WO2018117089A1 - Électrode pour batterie au lithium-ion, et batterie au lithium-ion - Google Patents

Électrode pour batterie au lithium-ion, et batterie au lithium-ion Download PDF

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Publication number
WO2018117089A1
WO2018117089A1 PCT/JP2017/045490 JP2017045490W WO2018117089A1 WO 2018117089 A1 WO2018117089 A1 WO 2018117089A1 JP 2017045490 W JP2017045490 W JP 2017045490W WO 2018117089 A1 WO2018117089 A1 WO 2018117089A1
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active material
electrode active
negative electrode
layer
group
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PCT/JP2017/045490
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English (en)
Japanese (ja)
Inventor
勇輔 中嶋
浩太郎 那須
雄樹 草地
大澤　康彦
佐藤　一
赤間　弘
堀江　英明
Original Assignee
日産自動車株式会社
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Priority claimed from JP2017238951A external-priority patent/JP2018101624A/ja
Application filed by 日産自動車株式会社 filed Critical 日産自動車株式会社
Publication of WO2018117089A1 publication Critical patent/WO2018117089A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to an electrode for a lithium ion battery and a lithium ion battery.
  • an active material having a larger theoretical capacity that is, a material that can occlude more lithium ions per unit volume has attracted attention.
  • the volume change associated with insertion / extraction of lithium ions also increases. For this reason, there is a case where the material self-destructs due to the volume change, and the active material layer is easily peeled off from the current collector surface.
  • Japanese Unexamined Patent Application Publication No. 2016-103337 discloses a lithium ion in which expansion of a negative electrode is suppressed by adjusting a mixing ratio of at least one of silicon and a silicon compound and carbon and a particle diameter thereof to a predetermined range.
  • a battery is disclosed.
  • the negative electrode described in JP-A-2016-103337 uses a binder, if the electrode thickness is too thick, the negative electrode active material is peeled off from the surface of the negative electrode current collector. There was a problem.
  • the binder may restrict the expansion and contraction of silicon and the silicon compound, and may easily break. Furthermore, the effect of suppressing the expansion of the negative electrode is not sufficient, and there is room for further improvement in terms of improving the energy density and cycle characteristics.
  • the present invention has been made in view of the above problems, and an object thereof is to provide a lithium ion battery electrode and a lithium ion battery excellent in energy density and cycle characteristics.
  • one embodiment of the present invention is an electrode for a lithium ion battery that includes an electrode current collector and an electrode active material layer, and the electrode active material layer is an electrode active material composition containing an electrode active material.
  • a pressure relaxation layer made of a conductive carbon filler is disposed between the electrode current collector and the electrode active material layer.
  • the pressure relaxation layer is disposed on the electrode active material layer side of the pressure relaxation layer.
  • the present invention relates to an electrode for a lithium ion battery, wherein the electrode active material is present in the vicinity of the surface; and a lithium ion battery provided with the electrode.
  • FIG. 1 is a cross-sectional view schematically showing an example of an electrode for a lithium ion battery of the present invention.
  • 2 (a) and 2 (b) are cross-sectional views schematically showing the state before and after charge / discharge of the electrode active material layer and the pressure relaxation layer constituting the electrode for a lithium ion battery of the present invention.
  • An electrode for a lithium ion battery is an electrode for a lithium ion battery including an electrode current collector and an electrode active material layer, wherein the electrode active material layer includes an electrode active material.
  • a pressure relaxation layer made of a conductive carbon filler is disposed between the electrode current collector and the electrode active material layer, and the electrode of the pressure relaxation layer is made of a non-binding body of an active material composition.
  • the electrode active material is present in the vicinity of the surface on the active material layer side.
  • FIG. 1 is a cross-sectional view schematically showing an example of an electrode for a lithium ion battery according to the present invention.
  • the electrode 1 for a lithium ion battery includes an electrode current collector 10 and an electrode active material layer 30, and is electrically conductive between the electrode current collector 10 and the electrode active material layer 30.
  • a pressure relaxation layer 20 made of a carbon filler is disposed.
  • the electrode active material layer 30 is a non-binding body of an electrode active material composition containing an electrode active material.
  • a pressure relaxation layer is provided between the electrode current collector and the electrode active material layer.
  • the pressure relaxation layer contracts, whereby the volume change of the entire electrode can be suppressed.
  • the pressure relaxation layer expands, whereby the volume change of the entire electrode can be suppressed. Therefore, peeling of the electrode active material layer accompanying charge / discharge can be suppressed and cycle characteristics can be improved.
  • the electrode active material layer is a non-binding body of an electrode active material composition containing an electrode active material.
  • the non-binding body means that the positions of the electrode active materials constituting the electrode active material layer are not fixed by a binder (also referred to as a binder).
  • An electrode active material layer in a conventional lithium ion battery is manufactured by applying a slurry in which an electrode active material and a binder are dispersed in a solvent to the surface of an electrode current collector, etc., and heating and drying.
  • the electrode active material layer is in a state of being hardened by a binder. At this time, the electrode active materials are fixed to each other by the binder, and the positions of the electrode active materials are fixed.
  • the electrode active material layer is hardened with a binder, excessive stress is applied to the electrode active material due to expansion / contraction at the time of charge / discharge, and the electrode active material layer is easily broken.
  • the electrode active material layer is fixed to the surface of the electrode current collector by the binder, the electrode active material layer solidified by the binder due to expansion / contraction during charge / discharge of the electrode active material is cracked. May occur, or the electrode active material layer may be peeled off from the surface of the electrode current collector.
  • the components in the electrode active material layer are not bound to each other. Also, the position is not fixed. Therefore, self-destruction caused by expansion / contraction during charging / discharging of the electrode active material can be suppressed. Furthermore, since the electrode active material layer constituting the lithium ion battery electrode of the present invention is not fixed to the surface of the electrode current collector by a binder, the electrode active material may be expanded or contracted during charging / discharging. Since the electrode active material layer is not cracked or peeled off, deterioration of cycle characteristics can be suppressed.
  • the lithium ion battery electrode of this embodiment can provide a lithium ion battery excellent in energy density and cycle characteristics.
  • a pressure relaxation layer made of a conductive carbon filler is disposed between the electrode current collector and the electrode active material layer.
  • the electrical resistivity of the conductive carbon filler constituting the pressure relaxation layer is preferably 50 ⁇ ⁇ m or less.
  • the pressure relaxation layer is composed of a conductive filler, the pressure relaxation layer has voids, and when the electrode active material enters the voids, an electrode active material layer side surface of the pressure relaxation layer is disposed near the electrode. Active material is present.
  • the bulk density of the conductive carbon filler constituting the pressure relaxation layer is not particularly limited, but is 0.01 to 0.7 g / cm 3 from the viewpoint of easy expansion and contraction absorption of the electrode active material layer. Is preferred.
  • the bulk density of the conductive carbon filler is measured according to JIS K5101-12-1 Pigment test method-Part 12: Apparent density or apparent specific volume-Section 1: Standing method.
  • the pressure relaxation layer may contain components other than the conductive carbon filler.
  • the conductive carbon filler is preferably included as a main component of solid content (a component of 50 mass% or more as a mass ratio).
  • the mass ratio of the conductive carbon filler to the total mass of 100 mass% of the solid content of the pressure relaxation layer is preferably 50 mass% or more, more preferably 70 mass% or more, and further preferably 80 mass%. More preferably, it is 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass (all solid content is conductive carbon filler).
  • the thickness of the pressure relaxation layer is not particularly limited and can be adjusted according to the thickness of the electrode, but it is preferably 2 to 500 ⁇ m, more preferably 30 to 100 ⁇ m.
  • the thickness of the pressure relaxation layer is within this range, it becomes easy to achieve both absorption of expansion and contraction of the electrode active material layer and improvement of energy density.
  • the electrode active material is present near the surface on the electrode active material layer side of the pressure relaxation layer, but the thickness of the thickest portion of the pressure relaxation layer is the thickness of the pressure relaxation layer.
  • the thickness of the pressure relaxation layer is measured, for example, by observing the cut surface of the lithium ion battery electrode cut perpendicularly to the thickness direction with a digital microscope [VHX-5000, manufactured by Keyence Corporation]. Can do.
  • the pressure relaxation layer disposed between the electrode current collector and the electrode active material layer forms a substantially sponge-like porous layer having a skeleton made of conductive carbon filler and voids. It is thought to form.
  • the expansion of the active material layer caused by lithium ions being taken into the active material generates a force that expands from the inside to the outside of the battery outer body. Therefore, it is possible to suppress the occurrence of defects such as cracks and peeling in the electrode active material layer, so that a lithium ion battery having excellent cycle characteristics can be obtained.
  • 2 (a) and 2 (b) are cross-sectional views schematically showing the state before and after charging / discharging of the electrode active material layer and the pressure relaxation layer constituting the electrode for a lithium ion battery of this embodiment.
  • the electrode 1 for lithium ion batteries shown to Fig.2 (a) and FIG.2 (b) is accommodated in the exterior body 40.
  • FIG. This does not show the actual usage of the lithium ion battery electrode of this embodiment, and the negative electrode and the positive electrode that are electrodes in the lithium ion battery are covered with the battery outer casing, so that free volume expansion is limited. It is for showing that it is being done.
  • FIG. 2A schematically shows the state before the volume expansion of the electrode active material
  • FIG. 2B schematically shows the state after the volume expansion of the electrode active material.
  • the lithium ion battery electrode 1 including the electrode current collector 10, the pressure relaxation layer 20, and the electrode active material layer 30 is accommodated in an exterior body 40. Yes.
  • the thickness of the electrode active material layer 30 is increased from b 1 to b 2. This increase in volume is considered to be largely due to the expansion of the electrode active material contained in the electrode active material layer 30.
  • the electrode active material layer expands toward the pressure relaxation layer, and the thickness of the pressure relaxation layer 20 decreases from a 1 to a 2 . That is, the volume reduction of the electrode active material layer 30 is offset by the volume reduction of the pressure relaxation layer 20, and the volume expansion of the entire electrode can be suppressed.
