WO2019053984A1 - Negative electrode active substance comprising al-containing silicon material - Google Patents

Negative electrode active substance comprising al-containing silicon material Download PDF

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Publication number
WO2019053984A1
WO2019053984A1 PCT/JP2018/023077 JP2018023077W WO2019053984A1 WO 2019053984 A1 WO2019053984 A1 WO 2019053984A1 JP 2018023077 W JP2018023077 W JP 2018023077W WO 2019053984 A1 WO2019053984 A1 WO 2019053984A1
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Prior art keywords
negative electrode
containing silicon
silicon material
electrode active
active material
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PCT/JP2018/023077
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French (fr)
Japanese (ja)
Inventor
有貴 前原
隆弘 杉岡
敬史 毛利
真平 宗
泰弘 山口
正則 原田
石川　英明
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株式会社豊田自動織機
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Priority claimed from JP2018023383A external-priority patent/JP6852689B2/en
Application filed by 株式会社豊田自動織機 filed Critical 株式会社豊田自動織機
Publication of WO2019053984A1 publication Critical patent/WO2019053984A1/en

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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
    • C01B33/02—Silicon
    • 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
    • C01B33/06—Metal silicides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • 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

  • the present invention relates to a negative electrode active material containing an Al-containing silicon material.
  • silicon materials containing silicon as a main component are used as components of semiconductors, solar cells, secondary batteries and the like, and in recent years, research on silicon materials has been actively conducted.
  • Patent Document 1 and Patent Document 2 describe a lithium ion secondary battery in which the negative electrode active material is silicon.
  • Patent Document 3 and Patent Document 4 describe lithium ion secondary batteries in which the negative electrode active material is SiO.
  • Patent Document 5 describes that CaSi 2 is reacted with an acid to synthesize a layered polysilane, and it is described that a lithium ion secondary battery having the layered polysilane as a negative electrode active material exhibits a suitable capacity. It is done.
  • Patent Document 6 CaSi 2 is reacted with an acid to synthesize a layered polysilane, and the layered polysilane is heated at 300 ° C. or higher to produce a nanosilicon material from which hydrogen is released, and the nanosilicon material It is described that the lithium ion secondary battery which comprises as a negative electrode active material shows a suitable capacity
  • the inventor of the present invention has intensively examined trial and error repeatedly to provide a new silicon material. Since silicon itself is a semiconductor, when using a silicon material as a negative electrode active material of a secondary battery, the inventor considered that it is preferable to increase the conductivity of the silicon material by some method. Therefore, when a silicon material was manufactured by adding a small amount of Al, and the resistance of the secondary battery provided with the silicon material was measured, the resistance was low compared to the secondary battery provided with the Al-free silicon material. It turned out that it was resistance. The present inventors have completed the present invention based on such findings.
  • the negative electrode active material of the present invention is an Al-containing silicon material in which Al mass% (W Al %) satisfies 0 ⁇ W Al ⁇ 1 and Si mass% (W Si %) satisfies 60 ⁇ W Si ⁇ 90. It is characterized by including.
  • a suitable secondary battery By employing the negative electrode active material of the present invention, a suitable secondary battery can be provided.
  • the numerical range “x to y” described in the present specification includes the lower limit x and the upper limit y within the range. Then, the upper limit value and the lower limit value, and the numerical values listed in the examples can be combined arbitrarily to constitute a numerical range. Further, numerical values arbitrarily selected from within the numerical value range can be used as upper limit and lower limit numerical values.
  • an Al-containing silicon material (Al mass% (W Al %) satisfies 0 ⁇ W Al ⁇ 1 and Si mass% (W Si %) satisfies 60 ⁇ W Si ⁇ 90 (
  • the present invention is characterized by including the Al-containing silicon material of the present invention.
  • the Al-containing silicon material of the present invention can be said to be useful as a negative electrode active material for a low resistance secondary battery because the conductivity is improved due to the presence of Al.
  • a silicon material having too high an Al mass% is not preferable as a negative electrode active material.
  • W Al % preferably satisfies 0 ⁇ W Al ⁇ 0.8, preferably 0.01 ⁇ W Al ⁇ 0.8, and 0.05 ⁇ It is more preferable to satisfy W Al ⁇ 0.6, it is further preferable to satisfy 0.1 ⁇ W Al ⁇ 0.5, and it is particularly preferable to satisfy 0.15 ⁇ W Al ⁇ 0.5.
  • the negative electrode active material is a silicon material containing silicon
  • the silicon of the silicon material is oxidized by oxygen contained in the SEI film to be degraded.
  • the Al-containing silicon material of the present invention contains Al, it is considered that the oxidative deterioration of silicon is suppressed. The reason is that Al is considered to bind preferentially and stably to oxygen since it has lower electronegativity than silicon, and that Al-O bond of Al and oxygen is more stable than Si-O bond.
  • oxygen having a stable Al—O bond can be said to be less likely to be involved in the oxidation of silicon which is more electronegative than Al. Therefore, a secondary battery including the Al-containing silicon material of the present invention as a negative electrode active material can be expected to have a long life.
  • a silicon material means a material containing silicon as a main component.
  • the Si mass% (W Si %) in the Al-containing silicon material of the present invention preferably satisfies 70 ⁇ W Si ⁇ 85, and more preferably 80 ⁇ W Si ⁇ 85. If the Si mass% is too low, the capacity per unit mass of the Al-containing silicon material of the present invention will be low, so the capacity as a negative electrode active material may be insufficient. If the Si mass% is too high, the degree of expansion and contraction of the Al-containing silicon material of the present invention during charge and discharge becomes too large, and there is a concern that the Al-containing silicon material of the present invention may be broken.
  • Al-containing silicon material of the present invention may be present in the Al-containing silicon material of the present invention without departing from the spirit of the present invention.
  • Other elements include those derived from raw materials and production processes. Specific examples of other elements include Fe, O, Ca, C and halogen.
  • Fe wt% in Al-containing silicon material of the present invention is preferably satisfies 0 ⁇ W Fe ⁇ 3, more preferably satisfies 0 ⁇ W Fe ⁇ 1, 0 ⁇ W Fe ⁇ It is more preferable to satisfy 0.5, particularly preferably to satisfy 0 ⁇ W Fe ⁇ 0.3, and most preferably to satisfy 0 ⁇ W Fe ⁇ 0.1.
  • Fe mass% (W 2 Fe %) in the Al-containing silicon material of the present invention is 0 ⁇ W 2 Fe .
  • the relationship of Al mass% (W Al %) and Fe mass% (W Fe %) satisfies W Al > W Fe, and more preferably W Al > 2 ⁇ W Fe .
  • O wt% in Al-containing silicon material of the present invention (W O%) is preferably satisfies 5 ⁇ W O ⁇ 30, more preferably satisfies 10 ⁇ W O ⁇ 25, 12 ⁇ W O ⁇ It is further preferable to satisfy 22, and it is particularly preferable to satisfy 13 ⁇ W o ⁇ 21.
  • the Al-containing silicon material of the present invention contains a certain degree of oxygen, the life of a secondary battery including the Al-containing silicon material of the present invention as a negative electrode active material is extended.
  • Ca mass% in Al-containing silicon material of the present invention is preferably satisfies 0 ⁇ W Ca ⁇ 3, more preferably satisfies 0 ⁇ W Ca ⁇ 1, 0 ⁇ W Ca ⁇ It is further preferable to satisfy 0.5, and it is particularly preferable to satisfy 0 ⁇ W Ca ⁇ 0.3. In view of the ease of incorporation and removal of Ca , it is assumed that Ca mass% (W Ca %) in the Al-containing silicon material of the present invention is 0 ⁇ W Ca.
  • the halogen mass% (W x %) in the Al-containing silicon material of the present invention preferably satisfies 0 ⁇ W x ⁇ 3, more preferably 0 ⁇ W x ⁇ 2, and 0 ⁇ W x ⁇ It is more preferable to satisfy 1 and particularly preferable to satisfy 0 ⁇ W x ⁇ 0.5. In view of easiness of mixing and removal of halogen, it is assumed that the mass% (W x %) of halogen in the Al-containing silicon material of the present invention is 0 ⁇ W x .
  • the Al-containing silicon material of the present invention When the Al-containing silicon material of the present invention is described in terms of structure, it is preferable to have a structure in which a plurality of plate-like silicon bodies are stacked in the thickness direction.
  • the plate-like silicon body has a thickness for efficient insertion and desorption reaction of charge carriers such as lithium ions. Is preferably in the range of 10 nm to 100 nm, and more preferably in the range of 20 nm to 50 nm.
  • the length of the plate-like silicon body in the long axis direction is preferably in the range of 0.1 ⁇ m to 50 ⁇ m.
  • the plate-like silicon body preferably has a (longitudinal direction length) / (thickness) in the range of 2 to 1,000.
  • the Al-containing silicon material of the present invention preferably contains amorphous silicon or silicon crystallites.
  • the size of the silicon crystallite is preferably nano-sized.
  • the silicon crystallite size is preferably in the range of 0.5 nm to 300 nm, more preferably in the range of 1 nm to 100 nm, still more preferably in the range of 1 nm to 50 nm, particularly preferably in the range of 1 nm to 10 nm preferable.
  • X-ray diffraction measurement X-ray diffraction measurement
  • the Scheller equation using the half value width of the diffraction peak of the Si (111) plane of the obtained XRD chart Calculated from
  • the Al-containing silicon material of the present invention is preferably in the form of particles.
  • the average particle diameter of the Al-containing silicon material of the present invention is preferably in the range of 1 to 30 ⁇ m, more preferably in the range of 2 to 20 ⁇ m, and still more preferably in the range of 3 to 10 ⁇ m.
  • the average particle size when measured in conventional laser diffraction particle size distribution measuring apparatus, means D 50.
  • One aspect of a method of producing a negative electrode active material containing the Al-containing silicon material of the present invention is a) cooling the molten metal containing Ca, Al and Si to solidify it; b) reacting the solid with an acid to obtain a precursor of an Al-containing silicon material, c) heating the precursor at 300 ° C. or higher, It is characterized by including.
  • the above manufacturing method is suitable for manufacturing the Al-containing silicon material of the present invention having a structure in which a plurality of plate-like silicon bodies are stacked in the thickness direction.
  • An example of the chemical change in the steps a), b) and c) of the above-mentioned production method is as follows, which is represented by an ideal reaction equation ignoring Al. a) Process: Ca + 2 Si ⁇ Ca Si 2 b) Process: 3CaSi 2 + 6HCl ⁇ Si 6 H 6 + 3CaCl 2 c) Process: Si 6 H 6 ⁇ 6 Si + 3 H 2 ⁇
  • the laminated structure of the Al-containing silicon material of the present invention having a structure in which a plurality of plate-like silicon bodies are laminated in the thickness direction is considered to be derived from the Si layer in CaSi 2 or Si 6 H 6 .
  • the process will be described.
  • Ca, Al and Si used at a process a an element single-piece
  • CaSi 2 may be used as part of the raw material.
  • the elemental composition ratio of Ca and Si in the molten metal is preferably in the range of 1: 1.5 to 1: 2.5, more preferably in the range of 1: 1.8 to 1: 2.2, and 1: 1.
  • the range of 9 to 1: 2.1 is more preferable.
  • the amount of Al in the molten metal may be appropriately determined according to the Al mass ratio in the Al-containing silicon material of the present invention to be produced. However, since Al can be dissolved in an acid, the amount of Al in the precursor may be reduced in step b) of the next step. Therefore, it is preferable to add a little more Al to the molten metal.
  • step a Al is substituted solid solution CaSi 2-x Al x obtained by replacing the Si of CaSi 2 is manufactured. Therefore, the phase diagram of the solid solution was calculated using thermodynamic equilibrium calculation software (FactSage, Computational Mechanics Research Center, Inc.). A state diagram is shown in FIG.
  • x is in the range of 0 ⁇ x ⁇ 0.16.
  • the amount of Al in the composition formula of the substitutional solid solution at ordinary temperature is extremely low.
  • less than 4.5% of the mass% of Al based on the total mass of Ca, Si and Al in the molten metal is preferably within the range of 0.01 to 3%, and more preferably within the range of 0.05 to 2%. Is more preferably in the range of 0.1 to 1%.
  • an excessive addition of Al it is considered that CaAl 2 Si 2 also generates, CaAl 2 Si 2 disappears by decomposition in the next step of b) step.
  • the molten metal temperature in the step a) may be a temperature at which a mixture of Ca, Al and Si can be a molten metal.
  • the molten metal means a liquid-like state of a mixture of Ca, Al and Si.
  • the temperature of the molten metal is preferably in the range of 1050 ° C. to 1800 ° C., more preferably in the range of 1100 ° C. to 1500 ° C., and still more preferably in the range of 1200 ° C. to 1400 ° C.
  • a heating device used at a) process a high frequency induction heating device, an electric furnace, and a gas furnace can be used, for example.
  • the step a) may be performed under pressure or reduced pressure conditions, or under an inert gas atmosphere such as argon, helium or nitrogen.
  • the melt it is preferable to cool the melt at a rate as fast as possible.
  • the formation of the interstitial solid solution can also be expected.
  • the molten metal may be poured into a predetermined mold and left at room temperature, but a cooling method using a rapid cooling device may be used.
  • the rapid cooling device described in the present specification does not include a device for leaving and cooling the molten metal, but means a device for forcibly cooling the molten metal.
  • a cooling means such as melt span method, strip casting method, or melt spinning method
  • a cooling method such as an atomizing method for spraying a fluid onto a molten metal
  • the cooling device using the means can be illustrated.
  • a gas atomizing method, a water atomizing method, a centrifugal atomizing method, and a plasma atomizing method can be exemplified.
  • Specific rapid cooling devices include liquid rapid solidification devices, rapid cooling thin plate production devices, in-liquid spinning devices, gas atomizing devices, water atomizing devices, rotating disk devices, rotating electrode method devices (Nisshin Giken Co., Ltd.), liquid A quenching apparatus and a gas atomizing apparatus (above, Makabe Giken Co., Ltd.) can be exemplified.
  • As a preferable cooling rate 1000 to 100,000 ° C./second can be exemplified.
  • an annealing step may be added in which heating is performed while maintaining the solid state obtained by cooling. From the phase diagram of FIG. 1, it is considered that the substitutional solid solution CaSi 2 -xAl x is most likely to be formed at around 900 ° C. Therefore, the heating temperature in the annealing step is preferably 800 to 1000 ° C., and more preferably 850 to 950 ° C. The heating time may be, for example, 1 to 50 hours or 5 to 30 hours. Naturally, the solid is cooled after the annealing step.
  • the solid obtained by cooling may be crushed or further classified.
  • Step b) is a step of reacting the solid obtained in step a) with an acid to obtain a precursor of an Al-containing silicon material.
  • Precursor of Al-containing silicon material because the basic skeleton of Si layer by CaSi 2-x Al x or CaSi 2 is maintained, forms a lamellar.
  • hydrofluoric acid hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, methanesulfonic acid, tetrafluoroboric acid, hexafluorophosphoric acid, hexafluoro acid Arsenic acid, fluoroantimonic acid, hexafluorosilicic acid, hexafluorogermanic acid, hexafluorotin (IV) acid, trifluoroacetic acid, hexafluorotitanic acid, hexafluorozirconic acid, trifluoromethanesulfonic acid, fluorosulfonic acid are exemplified. Ru. These acids may be used alone or in combination.
  • the acid is preferably used in molar ratio in excess of Ca contained in the solid obtained in the step a).
  • the process may be carried out without a solvent, it is preferable to use water as a solvent from the viewpoint of separation of the target substance and removal of byproducts such as CaCl 2 and the like.
  • the reaction conditions in the same step are preferably reduced pressure conditions such as vacuum or under an inert gas atmosphere, and it is preferable to set temperature conditions below room temperature such as an ice bath. The reaction time of the same process may be set appropriately.
  • the step b) is preferably carried out in the presence of water, and Si 6 H 6 can be reacted with water. Therefore, in the step b), for example, the following reaction is considered to proceed. Si 6 H 6 + 3H 2 O ⁇ Si 6 H 3 (OH) 3 + 3H 2 ⁇
  • the precursor of the Al-containing silicon material may contain oxygen.
  • the element derived from the anion of the used acid may also be included.
  • the step c) is a step of heating the precursor of the Al-containing silicon material at 300 ° C. or higher to release hydrogen, water and the like to obtain the Al-containing silicon material.
  • the step c) is preferably carried out in a non-oxidizing atmosphere having a lower oxygen content than under normal atmosphere.
  • a non-oxidizing atmosphere a reduced pressure atmosphere including vacuum and an inert gas atmosphere can be exemplified.
  • the heating temperature is preferably in the range of 350 ° C. to 950 ° C., and more preferably in the range of 400 ° C. to 900 ° C. If the heating temperature is too low, hydrogen may not be sufficiently released, and if the heating temperature is too high, energy is wasted.
  • the heating time may be set appropriately according to the heating temperature. It is preferable to determine the heating time while measuring the amount of hydrogen and the like that escapes from the reaction system.
  • the heating temperature and the heating time By appropriately selecting the heating temperature and the heating time, the ratio of amorphous silicon and silicon crystallite contained in the Al-containing silicon material to be produced and the size of silicon crystallite can also be adjusted. By appropriately selecting the heating temperature and the heating time, it is also possible to prepare the shape of a nano-level thick layer including amorphous silicon and silicon crystallite contained in the Al-containing silicon material to be produced.
  • the obtained Al-containing silicon material may be crushed or further classified.
  • the Al-containing silicon material of the present invention can be used as a negative electrode active material of a storage battery such as a secondary battery such as a lithium ion secondary battery, an electric double layer capacitor, and a lithium ion capacitor.
  • a storage battery such as a secondary battery such as a lithium ion secondary battery, an electric double layer capacitor, and a lithium ion capacitor.
  • the Al-containing silicon material of the present invention can also be used as, for example, a material such as a CMOS, a semiconductor memory, and a solar cell, or as a photocatalytic material.
  • the lithium ion secondary battery of the present invention including the Al-containing silicon material of the present invention as a negative electrode active material will be described as a representative example of the power storage device.
  • the lithium ion secondary battery of the present invention includes a positive electrode, a negative electrode including the Al-containing silicon material of the present invention as a negative electrode active material, an electrolytic solution, and a separator.
  • the positive electrode has a current collector and a positive electrode active material layer bonded to the surface of the current collector.
  • the current collector refers to a chemically inert electron conductor for keeping current flowing to the electrode during discharge or charge of the lithium ion secondary battery.
  • As the current collector at least one selected from silver, copper, gold, aluminum, tungsten, cobalt, zinc, nickel, iron, platinum, tin, indium, titanium, ruthenium, tantalum, chromium, molybdenum, stainless steel, etc. A metal material can be illustrated.
  • the current collector may be coated with a known protective layer. What processed the surface of a collector by a well-known method may be used as a collector.
  • the current collector can take the form of a foil, a sheet, a film, a line, a rod, a mesh or the like. Therefore, as the current collector, for example, metal foils such as copper foil, nickel foil, aluminum foil, and stainless steel foil can be suitably used.
  • the thickness is preferably in the range of 1 ⁇ m to 100 ⁇ m.
  • the positive electrode active material layer contains a positive electrode active material and, if necessary, a conductive aid and / or a binder.
  • a positive electrode active material spinel such as LiMn 2 O 4 and a solid solution composed of a mixture of spinel and layered compound, LiMPO 4 , LiMVO 4 or Li 2 MSiO 4 (M in the formula is Co, Ni, Mn, Polyanionic compounds represented by (at least one of Fe) and the like can be mentioned.
  • tavorite compound (the M a transition metal) LiMPO 4 F, such as LiFePO 4 F represented by, Limbo 3 such LiFeBO 3 (M is a transition metal) include borate-based compound represented by be able to.
  • any metal oxide used as a positive electrode active material may have the above composition formula as a basic composition, and one obtained by substituting a metal element contained in the basic composition with another metal element can also be used as a positive electrode active material .
  • a positive electrode active material a positive electrode active material containing no lithium ion contributing to charge and discharge, for example, a simple substance of sulfur, a compound of sulfur and carbon, a metal sulfide such as TiS 2 , V 2 O 5 , MnO Oxides such as 2 , polyaniline and anthraquinone, and compounds containing these aromatics in the chemical structure, conjugated materials such as conjugated diacetic acid organic substances, and other known materials can also be used.
  • a compound having a stable radical such as nitroxide, nitronyl nitroxide, galvinoxyl, phenoxyl or the like may be adopted as the positive electrode active material.
  • a positive electrode active material containing no lithium it is necessary to add ions to the positive electrode and / or the negative electrode by a known method.
  • a metal or a compound containing the ions may be used.
  • a conductive aid is added to enhance the conductivity of the electrode. Therefore, the conductive additive may be optionally added when the conductivity of the electrode is insufficient, and may not be added when the conductivity of the electrode is sufficiently excellent.
