WO2013187176A1 - Method for producing lithium ion secondary battery, and lithium ion secondary battery - Google Patents

Method for producing lithium ion secondary battery, and lithium ion secondary battery Download PDF

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Publication number
WO2013187176A1
WO2013187176A1 PCT/JP2013/063558 JP2013063558W WO2013187176A1 WO 2013187176 A1 WO2013187176 A1 WO 2013187176A1 JP 2013063558 W JP2013063558 W JP 2013063558W WO 2013187176 A1 WO2013187176 A1 WO 2013187176A1
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lithium
negative electrode
secondary battery
active material
metal
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PCT/JP2013/063558
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French (fr)
Japanese (ja)
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慎 芹澤
恵美子 藤井
入山　次郎
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日本電気株式会社
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Priority to JP2014521214A priority Critical patent/JP6112111B2/en
Publication of WO2013187176A1 publication Critical patent/WO2013187176A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a method for manufacturing a lithium ion secondary battery, and more particularly to a method for manufacturing a lithium ion secondary battery including a step of performing a lithium pre-doping process in the manufacturing process.
  • Patent Document 1 discloses that silicon oxide or a silicate compound is used as a negative electrode active material of a secondary battery as a negative electrode material having a large capacity.
  • a secondary battery using the oxide of silicon described in Patent Document 1 as a negative electrode active material is charged and discharged at 45 ° C. or higher, there is a problem that the capacity reduction accompanying the cycle is large.
  • Patent Document 2 and Patent Document 3 metal lithium foil is attached to a non-carbon negative electrode and heated. It is disclosed that lithium is diffused into a non-carbon negative electrode.
  • the non-carbon-based negative electrode described in Patent Document 2 is a method in which a lithium metal foil is pasted and diffused into the active material by a heating method so that the active material particles sufficiently occlude lithium before charging. This is a means of solving the problem of “lithium depletion” during charging and discharging.
  • lithium and a negative electrode are obtained by contacting a metal film mainly composed of lithium under heating and pressure on the surface of a layer containing a non-carbon negative electrode active material.
  • This is a means for solving the large irreversible capacity of the negative electrode active material such as silicon oxide by reacting with the active material and occluding lithium in the active material.
  • Patent Document 4 discloses a secondary battery including an active material layer including carbon material particles that can occlude and release lithium ions, metal particles that can be alloyed with lithium ions, and oxide particles that can occlude and release lithium ions.
  • a negative electrode is disclosed.
  • the negative electrode for a secondary battery described in Patent Document 4 has an effect of relaxing the volume change of the entire negative electrode when lithium is occluded and released due to the difference in charge / discharge potential of the three components.
  • a technique for forming a lithium metal film on the negative electrode surface is disclosed.
  • a lithium metal layer is provided on the active material layer to provide a means for solving the large irreversible capacity of the negative electrode active material.
  • a method for forming a lithium metal layer As a method for forming a lithium metal layer, a method for forming a film by bonding lithium metal to the negative electrode surface and melting it is shown in addition to a melt cooling method, a vacuum deposition method, a sputtering method, and the like.
  • Patent Documents 5 and 6 disclose a technique of doping lithium into silicon-silicon oxide composite particles coated with carbon.
  • Patent Documents 7 and 8 describe a method for producing lithium nitride.
  • Patent Document 9 describes a negative electrode in which a lithium nitride protective film is formed on a lithium metal surface.
  • Patent Documents 2 to 4 using a lithium metal foil or a metal film mainly composed of lithium as a lithium source, the negative electrode active material before battery completion is doped with lithium, that is, lithium pre-doped. It is disclosed. However, when lithium or a metal foil, piece, or molded product mainly composed of lithium is used as a pre-doped lithium source, there is a problem that the lithium doping amount is not stable within the electrode surface, for each electrode, and for each lot.
  • the energy density and cycle characteristics may not be sufficiently improved.
  • the present invention has been made to solve this problem, and is a lithium ion secondary battery in which irreversible capacity is reduced, cycle characteristics are improved with high energy density, by stably performing lithium pre-doping.
  • An object of the present invention is to provide a method of producing
  • the present invention is a method for producing a lithium ion secondary battery comprising a laminated electrode body in which a negative electrode and a positive electrode containing an active material capable of inserting and extracting lithium are arranged opposite to each other,
  • the present invention relates to a method for manufacturing a lithium ion secondary battery, comprising a step of bringing a lithium source having a surface layer containing 30% by mass or more of lithium nitride into contact with a negative electrode active material.
  • a secondary battery having a high energy density and good cycle characteristics can be provided.
  • An example of a laminated electrode elements included in the secondary battery according to the present embodiment is a cross-sectional view schematically showing.
  • An example of a lithium source used in the lithium pre-doping of the present embodiment is a cross-sectional view schematically showing. It is sectional drawing which shows typically an example of the lithium source which has a base material used for the lithium pre dope concerning this embodiment. It is sectional drawing which shows typically an example of the lithium source used for the conventional lithium pre dope.
  • the lithium pre-doping means that the negative electrode active material occludes lithium (doping with lithium) regardless of the charge after the battery is manufactured. Typically, in the process before the battery is completed. Means that the negative electrode active material occludes lithium (dope lithium).
  • an electrode body in which at least a pair of a positive electrode and a negative electrode are arranged to face each other, and an electrolytic solution are included in the exterior body.
  • the shape of the secondary battery may be any of a cylindrical type, a flat wound square type, a laminated square type, a coin type, a flat wound laminated type, and a laminated laminate type, and a laminated laminate type is preferable.
  • a laminated laminate type secondary battery will be described.
  • FIG. 1 shows a schematic cross-sectional view of an example of a laminated electrode body 1 included in a laminated laminate type secondary battery.
  • a plurality of positive electrodes 2 and a plurality of negative electrodes 3 are alternately stacked with the separator 4 interposed therebetween.
  • an active material uncoated portion where the positive electrode current collector 5 and the negative electrode current collector 6 are not covered with the active material is provided.
  • the positive electrode 2 and the negative electrode 3 are stacked with the active material uncoated portions facing in opposite directions.
  • the positive electrode current collector 5 is electrically connected to each other at an active material uncoated portion, and a positive electrode lead terminal 7 is further connected to the connection portion.
  • the negative electrode current collector 6 is electrically connected to each other at an active material uncoated portion, and a negative electrode lead terminal 8 is further connected to the connection portion.
  • a laminated laminate type secondary battery is manufactured by wrapping a laminated electrode body 1 with an exterior body such as an aluminum laminated film, injecting an electrolyte into the inside, and then sealing under reduced pressure.
  • the negative electrode 3 provided in the laminated electrode body 1 according to the present embodiment includes a negative electrode active material, a negative electrode binder, and a negative electrode current collector, and lithium before the production of the secondary battery or before electrode lamination.
  • a negative electrode for a secondary battery doped with it does not specifically limit as a negative electrode active material contained in the negative electrode 3,
  • As an active material of this embodiment only 1 type of these may be used, and 2 or more types may be mixed and used.
  • metals that can be alloyed with lithium include Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, and alloys of two or more of these. It is done.
  • silicon (Si) is preferably included as a metal that can be alloyed with lithium.
  • the metal content in the negative electrode active material is preferably 5% by mass to 95% by mass, more preferably 10% by mass to 90% by mass, and more preferably 20% by mass to 50% by mass. More preferably.
  • metal oxides that can occlude and release lithium ions include aluminum oxide, silicon oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, and composites thereof.
  • silicon oxide is preferably included as a metal oxide capable of inserting and extracting lithium ions.
  • one or more elements selected from nitrogen, boron, phosphorus and sulfur can be added to the metal oxide. By carrying out like this, the electrical conductivity of a metal oxide can be improved.
  • the content of the metal oxide in the negative electrode active material may be 0% by mass or 100% by mass, but is preferably 5% by mass or more and 100% by mass or less, and 40% by mass or more and 95% by mass or less. Is more preferable, and it is further more preferable to set it as 50 to 90 mass%.
  • these metal oxides is preferably in whole or in part has an amorphous structure. Since the metal oxide has an amorphous structure, it suppresses volume changes of other negative electrode active materials such as metals that can be alloyed with lithium and carbon materials that can occlude and release lithium ions, and suppresses decomposition of the electrolyte. Can be. Although this mechanism is not clear, it is presumed that the formation of a film on the interface between the carbon material and the electrolytic solution has some influence due to the amorphous structure of the metal oxide.
  • the amorphous structure is considered to have relatively few elements due to non-uniformity such as crystal grain boundaries and defects.
  • the metal oxide has an amorphous structure. Specifically, when the metal oxide does not have an amorphous structure, a peak specific to the metal oxide is observed. However, the metal oxide may have a case where all or part of the metal oxide has an amorphous structure. Inherent peaks are broad and observed.
  • the negative electrode active material contains a metal that can be alloyed with lithium and a metal oxide that can occlude and release lithium ions
  • all or a part of the alloyable metal is dispersed in the metal oxide.
  • the volume change as the whole negative electrode can be suppressed, and decomposition
  • all or part of the metal is dispersed in the metal oxide because transmission electron microscope observation (general TEM observation) and energy dispersive X-ray spectroscopy measurement (general EDX measurement). It can confirm by using together. Specifically, the cross section of the sample containing metal particles is observed, the oxygen concentration of the metal particles dispersed in the metal oxide is measured, and the metal constituting the metal particles is not an oxide. Can be confirmed.
  • the metal oxide is preferably an oxide of a metal constituting the metal.
  • the negative electrode active material containing a metal and a metal oxide is not particularly limited to the proportion of metals and metal oxides.
  • the metal is preferably 5% by mass or more and 90% by mass or less, and more preferably 30% by mass or more and 60% by mass or less, based on the total of the metal and the metal oxide.
  • the metal oxide is preferably 10% by mass or more and 95% by mass or less, and more preferably 40% by mass or more and 70% by mass or less, with respect to the total of the metal and the metal oxide.
  • Examples of carbon materials that can occlude and release lithium ions include graphite, amorphous carbon, diamond-like carbon, carbon nanotubes, and composites thereof.
  • graphite has high crystallinity, high electrical conductivity, and excellent adhesion to a current collector made of a metal such as copper and voltage flatness.
  • Amorphous carbon has low crystallinity and a relatively small volume change, so that the volume change of the entire negative electrode can be mitigated, and deterioration due to nonuniformity such as crystal agglomerates and defects occurs. Hateful.
  • the content of the carbon material in the negative electrode active material may be 0% by mass, but is preferably 1% by mass to 50% by mass, and more preferably 2% by mass to 30% by mass.
  • the negative electrode active material contains a metal that can be alloyed with lithium, a metal oxide that can occlude and release lithium ions, and a carbon material that can occlude and release lithium ions
  • the metal is preferably 5% by mass or more and 90% by mass or less, and more preferably 20% by mass or more and 50% by mass or less with respect to the total of the metal, the metal oxide, and the carbon material.
  • the metal oxide is preferably 5% by mass or more and 90% by mass or less, and more preferably 40% by mass or more and 70% by mass or less with respect to the total of the metal, the metal oxide, and the carbon material.
  • the carbon material is preferably 1% by mass or more and 50% by mass or less, and more preferably 2% by mass or more and 30% by mass or less with respect to the total of the metal, the metal oxide, and the carbon material.
  • the metal, metal oxide, and carbon material are not particularly limited, but particulate materials can be used.
  • the average particle size of the metal can be smaller than the average particle size of the metal oxide and the average particle size of the carbon material. In this way, metals with a large volume change during charge / discharge have a relatively small particle size, and metal oxides and carbon materials with a small volume change have a relatively large particle size. Micronization is more effectively suppressed.
  • lithium is occluded and released in the order of large-diameter particles, small-diameter particles, and large-diameter particles during the charge / discharge process. This also suppresses the occurrence of residual stress and residual strain. Is done.
  • the average particle diameter of the metal can be, for example, 10 ⁇ m or less, and is preferably 5 ⁇ m or less.
  • the carbon material may be localized near the surface of the particle in a state of covering the metal and the metal oxide. By localizing in the vicinity of the surface in this way, the aggregation of the metal and the metal oxide can be suppressed, the volume change of the negative electrode as a whole can be reduced, and further, the electron conductivity can be made uniform.
  • the negative electrode active material includes a metal, a metal oxide, and a carbon material, all or part of the metal oxide has an amorphous structure, all or part of the metal is dispersed in the metal oxide, and the carbon material is
  • a localized negative electrode active material can be produced by a method as disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-47404. That is, by performing a CVD process in an atmosphere containing an organic gas such as methane gas, a metal oxide in which metal in the metal oxide is nanoclustered and a surface is coated with a carbon material can be obtained. .
  • the said negative electrode active material is producible also by mixing a metal, a metal oxide, and a carbon material in steps by mechanical milling.
  • the negative electrode active material is preferably a negative electrode active material mainly composed of silicon.
  • Lithium silicate can be formed by performing lithium pre-doping on silicon and silicon oxide as described later. At that time, by controlling the valence of silicon, a negative electrode having a high capacity and a long life can be produced. Specifically, by forming silicon having an oxidation number of 0, a silicon compound having a silicon atom having an oxidation number of +4, and a silicon lower oxide having a silicon atom having an oxidation number of greater than 0 and less than +4, A negative electrode having a capacity and a long life can be produced.
  • the negative electrode active material may be doped with lithium in the form of a powder, and for example, it can be produced by the techniques described in Patent Document 5 and Patent Document 6.
  • a powdered active material and a lithium source for example, lithium metal, an organic lithium compound, lithium hydride, lithium aluminum hydride, etc. are mentioned, and lithium hydride and lithium aluminum hydride are preferable). They were mixed in a predetermined molar ratio, 100 °C ⁇ 800 °C, preferably heated at 200 °C ⁇ 800 °C.
  • lithium pre-doping treatment of the present embodiment described later (a step of bringing a lithium source having a predetermined surface layer into contact with the negative electrode active material) ) Can be implemented. Therefore, lithium pre-doping may be performed at least twice.
  • Negative electrode binders include polyvinylidene fluoride, modified polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer rubber, polytetrafluoroethylene.
  • Polypropylene polyethylene, polyacrylic acid, metal salt of polyacrylic acid, polyimide, polyamideimide and the like. In the present embodiment, it is preferable to include polyimide or polyamideimide.
  • the content of the binder for the negative electrode to be used is preferably 5 to 20% by mass with respect to the total mass of the negative electrode active material from the viewpoints of “sufficient binding force” and “high energy” which are in a trade-off relationship. 8 to 15% by mass is preferable.
  • Examples of the negative electrode current collector include aluminum, nickel, copper, silver, alloys thereof, and stainless steel.
  • Examples of the shape of the current collector include a foil, a flat plate, and a mesh.
  • a negative electrode active material, a conductivity imparting agent, and a binder are dispersed and kneaded in a solvent such as N-methyl-2-pyrrolidone (NMP) to prepare a negative electrode slurry.
  • NMP N-methyl-2-pyrrolidone
  • the conductive agent, carbon black, graphite, carbonaceous fine particles such as acetylene black When the carbon material is previously localized on the surface of the negative electrode active material, the conductivity imparting agent may not be included.
  • a negative electrode before lithium pre-doping can be prepared by applying the negative electrode slurry onto a negative electrode current collector such as a copper foil and drying the solvent. Examples of the coating method include a doctor blade method and a die coater method.
  • a thin film of aluminum, nickel, or an alloy thereof may be formed by a method such as vapor deposition or sputtering to form a negative electrode current collector.
  • a method such as vapor deposition or sputtering to form a negative electrode current collector.
  • desired heat processing can be performed as needed.
  • the polyamide precursor or a polyimide precursor preferably it contains the polyamic acid.
  • the negative electrode before lithium pre-doping may be manufactured by growing a negative electrode active material or the like on the negative electrode current collector by a vapor phase method such as vapor deposition or sputtering.
  • the negative electrode (before lithium pre-doping) is lithium pre-doped as described below to produce the negative electrode of this embodiment.
  • Lithium pre-doping is a means for reducing the large irreversible capacity of the negative electrode active material by occluding lithium in the active material. Lithium pre-doping is classified according to the contact time between the negative electrode active material and lithium. (I) Dope lithium in the state of the negative electrode active material powder or negative electrode slurry before the negative electrode preparation.
  • the lithium pre-doping prior to the preparation of the negative electrode includes lithium metal, an organic lithium compound, lithium hydride, lithium aluminum hydride and the like (preferably lithium hydride and hydrogen) in the state of negative electrode active material powder or negative electrode slurry.
  • a doping agent lithium aluminum phosphide
  • a method of doping lithium preferably by heating for example, Patent Document 5 and Patent Document 6 may be mentioned.
  • the pre-doping performed between the preparation of the negative electrode and before the preparation of the electrode body is a state in which only the negative electrode is formed at a time before the electrode body in which the negative electrode, the positive electrode, and the separator are combined by winding or stacking.
  • Lithium pre-doping is preferably performed in a state where the negative electrode is in an electrode plate state.
  • (ii-1) a method in which a negative electrode and a lithium source are arranged in an electrolytic solution, and lithium is doped by a potential difference between the electrode and the lithium source, and (ii-2) an electrode and a lithium source are used.
  • doping in a lithium state by diffusing lithium by heat There is a method of doping in a lithium state by diffusing lithium by heat.
  • the (iii) pre-doping performed during the preparation of the electrode body is, for example, a lithium metal foil on at least one surface, preferably both surfaces of the negative electrode covered with the negative electrode active material when laminating the negative electrode, the positive electrode, and the separator. And a method of laminating the lithium source.
  • the negative electrode constituting the electrode body has two or more layers, it is sufficient that at least one of the surfaces of the negative electrode covered with the negative electrode active material is in contact with the lithium source.
  • a lithium source is laminated on both sides of all the negative electrodes to be formed. Thereafter, heating may be carried out to dope lithium, and this electrode body in the secondary battery touches the electrolyte to form a kind of local battery, which self-discharges and electrochemically lithium is the negative electrode active material. To be doped.
  • the (iv) pre-doping performed after the electrode body is manufactured is preferably performed in a step of completing the secondary battery by enclosing the electrode body and the electrolytic solution in the exterior body after the electrode body is manufactured. And a method of laminating a lithium source such as a lithium metal foil on the outermost negative electrode.
  • the electrode body touches the electrolyte in the secondary battery to form a kind of local battery, self-discharges, and lithium is doped electrochemically into the negative electrode active material. Moreover, you may advance dope by a heat
  • the invention of the present embodiment can be applied to any method that involves a treatment in which a lithium source and a negative electrode active material are brought into direct contact with each other in the lithium pre-dope.
  • the method is preferably applied to the methods (ii-2), (iii) and (iv).
  • the present embodiment will be described taking the method (ii-2) as an example, but the present embodiment is also effective in other methods.
  • the lithium source brought into contact with the negative electrode is preferably made of a metal containing 80% by mass or more of lithium.
  • the metal containing 80% by mass or more of lithium may be a lithium alloy, but the lithium content is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and most preferably Pure lithium metal.
  • metal elements other than lithium contained in the metal having lithium as a main component include sodium, magnesium, silicon, calcium, copper, and cesium.
  • the form of the metal containing 80% by mass or more of lithium may be an arbitrary form such as a foil or piece, but preferably has a larger area that can be in contact with the negative electrode.
  • the lithium metal foil can be manufactured by, for example, extrusion or rolling. It can also be produced by vapor deposition.
  • the lithium metal foil may be in the form of a single foil, or may be in a form in which the lithium metal foil is formed on the substrate 12 as shown in FIG.
  • the substrate metal foil that does not alloy with lithium such as copper, polyester such as polyethylene terephthalate (PET), plastic film such as polypropylene (PP), and the like are used.
  • the base material has flexibility capable of being in close contact with the electrode.
  • the electrode This has the effect of relaxing the shape change. Therefore, for example, the copper foil preferably has a thickness of 10 ⁇ m to 40 ⁇ m.
  • a metal containing 80% by mass or more of lithium is highly reactive, and its surface generates oxides, nitrides, and other lithium reaction products depending on the manufacturing environment, storage environment, and working environment. Further, it is difficult to keep the surface in a pure lithium state because there is a possibility that a surfactant during production is likely to remain. Further, since the reaction generated by these proceeds even in an environment with a low dew point atmosphere, the lithium source is made of nitride, oxide, or other reaction product on the surface of the lithium metal 9 as shown in FIG. There is a non-uniform surface layer 11.
  • lithium oxides and nitrides have different characteristics such as ionic conductivity and different reactions to heat and pressure.