  • the electrode total thickness of the electrode active material layer and the pressure relief layer before and after the volume expansion of the active material (for a 1 and b 1 in FIGS. 2 (a)
  • the boundary between the pressure relaxation layer 20 and the electrode active material layer 30 is indicated by a wavy line, but the boundary between the pressure relaxation layer 20 and the electrode active material layer 30 is It is not configured to be wavy.
  • the electrode active material constituting the electrode active material layer is present in the vicinity of the surface of the pressure relaxation layer on the electrode active material layer side. 2A and 2B, the wavy lines indicate that the boundary between the pressure relaxation layer 20 and the electrode active material layer 30 is not clear due to the above reason.
  • the pressure relaxation layer is preferably composed of a conductive carbon filler having an electrical resistivity of 50 ⁇ ⁇ m or less. It is preferable that the electrical resistivity of the conductive carbon filler is in the above range because the current generated by the battery reaction of the electrode active material can be transmitted to the negative electrode current collector.
  • Examples of the conductive carbon filler include carbon [graphite and carbon black (acetylene black, ketjen black (registered trademark), furnace black, channel black, thermal lamp black, etc.]), PAN-based carbon fiber, and pitch-based carbon fiber. Carbon fibers, carbon nanofibers and carbon nanotubes.
  • the conductive carbon filler constituting the pressure relaxation layer is at least one selected from the group consisting of carbon fiber, carbon nanofiber and carbon nanotube from the viewpoint of absorbing the volume expansion of the active material layer and from the viewpoint of conductivity. Is more preferable.
  • the aspect ratio of the conductive carbon filler constituting the pressure relaxation layer is not particularly limited, but is preferably 20 to 10,000.
  • the aspect ratio of the conductive carbon filler can be measured by observing the conductive carbon filler using a scanning electron microscope (hereinafter also referred to as SEM).
  • a positive electrode active material or a negative electrode active material can be used as the electrode active material.
  • An electrode current collector when a positive electrode active material is used as an electrode active material is also referred to as a positive electrode current collector, and an electrode current collector when a negative electrode active material is used as an electrode active material is also referred to as a negative electrode current collector.
  • An electrode active material layer when a positive electrode active material is used as an electrode active material is also called a positive electrode active material layer, and an electrode active material layer when a negative electrode active material is used as an electrode active material is also called a negative electrode active material layer.
  • Pressure relief layer constituting a lithium ion battery electrode using a positive electrode active material as a positive electrode pressure relief layer, and pressure relief layer constituting a lithium ion battery electrode using a negative electrode active material as an electrode active material Also called a layer.
  • the electrode active material constituting the electrode for a lithium ion battery of the present invention is a negative electrode active material
  • the negative electrode active material layer is composed of silicon and / or a silicon compound (in the present specification, these are collectively referred to as a silicon-based negative electrode active material).
  • a non-binding body of a mixture comprising a carbon-based negative electrode active material, and a non-binding body of a mixture comprising silicon and / or a silicon compound, a carbon-based negative electrode active material, and an electrolytic solution More preferably, it is a body.
  • the energy density is excellent. Furthermore, since it is a non-binding body and does not contain a binder, it is possible to suppress deterioration of cycle characteristics as described above.
  • the electrolytic solution it is possible to use an electrolytic solution containing an electrolyte and a non-aqueous solvent used in the manufacture of a lithium ion battery.
  • the mass mixing ratio of the total of silicon and silicon compounds contained in the mixture constituting the negative electrode active material layer and the carbon-based negative electrode active material is preferably 5:95 to 35:65.
  • the mass mixing ratio is in the above range, the effect of improving the energy density by silicon and / or silicon compound is sufficient. Moreover, the volume expansion at the time of charge of a negative electrode active material layer does not become large too much.
  • the carbon-based negative electrode active material is a carbon-based coated negative electrode active material, which will be described later, when calculating the mass mixing ratio, the mass of the electrode coating layer constituting the carbon-based coated negative electrode active material is also taken into account.
  • the thickness of the negative electrode active material layer is not particularly limited, but is preferably 100 to 2500 ⁇ m, more preferably 150 to 2000 ⁇ m, and further preferably 200 to 1500 ⁇ m.
  • the electrode By setting the thickness of the negative electrode active material layer in the above range, the electrode can be made thicker than the conventional negative electrode, and the amount of the active material contained in the electrode is increased. Furthermore, since the energy density is increased by including silicon and / or a silicon compound in the negative electrode active material layer, an electrode having a high energy density and a high capacity can be obtained.
  • the thickness of the negative electrode active material layer is obtained by subtracting the thickness of the negative electrode pressure relaxation layer from the total thickness of the negative electrode active material layer and the negative electrode pressure relaxation layer.
  • the thickness of the negative electrode active material layer and the thickness of the negative electrode pressure relaxation layer are determined before the negative electrode active material layer is charged, or the negative electrode active material layer is subjected to an electrode potential value +0.05 V (vs. Li / Li + ) The thickness when discharged to below.
  • the relationship between the thickness of the negative electrode active material layer and the thickness of the negative electrode pressure relaxation layer is not particularly limited, but the thickness of the negative electrode pressure relaxation layer is preferably 0.3 to 25% of the thickness of the negative electrode active material layer. More preferably, it is 2 to 15%.
  • the expansion during charging of the negative electrode active material layer can be absorbed more without lowering the energy density.
  • Silicon may be crystalline silicon, amorphous silicon, or a mixture thereof.
  • silicon compound examples include silicon oxide (SiO x ), Si—C composite, Si—Al alloy, Si—Li alloy, Si—Ni alloy, Si—Fe alloy, Si—Ti alloy, Si—Mn alloy, It is preferably at least one selected from the group consisting of Si—Cu alloys and Si—Sn alloys.
  • Si—C composite examples include silicon carbide, carbon particles whose surfaces are covered with silicon and / or silicon carbide, and silicon particles and silicon oxide particles whose surfaces are covered with carbon and / or silicon carbide. included.
  • composite particles obtained by agglomeration of primary particles that is, primary particles composed of silicon and / or silicon compounds
  • Secondary particles obtained by aggregation may be formed.
  • the composite particles may be agglomerated when primary particles of silicon and / or silicon compound particles are aggregated due to their adsorption force, or when primary particles are aggregated through other materials.
  • Examples of a method for forming composite particles by binding via other materials include, for example, a method of mixing primary particles of silicon and / or silicon compound particles and a polymer compound constituting an electrode coating layer described later Is mentioned.
  • the silicon-based negative electrode active material may be the silicon-based negative electrode active material itself, or a silicon-based coating in which part or all of the surface of the silicon-based negative electrode active material is coated with an electrode coating layer containing a polymer compound. Although it may be a negative electrode active material, it is preferably a silicon-based negative electrode active material.
  • the electrode coating layer that covers part or all of the surface of the silicon-based negative electrode active material is also referred to as a negative electrode coating layer.
  • the volume average particle diameter when the silicon-based negative electrode active material is a silicon-based coated negative electrode active material is the volume average particle diameter of the silicon-based negative electrode active material before the electrode coating layer is formed.
  • the volume average particle diameter of silicon and silicon compounds is not particularly limited, but is preferably 0.2 to 30 ⁇ m from the viewpoint of electrical characteristics.
  • the primary particle diameter is 0.2 to It is preferably 10 ⁇ m
  • the secondary particle diameter is more preferably 10 to 30 ⁇ m.
  • Examples of the carbon-based negative electrode active material include carbon-based materials [for example, graphite, non-graphitizable carbon, amorphous carbon, resin fired bodies (for example, those obtained by firing and carbonizing phenol resin, furan resin, etc.), cokes (for example, pitch) Coke, needle coke, petroleum coke, etc.)], or conductive polymers (such as polyacetylene and polypyrrole), metal oxides (titanium oxide and lithium / titanium oxide), and metal alloys (lithium-tin alloys, lithium- A mixture of an aluminum alloy, an aluminum-manganese alloy, etc.) with a carbon-based material.
  • carbon-based negative electrode active materials those that do not contain lithium or lithium ions may be subjected to a pre-doping treatment in which some or all of the inside contains lithium or lithium ions.
  • the volume average particle diameter of the carbon-based negative electrode active material is preferably 0.01 to 50 ⁇ m, more preferably 0.1 to 25 ⁇ m, and more preferably 2 to 20 ⁇ m, from the viewpoint of electrical characteristics of the negative electrode for a lithium ion battery. Is more preferable.
  • the volume average particle size of silicon, silicon compound and carbon-based negative electrode active material is the particle size (Dv50) at an integrated value of 50% in the particle size distribution determined by the microtrack method (laser diffraction / scattering method).
  • the microtrack method is a method for obtaining a particle size distribution using scattered light obtained by irradiating particles with laser light.
  • Nikkiso Co., Ltd. microtrack etc. can be used for the measurement of a volume average particle diameter.
  • the primary particle diameter is within several to several tens of fields using observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The value calculated as the average value of the particle diameters of the observed particles is adopted.
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • the carbon-based negative electrode active material may be the carbon-based negative electrode active material itself, and a carbon-based coating in which a part or all of the surface of the carbon-based negative electrode active material is coated with an electrode coating layer containing a polymer compound. Although it may be a negative electrode active material, it is preferably a carbon-based coated negative electrode active material. In addition, the electrode coating layer which coat
  • the volume average particle diameter when the carbon-based negative electrode active material is a carbon-based coated negative electrode active material is the volume average particle diameter of the carbon-based negative electrode active material before the electrode coating layer is formed.
  • the negative electrode active material layer contains silicon and / or a silicon compound and a carbon-based negative electrode active material
  • particles composed of silicon and / or a silicon compound and particles composed of a carbon-based negative electrode active material may be mixed and used.
  • Granulated particles containing both silicon and / or a silicon compound and a carbon-based negative electrode active material may be used.