  • the conductive auxiliary agent may be any chemically active high electron conductor, and carbon black particles such as carbon black, graphite, acetylene black, ketjen black (registered trademark), vapor grown carbon fiber (vapor grown carbon) Fiber), and various metal particles are exemplified. These conductive assistants can be added to the active material layer singly or in combination of two or more.
  • the binder plays the role of anchoring the active material and the conductive aid to the surface of the current collector and maintaining the conductive network in the electrode.
  • the binder may, for example, be a fluorine-containing resin such as polyvinylidene fluoride, polytetrafluoroethylene or fluororubber, a thermoplastic resin such as polypropylene or polyethylene, an imide resin such as polyimide or polyamideimide, an alkoxysilyl group-containing resin, Examples of acrylic resins such as acrylic acid, styrene-butadiene rubber (SBR), alginates such as carboxymethylcellulose, sodium alginate and ammonium alginate, water-soluble cellulose ester cross-linked product, starch-acrylic acid graft polymer it can. These binders may be used alone or in combination.
  • a crosslinked polymer in which a carboxyl group-containing polymer such as polyacrylic acid or polymethacrylic acid as disclosed in WO 2016/063882 is crosslinked with a polyamine such as diamine may be used as a binder.
  • diamine used for the cross-linked polymer examples include alkylene diamines such as ethylene diamine, propylene diamine and hexamethylene diamine, 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, isophorone diamine, bis (4-aminocyclohexyl) methane and the like.
  • Saturated carbocyclic ring diamine m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylether, bis (4-aminophenyl) sulfone, benzidine, o-tolidine, 2,4- Aromatic diamines such as tolylene diamine, 2,6-tolylene diamine, xylylene diamine and naphthalene diamine can be mentioned.
  • the blending ratio of the binder in the active material layer is, in mass ratio, preferably active material: binder 1: 0.001 to 1: 0.3, 1: 0.005 to 1: 0 It is more preferably 0.2, and more preferably 1: 0.01 to 1: 0.15.
  • the negative electrode includes a current collector and a negative electrode active material layer bonded to the surface of the current collector.
  • As the current collector one described for the positive electrode may be appropriately adopted appropriately.
  • the negative electrode active material layer contains a negative electrode active material and, if necessary, a conductive aid and / or a binder.
  • the negative electrode active material only the Al-containing silicon material of the present invention may be employed, or the Al-containing silicon material of the present invention may be used in combination with a known negative electrode active material. What coated Al content silicon material of the present invention with carbon may be used as a cathode active material.
  • C mass% (W C %) preferably satisfies 0 ⁇ W C ⁇ 30, 1 ⁇ W C ⁇ 20. Is more preferable, 2 ⁇ W c ⁇ 15 is more preferable, and 5 ⁇ W c ⁇ 10 is particularly preferable.
  • those described for the positive electrode may be appropriately adopted at the same mixing ratio.
  • an active material layer on the surface of a current collector current collection can be performed using conventionally known methods such as roll coating, die coating, dip coating, doctor blade method, spray coating, and curtain coating.
  • the active material may be applied to the surface of the body.
  • the active material, the solvent, and, if necessary, the binder and / or the conductive auxiliary agent are mixed to prepare a slurry.
  • the solvent include N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone and water.
  • the slurry is applied to the surface of a current collector and then dried. The dried one may be compressed to increase the electrode density.
  • the electrolytic solution contains a non-aqueous solvent and an electrolyte dissolved in the non-aqueous solvent.
  • cyclic esters As the non-aqueous solvent, cyclic esters, linear esters, ethers and the like can be used.
  • examples of cyclic esters include ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, gamma-butyrolactone, vinylene carbonate, 2-methyl-gamma-butyrolactone, acetyl-gamma-butyrolactone and gamma-valerolactone.
  • chain ester examples include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, ethyl methyl carbonate, alkyl propionic acid ester, malonic acid dialkyl ester, acetic acid alkyl ester and the like.
  • ethers tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane can be exemplified.
  • non-aqueous solvent a compound in which part or all of hydrogens in the chemical structure of the above specific solvent is substituted with fluorine may be adopted.
  • Examples of the electrolyte include lithium salts such as LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiCF 3 SO 3 , and LiN (CF 3 SO 2 ) 2 .
  • lithium salts such as LiClO 4 , LiPF 6 , LiBF 4 , LiCF 3 SO 3 and the like in a nonaqueous solvent such as fluoroethylene carbonate, ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate, propylene carbonate, diethyl carbonate
  • a nonaqueous solvent such as fluoroethylene carbonate, ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate, propylene carbonate, diethyl carbonate
  • the separator separates the positive electrode and the negative electrode, and allows lithium ions to pass while preventing a short circuit due to the contact of the both electrodes.
  • synthetic resins such as polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamide, polyaramid (Aromatic polyamide), polyester, polyacrylonitrile, etc., polysaccharides such as cellulose and amylose, natural substances such as fibroin, keratin, lignin and suberin Examples thereof include porous bodies, non-woven fabrics, and woven fabrics using one or more kinds of electrically insulating materials such as polymers and ceramics.
  • the separator may have a multilayer structure.
  • a separator is sandwiched between the positive electrode and the negative electrode as necessary to form an electrode body.
  • the electrode body may be any of a laminated type in which the positive electrode, the separator and the negative electrode are stacked, or a wound type in which the positive electrode, the separator and the negative electrode are wound.
  • the shape of the lithium ion secondary battery of the present invention is not particularly limited, and various shapes such as cylindrical, square, coin, and laminate types can be adopted.
  • the lithium ion secondary battery of the present invention may be mounted on a vehicle.
  • the vehicle may be a vehicle using electric energy from a lithium ion secondary battery for all or part of its power source, and may be, for example, an electric vehicle, a hybrid vehicle, or the like.
  • a lithium ion secondary battery is mounted on a vehicle, a plurality of lithium ion secondary batteries may be connected in series to form a battery pack.
  • various household appliances driven by a battery such as a personal computer and a mobile communication apparatus, as well as a vehicle, an office apparatus, an industrial apparatus and the like can be mentioned.
  • the lithium ion secondary battery of the present invention can be used in wind power generation, solar power generation, hydroelectric power generation, storage devices and power smoothing devices for electric power systems, power sources for power and / or accessories of ships, etc., aircraft, Power supply source for power of spacecraft and / or accessories, auxiliary power supply for vehicles not using electricity as power source, power supply for mobile home robots, power supply for system backup, power supply for uninterruptible power supply, You may use for the electrical storage apparatus which stores temporarily the electric power required for charge in the charge station etc. for electric vehicles.
  • Example 1 The Al-containing silicon material and lithium ion secondary battery of Example 1 were manufactured as follows.
  • Step Ca, Al and Si were weighed in a carbon crucible.
  • the elemental composition ratio of Ca and Si was 1: 2, and the amount of Al added was 1% with respect to the total mass of Ca, Al and Si.
  • a carbon crucible was heated at around 1300 ° C. in a high frequency induction heating apparatus under an argon gas atmosphere to obtain a molten metal containing Ca, Al and Si.
  • the molten metal is poured into a predetermined mold to cool and solidify.
  • the solid was pulverized into a powder and then subjected to the step b).
  • Example 1 Process The Al-containing silicon material of Example 1 was manufactured by heating the precursor of the Al-containing silicon material at 900 ° C. for 1 hour under a nitrogen gas atmosphere.
  • Example 1 Using the Al-containing silicon material of Example 1, the negative electrode of Example 1 and the lithium ion secondary battery of Example 1 were produced as follows.
  • a polyacrylic acid having a weight average molecular weight of 800,000 was dissolved in N-methyl-2-pyrrolidone to prepare a polyacrylic acid solution containing 10% by mass of polyacrylic acid.
  • a solution of 4,4'-diaminodiphenylmethane was prepared by dissolving 0.2 g (1.0 mmol) of 4,4'-diaminodiphenylmethane in 0.4 mL of N-methyl-2-pyrrolidone.
  • Example 1 72.5 parts by mass of the Al-containing silicon material of Example 1 as a negative electrode active material, 13.5 parts by mass of acetylene black as a conduction aid, and 14 parts by mass of a solid content as a binder And, an appropriate amount of N-methyl-2-pyrrolidone was mixed to prepare a slurry.
  • a copper foil was prepared as a current collector for the negative electrode.
  • the slurry was applied in the form of a film on the surface of the copper foil using a doctor blade.
  • the copper foil coated with the slurry was dried at 80 ° C. for 15 minutes to remove N-methyl-2-pyrrolidone. Thereafter, the resultant was pressed and heated at 180 ° C. for 30 minutes in a reduced pressure atmosphere using a vacuum pump to manufacture the negative electrode of Example 1 in which the negative electrode active material layer was formed.
  • a polyethylene porous membrane was prepared as a separator.
  • a solution in which LiPF 6 was dissolved at a concentration of 2 mol / L in a mixed solvent in which fluoroethylene carbonate and ethyl methyl carbonate were mixed at a volume ratio of 19: 81 was used as an electrolytic solution.
  • Comparative example 1 In the step a), the silicon material of Comparative Example 1, the negative electrode of Comparative Example 1, and the lithium ion secondary battery of Comparative Example 1 were produced in the same manner as in Example 1 except that Al was not added.
  • Elemental analysis of the Al-containing silicon material of Example 1 and the silicon material of Comparative Example 1 was performed using an inductively coupled plasma atomic emission spectrometer (ICP-AES). As a result of elemental analysis, the Al mass% in the Al-containing silicon material of Example 1 is 0.25% and the Fe mass% is 0%, and the Al mass% in the silicon material of Comparative Example 1 is 0%, Fe mass% It was 0%.
  • ICP-AES inductively coupled plasma atomic emission spectrometer
  • the lithium ion secondary battery of Example 1 was adjusted to an SOC (State of Charge) of 15% in a thermostat of 25 ° C. Then, the lithium ion secondary battery was discharged for 10 seconds at a constant current of 1 C rate. The resistance was calculated by dividing the amount of change in voltage before and after discharge by the current value. The same test was performed on the lithium ion secondary battery of Comparative Example 1. The resistance of the lithium ion secondary battery of Example 1 was 3.3 ⁇ , and the resistance of the lithium ion secondary battery of Comparative Example 1 was 3.6 ⁇ . It was confirmed that the resistance of the lithium ion secondary battery is lowered by using the Al-containing silicon material.
  • SOC State of Charge
  • Example 2 The Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 2 were manufactured as follows.
  • Step Ca Al and Si were weighed in a carbon crucible.
  • the elemental composition ratio of Ca and Si was 1: 2, and the amount of Al added was 1% with respect to the total mass of Ca, Al and Si.
  • a carbon crucible was heated at around 1300 ° C. in a high frequency induction heating apparatus under an argon gas atmosphere to obtain a molten metal containing Ca, Al and Si.
  • the molten metal is poured into a predetermined mold and cooled to form a solid.
  • the solid was pulverized into a powder and then subjected to the step b).
  • Step 2 The Al-containing silicon material of Example 2 was manufactured by heating the precursor of the Al-containing silicon material at 900 ° C. for 1 hour in a nitrogen gas atmosphere.
  • Example 2 Using the Al-containing silicon material of Example 2, the negative electrode of Example 2 and the lithium ion secondary battery of Example 2 were manufactured as follows.
  • a polyacrylic acid having a weight average molecular weight of 800,000 was dissolved in N-methyl-2-pyrrolidone to prepare a polyacrylic acid solution containing 10% by mass of polyacrylic acid.
  • a solution of 4,4'-diaminodiphenylmethane was prepared by dissolving 0.2 g (1.0 mmol) of 4,4'-diaminodiphenylmethane in 0.4 mL of N-methyl-2-pyrrolidone.
  • Example 2 72.5 parts by mass of the Al-containing silicon material of Example 2 as a negative electrode active material, 13.5 parts by mass of acetylene black as a conduction aid, and 14 parts by mass of a solid content as a binder And, an appropriate amount of N-methyl-2-pyrrolidone was mixed to prepare a slurry.
  • a copper foil was prepared as a current collector for the negative electrode.
  • the slurry was applied in the form of a film on the surface of the copper foil using a doctor blade.
  • the copper foil coated with the slurry was dried at 80 ° C. for 15 minutes to remove N-methyl-2-pyrrolidone. After that, pressing was performed and heating was performed at 180 ° C. for 30 minutes in a reduced pressure atmosphere using a vacuum pump to manufacture the negative electrode of Example 2 in which the negative electrode active material layer was formed.
  • the negative electrode of Example 2 was cut to a diameter of 11 mm to obtain an evaluation electrode.
  • a metal lithium foil having a thickness of 500 ⁇ m was cut to a diameter of 13 mm and used as a counter electrode.
  • a glass filter (Hoechst Celanese) and celgard 2400 (Polypore Co., Ltd.) which is a single-layer polypropylene were prepared as a separator.
  • the volume ratio of ethylene carbonate and diethyl carbonate 1: LiPF 6 was prepared the electrolytic solution at a concentration 1 mol / L in a mixed solvent obtained by mixing 1.
  • the two types of separators were sandwiched between the counter electrode and the evaluation electrode in the order of the counter electrode, the glass filter, celgard 2400, and the evaluation electrode to form an electrode body.
  • the electrode body was housed in a coin-type battery case CR2032 (Housen Co., Ltd.), and an electrolyte was further injected to obtain a coin-type battery.
  • the resultant was used as a lithium ion secondary battery of Example 2.
  • Example 3 The following carbon coating process was added after the process c) with the point of increasing the production scale, and the carbon-coated Al-containing silicon material was used as the Al-containing silicon material of Example 3 and was used as a negative electrode active material.
  • the Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 3 were manufactured in the same manner as in Example 2 except for the point.
  • Step c) The Al-containing silicon material obtained in step c) is placed in a rotary kiln type reactor, and thermal CVD is performed at 880 ° C. for 60 minutes under aeration of propane-argon mixed gas, thereby carbon coating An Al-containing silicon material was obtained.
  • Example 4 Powdered CaSi 2 containing Al and Fe as impurities was prepared.
  • elemental analysis of the CaSi 2 was performed using ICP-AES, it was 38 mass% of Ca, 57 mass% of Si, 4 mass% of Fe, and 1 mass% of Al.
  • the Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 4 were manufactured in the same manner as in Example 3 except that step b) and the following steps were performed using the CaSi 2 .
  • Comparative example 2 The silicon material, the negative electrode, and the lithium ion secondary battery of Comparative Example 2 were manufactured in the same manner as in Example 2 except that Al was not added in the step a).
  • Comparative example 3 (Comparative example 3)
  • the silicon material, the negative electrode, and the lithium ion secondary battery of Comparative Example 3 were manufactured in the same manner as in Example 2 except that Al was not added and Fe was added.
  • Fe in the step a) was added in an amount of 4% with respect to the total mass of Ca, Fe and Si.
  • Elemental analysis was performed on the Al-containing silicon materials of Examples 2 to 4 and the silicon materials of Comparative Examples 2 and 3 using a fluorescent X-ray analyzer (XRF).
  • elemental analysis of oxygen was performed on the Al-containing silicon materials of Examples 2 to 4 and the silicon materials of Comparative Examples 2 and 3 using an oxygen / nitrogen / hydrogen analyzer.
  • elemental analysis for carbon was performed on the carbon-coated Al-containing silicon materials of Example 3 and Example 4 using a carbon / sulfur analyzer.
  • Example 2 The results of these elemental analyzes are shown in Table 1 as mass%.
  • the presence of a slight amount of Fe in Example 2, Example 3, and Comparative Example 2 is because Fe is contained as an impurity in the metal of the raw material.
  • O, Ca and Cl contained in all silicon materials are derived from the solvent (water) used in the production, the raw material, the anion of the acid and the like.
  • Initial efficiency (%) 100 ⁇ (initial charge capacity) / (initial discharge capacity)
  • Capacity retention rate (%) 100 ⁇ (charge capacity at each cycle) / (charge capacity at first cycle)
  • Example 5 The Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 5 were produced as follows.
  • Step Ca Al and Si were weighed in a carbon crucible.
  • the elemental composition ratio of Ca and Si was 1: 2, and the amount of Al added was 0.1% with respect to the total mass of Ca, Al and Si.
  • a carbon crucible was heated at around 1300 ° C. in a high frequency induction heating apparatus under an argon gas atmosphere to obtain a molten metal containing Ca, Al and Si.
  • the molten metal is poured into a predetermined mold and cooled to form a solid.
  • the solid was pulverized into a powder and then subjected to the step b).
  • Step 5 The Al-containing silicon material precursor of Example 5 was manufactured by heating the precursor of the Al-containing silicon material at 900 ° C. for 1 hour in a nitrogen gas atmosphere.
  • Example 5 The negative electrode of Example 5 and the lithium ion secondary battery of Example 5 were manufactured as follows using the Al-containing silicon material of Example 5.
  • a polyacrylic acid having a weight average molecular weight of 800,000 was dissolved in N-methyl-2-pyrrolidone to prepare a polyacrylic acid solution containing 10% by mass of polyacrylic acid.
  • a solution of 4,4'-diaminodiphenylmethane was prepared by dissolving 0.2 g (1.0 mmol) of 4,4'-diaminodiphenylmethane in 0.4 mL of N-methyl-2-pyrrolidone.
  • Example 5 72.5 parts by mass of the Al-containing silicon material of Example 5 as a negative electrode active material, 13.5 parts by mass of acetylene black as a conduction aid, and 14 parts by mass of solid content as a binder And, an appropriate amount of N-methyl-2-pyrrolidone was mixed to prepare a slurry.
  • a copper foil was prepared as a current collector for the negative electrode.
  • the slurry was applied in the form of a film on the surface of the copper foil using a doctor blade.
  • the copper foil coated with the slurry was dried at 80 ° C. for 15 minutes to remove N-methyl-2-pyrrolidone. After that, pressing was performed and heating was performed at 180 ° C. for 30 minutes in a reduced pressure atmosphere using a vacuum pump to manufacture the negative electrode of Example 5 in which the negative electrode active material layer was formed.
  • the negative electrode of Example 5 was cut to a diameter of 11 mm to obtain an evaluation electrode.
  • a metal lithium foil having a thickness of 500 ⁇ m was cut to a diameter of 13 mm and used as a counter electrode.
  • a glass filter (Hoechst Celanese) and celgard 2400 (Polypore Co., Ltd.) which is a single-layer polypropylene were prepared as a separator.
  • the volume ratio of ethylene carbonate and diethyl carbonate 1: LiPF 6 was prepared the electrolytic solution at a concentration 1 mol / L in a mixed solvent obtained by mixing 1.
  • the two types of separators were sandwiched between the counter electrode and the evaluation electrode in the order of the counter electrode, the glass filter, celgard 2400, and the evaluation electrode to form an electrode body.
  • the electrode body was housed in a coin-type battery case CR2032 (Housen Co., Ltd.), and an electrolyte was further injected to obtain a coin-type battery.
  • the resultant was used as a lithium ion secondary battery of Example 5.
  • Example 6 Al-containing silicon material of Example 6, negative electrode in the same manner as in Example 5 except that in the step a), the amount of Al added is 0.3% with respect to the total mass of Ca, Al and Si And a lithium ion secondary battery.
  • Example 7 Al-containing silicon material of Example 7, negative electrode in the same manner as in Example 5 except that in the step a), the amount of Al added is 0.5% with respect to the total mass of Ca, Al and Si And a lithium ion secondary battery.
  • Example 8 Al-containing silicon material, negative electrode and lithium of Example 8 in the same manner as in Example 5 except that in the step a), the amount of Al added is 1% with respect to the total mass of Ca, Al and Si An ion secondary battery was manufactured.
  • Example 9 The Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 9 were manufactured in the same manner as in Example 8 except that the following annealing step was added to the step a).
  • Elemental analysis of the Al-containing silicon materials of Examples 5 to 9 was performed in the same manner as in Evaluation Example 3. The results of these elemental analyzes are shown in Table 3 as mass%.
  • the reason why a small amount of Fe is present in the Al-containing silicon material of each example is that Fe is contained as an impurity in the metal of the raw material.
  • Cl, Ca, C and O contained in the Al-containing silicon material of each example are derived from the anion of the acid used in the production, the raw material, the carbon crucible, the solvent (water) and the like.
  • Example 7 The lithium ion secondary batteries of Example 5 to Example 9 were discharged to 0.01 V at a current of 0.2 mA and then charged to 1.0 V at a current of 0.2 mA. went. Furthermore, for the lithium ion secondary batteries of Example 5 to Example 9 after the initial charge and discharge, discharging to 0.01 V with a current of 0.5 mA and then charging to 1.0 V with a current of 0.5 mA The charge and discharge cycle of 50 cycles was performed. In addition, the lithium ion secondary batteries of Examples 5 to 9 were discharged to 0.01 V at a current of 0.2 mA, and then charged to 0.8 V at a current of 0.2 mA. Discharge was done.
