WO2016043061A1 - Si-BASED ALLOY NEGATIVE ELECTRODE MATERIAL FOR ELECTRICITY STORAGE DEVICES AND ELECTRODE USING SAME - Google Patents

Si-BASED ALLOY NEGATIVE ELECTRODE MATERIAL FOR ELECTRICITY STORAGE DEVICES AND ELECTRODE USING SAME Download PDF

Info

Publication number
WO2016043061A1
WO2016043061A1 PCT/JP2015/075119 JP2015075119W WO2016043061A1 WO 2016043061 A1 WO2016043061 A1 WO 2016043061A1 JP 2015075119 W JP2015075119 W JP 2015075119W WO 2016043061 A1 WO2016043061 A1 WO 2016043061A1
Authority
WO
WIPO (PCT)
Prior art keywords
phase
negative electrode
crystallite size
electrode material
based alloy
Prior art date
Application number
PCT/JP2015/075119
Other languages
French (fr)
Japanese (ja)
Inventor
友紀 廣野
哲嗣 久世
哲朗 仮屋
澤田　俊之
Original Assignee
山陽特殊製鋼株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 山陽特殊製鋼株式会社 filed Critical 山陽特殊製鋼株式会社
Priority to KR1020177004242A priority Critical patent/KR20170057235A/en
Priority to CN201580046199.4A priority patent/CN106605322A/en
Publication of WO2016043061A1 publication Critical patent/WO2016043061A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-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
    • H01G11/04—Hybrid capacitors
    • H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-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, LIGHT-SENSITIVE OR TEMPERATURE-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
    • H01G11/32—Carbon-based
    • H01G11/38—Carbon pastes or blends; Binders or additives therein
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-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
    • H01G11/50—Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • 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
    • 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
    • Y02E60/13—Energy storage using capacitors

Definitions

  • the present invention relates to a Si-based alloy negative electrode material that is excellent in conductivity of an electricity storage device that involves movement of lithium ions during charge and discharge, such as a lithium ion secondary battery, a hybrid capacitor, and an all solid lithium ion secondary battery, and an electrode using the same Is.
  • Si is attracting attention as a material that can replace carbonaceous materials.
  • the reason is that Si forms a compound represented by Li22Si5 and can occlude a large amount of lithium, so that the capacity of the negative electrode can be greatly increased as compared with the case of using a carbonaceous material. This is because there is a possibility that the storage capacity of the lithium ion secondary battery, the hybrid capacitor, and the all solid state battery can be increased.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2001-297757
  • Patent Document 2 Japanese Patent Application Laid-Open No. 10-318044
  • an electrode in which a phase of an active material containing a Si phase is coated with a conductive material such as Cu that is not alloyed with lithium, and a manufacturing method thereof are disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-228059 (Patent Document). 3) and Japanese Patent Laid-Open No. 2005-44672 (Patent Document 4).
  • the problem to be solved by the present invention is to control the chemical composition, structure, structure size, etc. of the Si phase or intermetallic compound phase in the Si-based alloy at a high level, thereby enabling the lithium ion secondary battery or hybrid to be controlled. It is to propose a Si-based alloy negative electrode material that is excellent in charge / discharge characteristics with respect to an electricity storage device that moves lithium ions during charge / discharge, such as a capacitor and an all solid state battery.
  • the inventors have intensively developed, and as a result, refinement of the structure, excellent ion conductivity and electron conductivity, control of the component system that enhances the stress relaxation effect, Si phase and
  • the present inventors have found a Si-based alloy negative electrode material capable of obtaining excellent battery characteristics by controlling the crystallite size of the intermetallic compound phase.
  • a negative electrode material made of a Si-based alloy for an electricity storage device accompanied by movement of lithium ions during charge and discharge is Having a Si main phase composed of Si and a compound phase composed of one or more elements other than Si and Si;
  • the compound phase has a phase comprising Si and Cr, or a phase comprising Si, Cr and Ti;
  • Si crystallite size of the Si main phase is 30 nm or less,
  • the crystallite size of the compound phase comprising Si and Cr or Si, Cr and Ti is 40 nm or less,
  • the total content of Cr and Ti is 21.1 to 40 at. %
  • a negative electrode material made of a Si-based alloy having a Cr / Ti ratio of Cr% / (Cr% + Ti%) in the range of 0.15 to 1.00.
  • a negative electrode material made of a Si-based alloy for an electricity storage device that involves movement of lithium ions during charge and discharge, wherein the negative electrode material made of the Si-based alloy is a Si main phase made of Si. And a compound phase comprising one or more elements other than Si and Si, the compound phase having a phase comprising Si and Cr, or a phase comprising Si, Cr and Ti,
  • the Si crystallite size is 30 nm or less
  • the crystallite size of the compound phase composed of Si and Cr, or Si, Cr and Ti is 40 nm or less
  • the total content of Cr and Ti is 21.1 to 40 at.
  • a negative electrode material made of a Si-based alloy for an electricity storage device is provided, in which Cr% / (Cr% + Ti%), which is a ratio of Cr and Ti, is 0.15 to 1.00. .
  • Cu, V, Mn, Fe, Ni, Nb, Zn, Al are included in the compound phase of the negative electrode material made of the Si-based alloy for an electricity storage device described in the other embodiment. At least one element selected from the group consisting of a total content of 0.05 at. % To 5 at. %, A negative electrode material made of a Si-based alloy for power storage devices is provided.
  • the total content is 0.05 at. % To 5 at. %, A negative electrode material made of a Si-based alloy for power storage devices is provided.
  • a negative electrode made of an alloy is provided.
  • Cr is an essential element for generating Si 2 Cr effective for the formation of a Si phase and a fine eutectic structure.
  • Ti is substituted by Cr to increase the lattice constant of Si 2 Cr, thereby improving lithium ion conductivity. Presumed to increase.
  • the crystallite size of the Si phase is inserting the crystallite size of the Si phase to 30 nm or less and the crystallite size of the compound phase of Si and Cr or the compound phase of Si, Cr and Ti to 40 nm or less, occlusion / release of lithium to Si is performed. It plays the role of relieving the stress caused by the volume expansion at the time and preventing electrical isolation due to the pulverization of Si, and provides excellent charge / discharge cycle characteristics.
  • one or more of additive elements such as Cu, V, Mn, Fe, Ni, Nb, Pd, Zn, and Al are added to a sample made of Si and Cr, or Si and Cr and Ti, which are Si-based alloy negative electrode materials for power storage devices.
  • Si and Cr, or Si and Cr and Ti which are Si-based alloy negative electrode materials for power storage devices.
  • the compound phase surrounds the periphery of the fine Si phase, and mitigates the stress caused by the pulverization of Si and the volume expansion at the time of insertion and extraction of lithium into and from the Si. It plays a role in preventing collapse and electrical isolation of Si.
  • excellent battery characteristics are provided.
  • a sample made of Si and Cr, or Si and Cr and Ti, which are Si-based alloy negative electrode materials for electricity storage devices contains one or more additive elements such as Mg, B, P and Ga in a total of 0.05 at. % To 5 at.
  • the compound phase surrounds the periphery of the fine Si phase, and mitigates the stress caused by the pulverization of Si and the volume expansion at the time of insertion and extraction of lithium into and from the Si. It plays a role in preventing collapse and electrical isolation of Si.
  • P-type semiconductor structure by adding B it plays a role of improving the electrical conductivity of Si.
  • N-type semiconductor structure by adding P it plays a role of improving the electrical conductivity of Si.
  • excellent battery characteristics are provided.
  • Cross-sectional SEM image of the Si-Si 2 Cr eutectic alloy is a diagram showing a. XRD of Si—Si 2 Cr eutectic alloy with varying Cr / Ti ratio.
  • the present invention is described in detail below.
  • the charge / discharge capacity of a lithium ion secondary battery is determined by the amount of lithium transferred.
  • Si causes volume expansion of about 400% when lithium is occluded / released, Si is peeled off or dropped from the electrode, or Si cannot maintain contact with the current collector. A sudden drop in capacity occurs.
  • Si phase size is too large, Si does not react with lithium up to the internal Si phase, but expands from the surface layer that easily reacts with lithium of Si, cracks occur, and then the internal unreacted Si phase expands.
  • the Si is pulverized repeatedly such that cracks occur. As a result, Si peels off from the electrode, or Si cannot maintain contact with the current collector, resulting in a rapid decrease in charge / discharge capacity associated with the cycle.
  • FIG. 1 is a cross-sectional structure diagram of a Si—Si 2 Cr eutectic alloy according to the present invention, taken by a scanning electron micrograph, wherein the black phase is the Si phase and the white phase is the Si 2 Cr phase. As shown in FIG. 1, both the Si phase and the CrSi 2 phase are extremely fine. In addition, compared with other elements, such as Fe and V, the following is estimated about the cause by which Cr addition produces an extremely fine eutectic structure
  • the amount of additive element necessary to obtain the eutectic of the Si phase and silicide is determined by the type of element, for example, 26.5% for Fe and 3% for V. These can be read from the phase diagrams of Si and additive elements.
  • the amount of silicide is inevitably increased and coarsening is likely, and the proportion of the Si phase that occludes / releases Li decreases.
  • a high discharge capacity cannot be obtained.
  • the Si—Si 2 Cr eutectic alloy can have both a high discharge capacity and an excellent cycle life.
  • the charge / discharge characteristics can be further improved by replacing a part of Cr with Ti.
  • replacing Cr with Ti in the Si—Si 2 Cr eutectic alloy the inventor found that Ti was replaced with Cr in Si 2 Cr, and the lattice constant was changed without changing its crystal structure. I thought it would increase.
  • FIG. 2 is a diagram showing X-ray diffraction of a Si—Si 2 Cr eutectic alloy with a changed Cr / Ti ratio. As shown in this figure, by replacing a part of Cr with Ti, the diffraction peak position of Si 2 Cr is shifted to the lower angle side without changing the crystal structure, and the lattice constant is increased. It is considered a thing.
  • the characteristics of the lithium ion secondary battery can be further improved by controlling the crystallite size. If the Si phase size is too large, Si does not react with lithium up to the internal Si phase, but expands from the surface layer that reacts easily with lithium of Si, cracks occur, and then the internal unreacted Si phase expands, Moreover, the pulverization of Si which repeats that a crack arises is caused. As a result, Si peels off from the electrode, or Si cannot maintain contact with the current collector, resulting in a rapid decrease in charge / discharge capacity associated with the cycle.
  • the crystallite size of the Si phase of the negative electrode material for a lithium ion secondary battery it is necessary to refine the structure of the Si phase to a size at which pulverization does not occur, and it is preferable to control the crystallite size of the Si phase of the negative electrode material for a lithium ion secondary battery to 30 nm or less. More preferably, it is 25 nm or less. In particular, it is preferably 10 nm or less.
  • the crystallite size it is preferable to control the crystallite size to 40 nm or less. More preferably, it is 20 nm or less. In particular, it is preferably 10 nm or less.
  • Examples of the production method include water atomization, single-roll quenching method, twin-roll quenching method, gas atomization method, disk atomization method, and centrifugal atomization, but are not limited thereto. Further, when the cooling effect is insufficient in the above process, mechanical milling or the like can be performed. Examples of the milling method include a ball mill, a bead mill, a planetary ball mill, an attritor, and a vibration ball mill, but are not limited thereto.
  • the Si compound phase can relax the volume expansion and contraction of Si during charge and discharge, and the electrical and electronic isolation of the active material in the electrode It is possible to prevent the cycle characteristics from being significantly deteriorated. Furthermore, if the total amount of Cr and Ti is 40% or less, a reduction in the proportion of the Si phase that occludes and releases Li is prevented, and a high discharge capacity is obtained. Therefore, by making the total content of Cr and Ti 21.1 to 40%, the amount of the Si compound can be increased to increase the electron conductivity of the electrode and to suppress the stress due to the volume expansion and contraction of the Si phase during charge and discharge. It becomes possible to secure the phase.
  • the total range of Cr and Ti is preferably 22 to 35%, more preferably 23 to 30%.
  • the preferable range of Cr% / (Cr% + Ti%) is 0.15 to 0.90, more preferably 0.20 to 0.80.
  • the composition of the Six (Cr, Ti) y phase is x> It must be y.
  • a fine Si phase is obtained by forming a eutectic alloy with Si in addition to Cr and Ti, so that the intermetallic compound is more conductive and flexible than Si.
  • One or more additive elements such as Cu, V, Mn, Fe, Ni, Nb, Zn, and Al can be further included.
  • the total content of Cu, V, Mn, Fe, Ni, Nb, Pd, Zn and Al is 0.05 at. % Or more, 5 at. % Or less, the amount of the lithium inert element does not increase, and a decrease in charge / discharge capacity can be prevented. Therefore, the total content of additive elements contained at least one of Cu, V, Mn, Fe, Ni, Nb, Pd, Zn, and Al is 0.05 at. % To 5 at. % Is desirable. More preferably, 0.1 at. % To 3 at. %.
  • Co, Zr, Pd, Bi, In, Sb, Sn, and Mo aiming at the same effect are also set to 0.05 at. % To 5 at. % Is desirable.
  • the total content of Mg, B, P and Ga is 0.05 at. % Or more, 5 at. % Or less, the amount of the lithium inert element does not increase, and a decrease in charge / discharge capacity can be prevented.
  • the total content of additive elements contained at least one of Mg, B, P and Ga is 0.05 at. % To 5 at. % Is desirable. More preferably, 0.1 at. % To 3 at. %.
  • Co, Zr, Pd, Bi, In, Sb, Sn, and Mo aiming at similar effects also have a total content of at least one additive element of 0.05 at. % To 5 at. % Is desirable.
  • Negative electrode material powders for lithium ion secondary batteries having the compositions shown in Tables 1 and 2 were prepared by a single roll quenching method, a gas atomizing method, or the like described below.
  • a liquid quenching method which is a single roll quenching method
  • a raw material having a predetermined composition is placed in a quartz tube having pores at the bottom, melted at a high frequency in an Ar atmosphere to form a molten metal, and a copper roll that rotates this molten metal.
  • a quenching ribbon was prepared in which the crystallite size of the Si phase was refined by the quenching effect of the copper roll.
  • the milled ribbon is then sealed in an Ar atmosphere together with zirconia balls, SUS304 balls, or SUJ2 balls in a zirconia, SUS304, or SUJ2 pot container and milled for the purpose of processing into particles. It was.
  • a ball mill, a bead mill, a planetary ball mill, an attritor, a vibrating ball mill, and the like can be given.
  • a raw material having a predetermined composition is placed in a quartz crucible having pores at the bottom, heated and melted in a high-frequency induction melting furnace in an Ar gas atmosphere, and then subjected to gas injection in an Ar gas atmosphere and a tapping hot water. Then, gas atomized fine powder was obtained by rapid solidification.
  • a raw material having a predetermined composition is placed in a quartz crucible having pores at the bottom, heated and melted in a high-frequency induction melting furnace in an Ar gas atmosphere, and then in an Ar gas atmosphere, 40000 to 60000 r. p. m.
  • the hot water was discharged onto a rotating disk of No.
  • the produced atomized fine powder is sealed in a zirconia or SUS304 / SUJ2 pot container in an Ar atmosphere together with zirconia balls, SUS304 balls, or SUJ2 balls, and powdered by mechanical milling to control the crystallite size.
  • mechanical milling include a ball mill, a bead mill, a planetary ball mill, an attritor, and a vibrating ball mill.
  • the crystallite size of the atomized powder and the intermetallic compound using rapid solidification can be controlled by setting the milling time and the number of rotations.
  • a so-called bipolar coin-type cell using lithium metal as a counter electrode was used.
  • a negative electrode active material Si—Cr—Ti, etc.
  • a conductive material acetylene black
  • a binder material polyimide, polyvinylidene fluoride, etc.
  • a dispersion N-methylpyrrolidone
  • the solvent was evaporated by vacuum drying with a vacuum dryer, and then roll-pressed as necessary, and then punched into a shape suitable for the coin cell.
  • lithium for the counter electrode was punched into a shape suitable for the coin cell.
  • the vacuum drying of the slurry-coated electrode when the polyimide binder material was used, it was dried at a temperature of 200 ° C. or higher in order to fully exhibit the performance.
  • polyvinylidene fluoride or the like it was dried at a temperature of about 160 ° C.
  • the electrolyte used for the lithium ion battery was a 3: 7 mixed solvent of ethylene carbonate and dimethyl carbonate, LiPF 6 (lithium hexafluorophosphate) was used as the supporting electrolyte, and 1 mol was dissolved in the electrolyte. Since the electrolyte solution must be handled in an inert atmosphere with dew point control, the cells were all assembled in a glove box with an inert atmosphere. The separator was cut out in a shape suitable for a coin cell and then held in the electrolyte for several hours under reduced pressure in order to sufficiently permeate the electrolyte into the separator. Thereafter, the negative electrode punched out in the previous step, the separator, and the counter electrode lithium were combined in this order, and the inside of the battery was sufficiently filled with the electrolytic solution.
  • LiPF 6 lithium hexafluorophosphate
  • the measurement of charge capacity and discharge capacity was performed using the above-mentioned bipolar cell, at a temperature of 25 ° C., and charged at a current density of 0.50 mA / cm 2 until the same potential (0 V) as that of the metal lithium electrode. At a current value (0.50 mA / cm 2 ), discharging was performed up to 1.5 V, and this charging-discharging was defined as one cycle. The cycle life was evaluated by repeating the above measurement.
  • No. of the present invention example. 1 to 12 include the Si main phase and the phase composed of Si, Cr and Ti, the crystallite size of Si is 30 nm or less, and the crystallite size of the compound phase composed of Si, Cr and Ti satisfies the condition of 40 nm or less is doing.
  • Invention Example No. No. 4 contains Si main phase, Si, Cr, and Ti, the crystallite size of Si is 3 nm, and the condition that the crystallite size of Si is 30 nm or less is satisfied.
  • the crystallite size of the compound phase composed of Si, Cr, and Ti is 31 nm, and the condition that the crystallite size of the compound phase composed of Si, Cr, and Ti is 40 nm or less is satisfied.
  • the present invention conditions were satisfied, the initial discharge capacity was 789 mAh / g, the discharge capacity retention rate after 50 cycles was 92%, and both the charge / discharge capacity and the cycle life showed good characteristics.
  • No. of the present invention example. 13 to 18 include a Si main phase and a phase composed of Si and Cr, the crystallite size of Si is 30 nm or less, and the crystallite size of the compound phase composed of Si and Cr satisfies the condition of 40 nm or less.
  • Invention Example No. No. 14 contains a Si main phase, Si, and Cr, the Si crystallite size is 5 nm, and satisfies the condition that the Si crystallite size is 30 nm or less. And the crystallite size of the compound phase consisting of Si and Cr is 14 nm, and the crystallite size of the compound phase consisting of Si and Cr is 40 nm or less. Further, as described above, the present invention conditions were satisfied, the discharge capacity was 989 mAh / g, the discharge capacity retention rate after 50 cycles was 83%, and both the charge / discharge capacity and the cycle life showed good characteristics.
  • No. of the present invention example. 19 to 24 include a Si main phase and a phase composed of Si, Cr, and Ti.
  • the crystallite size of Si is 30 nm or less, and the crystallite size of the compound phase composed of Si, Cr, and Ti is 40 nm or less. is doing.
  • Invention Example No. No. 23 includes Si main phase, Si, Cr, and Ti, the Si crystallite size is 9 nm, and satisfies the condition that the Si crystallite size is 30 nm or less.
  • the crystallite size of the compound phase composed of Si, Cr and Ti is 15 nm, and the crystallite size of the compound phase composed of Si, Cr and Ti is 40 nm or less.
  • the discharge capacity was 674 mAh / g
  • the discharge capacity retention rate after 50 cycles was 84%
  • both the charge / discharge capacity and the cycle life showed good characteristics.
  • No. of the present invention example. 25 to 55 include a Si main phase and a phase composed of Si and Cr, or Si, Cr and Ti.
  • the Si main phase has a Si crystallite size of 30 nm or less, and is composed of Si and Cr, or Si, Cr and Ti.
  • the crystallite size of the compound phase satisfies the condition of 40 nm or less.
  • the total content of additive elements contained at least one of Cu, V, Mn, Fe, Ni, Nb, Zn and Al is 0.05 at. % To 5 at. %. Further, the total content of additive elements contained at least one or more of Mg, B, P and Ga is 0.05 at. % To 5 at. %. Including a small amount of addition of Co, Zr, Pd, Bi, In, Sb, Sn, etc. aiming at the same effect.
  • No. No. 39 contains Si main phase, Si, Cr, and Ti, the crystallite size of Si is 15 nm, and satisfies the condition that the crystallite size of Si is 30 nm or less.
  • the crystallite size of the compound phase composed of Si, Cr and Ti is 32 nm, and the crystallite size of the compound phase composed of Si, Cr and Ti is 40 nm or less.
  • 0.01 at. % Cu, 0.03 at. % V, 0.01 at. % Mn, 0.01 at. % Fe, 0.01 at. % Ni, 0.02 at. % Zn, 0.02 at. % Al is contained.
  • Comparative Example No. 49 does not contain Cr, and the total content of Cr and Ti is 21.1 to 40 at. %, And the Cr / Ti ratio Cr% / (Cr% + Ti%) is not in the range of 0.15 to 1.00, so the conditions of the present invention are not satisfied.
  • Comparative Example No. 81 the total content of Cr and Ti is 21.1 to 40 at. %, The ratio of Cr to Ti, Cr% / (Cr% + Ti%) is not in the range of 0.15 to 1.00, and does not satisfy the condition of the Si crystallite size of 30 nm or less. Therefore, the conditions of the present invention are not satisfied.
  • Comparative Example No. 106 the total content of Cr and Ti is 21.1 to 40 at.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)