  • lithium carbonate or the like has a lower ionic conductivity than lithium nitride and is disadvantageous for electric conduction, so that it is necessary to suppress diffusion into the electrode.
  • the non-uniform (composition and morphology) surface layer formed on the surface of the lithium metal Due to the non-uniform (composition and morphology) surface layer formed on the surface of the lithium metal, the uniformity and reproducibility of the contact interface between the negative electrode and the lithium source, and non-uniform pre-doping to the negative electrode occur. As a result, there arises a problem that a sufficient amount of lithium cannot be doped, or that more than the required amount of lithium is doped, causing dendrites to occur. Furthermore, unstable lithium pre-doping for the negative electrode reduces the effect of pre-doping on the energy density, cycle characteristics, etc. of the secondary battery.
  • the present inventor made a negative electrode doped with a uniform and sufficient amount of lithium by performing lithium pre-doping by bringing a lithium source having a predetermined surface layer into contact with the negative electrode active material. It has been found that it can be produced.
  • the lithium source used for lithium doping of the negative electrode has a surface layer 10 containing 30% by mass or more of lithium nitride, as shown in FIGS. That is, the method for manufacturing a lithium ion secondary battery according to this embodiment includes a step of bringing a lithium source having a surface layer containing 30% by mass or more of lithium nitride into contact with the negative electrode active material.
  • the surface layer containing 30% by mass or more of lithium nitride may be referred to as “a surface layer mainly containing lithium nitride”.
  • the lithium source is preferably a metal containing 80% by mass or more of lithium as already described, and the form thereof is an arbitrary form such as a foil or a piece, preferably a foil.
  • the lithium source shown in FIG. 2 is a single foil of lithium metal, and has a surface layer 10 mainly containing lithium nitride on both surfaces of the lithium metal 9.
  • the lithium source shown in FIG. 3 has a surface layer 10 mainly containing lithium nitride on the surface of the lithium metal 9 formed on the substrate 12 (on the side opposite to the substrate).
  • the thickness of the surface layer 10 is preferably 30% or less of the thickness of the lithium source. Desirably, the thickness of the surface layer 10 is preferably 3 ⁇ m or less and / or 20% or less of the thickness of the lithium source. It is particularly desirable that the thickness of the surface layer 10 is 1 ⁇ m or less and / or 10% or less of the thickness of the lithium source.
  • the "thickness" to the contact surface between the lithium source and the negative electrode the thickness in the vertical direction.
  • the thickness of the lithium source is not particularly limited, and may be 20 mm or less, for example, 5 mm or less, and preferably about 1 mm or less. In particular, when the lithium source is in the form of a foil, the thickness of the foil is more preferably 500 ⁇ m or less. Further, the thickness of the lithium source is usually preferably 1 ⁇ m or more, more preferably 3 ⁇ m or more, and further preferably 5 ⁇ m or more.
  • the thickness of the lithium source is not particularly limited, but is preferably adjusted according to the composition and thickness of the negative electrode.
  • a lithium source whose surface layer 10 has a thickness in the above range, non-uniformity at the contact interface between the electrode and the lithium source is improved.
  • the surface layer is pierced by irregularities on the surface of the negative electrode, so that the ratio of contact between the lithium metal portion below the surface layer and the negative electrode is particularly preferable.
  • the surface layer of the lithium source is an impurity layer formed by reaction of lithium metal, it is originally preferred that the surface layer is extremely thin.
  • the surface layer of the lithium source needs to be uniform on the surface of the lithium source, it is at least 0.03 ⁇ m or more. It is preferable that it is the thickness of this.
  • the surface layer 10 mainly containing lithium nitride contains lithium nitride in an amount of 40% by mass or more, more preferably 50% by mass or more. Since lithium nitride has a higher ionic conductivity (about 6 mS / cm) than lithium carbonate or the like, the electrical conductivity of the surface layer is improved by increasing the proportion of the surface in the surface layer. Moreover, even when it is taken into the electrode in the state of lithium nitride, the possibility of deteriorating the conductivity of the electrode is low. In particular, when the amount of lithium pre-doping is small, the proportion of lithium nitride in the surface layer is preferably 70% by mass or more.
  • a substance having an ionic conductivity lower than that of lithium nitride such as lithium oxide and lithium carbonate, is not included as much as possible.
  • the content of these substances having low ionic conductivity is preferably 20% by mass or less, and more preferably 10% by mass or less. More preferably, it is 1 mass% or less.
  • a method for forming a surface layer mainly containing lithium nitride on the surface of the lithium source is not particularly limited.
  • a method is generally used in which lithium metal is reacted with N 2 gas and reacted.
  • the reaction temperature is preferably less than the melting point of lithium (180.5 ° C.), preferably about room temperature (20 ° C.) to about 120 ° C.
  • an ion beam having an ion energy of 50 to 300 eV is operated on a lithium metal surface in an atmosphere containing nitrogen (for example, a mixture of nitrogen and argon).
  • nitrogen for example, a mixture of nitrogen and argon.
  • lithium metal can be thermally deposited to form a surface layer mainly containing lithium nitride on the lithium metal surface.
  • the surface of the lithium source formed a surface layer it is preferable that such impurity layer is not as much as possible there, it is preferable to form a surface layer continuously with forming the lithium source due rolling or deposition.
  • the surface layer can be formed by removing the impurity layer by a physical or chemical method and then contacting with N 2 gas.
  • the negative electrode and the lithium source may be in close contact with each other, and the method is not particularly limited.
  • the method is not particularly limited.
  • the method of pressurizing the superimposed negative electrode and lithium source it is necessary to apply a pressure within a range in which relatively soft lithium does not protrude beyond the electrode. Specifically, 0.5 kgf / cm 2 to 30 kgf / cm A pressure of 2 is preferred. In particular, when the thickness of the lithium source is 100 ⁇ m or less, pressurization of 15 kgf / cm 2 or less is preferable. Further, in order to perform uniform lithium pre-doping in the electrode surface, it is preferable to apply pressure uniformly to the electrode surface.
  • the electrode and the lithium source are arranged in a deformable decompression container such as a bag in a state where the contact can be maintained, and the decompression container of the atmospheric pressure received from the outside is received. While the electrode and the lithium source are pressed against each other due to the deformation, the pressure is reduced within a range where there is no excess gap at the interface.
  • the electrode and lithium may be put in a sealable bag such as a laminate to reduce pressure, and sealed under reduced pressure.
  • the pressure be reduced under a reduced pressure of ⁇ 0.05 MPa to ⁇ 0.1 MPa.
  • the methods (1) and (2) may be combined, and if the contact between the negative electrode and the lithium source is good, it is not necessary to pressurize or depressurize. Since diffusion (doping) from the lithium source to the negative electrode proceeds at the part where the lithium and the electrode are in contact, the contact area between the lithium and the electrode when the lithium negative electrode and the lithium source are in sufficient contact and there is no excess gap The lithium pre-doping tends to proceed uniformly.
  • the temperature at which the negative electrode and the lithium source are heated needs to be within a temperature range in which lithium diffusion proceeds stably and does not exceed the melting point of metallic lithium (180.5 ° C.), for example, from room temperature (20 ° C.). A range of 180 ° C. is preferred. At a temperature exceeding the melting point of metallic lithium, the molten lithium protrudes beyond the electrode and cannot be doped efficiently. In addition, when good contact is obtained by the method of bringing the negative electrode and the lithium source into contact with each other, dope is likely to proceed, and room temperature (20 ° C) to 130 ° C is more preferable. In particular, when the negative electrode and the lithium source are in close contact with each other with no extra space, room temperature (20 ° C.) to 80 ° C. is particularly preferable. Although the heating time depends on the required dope amount and the heating temperature, pre-doping can be generally completed within the range of 1 hour to 100 hours, preferably 2 hours to 12 hours.
  • the heating may be performed while applying pressure while maintaining the close contact between the negative electrode and the lithium source.
  • lithium After completing the required amount of lithium pre-doping, if lithium remains on the electrode, it may be removed. When a lithium foil or the like formed on a substrate is used as a lithium source, it can be easily removed.
  • metallic lithium is a highly reactive metal and reacts violently with moisture. Therefore, it is preferable to carry out the work related to lithium pre-doping in a low-humidity environment, and to suppress deterioration of the lithium source, argon It is preferable to work in a gas atmosphere inert to lithium.
  • the positive electrode 2 It does not specifically limit as the positive electrode 2 with which the laminated electrode body 1 which concerns on this embodiment is equipped, A normal positive electrode for secondary batteries can be used.
  • the positive electrode active material contained in the positive electrode 2 include lithium manganate having a layered structure such as LiMnO 2 and Li x Mn 2 O 2 (0 ⁇ x ⁇ 2) or lithium manganate having a spinel structure; LiCoO 2 , LiNiO 2 or a part of these transition metals replaced with other metals; lithium transition metal oxides with less than half of specific transition metals such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 ; Examples of these lithium transition metal oxides include those in which Li is excessive in comparison with the stoichiometric composition.
  • the positive electrode active material contained in the positive electrode one kind may be used alone, or two or more kinds may be used in combination.
  • the positive electrode 2 As a method for producing the positive electrode 2, for example, at least a positive electrode active material, a conductivity imparting agent, and a binder are dispersed and kneaded in a solvent such as N-methyl-2-pyrrolidone that can dissolve the binder.
  • a positive electrode slurry is prepared.
  • the binder the same as the negative electrode can be used.
  • the positive electrode slurry can be prepared by applying the positive electrode slurry onto a positive electrode current collector such as aluminum and drying the solvent. Further, the porosity may be adjusted by pressing the dried positive electrode.
  • the positive electrode current collector the same as the negative electrode current collector can be used.
  • the positive electrode may be manufactured by growing a positive electrode active material or the like on the positive electrode current collector by a vapor phase method such as vapor deposition or sputtering.
  • Examples of the material of the negative electrode lead terminal 7 and the positive electrode lead terminal 7 according to the present embodiment include Al, Cu, Ni, Ti, Fe, phosphor bronze, brass, and stainless steel. These may be used alone or in combination of two or more or as an alloy.
  • the negative electrode lead terminal 4 and the positive electrode lead terminal 5 may be annealed.
  • a normal secondary battery separator can be used.
  • a woven fabric, a nonwoven fabric, a porous film, etc. can be used.
  • polypropylene, polyethylene, and a polyamide-based porous film having a molecular skeleton made of aromatic are preferable from the viewpoints of thinning and large area, and film strength and film resistance.
  • the surface of the separator 4 may be coated with an oxide such as aluminum oxide.
  • the separator 4 what laminated
  • the electrolytic solution used in the present embodiment is not particularly limited, and a normal secondary battery electrolytic solution can be used.
  • a nonaqueous electrolytic solution in which a lithium salt is dissolved as an electrolyte in a nonaqueous solvent can be used.
  • lithium salt examples include LiPF 6 , LiAsF 6 , LiAlCl 4 , LiClO 4 , LiBF 4 , LiSbF 6 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 , LiN (CF 3 SO 2) 2, LiN (SO 2 F) 2 and the like.
  • the lithium salt as the supporting salt is preferably LiPF 6 or LiBF 4 . These supporting salts may be used alone or in combination of two or more.
  • non-aqueous solvent examples include at least one selected from the group consisting of cyclic carbonates, chain carbonates, aliphatic carboxylic acid esters, cyclic ethers, chain ethers, ⁇ -lactones, and derivatives thereof.
  • the above organic solvents are mentioned.
  • Specific examples of the cyclic carbonates include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), and derivatives thereof.
  • chain carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (MEC), dipropyl carbonate (DPC), and derivatives thereof.
  • aliphatic carboxylic acid esters include methyl formate, methyl acetate, ethyl propionate, and derivatives thereof.
  • cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran and the like.
  • chain ethers include 1,2-ethoxyethane (DEE), ethoxymethoxyethane (EME), diethyl ether, and derivatives thereof.
  • DEE 1,2-ethoxyethane
  • EME ethoxymethoxyethane
  • diethyl ether and derivatives thereof.
  • non-aqueous solvents include dimethyl sulfoxide, formamide, acetamide, dimethylformamide, dioxolane such as 1,3-dioxolane, dioxolane derivatives, acetonitrile, propylnitrile, nitromethane, ethyl monoglyme, phosphate triester, Trimethoxymethane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxozolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ethyl ether, 1,3-propane sultone, anisole, N- Examples thereof include methyl pyrrolidone and fluorinated carboxylic acid esters. These non-aqueous solvents may be used alone or in combination of two or more.
  • an ionic liquid can be used as the electrolytic solution.
  • the ionic liquid include quaternary ammonium-imide salts.
  • phosphate ester can also be used as electrolyte solution. Examples of the phosphate ester include triethyl phosphate.
  • a solid electrolyte may be used instead of a liquid electrolyte.
  • a gel electrolyte may be used.
  • the exterior body according to the present embodiment is stable to the electrolytic solution, and has a sufficient barrier property against water vapor, if further electrolyte as it can seal the laminated electrode body 1 without leaking, and in particular Without being limited, a laminate outer body such as a laminate film, a metal can, or the like can be used.
  • a laminate film such as polyethylene coated with aluminum or silica can be used as the outer package.
  • Example 1 [Production of negative electrode] SiO (trade name: “SIO19PB”, High-Purity Chemical Research Laboratory), carbon black (trade name: “# 3030B”, manufactured by Mitsubishi Chemical Corporation), and polyamic acid (trade name: “U-Varnish”) A ”and Ube Industries, Ltd.) were weighed at a mass ratio of 75: 5: 20, respectively. These and n-methylpyrrolidone (NMP) were mixed using a homogenizer to form a slurry. The mass ratio of NMP to solid content was 57:43. The slurry was applied onto a copper foil using a doctor blade. Then, it heated at 120 degreeC for 7 minute (s), and dried NMP. Then, it heated at 350 degreeC for 1 hour using the electric furnace in nitrogen atmosphere, and produced the negative electrode.
  • NMP n-methylpyrrolidone
  • Lithium pre-dope A lithium foil having a thickness of 20 ⁇ m was prepared as a lithium source. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 0.1 ⁇ m covers 90% or more of the lithium foil surface.
  • the lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa.
  • the aluminum laminate bag was heat-treated at 100 ° C. for 24 hours in a thermostatic bath. After the heat treatment was completed, the electrode was taken out from the bag after the aluminum laminate bag was completely returned to room temperature (23 ° C.) or lower, and lithium pre-doping was completed.
  • all lithium sources were doped in the electrode after the heat treatment.
  • Lithium transition metal oxide LiNi 0.80 Co 0.15 Al 0.15 O 2
  • carbon black as a conductivity imparting agent
  • polyvinylidene fluoride as a positive electrode binder
  • the produced laminated electrode element was wrapped with an aluminum laminate film as an outer package, and an electrolytic solution was injected therein, and then sealed in a state where the pressure was reduced to 0.1 atm. Thus, a secondary battery was produced.
  • Example 2 [Preparation of negative electrode] A negative electrode was produced in the same manner as in Example 1.
  • Lithium pre-dope A lithium foil having a thickness of 20 ⁇ m was prepared as a lithium source. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 ⁇ m covers 90% or more of the lithium foil surface.
  • the lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa.
  • the aluminum laminate bag was heat-treated at 100 ° C. for 24 hours in a thermostatic bath. After the heat treatment was completed, the electrode was taken out from the bag after the aluminum laminate bag was completely returned to room temperature (23 ° C.) or lower, and lithium pre-doping was completed.
  • all lithium sources were doped in the electrode after the heat treatment.
  • a positive electrode was produced in the same manner as in Example 1.
  • a secondary battery was fabricated in the same manner as in Example 1.
  • the fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
  • Example 3 [Preparation of negative electrode] A negative electrode was produced in the same manner as in Example 1.
  • Lithium pre-dope As a lithium source, a 20 ⁇ m thick lithium foil formed on a 15 ⁇ m copper foil (base material) was prepared. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 ⁇ m covers 90% or more of the lithium foil surface.
  • the lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa. It was then subjected to heat treatment 100 ° C. 24 hours aluminum laminated bag in a thermostat. After the heat treatment was completed, after the aluminum laminate bag was completely returned to room temperature (23 ° C.) or lower, the electrode was taken out from the bag and the copper foil as the base material of the lithium source was removed to complete the lithium pre-doping. In the negative electrode produced in this example, all lithium sources were doped in the electrode after the heat treatment.
  • a positive electrode was produced in the same manner as in Example 1.
  • a secondary battery was fabricated in the same manner as in Example 1.
  • the fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
  • Example 4 [Preparation of negative electrode] A negative electrode was produced in the same manner as in Example 1.
  • Lithium pre-dope As a lithium source, a 50 ⁇ m thick lithium foil formed on a 15 ⁇ m copper foil (base material) was prepared. It is a surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 ⁇ m and covers 90% or more of the lithium foil surface.
  • the lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa.
  • the aluminum laminate bag was heat-treated at 100 ° C. for 24 hours in a thermostatic bath. After the heat treatment is completed, after the aluminum laminate bag is completely returned to room temperature (23 ° C.) or lower, the electrode is taken out of the bag, and the copper foil that is the base material of the lithium source and the lithium remaining on the copper foil are removed. Completed pre-doping. In the negative electrode produced in this example, surplus lithium with respect to the doping amount remained on the copper foil of the base material.
  • a positive electrode was produced in the same manner as in Example 1.
  • a secondary battery was fabricated in the same manner as in Example 1.
  • the fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
  • Example 5 [Production of negative electrode] A negative electrode was produced in the same manner as in Example 1.
  • Lithium pre-doping As a lithium source, a 50 ⁇ m thick lithium foil formed on a 15 ⁇ m copper foil (base material) was prepared. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 ⁇ m covers 90% or more of the lithium foil surface.
  • the entire surface of the lithium source and the negative electrode was uniformly pressurized at 5 kgf / cm 2 .
  • the lithium source and the negative electrode that were brought into close contact by pressurization were accommodated in an aluminum laminate bag and sealed under reduced pressure.
  • the aluminum laminate bag was heat-treated at 100 ° C. for 24 hours in a thermostatic bath. After the heat treatment is completed, after the aluminum laminate bag is completely returned to room temperature (23 ° C.) or lower, the electrode is taken out of the bag, and the copper foil that is the base material of the lithium source and the lithium remaining on the copper foil are removed. Completed pre-doping. In the negative electrode produced in this example, surplus lithium with respect to the doping amount remained on the copper foil of the base material.
  • a positive electrode was produced in the same manner as in Example 1.
  • a secondary battery was fabricated in the same manner as in Example 1.
  • the fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
  • Example 6 [Preparation of negative electrode] A negative electrode was produced in the same manner as in Example 1.
  • Lithium pre-dope As a lithium source, a 50 ⁇ m thick lithium foil formed on a 15 ⁇ m copper foil (base material) was prepared. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 ⁇ m covers 90% or more of the lithium foil surface.
  • the entire surface of the lithium source and the negative electrode was uniformly pressurized at 10 kgf / cm 2 .
  • the lithium source and the negative electrode that were brought into close contact by pressurization were accommodated in an aluminum laminate bag and sealed under reduced pressure.
  • the aluminum laminate bag was heat-treated at 100 ° C. for 16 hours in a thermostatic bath. After the heat treatment is completed, after the aluminum laminate bag is completely returned to room temperature (23 ° C.) or lower, the electrode is taken out of the bag, and the copper foil that is the base material of the lithium source and the lithium remaining on the copper foil are removed. Completed pre-doping. In the negative electrode produced in this example, surplus lithium with respect to the doping amount remained on the copper foil of the base material.
  • a positive electrode was produced in the same manner as in Example 1.
  • a secondary battery was fabricated in the same manner as in Example 1.
  • the fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
  • Example 7 [Preparation of negative electrode] A negative electrode was produced in the same manner as in Example 1.
  • Lithium pre-dope As a lithium source, a 50 ⁇ m thick lithium foil formed on a 15 ⁇ m copper foil (base material) was prepared. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 ⁇ m covers 90% or more of the lithium foil surface.
  • the entire surface of the lithium source and the negative electrode was uniformly pressurized at 5 kgf / cm 2 .
  • the lithium source and the negative electrode that were brought into close contact by pressurization were accommodated in an aluminum laminate bag and sealed under reduced pressure.
  • the aluminum laminate bag was heat-treated at 60 ° C. for 24 hours in a thermostatic bath. After the heat treatment is completed, after the aluminum laminate bag is completely returned to room temperature (23 ° C.) or lower, the electrode is taken out of the bag, and the copper foil that is the base material of the lithium source and the lithium remaining on the copper foil are removed. Completed pre-doping. In the negative electrode produced in this example, surplus lithium with respect to the doping amount remained on the copper foil of the base material.