  • Initial efficiency (%) 100 ⁇ (initial charge capacity) / (initial discharge capacity)
  • Capacity retention rate (%) 100 ⁇ (charge capacity at 50 cycles) / (charge capacity at first cycle)
  • the results of the initial discharge capacity, the initial charge capacity (1.0 V and 0.8 V), the initial efficiency (1.0 V and 0.8 V), and the capacity retention rate are shown in Tables 4 and 5 together with the results of Al mass%.
  • Example 10 The Al-containing silicon material of Example 10 was produced as follows.
  • Step Ca, Al and Si were weighed in a carbon crucible.
  • the elemental composition ratio of Ca and Si was 1: 2, and the amount of Al added was 1% with respect to the total mass of Ca, Al and Si.
  • a carbon crucible was heated at around 1300 ° C. in a high frequency induction heating apparatus under an argon gas atmosphere to obtain a molten metal containing Ca, Al and Si.
  • the molten metal is poured into a predetermined mold to cool and solidify.
  • the solid was pulverized into a powder and then subjected to the step b).
  • Step c) Step The precursor of the Al-containing silicon material was heated at 900 ° C. for 1 hour in a nitrogen gas atmosphere to produce an Al-containing silicon material.
  • Step c) The Al-containing silicon material obtained in step c) is placed in a rotary kiln type reactor, and thermal CVD is performed at 880 ° C. for 60 minutes under aeration of propane-argon mixed gas, thereby carbon coating An Al-containing silicon material was obtained. This carbon-coated Al-containing silicon material was used as the Al-containing silicon material of Example 10.
  • Example 10 The negative electrode of Example 10 and the lithium ion secondary battery of Example 10 were manufactured as follows using the Al-containing silicon material of Example 10.
  • Example 10 80.8 parts by mass of the Al-containing silicon material of Example 10 as a negative electrode active material, 10.2 parts by mass of acetylene black as a conduction aid, 9 parts by mass of polyamideimide as a binder, and an appropriate amount of N-methyl-2-
  • the pyrrolidone was mixed to produce a slurry.
  • a copper foil was prepared as a current collector for the negative electrode.
  • the slurry was applied in the form of a film on the surface of the copper foil using a doctor blade.
  • the copper foil coated with the slurry was dried at 80 ° C. for 15 minutes to remove N-methyl-2-pyrrolidone.
  • the negative electrode was pressed and heated at 180 ° C. for 30 minutes in a reduced pressure atmosphere using a vacuum pump to manufacture the negative electrode of Example 10 in which the negative electrode active material layer was formed.
  • a slurry was prepared by mixing 3 parts by mass of vinylidene and an appropriate amount of N-methyl-2-pyrrolidone.
  • An aluminum foil was prepared as a positive electrode current collector. The slurry was applied in the form of a film on the surface of the aluminum foil using a doctor blade. The N-methyl-2-pyrrolidone was removed by drying the slurry-coated aluminum foil at 80 ° C. for 20 minutes. Then, the resultant was pressed and heated at 120 ° C. for 6 hours in a reduced pressure atmosphere using a vacuum pump to manufacture a positive electrode having a positive electrode active material layer formed on the surface of the current collector.
  • a polyethylene porous membrane was prepared as a separator. Further, a solution in which LiPF 6 was dissolved at a concentration of 2 mol / L in a mixed solvent in which dimethyl carbonate and fluoroethylene carbonate were mixed at a volume ratio of 81:19 was used as an electrolytic solution.
  • Example 10 It laminated
  • the laminate and the electrolytic solution were housed in a laminate film bag, the bag was sealed, and the lithium ion secondary battery of Example 10 was manufactured.
  • the Al-containing silicon material of the present invention is excellent in thermal stability in a charged state due to the presence of Al.

Abstract

Provided is a new silicon material. The invention is a negative electrode active substance characterized by comprising an Al-containing silicon material wherein the percentage by mass for Al (WAl%) satisfies 0 < WAl < 1 and the percentage by mass for Si (WSi%) satisfies 60 ≤ WSi ≤ 90.

Description

Ａｌ含有シリコン材料を含む負極活物質Negative electrode active material containing Al-containing silicon material
　本発明は、Ａｌ含有シリコン材料を含む負極活物質に関するものである。 The present invention relates to a negative electrode active material containing an Al-containing silicon material.
　シリコンを主な構成成分とするシリコン材料は半導体、太陽電池、二次電池などの構成要素として用いられることが知られており、そして、近年、シリコン材料に関する研究が活発に行われている。 It is known that silicon materials containing silicon as a main component are used as components of semiconductors, solar cells, secondary batteries and the like, and in recent years, research on silicon materials has been actively conducted.
　例えば、特許文献１及び特許文献２には、負極活物質がシリコンであるリチウムイオン二次電池が記載されている。
　特許文献３及び特許文献４には、負極活物質がＳｉＯであるリチウムイオン二次電池が記載されている。 For example, Patent Document 1 and Patent Document 2 describe a lithium ion secondary battery in which the negative electrode active material is silicon.
Patent Document 3 and Patent Document 4 describe lithium ion secondary batteries in which the negative electrode active material is SiO.
　特許文献５には、ＣａＳｉ２を酸と反応させて層状ポリシランを合成することが記載されており、当該層状ポリシランを負極活物質として具備するリチウムイオン二次電池が好適な容量を示すことが記載されている。 Patent Document 5 describes that CaSi 2 is reacted with an acid to synthesize a layered polysilane, and it is described that a lithium ion secondary battery having the layered polysilane as a negative electrode active material exhibits a suitable capacity. It is done.
　特許文献６には、ＣａＳｉ２を酸と反応させて層状ポリシランを合成し、当該層状ポリシランを３００℃以上で加熱して水素を離脱させたナノシリコン材料を製造したこと、及び、当該ナノシリコン材料を負極活物質として具備するリチウムイオン二次電池が好適な容量維持率を示すことが記載されている。 In Patent Document 6, CaSi 2 is reacted with an acid to synthesize a layered polysilane, and the layered polysilane is heated at 300 ° C. or higher to produce a nanosilicon material from which hydrogen is released, and the nanosilicon material It is described that the lithium ion secondary battery which comprises as a negative electrode active material shows a suitable capacity | capacitance maintenance factor.
特開２０１４－２０３５９５号公報JP 2014-203595 特開２０１５－５７７６７号公報JP, 2015-57767, A 特開２０１５－１８５５０９号公報JP, 2015-185509, A 特開２０１５－１７９６２５号公報JP, 2015-179625, A 特開２０１１－０９０８０６号公報JP, 2011-090806, A 国際公開第２０１４／０８０６０８号International Publication No. 2014/080608
　上述したように、シリコン材料の研究が熱心に行われており、そして、半導体、太陽電池、二次電池などの技術分野において、新しいシリコン材料の提供が熱望されている。本発明は、かかる事情に鑑みて為されたものであり、新しいシリコン材料を提供することを目的とする。 As described above, research on silicon materials is being carried out vigorously, and there is a keen desire to provide new silicon materials in the technical fields such as semiconductors, solar cells, secondary batteries and the like. The present invention has been made in view of such circumstances, and an object thereof is to provide a new silicon material.
　本発明者は、新しいシリコン材料を提供すべく、試行錯誤を繰り返して鋭意検討した。シリコン自体は半導体であるため、シリコン材料を二次電池の負極活物質として利用する場合、何らかの方法でシリコン材料の導電性を高くするのが好ましいと本発明者は考えた。そこで、若干量のＡｌを添加してシリコン材料を製造し、当該シリコン材料を具備する二次電池の抵抗を測定したところ、Ａｌ無添加のシリコン材料を具備する二次電池と比較して、低抵抗であることを知見した。本発明者はかかる知見に基づき本発明を完成させた。 The inventor of the present invention has intensively examined trial and error repeatedly to provide a new silicon material. Since silicon itself is a semiconductor, when using a silicon material as a negative electrode active material of a secondary battery, the inventor considered that it is preferable to increase the conductivity of the silicon material by some method. Therefore, when a silicon material was manufactured by adding a small amount of Al, and the resistance of the secondary battery provided with the silicon material was measured, the resistance was low compared to the secondary battery provided with the Al-free silicon material. It turned out that it was resistance. The present inventors have completed the present invention based on such findings.
　本発明の負極活物質は、Ａｌ質量％（ＷＡｌ％）が０＜ＷＡｌ＜１を満足し、Ｓｉ質量％（ＷＳｉ％）が６０≦ＷＳｉ≦９０を満足するＡｌ含有シリコン材料を含むことを特徴とする。 The negative electrode active material of the present invention is an Al-containing silicon material in which Al mass% (W Al %) satisfies 0 <W Al <1 and Si mass% (W Si %) satisfies 60 ≦ W Si ≦ 90. It is characterized by including.
　本発明の負極活物質を採用することで、好適な二次電池を提供できる。 By employing the negative electrode active material of the present invention, a suitable secondary battery can be provided.
置換型固溶体ＣａＳｉ２－ｘＡｌｘの状態図である。It is a phase diagram of substitution type solid solution CaSi 2-x Al x . 実施例２、比較例２及び比較例３のリチウムイオン二次電池についての、容量維持率の結果（Ｎ＝２）を示すグラフである。It is a graph which shows the result (N = 2) of the capacity | capacitance maintenance factor about the lithium ion secondary battery of Example 2, the comparative example 2, and the comparative example 3. FIG.
　以下に、本発明を実施するための最良の形態を説明する。なお、特に断らない限り、本明細書に記載された数値範囲「ｘ～ｙ」は、下限ｘおよび上限ｙをその範囲に含む。そして、これらの上限値および下限値、ならびに実施例中に列記した数値も含めてそれらを任意に組み合わせることで数値範囲を構成し得る。さらに数値範囲内から任意に選択した数値を上限、下限の数値とすることができる。 Hereinafter, the best mode for carrying out the present invention will be described. Unless otherwise specified, the numerical range “x to y” described in the present specification includes the lower limit x and the upper limit y within the range. Then, the upper limit value and the lower limit value, and the numerical values listed in the examples can be combined arbitrarily to constitute a numerical range. Further, numerical values arbitrarily selected from within the numerical value range can be used as upper limit and lower limit numerical values.
　本発明の負極活物質は、Ａｌ質量％（ＷＡｌ％）が０＜ＷＡｌ＜１を満足し、Ｓｉ質量％（ＷＳｉ％）が６０≦ＷＳｉ≦９０を満足するＡｌ含有シリコン材料（以下、本発明のＡｌ含有シリコン材料ということがある。）を含むことを特徴とする。 In the negative electrode active material of the present invention, an Al-containing silicon material (Al mass% (W Al %) satisfies 0 <W Al <1 and Si mass% (W Si %) satisfies 60 ≦ W Si ≦ 90 ( Hereinafter, the present invention is characterized by including the Al-containing silicon material of the present invention.
　本発明のＡｌ含有シリコン材料は、Ａｌの存在に因り、導電性が向上するため、低抵抗な二次電池用の負極活物質として有用であるといえる。ただし、シリコン材料を具備する負極にて電荷担体の授受を行うのは、シリコンであるので、Ａｌ質量％が高すぎるシリコン材料は、負極活物質として好ましいとはいえない。 The Al-containing silicon material of the present invention can be said to be useful as a negative electrode active material for a low resistance secondary battery because the conductivity is improved due to the presence of Al. However, since it is silicon that performs charge carrier transfer with the negative electrode comprising a silicon material, a silicon material having too high an Al mass% is not preferable as a negative electrode active material.
　本発明のＡｌ含有シリコン材料においては、ＷＡｌ％が０＜ＷＡｌ≦０．８を満足するのが好ましく、０．０１≦ＷＡｌ≦０．８を満足するのが好ましく、０．０５≦ＷＡｌ≦０．６を満足するのがより好ましく、０．１≦ＷＡｌ≦０．５を満足するのがさらに好ましく、０．１５≦ＷＡｌ≦０．５を満足するのが特に好ましい。 In the Al-containing silicon material of the present invention, W Al % preferably satisfies 0 <W Al ≦ 0.8, preferably 0.01 ≦ W Al ≦ 0.8, and 0.05 ≦ It is more preferable to satisfy W Al ≦ 0.6, it is further preferable to satisfy 0.1 ≦ W Al ≦ 0.5, and it is particularly preferable to satisfy 0.15 ≦ W Al ≦ 0.5.
　また、二次電池の充放電条件下においては、電解液の構成成分が分解して、負極活物質の表面に酸素を含むＳＥＩ（Ｓｏｌｉｄ　Ｅｌｅｃｔｒｏｌｙｔｅ　Ｉｎｔｅｒｐｈａｓｅ）被膜が形成することが知られている。ここで、負極活物質がシリコンを含有するシリコン材料の場合、シリコン材料のシリコンがＳＥＩ被膜に含まれる酸素によって酸化されて劣化することが懸念される。
　しかしながら、本発明のＡｌ含有シリコン材料は、Ａｌを含有するので、シリコンの酸化劣化が抑制されると考えられる。その理由は、Ａｌはシリコンよりも電気陰性度が低いため酸素と優先的にかつ安定に結合すると考えられる点、Ａｌと酸素とのＡｌ－Ｏ結合がＳｉ－Ｏ結合よりも安定である点、及び、安定なＡｌ－Ｏ結合を形成した酸素はＡｌよりも電気陰性度の高いシリコンの酸化には関与し難いといえる点にある。
　したがって、本発明のＡｌ含有シリコン材料を負極活物質として具備する二次電池は、長寿命であることが期待できる。 Further, it is known that, under charge and discharge conditions of a secondary battery, constituents of the electrolytic solution are decomposed to form an SEI (Solid Electrolyte Interphase) film containing oxygen on the surface of the negative electrode active material. Here, in the case where the negative electrode active material is a silicon material containing silicon, there is a concern that the silicon of the silicon material is oxidized by oxygen contained in the SEI film to be degraded.
However, since the Al-containing silicon material of the present invention contains Al, it is considered that the oxidative deterioration of silicon is suppressed. The reason is that Al is considered to bind preferentially and stably to oxygen since it has lower electronegativity than silicon, and that Al-O bond of Al and oxygen is more stable than Si-O bond. Also, oxygen having a stable Al—O bond can be said to be less likely to be involved in the oxidation of silicon which is more electronegative than Al.
Therefore, a secondary battery including the Al-containing silicon material of the present invention as a negative electrode active material can be expected to have a long life.
　本明細書において、シリコン材料とは、シリコンを主な構成成分とする材料を意味する。本発明のＡｌ含有シリコン材料におけるＳｉ質量％（ＷＳｉ％）は、７０≦ＷＳｉ≦８５を満足するのが好ましく、８０≦ＷＳｉ≦８５を満足するのがより好ましい。
　Ｓｉ質量％が低すぎると、本発明のＡｌ含有シリコン材料の単位質量あたりの容量が低くなるため、負極活物質としての能力が不十分となる場合がある。Ｓｉ質量％が高すぎると、充放電時の本発明のＡｌ含有シリコン材料の膨張及び収縮の程度が大きくなりすぎて、本発明のＡｌ含有シリコン材料が破損する懸念がある。 In the present specification, a silicon material means a material containing silicon as a main component. The Si mass% (W Si %) in the Al-containing silicon material of the present invention preferably satisfies 70 ≦ W Si ≦ 85, and more preferably 80 ≦ W Si ≦ 85.
If the Si mass% is too low, the capacity per unit mass of the Al-containing silicon material of the present invention will be low, so the capacity as a negative electrode active material may be insufficient. If the Si mass% is too high, the degree of expansion and contraction of the Al-containing silicon material of the present invention during charge and discharge becomes too large, and there is a concern that the Al-containing silicon material of the present invention may be broken.
　本発明のＡｌ含有シリコン材料には、本発明の趣旨を逸脱しない範囲内で、他の元素が存在してもよい。他の元素としては、原料や製造工程に由来するものが挙げられる。他の元素として具体的に、Ｆｅ、Ｏ、Ｃａ、Ｃ、ハロゲンを例示できる。 Other elements may be present in the Al-containing silicon material of the present invention without departing from the spirit of the present invention. Other elements include those derived from raw materials and production processes. Specific examples of other elements include Fe, O, Ca, C and halogen.
　本発明のＡｌ含有シリコン材料におけるＦｅ質量％（ＷＦｅ％）は、０≦ＷＦｅ≦３を満足するのが好ましく、０≦ＷＦｅ≦１を満足するのがより好ましく、０≦ＷＦｅ≦０．５を満足するのがさらに好ましく、０≦ＷＦｅ≦０．３を満足するのが特に好ましく、０≦ＷＦｅ≦０．１を満足するのが最も好ましい。Ｆｅの混入容易性及び除去困難性を鑑みると、本発明のＡｌ含有シリコン材料におけるＦｅ質量％（ＷＦｅ％）は、０＜ＷＦｅとなる場合が想定される。
　また、Ａｌ質量％（ＷＡｌ％）とＦｅ質量％（ＷＦｅ％）の関係が、ＷＡｌ＞ＷＦｅを満足するのが好ましく、ＷＡｌ＞２×ＷＦｅを満足するのがより好ましい。 Fe wt% in Al-containing silicon material of the present invention (W Fe%) is preferably satisfies 0 ≦ W Fe ≦ 3, more preferably satisfies 0 ≦ W Fe ≦ 1, 0 ≦ W Fe ≦ It is more preferable to satisfy 0.5, particularly preferably to satisfy 0 ≦ W Fe ≦ 0.3, and most preferably to satisfy 0 ≦ W Fe ≦ 0.1. In view of easiness of mixing of Fe and difficulty of removal, it is assumed that Fe mass% (W 2 Fe %) in the Al-containing silicon material of the present invention is 0 <W 2 Fe .
Moreover, it is preferable that the relationship of Al mass% (W Al %) and Fe mass% (W Fe %) satisfies W Al > W Fe, and more preferably W Al > 2 × W Fe .
　本発明のＡｌ含有シリコン材料におけるＯ質量％（ＷＯ％）は、５≦ＷＯ≦３０を満足するのが好ましく、１０≦ＷＯ≦２５を満足するのがより好ましく、１２≦ＷＯ≦２２を満足するのがさらに好ましく、１３≦ＷＯ≦２１を満足するのが特に好ましい。
　本発明のＡｌ含有シリコン材料が一定程度の酸素を含有することで、本発明のＡｌ含有シリコン材料を負極活物質として具備する二次電池の寿命が長くなる。 O wt% in Al-containing silicon material of the present invention (W O%) is preferably satisfies 5 ≦ W O ≦ 30, more preferably satisfies 10 ≦ W O ≦ 25, 12 ≦ W O ≦ It is further preferable to satisfy 22, and it is particularly preferable to satisfy 13 ≦ W o ≦ 21.
When the Al-containing silicon material of the present invention contains a certain degree of oxygen, the life of a secondary battery including the Al-containing silicon material of the present invention as a negative electrode active material is extended.
　本発明のＡｌ含有シリコン材料におけるＣａ質量％（ＷＣａ％）は、０≦ＷＣａ≦３を満足するのが好ましく、０≦ＷＣａ≦１を満足するのがより好ましく、０≦ＷＣａ≦０．５を満足するのがさらに好ましく、０≦ＷＣａ≦０．３を満足するのが特に好ましい。Ｃａの混入容易性及び除去困難性を鑑みると、本発明のＡｌ含有シリコン材料におけるＣａ質量％（ＷＣａ％）は、０＜ＷＣａとなる場合が想定される。 Ca mass% in Al-containing silicon material of the present invention (W Ca%) is preferably satisfies 0 ≦ W Ca ≦ 3, more preferably satisfies 0 ≦ W Ca ≦ 1, 0 ≦ W Ca ≦ It is further preferable to satisfy 0.5, and it is particularly preferable to satisfy 0 ≦ W Ca ≦ 0.3. In view of the ease of incorporation and removal of Ca , it is assumed that Ca mass% (W Ca %) in the Al-containing silicon material of the present invention is 0 <W Ca.
　本発明のＡｌ含有シリコン材料におけるハロゲン質量％（ＷＸ％）は、０≦ＷＸ≦３を満足するのが好ましく、０≦ＷＸ≦２を満足するのがより好ましく、０≦ＷＸ≦１を満足するのがさらに好ましく、０≦ＷＸ≦０．５を満足するのが特に好ましい。ハロゲンの混入容易性及び除去困難性を鑑みると、本発明のＡｌ含有シリコン材料におけるハロゲン質量％（ＷＸ％）は、０＜ＷＸとなる場合が想定される。 The halogen mass% (W x %) in the Al-containing silicon material of the present invention preferably satisfies 0 ≦ W x ≦ 3, more preferably 0 ≦ W x ≦ 2, and 0 ≦ W x ≦ It is more preferable to satisfy 1 and particularly preferable to satisfy 0 ≦ W x ≦ 0.5. In view of easiness of mixing and removal of halogen, it is assumed that the mass% (W x %) of halogen in the Al-containing silicon material of the present invention is 0 <W x .