Abstract

The present invention provides: an Si-based alloy negative electrode material which enables the achievement of excellent battery characteristics; and an electrode. This negative electrode material is a negative electrode material which is formed of an Si-based alloy and is for use in electricity storage devices wherein lithium ions move during charging and discharging. The negative electrode material which is formed of an Si-based alloy has an Si main phase that is composed of Si and a compound phase that is composed of Si and one or more elements other than Si. The compound phase comprises a phase containing a phase composed of Si and Cr or a phase composed of Si, Cr and Ti. The Si crystallite size in the Si main phase is 30 nm or less, and the crystallite size in the compound phase composed of Si and Cr or in the compound phase composed of Si, Cr and Ti is 40 nm or less. The total content of Cr and Ti is 21.1-40 at.%, and the ratio of Cr to Ti, specifically Cr%/(Cr% + Ti%) is within the range of 0.15-1.00.

Description

蓄電デバイス用Ｓｉ系合金負極材料およびそれを用いた電極Si-based alloy negative electrode material for power storage device and electrode using the same 関連出願の相互参照Cross-reference of related applications
　この出願は、２０１４年９月１６日に出願された日本国特許出願２０１４－１８７２３８号に基づく優先権を主張するものであり、これらの全体の開示内容が参照により本明細書に組み込まれる。 This application claims priority based on Japanese Patent Application No. 2014-187238 filed on Sep. 16, 2014, the entire disclosure of which is incorporated herein by reference.
　本発明は、リチウムイオン二次電池やハイブリットキャパシタ、全固体リチウムイオン二次電池など、充放電時にリチウムイオンの移動を伴う蓄電デバイスの導電性に優れるＳｉ系合金負極材料およびそれを用いた電極に関するものである。 The present invention relates to a Si-based alloy negative electrode material that is excellent in conductivity of an electricity storage device that involves movement of lithium ions during charge and discharge, such as a lithium ion secondary battery, a hybrid capacitor, and an all solid lithium ion secondary battery, and an electrode using the same Is.
　近年、携帯機器の普及に伴い、リチウムイオン電池を中心とした高性能二次電池の開発が盛んに行われている。さらに、自動車用や家庭用定置用蓄電デバイスとしてリチウムイオン二次電池やその反応機構を負極に適用したハイブリットキャパシタの開発も盛んになっている。それらの蓄電デバイスの負極材料としては、リチウムイオンを吸蔵及び放出することができる、天然黒鉛や人造黒鉛、コークスなどの炭素質材料が用いられている。しかし、これらの炭素質材料はリチウムイオンを炭素面間に挿入するため、負極に用いた際の理論容量は３７２ｍＡｈ／ｇが限界である。このことから、高容量化を目的とした炭素質材料に代わる新規材料の探索が盛んに行われている。 In recent years, with the widespread use of portable devices, development of high-performance secondary batteries centering on lithium-ion batteries has been actively conducted. Furthermore, lithium-ion secondary batteries and hybrid capacitors using the reaction mechanism of the lithium ion secondary battery as a negative electrode as active storage devices for automobiles and households have been actively developed. As a negative electrode material for these electricity storage devices, carbonaceous materials such as natural graphite, artificial graphite, and coke that can occlude and release lithium ions are used. However, since these carbonaceous materials insert lithium ions between the carbon surfaces, the theoretical capacity when used for the negative electrode is limited to 372 mAh / g. For this reason, search for new materials to replace carbonaceous materials for the purpose of increasing the capacity has been actively conducted.
　一方、炭素質材料に代わる材料として、Ｓｉが注目されている。その理由は、ＳｉはＬｉ２２Ｓｉ５で表される化合物を形成して、大量のリチウムを吸蔵することができるため、炭素質材料を使用した場合に比較して負極の容量を大幅に増大でき、結果としてリチウムイオン二次電池やハイブリットキャパシタ、全固体電池の蓄電容量を増大することができる可能性を持っているためである。 On the other hand, Si is attracting attention as a material that can replace carbonaceous materials. The reason is that Si forms a compound represented by Li22Si5 and can occlude a large amount of lithium, so that the capacity of the negative electrode can be greatly increased as compared with the case of using a carbonaceous material. This is because there is a possibility that the storage capacity of the lithium ion secondary battery, the hybrid capacitor, and the all solid state battery can be increased.
　しかし、Ｓｉを単独で負極材として使用した場合には、充電時にリチウムと合金化する際の膨張と、放電時にリチウムと脱合金化する際の収縮との繰返しによって、Ｓｉ相が微粉化されて、使用中に電極基板からＳｉ相が脱落したり、Ｓｉ相間の電気伝導性が取れなくなるなどの不具合が生じるために、蓄電デバイスとしての寿命が極めて短いといった課題があった。 However, when Si is used alone as a negative electrode material, the Si phase is pulverized by repetition of expansion when alloying with lithium during charging and contraction when dealloying with lithium during discharging. There is a problem that the life as an electricity storage device is extremely short because problems such as the Si phase dropping off from the electrode substrate during use or the electrical conductivity between the Si phases being lost can occur.
　また、Ｓｉは炭素質材料や金属系材料に比べて電気伝導性が悪く、充放電に伴う電子の効率的な移動が制限されているため、負極材としては炭素質材料など導電性を補う材料と組合せて使用される。しかし、その場合でも特に初期の充放電や高効率での充放電特性も課題となっている。 In addition, Si has poor electrical conductivity compared to carbonaceous materials and metal-based materials, and the efficient movement of electrons associated with charge / discharge is limited. Therefore, as a negative electrode material, a material that supplements conductivity, such as a carbonaceous material. Used in combination with. However, even in that case, particularly initial charge / discharge and charge / discharge characteristics with high efficiency are also problems.
　このようなＳｉ相を負極として利用する際の欠点を解決する方法として、Ｓｉなどの親リチウム相の少なくとも一部を、Ｓｉと遷移金属に代表される金属との金属間化合物で包囲した材料やその製造方法が、例えば、特開２００１－２９７７５７号公報（特許文献１）や特開平１０－３１２８０４号公報（特許文献２）に提案されている。 As a method for solving the drawbacks of using such a Si phase as a negative electrode, a material in which at least part of a parent lithium phase such as Si is surrounded by an intermetallic compound of Si and a metal typified by a transition metal, The manufacturing method is proposed in, for example, Japanese Patent Application Laid-Open No. 2001-297757 (Patent Document 1) and Japanese Patent Application Laid-Open No. 10-318044 (Patent Document 2).
　また、別の解決方法として、Ｓｉ相を含む活物質の相をリチウムと合金化しないＣｕなどの導電性材料で被覆した電極やその製造方法が、例えば、特開２００４－２２８０５９号公報（特許文献３）や特開２００５－４４６７２号公報（特許文献４）に提案されている。 As another solution, an electrode in which a phase of an active material containing a Si phase is coated with a conductive material such as Cu that is not alloyed with lithium, and a manufacturing method thereof are disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-228059 (Patent Document). 3) and Japanese Patent Laid-Open No. 2005-44672 (Patent Document 4).
特開２００１－２９７７５７号公報JP 2001-297757 A 特開平１０－３１２８０４号公報JP 10-31804 A 特開２００４－２２８０５９号公報JP 2004-228059 A 特開２００５－４４６７２号公報JP 2005-44672 A
　しかしながら、上述した活物質の相をＣｕなどの導電性材料で被覆する方法では、Ｓｉ相を含む活物質を電極に形成する工程の前または後に、Ｃｕめっきなどの方法で被覆する必要があり、また、被覆膜厚の制御など工業的に手間がかかるという問題がある。また、Ｓｉなどの親リチウム相の少なくとも一部を金属間化合物で包囲した材料は、溶融後の凝固プロセス中に親リチウム相と金属間化合物が形成されるため、工業的に好ましいプロセスといえるが、それだけでは十分な充放電サイクル特性が得られないといった問題がある。 However, in the above-described method of coating the active material phase with a conductive material such as Cu, it is necessary to coat the active material containing the Si phase with a method such as Cu plating before or after the step of forming the active material on the electrode. Further, there is a problem that it takes time and labor from the industrial point of view, such as control of the coating thickness. A material in which at least a part of a parent lithium phase such as Si is surrounded by an intermetallic compound is an industrially preferable process because a parent lithium phase and an intermetallic compound are formed during the solidification process after melting. , There is a problem that sufficient charge / discharge cycle characteristics cannot be obtained.
　そこで、本発明が解決しようとする課題は、Ｓｉ系合金中のＳｉ相や金属間化合物相の化学組成、構造、組織の大きさ等を高位に制御することで、リチウムイオン二次電池やハイブリットキャパシタ、全固体電池など、充放電時にリチウムイオンの移動を伴う蓄電デバイスに関し、充放電特性に優れるＳｉ系合金負極材料を提案することである。 Therefore, the problem to be solved by the present invention is to control the chemical composition, structure, structure size, etc. of the Si phase or intermetallic compound phase in the Si-based alloy at a high level, thereby enabling the lithium ion secondary battery or hybrid to be controlled. It is to propose a Si-based alloy negative electrode material that is excellent in charge / discharge characteristics with respect to an electricity storage device that moves lithium ions during charge / discharge, such as a capacitor and an all solid state battery.
　上述のような問題を解消するために、発明者らは鋭意開発を進めた結果、組織の微細化、優れたイオン伝導性と電子伝導性、応力緩和効果を高める成分系の制御とＳｉ相や金属間化合物相の結晶子サイズを制御することで、優れた電池特性が得られるＳｉ系合金負極材料を見出した。 In order to solve the problems as described above, the inventors have intensively developed, and as a result, refinement of the structure, excellent ion conductivity and electron conductivity, control of the component system that enhances the stress relaxation effect, Si phase and The present inventors have found a Si-based alloy negative electrode material capable of obtaining excellent battery characteristics by controlling the crystallite size of the intermetallic compound phase.
　本発明の一態様によれば、
　充放電時にリチウムイオンの移動が伴う蓄電デバイス用のＳｉ系合金からなる負極材料であって、
　前記Ｓｉ系合金からなる負極材料が、
　ＳｉからなるＳｉ主要相と
　ＳｉとＳｉ以外の一種以上の元素からなる化合物相と
を有し、
　前記化合物相が、ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる相を含んでなる相を有し、
　前記Ｓｉ主要相のＳｉ結晶子サイズが３０ｎｍ以下であり、
　ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる前記化合物相の結晶子サイズが４０ｎｍ以下であり、
　ＣｒとＴｉの合計含有量が２１．１～４０ａｔ．％であり、かつ、
　ＣｒとＴｉの比率であるＣｒ％／（Ｃｒ％＋Ｔｉ％）が０．１５～１．００の範囲である、Ｓｉ系合金からなる負極材料が提供される。 According to one aspect of the invention,
A negative electrode material made of a Si-based alloy for an electricity storage device accompanied by movement of lithium ions during charge and discharge,
The negative electrode material made of the Si-based alloy is
Having a Si main phase composed of Si and a compound phase composed of one or more elements other than Si and Si;
The compound phase has a phase comprising Si and Cr, or a phase comprising Si, Cr and Ti;
Si crystallite size of the Si main phase is 30 nm or less,
The crystallite size of the compound phase comprising Si and Cr or Si, Cr and Ti is 40 nm or less,
The total content of Cr and Ti is 21.1 to 40 at. %, And
Provided is a negative electrode material made of a Si-based alloy having a Cr / Ti ratio of Cr% / (Cr% + Ti%) in the range of 0.15 to 1.00.
　本発明の他の一態様によれば、充放電時にリチウムイオンの移動が伴う蓄電デバイス用Ｓｉ系合金からなる負極材料であって、前記Ｓｉ系合金からなる負極材料が、ＳｉからなるＳｉ主要相とＳｉとＳｉ以外の一種以上の元素からなる化合物相を有し、前記化合物相が、ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる相を含んでなる相を有し、前記Ｓｉ主要相のＳｉ結晶子サイズが３０ｎｍ以下であり、かつ、ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる化合物相の結晶子サイズが４０ｎｍ以下であること、ＣｒとＴｉの合計含有量が２１．１～４０ａｔ．％含み、ＣｒとＴｉの比率であるＣｒ％／（Ｃｒ％＋Ｔｉ％）が０．１５～１．００の範囲であることを特徴とする蓄電デバイス用Ｓｉ系合金からなる負極材料が提供される。 According to another aspect of the present invention, a negative electrode material made of a Si-based alloy for an electricity storage device that involves movement of lithium ions during charge and discharge, wherein the negative electrode material made of the Si-based alloy is a Si main phase made of Si. And a compound phase comprising one or more elements other than Si and Si, the compound phase having a phase comprising Si and Cr, or a phase comprising Si, Cr and Ti, The Si crystallite size is 30 nm or less, the crystallite size of the compound phase composed of Si and Cr, or Si, Cr and Ti is 40 nm or less, and the total content of Cr and Ti is 21.1 to 40 at. . A negative electrode material made of a Si-based alloy for an electricity storage device is provided, in which Cr% / (Cr% + Ti%), which is a ratio of Cr and Ti, is 0.15 to 1.00. .
