WO2015125840A1 - ナトリウム二次電池 - Google Patents
ナトリウム二次電池 Download PDFInfo
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- WO2015125840A1 WO2015125840A1 PCT/JP2015/054502 JP2015054502W WO2015125840A1 WO 2015125840 A1 WO2015125840 A1 WO 2015125840A1 JP 2015054502 W JP2015054502 W JP 2015054502W WO 2015125840 A1 WO2015125840 A1 WO 2015125840A1
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- sodium
- positive electrode
- secondary battery
- group
- electrolytic solution
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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
- H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
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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
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0567—Liquid materials characterised by the additives
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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
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0569—Liquid materials characterised by the solvents
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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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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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
- H01M4/48—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
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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
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
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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 invention relates to a sodium secondary battery.
- a sodium secondary battery usually includes at least a pair of electrodes, a positive electrode including a positive electrode active material capable of doping and dedoping sodium ions, and a negative electrode including a negative electrode active material capable of doping and dedoping sodium ions. And an electrolyte.
- Patent Document 1 As an electrolytic solution used for a sodium secondary battery, a sodium secondary battery using an electrolytic solution in which an electrolyte salt made of sodium hexafluorophosphate is dissolved in a solvent made of a saturated cyclic carbonate such as propylene carbonate is examined.
- Patent Document 1 An electrolytic solution used for a sodium secondary battery, a sodium secondary battery using an electrolytic solution in which an electrolyte salt made of sodium hexafluorophosphate is dissolved in a solvent made of a saturated cyclic carbonate such as propylene carbonate is examined.
- an object of the present invention is to provide a sodium secondary battery having excellent output characteristics.
- the electrolytic solution includes the polymer compound in a range of 0.1 wt% to 18 wt% with respect to the electrolytic solution.
- a sodium secondary battery having excellent output characteristics can be provided without changing the composition of the solvent in the electrolytic solution, which is extremely useful industrially.
- the sodium secondary battery of the present invention includes a positive electrode having a positive electrode active material that can be doped and dedoped with sodium ions, a negative electrode having a negative electrode active material that can be doped and dedoped with sodium ions, and an electrolytic solution. Furthermore, it has a separator.
- a laminated body in which a negative electrode, a separator and a positive electrode are stacked, or an electrode group obtained by winding or folding the laminated body is usually stored in a battery can or an aluminum laminate pack, and the electrode group is electrolyzed. It can be produced by impregnating with a liquid.
- a cross section when the electrode group is cut in a direction perpendicular to the winding axis is a circle, an ellipse, a rectangle, a rectangle with rounded corners, or the like.
- the shape can be raised.
- examples of the shape of the battery include a paper shape, a coin shape, a cylindrical shape, and a square shape.
- a pressurizing process such as pressing may be performed after the production in the direction perpendicular to the electrode surface.
- the electrolytic solution used in the sodium secondary battery of the present invention includes a solvent, a sodium salt, and a polymer compound.
- a non-aqueous electrolytic solution using a non-aqueous solvent as a solvent is preferable.
- the electrolytic solution may be in a solution state (sol state) or in a gel state with poor fluidity. Moreover, the sol state and the gel state may be mixed. Examples of the gel include chemically crosslinked gel and / or physically crosslinked gel.
- Sodium salts used in the electrolyte include NaPF 6 , NaBF 4 , NaClO 4 , NaN (SO 2 CF 3 ) 2 , NaN (SO 2 C 2 F 5 ) 2 , NaCF 3 SO 3 , NaAsF 6 , NaSbF 6 , NaBC 4 O 8 , lower aliphatic carboxylic acid sodium salt, NaAlCl 4 NaPO 2 F 2 , Na 2 PO 3 F and the like may be mentioned, and two or more of these may be used in combination.
- a sodium salt containing a fluorine atom containing at least one selected from the group consisting of 3 F, and at least one selected from the group consisting of NaPF 6 , NaBF 4 , NaN (SO 2 CF 3 ) 2
- the sodium salt in the electrolytic solution is preferably contained in a proportion of 0.5 mol or more, and contained in a proportion of 0.7 mol or more with respect to 1 L of the electrolytic solution from the viewpoint of conductivity. More preferably, it is more preferably contained in a proportion of 0.8 mol or more. Further, from the viewpoint of the solubility of the sodium salt in the electrolytic solution, the sodium salt is preferably contained in a proportion of 3.0 mol or less, and contained in a proportion of 2.5 mol or less with respect to 1 L of the electrolytic solution. More preferably, it is more preferably contained in a proportion of 2.0 mol or less, particularly preferably in a proportion of 1.5 mol or less.
- the non-aqueous solvent is preferable as the solvent used in the electrolytic solution, for example, cyclic carbonates such as propylene carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate; dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and the like. 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropyl methyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, etc.
- cyclic carbonates such as propylene carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate; dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and the like.
- 1,2-dimethoxyethane, 1,3-dimethoxypropane pentafluoropropyl methyl
- Ethers esters such as methyl formate and methyl acetate; lactones such as ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -valerolactone, and ⁇ -caprolactone; And nitriles such as butyronitrile; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and 1,3-dimethyl-2-imidazolidinone; carbamates such as 3-methyl-2-oxazolidone; Sulfur-containing compounds such as dimethyl sulfate, dimethyl sulfite, dipropyl sulfite, ethylene sulfite, dimethyl sulfone, ethyl methyl sulfone, diphenyl sulfone, sulfolane, methyl methanesulfonate, dimethyl sulfoxide, and 1,3-propane sultone; Can be used. Two or more of these may be mixed and used
- the non-aqueous solvent used in the electrolytic solution preferably contains at least one selected from the group consisting of ethylene carbonate, propylene carbonate, sulfolane, ⁇ -butyrolactone, and fluoroethylene carbonate, and more preferably ethylene carbonate and / or propylene. Carbonate, and more preferably propylene carbonate.
- Ethylene carbonate, propylene carbonate, sulfolane, gamma butyrolactone and fluoroethylene carbonate are high dielectric constant non-aqueous solvents.
- a high dielectric constant non-aqueous solvent By using a high dielectric constant non-aqueous solvent, the solubility of the polymer compound contained in the electrolyte can be reduced. improves.
- the high dielectric constant non-aqueous solvent is preferably 40% by weight or more, more preferably 50% by weight or more, further preferably 60% by weight or more with respect to the electrolytic solution. Particularly preferred is 70% by weight or more.
- the high dielectric constant non-aqueous solvent is preferably 90% by weight or less.
- the content of the polymer compound in the electrolytic solution is 18% by weight or less, preferably 13% by weight or less, more preferably 9% by weight or less, from the viewpoint of the impregnation property of the electrolytic solution to the electrode. Even more preferably, it is 5% by weight or less. Further, from the viewpoint of enhancing the output characteristics, the content of the polymer compound is 0.1% by weight or more, preferably 0.4% by weight or more, more preferably 1.0% by weight with respect to the electrolytic solution. % Or more, and particularly preferably 2.2% by weight or more.
- the polymer compound preferably contains at least one structural unit selected from the group consisting of the following formulas (A) to (D).
- R 1 and R 3 are each independently an alkylene group having 1 to 20 carbon atoms which may have a substituent
- R 2 and R 4 each independently represent a hydrogen atom, a hydroxyl group
- R 5 is a hydrogen atom or an optionally substituted carbon atom.
- It is an alkyl group of several 1 to 20.
- R 1 and R 3 are each an optionally substituted alkylene group having 1 to 20 carbon atoms, preferably a group represented by —CH 2 — or —C 2 H 4 —, and more preferably. Is a group represented by —CH 2 —.
- R 2 and R 4 are a hydrogen atom (—H), a hydroxyl group (—OH), an alkyl group that may have a substituent, or an alkoxy group that may have a substituent, preferably a hydrogen atom, -CH 3, -C 2 H 5, -C 3 H 7, -C 4 H 9, in -OCH 3, -OC 2 H 5, -OC 3 H 7, -OC 4 H 9 or -OC 5 H 11 And more preferably a group represented by a hydrogen atom, —CH 3 , —C 2 H 5 , —OCH 3 , —OC 2 H 5 , —OC 3 H 7 .
- R 5 is a hydrogen atom (—H) or an alkyl group which may have a substituent, preferably a hydrogen atom, —CH 3 , —C 2 H 5 , —C 3 H 7 or —C 4 H. And a group represented by hydrogen atom or —CH 3 .
- examples of the substituent that the alkylene group having 1 to 20 carbon atoms, the alkyl group having 1 to 20 carbon atoms, and the alkoxy group having 1 to 20 carbon atoms may have include a bromo group (—Br) and a chloro group.
- At least one structural unit selected from the group consisting of the above formulas (A) to (D) is 30 mol% or more, more preferably 50 mol, based on the total of all the structural units. % Or more is preferable.
- Examples of the polymer compound having the structural unit represented by the formula (A) include polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide copolymer, ethylene oxide-alkylene oxide copolymer, ethylene oxide-methyl glycidyl ether copolymer, Polyethylene such as ethylene oxide-2- (2-methoxyethoxy) ethyl glycidyl ether copolymer, ethylene oxide-2-glycidoxy-1, 3-bis (2-methoxyethoxy) propane copolymer, ethylene oxide-propylene oxide copolymer diacrylate
- Examples include ether polymers.
- Examples of the polymer compound having the structural unit represented by the formula (B) include polyacrylic acid esters and polymethacrylic acid esters.
- Polyacrylate esters include methyl polyacrylate, ethyl polyacrylate, polypropyl acrylate, isopropyl polyacrylate, butyl polyacrylate, isobutyl polyacrylate, tertiary butyl polyacrylate, pentyl polyacrylate, poly Examples include methoxyethyl acrylate, ethoxyethyl polyacrylate, 2-ethylhexyl polyacrylate, 2-hydroxyethyl polyacrylate, 2-hydroxypropyl polyacrylate, dimethylaminoethyl polyacrylate, and diethylaminoethyl polyacrylate.
