tetrahydrofuran, 2-methyltetrahydrofuran, Dioxane, 1,3-dioxolane, nitromethane, N-methylpyrrolidone, N,N-dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N,N-dimethylaminopropylamine, polyethylene oxide , tetrahydrofuran, dimethyl sulfoxide, sulfolane, ⁇ -butyrolactone, water, alcohol and the like.
- the amount of solvent used can be adjusted depending on the coating method.
- the amount of solvent used is 20 parts by mass based on 100 parts by mass of the total amount of sulfur-containing material or sulfur-containing battery material, binder, and conductive aid, from the viewpoint of ease of production. It is preferably from 30 parts by weight to 300 parts by weight, more preferably from 30 parts by weight to 200 parts by weight.
- the composition for forming an electrode layer may contain other components than those mentioned above. Other components include, for example, viscosity modifiers, reinforcing agents, antioxidants, and the like.
- the method for preparing the composition for forming an electrode layer is not particularly limited, but includes, for example, a conventional ball mill, sand mill, bead mill, pigment dispersion machine, crusher, ultrasonic dispersion machine, homogenizer, rotation/revolution mixer, and planetary mixer. Examples include methods using a mixer, Filmix, Disper, Jet Paster, etc.
- Application methods are not particularly limited, and include die coater method, comma coater method, curtain coater method, spray coater method, gravure coater method, flexo coater method, knife coater method, doctor blade method, reverse roll method, brush coating method, Various methods such as the dip method can be used.
- the die coater method, doctor blade method, knife coater method, and comma coater method are used from the viewpoint of obtaining a good surface condition of the coating film in accordance with the physical properties such as viscosity and drying properties of the electrode layer forming composition. preferable.
- the dry removal method is not particularly limited, and methods such as heating, reduced pressure, and a combination thereof can be used.
- the heating temperature can be 40°C to 200°C.
- a heating furnace, an infrared heating furnace, a vacuum oven, etc. can be used as a device for heating and reducing pressure.
- the electrode layer may be subjected to a press treatment if necessary.
- the pressing method include a mold pressing method and a roll pressing method.
- Electrode has the above-mentioned electrode layer, but may have other configurations as necessary. Other configurations include a current collector.
- a conductive material such as titanium, titanium alloy, aluminum, aluminum alloy, copper, nickel, stainless steel, nickel-plated steel, or conductive resin is used.
- the surface of these conductive materials may be coated with carbon.
- Examples of the shape of the current collector include foil, plate, mesh, and porous shapes. Among these, from the viewpoint of conductivity and cost, aluminum is preferred, and aluminum foil is more preferred.
- the current collector is in the form of a foil, its thickness can generally be 1 ⁇ m to 100 ⁇ m from the viewpoint of increasing the discharge capacity and making it easy to manufacture.
- Electrodes are not particularly limited, but include batteries.
- batteries include primary batteries and secondary batteries.
- the secondary battery include a lithium ion secondary battery, a sodium ion secondary battery, a potassium ion secondary battery, a magnesium ion secondary battery, a calcium ion secondary battery, and an aluminum ion secondary battery. That is, it can also be a lithium-sulfur secondary battery, a sodium-sulfur secondary battery, a potassium-sulfur secondary battery, a magnesium-sulfur secondary battery, a calcium-sulfur secondary battery, and an aluminum-sulfur secondary battery.
- the electrode of the present disclosure is preferably used as an electrode for a secondary battery, and more preferably as an electrode for a lithium ion secondary battery.
- the electrode of the present disclosure can be used as either a positive electrode or a negative electrode, it is preferable to use it as a positive electrode from the viewpoint of increasing the discharge capacity and being easily manufactured.
- a pre-doping treatment for inserting lithium may be performed in advance.
- the lithium pre-doping method it is sufficient to follow a known method, for example, the electrolytic doping method in which a half cell is assembled using metallic lithium as a counter electrode and lithium is electrochemically doped, or the electrolytic doping method in which metallic lithium foil is pasted on the electrode. Examples include a diffusion doping method in which lithium is left in a liquid electrolyte and doped by utilizing the diffusion of lithium into the electrode.
- a pre-doping treatment to insert sodium may be performed in advance.
- the pre-doping method for sodium a known method may be followed, and for example, the above-mentioned doping method can be used.
- the electrodes may be press-treated if necessary.
- Examples of the press treatment method include a mold press method and a roll press method.
- Electrode The battery of the present disclosure has the electrode described in the section "C. Electrode” above, but may have other configurations as necessary.
- the discharge capacity can be increased, the cycle characteristics can be improved, and safety can also be improved.
- the counter electrode is an electrode used in pair with the above electrode.
- the counter electrode is a negative electrode.
- the counter electrode is a positive electrode.
- the positive electrode and negative electrode used as a counter electrode to the above electrode will be explained separately.
- Negative Electrode As the negative electrode used as the counter electrode, one having a negative electrode active material layer can be used. As the negative electrode active material layer, one containing at least a known active material (hereinafter sometimes referred to as "negative electrode active material”) can be used.
- examples of negative electrode active materials include natural graphite, artificial graphite, non-graphitizable carbon, easily graphitizable carbon, lithium, lithium alloy, silicon, silicon alloy, silicon oxide, tin, tin alloy, Tin oxide, phosphorus, germanium, indium, copper oxide, antimony sulfide, titanium oxide, iron oxide, manganese oxide, cobalt oxide, nickel oxide, lead oxide, ruthenium oxide, tungsten oxide, zinc oxide, as well as LiVO 2 , Li 2 VO 4 , Li 4 Ti 5 O 12 and other complex oxides. Only one type of negative electrode active material may be used, or two or more types may be used in combination.
- negative electrode active materials that do not contain lithium atoms and negative electrode active materials in which lithium atoms are replaced with sodium atoms can be used.
- the negative electrode active material is lithium or a lithium alloy, and sodium or a sodium alloy, the negative electrode active material itself may be used as an electrode without using a current collector.
- potassium, magnesium, calcium, aluminum, zinc, etc. can be used as other negative electrode active materials.
- the negative electrode active material layer contains the negative electrode active material, but may also contain, for example, a binder, a conductive aid, etc., as necessary.
- a binder e.g., a binder, a conductive aid, etc.
- the same binder and conductive aid as those described in the section "C. Electrode” above can be used; Explanation will be omitted.
- positive electrode active material layer one having a positive electrode active material layer can be used.
- positive electrode active material layer one containing at least a known active material (hereinafter sometimes referred to as "positive electrode active material") can be used.