  • the positive electrode active material layer is preferably a non-binding body of a positive electrode active material composition containing a positive electrode active material.
  • the positive electrode active material composition may be only the positive electrode active material, but is more preferably a non-binding body of a mixture of the positive electrode active material and the electrolytic solution.
  • the positive electrode active material layer is a non-binder of the positive electrode active material composition containing the positive electrode active material, the positive electrode active material layer does not contain the binder, and as described above, the deterioration of cycle characteristics is suppressed. Can do.
  • the electrolytic solution it is possible to use an electrolytic solution containing an electrolyte and a non-aqueous solvent used in the manufacture of a lithium ion battery.
  • the positive electrode active material a conventionally known material can be suitably used, which is a compound that can insert and desorb lithium ions by applying a certain potential, and has a higher potential than the negative electrode active material used for the counter electrode.
  • a compound capable of inserting and desorbing lithium ions can be used.
  • a composite oxide of lithium and a transition metal a composite oxide having one kind of transition metal (such as LiCoO 2 , LiNiO 2 , LiAlMnO 4 , LiMnO 2, and LiMn 2 O 4 ), a transition metal element is used.
  • LiFeMnO 4 LiNi 1-x Co x O 2 , LiMn 1-y Co y O 2 , LiNi 1/3 Co 1/3 Al 1/3 O 2 and LiNi 0.8 Co 0.15 Al 0.05 O 2
  • lithium-containing transition metal phosphates eg LiFePO 4 , LiCoPO 4 , LiMnPO 4 and LiNiPO 4
  • transition metal oxides eg MnO 2 and V 2 O 5
  • transition metal sulfides eg MoS 2 and TiS 2
  • conductive polymers eg polyaniline, polypyrrole, polythiophene, polyacetylene.
  • lithium-containing transition metal phosphate may have a transition metal site partially substituted with another transition metal.
  • the volume average particle diameter of the positive electrode active material is preferably 0.01 to 100 ⁇ m, more preferably 0.1 to 35 ⁇ m, and further preferably 2 to 30 ⁇ m from the viewpoint of battery characteristics.
  • the volume average particle diameter of the positive electrode active material means the particle diameter (Dv50) at an integrated value of 50% in the particle size distribution determined by the microtrack method (laser diffraction / scattering method).
  • the positive electrode active material layer may further contain a conductive aid as necessary.
  • the same conductive material as the optional component of the negative electrode coating layer can be suitably used.
  • the positive electrode active material may be the positive electrode active material itself, or may be a coated positive electrode active material in which part or all of the surface of the positive electrode active material is coated with an electrode coating layer containing a polymer compound. Is preferably a coated positive electrode active material.
  • covers part or all of the surface of a positive electrode active material is also called positive electrode coating layer.
  • the thickness of the positive electrode active material layer is not particularly limited, but is preferably 100 to 2500 ⁇ m, more preferably 150 to 2000 ⁇ m, and further preferably 200 to 1500 ⁇ m.
  • the electrode By making the thickness of the positive electrode active material layer in the above range, the electrode can be made thicker than the conventional electrode, and the amount of the active material contained in the electrode is increased.
  • the thickness of the positive electrode active material layer is obtained by subtracting the thickness of the positive electrode pressure relaxation layer from the total thickness of the positive electrode active material layer and the positive electrode pressure relaxation layer.
  • the thickness of the positive electrode active material layer and the thickness of the positive electrode pressure relaxation layer are determined before the discharge of the positive electrode active material layer or when the positive electrode active material layer has an electrode potential value +4.20 V (vs. Li / Li + ) and the thickness when charged to above.
  • the relationship between the thickness of the positive electrode active material layer and the thickness of the positive electrode pressure relaxation layer is not particularly limited, but the thickness of the positive electrode pressure relaxation layer is preferably 0.3 to 25% of the thickness of the positive electrode active material layer. It is more preferably 1 to 20%, further preferably 5 to 10%.
  • the expansion during charging of the positive electrode active material layer can be absorbed more without lowering the energy density.
  • an electrode coating layer that may cover part or all of the surface of the electrode active material will be described.
  • the electrode coating layer includes a polymer compound, and may further include a conductive material as necessary.
  • the coated electrode active material is one in which part or all of the surface of the electrode active material is coated with an electrode coating layer containing a polymer compound.
  • the coated electrode active material layer for example, the coated electrode active material Even if the substances contact each other, the electrode coating layers do not irreversibly adhere to each other on the contact surface, and the adhesion is temporary and can be easily loosened by hand. They are not fixed by the electrode coating layer. Therefore, in the electrode active material layer containing the coated electrode active material, the electrode active materials are not bound to each other.
  • the electrode active material layer contains a binder is to observe whether or not the electrode active material layer collapses when the electrode active material layer is completely impregnated in the electrolytic solution. It can be confirmed with.
  • the electrode active material layer is a binder containing a binder, the shape can be maintained for one minute or longer, but the electrode active material layer is a non-binder containing no binder. The shape collapses in less than 1 minute.
  • the binder contained in the electrode active material layer in the conventional lithium ion battery also includes polymer compounds such as starch, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, and styrene-butadiene rubber.
  • the binder is used by being dissolved or dispersed in water or an organic solvent, and is dried and solidified by volatilizing the solvent component (or dispersion medium component) to form electrode active materials, electrode active material particles, and a current collector. Is firmly fixed to form a negative electrode active material layer.
  • the electrode coating layer covers a part or all of the surface of the electrode active material. As described above, even if the coated electrode active materials are in contact with each other in the negative electrode active material layer, the electrode coating layer is covered on the contact surface. The layers are not firmly bonded and fixed, and the electrode coating layer and the binder are different members.
  • thermoplastic resins and thermosetting resins examples include thermoplastic resins and thermosetting resins.
  • examples thereof include resins, silicone resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, polycarbonates, polysaccharides (such as sodium alginate), and mixtures thereof.
  • acrylic resins, urethane resins, polyester resins and polyamide resins are preferable, and acrylic resins are more preferable.
  • a polymer compound having a liquid absorption rate of 10% or more when immersed in an electrolytic solution and a tensile elongation at break in a saturated liquid absorption state of 10% or more is more preferable.
  • the liquid absorption rate when immersed in the electrolytic solution is obtained by the following equation by measuring the mass of the polymer compound before the immersion in the electrolytic solution and after the immersion.
  • Absorption rate (%) [(mass of polymer compound after immersion in electrolyte ⁇ mass of polymer compound before immersion in electrolyte) / mass of polymer compound before immersion in electrolyte] ⁇ 100
  • the saturated liquid absorption state refers to a state in which the mass of the polymer compound does not increase even when immersed in the electrolyte.
  • the electrolyte solution used when manufacturing a lithium ion battery using the electrode for lithium ion batteries of this invention is not limited to the said electrolyte solution, You may use another electrolyte solution.
  • the liquid absorption rate is 10% or more, lithium ions can easily permeate the polymer compound, so that the ionic resistance in the electrode active material layer can be kept low.
  • the liquid absorption is less than 10%, the lithium ion conductivity is lowered, and the performance as a lithium ion battery may not be sufficiently exhibited.
  • the liquid absorption is preferably 20% or more, and more preferably 30% or more.
  • a preferable upper limit value of the liquid absorption is 400%, and a more preferable upper limit value is 300%.
  • the tensile elongation at break in the saturated liquid absorption state was determined by punching the polymer compound into a dumbbell shape and immersing it in an electrolytic solution at 50 ° C. for 3 days in the same manner as the measurement of the liquid absorption rate.
  • the state can be measured according to ASTM D683 (test piece shape Type II).
  • the tensile elongation at break is a value obtained by calculating the elongation until the test piece breaks in the tensile test according to the following formula.
  • Tensile elongation at break (%) [(length of specimen at break ⁇ length of specimen before test) / length of specimen before test] ⁇ 100 If the tensile elongation at break in the saturated liquid absorption state of the polymer compound is 10% or more, the polymer compound has appropriate flexibility, so that the electrode coating layer peels off due to the volume change of the electrode active material during charge / discharge It becomes easy to suppress.
  • the tensile elongation at break is preferably 20% or more, and more preferably 30% or more. Further, the preferable upper limit value of the tensile elongation at break is 400%, and the more preferable upper limit value is 300%.
  • the acrylic resin is preferably a resin comprising a polymer (A1) having an acrylic monomer (a) as an essential constituent monomer.
  • the polymer (A1) is a monomer composition comprising a monomer (a1) having a carboxyl group or an acid anhydride group as the acrylic monomer (a) and a monomer (a2) represented by the following general formula (1).
  • a polymer is preferred.
  • CH 2 C (R 1 ) COOR 2 (1)
  • R 1 represents a hydrogen atom or a methyl group
  • R 2 represents a straight chain having 4 to 12 carbon atoms or a branched alkyl group having 3 to 36 carbon atoms.
  • Monomers (a1) having a carboxyl group or an acid anhydride group include (meth) acrylic acid (a11), monocarboxylic acids having 3 to 15 carbon atoms such as crotonic acid and cinnamic acid; (anhydrous) maleic acid and fumaric acid Dicarboxylic acids having 4 to 24 carbon atoms such as itaconic acid, citraconic acid and mesaconic acid; polycarboxylic acids having a valence of 6 to 24 carbon atoms such as aconitic acid and the like. Can be mentioned. Among these, (meth) acrylic acid (a11) is preferable, and methacrylic acid is more preferable.
  • R 1 represents a hydrogen atom or a methyl group.
  • R 1 is preferably a methyl group.
  • R 2 is preferably a linear or branched alkyl group having 4 to 12 carbon atoms or a branched alkyl group having 13 to 36 carbon atoms.
  • R 2 is a linear or branched alkyl group having 4 to 12 carbon atoms.
  • linear alkyl group having 4 to 12 carbon atoms include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, Nonyl group, decyl group, undecyl group, dodecyl group can be mentioned.