  • a positive electrode was produced in the same manner as in Example 1.
  • a secondary battery was fabricated in the same manner as in Example 1.
  • the fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
  • Lithium pre-dope A lithium foil having a thickness of 20 ⁇ m was prepared as a lithium source. On the surface of the lithium foil, which is mainly the surface layer having a thickness of about 2 ⁇ m consisting of lithium carbonate and lithium nitride is formed, in the surface layer, the proportion of lithium nitride is 25% by weight, the proportion of lithium carbonate is from about 70 weight %, And the proportion of lithium oxide was about 5%. The surface layer covers 90% or more of the lithium foil surface.
  • the lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa. It was then subjected to heat treatment 100 ° C. 24 hours aluminum laminated bag in a thermostat. After the heat treatment was completed, the electrode was taken out from the bag after the aluminum laminate bag was completely returned to room temperature (23 ° C.) or lower, and lithium pre-doping was completed. In the negative electrode produced in this example, to remove the lithium source left on the electrode after the heat treatment.
  • a positive electrode was produced in the same manner as in Example 1.
  • a secondary battery was fabricated in the same manner as in Example 1.
  • the fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
  • Example 3 it was confirmed that the same effect was obtained even when pre-doping was performed using a lithium source formed on a substrate (Example 3). Further, it was confirmed that the same effect was obtained when the thickness of the lithium source was changed and the lithium source remaining after the lithium pre-doping was removed (Example 4). Furthermore, it was confirmed that the same effect was obtained when the lithium source and the electrode were brought into close contact with each other using pressure (Examples 5 and 6). Further, it was confirmed that the same effect can be obtained even if the heating temperature and time are changed in the lithium pre-doping step (Examples 5 to 7).
  • Example 8> [Preparation of negative electrode] After the surface of SiO (trade name: “SIO19PB”, High-Purity Chemical Laboratory Co., Ltd.) is uniformly coated with carbon by chemical vapor deposition (coating amount is about 5/75 by mass with respect to SiO), carbon The coated SiO and polyamic acid (trade name: “U-Varnish A”, manufactured by Ube Industries, Ltd.) were weighed at a mass ratio of 80:20, respectively. These and n-methylpyrrolidone (NMP) were mixed using a homogenizer to form a slurry. The mass ratio of NMP to solid content was 57:43. The slurry was applied onto a copper foil using a doctor blade. Then, it heated at 120 degreeC for 7 minute (s), and dried NMP. Then, it heated at 350 degreeC for 1 hour using the electric furnace in nitrogen atmosphere, and produced the negative electrode.
  • SiO trade name: “SIO19PB”, High-Purity Chemical Laboratory Co., Ltd.
  • Lithium pre-doping was performed in the same manner as in Example 1. The amount of lithium pre-doping was 1.1 mg / cm 2 .
  • a positive electrode was produced in the same manner as in Example 1.
  • a secondary battery was fabricated in the same manner as in Example 1.
  • the fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1.
  • the capacity retention rate was 88%.
  • the secondary battery of the present invention is a secondary battery having high energy density and good cycle characteristics, and is used in all industrial fields that require a power source and industrial fields related to transportation, storage and supply of electrical energy. can do. Specifically, it can be used for a power source of a mobile device, a power source of a moving / transport medium, a backup power source, a solar power generation, a wind power generation, and a power storage facility for storing power generated by the power generation.

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Abstract

A lithium ion secondary battery, which is provided with a multilayer electrode body (1) wherein a positive electrode (2) and a negative electrode (3) containing an active material that is capable of absorbing and desorbing lithium are arranged to face each other, is produced by a method that comprises a step wherein a lithium source having a surface layer that contains 30% by mass or more of lithium nitride is brought into contact with the negative electrode active material. The thus-obtained lithium ion secondary battery has high energy density and good cycle characteristics.

Description

リチウムイオン二次電池の製造方法およびリチウムイオン二次電池Lithium ion secondary battery manufacturing method and lithium ion secondary battery
　本発明は、リチウムイオン二次電池の製造方法、特に製造工程の中で、リチウムプレドープ処理を行う工程を有するリチウムイオン二次電池の製造方法に関する。 The present invention relates to a method for manufacturing a lithium ion secondary battery, and more particularly to a method for manufacturing a lithium ion secondary battery including a step of performing a lithium pre-doping process in the manufacturing process.
　ノート型パソコン、携帯電話、電気自動車などの急速な市場拡大に伴い、高エネルギー密度の二次電池が求められている。高エネルギー密度の二次電池を得る手段として、重量あたりの容量の大きな負極材料を用いる方法が挙げられる。 With the rapid market expansion of notebook computers, mobile phones, electric vehicles, etc., secondary batteries with high energy density are required. Means for obtaining a secondary battery with high energy density, such a method is to use a large negative electrode material volume per weight.
　例えば特許文献１には、容量の大きな負極材料としてシリコン酸化物またはシリケート化合物を二次電池の負極活物質に利用することが開示されている。しかしながら、特許文献１に記載されたシリコンの酸化物を負極活物質に利用した二次電池を４５℃以上で充放電させると、サイクルに伴う容量低下が大きいという問題点があった。 For example, Patent Document 1 discloses that silicon oxide or a silicate compound is used as a negative electrode active material of a secondary battery as a negative electrode material having a large capacity. However, when a secondary battery using the oxide of silicon described in Patent Document 1 as a negative electrode active material is charged and discharged at 45 ° C. or higher, there is a problem that the capacity reduction accompanying the cycle is large.
　上述のような容量低下の原因と考えられる、充放電によるリチウム枯渇を補填する手段として、例えば特許文献２および特許文献３には、非炭素系負極に金属リチウム箔を貼り付け、加熱することで、非炭素系負極にリチウムを拡散させることが開示されている。 As a means for compensating for the lithium depletion due to charging / discharging, which is considered to be the cause of the capacity reduction as described above, for example, in Patent Document 2 and Patent Document 3, metal lithium foil is attached to a non-carbon negative electrode and heated. It is disclosed that lithium is diffused into a non-carbon negative electrode.
　特許文献２に記載された非炭素系負極は、金属リチウム箔を貼り付けて、加熱する方法によりリチウムを活物質に拡散させ、充電前から活物質の粒子がリチウムを十分に吸蔵した状態を作り、充放電時の「リチウム枯渇」の問題を解消する手段としている。 The non-carbon-based negative electrode described in Patent Document 2 is a method in which a lithium metal foil is pasted and diffused into the active material by a heating method so that the active material particles sufficiently occlude lithium before charging. This is a means of solving the problem of “lithium depletion” during charging and discharging.
　特許文献３に記載された二次電池の製造方法として、非炭素系負極の活物質を含む層の表面に、加熱および加圧下でリチウムを主体とする金属膜を接触さることにより、リチウムと負極の活物質とを反応させ、活物質中にリチウムを吸蔵させることで、ケイ素酸化物などの負極活物質が有する大きな不可逆容量を解決する手段としている。 As a method of manufacturing a secondary battery described in Patent Document 3, lithium and a negative electrode are obtained by contacting a metal film mainly composed of lithium under heating and pressure on the surface of a layer containing a non-carbon negative electrode active material. This is a means for solving the large irreversible capacity of the negative electrode active material such as silicon oxide by reacting with the active material and occluding lithium in the active material.
　特許文献４には、リチウムイオンを吸蔵、放出し得る炭素材料粒子、リチウムイオンと合金可能な金属粒子、リチウムイオンを吸蔵、放出し得る酸化物粒子を含む活物質層を備えた二次電池用負極が開示されている。特許文献４に記載された二次電池用負極では、３種類の成分の充放電電位の違いにより、リチウムを吸蔵、放出する際、負極全体としての体積変化を緩和させる効果がある。加えて、リチウム金属を負極表面に成膜する技術が開示されている。特許文献４に記載された二次電池用負極では、活物質層上部にリチウム金属層を設けることで、負極活物質が有する大きな不可逆容量を解決する手段としている。リチウム金属層の形成方法として、融液冷却方式、真空蒸着方式、スパッタリング方式などの他に、リチウム金属を負極表面に貼り合わせ、溶融させることによって成膜する方法が示されている。 Patent Document 4 discloses a secondary battery including an active material layer including carbon material particles that can occlude and release lithium ions, metal particles that can be alloyed with lithium ions, and oxide particles that can occlude and release lithium ions. A negative electrode is disclosed. The negative electrode for a secondary battery described in Patent Document 4 has an effect of relaxing the volume change of the entire negative electrode when lithium is occluded and released due to the difference in charge / discharge potential of the three components. In addition, a technique for forming a lithium metal film on the negative electrode surface is disclosed. In the negative electrode for a secondary battery described in Patent Document 4, a lithium metal layer is provided on the active material layer to provide a means for solving the large irreversible capacity of the negative electrode active material. As a method for forming a lithium metal layer, a method for forming a film by bonding lithium metal to the negative electrode surface and melting it is shown in addition to a melt cooling method, a vacuum deposition method, a sputtering method, and the like.
　特許文献５および特許文献６には、炭素で被覆されたシリコン－シリコン酸化物系複合体粒子にリチウムをドープする技術が開示されている。 Patent Documents 5 and 6 disclose a technique of doping lithium into silicon-silicon oxide composite particles coated with carbon.
　また、特許文献７および特許文献８には、窒化リチウムの製造方法が記載されている。特許文献９には、リチウム金属の表面に窒化リチウム保護膜が形成された負極が記載されている。 Patent Documents 7 and 8 describe a method for producing lithium nitride. Patent Document 9 describes a negative electrode in which a lithium nitride protective film is formed on a lithium metal surface.
特開平６－３２５７６５号公報JP-A-6-325765 特開２００５－３５３５７５号公報JP 2005-353575 A 特開２００７－２１４１０９号公報JP 2007-214109 A 特開２００３－１２３７４０号公報JP 2003-123740 A 特開２０１１－２２２１５１号公報JP 2011-222151 A 特開２０１１－２２２１５３号公報JP 2011-222153 A 特開昭５５－４７２１１号公報JP-A-55-47211 特開２００１－４８５０４号公報JP 2001-48504 A 特開２００４－３１９４８９号公報JP 2004-319489 A
　前述のとおり、特許文献２～４では、リチウム源としてリチウム金属箔またはリチウムを主体とする金属膜などを用いて、電池完成前の負極活物質にリチウムをドープすること、即ち、リチウムプレドープすることが開示されている。しかし、リチウムまたはリチウムを主体とする金属の箔、片または成形品を、プレドープのリチウム源とした場合、電極面内および電極毎およびロット毎でリチウムドープ量が安定しない問題がある。 As described above, in Patent Documents 2 to 4, using a lithium metal foil or a metal film mainly composed of lithium as a lithium source, the negative electrode active material before battery completion is doped with lithium, that is, lithium pre-doped. It is disclosed. However, when lithium or a metal foil, piece, or molded product mainly composed of lithium is used as a pre-doped lithium source, there is a problem that the lithium doping amount is not stable within the electrode surface, for each electrode, and for each lot.
　そのため、リチウムプレドープを実施しても、エネルギー密度やサイクル特性が、充分に向上しない場合がある。 Therefore, even if lithium pre-doping is performed, the energy density and cycle characteristics may not be sufficiently improved.
　本発明は、この問題を解決するために成されたものであり、リチウムプレドープを安定して実施することで、不可逆容量を低減し、高エネルギー密度でサイクル特性が向上したリチウムイオン二次電池を製造する方法を提供することを目的とする。 The present invention has been made to solve this problem, and is a lithium ion secondary battery in which irreversible capacity is reduced, cycle characteristics are improved with high energy density, by stably performing lithium pre-doping. An object of the present invention is to provide a method of producing
　本発明は、リチウムを吸蔵、放出が可能な活物質を含む負極と正極が対向に配置された積層電極体を備えるリチウムイオン二次電池の製造方法であって、
　窒化リチウムを３０％質量以上含む表面層を有するリチウム源を、負極活物質に接触させる工程を有することを特徴とするリチウムイオン二次電池の製造方法に関する。 The present invention is a method for producing a lithium ion secondary battery comprising a laminated electrode body in which a negative electrode and a positive electrode containing an active material capable of inserting and extracting lithium are arranged opposite to each other,
The present invention relates to a method for manufacturing a lithium ion secondary battery, comprising a step of bringing a lithium source having a surface layer containing 30% by mass or more of lithium nitride into contact with a negative electrode active material.
　本発明に係る実施形態によれば、高エネルギー密度で、かつサイクル特性が良好な二次電池を提供することができる。 According to the embodiment of the present invention, a secondary battery having a high energy density and good cycle characteristics can be provided.
本実施形態に係る二次電池が有する積層電極素子の一例を模式的に示す断面図である。An example of a laminated electrode elements included in the secondary battery according to the present embodiment is a cross-sectional view schematically showing. 本実施形態に係るリチウムプレドープに用いるリチウム源の一例を模式的に示す断面図である。An example of a lithium source used in the lithium pre-doping of the present embodiment is a cross-sectional view schematically showing. 本実施形態に係るリチウムプレドープに用いる基材を有するリチウム源の一例を模式的に示す断面図である。It is sectional drawing which shows typically an example of the lithium source which has a base material used for the lithium pre dope concerning this embodiment. 従来のリチウムプレドープに用いるリチウム源の一例を模式的に示す断面図である。It is sectional drawing which shows typically an example of the lithium source used for the conventional lithium pre dope.
　本明細書において、リチウムプレドープとは、電池作製後の充電によらずに負極活物質にリチウムを吸蔵させること（リチウムをドープすること）であり、典型的には、電池完成前の工程において、負極活物質にリチウムを吸蔵させること（リチウムをドープすること）を意味する。 In the present specification, the lithium pre-doping means that the negative electrode active material occludes lithium (doping with lithium) regardless of the charge after the battery is manufactured. Typically, in the process before the battery is completed. Means that the negative electrode active material occludes lithium (dope lithium).
　次に、本発明の実施の形態について、詳細に説明する。 Next, embodiments of the present invention will be described in detail.
　［二次電池］
　本実施形態に係る二次電池は、少なくとも一対の正極および負極が対向に配置された電極体と、電解液が外装体に内包される。二次電池の形状は、円筒型、扁平捲回角型、積層角型、コイン型、扁平捲回ラミネート型、および積層ラミネート型のいずれでもよいが、積層ラミネート型が好ましい。以下、積層ラミネート型の二次電池について説明する。 [Secondary battery]
In the secondary battery according to the present embodiment, an electrode body in which at least a pair of a positive electrode and a negative electrode are arranged to face each other, and an electrolytic solution are included in the exterior body. The shape of the secondary battery may be any of a cylindrical type, a flat wound square type, a laminated square type, a coin type, a flat wound laminated type, and a laminated laminate type, and a laminated laminate type is preferable. Hereinafter, a laminated laminate type secondary battery will be described.
　図１に、積層ラミネート型の二次電池が有する積層電極体１の一例の模式的な断面図を示す。複数の正極２および複数の負極３がセパレータ４を挟みつつ交互に積み重ねられている。各正極２および各負極３の一端において、それぞれ正極集電体５、負極集電体６が活物質に覆われていない活物質未塗布部分が設けられている。正極２および負極３は、該活物質未塗布部分を互いに反対向きにして重ねられている。 FIG. 1 shows a schematic cross-sectional view of an example of a laminated electrode body 1 included in a laminated laminate type secondary battery. A plurality of positive electrodes 2 and a plurality of negative electrodes 3 are alternately stacked with the separator 4 interposed therebetween. At one end of each positive electrode 2 and each negative electrode 3, an active material uncoated portion where the positive electrode current collector 5 and the negative electrode current collector 6 are not covered with the active material is provided. The positive electrode 2 and the negative electrode 3 are stacked with the active material uncoated portions facing in opposite directions.
　正極集電体５は、活物質未塗布部分で互いに電気的に接続され、その接続箇所にさらに正極リード端子７が接続されている。負極集電体６は、活物質未塗布部分で互いに電気的に接続され、その接続箇所にさらに負極リード端子８が接続されている。 The positive electrode current collector 5 is electrically connected to each other at an active material uncoated portion, and a positive electrode lead terminal 7 is further connected to the connection portion. The negative electrode current collector 6 is electrically connected to each other at an active material uncoated portion, and a negative electrode lead terminal 8 is further connected to the connection portion.
　積層ラミネート型の二次電池は、積層電極体１をアルミニウムラミネートフィルムなどの外装体で包み、内部に電解液を注液した後、減圧状態で封止することで作製される。 A laminated laminate type secondary battery is manufactured by wrapping a laminated electrode body 1 with an exterior body such as an aluminum laminated film, injecting an electrolyte into the inside, and then sealing under reduced pressure.
　［負極］
　本実施形態に係る積層電極体１に備えられている負極３は、負極活物質と負極用結着剤と負極用集電体とを含み、かつ、二次電池製作前あるいは電極積層前にリチウムをドープされた二次電池用負極である。負極３に含まれる負極活物質としては、特に限定されないが、好ましくは、リチウムと合金可能な金属、リチウムイオンを吸蔵、放出可能な金属酸化物、およびリチウムイオンを吸蔵、放出可能な炭素材料等が挙げられる。本実施形態の活物質としては、これらの１種のみを用いてもよく、２種以上を混合して用いてもよい。 [Negative electrode]
The negative electrode 3 provided in the laminated electrode body 1 according to the present embodiment includes a negative electrode active material, a negative electrode binder, and a negative electrode current collector, and lithium before the production of the secondary battery or before electrode lamination. Is a negative electrode for a secondary battery doped with Although it does not specifically limit as a negative electrode active material contained in the negative electrode 3, Preferably, the metal which can be alloyed with lithium, the metal oxide which can occlude and discharge | release lithium ion, the carbon material which can occlude and discharge | release lithium ion, etc. Is mentioned. As an active material of this embodiment, only 1 type of these may be used, and 2 or more types may be mixed and used.
　リチウムと合金可能な金属としては、Ａｌ、Ｓｉ、Ｐｂ、Ｓｎ、Ｉｎ、Ｂｉ、Ａｇ、Ｂａ、Ｃａ、Ｈｇ、Ｐｄ、Ｐｔ、Ｔｅ、Ｚｎ、Ｌａ、または、これらの二種以上の合金が挙げられる。特に、リチウムと合金可能な金属としてシリコン（Ｓｉ）を含むことが好ましい。負極活物質中の金属の含有率は、５質量％以上９５質量％以下とすることが好ましく、１０質量％以上９０質量％以下とすることがより好ましく、２０質量％以上５０質量％以下とすることがさらに好ましい。 Examples of metals that can be alloyed with lithium include Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, and alloys of two or more of these. It is done. In particular, silicon (Si) is preferably included as a metal that can be alloyed with lithium. The metal content in the negative electrode active material is preferably 5% by mass to 95% by mass, more preferably 10% by mass to 90% by mass, and more preferably 20% by mass to 50% by mass. More preferably.
　リチウムイオンを吸蔵、放出可能な金属酸化物としては、酸化アルミニウム、酸化シリコン、酸化スズ、酸化インジウム、酸化亜鉛、酸化リチウム、または、これらの複合物が挙げられる。特に、リチウムイオンを吸蔵、放出可能な金属酸化物として酸化シリコンを含むことが好ましい。また、金属酸化物に窒素、ホウ素、リンおよびイオウの中から選ばれる一種または二種以上の元素を添加することもできる。こうすることで、金属酸化物の電気伝導性を向上させることができる。負極活物質中の金属酸化物の含有率は、０質量％でも１００質量％でも構わないが、５質量％以上１００質量％以下とすることが好ましく、４０質量％以上９５質量％以下とすることがより好ましく、５０質量％以上９０質量％以下とすることがさらに好ましい。 Examples of metal oxides that can occlude and release lithium ions include aluminum oxide, silicon oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, and composites thereof. In particular, silicon oxide is preferably included as a metal oxide capable of inserting and extracting lithium ions. In addition, one or more elements selected from nitrogen, boron, phosphorus and sulfur can be added to the metal oxide. By carrying out like this, the electrical conductivity of a metal oxide can be improved. The content of the metal oxide in the negative electrode active material may be 0% by mass or 100% by mass, but is preferably 5% by mass or more and 100% by mass or less, and 40% by mass or more and 95% by mass or less. Is more preferable, and it is further more preferable to set it as 50 to 90 mass%.