- positive electrode active material include lithium transition metal composite oxides, lithium-containing transition metal phosphate compounds, lithium-containing silicate compounds, and the like. Only one type of positive electrode active material may be used, or two or more types may be used in combination.
- transition metal of the lithium transition metal composite oxide examples include vanadium, titanium, chromium, manganese, iron, cobalt, nickel, copper, and the like.
- Specific examples of lithium transition metal composite oxides include lithium cobalt composite oxides such as LiCoO 2 , lithium nickel composite oxides such as LiNiO 2 , lithium manganese composite oxides such as LiMnO 2 , LiMn 2 O 4 , and Li 2 MnO 3
- Some of the main transition metal atoms in these lithium-transition metal composite oxides include aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, lithium, nickel, copper, zinc, magnesium, gallium, zirconium, etc. Examples include those substituted with other metals.
- transition metal of the lithium-containing transition metal phosphate compound examples include vanadium, titanium, manganese, iron, cobalt, nickel, and the like.
- lithium-containing transition metal phosphate compounds include iron phosphate compounds such as LiFePO 4 and LiMn x Fe 1-x PO 4 (0 ⁇ x ⁇ 1), and iron sulfate compounds such as LiFeSO 4 F.
- cobalt phosphate compounds such as LiCoPO4
- some of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, lithium, nickel, copper
- Examples include those substituted with other metals such as zinc, magnesium, gallium, zirconium, and niobium, and vanadium phosphate compounds such as Li 3 V 2 (PO 4 ) 3 .
- lithium-containing silicate compound examples include Li 2 FeSiO 4 and the like.
- the positive electrode active material layer contains the above-mentioned known active material, but may also contain, for example, a binder, a conductive aid, etc., if necessary.
- a binder e.g., a binder, a conductive aid, etc.
- the same binder and conductive aid as those described in the section "C. Electrode” above can be used, so here Explanation will be omitted.
- Electrolyte is not particularly limited, but any known electrolyte can be used.
- electrolytes include a liquid electrolyte obtained by dissolving a supporting electrolyte in an organic solvent, a polymer gel electrolyte obtained by dissolving a supporting electrolyte in an organic solvent and gelling it with a polymer, and a polymer gel electrolyte obtained by dissolving a supporting electrolyte in an organic solvent and gelling it with a polymer.
- Examples include polymer electrolytes, inorganic solid electrolytes, etc. dispersed in .
- two or more of the above electrolytes may be used in combination.
- the electrolyte is preferably a liquid electrolyte, a polymer electrolyte, or an inorganic solid electrolyte, and more preferably a liquid electrolyte, from the viewpoint of increasing the discharge capacity and facilitating production.
- a conventionally known lithium salt is used as the supporting electrolyte for the liquid electrolyte and the polymer gel electrolyte.
- supporting electrolytes include LiPF6 , LiBF4 , LiAsF6, LiCF3SO3 , LiCF3CO2 , LiN ( CF3SO2 ) 2 , LiN( C2F5SO2 ) 2 , LiN( SO2) .
- LiN(SO 2 F) 2 , LiC(CF 3 SO 2 ) 3 , a derivative of LiCF 3 SO 3 , and a derivative of LiC(CF 3 SO 2 ) 3 may be used. preferable.
- the content of the supporting electrolyte in the liquid electrolyte or polymer gel electrolyte is preferably 0.5 mol/L to 7 mol/L, and 0.8 mol/L to 1.8 mol/L, from the viewpoint of further increasing the discharge capacity. L is more preferable.
- supporting electrolytes used in the polymer electrolyte include, for example, LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , LiN(SO 2 F) 2 , LiC( Examples include CF 3 SO 2 ) 3 , LiB(CF 3 SO 3 ) 4 and LiB(C 2 O 4 ) 2 .
- the inorganic solid electrolyte may be coated with a polymer gel electrolyte. Furthermore, when an inorganic solid electrolyte is used, a polymer gel electrolyte layer may be provided between the inorganic solid electrolyte layer and the electrode.
- a supporting electrolyte in which the lithium atoms in the lithium ion secondary battery described above are replaced with sodium atoms may be used.
- organic solvent used for the liquid electrolyte and the polymer gel electrolyte those commonly used for liquid electrolytes can be used.
- organic solvents include saturated cyclic carbonate compounds, saturated cyclic ester compounds, sulfoxide compounds, sulfone compounds, amide compounds, saturated chain carbonate compounds, chain ether compounds, cyclic ether compounds, saturated chain ester compounds, etc. It will be done.
- saturated cyclic carbonate compounds, saturated cyclic ester compounds, sulfoxide compounds, sulfone compounds, and amide compounds are preferred from the viewpoint that they have a high dielectric constant and play a role in increasing the dielectric constant of the electrolyte, thereby further increasing the discharge capacity.
- saturated cyclic carbonate compounds are more preferred.
- saturated chain carbonate compounds which can lower the viscosity of the electrolyte and increase the mobility of electrolyte ions to improve battery characteristics such as output density, are preferred.
- Chain ether compounds, cyclic ether compounds and saturated chain ester compounds are preferred, and saturated chain carbonate compounds are more preferred.
- saturated cyclic carbonate compounds include ethylene carbonate, fluoroethylene carbonate, 1,2-propylene carbonate, 1,3-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, 1,1-dimethyl Examples include ethylene carbonate.
- saturated cyclic ester compounds examples include ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -caprolactone, ⁇ -hexanolactone, ⁇ -octanolactone, and the like.
- sulfoxide compounds include dimethyl sulfoxide, diethyl sulfoxide, dipropylsulfoxide, diphenyl sulfoxide, thiophene, and the like.
- sulfone compounds include dimethylsulfone, diethylsulfone, dipropylsulfone, diphenylsulfone, sulfolane (also referred to as tetramethylenesulfone), 3-methylsulfolane, 3,4-dimethylsulfolane, 3,4-diphenymethylsulfolane. , sulfolene, 3-methylsulfolene, 3-ethylsulfolene, 3-bromomethylsulfolene, and the like. Among these, sulfolane and tetramethylsulfolane are preferred from the viewpoint of further increasing discharge capacity.
- amide compounds examples include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and the like.
- saturated chain carbonate compounds examples include dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, ethyl butyl carbonate, methyl-t-butyl carbonate, diisopropyl carbonate, t-butylpropyl carbonate, and the like.
