WO2017199606A1 - NEGATIVE ELECTRODE MATERIAL FOR Li ION SECONDARY BATTERIES, NEGATIVE ELECTRODE FOR Li ION SECONDARY BATTERIES, AND Li ION SECONDARY BATTERY - Google Patents
NEGATIVE ELECTRODE MATERIAL FOR Li ION SECONDARY BATTERIES, NEGATIVE ELECTRODE FOR Li ION SECONDARY BATTERIES, AND Li ION SECONDARY BATTERY Download PDFInfo
- Publication number
- WO2017199606A1 WO2017199606A1 PCT/JP2017/013962 JP2017013962W WO2017199606A1 WO 2017199606 A1 WO2017199606 A1 WO 2017199606A1 JP 2017013962 W JP2017013962 W JP 2017013962W WO 2017199606 A1 WO2017199606 A1 WO 2017199606A1
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- WO
- WIPO (PCT)
- Prior art keywords
- negative electrode
- ion secondary
- particles
- secondary battery
- containing oxide
- Prior art date
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
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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
-
- 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
-
- 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
- a Li ion conductive metal oxide is coated on the surface of a Si particle that can be alloyed with Li, and a Li ion conductive metal oxide is coated on the surface of the Li ion conductive metal oxide film.
- the present invention relates to a negative electrode material for a secondary battery.
- Li-ion secondary batteries are widely used as power sources for electronic devices because of their excellent characteristics of high voltage and high energy density.
- the current Li ion secondary batteries are mainly those using LiCoO 2 for the positive electrode and graphite for the negative electrode.
- the graphite of the negative electrode is excellent in reversibility of charge and discharge, but the discharge capacity has already reached a value close to the theoretical value of 372 mAh / g corresponding to the intercalation compound LiC 6 . For this reason, in order to achieve higher energy density, it is necessary to develop a negative electrode material having a discharge capacity larger than that of graphite.
- Si and SiO have attracted attention as active materials for forming an alloy with Li having a discharge capacity far exceeding that of graphite as a negative electrode material replacing graphite. Since the Si-based negative electrode has a large volume expansion associated with alloying at the time of charging, it easily deteriorates, and as a measure for reducing the expansion, atomization of particles is effective. However, the active material surface becomes active due to atomization, and the reductive decomposition of the electrolytic solution is promoted at the time of charging. Therefore, the practical cycle characteristics are not obtained.
- Patent Document 1 proposes a carbon material characterized in that it is a metal-containing hollow carbon particle containing Si in an internal void, and Si is coated with Cu or Ni nanoparticles.
- the surface of Si is only coated with a metal element that imparts conductivity. This metal element not only lowers Li ion conduction, but is also insufficient to suppress reductive decomposition of the electrolyte during charging. As a result, accumulation of decomposition product residues causes the electrode to expand and cause cycle deterioration.
- the hollow carbon particles have a high bulk density and cannot increase the density of the negative electrode.
- Patent Document 2 proposes a negative electrode material in which a composite of a nano-sized Si particle surrounded by an Li-containing oxide and a carbon material is coated with carbon.
- the amount of oxide surrounding Si is excessive, about 35 to 88% by mass, so that the resistance of Li ion conduction and electron conduction becomes large, causing a decrease in capacity and rapid charge / discharge characteristics.
- a negative electrode is formed by bonding a compound having conductivity and suppressing the expansion to the surface of nano-sized Si particles, and granulating the Si particles using a resin such as polyimide imparted with conductivity as a binder.
- a resin such as polyimide imparted with conductivity as a binder.
- Materials have been proposed.
- the compound bonded to the Si surface not only lowers Li ion conduction, but also suppresses the reductive decomposition of the electrolyte during charging, so the electrode expands due to the accumulation of decomposition residue and cycle deterioration cause.
- the present invention has been made in view of the above-described situation, and by covering the surface of the Si negative electrode active material with a Li-containing oxide, reductive decomposition of the electrolytic solution during charging is suppressed, and further, a Li-containing oxide film Li, which exhibits a high discharge capacity exceeding the theoretical capacity of graphite, and excellent initial charge / discharge efficiency and cycle characteristics, by relaxing the charge expansion of the Si negative electrode active material by constraining the surface of the electrode with a conductive binder. It aims at providing the negative electrode material for ion secondary batteries.
- the surface of Si particles as an active material is coated with a thin film of Li-containing oxide containing Li and other specific metal elements, which has a high Li ion conductivity and is stable. It was found that a high discharge capacity and good cycle characteristics can be obtained by constraining the surface with a conductive binder and adjusting the size of the aggregated particles of the active material to a single micron. The reason why high discharge capacity and cycle characteristics can be obtained as described above is that the surface of Si particles as an active material is coated with the above-described Li-containing oxide thin film having high Li ion conductivity and stability.
- the present invention provides the following.
- a Li-containing oxide film having a composition containing Li and at least one metal element M selected from Si, Al, Ti, and Zr, and further the surface of the film
- Li ion secondary characterized in that the average particle diameter of the aggregated particles formed by aggregating the Si particles having the Li-containing oxide film and the conductive binder is 0.5 to 10 ⁇ m.
- Negative electrode material for batteries is 0.5 to 10 ⁇ m.
- the negative electrode material for a Li ion secondary battery of the present invention can sufficiently suppress excessive reductive decomposition of the electrolytic solution due to the active material during charging, and further suppress the expansion of charging by making the conductive binder and aggregate particles fine. Therefore, it exhibits a high discharge capacity exceeding the theoretical charge capacity of graphite and excellent cycle characteristics.
- the negative electrode material for a Li ion secondary battery of the present invention is a contact between an active material and an electrolytic solution by forming a stable and high Li ion conductive Li-containing oxide film on the surface of Si particles as an active material.
- the reductive decomposition of the electrolyte by the active material can be suppressed during charging, and the charging / discharging reaction accompanied by Li ion conduction is not hindered.
- the film thickness is preferably 10 nm or less.
- the film thickness is more preferably 0.5 to 10 nm. If it is thinner than 0.5 nm, the contact between the active material and the electrolytic solution may not be sufficiently prevented.
- the film thickness is more preferably 1 to 5 nm.
- the coating amount by the Li-containing oxide that is, the content of the Li-containing oxide in the negative electrode material for the Li ion secondary battery of the present invention is affected by the specific surface area of the Si particles as the active material.
- the coating amount by the Li-containing oxide that is, the content of the Li-containing oxide in the negative electrode material for the Li ion secondary battery of the present invention is preferably 10% by mass or less.
- the content of the Li-containing oxide in the negative electrode material for a Li-ion secondary battery of the present invention is more than 10% by mass, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may be deteriorated.
- the content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is more preferably 0.5 to 10% by mass.
- the content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is less than 0.5% by mass, the contact between the active material and the electrolytic solution may not be sufficiently prevented.
- the content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is more preferably 1 to 5% by mass.
- the coating film formed on the surface of the Si particles as the active material is made of a Li-containing oxide having a stable and high Li ion conductivity.
- the matrix metal oxide containing Li is at least one selected from SiO 2 , Al 2 O 3 , TiO 2 and ZrO 2 .
- composition is M / Li ⁇ 0.1 in terms of molar ratio, free Li 2 O is likely to be deposited on the Li-containing oxide film and defects may occur, and contact between the active material and the electrolyte may not be sufficiently restricted. There is. If the composition is M / Li> 20 in terms of molar ratio, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may deteriorate.
- the crystal phase of the Li-containing oxide in the present invention is affected by the heat treatment temperature.
- the heat treatment temperature is 200 to 600 ° C.
- crystallization does not proceed and it is amorphous, and when it is 600 ° C. or higher, crystals begin to be formed.
- the Li-containing oxide contains Si as the metal element M, it is amorphous or crystalline phase SiO 2 (tridymite type), Li 4 SiO 4 , Li 2 SiO 3 , Li 2 Si 2. O 5 single phase or mixed phase.
- the Li-containing oxide contains Al as the metal element M, the amorphous or crystalline phase of Al 2 O 3 ( ⁇ type), LiAl 5 O 8 , LiAlO 5 , Li 5 AlO 4 single phase or It becomes a mixed phase.
- the Li-containing oxide contains Ti as the metal element M, the amorphous or crystalline phase of TiO 2 (anatase type, rutile type), Li 4 Ti 5 O 12 , Li 2 TiO 3 single phase or It becomes a mixed phase.
- the Li-containing oxide contains Zr as the metal element M, it is amorphous or crystalline ZrO 2 (monoclinic, tetragonal), Li 2 ZrO 3 , Li 6 Zr 2 O 7 , Li 8 ZrO. 6 mixed or single phase.
- a conductive material may be included in the film.
- a conductive binding material is adhered to the surface of the Li-containing oxide film that covers the active material Si particles.
- the conductive binding material restrains the active material Si particles to relieve the charge expansion, and adjusts the size of the aggregated particles made of the coated Si active material to a fine particle having an average particle diameter of 0.5 to 10 ⁇ m. This disperses the local expansion of the electrode and further imparts electron conduction.
- the average particle diameter of the aggregated particles exceeds 10 ⁇ m, the influence of the charge expansion is locally increased and the deterioration of the electrode is promoted.
- the average particle size is less than 0.5 ⁇ m, the handling of the powder becomes worse.
- the average particle diameter is more preferably in the range of 1 to 5 ⁇ m.
- the particle shape may be any of spherical, flat and crushed, and is not particularly limited.
- the matrix of the binder material having conductivity is at least one selected from carbon, inorganic materials, and resins, and the conductive material that develops conductivity is used by dispersing carbon or graphite in the matrix. Therefore, the conductive binding material contains carbon.
- the carbon which is the matrix of the binding material in the present invention is hard carbon having a low expansion and high capacity
- the inorganic material is glass (eg, sulfide glass Li 10 GeP 2 S 12 ), the crystalline oxide, and the resin is polyimide. Silicone and the like are preferable, but not limited thereto.
- the hard carbon of the carbon matrix can be obtained by heat-treating a precursor such as a phenol resin or an infusible pitch at 600 to 1200 ° C. in an inert atmosphere.
- the inorganic matrix can be obtained by using a mechanochemical method, a sol-gel method or the like as a raw material sulfide or oxide. In the case of the sol-gel method, an intermediate hydroxide is heat-treated at 600 to 1200 ° C. in an inert atmosphere to generate an oxide.
- the resin matrix can be obtained by drying and curing the precursor varnish at 200 to 500 ° C.
- the conductivity imparted to the binder material can be expressed by dispersing a carbon or graphite conductive material in the matrix material, and the shape of the conductive material may be any of a fiber shape, a scale shape, and a tuft shape, and is not particularly limited. .
- Specific examples of the conductive material include carbon nanotubes, scale graphite, earthy graphite, hard carbon, and carbon black.
- the content of the conductive binder of the present invention is preferably 10% by mass or more. If the content of the conductive binder is less than 10% by mass, the charge expansion of the coated Si particles may not be sufficiently relaxed. When the content of the conductive binder is more than 50% by mass, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may be deteriorated.
- the content of the conductive binder of the present invention is more preferably 10 to 50% by mass. When the content of the conductive binder is more than 50% by mass, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may be deteriorated.
- Si particles are used as the active material.
- the Si crystal phase may be either amorphous or crystalline, and is not particularly limited.
- the average particle size of the Si particles is preferably 1 ⁇ m or less. When the average particle diameter exceeds 1 ⁇ m, the influence of the charge expansion is locally increased and the deterioration of the electrode is promoted.
- the average particle size is preferably 0.01 ⁇ m or more.
- the Si particles as the active material have high surface activity, and it is difficult to suppress the reductive decomposition of the electrolytic solution with a film during charging.
- the average particle diameter is more preferably in the range of 0.01 ⁇ m to 0.2 ⁇ m.
- the particle shape may be any of a spherical shape, a flake shape or a fiber shape synthesized by a gas phase method, and a pulverized shape obtained by pulverization in a lump shape, and is not particularly limited.
- Li-containing oxide precursor solution in which a Li compound, which is a precursor of a Li-containing oxide, and a compound of at least one metal element M selected from Si, Al, Ti, and Zr are dispersed, Is an organic solvent, the Li compound serving as the Li source is preferably Li acetate, Li nitrate, Li chloride, etc. dissolved in the organic solvent, and the metal element M compound serving as the metal element M source is an alkoxide dissolved in the organic solvent, Nitrate, chloride and the like are preferred.
- alkoxides those in which the metal element M is Al, Ti, or Zr are easily hydrolyzed and unstable, and thus are preferably stabilized with a chelating agent.
- Chelating agents include, but are not limited to, ethyl acetoacetate, acetylacetone, triatanolamine, and the like.
- organic solvent ethanol, isopropyl alcohol, ethyl acetate, toluene and the like can be used.
- the Li source compound is preferably Li acetate dissolved in water, Li nitrate, Li chloride, or the like, and the metal element M source metal element M source is nitrate, chloride, Oxyacid salts, peroxo acids and the like are preferred.
- the metal element M is Si, an aqueous solution of Li silicate can also be used.
- the carbon raw material that is the matrix of the binding substance in the present invention is preferably a phenol resin, an infusible pitch, or the like that generates hard carbon by heat treatment.
- the phenol resin may be either a resol type or a novolac type.
- the infusibilized pitch can be obtained, for example, by heat treating a coal tar pitch in air at 200 to 600 ° C. and crosslinking the polycyclic aromatic compound in the pitch with oxygen.
- the inorganic matrix material is preferably a sulfide or oxide powder containing a constituent element when prepared by a mechanochemical method, and an alkoxide, nitrate or chloride soluble in a solvent containing the constituent element when prepared by a sol-gel method.
- the resin matrix material can be obtained by dissolving, in a solvent, polyamic acid obtained by polymerizing tetracarboxylic dianhydride and diamine in equimolar amounts.
- a silicone varnish it can be obtained by dissolving a highly branched three-dimensional polymer comprising a siloxane bond having a methyl group, a phenyl group or the like in a solvent.
- Carbon nanotubes, scale graphite, earth graphite, hard carbon, carbon black, and the like can be used as the conductive material that imparts conductivity to the binder.
- the method for producing a negative electrode material for a Li-ion secondary battery according to the present invention includes: a Li compound that is a precursor of a Li-containing oxide; and a compound of at least one metal element M selected from Si, Al, Ti, and Zr.
- Si particles that can be alloyed with Li are added to the dispersed solution (Li-containing oxide precursor solution), dried, and heat-treated in a temperature range of 200 to 1200 ° C., and the surface of the Li-containing oxide film is further electrically conductive. After adhering the binder material or precursor material, heat treatment is performed in a temperature range of 200 to 1200 ° C. to adjust the aggregated particles made of the coated Si particles into fine particles having a size of single micron.
- a solution (Li-containing oxide precursor solution) in which a Li compound that is a precursor of a Li-containing oxide and a compound of at least one metal element M selected from Si, Al, Ti, and Zr is dispersed is a metal element.
- M is Al, Ti, or Zr
- the alkoxide of these elements is stabilized by chelating with an chelating agent: ethyl acetoacetate, acetylacetone, tritananolamine, etc. in an alcohol solvent, and rapid hydrolysis reaction is performed. It is preferable to suppress and improve the film forming property.
- the chelated alkoxide solution further promotes hydrolysis by adding water in order to further improve the film forming property.
- the Li compound is dissolved in a solvent and mixed with the above solution to prepare a solution in which the precursor of the Li-containing oxide is dispersed.
- the metal element M is Si
- the alkoxide is stable, so a chelating agent is unnecessary.
- the Li compound is dissolved in a solvent and mixed with the above solution.
- a solution in which the precursor of the Li-containing oxide is dispersed can be prepared.
- Si particles that can be alloyed with Li are added to the solution containing the precursor of the Li-containing oxide.
- the Si particles may be in the form of a dry powder or a dispersed slurry.
- the dry powder can be obtained by dry pulverizing the raw material Si or removing the solvent after wet pulverization.
- the dispersion slurry can be obtained by wet pulverization.
- the mixed slurry of the Li-containing oxide precursor dispersion and the Si particles removes the solvent and forms a Li-containing oxide precursor film on the surface of the Si particles.
- methods such as spray drying and drying under reduced pressure can be used.
- the Li-containing oxide precursor film is preferably heat-treated at 200 to 1200 ° C. in order to accelerate curing.
- the atmosphere during the heat treatment is preferably a non-oxidizing atmosphere, and a non-reactive gas such as Ar or a low-reactive gas such as N 2 is the main component, and the concentration of the oxidizing gas such as O 2 is more preferably 1000 ppm or less.
- FIG. 2- (1) is an aggregated particle obtained by the above procedure, in which Si particles 20 having a coating of Li-containing oxide 30 on the surface and the conductive binder 40 on the surface of the coating are aggregated.
- a schematic diagram of 10A is shown.
- FIG. 2 (2) shows an aggregated particle obtained by the above-described procedure, in which Si particles 20 having a coating of the Li-containing oxide 30 on the surface and the conductive binder 40 on the surface of the coating are aggregated.
- a schematic diagram of 10B is shown.
- the atmosphere during the heat treatment is preferably a non-oxidizing atmosphere, and a non-reactive gas such as Ar or a low-reactive gas such as N 2 is the main component, and the concentration of the oxidizing gas such as O 2 is more preferably 1000 ppm or less.
- the negative electrode material for Li ion secondary batteries of the present invention is used by mixing with carbon materials such as different types of graphite materials and hard carbon in order to adjust battery characteristics such as capacity, density and efficiency of the electrodes to be produced. Also good.
- the negative electrode for Li ion secondary batteries of this invention is a negative electrode for lithium ion secondary batteries containing said negative electrode material for Li ion secondary batteries.
- the negative electrode for a lithium ion secondary battery of the present invention is produced according to a normal method for forming a negative electrode.
- the binder preferably has chemical and electrochemical stability with respect to the electrolyte.
- fluorine resin powders such as polytetrafluoroethylene and polyvinylidene fluoride, resin powders such as polyethylene and polyvinyl alcohol, Carboxymethylcellulose and the like are used. These can also be used together.
- the binder is usually 1 to 20% by mass in the total amount of the negative electrode mixture.
- the negative electrode material for a Li ion secondary battery of the present invention is adjusted to a desired particle size by classification or the like, and mixed with a binder and a solvent to prepare a slurry negative electrode mixture. That is, the negative electrode material for the Li ion secondary battery of the present invention, a binder and a solvent such as water, isopropylpyrrolidone, N-methylpyrrolidone, dimethylformamide, and the like, using a known stirrer, mixer, kneader, kneader Use to stir and mix to prepare slurry. The slurry is applied to one or both sides of the current collector and dried to obtain a negative electrode in which the negative electrode mixture layer is uniformly and firmly bonded.
- the film thickness of the negative electrode mixture layer is 10 to 200 ⁇ m, preferably 20 to 100 ⁇ m.
- the shape of the current collector used for producing the negative electrode is not particularly limited, but may be a foil shape, a mesh shape, a net shape such as expanded metal, or the like.
- the material of the current collector is preferably copper, stainless steel, nickel or the like, and the thickness of the current collector is usually 5 to 20 ⁇ m.
- the negative electrode for Li ion secondary batteries of this invention may mix carbonaceous materials, such as graphite material and hard carbon, and electrically conductive materials, such as CNT, in the range which does not impair the objective of this invention.
- the Li ion secondary battery of the present invention includes the above-described negative electrode for a Li ion secondary battery, a positive electrode, and a nonaqueous electrolyte, for example, laminated in the order of the negative electrode, the nonaqueous electrolyte, and the positive electrode, and is accommodated in the battery outer packaging material. It is composed by doing.
- a separator is disposed between the negative electrode and the positive electrode.