　本発明の他の好ましい態様によれば、上記他の一態様に記載した蓄電デバイス用Ｓｉ系合金からなる負極材料の前記化合物相に、Ｃｕ、Ｖ、Ｍｎ、Ｆｅ、Ｎｉ、Ｎｂ、Ｚｎ、Ａｌからなる群から選択される少なくとも一種以上の元素を含み、合計含有量が０．０５ａｔ．％～５ａｔ．％であることを特徴とする蓄電デバイス用Ｓｉ系合金からなる負極材料が提供される。 According to another preferred embodiment of the present invention, Cu, V, Mn, Fe, Ni, Nb, Zn, Al are included in the compound phase of the negative electrode material made of the Si-based alloy for an electricity storage device described in the other embodiment. At least one element selected from the group consisting of a total content of 0.05 at. % To 5 at. %, A negative electrode material made of a Si-based alloy for power storage devices is provided.
　発明の他の好ましい態様によれば、上記態様のいずれかに記載した蓄電デバイス用Ｓｉ系合金からなる負極材料の前記化合物相に、Ｍｇ、Ｂ、Ｐ、Ｇａからなる群から選択される少なくとも一種以上の元素を含み、合計含有量が０．０５ａｔ．％～５ａｔ．％であることを特徴とする蓄電デバイス用Ｓｉ系合金からなる負極材料が提供される。 According to another preferred aspect of the invention, at least one selected from the group consisting of Mg, B, P, and Ga in the compound phase of the negative electrode material comprising the Si-based alloy for an electricity storage device described in any of the above aspects. The total content is 0.05 at. % To 5 at. %, A negative electrode material made of a Si-based alloy for power storage devices is provided.
　発明のさらに他の一態様によれば、上記態様のいずれかに記載した蓄電デバイス用Ｓｉ系合金からなる負極材料を用いた電極において、特にポリイミド系バインダーを含むことを特徴とする蓄電デバイス用Ｓｉ系合金からなる負極が提供される。 According to yet another aspect of the invention, an electrode using a negative electrode material made of a Si-based alloy for an electricity storage device according to any of the above aspects, particularly comprising a polyimide binder, Si for an electricity storage device A negative electrode made of an alloy is provided.
　本発明合金においてＣｒはＳｉ相と微細共晶組織の形成に有効なＳｉ2 Ｃｒを生成する必須元素であり、ＴｉはＣｒに置換しＳｉ2 Ｃｒの格子定数を増加させ、リチウムイオン伝導性を高めると推測される。さらに、Ｓｉ相の結晶子サイズを３０ｎｍ以下に、またＳｉとＣｒの化合物相もしくはＳｉとＣｒとＴｉの化合物相の結晶子サイズを、４０ｎｍ以下とすることで、Ｓｉへのリチウムの吸蔵・放出時の体積膨張により生じる応力の緩和、およびＳｉの微粉化による電気的孤立を防ぐ役割を果たし、優れた充放電サイクル特性が得られる。 In the alloy of the present invention, Cr is an essential element for generating Si 2 Cr effective for the formation of a Si phase and a fine eutectic structure. Ti is substituted by Cr to increase the lattice constant of Si 2 Cr, thereby improving lithium ion conductivity. Presumed to increase. Furthermore, by inserting the crystallite size of the Si phase to 30 nm or less and the crystallite size of the compound phase of Si and Cr or the compound phase of Si, Cr and Ti to 40 nm or less, occlusion / release of lithium to Si is performed. It plays the role of relieving the stress caused by the volume expansion at the time and preventing electrical isolation due to the pulverization of Si, and provides excellent charge / discharge cycle characteristics.
　また、前記蓄電デバイス用Ｓｉ系合金負極材料の化学成分の制御することで、優れた充放電サイクル特性が得られる。ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる相のＣｒとＴｉを合計で２１．１～４０ａｔ．％含み、Ｃｒ％／（Ｃｒ％＋Ｔｉ％）を０．１５～１．００の範囲に制御した場合に、その効果が大きい。 Further, by controlling the chemical component of the Si-based alloy negative electrode material for an electricity storage device, excellent charge / discharge cycle characteristics can be obtained. A total of 21.1 to 40 at.s of Cr and Ti of a phase composed of Si and Cr or Si, Cr and Ti. %, And Cr% / (Cr% + Ti%) is controlled within the range of 0.15 to 1.00.
　また、蓄電デバイス用Ｓｉ系合金負極材料のＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる試料にＣｕ、Ｖ、Ｍｎ、Ｆｅ、Ｎｉ、Ｎｂ、Ｐｄ、ＺｎおよびＡｌといった添加元素の一種以上を、合計で０．０５ａｔ．％～５ａｔ．％含有し、結晶子サイズを制御することで、化合物相が微細Ｓｉ相の周囲を取り囲み、Ｓｉの微粉化、Ｓｉへのリチウムの吸蔵・放出時の体積膨張により生じる応力を緩和し、電極の崩壊、Ｓｉの電気的孤立を防ぐ役割を果たす。これらの蓄電デバイス用Ｓｉ系合金負極材料を用いた電極において、特に結合力の高いポリイミドバインダーを含んだ場合、優れた電池特性が提供される。 In addition, one or more of additive elements such as Cu, V, Mn, Fe, Ni, Nb, Pd, Zn, and Al are added to a sample made of Si and Cr, or Si and Cr and Ti, which are Si-based alloy negative electrode materials for power storage devices. In total 0.05 at. % To 5 at. By controlling the crystallite size, the compound phase surrounds the periphery of the fine Si phase, and mitigates the stress caused by the pulverization of Si and the volume expansion at the time of insertion and extraction of lithium into and from the Si. It plays a role in preventing collapse and electrical isolation of Si. In an electrode using these Si-based alloy negative electrode materials for electricity storage devices, particularly when a polyimide binder having a high binding force is included, excellent battery characteristics are provided.
　また、蓄電デバイス用Ｓｉ系合金負極材料のＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる試料に、Ｍｇ、Ｂ、ＰおよびＧａといった添加元素を一種以上、合計で０．０５ａｔ．％～５ａｔ．％含有し、結晶子サイズを制御することで、化合物相が微細Ｓｉ相の周囲を取り囲み、Ｓｉの微粉化、Ｓｉへのリチウムの吸蔵・放出時の体積膨張により生じる応力を緩和し、電極の崩壊、およびＳｉの電気的孤立を防ぐ役割を果たす。また、Ｂ添加によるＰ型半導体構造をとることで、Ｓｉの電気伝導性の向上の役割を果たす。Ｐ添加によるＮ型半導体構造をとることで、Ｓｉの電気伝導性の向上の役割を果たす。これらの蓄電デバイス用Ｓｉ系合金負極材料を用いた電極において、特に結合力の高いポリイミドバインダーを含んだ場合、優れた電池特性が提供される。 Further, a sample made of Si and Cr, or Si and Cr and Ti, which are Si-based alloy negative electrode materials for electricity storage devices, contains one or more additive elements such as Mg, B, P and Ga in a total of 0.05 at. % To 5 at. By controlling the crystallite size, the compound phase surrounds the periphery of the fine Si phase, and mitigates the stress caused by the pulverization of Si and the volume expansion at the time of insertion and extraction of lithium into and from the Si. It plays a role in preventing collapse and electrical isolation of Si. Also, by taking a P-type semiconductor structure by adding B, it plays a role of improving the electrical conductivity of Si. By taking an N-type semiconductor structure by adding P, it plays a role of improving the electrical conductivity of Si. In an electrode using these Si-based alloy negative electrode materials for electricity storage devices, particularly when a polyimide binder having a high binding force is included, excellent battery characteristics are provided.
　以上述べたように、本発明は高容量かつ繰り返し充放電時のサイクル特性に優れた蓄電デバイス用Ｓｉ系合金負極材料を提供できる極めて優れた効果を奏するものである。 As described above, the present invention has an excellent effect of providing a Si-based alloy negative electrode material for an electricity storage device having a high capacity and excellent cycle characteristics during repeated charge and discharge.
Ｓｉ－Ｓｉ2 Ｃｒ共晶合金の断面のＳＥＭ画像を示す図である。Cross-sectional SEM image of the Si-Si 2 Cr eutectic alloy is a diagram showing a. Ｃｒ／Ｔｉ比を変化させたＳｉ－Ｓｉ2 Ｃｒ共晶合金のＸＲＤである。XRD of Si—Si 2 Cr eutectic alloy with varying Cr / Ti ratio.
　以下に、本発明について詳細に説明する。
　リチウムイオン二次電池の充放電容量はリチウムの移動量で決まってくる。リチウムを多量に吸蔵・放出できる物質が求められている。そこで、負極材料にはリチウム金属を使用すれば一番効率が良いのだが、充放電に伴うデンドライドの形成により引き起こされる電池の発火など安全性に問題がある。そこで、現在はリチウムをより多く吸蔵・放出できる合金の研究が進んでおり、それら合金の中でもＳｉは多量にリチウムを吸蔵・放出できる物質として有望視されている。そのため、合金相の主要相としてＳｉを採用する。 The present invention is described in detail below.
The charge / discharge capacity of a lithium ion secondary battery is determined by the amount of lithium transferred. There is a need for a material that can occlude and release large amounts of lithium. Therefore, although lithium metal is most effective when used as the negative electrode material, there are safety problems such as battery ignition caused by the formation of dendrites during charging and discharging. Therefore, studies on alloys that can occlude and release more lithium are currently underway, and among these alloys, Si is promising as a substance that can occlude and release lithium in large quantities. Therefore, Si is adopted as the main phase of the alloy phase.
　しかし、Ｓｉはリチウムの吸蔵・放出時に約４００％もの体積膨張を引き起こすため、電極からＳｉが剥離・脱落したり、Ｓｉが集電体との接触を保てなくなることで、サイクルに伴う充放電容量の急激な低下が起こる。また、ＳｉはＳｉ相サイズが大きすぎると、内部のＳｉ相までリチウムと反応せずに、Ｓｉのリチウムと反応しやすい表層から膨張し、亀裂が生じ、次に内部の未反応Ｓｉ相が膨張し、また亀裂が生じるといったことを繰り返すＳｉの微粉化が引き起こされる。これにより、電極からＳｉが剥離・脱落したり、Ｓｉが集電体との接触を保てなくなることで、サイクルに伴う充放電容量の急激な低下が起こる。 However, since Si causes volume expansion of about 400% when lithium is occluded / released, Si is peeled off or dropped from the electrode, or Si cannot maintain contact with the current collector. A sudden drop in capacity occurs. Also, if the Si phase size is too large, Si does not react with lithium up to the internal Si phase, but expands from the surface layer that easily reacts with lithium of Si, cracks occur, and then the internal unreacted Si phase expands. In addition, the Si is pulverized repeatedly such that cracks occur. As a result, Si peels off from the electrode, or Si cannot maintain contact with the current collector, resulting in a rapid decrease in charge / discharge capacity associated with the cycle.
　本発明における特徴は、共晶合金を得るための添加元素としてＣｒを用いたことである。図１は、本発明に係るＳｉ－Ｓｉ2 Ｃｒの共晶合金の走査型電子顕微鏡写真による断面組織図で、黒い相がＳｉ相、白い相がＳｉ2 Ｃｒ相である。この図１に示す通り、Ｓｉ相およびＣｒＳｉ2 相ともに極めて微細である。なお、ＦｅやＶなど他の元素と比較し、Ｃｒ添加が極端に微細な共晶組織をもたらし、充放電特性にも優れる原因については、以下のことが推測される。 A feature of the present invention is that Cr is used as an additive element for obtaining a eutectic alloy. FIG. 1 is a cross-sectional structure diagram of a Si—Si 2 Cr eutectic alloy according to the present invention, taken by a scanning electron micrograph, wherein the black phase is the Si phase and the white phase is the Si 2 Cr phase. As shown in FIG. 1, both the Si phase and the CrSi 2 phase are extremely fine. In addition, compared with other elements, such as Fe and V, the following is estimated about the cause by which Cr addition produces an extremely fine eutectic structure | tissue and is excellent also in a charge / discharge characteristic.
　Ｓｉ相と珪化物の共晶を得るために必要な添加元素量は元素の種類により決まっており、例えばＦｅの場合は２６．５％、Ｖの場合は３％の添加が必要である。なお、これらはいずれもＳｉと添加元素の状態図から読み取ることができる。ここで、共晶を得るためにＦｅのように比較的多くの添加量が必要な場合は必然的に珪化物の量が多くなり粗大化しやすく、Ｌｉを吸蔵・放出するＳｉ相の割合が低下し、高い放電容量が得られない。 The amount of additive element necessary to obtain the eutectic of the Si phase and silicide is determined by the type of element, for example, 26.5% for Fe and 3% for V. These can be read from the phase diagrams of Si and additive elements. Here, when a relatively large amount of addition is required, such as Fe, in order to obtain a eutectic, the amount of silicide is inevitably increased and coarsening is likely, and the proportion of the Si phase that occludes / releases Li decreases. However, a high discharge capacity cannot be obtained.