　本発明のＡｌ含有シリコン材料を構造の面から述べると、複数枚の板状シリコン体が厚さ方向に積層されてなる構造を有するものが好ましい。本発明のＡｌ含有シリコン材料を二次電池の活物質として使用することを考慮すると、リチウムイオンなどの電荷担体の効率的な挿入及び脱離反応のためには、上記板状シリコン体は厚さが１０ｎｍ～１００ｎｍの範囲内のものが好ましく、２０ｎｍ～５０ｎｍの範囲内のものがより好ましい。また、板状シリコン体の長軸方向の長さは、０．１μｍ～５０μｍの範囲内のものが好ましい。また、板状シリコン体は、（長軸方向の長さ）／（厚さ）が２～１０００の範囲内であるのが好ましい。 When the Al-containing silicon material of the present invention is described in terms of structure, it is preferable to have a structure in which a plurality of plate-like silicon bodies are stacked in the thickness direction. In view of using the Al-containing silicon material of the present invention as an active material of a secondary battery, the plate-like silicon body has a thickness for efficient insertion and desorption reaction of charge carriers such as lithium ions. Is preferably in the range of 10 nm to 100 nm, and more preferably in the range of 20 nm to 50 nm. The length of the plate-like silicon body in the long axis direction is preferably in the range of 0.1 μm to 50 μm. The plate-like silicon body preferably has a (longitudinal direction length) / (thickness) in the range of 2 to 1,000.
　本発明のＡｌ含有シリコン材料は、アモルファスシリコンやシリコン結晶子を含有するものが好ましい。シリコン結晶子のサイズとしては、ナノサイズのものが好ましい。具体的には、シリコン結晶子サイズは、０．５ｎｍ～３００ｎｍの範囲内が好ましく、１ｎｍ～１００ｎｍの範囲内がより好ましく、１ｎｍ～５０ｎｍの範囲内がさらに好ましく、１ｎｍ～１０ｎｍの範囲内が特に好ましい。シリコン結晶子サイズは、本発明のＡｌ含有シリコン材料に対してＸ線回折測定（ＸＲＤ測定）を行い、得られたＸＲＤチャートのＳｉ（１１１）面の回折ピークの半値幅を用いたシェラーの式から算出される。 The Al-containing silicon material of the present invention preferably contains amorphous silicon or silicon crystallites. The size of the silicon crystallite is preferably nano-sized. Specifically, the silicon crystallite size is preferably in the range of 0.5 nm to 300 nm, more preferably in the range of 1 nm to 100 nm, still more preferably in the range of 1 nm to 50 nm, particularly preferably in the range of 1 nm to 10 nm preferable. For the silicon crystallite size, X-ray diffraction measurement (XRD measurement) is performed on the Al-containing silicon material of the present invention, and the Scheller equation using the half value width of the diffraction peak of the Si (111) plane of the obtained XRD chart Calculated from
　本発明のＡｌ含有シリコン材料は、粒子状のものが好ましい。本発明のＡｌ含有シリコン材料の平均粒子径としては、１～３０μｍの範囲内が好ましく、２～２０μｍの範囲内がより好ましく、３～１０μｍの範囲内がさらに好ましい。なお、明細書において、平均粒子径とは、一般的なレーザー回折式粒度分布測定装置で測定した場合における、Ｄ５０を意味する。 The Al-containing silicon material of the present invention is preferably in the form of particles. The average particle diameter of the Al-containing silicon material of the present invention is preferably in the range of 1 to 30 μm, more preferably in the range of 2 to 20 μm, and still more preferably in the range of 3 to 10 μm. Incidentally, in the specification, the average particle size, when measured in conventional laser diffraction particle size distribution measuring apparatus, means D 50.
　次に、本発明のＡｌ含有シリコン材料を含む負極活物質の製造方法の一態様を説明する。
　本発明のＡｌ含有シリコン材料を含む負極活物質の製造方法の一態様は、
　ａ）Ｃａ、Ａｌ及びＳｉを含む溶湯を冷却して、固体とする工程、
　ｂ）前記固体を酸と反応させて、Ａｌ含有シリコン材料の前駆体を得る工程、
　ｃ）前記前駆体を３００℃以上で加熱する工程、
　を含むことを特徴とする。 Next, an aspect of a method of manufacturing a negative electrode active material containing the Al-containing silicon material of the present invention will be described.
One aspect of a method of producing a negative electrode active material containing the Al-containing silicon material of the present invention is
a) cooling the molten metal containing Ca, Al and Si to solidify it;
b) reacting the solid with an acid to obtain a precursor of an Al-containing silicon material,
c) heating the precursor at 300 ° C. or higher,
It is characterized by including.
　上記製造方法は、本発明のＡｌ含有シリコン材料として、複数枚の板状シリコン体が厚さ方向に積層されてなる構造を有するものを製造するのに好適である。上記製造方法のａ）工程、ｂ）工程及びｃ）工程における、化学変化の一例を、Ａｌを無視して、理想的な反応式で示すと、以下のとおりとなる。
　ａ）工程：Ｃａ＋２Ｓｉ→ＣａＳｉ２
　ｂ）工程：３ＣａＳｉ２＋６ＨＣｌ→Ｓｉ６Ｈ６＋３ＣａＣｌ２
　ｃ）工程：Ｓｉ６Ｈ６→６Ｓｉ＋３Ｈ２↑ The above manufacturing method is suitable for manufacturing the Al-containing silicon material of the present invention having a structure in which a plurality of plate-like silicon bodies are stacked in the thickness direction. An example of the chemical change in the steps a), b) and c) of the above-mentioned production method is as follows, which is represented by an ideal reaction equation ignoring Al.
a) Process: Ca + 2 Si → Ca Si 2
b) Process: 3CaSi 2 + 6HCl → Si 6 H 6 + 3CaCl 2
c) Process: Si 6 H 6 → 6 Si + 3 H 2 ↑
　複数枚の板状シリコン体が厚さ方向に積層されてなる構造を有する本発明のＡｌ含有シリコン材料の積層構造は、ＣａＳｉ２やＳｉ６Ｈ６におけるＳｉ層に由来すると考えられる。 The laminated structure of the Al-containing silicon material of the present invention having a structure in which a plurality of plate-like silicon bodies are laminated in the thickness direction is considered to be derived from the Si layer in CaSi 2 or Si 6 H 6 .
　ａ）工程について説明する。ａ）工程で用いられるＣａ、Ａｌ及びＳｉとしては、元素単体又はこれら元素の合金が好ましい。ＣａＳｉ２を原料の一部として用いてもよい。溶湯におけるＣａ及びＳｉの元素組成比は、１：１．５～１：２．５の範囲内が好ましく、１：１．８～１：２．２の範囲内がより好ましく、１：１．９～１：２．１の範囲内がさらに好ましい。 a) The process will be described. As Ca, Al and Si used at a process a), an element single-piece | unit or the alloy of these elements is preferable. CaSi 2 may be used as part of the raw material. The elemental composition ratio of Ca and Si in the molten metal is preferably in the range of 1: 1.5 to 1: 2.5, more preferably in the range of 1: 1.8 to 1: 2.2, and 1: 1. The range of 9 to 1: 2.1 is more preferable.
　溶湯におけるＡｌの量としては、製造しようとする本発明のＡｌ含有シリコン材料におけるＡｌ質量比に応じて適宜決定すればよい。ただし、Ａｌは酸に溶解し得るため、次工程のｂ）工程において、前駆体中のＡｌ量が減少する場合がある。そのため、溶湯には、やや多めのＡｌを添加しておくことが好ましい。 The amount of Al in the molten metal may be appropriately determined according to the Al mass ratio in the Al-containing silicon material of the present invention to be produced. However, since Al can be dissolved in an acid, the amount of Al in the precursor may be reduced in step b) of the next step. Therefore, it is preferable to add a little more Al to the molten metal.
　本発明者は、ａ）工程にて、ＡｌがＣａＳｉ２のＳｉと置換してなる置換型固溶体ＣａＳｉ２－ｘＡｌｘが製造されると考えた。そこで、当該固溶体の状態図を、熱力学平衡計算ソフト（ＦａｃｔＳａｇｅ、株式会社計算力学研究センター）を用いて算出した。図１に状態図を示す。 The present inventors have considered that in step a), Al is substituted solid solution CaSi 2-x Al x obtained by replacing the Si of CaSi 2 is manufactured. Therefore, the phase diagram of the solid solution was calculated using thermodynamic equilibrium calculation software (FactSage, Computational Mechanics Research Center, Inc.). A state diagram is shown in FIG.
　図１の状態図からみて、ｘは、０＜ｘ＜０．１６の範囲内である。ｘ＝０．１６の場合の置換型固溶体の組成式は、ＣａＳｉ２－０．１６Ａｌ０．１６となる。当該置換型固溶体に対するＡｌの質量％は、１００×２６．９８×０．１６／（４０．０８＋２８．０９×１．８４＋２６．９８×０．１６）＝４．５と計算される。ただし、図１の状態図からみて、常温での置換型固溶体の組成式におけるＡｌの量は著しく低い。
　よって、溶湯における、Ｃａ、Ｓｉ及びＡｌの合計質量に対するＡｌの質量％は、４．５％未満が好ましく、０．０１～３％の範囲内がより好ましく、０．０５～２％の範囲内がさらに好ましく、０．１～１％の範囲内が特により好ましいと考えられる。なお、過剰にＡｌを添加すると、ＣａＡｌ２Ｓｉ２も生成すると考えられるが、ＣａＡｌ２Ｓｉ２は次工程のｂ）工程において分解して消失する。 As seen from the state diagram of FIG. 1, x is in the range of 0 <x <0.16. The composition formula of the substitutional solid solution in the case of x = 0.16 is CaSi 2 -0.16 Al 0.16 . The mass% of Al relative to the substitutional solid solution is calculated to be 100 × 26.98 × 0.16 / (40.08 + 28.09 × 1.84 + 26.98 × 0.16) = 4.5. However, in view of the phase diagram of FIG. 1, the amount of Al in the composition formula of the substitutional solid solution at ordinary temperature is extremely low.
Therefore, less than 4.5% of the mass% of Al based on the total mass of Ca, Si and Al in the molten metal is preferably within the range of 0.01 to 3%, and more preferably within the range of 0.05 to 2%. Is more preferably in the range of 0.1 to 1%. Incidentally, an excessive addition of Al, it is considered that CaAl 2 Si 2 also generates, CaAl 2 Si 2 disappears by decomposition in the next step of b) step.
　ａ）工程の溶湯温度としては、Ｃａ、Ａｌ及びＳｉの混合物が溶湯となり得る温度であればよい。ここで、溶湯とは、Ｃａ、Ａｌ及びＳｉの混合物の液体様の状態を意味する。溶湯温度としては１０５０℃～１８００℃の範囲内が好ましく、１１００℃～１５００℃の範囲内がより好ましく、１２００℃～１４００℃の範囲内がさらに好ましい。 The molten metal temperature in the step a) may be a temperature at which a mixture of Ca, Al and Si can be a molten metal. Here, the molten metal means a liquid-like state of a mixture of Ca, Al and Si. The temperature of the molten metal is preferably in the range of 1050 ° C. to 1800 ° C., more preferably in the range of 1100 ° C. to 1500 ° C., and still more preferably in the range of 1200 ° C. to 1400 ° C.
　ａ）工程で用いる加熱装置としては、例えば、高周波誘導加熱装置、電気炉、ガス炉を使用することができる。ａ）工程は、加圧又は減圧条件下としてもよいし、アルゴン、ヘリウム、窒素などの不活性ガス雰囲気下としてもよい。 As a heating device used at a) process, a high frequency induction heating device, an electric furnace, and a gas furnace can be used, for example. The step a) may be performed under pressure or reduced pressure conditions, or under an inert gas atmosphere such as argon, helium or nitrogen.
　溶湯の冷却は、できるだけ早い速度で温度を低下させるのが好ましい。置換型固溶体の生成と共に、侵入型固溶体の生成も期待できるためである。溶湯を冷却する方法としては、所定の型に溶湯を注いで室温で放置する方法でもよいが、急速冷却装置を用いた冷却方法でもよい。 It is preferable to cool the melt at a rate as fast as possible. Along with the formation of the substitutional solid solution, the formation of the interstitial solid solution can also be expected. As a method of cooling the molten metal, the molten metal may be poured into a predetermined mold and left at room temperature, but a cooling method using a rapid cooling device may be used.
　本明細書で述べる急速冷却装置とは、溶湯を放置して冷却する装置は含まれず、溶湯を強制的に冷却する装置を意味する。急速冷却装置としては、回転する冷却ロール上に溶湯を噴射する冷却手段（いわゆるメルトスパン法、ストリップキャスト法、又は、メルトスピニング法）や、細流化した溶湯に対して流体を吹き付けるアトマイズ法などの冷却手段を用いた冷却装置を例示できる。アトマイズ法としては、ガスアトマイズ法、水アトマイズ法、遠心力アトマイズ法、プラズマアトマイズ法を例示できる。具体的な急速冷却装置としては、液体急冷凝固装置、急冷薄片製造装置、液中紡糸装置、ガスアトマイズ装置、水アトマイズ装置、回転ディスク装置、回転電極法装置（以上、日新技研株式会社）、液体急冷装置、ガスアトマイズ装置（以上、株式会社真壁技研）を例示できる。好ましい冷却速度として、１０００～１０００００℃／秒を例示できる。 The rapid cooling device described in the present specification does not include a device for leaving and cooling the molten metal, but means a device for forcibly cooling the molten metal. As a rapid cooling device, a cooling means (so-called melt span method, strip casting method, or melt spinning method) for injecting a molten metal onto a rotating cooling roll, or a cooling method such as an atomizing method for spraying a fluid onto a molten metal The cooling device using the means can be illustrated. As the atomizing method, a gas atomizing method, a water atomizing method, a centrifugal atomizing method, and a plasma atomizing method can be exemplified. Specific rapid cooling devices include liquid rapid solidification devices, rapid cooling thin plate production devices, in-liquid spinning devices, gas atomizing devices, water atomizing devices, rotating disk devices, rotating electrode method devices (Nisshin Giken Co., Ltd.), liquid A quenching apparatus and a gas atomizing apparatus (above, Makabe Giken Co., Ltd.) can be exemplified. As a preferable cooling rate, 1000 to 100,000 ° C./second can be exemplified.
　また、冷却して得られた固体の固体状態を維持しつつ加熱する、アニール工程を追加してもよい。図１の状態図から、９００℃付近において、置換型固溶体ＣａＳｉ２－ｘＡｌｘが最も生成しやすいと考えられる。そのため、アニール工程の加熱温度としては、８００～１０００℃が好ましく、８５０～９５０℃がより好ましい。加熱時間としては、１～５０時間、５～３０時間を例示できる。アニール工程後には、当然に、固体を冷却する。 In addition, an annealing step may be added in which heating is performed while maintaining the solid state obtained by cooling. From the phase diagram of FIG. 1, it is considered that the substitutional solid solution CaSi 2 -xAl x is most likely to be formed at around 900 ° C. Therefore, the heating temperature in the annealing step is preferably 800 to 1000 ° C., and more preferably 850 to 950 ° C. The heating time may be, for example, 1 to 50 hours or 5 to 30 hours. Naturally, the solid is cooled after the annealing step.
　冷却して得られた固体を粉砕してもよく、さらに分級してもよい。 The solid obtained by cooling may be crushed or further classified.
　次に、ｂ）工程について説明する。ｂ）工程は、ａ）工程で得られた固体を酸と反応させて、Ａｌ含有シリコン材料の前駆体を得る工程である。Ａｌ含有シリコン材料の前駆体は、ＣａＳｉ２－ｘＡｌｘやＣａＳｉ２によるＳｉ層の基本骨格が維持されているため、層状をなす。 Next, the step b) will be described. Step b) is a step of reacting the solid obtained in step a) with an acid to obtain a precursor of an Al-containing silicon material. Precursor of Al-containing silicon material, because the basic skeleton of Si layer by CaSi 2-x Al x or CaSi 2 is maintained, forms a lamellar.
　酸としては、フッ化水素酸、塩化水素酸、臭化水素酸、ヨウ化水素酸、硫酸、硝酸、リン酸、蟻酸、酢酸、メタンスルホン酸、テトラフルオロホウ酸、ヘキサフルオロリン酸、ヘキサフルオロヒ素酸、フルオロアンチモン酸、ヘキサフルオロケイ酸、ヘキサフルオロゲルマン酸、ヘキサフルオロスズ（ＩＶ）酸、トリフルオロ酢酸、ヘキサフルオロチタン酸、ヘキサフルオロジルコニウム酸、トリフルオロメタンスルホン酸、フルオロスルホン酸が例示される。これらの酸を単独又は併用して使用すれば良い。 As the acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, methanesulfonic acid, tetrafluoroboric acid, hexafluorophosphoric acid, hexafluoro acid Arsenic acid, fluoroantimonic acid, hexafluorosilicic acid, hexafluorogermanic acid, hexafluorotin (IV) acid, trifluoroacetic acid, hexafluorotitanic acid, hexafluorozirconic acid, trifluoromethanesulfonic acid, fluorosulfonic acid are exemplified. Ru. These acids may be used alone or in combination.
　ｂ）工程において、酸は、モル比にて、ａ）工程で得られた固体に含まれるＣａよりも過剰に用いるのが好ましい。同工程は無溶媒で行ってもよいが、目的物の分離やＣａＣｌ２などの副生物の除去の観点から溶媒として水を採用するのが好ましい。同工程の反応条件は、真空などの減圧条件又は不活性ガス雰囲気下とすることが好ましく、また、氷浴などの室温以下の温度条件とするのが好ましい。同工程の反応時間は適宜設定すれば良い。 In the step b), the acid is preferably used in molar ratio in excess of Ca contained in the solid obtained in the step a). Although the process may be carried out without a solvent, it is preferable to use water as a solvent from the viewpoint of separation of the target substance and removal of byproducts such as CaCl 2 and the like. The reaction conditions in the same step are preferably reduced pressure conditions such as vacuum or under an inert gas atmosphere, and it is preferable to set temperature conditions below room temperature such as an ice bath. The reaction time of the same process may be set appropriately.
　ｂ）工程は、水存在下で行われるのが好ましく、そしてＳｉ６Ｈ６は水と反応し得る。そのため、ｂ）工程においては、例えば、以下の反応も進行すると考えられる。
　Ｓｉ６Ｈ６＋３Ｈ２Ｏ→Ｓｉ６Ｈ３(ＯＨ)３＋３Ｈ２↑
　したがって、Ａｌ含有シリコン材料の前駆体には、酸素が含まれ得る。また、使用した酸のアニオン由来の元素も含まれ得る。 The step b) is preferably carried out in the presence of water, and Si 6 H 6 can be reacted with water. Therefore, in the step b), for example, the following reaction is considered to proceed.
Si 6 H 6 + 3H 2 O → Si 6 H 3 (OH) 3 + 3H 2 ↑
Thus, the precursor of the Al-containing silicon material may contain oxygen. Moreover, the element derived from the anion of the used acid may also be included.
　次に、ｃ）工程について説明する。ｃ）工程は、Ａｌ含有シリコン材料の前駆体を３００℃以上で加熱し、水素や水などを離脱させ、Ａｌ含有シリコン材料を得る工程である。 Next, the step c) will be described. The step c) is a step of heating the precursor of the Al-containing silicon material at 300 ° C. or higher to release hydrogen, water and the like to obtain the Al-containing silicon material.
　ｃ）工程は、通常の大気下よりも酸素含有量の少ない非酸化性雰囲気下で行われるのが好ましい。非酸化性雰囲気としては、真空を含む減圧雰囲気、不活性ガス雰囲気を例示できる。加熱温度は、３５０℃～９５０℃の範囲内が好ましく、４００℃～９００℃の範囲内がより好ましい。加熱温度が低すぎると水素の離脱が十分でない場合があり、また、加熱温度が高すぎるとエネルギーの無駄になる。加熱時間は加熱温度に応じて適宜設定すれば良い。反応系外に抜けていく水素などの量を測定しながら加熱時間を決定するのが好ましい。加熱温度及び加熱時間を適宜選択することにより、製造されるＡｌ含有シリコン材料に含まれるアモルファスシリコン及びシリコン結晶子の割合、並びに、シリコン結晶子の大きさを調製することもできる。加熱温度及び加熱時間を適宜選択することにより、製造されるＡｌ含有シリコン材料に含まれるアモルファスシリコン及びシリコン結晶子を含むナノ水準の厚みの層の形状を調製することもできる。 The step c) is preferably carried out in a non-oxidizing atmosphere having a lower oxygen content than under normal atmosphere. As the non-oxidizing atmosphere, a reduced pressure atmosphere including vacuum and an inert gas atmosphere can be exemplified. The heating temperature is preferably in the range of 350 ° C. to 950 ° C., and more preferably in the range of 400 ° C. to 900 ° C. If the heating temperature is too low, hydrogen may not be sufficiently released, and if the heating temperature is too high, energy is wasted. The heating time may be set appropriately according to the heating temperature. It is preferable to determine the heating time while measuring the amount of hydrogen and the like that escapes from the reaction system. By appropriately selecting the heating temperature and the heating time, the ratio of amorphous silicon and silicon crystallite contained in the Al-containing silicon material to be produced and the size of silicon crystallite can also be adjusted. By appropriately selecting the heating temperature and the heating time, it is also possible to prepare the shape of a nano-level thick layer including amorphous silicon and silicon crystallite contained in the Al-containing silicon material to be produced.