- the structure, shape, and form of the Li-ion secondary battery of the present invention are not particularly limited, and can be arbitrarily selected from a cylindrical shape, a square shape, a coin shape, a button shape, a laminate shape, and the like depending on the application.
- a battery equipped with means for detecting an increase in the internal pressure of the battery and shutting off the current when an abnormality such as overcharging occurs it is preferable to use a battery equipped with means for detecting an increase in the internal pressure of the battery and shutting off the current when an abnormality such as overcharging occurs.
- the positive electrode is formed, for example, by applying a positive electrode mixture composed of a positive electrode material, a binder, and a solvent to the surface of the current collector.
- a positive electrode active material it is preferable to select a lithium-containing transition metal oxide capable of inserting / extracting a sufficient amount of lithium.
- the lithium-containing transition metal oxide is a composite oxide of lithium and a transition metal, and may contain four or more elements.
- the composite oxide may be used alone or in combination of two or more. Specifically, there are LiCoO 2 , LiNiO 2 , LiMnO 2 , LiNi 0.9 Co 0.1 O 2 , LiNi 0.5 Co 0.5 O 2 , LiFePO 4 and the like.
- the positive electrode active material may be used alone or in combination of two or more.
- various additives such as a conductive agent and a binder can be appropriately used.
- the shape of the current collector is not particularly limited, but a foil shape or a mesh shape such as a mesh or expanded metal is used.
- the material of the current collector is aluminum, stainless steel, nickel or the like, and its thickness is usually 10 to 40 ⁇ m.
- Nonaqueous electrolyte used in Li-ion secondary battery of the present invention, an electrolyte salt used in the conventional non-aqueous electrolyte, LiPF 6, LiBF 4, LiAsF 6, LiClO 4, LiB (C 6 H 5 ), LiCl, LiBr, LiCF 3 SO 3 , LiCH 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiN (CF 3 CH 2 OSO 2 ) 2 , LiN (CF 3 CF 2 OSO 2) 2, LiN ( HCF 2 CF 2 CH 2 OSO 2) 2, LiN ((CF 3) 2 CHOSO 2) 2, LiB [ ⁇ C 6 H 3 (CF 3) 2 ⁇ ] 4, LiAlCl 4, Lithium salts such as LiSiF 6 can be used.
- the electrolyte salt concentration in the electrolytic solution is preferably from 0.1 to 5 mol / L, more preferably from 0.5 to 3.0 mol / L.
- the non-aqueous electrolyte may be a liquid non-aqueous electrolyte or a polymer electrolyte such as a solid electrolyte or a gel electrolyte.
- the non-aqueous electrolyte battery is configured as a so-called Li ion secondary battery
- the non-aqueous electrolyte battery is configured as a polymer electrolyte battery such as a polymer solid electrolyte or a polymer gel electrolyte battery.
- Examples of the electrolyte for preparing the non-aqueous electrolyte include carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate, 1,1- or 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran 2-methyltetrahydrofuran, ⁇ -butyrolactone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, ethers such as anisole and diethyl ether, thioethers such as sulfolane and methylsulfolane, acetonitrile, chloronitrile, propionitrile Nitrile such as trimethyl borate, tetramethyl silicate, nitromethane, dimethylformamide, N-methylpyrrolidone, ethyl acetate, trimethyl orthoformate, nitrobenzene, benzoic chloride , It can be used benzoyl bromide,
- an additive may be added to prevent the electrolytic solution from being reduced and decomposed during charging to deteriorate the battery.
- Known additives include, but are not limited to, fluoroethylene carbonate (FEC), vinylene carbonate (VC), ethylene sulfite (ES), and the like.
- FEC fluoroethylene carbonate
- VC vinylene carbonate
- ES ethylene sulfite
- the addition amount is usually about 0.5 to 10% by mass.
- a separator is disposed between the negative electrode and the positive electrode.
- a separator is not specifically limited, For example, a woven fabric, a nonwoven fabric, a synthetic resin microporous film, etc. can be used.
- a microporous membrane made of synthetic resin is suitable.
- a polyolefin microporous membrane is preferable in terms of thickness, membrane strength, and membrane resistance. Specifically, polyethylene and polypropylene microporous membranes, or microporous membranes combining these are preferred.
- a button type secondary battery for single electrode evaluation composed of (positive electrode) 4 was prepared and evaluated.
- An actual battery can be produced according to a known method based on the concept of the present invention.
- the measurement methods used in the examples are as follows.
- Measurement method (1) Measurement of average particle diameter The average particle diameter was a particle diameter at which the cumulative frequency measured with a laser diffraction particle size meter was 50% by volume.
- Example 1 A first solution is prepared by dissolving 0.02 mol of Al-sec butoxide and 0.02 mol of ethyl acetoacetate in an isopropanol solvent, and then an ethanol solution in which 0.002 mol of acetic acid Li dihydrate is dissolved is used as the first solution. In addition, a second solution was prepared. Next, 29 g of Si particles having an average particle size of 0.15 ⁇ m was added to the second solution, and after removing the solvent, the mixture was baked at 1000 ° C. in a non-oxidizing atmosphere of nitrogen, and Li containing Li as a metal element M and Li containing Al Si particles having an oxide coating film were obtained.
- the above-mentioned coated Si particles were added to an aqueous solution in which a resol-type phenol resin solution (nonvolatile content: 71% by mass), which is a precursor of the conductive binder, was dissolved to prepare a slurry.
- a resol-type phenol resin solution nonvolatile content: 71% by mass
- the phenol resin solution / coated Si particles 1/2 mass ratio.
- the slurry was spray-dried with a spray-drying apparatus, and then fired at 1000 ° C. in a non-oxidizing atmosphere of nitrogen to obtain a spherical dry granulated body.
- Example 2 Spherical dry granules were obtained in the same manner as in Example 1 except that Ti-isopropoxide was used instead of Al-sec butoxide in Example 1.
- Example 3 Spherical dry granules were obtained in the same manner as in Example 1 except that Zr-propoxide was used instead of Al-sec butoxide in Example 1.
- Example 4 A first solution is prepared by dissolving in 0.02 mol of Si-methoxide and an isopropanol solvent, and then an ethanol solution in which 0.002 mol of Lithium acetate dihydrate is dissolved is added to the first solution and refluxed for 2 hours. A spherical dry granulated body was obtained in the same manner as in Example 1 except that it was produced.
- Example 5 As in Example 1, except that a polyamic acid solution in which carbon black was dispersed was used as a precursor of the conductive binder of Example 1 and the heat treatment after spray drying was performed at 300 ° C. using a spray dryer. Thus, a spherical dry granulated body was obtained.
- Example 6 A spherical dry granule was obtained in the same manner as in Example 1 except that the coating amount of the Li-containing oxide was adjusted to 7.0%.
- Example 7 Spherical dry granulated material as in Example 1 except that the spraying conditions of the spray drying apparatus in Example 1 were adjusted so that the average spherical particle size of the obtained spherical dry granulated material was 9.5 ⁇ m. Got.
- Example 1 A spherical dry granulated body was obtained in the same manner as in Example 1 except that Si particles having an average particle diameter of 0.15 ⁇ m that were not coated were used.
- Example 2 A spherical dried granulated body was obtained in the same manner as in Example 1 except that the average particle size of the granulated body spray-dried with a spray drying apparatus was adjusted to 15 ⁇ m.
- Example 3 A spherical dry granule was obtained in the same manner as in Example 5 except that a polyimide resin containing no carbon black was used as the binder.
- the copper foil and the negative electrode mixture layer were punched into a cylindrical shape having a diameter of 15.5 mm and pressed to produce a working electrode (negative electrode) having a negative electrode mixture layer adhered to the copper foil.
- the density of the negative electrode mixture layer was 1.65 g / cm 3 .
- the electrolyte was prepared by dissolving LiPF 6 at a concentration of 1 mol / L in a mixed solvent of 33% by volume of ethylene carbonate (EC) and 67% by volume of methyl ethyl carbonate (MEC) to prepare a non-aqueous electrolyte.
- the prepared non-aqueous electrolyte was impregnated into a 20 ⁇ m thick polypropylene porous separator to produce a separator impregnated with the electrolyte.
- it can produce according to a well-known method based on the concept of this invention.
- FIG. 2 shows a button type secondary battery as a configuration of the evaluation battery.
- the exterior cup 1 and the exterior can 3 were sealed by interposing an insulating gasket 6 at the peripheral portion thereof and caulking both peripheral portions.
- a copper current collector 7 a made of nickel net, a cylindrical counter electrode (positive electrode) 4 made of lithium foil, a separator 5 impregnated with an electrolytic solution, and a negative electrode mixture 2 are attached to the inside of the outer can 3 in that order.
- a battery in which a current collector 7b made of foil is laminated.
- the separator 5 impregnated with the electrolytic solution was sandwiched between the current collector 7b and the working electrode (negative electrode) made of the negative electrode mixture 2, and the counter electrode 4 in close contact with the current collector 7a.
- the current collector 7b is accommodated in the exterior cup 1
- the counter electrode 4 is accommodated in the exterior can 3
- the exterior cup 1 and the exterior can 3 are combined, and an insulating gasket is provided at the peripheral edge between the exterior cup 1 and the exterior can 3. 6 was interposed, and both peripheral portions were caulked and sealed.
- the Li ion secondary battery using the negative electrode material for the Li ion secondary battery of the present invention has a high Li ion conductivity because the coating film has a high Li ion conductivity, and the electrolyte solution is reduced. It can be seen that since the decomposition is suppressed, and the charge expansion of the Si particles themselves and the local charge expansion are suppressed by the single micron aggregate particles by the conductive binder, the capacity retention rate after the cycle is high.
- the uncoated Si particles of Comparative Example 1 have poor cycle characteristics due to large decomposition of the electrolyte. In Comparative Example 2, since the average particle diameter of the aggregated particles is large, the expansion of the electrode film increases and the cycle characteristics are poor. In Comparative Example 3, since the binder material is not conductive, the resistance of electron conduction is large and the capacity is low.
- the surface of Si particles as an active material is coated with a thin film of Li-containing oxide containing Li and other specific metal elements, which has a high Li ion conductivity and is stable.
- a conductive binder By constraining the surface with a conductive binder and adjusting the average particle diameter of the aggregated particles of the active material to a fine particle of 0.5 to 10 ⁇ m, excessive reductive decomposition of the electrolyte by the active material during charging can be achieved.
- a negative electrode material which can be sufficiently suppressed and can suppress charge expansion of Si particles, and thus exhibits a high discharge capacity exceeding the theoretical charge capacity of graphite and excellent cycle characteristics.
- the Li ion secondary battery using the negative electrode material for Li ions of the present invention satisfies the recent demand for higher energy density of the battery, and is useful for downsizing and higher performance of the equipment to be mounted.
- the negative electrode material for Li ions of the present invention can be used for high-performance Li ion secondary batteries ranging from small to large, taking advantage of its characteristics.
Abstract
The present invention provides a negative electrode material for Li ion secondary batteries, which is capable of sufficiently suppressing reductive decomposition of the electrolyte solution by an active material during the charging, while being capable of suppressing expansion of Si particles during the charging, and which enables the achievement of high discharge capacity that is higher than the theoretical capacity of graphite and excellent cycle characteristics. A negative electrode material for Li ion secondary batteries according to the present invention is configured such that aggregated particles have an average particle diameter of 0.5-10 μm, each of said aggregated particles being obtained by forming, on the surfaces of Si particles, a coating film of an Li-containing oxide that is formed from a composition containing Li and at least one metal element M selected from among Si, Al, Ti and Zr, and by having a conductive binder material adhere to the surface of the coating film.
Description
本発明は、Ｌｉと合金化可能なＳｉ粒子表面に、Ｌｉイオン伝導性の金属酸化物を被覆し、さらにＬｉイオン伝導性金属酸化物の被膜表面に導電性の結着物質を有するＬｉイオン二次電池用負極材料に関する。
In the present invention, a Li ion conductive metal oxide is coated on the surface of a Si particle that can be alloyed with Li, and a Li ion conductive metal oxide is coated on the surface of the Li ion conductive metal oxide film. The present invention relates to a negative electrode material for a secondary battery.
Ｌｉイオン二次電池は、高電圧、高エネルギー密度という優れた特性を有するため電子機器の電源として広く普及している。近年、電子機器の小型化および高性能化が進み、Ｌｉイオン二次電池のさらなる高エネルギー密度化に対する要望が高まっている。
現在のＬｉイオン二次電池は、正極にＬｉＣｏＯ2、負極に黒鉛を用いたものが主流である。負極の黒鉛は充放電（charge and discharge）の可逆性に優れるものの、その放電容量はすでに層間化合物（intercalation compound）ＬｉＣ6に相当する理論値３７２ｍＡｈ／ｇに近い値まで到達している。このため、さらなる高エネルギー密度化を達成するためには、黒鉛より放電容量の大きい負極材料を開発する必要がある。
そこで、黒鉛に替わる負極材料として、黒鉛を遥かに凌ぐ放電容量を有するＬｉと合金を形成する活物質としてＳｉ、ＳｉＯが注目されている。Ｓｉ系負極は充電時の合金化に伴う体積膨張が大きいことから劣化しやすく、膨張を低減する対策として粒子の微粒化が有効とされる。しかしながら、微粒化により活物質表面が活性となり、充電時に電解液の還元分解を増進させるため、実用レベルのサイクル特性が得られていない。 Li-ion secondary batteries are widely used as power sources for electronic devices because of their excellent characteristics of high voltage and high energy density. In recent years, downsizing and higher performance of electronic devices have progressed, and there has been an increasing demand for higher energy density of Li-ion secondary batteries.
The current Li ion secondary batteries are mainly those using LiCoO 2 for the positive electrode and graphite for the negative electrode. The graphite of the negative electrode is excellent in reversibility of charge and discharge, but the discharge capacity has already reached a value close to the theoretical value of 372 mAh / g corresponding to the intercalation compound LiC 6 . For this reason, in order to achieve higher energy density, it is necessary to develop a negative electrode material having a discharge capacity larger than that of graphite.
Accordingly, Si and SiO have attracted attention as active materials for forming an alloy with Li having a discharge capacity far exceeding that of graphite as a negative electrode material replacing graphite. Since the Si-based negative electrode has a large volume expansion associated with alloying at the time of charging, it easily deteriorates, and as a measure for reducing the expansion, atomization of particles is effective. However, the active material surface becomes active due to atomization, and the reductive decomposition of the electrolytic solution is promoted at the time of charging. Therefore, the practical cycle characteristics are not obtained.
現在のＬｉイオン二次電池は、正極にＬｉＣｏＯ2、負極に黒鉛を用いたものが主流である。負極の黒鉛は充放電（charge and discharge）の可逆性に優れるものの、その放電容量はすでに層間化合物（intercalation compound）ＬｉＣ6に相当する理論値３７２ｍＡｈ／ｇに近い値まで到達している。このため、さらなる高エネルギー密度化を達成するためには、黒鉛より放電容量の大きい負極材料を開発する必要がある。
そこで、黒鉛に替わる負極材料として、黒鉛を遥かに凌ぐ放電容量を有するＬｉと合金を形成する活物質としてＳｉ、ＳｉＯが注目されている。Ｓｉ系負極は充電時の合金化に伴う体積膨張が大きいことから劣化しやすく、膨張を低減する対策として粒子の微粒化が有効とされる。しかしながら、微粒化により活物質表面が活性となり、充電時に電解液の還元分解を増進させるため、実用レベルのサイクル特性が得られていない。 Li-ion secondary batteries are widely used as power sources for electronic devices because of their excellent characteristics of high voltage and high energy density. In recent years, downsizing and higher performance of electronic devices have progressed, and there has been an increasing demand for higher energy density of Li-ion secondary batteries.
The current Li ion secondary batteries are mainly those using LiCoO 2 for the positive electrode and graphite for the negative electrode. The graphite of the negative electrode is excellent in reversibility of charge and discharge, but the discharge capacity has already reached a value close to the theoretical value of 372 mAh / g corresponding to the intercalation compound LiC 6 . For this reason, in order to achieve higher energy density, it is necessary to develop a negative electrode material having a discharge capacity larger than that of graphite.
Accordingly, Si and SiO have attracted attention as active materials for forming an alloy with Li having a discharge capacity far exceeding that of graphite as a negative electrode material replacing graphite. Since the Si-based negative electrode has a large volume expansion associated with alloying at the time of charging, it easily deteriorates, and as a measure for reducing the expansion, atomization of particles is effective. However, the active material surface becomes active due to atomization, and the reductive decomposition of the electrolytic solution is promoted at the time of charging. Therefore, the practical cycle characteristics are not obtained.
特許文献１では、内部の空隙にＳｉを含有する金属内包中空炭素粒子であって、ＳｉはＣｕまたはＮｉのナノ粒子で被覆されることを特徴とする炭素材料が提案されている。しかしながらＳｉの表面には導電性を付与する金属元素が被覆されているだけで、該金属元素はＬｉイオン伝導を低下させるだけでなく、充電時の電解液の還元分解を抑制することが不十分のため分解物残渣の蓄積により電極が膨脹しサイクル劣化を引き起こす。さらに中空炭素粒子は嵩密度が高くなり負極電極の密度を高めることができない。
Patent Document 1 proposes a carbon material characterized in that it is a metal-containing hollow carbon particle containing Si in an internal void, and Si is coated with Cu or Ni nanoparticles. However, the surface of Si is only coated with a metal element that imparts conductivity. This metal element not only lowers Li ion conduction, but is also insufficient to suppress reductive decomposition of the electrolyte during charging. As a result, accumulation of decomposition product residues causes the electrode to expand and cause cycle deterioration. Further, the hollow carbon particles have a high bulk density and cannot increase the density of the negative electrode.
特許文献２では、ナノサイズのＳｉ粒子をＬｉ含有酸化物で取り囲んだ複合体と炭素材料の混合物を炭素被覆した負極材料が提案されている。しかしながら、本製造方法ではＳｉを取り囲む酸化物量は約３５～８８質量％と過剰のため、Ｌｉイオン伝導および電子伝導の抵抗が大きくなり容量および急速充放電特性の低下を引き起こす。
Patent Document 2 proposes a negative electrode material in which a composite of a nano-sized Si particle surrounded by an Li-containing oxide and a carbon material is coated with carbon. However, in this manufacturing method, the amount of oxide surrounding Si is excessive, about 35 to 88% by mass, so that the resistance of Li ion conduction and electron conduction becomes large, causing a decrease in capacity and rapid charge / discharge characteristics.
特許文献３では、ナノサイズのＳｉ粒子の表面に膨脹を抑制しかつ導電性を有する化合物を接合し、導電性が付与されたポリイミド等の樹脂を結着剤として該Ｓｉ粒子を造粒した負極材料が提案されている。しかしながら、Ｓｉの表面に接合した化合物は、Ｌｉイオン伝導を低下させるだけでなく、充電時の電解液の還元分解を抑制することが不十分なため分解物残渣の蓄積により電極が膨脹しサイクル劣化を引き起こす。
In Patent Document 3, a negative electrode is formed by bonding a compound having conductivity and suppressing the expansion to the surface of nano-sized Si particles, and granulating the Si particles using a resin such as polyimide imparted with conductivity as a binder. Materials have been proposed. However, the compound bonded to the Si surface not only lowers Li ion conduction, but also suppresses the reductive decomposition of the electrolyte during charging, so the electrode expands due to the accumulation of decomposition residue and cycle deterioration cause.