- Polymethacrylates include polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polyisopropyl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, tertiary butyl methacrylate, polypentyl methacrylate, poly Methoxyethyl methacrylate, polyethoxyethyl methacrylate, polypentyl methacrylate, poly 2-ethylhexyl methacrylate, poly 2-hydroxyethyl methacrylate, poly 2-hydroxypropyl methacrylate, polydimethylaminoethyl methacrylate, polydiethylamino methacrylate Ethyl is given.
- Examples of the polymer compound having the structural unit represented by the formula (C) include polyacrylonitrile, acrylonitrile-methyl acrylate copolymer, acrylonitrile-ethyl acrylate copolymer, acrylonitrile-methyl methacrylate copolymer, acrylonitrile.
- Examples of the polymer compound having the structural unit represented by the formula (D) include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, and vinylidene fluoride-hexa. Examples thereof include a fluoropropylene-tetrafluoroethylene copolymer, a vinylidene fluoride-hexafluoropropylene-monomethylmaleic acid ester copolymer, and a vinylidene fluoride-acrylonitrile copolymer.
- the polymer compound preferably has a weight average molecular weight (hereinafter sometimes referred to as Mw) of 1 ⁇ 10 5 or more, and more preferably 2 ⁇ 10 5 or more.
- Mw is preferably 8 ⁇ 10 6 or less, more preferably 4 ⁇ 10 6 or less, further preferably 2 ⁇ 10 6 or less, and even more preferably 9 ⁇ , from the viewpoint of the impregnation property of the electrolyte into the electrode. 10 5 or less.
- the weight average molecular weight can be measured by gel permeation chromatography.
- the polymer compound used in the electrolytic solution preferably has the same structural unit as the polymer compound used as a binder contained in a negative electrode mixture described later. More preferably, it has the same main chain as the polymer compound used as the binder contained in the negative electrode mixture. Here, the main chain is the longest chain forming the polymer compound. However, the molecular weight of the polymer compound used as the binder and the polymer compound contained in the electrolytic solution may be different. By setting it as the said structure, the ion movement between electrolyte solution / negative electrode becomes easy, and resistance is reduced.
- the electrolytic solution used in the present invention can be obtained by adding, stirring, and dissolving a solvent, a sodium salt, and a polymer compound.
- the electrolytic solution may be heated as necessary, and is preferably heated at a temperature near the melting point of the polymer compound.
- a monomer containing a structural unit represented by the above formulas (A) to (D) is mixed with the solvent and sodium salt, and then polymerized.
- the polymerization method include heat polymerization and electrolytic polymerization.
- the electrolytic solution has surface activity such as trioctyl phosphate, diphenyl ether, ethyl octoate, polyoxyethylene ethers having a perfluoroalkyl group, and perfluorooctane sulfonate esters.
- surface activity such as trioctyl phosphate, diphenyl ether, ethyl octoate, polyoxyethylene ethers having a perfluoroalkyl group, and perfluorooctane sulfonate esters.
- One kind or two or more kinds of agents may be added.
- the addition amount of the surfactant is preferably 3% by weight or less, more preferably 0.01 to 1% by weight with respect to the total weight of the electrolytic solution.
- the electrolyte solution preferably has a viscosity of 10 mPa ⁇ s or more and 15000 mPa ⁇ s or less measured under the following condition (1). From the viewpoint of the impregnation property of the electrolytic solution to the electrode, it is more preferably 6000 mPa ⁇ s or less, further preferably 4000 mPa ⁇ s or less, and particularly preferably 2000 mPa ⁇ s or less.
- Condition (1) In the viscometer, a steel cone having a diameter of 40 mm and a cone angle of 4 ° is used, and the viscosity of the electrolytic solution is measured when the steel cone is rotated for 40 seconds at a measurement environment temperature of 23 ° C. and a shear rate of 30 sec ⁇ 1 .
- a stress rheometer AR-550, manufactured by TA Instruments
- the electrolyte solution has a viscosity ratio (measured under the above condition (1) to the viscosity measured under the following condition (2) ( (Hereinafter referred to as TI) is preferably greater than 1.0, more preferably greater than 1.1, and even more preferably greater than 1.5.
- Condition (2) In the viscometer, a steel cone having a diameter of 40 mm and a cone angle of 4 ° is used, and the viscosity of the electrolytic solution is measured when the steel cone is rotated for 40 seconds at a measurement environment temperature of 23 ° C. and a shear rate of 30 sec ⁇ 1 .
- a stress rheometer AR-550, manufactured by TA Instruments
- the positive electrode has a positive electrode active material that can be doped and dedoped with sodium ions.
- a positive electrode may be comprised from a collector and the positive mix containing the said positive electrode active material carry
- the positive electrode mixture contains a conductive material and a binder as necessary in addition to the positive electrode active material.
- the positive electrode active material comprises a sodium-containing transition metal compound, and the sodium-containing transition metal compound can be doped and dedoped with sodium ions.
- sodium-containing transition metal compound examples include the following compounds. That, NaFeO 2, NaMnO 2, NaNiO 2 and NaCoO oxide represented by NaM 3 a1 O 2, such as 2, oxide represented by Na 0.44 Mn 1-a2 M 3 a2 O 2, Na 0.
- a composite metal oxide represented by the following formula (I) can be preferably used as the positive electrode active material.
- a composite metal oxide represented by the following formula (I) as the positive electrode active material, the charge / discharge capacity of the battery can be improved.
- Na a M 1 b M 2 O 2 (I) (Here, M 1 represents one or more elements selected from the group consisting of Mg, Ca, Sr and Ba, and M 2 represents a group consisting of Mn, Fe, Co, Cr, V, Ti and Ni.
- a is a value in the range of 0.5 or more and 1.05 or less
- b is a value in the range of 0 or more and 0.5 or less
- a + b is 0.5 or more and 1 The value is in the range of 10 or less.
- a carbon material can be used as the conductive material.
- the carbon material include graphite powder, carbon black (for example, acetylene black, ketjen black, furnace black, etc.), fibrous carbon material (carbon nanotube, carbon nanofiber, vapor grown carbon fiber, etc.) and the like.
- the carbon material has a large surface area, and when added in a small amount in the electrode mixture, it is possible to improve the conductivity inside the resulting electrode and improve the charge / discharge efficiency and large current discharge characteristics.
- the proportion of the conductive material in the positive electrode mixture is 4 to 20 parts by weight with respect to 100 parts by weight of the positive electrode active material, and two or more kinds may be contained.
- binder used in the positive electrode mixture examples include polymer compounds such as a polymer of a fluorine compound and an addition polymer of a monomer containing an ethylenic double bond not containing a fluorine atom.
- the glass transition temperature of the binder is preferably -50 to 25 ° C. By setting the glass transition temperature within the above range, the flexibility of the obtained positive electrode can be improved, and a sodium secondary battery that can be used sufficiently even in a low temperature environment can be obtained.
- binder used in the positive electrode mixture include polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotri Fluororesins such as fluoroethylene copolymers and tetrafluoroethylene-hexafluoropropylene copolymers; Vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-pentafluoropropylene copolymer, fluoride Fluoro rubbers such as vinylidene-pentafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluor
- Methacrylic polymers such as polymethacrylic acid, polyalkylmethacrylate (the alkyl group has 1 to 20 carbon atoms in the alkyl moiety), methacrylic acid-alkylmethacrylate copolymer;
- Polyether polymers such as polyethylene oxide, polypropylene glycol, polytetramethylene oxide, polyethersulfone, ethylene oxide-propylene oxide copolymer, ethylene oxide-alkylene oxide copolymer; Polyvinyl alcohol (partially or completely saponified), ethylene-vinyl alcohol copolymer, polyvinylpyrrolidone, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-alkyl acrylate (the alkyl group has 1 carbon atom in the alkyl moiety) 20) Olefin such as copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer, ethylene-alkyl me
- the mixing ratio of the binder in the positive electrode mixture is usually 0.5 to 15 parts by weight, preferably 2 to 10 parts by weight with respect to 100 parts by weight of the positive electrode mixture.
- the positive electrode is manufactured, for example, by supporting a positive electrode mixture containing a positive electrode active material that can be doped and dedoped with sodium ions on a positive electrode current collector.
- a positive electrode mixture paste comprising a positive electrode active material, a conductive material, a binder and a solvent is prepared and kneaded.
- coating to a body and drying is mention
- the method for applying the positive electrode mixture paste to the current collector is not particularly limited. Examples thereof include slit die coating method, screen coating method, curtain coating method, knife coating method, gravure coating method, electrostatic spray method and the like.
- drying performed after application coating
- you may perform by heat processing You may carry out by ventilation drying, vacuum drying, etc.
- the temperature is usually about 50 to 150 ° C.
- you may press after drying. Examples of the pressing method include a mold press and a roll press.
- An electrode can be manufactured by the method mentioned above.
- the thickness of the positive electrode mixture is usually about 5 to 500 ⁇ m.
- Examples of the solvent used for the positive electrode mixture paste include organic solvents.
- the organic solvent may be either a polar solvent or a nonpolar solvent.
- Amides such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide and dimethylformamide as polar solvents; Alcohols such as isopropyl alcohol, ethyl alcohol and methyl alcohol; Ethers such as propylene glycol dimethyl ether; Acetone, methyl ethyl ketone, And ketones such as methyl isobutyl ketone.
- nonpolar solvents include hexane and toluene.
- water can also be used as a solvent, and water is preferable in order to suppress the electrode manufacturing cost.
- the ratio of the positive electrode mixture component in the positive electrode mixture paste is usually 40 to 70 wt. %.
- examples of the current collector include Al, Ni, stainless steel and the like, and Al is preferable in that it can be easily processed into a thin film and is inexpensive.
- the shape of the current collector is, for example, a foil shape, a flat plate shape, a mesh shape, a net shape, a lath shape, a punching metal shape, an embossed shape, or a combination thereof (for example, a mesh flat plate). Can be given. Concavities and convexities may be formed by etching on the current collector surface.