  • Examples of the branched alkyl group having 4 to 12 carbon atoms include 1-methylpropyl group (sec-butyl group), 2-methylpropyl group, 1,1-dimethylethyl group (tert-butyl group), 1-methylbutyl group, 1 , 1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group (neopentyl group), 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group 1-methylhexyl group, 2-methylhexyl group, 2-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethy
  • R 2 is a branched alkyl group having 13 to 36 carbon atoms
  • the branched alkyl group having 13 to 36 carbon atoms include a 1-alkylalkyl group [1-methyldodecyl group, 1-butyleicosyl group, 1-hexyloctadecyl group, 1-octylhexadecyl group, 1-decyltetradecyl group, 1-undecyltridecyl group, etc.], 2-alkylalkyl group [2-methyldodecyl group, 2-hexyloctadecyl group, 2- Octylhexadecyl group, 2-decyltetradecyl group, 2-undecyltridecyl group, 2-dodecylhexadecyl group, 2-tridecylpentadecyl group, 2-decyloctadecyl group, 2-tetrade
  • the polymer (A1) preferably further contains an ester compound (a3) of a monovalent aliphatic alcohol having 1 to 3 carbon atoms and (meth) acrylic acid.
  • Examples of the monovalent aliphatic alcohol having 1 to 3 carbon atoms constituting the ester compound (a3) include methanol, ethanol, 1-propanol and 2-propanol.
  • the content of the ester compound (a3) is preferably 10 to 60% by mass, and preferably 15 to 55% by mass based on the total mass of the polymer (A1) from the viewpoint of suppressing volume change of the electrode active material. More preferably, it is more preferably 20 to 50% by mass.
  • the polymer (A1) may further contain an anionic monomer salt (a4) having a polymerizable unsaturated double bond and an anionic group.
  • Examples of the structure having a polymerizable unsaturated double bond include a vinyl group, an allyl group, a styryl group, and a (meth) acryloyl group.
  • anionic group examples include a sulfonic acid group and a carboxyl group.
  • An anionic monomer having a polymerizable unsaturated double bond and an anionic group is a compound obtained by a combination thereof, such as vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid and (meth) acrylic acid. It is done.
  • the (meth) acryloyl group means an acryloyl group and / or a methacryloyl group.
  • Examples of the cation constituting the salt (a4) of the anionic monomer include lithium ion, sodium ion, potassium ion and ammonium ion.
  • the content thereof is preferably 0.1 to 15% by mass based on the total mass of the polymer compound from the viewpoint of internal resistance and the like. It is more preferably ⁇ 15% by mass, and further preferably 2-10% by mass.
  • the polymer (A1) preferably contains (meth) acrylic acid (a11) and an ester compound (a21), and more preferably contains an ester compound (a3).
  • methacrylic acid is used as (meth) acrylic acid (a11), 2-ethylhexyl methacrylate is used as ester compound (a21), and methyl methacrylate is used as ester compound (a3).
  • the polymer compound includes (meth) acrylic acid (a11), the monomer (a2), an ester compound (a3) of a monovalent aliphatic alcohol having 1 to 3 carbon atoms and (meth) acrylic acid, and a polymerization used as necessary.
  • a monomer composition comprising a salt (a4) of an anionic monomer having a polymerizable unsaturated double bond and an anionic group, and the monomer (a2) and the (meth) acrylic acid
  • the mass ratio (the monomer (a2) / the (meth) acrylic acid (a11)) of (a11) is preferably 10/90 to 90/10.
  • the mass ratio of the monomer (a2) and the (meth) acrylic acid (a11) is 10/90 to 90/10, the polymer obtained by polymerizing the monomer has good adhesion to the electrode active material and peels off. It becomes difficult.
  • the mass ratio is preferably 30/70 to 85/15, and more preferably 40/60 to 70/30.
  • the monomer constituting the polymer (A1) includes a monomer (a1) having a carboxyl group or an acid anhydride group, a monomer (a2) represented by the above general formula (1), a carbon number of 1 to 3
  • a monomer (a2) represented by the above general formula (1) a carbon number of 1 to 3
  • the ester compound (a3) of a monovalent aliphatic alcohol of (meth) acrylic acid and an anionic monomer salt (a4) having a polymerizable unsaturated double bond and an anionic group As long as the physical properties of the coalescence (A1) are not impaired, the monomer (a1), the monomer (a2) represented by the general formula (1), a monovalent aliphatic alcohol having 1 to 3 carbon atoms and (meth) acrylic
  • a radical polymerizable monomer (a5) that can be copolymerized with an ester compound (a3) with an acid may be contained.
  • the radical polymerizable monomer (a5) is preferably a monomer not containing active hydrogen, and the following monomers (a51) to (a58) can be used.
  • the monool (I) linear aliphatic monool (tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, nonadecyl alcohol, arachidyl alcohol, etc.)
  • aromatic aliphatic monools such as benzyl alcohol
  • (A52) Poly (n 2 to 30) oxyalkylene (carbon number 2 to 4) alkyl (carbon number 1 to 18) ether (meth) acrylate [methanol ethylene oxide (hereinafter abbreviated as EO) 10 mol adduct (meta ) Propylene oxide of acrylate, methanol (hereinafter abbreviated as PO), 10 mol adduct (meth) acrylate, etc.]
  • (a54) Vinyl hydrocarbon (a54-1) Aliphatic vinyl hydrocarbon Olefin having 2 to 18 or more carbon atoms (ethylene, propylene, Butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.), diene having 4 to 10 or more carbon atoms (butadiene, isoprene, 1,4-pentadiene, 1,5-hexadiene, 1,7- Octadiene etc.) (a54-2) Alicyclic vinyl hydrocarbon charcoal 4-18 or more cyclic unsaturated compounds such as cycloalkene (eg cyclohexene), (di) cycloalkadiene [eg (di) cyclopentadiene], terpene (eg pinene and limonene), indene (a54-3) Aromatic vinyl hydrocarbons C8-20 aromatic unsaturated compounds such as s
  • a monomer (a1) having a carboxyl group or an acid anhydride group a monomer (a2) represented by the general formula (1), a monovalent aliphatic alcohol having 1 to 3 carbon atoms and ( The content of the ester compound (a3) with meth) acrylic acid, the salt (a4) of the anionic monomer having a polymerizable unsaturated double bond and an anionic group, and the radical polymerizable monomer (a5)
  • A1) is 0.1 to 80% by mass
  • (a2) is 0.1 to 99.9% by mass
  • (a3) is 0 to 60% by mass
  • (a4) is based on the mass of the combined (A1).
  • the content is preferably 0 to 15% by mass and (a5) is preferably 0 to 99.8% by mass.
  • the liquid absorbency to the electrolyte is good.
  • the preferable lower limit of the number average molecular weight of the polymer (A1) is 3,000, more preferably 50,000, still more preferably 100,000, particularly preferably 200,000, and the preferable upper limit is 2,000,000. It is preferably 1,500,000, more preferably 1,000,000, and particularly preferably 800,000.
  • the number average molecular weight of the polymer (A1) can be determined by gel permeation chromatography (hereinafter abbreviated as GPC) measurement under the following conditions.
  • GPC gel permeation chromatography
  • Apparatus Alliance GPC V2000 (manufactured by Waters) Solvent: Orthodichlorobenzene Reference material: Polystyrene detector: RI Sample concentration: 3 mg / ml
  • Column stationary phase PLgel 10 ⁇ m, MIXED-B 2 in series (manufactured by Polymer Laboratories) Column temperature: 135 ° C
  • the polymer (A1) is a known polymerization initiator ⁇ azo initiator [2,2′-azobis (2-methylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile, etc.)] ,
  • Peroxide initiators benzoyl peroxide, di-t-butyl peroxide, lauryl peroxide, etc.
  • the use amount of the polymerization initiator is preferably 0.01 to 5% by mass, more preferably 0.05 to 2% by mass, based on the total mass of the monomers, from the viewpoint of adjusting the number average molecular weight within a preferable range. More preferably, it is 0.1 to 1.5% by mass, and the polymerization temperature and the polymerization time are adjusted according to the kind of the polymerization initiator, etc., but the polymerization temperature is preferably ⁇ 5 to 150 ° C. (more preferably 30 to 120 ° C.), and the reaction time is preferably 0.1 to 50 hours (more preferably 2 to 24 hours).
  • Examples of the solvent used in the solution polymerization include esters (having 2 to 8 carbon atoms such as ethyl acetate and butyl acetate), alcohols (having 1 to 8 carbon atoms such as methanol, ethanol and octanol), hydrocarbons (having carbon atoms). 4 to 8, such as n-butane, cyclohexane and toluene) and ketones (having 3 to 9 carbon atoms, such as methyl ethyl ketone). From the viewpoint of adjusting the number average molecular weight to a preferred range, the amount used is the sum of the monomers.
  • the mass it is preferably 5 to 900 mass%, more preferably 10 to 400 mass%, further preferably 30 to 300 mass%, and the monomer concentration is preferably 10 to 95 mass%, more preferably 20 to 90% by mass, more preferably 30-80% by mass.
  • Examples of the dispersion medium in emulsion polymerization and suspension polymerization include water, alcohol (for example, ethanol), ester (for example, ethyl propionate), light naphtha and the like, and examples of the emulsifier include higher fatty acid (carbon number 10 to 24) metal salt.
  • alcohol for example, ethanol
  • ester for example, ethyl propionate
  • emulsifier include higher fatty acid (carbon number 10 to 24) metal salt.
  • sulfate metal salt for example, sodium lauryl sulfate
  • ethoxylated tetramethyldecynediol sodium sulfoethyl methacrylate, dimethylaminomethyl methacrylate, etc.
  • the monomer concentration of the solution or dispersion is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, and still more preferably 15 to 85% by mass.
  • the amount of the polymerization initiator used is based on the total mass of the monomers. It is preferably 0.01 to 5% by mass, more preferably 0.05 to 2% by mass.