本発明は、上述の状況を鑑みてなされたものであり、Ｓｉ負極活物質の表面にＬｉ含有酸化物を被覆することにより充電時の電解液の還元分解を抑制し、さらにＬｉ含有酸化物被膜の表面を導電性の結着物質で拘束することによりＳｉ負極活物質の充電膨脹を緩和することで、黒鉛の理論容量を超える高い放電容量と、優れた初期充放電効率およびサイクル特性を示すＬｉイオン二次電池用負極材料を提供することを目的とする。
The present invention has been made in view of the above-described situation, and by covering the surface of the Si negative electrode active material with a Li-containing oxide, reductive decomposition of the electrolytic solution during charging is suppressed, and further, a Li-containing oxide film Li, which exhibits a high discharge capacity exceeding the theoretical capacity of graphite, and excellent initial charge / discharge efficiency and cycle characteristics, by relaxing the charge expansion of the Si negative electrode active material by constraining the surface of the electrode with a conductive binder. It aims at providing the negative electrode material for ion secondary batteries.
本発明では、Ｌｉイオン伝導性が高く安定な、Ｌｉおよび他の特定の金属元素を含有するＬｉ含有酸化物の薄膜で活物質であるＳｉ粒子の表面を被覆し、さらにＬｉ含有酸化物被膜の表面を導電性の結着物質で拘束し、前記活物質の集合粒子の大きさをシングルミクロンの細粒に調整することで、高い放電容量と良サイクル特性が得られることを知見した。
上記のように高い放電容量とサイクル特性が得られる理由は、活物質であるＳｉ粒子の表面に、Ｌｉイオン伝導性が高く安定な、上述したＬｉ含有酸化物の薄膜で被覆することで、活物質と電解液の接触を制限し、充電時に活物質による電解液の還元分解を抑制でき、かつＬｉイオン伝導を伴う充放電反応を阻害しないこと、さらにＬｉ含有酸化物被膜の表面に導電性の結着物質で拘束することで前記活物質の充電膨脹が緩和されるとともに、前記活物質の集合粒子の大きさをシングルミクロンの細粒に調整することで電極の局所膨脹が分散するためと考えられる。しかし、本発明はこれらの機序に限定されない。 In the present invention, the surface of Si particles as an active material is coated with a thin film of Li-containing oxide containing Li and other specific metal elements, which has a high Li ion conductivity and is stable. It was found that a high discharge capacity and good cycle characteristics can be obtained by constraining the surface with a conductive binder and adjusting the size of the aggregated particles of the active material to a single micron.
The reason why high discharge capacity and cycle characteristics can be obtained as described above is that the surface of Si particles as an active material is coated with the above-described Li-containing oxide thin film having high Li ion conductivity and stability. Limiting the contact between the substance and the electrolyte, suppressing the reductive decomposition of the electrolyte due to the active material during charging, and not inhibiting the charge / discharge reaction accompanied by Li ion conduction, and the surface of the Li-containing oxide coating The charge expansion of the active material is mitigated by restraining with the binding material, and the local expansion of the electrode is dispersed by adjusting the size of the aggregate particle of the active material to a single micron fine particle. It is done. However, the present invention is not limited to these mechanisms.
上記のように高い放電容量とサイクル特性が得られる理由は、活物質であるＳｉ粒子の表面に、Ｌｉイオン伝導性が高く安定な、上述したＬｉ含有酸化物の薄膜で被覆することで、活物質と電解液の接触を制限し、充電時に活物質による電解液の還元分解を抑制でき、かつＬｉイオン伝導を伴う充放電反応を阻害しないこと、さらにＬｉ含有酸化物被膜の表面に導電性の結着物質で拘束することで前記活物質の充電膨脹が緩和されるとともに、前記活物質の集合粒子の大きさをシングルミクロンの細粒に調整することで電極の局所膨脹が分散するためと考えられる。しかし、本発明はこれらの機序に限定されない。 In the present invention, the surface of Si particles as an active material is coated with a thin film of Li-containing oxide containing Li and other specific metal elements, which has a high Li ion conductivity and is stable. It was found that a high discharge capacity and good cycle characteristics can be obtained by constraining the surface with a conductive binder and adjusting the size of the aggregated particles of the active material to a single micron.
The reason why high discharge capacity and cycle characteristics can be obtained as described above is that the surface of Si particles as an active material is coated with the above-described Li-containing oxide thin film having high Li ion conductivity and stability. Limiting the contact between the substance and the electrolyte, suppressing the reductive decomposition of the electrolyte due to the active material during charging, and not inhibiting the charge / discharge reaction accompanied by Li ion conduction, and the surface of the Li-containing oxide coating The charge expansion of the active material is mitigated by restraining with the binding material, and the local expansion of the electrode is dispersed by adjusting the size of the aggregate particle of the active material to a single micron fine particle. It is done. However, the present invention is not limited to these mechanisms.
すなわち本発明は、以下を提供する。
（１）Ｓｉ粒子表面に、Ｌｉと、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍと、を含有する組成からなるＬｉ含有酸化物の被膜を有し、さらに上記被膜の表面に導電性の結着物質を有するＬｉイオン二次電池用負極材料であって、上記Ｌｉ含有酸化物の含有量が１０質量％以下であり、上記導電性結着物質の含有量が１０質量％以上であり、上記Ｌｉ含有酸化物の被膜および導電性の結着物質を有するＳｉ粒子が集合してなる集合粒子の平均粒子径が０．５～１０μｍであることを特徴とするＬｉイオン二次電池用負極材料。
（２）上記導電性結着物質が、炭素を含有することを特徴とする、上記（１）に記載のＬｉイオン二次電池用負極材料。
（３）上記（１）または（２）に記載の負極材料を含有することを特徴とするＬｉイオン二次電池用負極。
（４）上記（３）に記載のＬｉイオン二次電池用負極を有することを特徴とするＬｉイオン二次電池。 That is, the present invention provides the following.
(1) On the surface of the Si particle, there is a Li-containing oxide film having a composition containing Li and at least one metal element M selected from Si, Al, Ti, and Zr, and further the surface of the film A negative electrode material for a Li ion secondary battery having a conductive binder material, wherein the content of the Li-containing oxide is 10% by mass or less, and the content of the conductive binder material is 10% by mass. Li ion secondary characterized in that the average particle diameter of the aggregated particles formed by aggregating the Si particles having the Li-containing oxide film and the conductive binder is 0.5 to 10 μm. Negative electrode material for batteries.
(2) The negative electrode material for a Li ion secondary battery according to (1), wherein the conductive binder contains carbon.
(3) A negative electrode for a Li-ion secondary battery, comprising the negative electrode material according to (1) or (2).
(4) A Li ion secondary battery comprising the Li ion secondary battery negative electrode according to (3) above.
（１）Ｓｉ粒子表面に、Ｌｉと、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍと、を含有する組成からなるＬｉ含有酸化物の被膜を有し、さらに上記被膜の表面に導電性の結着物質を有するＬｉイオン二次電池用負極材料であって、上記Ｌｉ含有酸化物の含有量が１０質量％以下であり、上記導電性結着物質の含有量が１０質量％以上であり、上記Ｌｉ含有酸化物の被膜および導電性の結着物質を有するＳｉ粒子が集合してなる集合粒子の平均粒子径が０．５～１０μｍであることを特徴とするＬｉイオン二次電池用負極材料。
（２）上記導電性結着物質が、炭素を含有することを特徴とする、上記（１）に記載のＬｉイオン二次電池用負極材料。
（３）上記（１）または（２）に記載の負極材料を含有することを特徴とするＬｉイオン二次電池用負極。
（４）上記（３）に記載のＬｉイオン二次電池用負極を有することを特徴とするＬｉイオン二次電池。 That is, the present invention provides the following.
(1) On the surface of the Si particle, there is a Li-containing oxide film having a composition containing Li and at least one metal element M selected from Si, Al, Ti, and Zr, and further the surface of the film A negative electrode material for a Li ion secondary battery having a conductive binder material, wherein the content of the Li-containing oxide is 10% by mass or less, and the content of the conductive binder material is 10% by mass. Li ion secondary characterized in that the average particle diameter of the aggregated particles formed by aggregating the Si particles having the Li-containing oxide film and the conductive binder is 0.5 to 10 μm. Negative electrode material for batteries.
(2) The negative electrode material for a Li ion secondary battery according to (1), wherein the conductive binder contains carbon.
(3) A negative electrode for a Li-ion secondary battery, comprising the negative electrode material according to (1) or (2).
(4) A Li ion secondary battery comprising the Li ion secondary battery negative electrode according to (3) above.
本発明のＬｉイオン二次電池用負極材料は、充電時に活物質による電解液の過剰な還元分解を充分に抑制でき、さらに導電性結着物質および集合粒子の細粒化により充電膨脹が抑制されるため、黒鉛の理論充電容量を超える高い放電容量、優れたサイクル特性を示す。
The negative electrode material for a Li ion secondary battery of the present invention can sufficiently suppress excessive reductive decomposition of the electrolytic solution due to the active material during charging, and further suppress the expansion of charging by making the conductive binder and aggregate particles fine. Therefore, it exhibits a high discharge capacity exceeding the theoretical charge capacity of graphite and excellent cycle characteristics.
以下、本発明の具体的な実施形態について説明する。
〔本発明のＬｉイオン二次電池用負極材料〕
本発明のＬｉイオン二次電池用負極材料は、活物質であるＳｉ粒子の表面に、安定で高いＬｉイオン伝導性のＬｉ含有酸化物の被膜を形成することで、活物質と電解液の接触を制限して充電時に活物質による電解液の還元分解を抑制でき、かつＬｉイオン伝導を伴う充放電反応を阻害しないため放電容量の低下がなく高電流の充放電反応にも良好な特性を示す。被膜の膜厚は１０ｎｍ以下が好ましい。１０ｎｍを超えるとＬｉイオン伝導および電子伝導の抵抗が増大し電極反応の応答性が悪化するおそれがある。被膜の膜厚は０．５～１０ｎｍがより好ましい。０．５ｎｍよりも薄いと活物質と電解液との接触を十分に防止できなくなるおそれがある。被膜の膜厚は、１～５ｎｍがさらに好ましい。Ｌｉ含有酸化物による被覆量、すなわち、本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量は、活物質であるＳｉ粒子の比表面積に影響される。被膜の膜厚が上記範囲の場合、Ｌｉ含有酸化物による被覆量、すなわち、本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量は、１０質量％以下となることが好ましい。本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量が１０質量％よりも多いとＬｉイオン伝導の抵抗が増大し電極反応の応答性が悪化するおそれがある。本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量は、０．５～１０質量％がより好ましい。本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量が０．５質量％よりも少ないと、活物質と電解液との接触を十分に防止できなくなるおそれがある。本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量は、１～５質量％がさらに好ましい。 Hereinafter, specific embodiments of the present invention will be described.
[Anode Material for Li-ion Secondary Battery of the Present Invention]
The negative electrode material for a Li ion secondary battery of the present invention is a contact between an active material and an electrolytic solution by forming a stable and high Li ion conductive Li-containing oxide film on the surface of Si particles as an active material. The reductive decomposition of the electrolyte by the active material can be suppressed during charging, and the charging / discharging reaction accompanied by Li ion conduction is not hindered. . The film thickness is preferably 10 nm or less. If it exceeds 10 nm, the resistance of Li ion conduction and electron conduction may increase, and the responsiveness of the electrode reaction may be deteriorated. The film thickness is more preferably 0.5 to 10 nm. If it is thinner than 0.5 nm, the contact between the active material and the electrolytic solution may not be sufficiently prevented. The film thickness is more preferably 1 to 5 nm. The coating amount by the Li-containing oxide, that is, the content of the Li-containing oxide in the negative electrode material for the Li ion secondary battery of the present invention is affected by the specific surface area of the Si particles as the active material. When the film thickness is in the above range, the coating amount by the Li-containing oxide, that is, the content of the Li-containing oxide in the negative electrode material for the Li ion secondary battery of the present invention is preferably 10% by mass or less. . When the content of the Li-containing oxide in the negative electrode material for a Li-ion secondary battery of the present invention is more than 10% by mass, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may be deteriorated. The content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is more preferably 0.5 to 10% by mass. When the content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is less than 0.5% by mass, the contact between the active material and the electrolytic solution may not be sufficiently prevented. The content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is more preferably 1 to 5% by mass.
〔本発明のＬｉイオン二次電池用負極材料〕
本発明のＬｉイオン二次電池用負極材料は、活物質であるＳｉ粒子の表面に、安定で高いＬｉイオン伝導性のＬｉ含有酸化物の被膜を形成することで、活物質と電解液の接触を制限して充電時に活物質による電解液の還元分解を抑制でき、かつＬｉイオン伝導を伴う充放電反応を阻害しないため放電容量の低下がなく高電流の充放電反応にも良好な特性を示す。被膜の膜厚は１０ｎｍ以下が好ましい。１０ｎｍを超えるとＬｉイオン伝導および電子伝導の抵抗が増大し電極反応の応答性が悪化するおそれがある。被膜の膜厚は０．５～１０ｎｍがより好ましい。０．５ｎｍよりも薄いと活物質と電解液との接触を十分に防止できなくなるおそれがある。被膜の膜厚は、１～５ｎｍがさらに好ましい。Ｌｉ含有酸化物による被覆量、すなわち、本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量は、活物質であるＳｉ粒子の比表面積に影響される。被膜の膜厚が上記範囲の場合、Ｌｉ含有酸化物による被覆量、すなわち、本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量は、１０質量％以下となることが好ましい。本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量が１０質量％よりも多いとＬｉイオン伝導の抵抗が増大し電極反応の応答性が悪化するおそれがある。本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量は、０．５～１０質量％がより好ましい。本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量が０．５質量％よりも少ないと、活物質と電解液との接触を十分に防止できなくなるおそれがある。本発明のＬｉイオン二次電池用負極材料におけるＬｉ含有酸化物の含有量は、１～５質量％がさらに好ましい。 Hereinafter, specific embodiments of the present invention will be described.
[Anode Material for Li-ion Secondary Battery of the Present Invention]
The negative electrode material for a Li ion secondary battery of the present invention is a contact between an active material and an electrolytic solution by forming a stable and high Li ion conductive Li-containing oxide film on the surface of Si particles as an active material. The reductive decomposition of the electrolyte by the active material can be suppressed during charging, and the charging / discharging reaction accompanied by Li ion conduction is not hindered. . The film thickness is preferably 10 nm or less. If it exceeds 10 nm, the resistance of Li ion conduction and electron conduction may increase, and the responsiveness of the electrode reaction may be deteriorated. The film thickness is more preferably 0.5 to 10 nm. If it is thinner than 0.5 nm, the contact between the active material and the electrolytic solution may not be sufficiently prevented. The film thickness is more preferably 1 to 5 nm. The coating amount by the Li-containing oxide, that is, the content of the Li-containing oxide in the negative electrode material for the Li ion secondary battery of the present invention is affected by the specific surface area of the Si particles as the active material. When the film thickness is in the above range, the coating amount by the Li-containing oxide, that is, the content of the Li-containing oxide in the negative electrode material for the Li ion secondary battery of the present invention is preferably 10% by mass or less. . When the content of the Li-containing oxide in the negative electrode material for a Li-ion secondary battery of the present invention is more than 10% by mass, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may be deteriorated. The content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is more preferably 0.5 to 10% by mass. When the content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is less than 0.5% by mass, the contact between the active material and the electrolytic solution may not be sufficiently prevented. The content of the Li-containing oxide in the negative electrode material for a Li ion secondary battery of the present invention is more preferably 1 to 5% by mass.
本発明のＬｉイオン二次電池用負極材料において、活物質であるＳｉ粒子の表面に形成される被膜は、安定で高いＬｉイオン伝導性を有するＬｉ含有酸化物からなる。Ｌｉを含有させるマトリックスの金属酸化物は、ＳｉＯ2、Ａｌ2Ｏ3、ＴｉＯ2およびＺｒＯ2から選ばれる１種以上である。
本発明におけるＬｉ含有酸化物は、Ｌｉおよび金属元素Ｍがｍｏｌ比でＭ／Ｌｉ＝０．１～２０の組成が好ましく、０．２～１０がより好ましい。ｍｏｌ比でＭ／Ｌｉ＜０．１の組成だと、Ｌｉ含有酸化物の被膜にフリーのＬｉ2Ｏが析出して欠陥を生じやすく、活物質と電解液の接触を十分に制限できない可能性がある。ｍｏｌ比でＭ／Ｌｉ＞２０の組成だとＬｉイオン伝導の抵抗が増大し電極反応の応答性が悪化するおそれがある。 In the negative electrode material for a Li ion secondary battery of the present invention, the coating film formed on the surface of the Si particles as the active material is made of a Li-containing oxide having a stable and high Li ion conductivity. The matrix metal oxide containing Li is at least one selected from SiO 2 , Al 2 O 3 , TiO 2 and ZrO 2 .
The Li-containing oxide in the present invention preferably has a composition in which Li and the metal element M have a molar ratio of M / Li = 0.1 to 20, and more preferably 0.2 to 10. If the composition is M / Li <0.1 in terms of molar ratio, free Li 2 O is likely to be deposited on the Li-containing oxide film and defects may occur, and contact between the active material and the electrolyte may not be sufficiently restricted. There is. If the composition is M / Li> 20 in terms of molar ratio, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may deteriorate.
本発明におけるＬｉ含有酸化物は、Ｌｉおよび金属元素Ｍがｍｏｌ比でＭ／Ｌｉ＝０．１～２０の組成が好ましく、０．２～１０がより好ましい。ｍｏｌ比でＭ／Ｌｉ＜０．１の組成だと、Ｌｉ含有酸化物の被膜にフリーのＬｉ2Ｏが析出して欠陥を生じやすく、活物質と電解液の接触を十分に制限できない可能性がある。ｍｏｌ比でＭ／Ｌｉ＞２０の組成だとＬｉイオン伝導の抵抗が増大し電極反応の応答性が悪化するおそれがある。 In the negative electrode material for a Li ion secondary battery of the present invention, the coating film formed on the surface of the Si particles as the active material is made of a Li-containing oxide having a stable and high Li ion conductivity. The matrix metal oxide containing Li is at least one selected from SiO 2 , Al 2 O 3 , TiO 2 and ZrO 2 .
The Li-containing oxide in the present invention preferably has a composition in which Li and the metal element M have a molar ratio of M / Li = 0.1 to 20, and more preferably 0.2 to 10. If the composition is M / Li <0.1 in terms of molar ratio, free Li 2 O is likely to be deposited on the Li-containing oxide film and defects may occur, and contact between the active material and the electrolyte may not be sufficiently restricted. There is. If the composition is M / Li> 20 in terms of molar ratio, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may deteriorate.