　得られたＡｌ含有シリコン材料を粉砕してもよく、さらに分級してもよい。 The obtained Al-containing silicon material may be crushed or further classified.
　本発明のＡｌ含有シリコン材料は、リチウムイオン二次電池などの二次電池、電気二重層コンデンサ及びリチウムイオンキャパシタなどの蓄電装置の負極活物質として使用することができる。また、本発明のＡｌ含有シリコン材料は、例えばＣＭＯＳ、半導体メモリ及び太陽電池などの材料や、光触媒材料などとしても利用することができる。 The Al-containing silicon material of the present invention can be used as a negative electrode active material of a storage battery such as a secondary battery such as a lithium ion secondary battery, an electric double layer capacitor, and a lithium ion capacitor. The Al-containing silicon material of the present invention can also be used as, for example, a material such as a CMOS, a semiconductor memory, and a solar cell, or as a photocatalytic material.
　以下、蓄電装置の代表例として、本発明のＡｌ含有シリコン材料を負極活物質として具備する本発明のリチウムイオン二次電池について説明する。具体的には、本発明のリチウムイオン二次電池は、正極、本発明のＡｌ含有シリコン材料を負極活物質として具備する負極、電解液及びセパレータを具備する。 Hereinafter, the lithium ion secondary battery of the present invention including the Al-containing silicon material of the present invention as a negative electrode active material will be described as a representative example of the power storage device. Specifically, the lithium ion secondary battery of the present invention includes a positive electrode, a negative electrode including the Al-containing silicon material of the present invention as a negative electrode active material, an electrolytic solution, and a separator.
　正極は、集電体と、集電体の表面に結着させた正極活物質層を有する。 The positive electrode has a current collector and a positive electrode active material layer bonded to the surface of the current collector.
　集電体は、リチウムイオン二次電池の放電又は充電の間、電極に電流を流し続けるための化学的に不活性な電子伝導体をいう。集電体としては、銀、銅、金、アルミニウム、タングステン、コバルト、亜鉛、ニッケル、鉄、白金、錫、インジウム、チタン、ルテニウム、タンタル、クロム、モリブデンから選ばれる少なくとも一種、並びにステンレス鋼などの金属材料を例示することができる。集電体は公知の保護層で被覆されていても良い。集電体の表面を公知の方法で処理したものを集電体として用いても良い。 The current collector refers to a chemically inert electron conductor for keeping current flowing to the electrode during discharge or charge of the lithium ion secondary battery. As the current collector, at least one selected from silver, copper, gold, aluminum, tungsten, cobalt, zinc, nickel, iron, platinum, tin, indium, titanium, ruthenium, tantalum, chromium, molybdenum, stainless steel, etc. A metal material can be illustrated. The current collector may be coated with a known protective layer. What processed the surface of a collector by a well-known method may be used as a collector.
　集電体は箔、シート、フィルム、線状、棒状、メッシュなどの形態をとることができる。そのため、集電体として、例えば、銅箔、ニッケル箔、アルミニウム箔、ステンレス箔などの金属箔を好適に用いることができる。集電体が箔、シート、フィルム形態の場合は、その厚みが１μｍ～１００μｍの範囲内であることが好ましい。 The current collector can take the form of a foil, a sheet, a film, a line, a rod, a mesh or the like. Therefore, as the current collector, for example, metal foils such as copper foil, nickel foil, aluminum foil, and stainless steel foil can be suitably used. When the current collector is in the form of a foil, a sheet or a film, the thickness is preferably in the range of 1 μm to 100 μm.
　正極活物質層は正極活物質、並びに必要に応じて導電助剤及び／又は結着剤を含む。 The positive electrode active material layer contains a positive electrode active material and, if necessary, a conductive aid and / or a binder.
　正極活物質としては、層状化合物のＬｉａＮｉｂＣｏｃＭｎｄＤｅＯｆ(０．２≦ａ≦２、ｂ＋ｃ＋ｄ＋ｅ＝１、０≦ｅ＜１、ＤはＬｉ、Ｆｅ、Ｃｒ、Ｃｕ、Ｚｎ、Ｃａ、Ｍｇ、Ｓ、Ｓｉ、Ｎａ、Ｋ、Ａｌ、Ｚｒ、Ｔｉ、Ｐ、Ｇａ、Ｇｅ、Ｖ、Ｍｏ、Ｎｂ、Ｗ、Ｌａから選ばれる少なくとも１の元素、１．７≦ｆ≦３)、ＬｉａＮｉｂＣｏｃＡｌｄＤｅＯｆ(０．２≦ａ≦２、ｂ＋ｃ＋ｄ＋ｅ＝１、０≦ｅ＜１、ＤはＬｉ、Ｆｅ、Ｃｒ、Ｃｕ、Ｚｎ、Ｃａ、Ｍｇ、Ｓ、Ｓｉ、Ｎａ、Ｋ、Ｚｒ、Ｔｉ、Ｐ、Ｇａ、Ｇｅ、Ｖ、Ｍｏ、Ｎｂ、Ｗ、Ｌａから選ばれる少なくとも１の元素、１．７≦ｆ≦３)、Ｌｉ２ＭｎＯ３を挙げることができる。また、正極活物質として、ＬｉＭｎ２Ｏ４等のスピネル、及びスピネルと層状化合物の混合物で構成される固溶体、ＬｉＭＰＯ４、ＬｉＭＶＯ４又はＬｉ２ＭＳｉＯ４（式中のＭはＣｏ、Ｎｉ、Ｍｎ、Ｆｅのうちの少なくとも一種から選択される）などで表されるポリアニオン系化合物を挙げることができる。さらに、正極活物質として、ＬｉＦｅＰＯ４ＦなどのＬｉＭＰＯ４Ｆ（Ｍは遷移金属）で表されるタボライト系化合物、ＬｉＦｅＢＯ３などのＬｉＭＢＯ３（Ｍは遷移金属）で表されるボレート系化合物を挙げることができる。正極活物質として用いられるいずれの金属酸化物も上記の各組成式を基本組成とすればよく、基本組成に含まれる金属元素を他の金属元素で置換したものも正極活物質として使用可能である。また、正極活物質として、充放電に寄与するリチウムイオンを含まない正極活物質材料、たとえば、硫黄単体、硫黄と炭素を複合化した化合物、ＴｉＳ２などの金属硫化物、Ｖ２Ｏ５、ＭｎＯ２などの酸化物、ポリアニリン及びアントラキノン並びにこれら芳香族を化学構造に含む化合物、共役二酢酸系有機物などの共役系材料、その他公知の材料を用いることもできる。さらに、ニトロキシド、ニトロニルニトロキシド、ガルビノキシル、フェノキシルなどの安定なラジカルを有する化合物を正極活物質として採用してもよい。リチウムを含まない正極活物質材料を用いる場合には、正極および／または負極に、公知の方法により、予めイオンを添加させておく必要がある。ここで、当該イオンを添加するためには、金属または当該イオンを含む化合物を用いればよい。 As the positive electrode active material, a layered compound Li a Ni b Co c Mn d D e O f (0.2 ≦ a ≦ 2, b + c + d + e = 1,0 ≦ e <1, D is Li, Fe, Cr, Cu, At least one element selected from Zn, Ca, Mg, S, Si, Na, K, Al, Zr, Ti, P, Ga, V, Mo, Nb, W, La, 1.7 ≦ f ≦ 3 ), Li a Ni b Co c Al d DeO f (0.2 ≦ a ≦ 2, b + c + d + e = 1, 0 ≦ e <1, D is Li, Fe, Cr, Cu, Zn, Ca, Mg, S , At least one element selected from Si, Na, K, Zr, Ti, P, Ga, Ge, V, Mo, Nb, W, La, 1.7 ≦ f ≦ 3), Li 2 MnO 3 Can. In addition, as a positive electrode active material, spinel such as LiMn 2 O 4 and a solid solution composed of a mixture of spinel and layered compound, LiMPO 4 , LiMVO 4 or Li 2 MSiO 4 (M in the formula is Co, Ni, Mn, Polyanionic compounds represented by (at least one of Fe) and the like can be mentioned. Furthermore, as the positive electrode active material, tavorite compound (the M a transition metal) LiMPO 4 F, such as LiFePO 4 F represented by, Limbo 3 such LiFeBO 3 (M is a transition metal) include borate-based compound represented by be able to. Any metal oxide used as a positive electrode active material may have the above composition formula as a basic composition, and one obtained by substituting a metal element contained in the basic composition with another metal element can also be used as a positive electrode active material . In addition, as a positive electrode active material, a positive electrode active material containing no lithium ion contributing to charge and discharge, for example, a simple substance of sulfur, a compound of sulfur and carbon, a metal sulfide such as TiS 2 , V 2 O 5 , MnO Oxides such as 2 , polyaniline and anthraquinone, and compounds containing these aromatics in the chemical structure, conjugated materials such as conjugated diacetic acid organic substances, and other known materials can also be used. Furthermore, a compound having a stable radical such as nitroxide, nitronyl nitroxide, galvinoxyl, phenoxyl or the like may be adopted as the positive electrode active material. In the case of using a positive electrode active material containing no lithium, it is necessary to add ions to the positive electrode and / or the negative electrode by a known method. Here, in order to add the ions, a metal or a compound containing the ions may be used.
　導電助剤は、電極の導電性を高めるために添加される。そのため、導電助剤は、電極の導電性が不足する場合に任意に加えればよく、電極の導電性が十分に優れている場合には加えなくても良い。導電助剤としては化学的に不活性な電子高伝導体であれば良く、炭素質微粒子であるカーボンブラック、黒鉛、アセチレンブラック、ケッチェンブラック（登録商標）、気相法炭素繊維（Vapor Grown Carbon Fiber）、および各種金属粒子などが例示される。これらの導電助剤を単独または二種以上組み合わせて活物質層に添加することができる。 A conductive aid is added to enhance the conductivity of the electrode. Therefore, the conductive additive may be optionally added when the conductivity of the electrode is insufficient, and may not be added when the conductivity of the electrode is sufficiently excellent. The conductive auxiliary agent may be any chemically active high electron conductor, and carbon black particles such as carbon black, graphite, acetylene black, ketjen black (registered trademark), vapor grown carbon fiber (vapor grown carbon) Fiber), and various metal particles are exemplified. These conductive assistants can be added to the active material layer singly or in combination of two or more.
　活物質層中の導電助剤の配合割合は、質量比で、活物質：導電助剤＝１：０．００５～１：０．５であるのが好ましく、１：０．０１～１：０．２であるのがより好ましく、１：０．０３～１：０．１であるのがさらに好ましい。導電助剤が少なすぎると効率のよい導電パスを形成できず、また、導電助剤が多すぎると活物質層の成形性が悪くなるとともに電極のエネルギー密度が低くなるためである。 The compounding ratio of the conductive aid in the active material layer is, in mass ratio, preferably active material: conductive aid = 1: 0.005 to 1: 0.5, 1: 0.01 to 1: 0 It is more preferably 0.2, and more preferably 1: 0.03 to 1: 0.1. If the amount of the conductive additive is too small, efficient conductive paths can not be formed. If the amount of the conductive additive is too large, the formability of the active material layer deteriorates and the energy density of the electrode decreases.
　結着剤は、活物質や導電助剤を集電体の表面に繋ぎ止め、電極中の導電ネットワークを維持する役割を果たすものである。結着剤としては、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、フッ素ゴム等の含フッ素樹脂、ポリプロピレン、ポリエチレン等の熱可塑性樹脂、ポリイミド、ポリアミドイミド等のイミド系樹脂、アルコキシシリル基含有樹脂、ポリ（メタ）アクリル酸等のアクリル系樹脂、スチレン－ブタジエンゴム（ＳＢＲ）、カルボキシメチルセルロース、アルギン酸ナトリウム、アルギン酸アンモニウム等のアルギン酸塩、水溶性セルロースエステル架橋体、デンプン－アクリル酸グラフト重合体を例示することができる。これらの結着剤を単独で又は複数で採用すれば良い。 The binder plays the role of anchoring the active material and the conductive aid to the surface of the current collector and maintaining the conductive network in the electrode. The binder may, for example, be a fluorine-containing resin such as polyvinylidene fluoride, polytetrafluoroethylene or fluororubber, a thermoplastic resin such as polypropylene or polyethylene, an imide resin such as polyimide or polyamideimide, an alkoxysilyl group-containing resin, Examples of acrylic resins such as acrylic acid, styrene-butadiene rubber (SBR), alginates such as carboxymethylcellulose, sodium alginate and ammonium alginate, water-soluble cellulose ester cross-linked product, starch-acrylic acid graft polymer it can. These binders may be used alone or in combination.
　また、国際公開第２０１６／０６３８８２号に開示される、ポリアクリル酸やポリメタクリル酸などのカルボキシル基含有ポリマーをジアミンなどのポリアミンで架橋した架橋ポリマーを、結着剤として用いてもよい。 In addition, a crosslinked polymer in which a carboxyl group-containing polymer such as polyacrylic acid or polymethacrylic acid as disclosed in WO 2016/063882 is crosslinked with a polyamine such as diamine may be used as a binder.
　架橋ポリマーに用いられるジアミンとしては、エチレンジアミン、プロピレンジアミン、ヘキサメチレンジアミン等のアルキレンジアミン、１，４－ジアミノシクロヘキサン、１，３－ジアミノシクロヘキサン、イソホロンジアミン、ビス（４－アミノシクロヘキシル）メタン等の含飽和炭素環ジアミン、ｍ－フェニレンジアミン、ｐ－フェニレンジアミン、４，４’－ジアミノジフェニルメタン、４，４’－ジアミノジフェニルエーテル、ビス（４－アミノフェニル）スルホン、ベンジジン、ｏ－トリジン、２，４－トリレンジアミン、２，６－トリレンジアミン、キシリレンジアミン、ナフタレンジアミン等の芳香族ジアミンが挙げられる。 Examples of the diamine used for the cross-linked polymer include alkylene diamines such as ethylene diamine, propylene diamine and hexamethylene diamine, 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, isophorone diamine, bis (4-aminocyclohexyl) methane and the like. Saturated carbocyclic ring diamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylether, bis (4-aminophenyl) sulfone, benzidine, o-tolidine, 2,4- Aromatic diamines such as tolylene diamine, 2,6-tolylene diamine, xylylene diamine and naphthalene diamine can be mentioned.
　活物質層中の結着剤の配合割合は、質量比で、活物質：結着剤＝１：０．００１～１：０．３であるのが好ましく、１：０．００５～１：０．２であるのがより好ましく、１：０．０１～１：０．１５であるのがさらに好ましい。結着剤が少なすぎると電極の成形性が低下し、また、結着剤が多すぎると電極のエネルギー密度が低くなるためである。 The blending ratio of the binder in the active material layer is, in mass ratio, preferably active material: binder 1: 0.001 to 1: 0.3, 1: 0.005 to 1: 0 It is more preferably 0.2, and more preferably 1: 0.01 to 1: 0.15. When the amount of the binder is too small, the formability of the electrode decreases, and when the amount of the binder is too large, the energy density of the electrode decreases.
　負極は、集電体と、集電体の表面に結着させた負極活物質層を有する。集電体については、正極で説明したものを適宜適切に採用すれば良い。負極活物質層は負極活物質、並びに必要に応じて導電助剤及び／又は結着剤を含む。 The negative electrode includes a current collector and a negative electrode active material layer bonded to the surface of the current collector. As the current collector, one described for the positive electrode may be appropriately adopted appropriately. The negative electrode active material layer contains a negative electrode active material and, if necessary, a conductive aid and / or a binder.
　負極活物質としては、本発明のＡｌ含有シリコン材料のみを採用してもよいし、本発明のＡｌ含有シリコン材料と公知の負極活物質を併用してもよい。本発明のＡｌ含有シリコン材料を炭素で被覆したものを負極活物質として用いてもよい。 As the negative electrode active material, only the Al-containing silicon material of the present invention may be employed, or the Al-containing silicon material of the present invention may be used in combination with a known negative electrode active material. What coated Al content silicon material of the present invention with carbon may be used as a cathode active material.
　本発明のＡｌ含有シリコン材料の一態様である炭素被覆したＡｌ含有シリコン材料において、Ｃ質量％（ＷＣ％）は、０＜ＷＣ≦３０を満足するのが好ましく、１≦ＷＣ≦２０を満足するのがより好ましく、２≦ＷＣ≦１５を満足するのがさらに好ましく、５≦ＷＣ≦１０を満足するのが特に好ましい。 In the carbon-coated Al-containing silicon material which is one aspect of the Al-containing silicon material of the present invention, C mass% (W C %) preferably satisfies 0 <W C ≦ 30, 1 ≦ W C ≦ 20. Is more preferable, 2 ≦ W c ≦ 15 is more preferable, and 5 ≦ W c ≦ 10 is particularly preferable.
　負極に用いる導電助剤及び結着剤については、正極で説明したものを同様の配合割合で適宜適切に採用すれば良い。 As the conductive auxiliary and the binder used for the negative electrode, those described for the positive electrode may be appropriately adopted at the same mixing ratio.
　集電体の表面に活物質層を形成させるには、ロールコート法、ダイコート法、ディップコート法、ドクターブレード法、スプレーコート法、カーテンコート法などの従来から公知の方法を用いて、集電体の表面に活物質を塗布すればよい。具体的には、活物質、溶剤、並びに必要に応じて結着剤及び／又は導電助剤を混合し、スラリーを調製する。上記溶剤としては、Ｎ－メチル－２－ピロリドン、メタノール、メチルイソブチルケトン、水を例示できる。該スラリーを集電体の表面に塗布後、乾燥する。電極密度を高めるべく、乾燥後のものを圧縮しても良い。 In order to form an active material layer on the surface of a current collector, current collection can be performed using conventionally known methods such as roll coating, die coating, dip coating, doctor blade method, spray coating, and curtain coating. The active material may be applied to the surface of the body. Specifically, the active material, the solvent, and, if necessary, the binder and / or the conductive auxiliary agent are mixed to prepare a slurry. Examples of the solvent include N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone and water. The slurry is applied to the surface of a current collector and then dried. The dried one may be compressed to increase the electrode density.
　電解液は、非水溶媒と非水溶媒に溶解した電解質とを含んでいる。 The electrolytic solution contains a non-aqueous solvent and an electrolyte dissolved in the non-aqueous solvent.
　非水溶媒としては、環状エステル類、鎖状エステル類、エーテル類等が使用できる。環状エステル類としては、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、フルオロエチレンカーボネート、ガンマブチロラクトン、ビニレンカーボネート、２－メチル－ガンマブチロラクトン、アセチル－ガンマブチロラクトン、ガンマバレロラクトンを例示できる。鎖状エステル類としては、ジメチルカーボネート、ジエチルカーボネート、ジブチルカーボネート、ジプロピルカーボネート、エチルメチルカーボネート、プロピオン酸アルキルエステル、マロン酸ジアルキルエステル、酢酸アルキルエステル等を例示できる。エーテル類としては、テトラヒドロフラン、２－メチルテトラヒドロフラン、１，４－ジオキサン、１，２－ジメトキシエタン、１，２－ジエトキシエタン、１，２－ジブトキシエタンを例示できる。非水溶媒としては、上記具体的な溶媒の化学構造のうち一部又は全部の水素がフッ素に置換した化合物を採用しても良い。 As the non-aqueous solvent, cyclic esters, linear esters, ethers and the like can be used. Examples of cyclic esters include ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, gamma-butyrolactone, vinylene carbonate, 2-methyl-gamma-butyrolactone, acetyl-gamma-butyrolactone and gamma-valerolactone. Examples of the chain ester include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, ethyl methyl carbonate, alkyl propionic acid ester, malonic acid dialkyl ester, acetic acid alkyl ester and the like. As the ethers, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane can be exemplified. As the non-aqueous solvent, a compound in which part or all of hydrogens in the chemical structure of the above specific solvent is substituted with fluorine may be adopted.
　電解質としては、ＬｉＣｌＯ４、ＬｉＡｓＦ６、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＣＦ３ＳＯ２）２等のリチウム塩を例示できる。 Examples of the electrolyte include lithium salts such as LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiCF 3 SO 3 , and LiN (CF 3 SO 2 ) 2 .
　電解液としては、フルオロエチレンカーボネート、エチルメチルカーボネート、エチレンカーボネート、ジメチルカーボネート、プロピレンカーボネート、ジエチルカーボネートなどの非水溶媒に、ＬｉＣｌＯ４、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３などのリチウム塩を０．５ｍｏｌ／Ｌから３ｍｏｌ／Ｌ程度の濃度で溶解させた溶液を例示できる。 As the electrolytic solution, lithium salts such as LiClO 4 , LiPF 6 , LiBF 4 , LiCF 3 SO 3 and the like in a nonaqueous solvent such as fluoroethylene carbonate, ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate, propylene carbonate, diethyl carbonate A solution dissolved at a concentration of about 5 mol / L to 3 mol / L can be exemplified.