- a material in which the polymer compound in the electrolytic solution is supported can be used.
- Examples of a method of supporting the polymer compound on the positive electrode include a method of adding the polymer compound to the positive electrode mixture paste, and applying the obtained paste to a current collector and drying.
- the blending ratio of the polymer compound supported on the positive electrode obtained by this method is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the positive electrode mixture.
- a polymer solution in which the polymer compound is dissolved in a solvent on the positive electrode obtained by applying the positive electrode mixture paste to a current collector and drying it Can be applied and dried.
- the solvent used for the polymer solution include the same solvents as those used for the positive electrode mixture paste.
- the method for applying the polymer solution to the positive electrode is not particularly limited, and examples thereof include a method similar to the method of applying the positive electrode mixture paste to the current collector.
- the blending ratio of the polymer compound supported on the positive electrode obtained by this method is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the positive electrode mixture.
- the sodium-containing transition metal oxide which is an example of the positive electrode active material, can be produced by firing a mixture of metal-containing compounds having a composition that can be used for the sodium-containing transition metal oxide used in the present invention by firing.
- the metal-containing compound containing the corresponding metal element can be produced by weighing and mixing so as to have a predetermined composition, and then firing the resulting mixture.
- a sodium-containing transition metal oxide having a metal element ratio represented by Na: Mn: Fe: Ni 1: 0.3: 0.4: 0.3, which is one of the preferred metal element ratios, is Na 2 CO 3 , MnO 2 , Fe 3 O 4 , and Ni 2 O 3 are weighed so that the molar ratio of Na: Mn: Fe: Ni is 1: 0.3: 0.4: 0.3 And mixing them and firing the resulting mixture.
- M 1 is one or more elements selected from the group consisting of Mg, Ca, Sr and Ba
- a raw material containing M 1 is added during mixing. do it.
- Examples of the metal-containing compound that can be used to produce the sodium-containing transition metal compound used in the present invention include oxides and compounds that can be converted to oxides when decomposed and / or oxidized at high temperatures, such as hydroxides. , Carbonates, nitrates, halides or oxalates can be used.
- Examples of the sodium compound include one or more compounds selected from the group consisting of sodium hydroxide, sodium chloride, sodium nitrate, sodium peroxide, sodium sulfate, sodium bicarbonate, sodium oxalate, and sodium carbonate. Hydrates can also be given. From the viewpoint of handleability, sodium carbonate is more preferable.
- the manganese compound is preferably MnO 2
- the iron compound is preferably Fe 3 O 4
- the nickel compound is preferably Ni 2 O 3 .
- the mixture of metal-containing compounds can be obtained, for example, by obtaining a precursor of a metal-containing compound by the following precipitation method, and mixing the obtained precursor of the metal-containing compound and the sodium compound.
- compounds such as chloride, nitrate, acetate, formate, and oxalate are used as raw materials for M 2 (where M is as defined above), and these are dissolved in water and precipitated.
- the precipitate which the precursor of the metal containing compound contained can be obtained by making it contact.
- chloride is preferred.
- these raw materials are used as acids such as hydrochloric acid, sulfuric acid, nitric acid or the like. It can also be dissolved in an aqueous solution to obtain an aqueous solution containing M.
- LiOH lithium hydroxide
- NaOH sodium hydroxide
- KOH potassium hydroxide
- Li 2 CO 3 lithium carbonate
- Na 2 CO 3 sodium carbonate
- K 2 CO Li 2 CO 3
- hydrates of the compounds can be used. 1 or more types may be used and a compound and a hydrate may be used together.
- the concentration of the compound in the aqueous precipitation agent is about 0.5 to 10 mol / L, preferably about 1 to 8 mol / L.
- KOH is the KOH aqueous solution which melt
- ammonia water can also be mention
- a method of adding a precipitant (including an aqueous precipitant) to the aqueous solution containing M 2 a method of adding an aqueous solution containing 2, in water (including aqueous form precipitant.) aqueous solution and the precipitating agent containing M 2 can be mentioned a method of adding.
- a method of adding an aqueous solution containing M 2 to the aqueous precipitation agent can be preferably used because it is easy to maintain the pH and control the particle size.
- the pH tends to decrease as the aqueous solution containing M 2 is added to the aqueous precipitation agent, but the pH is adjusted to 9 or more, preferably 10 or more. Meanwhile, an aqueous solution containing M 2 is preferably added. This adjustment can also be performed by adding an aqueous precipitation agent.
- a precipitate can be obtained by the above contact.
- This precipitate contains a precursor of a metal-containing compound.
- the slurry is usually formed into a slurry, which is separated into solid and liquid to recover the precipitate.
- Solid-liquid separation may be performed by any method, but from the viewpoint of operability, a method by solid-liquid separation such as filtration is preferably used, and a method of volatilizing the liquid by heating such as spray drying may be used. Moreover, you may perform washing
- the precipitate obtained after the solid-liquid separation may have an excessive component of the precipitant attached thereto, and the component can be reduced by washing.
- the cleaning liquid used for cleaning water is preferably used, and a water-soluble organic solvent such as alcohol or acetone may be used.
- the drying may be performed by heat drying, and may be performed by air drying, vacuum drying, or the like.
- heat drying it is usually carried out at 50 to 300 ° C., preferably about 100 to 200 ° C.
- the mixing method may be either dry mixing or wet mixing, but from the viewpoint of simplicity, dry mixing is preferable.
- Examples of the mixing apparatus include stirring and mixing, a V-type mixer, a W-type mixer, a ribbon mixer, a drum mixer, and a ball mill.
- the firing may be carried out usually at a temperature of about 400 to 1200 ° C., preferably about 500 to 1000 ° C., although it depends on the type of sodium compound used.
- the time for holding at the holding temperature is usually 0.1 to 20 hours, preferably 0.5 to 10 hours.
- the rate of temperature rise to the holding temperature is usually 50 to 400 ° C./hour, and the rate of temperature drop from the holding temperature to room temperature is usually 10 to 400 ° C./hour.
- As the firing atmosphere air, oxygen, nitrogen, argon, or a mixed gas thereof can be used, but air is preferable.
- the halide may play a role as a reaction accelerator (flux).
- the flux include NaF, MnF 3 , FeF 2 , NiF 2 , CoF 2 , NaCl, MnCl 2 , FeCl 2 , FeCl 3 , NiCl 2 , CoCl 2 , NH 4 Cl and NH 4 I.
- These fluxes may be hydrates.
- other metal-containing compounds include Na 2 CO 3 , NaHCO 3 B 2 O 3, and H 3 BO 3 .
- the sodium-containing transition metal compound used in the present invention When used as a positive electrode active material for a sodium secondary battery, the sodium-containing transition metal compound obtained as described above may be optionally used as an industrial product such as a ball mill, a jet mill, or a vibration mill. It may be preferable to adjust the particle size by performing pulverization using an apparatus usually used for the washing, washing, classification and the like. Moreover, you may perform baking twice or more. Further, a surface treatment such as coating the particle surface of the sodium-containing transition metal compound with an inorganic substance containing Si, Al, Ti, Y or the like may be performed. In the case of heat treatment after the surface treatment, the BET specific surface area of the powder after the heat treatment may be smaller than the range of the BET specific surface area before the surface treatment, depending on the temperature of the heat treatment. .
- a negative electrode that can be used in the sodium secondary battery of the present invention an electrode in which a negative electrode mixture containing a negative electrode active material is carried on a negative electrode current collector, a sodium metal or sodium alloy electrode that can be doped and dedoped with sodium ions, Can be used.
- the negative electrode active material in addition to the above-mentioned sodium metal or sodium alloy, natural graphite, artificial graphite, coke, carbon black, pyrolytic carbon, carbon fiber, organic polymer that can be doped and dedoped with sodium ions Examples thereof include carbon materials such as compound fired bodies and metals.
- the shape of the carbon material may be any of a flake shape such as natural graphite, a spherical shape such as mesocarbon microbeads, a fibrous shape such as graphitized carbon fiber, or an aggregate of fine powder.
- the carbon material may play a role as a conductive material.
- the carbon material examples include non-graphitized carbon materials (hereinafter sometimes referred to as hard carbon) such as carbon black, pyrolytic carbons, carbon fibers, and fired organic materials.
- the hard carbon is preferably one having an interlayer distance d (002) by an X-ray diffraction method of 0.360 nm or more and 0.395 nm or less and a crystallite size Lc in the c-axis direction of 1.30 nm or less.
- the R value (ID / IG) obtained by Raman spectroscopy is preferably 1.07 or more and 3 or less.
- the R value (ID / IG) is a Raman spectrum obtained by irradiating a laser having a wavelength of 532 nm and performing Raman spectroscopic measurement (the vertical axis is the intensity of scattered light in arbitrary units, and the horizontal axis is Raman. .
- the hard carbon for example, carbon micro beads made of non-graphitized carbon material can be mentioned, and specifically, ICB (trade name: Nika beads) manufactured by Nippon Carbon Co., Ltd. can be mentioned.
- the shape of the particles constituting the carbon material include a flake shape such as natural graphite, a spherical shape such as mesocarbon microbeads, a fibrous shape such as graphitized carbon fiber, and an aggregate shape of fine particles.
- the average particle diameter is preferably 0.01 ⁇ m or more and 30 ⁇ m or less, more preferably 0.1 ⁇ m or more and 20 ⁇ m or less.
- the metal used for the negative electrode active material include tin, lead, silicon, germanium, phosphorus, bismuth, and antimony.
- the alloy include an alloy composed of two or more metals selected from the group consisting of the above metals, an alloy composed of two or more metals selected from the group consisting of the above metals and transition metals, and Si— Examples of the alloy include Zn, Cu 2 Sb, and La 3 Ni 2 Sn 7 . These metals and alloys are used as an electrode active material by being carried on a current collector in combination with a carbon material.
- Examples of the oxide used for the negative electrode active material include Li 4 Ti 5 O 12 and Na 2 Ti 3 O 7 .