本発明におけるＬｉ含有酸化物の結晶相は熱処理温度の影響を受ける。一般に熱処理温度が２００～６００℃では結晶化が進まず非晶質であり、６００℃以上で結晶が生成し始める。具体的には、Ｌｉ含有酸化物が金属元素ＭとしてＳｉを含有する場合は、非晶質、または結晶相のＳｉＯ2（トリジマイト型）、Ｌｉ4ＳｉＯ4、Ｌｉ2ＳｉＯ3、Ｌｉ2Ｓｉ2Ｏ5の単一相または混合相となる。Ｌｉ含有酸化物が金属元素ＭとしてＡｌを含有する場合は、非晶質、または結晶相のＡｌ2Ｏ3（γ型）、ＬｉＡｌ5Ｏ8、ＬｉＡｌＯ5、Ｌｉ5ＡｌＯ4の単一相または混合相となる。Ｌｉ含有酸化物が金属元素ＭとしてＴｉを含有する場合は、非晶質、または結晶相のＴｉＯ2（アナターゼ型、ルチル型）、Ｌｉ4Ｔｉ5Ｏ12、Ｌｉ2ＴｉＯ3の単一相または混合相となる。Ｌｉ含有酸化物が金属元素ＭとしてＺｒを含有する場合は、非晶質、または結晶相のＺｒＯ2（単斜晶、正方晶）、Ｌｉ2ＺｒＯ3、Ｌｉ6Ｚｒ2Ｏ7、Ｌｉ8ＺｒＯ6の混合相または単一相となる。
The crystal phase of the Li-containing oxide in the present invention is affected by the heat treatment temperature. In general, when the heat treatment temperature is 200 to 600 ° C., crystallization does not proceed and it is amorphous, and when it is 600 ° C. or higher, crystals begin to be formed. Specifically, when the Li-containing oxide contains Si as the metal element M, it is amorphous or crystalline phase SiO 2 (tridymite type), Li 4 SiO 4 , Li 2 SiO 3 , Li 2 Si 2. O 5 single phase or mixed phase. When the Li-containing oxide contains Al as the metal element M, the amorphous or crystalline phase of Al 2 O 3 (γ type), LiAl 5 O 8 , LiAlO 5 , Li 5 AlO 4 single phase or It becomes a mixed phase. When the Li-containing oxide contains Ti as the metal element M, the amorphous or crystalline phase of TiO 2 (anatase type, rutile type), Li 4 Ti 5 O 12 , Li 2 TiO 3 single phase or It becomes a mixed phase. When the Li-containing oxide contains Zr as the metal element M, it is amorphous or crystalline ZrO 2 (monoclinic, tetragonal), Li 2 ZrO 3 , Li 6 Zr 2 O 7 , Li 8 ZrO. 6 mixed or single phase.
また本発明におけるＬｉ含有酸化物の被膜に導電性を付与する必要がある場合は、該被膜に導電材を含有させてもよい。
In addition, when it is necessary to impart conductivity to the Li-containing oxide film in the present invention, a conductive material may be included in the film.
本発明のＬｉイオン二次電池用負極材料において、活物質Ｓｉ粒子に被覆するＬｉ含有酸化物被膜の表面には、導電性を有する結着物質を付着させる。該導電性結着物質は、活物質のＳｉ粒子を拘束して充電膨脹を緩和させ、上記被覆Ｓｉ活物質からなる集合粒子の大きさを平均粒子径が０．５～１０μｍの細粒に調整することで電極の局所膨脹を分散させ、さらに電子伝導を付与する。上記集合粒子の平均粒子径は１０μｍを超えると充電膨張の影響が局所的に大きくなり電極の劣化が増進する。平均粒子径が０．５μｍ未満であると、粉体のハンドリングが悪くなる。平均粒子径は、１～５μｍの範囲であることがより好ましい。粒子形状については、球状、扁平状、および破砕状の何れでもよく、特に限定されない。
In the negative electrode material for a Li ion secondary battery of the present invention, a conductive binding material is adhered to the surface of the Li-containing oxide film that covers the active material Si particles. The conductive binding material restrains the active material Si particles to relieve the charge expansion, and adjusts the size of the aggregated particles made of the coated Si active material to a fine particle having an average particle diameter of 0.5 to 10 μm. This disperses the local expansion of the electrode and further imparts electron conduction. When the average particle diameter of the aggregated particles exceeds 10 μm, the influence of the charge expansion is locally increased and the deterioration of the electrode is promoted. When the average particle size is less than 0.5 μm, the handling of the powder becomes worse. The average particle diameter is more preferably in the range of 1 to 5 μm. The particle shape may be any of spherical, flat and crushed, and is not particularly limited.
導電性を有する結着物質のマトリックスは、炭素、無機物質、樹脂から選ばれる１種以上であり、導電性を発現させる導電材は、炭素または黒鉛を前記マトリックスに分散して使用する。したがって、導電性を有する結着物質は炭素を含有する。
The matrix of the binder material having conductivity is at least one selected from carbon, inorganic materials, and resins, and the conductive material that develops conductivity is used by dispersing carbon or graphite in the matrix. Therefore, the conductive binding material contains carbon.
本発明における結着物質のマトリックスである炭素は、低膨張で高容量のハードカーボン、無機物質としては、ガラス（例：硫化物ガラス Ｌｉ10ＧｅＰ2Ｓ12）、結晶性酸化物、樹脂としてポリイミド、シリコーンなどが好ましいが、これらに限定されない。炭素マトリックスのハードカーボンは、フェノール樹脂、不融化ピッチなどの前駆物質を不活性雰囲気下６００～１２００℃で熱処理して得ることができる。無機マトリックスは、原料の硫化物、酸化物などをメカノケミカル法、ゾルゲル法等で得ることができる。ゾルゲル法の場合は、中間体の水酸化物を不活性雰囲気下６００～１２００℃で熱処理して酸化物を生成させる。樹脂マトリックスは、前駆体のワニスを乾燥後２００～５００℃で熱硬化して得ることができる。
The carbon which is the matrix of the binding material in the present invention is hard carbon having a low expansion and high capacity, the inorganic material is glass (eg, sulfide glass Li 10 GeP 2 S 12 ), the crystalline oxide, and the resin is polyimide. Silicone and the like are preferable, but not limited thereto. The hard carbon of the carbon matrix can be obtained by heat-treating a precursor such as a phenol resin or an infusible pitch at 600 to 1200 ° C. in an inert atmosphere. The inorganic matrix can be obtained by using a mechanochemical method, a sol-gel method or the like as a raw material sulfide or oxide. In the case of the sol-gel method, an intermediate hydroxide is heat-treated at 600 to 1200 ° C. in an inert atmosphere to generate an oxide. The resin matrix can be obtained by drying and curing the precursor varnish at 200 to 500 ° C.
結着物質への導電性付与は、前記マトリックス物質に炭素または黒鉛の導電材を分散することで発現でき、導電材の形状は、繊維状、鱗片状、房状の何れでもよく、特に限定されない。具体的な導電材としては、カーボンナノチューブ、鱗片黒鉛、土状黒鉛、ハードカーボン、カーボンブラックなどである。
The conductivity imparted to the binder material can be expressed by dispersing a carbon or graphite conductive material in the matrix material, and the shape of the conductive material may be any of a fiber shape, a scale shape, and a tuft shape, and is not particularly limited. . Specific examples of the conductive material include carbon nanotubes, scale graphite, earthy graphite, hard carbon, and carbon black.
本発明の導電性結着物質の含有量は、１０質量％以上となることが好ましい。導電性結着物質の含有量が１０質量％よりも少ないと、被覆Ｓｉ粒子の充電膨脹を十分に緩和することができないおそれがある。導電性結着物質の含有量が５０質量％よりも多いとＬｉイオン伝導の抵抗が増大し電極反応の応答性が悪化するおそれがある。本発明の導電性結着物質の含有量は、１０～５０質量％となることがより好ましい。導電性結着物質の含有量が５０質量％よりも多いとＬｉイオン伝導の抵抗が増大し電極反応の応答性が悪化するおそれがある。
The content of the conductive binder of the present invention is preferably 10% by mass or more. If the content of the conductive binder is less than 10% by mass, the charge expansion of the coated Si particles may not be sufficiently relaxed. When the content of the conductive binder is more than 50% by mass, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may be deteriorated. The content of the conductive binder of the present invention is more preferably 10 to 50% by mass. When the content of the conductive binder is more than 50% by mass, the resistance of Li ion conduction increases and the responsiveness of the electrode reaction may be deteriorated.
〔本発明のＬｉイオン二次電池用負極材料の原料〕
＜活物質＞
本発明のＬｉイオン二次電池用負極材料では、活物質として、Ｓｉ粒子を用いる。Ｓｉ結晶相は非晶質または結晶質のどちらでもよく、特に限定されない。
Ｓｉ粒子の平均粒子径は１μｍ以下であることが好ましい。平均粒子径が１μｍを超えると充電膨張の影響が局所的に大きくなり電極の劣化が増進する。平均粒子径は、０．０１μｍ以上であることが好ましい。平均粒子径が０．０１μｍ未満であると、活物質であるＳｉ粒子は表面の活性が高く充電時に電解液の還元分解を被膜で抑制することが難しい。平均粒子径は、０．０１μｍ～０．２μｍの範囲であることがより好ましい。粒子形状については、気相法で合成される球状、薄片状または繊維状、および塊状の粉砕で得られる破砕状の何れでもよく、特に限定されない。 [Raw material of negative electrode material for Li ion secondary battery of the present invention]
<Active material>
In the negative electrode material for a Li ion secondary battery of the present invention, Si particles are used as the active material. The Si crystal phase may be either amorphous or crystalline, and is not particularly limited.
The average particle size of the Si particles is preferably 1 μm or less. When the average particle diameter exceeds 1 μm, the influence of the charge expansion is locally increased and the deterioration of the electrode is promoted. The average particle size is preferably 0.01 μm or more. When the average particle size is less than 0.01 μm, the Si particles as the active material have high surface activity, and it is difficult to suppress the reductive decomposition of the electrolytic solution with a film during charging. The average particle diameter is more preferably in the range of 0.01 μm to 0.2 μm. The particle shape may be any of a spherical shape, a flake shape or a fiber shape synthesized by a gas phase method, and a pulverized shape obtained by pulverization in a lump shape, and is not particularly limited.
＜活物質＞
本発明のＬｉイオン二次電池用負極材料では、活物質として、Ｓｉ粒子を用いる。Ｓｉ結晶相は非晶質または結晶質のどちらでもよく、特に限定されない。
Ｓｉ粒子の平均粒子径は１μｍ以下であることが好ましい。平均粒子径が１μｍを超えると充電膨張の影響が局所的に大きくなり電極の劣化が増進する。平均粒子径は、０．０１μｍ以上であることが好ましい。平均粒子径が０．０１μｍ未満であると、活物質であるＳｉ粒子は表面の活性が高く充電時に電解液の還元分解を被膜で抑制することが難しい。平均粒子径は、０．０１μｍ～０．２μｍの範囲であることがより好ましい。粒子形状については、気相法で合成される球状、薄片状または繊維状、および塊状の粉砕で得られる破砕状の何れでもよく、特に限定されない。 [Raw material of negative electrode material for Li ion secondary battery of the present invention]
<Active material>
In the negative electrode material for a Li ion secondary battery of the present invention, Si particles are used as the active material. The Si crystal phase may be either amorphous or crystalline, and is not particularly limited.
The average particle size of the Si particles is preferably 1 μm or less. When the average particle diameter exceeds 1 μm, the influence of the charge expansion is locally increased and the deterioration of the electrode is promoted. The average particle size is preferably 0.01 μm or more. When the average particle size is less than 0.01 μm, the Si particles as the active material have high surface activity, and it is difficult to suppress the reductive decomposition of the electrolytic solution with a film during charging. The average particle diameter is more preferably in the range of 0.01 μm to 0.2 μm. The particle shape may be any of a spherical shape, a flake shape or a fiber shape synthesized by a gas phase method, and a pulverized shape obtained by pulverization in a lump shape, and is not particularly limited.
＜Ｌｉ含有酸化物前駆体溶液＞
Ｌｉ含有酸化物の前駆物質である、Ｌｉ化合物と、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍの化合物と、が分散した溶液（Ｌｉ含有酸化物前駆体溶液）において、溶媒が有機溶剤の場合、Ｌｉ源となるＬｉ化合物は有機溶剤に溶解する酢酸Ｌｉ、硝酸Ｌｉ、塩化Ｌｉ等が好ましく、金属元素Ｍ源となる金属元素Ｍの化合物は、有機溶剤に溶解するアルコキシド、硝酸塩、塩化物等が好ましい。アルコキシドのうち、金属元素ＭがＡｌ、Ｔｉ、Ｚｒのものは加水分解しやすく不安定なため、キレート剤で安定化させることが好ましい。キレート剤には、アセト酢酸エチル、アセチルアセトン、トリアタノールアミン等があるが、これらに限定されない。有機溶剤はエタノール、イソプロピルアルコール、酢酸エチル、トルエンなどを使用できる。溶媒が水の場合、Ｌｉ源となる化合物は水に溶解する酢酸Ｌｉ、硝酸Ｌｉ、塩化Ｌｉ等が好ましく、金属元素Ｍ源となる金属元素Ｍの化合物は、水に溶解する硝酸塩、塩化物、オキシ酸塩、ペルオキソ酸等が好ましい。金属元素ＭがＳｉの場合はケイ酸Ｌｉ水溶液を使用することもできる。 <Li-containing oxide precursor solution>
In a solution (Li-containing oxide precursor solution) in which a Li compound, which is a precursor of a Li-containing oxide, and a compound of at least one metal element M selected from Si, Al, Ti, and Zr are dispersed, Is an organic solvent, the Li compound serving as the Li source is preferably Li acetate, Li nitrate, Li chloride, etc. dissolved in the organic solvent, and the metal element M compound serving as the metal element M source is an alkoxide dissolved in the organic solvent, Nitrate, chloride and the like are preferred. Among alkoxides, those in which the metal element M is Al, Ti, or Zr are easily hydrolyzed and unstable, and thus are preferably stabilized with a chelating agent. Chelating agents include, but are not limited to, ethyl acetoacetate, acetylacetone, triatanolamine, and the like. As the organic solvent, ethanol, isopropyl alcohol, ethyl acetate, toluene and the like can be used. When the solvent is water, the Li source compound is preferably Li acetate dissolved in water, Li nitrate, Li chloride, or the like, and the metal element M source metal element M source is nitrate, chloride, Oxyacid salts, peroxo acids and the like are preferred. When the metal element M is Si, an aqueous solution of Li silicate can also be used.
Ｌｉ含有酸化物の前駆物質である、Ｌｉ化合物と、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍの化合物と、が分散した溶液（Ｌｉ含有酸化物前駆体溶液）において、溶媒が有機溶剤の場合、Ｌｉ源となるＬｉ化合物は有機溶剤に溶解する酢酸Ｌｉ、硝酸Ｌｉ、塩化Ｌｉ等が好ましく、金属元素Ｍ源となる金属元素Ｍの化合物は、有機溶剤に溶解するアルコキシド、硝酸塩、塩化物等が好ましい。アルコキシドのうち、金属元素ＭがＡｌ、Ｔｉ、Ｚｒのものは加水分解しやすく不安定なため、キレート剤で安定化させることが好ましい。キレート剤には、アセト酢酸エチル、アセチルアセトン、トリアタノールアミン等があるが、これらに限定されない。有機溶剤はエタノール、イソプロピルアルコール、酢酸エチル、トルエンなどを使用できる。溶媒が水の場合、Ｌｉ源となる化合物は水に溶解する酢酸Ｌｉ、硝酸Ｌｉ、塩化Ｌｉ等が好ましく、金属元素Ｍ源となる金属元素Ｍの化合物は、水に溶解する硝酸塩、塩化物、オキシ酸塩、ペルオキソ酸等が好ましい。金属元素ＭがＳｉの場合はケイ酸Ｌｉ水溶液を使用することもできる。 <Li-containing oxide precursor solution>
In a solution (Li-containing oxide precursor solution) in which a Li compound, which is a precursor of a Li-containing oxide, and a compound of at least one metal element M selected from Si, Al, Ti, and Zr are dispersed, Is an organic solvent, the Li compound serving as the Li source is preferably Li acetate, Li nitrate, Li chloride, etc. dissolved in the organic solvent, and the metal element M compound serving as the metal element M source is an alkoxide dissolved in the organic solvent, Nitrate, chloride and the like are preferred. Among alkoxides, those in which the metal element M is Al, Ti, or Zr are easily hydrolyzed and unstable, and thus are preferably stabilized with a chelating agent. Chelating agents include, but are not limited to, ethyl acetoacetate, acetylacetone, triatanolamine, and the like. As the organic solvent, ethanol, isopropyl alcohol, ethyl acetate, toluene and the like can be used. When the solvent is water, the Li source compound is preferably Li acetate dissolved in water, Li nitrate, Li chloride, or the like, and the metal element M source metal element M source is nitrate, chloride, Oxyacid salts, peroxo acids and the like are preferred. When the metal element M is Si, an aqueous solution of Li silicate can also be used.
＜導電性結着物質＞
本発明における結着物質のマトリックスである炭素の原料は、熱処理でハードカーボンを生成する、フェノール樹脂、不融化ピッチなどが好ましい。フェノール樹脂は、レゾール型、ノボラック型の何れでも良い。不融化ピッチは、例えばコールタールピッチを空気中２００～６００℃で熱処理し、ピッチ中の多環芳香族化合物を酸素で架橋して得ることができる。無機マトリックスの原料は、メカノケミカル法で作製する場合は構成元素を含む硫化物、酸化物などの粉末が好ましく、ゾルゲル法で作製する場合は構成元素を含む溶媒に可溶なアルコキシド、硝酸塩、塩化物等の化合物が好ましい。樹脂マトリックスの原料は、ポリイミドワニスの場合、テトラカルボン酸二無水物とジアミンを原料に等モルで重合させたポリアミド酸を溶媒に溶解して得ることができる。シリコーンワニスの場合、メチル基、フェニル基等を有するシロキサン結合からなる分岐度の高い三次元ポリマーを溶媒に溶解して得ることができる。
結着物質に導電性を付与する導電材は、カーボンナノチューブ、鱗片黒鉛、土状黒鉛、ハードカーボン、カーボンブラックなどを使用することができる。 <Conductive binder>
The carbon raw material that is the matrix of the binding substance in the present invention is preferably a phenol resin, an infusible pitch, or the like that generates hard carbon by heat treatment. The phenol resin may be either a resol type or a novolac type. The infusibilized pitch can be obtained, for example, by heat treating a coal tar pitch in air at 200 to 600 ° C. and crosslinking the polycyclic aromatic compound in the pitch with oxygen. The inorganic matrix material is preferably a sulfide or oxide powder containing a constituent element when prepared by a mechanochemical method, and an alkoxide, nitrate or chloride soluble in a solvent containing the constituent element when prepared by a sol-gel method. Compounds such as products are preferred. In the case of a polyimide varnish, the resin matrix material can be obtained by dissolving, in a solvent, polyamic acid obtained by polymerizing tetracarboxylic dianhydride and diamine in equimolar amounts. In the case of a silicone varnish, it can be obtained by dissolving a highly branched three-dimensional polymer comprising a siloxane bond having a methyl group, a phenyl group or the like in a solvent.
Carbon nanotubes, scale graphite, earth graphite, hard carbon, carbon black, and the like can be used as the conductive material that imparts conductivity to the binder.
本発明における結着物質のマトリックスである炭素の原料は、熱処理でハードカーボンを生成する、フェノール樹脂、不融化ピッチなどが好ましい。フェノール樹脂は、レゾール型、ノボラック型の何れでも良い。不融化ピッチは、例えばコールタールピッチを空気中２００～６００℃で熱処理し、ピッチ中の多環芳香族化合物を酸素で架橋して得ることができる。無機マトリックスの原料は、メカノケミカル法で作製する場合は構成元素を含む硫化物、酸化物などの粉末が好ましく、ゾルゲル法で作製する場合は構成元素を含む溶媒に可溶なアルコキシド、硝酸塩、塩化物等の化合物が好ましい。樹脂マトリックスの原料は、ポリイミドワニスの場合、テトラカルボン酸二無水物とジアミンを原料に等モルで重合させたポリアミド酸を溶媒に溶解して得ることができる。シリコーンワニスの場合、メチル基、フェニル基等を有するシロキサン結合からなる分岐度の高い三次元ポリマーを溶媒に溶解して得ることができる。
結着物質に導電性を付与する導電材は、カーボンナノチューブ、鱗片黒鉛、土状黒鉛、ハードカーボン、カーボンブラックなどを使用することができる。 <Conductive binder>
The carbon raw material that is the matrix of the binding substance in the present invention is preferably a phenol resin, an infusible pitch, or the like that generates hard carbon by heat treatment. The phenol resin may be either a resol type or a novolac type. The infusibilized pitch can be obtained, for example, by heat treating a coal tar pitch in air at 200 to 600 ° C. and crosslinking the polycyclic aromatic compound in the pitch with oxygen. The inorganic matrix material is preferably a sulfide or oxide powder containing a constituent element when prepared by a mechanochemical method, and an alkoxide, nitrate or chloride soluble in a solvent containing the constituent element when prepared by a sol-gel method. Compounds such as products are preferred. In the case of a polyimide varnish, the resin matrix material can be obtained by dissolving, in a solvent, polyamic acid obtained by polymerizing tetracarboxylic dianhydride and diamine in equimolar amounts. In the case of a silicone varnish, it can be obtained by dissolving a highly branched three-dimensional polymer comprising a siloxane bond having a methyl group, a phenyl group or the like in a solvent.