　セパレータは、正極と負極とを隔離し、両極の接触による短絡を防止しつつ、リチウムイオンを通過させるものである。セパレータとしては、ポリテトラフルオロエチレン、ポリプロピレン、ポリエチレン、ポリイミド、ポリアミド、ポリアラミド（Ａｒｏｍａｔｉｃ　ｐｏｌｙａｍｉｄｅ）、ポリエステル、ポリアクリロニトリル等の合成樹脂、セルロース、アミロース等の多糖類、フィブロイン、ケラチン、リグニン、スベリン等の天然高分子、セラミックスなどの電気絶縁性材料を１種若しくは複数用いた多孔体、不織布、織布などを挙げることができる。また、セパレータは多層構造としてもよい。 The separator separates the positive electrode and the negative electrode, and allows lithium ions to pass while preventing a short circuit due to the contact of the both electrodes. As a separator, synthetic resins such as polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamide, polyaramid (Aromatic polyamide), polyester, polyacrylonitrile, etc., polysaccharides such as cellulose and amylose, natural substances such as fibroin, keratin, lignin and suberin Examples thereof include porous bodies, non-woven fabrics, and woven fabrics using one or more kinds of electrically insulating materials such as polymers and ceramics. In addition, the separator may have a multilayer structure.
　次に、リチウムイオン二次電池の製造方法について説明する。 Next, a method of manufacturing a lithium ion secondary battery will be described.
　正極および負極に必要に応じてセパレータを挟装させ電極体とする。電極体は、正極、セパレータ及び負極を重ねた積層型、又は、正極、セパレータ及び負極を捲いた捲回型のいずれの型にしても良い。正極の集電体および負極の集電体から、外部に通ずる正極端子および負極端子までの間を、集電用リード等を用いて接続した後に、電極体に電解液を加えてリチウムイオン二次電池とするとよい。また、本発明のリチウムイオン二次電池は、電極に含まれる活物質の種類に適した電圧範囲で充放電を実行されればよい。 A separator is sandwiched between the positive electrode and the negative electrode as necessary to form an electrode body. The electrode body may be any of a laminated type in which the positive electrode, the separator and the negative electrode are stacked, or a wound type in which the positive electrode, the separator and the negative electrode are wound. After connecting from the current collector of the positive electrode and the current collector of the negative electrode to the positive electrode terminal and the negative electrode terminal leading to the outside using a lead for current collection etc., an electrolytic solution is added to the electrode body to make a secondary lithium ion It is good to use a battery. Further, the lithium ion secondary battery of the present invention may be charged and discharged in a voltage range suitable for the type of active material contained in the electrode.
　本発明のリチウムイオン二次電池の形状は特に限定されるものでなく、円筒型、角型、コイン型、ラミネート型等、種々の形状を採用することができる。 The shape of the lithium ion secondary battery of the present invention is not particularly limited, and various shapes such as cylindrical, square, coin, and laminate types can be adopted.
　本発明のリチウムイオン二次電池は、車両に搭載してもよい。車両は、その動力源の全部あるいは一部にリチウムイオン二次電池による電気エネルギーを使用している車両であればよく、たとえば、電気車両、ハイブリッド車両などであるとよい。車両にリチウムイオン二次電池を搭載する場合には、リチウムイオン二次電池を複数直列に接続して組電池とするとよい。リチウムイオン二次電池を搭載する機器としては、車両以外にも、パーソナルコンピュータ、携帯通信機器など、電池で駆動される各種の家電製品、オフィス機器、産業機器などが挙げられる。さらに、本発明のリチウムイオン二次電池は、風力発電、太陽光発電、水力発電その他電力系統の蓄電装置及び電力平滑化装置、船舶等の動力及び／又は補機類の電力供給源、航空機、宇宙船等の動力及び／又は補機類の電力供給源、電気を動力源に用いない車両の補助用電源、移動式の家庭用ロボットの電源、システムバックアップ用電源、無停電電源装置の電源、電動車両用充電ステーションなどにおいて充電に必要な電力を一時蓄える蓄電装置に用いてもよい。 The lithium ion secondary battery of the present invention may be mounted on a vehicle. The vehicle may be a vehicle using electric energy from a lithium ion secondary battery for all or part of its power source, and may be, for example, an electric vehicle, a hybrid vehicle, or the like. When a lithium ion secondary battery is mounted on a vehicle, a plurality of lithium ion secondary batteries may be connected in series to form a battery pack. As an apparatus which mounts a lithium ion secondary battery, various household appliances driven by a battery, such as a personal computer and a mobile communication apparatus, as well as a vehicle, an office apparatus, an industrial apparatus and the like can be mentioned. Furthermore, the lithium ion secondary battery of the present invention can be used in wind power generation, solar power generation, hydroelectric power generation, storage devices and power smoothing devices for electric power systems, power sources for power and / or accessories of ships, etc., aircraft, Power supply source for power of spacecraft and / or accessories, auxiliary power supply for vehicles not using electricity as power source, power supply for mobile home robots, power supply for system backup, power supply for uninterruptible power supply, You may use for the electrical storage apparatus which stores temporarily the electric power required for charge in the charge station etc. for electric vehicles.
　以上、本発明の実施形態を説明したが、本発明は、上記実施形態に限定されるものではない。本発明の要旨を逸脱しない範囲において、当業者が行い得る変更、改良等を施した種々の形態にて実施することができる。 As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. In the range which does not deviate from the summary of the present invention, it can carry out with various forms which gave change, improvement, etc. which a person skilled in the art can make.
　以下に、実施例および比較例などを示し、本発明をより具体的に説明する。なお、本発明は、これらの実施例によって限定されるものではない。 Hereinafter, the present invention will be described more specifically by showing Examples and Comparative Examples. The present invention is not limited by these examples.
　（実施例１）
　以下のとおり、実施例１のＡｌ含有シリコン材料及びリチウムイオン二次電池を製造した。 Example 1
The Al-containing silicon material and lithium ion secondary battery of Example 1 were manufactured as follows.
　ａ）工程
　Ｃａ、Ａｌ及びＳｉを炭素坩堝に秤量した。Ｃａ及びＳｉの元素組成比は１：２であり、Ａｌの添加量はＣａ、Ａｌ及びＳｉの全体の質量に対して１％とした。アルゴンガス雰囲気下の高周波誘導加熱装置にて、炭素坩堝を１３００℃付近で加熱してＣａ、Ａｌ及びＳｉを含む溶湯とした。前記溶湯を所定の鋳型に注湯することで冷却して固体とした。当該固体を粉砕して粉末状にした後に、ｂ）工程に供した。 a) Step Ca, Al and Si were weighed in a carbon crucible. The elemental composition ratio of Ca and Si was 1: 2, and the amount of Al added was 1% with respect to the total mass of Ca, Al and Si. A carbon crucible was heated at around 1300 ° C. in a high frequency induction heating apparatus under an argon gas atmosphere to obtain a molten metal containing Ca, Al and Si. The molten metal is poured into a predetermined mold to cool and solidify. The solid was pulverized into a powder and then subjected to the step b).
　ｂ）工程
　窒素ガス雰囲気下にて、０℃の１７ｗｔ％塩酸に、ａ）工程で得られた粉末状の固体を加え、撹拌した。反応液を濾過し、残渣を蒸留水及びメタノールで洗浄し、さらに、室温で減圧乾燥してＡｌ含有シリコン材料の前駆体を得た。 b) Process In a nitrogen gas atmosphere, the powdery solid obtained in the process a) was added to 17 wt% hydrochloric acid at 0 ° C. and stirred. The reaction solution was filtered, and the residue was washed with distilled water and methanol, and further dried at room temperature under reduced pressure to obtain a precursor of an Al-containing silicon material.
　ｃ）工程
　Ａｌ含有シリコン材料の前駆体を、窒素ガス雰囲気下、９００℃で１時間加熱して、実施例１のＡｌ含有シリコン材料を製造した。 c) Process The Al-containing silicon material of Example 1 was manufactured by heating the precursor of the Al-containing silicon material at 900 ° C. for 1 hour under a nitrogen gas atmosphere.
　実施例１のＡｌ含有シリコン材料を用いて、以下のとおり、実施例１の負極及び実施例１のリチウムイオン二次電池を製造した。 Using the Al-containing silicon material of Example 1, the negative electrode of Example 1 and the lithium ion secondary battery of Example 1 were produced as follows.
　重量平均分子量８０万のポリアクリル酸をＮ－メチル－２－ピロリドンに溶解して、ポリアクリル酸が１０質量％で含有されるポリアクリル酸溶液を製造した。また、４，４’－ジアミノジフェニルメタン０．２ｇ（１．０ｍｍｏｌ）を０．４ｍＬのＮ－メチル－２－ピロリドンに溶解して、４，４’－ジアミノジフェニルメタン溶液を製造した。撹拌条件下、ポリアクリル酸溶液７ｍＬ（アクリル酸モノマー換算で、９．５ｍｍｏｌに該当する。）に、４，４’－ジアミノジフェニルメタン溶液の全量を滴下して、得られた混合物を室温で３０分間撹拌した。その後、ディーンスターク装置を用いて、混合物を１３０℃で３時間撹拌して脱水反応を進行させることで、結着剤溶液を製造した。 A polyacrylic acid having a weight average molecular weight of 800,000 was dissolved in N-methyl-2-pyrrolidone to prepare a polyacrylic acid solution containing 10% by mass of polyacrylic acid. In addition, a solution of 4,4'-diaminodiphenylmethane was prepared by dissolving 0.2 g (1.0 mmol) of 4,4'-diaminodiphenylmethane in 0.4 mL of N-methyl-2-pyrrolidone. Under stirring conditions, the entire amount of 4,4'-diaminodiphenylmethane solution is added dropwise to 7 mL of a polyacrylic acid solution (corresponding to 9.5 mmol in terms of acrylic acid monomer), and the resulting mixture is allowed to stand at room temperature for 30 minutes. It stirred. Then, using a Dean-Stark apparatus, the mixture was stirred at 130 ° C. for 3 hours to allow the dehydration reaction to proceed, thereby producing a binder solution.
　負極活物質として実施例１のＡｌ含有シリコン材料７２．５質量部、導電助剤としてアセチレンブラック１３．５質量部、結着剤として固形分が１４質量部となる量の上記結着剤溶液、及び、適量のＮ－メチル－２－ピロリドンを混合して、スラリーを製造した。負極用集電体として銅箔を準備した。この銅箔の表面に、ドクターブレードを用いて、上記スラリーを膜状に塗布した。スラリーが塗布された銅箔を８０℃、１５分間乾燥することで、Ｎ－メチル－２－ピロリドンを除去した。その後、プレスし、真空ポンプによる減圧雰囲気で１８０℃、３０分加熱することで、負極活物質層が形成された実施例１の負極を製造した。 72.5 parts by mass of the Al-containing silicon material of Example 1 as a negative electrode active material, 13.5 parts by mass of acetylene black as a conduction aid, and 14 parts by mass of a solid content as a binder And, an appropriate amount of N-methyl-2-pyrrolidone was mixed to prepare a slurry. A copper foil was prepared as a current collector for the negative electrode. The slurry was applied in the form of a film on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried at 80 ° C. for 15 minutes to remove N-methyl-2-pyrrolidone. Thereafter, the resultant was pressed and heated at 180 ° C. for 30 minutes in a reduced pressure atmosphere using a vacuum pump to manufacture the negative electrode of Example 1 in which the negative electrode active material layer was formed.
　正極活物質としてＬｉＮｉ８２／１００Ｃｏ１５／１００Ａｌ３／１００Ｏ２を９６質量部、導電助剤としてアセチレンブラック２質量部、結着剤としてポリフッ化ビニリデン２質量部、及び適量のＮ－メチル－２－ピロリドンを混合して、スラリーを製造した。正極用集電体としてアルミニウム箔を準備した。このアルミニウム箔の表面に、ドクターブレードを用いて上記スラリーが膜状になるように塗布した。スラリーが塗布されたアルミニウム箔を８０℃で２０分間乾燥することで、Ｎ－メチル－２－ピロリドンを除去した。その後、プレスし、真空ポンプによる減圧雰囲気で１２０℃、６時間加熱することで、正極活物質層が集電体の表面に形成された正極を製造した。 96 parts by mass of LiNi 82/100 Co 15/100 Al 3/100 O 2 as a positive electrode active material, 2 parts by mass of acetylene black as a conduction aid, 2 parts by mass of polyvinylidene fluoride as a binder, and an appropriate amount of N-methyl The -2-pyrrolidone was mixed to produce a slurry. An aluminum foil was prepared as a positive electrode current collector. The slurry was applied in the form of a film on the surface of the aluminum foil using a doctor blade. The N-methyl-2-pyrrolidone was removed by drying the slurry-coated aluminum foil at 80 ° C. for 20 minutes. Then, the resultant was pressed and heated at 120 ° C. for 6 hours in a reduced pressure atmosphere using a vacuum pump to manufacture a positive electrode having a positive electrode active material layer formed on the surface of the current collector.
　セパレータとして、ポリエチレン製多孔質膜を準備した。また、フルオロエチレンカーボネート及びエチルメチルカーボネートを体積比１９：８１で混合した混合溶媒に、ＬｉＰＦ６を濃度２ｍｏｌ／Ｌで溶解した溶液を、電解液とした。 A polyethylene porous membrane was prepared as a separator. In addition, a solution in which LiPF 6 was dissolved at a concentration of 2 mol / L in a mixed solvent in which fluoroethylene carbonate and ethyl methyl carbonate were mixed at a volume ratio of 19: 81 was used as an electrolytic solution.
　実施例１の負極、セパレータ、正極の順に積層して、積層体とした。この積層体及び電解液をラミネートフィルム製の袋に収容して、袋を密閉し、実施例１のリチウムイオン二次電池を製造した。 It laminated | stacked in order of the negative electrode of Example 1, a separator, and the positive electrode, and was set as the laminated body. The laminate and the electrolytic solution were placed in a laminate film bag, the bag was sealed, and the lithium ion secondary battery of Example 1 was manufactured.
　（比較例１）
　ａ）工程において、Ａｌを添加しなかったこと以外は、実施例１と同様の方法で、比較例１のシリコン材料、比較例１の負極、比較例１のリチウムイオン二次電池を製造した。 (Comparative example 1)
In the step a), the silicon material of Comparative Example 1, the negative electrode of Comparative Example 1, and the lithium ion secondary battery of Comparative Example 1 were produced in the same manner as in Example 1 except that Al was not added.
　（評価例１）
　誘導結合プラズマ発光分析装置（ＩＣＰ－ＡＥＳ）を用いて、実施例１のＡｌ含有シリコン材料と、比較例１のシリコン材料の元素分析を行った。元素分析の結果、実施例１のＡｌ含有シリコン材料におけるＡｌ質量％は０．２５％、Ｆｅ質量％は０％であり、比較例１のシリコン材料におけるＡｌ質量％は０％、Ｆｅ質量％は０％であった。 (Evaluation example 1)
Elemental analysis of the Al-containing silicon material of Example 1 and the silicon material of Comparative Example 1 was performed using an inductively coupled plasma atomic emission spectrometer (ICP-AES). As a result of elemental analysis, the Al mass% in the Al-containing silicon material of Example 1 is 0.25% and the Fe mass% is 0%, and the Al mass% in the silicon material of Comparative Example 1 is 0%, Fe mass% It was 0%.
　（評価例２）
　２５℃の恒温層中で、実施例１のリチウムイオン二次電池をＳＯＣ（Ｓｔａｔｅ　ｏｆ　Ｃｈａｒｇｅ）１５％に調整した。そして、１Ｃレートの一定電流で、当該リチウムイオン二次電池を１０秒間放電させた。放電前後の電圧の変化量を、電流値で除して、抵抗を算出した。比較例１のリチウムイオン二次電池についても同様の試験を行った。
　実施例１のリチウムイオン二次電池の抵抗は３．３Ωであり、比較例１のリチウムイオン二次電池の抵抗は３．６Ωであった。Ａｌ含有シリコン材料を用いることで、リチウムイオン二次電池の抵抗が低下することが裏付けられた。 (Evaluation example 2)
The lithium ion secondary battery of Example 1 was adjusted to an SOC (State of Charge) of 15% in a thermostat of 25 ° C. Then, the lithium ion secondary battery was discharged for 10 seconds at a constant current of 1 C rate. The resistance was calculated by dividing the amount of change in voltage before and after discharge by the current value. The same test was performed on the lithium ion secondary battery of Comparative Example 1.
The resistance of the lithium ion secondary battery of Example 1 was 3.3Ω, and the resistance of the lithium ion secondary battery of Comparative Example 1 was 3.6Ω. It was confirmed that the resistance of the lithium ion secondary battery is lowered by using the Al-containing silicon material.
　（実施例２）
　以下のとおり、実施例２のＡｌ含有シリコン材料、負極及びリチウムイオン二次電池を製造した。 (Example 2)
The Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 2 were manufactured as follows.
　ａ）工程
　Ｃａ、Ａｌ及びＳｉを炭素坩堝に秤量した。Ｃａ及びＳｉの元素組成比は１：２であり、Ａｌの添加量はＣａ、Ａｌ及びＳｉの全体の質量に対して１％とした。アルゴンガス雰囲気下の高周波誘導加熱装置にて、炭素坩堝を１３００℃付近で加熱してＣａ、Ａｌ及びＳｉを含む溶湯とした。前記溶湯を所定の鋳型に注湯して冷却して固体とした。当該固体を粉砕して粉末状にした後に、ｂ）工程に供した。 a) Step Ca, Al and Si were weighed in a carbon crucible. The elemental composition ratio of Ca and Si was 1: 2, and the amount of Al added was 1% with respect to the total mass of Ca, Al and Si. A carbon crucible was heated at around 1300 ° C. in a high frequency induction heating apparatus under an argon gas atmosphere to obtain a molten metal containing Ca, Al and Si. The molten metal is poured into a predetermined mold and cooled to form a solid. The solid was pulverized into a powder and then subjected to the step b).
　ｂ）工程
　窒素ガス雰囲気下にて、０℃の１７ｗｔ％塩酸に、ａ）工程で得られた粉末状の固体を加え、撹拌した。反応液を濾過し、残渣を蒸留水及びメタノールで洗浄し、さらに、室温で減圧乾燥してＡｌ含有シリコン材料の前駆体を得た。 b) Process In a nitrogen gas atmosphere, the powdery solid obtained in the process a) was added to 17 wt% hydrochloric acid at 0 ° C. and stirred. The reaction solution was filtered, and the residue was washed with distilled water and methanol, and further dried at room temperature under reduced pressure to obtain a precursor of an Al-containing silicon material.
　ｃ）工程
　Ａｌ含有シリコン材料の前駆体を、窒素ガス雰囲気下、９００℃で１時間加熱して、実施例２のＡｌ含有シリコン材料を製造した。 c) Step The Al-containing silicon material of Example 2 was manufactured by heating the precursor of the Al-containing silicon material at 900 ° C. for 1 hour in a nitrogen gas atmosphere.
　実施例２のＡｌ含有シリコン材料を用いて、以下のとおり、実施例２の負極及び実施例２のリチウムイオン二次電池を製造した。 Using the Al-containing silicon material of Example 2, the negative electrode of Example 2 and the lithium ion secondary battery of Example 2 were manufactured as follows.
　重量平均分子量８０万のポリアクリル酸をＮ－メチル－２－ピロリドンに溶解して、ポリアクリル酸が１０質量％で含有されるポリアクリル酸溶液を製造した。また、４，４’－ジアミノジフェニルメタン０．２ｇ（１．０ｍｍｏｌ）を０．４ｍＬのＮ－メチル－２－ピロリドンに溶解して、４，４’－ジアミノジフェニルメタン溶液を製造した。撹拌条件下、ポリアクリル酸溶液７ｍＬ（アクリル酸モノマー換算で、９．５ｍｍｏｌに該当する。）に、４，４’－ジアミノジフェニルメタン溶液の全量を滴下して、得られた混合物を室温で３０分間撹拌した。その後、ディーンスターク装置を用いて、混合物を１３０℃で３時間撹拌して脱水反応を進行させることで、結着剤溶液を製造した。 A polyacrylic acid having a weight average molecular weight of 800,000 was dissolved in N-methyl-2-pyrrolidone to prepare a polyacrylic acid solution containing 10% by mass of polyacrylic acid. In addition, a solution of 4,4'-diaminodiphenylmethane was prepared by dissolving 0.2 g (1.0 mmol) of 4,4'-diaminodiphenylmethane in 0.4 mL of N-methyl-2-pyrrolidone. Under stirring conditions, the entire amount of 4,4'-diaminodiphenylmethane solution is added dropwise to 7 mL of a polyacrylic acid solution (corresponding to 9.5 mmol in terms of acrylic acid monomer), and the resulting mixture is allowed to stand at room temperature for 30 minutes. It stirred. Then, using a Dean-Stark apparatus, the mixture was stirred at 130 ° C. for 3 hours to allow the dehydration reaction to proceed, thereby producing a binder solution.