- Examples of sulfides include TiS 2 , NiS 2 , FeS 2 , Fe 3 S 4 and the like.
- Examples of nitrides, Na 3 N, Na 2.6 Co 0.4 Na such as N 3-x M x N (where, M is a transition metal element, 0 ⁇ x ⁇ 3), and the like.
- These carbon materials, metals, oxides, sulfides, and nitrides that are negative electrode active materials may be used in combination, and may be crystalline or amorphous. From the viewpoint of cycle characteristics, it is preferable to use a carbon material as the negative electrode active material, and it is more preferable to use hard carbon.
- These carbon materials, metals, oxides, sulfides, and nitrides are mainly supported on current collectors and used as electrodes.
- the negative electrode mixture may contain a binder and a conductive material.
- Examples of the binder and the conductive material are the same as those used for the positive electrode mixture.
- the same polymer compound as that of the positive electrode can be used.
- the electrolyte solution includes polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide copolymer, ethylene oxide-alkylene oxide copolymer, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer. , Vinylidene fluoride-tetrafluoroethylene copolymer, and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer. These may be used alone or in combination of two or more.
- the polymer compound used as the binder contained in the negative electrode mixture preferably has the same structural unit as the polymer compound used in the electrolytic solution.
- the ratio of the binder in the negative electrode mixture is usually 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight, and more preferably 2 to 12 parts by weight with respect to 100 parts by weight of the negative electrode mixture. .
- Examples of the solvent used for the negative electrode mixture paste include the same solvents as those used for the positive electrode mixture paste.
- Examples of the negative electrode current collector include Al, Cu, Ni, and stainless steel, and Al is preferable because it can be easily processed into a thin film and is inexpensive.
- the shape of the current collector is, for example, a foil shape, a flat plate shape, a mesh shape, a net shape, a lath shape, a punching metal shape, an embossed shape, or a combination thereof (for example, a mesh flat plate). Can be given. Concavities and convexities may be formed by etching on the current collector surface.
- the negative electrode may be one in which the polymer compound in the electrolytic solution is supported.
- Examples of a method of supporting the polymer compound on the negative electrode include a method of adding the polymer compound to the negative electrode mixture paste, and applying the obtained paste to a current collector and drying.
- the blending ratio of the polymer compound supported on the negative electrode obtained by this method is usually 0.1 to 15 parts by weight, preferably 0.5 to 12 parts by weight, with respect to 100 parts by weight of the negative electrode mixture.
- a polymer solution in which the polymer compound is dissolved in a solvent on the negative electrode obtained by applying the negative electrode mixture paste to a current collector and drying it Can be applied and dried.
- the solvent used for the polymer solution include the same solvents as those used for the negative electrode mixture paste.
- the method for applying the polymer solution to the negative electrode is not particularly limited, and examples thereof include the same method as the method of applying the negative electrode mixture paste to the current collector.
- the blending ratio of the polymer compound supported on the negative electrode obtained by this method is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the negative electrode mixture.
- the thickness of the separator is preferably as thin as possible as long as the mechanical strength is maintained in that the volume energy density of the battery is increased and the internal resistance is reduced. In general, the thickness of the separator is preferably about 5 to 200 ⁇ m, more preferably about 5 to 40 ⁇ m.
- the separator preferably has a porous film containing a thermoplastic resin.
- a secondary battery normally, when an abnormal current flows in the battery due to a short circuit between the positive electrode and the negative electrode, the current is interrupted to prevent an excessive current from flowing (shut down). is important. Therefore, the separator shuts down at the lowest possible temperature when the normal use temperature is exceeded (when the separator has a porous film containing a thermoplastic resin, the micropores of the porous film are blocked). Even after the shutdown, even if the temperature in the battery rises to a certain high temperature, it is required to maintain the shutdown state without breaking the film due to the temperature, in other words, to have high heat resistance.
- the thermal breakage of the secondary battery of the present invention It becomes possible to prevent more.
- the heat-resistant porous layer may be laminated on both surfaces of the porous film.
- a separator carrying a polymer compound in the electrolytic solution can be used.
- a method for supporting the polymer compound on the separator include a method in which a polymer solution in which the polymer compound is dissolved in a solvent is applied to the separator and dried.
- the solvent used for the polymer solution include the same solvents as those used for the negative electrode mixture paste.
- Viscosity measurement of electrolyte solution Using a stress rheometer (AR-550, manufactured by TA Instruments) with a steel cone having a diameter of 40 mm and a cone angle of 4 °, a steel cone at a shear rate of 30 sec ⁇ 1 and a measurement environment temperature of 23 ° C. was measured for the viscosity of the electrolyte when rotated for 40 seconds. Subsequently, the viscosity at a shear rate of 100 sec ⁇ 1 was also measured in the same manner.
- AR-550 stress rheometer
- the mixture was placed in an alumina calcination vessel, then calcined by holding for six hours at 850 ° C. in an air atmosphere using an electric furnace and then cooled to room temperature to obtain a composite metal oxide A 1.
- a powder X-ray diffraction analysis of the composite metal oxide A 1 was performed, it was found that the composite metal oxide A 1 was assigned to the ⁇ -NaFeO 2 type crystal structure.
- the composition of the composite metal oxide A1 is analyzed by ICP-AES, the molar ratio of Na: Ca: Fe: Ni: Mn is 0.99: 0.01: 0.4: 0.3: 0.3. Met.
- composite metal oxide A 1 obtained as described above acetylene black as a conductive material, vinylidene fluoride as a binder solution - to produce a positive electrode mixture paste using NMP tetrafluoroethylene copolymer, as a solvent .
- a positive electrode mixture paste was obtained by stirring and mixing for a minute.
- the obtained positive electrode mixture paste was applied to a 20 ⁇ m thick aluminum foil using a doctor blade, dried at 60 ° C. for 2 hours, and then using a roll press (SA-602, manufactured by Tester Sangyo Co., Ltd.)
- a positive electrode AE1 was obtained by rolling at a pressure of 200 kN / m.
- Carbon material C 1 : PVdF-2: NMP 90: 10: 100 (weight ratio) Weighed so as to have a composition, and stirred and mixed using a disperse mat (made by VMA-GETZMANN), an electrode mixture A paste was obtained. The rotation conditions of the rotating blades were 2,000 rpm for 10 minutes. The obtained electrode mixture paste was applied to a copper foil using a doctor blade, dried at 60 ° C. for 2 hours, and then rolled at 100 kN / m using a roll press to obtain a carbon electrode CE1.
- a positive electrode AE 1 punched to a diameter of 14.5 mm is placed in a recess in the lower part of a coin cell (manufactured by Hosen Co., Ltd.), and a carbon electrode CE 1 punched to a diameter of 15.0 mm is used as the negative electrode in the electrolyte.
- a sodium secondary battery BP1 was produced using the electrolytic solution ELP1 as a separator and a polyethylene porous film (thickness 20 ⁇ m). The battery was assembled in a glove box in an argon atmosphere.
- Example 2 (Production of sodium secondary battery BP 2 ) To 1.0M NaPF 6 PC, PEO was added so as to have a weight ratio of 96.3: 3.7, stirred and dissolved in a state heated to 60 ° C., and non-aqueous electrolyte ELP 2 (0.96M NaPF 6 PC / 3.7 wt% PEO). A sodium secondary battery BP 2 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 2 was used as the electrolyte.
- Example 3 Manufacture of sodium secondary battery BP 3
- a 1.3 mol / L NaPF 6 / propylene carbonate solution (1.3 M NaPF 6 PC) (manufactured by Kishida Chemical Co., Ltd.), PC and PEO were added so as to have a weight ratio of 78:12:10, It stirred and dissolved while heating to 60 ° C., to prepare a non-aqueous electrolyte solution ELP 3 (0.99M NaPF 6 PC / 10 wt% PEO).
- a sodium secondary battery BP 3 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 3 was used as the electrolyte.
- Example 4 (Production of sodium secondary battery BP 4 ) To 1.0M NaPF 6 PC, PVdF (manufactured by Kureha Co., Ltd., KF polymer W # 9100, hereinafter referred to as PVdF-1) was added so as to have a weight ratio of 99.5: 0.5, and 150 ° C. The solution was stirred and dissolved in a heated state to prepare a non-aqueous electrolyte ELP 4 (0.99 M NaPF 6 PC / 0.5 wt% PVdF-1). A sodium secondary battery BP4 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 4 was used as the electrolyte.
- Example 5 (Production of sodium secondary battery BP 5 ) To 1.0M NaPF 6 PC, PVdF-1 was added so as to have a weight ratio of 98.0: 2.0, and stirred and dissolved in a state heated to 150 ° C. to obtain a non-aqueous electrolyte ELP 5 (0.99M NaPF 6 PC / 2.0 wt% PVdF-1) was prepared. A sodium secondary battery BP 5 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 5 was used as the electrolyte.
- Example 6> Manufacture of sodium secondary battery BP 6 .
- PVdF-1 was added at a weight ratio of 96.3: 3.7, stirred and dissolved in a state heated to 150 ° C., and non-aqueous electrolyte ELP 6 (0.97M NaPF 6 PC / 3.7 wt% PVdF-1) was prepared.
- a sodium secondary battery BP 6 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 6 was used as the electrolyte.
- Example 7 (Production of sodium secondary battery BP 7 ) To 1.0M NaPF 6 PC, PVdF (manufactured by Kureha Co., Ltd., KF polymer W # 1300) was added to a weight ratio of 96.3: 3.7, and the mixture was stirred and dissolved while heated to 150 ° C. The non-aqueous electrolyte ELP 7 (0.97M NaPF 6 PC / 3.7 wt% PVdF-2) was prepared. A sodium secondary battery BP 7 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 7 was used as the electrolyte.