Carbon nanotubes, scale graphite, earth graphite, hard carbon, carbon black, and the like can be used as the conductive material that imparts conductivity to the binder.
〔本発明のＬｉイオン二次電池用負極材料の製造方法〕
本発明のＬｉイオン二次電池用負極材料の製造方法は、Ｌｉ含有酸化物の前駆物質であるＬｉ化合物と、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍの化合物と、が分散した溶液（Ｌｉ含有酸化物前駆体溶液）に、Ｌｉと合金化可能なＳｉ粒子を加えて、乾燥後２００～１２００℃の温度範囲で熱処理し、さらにＬｉ含有酸化物被膜の表面に導電性の結着物質または前駆物質を付着させたあと２００～１２００℃の温度範囲で熱処理し、被覆Ｓｉ粒子からなる集合粒子をシングルミクロンの大きさの細粒に調整する。 [Method for producing negative electrode material for Li ion secondary battery of the present invention]
The method for producing a negative electrode material for a Li-ion secondary battery according to the present invention includes: a Li compound that is a precursor of a Li-containing oxide; and a compound of at least one metal element M selected from Si, Al, Ti, and Zr. Si particles that can be alloyed with Li are added to the dispersed solution (Li-containing oxide precursor solution), dried, and heat-treated in a temperature range of 200 to 1200 ° C., and the surface of the Li-containing oxide film is further electrically conductive. After adhering the binder material or precursor material, heat treatment is performed in a temperature range of 200 to 1200 ° C. to adjust the aggregated particles made of the coated Si particles into fine particles having a size of single micron.
本発明のＬｉイオン二次電池用負極材料の製造方法は、Ｌｉ含有酸化物の前駆物質であるＬｉ化合物と、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍの化合物と、が分散した溶液（Ｌｉ含有酸化物前駆体溶液）に、Ｌｉと合金化可能なＳｉ粒子を加えて、乾燥後２００～１２００℃の温度範囲で熱処理し、さらにＬｉ含有酸化物被膜の表面に導電性の結着物質または前駆物質を付着させたあと２００～１２００℃の温度範囲で熱処理し、被覆Ｓｉ粒子からなる集合粒子をシングルミクロンの大きさの細粒に調整する。 [Method for producing negative electrode material for Li ion secondary battery of the present invention]
The method for producing a negative electrode material for a Li-ion secondary battery according to the present invention includes: a Li compound that is a precursor of a Li-containing oxide; and a compound of at least one metal element M selected from Si, Al, Ti, and Zr. Si particles that can be alloyed with Li are added to the dispersed solution (Li-containing oxide precursor solution), dried, and heat-treated in a temperature range of 200 to 1200 ° C., and the surface of the Li-containing oxide film is further electrically conductive. After adhering the binder material or precursor material, heat treatment is performed in a temperature range of 200 to 1200 ° C. to adjust the aggregated particles made of the coated Si particles into fine particles having a size of single micron.
Ｌｉ含有酸化物の前駆物質であるＬｉ化合物と、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍの化合物と、が分散した溶液（Ｌｉ含有酸化物前駆体溶液）は、金属元素ＭがＡｌ、Ｔｉ、Ｚｒの場合は、これらの元素のアルコキシドをアルコール溶媒中でキレート剤：アセト酢酸エチル、アセチルアセトン、トリアタノールアミン等とキレート化することで安定化させ、急速な加水分解反応を抑制して造膜性を高めることが好ましい。キレート剤の配合比はｍｏｌ比でキレート剤／アルコキシド＝１～２が好ましい。ｍｏｌ比で１未満だと、キレート化していないアルコキシドが残存するため安定性が悪く、ｍｏｌ比で２超えだとキレート化しない不要なキレート剤が過剰に残存してしまう。キレート化したアルコキシド溶液は、さらに造膜性を高めるため水を添加して加水分解を適度に促進させるとより好ましい。水の添加量は、ｍｏｌ比で水／アルコキシド＝１～２が好ましい。ｍｏｌ比で１未満だと、加水分解の進行が不十分となり成膜時に有機分が残存しやすく、ｍｏｌ比で２超えだと加水分解が進行し過ぎて溶液中に沈殿が生じる場合がある。次いで、Ｌｉ化合物を溶媒に溶解し上記溶液に混合することで、Ｌｉ含有酸化物の前駆物質が分散した溶液を調製できる。また、金属元素ＭがＳｉの場合は、アルコキシドが安定なためキレート剤は不要で、水および酸触媒を加えて加水分解を促進させたあと、Ｌｉ化合物を溶媒に溶解し上記溶液に混合することで、Ｌｉ含有酸化物の前駆物質が分散した溶液を調製できる。
A solution (Li-containing oxide precursor solution) in which a Li compound that is a precursor of a Li-containing oxide and a compound of at least one metal element M selected from Si, Al, Ti, and Zr is dispersed is a metal element. When M is Al, Ti, or Zr, the alkoxide of these elements is stabilized by chelating with an chelating agent: ethyl acetoacetate, acetylacetone, tritananolamine, etc. in an alcohol solvent, and rapid hydrolysis reaction is performed. It is preferable to suppress and improve the film forming property. The mixing ratio of the chelating agent is preferably a chelating agent / alkoxide = 1 to 2 in terms of a molar ratio. If the molar ratio is less than 1, the unchelated alkoxide remains, resulting in poor stability. If the molar ratio exceeds 2, an unnecessary chelating agent that does not chelate remains excessively. It is more preferable that the chelated alkoxide solution further promotes hydrolysis by adding water in order to further improve the film forming property. The amount of water added is preferably water / alkoxide = 1 to 2 in molar ratio. If the molar ratio is less than 1, hydrolysis proceeds insufficiently and organic components tend to remain at the time of film formation. If the molar ratio exceeds 2, hydrolysis may proceed excessively and precipitation may occur in the solution. Next, the Li compound is dissolved in a solvent and mixed with the above solution to prepare a solution in which the precursor of the Li-containing oxide is dispersed. In addition, when the metal element M is Si, the alkoxide is stable, so a chelating agent is unnecessary. After adding water and an acid catalyst to promote hydrolysis, the Li compound is dissolved in a solvent and mixed with the above solution. Thus, a solution in which the precursor of the Li-containing oxide is dispersed can be prepared.
次いでＬｉ含有酸化物の前駆物質を含む上記溶液にＬｉと合金化可能なＳｉ粒子を加える。Ｓｉ粒子は乾燥粉または分散スラリーのどちらの形態でもよい。乾燥粉は、原料のＳｉを乾式粉砕、または湿式粉砕のあと溶媒を除去して得ることができる。分散スラリーは湿式粉砕することで得ることができる。Ｌｉ含有酸化物の前駆物質の分散溶液と、Ｓｉ粒子と、の混合スラリーは、溶媒を除去し、Ｓｉ粒子表面にＬｉ含有酸化物の前駆物質の被膜を形成させる。溶媒の除去は、スプレードライ、減圧乾燥などの方法を使用することができる。Ｌｉ含有酸化物の前駆物質の被膜は、硬化を促進させるため２００～１２００℃で熱処理することが好ましい。２００℃未満だと被膜の硬度およびＳｉ粒子との接着が弱く、１２００℃超えだと被膜とＳｉ粒子との反応が進行し放電容量が低下してしまう。熱処理時の雰囲気は非酸化性雰囲気が好ましく、Ａｒ等の非反応性ガスまたはＮ2等の低反応性ガスを主成分とし、Ｏ2等の酸化性ガスの濃度は１０００ｐｐｍ以下がより好ましい。
Next, Si particles that can be alloyed with Li are added to the solution containing the precursor of the Li-containing oxide. The Si particles may be in the form of a dry powder or a dispersed slurry. The dry powder can be obtained by dry pulverizing the raw material Si or removing the solvent after wet pulverization. The dispersion slurry can be obtained by wet pulverization. The mixed slurry of the Li-containing oxide precursor dispersion and the Si particles removes the solvent and forms a Li-containing oxide precursor film on the surface of the Si particles. For removal of the solvent, methods such as spray drying and drying under reduced pressure can be used. The Li-containing oxide precursor film is preferably heat-treated at 200 to 1200 ° C. in order to accelerate curing. When the temperature is lower than 200 ° C., the hardness of the coating and the adhesion with the Si particles are weak. When the temperature exceeds 1200 ° C., the reaction between the coating and the Si particles proceeds and the discharge capacity decreases. The atmosphere during the heat treatment is preferably a non-oxidizing atmosphere, and a non-reactive gas such as Ar or a low-reactive gas such as N 2 is the main component, and the concentration of the oxidizing gas such as O 2 is more preferably 1000 ppm or less.
次いで上記Ｌｉ含有酸化物を被覆したＳｉ粒子に、導電性結着物質を付着させて平均粒子径が０．５～１０μｍの集合粒子を作製する。上記の被覆Ｓｉ粒子をスプレードライで乾燥造粒した場合は、造粒体に導電性結着物質を含浸／被覆させ、乾燥後２００～１２００℃で熱処理することが好ましい。図２－（１）に上記の手順で得られる、表面にＬｉ含有酸化物３０の被膜を有し、該被膜の表面に導電性結着物質４０を有するＳｉ粒子２０が集合してなる集合粒子１０Ａの模式図を示す。上記の被覆Ｓｉ粒子を減圧乾燥／解砕して調製した場合は、導電性結着物質の前駆体が溶解した溶液に上記被覆Ｓｉ粒子の乾燥粉を加えてスラリーを調製し、スプレードライで乾燥造粒させたあと２００～１２００℃で熱処理することが好ましい。図２－（２）に上記の手順で得られる、表面にＬｉ含有酸化物３０の被膜を有し、該被膜の表面に導電性結着物質４０を有するＳｉ粒子２０が集合してなる集合粒子１０Ｂの模式図を示す。熱処理時の雰囲気は非酸化性雰囲気が好ましく、Ａｒ等の非反応性ガスまたはＮ2等の低反応性ガスを主成分とし、Ｏ2等の酸化性ガスの濃度は１０００ｐｐｍ以下がより好ましい。
Next, a conductive binder is adhered to the Si particles coated with the Li-containing oxide to produce aggregate particles having an average particle size of 0.5 to 10 μm. When the above coated Si particles are dried and granulated by spray drying, it is preferable to impregnate / coat the granulated body with a conductive binder and heat-treat at 200 to 1200 ° C. after drying. FIG. 2- (1) is an aggregated particle obtained by the above procedure, in which Si particles 20 having a coating of Li-containing oxide 30 on the surface and the conductive binder 40 on the surface of the coating are aggregated. A schematic diagram of 10A is shown. When the above coated Si particles are prepared by drying / disintegrating under reduced pressure, a slurry is prepared by adding dry powder of the above coated Si particles to a solution in which the precursor of the conductive binder is dissolved, and drying by spray drying. It is preferable to perform heat treatment at 200 to 1200 ° C. after granulation. FIG. 2 (2) shows an aggregated particle obtained by the above-described procedure, in which Si particles 20 having a coating of the Li-containing oxide 30 on the surface and the conductive binder 40 on the surface of the coating are aggregated. A schematic diagram of 10B is shown. The atmosphere during the heat treatment is preferably a non-oxidizing atmosphere, and a non-reactive gas such as Ar or a low-reactive gas such as N 2 is the main component, and the concentration of the oxidizing gas such as O 2 is more preferably 1000 ppm or less.
本発明のＬｉイオン二次電池用負極材料は、作製する電極の容量、密度、効率などの電池特性を調整するために、異種の黒鉛材料、ハードカーボンなどの炭素材料と混合して使用してもよい。
The negative electrode material for Li ion secondary batteries of the present invention is used by mixing with carbon materials such as different types of graphite materials and hard carbon in order to adjust battery characteristics such as capacity, density and efficiency of the electrodes to be produced. Also good.
〔負極〕
本発明のＬｉイオン二次電池用負極は、上記のＬｉイオン二次電池用負極材料を含有するリチウムイオン二次電池用負極である。
本発明のリチウムイオン二次電池用負極は、通常の負極の成形方法に準じて作製される。負極の作製は、本発明のＬｉイオン二次電池用負極材料に結合剤および溶媒を加えて調製した負極合剤を集電材に塗布することが好ましい。結合剤は、電解質に対して化学的、および電気化学的に安定性を示すものが好ましく、例えば、ポリテトラフルオロエチレン、ポリフッ化ビニリデンなどのフッ素系樹脂粉末、ポリエチレン、ポリビニルアルコールなどの樹脂粉末、カルボキシメチルセルロースなどが用いられる。これらを併用することもできる。結合剤は、通常、負極合剤の全量中の１～２０質量％の割合である。 [Negative electrode]
The negative electrode for Li ion secondary batteries of this invention is a negative electrode for lithium ion secondary batteries containing said negative electrode material for Li ion secondary batteries.
The negative electrode for a lithium ion secondary battery of the present invention is produced according to a normal method for forming a negative electrode. For the production of the negative electrode, it is preferable to apply to the current collector a negative electrode mixture prepared by adding a binder and a solvent to the negative electrode material for a Li ion secondary battery of the present invention. The binder preferably has chemical and electrochemical stability with respect to the electrolyte. For example, fluorine resin powders such as polytetrafluoroethylene and polyvinylidene fluoride, resin powders such as polyethylene and polyvinyl alcohol, Carboxymethylcellulose and the like are used. These can also be used together. The binder is usually 1 to 20% by mass in the total amount of the negative electrode mixture.
本発明のＬｉイオン二次電池用負極は、上記のＬｉイオン二次電池用負極材料を含有するリチウムイオン二次電池用負極である。
本発明のリチウムイオン二次電池用負極は、通常の負極の成形方法に準じて作製される。負極の作製は、本発明のＬｉイオン二次電池用負極材料に結合剤および溶媒を加えて調製した負極合剤を集電材に塗布することが好ましい。結合剤は、電解質に対して化学的、および電気化学的に安定性を示すものが好ましく、例えば、ポリテトラフルオロエチレン、ポリフッ化ビニリデンなどのフッ素系樹脂粉末、ポリエチレン、ポリビニルアルコールなどの樹脂粉末、カルボキシメチルセルロースなどが用いられる。これらを併用することもできる。結合剤は、通常、負極合剤の全量中の１～２０質量％の割合である。 [Negative electrode]
The negative electrode for Li ion secondary batteries of this invention is a negative electrode for lithium ion secondary batteries containing said negative electrode material for Li ion secondary batteries.
The negative electrode for a lithium ion secondary battery of the present invention is produced according to a normal method for forming a negative electrode. For the production of the negative electrode, it is preferable to apply to the current collector a negative electrode mixture prepared by adding a binder and a solvent to the negative electrode material for a Li ion secondary battery of the present invention. The binder preferably has chemical and electrochemical stability with respect to the electrolyte. For example, fluorine resin powders such as polytetrafluoroethylene and polyvinylidene fluoride, resin powders such as polyethylene and polyvinyl alcohol, Carboxymethylcellulose and the like are used. These can also be used together. The binder is usually 1 to 20% by mass in the total amount of the negative electrode mixture.
より具体的には、まず、本発明のＬｉイオン二次電池用負極材料を分級などにより所望の粒度に調整し、結合剤および溶媒と混合してスラリー状の負極合剤を調製する。すなわち、本発明のＬｉイオン二次電池用負極材料と、結合剤および水、イソピロピルアルコール、Ｎ－メチルピロリドン、ジメチルホルムアミドなどの溶媒を、公知の攪拌機、混合機、混練機、ニーダーなどを用いて攪拌混合してスラリーを調製する。該スラリーは、集電材の片面または両面に塗布し、乾燥することで、負極合剤層が均一かつ強固に接着した負極を得ることができる。負極合剤層の膜厚は１０～２００μｍ、好ましくは２０～１００μｍである。
More specifically, first, the negative electrode material for a Li ion secondary battery of the present invention is adjusted to a desired particle size by classification or the like, and mixed with a binder and a solvent to prepare a slurry negative electrode mixture. That is, the negative electrode material for the Li ion secondary battery of the present invention, a binder and a solvent such as water, isopropylpyrrolidone, N-methylpyrrolidone, dimethylformamide, and the like, using a known stirrer, mixer, kneader, kneader Use to stir and mix to prepare slurry. The slurry is applied to one or both sides of the current collector and dried to obtain a negative electrode in which the negative electrode mixture layer is uniformly and firmly bonded. The film thickness of the negative electrode mixture layer is 10 to 200 μm, preferably 20 to 100 μm.
負極の作製に用いる集電体の形状としては、特に限定されることはないが、箔状、メッシュ、エキスパンドメタルなどの網状などである。集電材の材質は、銅、ステンレス、ニッケルなどが好ましく、その集電体の厚みは通常５～２０μｍである。
なお、本発明のＬｉイオン二次電池用負極は、本発明の目的を損なわない範囲で、黒鉛質材料、ハードカーボンなどの炭素質材料、ＣＮＴなどの導電材を混合してもよい。 The shape of the current collector used for producing the negative electrode is not particularly limited, but may be a foil shape, a mesh shape, a net shape such as expanded metal, or the like. The material of the current collector is preferably copper, stainless steel, nickel or the like, and the thickness of the current collector is usually 5 to 20 μm.
In addition, the negative electrode for Li ion secondary batteries of this invention may mix carbonaceous materials, such as graphite material and hard carbon, and electrically conductive materials, such as CNT, in the range which does not impair the objective of this invention.
なお、本発明のＬｉイオン二次電池用負極は、本発明の目的を損なわない範囲で、黒鉛質材料、ハードカーボンなどの炭素質材料、ＣＮＴなどの導電材を混合してもよい。 The shape of the current collector used for producing the negative electrode is not particularly limited, but may be a foil shape, a mesh shape, a net shape such as expanded metal, or the like. The material of the current collector is preferably copper, stainless steel, nickel or the like, and the thickness of the current collector is usually 5 to 20 μm.
In addition, the negative electrode for Li ion secondary batteries of this invention may mix carbonaceous materials, such as graphite material and hard carbon, and electrically conductive materials, such as CNT, in the range which does not impair the objective of this invention.