　また、これらの金属酸化物は、その全部または一部がアモルファス構造を有することが好ましい。金属酸化物がアモルファス構造を有することで、リチウムと合金可能な金属やリチウムイオンを吸蔵、放出可能な炭素材料などの他の負極活物質の体積変化を抑制したり、電解液の分解を抑制したりすることができる。このメカニズムは明確ではないが、金属酸化物がアモルファス構造であることにより、炭素材料と電解液の界面への皮膜形成に何らかの影響があるものと推定される。また、アモルファス構造は、結晶粒界や欠陥といった不均一性に起因する要素が比較的少ないと考えられる。なお、金属酸化物の全部または一部がアモルファス構造を有することは、エックス線回折測定（一般的なＸＲＤ測定）にて確認することができる。具体的には、金属酸化物がアモルファス構造を有しない場合には、金属酸化物に固有のピークが観測されるが、金属酸化物の全部または一部がアモルファス構造を有する場合が、金属酸化物に固有ピークがブロードとなって観測される。 Further, these metal oxides is preferably in whole or in part has an amorphous structure. Since the metal oxide has an amorphous structure, it suppresses volume changes of other negative electrode active materials such as metals that can be alloyed with lithium and carbon materials that can occlude and release lithium ions, and suppresses decomposition of the electrolyte. Can be. Although this mechanism is not clear, it is presumed that the formation of a film on the interface between the carbon material and the electrolytic solution has some influence due to the amorphous structure of the metal oxide. The amorphous structure is considered to have relatively few elements due to non-uniformity such as crystal grain boundaries and defects. It can be confirmed by X-ray diffraction measurement (general XRD measurement) that all or part of the metal oxide has an amorphous structure. Specifically, when the metal oxide does not have an amorphous structure, a peak specific to the metal oxide is observed. However, the metal oxide may have a case where all or part of the metal oxide has an amorphous structure. Inherent peaks are broad and observed.
　また、負極活物質が、リチウムと合金可能な金属およびリチウムイオンを吸蔵、放出可能な金属酸化物を含む場合、合金可能な金属はその全部または一部が金属酸化物中に分散していることが好ましい。こうすることで、負極全体としての体積変化を抑制することができ、電解液の分解も抑制することができる。なお、金属の全部または一部が金属酸化物中に分散していることは、透過型電子顕微鏡観察（一般的なＴＥＭ観察）とエネルギー分散型Ｘ線分光法測定（一般的なＥＤＸ測定）を併用することで確認することができる。具体的には、金属粒子を含むサンプルの断面を観察し、金属酸化物中に分散している金属粒子の酸素濃度を測定し、金属粒子を構成している金属が酸化物となっていないことを確認することができる。 In addition, when the negative electrode active material contains a metal that can be alloyed with lithium and a metal oxide that can occlude and release lithium ions, all or a part of the alloyable metal is dispersed in the metal oxide. Is preferred. By carrying out like this, the volume change as the whole negative electrode can be suppressed, and decomposition | disassembly of electrolyte solution can also be suppressed. Note that all or part of the metal is dispersed in the metal oxide because transmission electron microscope observation (general TEM observation) and energy dispersive X-ray spectroscopy measurement (general EDX measurement). It can confirm by using together. Specifically, the cross section of the sample containing metal particles is observed, the oxygen concentration of the metal particles dispersed in the metal oxide is measured, and the metal constituting the metal particles is not an oxide. Can be confirmed.
　さらに、負極活物質が金属および金属酸化物を含む場合、金属酸化物は、金属を構成する金属の酸化物であることが好ましい。 Furthermore, when the negative electrode active material includes a metal and a metal oxide, the metal oxide is preferably an oxide of a metal constituting the metal.
　負極活物質が金属と金属酸化物とを含む場合、金属および金属酸化物の割合に特に制限はない。金属は、金属および金属酸化物の合計に対し、５質量％以上９０質量％以下とすることが好ましく、３０質量％以上６０質量％以下とすることが好ましい。金属酸化物は、金属および金属酸化物の合計に対し、１０質量％以上９５質量％以下とすることが好ましく、４０質量％以上７０質量％以下とすることが好ましい。 If the negative electrode active material containing a metal and a metal oxide is not particularly limited to the proportion of metals and metal oxides. The metal is preferably 5% by mass or more and 90% by mass or less, and more preferably 30% by mass or more and 60% by mass or less, based on the total of the metal and the metal oxide. The metal oxide is preferably 10% by mass or more and 95% by mass or less, and more preferably 40% by mass or more and 70% by mass or less, with respect to the total of the metal and the metal oxide.
　リチウムイオンを吸蔵、放出可能な炭素材料としては、黒鉛、非晶質炭素、ダイヤモンド状炭素、カーボンナノチューブ、およびこれらの複合物が挙げられる。これらのうち黒鉛は、結晶性が高く、また電気伝導性が高く、銅などの金属からなる集電体との接着性および電圧の平坦性に優れている。また、非晶質炭素は、結晶性が低く、体積変化が比較的小さいため、負極全体の体積変化を緩和することができ、かつ結晶粒塊や欠陥などの不均一性に起因する劣化を生じにくい。負極活物質中の炭素材料の含有率は、０質量％でも構わないが、１質量％以上５０質量％以下とすることが好ましく、２質量％以上３０質量％以下とすることがより好ましい。 Examples of carbon materials that can occlude and release lithium ions include graphite, amorphous carbon, diamond-like carbon, carbon nanotubes, and composites thereof. Among these, graphite has high crystallinity, high electrical conductivity, and excellent adhesion to a current collector made of a metal such as copper and voltage flatness. Amorphous carbon has low crystallinity and a relatively small volume change, so that the volume change of the entire negative electrode can be mitigated, and deterioration due to nonuniformity such as crystal agglomerates and defects occurs. Hateful. The content of the carbon material in the negative electrode active material may be 0% by mass, but is preferably 1% by mass to 50% by mass, and more preferably 2% by mass to 30% by mass.
　負極活物質が、リチウムと合金可能な金属、およびリチウムイオンを吸蔵、放出可能な金属酸化物、およびリチウムイオンを吸蔵、放出可能な炭素材料を含む場合、これらの割合に特に制限はない。金属は、金属、金属酸化物および炭素材料の合計に対し、５質量％以上９０質量％以下とすることが好ましく、２０質量％以上５０質量％以下とすることが好ましい。金属酸化物は、金属、金属酸化物および炭素材料の合計に対し、５質量％以上９０質量％以下とすることが好ましく、４０質量％以上７０質量％以下とすることが好ましい。炭素材料は、金属、金属酸化物および炭素材料の合計に対し、１質量％以上５０質量％以下とすることが好ましく、２質量％以上３０質量％以下とすることが好ましい。 When the negative electrode active material contains a metal that can be alloyed with lithium, a metal oxide that can occlude and release lithium ions, and a carbon material that can occlude and release lithium ions, these ratios are not particularly limited. The metal is preferably 5% by mass or more and 90% by mass or less, and more preferably 20% by mass or more and 50% by mass or less with respect to the total of the metal, the metal oxide, and the carbon material. The metal oxide is preferably 5% by mass or more and 90% by mass or less, and more preferably 40% by mass or more and 70% by mass or less with respect to the total of the metal, the metal oxide, and the carbon material. The carbon material is preferably 1% by mass or more and 50% by mass or less, and more preferably 2% by mass or more and 30% by mass or less with respect to the total of the metal, the metal oxide, and the carbon material.
　また、金属、金属酸化物および炭素材料は、特に制限するものではないが、それぞれ粒子状のものを用いることができる。例えば、金属の平均粒子径は、金属酸化物の平均粒子径および炭素材料の平均粒子径よりも小さい構成とすることができる。このようにすれば、充放電時に伴う体積変化の大きい金属が相対的に小粒径となり、体積変化の小さい金属酸化物や炭素材料が相対的に大粒径となるため、デンドライト生成および合金の微粉化がより効果的に抑制される。また、充放電の過程で大粒径の粒子、小粒径の粒子、大粒径の粒子の順にリチウムが吸蔵、放出されることとなり、この点からも、残留応力、残留歪みの発生が抑制される。金属の平均粒子径は、例えば１０μｍ以下とすることができ、５μｍ以下とすることが好ましい。 The metal, metal oxide, and carbon material are not particularly limited, but particulate materials can be used. For example, the average particle size of the metal can be smaller than the average particle size of the metal oxide and the average particle size of the carbon material. In this way, metals with a large volume change during charge / discharge have a relatively small particle size, and metal oxides and carbon materials with a small volume change have a relatively large particle size. Micronization is more effectively suppressed. In addition, lithium is occluded and released in the order of large-diameter particles, small-diameter particles, and large-diameter particles during the charge / discharge process. This also suppresses the occurrence of residual stress and residual strain. Is done. The average particle diameter of the metal can be, for example, 10 μm or less, and is preferably 5 μm or less.
　また、炭素材料は、金属および金属酸化物を被覆する状態で粒子の表面付近に局在化してもよい。このように表面付近に局在化させることにより、金属および金属酸化物の凝集を抑制し、負極全体として体積変化を緩和することができ、さらに電子伝導性の均一化に効果がある。 Further, the carbon material may be localized near the surface of the particle in a state of covering the metal and the metal oxide. By localizing in the vicinity of the surface in this way, the aggregation of the metal and the metal oxide can be suppressed, the volume change of the negative electrode as a whole can be reduced, and further, the electron conductivity can be made uniform.
　負極活物質が金属と金属酸化物と炭素材料とを含み、金属酸化物の全部または一部がアモルファス構造であり、金属の全部または一部が金属酸化物中に分散しており、炭素材料が局在化しているような負極活物質は、例えば、特開２００４－４７４０４号公報で開示されているような方法で作製することができる。すなわち、金属酸化物をメタンガスなどの有機物ガスを含む雰囲気下でＣＶＤ処理を行うことで、金属酸化物中の金属がナノクラスター化し、かつ表面が炭素材料で被覆された複合体を得ることができる。また、金属と金属酸化物と炭素材料とを、段階的にメカニカルミリングで混合することでも、上記負極活物質を作製することができる。 The negative electrode active material includes a metal, a metal oxide, and a carbon material, all or part of the metal oxide has an amorphous structure, all or part of the metal is dispersed in the metal oxide, and the carbon material is A localized negative electrode active material can be produced by a method as disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-47404. That is, by performing a CVD process in an atmosphere containing an organic gas such as methane gas, a metal oxide in which metal in the metal oxide is nanoclustered and a surface is coated with a carbon material can be obtained. . Moreover, the said negative electrode active material is producible also by mixing a metal, a metal oxide, and a carbon material in steps by mechanical milling.
　また、本実施形態において、負極活物質は、シリコンを主体とした負極活物質であることが好ましい。シリコンおよびシリコン酸化物に、後述のようにリチウムプレドープ処理を行うことで、リチウムシリケートを形成することが出来る。その際、シリコンの価数を制御することで、高容量かつ長寿命の負極を作製することができる。具体的には、酸化数が０のシリコンと、酸化数が＋４のシリコン原子を有するシリコン化合物と、酸化数が０より大きく＋４未満のシリコン原子を有するシリコン低級酸化物を形成することで、高容量かつ長寿命の負極を作製することができる。 In the present embodiment, the negative electrode active material is preferably a negative electrode active material mainly composed of silicon. Lithium silicate can be formed by performing lithium pre-doping on silicon and silicon oxide as described later. At that time, by controlling the valence of silicon, a negative electrode having a high capacity and a long life can be produced. Specifically, by forming silicon having an oxidation number of 0, a silicon compound having a silicon atom having an oxidation number of +4, and a silicon lower oxide having a silicon atom having an oxidation number of greater than 0 and less than +4, A negative electrode having a capacity and a long life can be produced.
　さらに、負極活物質を粉末状体でリチウムをドープしてもよく、例えば、特許文献５および特許文献６に記載のような手法により作製することができる。具体的には、粉末状の活物質とリチウム源（例えばリチウム金属、有機リチウム化合物、水素化リチウム、水素化リチウムアルミニウム等が挙げられ、水素化リチウムおよび水素化リチウムアルミニウムが好ましい。）とを、所定のモル比で混合した後、１００℃～８００℃、好ましくは２００℃～８００℃で加熱する。このように、負極活物質を粉末状体でリチウムプレドープした場合であっても、後述する本実施形態のリチウムプレドープ処理（所定の表面層を有するリチウム源を、負極活物質に接触させる工程）を実施することができる。従って、少なくとも２回のリチウムプレドープを実施してもよい。 Furthermore, the negative electrode active material may be doped with lithium in the form of a powder, and for example, it can be produced by the techniques described in Patent Document 5 and Patent Document 6. Specifically, a powdered active material and a lithium source (for example, lithium metal, an organic lithium compound, lithium hydride, lithium aluminum hydride, etc. are mentioned, and lithium hydride and lithium aluminum hydride are preferable). They were mixed in a predetermined molar ratio, 100 ℃ ~ 800 ℃, preferably heated at 200 ℃ ~ 800 ℃. Thus, even when the negative electrode active material is lithium-doped with a powdered body, the lithium pre-doping treatment of the present embodiment described later (a step of bringing a lithium source having a predetermined surface layer into contact with the negative electrode active material) ) Can be implemented. Therefore, lithium pre-doping may be performed at least twice.
　負極用結着剤としては、ポリフッ化ビニリデン、変性ポリフッ化ビニリデン、ビニリデンフルオライド－ヘキサフルオロプロピレン共重合体、ビニリデンフルオライド－テトラフルオロエチレン共重合体、スチレン－ブタジエン共重合ゴム、ポリテトラフルオロエチレン、ポリプロピレン、ポリエチレン、ポリアクリル酸、ポリアクリル酸の金属塩、ポリイミド、ポリアミドイミド等が挙げられる。本実施形態では、ポリイミドまたはポリアミドイミドを含むことが好ましい。使用する負極用結着剤の含有率は、トレードオフの関係にある「十分な結着力」と「高エネルギー化」の観点から、負極活物質の全質量に対し、５～２０質量％が好ましく、８～１５質量％が好ましい。 Negative electrode binders include polyvinylidene fluoride, modified polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer rubber, polytetrafluoroethylene. , Polypropylene, polyethylene, polyacrylic acid, metal salt of polyacrylic acid, polyimide, polyamideimide and the like. In the present embodiment, it is preferable to include polyimide or polyamideimide. The content of the binder for the negative electrode to be used is preferably 5 to 20% by mass with respect to the total mass of the negative electrode active material from the viewpoints of “sufficient binding force” and “high energy” which are in a trade-off relationship. 8 to 15% by mass is preferable.
　負極集電体としては、アルミニウム、ニッケル、銅、銀、およびこれらの合金やステンレスが挙げられる。集電体の形状は、箔、平板、メッシュ状などが挙げられる。 Examples of the negative electrode current collector include aluminum, nickel, copper, silver, alloys thereof, and stainless steel. Examples of the shape of the current collector include a foil, a flat plate, and a mesh.
　負極３の製造方法としては、例えば、負極活物質、導電性付与剤、および結着剤を、Ｎ－メチル－２－ピロリドン（ＮＭＰ）等の溶剤中に分散、混練して負極スラリーを調整する。導電性付与剤としては、カーボンブラック、グラファイト、アセチレンブラック等の炭素質微粒子が挙げられる。負極活物質の表面に予め炭素材料が局材している場合は、導電性付与剤を含まなくても良い。該負極スラリーを銅箔等の負極集電体上に塗布し、溶剤を乾燥することでリチウムプレドープ前の負極を作製することができる。塗布方法としては、ドクターブレード法、ダイコーター法などが挙げられる。予め負極活物質層を形成した後に、蒸着、スパッタ等の方法でアルミニウム、ニッケルまたはそれらの合金の薄膜を形成して、負極集電体としてもよい。また、ポリイミド前駆体やポリアミドイミド前駆体等の、溶剤の乾燥温度以上での熱処理が必要な場合は、必要に応じて所望の熱処理を行うことができる。ポリアミド前駆体やポリイミド前駆体として、ポリアミック酸を含有していることが好ましい。また、負極集電体上に負極活物質等を蒸着やスパッタ等の気相法により成長することで、リチウムプレドープ前の負極を製作してもよい。 As a method for producing the negative electrode 3, for example, a negative electrode active material, a conductivity imparting agent, and a binder are dispersed and kneaded in a solvent such as N-methyl-2-pyrrolidone (NMP) to prepare a negative electrode slurry. . The conductive agent, carbon black, graphite, carbonaceous fine particles such as acetylene black. When the carbon material is previously localized on the surface of the negative electrode active material, the conductivity imparting agent may not be included. A negative electrode before lithium pre-doping can be prepared by applying the negative electrode slurry onto a negative electrode current collector such as a copper foil and drying the solvent. Examples of the coating method include a doctor blade method and a die coater method. After forming a negative electrode active material layer in advance, a thin film of aluminum, nickel, or an alloy thereof may be formed by a method such as vapor deposition or sputtering to form a negative electrode current collector. Moreover, when the heat processing above the drying temperature of a solvent, such as a polyimide precursor and a polyamideimide precursor, is required, desired heat processing can be performed as needed. As the polyamide precursor or a polyimide precursor, preferably it contains the polyamic acid. Alternatively, the negative electrode before lithium pre-doping may be manufactured by growing a negative electrode active material or the like on the negative electrode current collector by a vapor phase method such as vapor deposition or sputtering.
　［リチウムプレドープ］
　次に、負極（リチウムプレドープ前）に、以下に説明するようにリチウムプレドープして、本実施形態の負極を作製する。 [Lithium pre-dope]
Next, the negative electrode (before lithium pre-doping) is lithium pre-doped as described below to produce the negative electrode of this embodiment.
　まず、リチウムプレドープ一般について述べると、リチウムプレドープは、活物質中にリチウムを吸蔵させることで、負極活物質が有する大きな不可逆容量を低減する手段である。リチウムプレドープを、負極活物質とリチウムとの接触時期で分類すると、（ｉ）負極作製前に負極活物質粉末、あるいは負極スラリーの状態でリチウムをドープする、（ｉｉ）負極作製後から電極体作製より前までの間に、金属リチウムあるいはリチウム化合物をリチウム源としてリチウムをドープする、（ｉｉｉ）電極体作製の間に、金属リチウムあるいはリチウム化合物をリチウム源としてリチウムをドープする、（ｉｖ）電極体作製後に、金属リチウムあるいはリチウム化合物をリチウム源としてリチウムをドープする、等に分類される。 First, lithium pre-doping in general will be described. Lithium pre-doping is a means for reducing the large irreversible capacity of the negative electrode active material by occluding lithium in the active material. Lithium pre-doping is classified according to the contact time between the negative electrode active material and lithium. (I) Dope lithium in the state of the negative electrode active material powder or negative electrode slurry before the negative electrode preparation. (Ii) Electrode body after the negative electrode preparation Before the production, dope lithium with metallic lithium or lithium compound as a lithium source, (iii) During the production of the electrode body, dope lithium with metallic lithium or lithium compound as a lithium source, (iv) Electrode after the body produced is doped with lithium as a lithium source metal lithium or a lithium compound, it is classified as equal.
　上記（ｉ）負極作製前におけるリチウムプレドープとしては、負極活物質粉末、あるいは負極スラリーの状態で、リチウム金属、有機リチウム化合物、水素化リチウム、水素化リチウムアルミニウム等（好ましくは水素化リチウムや水素化リチウムアルミニウム）をドープ剤として、好ましくは加熱して、リチウムをドープする方法（例えば、特許文献５および特許文献６）が挙げられる。 (I) The lithium pre-doping prior to the preparation of the negative electrode includes lithium metal, an organic lithium compound, lithium hydride, lithium aluminum hydride and the like (preferably lithium hydride and hydrogen) in the state of negative electrode active material powder or negative electrode slurry. As a doping agent (lithium aluminum phosphide), a method of doping lithium preferably by heating (for example, Patent Document 5 and Patent Document 6) may be mentioned.
　上記（ｉｉ）負極作製後から電極体作製より前までの間に行うプレドープは、捲回あるいは積層によって、負極、正極、およびセパレータが組み合わさった電極体になる前の時期に、負極のみの状態（好ましくは負極が極板状態にある状態）で行うリチウムプレドープのことである。この時期に行うリチウムプレドープとしては、（ｉｉ－１）負極とリチウム源を電解液中に配置し、電極とリチウム源の電位差によりリチウムをドープする方法、（ｉｉ－２）電極とリチウム源を接触させた状態に配置し、熱によるリチウムの拡散によりリチウムをドープする方法が挙げられる。 (Ii) The pre-doping performed between the preparation of the negative electrode and before the preparation of the electrode body is a state in which only the negative electrode is formed at a time before the electrode body in which the negative electrode, the positive electrode, and the separator are combined by winding or stacking. Lithium pre-doping is preferably performed in a state where the negative electrode is in an electrode plate state. As the lithium pre-doping performed at this time, (ii-1) a method in which a negative electrode and a lithium source are arranged in an electrolytic solution, and lithium is doped by a potential difference between the electrode and the lithium source, and (ii-2) an electrode and a lithium source are used. There is a method of doping in a lithium state by diffusing lithium by heat.