- chain ether compounds and cyclic ether compounds examples include dimethoxyethane, ethoxymethoxyethane, diethoxyethane, tetrahydrofuran, dioxolane, dioxane, 1,2-bis(methoxycarbonyloxy)ethane, 1,2-bis(ethoxy carbonyloxy)ethane, 1,2-bis(ethoxycarbonyloxy)propane, ethylene glycol bis(trifluoroethyl) ether, propylene glycol bis(trifluoroethyl) ether, ethylene glycol bis(trifluoromethyl) ether, diethylene glycol bis( (trifluoroethyl) ether, glymes, etc.
- dioxolane is preferred from the viewpoint of further increasing discharge capacity.
- saturated chain ester compounds examples include monoester compounds and diester compounds in which the total number of carbon atoms in the molecule is 2 to 8.
- Specific examples of saturated chain ester compounds include methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, and trimethylmethyl acetate.
- methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, methyl propionate, and ethyl propionate are preferred from the viewpoint of further increasing discharge capacity.
- organic solvents examples include acetonitrile, propionitrile, nitromethane, derivatives thereof, and various ionic liquids.
- polymers used in the polymer gel electrolyte include polyethylene oxide, polypropylene oxide, polyvinyl chloride, polyacrylonitrile, polymethyl methacrylate, polyethylene, polyvinylidene fluoride, polyhexafluoropropylene, and the like.
- polymers used in the polymer gel electrolyte and the gelling method There are no particular limitations on the blending ratio of polymers in the polymer gel electrolyte and the gelling method, and any blending ratio and gelling method known in the technical field may be employed.
- polymers used in the polymer electrolyte include polyethylene oxide, polypropylene oxide, polystyrene sulfonic acid, and polyvinylidene fluoride. There are no particular restrictions on the blending ratio of the polymers in the polymer electrolyte and the method of compositing, and any known blending ratio and known compositing method in this technical field may be employed.
- the electrolyte may contain other known additives, such as an electrode film forming agent, an antioxidant, a flame retardant, an overcharge inhibitor, etc., in order to improve battery life, safety, etc.
- the content of other additives is usually 0.01 parts by mass to 10 parts by mass, and 0.1 parts by mass to 5 parts by mass, based on 100 parts by mass of the entire electrolyte. It is preferable that
- the separator mentioned above is not particularly limited as long as it can transmit lithium ions and prevent contact between the positive electrode and the negative electrode, but for example, a microporous polymer film can be used. Or non-woven fabric etc. can be used.
- films include polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, and polyethers such as polyethylene oxide and polypropylene oxide.
- various celluloses such as carboxymethyl cellulose and hydroxypropyl cellulose, polymer compounds and derivatives thereof mainly composed of poly(meth)acrylic acid and its various esters, copolymers and mixtures of these, etc. can be mentioned.
- These films may be coated with ceramic materials such as alumina or silica, magnesium oxide, aramid resin, or polyvinylidene fluoride.
- These films may be used alone or may be used as a multilayer film by stacking the films. Furthermore, various additives may be used in these films, and their types and contents are not particularly limited. Among these films, films made of polyethylene, polypropylene, polyvinylidene fluoride, or polysulfone are preferred from the viewpoint of further increasing the discharge capacity of the secondary battery. Note that if the electrolyte is a polymer electrolyte or an inorganic solid electrolyte, the separator may not be included.
- the shape of the battery is not particularly limited, and can be made into various shapes such as a coin shape, a cylindrical shape, a square shape, and a laminate shape.
- a laminate film or a metal container can be used as the exterior material of the battery.
- the thickness of the exterior material is usually 0.5 mm or less, and preferably 0.3 mm or less.
- the shape of the exterior material can be flat (thin), rectangular, cylindrical, coin-shaped, button-shaped, etc.
- the laminate film a multilayer film having a metal layer between resin films can also be used.
- the metal layer is preferably aluminum foil or aluminum alloy foil for weight reduction.
- a polymer material such as polypropylene, polyethylene, nylon, or polyethylene terephthalate can be used.
- the laminate film can be formed into the shape of an exterior member by sealing it by heat fusion.
- the metal container can be made of, for example, stainless steel, aluminum, or an aluminum alloy.
- As the aluminum alloy an alloy containing elements such as magnesium, zinc, and silicon is preferable.
- Battery The battery of the present disclosure may be either a primary battery or a secondary battery, but is preferably a secondary battery. The reason is that it is useful as a vehicle battery.
- [1] Contains a sulfur-modified compound, has a total sulfur content of 50% by mass or more, and has a diffraction angle (2 ⁇ ) in the range of 23.0° to 23.4°, obtained by powder X-ray diffraction using CuK ⁇ rays.
- the ratio (A/B) of the maximum peak intensity (A) within the range to the maximum peak intensity (B) within the range of the diffraction angle (2 ⁇ ) of 24.8° to 25.2° is 1.5 or less
- the sulfur-containing material according to [1], wherein the sulfur-modified compound is a sulfur-modified acrylic compound.
- [3] Contains a sulfur-modified compound, has a total sulfur content of 50% by mass or more, and has a diffraction angle (2 ⁇ ) in the range of 23.0° to 23.4°, obtained by powder X-ray diffraction using CuK ⁇ rays.
- the ratio (A/B) of the maximum peak intensity (A) within the range to the maximum peak intensity (B) within the range of the diffraction angle (2 ⁇ ) of 24.8° to 25.2° is 1.5 or less
- the sulfur-containing battery material according to [3], wherein the sulfur-modified compound is a sulfur-modified acrylic compound.
- Example 1 Production of sulfur-containing material A First, a heating step was performed in accordance with the production example of JP-A-2013-054957. That is, a mixture of 10 parts by mass of polyacrylonitrile powder (manufactured by Sigma-Aldrich, average particle size 200 ⁇ m) and 30 parts by mass of elemental sulfur (manufactured by Sigma-Aldrich, average particle size 200 ⁇ m) (hereinafter sometimes referred to as raw material PAN mixture) ) was placed in a bottomed cylindrical glass tube with an outer diameter of 45 mm and a length of 120 mm, and a silicone stopper having a gas inlet tube and a gas outlet tube was attached to the opening of the glass tube.
- PAN mixture a silicone stopper having a gas inlet tube and a gas outlet tube was attached to the opening of the glass tube.
- Heat-treated product 1 was obtained. Note that the sulfur vapor was condensed at the top or lid of the glass tube and refluxed.
- the obtained heat-treated product 1 was placed in a glass tube oven at 260° C. and heated under reduced pressure at 20 hPa for 3.0 hours to remove elemental sulfur, thereby obtaining a heat-treated product 2.
