WO2020129879A1 - Mélange d'électrode négative de batterie au lithium-ion tout solide et batterie au lithium-ion tout solide - Google Patents

Mélange d'électrode négative de batterie au lithium-ion tout solide et batterie au lithium-ion tout solide Download PDF

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WO2020129879A1
WO2020129879A1 PCT/JP2019/049107 JP2019049107W WO2020129879A1 WO 2020129879 A1 WO2020129879 A1 WO 2020129879A1 JP 2019049107 W JP2019049107 W JP 2019049107W WO 2020129879 A1 WO2020129879 A1 WO 2020129879A1
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negative electrode
composite
solid
ion battery
mass
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PCT/JP2019/049107
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Japanese (ja)
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武内　正隆
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昭和電工株式会社
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • 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 electrolyte-free, high energy density all-solid-state lithium-ion battery, and more particularly to a negative electrode mixture material for all-solid-state lithium-ion batteries.
  • Lithium-ion batteries have high voltage and high energy density and are widely used.
  • studies on all-solid-state lithium-ion batteries using a solid electrolyte that does not leak and does not leak in place of the organic electrolyte have been actively studied.
  • JP, 2011-181260, A JP 2013-16423 A (US Pat. No. 9,172,113, US Pat. No. 9,845,597) JP, 2013-41749, A JP-A-2005-191864 (US Patent Publication No. 2017/0237115) JP, 2017-27886, A
  • lithium titanate Li 4 Ti 5 O 12
  • Patent Document 4 discloses that two or more kinds of materials are mixed and used as a negative electrode active material, but the optimum particle size of the solid electrolyte to be used, the physical properties of the materials, and the like are not examined, There was room for improvement.
  • Patent Document 5 discloses a negative electrode material in which fine particles containing Si element or Sn element are dispersed in a carbon matrix.
  • the average particle size of fine particles containing an active Si element or Sn element is too small as 11 nm or less, and a large amount of oxide is generated on the surface, so that the initial Coulombic efficiency is low, and the complex with the carbon matrix is insufficient. Charge/discharge cycle characteristics were insufficient.
  • an object of the present invention is to improve the above-mentioned problems of the prior art and provide a negative electrode mixture material for an all-solid-state lithium-ion battery that can obtain an all-solid-state lithium-ion battery with high capacity, high Coulombic efficiency and high cycle characteristics. And to provide an all-solid-state lithium-ion battery using the negative electrode mixture.
  • the present invention provides the following negative electrode composite material for all-solid-state lithium-ion batteries and all-solid-state lithium-ion batteries.
  • a negative electrode material containing a composite (A) containing silicon-containing particles and a carbonaceous material, and one or more components (B) selected from a carbonaceous material and graphite, and a solid electrolyte The silicon-containing particles of the composite (A) have an average diameter Dav represented by the following formula (1) of 15 nm or more and 150 nm or less, a negative electrode composite material for an all-solid-state lithium-ion battery.
  • Silicon-containing particles are contained in an amount of 25.0 mass% or more and 75.0 mass% or less with respect to 100.0 mass% of the composite (A), and the volume-based accumulation of the composite (A).
  • the negative electrode material contains the composite (A) in an amount of 5.0% by mass or more and 70% by mass or less based on 100% by mass of the total of the composite (A) and the component (B).
  • An all-solid-state lithium-ion battery including a solid electrolyte layer, a negative electrode, and a positive electrode, wherein the negative electrode uses the negative-electrode mixture for all-solid-state lithium-ion battery according to any one of [1] to [11].
  • An all-solid-state lithium-ion battery characterized by being formed.
  • the negative electrode is a composite (A) of silicon-containing particles and a carbonaceous material (hereinafter abbreviated as “composite (A)”). It is possible to obtain an all-solid-state lithium-ion battery having high capacity, high Coulombic efficiency and high cycle characteristics.
  • composite (A) silicon-containing particles and a carbonaceous material
  • the durability can be improved and the capacity can be increased.
  • adhering various kinds of carbon, metal oxides, solid electrolyte particles and the like to the surface of the coating layer (coating layer) of the carbonaceous material cycle characteristics can be improved.
  • the negative electrode composite material for the all-solid-state lithium-ion battery of the present invention (hereinafter, also simply referred to as the “negative electrode composite material of the present invention” or the “negative-electrode composite material”) and the all-solid-state lithium-ion battery will be described in detail.
  • the oxygen content of the silicon-containing particles is preferably 1.0% by mass or more, more preferably 2.0% by mass or more, from the viewpoint of sufficiently suppressing oxidation. Further, the oxygen content is preferably 15.0 mass% or less from the viewpoint of increasing the initial Coulombic efficiency.
  • the oxygen content can be quantified by, for example, an oxygen-nitrogen simultaneous analyzer (inert gas melting-infrared absorption method).