- Example 8> (Production of sodium secondary battery BP 8 ) A weight of 98.0: 2.0 of 1.0M NaPF 6 PC with vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Arkema, KYNAR FLEX 2750-01, hereinafter referred to as PVdF-HFP-1). was added at a ratio, stirred and dissolved while heating to 0.99 ° C., to prepare a nonaqueous electrolytic solution ELP 8 (0.99M NaPF 6 PC / 2.0 wt% PVdF-HFP-1). A sodium secondary battery BP 8 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 8 was used as the electrolyte.
- Example 9 (Production of sodium secondary battery BP 9 ) To 1.0 M NaPF 6 PC, PVdF-HFP-1 was added so as to have a weight ratio of 96.3: 3.7, stirred and dissolved in a state heated to 150 ° C., and non-aqueous electrolyte ELP 9 ( 0.97M NaPF 6 PC / 3.7 wt% PVdF-HFP-1) was prepared. A sodium secondary battery BP 9 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 7 was used as the electrolyte.
- Example 10> (Production of sodium secondary battery BP 8 ) A weight of 96.3: 3.7 of 1.0M NaPF 6 PC and vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Arkema, KYNAR FLEX 2800-00, hereinafter referred to as PVdF-HFP-2). It was added at a ratio, stirred and dissolved while heating to 0.99 ° C., to prepare a non-aqueous electrolyte solution ELP 10 (0.97M NaPF 6 PC / 3.7 wt% PVdF-HFP-2). A sodium secondary battery BP 10 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte ELP 10 was used as the electrolyte.
- ⁇ Comparative example 2> (Production of sodium secondary battery BH2) 1.3M NaPF 6 PC, PC, and PEO were added at a weight ratio of 80:20, stirred and dissolved in a state heated to 60 ° C., and the non-aqueous electrolyte HLP 1 (1.0M NaPF 6 PC / 20 wt% PEO).
- a sodium secondary battery BH 2 was produced in the same manner as in Example 1 except that the non-aqueous electrolyte HLP 1 was used as the electrolyte.
- ⁇ Charge / discharge test> Before the charge / discharge test, a treatment (stabilization treatment) for stabilizing the operation of the sodium secondary batteries BP 1 to BP 10 , BH 1 , BH 2 was performed, and then an output test and a charge / discharge cycle test were conducted.
- One cycle of energization treatment for discharging CC was performed.
- CC charging was performed at a 0.05 C rate until reaching 3.8 V, and then a current-carrying treatment for performing CC discharging until reaching 2.0 V at a 0.1 C rate was performed for one cycle. Subsequently, after performing CC-CV charging at 0.05C rate until reaching 4.0V (charging is terminated when the current value of 0.005C is reached), CC is discharged until reaching 2.0V at 0.1C rate. 1 cycle was performed. In addition, after conducting CC-CV charging at 0.1C rate until reaching 4.0V (charging completed when reaching 0.02C current value), CC discharge until reaching 2.0V at 0.2C rate For 3 cycles. ⁇ Output test> After the stabilization treatment, an output test was performed under the following conditions.
- the usefulness of the present invention was confirmed. Moreover, the sodium battery of the present invention is relatively excellent in cycle characteristics.
- ⁇ Production Example 3> (Production of carbon material C 1 and the carbon electrode CE 2) Carbon material C 1 of Production Example 2, carboxymethylcellulose (hereinafter referred to as CMC) (Sellogen 4H, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and styrene-butadiene rubber (hereinafter referred to as SBR) as a binder (manufactured by Nippon A & L Co., Ltd.) , AL3001) was used to prepare an electrode mixture paste using pure water as a solvent.
- CMC carboxymethylcellulose
- SBR styrene-butadiene rubber
- VMA-GETZMANN disperse mat
- Example 11 (Production of Sodium Secondary Battery BP 11) As the negative electrode, except for using the carbon electrode CE 2 was punched with a diameter of 15.0 mm, to prepare a sodium secondary battery BP 11 in the same manner as in Example 10.
- the usefulness of the present invention was confirmed. Moreover, the sodium battery of the present invention is relatively excellent in cycle characteristics.
Abstract
Description
本発明のナトリウム二次電池は、ナトリウムイオンをドープかつ脱ドープできる正極活物質を有する正極と、ナトリウムイオンをドープかつ脱ドープできる負極活物質を有する負極と、電解液とを有し、通常、さらにセパレータを有する。
本発明のナトリウム二次電池に用いられる電解液は、溶媒、ナトリウム塩および高分子化合物を含む。電解液としては、溶媒として非水溶媒を用いた非水電解液が好ましい。
電解液に用いられるナトリウム塩としては、NaPF6、NaBF4、NaClO4、NaN(SO2CF3)2、NaN(SO2C2F5)2、NaCF3SO3、NaAsF6、NaSbF6、NaBC4O8、低級脂肪族カルボン酸ナトリウム塩、NaAlCl4NaPO2F2、Na2PO3Fなどがあげられ、これらのうちの2種以上を混合して使用してもよい。これらの中でも、NaPF6、NaBF4、NaSbF6、NaN(SO2CF3)2、NaN(SO2C2F5)2、NaCF3SO3およびNaN(SO2CF3)2、Na2PO3Fからなる群から選ばれる少なくとも1種を含むフッ素原子を含有するナトリウム塩を用いることが好ましく、NaPF6、NaBF4、NaN(SO2CF3)2からなる群から選ばれる少なくとも1種を含むフッ素原子を含有するナトリウム塩を用いることがより好ましい。
本発明において、電解液に用いられる溶媒としては、非水溶媒が好ましく、例えばプロピレンカーボネート、エチレンカーボネート、フルオロエチレンカーボネート、ジフルオロエチレンカーボネートなどの環状炭酸エステル類;ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネートなどの鎖状炭酸エステル類;1,2−ジメトキシエタン、1,3−ジメトキシプロパン、ペンタフルオロプロピルメチルエーテル、2,2,3,3−テトラフルオロプロピルジフルオロメチルエーテル、テトラヒドロフラン、2−メチルテトラヒドロフランなどのエーテル類;ギ酸メチル、酢酸メチルなどのエステル類;γ−ブチロラクトン、γ−バレロラクトン、δ−バレロラクトン、ε−カプロラクトンなどのラクトン類;アセトニトリル、ブチロニトリルなどのニトリル類;N,N−ジメチルホルムアミド、N,N−ジメチルアセトアミド、1,3−ジメチル−2−イミダゾリジノンなどのアミド類;3−メチル−2−オキサゾリドンなどのカーバメート類;ジメチルサルフェート、ジメチルサルファイト、ジプロピルサルファイト、エチレンサルファイト、ジメチルスルホン、エチルメチルスルホン、ジフェニルスルホン、スルホラン、メタンスルホン酸メチル、ジメチルスルホキシド、1,3−プロパンサルトンなどの含硫黄化合物;を用いることができる。非水溶媒として、これらのうちの2種以上を混合して用いてもよい。