- the total sulfur content of heat-treated product 2 was 49% by mass, and the content of elemental sulfur contained in heat-treated product 2 was 0% by mass.
- Example 2 Production of sulfur-containing material B A heat-treated product 4 was obtained in the same manner as in Example 1, except that the reduced pressure heating time for the heat-treated product 1 was changed to 1.5 hours. The total sulfur content of the heat-treated product 4 was 60% by mass, and the content of elemental sulfur contained in the heat-treated product 4 was 11% by mass. Thereafter, the heat-treated product 4 was subjected to mechanochemical treatment using a planetary ball mill (manufactured by Fritsch, P-7 Classic Line) under an argon atmosphere at a rotation speed of 1600 rpm and a treatment time of 300 minutes. A sulfur-containing material B was obtained.
- a planetary ball mill manufactured by Fritsch, P-7 Classic Line
- Example 3 Production of Sulfur-Containing Material C After obtaining heat-treated product 2 in the same manner as in Example 1, 11 parts by mass of elemental sulfur (Sigma-Aldrich, average particle size 200 ⁇ m) was added to 100 parts by mass of heat-treated product 2 to prepare heat-treated product 5. Heat-treated product 5 was subjected to mechanochemical treatment using a planetary ball mill (Fritsch, P-7 Classic Line) under an argon atmosphere at a rotation speed of 1600 rpm for a treatment time of 100 minutes to obtain sulfur-containing material C.
- elemental sulfur Sigma-Aldrich, average particle size 200 ⁇ m
- Total sulfur content The total sulfur content (mass%) in the sulfur-containing materials obtained in Examples and Comparative Examples was calculated from the analysis results using a CHNS analyzer (manufactured by Elementar Analysensysteme GmbH, model: varioMICROcube) that can analyze sulfur and oxygen.
- the temperature of the combustion tube was 1150°C
- the temperature of the reduction tube was 850°C
- a tin boat was used as the sample container. The results are shown in Tables 1 to 3.
- Electrolyte solution 1 was prepared by dissolving LiPF 6 at a concentration of 1.0 mol/L in a mixed solvent consisting of 50% by volume of fluoroethylene carbonate and 50% by volume of diethyl carbonate.
- Electrolyte solution 2 was prepared by dissolving LiN(CF 3 SO 2 ) 2 at a concentration of 1.0 mol/L in a mixed solvent consisting of 50 volume % dimethoxyethane and 50 volume % dioxolane.
- the measurement results of powder X-ray diffraction of sulfur-containing material A are shown in FIG.
- the measurement results of powder X-ray diffraction of sulfur-containing material b are shown in FIG.
- the sulfur-containing material of the example has high flame retardancy and can improve the safety of the battery. It was also found that the battery using the sulfur-containing material of the example had a large discharge capacity. Furthermore, it was found that the battery using the sulfur-containing material of the example had an improved capacity retention rate, and therefore had excellent cycle characteristics.
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Abstract
Description
まず、本開示の硫黄含有材料について説明する。