　一方、Ｖのように極端に少ない添加量で共晶となる場合、共晶組織中の珪化物の割合が少なく、必然的にＳｉ相が粗大化しやすくなり、充放電時のＳｉ相の体積変化を制御する珪化物の効果が得られない。一方、Ｃｒは共晶となる添加量がこれらの中間であり、Ｓｉ相および珪化物の両者が微細になると考えられる。したがって、Ｓｉ－Ｓｉ2 Ｃｒ共晶合金は高い放電容量と優れたサイクル寿命を兼備することができる。 On the other hand, when it becomes eutectic with an extremely small addition amount like V, the proportion of silicide in the eutectic structure is small, and the Si phase tends to be coarsened, and the volume change of the Si phase during charge / discharge The effect of the silicide to control is not obtained. On the other hand, Cr is added in the middle amount of eutectic, and it is considered that both the Si phase and the silicide become fine. Therefore, the Si—Si 2 Cr eutectic alloy can have both a high discharge capacity and an excellent cycle life.
　また、Ｃｒの一部をＴｉで置換することにより、さらに、充放電特性を改善できる。発明者は、Ｓｉ－Ｓｉ2 Ｃｒ共晶合金において、ＣｒをＴｉに置換する検討を詳細に行った結果、ＴｉはＳｉ2 ＣｒのＣｒに置換され、その結晶構造を変化させることなく格子定数を増加させると考えた。 Moreover, the charge / discharge characteristics can be further improved by replacing a part of Cr with Ti. As a result of detailed examination of replacing Cr with Ti in the Si—Si 2 Cr eutectic alloy, the inventor found that Ti was replaced with Cr in Si 2 Cr, and the lattice constant was changed without changing its crystal structure. I thought it would increase.
　図２は、Ｃｒ／Ｔｉ比を変化させたＳｉ－Ｓｉ2 Ｃｒ共晶合金のＸ線回折を示す図である。この図に示すように、Ｃｒの一部をＴｉに置換することにより、Ｓｉ2 Ｃｒは結晶構造を変化させることなく回折ピーク位置が低角度側にシフトしており、格子定数が増加しているものと考えられる。 FIG. 2 is a diagram showing X-ray diffraction of a Si—Si 2 Cr eutectic alloy with a changed Cr / Ti ratio. As shown in this figure, by replacing a part of Cr with Ti, the diffraction peak position of Si 2 Cr is shifted to the lower angle side without changing the crystal structure, and the lattice constant is increased. It is considered a thing.
　本発明におけるＣｒへのＴｉ置換によるＳｉ2 Ｃｒの格子定数増加は、珪化物中のＬｉの通過をスムーズにし、これに伴う体積変化を軽減する役割を果たしている可能性が推測される。このように、Ｓｉと珪化物の共晶系合金をリチウムイオン電池負極活物質に利用する検討で、珪化物の構造にまで踏み込んだ研究はこれまでにほとんど見られない。 The increase in the lattice constant of Si 2 Cr due to Ti substitution into Cr in the present invention is presumed to play a role of smoothing the passage of Li in the silicide and reducing the volume change associated therewith. Thus, in the study of utilizing a eutectic alloy of Si and silicide as a negative electrode active material for a lithium ion battery, there has been almost no research so far that has gone into the structure of silicide.
　上記ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉの共晶組織に加えて、結晶子サイズを制御することで、さらにリチウムイオン二次電池特性の改善が見込まれる。ＳｉはＳｉ相サイズが大きすぎると、内部のＳｉ相までリチウムと反応せずに、Ｓｉのリチウムと反応しやすい表層から膨張し、亀裂が生じ、次に内部の未反応Ｓｉ相が膨張し、また亀裂が生じるといったことを繰り返すＳｉの微粉化が引き起こされる。これにより、電極からＳｉが剥離・脱落したり、Ｓｉが集電体との接触を保てなくなることで、サイクルに伴う充放電容量の急激な低下が起こる。このことから、微粉化が起こらないサイズまでＳｉ相の組織を微細にする必要があり、前記リチウムイオン二次電池用負極材料のＳｉ相の結晶子サイズを３０ｎｍ以下に制御するのが好ましい。より好ましくは、２５ｎｍ以下であることが望ましい。特に、好ましくは１０ｎｍ以下であることが望ましい。 In addition to the eutectic structure of Si and Cr or Si, Cr and Ti, the characteristics of the lithium ion secondary battery can be further improved by controlling the crystallite size. If the Si phase size is too large, Si does not react with lithium up to the internal Si phase, but expands from the surface layer that reacts easily with lithium of Si, cracks occur, and then the internal unreacted Si phase expands, Moreover, the pulverization of Si which repeats that a crack arises is caused. As a result, Si peels off from the electrode, or Si cannot maintain contact with the current collector, resulting in a rapid decrease in charge / discharge capacity associated with the cycle. For this reason, it is necessary to refine the structure of the Si phase to a size at which pulverization does not occur, and it is preferable to control the crystallite size of the Si phase of the negative electrode material for a lithium ion secondary battery to 30 nm or less. More preferably, it is 25 nm or less. In particular, it is preferably 10 nm or less.
　Ｓｉ相の結晶子サイズの制御については、上記に定めた成分の制御に加えて、原料粉末を溶解した後の凝固時の冷却速度の制御によって可能である。製造方法としては、水アトマイズ、単ロール急冷法、双ロール急冷法、ガスアトマイズ法、ディスクアトマイズ法、遠心アトマイズ等があるが、この限りではない。また、上記プロセスで冷却効果が不十分な場合、メカニカルミリング等を行うことも可能である。ミリング方法としては、ボールミル、ビーズミル、遊星ボールミル、アトライタ、振動ボールミル等があるが、この限りではない。 The crystallite size of the Si phase can be controlled by controlling the cooling rate during solidification after dissolving the raw material powder in addition to the control of the components defined above. Examples of the production method include water atomization, single-roll quenching method, twin-roll quenching method, gas atomization method, disk atomization method, and centrifugal atomization, but are not limited thereto. Further, when the cooling effect is insufficient in the above process, mechanical milling or the like can be performed. Examples of the milling method include a ball mill, a bead mill, a planetary ball mill, an attritor, and a vibration ball mill, but are not limited thereto.
　また、Ｓｉ主要相のＳｉ結晶子サイズは、透過型電子顕微鏡（ＴＥＭ）により直接観察できる。または、粉末Ｘ線回折を用いることによって確認することができる。Ｘ線源として波長１．５４０５９ÅのＣｕＫα線を用い、２θ＝２０度～８０度の範囲で測定を行う。得られる回折スペクトルにおいては、結晶子サイズが小さくなるにつれて、比較的ブロードな回折ピークが観測される。粉末Ｘ線回折分析で得られるピークの半値幅から、Ｓｃｈｅｒｒｅｒの式を用いて求めることができる（Ｄ（Å）＝（Ｋ×λ）／（β×ｃｏｓθ）Ｄ：結晶子の大きさ、Ｋ：Ｓｃｈｅｒｒｅｒの定数、λ：使用X線管球の波長、β：結晶子の大きさによる回折線の拡がり、θ：回折角）。 Also, the Si crystallite size of the Si main phase can be directly observed with a transmission electron microscope (TEM). Alternatively, it can be confirmed by using powder X-ray diffraction. A CuKα ray having a wavelength of 1.54059 mm is used as an X-ray source, and measurement is performed in the range of 2θ = 20 degrees to 80 degrees. In the obtained diffraction spectrum, a relatively broad diffraction peak is observed as the crystallite size decreases. From the full width at half maximum of the peak obtained by powder X-ray diffraction analysis, it can be determined using the Scherrer equation (D (Å) = (K × λ) / (β × cos θ) D: crystallite size, K : Scherrer's constant, λ: wavelength of X-ray tube used, β: broadening of diffraction line depending on crystallite size, θ: diffraction angle).
　結晶子サイズにおいて、Ｓｉ主要相のみならず、金属間化合物相の結晶子サイズも重要になる。ＳｉとＣｒ、ＳｉとＣｒとＴｉ等の金属間化合物の結晶子サイズを小さくすることで、金属間化合物の降伏応力を高めることや延性、靭性の向上が期待ができるため、膨張等の影響を受けた際に、亀裂の発生等を抑制し、良好なイオン伝導性、電子伝導性を確保できる。また、金属間化合物の結晶子サイズが小さくなることで大きな粒子よりもＳｉ相とより大きな比表面積で接触し、Ｓｉ相の体積膨張収縮による応力を効率良く吸収・緩和することが可能になる。さらに、Ｓｉ相とより大きな比表面積で接触することで、リチウムイオン伝導性や電子伝導性パスが増え、よりスムーズな充放電反応を行うことが期待される。そのため、結晶子サイズを４０ｎｍ以下に制御するのが好ましい。より好ましくは、２０ｎｍ以下であることが望ましい。特に、好ましくは１０ｎｍ以下であることが望ましい。 In the crystallite size, not only the Si main phase but also the crystallite size of the intermetallic compound phase is important. By reducing the crystallite size of intermetallic compounds such as Si and Cr, Si and Cr and Ti, it is possible to increase the yield stress of the intermetallic compounds and improve ductility and toughness. When it is received, the occurrence of cracks and the like can be suppressed, and good ion conductivity and electron conductivity can be secured. Further, since the crystallite size of the intermetallic compound is reduced, it is possible to contact the Si phase with a larger specific surface area than to the larger particles, and to efficiently absorb and relax the stress due to the volume expansion and contraction of the Si phase. Furthermore, contact with the Si phase with a larger specific surface area is expected to increase the lithium ion conductivity and the electron conductivity path, and to perform a smoother charge / discharge reaction. Therefore, it is preferable to control the crystallite size to 40 nm or less. More preferably, it is 20 nm or less. In particular, it is preferably 10 nm or less.
　金属間化合物の結晶子サイズも、透過型電子顕微鏡（ＴＥＭ）により直接観察できる。または、粉末Ｘ線回折を用いることによって確認することができる。Ｘ線源として波長１．５４０５９ÅのＣｕＫα線を用い、２θ＝２０度～８０度の範囲で測定を行う。得られる回折スペクトルにおいては、結晶子サイズが小さくなるにつれて、比較的ブロードな回折ピークが観測される。粉末Ｘ線回折分析で得られるピークの半値幅から、Ｓｃｈｅｒｒｅｒの式を用いて求めることができる（Ｄ（Å）＝（Ｋ×λ）／（β×ｃｏｓθ）Ｄ：結晶子の大きさ、Ｋ：Ｓｃｈｅｒｒｅｒの定数、λ：使用Ｘ線管球の波長、β：結晶子の大きさによる回折線の拡がり、θ：回折角）。金属間化合物の結晶子サイズの制御については、原料粉末を溶解した後の凝固時の冷却速度の制御によって可能である。製造方法としては、水アトマイズ、単ロール急冷法、双ロール急冷法、ガスアトマイズ法、ディスクアトマイズ法、遠心アトマイズ等があるが、この限りではない。また、上記プロセスで冷却効果が不十分な場合、メカニカルミリング等を行うことも可能である。ミリング方法としては、ボールミル、ビーズミル、遊星ボールミル、アトライタ、振動ボールミル等があるが、この限りではない。 The crystallite size of the intermetallic compound can also be directly observed with a transmission electron microscope (TEM). Alternatively, it can be confirmed by using powder X-ray diffraction. A CuKα ray having a wavelength of 1.54059 mm is used as an X-ray source, and measurement is performed in the range of 2θ = 20 degrees to 80 degrees. In the obtained diffraction spectrum, a relatively broad diffraction peak is observed as the crystallite size decreases. From the full width at half maximum of the peak obtained by powder X-ray diffraction analysis, it can be determined using the Scherrer equation (D (Å) = (K × λ) / (β × cos θ) D: crystallite size, K : Scherrer constant, λ: wavelength of X-ray tube used, β: broadening of diffraction line depending on crystallite size, θ: diffraction angle). The crystallite size of the intermetallic compound can be controlled by controlling the cooling rate during solidification after dissolving the raw material powder. Examples of the production method include water atomization, single-roll quenching method, twin-roll quenching method, gas atomization method, disk atomization method, and centrifugal atomization, but are not limited thereto. Further, when the cooling effect is insufficient in the above process, mechanical milling or the like can be performed. Examples of the milling method include a ball mill, a bead mill, a planetary ball mill, an attritor, and a vibration ball mill, but are not limited thereto.
　ＣｒとＴｉを合計２１．１～４０％含み（ただしＴｉが０ａｔ．％の場合を含む）、Ｃｒ％／（Ｃｒ％＋Ｔｉ％）が０．１５～１．００の範囲とした理由は、本発明合金においてＣｒはＳｉ相と共晶組織を形成するＳｉ2 Ｃｒを生成する必須元素であり、ＴｉはＣｒに置換しＳｉ2 Ｃｒの格子定数を増加させる有効な元素だからである。また、Ｓｉの乏しい電子導電性をＳｉ化合物相が補い、かつＣｒやＴｉによる初期容量可逆率の向上が認められる。ＣｒとＴｉの合計量が２１．１％以上であれば、充放電時のＳｉの体積膨張収縮をＳｉ化合物相が緩和することが可能であり、電極内での活物質の電気電子的孤立化を防止し、サイクル特性が顕著に劣化することを防ぐことができる。さらに、ＣｒとＴｉの合計量が４０％以下であれば、Ｌｉを吸蔵・放出するＳｉ相の割合の低下を防ぎ、高い放電容量が得られる。したがって、ＣｒとＴｉの含有量を合計で２１．１～４０％とすることで、電極の電子伝導性を高め、充放電時のＳｉ相の体積膨張収縮による応力を抑制可能な量のＳｉ化合物相を確保することが可能となる。ＣｒとＴｉの合計において、好ましい範囲は２２～３５％、より好ましくは２３～３０％とした。また、Ｃｒ％／（Ｃｒ％＋Ｔｉ％）の好ましい範囲は、０．１５～０．９０、より好ましくは０．２０～０．８０とした。 The reason why Cr and Ti are included in a total range of 21.1 to 40% (including the case where Ti is 0 at.%) And Cr% / (Cr% + Ti%) is in the range of 0.15 to 1.00 is as follows. This is because, in the invention alloy, Cr is an essential element for forming Si 2 Cr that forms a eutectic structure with the Si phase, and Ti is an effective element that substitutes for Cr and increases the lattice constant of Si 2 Cr. Moreover, the Si compound phase supplements the electron conductivity with which Si is poor, and the improvement of the initial capacity reversal rate by Cr or Ti is recognized. If the total amount of Cr and Ti is 21.1% or more, the Si compound phase can relax the volume expansion and contraction of Si during charge and discharge, and the electrical and electronic isolation of the active material in the electrode It is possible to prevent the cycle characteristics from being significantly deteriorated. Furthermore, if the total amount of Cr and Ti is 40% or less, a reduction in the proportion of the Si phase that occludes and releases Li is prevented, and a high discharge capacity is obtained. Therefore, by making the total content of Cr and Ti 21.1 to 40%, the amount of the Si compound can be increased to increase the electron conductivity of the electrode and to suppress the stress due to the volume expansion and contraction of the Si phase during charge and discharge. It becomes possible to secure the phase. The total range of Cr and Ti is preferably 22 to 35%, more preferably 23 to 30%. The preferable range of Cr% / (Cr% + Ti%) is 0.15 to 0.90, more preferably 0.20 to 0.80.