　上記（ｉｉｉ）電極体作製の間に行うプレドープは、例えば、負極と正極とセパレータとを積層する際、負極の負極活物質で覆われている面の少なくとも片面、好ましくは両面にリチウム金属箔等のリチウム源を積層する方法が挙げられる。電極体を構成する負極が２層以上あるときは、少なくとも１層の負極の負極活物質で覆われている面のうち片面がリチウム源と接触していればよいが、好ましくは、電極体を構成するすべての負極の両面にリチウム源を積層する。その後、加熱してリチウムのドープを進行させてもよく、また、二次電池内でこの電極体が電解質に触れることにより一種の局部電池を形成し自己放電し電気化学的にリチウムが負極活物質にドープされる。 The (iii) pre-doping performed during the preparation of the electrode body is, for example, a lithium metal foil on at least one surface, preferably both surfaces of the negative electrode covered with the negative electrode active material when laminating the negative electrode, the positive electrode, and the separator. And a method of laminating the lithium source. When the negative electrode constituting the electrode body has two or more layers, it is sufficient that at least one of the surfaces of the negative electrode covered with the negative electrode active material is in contact with the lithium source. A lithium source is laminated on both sides of all the negative electrodes to be formed. Thereafter, heating may be carried out to dope lithium, and this electrode body in the secondary battery touches the electrolyte to form a kind of local battery, which self-discharges and electrochemically lithium is the negative electrode active material. To be doped.
　上記（ｉｖ）電極体作製後に行うプレドープは、電極体を作製した後、好ましくは、電極体と電解液とを外装体内に封入して二次電池を完成する工程において行われ、例えば、電極体の最外層の負極上にリチウム金属箔等のリチウム源を積層する方法が挙げられる。二次電池に組み込まれた後、二次電池内でこの電極体が電解質に触れることにより一種の局部電池を形成し自己放電し電気化学的にリチウムが負極活物質にドープされる。また、熱によりドープを進行させてもよい。 The (iv) pre-doping performed after the electrode body is manufactured is preferably performed in a step of completing the secondary battery by enclosing the electrode body and the electrolytic solution in the exterior body after the electrode body is manufactured. And a method of laminating a lithium source such as a lithium metal foil on the outermost negative electrode. After being incorporated in the secondary battery, the electrode body touches the electrolyte in the secondary battery to form a kind of local battery, self-discharges, and lithium is doped electrochemically into the negative electrode active material. Moreover, you may advance dope by a heat | fever.
　本実施形態の発明は、上記のリチウムプレドープの中で、リチウム源と負極活物質を直接接触させる処理を伴う方法であれば、全て適用可能である。好ましくは（ｉｉ－２）、（ｉｉｉ）および（ｉｖ）の方法に適用される。以下、（ｉｉ－２）の方法を例に本実施形態を説明するが、本実施形態は、他の方法においても有効である。 The invention of the present embodiment can be applied to any method that involves a treatment in which a lithium source and a negative electrode active material are brought into direct contact with each other in the lithium pre-dope. The method is preferably applied to the methods (ii-2), (iii) and (iv). Hereinafter, the present embodiment will be described taking the method (ii-2) as an example, but the present embodiment is also effective in other methods.
　本実施形態において、負極に接触させるリチウム源は、リチウムを８０質量％以上含む金属からなることが好ましい。リチウムを８０質量％以上含む金属は、リチウム合金であってもよいが、リチウムの含有量が好ましくは８０質量％以上、より好ましくは９０質量％以上、さらに好ましくは９５質量％以上、最も好ましくは純リチウム金属である。リチウムを主成分とする金属に含有されるリチウム以外の金属元素としては、例えば、ナトリウム、マグネシウム、シリコン、カルシウム、銅、セシウム等が挙げられる。 In this embodiment, the lithium source brought into contact with the negative electrode is preferably made of a metal containing 80% by mass or more of lithium. The metal containing 80% by mass or more of lithium may be a lithium alloy, but the lithium content is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and most preferably Pure lithium metal. Examples of metal elements other than lithium contained in the metal having lithium as a main component include sodium, magnesium, silicon, calcium, copper, and cesium.
　リチウムを８０質量％以上含む金属（以下、単に、リチウム金属ということがある。）の形態は、箔、片等の任意の形態でよいが、負極と接触できる面積が大きい方が好ましく、箔が好ましい。リチウム金属箔は、例えば、押し出しあるいは圧延により製作することができる。また蒸着により作製することもできる。 The form of the metal containing 80% by mass or more of lithium (hereinafter sometimes simply referred to as lithium metal) may be an arbitrary form such as a foil or piece, but preferably has a larger area that can be in contact with the negative electrode. preferable. The lithium metal foil can be manufactured by, for example, extrusion or rolling. It can also be produced by vapor deposition.
　リチウム金属箔は、それ単独の箔の形態であってよいが、また、図３に示す様に、リチウム金属箔が基材１２上に形成された形態でもよい。基材としては、銅などのリチウムと合金化反応しない金属箔、ポリエチレンテレフタレート（ＰＥＴ）などのポリエステルやポリプロピレン（ＰＰ）等のプラスチックフィルムなどが使用される。基材は、電極に密着可能な柔軟性を有することが好ましいが、一方で、リチウムのドープにより電極に膨張や収縮による体積変化が生じた際にシワ等にならない程度の強度を有すると、電極の形状変化を緩和する効果がある。従って、例えば、銅箔では１０μｍから４０μｍの厚さを有することが好ましい。 The lithium metal foil may be in the form of a single foil, or may be in a form in which the lithium metal foil is formed on the substrate 12 as shown in FIG. As the substrate, metal foil that does not alloy with lithium such as copper, polyester such as polyethylene terephthalate (PET), plastic film such as polypropylene (PP), and the like are used. It is preferable that the base material has flexibility capable of being in close contact with the electrode. On the other hand, if the base material has a strength that does not cause wrinkles or the like when a volume change due to expansion or contraction occurs due to lithium doping, the electrode This has the effect of relaxing the shape change. Therefore, for example, the copper foil preferably has a thickness of 10 μm to 40 μm.
　リチウムを８０質量％以上含む金属は反応性が高く、その表面は製造時の環境、保管環境、および使用時の作業環境によって酸化物、窒化物、および他のリチウムの反応生成物などが生成し易く、さらに製造時の界面活性剤も残留する可能性もあるため、表面を純リチウムの状態に保つことが難しい。また、これらが生成する反応は低露点雰囲気の環境下においても進行することから、図４に示すようにリチウム源は、リチウム金属９の表面に窒化物や酸化物、その他の反応生成物からなる不均一な表面層１１が存在する。 A metal containing 80% by mass or more of lithium is highly reactive, and its surface generates oxides, nitrides, and other lithium reaction products depending on the manufacturing environment, storage environment, and working environment. Further, it is difficult to keep the surface in a pure lithium state because there is a possibility that a surfactant during production is likely to remain. Further, since the reaction generated by these proceeds even in an environment with a low dew point atmosphere, the lithium source is made of nitride, oxide, or other reaction product on the surface of the lithium metal 9 as shown in FIG. There is a non-uniform surface layer 11.
　この表面層１１の組成は、製造方法や使用条件、使用環境、保管環境などにより、大きく異なることが多い。真空装置内で蒸着やスパッタなどによりリチウム膜を形成した場合であっても、蒸着時の真空度や導入ガス、温度などの条件により表面層の生成状態は異なる。また、深さ方向および横方向への分布も使用条件や環境により異なる。 The composition of the surface layer 11, the production method and usage conditions, use environment, and storage environments, often differ greatly. Even when a lithium film is formed by vapor deposition, sputtering, or the like in a vacuum apparatus, the generation state of the surface layer varies depending on conditions such as the degree of vacuum, gas introduced, and temperature during vapor deposition. Further, the distribution in the depth direction and the lateral direction also varies depending on the use conditions and environment.
　さらに、例えば、リチウムの酸化物や窒化物はイオン伝導率などや熱や圧力への反応が異なるなど、その特性も異なる。例えば、炭酸リチウムなどは窒化リチウムに比べてイオン伝導率の低く電気伝導に不利であることから、電極中への拡散を抑制する必要がある。 Furthermore, for example, lithium oxides and nitrides have different characteristics such as ionic conductivity and different reactions to heat and pressure. For example, lithium carbonate or the like has a lower ionic conductivity than lithium nitride and is disadvantageous for electric conduction, so that it is necessary to suppress diffusion into the electrode.
　リチウム金属表面に形成される不均一（組成および形態）な表面層に起因し、負極とリチウム源の接触界面の均一性や再現性におけるばらつき、負極へのプレドープの不均一が生じる。その結果、十分な量のリチウムをドープできない、あるいは必要量以上のリチウムがドープされてデンドライト発生の要因となる等の不具合を生じる。さらに、負極に対する不安定なリチウムプレドープは、二次電池のエネルギー密度やサイクル特性などに対するプレドープの効果を低減する。 Due to the non-uniform (composition and morphology) surface layer formed on the surface of the lithium metal, the uniformity and reproducibility of the contact interface between the negative electrode and the lithium source, and non-uniform pre-doping to the negative electrode occur. As a result, there arises a problem that a sufficient amount of lithium cannot be doped, or that more than the required amount of lithium is doped, causing dendrites to occur. Furthermore, unstable lithium pre-doping for the negative electrode reduces the effect of pre-doping on the energy density, cycle characteristics, etc. of the secondary battery.
　対策として、ガス組成を制御した減圧雰囲気下において負極上へリチウムを直接蒸着する方法、あるいはガス組成を制御した減圧雰囲気下におけるリチウム源製造と、負極へプレドープとの連続プロセスによる方法を採用すれば、表面層の問題は解決可能と考えられるが、実用性に乏しい。 As a countermeasure, if a method of directly depositing lithium on the negative electrode in a reduced pressure atmosphere with a controlled gas composition, or a method using a continuous process of producing a lithium source in a reduced pressure atmosphere with a controlled gas composition and pre-doping on the negative electrode is adopted. The problem of the surface layer is considered to be solvable, but the practicality is poor.
　本発明者は、上記の問題を鋭意検討した結果、所定の表面層を有するリチウム源を負極活物質に接触させてリチウムプレドープを行うことにより、均一で十分な量のリチウムをドープした負極を作製できることを見いだしたものである。 As a result of intensive studies on the above problems, the present inventor made a negative electrode doped with a uniform and sufficient amount of lithium by performing lithium pre-doping by bringing a lithium source having a predetermined surface layer into contact with the negative electrode active material. It has been found that it can be produced.
　本実施形態において、負極へのリチウムドープに用いるリチウム源は、図２および図３に示す様に、窒化リチウムを３０質量％以上含む表面層１０を有する。即ち、本実施形態のリチウムイオン二次電池の製造方法は、窒化リチウムを３０質量％以上含む表面層を有するリチウム源を、負極活物質に接触させる工程を有する。以下、窒化リチウムを３０質量％以上含む表面層を、「窒化リチウムを主として含む表面層」と呼ぶことがある。 In this embodiment, the lithium source used for lithium doping of the negative electrode has a surface layer 10 containing 30% by mass or more of lithium nitride, as shown in FIGS. That is, the method for manufacturing a lithium ion secondary battery according to this embodiment includes a step of bringing a lithium source having a surface layer containing 30% by mass or more of lithium nitride into contact with the negative electrode active material. Hereinafter, the surface layer containing 30% by mass or more of lithium nitride may be referred to as “a surface layer mainly containing lithium nitride”.
　リチウム源は、好ましくはすでに説明したとおりの、リチウムを８０質量％以上含む金属であり、その形態は、箔、片等の任意の形態、好ましくは箔である。図２に示すリチウム源は、リチウム金属の単独の箔であり、リチウム金属９の両面に、窒化リチウムを主として含む表面層１０を有する。ここで、リチウム源が、リチウム金属の単独の箔である場合、リチウム源の少なくとも片面（負極と接触させる面）が、窒化リチウムを主として含む表面層となっていればよいが、図２に示すように、両面が窒化リチウムを主として含む表面層であってもよい。また、図３に示すリチウム源は、基材１２上に形成されたリチウム金属９の表面（基材と反対側）に、窒化リチウムを主として含む表面層１０を有する。 The lithium source is preferably a metal containing 80% by mass or more of lithium as already described, and the form thereof is an arbitrary form such as a foil or a piece, preferably a foil. The lithium source shown in FIG. 2 is a single foil of lithium metal, and has a surface layer 10 mainly containing lithium nitride on both surfaces of the lithium metal 9. Here, when the lithium source is a single foil of lithium metal, it is sufficient that at least one surface of the lithium source (surface to be brought into contact with the negative electrode) is a surface layer mainly containing lithium nitride, as shown in FIG. Thus, the surface layer which mainly contains lithium nitride may be sufficient as both surfaces. The lithium source shown in FIG. 3 has a surface layer 10 mainly containing lithium nitride on the surface of the lithium metal 9 formed on the substrate 12 (on the side opposite to the substrate).
　表面層１０の厚さはリチウム源の厚さの３０％以下であることが好ましい。望ましくは、表面層１０の厚さは３μｍ以下であること、および／またはリチウム源の厚さの２０％以下であることが好ましい。特に望ましくは、表面層１０の厚さが１μｍ以下であること、および／またはリチウム源の厚さの１０％以下であることが好ましい。ここで、「厚さ」とは、リチウム源と負極との接触面に対して、垂直方向における厚さである。リチウム源の厚さは、特に限定されず、例えば２０ｍｍ以下でよく、１例としては５ｍｍ以下、好ましくは１ｍｍ以下程度である。特にリチウム源が箔の形態であるとき、箔の厚さとしては、より好ましくは５００μｍ以下である。また、リチウム源の厚さは、通常では好ましくは１μｍ以上であり、より好ましくは３μｍ以上であり、さらに好ましくは５μｍ以上である。 The thickness of the surface layer 10 is preferably 30% or less of the thickness of the lithium source. Desirably, the thickness of the surface layer 10 is preferably 3 μm or less and / or 20% or less of the thickness of the lithium source. It is particularly desirable that the thickness of the surface layer 10 is 1 μm or less and / or 10% or less of the thickness of the lithium source. Here, the "thickness", to the contact surface between the lithium source and the negative electrode, the thickness in the vertical direction. The thickness of the lithium source is not particularly limited, and may be 20 mm or less, for example, 5 mm or less, and preferably about 1 mm or less. In particular, when the lithium source is in the form of a foil, the thickness of the foil is more preferably 500 μm or less. Further, the thickness of the lithium source is usually preferably 1 μm or more, more preferably 3 μm or more, and further preferably 5 μm or more.
　リチウム源の厚さは、特に限定されないが、負極の組成および厚さよって調整することが好ましい。表面層１０の厚さが上記範囲であるリチウム源を用いることにより、電極とリチウム源の接触界面における不均一性が改善される。特に０．５μｍ以下の薄い表面層の場合には、負極表面の凹凸によって表面層を突き破るため、表面層より下のリチウム金属部分と負極とが接触する割合が増加するため、特に好ましい。リチウム源の表面層は、リチウム金属が反応して形成された不純物層であるため、本来は極めて薄いことが好まれるが、リチウム源の表面で均一であることが必要なため少なくとも０．０３μｍ以上の厚さであることが好ましい。 The thickness of the lithium source is not particularly limited, but is preferably adjusted according to the composition and thickness of the negative electrode. By using a lithium source whose surface layer 10 has a thickness in the above range, non-uniformity at the contact interface between the electrode and the lithium source is improved. In particular, in the case of a thin surface layer of 0.5 μm or less, the surface layer is pierced by irregularities on the surface of the negative electrode, so that the ratio of contact between the lithium metal portion below the surface layer and the negative electrode is particularly preferable. Since the surface layer of the lithium source is an impurity layer formed by reaction of lithium metal, it is originally preferred that the surface layer is extremely thin. However, since the surface layer of the lithium source needs to be uniform on the surface of the lithium source, it is at least 0.03 μm or more. It is preferable that it is the thickness of this.
　さらに好ましい実施形態において、窒化リチウムを主として含む表面層１０は、窒化リチウムを４０質量％以上、より好ましくは５０質量％以上含有する。窒化リチウムは炭酸リチウムなどと比較して高いイオン伝導率（約６ｍＳ／ｃｍ）を有していることから、表面層中に占める割合を多くすることで表面層の導電率が改善される。また、窒化リチウムの状態で電極中に取り込まれた場合にも、電極の導電性を劣化させる可能性が低い。特にリチウムプレドープ量が少量となる場合などは、表面層内の窒化リチウムの割合が、７０質量％以上であることが好ましい。 In a further preferred embodiment, the surface layer 10 mainly containing lithium nitride contains lithium nitride in an amount of 40% by mass or more, more preferably 50% by mass or more. Since lithium nitride has a higher ionic conductivity (about 6 mS / cm) than lithium carbonate or the like, the electrical conductivity of the surface layer is improved by increasing the proportion of the surface in the surface layer. Moreover, even when it is taken into the electrode in the state of lithium nitride, the possibility of deteriorating the conductivity of the electrode is low. In particular, when the amount of lithium pre-doping is small, the proportion of lithium nitride in the surface layer is preferably 70% by mass or more.
　尚、窒化リチウムを主として含む表面層内には、酸化リチウムや炭酸リチウムなど、イオン伝導率が窒化リチウムよりも低い物質は極力含まないことが好ましい。これらのイオン電導率が低い物質の含有率は、２０質量％以下が好ましく、より好ましくは１０質量％以下である。さらに好ましくは１質量％以下である。 In the surface layer mainly containing lithium nitride, it is preferable that a substance having an ionic conductivity lower than that of lithium nitride, such as lithium oxide and lithium carbonate, is not included as much as possible. The content of these substances having low ionic conductivity is preferably 20% by mass or less, and more preferably 10% by mass or less. More preferably, it is 1 mass% or less.
　リチウム源の表面に、窒化リチウムを主として含有する表面層を形成する方法としては、特に限定されない。例えば、特許文献７、特許文献８に記載されているように、リチウム金属をＮ２ガスと接触させて反応させる方法が一般的である。反応温度は、リチウムの融点（１８０．５℃）未満が好ましく、室温（２０℃）程度～１２０℃程度が好ましい。 A method for forming a surface layer mainly containing lithium nitride on the surface of the lithium source is not particularly limited. For example, as described in Patent Document 7 and Patent Document 8, a method is generally used in which lithium metal is reacted with N 2 gas and reacted. The reaction temperature is preferably less than the melting point of lithium (180.5 ° C.), preferably about room temperature (20 ° C.) to about 120 ° C.
　他に、例えば特許文献９の段落００２５に記載されているように、例えば窒素を含む雰囲気下（例えば窒素とアルゴンの混合物）で、５０～３００ｅＶのイオンエネルギーを有するイオンビームをリチウム金属表面に操作しながら同時にリチウム金属を熱蒸着して、リチウム金属表面に窒化リチウムを主として含有する表面層を形成することができる。 In addition, as described in paragraph 0025 of Patent Document 9, for example, an ion beam having an ion energy of 50 to 300 eV is operated on a lithium metal surface in an atmosphere containing nitrogen (for example, a mixture of nitrogen and argon). At the same time, lithium metal can be thermally deposited to form a surface layer mainly containing lithium nitride on the lithium metal surface.
　表面層を形成されるリチウム源の表面には、不純物層などが極力存在しないことが好ましく、圧延や蒸着などによりリチウム源を形成するのと連続して表面層を形成することが好ましい。また、既に表面に不純物層が存在するリチウム源については、物理的あるいは化学的手法により不純物層を除去したのち、Ｎ２ガスと接触させて表面層を形成することができる。 On the surface of the lithium source formed a surface layer, it is preferable that such impurity layer is not as much as possible there, it is preferable to form a surface layer continuously with forming the lithium source due rolling or deposition. For a lithium source having an impurity layer already present on the surface, the surface layer can be formed by removing the impurity layer by a physical or chemical method and then contacting with N 2 gas.