　負極活物質として実施例２のＡｌ含有シリコン材料７２．５質量部、導電助剤としてアセチレンブラック１３．５質量部、結着剤として固形分が１４質量部となる量の上記結着剤溶液、及び、適量のＮ－メチル－２－ピロリドンを混合して、スラリーを製造した。負極用集電体として銅箔を準備した。この銅箔の表面に、ドクターブレードを用いて、上記スラリーを膜状に塗布した。スラリーが塗布された銅箔を８０℃、１５分間乾燥することで、Ｎ－メチル－２－ピロリドンを除去した。その後、プレスし、真空ポンプによる減圧雰囲気で１８０℃、３０分加熱することで、負極活物質層が形成された実施例２の負極を製造した。 72.5 parts by mass of the Al-containing silicon material of Example 2 as a negative electrode active material, 13.5 parts by mass of acetylene black as a conduction aid, and 14 parts by mass of a solid content as a binder And, an appropriate amount of N-methyl-2-pyrrolidone was mixed to prepare a slurry. A copper foil was prepared as a current collector for the negative electrode. The slurry was applied in the form of a film on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried at 80 ° C. for 15 minutes to remove N-methyl-2-pyrrolidone. After that, pressing was performed and heating was performed at 180 ° C. for 30 minutes in a reduced pressure atmosphere using a vacuum pump to manufacture the negative electrode of Example 2 in which the negative electrode active material layer was formed.
　実施例２の負極を径１１ｍｍに裁断し、評価極とした。厚さ５００μｍの金属リチウム箔を径１３ｍｍに裁断し対極とした。セパレータとしてガラスフィルター（ヘキストセラニーズ社）及び単層ポリプロピレンであるｃｅｌｇａｒｄ２４００（ポリポア株式会社）を準備した。また、エチレンカーボネート及びジエチルカーボネートを体積比１：１で混合した混合溶媒にＬｉＰＦ6を濃度１ｍｏｌ／Ｌで溶解した電解液を準備した。対極、ガラスフィルター、ｃｅｌｇａｒｄ２４００、評価極の順に、２種のセパレータを対極と評価極で挟持し電極体とした。この電極体をコイン型電池ケースＣＲ２０３２（宝泉株式会社）に収容し、さらに電解液を注入して、コイン型電池を得た。これを実施例２のリチウムイオン二次電池とした。 The negative electrode of Example 2 was cut to a diameter of 11 mm to obtain an evaluation electrode. A metal lithium foil having a thickness of 500 μm was cut to a diameter of 13 mm and used as a counter electrode. A glass filter (Hoechst Celanese) and celgard 2400 (Polypore Co., Ltd.) which is a single-layer polypropylene were prepared as a separator. The volume ratio of ethylene carbonate and diethyl carbonate 1: LiPF 6 was prepared the electrolytic solution at a concentration 1 mol / L in a mixed solvent obtained by mixing 1. The two types of separators were sandwiched between the counter electrode and the evaluation electrode in the order of the counter electrode, the glass filter, celgard 2400, and the evaluation electrode to form an electrode body. The electrode body was housed in a coin-type battery case CR2032 (Housen Co., Ltd.), and an electrolyte was further injected to obtain a coin-type battery. The resultant was used as a lithium ion secondary battery of Example 2.
　（実施例３）
　製造スケールを大きくした点、及び、ｃ）工程の後に以下の炭素被覆工程を加えて、炭素被覆されたＡｌ含有シリコン材料を実施例３のＡｌ含有シリコン材料とし、これを負極活物質として用いた点以外は、実施例２と同様の方法で、実施例３のＡｌ含有シリコン材料、負極及びリチウムイオン二次電池を製造した。 (Example 3)
The following carbon coating process was added after the process c) with the point of increasing the production scale, and the carbon-coated Al-containing silicon material was used as the Al-containing silicon material of Example 3 and was used as a negative electrode active material. The Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 3 were manufactured in the same manner as in Example 2 except for the point.
　・炭素被覆工程
　ｃ）工程を経たＡｌ含有シリコン材料をロータリーキルン型の反応器に入れ、プロパン－アルゴン混合ガスの通気下にて８８０℃、滞留時間６０分間の条件で熱ＣＶＤを行い、炭素被覆されたＡｌ含有シリコン材料を得た。 Carbon Coating Step c) The Al-containing silicon material obtained in step c) is placed in a rotary kiln type reactor, and thermal CVD is performed at 880 ° C. for 60 minutes under aeration of propane-argon mixed gas, thereby carbon coating An Al-containing silicon material was obtained.
　（実施例４）
　不純物としてＡｌ及びＦｅを含有する粉末状のＣａＳｉ２を準備した。ＩＣＰ－ＡＥＳを用いて当該ＣａＳｉ２の元素分析を行ったところ、Ｃａ：３８質量％、Ｓｉ：５７質量％、Ｆｅ：４質量％、Ａｌ：１質量％であった。
　当該ＣａＳｉ２を用いてｂ）工程以下を実施した以外は、実施例３と同様の方法で、実施例４のＡｌ含有シリコン材料、負極及びリチウムイオン二次電池を製造した。 (Example 4)
Powdered CaSi 2 containing Al and Fe as impurities was prepared. When elemental analysis of the CaSi 2 was performed using ICP-AES, it was 38 mass% of Ca, 57 mass% of Si, 4 mass% of Fe, and 1 mass% of Al.
The Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 4 were manufactured in the same manner as in Example 3 except that step b) and the following steps were performed using the CaSi 2 .
　（比較例２）
　ａ）工程において、Ａｌを添加しなかったこと以外は、実施例２と同様の方法で、比較例２のシリコン材料、負極及びリチウムイオン二次電池を製造した。 (Comparative example 2)
The silicon material, the negative electrode, and the lithium ion secondary battery of Comparative Example 2 were manufactured in the same manner as in Example 2 except that Al was not added in the step a).
　（比較例３）
　ａ）工程において、Ａｌを添加せず、Ｆｅを添加したこと以外は、実施例２と同様の方法で、比較例３のシリコン材料、負極及びリチウムイオン二次電池を製造した。　なお、ａ）工程のＦｅは、Ｃａ、Ｆｅ及びＳｉの全体の質量に対して４％となる量で添加した。 (Comparative example 3)
In the step a), the silicon material, the negative electrode, and the lithium ion secondary battery of Comparative Example 3 were manufactured in the same manner as in Example 2 except that Al was not added and Fe was added. In addition, Fe in the step a) was added in an amount of 4% with respect to the total mass of Ca, Fe and Si.
　（評価例３）
　蛍光Ｘ線分析装置（ＸＲＦ）を用いて、実施例２～実施例４のＡｌ含有シリコン材料と、比較例２及び比較例３のシリコン材料の元素分析を行った。また、酸素・窒素・水素分析装置を用いて、実施例２～実施例４のＡｌ含有シリコン材料と、比較例２及び比較例３のシリコン材料に対して、酸素を対象とした元素分析を行った。さらに、炭素・硫黄分析装置を用いて、炭素被覆された実施例３及び実施例４のＡｌ含有シリコン材料に対して、炭素を対象とした元素分析を行った。 (Evaluation example 3)
Elemental analysis was performed on the Al-containing silicon materials of Examples 2 to 4 and the silicon materials of Comparative Examples 2 and 3 using a fluorescent X-ray analyzer (XRF). In addition, elemental analysis of oxygen was performed on the Al-containing silicon materials of Examples 2 to 4 and the silicon materials of Comparative Examples 2 and 3 using an oxygen / nitrogen / hydrogen analyzer. The Furthermore, elemental analysis for carbon was performed on the carbon-coated Al-containing silicon materials of Example 3 and Example 4 using a carbon / sulfur analyzer.
　これらの元素分析の結果を、質量％として、表１に示す。実施例２、実施例３、比較例２に若干量のＦｅが存在するのは、原料の金属にＦｅが不純物として含まれていたためである。また、すべてのシリコン材料に含まれているＯ、Ｃａ及びＣｌは、製造で使用した溶媒（水）、原料、酸のアニオンなどに由来する。　 The results of these elemental analyzes are shown in Table 1 as mass%. The presence of a slight amount of Fe in Example 2, Example 3, and Comparative Example 2 is because Fe is contained as an impurity in the metal of the raw material. Further, O, Ca and Cl contained in all silicon materials are derived from the solvent (water) used in the production, the raw material, the anion of the acid and the like.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　（評価例４）
　粉末Ｘ線回折装置にて、実施例２のＡｌ含有シリコン材料のＸ線回折を測定した。
　その結果、実施例２のＡｌ含有シリコン材料のＸ線回折チャートから、シリコン結晶子に由来するピークが確認できた。 (Evaluation example 4)
The X-ray diffraction of the Al-containing silicon material of Example 2 was measured with a powder X-ray diffractometer.
As a result, from the X-ray diffraction chart of the Al-containing silicon material of Example 2, a peak derived from silicon crystallite could be confirmed.
　（評価例５）
　実施例２～実施例４、比較例２及び比較例３のリチウムイオン二次電池に対して、電流０．２ｍＡで０．０１Ｖまで放電を行い、その後、電流０．２ｍＡで０．８Ｖまで充電を行うとの初回充放電を行った。
　さらに、初回充放電後の実施例２、比較例２及び比較例３のリチウムイオン二次電池につき、電流０．５ｍＡで０．０１Ｖまで放電を行い、その後、電流０．５ｍＡで１．０Ｖまで充電を行うとの充放電サイクルを複数回行った。 (Evaluation example 5)
The lithium ion secondary batteries of Examples 2 to 4 and Comparative Examples 2 and 3 were discharged to 0.01 V at a current of 0.2 mA, and then charged to 0.8 V at a current of 0.2 mA. The first charge and discharge was performed.
Furthermore, the lithium ion secondary batteries of Example 2 and Comparative Examples 2 and 3 after the initial charge and discharge were discharged to 0.01 V at a current of 0.5 mA, and then to 1.0 V at a current of 0.5 mA. A plurality of charge and discharge cycles for charging were performed.
　初期効率及び容量維持率を以下の各式で算出した。
　初期効率（％）＝１００×（初回充電容量）／（初回放電容量）
　容量維持率（％）＝１００×（各サイクル時の充電容量）／（１サイクル目の充電容量）
　初回放電容量、初回充電容量及び初期効率の結果を、元素分析の結果の一部とともに表２に示す。また、容量維持率の結果（Ｎ＝２）を図２に示す。　 The initial efficiency and capacity retention rate were calculated by the following formulas.
Initial efficiency (%) = 100 × (initial charge capacity) / (initial discharge capacity)
Capacity retention rate (%) = 100 × (charge capacity at each cycle) / (charge capacity at first cycle)
The results of the initial discharge capacity, the initial charge capacity, and the initial efficiency are shown in Table 2 together with part of the elemental analysis results. Further, the result (N = 2) of the capacity retention rate is shown in FIG.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２の結果から、Ｆｅの存在に因り、初回放電容量、初回充電容量及び初期効率が低くなるといえる。また、図２の結果から、容量維持率の点からは、ＡｌやＦｅの存在が好ましいといえる。これらの結果から総合的に考察すると、本発明のＡｌ含有シリコン材料において、Ｆｅの存在量は少ない方が好ましく、Ａｌの存在量は多い方が好ましいと考えられる。 From the results in Table 2, it can be said that the initial discharge capacity, the initial charge capacity and the initial efficiency are lowered due to the presence of Fe. Further, from the results of FIG. 2, it can be said that the presence of Al and Fe is preferable from the viewpoint of the capacity retention rate. When considering these results comprehensively, in the Al-containing silicon material of the present invention, it is considered that the smaller the amount of Fe present is, the larger the amount of Al present is preferable.
　（実施例５）
　以下のとおり、実施例５のＡｌ含有シリコン材料、負極及びリチウムイオン二次電池を製造した。 (Example 5)
The Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 5 were produced as follows.
　ａ）工程
　Ｃａ、Ａｌ及びＳｉを炭素坩堝に秤量した。Ｃａ及びＳｉの元素組成比は１：２であり、Ａｌの添加量はＣａ、Ａｌ及びＳｉの全体の質量に対して０．１％とした。アルゴンガス雰囲気下の高周波誘導加熱装置にて、炭素坩堝を１３００℃付近で加熱してＣａ、Ａｌ及びＳｉを含む溶湯とした。前記溶湯を所定の鋳型に注湯して冷却して固体とした。当該固体を粉砕して粉末状にした後に、ｂ）工程に供した。 a) Step Ca, Al and Si were weighed in a carbon crucible. The elemental composition ratio of Ca and Si was 1: 2, and the amount of Al added was 0.1% with respect to the total mass of Ca, Al and Si. A carbon crucible was heated at around 1300 ° C. in a high frequency induction heating apparatus under an argon gas atmosphere to obtain a molten metal containing Ca, Al and Si. The molten metal is poured into a predetermined mold and cooled to form a solid. The solid was pulverized into a powder and then subjected to the step b).
　ｂ）工程
　窒素ガス雰囲気下にて、０℃の１７ｗｔ％塩酸に、ａ）工程で得られた粉末状の固体を加え、撹拌した。反応液を濾過し、残渣を蒸留水及びメタノールで洗浄し、さらに、室温で減圧乾燥してＡｌ含有シリコン材料の前駆体を得た。 b) Process In a nitrogen gas atmosphere, the powdery solid obtained in the process a) was added to 17 wt% hydrochloric acid at 0 ° C. and stirred. The reaction solution was filtered, and the residue was washed with distilled water and methanol, and further dried at room temperature under reduced pressure to obtain a precursor of an Al-containing silicon material.
　ｃ）工程
　Ａｌ含有シリコン材料の前駆体を、窒素ガス雰囲気下、９００℃で１時間加熱し、実施例５のＡｌ含有シリコン材料を製造した。 c) Step The Al-containing silicon material precursor of Example 5 was manufactured by heating the precursor of the Al-containing silicon material at 900 ° C. for 1 hour in a nitrogen gas atmosphere.
　実施例５のＡｌ含有シリコン材料を用いて、以下のとおり、実施例５の負極及び実施例５のリチウムイオン二次電池を製造した。 The negative electrode of Example 5 and the lithium ion secondary battery of Example 5 were manufactured as follows using the Al-containing silicon material of Example 5.
　重量平均分子量８０万のポリアクリル酸をＮ－メチル－２－ピロリドンに溶解して、ポリアクリル酸が１０質量％で含有されるポリアクリル酸溶液を製造した。また、４，４’－ジアミノジフェニルメタン０．２ｇ（１．０ｍｍｏｌ）を０．４ｍＬのＮ－メチル－２－ピロリドンに溶解して、４，４’－ジアミノジフェニルメタン溶液を製造した。撹拌条件下、ポリアクリル酸溶液７ｍＬ（アクリル酸モノマー換算で、９．５ｍｍｏｌに該当する。）に、４，４’－ジアミノジフェニルメタン溶液の全量を滴下して、得られた混合物を室温で３０分間撹拌した。その後、ディーンスターク装置を用いて、混合物を１３０℃で３時間撹拌して脱水反応を進行させることで、結着剤溶液を製造した。 A polyacrylic acid having a weight average molecular weight of 800,000 was dissolved in N-methyl-2-pyrrolidone to prepare a polyacrylic acid solution containing 10% by mass of polyacrylic acid. In addition, a solution of 4,4'-diaminodiphenylmethane was prepared by dissolving 0.2 g (1.0 mmol) of 4,4'-diaminodiphenylmethane in 0.4 mL of N-methyl-2-pyrrolidone. Under stirring conditions, the entire amount of 4,4'-diaminodiphenylmethane solution is added dropwise to 7 mL of a polyacrylic acid solution (corresponding to 9.5 mmol in terms of acrylic acid monomer), and the resulting mixture is allowed to stand at room temperature for 30 minutes. It stirred. Then, using a Dean-Stark apparatus, the mixture was stirred at 130 ° C. for 3 hours to allow the dehydration reaction to proceed, thereby producing a binder solution.
　負極活物質として実施例５のＡｌ含有シリコン材料７２．５質量部、導電助剤としてアセチレンブラック１３．５質量部、結着剤として固形分が１４質量部となる量の上記結着剤溶液、及び、適量のＮ－メチル－２－ピロリドンを混合して、スラリーを製造した。負極用集電体として銅箔を準備した。この銅箔の表面に、ドクターブレードを用いて、上記スラリーを膜状に塗布した。スラリーが塗布された銅箔を８０℃、１５分間乾燥することで、Ｎ－メチル－２－ピロリドンを除去した。その後、プレスし、真空ポンプによる減圧雰囲気で１８０℃、３０分加熱することで、負極活物質層が形成された実施例５の負極を製造した。 72.5 parts by mass of the Al-containing silicon material of Example 5 as a negative electrode active material, 13.5 parts by mass of acetylene black as a conduction aid, and 14 parts by mass of solid content as a binder And, an appropriate amount of N-methyl-2-pyrrolidone was mixed to prepare a slurry. A copper foil was prepared as a current collector for the negative electrode. The slurry was applied in the form of a film on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried at 80 ° C. for 15 minutes to remove N-methyl-2-pyrrolidone. After that, pressing was performed and heating was performed at 180 ° C. for 30 minutes in a reduced pressure atmosphere using a vacuum pump to manufacture the negative electrode of Example 5 in which the negative electrode active material layer was formed.
　実施例５の負極を径１１ｍｍに裁断し、評価極とした。厚さ５００μｍの金属リチウム箔を径１３ｍｍに裁断し対極とした。セパレータとしてガラスフィルター（ヘキストセラニーズ社）及び単層ポリプロピレンであるｃｅｌｇａｒｄ２４００（ポリポア株式会社）を準備した。また、エチレンカーボネート及びジエチルカーボネートを体積比１：１で混合した混合溶媒にＬｉＰＦ6を濃度１ｍｏｌ／Ｌで溶解した電解液を準備した。対極、ガラスフィルター、ｃｅｌｇａｒｄ２４００、評価極の順に、２種のセパレータを対極と評価極で挟持し電極体とした。この電極体をコイン型電池ケースＣＲ２０３２（宝泉株式会社）に収容し、さらに電解液を注入して、コイン型電池を得た。これを実施例５のリチウムイオン二次電池とした。 The negative electrode of Example 5 was cut to a diameter of 11 mm to obtain an evaluation electrode. A metal lithium foil having a thickness of 500 μm was cut to a diameter of 13 mm and used as a counter electrode. A glass filter (Hoechst Celanese) and celgard 2400 (Polypore Co., Ltd.) which is a single-layer polypropylene were prepared as a separator. The volume ratio of ethylene carbonate and diethyl carbonate 1: LiPF 6 was prepared the electrolytic solution at a concentration 1 mol / L in a mixed solvent obtained by mixing 1. The two types of separators were sandwiched between the counter electrode and the evaluation electrode in the order of the counter electrode, the glass filter, celgard 2400, and the evaluation electrode to form an electrode body. The electrode body was housed in a coin-type battery case CR2032 (Housen Co., Ltd.), and an electrolyte was further injected to obtain a coin-type battery. The resultant was used as a lithium ion secondary battery of Example 5.
　（実施例６）
　ａ）工程において、Ａｌの添加量をＣａ、Ａｌ及びＳｉの全体の質量に対して０．３％とした以外は、実施例５と同様の方法で、実施例６のＡｌ含有シリコン材料、負極及びリチウムイオン二次電池を製造した。 (Example 6)
Al-containing silicon material of Example 6, negative electrode in the same manner as in Example 5 except that in the step a), the amount of Al added is 0.3% with respect to the total mass of Ca, Al and Si And a lithium ion secondary battery.
　（実施例７）
　ａ）工程において、Ａｌの添加量をＣａ、Ａｌ及びＳｉの全体の質量に対して０．５％とした以外は、実施例５と同様の方法で、実施例７のＡｌ含有シリコン材料、負極及びリチウムイオン二次電池を製造した。 (Example 7)
Al-containing silicon material of Example 7, negative electrode in the same manner as in Example 5 except that in the step a), the amount of Al added is 0.5% with respect to the total mass of Ca, Al and Si And a lithium ion secondary battery.
　（実施例８）
　ａ）工程において、Ａｌの添加量をＣａ、Ａｌ及びＳｉの全体の質量に対して１％とした以外は、実施例５と同様の方法で、実施例８のＡｌ含有シリコン材料、負極及びリチウムイオン二次電池を製造した。 (Example 8)
Al-containing silicon material, negative electrode and lithium of Example 8 in the same manner as in Example 5 except that in the step a), the amount of Al added is 1% with respect to the total mass of Ca, Al and Si An ion secondary battery was manufactured.