上記電解液における高分子化合物の含有量は、電解液の電極への含浸性の観点から、18重量%以下であり、好ましくは13重量%以下であり、より好ましくは9重量%以下であり、さらにより好ましくは5重量%以下である。また、出力特性を高める観点から、該高分子化合物の含有量は、電解液に対して0.1重量%以上であり、好ましくは0.4重量%以上であり、より好ましくは1.0重量%以上であり、特に好ましくは2.2重量%以上である。
(ここで、R1およびR3は、それぞれ独立に、置換基を有してもよい炭素数1~20のアルキレン基であり、R2およびR4は、それぞれ独立に、水素原子、水酸基、置換基を有してもよい炭素数1~20アルキル基または置換基を有してもよい炭素数1~20のアルコキシ基であり、R5は水素原子または置換基を有してもよい炭素数1~20のアルキル基である。)
本発明に用いられる電解液は、溶媒、ナトリウム塩および高分子化合物を添加・攪拌・溶解することで得られる。溶解工程では、必要に応じて該電解液を加熱してもよく、該高分子化合物の融点付近の温度で加熱することが好ましい。
前記電解液は、下記条件(1)で測定した粘度が10mPa・s以上15000mPa・s以下であることが好ましい。電解液の電極への含浸性の観点から、6000mPa・s以下であることがより好ましく、さらに好ましくは4000mPa・s以下であり、特に好ましくは2000mPa・s以下である。また、前記電解液の粘度がある程度高いほうが、正極・セパレータ・負極が固定され、安定作動しやすいことから、10mPa・s以上であることがより好ましく、さらに好ましくは30mPa・s以上であり、さらにより好ましくは50mPa・s以上であり、特に好ましくは100mPa・s以上である。
条件(1)
粘度計において、直径40mm、コーン角度4°のスチールコーンを用い、測定環境温度23℃、せん断速度30sec−1で、該スチールコーンを40秒回転させたときの電解液の粘度を測定する。粘度計としては、ストレスレオメーター(AR−550、TAインスツルメント社製)を用いることができる。
条件(2)
粘度計において、直径40mm、コーン角度4°のスチールコーンを用い、測定環境温度23℃、せん断速度30sec−1で、該スチールコーンを40秒回転させたときの電解液の粘度を測定する。粘度計としては、ストレスレオメーター(AR−550、TAインスツルメント社製)を用いることができる。
本発明において、正極は、ナトリウムイオンをドープかつ脱ドープできる正極活物質を有する。また、正極は、集電体と、集電体の上に担持された、上記正極活物質を含む正極合剤とから構成されてよい。正極合剤は、上記正極活物質以外にも必要に応じて導電材やバインダーを含む
本発明において、正極活物質は、ナトリウム含有遷移金属化合物からなり、該ナトリウム含有遷移金属化合物は、ナトリウムイオンをドープかつ脱ドープすることができる。
すなわち、NaFeO2、NaMnO2、NaNiO2およびNaCoO2等のNaM3 a1O2で表される酸化物、Na0.44Mn1−a2M3 a2O2で表される酸化物、Na0.7Mn1−a2M1 a2O2.05で表される酸化物(M3は1種以上の遷移金属元素、0<a1<1、0≦a2<1);
Na6Fe2Si12O30およびNa2Fe5Si12O30等のNab1M4cSi12O30で表される酸化物(M4は1種以上の遷移金属元素、2≦b1≦6、2≦c≦5);
Na2Fe2Si6O18およびNa2MnFeSi6O18等のNadM5 eSi6O18で表される酸化物(M5は1種以上の遷移金属元素、2≦d≦6、1≦e≦2);
Na2FeSiO6等のNafM6 gSi2O6で表される酸化物(M6は遷移金属元素、MgおよびAlからなる群より選ばれる1種以上の元素、1≦f≦2、1≦g≦2)
NaFePO4、NaMnPO4、Na3Fe2(PO4)3、Na3V2(PO4)2F3、Na1.5VOPO4F0.5、Na4Fe3(PO4)2P2O7、Na4Mn3(PO4)2P2O7、Na4Ni3(PO4)2P2O7、Na4Co3(PO4)2P2O7等のリン酸塩;
Na2FePO4F、Na2VPO4F、Na2MnPO4F、Na2CoPO4F、Na2NiPO4F等のフッ化リン酸塩;
NaFeSO4F、NaMnSO4F、NaCoSO4F、NaFeSO4F等のフッ化硫酸塩;
NaFeBO4、Na3Fe2(BO4)3等のホウ酸塩;
Na3FeF6、Na2MnF6等のNahM7F6で表されるフッ化物(M7は1種以上の遷移金属元素、2≦h≦3);等があげられる。
NaaM1 bM2O2 (I)
(ここで、M1は、Mg、Ca、SrおよびBaからなる群より選ばれる1種以上の元素を表し、M2は、Mn、Fe、Co、Cr、V、TiおよびNiからなる群より選ばれる1種以上の元素を表し、aは0.5以上1.05以下の範囲の値であり、bは0以上0.5以下の範囲の値であり、かつa+bは0.5以上1.10以下の範囲の値である。)
前記導電材としては、炭素材料を用いることができる。炭素材料として、黒鉛粉末、カーボンブラック(例えば、アセチレンブラック、ケッチェンブラック、ファーネスブラック等)、繊維状炭素材料(カーボンナノチューブ、カーボンナノファイバー、気相成長炭素繊維等)などをあげることができる。上記炭素材料は、表面積が大きく、電極合剤中に少量添加されることにより、得られる電極内部の導電性を高め、充放電効率および大電流放電特性を向上させることも可能である。通常、正極合剤中の導電材の割合は、正極活物質100重量部に対して4~20重量部であり、2種以上含有してもよい。
前記正極合剤に用いられるバインダーとしては、例えば、フッ素化合物の重合体やフッ素原子を含まないエチレン性二重結合を含む単量体の付加重合体などの高分子化合物があげられる。
フッ化ビニリデン−ヘキサフルオロプロピレン共重合体、フッ化ビニリデン−テトラフルオロエチレン共重合体、フッ化ビニリデン−ヘキサフルオロプロピレン−テトラフルオロエチレン共重合体、フッ化ビニリデン−ペンタフルオロプロピレン共重合体、フッ化ビニリデン−ペンタフルオロプロピレン−テトラフルオロエチレン共重合体、フッ化ビニリデン−パーフルオロメチルビニルエーテル−テトラフルオロエチレン共重合体、フッ化ビニリデン−クロロトリフルオロエチレン共重合体等のフッ素ゴム;
ポリアクリル酸、ポリアクリル酸アルカリ塩(ポリアクリル酸ナトリウム、ポリアクリル酸カリウム、ポリアクリル酸リチウム等)、ポリアクリル酸アルキル(アルキル部分の炭素数は1から20)、アクリル酸−アクリル酸アルキル(アルキル部分の炭素数は1から20)共重合体、ポリアクリロニトリル、アクリル酸−アクリル酸アルキル−アクリロニトリル共重合体、ポリアクリルアミド、アクリロニトリル−ブタジエン共重合体、アクリロニトリル−ブタジエン共重合体水素化物等のアクリル系ポリマー;
ポリメタクリル酸、ポリメタクリル酸アルキル(アルキル基はアルキル部分の炭素数は1から20)、メタクリル酸−メタクリル酸アルキル共重合体等のメタクリル系ポリマー;
ポリエチレンオキシド、ポリプロピレングリコール、ポリテトラメチレンオキシド、ポリエーテルスルホン、エチレンオキシド−プロピレンオキシド共重合体、エチレンオキシド−アルキレンオキシド共重合体等のポリエーテル系ポリマー;
ポリビニルアルコール(部分ケン化または完全ケン化)、エチレン−ビニルアルコール共重合体、ポリビニルピロリドン、エチレン−酢酸ビニル共重合体、エチレン−酢酸ビニル−アクリル酸アルキル(アルキル基はアルキル部分の炭素数は1から20)共重合体、エチレン−メタクリル酸共重合体、エチレン−アクリル酸共重合体、エチレン−メタクリル酸アルキル共重合体、エチレン−アクリル酸アルキル共重合体、エチレン−アクリロニトリル共重合体等のオレフィン系ポリマー;
アクリロニトリル−スチレン−ブタジエン共重合体、スチレン、アクリロニトリル共重合体、スチレン−ブタジエン共重合体、スチレン−ブタジエン共重合体水素化物等のスチレン含有ポリマーがあげられる。
特に、ハロゲン化ビニリデン由来の構造単位を有する共重合体を用いた場合、正極合剤密度の高い電極が得られやすく、電池の体積エネルギー密度が向上するため好ましい。
正極は、例えば、ナトリウムイオンをドープかつ脱ドープできる正極活物質を含む正極合剤を、正極集電体に担持することで製造される。正極集電体に正極合剤を担持する方法としては、例えば、正極活物質、導電材、バインダーおよび溶媒からなる正極合剤ペーストを作製、混練し、得られた正極合剤ペーストを、集電体へ塗布、乾燥する方法があげられる。正極合剤ペーストを、集電体へ塗布する方法としては特に制限されない。例えば、スリットダイ塗工法、スクリーン塗工法、カーテン塗工法、ナイフ塗工法、グラビア塗工法、静電スプレー法等の方法があげられる。また、塗布後に行う乾燥としては、熱処理によって行ってもよいし、送風乾燥、真空乾燥などにより行ってもよい。熱処理により乾燥を行う場合には、その温度は、通常50~150℃程度である。また、乾燥後にプレスを行ってもよい。プレス方法は、金型プレスやロールプレスなどの方法をあげることができる。以上にあげた方法により、電極を製造することができる。また、正極合剤の厚みは、通常5~500μm程度である。
正極活物質の一例であるナトリウム含有遷移金属酸化物は、焼成により本発明に用いられるナトリウム含有遷移金属酸化物となり得る組成を有する金属含有化合物の混合物を焼成することによって製造できる。具体的には、対応する金属元素を含有する金属含有化合物を所定の組成となるように秤量し混合した後に、得られた混合物を焼成することによって製造できる。例えば、好ましい金属元素比の一つであるNa:Mn:Fe:Ni=1:0.3:0.4:0.3で表される金属元素比を有するナトリウム含有遷移金属酸化物は、Na2CO3、MnO2、Fe3O4、Ni2O3の各原料を、Na:Mn:Fe:Niのモル比が1:0.3:0.4:0.3となるように秤量し、それらを混合し、得られた混合物を焼成することによって製造できる。ナトリウム含有遷移金属酸化物がM1(M1は、Mg、Ca、SrおよびBaからなる群より選ばれる1種以上の元素)を含有するときは、混合時に、M1を含有する原料を追加すればよい。
具体的には、M2(ここで、Mは前記と同義)の原料として、塩化物、硝酸塩、酢酸塩、蟻酸塩、蓚酸塩等の化合物を用いて、これらを水に溶解し、沈殿剤と接触させることで金属含有化合物の前駆体が含有した沈殿物を得ることができる。これらの原料の中でも、塩化物が好ましい。また、水に溶解し難い原料を用いる場合、すなわち、例えば、原料として、酸化物、水酸化物、金属材料を用いる場合には、これらの原料を、塩酸、硫酸、硝酸等の酸またはこれらの水溶液に溶解させて、Mを含有する水溶液を得ることもできる。
本発明のナトリウム二次電池で用いることができる負極としては、負極活物質を含む負極合剤を負極集電体に担持した電極、ナトリウムイオンをドープかつ脱ドープ可能なナトリウム金属またはナトリウム合金電極を用いることができる。負極活物質としては、前記のナトリウム金属またはナトリウム合金以外に、ナトリウムイオンをドープかつ脱ドープすることができる天然黒鉛、人造黒鉛、コークス類、カーボンブラック、熱分解炭素類、炭素繊維、有機高分子化合物焼成体などの炭素材料、金属、があげられる。炭素材料の形状としては、例えば天然黒鉛のような薄片状、メソカーボンマイクロビーズのような球状、黒鉛化炭素繊維のような繊維状、または微粉末の凝集体などのいずれでもよい。ここで、炭素材料は、導電材としての役割を果たす場合もある。