　窒化リチウムを主として含む表面層を有するリチウム源と負極とを接触させるにあたっては、負極とリチウム源が密着していればよく、その方法としては特に限定されない。例えば、（１）負極とリチウム源を重ねた後、加圧により負極とリチウム源を密着させる方法、（２）負極とリチウム源を重ねた後、減圧により電極とリチウム源の界面の隙間を除去する方法などが挙げられる。 In contacting the negative electrode with the lithium source having a surface layer mainly containing lithium nitride, the negative electrode and the lithium source may be in close contact with each other, and the method is not particularly limited. For example, (1) A method in which a negative electrode and a lithium source are stacked and then the negative electrode and the lithium source are brought into close contact with each other by pressurization. (2) A gap between the electrode and the lithium source is removed by depressurization after the negative electrode and the lithium source are stacked. The method of doing is mentioned.
　重ね合わせた負極とリチウム源を加圧する方法では、比較的軟質であるリチウムが電極以外にはみ出さない範囲の圧力を加える必要があり、具体的には、０．５ｋｇｆ／ｃｍ２から３０ｋｇｆ／ｃｍ２の加圧が好ましい。特にリチウム源の厚さが１００μｍ以下である場合は、１５ｋｇｆ／ｃｍ２以下の加圧が好ましい。また、電極面内で均一のリチウムプレドープを行うために、電極面内に対して均一に加圧することが好ましい。 In the method of pressurizing the superimposed negative electrode and lithium source, it is necessary to apply a pressure within a range in which relatively soft lithium does not protrude beyond the electrode. Specifically, 0.5 kgf / cm 2 to 30 kgf / cm A pressure of 2 is preferred. In particular, when the thickness of the lithium source is 100 μm or less, pressurization of 15 kgf / cm 2 or less is preferable. Further, in order to perform uniform lithium pre-doping in the electrode surface, it is preferable to apply pressure uniformly to the electrode surface.
　重ね合わせた負極とリチウム源を減圧により接触させる方法では、接触を維持できる状態で電極とリチウム源を、例えば袋等の変形可能な減圧容器内に配置し、外側から受ける大気圧による減圧容器の変形により、電極とリチウム源とを互いに押し付けながら、その界面に余分な隙間がなくなる範囲で減圧する。また、電極とリチウムをラミネート等の封止可能な袋に入れて減圧を行い、減圧下で封止してもよい。減圧する圧力は、例えば、負極とリチウム箔とを接触させる場合、－０．０５ＭＰａから－０．１ＭＰａの減圧で密着させることが好ましい。 In the method in which the superimposed negative electrode and the lithium source are brought into contact with each other under reduced pressure, the electrode and the lithium source are arranged in a deformable decompression container such as a bag in a state where the contact can be maintained, and the decompression container of the atmospheric pressure received from the outside is received. While the electrode and the lithium source are pressed against each other due to the deformation, the pressure is reduced within a range where there is no excess gap at the interface. Alternatively, the electrode and lithium may be put in a sealable bag such as a laminate to reduce pressure, and sealed under reduced pressure. For example, when the negative electrode and the lithium foil are brought into contact with each other, it is preferable that the pressure be reduced under a reduced pressure of −0.05 MPa to −0.1 MPa.
　更に、（１）と（２）の方法を組み合わせて行ってもよく、また、負極とリチウム源の接触が良好であれば、加圧や減圧を行わなくてもよい。リチウム源から負極への拡散（ドープ）は、リチウムと電極が接触している部分で進行するため、リチウム負極とリチウム源が十分に接触して余分な隙間のない状態ではリチウムと電極の接触面積が大きく、リチウムプレドープが均一に進行しやすい。 Furthermore, the methods (1) and (2) may be combined, and if the contact between the negative electrode and the lithium source is good, it is not necessary to pressurize or depressurize. Since diffusion (doping) from the lithium source to the negative electrode proceeds at the part where the lithium and the electrode are in contact, the contact area between the lithium and the electrode when the lithium negative electrode and the lithium source are in sufficient contact and there is no excess gap The lithium pre-doping tends to proceed uniformly.
　負極とリチウム源とを加熱する温度は、リチウムの拡散が安定して進行し、かつ金属リチウムの融点（１８０．５℃）を超えない温度範囲である必要があり、例えば室温（２０℃）から１８０℃の範囲が好ましい。金属リチウムの融点を超えた温度では、溶融したリチウムが電極以外にはみ出してしまい、効率的にドープすることができない。また、上述した負極とリチウム源を接触させる方法などにより良好な接触が得られている場合にはドープが進行しやすく、室温（２０℃）から１３０℃がより好ましい。特に負極とリチウム源が余分な隙間なく密着している場合には、室温（２０℃）から８０℃が特に好ましい。加熱する時間は、必要とするドープ量および加熱温度にも依存するが、１時間から１００時間の範囲で概ねプレドープが完了でき、好ましくは２時間から１２時間である。 The temperature at which the negative electrode and the lithium source are heated needs to be within a temperature range in which lithium diffusion proceeds stably and does not exceed the melting point of metallic lithium (180.5 ° C.), for example, from room temperature (20 ° C.). A range of 180 ° C. is preferred. At a temperature exceeding the melting point of metallic lithium, the molten lithium protrudes beyond the electrode and cannot be doped efficiently. In addition, when good contact is obtained by the method of bringing the negative electrode and the lithium source into contact with each other, dope is likely to proceed, and room temperature (20 ° C) to 130 ° C is more preferable. In particular, when the negative electrode and the lithium source are in close contact with each other with no extra space, room temperature (20 ° C.) to 80 ° C. is particularly preferable. Although the heating time depends on the required dope amount and the heating temperature, pre-doping can be generally completed within the range of 1 hour to 100 hours, preferably 2 hours to 12 hours.
　また、負極とリチウム源とを接触した状態で加熱する工程で、負極とリチウム源の密着を保持する状態で加圧しつつ加熱してもよい。 Further, in the step of heating in a state where the negative electrode and the lithium source are in contact with each other, the heating may be performed while applying pressure while maintaining the close contact between the negative electrode and the lithium source.
　必要量のリチウムプレドープを完了した後、電極上にリチウムが残存している場合にはこれを取り除いてもよい。基材上に形成したリチウム箔などをリチウム源とした場合には、容易に取り除くことが可能である。 After completing the required amount of lithium pre-doping, if lithium remains on the electrode, it may be removed. When a lithium foil or the like formed on a substrate is used as a lithium source, it can be easily removed.
　なお、前述のように金属リチウムは反応性の高い金属であり、水分とも激しく反応するため、リチウムプレドープに関する作業は低湿度環境で行うことが好ましく、かつリチウム源の劣化を抑制するためにアルゴンなどのリチウムに対して不活性なガス雰囲気で作業を行うことが好ましい。 As described above, metallic lithium is a highly reactive metal and reacts violently with moisture. Therefore, it is preferable to carry out the work related to lithium pre-doping in a low-humidity environment, and to suppress deterioration of the lithium source, argon It is preferable to work in a gas atmosphere inert to lithium.
　［正極］
　本実施形態に係る積層電極体１に備えられている正極２としては、特に限定されず、通常の二次電池用正極を用いることができる。正極２に含まれる正極活物質としては、例えば、ＬｉＭｎＯ２、ＬｉｘＭｎ２Ｏ２（０＜ｘ＜２）等の層状構造を持つマンガン酸リチウムまたはスピネル構造を有するマンガン酸リチウム；ＬｉＣｏＯ２，ＬｉＮｉＯ２またはこれらの遷移金属の一部を他の金属で置き換えたもの；ＬｉＮｉ１／３Ｃｏ１／３Ｍｎ１／３Ｏ２などの特定の遷移金属が半数を超えないリチウム遷移金属酸化物；これらのリチウム遷移金属酸化物において化学量論組成よりもＬｉを過剰にしたもの等が挙げられる。特に、ＬｉαＮｉβＣｏγＡｌδＯ２（１≦α≦１．２、β＋γ＋δ＝１、β≧０．７、γ≦０．２）またはＬｉαＮｉβＣｏγＭｎδＯ２（１≦α≦１．２、β＋γ＋δ＝１、β≧０．６、γ≦０．２）が好ましい。正極に含まれる正極活物質としては、一種を単独で使用してもよく、または二種以上を組み合わせて使用してもよい。 [Positive electrode]
It does not specifically limit as the positive electrode 2 with which the laminated electrode body 1 which concerns on this embodiment is equipped, A normal positive electrode for secondary batteries can be used. Examples of the positive electrode active material contained in the positive electrode 2 include lithium manganate having a layered structure such as LiMnO 2 and Li x Mn 2 O 2 (0 <x <2) or lithium manganate having a spinel structure; LiCoO 2 , LiNiO 2 or a part of these transition metals replaced with other metals; lithium transition metal oxides with less than half of specific transition metals such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 ; Examples of these lithium transition metal oxides include those in which Li is excessive in comparison with the stoichiometric composition. In particular, Li α Ni β Co γ Al δ O 2 (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.7, γ ≦ 0.2) or Li α Ni β Co γ Mn δ O 2 (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.6, γ ≦ 0.2) are preferable. As the positive electrode active material contained in the positive electrode, one kind may be used alone, or two or more kinds may be used in combination.
　正極２の作製方法としては、例えば、少なくとも正極活物質、導電性付与剤、および結着剤を、該結着剤を溶解しうるＮ－メチル－２－ピロリドン等の溶剤中に分散混練して正極スラリーを調整する。導電性付与剤としては、カーボンブラック、グラファイト、アセチレンブラック等の炭素質微粒子が挙げられる。結着剤としては、負極と同様のものを用いることができる。該正極スラリーをアルミニウム等の正極集電体上に塗布し、溶剤を乾燥することで正極を作製することができる。また、乾燥後の正極をプレス加工して、空隙率を調整してもよい。正極集電体としては、負極集電体と同様のものを用いることができる。また、正極集電体上に正極活物質等を蒸着やスパッタ等の気相法により成長することで、正極を製作してもよい。 As a method for producing the positive electrode 2, for example, at least a positive electrode active material, a conductivity imparting agent, and a binder are dispersed and kneaded in a solvent such as N-methyl-2-pyrrolidone that can dissolve the binder. A positive electrode slurry is prepared. The conductive agent, carbon black, graphite, carbonaceous fine particles such as acetylene black. As the binder, the same as the negative electrode can be used. The positive electrode slurry can be prepared by applying the positive electrode slurry onto a positive electrode current collector such as aluminum and drying the solvent. Further, the porosity may be adjusted by pressing the dried positive electrode. As the positive electrode current collector, the same as the negative electrode current collector can be used. Alternatively, the positive electrode may be manufactured by growing a positive electrode active material or the like on the positive electrode current collector by a vapor phase method such as vapor deposition or sputtering.
　［リード端子］
　本実施形態に係る負極リード端子７および正極リード端子７の材質としては、Ａｌ、Ｃｕ、Ｎｉ、Ｔｉ、Ｆｅ、燐青銅、真鍮、ステンレス等が挙げられる。これらは一種を単独で使用してもよく、二種以上を組み合わせて、または合金として用いてもよい。負極リード端子４および正極リード端子５は焼き鈍し処理が施されていてもよい。 [Lead terminal]
Examples of the material of the negative electrode lead terminal 7 and the positive electrode lead terminal 7 according to the present embodiment include Al, Cu, Ni, Ti, Fe, phosphor bronze, brass, and stainless steel. These may be used alone or in combination of two or more or as an alloy. The negative electrode lead terminal 4 and the positive electrode lead terminal 5 may be annealed.
　［セパレータ］
　本実施形態に係る積層電極体１に備えられているセパレータ４としては、特に限定されず、通常の二次電池用セパレータを用いることができる。例えば、織布、不織布、多孔質膜等を用いることができる。特に、ポリプロピレン、ポリエチレン、分子骨格が芳香族からなるポリアミド系の多孔膜が、薄膜化かつ大面積化することができる点、また膜強度や膜抵抗の観点から好ましい。なお、セパレータ４の表面は酸化アルミニウム等の酸化物で被覆されてもよい。また、セパレータ４としては、これらを積層したものを用いることもできる。 [Separator]
It does not specifically limit as the separator 4 with which the laminated electrode body 1 which concerns on this embodiment is equipped, A normal secondary battery separator can be used. For example, a woven fabric, a nonwoven fabric, a porous film, etc. can be used. In particular, polypropylene, polyethylene, and a polyamide-based porous film having a molecular skeleton made of aromatic are preferable from the viewpoints of thinning and large area, and film strength and film resistance. The surface of the separator 4 may be coated with an oxide such as aluminum oxide. Moreover, as the separator 4, what laminated | stacked these can also be used.
　［電解液］
　本実施形態で用いる電解液としては、特に限定されず、通常の二次電池用電解液を用いることができる。電解液としては、例えば、非水溶媒に電解質としてリチウム塩を溶解させた非水電解液を用いることができる。 [Electrolyte]
The electrolytic solution used in the present embodiment is not particularly limited, and a normal secondary battery electrolytic solution can be used. As the electrolytic solution, for example, a nonaqueous electrolytic solution in which a lithium salt is dissolved as an electrolyte in a nonaqueous solvent can be used.
　リチウム塩としては、例えば、ＬｉＰＦ６、ＬｉＡｓＦ６、ＬｉＡｌＣｌ４、ＬｉＣｌＯ４、ＬｉＢＦ４、ＬｉＳｂＦ６、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＳＯ３、Ｌｉ（ＣＦ３ＳＯ２）２，ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＮ（ＳＯ２Ｆ）２等が挙げられる。特に、支持塩としてのリチウム塩は、ＬｉＰＦ６、ＬｉＢＦ４が好ましい。これらの支持塩は、一種を単独で使用してもよく、または二種以上を組み合わせて使用してもよい。 Examples of the lithium salt include LiPF 6 , LiAsF 6 , LiAlCl 4 , LiClO 4 , LiBF 4 , LiSbF 6 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 , LiN (CF 3 SO 2) 2, LiN (SO 2 F) 2 and the like. In particular, the lithium salt as the supporting salt is preferably LiPF 6 or LiBF 4 . These supporting salts may be used alone or in combination of two or more.
　非水溶媒としては、例えば、環状カーボネート類、鎖状カーボネート類、脂肪族カルボン酸エステル類、環状エーテル類、鎖状エーテル類、γ－ラクトン類およびこれらの誘導体からなる群から選択される少なくとも一種以上の有機溶媒が挙げられる。環状カーボネート類の具体例としては、プロピレンカーボネート（ＰＣ）、エチレンカーボネート（ＥＣ）、ブチレンカーボネート（ＢＣ）、ビニレンカーボネート（ＶＣ）およびこれらの誘導体が挙げられる。鎖状カーボネート類の具体例としては、ジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、エチルメチルカーボネート（ＭＥＣ）、ジプロピルカーボネート（ＤＰＣ）およびこれらの誘導体が挙げられる。脂肪族カルボン酸エステル類の具体例としては、ギ酸メチル、酢酸メチル、プロピオン酸エチルおよびこれらの誘導体が挙げられる。環状エーテル類の具体例としては、テトラヒドロフラン、２－メチルテトラヒドロフラン等が挙げられる。鎖状エーテル類の具体例としては、１，２－エトキシエタン（ＤＥＥ）、エトキシメトキシエタン（ＥＭＥ）、ジエチルエーテルおよびこれらの誘導体が挙げられる。γ－ラクトン類の具体例としては、γ―ブチロラクトンおよびこの誘導体が挙げられる。さらに、これら以外にも非水溶媒としては、ジメチルスルホキシド、ホルムアミド、アセトアミド、ジメチルホルムアミド、１，３－ジオキソラン等のジオキソラン、ジオキソラン誘導体、アセトニトリル、プロピルニトリル、ニトロメタン、エチルモノグライム、リン酸トリエステル、トリメトキシメタン、スルホラン、メチルスルホラン、１，３－ジメチル－２－イミダゾリジノン、３－メチル－２－オキソゾリジノン、プロピレンカーボネート誘導体、テトラヒドロフラン誘導体、エチルエーテル、１，３－プロパンスルトン、アニソール、Ｎ－メチルピロリドン、フッ素化カルボン酸エステル等が挙げられる。これらの非水溶媒は、一種を単独で使用してもよく、二種以上を組み合わせて使用してもよい。 Examples of the non-aqueous solvent include at least one selected from the group consisting of cyclic carbonates, chain carbonates, aliphatic carboxylic acid esters, cyclic ethers, chain ethers, γ-lactones, and derivatives thereof. The above organic solvents are mentioned. Specific examples of the cyclic carbonates include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), and derivatives thereof. Specific examples of the chain carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (MEC), dipropyl carbonate (DPC), and derivatives thereof. Specific examples of the aliphatic carboxylic acid esters include methyl formate, methyl acetate, ethyl propionate, and derivatives thereof. Specific examples of the cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran and the like. Specific examples of the chain ethers include 1,2-ethoxyethane (DEE), ethoxymethoxyethane (EME), diethyl ether, and derivatives thereof. Specific examples of the .gamma.-lactones, .gamma.-butyrolactone and the derivatives. In addition to these, non-aqueous solvents include dimethyl sulfoxide, formamide, acetamide, dimethylformamide, dioxolane such as 1,3-dioxolane, dioxolane derivatives, acetonitrile, propylnitrile, nitromethane, ethyl monoglyme, phosphate triester, Trimethoxymethane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxozolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ethyl ether, 1,3-propane sultone, anisole, N- Examples thereof include methyl pyrrolidone and fluorinated carboxylic acid esters. These non-aqueous solvents may be used alone or in combination of two or more.
　また、電解液としてイオン液体を用いることもできる。イオン液体としては、例えば４級アンモニウム－イミド塩等が挙げられる。また、電解液としてリン酸エステルを用いることもできる。リン酸エステルとしては、例えばリン酸トリエチル等が挙げられる。 Also, an ionic liquid can be used as the electrolytic solution. Examples of the ionic liquid include quaternary ammonium-imide salts. Moreover, phosphate ester can also be used as electrolyte solution. Examples of the phosphate ester include triethyl phosphate.
　さらに、液状の電解質ではなく、固体状の電解質を用いてもよい。固体状の電解質としては、例えば、前記電解液をポリアクリロニトリルやポリアクリレート等のポリマーに含浸させたゲル電解質や、ＬｉＰＯＮ、Ｌｉ２Ｓ－ＬｉＰｘＯｙ（ｘ＝１～２、ｙ＝２～４）等の固体電解質が挙げられる。 Further, instead of a liquid electrolyte, a solid electrolyte may be used. Examples of the solid electrolyte include a gel electrolyte obtained by impregnating the electrolyte solution with a polymer such as polyacrylonitrile or polyacrylate, LiPON, Li 2 S—LiP x O y (x = 1 to 2, y = 2 to 4) and the like.
　また、本実施形態のおいてはゲル状の電解質を用いてもよい。 In the present embodiment, a gel electrolyte may be used.
　［外装体］
　本実施形態に係る外装体としては、電解液に安定であり、かつ水蒸気に対して十分なバリア性を持ち、さらに電解液を漏らさずに積層電極体１を封止できるものであれば、特に限定されず、ラミネートフィルム等のラミネート外装体や金属缶等を用いることができる。例えば、積層ラミネート型の二次電池の場合、外装体としては、アルミニウム、シリカをコーティングしたポリエチレン等のラミネートフィルムを用いることができる。 [Exterior body]
The exterior body according to the present embodiment, is stable to the electrolytic solution, and has a sufficient barrier property against water vapor, if further electrolyte as it can seal the laminated electrode body 1 without leaking, and in particular Without being limited, a laminate outer body such as a laminate film, a metal can, or the like can be used. For example, in the case of a laminated laminate type secondary battery, a laminate film such as polyethylene coated with aluminum or silica can be used as the outer package.
　次に、本実施形態を実施例により具体的に説明する。下記の実施例は本発明の好ましい形態を例示するものであり、本発明が下記の実施例に限られるわけではない。 Next, this embodiment will be specifically described by way of examples. The following examples illustrate preferred embodiments of the present invention, and the present invention is not limited to the following examples.