  • the silicon-containing particles are preferably particles having a 90% diameter in the number-based cumulative distribution of primary particle diameters of 200 nm or less.
  • the primary particle size can be measured by observation with a microscope such as SEM or TEM.
  • the primary particle size of the composite silicon-containing particles can be calculated by image analysis of 200 images of spherical particles observed with a transmission electron microscope at a magnification of 100,000.
  • Dav is an average diameter (nm) assuming that the silicon-containing particles are dense spheres
  • Ssa is a BET specific surface area (m 2 /g) of the silicon-containing particles
  • ⁇ is a true value of silicon. It is a theoretical value of density (2.33 g/cm 3 ).
  • the average diameter Dav is 15 nm or more, the SiO x content due to surface oxidation is suppressed, and the reversible capacity during the initial charge/discharge cycle of the battery increases. Further, the dispersibility in the composite with the carbonaceous material is good, the degree of expansion and contraction of the composite becomes small at the time of Li insertion and desorption during charge and discharge, and deterioration due to the collapse of the composite does not easily occur. From the same viewpoint, the average diameter Dav is preferably 25 nm or more, more preferably 35 nm or more.
  • the average diameter Dav of the silicon-containing particles is 150 nm or less, the reaction of the silicon-containing particles themselves at the time of Li insertion and desorption during charge and discharge becomes uniform, and local expansion and deterioration due to particle collapse hardly occur.
  • the average diameter Dav is preferably 120 nm or less, more preferably 100 nm or less.
  • the silicon-containing particles can contain, in addition to silicon, an element M selected from other metal elements and metalloid elements (such as carbon element).
  • an element M selected from other metal elements and metalloid elements (such as carbon element).
  • the element M include nickel, copper, iron, tin, aluminum, cobalt and the like.
  • the content of the element M is not particularly limited as long as it does not significantly inhibit the action of silicon, and is, for example, 1 mol or less per 1 mol of silicon atom.
  • the silicon-containing particles are not particularly limited by the manufacturing method.
  • it can be manufactured by the method disclosed in WO2012/000858A1.
  • the carbonaceous material in the composite (A) is a carbon material in which the growth of crystals formed by carbon atoms is low, and includes a carbon material that is not graphite. It has a peak near 1360 cm ⁇ 1 by Raman scattering.
  • the carbonaceous material can be produced, for example, by carbonizing a carbonaceous material precursor.
  • the carbonaceous material precursor is not particularly limited, various polymer materials such as phenol resin, thermal heavy oil, pyrolysis oil, straight asphalt, blown asphalt, petroleum tar by-produced during ethylene production, petroleum pitch, coal Coal tar, a heavy component obtained by removing low boiling point components of coal tar by distillation, and coal tar pitch (coal pitch) are preferable, and petroleum pitch or coal pitch is particularly preferable.
  • Petroleum pitch and coal pitch are a mixture of a plurality of polycyclic aromatic compounds. When petroleum pitch or coal pitch is used, a carbonaceous material having a high carbonization rate and few impurities can be produced. Since petroleum pitch and coal pitch have a low oxygen content, the silicon-containing particles are less likely to be oxidized when the silicon-containing particles are coated with the carbonaceous material.
  • the softening point of the carbonaceous material precursor is preferably 80°C or higher.
  • the softening point is 80° C. or higher, the polycyclic aromatic compound constituting the softening point has a sufficiently large average molecular weight and a small volatile content, so that the carbonization rate becomes low and the specific surface area is controlled within an appropriate range. ..
  • the softening point is preferably 300° C. or lower. When the softening point is 300° C. or lower, the viscosity is low and it tends to be uniformly mixed with the silicon-containing particles.
  • the softening point of the carbonaceous material precursor can be measured by the Mettler method described in ASTM-D3104-77.
  • the carbonaceous material precursor has a residual carbon rate of preferably 20% by mass or more, and more preferably 25% by mass or more, from the viewpoint of appropriately covering the surface. Further, the residual coal rate is preferably 70% by mass or less, more preferably 60% by mass or less, from the viewpoint of uniformly mixing with the silicon-containing particles without causing the viscosity to become too high.
  • Residual coal rate is determined by the following method.
  • the solid carbonaceous material precursor is pulverized in a mortar or the like, and the pulverized product is subjected to mass thermal analysis under nitrogen gas flow.
  • the ratio of the mass at 1100°C to the charged mass is defined as the residual coal rate.
  • the residual coal rate corresponds to the fixed carbon amount measured at a carbonization temperature of 1100°C according to JIS K2425.
  • the carbonaceous material precursor has a QI (quinoline insoluble content) content of preferably 10.00 mass% or less, more preferably 5.00 mass% or less, and further preferably 2.00 mass% or less.