本発明のナトリウム二次電池で用いることができるセパレータとしては例えば、ポリエチレン、ポリプロピレンなどのポリオレフィン樹脂、フッ素樹脂、含窒素芳香族重合体などの材質からなる、多孔質フィルム、不織布、織布などの形態を有する材料を用いることができる。また、これらの材質を2種以上用いた単層または積層セパレータとしてもよい。セパレータとしては、例えば特開2000−30686号公報、特開平10−324758号公報等に記載のセパレータをあげることができる。セパレータの厚みは、電池の体積エネルギー密度が上がり、内部抵抗が小さくなるという点で、機械的強度が保たれる限り薄いほど好ましい。セパレータの厚みは一般に、5~200μm程度が好ましく、より好ましくは5~40μm程度である。
ナトリウム含有遷移金属化合物の粉末X線回折測定は株式会社リガク製RINT2500TTR型を用いて行った。測定は、ナトリウム含有遷移金属化合物を専用のホルダーに充填し、CuKα線源を用いて、回折角2θ=10~90°の範囲にて行い、粉末X線回折図形を得た。ハードカーボンについても上記と同様の操作にて粉末X線回折図形を得た。
粉末を塩酸に溶解させた後、誘導結合プラズマ発光分析法(SII製、SPS3000、以下ICP−AESと呼ぶことがある。)を用いて測定した。
直径40mm、コーン角度4°のスチールコーンを取り付けたストレスレオメーター(AR−550、TAインスツルメント社製)を用い、せん断速度30sec−1、測定環境温度23℃でスチールコーンを40秒回転させた時の電解液の粘度を測定した。続けて同様の操作にて、せん断速度100sec−1の粘度も測定した。
ポリプロピレン製ビーカー内で、蒸留水300mlに、水酸化カリウム44.88gを添加、攪拌により溶解し、水酸化カリウムを完全に溶解させ、水酸化カリウム水溶液(沈殿剤)を調製した。また、別のポリプロピレン製ビーカー内で、蒸留水300mlに、塩化鉄(II)四水和物21.21g、塩化ニッケル(II)六水和物19.02g、塩化マンガン(II)四水和物15.83gを添加、攪拌により溶解し、鉄−ニッケル−マンガン含有水溶液を得た。前記沈殿剤を攪拌しながら、これに前記鉄−ニッケル−マンガン含有水溶液を滴下することで、沈殿物が生成したスラリーを得た。次いで、該スラリーについて、ろ過・蒸留水洗浄を行い、100℃で乾燥させて沈殿物を得た。沈殿物と炭酸ナトリウムと水酸化カルシウムとをモル比でFe:Na:Ca=0.4:0.99:0.01となるようにして秤量した後、メノウ乳鉢を用いて乾式混合して混合物を得た。次いで、該混合物をアルミナ製焼成容器に入れ、電気炉を用いて大気雰囲気中850℃で6時間保持して焼成を行い、室温まで冷却し、複合金属酸化物A1を得た。複合金属酸化物A1の粉末X線回折分析を行うと、α−NaFeO2型の結晶構造に帰属されることがわかった。また、ICP−AESにより、複合金属酸化物A1の組成を分析すると、Na:Ca:Fe:Ni:Mnのモル比は0.99:0.01:0.4:0.3:0.3であった。
そして、上記のようにして得られた複合金属酸化物A1を導電材としてアセチレンブラック、バインダー溶液としてフッ化ビニリデン−テトラフルオロエチレン共重合体、溶媒としてNMPを用いた正極合剤ペーストを作製した。複合金属酸化物A1:導電材:バインダー:NMP=90:5:5:100(重量比)の組成となるように秤量し、ディスパーマット(VMA−GETZMANN社製)を用い4,000rpm、5分間攪拌、混合することで、正極合剤ペーストを得た。得られた正極合剤ペーストを、厚さ20μmのアルミ箔にドクターブレードを用いて塗工し、60℃で2時間乾燥後、ロールプレス(SA−602、テスター産業株式会社製)を用いて、200kN/mの圧力で圧延することで正極AE1を得た。
日本カーボン社製のICB(商品名:ニカビーズ)を焼成炉に導入し、炉内をアルゴンガス雰囲気下とした後、アルゴンガスを毎分0.1L/g(炭素材料の重量)の割合で流通させながら、室温から毎分5℃の速度で1600℃まで昇温し、1600℃で1時間保持した後、冷却し、炭素材料C1を得た。炭素材料C1の粉末X線回折測定より、層間距離d(002)は0.368nmであり、c軸方向の結晶子の大きさLcは1.17nmであることが分かった。また、ラマン分光測定より得られるR値(ID/IG)は1.41であることが分かった。炭素材料C1、バインダーとしてポリフッ化ビニリデン(株式会社クレハ製、KFポリマー W#1300。以下、PVdF−2と呼ぶ。)、溶媒としてNMP(キシダ化学株式会社製)を用いた電極合剤ペーストを作製した。炭素材料C1:PVdF−2:NMP=90:10:100(重量比)の組成となるように秤量し、ディスパーマット(VMA−GETZMANN社製)を用い攪拌、混合することで、電極合剤ペーストを得た。回転羽の回転条件は、2,000rpm、10分間とした。得られた電極合剤ペーストを、銅箔にドクターブレードを用いて塗工し、60℃で2時間乾燥後、ロールプレスを用いて、100kN/mで圧延することで炭素電極CE1を得た。
1.0mol/LのNaPF6/プロピレンカーボネート溶液(1.0M NaPF6 PC)(キシダ化学株式会社製)に、Mw=100,000のポリエチレンオキシド(PEO)(Johnson Matthey社製)を98.0:2.0の重量比となるように添加し、60℃に加熱した状態で攪拌・溶解し、非水電解液ELP1(0.98M NaPF6 PC/2.0重量%PEO)を調整した。コインセル(宝泉株式会社製)の下側パーツの窪みに、直径14.5mmに打ち抜いた正極AE1を置き、負極として、直径15.0mmに打ち抜いた炭素電極CE1を、電解液に非水電解液ELP1を、セパレータとしてポリエチレン多孔質フィルム(厚み20μm)を用いてナトリウム二次電池BP1を作製した。なお、電池の組み立てはアルゴン雰囲気のグローブボックス内で行った。
1.0M NaPF6 PCに、PEOを96.3:3.7の重量比となるように添加し、60℃に加熱した状態で攪拌・溶解し、非水電解液ELP2(0.96M NaPF6 PC/3.7重量%PEO)を調整した。電解液に非水電解液ELP2を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP2を作製した。
1.3mol/LのNaPF6/プロピレンカーボネート溶液(1.3M NaPF6 PC)(キシダ化学株式会社製)と、PCと、PEOとを78:12:10の重量比となるように添加し、60℃に加熱した状態で攪拌・溶解し、非水電解液ELP3(0.99M NaPF6 PC/10重量%PEO)を調整した。電解液に非水電解液ELP3を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP3を作製した。
1.0M NaPF6 PCに、PVdF(株式会社クレハ製、KFポリマーW#9100。以下、PVdF−1と呼ぶ。)を99.5:0.5の重量比となるように添加し、150℃に加熱した状態で攪拌・溶解し、非水電解液ELP4(0.99M NaPF6 PC/0.5重量%PVdF−1)を調整した。電解液に非水電解液ELP4を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP4を作製した。
1.0M NaPF6 PCに、PVdF−1を98.0:2.0の重量比となるように添加し、150℃に加熱した状態で攪拌・溶解し非水電解液ELP5(0.99M NaPF6 PC/2.0重量%PVdF−1)を調整した。電解液に非水電解液ELP5を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP5を作製した。
1.0M NaPF6 PCに、PVdF−1を96.3:3.7の重量比となるように添加し、150℃に加熱した状態で攪拌・溶解し非水電解液ELP6(0.97M NaPF6 PC/3.7重量%PVdF−1)を調整した。電解液に非水電解液ELP6を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP6を作製した。
1.0M NaPF6 PCに、PVdF(株式会社クレハ製、KFポリマーW#1300)を96.3:3.7の重量比となるように添加し、150℃に加熱した状態で攪拌・溶解し、非水電解液ELP7(0.97M NaPF6 PC/3.7重量%PVdF−2)を調整した。電解液に非水電解液ELP7を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP7を作製した。
1.0M NaPF6 PCに、フッ化ビニリデン−ヘキサフルオロプロピレン共重合体(アルケマ社製、KYNAR FLEX 2750−01。以下、PVdF−HFP−1と呼ぶ。)を98.0:2.0の重量比となるように添加し、150℃に加熱した状態で攪拌・溶解し、非水電解液ELP8(0.99M NaPF6 PC/2.0重量%PVdF−HFP−1)を調整した。電解液に非水電解液ELP8を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP8を作製した。
1.0M NaPF6 PCに、PVdF−HFP−1を96.3:3.7の重量比となるように添加し、150℃に加熱した状態で攪拌・溶解し、非水電解液ELP9(0.97M NaPF6 PC/3.7重量%PVdF−HFP−1)を調整した。電解液に非水電解液ELP7を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP9を作製した。
1.0M NaPF6 PCに、フッ化ビニリデン−ヘキサフルオロプロピレン共重合体(アルケマ社製、KYNAR FLEX 2800−00。以下、PVdF−HFP−2と呼ぶ。)を96.3:3.7の重量比となるように添加し、150℃に加熱した状態で攪拌・溶解し、非水電解液ELP10(0.97M NaPF6 PC/3.7重量%PVdF−HFP−2)を調整した。電解液に非水電解液ELP10を用いた以外は、実施例1と同様の操作でナトリウム二次電池BP10を作製した。
1.0M NaPF6 PCを非水電解液として用いた以外は、実施例1と同様の操作でナトリウム二次電池BH1を作製した。
1.3M NaPF6 PCと、PCと、PEOとを80:20の重量比となるように添加し、60℃に加熱した状態で攪拌・溶解し、非水電解液HLP1(1.0M NaPF6 PC/20重量%PEO)を調整した。電解液に非水電解液HLP1を用いた以外は、実施例1と同様の操作でナトリウム二次電池BH2を作製した。
充放電試験の前に、ナトリウム二次電池BP1~BP10、BH1、BH2の作動を安定化させる処置(安定化処置)を行った後、出力試験および充放電サイクル試験を行った。
<安定化処置>
レストポテンシャルから3.2Vに達するまで、0.05Cレート(20時間で完全充電する速度)でCC充電を行った後、0.1Cレート(10時間で完全充電する速度)で2.0Vに達するまでCC(コンスタントカレント)放電する通電処置を1サイクル行った。さらに、3.8Vに達するまで0.05CレートでCC充電を行った後、0.1Cレートで2.0Vに達するまでCC放電する通電処置を1サイクル行った。続いて、4.0Vに達するまで0.05CレートでCC−CV充電(0.005C電流値到達で充電終了)を行った後、0.1Cレートで2.0Vに達するまでCC放電する通電処置を1サイクル行った。加えて、4.0Vに達するまで0.1CレートでCC−CV充電(0.02C電流値到達で充電終了)を行った後、0.2Cレートで2.0Vに達するまでCC放電する通電処置を3サイクル行った。
<出力試験>
上記安定化処置の後、以下の条件で出力試験を行った。4.0Vに達するまで0.2CレートでCC−CV充電(0.02C電流値到達で充電終了)を行った後、0.2Cレートで2.0Vに達するまでCC放電する充放電試験を行った。その後、充電条件は上記条件と同様とし、放電電流を0.5、1、2、5、10Cレートとした出力試験を行った。表1には、0.2C放電容量に対する5C放電容量の比(5C放電容量/0.2C放電容量×100(%))を出力特性として示す。