本開示の硫黄含有材料は、硫黄変性化合物を含み、硫黄全含量が50質量%以上であり、CuKα線を用いた粉末X線回折で得られる、回折角度(2θ)が23.0°~23.4°の範囲内の最大のピーク強度(A)と、回折角度(2θ)が24.8°~25.2°の範囲内の最大のピーク強度(B)との比(A/B)が1.5以下(A/B≦1.5)である。
本開示において、単体硫黄とは、硫黄変性化合物と安定的な相互作用を形成していない硫黄とすることができる。具体的には、単体硫黄としては、特に限定されないが、S8構造を有するα硫黄、β硫黄及びγ硫黄が挙げられる。
理論容量が1670mAh/g程度である硫黄全含量が50質量%以上であることにより、放電容量が増大する。また、粉末X線回折で得られる所定のピーク強度の関係を満たすことにより、硫黄含有材料に含有される硫黄は、有機硫黄の割合が大きいものと推測される。
ここで、有機硫黄とは、単体硫黄とは異なるものであり、例えば、硫黄変性化合物内で安定的な相互作用を形成している硫黄又は硫黄変性化合物と安定的な相互作用を形成している硫黄とすることができる。そのような有機硫黄の割合が大きい結果、例えば、充放電時において、硫黄とリチウムとの反応性の向上、さらには多硫化リチウムの溶出や副反応を抑制し、効果的に放電容量の増大を図ることができると共に、サイクル特性の向上の効果を発揮することが可能となる。更に、硫黄含有材料に含有される硫黄に占める単体硫黄の割合が小さいことで、可燃性を抑制し、電池の安全性が向上する効果を同時に発揮することが可能となる。
有機硫黄としては、安定的な相互作用を形成する1つの硫黄原子からなるものであってもよく、ジスルフィド、トリスルフィド等複数の硫黄原子であってもよい。硫黄原子が複数の場合にはその一部の硫黄原子が相互作用していれば良く、例えば、直鎖状の硫黄である場合は、少なくとも片方の末端の硫黄が安定的な相互作用を形成しているものであってもよい。
また、安定的な相互作用としては、CuKα線を用いた粉末X線回折において、単体硫黄に起因する回折ピークを生じないもの、より具体的には、23.2°付近(例えば、23.0°~23.4°の範囲内)等の回折角度(2θ)で強い回折ピークが生じないものが挙げられ、例えば、共有結合又はイオン結合等が挙げられる。
本開示の硫黄含有材料は、CuKα線を用いた粉末X線回折で得られる、回折角度(2θ)が23.0°~23.4°の範囲内の最大のピーク強度(A)と、回折角度(2θ)が24.8°~25.2°の範囲内の最大のピーク強度(B)との比(A/B)が1.5以下(A/B≦1.5)であるという関係を満たすものである。
また、「回折角度(2θ)が24.8°~25.2°の範囲内の最大のピーク強度(B)」とは、24.8°~25.2°の範囲にて測定される回折強度(cps)の最大値I(B-max)と20.0°~40.0°の範囲にて測定される回折強度(cps)の最小値I(min)との差を表す。つまり、(B)=I(B-max)-I(min)である。
本開示の硫黄含有材料は、硫黄全含量が50質量%以上である。ここで、「硫黄全含量」とは、硫黄原子の全含量を示すものである。硫黄含有材料中の硫黄全含量は、硫黄及び酸素を分析可能なCHNS分析装置を用いた分析結果から算出できる。
本開示の硫黄含有材料に用いられる硫黄変性化合物としては、例えば、硫黄と有機化合物中の原子とが共有結合した化合物を用いることができる。このような硫黄変性化合物の製造方法としては、単体硫黄と有機化合物とを加熱する方法が挙げられる。
すなわち、上記硫黄変性化合物としては、例えば、硫黄変性アクリル系化合物、硫黄変性ポリエーテル化合物、硫黄変性ピッチ化合物、硫黄変性多核芳香環化合物、硫黄変性脂肪族炭化水素化合物、ポリチエノアセン化合物、ポリ硫化カーボン等が挙げられる。
本開示の硫黄含有材料に用いられる硫黄変性アクリル系化合物としては、例えば、硫黄とアクリル系化合物中の原子とが共有結合した化合物を用いることができる。このような硫黄変性アクリル系化合物の製造方法としては、単体硫黄とアクリル系化合物とを加熱する方法が挙げられる。
本開示の硫黄変性ポリアクリロニトリル系化合物は、例えば、硫黄とポリアクリロニトリル系化合物中の原子とが共有結合した化合物を用いることができる。このような硫黄変性ポリアクリロニトリル系化合物の製造方法としては、単体硫黄とポリアクリロニトリル系化合物とを加熱する方法が挙げられる。また、本開示における硫黄変性ポリアクリロニトリル系化合物は、ポリアクリロニトリル系化合物からなる外殻に炭化水素を包含させた粒子と単体硫黄とを加熱する方法で得られたものを含んでいてもよい。包含する炭化水素は、炭素数3~8の飽和又は不飽和の脂肪族炭化水素とすることができる。
ここで、「(メタ)アクリレート」は、「アクリレート」及び「メタクリレート」の何れかを表す。「(メタ)アクリル」は、「アクリル」及び「メタクリル」の何れかを表す。
本開示において、その他の硫黄変性アクリル系化合物は、単体硫黄とアクリロニトリル又はメタクリロニトリルに由来する構成単位を含まない他のアクリル系モノマーのホモポリマー又はコポリマーとを加熱する方法が挙げられる。他のアクリル系モノマーとしては、上記「(1-1)硫黄変性ポリアクリロニトリル系化合物」における他のアクリル系モノマーとして記載したものと同じものを使用することができる。
上記硫黄変性多核芳香環化合物は、例えば、硫黄と多核芳香環化合物中の原子とが共有結合した化合物を用いることができる。硫黄変性多核芳香環化合物は、例えば、単体硫黄と、有機化合物としての多核芳香環化合物との混合物を加熱することで製造することができる。多核芳香環化合物の例としては、ナフタレン、アントラセン、テトラセン、ペンタセン、フェナントレン、クリセン、ピセン、ピレン、ベンゾピレン、ペリレン、コロネン等のベンゼン系芳香環化合物、ベンゼン系芳香環化合物の一部が5員環となった芳香族環化合物、又はこれらの炭素原子の一部が硫黄、酸素、窒素等に置き換わったヘテロ原子含有複素芳香環化合物が挙げられる。更に、これらの多核芳香環化合物は、炭素原子数1以上12以下の鎖状若しくは分岐状アルキル基、アルコキシル基、水酸基、カルボキシル基、アミノ基、アミノカルボニル基、アミノチオ基、メルカプトチオカルボニルアミノ基、カルボキシアルキルカルボニル基等の置換基を有してもよい。
上記硫黄変性ポリエーテル化合物としては、特開2022-65974号公報に記載したものと同じものを使用することができる。
本開示において、硫黄含有材料の製造方法としては、硫黄変性化合物を含み、硫黄全含量が50質量%以上であり且つ粉末X線回折によるピーク強度比(A/B)が1.5以下という関係を満たす材料が得られる方法であれば、特に限定されるものではないが、単体硫黄と有機化合物との混合物を加熱する加熱工程を有する方法を挙げることができる。上記製造方法が、上記加熱工程後の加熱処理物に対して、メカノケミカル処理するメカノケミカル処理工程を有する方法であってもよい。
次に、本開示の硫黄含有電池材料について説明する。
本開示の硫黄含有電池材料は、硫黄変性化合物を含み、硫黄全含量が50質量%以上であり、CuKα線を用いた粉末X線回折で得られる、回折角度(2θ)が23.0°~23.4°の範囲内の最大のピーク強度(A)と、回折角度(2θ)が24.8°~25.2°の範囲内の最大のピーク強度(B)との比(A/B)が1.5以下(A/B≦1.5)である。