　さらに、Ｓｉと金属間化合物を形成するＣｒとの合金であるＳｉｘＣｒｙ合金、Ｃｒ、Ｔｉとの合金であるＳｉｘ（Ｃｒ、Ｔｉ）ｙ合金において、Ｓｉｘ（Ｃｒ、Ｔｉ）ｙ相の組成がｘ＞ｙであることが必要である。高容量を得るために欠かせないＳｉ主要相が晶出するのがｘ＞ｙの時であり、好ましくはｘ＝２、ｙ＝１とする。 Further, in the SixCry alloy that is an alloy of Si and Cr that forms an intermetallic compound, and the Six (Cr, Ti) y alloy that is an alloy of Cr and Ti, the composition of the Six (Cr, Ti) y phase is x> It must be y. The Si main phase indispensable for obtaining a high capacity is crystallized when x> y, and preferably x = 2 and y = 1.
　また、本発明によるリチウムイオン二次電池用負極材料に関して、ＣｒおよびＴｉ以外にもＳｉと共晶合金を形成し微細Ｓｉ相が得られることから、Ｓｉよりも導電性がよく柔軟な金属間化合物を形成するＣｕ、Ｖ、Ｍｎ、Ｆｅ、Ｎｉ、Ｎｂ、ＺｎおよびＡｌといった添加元素の一種以上を更に含有させることができる。これらの添加により金属間化合物の結晶子サイズを制御することで、化合物相が微細Ｓｉ相の周囲を取り囲み、Ｓｉの微粉化、Ｓｉへのリチウムの吸蔵・放出時の体積膨張により生じる応力を緩和し、電極の崩壊およびＳｉの電気的孤立を防ぐ役割を果たす。 In addition, regarding the negative electrode material for lithium ion secondary batteries according to the present invention, a fine Si phase is obtained by forming a eutectic alloy with Si in addition to Cr and Ti, so that the intermetallic compound is more conductive and flexible than Si. One or more additive elements such as Cu, V, Mn, Fe, Ni, Nb, Zn, and Al can be further included. By controlling the crystallite size of the intermetallic compound by adding these, the compound phase surrounds the periphery of the fine Si phase, relieving the stress caused by volumetric expansion when Si is pulverized and lithium is absorbed into and released from Si. In addition, it plays the role of preventing the collapse of the electrode and the electrical isolation of Si.
　また、本発明によるリチウムイオン二次電池用負極材料に関して、ＣｒおよびＴｉ以外にもＳｉと共晶合金を形成し微細Ｓｉ相が得られることから、Ｓｉよりも導電性がよく柔軟な金属間化合物を形成するＭｇ、Ｂ、ＰおよびＧａといった添加元素の一種以上を、合計で０．０５ａｔ．％～５ａｔ．％含有し、結晶子サイズを制御することで、化合物相が微細Ｓｉ相の周囲を取り囲み、Ｓｉの微粉化、Ｓｉへのリチウムの吸蔵・放出時の体積膨張により生じる応力を緩和し、電極の崩壊、Ｓｉの電気的孤立を防ぐ役割を果たす。また、Ｂ添加によるＰ型半導体構造をとることで、Ｓｉの電気伝導性の向上の役割を果たす。Ｐ添加によるＮ型半導体構造をとることで、Ｓｉの電気伝導性の向上の役割を果たす。 In addition, regarding the negative electrode material for lithium ion secondary batteries according to the present invention, a fine Si phase is obtained by forming a eutectic alloy with Si in addition to Cr and Ti, so that the intermetallic compound is more conductive and flexible than Si. One or more of additive elements such as Mg, B, P, and Ga that form a total of 0.05 at. % To 5 at. By controlling the crystallite size, the compound phase surrounds the periphery of the fine Si phase, and mitigates the stress caused by the pulverization of Si and the volume expansion at the time of insertion and extraction of lithium into and from the Si. It plays a role in preventing collapse and electrical isolation of Si. Also, by taking a P-type semiconductor structure by adding B, it plays a role of improving the electrical conductivity of Si. By taking an N-type semiconductor structure by adding P, it plays a role of improving the electrical conductivity of Si.
　Ｓｉの体積膨張収縮により生じる応力を小さくする効果を付与するには、Ｃｕ、Ｖ、Ｍｎ、Ｆｅ、Ｎｉ、Ｎｂ、Ｐｄ、ＺｎおよびＡｌの合計含有量が０．０５ａｔ．％以上必要であり、５ａｔ．％以下であればリチウム不活性元素量が増えず、充放電容量の低下を防ぐことができる。このため、Ｃｕ、Ｖ、Ｍｎ、Ｆｅ、Ｎｉ、Ｎｂ、Ｐｄ、ＺｎおよびＡｌから少なくとも一種含まれる添加元素の合計含有量は０．０５ａｔ．％～５ａｔ．％が望ましい。より好ましくは０．１ａｔ．％～３ａｔ．％である。他にも同様の効果を狙った、Ｃｏ、Ｚｒ、Ｐｄ、Ｂｉ、Ｉｎ、Ｓｂ、ＳｎおよびＭｏについても、少なくとも一種含まれる添加元素の合計含有量を０．０５ａｔ．％～５ａｔ．％とすることが望ましい。 In order to give the effect of reducing the stress caused by the volume expansion and contraction of Si, the total content of Cu, V, Mn, Fe, Ni, Nb, Pd, Zn and Al is 0.05 at. % Or more, 5 at. % Or less, the amount of the lithium inert element does not increase, and a decrease in charge / discharge capacity can be prevented. Therefore, the total content of additive elements contained at least one of Cu, V, Mn, Fe, Ni, Nb, Pd, Zn, and Al is 0.05 at. % To 5 at. % Is desirable. More preferably, 0.1 at. % To 3 at. %. In addition, Co, Zr, Pd, Bi, In, Sb, Sn, and Mo aiming at the same effect are also set to 0.05 at. % To 5 at. % Is desirable.
　Ｓｉの体積膨張収縮により生じる応力を小さくする効果を付与するには、Ｍｇ、Ｂ、ＰおよびＧａの合計含有量が０．０５ａｔ．％以上必要であり、５ａｔ．％以下であればリチウム不活性元素量が増えず、充放電容量の低下を防ぐことができる。このため、Ｍｇ、Ｂ、ＰおよびＧａから少なくとも一種含まれる添加元素の合計含有量は０．０５ａｔ．％～５ａｔ．％が望ましい。より好ましくは０．１ａｔ．％～３ａｔ．％である。他にも同様の効果を狙ったＣｏ、Ｚｒ、Ｐｄ、Ｂｉ、Ｉｎ、Ｓｂ、ＳｎおよびＭｏについても、少なくとも一種以上含まれる添加元素の合計含有量を０．０５ａｔ．％～５ａｔ．％とすることが望ましい。 In order to give the effect of reducing the stress caused by the volume expansion and contraction of Si, the total content of Mg, B, P and Ga is 0.05 at. % Or more, 5 at. % Or less, the amount of the lithium inert element does not increase, and a decrease in charge / discharge capacity can be prevented. For this reason, the total content of additive elements contained at least one of Mg, B, P and Ga is 0.05 at. % To 5 at. % Is desirable. More preferably, 0.1 at. % To 3 at. %. In addition, Co, Zr, Pd, Bi, In, Sb, Sn, and Mo aiming at similar effects also have a total content of at least one additive element of 0.05 at. % To 5 at. % Is desirable.
　上記リチウムイオン二次電池負極材料を用いることにより、高容量かつ繰り返し充放電時のサイクル特性に優れ、またサイクル初期の充放電効率に優れた電池特性を示す。また、上記リチウムイオン二次電池負極材料を用いた電極において、結合性に優れるポリイミド系バインダーを含むことで、Ｃｕ等の集電体との密着性を高め、高容量を保持したまま、充放電サイクル特性を改善する効果が得られる。 By using the above-described lithium ion secondary battery negative electrode material, the battery characteristics of high capacity, excellent cycle characteristics during repeated charge / discharge, and excellent charge / discharge efficiency at the beginning of the cycle are exhibited. In addition, in the electrode using the lithium ion secondary battery negative electrode material, by including a polyimide-based binder having excellent binding properties, the adhesion with a current collector such as Cu is improved, and charging and discharging are performed while maintaining a high capacity. The effect of improving the cycle characteristics can be obtained.
　以下、本発明について、実施例により具体的に説明する。
　表１～２に示す組成のリチウムイオン二次電池用負極材料粉末を、以下に述べる単ロール急冷法、ガスアトマイズ法等により作製した。単ロール急冷法である液体急冷法については、所定組成の原料を底部に細孔を設けた石英管内に入れ、Ａｒ雰囲気中で高周波溶解して溶湯を形成し、この溶湯を回転する銅ロールの表面に出湯した後、銅ロールによる急冷効果によりＳｉ相の結晶子サイズの微細化を図った急冷リボンを作製した。その後、作製した急冷リボンをジルコニア製あるいはＳＵＳ３０４製、ＳＵＪ２製のポット容器内にジルコニアボールあるいはＳＵＳ３０４ボール、ＳＵＪ２ボールとともにＡｒ雰囲気中にて密閉し、粒子状に加工することを目的としたミリングを行った。ミリングに関しては、ボールミル、ビーズミル、遊星ボールミル、アトライタ、振動ボールミル等が挙げられる。 Hereinafter, the present invention will be specifically described with reference to examples.
Negative electrode material powders for lithium ion secondary batteries having the compositions shown in Tables 1 and 2 were prepared by a single roll quenching method, a gas atomizing method, or the like described below. For the liquid quenching method, which is a single roll quenching method, a raw material having a predetermined composition is placed in a quartz tube having pores at the bottom, melted at a high frequency in an Ar atmosphere to form a molten metal, and a copper roll that rotates this molten metal. After the hot water was discharged on the surface, a quenching ribbon was prepared in which the crystallite size of the Si phase was refined by the quenching effect of the copper roll. The milled ribbon is then sealed in an Ar atmosphere together with zirconia balls, SUS304 balls, or SUJ2 balls in a zirconia, SUS304, or SUJ2 pot container and milled for the purpose of processing into particles. It was. As for milling, a ball mill, a bead mill, a planetary ball mill, an attritor, a vibrating ball mill, and the like can be given.
　ガスアトマイズ法については、所定組成の原料を、底部に細孔を設けた石英坩堝内に入れ、Ａｒガス雰囲気中で高周波誘導溶解炉により加熱溶融した後、Ａｒガス雰囲気中で、ガス噴射させるとともに出湯させて、急冷凝固することでガスアトマイズ微粉末を得た。ディスクアトマイズ法については、所定組成の原料を、底部に細孔を設けた石英坩堝内に入れ、Ａｒガス雰囲気中で高周波誘導溶解炉により加熱溶融した後、Ａｒガス雰囲気中で、４００００～６００００ｒ．ｐ．ｍ．の回転ディスク上に出湯させて、急冷凝固することでディスクアトマイズ微粉末を得た。その後、作製したアトマイズ微粉末をジルコニア製あるいはＳＵＳ３０４製、ＳＵＪ２製のポット容器内にジルコニアボールあるいはＳＵＳ３０４ボール、ＳＵＪ２ボールとともにＡｒ雰囲気中にて密閉し、メカニカルミリングにより粉末化し、結晶子サイズの制御を行った。メカニカルミリングに関しては、ボールミル、ビーズミル、遊星ボールミル、アトライタ、振動ボールミル等が挙げられる。メカニカルミリングによる処理では、ミリング時間や回転数等を設定することで、急冷凝固を利用したアトマイズ粉末のＳｉ結晶子サイズや金属間化合物の結晶子サイズを制御することができる。 Regarding the gas atomization method, a raw material having a predetermined composition is placed in a quartz crucible having pores at the bottom, heated and melted in a high-frequency induction melting furnace in an Ar gas atmosphere, and then subjected to gas injection in an Ar gas atmosphere and a tapping hot water. Then, gas atomized fine powder was obtained by rapid solidification. In the disk atomization method, a raw material having a predetermined composition is placed in a quartz crucible having pores at the bottom, heated and melted in a high-frequency induction melting furnace in an Ar gas atmosphere, and then in an Ar gas atmosphere, 40000 to 60000 r. p. m. The hot water was discharged onto a rotating disk of No. 1 and rapidly solidified to obtain a disk atomized fine powder. Thereafter, the produced atomized fine powder is sealed in a zirconia or SUS304 / SUJ2 pot container in an Ar atmosphere together with zirconia balls, SUS304 balls, or SUJ2 balls, and powdered by mechanical milling to control the crystallite size. went. Examples of mechanical milling include a ball mill, a bead mill, a planetary ball mill, an attritor, and a vibrating ball mill. In the processing by mechanical milling, the crystallite size of the atomized powder and the intermetallic compound using rapid solidification can be controlled by setting the milling time and the number of rotations.
　以下、具体的な負極作製方法について述べる。
　上記負極の単極での電極性能を評価するために、対極にリチウム金属を用いた、いわゆる二極式コイン型セルを用いた。まず、負極活物質（Ｓｉ－Ｃｒ－Ｔｉなど）、導電材料（アセチレンブラック）、結着材料（ポリイミド、ポリフッ化ビニリデン等）を電子天秤で秤量し、分散液（Ｎ－メチルピロリドン）と共に混合スラリー状態とした後、集電体（Ｃｕ等）上に均一に塗布した。塗布後、真空乾燥機で減圧乾燥し溶媒を蒸発させた後、必要に応じてロールプレスした後、コインセルにあった形状に打ち抜いた。対極のリチウムも同様に金属リチウム箔をコインセルにあった形状に打ち抜いた。前記スラリー塗布電極の真空乾燥において、ポリイミド結着材料使用時は性能を十分に発揮するため２００℃以上の温度で乾燥した。ポリフッ化ビニリデン等使用時は約１６０℃の温度で乾燥した。 Hereinafter, a specific method for preparing a negative electrode will be described.
In order to evaluate the electrode performance of the negative electrode as a single electrode, a so-called bipolar coin-type cell using lithium metal as a counter electrode was used. First, a negative electrode active material (Si—Cr—Ti, etc.), a conductive material (acetylene black), a binder material (polyimide, polyvinylidene fluoride, etc.) are weighed with an electronic balance, and mixed with a dispersion (N-methylpyrrolidone). After making it into a state, it was uniformly applied on a current collector (Cu or the like). After coating, the solvent was evaporated by vacuum drying with a vacuum dryer, and then roll-pressed as necessary, and then punched into a shape suitable for the coin cell. Similarly, lithium for the counter electrode was punched into a shape suitable for the coin cell. In the vacuum drying of the slurry-coated electrode, when the polyimide binder material was used, it was dried at a temperature of 200 ° C. or higher in order to fully exhibit the performance. When using polyvinylidene fluoride or the like, it was dried at a temperature of about 160 ° C.