  • known chain transfer agents such as mercapto compounds (such as dodecyl mercaptan and n-butyl mercaptan) and / or halogenated hydrocarbons (such as carbon tetrachloride, carbon tetrabromide and benzyl chloride) can be used. .
  • the polymer (A1) contained in the acrylic resin is a crosslinking agent (A ′) having a reactive functional group that reacts the polymer (A1) with a carboxyl group ⁇ preferably a polyepoxy compound (a′1) [polyglycidyl ether].
  • Examples of the method of crosslinking the polymer (A1) using the crosslinking agent (A ′) include a method of crosslinking after coating the electrode active material with the polymer (A1). Specifically, the electrode active material is mixed with a resin solution containing the polymer (A1) and the solvent is removed to produce a coated electrode active material in which the electrode active material is coated with the polymer (A1). The solution containing the agent (A ′) is mixed with the coated electrode active material and heated to cause solvent removal and a crosslinking reaction, and the polymer (A1) is crosslinked by the crosslinking agent (A ′). A method of causing a reaction to be a molecular compound on the surface of the electrode active material is mentioned.
  • heating temperature is adjusted according to the kind of crosslinking agent, when using a polyepoxy compound (a'1) as a crosslinking agent, Preferably it is 70 degreeC or more, When using a polyol compound (a'2) Is preferably 120 ° C. or higher.
  • the electrode coating layer may contain a conductive material.
  • the conductive material is selected from conductive materials. Specifically, in addition to the conductive carbon filler described above, a metal [nickel, aluminum, stainless steel (SUS), silver, copper, titanium, etc.] is used. it can.
  • These conductive materials may be used alone or in combination of two or more. Further, these alloys or metal oxides may be used. From the viewpoint of electrical stability, preferably aluminum, stainless steel, conductive carbon filler, silver, copper, titanium and a mixture thereof, more preferably silver, aluminum, stainless steel and conductive carbon filler, still more preferably. It is a conductive carbon filler. Moreover, as these electrically conductive materials, what coated the electroconductive material (metal thing among the above-mentioned electrically conductive materials) by plating etc. around the particulate ceramic material or the resin material may be used. A polypropylene resin kneaded with graphene is also preferable as the conductive material.
  • carbon graphite and carbon black (acetylene black, ketjen black (registered trademark), furnace black, channel black, thermal lamp black, etc.), etc.] is preferable as the conductive carbon filler used for the conductive material.
  • the aspect ratio of the conductive carbon filler used for the conductive material is preferably 1 or more and less than 100.
  • the conductive carbon filler used for the conductive material the same conductive carbon filler used for the pressure relaxant can be suitably used.
  • the conductive carbon filler constituting the pressure relaxation layer and the conductive carbon filler contained in the electrode coating layer are different in location, and therefore can be distinguished by performing an enlarged observation of the electrode.
  • the average particle size of the conductive material is not particularly limited, but is preferably 0.01 to 10 ⁇ m and more preferably 0.02 to 5 ⁇ m from the viewpoint of the electrical characteristics of the lithium ion battery electrode. Preferably, it is 0.03 to 1 ⁇ m.
  • particle diameter means the maximum distance L among the distances between any two points on the particle outline.
  • the value of “average particle size” is the average value of the particle size of particles observed in several to several tens of fields using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The calculated value shall be adopted.
  • the shape (form) of the conductive material is not limited to the particle form, and may be a form other than the particle form, for example, a fibrous conductive material.
  • Fibrous conductive materials include conductive fibers made by uniformly dispersing highly conductive metal and graphite in synthetic fibers, metal fibers made from metal such as stainless steel, and the surface of organic fibers as metal.
  • conductive fibers coated with the conductive fibers whose surfaces of organic substances are coated with a resin containing a conductive substance, and conductive carbon fillers, those having an aspect ratio of 1 to less than 100 are preferable.
  • the average fiber diameter of the fibrous conductive material is preferably 0.1 to 20 ⁇ m.
  • the ratio of the total mass of the polymer compound and the conductive material contained in the electrode coating layer is not particularly limited, but is preferably 25% by mass or less with respect to the mass of the electrode active material.
  • the ratio of the mass of the polymer compound to the mass of the electrode active material is not particularly limited, but is preferably 0.1 to 20% by mass.
  • the ratio of the mass of the conductive material to the mass of the electrode active material is not particularly limited, but is preferably 10% by mass or less.
  • the electrode active material layer may further contain a conductive aid.
  • a conductive support agent is an arbitrary component which may be added to an electrode active material composition, and is distinguished from the conductive material which is an arbitrary component of an electrode coating layer.
  • the same conductive material as the optional component of the electrode coating layer can be suitably used.
  • the material constituting the electrode current collector examples include metal materials such as copper, aluminum, titanium, stainless steel, nickel, and alloys thereof, and calcined carbon, conductive polymer, conductive glass, and the like. Of these, aluminum and copper are more preferable from the viewpoint of weight reduction, corrosion resistance, and high conductivity, and aluminum is preferably used on the positive electrode side and copper is used on the negative electrode side.
  • the electrode current collector may be a resin current collector made of a conductive polymer material.
  • the shape of the electrode current collector is not particularly limited, and may be a sheet-like current collector made of the above material and a deposited layer made of fine particles made of the above material.
  • the thickness of the electrode current collector is not particularly limited, but is preferably 50 to 500 ⁇ m.
  • the conductive polymer material constituting the resin current collector for example, a conductive polymer or a material obtained by adding a conductive agent to the resin as necessary can be used.
  • the same conductive material as the conductive material that is an optional component of the electrode coating layer can be suitably used.
  • Examples of the resin constituting the conductive polymer material include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyether nitrile (PEN), poly Tetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin or a mixture thereof Etc.
  • PE polyethylene
  • PP polypropylene
  • PMP polymethylpentene
  • PCO polycycloolefin
  • PET polyethylene terephthalate
  • PEN polyether nitrile
  • PTFE poly Tetrafluoroethylene
  • SBR polyacrylonitrile
  • PAN polymethyl acrylate
  • PMA polymethyl methacrylate
  • PVdF polyvinylidene fluoride
  • polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferable, and polyethylene (PE), polypropylene (PP) and polymethylpentene are more preferable. (PMP).
  • the lithium ion battery electrode of the present invention for example, after forming a pressure relaxation layer on the electrode current collector, an electrode active material layer is formed on the pressure relaxation layer, and pressurization or the like is performed as necessary. Can be manufactured.
  • a dispersion liquid in which a conductive carbon filler serving as the pressure relaxation layer is dispersed in a solvent at a concentration of 5 to 60% by mass based on the mass of the solvent is applied to the electrode current collector with a coating device such as a bar coater, then dried to remove the solvent, and if necessary, pressed with a press machine, and a conductive material that becomes a pressure relaxation layer on the electrode current collector.
  • a coating device such as a bar coater
  • the electrode active material By applying a dispersion liquid containing an electrode active material on the pressure relaxation layer having voids, the electrode active material enters the voids of the pressure relaxation layer. It can be in a state where an active material exists.
  • the pressure relaxation layer When the pressure relaxation layer is formed by these methods, an infinite number of voids can exist in the pressure relaxation layer, and the volume of the pressure relaxation layer contracts / expands according to the volume expansion / contraction during charging / discharging of the electrode active material layer. Can be easily done.
  • a dispersion liquid in which the electrode active material is dispersed at a concentration of 30 to 60% by mass based on the mass of the solvent is formed on the pressure relaxation layer.
  • a method of drying with a coating machine such as a bar coater, drying to remove the solvent, and pressing with a press if necessary.
  • the pressure relaxation layer obtained by drying the dispersion serving as the pressure relaxation layer and the electrode active material layer obtained by drying the dispersion serving as the electrode active material layer are respectively formed on the electrode current collector and the pressure relaxation layer. It is not necessary to form directly on the surface of the electrode current collector, for example, by laminating a layered product (pressure relaxation layer and electrode active material layer) obtained by applying the above dispersion on the surface of an aramid non-woven fabric and drying on the electrode current collector.
  • the electrode for lithium ion batteries of this invention can be manufactured.
  • the solvent may be removed by suction from the back surface of the surface on which the dispersion liquid is applied. At this time, it is only necessary to remove the solvent in the dispersion to such an extent that it can be separated from the aramid nonwoven fabric while maintaining the shape of the layered product, and it is not necessary to completely remove the solvent in the dispersion.
  • a coated electrode active material for example, in a state where the electrode active material is put in a universal mixer and stirred at 30 to 50 rpm, a polymer solution containing a polymer compound is added over 1 to 90 minutes. It can be obtained by dropping and mixing, further mixing a conductive material as necessary, raising the temperature to 50 to 200 ° C. while stirring, reducing the pressure to 0.007 to 0.04 MPa, and holding for 10 to 150 minutes. .
  • solvent examples include 1-methyl-2-pyrrolidone, methyl ethyl ketone, N, N-dimethylformamide (hereinafter also referred to as DMF), dimethylacetamide, N, N-dimethylaminopropylamine, and tetrahydrofuran.
  • binder used in the dispersion serving as the pressure relaxation layer examples include starch, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, styrene-butadiene rubber, polyethylene, and polypropylene.
  • a counter electrode is combined and housed in a cell container together with a separator, and an electrolytic solution is injected as necessary. It can be manufactured by a sealing method or the like.
  • a bipolar electrode is formed by forming an electrode active material layer made of an active material constituting a counter electrode on the other surface of the electrode current collector in which the pressure relaxation layer and the electrode active material layer are formed on one surface of the electrode current collector.
  • the bipolar electrode is laminated with a separator and accommodated in a cell container, and an electrolytic solution is injected as necessary to seal the cell container.
  • separators examples include polyethylene or polypropylene porous films, laminated films of porous polyethylene films and porous polypropylene, non-woven fabrics made of synthetic fibers (such as polyester fibers and aramid fibers) or glass fibers, and silica on the surfaces thereof.
  • synthetic fibers such as polyester fibers and aramid fibers
  • glass fibers such as glass fibers
  • silica on the surfaces thereof.