　＜実施例１＞
［負極の作製］
　ＳｉＯ（商品名：「ＳＩＯ１９ＰＢ」、（株）高純度化学研究所）と、カーボンブラック（商品名：「＃３０３０Ｂ」、三菱化学（株）製）と、ポリアミック酸（商品名：「Ｕ－ワニスＡ」、宇部興産（株）製）とを、それぞれ７５：５：２０の質量比で計量した。これらと、ｎ－メチルピロリドン（ＮＭＰ）とをホモジナイザーを用いて混合し、スラリーとした。ＮＭＰと固形分との質量比は５７：４３とした。該スラリーを、銅箔上にドクターブレードを用いて塗布した。その後、１２０℃で７分間加熱し、ＮＭＰを乾燥させた。その後、窒素雰囲気下にて電気炉を用いて３５０℃で１時間加熱し、負極を作製した。 <Example 1>
[Production of negative electrode]
SiO (trade name: “SIO19PB”, High-Purity Chemical Research Laboratory), carbon black (trade name: “# 3030B”, manufactured by Mitsubishi Chemical Corporation), and polyamic acid (trade name: “U-Varnish”) A ”and Ube Industries, Ltd.) were weighed at a mass ratio of 75: 5: 20, respectively. These and n-methylpyrrolidone (NMP) were mixed using a homogenizer to form a slurry. The mass ratio of NMP to solid content was 57:43. The slurry was applied onto a copper foil using a doctor blade. Then, it heated at 120 degreeC for 7 minute (s), and dried NMP. Then, it heated at 350 degreeC for 1 hour using the electric furnace in nitrogen atmosphere, and produced the negative electrode.
　［リチウムプレドープ］
　リチウム源として、厚さ２０μｍのリチウム箔を用意した。厚さ約０．１μｍの主に窒化リチウムからなる表面層（窒化リチウム約９０質量％）が、リチウム箔表面の９０％以上をカバーしている。 [Lithium pre-dope]
A lithium foil having a thickness of 20 μm was prepared as a lithium source. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 0.1 μm covers 90% or more of the lithium foil surface.
　リチウム箔を負極上に重ねた状態でアルミニウムラミネート袋に収容して袋内を－０．１ＭＰａまで減圧しつつ封止した。次にアルミニウムラミネート袋を恒温槽内で１００℃２４時間の加熱処理を行った。熱処理を完了した後、アルミニウムラミネート袋が完全に室温（２３℃）以下に戻った後に袋から電極を取り出し、リチウムプレドープを完了した。本実施例で作製した負極では、熱処理後に全てのリチウム源が電極内にドープされていた。 The lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa. Next, the aluminum laminate bag was heat-treated at 100 ° C. for 24 hours in a thermostatic bath. After the heat treatment was completed, the electrode was taken out from the bag after the aluminum laminate bag was completely returned to room temperature (23 ° C.) or lower, and lithium pre-doping was completed. In the negative electrode produced in this example, all lithium sources were doped in the electrode after the heat treatment.
　［正極の作製］
　正極活物質としてのリチウム遷移金属酸化物（ＬｉＮｉ０．８０Ｃｏ０．１５Ａｌ０．１５Ｏ２）と、導電性付与剤としてカーボンブラックと、正極用結着剤としてポリフッ化ビニリデンとを、質量比９０：５：５で計量し、それらをｎ－メチルピロリドンと混合して、正極スラリーを作製した。正極スラリーを厚さ２０μｍのアルミニウム箔に塗布した後に乾燥し、さらにプレス処理を行うことで、正極を作製した。 [Preparation of positive electrode]
Lithium transition metal oxide (LiNi 0.80 Co 0.15 Al 0.15 O 2 ) as a positive electrode active material, carbon black as a conductivity imparting agent, and polyvinylidene fluoride as a positive electrode binder, Weighed 90: 5: 5 and mixed them with n-methylpyrrolidone to make a positive slurry. The positive electrode slurry was applied to an aluminum foil having a thickness of 20 μm, dried, and further subjected to press treatment to produce a positive electrode.
　［電解液の作製］
　ＥＣ／ＰＣ／ＤＭＣ／ＥＭＣ／ＤＥＣ＝２０／２０／２０／２０／２０（体積比）の混合溶媒に、支持塩としてＬｉＰＦ６を１モル／Ｌの濃度で溶解して、カーボネート系非水電解液を作製した。 [Preparation of electrolyte]
LiPF 6 as a supporting salt is dissolved at a concentration of 1 mol / L in a mixed solvent of EC / PC / DMC / EMC / DEC = 20/20/20/20/20 (volume ratio), and carbonate-based nonaqueous electrolysis to prepare a liquid.
　［二次電池の作製］
　作製した負極の４枚と正極の３枚を、セパレータとしてのポリプロピレン多孔質フィルムを挟みつつ交互に重ねた。負極活物質に覆われていない負極集電体の端部および正極活物質に覆われていない正極集電体の端部をそれぞれ溶接した。さらにその溶接部分に、ニッケル製の負極リード端子およびアルミニウム製の正極リード端子をそれぞれ溶接した。さらに、これらの溶接部分に熱可塑性樹脂からなる被覆材を融着して、積層構造を有する平面的な積層電極体を作製した。 [Production of secondary battery]
Four sheets of the prepared negative electrode and three sheets of the positive electrode were alternately stacked while sandwiching a polypropylene porous film as a separator. The end of the negative electrode current collector not covered with the negative electrode active material and the end of the positive electrode current collector not covered with the positive electrode active material were welded. Furthermore, the negative electrode lead terminal made from nickel and the positive electrode lead terminal made from aluminum were each welded to the welding part. Furthermore, a covering material made of a thermoplastic resin was fused to these welded portions to produce a planar laminated electrode body having a laminated structure.
　作製した積層電極素子を外装体としてのアルミニウムラミネートフィルムで包み、内部に電解液を注液した後、０．１気圧まで減圧した状態で封止した。以上により、二次電池を作製した。 The produced laminated electrode element was wrapped with an aluminum laminate film as an outer package, and an electrolytic solution was injected therein, and then sealed in a state where the pressure was reduced to 0.1 atm. Thus, a secondary battery was produced.
　［リチウムプレドープ量評価］
　リチウムプレドープを行う前後で負極の重量を測定して、塗布面の単位面積あたりの重量の増加分をリチウムプレドープ量として算出した。評価結果を表１に示す。 [Evaluation of lithium pre-doping]
The weight of the negative electrode was measured before and after the lithium pre-doping, and the increase in the weight per unit area of the coated surface was calculated as the lithium pre-doping amount. The evaluation results are shown in Table 1.
　［二次電池特性評価］
　作製した二次電池について、環境温度２０℃、上限電圧４．２Ｖ、下限電圧２．７Ｖ、１Ｃレートで充放電試験を行い、１００サイクル後の放電容量維持率を測定した。１Ｃの設定値は、充放電試験前に充放電を２ｍＡで３回実施したときの、３回目の放電容量を１Ｃとした。評価結果を表１に示す。 [Characteristic evaluation of secondary battery]
The produced secondary battery was subjected to a charge / discharge test at an environmental temperature of 20 ° C., an upper limit voltage of 4.2 V, a lower limit voltage of 2.7 V, and a 1 C rate, and a discharge capacity retention rate after 100 cycles was measured. The set value of 1C was set to 1C for the third discharge capacity when charge / discharge was performed three times at 2 mA before the charge / discharge test. The evaluation results are shown in Table 1.
　＜実施例２＞
［負極の作製］
　実施例１と同様の手法で、負極を作製した。 <Example 2>
[Preparation of negative electrode]
A negative electrode was produced in the same manner as in Example 1.
　［リチウムプレドープ］
　リチウム源として、厚さ２０μｍのリチウム箔を用意した。厚さ約１μｍの主に窒化リチウムから成る表面層（窒化リチウム約９０質量％）が、リチウム箔表面の９０％以上をカバーしている。 [Lithium pre-dope]
A lithium foil having a thickness of 20 μm was prepared as a lithium source. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 μm covers 90% or more of the lithium foil surface.
　リチウム箔を負極上に重ねた状態でアルミニウムラミネート袋に収容して袋内を－０．１ＭＰａまで減圧しつつ封止した。次にアルミニウムラミネート袋を恒温槽内で１００℃２４時間の加熱処理を行った。熱処理を完了した後、アルミニウムラミネート袋が完全に室温（２３℃）以下に戻った後に袋から電極を取り出し、リチウムプレドープを完了した。本実施例で作製した負極では、熱処理後に全てのリチウム源が電極内にドープされていた。 The lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa. Next, the aluminum laminate bag was heat-treated at 100 ° C. for 24 hours in a thermostatic bath. After the heat treatment was completed, the electrode was taken out from the bag after the aluminum laminate bag was completely returned to room temperature (23 ° C.) or lower, and lithium pre-doping was completed. In the negative electrode produced in this example, all lithium sources were doped in the electrode after the heat treatment.
　［正極の作製］
　実施例１と同様の手法で、正極を作製した。 [Preparation of positive electrode]
A positive electrode was produced in the same manner as in Example 1.
　［電解液の作製］
　実施例１と同様の手法で、電解液を作製した。 [Preparation of electrolyte]
An electrolytic solution was prepared in the same manner as in Example 1.
　［二次電池の作製］
　実施例１と同様の手法で、二次電池を作製した。 [Production of secondary battery]
A secondary battery was fabricated in the same manner as in Example 1.
　作製した負極と二次電池を実施例１と同様の手法で評価した。評価結果を表１に示す。 The fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
　＜実施例３＞
［負極の作製］
　実施例１と同様の手法で、負極を作製した。 <Example 3>
[Preparation of negative electrode]
A negative electrode was produced in the same manner as in Example 1.
　［リチウムプレドープ］
　リチウム源として、１５μｍの銅箔（基材）上に形成された厚さ２０μｍのリチウム箔を用意した。厚さ約１μｍの主に窒化リチウムから成る表面層（窒化リチウム約９０質量％）が、リチウム箔表面の９０％以上をカバーしている。 [Lithium pre-dope]
As a lithium source, a 20 μm thick lithium foil formed on a 15 μm copper foil (base material) was prepared. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 μm covers 90% or more of the lithium foil surface.
　リチウム箔を負極上に重ねた状態でアルミニウムラミネート袋に収容して袋内を－０．１ＭＰａまで減圧しつつ封止した。次にアルミニウムラミネート袋を恒温槽内で１００℃２４時間の加熱処理を行った。熱処理を完了した後、アルミニウムラミネート袋が完全に室温（２３℃）以下に戻った後に袋から電極を取り出しリチウム源の基材である銅箔を取り外して、リチウムプレドープを完了した。本実施例で作製した負極では、熱処理後に全てのリチウム源が電極内にドープされていた。 The lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa. It was then subjected to heat treatment 100 ° C. 24 hours aluminum laminated bag in a thermostat. After the heat treatment was completed, after the aluminum laminate bag was completely returned to room temperature (23 ° C.) or lower, the electrode was taken out from the bag and the copper foil as the base material of the lithium source was removed to complete the lithium pre-doping. In the negative electrode produced in this example, all lithium sources were doped in the electrode after the heat treatment.
　［正極の作製］
　実施例１と同様の手法で、正極を作製した。 [Preparation of positive electrode]
A positive electrode was produced in the same manner as in Example 1.
　［電解液の作製］
　実施例１と同様の手法で、電解液を作製した。 [Preparation of electrolyte]
An electrolytic solution was prepared in the same manner as in Example 1.
　［二次電池の作製］
　実施例１と同様の手法で、二次電池を作製した。 [Production of secondary battery]
A secondary battery was fabricated in the same manner as in Example 1.
　作製した負極と二次電池を実施例１と同様の手法で評価した。評価結果を表１に示す。 The fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
　＜実施例４＞
［負極の作製］
　実施例１と同様の手法で、負極を作製した。 <Example 4>
[Preparation of negative electrode]
A negative electrode was produced in the same manner as in Example 1.
　［リチウムプレドープ］
　リチウム源としては、１５μｍの銅箔（基材）上に形成された厚さ５０μｍのリチウム箔を用意した。厚さ約１μｍの主に窒化リチウムから成る表面層（窒化リチウム約９０質量％）であり、リチウム箔表面の９０％以上をカバーしている。 [Lithium pre-dope]
As a lithium source, a 50 μm thick lithium foil formed on a 15 μm copper foil (base material) was prepared. It is a surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 μm and covers 90% or more of the lithium foil surface.
　リチウム箔を負極上に重ねた状態でアルミニウムラミネート袋に収容して袋内を－０．１ＭＰａまで減圧しつつ封止した。次にアルミニウムラミネート袋を恒温槽内で１００℃２４時間の加熱処理を行った。熱処理を完了した後、アルミニウムラミネート袋が完全に室温（２３℃）以下に戻った後に袋から電極を取り出し、リチウム源の基材である銅箔と銅箔上に残留したリチウムを取り外して、リチウムプレドープを完了した。本実施例で作製した負極では、ドープ量に対して余剰なリチウムは基材の銅箔上に残留した。 The lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa. Next, the aluminum laminate bag was heat-treated at 100 ° C. for 24 hours in a thermostatic bath. After the heat treatment is completed, after the aluminum laminate bag is completely returned to room temperature (23 ° C.) or lower, the electrode is taken out of the bag, and the copper foil that is the base material of the lithium source and the lithium remaining on the copper foil are removed. Completed pre-doping. In the negative electrode produced in this example, surplus lithium with respect to the doping amount remained on the copper foil of the base material.
　［正極の作製］
　実施例１と同様の手法で、正極を作製した。 [Preparation of positive electrode]
A positive electrode was produced in the same manner as in Example 1.
　［電解液の作製］
　実施例１と同様の手法で、電解液を作製した。 [Preparation of electrolyte]
An electrolytic solution was prepared in the same manner as in Example 1.
　［二次電池の作製］
　実施例１と同様の手法で、二次電池を作製した。 [Production of secondary battery]
A secondary battery was fabricated in the same manner as in Example 1.
　作製した負極と二次電池を実施例１と同様の手法で評価した。評価結果を表１に示す。 The fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
　＜実施例５＞
［負極の作製］
　実施例１と同様の手法で、負極を作製した。 <Example 5>
[Production of negative electrode]
A negative electrode was produced in the same manner as in Example 1.
　［リチウムプレドープ］
　リチウム源として、１５μｍの銅箔（基材）上に形成された厚さ５０μｍのリチウム箔を用意した。厚さ約１μｍの主に窒化リチウムから成る表面層（窒化リチウム約９０質量％）が、リチウム箔表面の９０％以上をカバーしている。 [Lithium pre-doping]
As a lithium source, a 50 μm thick lithium foil formed on a 15 μm copper foil (base material) was prepared. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 μm covers 90% or more of the lithium foil surface.
　リチウム箔を負極上に重ねた状態で、リチウム源および負極の全面を均一に５ｋｇｆ／ｃｍ２で加圧した。加圧により密着したリチウム源および負極をアルミニウムラミネート袋に収容して減圧封止した。次にアルミニウムラミネート袋を恒温槽内で１００℃２４時間の加熱処理を行った。熱処理を完了した後、アルミニウムラミネート袋が完全に室温（２３℃）以下に戻った後に袋から電極を取り出し、リチウム源の基材である銅箔と銅箔上に残留したリチウムを取り外して、リチウムプレドープを完了した。本実施例で作製した負極では、ドープ量に対して余剰なリチウムは基材の銅箔上に残留した。 With the lithium foil overlaid on the negative electrode, the entire surface of the lithium source and the negative electrode was uniformly pressurized at 5 kgf / cm 2 . The lithium source and the negative electrode that were brought into close contact by pressurization were accommodated in an aluminum laminate bag and sealed under reduced pressure. Next, the aluminum laminate bag was heat-treated at 100 ° C. for 24 hours in a thermostatic bath. After the heat treatment is completed, after the aluminum laminate bag is completely returned to room temperature (23 ° C.) or lower, the electrode is taken out of the bag, and the copper foil that is the base material of the lithium source and the lithium remaining on the copper foil are removed. Completed pre-doping. In the negative electrode produced in this example, surplus lithium with respect to the doping amount remained on the copper foil of the base material.
　［正極の作製］
　実施例１と同様の手法で、正極を作製した。 [Production of positive electrode]
A positive electrode was produced in the same manner as in Example 1.
　［電解液の作製］
　実施例１と同様の手法で、電解液を作製した。 [Preparation of electrolyte]
An electrolytic solution was prepared in the same manner as in Example 1.
　［二次電池の作製］
　実施例１と同様の手法で、二次電池を作製した。 [Production of secondary battery]
A secondary battery was fabricated in the same manner as in Example 1.
　作製した負極と二次電池を実施例１と同様の手法で評価した。評価結果を表１に示す。 The fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
　＜実施例６＞
［負極の作製］
　実施例１と同様の手法で、負極を作製した。 <Example 6>
[Preparation of negative electrode]
A negative electrode was produced in the same manner as in Example 1.
　［リチウムプレドープ］
　リチウム源として、１５μｍの銅箔（基材）上に形成された厚さ５０μｍのリチウム箔を用意した。厚さ約１μｍの主に窒化リチウムから成る表面層（窒化リチウム約９０質量％）が、リチウム箔表面の９０％以上をカバーしている。 [Lithium pre-dope]
As a lithium source, a 50 μm thick lithium foil formed on a 15 μm copper foil (base material) was prepared. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 μm covers 90% or more of the lithium foil surface.
　リチウム箔を負極上に重ねた状態で、リチウム源および負極の全面を均一に１０ｋｇｆ／ｃｍ２で加圧した。加圧により密着したリチウム源および負極をアルミニウムラミネート袋に収容して減圧封止した。次にアルミニウムラミネート袋を恒温槽内で１００℃１６時間の加熱処理を行った。熱処理を完了した後、アルミニウムラミネート袋が完全に室温（２３℃）以下に戻った後に袋から電極を取り出し、リチウム源の基材である銅箔と銅箔上に残留したリチウムを取り外して、リチウムプレドープを完了した。本実施例で作製した負極では、ドープ量に対して余剰なリチウムは基材の銅箔上に残留した。 With the lithium foil overlaid on the negative electrode, the entire surface of the lithium source and the negative electrode was uniformly pressurized at 10 kgf / cm 2 . The lithium source and the negative electrode that were brought into close contact by pressurization were accommodated in an aluminum laminate bag and sealed under reduced pressure. Next, the aluminum laminate bag was heat-treated at 100 ° C. for 16 hours in a thermostatic bath. After the heat treatment is completed, after the aluminum laminate bag is completely returned to room temperature (23 ° C.) or lower, the electrode is taken out of the bag, and the copper foil that is the base material of the lithium source and the lithium remaining on the copper foil are removed. Completed pre-doping. In the negative electrode produced in this example, surplus lithium with respect to the doping amount remained on the copper foil of the base material.
　［正極の作製］
　実施例１と同様の手法で、正極を作製した。 [Production of positive electrode]
A positive electrode was produced in the same manner as in Example 1.
　［電解液の作製］
　実施例１と同様の手法で、電解液を作製した。 [Preparation of electrolyte]
An electrolytic solution was prepared in the same manner as in Example 1.
　［二次電池の作製］
　実施例１と同様の手法で、二次電池を作製した。 [Production of secondary battery]
A secondary battery was fabricated in the same manner as in Example 1.
　作製した負極と二次電池を実施例１と同様の手法で評価した。評価結果を表１に示す。 The fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
　＜実施例７＞
［負極の作製］
　実施例１と同様の手法で、負極を作製した。 <Example 7>
[Preparation of negative electrode]
A negative electrode was produced in the same manner as in Example 1.
　［リチウムプレドープ］
　リチウム源として、１５μｍの銅箔（基材）上に形成された厚さ５０μｍのリチウム箔を用意した。厚さ約１μｍの主に窒化リチウムから成る表面層（窒化リチウム約９０質量％）が、リチウム箔表面の９０％以上をカバーしている。 [Lithium pre-dope]
As a lithium source, a 50 μm thick lithium foil formed on a 15 μm copper foil (base material) was prepared. A surface layer (about 90% by mass of lithium nitride) mainly made of lithium nitride having a thickness of about 1 μm covers 90% or more of the lithium foil surface.
　リチウム箔を負極上に重ねた状態で、リチウム源および負極の全面を均一に５ｋｇｆ／ｃｍ２で加圧した。加圧により密着したリチウム源および負極をアルミニウムラミネート袋に収容して減圧封止した。次にアルミニウムラミネート袋を恒温槽内で６０℃２４時間の加熱処理を行った。熱処理を完了した後、アルミニウムラミネート袋が完全に室温（２３℃）以下に戻った後に袋から電極を取り出し、リチウム源の基材である銅箔と銅箔上に残留したリチウムを取り外して、リチウムプレドープを完了した。本実施例で作製した負極では、ドープ量に対して余剰なリチウムは基材の銅箔上に残留した。 With the lithium foil overlaid on the negative electrode, the entire surface of the lithium source and the negative electrode was uniformly pressurized at 5 kgf / cm 2 . The lithium source and the negative electrode that were brought into close contact by pressurization were accommodated in an aluminum laminate bag and sealed under reduced pressure. Next, the aluminum laminate bag was heat-treated at 60 ° C. for 24 hours in a thermostatic bath. After the heat treatment is completed, after the aluminum laminate bag is completely returned to room temperature (23 ° C.) or lower, the electrode is taken out of the bag, and the copper foil that is the base material of the lithium source and the lithium remaining on the copper foil are removed. Completed pre-doping. In the negative electrode produced in this example, surplus lithium with respect to the doping amount remained on the copper foil of the base material.