　リチウムイオン電池に使用する電解液はエチレンカーボネートとジメチルカーボネートの３：７混合溶媒を用い、支持電解質にはＬｉＰＦ6 （六フッ化リン酸リチウム）を用い、電解液に対して１モル溶解した。その電解液は露点管理された不活性雰囲気中で取り扱う必要があるため、セルの組立ては、全て不活性雰囲気のグローブボックス内で行った。セパレータはコインセルにあった形状に切り抜いた後セパレータ内に電解液を十分浸透させるために、減圧下で数時間電解液中に保持した。その後、前工程で打ち抜いた負極、セパレータ、対極リチウムの順に組合せ、電池内部を電解液で十分満たした形で構築した。 The electrolyte used for the lithium ion battery was a 3: 7 mixed solvent of ethylene carbonate and dimethyl carbonate, LiPF 6 (lithium hexafluorophosphate) was used as the supporting electrolyte, and 1 mol was dissolved in the electrolyte. Since the electrolyte solution must be handled in an inert atmosphere with dew point control, the cells were all assembled in a glove box with an inert atmosphere. The separator was cut out in a shape suitable for a coin cell and then held in the electrolyte for several hours under reduced pressure in order to sufficiently permeate the electrolyte into the separator. Thereafter, the negative electrode punched out in the previous step, the separator, and the counter electrode lithium were combined in this order, and the inside of the battery was sufficiently filled with the electrolytic solution.
　充電容量、放電容量の測定として、上記二極式セルを用い、温度２５℃、充電は０．５０ｍＡ／ｃｍ2 の電流密度で、金属リチウム極と同等の電位（０Ｖ）になるまで行い、同じ電流値（０．５０ｍＡ／ｃｍ2 ）で、放電を１．５Ｖまで行い、この充電－放電を１サイクルとした。また、サイクル寿命は、上記測定を繰返し行うことで評価した。 The measurement of charge capacity and discharge capacity was performed using the above-mentioned bipolar cell, at a temperature of 25 ° C., and charged at a current density of 0.50 mA / cm 2 until the same potential (0 V) as that of the metal lithium electrode. At a current value (0.50 mA / cm 2 ), discharging was performed up to 1.5 V, and this charging-discharging was defined as one cycle. The cycle life was evaluated by repeating the above measurement.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
 　表１、表２に示すように、Ｎｏ．１～４８は本発明例であり、表３～表５に示すようにＮｏ．４９～１１９は比較例を示す。
Figure JPOXMLDOC01-appb-T000005
 As shown in Tables 1 and 2, no. Nos. 1 to 48 are examples of the present invention. Reference numerals 49 to 119 denote comparative examples.
　本発明例のＮｏ．１～１２はＳｉ主要相とＳｉとＣｒとＴｉからなる相を含み、Ｓｉの結晶子サイズが３０ｎｍ以下であり、ＳｉとＣｒとＴｉからなる化合物相の結晶子サイズが４０ｎｍ以下の条件を満足している。 No. of the present invention example. 1 to 12 include the Si main phase and the phase composed of Si, Cr and Ti, the crystallite size of Si is 30 nm or less, and the crystallite size of the compound phase composed of Si, Cr and Ti satisfies the condition of 40 nm or less is doing.
　本発明例Ｎｏ．４では、Ｓｉ主要相とＳｉとＣｒとＴｉを含み、Ｓｉの結晶子サイズは３ｎｍであり、Ｓｉの結晶子サイズ３０ｎｍ以下の条件を満たしている。かつ、ＳｉとＣｒとＴｉからなる化合物相の結晶子サイズが３１ｎｍであり、ＳｉとＣｒとＴｉからなる化合物相の結晶子サイズ４０ｎｍ以下の条件を満足している。また、上記のように本発明条件を満たし、初期放電容量が７８９ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が９２％と充放電容量とサイクル寿命のいずれも良好な特性を示した。 Invention Example No. No. 4 contains Si main phase, Si, Cr, and Ti, the crystallite size of Si is 3 nm, and the condition that the crystallite size of Si is 30 nm or less is satisfied. In addition, the crystallite size of the compound phase composed of Si, Cr, and Ti is 31 nm, and the condition that the crystallite size of the compound phase composed of Si, Cr, and Ti is 40 nm or less is satisfied. Further, as described above, the present invention conditions were satisfied, the initial discharge capacity was 789 mAh / g, the discharge capacity retention rate after 50 cycles was 92%, and both the charge / discharge capacity and the cycle life showed good characteristics.
　本発明例のＮｏ．１３～１８はＳｉ主要相とＳｉとＣｒからなる相を含み、Ｓｉの結晶子サイズが３０ｎｍ以下であり、ＳｉとＣｒからなる化合物相の結晶子サイズが４０ｎｍ以下の条件を満足している。 No. of the present invention example. 13 to 18 include a Si main phase and a phase composed of Si and Cr, the crystallite size of Si is 30 nm or less, and the crystallite size of the compound phase composed of Si and Cr satisfies the condition of 40 nm or less.
　本発明例Ｎｏ．１４では、Ｓｉ主要相とＳｉとＣｒを含み、Ｓｉの結晶子サイズは５ｎｍであり、Ｓｉの結晶子サイズ３０ｎｍ以下の条件を満たしている。かつ、ＳｉとＣｒからなる化合物相の結晶子サイズが１４ｎｍであり、ＳｉとＣｒからなる化合物相の結晶子サイズ４０ｎｍ以下の条件を満足している。また、上記のように本発明条件を満たし、放電容量が９８９ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が８３％と充放電容量とサイクル寿命のいずれも良好な特性を示した。 Invention Example No. No. 14 contains a Si main phase, Si, and Cr, the Si crystallite size is 5 nm, and satisfies the condition that the Si crystallite size is 30 nm or less. And the crystallite size of the compound phase consisting of Si and Cr is 14 nm, and the crystallite size of the compound phase consisting of Si and Cr is 40 nm or less. Further, as described above, the present invention conditions were satisfied, the discharge capacity was 989 mAh / g, the discharge capacity retention rate after 50 cycles was 83%, and both the charge / discharge capacity and the cycle life showed good characteristics.
　本発明例のＮｏ．１９～２４はＳｉ主要相とＳｉとＣｒとＴｉからなる相を含み、Ｓｉの結晶子サイズが３０ｎｍ以下であり、ＳｉとＣｒとＴｉからなる化合物相の結晶子サイズが４０ｎｍ以下の条件を満足している。 No. of the present invention example. 19 to 24 include a Si main phase and a phase composed of Si, Cr, and Ti. The crystallite size of Si is 30 nm or less, and the crystallite size of the compound phase composed of Si, Cr, and Ti is 40 nm or less. is doing.
　本発明例Ｎｏ．２３では、Ｓｉ主要相とＳｉとＣｒとＴｉを含み、Ｓｉの結晶子サイズは９ｎｍであり、Ｓｉの結晶子サイズ３０ｎｍ以下の条件を満たしている。かつ、ＳｉとＣｒとＴｉからなる化合物相の結晶子サイズが１５ｎｍであり、ＳｉとＣｒとＴｉからなる化合物相の結晶子サイズ４０ｎｍ以下の条件を満足している。また、上記のように本発明条件を満たし、放電容量が６７４ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が８４％と充放電容量とサイクル寿命のいずれも良好な特性を示した。 Invention Example No. No. 23 includes Si main phase, Si, Cr, and Ti, the Si crystallite size is 9 nm, and satisfies the condition that the Si crystallite size is 30 nm or less. In addition, the crystallite size of the compound phase composed of Si, Cr and Ti is 15 nm, and the crystallite size of the compound phase composed of Si, Cr and Ti is 40 nm or less. Further, as described above, the conditions of the present invention were satisfied, the discharge capacity was 674 mAh / g, the discharge capacity retention rate after 50 cycles was 84%, and both the charge / discharge capacity and the cycle life showed good characteristics.
　本発明例のＮｏ．２５～５５はＳｉ主要相とＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる相を含み、Ｓｉ主要相のＳｉ結晶子サイズが３０ｎｍ以下であり、ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる化合物相の結晶子サイズが４０ｎｍ以下の条件を満足している。また、Ｃｕ、Ｖ、Ｍｎ、Ｆｅ、Ｎｉ、Ｎｂ、ＺｎおよびＡｌから少なくとも一種含まれる添加元素の合計含有量は、０．０５ａｔ．％～５ａｔ．％である。また、Ｍｇ、Ｂ、ＰおよびＧａから少なくとも一種類以上含まれる添加元素の合計含有量は０．０５ａｔ．％～５ａｔ．％である。同様の効果を狙った、Ｃｏ、Ｚｒ、Ｐｄ、Ｂｉ、Ｉｎ、ＳｂおよびＳｎ等の微量添加も含む。 No. of the present invention example. 25 to 55 include a Si main phase and a phase composed of Si and Cr, or Si, Cr and Ti. The Si main phase has a Si crystallite size of 30 nm or less, and is composed of Si and Cr, or Si, Cr and Ti. The crystallite size of the compound phase satisfies the condition of 40 nm or less. The total content of additive elements contained at least one of Cu, V, Mn, Fe, Ni, Nb, Zn and Al is 0.05 at. % To 5 at. %. Further, the total content of additive elements contained at least one or more of Mg, B, P and Ga is 0.05 at. % To 5 at. %. Including a small amount of addition of Co, Zr, Pd, Bi, In, Sb, Sn, etc. aiming at the same effect.
　例えば、Ｎｏ．３９では、Ｓｉ主要相とＳｉとＣｒとＴｉを含み、Ｓｉの結晶子サイズは１５ｎｍであり、Ｓｉの結晶子サイズ３０ｎｍ以下の条件を満たしている。かつ、ＳｉとＣｒとＴｉからなる化合物相の結晶子サイズが３２ｎｍであり、ＳｉとＣｒとＴｉからなる化合物相の結晶子サイズ４０ｎｍ以下の条件を満足している。加えて、０．０１ａｔ．％Ｃｕ、０．０３ａｔ．％Ｖ、０．０１ａｔ．％Ｍｎ、０．０１ａｔ．％Ｆｅ、０．０１ａｔ．％Ｎｉ、０．０２ａｔ．％Ｚｎ、０．０２ａｔ．％Ａｌを含んでいる。また、０．０１ａｔ．％Ｃｏ、０．１４ａｔ．％Ｂｉ、０．１５ａｔ．％Ｉｎ、０．１５ａｔ．％Ｓｂ、０．１５ａｔ．％Ｓｎを含んでいる。上記のように本発明条件を満たし、放電容量が１０７９ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が８５％と充放電容量とサイクル寿命のいずれも良好な特性を示した。 For example, No. No. 39 contains Si main phase, Si, Cr, and Ti, the crystallite size of Si is 15 nm, and satisfies the condition that the crystallite size of Si is 30 nm or less. In addition, the crystallite size of the compound phase composed of Si, Cr and Ti is 32 nm, and the crystallite size of the compound phase composed of Si, Cr and Ti is 40 nm or less. In addition, 0.01 at. % Cu, 0.03 at. % V, 0.01 at. % Mn, 0.01 at. % Fe, 0.01 at. % Ni, 0.02 at. % Zn, 0.02 at. % Al is contained. In addition, 0.01 at. % Co, 0.14 at. % Bi, 0.15 at. % In, 0.15 at. % Sb, 0.15 at. % Sn is included. As described above, the conditions of the present invention were satisfied, the discharge capacity was 1079 mAh / g, the discharge capacity retention rate after 50 cycles was 85%, and both the charge / discharge capacity and the cycle life showed good characteristics.
　例えば、比較例Ｎｏ．４９はＣｒを含まないため、また、ＣｒとＴｉの合計含有量が２１．１～４０ａｔ．％の範囲を含まず、ＣｒとＴｉの比率であるＣｒ％／（Ｃｒ％＋Ｔｉ％）が０．１５～１．００の範囲でないため、本発明条件を満たさない。また、比較例Ｎｏ．８１では、ＣｒとＴｉの合計含有量が２１．１～４０ａｔ．％の範囲を含まず、ＣｒとＴｉの比率であるＣｒ％／（Ｃｒ％＋Ｔｉ％）が０．１５～１．００の範囲でないため、かつ、Ｓｉの結晶子サイズ３０ｎｍ以下の条件を満たさないため、本発明条件を満たさない。比較例Ｎｏ．１０６では、ＣｒとＴｉの合計含有量が２１．１～４０ａｔ．％の範囲を含まず、ＣｒとＴｉの比率であるＣｒ％／（Ｃｒ％＋Ｔｉ％）が０．１５～１．００の範囲でないため、かつ、Ｓｉの結晶子サイズ３０ｎｍ以下の条件を満たさず、化合物相の結晶子サイズが４０ｎｍ以下の条件も満たさないため、本発明条件を満たさない。 For example, Comparative Example No. 49 does not contain Cr, and the total content of Cr and Ti is 21.1 to 40 at. %, And the Cr / Ti ratio Cr% / (Cr% + Ti%) is not in the range of 0.15 to 1.00, so the conditions of the present invention are not satisfied. Comparative Example No. 81, the total content of Cr and Ti is 21.1 to 40 at. %, The ratio of Cr to Ti, Cr% / (Cr% + Ti%) is not in the range of 0.15 to 1.00, and does not satisfy the condition of the Si crystallite size of 30 nm or less. Therefore, the conditions of the present invention are not satisfied. Comparative Example No. 106, the total content of Cr and Ti is 21.1 to 40 at. %, The ratio of Cr and Ti, Cr% / (Cr% + Ti%) is not in the range of 0.15 to 1.00, and the crystallite size of Si is 30 nm or less. The condition of the present invention is not satisfied because the crystallite size of the compound phase does not satisfy the condition of 40 nm or less.
　以上のように、組織の微細化、優れたイオン伝導性と電子伝導性、応力緩和効果を高める成分の制御と、Ｓｉ相結晶子サイズの制御、あるいはさらに金属間化合物相の結晶子サイズも制御することによって、よりスムーズな充放電反応を行うことができ、充放電サイクル特性の向上を可能とする。さらに、ポリイミド系バインダーを含むことで、Ｃｕ等の集電体との密着性を高め、かつＳｉの体積膨張収縮による応力にも耐えうる強度を有するため、高い充放電容量と優れたサイクル寿命を兼備する極めて優れた効果を有する。 As described above, refinement of the structure, control of components that enhance the excellent ion conductivity and electron conductivity, stress relaxation effect, control of the Si phase crystallite size, and further control of the crystallite size of the intermetallic compound phase By doing so, a smoother charge / discharge reaction can be performed, and charge / discharge cycle characteristics can be improved. Furthermore, by including a polyimide-based binder, it has high strength to withstand current stress due to volume expansion and contraction of Si, and has high charge / discharge capacity and excellent cycle life. It has an extremely excellent effect.