  • known separators for lithium ion batteries such as those to which ceramic fine particles such as alumina and titania are attached, may be mentioned.
  • the electrolytic solution it is possible to use an electrolytic solution containing an electrolyte and a non-aqueous solvent used in the manufacture of a lithium ion battery.
  • electrolyte those used in known electrolyte solutions can be used, and preferable examples include lithium salt electrolytes of inorganic acids such as LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 and LiClO 4 , A sulfonylimide-based electrolyte having fluorine atoms such as LiN (FSO 2 ) 2 , LiN (CF 3 SO 2 ) 2 and LiN (C 2 F 5 SO 2 ) 2, and a fluorine atom such as LiC (CF 3 SO 2 ) 3 are used. Examples thereof include a sulfonylmethide-based electrolyte.
  • the electrolyte concentration of the electrolytic solution is not particularly limited, but is preferably 0.5 to 5 mol / L, more preferably 0.8 to 3 mol / L, from the viewpoint of the handleability of the electrolytic solution and the battery capacity. It is more preferably 1 to 2 mol / L.
  • non-aqueous solvent those used in known electrolytic solutions can be used, for example, lactone compounds, cyclic or chain carbonates, chain carboxylates, cyclic or chain ethers, phosphates, nitriles. Compounds, amide compounds, sulfones and the like and mixtures thereof can be used.
  • lactone compound examples include 5-membered rings (such as ⁇ -butyrolactone and ⁇ -valerolactone) and 6-membered lactone compounds (such as ⁇ -valerolactone).
  • cyclic carbonate examples include propylene carbonate, ethylene carbonate and butylene carbonate.
  • chain carbonate examples include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate, and di-n-propyl carbonate.
  • chain carboxylic acid ester examples include methyl acetate, ethyl acetate, propyl acetate, and methyl propionate.
  • cyclic ether examples include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,4-dioxane and the like.
  • chain ether examples include dimethoxymethane and 1,2-dimethoxyethane.
  • phosphate esters include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tripropyl phosphate, tributyl phosphate, tri (trifluoromethyl) phosphate, tri (trichloromethyl) phosphate, Tri (trifluoroethyl) phosphate, tri (triperfluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxaphosphoran-2-one, 2-trifluoroethoxy-1,3,2- Examples include dioxaphospholan-2-one and 2-methoxyethoxy-1,3,2-dioxaphosphoran-2-one.
  • nitrile compounds include acetonitrile.
  • amide compound examples include DMF.
  • sulfone examples include chain sulfones such as dimethyl sulfone and diethyl sulfone, and cyclic sulfones such as sulfolane.
  • the non-aqueous solvent may be used alone or in combination of two or more.
  • lactone compounds Among nonaqueous solvents, lactone compounds, cyclic carbonates, chain carbonates, and phosphates are preferable from the viewpoint of battery output and charge / discharge cycle characteristics. More preferred are lactone compounds, cyclic carbonates and chain carbonates, and particularly preferred are cyclic carbonates or a mixture of cyclic carbonates and chain carbonates. Most preferred is a mixture of ethylene carbonate (EC) and propylene carbonate (PC), a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC), or a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC). It is.
  • EC ethylene carbonate
  • PC propylene carbonate
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • conductive carbon filler (carbon fiber)> Conductive carbon fillers, Eiichi Yasuda, Asao Oya, Shinya Komura, Shigeki Tomonoh, Takashi Nishizawa, Shinsuke Nagata, Takashi Akatsu, CARBON, 50,2012,1432-1434 and Eiichi Yasuda, Takashi Akatsu, Yasuhiro Tanabe, Kazumasa Nakamura, Yasuto It was produced with reference to the production method of Hoshikawa, Naoya Miyajima, TANSO, 255, 2012, pages 254 to 265.
  • a carbon precursor 10 parts by mass of synthetic mesophase pitch AR ⁇ MPH [Mitsubishi Gas Chemical Co., Ltd.] and 90 parts by mass of polymethylpentene TPX RT18 [Mitsui Chemicals Co., Ltd.] were used at a barrel temperature of 310 ° C. under a nitrogen atmosphere
  • a resin composition was prepared by melt-kneading using a single screw extruder. Subsequently, the resin composition was melt-extruded and spun at 390 ° C. The spun resin composition was placed in an electric furnace and held at 270 ° C. for 3 hours under a nitrogen atmosphere to stabilize the carbon precursor. Next, the electric furnace was heated to 500 ° C. over 1 hour and held at 500 ° C.
  • the electric furnace was heated up to 1000 ° C. over 2 hours and held at 1000 ° C. for 30 minutes.
  • 90 parts by mass together with 500 parts by mass of water and 1000 parts by mass of zirconia balls having a diameter of 0.1 mm were pot milled. Placed in a container and ground for 5 minutes. After classification of the zirconia balls, the zirconia balls were dried at 100 ° C. to obtain a carbon fiber as the conductive carbon filler A1.
  • the average fiber diameter of the carbon fiber was 0.3 ⁇ m, and the average fiber length was 26 ⁇ m (the aspect ratio was about 87).
  • the electrical resistivity of the carbon fiber was 50 ⁇ ⁇ m, and the bulk density measured according to JIS K 5101-12-1 was 0.5 g / cm 3 .
  • an initiator solution prepared by dissolving 0.583 parts of 2,2'-azobis (2,4-dimethylvaleronitrile) in 26 parts of ethyl acetate was continuously added using a dropping funnel over 2 hours. Furthermore, the polymerization was continued for 4 hours at the boiling point. After removing the solvent to obtain 582 parts of polymer, 1,360 parts of isopropanol was added to obtain a coating polymer compound solution (1) having a resin solid content concentration of 30% by mass.
  • ⁇ Production Example 3 Production of silicon-coated negative electrode active material particles (N-24)> 69 parts of silicon oxide particles [manufactured by Sigma-Aldrich Japan, volume average particle diameter 2.0 ⁇ m] are put into a universal mixer high speed mixer FS25 [manufactured by Earth Technica Co., Ltd.] and stirred at 720 rpm at room temperature. Then, 33.3 parts of the coating polymer compound solution (1) prepared in Production Example 2 was added dropwise over 10 minutes, and the mixture was further stirred for 5 minutes. Then, the pressure is reduced to 0.01 MPa while maintaining the stirring, and then the temperature is raised to 140 ° C. while maintaining the stirring and the degree of vacuum, and the volatile matter is distilled off by maintaining the stirring, the pressure and the temperature for 8 hours. As a result, silicon-based negative electrode active material particles (N-24) were obtained.
  • ⁇ Production Example 8 Production of silicon oxide particles (N-25) whose surface is coated with carbon> Silicon oxide particles (manufactured by Sigma-Aldrich Japan, volume average particle size 2.0 ⁇ m) are placed in a horizontal heating furnace, and a chemical vapor deposition operation of 1100 ° C./1000 Pa and average residence time of about 2 hours is performed while aeration of methane gas is performed. Silicon-based negative electrode active material particles (volume average particle diameter 2.0 ⁇ m) (N-25), which are silicon oxide particles having a carbon content of 2% by mass and coated with carbon on the surface, were obtained.
  • the obtained powder was classified with a sieve having an opening of 20 ⁇ m to obtain composite particles (volume average particle diameter 30 ⁇ m) (N-26).
  • Example 1 [Preparation of negative pressure relief layer] Prepared by dissolving LiPF 6 at a rate of 1 mol / L in 5 parts of the carbon fiber obtained in Production Example 1 and a mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (volume ratio 1: 1). 95 parts of the electrolyte solution (X) was put into a universal mixer high speed mixer FS25 [manufactured by Earth Technica Co., Ltd.] and stirred at 2000 rpm for 5 minutes at room temperature to obtain a pressure relaxation layer raw material paste.
  • EC ethylene carbonate
  • PC propylene carbonate
  • 174 mg of the pressure relaxation layer raw material paste was dropped onto the exposed surface of a 23 mm aramid non-woven fabric (manufactured by Japan Vilene Co., Ltd.), which is a butyl rubber sheet with a hole of ⁇ 15 mm (hereinafter, referred to as a mask) overlapped.
  • the negative electrode pressure relaxation layer was produced on the aramid nonwoven fabric by removing a part of the electrolyte solution (X).
  • the negative electrode active material slurry is dropped onto the exposed surface of the negative electrode pressure relaxation layer prepared on the aramid nonwoven so as to have a basis weight of 47 mg / cm 2, and suction filtration (reduced pressure) is applied from the back side of the dropped surface to obtain a negative electrode pressure.
  • the negative electrode active material layer was laminated on the negative electrode pressure relaxation layer while putting a part of the negative electrode active material in the voids on the surface of the relaxation layer. Further, by pressing at a pressure of 5 MPa, the negative electrode active material layer and the negative electrode pressure relaxation layer were integrated on the aramid nonwoven fabric to produce a laminate (1) of the negative electrode pressure relaxation layer and the negative electrode active material layer.
  • the thickness of the negative electrode pressure relaxation layer and the negative electrode active material layer was 50 ⁇ m and 550 ⁇ m, respectively.
  • each layer was measured using a contact-type film thickness meter [ABS Digimatic Indicator ID-CX manufactured by Mitutoyo Corporation].
  • a mask is placed on a 2300 mesh stainless steel wire mesh of 23 mm in diameter [manufactured by Sunnet Kogyo Co., Ltd.], 174 mg of the positive electrode pressure relaxation layer raw material paste is dropped, and the electrolyte solution (X) is sucked from the back side of the dropped surface. A part was removed and a positive electrode pressure relaxation layer was produced on a stainless steel wire mesh.
  • the positive electrode active material slurry is dropped onto the positive electrode pressure relaxation layer produced on the stainless steel wire mesh so that the basis weight is 78.0 mg / cm 2, and suction filtration (reduced pressure) is performed from the back surface of the dropped surface.