なお、本開示における電池及び電極層については、下記「C.電極」及び「D.電池」において説明する。
本開示における電極は、上記「A.硫黄含有材料」の項に記載の硫黄含有材料を含む電極層を有するものである。
本開示において、「電極層」とは、上記硫黄含有材料又は上記硫黄含有電池材料を含むものである。また、本明細書では、上記電極が正極である場合の電極層を「正極活物質層」と記載することがあり、また、上記電極が負極である場合の電極層を「負極活物質層」と記載することがある。電極層の厚さは、通常1μm~1000μmとすることができる。
上記電極層が、正極活物質層として用いられる場合、その他の成分としては、結着剤及び導電助剤が挙げられ、必要に応じて硫黄含有材料及び硫黄含有電池材料以外の活物質、粘度調整剤、補強材、酸化防止剤等を含有していてもよい。
上記電極層が、負極活物質層として用いられる場合、その他の成分としては、結着剤及び導電助剤が挙げられ、必要に応じて硫黄含有材料及び硫黄含有電池材料以外の活物質、粘度調整剤、補強材、酸化防止剤等を含有していてもよい。
電極層形成用組成物は、上記以外の他の成分を含んでいる場合がある。他の成分としては、例えば、粘度調整剤、補強材、酸化防止剤等が挙げられる。
本開示の電極は、上記電極層を有するものであるが、必要に応じてその他の構成を有するものであってもよい。その他の構成としては、集電体が挙げられる。
1.電極
本開示の電池は、上記「C.電極」の項に記載の電極を有するものであるが、必要に応じてその他の構成を有するものであってもよい。
その他の構成としては、上記電極と対で用いられる対電極、電解質、セパレータ等が挙げられる。
上記対電極は、上記電極と対で用いられる電極である。上記電極が正極である場合、対電極は負極である。上記電極が負極である場合、対電極は正極である。
以下、上記電極の対電極として用いられる正極及び負極について分けて説明する。
上記対電極として用いられる負極としては、負極活物質層を有するものを用いることができる。
上記負極活物質層としては、少なくとも公知の活物質(以下、「負極活物質」と記載することがある)を含むものを用いることができる。
上記負極活物質層に用いられる結着剤及び導電助剤については、上記「C.電極」の項に記載の結着剤及び導電助剤と同様のものを用いることができるため、ここでの説明は省略する。
上記対電極として用いられる正極としては、正極活物質層を有するものを用いることができる。
上記正極活物質層としては、少なくとも公知の活物質(以下、「正極活物質」と記載することがある)を含むものを用いることができる。
上記正極活物質としては、例えば、リチウム遷移金属複合酸化物、リチウム含有遷移金属リン酸化合物、リチウム含有ケイ酸塩化合物等が挙げられる。正極活物質は、1種のみを使用してもよいし、2種以上を組み合わせて使用してもよい。
上記正極活物質層に用いられる結着剤及び導電助剤については、上記「C.電極」の項に記載の結着剤及び導電助剤と同様のものを用いることができるため、ここでの説明は省略する。
上記電解質としては、特に限定されるものではないが、公知の電解質を使用することができる。電解質の例としては、支持電解質を有機溶媒に溶解して得られる液体電解質、支持電解質を有機溶媒に溶解し高分子でゲル化した高分子ゲル電解質、有機溶媒を含まず、支持電解質を高分子に分散させた高分子電解質、無機固体電解質等が挙げられる。また、上記電解質を2種類以上組み合わせて用いてもよい。
本開示においては、放電容量がより増大し且つ製造が容易であるという観点から、電解質が、液体電解質、高分子電解質又は無機固体電解質であることが好ましく、液体電解質であることがより好ましい。
上記セパレータとしては、リチウムイオンを透過し、正極と負極との接触を防ぐことができるものであればよく、特に限定されるものでないが、例えば、高分子の微多孔性のフィルム又は不織布等を使用できる。フィルムの例としては、ポリエチレン、ポリプロピレン、ポリフッ化ビニリデン、ポリ塩化ビニリデン、ポリアクリロニトリル、ポリアクリルアミド、ポリテトラフルオロエチレン、ポリスルホン、ポリエーテルスルホン、ポリカーボネート、ポリアミド、ポリイミド、ポリエチレンオキシドやポリプロピレンオキシド等のポリエーテル類、カルボキシメチルセルロースやヒドロキシプロピルセルロース等の種々のセルロース類、ポリ(メタ)アクリル酸及びその種々のエステル類等を主体とする高分子化合物やその誘導体、これらの共重合体や混合物からなるもの等が挙げられる。これらのフィルムは、アルミナやシリカなどのセラミック材料や、酸化マグネシウム、アラミド樹脂、ポリフッ化ビニリデンでコートされていてもよい。
なお、電解質が高分子電解質や無機固体電解質の場合には、セパレータを含まなくてもよい。
本開示において、電池の形状は特に制限を受けず、コイン型、円筒型、角型、ラミネート型等、種々の形状とすることができる。
金属製容器は、例えば、ステンレス、アルミニウム又はアルミニウム合金等から形成することができる。アルミニウム合金としては、マグネシウム、亜鉛、ケイ素などの元素を含む合金が好ましい。アルミニウム又はアルミニウム合金において、鉄、銅、ニッケル、クロム等の遷移金属の含有量を1質量%以下にすることで、高温環境下での長期信頼性及び放熱性を飛躍的に向上させることができる。
本開示の電池は、一次電池及び二次電池のいずれであってもよいが、二次電池であることが好ましい。その理由は、車載用電池として有用であるためである。
本開示においては、以下の態様が挙げられる。
[1]硫黄変性化合物を含み、硫黄全含量が50質量%以上であり、CuKα線を用いた粉末X線回折で得られる、回折角度(2θ)が23.0°~23.4°の範囲内の最大のピーク強度(A)と、回折角度(2θ)が24.8°~25.2°の範囲内の最大のピーク強度(B)との比(A/B)が1.5以下(A/B≦1.5)であることを特徴とする硫黄含有材料。
[2]硫黄変性化合物が硫黄変性アクリル系化合物であることを特徴とする[1]に記載の硫黄含有材料。
[3]硫黄変性化合物を含み、硫黄全含量が50質量%以上であり、CuKα線を用いた粉末X線回折で得られる、回折角度(2θ)が23.0°~23.4°の範囲内の最大のピーク強度(A)と、回折角度(2θ)が24.8°~25.2°の範囲内の最大のピーク強度(B)との比(A/B)が1.5以下(A/B≦1.5)であることを特徴とする硫黄含有電池材料。
[4]硫黄変性化合物が硫黄変性アクリル系化合物であることを特徴とする[3]に記載の硫黄含有電池材料。
[5][1]もしくは[2]に記載の硫黄含有材料又は[3]もしくは[4]に記載の硫黄含有電池材料を含む電極層を有する電極。
[6][5]に記載の電極を有する電池。
[7]電極が正極である[6]に記載の電池。
[8]負極がリチウムである[7]に記載の電池。
先ず、特開2013-054957号公報の製造例に準じた方法で加熱工程を行った。すなわち、ポリアクリロニトリル粉末(シグマアルドリッチ製、平均粒径200μm)10質量部及び単体硫黄(シグマアルドリッチ製、平均粒径200μm)30質量部を混合した混合物(以後、原料PAN混合物と記載することがある)20gを外径45mm、長さ120mmの有底円筒状ガラス管に収容した後、ガラス管の開口部にガス導入管及びガス排出管を有するシリコーン栓を取り付けた。ガラス管内部の空気を窒素で置換した後、ガラス管の下部をルツボ型電気炉に挿入し、ガス導入管から窒素を導入して発生する硫化水素を除去しながら400℃で1時間加熱し、加熱処理物1を得た。なお、硫黄蒸気はガラス管の上部又は蓋部で凝結して還流させた。得られた加熱処理物1を260℃のガラスチューブオーブンに入れ、減圧し20hPaで3.0時間加熱して単体硫黄を除去し、加熱処理物2を得た。