〔リチウムイオン二次電池〕
本発明のＬｉイオン二次電池は、上述のＬｉイオン二次電池用負極、および正極、非水電解質を、例えば、負極、非水電解質、正極の順で積層し、電池の外装材内に収容することで構成される。非水電解質を溶媒に溶解する場合は、負極と正極の間にセパレータを配置する。本発明のＬｉイオン二次電池の構造、形状、形態は特に限定されず、用途に応じて円筒型、角型、コイン型、ボタン型、ラミネート型などの中から任意に選択することができる。より安全性の高い密閉型非水電解液電池を得るためには、過充電などの異常時に電池内圧上昇を感知して電流を遮断させる手段を備えたものを用いることが好ましい。 [Lithium ion secondary battery]
The Li ion secondary battery of the present invention includes the above-described negative electrode for a Li ion secondary battery, a positive electrode, and a nonaqueous electrolyte, for example, laminated in the order of the negative electrode, the nonaqueous electrolyte, and the positive electrode, and is accommodated in the battery outer packaging material. It is composed by doing. When the nonaqueous electrolyte is dissolved in a solvent, a separator is disposed between the negative electrode and the positive electrode. The structure, shape, and form of the Li-ion secondary battery of the present invention are not particularly limited, and can be arbitrarily selected from a cylindrical shape, a square shape, a coin shape, a button shape, a laminate shape, and the like depending on the application. In order to obtain a sealed nonaqueous electrolyte battery with higher safety, it is preferable to use a battery equipped with means for detecting an increase in the internal pressure of the battery and shutting off the current when an abnormality such as overcharging occurs.
本発明のＬｉイオン二次電池は、上述のＬｉイオン二次電池用負極、および正極、非水電解質を、例えば、負極、非水電解質、正極の順で積層し、電池の外装材内に収容することで構成される。非水電解質を溶媒に溶解する場合は、負極と正極の間にセパレータを配置する。本発明のＬｉイオン二次電池の構造、形状、形態は特に限定されず、用途に応じて円筒型、角型、コイン型、ボタン型、ラミネート型などの中から任意に選択することができる。より安全性の高い密閉型非水電解液電池を得るためには、過充電などの異常時に電池内圧上昇を感知して電流を遮断させる手段を備えたものを用いることが好ましい。 [Lithium ion secondary battery]
The Li ion secondary battery of the present invention includes the above-described negative electrode for a Li ion secondary battery, a positive electrode, and a nonaqueous electrolyte, for example, laminated in the order of the negative electrode, the nonaqueous electrolyte, and the positive electrode, and is accommodated in the battery outer packaging material. It is composed by doing. When the nonaqueous electrolyte is dissolved in a solvent, a separator is disposed between the negative electrode and the positive electrode. The structure, shape, and form of the Li-ion secondary battery of the present invention are not particularly limited, and can be arbitrarily selected from a cylindrical shape, a square shape, a coin shape, a button shape, a laminate shape, and the like depending on the application. In order to obtain a sealed nonaqueous electrolyte battery with higher safety, it is preferable to use a battery equipped with means for detecting an increase in the internal pressure of the battery and shutting off the current when an abnormality such as overcharging occurs.
＜正極＞
正極は、例えば正極材料と結合剤および溶媒からなる正極合剤を集電体の表面に塗布することにより形成される。正極活物質は、充分量のリチウムを吸蔵／離脱し得るリチウム含有遷移金属酸化物を選択するのが好ましい。リチウム含有遷移金属酸化物は、リチウムと遷移金属との複合酸化物であり、４種類以上の元素が含まれてもよい。複合酸化物は単独で使用しても、２種類以上を組合わせて使用してもよい。具体的には、ＬｉＣｏＯ2、ＬｉＮｉＯ2、ＬｉＭｎＯ2、ＬｉＮｉ0.9Ｃｏ0.1Ｏ2、ＬｉＮｉ0.5Ｃｏ0.5Ｏ2、ＬｉＦｅＰＯ4などがある。 <Positive electrode>
The positive electrode is formed, for example, by applying a positive electrode mixture composed of a positive electrode material, a binder, and a solvent to the surface of the current collector. As the positive electrode active material, it is preferable to select a lithium-containing transition metal oxide capable of inserting / extracting a sufficient amount of lithium. The lithium-containing transition metal oxide is a composite oxide of lithium and a transition metal, and may contain four or more elements. The composite oxide may be used alone or in combination of two or more. Specifically, there are LiCoO 2 , LiNiO 2 , LiMnO 2 , LiNi 0.9 Co 0.1 O 2 , LiNi 0.5 Co 0.5 O 2 , LiFePO 4 and the like.
正極は、例えば正極材料と結合剤および溶媒からなる正極合剤を集電体の表面に塗布することにより形成される。正極活物質は、充分量のリチウムを吸蔵／離脱し得るリチウム含有遷移金属酸化物を選択するのが好ましい。リチウム含有遷移金属酸化物は、リチウムと遷移金属との複合酸化物であり、４種類以上の元素が含まれてもよい。複合酸化物は単独で使用しても、２種類以上を組合わせて使用してもよい。具体的には、ＬｉＣｏＯ2、ＬｉＮｉＯ2、ＬｉＭｎＯ2、ＬｉＮｉ0.9Ｃｏ0.1Ｏ2、ＬｉＮｉ0.5Ｃｏ0.5Ｏ2、ＬｉＦｅＰＯ4などがある。 <Positive electrode>
The positive electrode is formed, for example, by applying a positive electrode mixture composed of a positive electrode material, a binder, and a solvent to the surface of the current collector. As the positive electrode active material, it is preferable to select a lithium-containing transition metal oxide capable of inserting / extracting a sufficient amount of lithium. The lithium-containing transition metal oxide is a composite oxide of lithium and a transition metal, and may contain four or more elements. The composite oxide may be used alone or in combination of two or more. Specifically, there are LiCoO 2 , LiNiO 2 , LiMnO 2 , LiNi 0.9 Co 0.1 O 2 , LiNi 0.5 Co 0.5 O 2 , LiFePO 4 and the like.
正極活物質は、前記化合物を単独で使用しても２種類以上併用してもよい。正極を形成するに際しては、従来公知の導電剤や結着剤などの各種添加剤を適宜に使用することができる。
集電体の形状は特に限定されないが、箔状またはメッシュ、エキスパンドメタル等の網状等のものが用いられる。集電体の材質は、アルミニウム、ステンレス、ニッケル等で、その厚さは通常１０～４０μｍである。 The positive electrode active material may be used alone or in combination of two or more. In forming the positive electrode, conventionally known various additives such as a conductive agent and a binder can be appropriately used.
The shape of the current collector is not particularly limited, but a foil shape or a mesh shape such as a mesh or expanded metal is used. The material of the current collector is aluminum, stainless steel, nickel or the like, and its thickness is usually 10 to 40 μm.
集電体の形状は特に限定されないが、箔状またはメッシュ、エキスパンドメタル等の網状等のものが用いられる。集電体の材質は、アルミニウム、ステンレス、ニッケル等で、その厚さは通常１０～４０μｍである。 The positive electrode active material may be used alone or in combination of two or more. In forming the positive electrode, conventionally known various additives such as a conductive agent and a binder can be appropriately used.
The shape of the current collector is not particularly limited, but a foil shape or a mesh shape such as a mesh or expanded metal is used. The material of the current collector is aluminum, stainless steel, nickel or the like, and its thickness is usually 10 to 40 μm.
＜非水電解質＞
本発明のＬｉイオン二次電池に用いられる非水電解質としては、通常の非水電解液に使用される電解質塩である、ＬｉＰＦ6、ＬｉＢＦ4、ＬｉＡｓＦ6、ＬｉＣｌＯ4、ＬｉＢ（Ｃ6Ｈ5）、ＬｉＣｌ、ＬｉＢｒ、ＬｉＣＦ3ＳＯ3、ＬｉＣＨ3ＳＯ3、ＬｉＮ（ＣＦ3ＳＯ2）2、ＬｉＣ（ＣＦ3ＳＯ2）3、ＬｉＮ（ＣＦ3ＣＨ2ＯＳＯ2）2、ＬｉＮ（ＣＦ3ＣＦ2ＯＳＯ2）2、ＬｉＮ（ＨＣＦ2ＣＦ2ＣＨ2ＯＳＯ2）2、ＬｉＮ（（ＣＦ3）2ＣＨＯＳＯ2）2、ＬｉＢ［｛Ｃ6Ｈ3（ＣＦ3）2｝］4、ＬｉＡｌＣｌ4、ＬｉＳｉＦ6などのリチウム塩を用いることができる。酸化安定性の点からは、特に、ＬｉＰＦ6、ＬｉＢＦ4が好ましい。電解液中の電解質塩濃度は０．１～５ｍｏｌ／Ｌが好ましく、０．５～３．０ｍｏｌ／Ｌがより好ましい。
非水電解質は液状の非水電解質としてもよく、固体電解質またはゲル電解質などの高分子電解質としてもよい。前者の場合、非水電解質電池は、いわゆるＬｉイオン二次電池として構成され、後者の場合は、非水電解質電池は高分子固体電解質、高分子ゲル電解質電池などの高分子電解質電池として構成される。 <Nonaqueous electrolyte>
The non-aqueous electrolyte used in Li-ion secondary battery of the present invention, an electrolyte salt used in the conventional non-aqueous electrolyte, LiPF 6, LiBF 4, LiAsF 6, LiClO 4, LiB (C 6 H 5 ), LiCl, LiBr, LiCF 3 SO 3 , LiCH 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiN (CF 3 CH 2 OSO 2 ) 2 , LiN (CF 3 CF 2 OSO 2) 2, LiN ( HCF 2CF 2 CH 2 OSO 2) 2, LiN ((CF 3) 2 CHOSO 2) 2, LiB [{C 6 H 3 (CF 3) 2}] 4, LiAlCl 4, Lithium salts such as LiSiF 6 can be used. From the viewpoint of oxidation stability, LiPF 6 and LiBF 4 are particularly preferable. The electrolyte salt concentration in the electrolytic solution is preferably from 0.1 to 5 mol / L, more preferably from 0.5 to 3.0 mol / L.
The non-aqueous electrolyte may be a liquid non-aqueous electrolyte or a polymer electrolyte such as a solid electrolyte or a gel electrolyte. In the former case, the non-aqueous electrolyte battery is configured as a so-called Li ion secondary battery, and in the latter case, the non-aqueous electrolyte battery is configured as a polymer electrolyte battery such as a polymer solid electrolyte or a polymer gel electrolyte battery. .
本発明のＬｉイオン二次電池に用いられる非水電解質としては、通常の非水電解液に使用される電解質塩である、ＬｉＰＦ6、ＬｉＢＦ4、ＬｉＡｓＦ6、ＬｉＣｌＯ4、ＬｉＢ（Ｃ6Ｈ5）、ＬｉＣｌ、ＬｉＢｒ、ＬｉＣＦ3ＳＯ3、ＬｉＣＨ3ＳＯ3、ＬｉＮ（ＣＦ3ＳＯ2）2、ＬｉＣ（ＣＦ3ＳＯ2）3、ＬｉＮ（ＣＦ3ＣＨ2ＯＳＯ2）2、ＬｉＮ（ＣＦ3ＣＦ2ＯＳＯ2）2、ＬｉＮ（ＨＣＦ2ＣＦ2ＣＨ2ＯＳＯ2）2、ＬｉＮ（（ＣＦ3）2ＣＨＯＳＯ2）2、ＬｉＢ［｛Ｃ6Ｈ3（ＣＦ3）2｝］4、ＬｉＡｌＣｌ4、ＬｉＳｉＦ6などのリチウム塩を用いることができる。酸化安定性の点からは、特に、ＬｉＰＦ6、ＬｉＢＦ4が好ましい。電解液中の電解質塩濃度は０．１～５ｍｏｌ／Ｌが好ましく、０．５～３．０ｍｏｌ／Ｌがより好ましい。
非水電解質は液状の非水電解質としてもよく、固体電解質またはゲル電解質などの高分子電解質としてもよい。前者の場合、非水電解質電池は、いわゆるＬｉイオン二次電池として構成され、後者の場合は、非水電解質電池は高分子固体電解質、高分子ゲル電解質電池などの高分子電解質電池として構成される。 <Nonaqueous electrolyte>
The non-aqueous electrolyte used in Li-ion secondary battery of the present invention, an electrolyte salt used in the conventional non-aqueous electrolyte, LiPF 6, LiBF 4, LiAsF 6, LiClO 4, LiB (C 6 H 5 ), LiCl, LiBr, LiCF 3 SO 3 , LiCH 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiN (CF 3 CH 2 OSO 2 ) 2 , LiN (CF 3 CF 2 OSO 2) 2, LiN ( HCF 2
The non-aqueous electrolyte may be a liquid non-aqueous electrolyte or a polymer electrolyte such as a solid electrolyte or a gel electrolyte. In the former case, the non-aqueous electrolyte battery is configured as a so-called Li ion secondary battery, and in the latter case, the non-aqueous electrolyte battery is configured as a polymer electrolyte battery such as a polymer solid electrolyte or a polymer gel electrolyte battery. .
非水電解質液を調製するための電解液としては、エチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネートなどのカーボネート、１，１－または１，２－ジメトキシエタン、１，２－ジエトキシエタン、テトラヒドロフラン、２－メチルテトラヒドロフラン、γ－ブチロラクトン、１，３－ジオキソラン、４－メチル－１，３－ジオキソラン、アニソール、ジエチルエーテルなどのエーテル、スルホラン、メチルスルホランなどのチオエーテル、アセトニトリル、クロロニトリル、プロピオニトリルなどのニトリル、ホウ酸トリメチル、ケイ酸テトラメチル、ニトロメタン、ジメチルホルムアミド、Ｎ－メチルピロリドン、酢酸エチル、トリメチルオルトホルメート、ニトロベンゼン、塩化ベンゾイル、臭化ベンゾイル、テトラヒドロチオフェン、ジメチルスルホキシド、３－メチル－２－オキサゾリドン、エチレングリコール、ジメチルサルファイトなどの非プロトン性有機溶媒などを用いることができる。さらに、充電時に電解液が還元分解して電池が劣化することを防ぐため、添加剤を加えても良い。公知の添加剤としては、フルオロエチレンカーボネート（ＦＥＣ）、ビニレンカーボネート（ＶＣ）、エチレンサルファイト（ＥＳ）などがあり、これらに限定されない。添加量は通常０．５～１０質量％程度である。
Examples of the electrolyte for preparing the non-aqueous electrolyte include carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate, 1,1- or 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran 2-methyltetrahydrofuran, γ-butyrolactone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, ethers such as anisole and diethyl ether, thioethers such as sulfolane and methylsulfolane, acetonitrile, chloronitrile, propionitrile Nitrile such as trimethyl borate, tetramethyl silicate, nitromethane, dimethylformamide, N-methylpyrrolidone, ethyl acetate, trimethyl orthoformate, nitrobenzene, benzoic chloride , It can be used benzoyl bromide, tetrahydrothiophene, dimethyl sulfoxide, 3-methyl-2-oxazolidone, ethylene glycol, aprotic organic solvents such as dimethyl sulfite and the like. Furthermore, an additive may be added to prevent the electrolytic solution from being reduced and decomposed during charging to deteriorate the battery. Known additives include, but are not limited to, fluoroethylene carbonate (FEC), vinylene carbonate (VC), ethylene sulfite (ES), and the like. The addition amount is usually about 0.5 to 10% by mass.
＜セパレータ＞
本発明のＬｉイオン二次電池においては、非水電解質を溶媒に溶解する場合は、負極と正極の間にセパレータを配置する。セパレータの材質は特に限定されるものではないが、例えば、織布、不織布、合成樹脂製微多孔膜などを用いることができる。前記セパレータの材質としては、合成樹脂製微多孔膜が好適であるが、なかでもポリオレフィン系微多孔膜が、厚さ、膜強度、膜抵抗の特性で好ましい。具体的には、ポリエチレンおよびポリプロピレン製微多孔膜、またはこれらを複合した微多孔膜等が好ましい。 <Separator>
In the Li ion secondary battery of the present invention, when the nonaqueous electrolyte is dissolved in a solvent, a separator is disposed between the negative electrode and the positive electrode. Although the material of a separator is not specifically limited, For example, a woven fabric, a nonwoven fabric, a synthetic resin microporous film, etc. can be used. As a material for the separator, a microporous membrane made of synthetic resin is suitable. Among them, a polyolefin microporous membrane is preferable in terms of thickness, membrane strength, and membrane resistance. Specifically, polyethylene and polypropylene microporous membranes, or microporous membranes combining these are preferred.
本発明のＬｉイオン二次電池においては、非水電解質を溶媒に溶解する場合は、負極と正極の間にセパレータを配置する。セパレータの材質は特に限定されるものではないが、例えば、織布、不織布、合成樹脂製微多孔膜などを用いることができる。前記セパレータの材質としては、合成樹脂製微多孔膜が好適であるが、なかでもポリオレフィン系微多孔膜が、厚さ、膜強度、膜抵抗の特性で好ましい。具体的には、ポリエチレンおよびポリプロピレン製微多孔膜、またはこれらを複合した微多孔膜等が好ましい。 <Separator>
In the Li ion secondary battery of the present invention, when the nonaqueous electrolyte is dissolved in a solvent, a separator is disposed between the negative electrode and the positive electrode. Although the material of a separator is not specifically limited, For example, a woven fabric, a nonwoven fabric, a synthetic resin microporous film, etc. can be used. As a material for the separator, a microporous membrane made of synthetic resin is suitable. Among them, a polyolefin microporous membrane is preferable in terms of thickness, membrane strength, and membrane resistance. Specifically, polyethylene and polypropylene microporous membranes, or microporous membranes combining these are preferred.
次に本発明を実施例により具体的に説明するが、本発明はこれら実施例に限定されるものではない。また以下の実施例および比較例では、図２に示すように、少なくとも表面の一部に本発明の負極材料を有する負極合剤２が付着した集電体（負極）７ｂとリチウム箔よりなる対極（正極）４から構成される単極評価用のボタン型二次電池を作製して評価した。実電池は、本発明の概念に基づき、公知の方法に準じて作製することができる。
Next, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In the following examples and comparative examples, as shown in FIG. 2, a current collector (negative electrode) 7b having a negative electrode mixture 2 having the negative electrode material of the present invention attached to at least a part of its surface and a counter electrode comprising a lithium foil A button type secondary battery for single electrode evaluation composed of (positive electrode) 4 was prepared and evaluated. An actual battery can be produced according to a known method based on the concept of the present invention.
実施例で用いた測定法は以下である。
〔測定法〕
（１）平均粒径の測定
平均粒子径は、レーザー回折式粒度計で測定される累積度数が体積百分率で５０％となる粒子径とした。 The measurement methods used in the examples are as follows.
[Measurement method]
(1) Measurement of average particle diameter The average particle diameter was a particle diameter at which the cumulative frequency measured with a laser diffraction particle size meter was 50% by volume.
〔測定法〕
（１）平均粒径の測定
平均粒子径は、レーザー回折式粒度計で測定される累積度数が体積百分率で５０％となる粒子径とした。 The measurement methods used in the examples are as follows.
[Measurement method]
(1) Measurement of average particle diameter The average particle diameter was a particle diameter at which the cumulative frequency measured with a laser diffraction particle size meter was 50% by volume.
（２）Ｌｉ含有酸化物のＬｉと、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍの含有割合
金属元素Ｍの含有量は添加量で規定した。定量測定を行う場合はＩＣＰ発光分析、原子吸光分析などで行うことができる。 (2) Content ratio of Li of Li-containing oxide and at least one metal element M selected from Si, Al, Ti, and Zr The content of the metal element M was defined by the addition amount. When quantitative measurement is performed, ICP emission analysis, atomic absorption analysis, or the like can be used.
金属元素Ｍの含有量は添加量で規定した。定量測定を行う場合はＩＣＰ発光分析、原子吸光分析などで行うことができる。 (2) Content ratio of Li of Li-containing oxide and at least one metal element M selected from Si, Al, Ti, and Zr The content of the metal element M was defined by the addition amount. When quantitative measurement is performed, ICP emission analysis, atomic absorption analysis, or the like can be used.