<充放電サイクル試験>
上記出力試験後、以下の条件で充放電サイクル試験を行った。4.0Vに達するまで0.2CレートでCC−CV充電(0.02C電流値到達で充電終了)を行った後、0.2Cレートで2.0Vに達するまでCC放電する充放電試験を行った。その後、4.0Vに達するまで1CレートでCC充電を行った後、0.5Cレートで2.0Vに達するまでCC放電する充放電試験を49サイクル行った。最後に、4.0Vに達するまで0.2CレートでCC−CV充電(0.02C電流値到達で充電終了)を行った後、0.2Cレートで2.0Vに達するまでCC放電する充放電試験を行った。表1には、充放電サイクル試験前後での放電容量維持率(サイクル試験後0.2C放電容量/サイクル試験前0.2C放電容量×100(%))をサイクル特性として示す。
製造例2の炭素材料C1、バインダーとしてカルボキシメチルセルロース(以下、CMCと呼ぶ)(第一工業製薬株式会社製、セロゲン4H)とスチレン−ブタジエンゴム(以下、SBRと呼ぶ)(日本エイアンドエル株式会社製、AL3001)を、溶媒として純水を用いた電極合剤ペーストを作製した。炭素材料C1:CMC:SBR=97:2:1(重量比)の組成となるように秤量し、ディスパーマット(VMA−GETZMANN社製)を用い攪拌、混合することで、電極合剤ペーストを得た。回転羽の回転条件は、2,000rpm、10分間とした。得られた電極合剤ペーストを、銅箔にドクターブレードを用いて塗工し、60℃で2時間乾燥後、ロールプレスを用いて、100kN/mで圧延することで炭素電極CE2を得た。
負極として、直径15.0mmに打ち抜いた炭素電極CE2を用いた以外は、実施例10と同様の操作でナトリウム二次電池BP11を作製した。
負極として、直径15.0mmに打ち抜いた炭素電極CE2を用いた以外は、比較例1と同様の操作でナトリウム二次電池BH3を作製した。
ナトリウム二次電池BP11、BH3の作動を安定化させる処置(安定化処置)を行った後、出力試験および充放電サイクル試験を行った。安定化処置条件、出力試験条件、充放電サイクル試験条件は上述と同様である。表2には、0.2C放電容量に対する5C放電容量の比(5C放電容量/0.2C放電容量×100(%))を出力特性として示し、充放電サイクル試験前後での放電容量維持率(サイクル試験後0.2C放電容量/サイクル試験前0.2C放電容量×100(%))をサイクル特性として示す。
Claims (6)
- ナトリウムイオンをドープかつ脱ドープできる正極活物質を有する正極と、ナトリウムイオンをドープかつ脱ドープできる負極活物質を有する負極と、溶媒、ナトリウム塩および高分子化合物を含む電解液とを有するナトリウム二次電池であって、該電解液は、該高分子化合物を、電解液に対して0.1重量%以上18重量%以下の範囲で含むナトリウム二次電池。
- 前記電解液が、エチレンカーボネート、プロピレンカーボネ−ト、スルホラン、γ−ブチロラクトンおよびフルオロエチレンカーボネートからなる群より選ばれる少なくとも1種の非水溶媒を、前記電解液に対して40重量%以上90重量%以下の範囲で含む請求項1に記載のナトリウム二次電池。
- 下記条件(1)で測定した前記電解液の粘度が10mPa・s以上15000mPa・s以下の範囲である請求項1のいずれかに記載のナトリウム二次電池。
条件(1)
粘度計において、直径40mm、コーン角度4°のスチールコーンを用い、測定環境温度23℃、せん断速度30sec−1で、該スチールコーンを40秒回転させたときの電解液の粘度を測定する。 - 前記負極が負極活物質とバインダーとを有し、該負極活物質がハードカーボンである請求項1のいずれかに記載のナトリウム二次電池。
- 前記正極が正極活物質、導電材およびバインダーを有し、該正極活物質が下記式(I)で示される請求項1から5のいずれかに記載のナトリウム二次電池。
NaaM1 bM2O2 (I)
(ここで、M1は、Mg、Ca、SrおよびBaからなる群より選ばれる1種以上の元素を表し、M2は、Mn、Fe、Co、Cr、V、TiおよびNiからなる群より選ばれる1種以上の元素を表し、aは0.5以上1.05以下の範囲の値であり、bは0以上0.5以下の範囲の値であり、かつa+bは0.5以上1.10以下の範囲の値である。)
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US15/119,926 US20170062868A1 (en) | 2014-02-21 | 2015-02-09 | Sodium secondary battery |
CN201580009065.5A CN106030888A (zh) | 2014-02-21 | 2015-02-09 | 钠二次电池 |
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WO2017067994A1 (fr) * | 2015-10-21 | 2017-04-27 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | Procede de fabrication d'un accumulateur du type sodium-ion |
Families Citing this family (10)
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HUE050759T2 (hu) * | 2013-04-05 | 2021-01-28 | Solvay | Nátrium-ion akkumulátor |
CN106602066A (zh) * | 2016-12-30 | 2017-04-26 | 东莞市佳乾新材料科技有限公司 | 一种钠离子电池负极材料及其制备方法和钠离子电池 |
CN111313093B (zh) * | 2019-12-24 | 2021-01-29 | 安徽圣格能源科技有限公司 | 电解液和锂电池 |
CN113381075A (zh) * | 2021-06-09 | 2021-09-10 | 中南大学 | 一种适配于硬碳负极的钠离子电池电解液及其制备和使用方法 |
CN113437356B (zh) * | 2021-06-26 | 2022-03-22 | 宁德时代新能源科技股份有限公司 | 平板式钠金属电池、电化学装置 |
CN114122516A (zh) * | 2021-11-05 | 2022-03-01 | 复旦大学 | 一种不可燃的高安全性钠离子电池 |
CN114050246B (zh) * | 2021-11-16 | 2023-02-07 | 郑州大学 | 微米级多孔硫酸亚铁钠/碳复合正极材料及其制备的钠离子电池或钠电池 |
CN114864932A (zh) * | 2022-06-21 | 2022-08-05 | 深圳名飞远科技有限公司 | 一种钠离子电池正极材料的制备方法 |
CN116632233B (zh) * | 2023-07-19 | 2023-09-29 | 成都锂能科技有限公司 | 一种高性能掺杂钠离子电池硬碳负极材料及其制备方法 |
CN116779847B (zh) * | 2023-08-11 | 2024-01-23 | 深圳海辰储能控制技术有限公司 | 正极极片及其制备方法、储能装置和用电装置 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005071976A (ja) * | 2003-04-01 | 2005-03-17 | Sony Corp | 電池 |
JP2010044958A (ja) * | 2008-08-13 | 2010-02-25 | Sony Corp | 二次電池およびその製造方法、ならびに負極、正極および電解質 |
JP2010527133A (ja) * | 2007-05-15 | 2010-08-05 | エルジー・ケム・リミテッド | 二次電池およびその製造方法 |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7718736B2 (en) * | 2005-06-30 | 2010-05-18 | Freudenberg-Nok General Partnership | Base resistant FKM-TPV elastomers |
JP4363436B2 (ja) * | 2006-10-13 | 2009-11-11 | ソニー株式会社 | 二次電池 |
KR101041722B1 (ko) * | 2009-01-09 | 2011-06-14 | 주식회사 엘지화학 | 공융혼합물과 니트릴 화합물을 포함하는 전해질 및 이를 구비한 전기화학소자 |
KR101943647B1 (ko) * | 2009-02-23 | 2019-01-29 | 가부시키가이샤 무라타 세이사쿠쇼 | 비수 전해질 조성물, 비수 전해질 이차 전지 및 비수 전해질 이차 전지의 제조 방법 |
JP5625390B2 (ja) * | 2009-03-13 | 2014-11-19 | 住友化学株式会社 | 複合金属酸化物、電極およびナトリウム二次電池 |
JP2011171096A (ja) * | 2010-02-18 | 2011-09-01 | Sony Corp | 非水電解質電池 |
JP6086467B2 (ja) * | 2011-03-28 | 2017-03-01 | 日産自動車株式会社 | ナトリウムイオン二次電池 |
US20130052509A1 (en) * | 2011-08-25 | 2013-02-28 | GM Global Technology Operations LLC | Lithium ion battery with electrolyte-embedded separator particles |
-
2015
- 2015-02-09 JP JP2016504142A patent/JPWO2015125840A1/ja active Pending
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Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005071976A (ja) * | 2003-04-01 | 2005-03-17 | Sony Corp | 電池 |
JP2010527133A (ja) * | 2007-05-15 | 2010-08-05 | エルジー・ケム・リミテッド | 二次電池およびその製造方法 |
JP2010044958A (ja) * | 2008-08-13 | 2010-02-25 | Sony Corp | 二次電池およびその製造方法、ならびに負極、正極および電解質 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017067994A1 (fr) * | 2015-10-21 | 2017-04-27 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | Procede de fabrication d'un accumulateur du type sodium-ion |
FR3042915A1 (fr) * | 2015-10-21 | 2017-04-28 | Commissariat Energie Atomique | Procede de fabrication d'un accumulateur du type sodium-ion |
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