  • the QI content of the carbonaceous material precursor is a value corresponding to the amount of free carbon.
  • the negative electrode material according to one embodiment of the present invention preferably contains the composite (A), and at least a part of the silicon-containing particles and the carbonaceous material in the composite (A) are preferably composite with each other. ..
  • the complexing can include, for example, a state in which silicon-containing particles are fixed and bonded by a carbonaceous material, or a state in which the silicon-containing particles are covered with a carbonaceous material.
  • the 50% diameter (D50) in the volume-based cumulative particle size distribution is preferably 2.0 ⁇ m or more, more preferably 4.0 ⁇ m or more.
  • the D50 is 2.0 ⁇ m or more, handling such as coating is excellent, a portion where the active silicon-containing particles are not covered with the carbonaceous material is less likely to occur, the initial Coulombic efficiency is high, and the charge/discharge cycle life is long.
  • the D50 is preferably 18.0 ⁇ m or less, more preferably 10.0 ⁇ m or less.
  • the D50 is 18.0 ⁇ m or less, the input/output characteristics are high, the uniform distribution in the electrode is excellent, and the expansion is uniform, so that the cycle characteristics are improved. That is, by setting D50 within the above range, it is possible to manufacture with good economy, and the initial Coulomb efficiency, input/output characteristics, and cycle characteristics are improved.
  • the D50 represents the diameter at the time of 50% accumulation measured on a volume basis by a laser diffraction type particle size distribution meter, and indicates the apparent diameter of the particles.
  • a laser diffraction type particle size distribution meter for example, Malvern Mastersizer (registered trademark) can be used.
  • the BET specific surface area is preferably 2.0 m 2 /g or more, more preferably 4.0 m 2 /g or more.
  • the BET specific surface area is preferably 10.0 m 2 /g or less, more preferably 8.0 m 2 /g or less.
  • the BET specific surface area is 10.0 m 2 /g or less, handling such as coating is facilitated, the amount of binder required for electrode preparation is suppressed, the electrode density is easily increased, and the energy density of the battery is improved. ..
  • carbon black is preferably attached to a part or all of the surface of the composite (A). This reduces the contact resistance with other materials in the negative electrode and improves the initial conductivity of the negative electrode. Further, the increase in battery resistance after repeating the charge/discharge cycle is small.
  • the carbon black used is not particularly limited, but Denka Black (registered trademark) (manufactured by Denki Kagaku Kogyo Co., Ltd.), Ketjen Black (registered trademark) (manufactured by Lion Corporation), “Super C65” manufactured by TIMCAL, Super C45" manufactured by TIMCAL is used. The adherence of carbon black can be confirmed by SEM observation and Raman spectroscopic analysis.
  • graphene is attached to a part or all of the surface of the composite (A). This lowers the contact resistance with other materials in the negative electrode, improves not only the conductivity of the negative electrode in the initial stage, but also relaxes the expansion and contraction of the silicon-containing particles during charging and discharging. It is possible to suppress deterioration of contact property with particles. Adhesion of graphene can be confirmed by TEM observation and Raman spectroscopic analysis.
  • the silicon-containing particles and the carbon material (C) in the composite (A) are collectively made into the carbon material (C), the silicon-containing particles and the carbon material (C) in the composite (A).
  • the content of silicon-containing particles is 25 with respect to 100.0 mass% of the composite (A). It is preferably contained in an amount of 0.0% by mass or more, more preferably 35.0% by mass. Further, it is preferable that the silicon-containing particles are contained in an amount of 75.0% by mass or less based on 100% by mass of the composite (A).
  • the volume change due to the insertion and desorption of lithium ions tends to be suppressed, and the surface of the silicon-containing particles may be sufficiently covered with the carbon material (C). Therefore, the conductivity is sufficiently imparted to silicon, the effect of suppressing the surface reactivity of silicon and the effect of relaxing expansion and contraction are enhanced, and the cycle characteristics tend to be improved.
  • silicon-containing particles are contained in an amount of 25.0% by mass or more and 75.0% by mass or less based on 100.0% by mass of the composite (A), It is more preferable that D50, which is the 50% diameter in the volume-based cumulative particle size distribution, is 2 ⁇ m or more and 18 ⁇ m or less.
  • the metal oxide adheres to a part or all of the surface of the composite (A). This improves the contact with the solid electrolyte particles.
  • the metal oxide to be attached is preferably electrochemically inactive fine particles. More preferably, the metal oxide is at least one selected from alumina-based oxides, magnesia-based oxides, and titania-based oxides.
  • lithium titanate fine particles adhere to a part or all of the surface of the composite (A).
  • the contact property with the solid electrolyte particles is improved, and at the same time, lithium titanate performs Li insertion/desorption at a potential about 1 V higher than the Li insertion/desorption potential of the silicon-containing particles.