  • the positive electrode active material layer was laminated on the positive electrode vitality relaxation layer while putting a part of the positive electrode active material in the voids on the surface of the positive electrode pressure relaxation layer. Furthermore, by pressing at a pressure of 5 MPa, the positive electrode active material layer and the positive electrode pressure relaxation layer were integrated on a stainless steel wire mesh to produce a laminate (1) of the positive electrode pressure relaxation layer and the positive electrode active material layer. The thicknesses of the positive electrode pressure relaxation layer and the positive electrode active material layer were 50 ⁇ m and 580 ⁇ m, respectively.
  • the laminate (1) of the negative electrode pressure relaxation layer and the negative electrode active material layer is peeled off from the aramid nonwoven fabric and inserted between the copper foil and the aluminum foil of the laminate cell for cell evaluation, and the negative electrode pressure is applied to the surface of the copper foil. It arrange
  • the laminate (1) of the positive electrode pressure relaxation layer and the positive electrode active material layer was peeled off from the stainless steel wire mesh, and laminated so that the positive electrode active material layer was in contact with the separator placed on the negative electrode active material.
  • the laminate cell is closed so that the aluminum foil in the laminate cell for cell evaluation is covered thereon, and the two sides orthogonal to the first heat-sealed are heat sealed. did.
  • the laminate cell was sealed by heat-sealing the remaining one side while evacuating the inside of the cell using a vacuum sealer, and the positive electrode for the lithium ion battery according to Example 1 and the negative electrode for the lithium ion battery according to Example 1 were prepared.
  • a lithium ion battery according to Example 1 was prepared.
  • Example 2 [Production of Laminate (2) of Negative Electrode Pressure Relaxing Layer and Negative Electrode Active Material Layer]
  • a negative electrode pressure relaxation layer was produced in the same procedure as in Example 1 except that the amount of the negative electrode pressure relaxation layer raw material paste was changed to 104 mg.
  • 9.5 parts by mass of the carbon-based coated negative electrode active material particles (N-11) was changed to 3.4 parts by mass of the carbon-based coated negative electrode active material particles (N-12) obtained in Production Example 6.
  • the silicon particles (volume average particle diameter 5 ⁇ m) (N-21) 0.5 parts by mass were changed to silicon particles (volume average particle diameter 0.2 ⁇ m) (N-22) 1.6 parts by mass, and the total amount was 100 parts by mass.
  • a negative electrode active material slurry was prepared in the same procedure as in Example 1 except that the amount of the electrolytic solution (X) was adjusted so that A laminate (2) of a negative electrode pressure relaxation layer and a negative electrode active material layer was produced in the same procedure as in Example 1 except that the basis weight of the negative electrode active material slurry was changed to 19 mg / cm 2 .
  • the thickness of the negative electrode pressure relaxation layer and the negative electrode active material layer was 30 ⁇ m and 200 ⁇ m, respectively.
  • a mask is placed on a 2300 mesh stainless steel wire mesh of 23 mm in diameter [manufactured by Sunnet Kogyo Co., Ltd.], 104 mg of the positive electrode pressure relaxation layer raw material paste used in Example 1 is dropped, and suction filtration (reduced pressure) is applied from the back side of the dropped surface. Thus, a part of the electrolytic solution (X) was removed, and a positive electrode pressure relaxation layer was produced on the stainless steel wire mesh.
  • the thicknesses of the positive electrode pressure relaxation layer and the positive electrode active material layer were 30 ⁇ m and 550 ⁇ m, respectively.
  • a laminate (1) of a negative electrode pressure relaxation layer and a negative electrode active material layer and a laminate (1) of a positive electrode pressure relaxation layer and a positive electrode active material layer are respectively laminated bodies of a negative electrode pressure relaxation layer and a negative electrode active material layer.
  • a lithium ion battery according to Example 2 including a positive electrode for a lithium ion battery according to Example 2 and a negative electrode for a lithium ion battery according to Example 2 was produced.
  • Example 1 except that the amount of the electrolyte (X) was adjusted to 1.7 parts by mass of silicon particles (volume average particle diameter 1.5 ⁇ m) (N-23) and the total amount was 100 parts by mass.
  • a negative electrode active material slurry was prepared in the same procedure as described above.
  • a laminate (3) of a negative electrode pressure relaxation layer and a negative electrode active material layer was produced in the same procedure as in Example 1 except that the basis weight of the obtained negative electrode active material slurry was changed to 10 mg / cm 2 .
  • the thickness of the negative electrode pressure relaxation layer and the negative electrode active material layer was 2 ⁇ m and 100 ⁇ m, respectively.
  • a mask is placed on a 2300 mesh stainless steel wire mesh of 23 mm in diameter [manufactured by Sunnet Kogyo Co., Ltd.], 7.0 mg of the positive electrode pressure relaxation layer raw material paste used in Example 1 is dropped, and suction filtration is performed from the back side of the dripped surface ( By reducing the pressure, a part of the electrolyte solution (X) was removed, and a positive electrode pressure relaxation layer was produced on the stainless steel wire mesh.
  • the thicknesses of the positive electrode pressure relaxation layer and the positive electrode active material layer were 2 ⁇ m and 300 ⁇ m, respectively.
  • a laminate (1) of a negative electrode pressure relaxation layer and a negative electrode active material layer and a laminate (1) of a positive electrode pressure relaxation layer and a positive electrode active material layer are combined with a laminate (3 ) And the laminate (3) of the positive electrode pressure relaxation layer and the positive electrode active material layer, and the same procedure as in Example 1 was performed, except that the injection amount of the electrolyte (X) was changed to 20 ⁇ L.
  • Example 4> [Preparation of Laminate (4) of Negative Electrode Pressure Relaxing Layer and Negative Electrode Active Material Layer]
  • the conductive carbon filler A1 is changed to the same amount of conductive carbon filler A2, and the electrolytic solution (X) is replaced with the same amount of electrolytic solution (Y) [mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (volume
  • the electrolytic solution was prepared by dissolving LiN (FSO 2 ) 2 at a ratio of 1 mol / L in a ratio of 1: 1)], and the silicon-based coated negative electrode active material prepared in Production Example 3 was used to produce silicon particles (N-21).
  • the negative electrode pressure relaxation layer and the negative electrode active material layer were laminated in the same procedure as in Example 1 except that the material particles (N-24) were changed and the basis weight of the negative electrode active material slurry was changed to 46 mg / cm 2.
  • a body (4) was prepared.
  • the thickness of the negative electrode pressure relaxation layer and the negative electrode active material layer was 50 ⁇ m and 540 ⁇ m, respectively.
  • the positive electrode pressure relaxation layer is the same procedure as in Example 1 except that the conductive carbon filler A1 is changed to the same amount of conductive carbon filler A2 and the electrolytic solution (X) is changed to the same amount of electrolytic solution (Y). Was made.
  • the electrolyte solution (X) was changed to the same amount of electrolyte solution (Y), and the basis weight of the cathode active material slurry was changed to 67.2 mg / cm 2.
  • a laminate (4) of the layer and the positive electrode active material layer was produced.
  • the thicknesses of the positive electrode pressure relaxation layer and the positive electrode active material layer were 50 ⁇ m and 500 ⁇ m, respectively.
  • a laminate (1) of a negative electrode pressure relaxation layer and a negative electrode active material layer and a laminate (1) of a positive electrode pressure relaxation layer and a positive electrode active material layer are combined with a laminate (4 ) And a laminate (4) of a positive electrode pressure relaxation layer and a positive electrode active material layer, and the same procedure as in Example 1 was performed, except that the electrolyte solution (X) was changed to the electrolyte solution (Y).
  • Example 5> [Preparation of Laminate (5) of Negative Electrode Pressure Relaxing Layer and Negative Electrode Active Material Layer]
  • the conductive carbon filler A1 was changed to the same amount of conductive carbon filler A2, the electrolytic solution (X) was changed to the same amount of electrolytic solution (Y), and silicon particles (N-21) were produced in Production Example 8. Examples were changed to silicon-based negative electrode active material particles (N-25), the drop amount of the negative electrode pressure relaxation layer raw material paste was changed to 348 mg, and the basis weight of the negative electrode active material slurry was changed to 46 mg / cm 2. 1 to prepare a laminate (5) of a negative electrode pressure relaxation layer and a negative electrode active material layer. The thicknesses of the negative electrode pressure relaxation layer and the negative electrode active material layer were 100 ⁇ m and 540 ⁇ m, respectively.
  • a positive electrode pressure relaxation layer was produced on a stainless steel wire mesh in the same procedure as in Example 1 except that the electrolytic solution (X) was changed to the same amount of electrolytic solution (Y).
  • a laminate (1) of a negative electrode pressure relaxation layer and a negative electrode active material layer and a laminate (1) of a positive electrode pressure relaxation layer and a positive electrode active material layer are combined with a laminate (5 ) And a laminate (5) of a positive electrode pressure relaxation layer and a positive electrode active material layer, and the same procedure as in Example 1 except that the electrolyte solution (X) was changed to the same amount of electrolyte solution (Y).
  • a lithium ion battery according to Example 5 including the positive electrode for lithium ion batteries according to Example 5 and the negative electrode for lithium ion batteries according to Example 5 was produced.
  • Example 6> [Preparation of Laminate (6) of Negative Electrode Pressure Relaxing Layer and Negative Electrode Active Material Layer] Change the 0.5 parts by mass of silicon particles (volume average particle diameter 5 ⁇ m) (N-21) to 0.5 parts by mass of composite particles (volume average particle diameter 30 ⁇ m) (N-26), and the basis weight of the negative electrode active material slurry
  • a laminated body (6) of the negative electrode pressure relaxation layer and the negative electrode active material layer was produced in the same procedure as in Example 1 except that was changed to 46 mg / cm 2 .
  • the thickness of the negative electrode pressure relaxation layer and the negative electrode active material layer was 50 ⁇ m and 550 ⁇ m, respectively.
  • a positive electrode pressure relaxation layer was prepared in the same procedure as in Example 1 except that the electrolytic solution (X) was changed to the same amount of electrolytic solution (Y).