加熱処理物2の硫黄全含量は49質量%であり、加熱処理物2に含まれる単体硫黄の含有量は0質量%であった。
その後、メカノケミカル処理工程を行った。表1に示す粉末X線回折のピーク強度比(A/B)となるように、100質量部の加熱処理物2に対して単体硫黄(シグマアルドリッチ製、平均粒径200μm)30質量部を加えた加熱処理物3を準備し、加熱処理物3を、自転回転数を1600rpm、処理時間を300分、アルゴン雰囲気下、遊星型ボールミル(フリッチュ社製、P-7クラシックライン)を用いてメカノケミカル処理を行い、硫黄含有材料Aを得た。
硫黄含有材料Aのラマンスペクトルの測定結果を図1に示す。ピーク強度A1とピーク強度B1との比率(A1/B1)は110.8/56.1=1.98と求められた。
加熱処理物1に対する減圧加熱時間を1.5時間に変えたこと以外は実施例1と同様にして加熱処理物4を得た。
加熱処理物4の硫黄全含量は60質量%であり、加熱処理物4に含まれる単体硫黄の含有量は11質量%であった。
その後、加熱処理物4に対して、アルゴン雰囲気下、自転回転数を1600rpm、処理時間を300分、アルゴン雰囲気下、遊星型ボールミル(フリッチュ社製、P-7クラシックライン)を用いてメカノケミカル処理を行い、硫黄含有材料Bを得た。
実施例1と同様にして加熱処理物2を得た後、100質量部の加熱処理物2に対して単体硫黄(シグマアルドリッチ製、平均粒径200μm)を11質量部加えた加熱処理物5を準備し、加熱処理物5を、自転回転数を1600rpm、処理時間を100分、アルゴン雰囲気下、遊星型ボールミル(フリッチュ社製、P-7クラシックライン)を用いてメカノケミカル処理を行い、硫黄含有材料Cを得た。
加熱処理物1を260℃のガラスチューブオーブンに入れ、減圧し20hPaで3.0時間加熱して単体硫黄を除去し、硫黄含有材料aを得た。
加熱処理物1に対する減圧加熱時間を1.5時間に変えたこと以外は比較例1と同様にして硫黄含有材料bを得た。
実施例1と同様にして加熱処理物2を得た後、表1に示す粉末X線回折のピーク強度比(A/B)となるように、100質量部の加熱処理物2に対して単体硫黄(シグマアルドリッチ製、平均粒径200μm)160量部を加えた加熱処理物6を準備し、加熱処理物6を、自転回転数を2000rpm、処理時間を400分間、アルゴン雰囲気下、遊星型ボールミル(フリッチュ社製、P-7クラシックライン)を用いてメカノケミカル処理を行い、硫黄含有材料cを得た。
加熱処理物1に対する減圧加熱時間を2.0時間に変えたこと以外は比較例1と同様にして硫黄含有材料dを得た。
実施例及び比較例で得られた硫黄含有材料における硫黄全含量(質量%)を、硫黄及び酸素が分析可能なCHNS分析装置(Elementar Analysensysteme GmbH製 型式:varioMICROcube)を用いた分析結果から算出した。なお、燃焼管温度は1150℃、還元管温度は850℃とし、サンプル容器は錫ボートを使用した。結果を表1~3に示す。
実施例及び比較例で得られた硫黄含有材料について、粉末X線回折装置(リガク社製、UltimaIV)を用いてX線回折分析を行った。測定条件は、CuKα線、電圧:40kV、電流:40mA、スキャン速度:0.5°/分、サンプリング:0.02°、積算回数:1回、回折角度(2θ):10°~40°とした。
X線回折で得られた回折パターンで得られる、22.8°~23.2°の回折角度(2θ)の範囲内の最大のピーク強度(A)と、24.8°~25.2°の回折角度(2θ)の範囲内の最大のピーク強度(B)との比を算出した。結果を表1~3に示す。
実施例及び比較例で得られた硫黄含有材料4gを秤量し、断熱板上に半球状に堆積するように置いた。拡散炎の長さが約7mmとなるように調節した着火器具を用いて、炎と硫黄含有材料との接触面積が2cm2、接触角度が約30°となるように、炎と硫黄含有材料とを10秒間接触させた。
このとき、10秒間接触させて着火又は燃焼しないものを「不着火」とし、着火又は燃焼が生じたものを「着火」とした。不着火であるものは、難燃性が高いと判断することができる。結果を表1~3に示す。
実施例及び比較例で得られた硫黄含有材料を用いて二次電池を作製した。
正極活物質層の活物質としての硫黄含有材料90.0質量部、導電助剤としてのアセチレンブラック(デンカ製)5.0質量部、結着剤としてのスチレン-ブタジエンゴム(水分散液、日本ゼオン製)3.0質量部及びカルボキシメチルセルロースナトリウム(ダイセルファインケム製)2.0質量部、並びに溶媒としての水120質量部を、自転・公転ミキサーを用いて混合し、電極層形成用組成物を調製した。
この電極層形成用組成物を、ドクターブレード法により、集電体としてのカーボンコートされたアルミニウム箔(厚さ20μm)上に塗布し、90℃で1時間乾燥させた。その後、この電極を所定の大きさに切断し、130℃で2時間真空乾燥を行い、円盤状の正極を調製した。
厚さ500μmのリチウム金属を所定の大きさに切断し、円盤状の負極を調製した。
フルオロエチレンカーボネート50体積%及びジエチルカーボネート50体積%からなる混合溶媒に、LiPF6を1.0mol/Lの濃度で溶解し電解質溶液1を調製した。
ジメトキシエタン50体積%及びジオキソラン50体積%からなる混合溶媒に、LiN(CF3SO2)2を1.0mol/Lの濃度で溶解し電解質溶液2を調製した。
先に調製した正極及び負極で、セパレータとしてのガラスフィルターを挟んでケース内に保持した。その後、先に調製した電解質溶液1をケース内に注入し、ケースを密閉し、封止して、二次電池(φ20mm、厚さ3.2mmのコイン型)をそれぞれ作製した。なお、「(4)電池の作製」の作製手順は露点が-70℃の雰囲気にて行った。
電解質溶液1を電解質溶液2に変えたこと以外は上記と同様にして二次電池をそれぞれ作製した。
上記で作製した二次電池を、25℃の恒温槽に入れ、充電終止電圧を3.0V、放電終止電圧を1.0Vとし、充電レート0.1C、放電レート0.1Cの充放電を100サイクル行い、10サイクル目及び100サイクル目の放電容量(mAh/g)を測定した。10サイクル目の放電容量(mAh/g)の結果を表1~3に示す。なお、本開示において、放電容量(mAh/g)における「g」は正極活物質層における活物質の質量を示す。
また、10サイクル目の放電容量に対する100サイクル目の放電容量の割合を容量維持率(%)とし、サイクル特性について評価した。結果を表1~3に示す。
(1)電池の作製
電極活物質としての硫黄含有材料50.0質量部、導電助剤としてのアセチレンブラック(デンカ製)5.0質量部、及び固体電解質としてのLPS(Li2S:P2S5=75:25(モル比))45.0質量部をボールミルを用いて混合し、プレス処理により成形し、直径10mmの円形の正極活物質層を調製した。
次に、LPSをプレス処理により成形し、直径10mmの円形の固体電解質層を調製した。