（３）電池特性
下記の構成で作製された評価電池について、２５℃の温度下で以下に示す充放電試験を行い、初期充放電特性、急速充電率、急速放電率およびサイクル特性を計算した。 (3) Battery characteristics About the evaluation battery produced with the following structure, the charge / discharge test shown below was performed at the temperature of 25 degreeC, and the initial stage charge / discharge characteristic, the rapid charge rate, the rapid discharge rate, and the cycle characteristic were calculated.
下記の構成で作製された評価電池について、２５℃の温度下で以下に示す充放電試験を行い、初期充放電特性、急速充電率、急速放電率およびサイクル特性を計算した。 (3) Battery characteristics About the evaluation battery produced with the following structure, the charge / discharge test shown below was performed at the temperature of 25 degreeC, and the initial stage charge / discharge characteristic, the rapid charge rate, the rapid discharge rate, and the cycle characteristic were calculated.
＜初期充放電特性＞
回路電圧が０ｍＶに達するまで０．２Ｃ（０．９ｍＡ）の定電流充電を行った後、回路電圧が０ｍＶに達した時点で定電圧充電に切替え、さらに電流値が２０μＡになるまで充電を続けた。その間の通電量から質量当たりの充電容量（単位：ｍＡｈ／ｇ）を求めた。その後、１２０分間保持した。次に０．２Ｃの電流値で回路電圧が１．５Ｖに達するまで定電流放電を行い、この間の通電量から質量当たりの放電容量（単位：ｍＡｈ／ｇ）を求めた。初期充放電効率は下記式（１）により計算した。
この試験では、リチウムイオンを負極材料に吸蔵する過程を充電、負極材料から離脱する過程を放電とし、結果を表１に示した。
なお充放電レートの１Ｃとは、電池容量に対する充放電時の電流の相対的な比率の指標で、公称容量値の容量を持つセルを定電流充放電してちょうど１時間で充放電が終了となる電流値のことである。
式（１） … 初期充放電効率（％）＝（放電容量／充電容量）×１００ <Initial charge / discharge characteristics>
After constant current charging of 0.2C (0.9mA) until the circuit voltage reaches 0mV, switching to constant voltage charging when the circuit voltage reaches 0mV and further charging until the current value reaches 20μA It was. The charging capacity per unit mass (unit: mAh / g) was determined from the amount of electricity applied during that time. Thereafter, it was held for 120 minutes. Next, constant current discharge was performed until the circuit voltage reached 1.5 V at a current value of 0.2 C, and the discharge capacity per unit mass (unit: mAh / g) was determined from the amount of current supplied during this period. The initial charge / discharge efficiency was calculated by the following formula (1).
In this test, the process of occluding lithium ions in the negative electrode material was charged, and the process of detaching from the negative electrode material was discharge, and the results are shown in Table 1.
The charge / discharge rate of 1C is an indicator of the relative ratio of the current during charging / discharging to the battery capacity, and charging / discharging is completed in just one hour after constant-current charging / discharging of a cell having a nominal capacity value. Current value.
Formula (1): Initial charge / discharge efficiency (%) = (discharge capacity / charge capacity) × 100
回路電圧が０ｍＶに達するまで０．２Ｃ（０．９ｍＡ）の定電流充電を行った後、回路電圧が０ｍＶに達した時点で定電圧充電に切替え、さらに電流値が２０μＡになるまで充電を続けた。その間の通電量から質量当たりの充電容量（単位：ｍＡｈ／ｇ）を求めた。その後、１２０分間保持した。次に０．２Ｃの電流値で回路電圧が１．５Ｖに達するまで定電流放電を行い、この間の通電量から質量当たりの放電容量（単位：ｍＡｈ／ｇ）を求めた。初期充放電効率は下記式（１）により計算した。
この試験では、リチウムイオンを負極材料に吸蔵する過程を充電、負極材料から離脱する過程を放電とし、結果を表１に示した。
なお充放電レートの１Ｃとは、電池容量に対する充放電時の電流の相対的な比率の指標で、公称容量値の容量を持つセルを定電流充放電してちょうど１時間で充放電が終了となる電流値のことである。
式（１） … 初期充放電効率（％）＝（放電容量／充電容量）×１００ <Initial charge / discharge characteristics>
After constant current charging of 0.2C (0.9mA) until the circuit voltage reaches 0mV, switching to constant voltage charging when the circuit voltage reaches 0mV and further charging until the current value reaches 20μA It was. The charging capacity per unit mass (unit: mAh / g) was determined from the amount of electricity applied during that time. Thereafter, it was held for 120 minutes. Next, constant current discharge was performed until the circuit voltage reached 1.5 V at a current value of 0.2 C, and the discharge capacity per unit mass (unit: mAh / g) was determined from the amount of current supplied during this period. The initial charge / discharge efficiency was calculated by the following formula (1).
In this test, the process of occluding lithium ions in the negative electrode material was charged, and the process of detaching from the negative electrode material was discharge, and the results are shown in Table 1.
The charge / discharge rate of 1C is an indicator of the relative ratio of the current during charging / discharging to the battery capacity, and charging / discharging is completed in just one hour after constant-current charging / discharging of a cell having a nominal capacity value. Current value.
Formula (1): Initial charge / discharge efficiency (%) = (discharge capacity / charge capacity) × 100
＜サイクル特性＞
質量当たりの放電容量、初期充放電効率を評価した評価電池とは別の評価用電池を作製し、以下のような評価を行なった。
回路電圧が０ｍＶに達するまで１Ｃの定電流充電を行った後、定電圧充電に切替え、電流値が２０μＡになるまで充電を続けた後、１２０分間休止した。次に１Ｃの電流値で、回路電圧が１.５Ｖに達するまで定電流放電を行う操作を３０回繰返した。サイクル特性は、得られた質量当たりの放電容量から下記式（２）を用いて容量維持率を計算して評価した。各回効率は、各サイクルにおける充電容量と放電容量から下記式（３）を用いて計算して評価した。なお、各回効率は活物質の充電量と電解液の還元分解に使われた電荷消費量の総和が分母となることから、値が大きいほど電解液が分解しにくいことを示す。
式（２） … 容量維持率（％）＝（３０サイクルにおける放電容量／第１サイクルにおける放電容量）×１００
式（３） … 各回効率（％）＝（３０サイクルにおける放電容量／３０サイクルにおける充電容量）×１００ <Cycle characteristics>
A battery for evaluation different from the evaluation battery that evaluated the discharge capacity per mass and the initial charge / discharge efficiency was produced, and the following evaluation was performed.
After constant current charging at 1 C until the circuit voltage reached 0 mV, switching to constant voltage charging was continued until the current value reached 20 μA, and then rested for 120 minutes. Next, the operation of performing a constant current discharge at a current value of 1 C until the circuit voltage reached 1.5 V was repeated 30 times. The cycle characteristics were evaluated by calculating the capacity maintenance rate using the following formula (2) from the obtained discharge capacity per mass. Each efficiency was evaluated by calculating from the charge capacity and discharge capacity in each cycle using the following formula (3). In addition, since each time efficiency becomes the denominator of the charge amount of the active material and the charge consumption amount used for the reductive decomposition of the electrolytic solution, the larger the value, the more difficult the electrolytic solution is decomposed.
Formula (2): Capacity maintenance ratio (%) = (discharge capacity in 30 cycles / discharge capacity in the first cycle) × 100
Formula (3): Each time efficiency (%) = (discharge capacity in 30 cycles / charge capacity in 30 cycles) × 100
質量当たりの放電容量、初期充放電効率を評価した評価電池とは別の評価用電池を作製し、以下のような評価を行なった。
回路電圧が０ｍＶに達するまで１Ｃの定電流充電を行った後、定電圧充電に切替え、電流値が２０μＡになるまで充電を続けた後、１２０分間休止した。次に１Ｃの電流値で、回路電圧が１.５Ｖに達するまで定電流放電を行う操作を３０回繰返した。サイクル特性は、得られた質量当たりの放電容量から下記式（２）を用いて容量維持率を計算して評価した。各回効率は、各サイクルにおける充電容量と放電容量から下記式（３）を用いて計算して評価した。なお、各回効率は活物質の充電量と電解液の還元分解に使われた電荷消費量の総和が分母となることから、値が大きいほど電解液が分解しにくいことを示す。
式（２） … 容量維持率（％）＝（３０サイクルにおける放電容量／第１サイクルにおける放電容量）×１００
式（３） … 各回効率（％）＝（３０サイクルにおける放電容量／３０サイクルにおける充電容量）×１００ <Cycle characteristics>
A battery for evaluation different from the evaluation battery that evaluated the discharge capacity per mass and the initial charge / discharge efficiency was produced, and the following evaluation was performed.
After constant current charging at 1 C until the circuit voltage reached 0 mV, switching to constant voltage charging was continued until the current value reached 20 μA, and then rested for 120 minutes. Next, the operation of performing a constant current discharge at a current value of 1 C until the circuit voltage reached 1.5 V was repeated 30 times. The cycle characteristics were evaluated by calculating the capacity maintenance rate using the following formula (2) from the obtained discharge capacity per mass. Each efficiency was evaluated by calculating from the charge capacity and discharge capacity in each cycle using the following formula (3). In addition, since each time efficiency becomes the denominator of the charge amount of the active material and the charge consumption amount used for the reductive decomposition of the electrolytic solution, the larger the value, the more difficult the electrolytic solution is decomposed.
Formula (2): Capacity maintenance ratio (%) = (discharge capacity in 30 cycles / discharge capacity in the first cycle) × 100
Formula (3): Each time efficiency (%) = (discharge capacity in 30 cycles / charge capacity in 30 cycles) × 100
〔負極材料の作製〕
（実施例１）
Ａｌ－ｓｅｃブトキシド０．０２ｍｏｌと、アセト酢酸エチル０．０２ｍｏｌと、をイソプロパノール溶媒に溶解して第一溶液を作製し、次いで酢酸Ｌｉ二水塩０．００２ｍｏｌを溶解したエタノール溶液を第一溶液に加えて第二溶液を作製した。次いで平均粒子径０．１５μｍのＳｉ粒子２９ｇを第二溶液に加え、溶媒を除去したあと、窒素の非酸化性雰囲気下１０００℃で焼成して、Ｌｉ、および金属元素ＭとしてＡｌを含有するＬｉ含有酸化物の被膜を有するＳｉ粒子を得た。次いで導電性結着物質の前駆体であるレゾール型フェノール樹脂溶液（不揮発分７１質量％）が溶解した水溶液に、上述の被覆Ｓｉ粒子を加えてスラリーを作製した。このときフェノール樹脂溶液／被覆Ｓｉ粒子＝１／２質量比とした。上記スラリーはスプレードライ装置で噴霧乾燥処理し、次いで窒素の非酸化性雰囲気下において１０００℃で焼成することにより球状の乾燥造粒体を得た。 [Production of negative electrode material]
Example 1
A first solution is prepared by dissolving 0.02 mol of Al-sec butoxide and 0.02 mol of ethyl acetoacetate in an isopropanol solvent, and then an ethanol solution in which 0.002 mol of acetic acid Li dihydrate is dissolved is used as the first solution. In addition, a second solution was prepared. Next, 29 g of Si particles having an average particle size of 0.15 μm was added to the second solution, and after removing the solvent, the mixture was baked at 1000 ° C. in a non-oxidizing atmosphere of nitrogen, and Li containing Li as a metal element M and Li containing Al Si particles having an oxide coating film were obtained. Next, the above-mentioned coated Si particles were added to an aqueous solution in which a resol-type phenol resin solution (nonvolatile content: 71% by mass), which is a precursor of the conductive binder, was dissolved to prepare a slurry. At this time, the phenol resin solution / coated Si particles = 1/2 mass ratio. The slurry was spray-dried with a spray-drying apparatus, and then fired at 1000 ° C. in a non-oxidizing atmosphere of nitrogen to obtain a spherical dry granulated body.
（実施例１）
Ａｌ－ｓｅｃブトキシド０．０２ｍｏｌと、アセト酢酸エチル０．０２ｍｏｌと、をイソプロパノール溶媒に溶解して第一溶液を作製し、次いで酢酸Ｌｉ二水塩０．００２ｍｏｌを溶解したエタノール溶液を第一溶液に加えて第二溶液を作製した。次いで平均粒子径０．１５μｍのＳｉ粒子２９ｇを第二溶液に加え、溶媒を除去したあと、窒素の非酸化性雰囲気下１０００℃で焼成して、Ｌｉ、および金属元素ＭとしてＡｌを含有するＬｉ含有酸化物の被膜を有するＳｉ粒子を得た。次いで導電性結着物質の前駆体であるレゾール型フェノール樹脂溶液（不揮発分７１質量％）が溶解した水溶液に、上述の被覆Ｓｉ粒子を加えてスラリーを作製した。このときフェノール樹脂溶液／被覆Ｓｉ粒子＝１／２質量比とした。上記スラリーはスプレードライ装置で噴霧乾燥処理し、次いで窒素の非酸化性雰囲気下において１０００℃で焼成することにより球状の乾燥造粒体を得た。 [Production of negative electrode material]
Example 1
A first solution is prepared by dissolving 0.02 mol of Al-sec butoxide and 0.02 mol of ethyl acetoacetate in an isopropanol solvent, and then an ethanol solution in which 0.002 mol of acetic acid Li dihydrate is dissolved is used as the first solution. In addition, a second solution was prepared. Next, 29 g of Si particles having an average particle size of 0.15 μm was added to the second solution, and after removing the solvent, the mixture was baked at 1000 ° C. in a non-oxidizing atmosphere of nitrogen, and Li containing Li as a metal element M and Li containing Al Si particles having an oxide coating film were obtained. Next, the above-mentioned coated Si particles were added to an aqueous solution in which a resol-type phenol resin solution (nonvolatile content: 71% by mass), which is a precursor of the conductive binder, was dissolved to prepare a slurry. At this time, the phenol resin solution / coated Si particles = 1/2 mass ratio. The slurry was spray-dried with a spray-drying apparatus, and then fired at 1000 ° C. in a non-oxidizing atmosphere of nitrogen to obtain a spherical dry granulated body.
（実施例２）
実施例１のＡｌ－ｓｅｃブトキシドの代わりにＴｉ－ｉｓｏプロポキシドを用いた以外は実施例１と同様にして球状の乾燥造粒体を得た。 (Example 2)
Spherical dry granules were obtained in the same manner as in Example 1 except that Ti-isopropoxide was used instead of Al-sec butoxide in Example 1.
実施例１のＡｌ－ｓｅｃブトキシドの代わりにＴｉ－ｉｓｏプロポキシドを用いた以外は実施例１と同様にして球状の乾燥造粒体を得た。 (Example 2)
Spherical dry granules were obtained in the same manner as in Example 1 except that Ti-isopropoxide was used instead of Al-sec butoxide in Example 1.
（実施例３）
実施例１のＡｌ－ｓｅｃブトキシドの代わりにＺｒ－プロポキシドを用いた以外は実施例１と同様にして球状の乾燥造粒体を得た。 (Example 3)
Spherical dry granules were obtained in the same manner as in Example 1 except that Zr-propoxide was used instead of Al-sec butoxide in Example 1.
実施例１のＡｌ－ｓｅｃブトキシドの代わりにＺｒ－プロポキシドを用いた以外は実施例１と同様にして球状の乾燥造粒体を得た。 (Example 3)
Spherical dry granules were obtained in the same manner as in Example 1 except that Zr-propoxide was used instead of Al-sec butoxide in Example 1.
（実施例４）
Ｓｉ－メトキシド０．０２ｍｏｌとイソプロパノール溶媒に溶解して第一溶液を作製し、次いで酢酸Ｌｉ二水塩０．００２ｍｏｌを溶解したエタノール溶液を第一溶液に加えて２時間還流して第二溶液を作製した以外は、実施例１と同様にして球状の乾燥造粒体を得た。 Example 4
A first solution is prepared by dissolving in 0.02 mol of Si-methoxide and an isopropanol solvent, and then an ethanol solution in which 0.002 mol of Lithium acetate dihydrate is dissolved is added to the first solution and refluxed for 2 hours. A spherical dry granulated body was obtained in the same manner as in Example 1 except that it was produced.
Ｓｉ－メトキシド０．０２ｍｏｌとイソプロパノール溶媒に溶解して第一溶液を作製し、次いで酢酸Ｌｉ二水塩０．００２ｍｏｌを溶解したエタノール溶液を第一溶液に加えて２時間還流して第二溶液を作製した以外は、実施例１と同様にして球状の乾燥造粒体を得た。 Example 4
A first solution is prepared by dissolving in 0.02 mol of Si-methoxide and an isopropanol solvent, and then an ethanol solution in which 0.002 mol of Lithium acetate dihydrate is dissolved is added to the first solution and refluxed for 2 hours. A spherical dry granulated body was obtained in the same manner as in Example 1 except that it was produced.
（実施例５）
実施例１の導電性結着物質の前駆体としてカーボンブラックを分散させたポリアミド酸溶液を用い、スプレードライ装置で噴霧乾燥処理したあとの熱処理を３００℃にした以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Example 5)
As in Example 1, except that a polyamic acid solution in which carbon black was dispersed was used as a precursor of the conductive binder of Example 1 and the heat treatment after spray drying was performed at 300 ° C. using a spray dryer. Thus, a spherical dry granulated body was obtained.
実施例１の導電性結着物質の前駆体としてカーボンブラックを分散させたポリアミド酸溶液を用い、スプレードライ装置で噴霧乾燥処理したあとの熱処理を３００℃にした以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Example 5)
As in Example 1, except that a polyamic acid solution in which carbon black was dispersed was used as a precursor of the conductive binder of Example 1 and the heat treatment after spray drying was performed at 300 ° C. using a spray dryer. Thus, a spherical dry granulated body was obtained.
（実施例６）
Ｌｉ含有酸化物の被覆量を７．０％となるように調整した以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Example 6)
A spherical dry granule was obtained in the same manner as in Example 1 except that the coating amount of the Li-containing oxide was adjusted to 7.0%.
Ｌｉ含有酸化物の被覆量を７．０％となるように調整した以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Example 6)
A spherical dry granule was obtained in the same manner as in Example 1 except that the coating amount of the Li-containing oxide was adjusted to 7.0%.
（実施例７）
実施例1においてスプレードライ装置の噴霧条件を調整して、得られた球状の乾燥造粒体の平均粒径を９．５μｍとした以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Example 7)
Spherical dry granulated material as in Example 1 except that the spraying conditions of the spray drying apparatus in Example 1 were adjusted so that the average spherical particle size of the obtained spherical dry granulated material was 9.5 μm. Got.
実施例1においてスプレードライ装置の噴霧条件を調整して、得られた球状の乾燥造粒体の平均粒径を９．５μｍとした以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Example 7)
Spherical dry granulated material as in Example 1 except that the spraying conditions of the spray drying apparatus in Example 1 were adjusted so that the average spherical particle size of the obtained spherical dry granulated material was 9.5 μm. Got.
（比較例１）
被覆しない平均粒子径０．１５μｍのＳｉ粒子を用いたこと以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Comparative Example 1)
A spherical dry granulated body was obtained in the same manner as in Example 1 except that Si particles having an average particle diameter of 0.15 μm that were not coated were used.
被覆しない平均粒子径０．１５μｍのＳｉ粒子を用いたこと以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Comparative Example 1)
A spherical dry granulated body was obtained in the same manner as in Example 1 except that Si particles having an average particle diameter of 0.15 μm that were not coated were used.
（比較例２）
スプレードライ装置で噴霧乾燥処理した造粒体の平均粒子径を１５μｍに調整したこと以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Comparative Example 2)
A spherical dried granulated body was obtained in the same manner as in Example 1 except that the average particle size of the granulated body spray-dried with a spray drying apparatus was adjusted to 15 μm.