  • the electrolytic solution (X) was changed to the electrolytic solution (Y), the basis weight of the positive electrode active material slurry was changed to 63.9 mg / cm 2 , and the solution was dropped on the positive electrode pressure relaxation layer.
  • the laminate (6) of the positive electrode pressure relaxation layer and the positive electrode active material layer was prepared by the procedure described above. The thicknesses of the positive electrode pressure relaxation layer and the positive electrode active material layer were 50 ⁇ m and 475 ⁇ m, respectively.
  • a laminate (1) of a negative electrode pressure relaxation layer and a negative electrode active material layer and a laminate (1) of a positive electrode pressure relaxation layer and a positive electrode active material layer are combined with a laminate (6 ) And a laminate (6) of a positive electrode pressure relaxation layer and a positive electrode active material layer, and the same procedure as in Example 1 except that the electrolyte solution (X) was changed to the same amount of electrolyte solution (Y).
  • a lithium ion battery according to Example 6 including the positive electrode for lithium ion batteries according to Example 6 and the negative electrode for lithium ion batteries according to Example 6 was produced.
  • Example 7 [Preparation of laminate (7) of negative electrode pressure relaxation layer and negative electrode active material layer]
  • a negative electrode pressure relaxation layer was produced in the same procedure as in Example 1 except that the amount of the negative electrode pressure relaxation layer raw material paste was changed to 104 mg.
  • 9.5 parts by mass of the carbon-based coated negative electrode active material particles (N-11) was changed to 8.0 parts by mass, and 0.5 parts by mass of silicon particles (volume average particle diameter 5 ⁇ m) (N-21) was changed to 2.0 parts by mass of the composite particles (N-26), the electrolyte solution (X) was changed to the same amount of the electrolyte solution (Y), and the total amount of the electrolyte solution (Y) was 100 parts by mass.
  • a negative electrode active material slurry was prepared in the same procedure as in Example 1 except that the amount was adjusted.
  • a laminate (7) of a negative electrode pressure relaxation layer and a negative electrode active material layer was produced in the same procedure as in Example 1 except that the basis weight of the obtained negative electrode active material slurry was changed to 29 mg / cm 2 .
  • the thickness of the negative electrode pressure relaxation layer and the negative electrode active material layer was 30 ⁇ m and 350 ⁇ m, respectively.
  • Positive Electrode Active Material Layer (7) By overlaying a mask on a 2300 mesh stainless steel wire mesh of 23 mm diameter (manufactured by Sunnet Kogyo Co., Ltd.), dropping the positive electrode active material slurry used in Example 1 on the mask and suction filtering (reducing pressure) from the back surface A positive electrode active material layer (7) was prepared on a stainless steel wire mesh. At this time, the basis weight of the positive electrode active material slurry to be dropped was set to 49.1 mg / cm 2 . The thickness of the positive electrode active material layer was 365 ⁇ m.
  • a laminate (1) of a negative electrode pressure relaxation layer and a negative electrode active material layer and a laminate (1) of a positive electrode pressure relaxation layer and a positive electrode active material layer are combined with a laminate (7 ) And the positive electrode active material layer (7), and the lithium ion according to Example 7 is the same as Example 1, except that the electrolytic solution (X) is changed to the same amount of electrolytic solution (Y).
  • a lithium ion battery according to Example 7 including a battery positive electrode and a lithium ion battery negative electrode according to Example 7 was produced.
  • Example 8> [Preparation of laminate (8) of negative electrode pressure relaxation layer and negative electrode active material layer]
  • the negative electrode pressure relaxation layer and the negative electrode active material were the same as in Example 1, except that the amount of the negative electrode pressure relaxation layer raw material drop was changed to 348 mg and the basis weight of the negative electrode active material slurry was changed to 43 mg / cm 2.
  • a laminate (8) with layers was produced.
  • the thickness of the negative electrode pressure relaxation layer and the negative electrode active material layer was 100 ⁇ m and 550 ⁇ m, respectively.
  • Positive Electrode Active Material Layer (8) By overlaying a mask on a 2300 mesh stainless steel wire mesh of 23 mm diameter (manufactured by Sunnet Kogyo Co., Ltd.), dropping the positive electrode active material slurry used in Example 1 on the mask and suction filtering (reducing pressure) from the back surface A positive electrode active material layer (8) was prepared on a stainless steel wire mesh. At this time, the basis weight of the positive electrode active material slurry to be dropped was set to 71.3 mg / cm 2 . The thickness of the positive electrode active material layer was 530 ⁇ m.
  • a lithium ion battery according to Example 8 including the positive electrode for a lithium ion battery according to Example 8 and the negative electrode for a lithium ion battery according to Example 8 was produced in the same procedure as in Example 7, except that each was changed to .
  • ⁇ Comparative Example 1> [Preparation of Negative Electrode Active Material Layer (1 ′)] 85 parts of the electrolytic solution (X) used in Example 1 and 3.3 parts of carbon-based coated negative electrode active material particles (N-13), silicon particles [manufactured by Sigma-Aldrich Japan, volume average particle diameter 1.5 ⁇ m] (N -23) After adding 1.7 parts of the carbon fiber as the conductive carbon filler A1 and adding 10 parts of an N-methylpyrrolidone solution containing 5% by mass of polyvinylidene fluoride from which water has been removed, stir in the planet A negative electrode active material slurry was prepared by mixing for 1.5 minutes at 2000 rpm using a mold mixing and kneading apparatus ⁇ Awatori Netaro (manufactured by Shinky Co., Ltd.) ⁇ .
  • the obtained negative electrode active material slurry was dropped onto a ⁇ 23 mm aramid nonwoven fabric equipped with a ⁇ 15 mm mask so that the basis weight was 9 mg / cm 2, and was subjected to suction filtration (reduced pressure) from the back side of the dropped surface. A part of the liquid (X) was removed to prepare a negative electrode active material layer. Thereafter, pressing was performed at a pressure of 5 MPa for about 10 seconds, followed by drying at 100 ° C. for 15 minutes to obtain a negative electrode active material layer (1 ′). The thickness of the negative electrode active material layer (1 ′) was 100 ⁇ m.
  • the thickness of the positive electrode active material layer (1 ′) was 270 ⁇ m.
  • a laminate (1) of a negative electrode pressure relaxation layer and a negative electrode active material layer and a laminate (1) of a positive electrode pressure relaxation layer and a positive electrode active material layer are combined into a negative electrode active material layer (1 ′) and a positive electrode active material layer (1 ′).
  • the lithium ion battery according to Comparative Example 1 including the positive electrode for the lithium ion battery according to Comparative Example 1 and the negative electrode for the lithium ion battery according to Comparative Example 1 is manufactured in the same procedure as in Example 1 except that did.
  • the obtained negative electrode active material slurry was dropped onto a ⁇ 23 mm aramid nonwoven fabric equipped with a ⁇ 15 mm mask so that the basis weight was 46 mg / cm 2, and was subjected to suction filtration (reduced pressure) from the back side of the dropped surface. A part of the liquid (Y) was removed to prepare a negative electrode active material layer. Thereafter, pressing was performed at a pressure of 5 MPa for about 10 seconds, followed by drying at 100 ° C. for 15 minutes to obtain a negative electrode active material layer (2 ′). The thickness of the negative electrode active material layer (2 ′) was 540 ⁇ m.
  • a laminate (1) of a negative electrode pressure relaxation layer and a negative electrode active material layer and a laminate (1) of a positive electrode pressure relaxation layer and a positive electrode active material layer are combined into a negative electrode active material layer (2 ′) and a positive electrode active material layer (2 ′).
  • the electrolyte solution (X) was changed to the same amount of the electrolyte solution (Y).
  • the same procedure as in Example 1 was followed to obtain a lithium ion battery positive electrode according to Comparative Example 2 and Comparative Example 2.
  • the lithium ion battery which concerns on the comparative example 2 containing the negative electrode for such lithium ion batteries was produced.
  • the electrode for a lithium ion battery of the present invention has excellent cycle characteristics because the expansion of the electrode is sufficiently suppressed even when an electrode active material that can contribute to an improvement in energy density is used. Recognize.
  • the lithium ion battery electrode of the present invention is particularly useful as an electrode for bipolar secondary batteries and lithium ion batteries used for mobile phones, personal computers, hybrid vehicles and electric vehicles.
  • Electrode for lithium ion batteries 10 Electrode current collector 20 Pressure relaxation layer 30 Electrode active material layer 40 Exterior body

Abstract

Le problème décrit par la présente invention est de fournir une électrode pour une batterie au lithium-ion, et une batterie au lithium-ion, ayant d'excellentes caractéristiques de densité d'énergie et de cycle. La solution selon l'invention porte sur une électrode pour une batterie au lithium-ion qui comprend un collecteur de courant d'électrode et une couche de substance active d'électrode, et est caractérisée en ce que : la couche de substance active d'électrode comprend un corps non lié d'une composition de substance active d'électrode contenant une substance active d'électrode; une couche de libération de pression formée à partir d'une charge de carbone conductrice est disposée entre le collecteur de courant d'électrode et la couche de substance active d'électrode; et la substance active d'électrode est présente à proximité de la surface de la couche de libération de pression qui fait face à la couche de substance active d'électrode.
PCT/JP2017/045490 2016-12-20 2017-12-19 Électrode pour batterie au lithium-ion, et batterie au lithium-ion WO2018117089A1 (fr)

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WO2012051280A2 (fr) * 2010-10-12 2012-04-19 The Research Foundation Of State University Of New York Électrodes en composite, procédés de fabrication, et utilisation de ces électrodes
WO2012140790A1 (fr) * 2011-04-13 2012-10-18 エス・イー・アイ株式会社 Matériau d'électrode pour accumulateur au lithium et accumulateur au lithium
JP2013137887A (ja) * 2011-12-28 2013-07-11 Harima Chemicals Inc 電極用組成物、二次電池用電極および電極用緩衝材
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