その後、SUS箔/正極活物質層/固体電解質層/インジウム-リチウム合金/SUS箔の順で積層し、荷重20kNでプレス成型して全固体電池評価セル(宝泉株式会社製、型式KP-SolidCell)内に密閉することで、全固体二次電池をそれぞれ作製した。なお、「(1)電池の作製」の作製手順はアルゴン雰囲気にて行った。
(2)評価方法
上記で作製した全固体二次電池を、60℃の恒温槽に入れ、充電終止電圧を2.38V、放電終止電圧を0.38Vとし、充電レート0.05C、放電レート0.05Cの充放電を50サイクル行い、5サイクル目及び50サイクル目の放電容量(mAh/g)を測定した。5サイクル目の放電容量(mAh/g)の結果を表1~3に示す。なお、本開示において、放電容量(mAh/g)における「g」は、正極活物質層における活物質の質量を示す。
また、5サイクル目の放電容量に対する50サイクル目の放電容量の割合を容量維持率(%)とし、サイクル特性について評価した。結果を表1~3に示す。
硫黄含有材料bの粉末X線回折の測定結果を図3に示す。粉末X線回折のピーク強度比(A/B)は930.0/414.0=2.25と求められ、放電容量の低下及びサイクル特性の低下が生じる程度で、硫黄含有材料bに単体硫黄が含まれることが確認できた。
上記結果より、実施例の硫黄含有材料は難燃性が高いことから、電池の安全性を向上させることができることが分かった。また、実施例の硫黄含有材料を用いた電池は、放電容量が大きいことが分かった。また、実施例の硫黄含有材料を用いた電池は、容量維持率が向上したことから、サイクル特性に優れることが分かった。
Claims (8)
- 硫黄変性化合物を含み、
硫黄全含量が50質量%以上であり、
CuKα線を用いた粉末X線回折で得られる、回折角度(2θ)が23.0°~23.4°の範囲内の最大のピーク強度(A)と、回折角度(2θ)が24.8°~25.2°の範囲内の最大のピーク強度(B)との比(A/B)が1.5以下(A/B≦1.5)であることを特徴とする硫黄含有材料。 - 前記硫黄変性化合物が硫黄変性アクリル系化合物であることを特徴とする請求項1に記載の硫黄含有材料。
- 硫黄変性化合物を含み、
硫黄全含量が50質量%以上であり、
CuKα線を用いた粉末X線回折で得られる、回折角度(2θ)が23.0°~23.4°の範囲内の最大のピーク強度(A)と、回折角度(2θ)が24.8°~25.2°の範囲内の最大のピーク強度(B)との比(A/B)が1.5以下(A/B≦1.5)であることを特徴とする硫黄含有電池材料。 - 前記硫黄変性化合物が硫黄変性アクリル系化合物であることを特徴とする請求項3に記載の硫黄含有電池材料。
- 請求項1に記載の硫黄含有材料を含む電極層を有する電極。
- 請求項5に記載の電極を有する電池。
- 前記電極が正極である請求項6に記載の電池。
- 負極がリチウムである請求項7に記載の電池。
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| KR1020257011305A KR20250068669A (ko) | 2022-09-15 | 2023-09-04 | 황 함유 재료, 황 함유 전지 재료, 전극 및 전지 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010044437A1 (ja) | 2008-10-17 | 2010-04-22 | 独立行政法人産業技術総合研究所 | 硫黄変性ポリアクリロニトリル、その製造方法、及びその用途 |
| WO2013001693A1 (ja) * | 2011-06-28 | 2013-01-03 | 株式会社豊田自動織機 | 硫黄系正極活物質とその製造方法及びリチウムイオン二次電池用正極 |
| JP2013054957A (ja) | 2011-09-05 | 2013-03-21 | Toyota Industries Corp | 非水電解質二次電池用正極の製造方法、非水電解質二次電池用正極ならびに非水電解質二次電池 |
| JP2014022123A (ja) | 2012-07-13 | 2014-02-03 | National Institute Of Advanced Industrial & Technology | 二次電池用有機硫黄系正極材料連続製造装置 |
| WO2022004696A1 (ja) * | 2020-06-29 | 2022-01-06 | 株式会社Adeka | 硫黄変性ポリアクリロニトリル、それを含む電極活物質、該電極活物質を含む二次電池用電極、該電極の製造方法及び該電極を用いた非水電解質二次電池 |
| JP2022065974A (ja) | 2020-10-16 | 2022-04-28 | 株式会社Adeka | 非水電解質二次電池用電極の製造方法 |
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- 2023-09-04 CN CN202380065747.2A patent/CN119866350A/zh active Pending
- 2023-09-04 KR KR1020257011305A patent/KR20250068669A/ko active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010044437A1 (ja) | 2008-10-17 | 2010-04-22 | 独立行政法人産業技術総合研究所 | 硫黄変性ポリアクリロニトリル、その製造方法、及びその用途 |
| WO2013001693A1 (ja) * | 2011-06-28 | 2013-01-03 | 株式会社豊田自動織機 | 硫黄系正極活物質とその製造方法及びリチウムイオン二次電池用正極 |
| JP2013054957A (ja) | 2011-09-05 | 2013-03-21 | Toyota Industries Corp | 非水電解質二次電池用正極の製造方法、非水電解質二次電池用正極ならびに非水電解質二次電池 |
| JP2014022123A (ja) | 2012-07-13 | 2014-02-03 | National Institute Of Advanced Industrial & Technology | 二次電池用有機硫黄系正極材料連続製造装置 |
| WO2022004696A1 (ja) * | 2020-06-29 | 2022-01-06 | 株式会社Adeka | 硫黄変性ポリアクリロニトリル、それを含む電極活物質、該電極活物質を含む二次電池用電極、該電極の製造方法及び該電極を用いた非水電解質二次電池 |
| JP2022065974A (ja) | 2020-10-16 | 2022-04-28 | 株式会社Adeka | 非水電解質二次電池用電極の製造方法 |
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| CN119866350A (zh) | 2025-04-22 |
| KR20250068669A (ko) | 2025-05-16 |
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