Claims (4)

  1. 　充放電時にリチウムイオンの移動が伴う蓄電デバイス用のＳｉ系合金からなる負極材料であって、
    　前記Ｓｉ系合金からなる負極材料が、
    　ＳｉからなるＳｉ主要相と
    　ＳｉとＳｉ以外の一種以上の元素からなる化合物相と
    を有し、
    　前記化合物相が、ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる相を含んでなる相を有し、
    　前記Ｓｉ主要相のＳｉ結晶子サイズが３０ｎｍ以下であり、
    　ＳｉとＣｒ、あるいはＳｉとＣｒとＴｉからなる前記化合物相の結晶子サイズが４０ｎｍ以下であり、
    　ＣｒとＴｉの合計含有量が２１．１～４０ａｔ．％であり、かつ、
    　ＣｒとＴｉの比率であるＣｒ％／（Ｃｒ％＋Ｔｉ％）が０．１５～１．００の範囲である、Ｓｉ系合金からなる負極材料。     A negative electrode material made of a Si-based alloy for an electricity storage device accompanied by movement of lithium ions during charge and discharge,
    The negative electrode material made of the Si-based alloy is
    Having a Si main phase composed of Si and a compound phase composed of one or more elements other than Si and Si;
    The compound phase has a phase comprising Si and Cr, or a phase comprising Si, Cr and Ti;
    Si crystallite size of the Si main phase is 30 nm or less,
    The crystallite size of the compound phase comprising Si and Cr or Si, Cr and Ti is 40 nm or less,
    The total content of Cr and Ti is 21.1 to 40 at. %, And
    A negative electrode material made of a Si-based alloy having a Cr / Ti ratio of Cr% / (Cr% + Ti%) in the range of 0.15 to 1.00.
  2. 　前記化合物相が、Ｃｕ、Ｖ、Ｍｎ、Ｆｅ、Ｎｉ、Ｎｂ、ＺｎおよびＡｌからなる群から選択される少なくとも一種の元素を、合計で０．０５ａｔ．％～５ａｔ．％含む、請求項１に記載のＳｉ系合金からなる負極材料。 The compound phase contains at least 0.05 at.m in total of at least one element selected from the group consisting of Cu, V, Mn, Fe, Ni, Nb, Zn and Al. % To 5 at. The negative electrode material which consists of Si type alloy of Claim 1 containing%.
  3. 　前記化合物相に、Ｍｇ、Ｂ、ＰおよびＧａからなる群から選択される少なくとも一種の元素を、合計で０．０５ａｔ．％～５ａｔ．％含む、請求項１または２に記載のＳｉ系合金からなる負極材料。 In the compound phase, at least one element selected from the group consisting of Mg, B, P and Ga is added in a total of 0.05 at. % To 5 at. The negative electrode material which consists of Si type alloy of Claim 1 or 2 containing%.
  4. 　請求項１～３のいずれか一項に記載のＳｉ系合金からなる負極材料を用いた電極において、ポリイミド系バインダーを含む、蓄電デバイス用のＳｉ系合金からなる負極。 A negative electrode made of a Si-based alloy for an electricity storage device, comprising a polyimide-based binder, in an electrode using the negative electrode material made of the Si-based alloy according to any one of claims 1 to 3.
PCT/JP2015/075119 2014-09-16 2015-09-03 Si-BASED ALLOY NEGATIVE ELECTRODE MATERIAL FOR ELECTRICITY STORAGE DEVICES AND ELECTRODE USING SAME WO2016043061A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1020177004242A KR20170057235A (en) 2014-09-16 2015-09-03 Si-BASED ALLOY NEGATIVE ELECTRODE MATERIAL FOR ELECTRICITY STORAGE DEVICES AND ELECTRODE USING SAME
CN201580046199.4A CN106605322A (en) 2014-09-16 2015-09-03 Si-based alloy negative electrode material for electricity storage devices and electrode using same