　［正極の作製］
　実施例１と同様の手法で、正極を作製した。 [Production of positive electrode]
A positive electrode was produced in the same manner as in Example 1.
　［電解液の作製］
　実施例１と同様の手法で、電解液を作製した。 [Preparation of electrolyte]
An electrolytic solution was prepared in the same manner as in Example 1.
　［二次電池の作製］
　実施例１と同様の手法で、二次電池を作製した。 [Production of secondary battery]
A secondary battery was fabricated in the same manner as in Example 1.
　作製した負極と二次電池を実施例１と同様の手法で評価した。評価結果を表１に示す。 The fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
　＜参考例＞
　リチウムプレドープを実施しなかったことを除いて、実施例１と同様にして、二次電池を作製して評価した。評価結果を表１に示す。 <Reference example>
A secondary battery was fabricated and evaluated in the same manner as in Example 1 except that lithium pre-doping was not performed. The evaluation results are shown in Table 1.
　＜比較例１＞
［負極の作製］
　実施例１と同様の手法で、負極を作製した。 <Comparative Example 1>
[Production of negative electrode]
A negative electrode was produced in the same manner as in Example 1.
　［リチウムプレドープ］
　リチウム源として、厚さ２０μｍのリチウム箔を用意した。リチウム箔の表面には、主に炭酸リチウムと窒化リチウムから成る厚さ約２μｍの表面層が形成されており、表面層中、窒化リチウムの割合は２５質量％、炭酸リチウムの割合は約７０質量％、酸化リチウムの割合が約５％であった。表面層はリチウム箔表面の９０％以上をカバーしている。 [Lithium pre-dope]
A lithium foil having a thickness of 20 μm was prepared as a lithium source. On the surface of the lithium foil, which is mainly the surface layer having a thickness of about 2μm consisting of lithium carbonate and lithium nitride is formed, in the surface layer, the proportion of lithium nitride is 25% by weight, the proportion of lithium carbonate is from about 70 weight %, And the proportion of lithium oxide was about 5%. The surface layer covers 90% or more of the lithium foil surface.
　リチウム箔を負極上に重ねた状態でアルミニウムラミネート袋に収容して袋内を－０．１ＭＰａまで減圧しつつ封止した。次にアルミニウムラミネート袋を恒温槽内で１００℃２４時間の加熱処理を行った。熱処理を完了した後、アルミラミネート袋が完全に室温（２３℃）以下に戻った後に袋から電極を取り出し、リチウムプレドープを完了した。本実施例で作製した負極では、熱処理後に電極上に残ったリチウム源を除去した。 The lithium foil was placed on the negative electrode in an aluminum laminate bag and sealed while reducing the pressure to -0.1 MPa. It was then subjected to heat treatment 100 ° C. 24 hours aluminum laminated bag in a thermostat. After the heat treatment was completed, the electrode was taken out from the bag after the aluminum laminate bag was completely returned to room temperature (23 ° C.) or lower, and lithium pre-doping was completed. In the negative electrode produced in this example, to remove the lithium source left on the electrode after the heat treatment.
　［正極の作製］
　実施例１と同様の手法で、正極を作製した。 [Production of positive electrode]
A positive electrode was produced in the same manner as in Example 1.
　［電解液の作製］
　実施例１と同様の手法で、電解液を作製した。 Preparation of electrolyte solution]
An electrolytic solution was prepared in the same manner as in Example 1.
　［二次電池の作製］
　実施例１と同様の手法で、二次電池を作製した。 [Production of secondary battery]
A secondary battery was fabricated in the same manner as in Example 1.
　作製した負極と二次電池を実施例１と同様の手法で評価した。評価結果を表１に示す。 The fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　二次電池作製前にリチウムプレドープを行うことで、良好な容量維持率を有する二次電池を作製することができた（実施例１～７）。特に、主に窒化リチウムからなる表面層を有するリチウム源を用いることが、リチウムドープ量の安定に有効であり、その結果、良好な容量維持率が得られることを確認した。同じ手法によるリチウムプレドープを行っても、リチウム源が不均一な表面層を有する場合には、適量のリチウムプレドープ量が得られず、さらに容量維持率への効果が十分に得られていない（実施例１、２、比較例１）。また、基材上に形成したリチウム源を用いてプレドープをおこなっても、同様の効果が得られることを確認した（実施例３）。また、リチウム源の厚さを変えて、リチウムプレドープ後に残ったリチウム源を除去した場合も、同様の効果が得られることを確認した（実施例４）。さらに、リチウム源と電極とを加圧を用いて密着させた場合も、同様の効果が得られることを確認した（実施例５，６）。また、リチウムプレドープ工程において、加熱する温度と時間を変えても同様の効果が得られることを確認した（実施例５～７）。 By performing lithium pre-doping before producing the secondary battery, it was possible to produce secondary batteries having a good capacity retention rate (Examples 1 to 7). In particular, it was confirmed that the use of a lithium source having a surface layer mainly composed of lithium nitride is effective in stabilizing the lithium doping amount, and as a result, a good capacity retention rate was obtained. Even if lithium pre-doping is performed by the same method, if the lithium source has a non-uniform surface layer, an appropriate amount of lithium pre-doping cannot be obtained, and the effect on the capacity retention rate is not sufficiently obtained. (Examples 1 and 2 and Comparative Example 1). Further, it was confirmed that the same effect was obtained even when pre-doping was performed using a lithium source formed on a substrate (Example 3). Further, it was confirmed that the same effect was obtained when the thickness of the lithium source was changed and the lithium source remaining after the lithium pre-doping was removed (Example 4). Furthermore, it was confirmed that the same effect was obtained when the lithium source and the electrode were brought into close contact with each other using pressure (Examples 5 and 6). Further, it was confirmed that the same effect can be obtained even if the heating temperature and time are changed in the lithium pre-doping step (Examples 5 to 7).
　＜実施例８＞
［負極の作製］
　ＳｉＯ（商品名：「ＳＩＯ１９ＰＢ」、（株）高純度化学研究所）表面に化学気相成長法により炭素を均一に被覆（被覆量はＳｉＯに対し質量比で約５／７５）したのち、炭素被覆ＳｉＯとポリアミック酸（商品名：「Ｕ－ワニスＡ」、宇部興産（株）製）とを、それぞれ８０：２０の質量比で計量した。これらと、ｎ－メチルピロリドン（ＮＭＰ）とをホモジナイザーを用いて混合し、スラリーとした。ＮＭＰと固形分との質量比は５７：４３とした。該スラリーを、銅箔上にドクターブレードを用いて塗布した。その後、１２０℃で７分間加熱し、ＮＭＰを乾燥させた。その後、窒素雰囲気下にて電気炉を用いて３５０℃で１時間加熱し、負極を作製した。 <Example 8>
[Preparation of negative electrode]
After the surface of SiO (trade name: “SIO19PB”, High-Purity Chemical Laboratory Co., Ltd.) is uniformly coated with carbon by chemical vapor deposition (coating amount is about 5/75 by mass with respect to SiO), carbon The coated SiO and polyamic acid (trade name: “U-Varnish A”, manufactured by Ube Industries, Ltd.) were weighed at a mass ratio of 80:20, respectively. These and n-methylpyrrolidone (NMP) were mixed using a homogenizer to form a slurry. The mass ratio of NMP to solid content was 57:43. The slurry was applied onto a copper foil using a doctor blade. Then, it heated at 120 degreeC for 7 minute (s), and dried NMP. Then, it heated at 350 degreeC for 1 hour using the electric furnace in nitrogen atmosphere, and produced the negative electrode.
　［リチウムプレドープ］
　実施例１と同様の方法で、リチウムプレドープを実施した。リチウムプレドープ量は１．１ｍｇ／ｃｍ２であった。 [Lithium pre-doping]
Lithium pre-doping was performed in the same manner as in Example 1. The amount of lithium pre-doping was 1.1 mg / cm 2 .
　［正極の作製］
　実施例１と同様の手法で、正極を作製した。 [Production of positive electrode]
A positive electrode was produced in the same manner as in Example 1.
　［電解液の作製］
　実施例１と同様の手法で、電解液を作製した。 [Preparation of electrolyte]
An electrolytic solution was prepared in the same manner as in Example 1.
　［二次電池の作製］
　実施例１と同様の手法で、二次電池を作製した。 [Production of secondary battery]
A secondary battery was fabricated in the same manner as in Example 1.
　作製した負極と二次電池を実施例１と同様の手法で評価した。容量維持率は８８％であった。 The fabricated negative electrode and secondary battery were evaluated in the same manner as in Example 1. The capacity retention rate was 88%.
　本発明の二次電池は、高エネルギー密度で、かつサイクル特性が良好な二次電池であり、電源を必要とするあらゆる産業分野、ならびに電気的エネルギーの輸送、貯蔵および供給に関する産業分野にて利用することができる。具体的には、モバイル機器の電源、移動・輸送用媒体の電源、バックアップ電源、太陽光発電、風力発電などで発電した電力を貯める蓄電設備などに、利用することができる。 The secondary battery of the present invention is a secondary battery having high energy density and good cycle characteristics, and is used in all industrial fields that require a power source and industrial fields related to transportation, storage and supply of electrical energy. can do. Specifically, it can be used for a power source of a mobile device, a power source of a moving / transport medium, a backup power source, a solar power generation, a wind power generation, and a power storage facility for storing power generated by the power generation.
１　　積層電極体
２　　正極
３　　負極
４　　セパレータ
５　　正極集電体
６　　負極集電体
７　　正極リード端子
８　　負極リード端子
９　　リチウム金属
１０　　窒化リチウムを主として含む表面層
１１　　表面層
１２　　リチウム源の基材 DESCRIPTION OF SYMBOLS 1 Laminated electrode body 2 Positive electrode 3 Negative electrode 4 Separator 5 Positive electrode collector 6 Negative electrode collector 7 Positive electrode lead terminal 8 Negative electrode lead terminal 9 Lithium metal 10 Surface layer 11 mainly containing lithium nitride 11 Surface layer 12 Base material of lithium source

Claims (11)

  1. 　リチウムを吸蔵、放出が可能な活物質を含む負極と正極が対向に配置された積層電極体を備えるリチウムイオン二次電池の製造方法であって、
    　窒化リチウムを３０％質量以上含む表面層を有するリチウム源を、負極活物質に接触させる工程を有することを特徴とするリチウムイオン二次電池の製造方法。     A method for producing a lithium ion secondary battery comprising a laminated electrode body in which a negative electrode and a positive electrode containing an active material capable of inserting and extracting lithium are arranged opposite to each other,
    A method for producing a lithium ion secondary battery, comprising a step of bringing a lithium source having a surface layer containing 30% by mass or more of lithium nitride into contact with a negative electrode active material.
  2. 　前記リチウム源が、リチウムを８０質量％以上含む金属であることを特徴とする請求項１に記載の二次電池の製造方法。 The method for producing a secondary battery according to claim 1, wherein the lithium source is a metal containing 80 mass% or more of lithium.
  3. 　前記リチウム源を前記負極活物質に接触させる工程が、前記リチウム源を負極中の前記負極活物質と接触させることを含むことを特徴とする請求項１または２に記載のリチウムイオン二次電池の製造方法。 3. The lithium ion secondary battery according to claim 1, wherein the step of bringing the lithium source into contact with the negative electrode active material includes bringing the lithium source into contact with the negative electrode active material in the negative electrode. Production method.
  4. 　前記リチウム源の形態が、箔であることを特徴とする請求項１～３のいずれか１項に記載のリチウムイオン二次電池の製造方法。 The method for producing a lithium ion secondary battery according to any one of claims 1 to 3, wherein the form of the lithium source is a foil.
  5. 　前記リチウム源が、基材上に形成した箔であることを特徴とする請求項４に記載のリチウムイオン二次電池の製造方法。 The method for producing a lithium ion secondary battery according to claim 4, wherein the lithium source is a foil formed on a substrate.
  6. 　前記表面層に含まれる窒化リチウムの割合が、少なくとも５０ｗｔ％以上であることを特徴とする請求項１～５のいずれか１項に記載のリチウムイオン二次電池の製造方法。 The method for producing a lithium ion secondary battery according to any one of claims 1 to 5, wherein a ratio of lithium nitride contained in the surface layer is at least 50 wt% or more.
  7. 　前記表面層の厚さが、少なくとも０．０３μｍ以上であることを特徴とする請求項１～６のいずれか１項に記載のリチウムイオン二次電池の製造方法。 The method of manufacturing a lithium ion secondary battery according to any one of claims 1 to 6, wherein the thickness of the surface layer is at least 0.03 µm or more.
  8. 　前記表面層の厚さが、前記リチウム源の厚さの３０％以下であることを特徴とする請求項１～７のいずれか１項に記載のリチウムイオン二次電池の製造方法。 The method for manufacturing a lithium ion secondary battery according to any one of claims 1 to 7, wherein the thickness of the surface layer is 30% or less of the thickness of the lithium source.
  9. 　前記リチウム源を前記負極活物質に接触させる工程を、前記リチウム源を前記負極に対向配置し、室温から１８０℃の範囲で実施することを特徴とする請求項１～８のいずれか１項に記載のリチウムイオン二次電池の製造方法。 The method according to any one of claims 1 to 8, wherein the step of bringing the lithium source into contact with the negative electrode active material is performed in a range of room temperature to 180 ° C with the lithium source facing the negative electrode. The manufacturing method of the lithium ion secondary battery of description.
  10. 　前記リチウム源を前記負極活物質に接触させる工程が、前記リチウム源を前記負極に対向配置し、圧力０．５ｋｇｆ／ｃｍ２以上３０ｋｇｆ／ｃｍ２以下で加圧することを特徴とする請求項１～９のいずれか１項に記載のリチウムイオン二次電池の製造方法。 The step of bringing the lithium source into contact with the negative electrode active material includes placing the lithium source opposite to the negative electrode and pressurizing at a pressure of 0.5 kgf / cm 2 or more and 30 kgf / cm 2 or less. 10. The method for producing a lithium ion secondary battery according to any one of 9 above.
  11. 　請求項１～１０のいずれか１項に記載の製造方法により製造されたリチウムイオン二次電池。 A lithium ion secondary battery produced by the production method according to any one of claims 1 to 10.
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015185459A (en) * 2014-03-25 2015-10-22 三菱自動車工業株式会社 electrode manufacturing method
JP2015198055A (en) * 2014-04-02 2015-11-09 日本電信電話株式会社 Sodium secondary battery, method of manufacturing negative electrode for sodium secondary battery, and method of manufacturing sodium secondary battery including negative electrode
JP2016110777A (en) * 2014-12-04 2016-06-20 積水化学工業株式会社 Method for manufacturing lithium ion secondary battery
JP2017152139A (en) * 2016-02-23 2017-08-31 積水化学工業株式会社 Lithium ion secondary battery
JP2020518105A (en) * 2017-08-10 2020-06-18 エルジー・ケム・リミテッド Method for producing lithium metal/inorganic composite thin film and method for prelithiation of negative electrode of lithium secondary battery using the same
CN111952517A (en) * 2020-08-26 2020-11-17 复阳固态储能科技(溧阳)有限公司 Diaphragm containing lithium nitride thin film layer and preparation method and application thereof
KR20210093335A (en) * 2018-11-27 2021-07-27 베이징 웨이리온 뉴 에너지 테크놀로지 컴퍼니 리미티드 A system for manufacturing an electrode with high cycle efficiency, a method for manufacturing an electrode with high cycle efficiency, and application thereof
CN114388768A (en) * 2016-01-29 2022-04-22 株式会社半导体能源研究所 Storage battery, battery management unit, and electronic apparatus

Families Citing this family (3)

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Publication number Priority date Publication date Assignee Title
KR102617865B1 (en) 2017-05-12 2023-12-26 주식회사 엘지에너지솔루션 Method for preparing negative electrode for lithium secondary battery
KR102265214B1 (en) 2017-05-19 2021-06-16 (주)엘지에너지솔루션 Pre-lithiation Method of Silicon oxide Anode Electrodes for secondary battery
JP7309032B2 (en) * 2020-02-27 2023-07-14 エルジー エナジー ソリューション リミテッド Method for manufacturing lithium metal negative electrode, lithium metal negative electrode manufactured by the same, and lithium-sulfur battery including the same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003123740A (en) * 2001-10-18 2003-04-25 Nec Corp Negative electrode for secondary battery, and secondary battery using the same
JP2004319489A (en) * 2003-04-17 2004-11-11 Samsung Sdi Co Ltd Negative electrode for lithium battery, its manufacturing method and lithium battery including the negative electrode
JP2011096470A (en) * 2009-10-29 2011-05-12 National Institute Of Advanced Industrial Science & Technology Negative electrode material in all solid lithium ion secondary battery, and manufacturing method of all solid lithium ion secondary battery
JP2011222151A (en) * 2010-04-05 2011-11-04 Shin Etsu Chem Co Ltd Negative electrode material for nonaqueous secondary battery and method for producing the material, and lithium ion secondary battery

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003123740A (en) * 2001-10-18 2003-04-25 Nec Corp Negative electrode for secondary battery, and secondary battery using the same
JP2004319489A (en) * 2003-04-17 2004-11-11 Samsung Sdi Co Ltd Negative electrode for lithium battery, its manufacturing method and lithium battery including the negative electrode
JP2011096470A (en) * 2009-10-29 2011-05-12 National Institute Of Advanced Industrial Science & Technology Negative electrode material in all solid lithium ion secondary battery, and manufacturing method of all solid lithium ion secondary battery
JP2011222151A (en) * 2010-04-05 2011-11-04 Shin Etsu Chem Co Ltd Negative electrode material for nonaqueous secondary battery and method for producing the material, and lithium ion secondary battery

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015185459A (en) * 2014-03-25 2015-10-22 三菱自動車工業株式会社 electrode manufacturing method
JP2015198055A (en) * 2014-04-02 2015-11-09 日本電信電話株式会社 Sodium secondary battery, method of manufacturing negative electrode for sodium secondary battery, and method of manufacturing sodium secondary battery including negative electrode
JP2016110777A (en) * 2014-12-04 2016-06-20 積水化学工業株式会社 Method for manufacturing lithium ion secondary battery
CN114388768A (en) * 2016-01-29 2022-04-22 株式会社半导体能源研究所 Storage battery, battery management unit, and electronic apparatus
JP2017152139A (en) * 2016-02-23 2017-08-31 積水化学工業株式会社 Lithium ion secondary battery
JP7045575B2 (en) 2017-08-10 2022-04-01 エルジー エナジー ソリューション リミテッド A method for producing a lithium metal-inorganic composite thin film and a method for prelithiumizing a negative electrode of a lithium secondary battery using the same.
JP2020518105A (en) * 2017-08-10 2020-06-18 エルジー・ケム・リミテッド Method for producing lithium metal/inorganic composite thin film and method for prelithiation of negative electrode of lithium secondary battery using the same
US11316145B2 (en) 2017-08-10 2022-04-26 Lg Energy Solution, Ltd. Method for forming lithium metal and inorganic material composite thin film and method for pre-lithiation of negative electrode for lithium secondary battery by using same
KR20210093335A (en) * 2018-11-27 2021-07-27 베이징 웨이리온 뉴 에너지 테크놀로지 컴퍼니 리미티드 A system for manufacturing an electrode with high cycle efficiency, a method for manufacturing an electrode with high cycle efficiency, and application thereof
JP2022509237A (en) * 2018-11-27 2022-01-20 北京▲衛▼▲藍▼新能源科技有限公司 A system for manufacturing high cycle efficiency electrodes, a method for manufacturing high cycle efficiency electrodes, and their applications.
JP7158585B2 (en) 2018-11-27 2022-10-21 北京▲衛▼▲藍▼新能源科技有限公司 System for manufacturing electrode with high cycle efficiency, method for manufacturing electrode with high cycle efficiency and its application
KR102656071B1 (en) * 2018-11-27 2024-04-08 베이징 웰리온 뉴 에너지 테크놀로지 컴퍼니 리미티드 System for manufacturing electrodes with high cycle efficiency, method for manufacturing electrodes with high cycle efficiency, and applications thereof
CN111952517A (en) * 2020-08-26 2020-11-17 复阳固态储能科技(溧阳)有限公司 Diaphragm containing lithium nitride thin film layer and preparation method and application thereof

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