スプレードライ装置で噴霧乾燥処理した造粒体の平均粒子径を１５μｍに調整したこと以外は、実施例１と同様にして球状の乾燥造粒体を得た。 (Comparative Example 2)
A spherical dried granulated body was obtained in the same manner as in Example 1 except that the average particle size of the granulated body spray-dried with a spray drying apparatus was adjusted to 15 μm.
（比較例３）
結着物質にカーボンブラックを含まないポリイミド樹脂を用いたこと以外は、実施例５と同様にして球状の乾燥造粒体を得た。 (Comparative Example 3)
A spherical dry granule was obtained in the same manner as in Example 5 except that a polyimide resin containing no carbon black was used as the binder.
結着物質にカーボンブラックを含まないポリイミド樹脂を用いたこと以外は、実施例５と同様にして球状の乾燥造粒体を得た。 (Comparative Example 3)
A spherical dry granule was obtained in the same manner as in Example 5 except that a polyimide resin containing no carbon black was used as the binder.
〔作用電極（負極）の作製〕
上記Ｌｉ含有酸化物被膜／導電性結着物質を有するＳｉ粒子、または比較例のＳｉ複合粒子を６質量部と、球状天然黒鉛粒子９４質量部の負極材、および結合剤としてのカルボキシメチルセルロース１．５質量部、スチレン－ブタジエンゴム１．５質量部を水に入れ、攪拌して負極合剤ペーストを調製した。前記負極合剤ペーストを厚さ１５μｍの銅箔上に均一な厚さで塗布し、さらに真空中１００℃で分散媒の水を蒸発させて乾燥した。次いで、この銅箔上に塗布された負極合剤層をハンドプレスによって加圧した。さらに、銅箔と負極合剤層を直径１５．５ｍｍの円柱状に打抜いてプレスし、銅箔に密着した負極合剤層を有する作用電極（負極）を作製した。負極合剤層の密度は１.６５ｇ／ｃｍ3であった。 [Production of working electrode (negative electrode)]
6 parts by mass of Si particles having the above Li-containing oxide film / conductive binder or Si composite particles of Comparative Example, 94 parts by mass of spherical natural graphite particles, and carboxymethyl cellulose as a binder. 5 parts by mass and 1.5 parts by mass of styrene-butadiene rubber were placed in water and stirred to prepare a negative electrode mixture paste. The negative electrode mixture paste was applied on a copper foil having a thickness of 15 μm to a uniform thickness, and further, water in a dispersion medium was evaporated at 100 ° C. in a vacuum to dry the paste. Next, the negative electrode mixture layer applied on the copper foil was pressed by a hand press. Furthermore, the copper foil and the negative electrode mixture layer were punched into a cylindrical shape having a diameter of 15.5 mm and pressed to produce a working electrode (negative electrode) having a negative electrode mixture layer adhered to the copper foil. The density of the negative electrode mixture layer was 1.65 g / cm 3 .
上記Ｌｉ含有酸化物被膜／導電性結着物質を有するＳｉ粒子、または比較例のＳｉ複合粒子を６質量部と、球状天然黒鉛粒子９４質量部の負極材、および結合剤としてのカルボキシメチルセルロース１．５質量部、スチレン－ブタジエンゴム１．５質量部を水に入れ、攪拌して負極合剤ペーストを調製した。前記負極合剤ペーストを厚さ１５μｍの銅箔上に均一な厚さで塗布し、さらに真空中１００℃で分散媒の水を蒸発させて乾燥した。次いで、この銅箔上に塗布された負極合剤層をハンドプレスによって加圧した。さらに、銅箔と負極合剤層を直径１５．５ｍｍの円柱状に打抜いてプレスし、銅箔に密着した負極合剤層を有する作用電極（負極）を作製した。負極合剤層の密度は１.６５ｇ／ｃｍ3であった。 [Production of working electrode (negative electrode)]
6 parts by mass of Si particles having the above Li-containing oxide film / conductive binder or Si composite particles of Comparative Example, 94 parts by mass of spherical natural graphite particles, and carboxymethyl cellulose as a binder. 5 parts by mass and 1.5 parts by mass of styrene-butadiene rubber were placed in water and stirred to prepare a negative electrode mixture paste. The negative electrode mixture paste was applied on a copper foil having a thickness of 15 μm to a uniform thickness, and further, water in a dispersion medium was evaporated at 100 ° C. in a vacuum to dry the paste. Next, the negative electrode mixture layer applied on the copper foil was pressed by a hand press. Furthermore, the copper foil and the negative electrode mixture layer were punched into a cylindrical shape having a diameter of 15.5 mm and pressed to produce a working electrode (negative electrode) having a negative electrode mixture layer adhered to the copper foil. The density of the negative electrode mixture layer was 1.65 g / cm 3 .
電解液は、エチレンカーボネート（ＥＣ）３３体積％とメチルエチルカーボネート（ＭＥＣ）６７体積％の混合溶剤に、ＬｉＰＦ6を１ｍｏｌ／Ｌとなる濃度で溶解させ、非水電解液を調製した。また調製した非水電解液は厚さ２０μｍのポリプロピレン多孔質体のセパレータに含浸させ、電解液が含浸したセパレータを作製した。なお、実電池については、本発明の概念に基づき、公知の方法に準じて作製することができる。
The electrolyte was prepared by dissolving LiPF 6 at a concentration of 1 mol / L in a mixed solvent of 33% by volume of ethylene carbonate (EC) and 67% by volume of methyl ethyl carbonate (MEC) to prepare a non-aqueous electrolyte. The prepared non-aqueous electrolyte was impregnated into a 20 μm thick polypropylene porous separator to produce a separator impregnated with the electrolyte. In addition, about a real battery, it can produce according to a well-known method based on the concept of this invention.
〔評価電池の作製〕
図２に評価電池の構成としてボタン型二次電池を示す。
外装カップ１と外装缶３は、その周縁部において絶縁ガスケット６を介在させ、両周縁部をかしめて密閉した。その内部に外装缶３の内面から順に、ニッケルネットからなる集電体７ａ、リチウム箔よりなる円筒状の対極（正極）４、電解液が含浸されたセパレータ５、負極合剤２が付着した銅箔からなる集電体７ｂが積層された電池である。
前記評価電池は電解液を含浸させたセパレータ５を集電体７ｂと負極合剤２からなる作用電極（負極）と、集電体７ａに密着した対極４との間に挟んで積層した後、集電体７ｂを外装カップ１内に、対極４を外装缶３内に収容して、外装カップ１と外装缶３とを合わせ、さらに、外装カップ１と外装缶３との周縁部に絶縁ガスケット６を介在させ、両周縁部をかしめて密閉して作製した。 [Production of evaluation battery]
FIG. 2 shows a button type secondary battery as a configuration of the evaluation battery.
Theexterior cup 1 and the exterior can 3 were sealed by interposing an insulating gasket 6 at the peripheral portion thereof and caulking both peripheral portions. A copper current collector 7 a made of nickel net, a cylindrical counter electrode (positive electrode) 4 made of lithium foil, a separator 5 impregnated with an electrolytic solution, and a negative electrode mixture 2 are attached to the inside of the outer can 3 in that order. A battery in which a current collector 7b made of foil is laminated.
In the evaluation battery, theseparator 5 impregnated with the electrolytic solution was sandwiched between the current collector 7b and the working electrode (negative electrode) made of the negative electrode mixture 2, and the counter electrode 4 in close contact with the current collector 7a. The current collector 7b is accommodated in the exterior cup 1, the counter electrode 4 is accommodated in the exterior can 3, the exterior cup 1 and the exterior can 3 are combined, and an insulating gasket is provided at the peripheral edge between the exterior cup 1 and the exterior can 3. 6 was interposed, and both peripheral portions were caulked and sealed.
図２に評価電池の構成としてボタン型二次電池を示す。
外装カップ１と外装缶３は、その周縁部において絶縁ガスケット６を介在させ、両周縁部をかしめて密閉した。その内部に外装缶３の内面から順に、ニッケルネットからなる集電体７ａ、リチウム箔よりなる円筒状の対極（正極）４、電解液が含浸されたセパレータ５、負極合剤２が付着した銅箔からなる集電体７ｂが積層された電池である。
前記評価電池は電解液を含浸させたセパレータ５を集電体７ｂと負極合剤２からなる作用電極（負極）と、集電体７ａに密着した対極４との間に挟んで積層した後、集電体７ｂを外装カップ１内に、対極４を外装缶３内に収容して、外装カップ１と外装缶３とを合わせ、さらに、外装カップ１と外装缶３との周縁部に絶縁ガスケット６を介在させ、両周縁部をかしめて密閉して作製した。 [Production of evaluation battery]
FIG. 2 shows a button type secondary battery as a configuration of the evaluation battery.
The
In the evaluation battery, the
以上の評価結果を表１に示した。実施例１～７から、本発明のＬｉイオン二次電池用負極材料を用いたＬｉイオン二次電池は、被膜が高いＬｉイオン導電性を有することからＳｉの容量減少が無く、電解液の還元分解が抑制され、さらに導電性結着物質によりＳｉ粒子自身の充電膨脹およびシングルミクロンの集合粒子により局所的な充電膨脹を抑制されるため、サイクル後の容量維持率が高いことが分かる。比較例１の被覆なしのＳｉ粒子は、電解液の分解が大きいためサイクル特性が悪い。比較例２は集合粒子の平均粒子径が大きいため電極膜の膨脹が増大しサイクル特性が悪い。比較例３は、結着物質に導電性が無いため電子伝導の抵抗が大きく容量が低い。
The above evaluation results are shown in Table 1. From Examples 1 to 7, the Li ion secondary battery using the negative electrode material for the Li ion secondary battery of the present invention has a high Li ion conductivity because the coating film has a high Li ion conductivity, and the electrolyte solution is reduced. It can be seen that since the decomposition is suppressed, and the charge expansion of the Si particles themselves and the local charge expansion are suppressed by the single micron aggregate particles by the conductive binder, the capacity retention rate after the cycle is high. The uncoated Si particles of Comparative Example 1 have poor cycle characteristics due to large decomposition of the electrolyte. In Comparative Example 2, since the average particle diameter of the aggregated particles is large, the expansion of the electrode film increases and the cycle characteristics are poor. In Comparative Example 3, since the binder material is not conductive, the resistance of electron conduction is large and the capacity is low.
本発明は、Ｌｉイオン伝導性が高く安定な、Ｌｉおよび他の特定の金属元素を含有するＬｉ含有酸化物の薄膜で活物質であるＳｉ粒子の表面を被覆し、さらにＬｉ含有酸化物被膜の表面を導電性の結着物質で拘束し、前記活物質の集合粒子の平均粒子径を０．５～１０μｍの細粒に調整することで、充電時に活物質による電解液の過剰な還元分解を充分に抑制でき、Ｓｉ粒子の充電膨脹を抑制できるため、黒鉛の理論充電容量を超える高い放電容量、優れたサイクル特性を示す負極材料を提供する。そのため、本発明のＬｉイオン用負極材料を用いるＬｉイオン二次電池は、近年の電池の高エネルギー密度化に対する要望を満たし、搭載する機器の小型化および高性能化に有用である。本発明のＬｉイオン用負極材料は、その特性を活かして、小型から大型までの高性能Ｌｉイオン二次電池に使用することができる。
In the present invention, the surface of Si particles as an active material is coated with a thin film of Li-containing oxide containing Li and other specific metal elements, which has a high Li ion conductivity and is stable. By constraining the surface with a conductive binder and adjusting the average particle diameter of the aggregated particles of the active material to a fine particle of 0.5 to 10 μm, excessive reductive decomposition of the electrolyte by the active material during charging can be achieved. Provided is a negative electrode material which can be sufficiently suppressed and can suppress charge expansion of Si particles, and thus exhibits a high discharge capacity exceeding the theoretical charge capacity of graphite and excellent cycle characteristics. Therefore, the Li ion secondary battery using the negative electrode material for Li ions of the present invention satisfies the recent demand for higher energy density of the battery, and is useful for downsizing and higher performance of the equipment to be mounted. The negative electrode material for Li ions of the present invention can be used for high-performance Li ion secondary batteries ranging from small to large, taking advantage of its characteristics.
１ 外装カップ
２ 負極合剤
３ 外装缶
４ 対極
５ セパレータ
６ 絶縁ガスケット
７ａ、７ｂ 集電体
１０Ａ，１０Ｂ 集合粒子
２０ Ｓｉ粒子
３０ Ｌｉ含有酸化物
４０ 導電性結着物質 DESCRIPTION OFSYMBOLS 1 Exterior cup 2 Negative electrode mixture 3 Exterior can 4 Counter electrode 5 Separator 6 Insulating gasket 7a, 7b Current collector 10A, 10B Aggregated particle 20 Si particle 30 Li-containing oxide 40 Conductive binder
２ 負極合剤
３ 外装缶
４ 対極
５ セパレータ
６ 絶縁ガスケット
７ａ、７ｂ 集電体
１０Ａ，１０Ｂ 集合粒子
２０ Ｓｉ粒子
３０ Ｌｉ含有酸化物
４０ 導電性結着物質 DESCRIPTION OF
Claims (4)
- Ｓｉ粒子表面に、Ｌｉと、Ｓｉ、Ａｌ、ＴｉおよびＺｒから選ばれる少なくとも一種の金属元素Ｍと、を含有する組成からなるＬｉ含有酸化物の被膜を有し、さらに前記被膜の表面に導電性の結着物質を有するＬｉイオン二次電池用負極材料であって、前記Ｌｉ含有酸化物の含有量が１０質量％以下であり、前記導電性結着物質の含有量が１０質量％以上であり、前記Ｌｉ含有酸化物の被膜および導電性の結着物質を有するＳｉ粒子が集合してなる集合粒子の平均粒子径が０．５～１０μｍであることを特徴とするＬｉイオン二次電池用負極材料。 The surface of the Si particle has a Li-containing oxide film having a composition containing Li and at least one metal element M selected from Si, Al, Ti, and Zr. A negative electrode material for a Li-ion secondary battery having a binder material, wherein the content of the Li-containing oxide is 10% by mass or less, and the content of the conductive binder material is 10% by mass or more. A negative electrode for a Li ion secondary battery, characterized in that an average particle diameter of aggregated particles formed by aggregating Si particles having a Li-containing oxide film and a conductive binder is 0.5 to 10 μm material.
- 前記導電性結着物質が、炭素を含有することを特徴とする、請求項１に記載のＬｉイオン二次電池用負極材料。 The negative electrode material for a Li ion secondary battery according to claim 1, wherein the conductive binder contains carbon.
- 請求項１または２に記載の負極材料を含有することを特徴とするＬｉイオン二次電池用負極。 A negative electrode for a Li ion secondary battery, comprising the negative electrode material according to claim 1 or 2.
- 請求項３に記載のＬｉイオン二次電池用負極を有することを特徴とするＬｉイオン二次電池。 A Li ion secondary battery comprising the negative electrode for a Li ion secondary battery according to claim 3.
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| JP2020068191A (en) * | 2017-12-27 | 2020-04-30 | 東ソー株式会社 | Composite active material for lithium secondary battery and manufacturing method thereof |
| CN113363445A (en) * | 2021-06-15 | 2021-09-07 | 广东凯金新能源科技股份有限公司 | Reticular gamma-alumina coated modified graphite negative electrode material, and preparation method and application thereof |
| WO2022113500A1 (en) * | 2020-11-30 | 2022-06-02 | パナソニックＩｐマネジメント株式会社 | Negative electrode material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
| WO2022163099A1 (en) * | 2021-01-29 | 2022-08-04 | パナソニックＩｐマネジメント株式会社 | Active material particle, electrochemical element, and electrochemical device |
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| WO2023162716A1 (en) * | 2022-02-28 | 2023-08-31 | パナソニックＩｐマネジメント株式会社 | Negative electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010073651A (en) * | 2008-09-22 | 2010-04-02 | Toshiba Corp | Negative electrode active material for nonaqueous electrolyte battery and nonaqueous electrolyte battery |
| JP2010140901A (en) * | 2008-12-09 | 2010-06-24 | Samsung Sdi Co Ltd | Anode active material for lithium secondary cell, method for manufacturing the same, and lithium secondary cell equipped with anode active material |
| WO2013140595A1 (en) * | 2012-03-23 | 2013-09-26 | 株式会社 東芝 | Negative electrode active material for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery, battery pack, and process for producing negative electrode active material for nonaqueous electrolyte secondary battery |
| JP2014029848A (en) * | 2012-06-29 | 2014-02-13 | Jfe Chemical Corp | Composite particle for lithium ion secondary battery negative electrode, method for producing the same, negative electrode for lithium ion secondary battery, and lithium ion secondary battery |
| JP2016506035A (en) * | 2012-12-05 | 2016-02-25 | サムスン エレクトロニクス カンパニー リミテッド | Surface-modified silicon nanoparticles for negative electrode active material and method for producing the same |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6256855B2 (en) * | 2014-07-15 | 2018-01-10 | 川上 総一郎 | Negative electrode material for secondary battery, electrode structure, secondary battery, and production method thereof |
-
2017
- 2017-04-03 WO PCT/JP2017/013962 patent/WO2017199606A1/en active Application Filing
- 2017-05-10 TW TW106115489A patent/TWI659559B/en active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010073651A (en) * | 2008-09-22 | 2010-04-02 | Toshiba Corp | Negative electrode active material for nonaqueous electrolyte battery and nonaqueous electrolyte battery |
| JP2010140901A (en) * | 2008-12-09 | 2010-06-24 | Samsung Sdi Co Ltd | Anode active material for lithium secondary cell, method for manufacturing the same, and lithium secondary cell equipped with anode active material |
| WO2013140595A1 (en) * | 2012-03-23 | 2013-09-26 | 株式会社 東芝 | Negative electrode active material for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery, battery pack, and process for producing negative electrode active material for nonaqueous electrolyte secondary battery |
| JP2014029848A (en) * | 2012-06-29 | 2014-02-13 | Jfe Chemical Corp | Composite particle for lithium ion secondary battery negative electrode, method for producing the same, negative electrode for lithium ion secondary battery, and lithium ion secondary battery |
| JP2016506035A (en) * | 2012-12-05 | 2016-02-25 | サムスン エレクトロニクス カンパニー リミテッド | Surface-modified silicon nanoparticles for negative electrode active material and method for producing the same |
Cited By (12)
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| JP7452599B2 (en) | 2017-12-27 | 2024-03-19 | 東ソー株式会社 | Composite active material for lithium secondary batteries |
| CN108539147A (en) * | 2018-03-21 | 2018-09-14 | 同济大学 | A kind of preparation method and application of lithium ion battery negative material SiO@Al@C |
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| WO2022113500A1 (en) * | 2020-11-30 | 2022-06-02 | パナソニックＩｐマネジメント株式会社 | Negative electrode material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
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| CN113363445A (en) * | 2021-06-15 | 2021-09-07 | 广东凯金新能源科技股份有限公司 | Reticular gamma-alumina coated modified graphite negative electrode material, and preparation method and application thereof |
| WO2023162689A1 (en) * | 2022-02-28 | 2023-08-31 | パナソニックＩｐマネジメント株式会社 | Negative electrode active material for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery |
| WO2023162716A1 (en) * | 2022-02-28 | 2023-08-31 | パナソニックＩｐマネジメント株式会社 | Negative electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery |
| WO2023175731A1 (en) * | 2022-03-15 | 2023-09-21 | 株式会社 東芝 | Electrode, battery, and battery pack |
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| TWI659559B (en) | 2019-05-11 |
| TW201742298A (en) | 2017-12-01 |
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