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2014-187238 2014-09-16
JP2014187238A JP6735060B2 (en) 2014-09-16 2014-09-16 Si-based alloy negative electrode material for power storage device and electrode using the same

Publications (1)

Publication Number Publication Date
WO2016043061A1 true WO2016043061A1 (en) 2016-03-24

Family

ID=55533101

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2015/075119 WO2016043061A1 (en) 2014-09-16 2015-09-03 Si-BASED ALLOY NEGATIVE ELECTRODE MATERIAL FOR ELECTRICITY STORAGE DEVICES AND ELECTRODE USING SAME

Country Status (5)

Country Link
JP (1) JP6735060B2 (en)
KR (1) KR20170057235A (en)
CN (1) CN106605322A (en)
TW (1) TW201616707A (en)
WO (1) WO2016043061A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017221693A1 (en) * 2016-06-21 2017-12-28 山陽特殊製鋼株式会社 Negative electrode material for electricity storage devices

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6859930B2 (en) * 2017-09-14 2021-04-14 株式会社豊田自動織機 Al-containing silicon material
WO2019053984A1 (en) * 2017-09-14 2019-03-21 株式会社豊田自動織機 Negative electrode active substance comprising al-containing silicon material
WO2019053983A1 (en) * 2017-09-14 2019-03-21 株式会社豊田自動織機 Negative electrode active material containing al-containing silicon material
JP7119895B2 (en) * 2018-10-24 2022-08-17 トヨタ自動車株式会社 Negative electrode active material
KR102654226B1 (en) 2023-05-08 2024-04-03 김경민 Manufacture system for fire protection pipe

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001297757A (en) * 2000-04-14 2001-10-26 Sumitomo Metal Ind Ltd Negative electrode material for nonaqueous electrolyte secondary cell and its manufacturing method
JP2005071771A (en) * 2003-08-22 2005-03-17 Samsung Sdi Co Ltd Negative electrode active material for lithium secondary battery,its manufacturing method, and lithium secondary battery
JP2012150910A (en) * 2011-01-17 2012-08-09 Sanyo Special Steel Co Ltd Si ALLOY POWDER FOR LITHIUM ION SECONDARY BATTERY NEGATIVE ELECTRODE AND MANUFACTURING METHOD FOR THE SAME
JP2012234788A (en) * 2011-04-20 2012-11-29 Sanyo Special Steel Co Ltd Silicon-based alloy cathode material
JP2013125743A (en) * 2011-12-13 2013-06-24 Samsung Sdi Co Ltd Negative electrode active material and secondary battery including the same
JP2013191529A (en) * 2012-02-16 2013-09-26 Hitachi Chemical Co Ltd Composite material, method for manufacturing composite material, electrode material for lithium ion secondary battery, negative electrode for lithium ion secondary battery, and lithium ion secondary battery
JP2014038832A (en) * 2012-07-20 2014-02-27 Sanyo Special Steel Co Ltd Material for negative electrode of electric power storage device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6322362B2 (en) * 2012-02-01 2018-05-09 山陽特殊製鋼株式会社 Si alloy negative electrode material
JP6371504B2 (en) * 2013-02-19 2018-08-08 山陽特殊製鋼株式会社 Si-based alloy negative electrode material for power storage device and electrode using the same

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001297757A (en) * 2000-04-14 2001-10-26 Sumitomo Metal Ind Ltd Negative electrode material for nonaqueous electrolyte secondary cell and its manufacturing method
JP2005071771A (en) * 2003-08-22 2005-03-17 Samsung Sdi Co Ltd Negative electrode active material for lithium secondary battery,its manufacturing method, and lithium secondary battery
JP2012150910A (en) * 2011-01-17 2012-08-09 Sanyo Special Steel Co Ltd Si ALLOY POWDER FOR LITHIUM ION SECONDARY BATTERY NEGATIVE ELECTRODE AND MANUFACTURING METHOD FOR THE SAME
JP2012234788A (en) * 2011-04-20 2012-11-29 Sanyo Special Steel Co Ltd Silicon-based alloy cathode material
JP2013125743A (en) * 2011-12-13 2013-06-24 Samsung Sdi Co Ltd Negative electrode active material and secondary battery including the same
JP2013191529A (en) * 2012-02-16 2013-09-26 Hitachi Chemical Co Ltd Composite material, method for manufacturing composite material, electrode material for lithium ion secondary battery, negative electrode for lithium ion secondary battery, and lithium ion secondary battery
JP2014038832A (en) * 2012-07-20 2014-02-27 Sanyo Special Steel Co Ltd Material for negative electrode of electric power storage device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017221693A1 (en) * 2016-06-21 2017-12-28 山陽特殊製鋼株式会社 Negative electrode material for electricity storage devices
JP2017228403A (en) * 2016-06-21 2017-12-28 山陽特殊製鋼株式会社 Negative electrode material for power storage device
CN108701821A (en) * 2016-06-21 2018-10-23 山阳特殊制钢株式会社 Electrical storage device negative material

Also Published As

Publication number Publication date
JP6735060B2 (en) 2020-08-05
KR20170057235A (en) 2017-05-24
TW201616707A (en) 2016-05-01
JP2016062660A (en) 2016-04-25
CN106605322A (en) 2017-04-26

Similar Documents

Publication Publication Date Title
JP6322362B2 (en) Si alloy negative electrode material
JP6371504B2 (en) Si-based alloy negative electrode material for power storage device and electrode using the same
JP6374678B2 (en) Negative electrode materials for electricity storage devices
WO2012144424A1 (en) Si-BASED ALLOY NEGATIVE ELECTRODE MATERIAL
TWI569497B (en) Negative electrode active material for lithium ion battery, and negative electrode for lithium ion battery using the same
WO2016043061A1 (en) Si-BASED ALLOY NEGATIVE ELECTRODE MATERIAL FOR ELECTRICITY STORAGE DEVICES AND ELECTRODE USING SAME
JP4739462B1 (en) Si-based alloy negative electrode material with excellent conductivity
JP2007149604A (en) Negative electrode for lithium secondary battery and lithium secondary battery
JP6076772B2 (en) Si-based alloy negative electrode material for power storage device and electrode using the same
WO2012008540A1 (en) Silicon-alloy negative-electrode material exhibiting high electrical conductivity and manufacturing method therefor
JP2017224499A (en) Negative electrode active material for lithium ion battery and lithium ion battery
JP2004235057A (en) Negative electrode for lithium secondary battery, and the battery
JP2009193686A (en) Positive electrode active material for nonaqueous electrolyte secondary battery and method of manufacturing the same
JP6371635B2 (en) Si-based alloy negative electrode material for power storage device and electrode using the same
JP4763970B2 (en) Negative electrode material for non-aqueous electrolyte secondary battery, negative electrode for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery
JPWO2013168786A1 (en) Negative electrode for lithium ion secondary battery
JP6245954B2 (en) Negative electrode active material for lithium ion secondary battery
JP4703110B2 (en) Negative electrode material for non-aqueous electrolyte secondary battery, negative electrode for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery
JP6630632B2 (en) Anode materials for power storage devices
WO2018193864A1 (en) Negative electrode material for power storage device
JP6045879B2 (en) Sn alloy powder used as a raw material of the negative electrode active material of a lithium ion secondary battery, and its manufacturing method.
JP2006155903A (en) Negative electrode material for nonaqueous electrolyte battery, negative electrode, and nonaqueous electrolyte battery using it
JP2008270130A (en) Negative electrode material for nonaqueous electrolyte battery, negative electrode using the same, and nonaqueous electrolyte battery

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15841850

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 20177004242

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15841850

Country of ref document: EP

Kind code of ref document: A1