　（実施例９）
　ａ）工程に以下のアニール工程を加えた以外は、実施例８と同様の方法で、実施例９のＡｌ含有シリコン材料、負極及びリチウムイオン二次電池を製造した。 (Example 9)
The Al-containing silicon material, the negative electrode, and the lithium ion secondary battery of Example 9 were manufactured in the same manner as in Example 8 except that the following annealing step was added to the step a).
　・アニール工程
　冷却されたＣａ、Ａｌ及びＳｉを含有する固体を、窒素雰囲気下、９００℃で２４時間加熱し、その後、冷却した。冷却後のＣａ、Ａｌ及びＳｉを含有する固体を、粉砕して粉末状にした後に、ｂ）工程に供した。 Annealing Step The cooled solid containing Ca, Al and Si was heated at 900 ° C. for 24 hours under a nitrogen atmosphere, and then cooled. The solid containing Ca, Al and Si after cooling was ground into a powder, and then subjected to the step b).
　（評価例６）
　評価例３と同様の方法で、実施例５～実施例９のＡｌ含有シリコン材料の元素分析を行った。これらの元素分析の結果を、質量％として、表３に示す。各実施例のＡｌ含有シリコン材料に若干量のＦｅが存在するのは、原料の金属にＦｅが不純物として含まれていたためである。また、各実施例のＡｌ含有シリコン材料に含まれているＣｌ、Ｃａ、Ｃ及びＯは、製造で使用した酸のアニオン、原料、炭素坩堝、溶媒（水）などに由来する。　 (Evaluation example 6)
Elemental analysis of the Al-containing silicon materials of Examples 5 to 9 was performed in the same manner as in Evaluation Example 3. The results of these elemental analyzes are shown in Table 3 as mass%. The reason why a small amount of Fe is present in the Al-containing silicon material of each example is that Fe is contained as an impurity in the metal of the raw material. Further, Cl, Ca, C and O contained in the Al-containing silicon material of each example are derived from the anion of the acid used in the production, the raw material, the carbon crucible, the solvent (water) and the like.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３から、ａ）工程でのＡｌの添加量が増加するに従い、Ａｌ含有シリコン材料におけるＡｌ含有量も増加するのが確認できる。ただし、ａ）工程でのＡｌの添加量の増加割合に対して、Ａｌ含有シリコン材料におけるＡｌ含有量の増加割合は、低いことがわかる。これらの結果から、ａ）工程で添加したＡｌの一部は、ｂ）工程での酸処理において、酸溶液に溶解して除去されたと考えられる。
　また、実施例８と実施例９の結果から、ａ）工程にアニール工程を加えることで、Ａｌ含有シリコン材料におけるＡｌ含有量が増加するのがわかる。アニール工程により、比較的多くのＡｌが、ＣａＳｉ２のＳｉと置換するＣａＳｉ２－ｘＡｌｘなる置換型固溶体を形成したために、ｂ）工程での酸処理において除去されるのを免れたと推察される。 From Table 3, it can be confirmed that the Al content in the Al-containing silicon material also increases as the addition amount of Al in the step a) increases. However, it is understood that the increase rate of the Al content in the Al-containing silicon material is lower than the increase rate of the addition amount of Al in the step a). From these results, it is considered that a part of Al added in the step a) was dissolved and removed in the acid solution in the acid treatment in the step b).
Further, from the results of Example 8 and Example 9, it is understood that the Al content in the Al-containing silicon material is increased by adding the annealing step to the step a). The annealing process, a relatively large amount of Al, in order to form the CaSi 2-x Al x becomes substitutional solid solution is replaced with Si of CaSi 2, is presumed to have escaped from being removed in the acid treatment in b) step Ru.
　（評価例７）
　実施例５～実施例９のリチウムイオン二次電池に対して、電流０．２ｍＡで０．０１Ｖまで放電を行い、その後、電流０．２ｍＡで１．０Ｖまで充電を行うとの初回充放電を行った。
　さらに、初回充放電後の実施例５～実施例９のリチウムイオン二次電池につき、電流０．５ｍＡで０．０１Ｖまで放電を行い、その後、電流０．５ｍＡで１．０Ｖまで充電を行うとの充放電サイクルを５０回行った。
　また、実施例５～実施例９のリチウムイオン二次電池に対して、電流０．２ｍＡで０．０１Ｖまで放電を行い、その後、電流０．２ｍＡで０．８Ｖまで充電を行うとの初回充放電を行った。 (Evaluation example 7)
The lithium ion secondary batteries of Example 5 to Example 9 were discharged to 0.01 V at a current of 0.2 mA and then charged to 1.0 V at a current of 0.2 mA. went.
Furthermore, for the lithium ion secondary batteries of Example 5 to Example 9 after the initial charge and discharge, discharging to 0.01 V with a current of 0.5 mA and then charging to 1.0 V with a current of 0.5 mA The charge and discharge cycle of 50 cycles was performed.
In addition, the lithium ion secondary batteries of Examples 5 to 9 were discharged to 0.01 V at a current of 0.2 mA, and then charged to 0.8 V at a current of 0.2 mA. Discharge was done.
　初期効率及び容量維持率を以下の各式で算出した。
　初期効率（％）＝１００×（初回充電容量）／（初回放電容量）
　容量維持率（％）＝１００×（５０サイクル時の充電容量）／（１サイクル目の充電容量）
　初回放電容量、初回充電容量（１．０Ｖ及び０．８Ｖ）、初期効率（１．０Ｖ及び０．８Ｖ）、容量維持率の結果を、Ａｌ質量％の結果とともに表４及び表５に示す。　 The initial efficiency and capacity retention rate were calculated by the following formulas.
Initial efficiency (%) = 100 × (initial charge capacity) / (initial discharge capacity)
Capacity retention rate (%) = 100 × (charge capacity at 50 cycles) / (charge capacity at first cycle)
The results of the initial discharge capacity, the initial charge capacity (1.0 V and 0.8 V), the initial efficiency (1.0 V and 0.8 V), and the capacity retention rate are shown in Tables 4 and 5 together with the results of Al mass%.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　表４から、特に、実施例７～実施例９のリチウムイオン二次電池は、優れた初回充放電容量を示したといえる。表５から、実施例５～実施例９のリチウムイオン二次電池は、同等の初期効率を示し、同等の容量維持率を示したといえる。容量維持率の観点からは、特に、実施例７～実施例９のリチウムイオン二次電池が優れているといえる。
　以上の結果から、本発明のＡｌ含有シリコン材料における、Ａｌ質量％（ＷＡｌ％）は、０．２５％以上が特に好適といえる。 From Table 4, it can be said that, particularly, the lithium ion secondary batteries of Examples 7 to 9 exhibited excellent initial charge and discharge capacities. From Table 5, it can be said that the lithium ion secondary batteries of Examples 5 to 9 exhibited equivalent initial efficiencies and equivalent capacity retention rates. From the viewpoint of the capacity retention rate, in particular, it can be said that the lithium ion secondary batteries of Examples 7 to 9 are excellent.
From the above results, it can be said that 0.25% or more of Al mass% (W Al %) in the Al-containing silicon material of the present invention is particularly preferable.
　（実施例１０）
　以下のとおり、実施例１０のＡｌ含有シリコン材料を製造した。 (Example 10)
The Al-containing silicon material of Example 10 was produced as follows.
　ａ）工程
　Ｃａ、Ａｌ及びＳｉを炭素坩堝に秤量した。Ｃａ及びＳｉの元素組成比は１：２であり、Ａｌの添加量はＣａ、Ａｌ及びＳｉの全体の質量に対して１％とした。アルゴンガス雰囲気下の高周波誘導加熱装置にて、炭素坩堝を１３００℃付近で加熱してＣａ、Ａｌ及びＳｉを含む溶湯とした。前記溶湯を所定の鋳型に注湯することで冷却して固体とした。当該固体を粉砕して粉末状にした後に、ｂ）工程に供した。 a) Step Ca, Al and Si were weighed in a carbon crucible. The elemental composition ratio of Ca and Si was 1: 2, and the amount of Al added was 1% with respect to the total mass of Ca, Al and Si. A carbon crucible was heated at around 1300 ° C. in a high frequency induction heating apparatus under an argon gas atmosphere to obtain a molten metal containing Ca, Al and Si. The molten metal is poured into a predetermined mold to cool and solidify. The solid was pulverized into a powder and then subjected to the step b).
　ｂ）工程
　窒素ガス雰囲気下にて、０℃の１７ｗｔ％塩酸に、ａ）工程で得られた粉末状の固体を加え、撹拌した。反応液を濾過し、残渣を蒸留水及びアセトンで洗浄し、さらに、室温で減圧乾燥してＡｌ含有シリコン材料の前駆体を得た。 b) Process In a nitrogen gas atmosphere, the powdery solid obtained in the process a) was added to 17 wt% hydrochloric acid at 0 ° C. and stirred. The reaction solution was filtered, and the residue was washed with distilled water and acetone, and further dried at room temperature under reduced pressure to obtain a precursor of an Al-containing silicon material.
　ｃ）工程
　Ａｌ含有シリコン材料の前駆体を、窒素ガス雰囲気下、９００℃で１時間加熱して、Ａｌ含有シリコン材料を製造した。 c) Step The precursor of the Al-containing silicon material was heated at 900 ° C. for 1 hour in a nitrogen gas atmosphere to produce an Al-containing silicon material.
　・炭素被覆工程
　ｃ）工程を経たＡｌ含有シリコン材料をロータリーキルン型の反応器に入れ、プロパン－アルゴン混合ガスの通気下にて８８０℃、滞留時間６０分間の条件で熱ＣＶＤを行い、炭素被覆されたＡｌ含有シリコン材料を得た。この炭素被覆されたＡｌ含有シリコン材料を実施例１０のＡｌ含有シリコン材料とした。 Carbon Coating Step c) The Al-containing silicon material obtained in step c) is placed in a rotary kiln type reactor, and thermal CVD is performed at 880 ° C. for 60 minutes under aeration of propane-argon mixed gas, thereby carbon coating An Al-containing silicon material was obtained. This carbon-coated Al-containing silicon material was used as the Al-containing silicon material of Example 10.
　実施例１０のＡｌ含有シリコン材料を用いて、以下のとおり、実施例１０の負極及び実施例１０のリチウムイオン二次電池を製造した。 The negative electrode of Example 10 and the lithium ion secondary battery of Example 10 were manufactured as follows using the Al-containing silicon material of Example 10.
　負極活物質として実施例１０のＡｌ含有シリコン材料８０．８質量部、導電助剤としてアセチレンブラック１０．２質量部、結着剤としてポリアミドイミド９質量部、及び、適量のＮ－メチル－２－ピロリドンを混合して、スラリーを製造した。負極用集電体として銅箔を準備した。この銅箔の表面に、ドクターブレードを用いて、上記スラリーを膜状に塗布した。スラリーが塗布された銅箔を８０℃、１５分間乾燥することで、Ｎ－メチル－２－ピロリドンを除去した。その後、プレスし、真空ポンプによる減圧雰囲気で１８０℃、３０分加熱することで、負極活物質層が形成された実施例１０の負極を製造した。 80.8 parts by mass of the Al-containing silicon material of Example 10 as a negative electrode active material, 10.2 parts by mass of acetylene black as a conduction aid, 9 parts by mass of polyamideimide as a binder, and an appropriate amount of N-methyl-2- The pyrrolidone was mixed to produce a slurry. A copper foil was prepared as a current collector for the negative electrode. The slurry was applied in the form of a film on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried at 80 ° C. for 15 minutes to remove N-methyl-2-pyrrolidone. Then, the negative electrode was pressed and heated at 180 ° C. for 30 minutes in a reduced pressure atmosphere using a vacuum pump to manufacture the negative electrode of Example 10 in which the negative electrode active material layer was formed.
　正極活物質としてＬｉＮｉ８２／１００Ｃｏ１５／１００Ａｌ３／１００Ｏ２を６９質量部、正極活物質としてＬｉＦｅＰＯ４を２６質量部、導電助剤としてアセチレンブラック２質量部、結着剤としてポリフッ化ビニリデン３質量部、及び、適量のＮ－メチル－２－ピロリドンを混合して、スラリーを製造した。正極用集電体としてアルミニウム箔を準備した。このアルミニウム箔の表面に、ドクターブレードを用いて上記スラリーが膜状になるように塗布した。スラリーが塗布されたアルミニウム箔を８０℃で２０分間乾燥することで、Ｎ－メチル－２－ピロリドンを除去した。その後、プレスし、真空ポンプによる減圧雰囲気で１２０℃、６時間加熱することで、正極活物質層が集電体の表面に形成された正極を製造した。 69 parts by mass of LiNi 82/100 Co 15/100 Al 3/100 O 2 as a positive electrode active material, 26 parts by mass of LiFePO 4 as a positive electrode active material, 2 parts by mass of acetylene black as a conduction aid, polyfluorinated as a binder A slurry was prepared by mixing 3 parts by mass of vinylidene and an appropriate amount of N-methyl-2-pyrrolidone. An aluminum foil was prepared as a positive electrode current collector. The slurry was applied in the form of a film on the surface of the aluminum foil using a doctor blade. The N-methyl-2-pyrrolidone was removed by drying the slurry-coated aluminum foil at 80 ° C. for 20 minutes. Then, the resultant was pressed and heated at 120 ° C. for 6 hours in a reduced pressure atmosphere using a vacuum pump to manufacture a positive electrode having a positive electrode active material layer formed on the surface of the current collector.
　セパレータとして、ポリエチレン製多孔質膜を準備した。また、ジメチルカーボネート及びフルオロエチレンカーボネートを体積比８１：１９で混合した混合溶媒に、ＬｉＰＦ６を濃度２ｍｏｌ／Ｌで溶解した溶液を、電解液とした。 A polyethylene porous membrane was prepared as a separator. Further, a solution in which LiPF 6 was dissolved at a concentration of 2 mol / L in a mixed solvent in which dimethyl carbonate and fluoroethylene carbonate were mixed at a volume ratio of 81:19 was used as an electrolytic solution.
　実施例１０の負極、セパレータ、正極の順に積層して、積層体とした。この積層体及び電解液をラミネートフィルム製の袋に収容して、袋を密閉し、実施例１０のリチウムイオン二次電池を製造した。 It laminated | stacked in order of the negative electrode of Example 10, the separator, and the positive electrode, and was set as the laminated body. The laminate and the electrolytic solution were housed in a laminate film bag, the bag was sealed, and the lithium ion secondary battery of Example 10 was manufactured.
　（比較例４）
　ａ）工程において、Ａｌを添加しなかったこと以外は、実施例１０と同様の方法で、比較例４の炭素被覆シリコン材料、比較例４の負極、比較例４のリチウムイオン二次電池を製造した。 (Comparative example 4)
In the step a), the carbon-coated silicon material of Comparative Example 4, the negative electrode of Comparative Example 4, and the lithium ion secondary battery of Comparative Example 4 are produced in the same manner as in Example 10 except that Al is not added. did.
　（評価例８）
　評価例３と同様の方法で、実施例１０のＡｌ含有シリコン材料及び比較例４の炭素被覆シリコン材料の元素分析を行った。これらの元素分析の結果を、質量％として、表６に示す。　 (Evaluation example 8)
Elemental analysis of the Al-containing silicon material of Example 10 and the carbon-coated silicon material of Comparative Example 4 was performed in the same manner as in Evaluation Example 3. The results of these elemental analyzes are shown in Table 6 as mass%.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　（評価例９）
　実施例１０のリチウムイオン二次電池を電圧４．１Ｖまで充電した。電圧４．１Ｖで充電状態の実施例１０のリチウムイオン二次電池を解体して、充電状態の実施例１０の負極を取り出した。取り出した負極を、ジメチルカーボネートで洗浄し、次いで乾燥した。以上の作業は、不活性ガス雰囲気下で行った。乾燥後の負極を大気下に曝した状態で、１０℃／分の昇温速度で５５０℃まで加熱して、負極の温度変化を観測した。
　比較例４のリチウムイオン二次電池についても同様の試験を行った。 (Evaluation example 9)
The lithium ion secondary battery of Example 10 was charged to a voltage of 4.1 V. The lithium ion secondary battery of Example 10 in the charged state at a voltage of 4.1 V was disassembled, and the negative electrode of Example 10 in the charged state was taken out. The removed negative electrode was washed with dimethyl carbonate and then dried. The above work was performed under an inert gas atmosphere. While the dried negative electrode was exposed to the atmosphere, it was heated to 550 ° C. at a temperature rising rate of 10 ° C./min to observe a temperature change of the negative electrode.
The same test was performed on the lithium ion secondary battery of Comparative Example 4.
　実施例１０の負極については、１０℃／分での昇温に追従する温度変化が観測された。他方、比較例４の負極については、２６３℃に達した時点で、１０℃／分での昇温から逸脱する急激な昇温が観測された。
　以上の結果から、本発明のＡｌ含有シリコン材料は、Ａｌの存在に因り、充電状態での熱安定性に優れるといえる。 For the negative electrode of Example 10, a temperature change following the temperature rise at 10 ° C./min was observed. On the other hand, for the negative electrode of Comparative Example 4, when reaching 263 ° C., a rapid temperature rise was observed that deviates from the temperature rise at 10 ° C./min.
From the above results, it can be said that the Al-containing silicon material of the present invention is excellent in thermal stability in a charged state due to the presence of Al.

Claims (8)

  1. 　Ａｌ質量％（ＷＡｌ％）が０＜ＷＡｌ＜１を満足し、Ｓｉ質量％（ＷＳｉ％）が６０≦ＷＳｉ≦９０を満足するＡｌ含有シリコン材料を含むことを特徴とする負極活物質。 An active negative electrode characterized in that it contains an Al-containing silicon material in which Al mass% (W Al %) satisfies 0 <W Al <1 and Si mass% (W Si %) satisfies 60 ≦ W Si ≦ 90. material.
  2. 　前記Ａｌ含有シリコン材料におけるＡｌ質量％（ＷＡｌ％）とＦｅ質量％（ＷＦｅ％）の関係が、ＷＡｌ＞ＷＦｅを満足する請求項１に記載の負極活物質。 The negative electrode active material according to claim 1, wherein the relationship between Al mass% (W Al %) and Fe mass% (W Fe %) in the Al-containing silicon material satisfies W Al > W 2 Fe .
  3. 　前記Ａｌ含有シリコン材料は酸素を含み、Ｏ質量％（ＷＯ％）が５≦ＷＯ≦３０を満足する請求項１又は２に記載の負極活物質。 3. The negative electrode active material according to claim 1, wherein the Al-containing silicon material contains oxygen, and O mass% (W 2 O %) satisfies 5 ≦ W 2 O ≦ 30.
  4. 　複数枚の板状シリコン体が厚さ方向に積層されてなる構造を有する請求項１～３のいずれか１項に記載の負極活物質。 The negative electrode active material according to any one of claims 1 to 3, which has a structure in which a plurality of plate-like silicon bodies are stacked in a thickness direction.
  5. 　請求項１～４のいずれか１項に記載の負極活物質を具備する負極。 A negative electrode comprising the negative electrode active material according to any one of claims 1 to 4.
  6. 　請求項１～４のいずれか１項に記載の負極活物質を具備する二次電池。 A secondary battery comprising the negative electrode active material according to any one of claims 1 to 4.
  7. 　請求項１～４のいずれか１項に記載の負極活物質の製造方法であって、
    　ａ）Ｃａ、Ａｌ及びＳｉを含む溶湯を冷却して、固体とする工程、
    　ｂ）前記固体を酸と反応させて、Ａｌ含有シリコン材料の前駆体を得る工程、
    　ｃ）前記前駆体を３００℃以上で加熱する工程、
    　を含むことを特徴とする負極活物質の製造方法。     It is a manufacturing method of the negative electrode active material of any one of Claims 1-4, Comprising:
    a) cooling the molten metal containing Ca, Al and Si to solidify it;
    b) reacting the solid with an acid to obtain a precursor of an Al-containing silicon material,
    c) heating the precursor at 300 ° C. or higher,
    A method of producing a negative electrode active material, comprising:
  8. 　前記ａ）工程が、Ｃａ、Ａｌ及びＳｉを含む溶湯を冷却して固体とする工程、及び、前記固体の固体状態を維持しつつ加熱するアニール工程を含む、請求項７に記載の負極活物質の製造方法。 The negative electrode active material according to claim 7, wherein the step a) includes a step of cooling the molten metal containing Ca, Al and Si to form a solid, and an annealing step of heating while maintaining the solid state of the solid. Manufacturing method.
PCT/JP2018/023077 2017-09-14 2018-06-18 Negative electrode active substance comprising al-containing silicon material WO2019053984A1 (en)

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WO2016031146A1 (en) * 2014-08-27 2016-03-03 株式会社豊田自動織機 Method for producing carbon-coated silicon material
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WO2015182120A1 (en) * 2014-05-29 2015-12-03 株式会社豊田自動織機 Copper-containing silicon material, method for manufacturing same, negative-electrode active substance, and secondary cell
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