  • the overvoltage is reduced, and the quick charge characteristics and low temperature characteristics are improved.
  • the adherence of the metal oxide can be confirmed by SEM-EDX observation.
  • the 50% diameter in the number-based cumulative distribution of the metal oxide is preferably 5 nm or more, more preferably 10 nm or more. When the 50% diameter is 5 nm or more, dispersibility and adhesion are good.
  • the 50% diameter is preferably 1000 nm or less, more preferably 500 nm or less. If the 50% diameter is 1000 nm or less, it is easy to uniformly adhere.
  • the 50% diameter in the number-based cumulative distribution can be obtained by observing with an electron microscope at a magnification of 100,000, optionally extracting 200 primary particles, and quantifying by image analysis.
  • the negative electrode material according to one embodiment of the present invention comprises a composite (A) of silicon-containing particles and a carbonaceous material, and such a composite (A) can be manufactured according to a known method.
  • a composite (A) is obtained by a method including mixing silicon-containing particles with the above-mentioned carbonaceous material precursor, and heat-treating the obtained mixture to form the carbonaceous material precursor into a carbonaceous material. be able to.
  • the mixture of the silicon-containing particles and the carbonaceous material precursor melts, for example, one of the carbonaceous material precursors, the molten pitch, the silicon-containing particles, and, if necessary, the above-described carbon black or graphene.
  • Metal oxides and other deposits are mixed in an inert gas atmosphere, the mixture is crushed, and a mechanochemical treatment is performed, or a carbonaceous material precursor is dissolved in a solvent and silicon is produced in the liquid phase. It can be obtained by adding and mixing the contained particles and then pulverizing.
  • a known device such as Hybridizer (registered trademark) manufactured by Nara Machinery Co., Ltd. can be used.
  • the negative electrode material according to one embodiment of the present invention may be manufactured by further adding and mixing carbon black in the step of obtaining a mixture of silicon-containing particles and a carbonaceous material precursor.
  • the amount of carbon black added is preferably 0.2% by mass or more, and more preferably 0.4% by mass or more, based on 100% by mass of the total of the silicon-containing particles and the carbonaceous material precursor. If the addition amount is 0.2% by mass or more, the above-mentioned effect is easily obtained.
  • the addition amount is preferably 10.0% by mass or less, more preferably 5% by mass or less.
  • the addition amount is 10.0 mass% or less, not only the charge/discharge capacity per mass of the composite (A) can be maintained high, but also the ion conduction network of the solid electrolyte is not hindered, and the ionic conductivity of the entire battery is improved. It is possible to maintain high sex.
  • the negative electrode material according to one embodiment of the present invention may be manufactured by further adding and mixing graphene in the step of obtaining a mixture of silicon-containing particles and a carbonaceous material precursor.
  • the amount of graphene added is preferably 0.2% by mass or more and more preferably 0.4% by mass or more based on 100% by mass of the total of the silicon-containing particles and the carbonaceous material precursor. When the added amount is 0.2% by mass or more, the above-mentioned effects are easily obtained.
  • the addition amount is preferably 10.0% by mass or less, more preferably 5.0% by mass or less.
  • the addition amount is 10.0 mass% or less, not only the charge/discharge capacity per mass of the composite (A) can be maintained high, but also the ion conduction network of the solid electrolyte is not hindered, and the ionic conductivity of the entire battery is improved. It is possible to maintain high sex.
  • the negative electrode material according to one embodiment of the present invention may be manufactured by further adding and mixing a metal oxide in the step of obtaining a mixture of silicon-containing particles and a carbonaceous material precursor.
  • the addition amount of the metal oxide is preferably 0.2% by mass or more, and more preferably 0.4% by mass or more, based on 100% by mass of the total of the silicon-containing particles and the carbonaceous material precursor. If the addition amount is 0.2% by mass or more, the above-mentioned effect is easily obtained.
  • the addition amount is preferably 10.0% by mass or less, more preferably 5.0% by mass or less.
  • the addition amount is 10.0 mass% or less, not only the charge/discharge capacity per mass of the composite (A) can be maintained high, but also the ion conduction network of the solid electrolyte is not hindered, and the ionic conductivity of the entire battery is improved. It is possible to maintain high sex.
  • Known devices such as a ball mill, a jet mill, a rod mill, a pin mill, a rotary cutter mill, a hammer mill, an atomizer, and a mortar can be used for pulverization and mixing, but a method that does not increase the degree of oxidation of silicon-containing particles can be used. It is preferable to adopt it, and generally, it is considered that the smaller particle size particles having a larger specific surface area are more likely to proceed, so that the crushing of the large particle size particles preferentially proceeds, and the crushing of the small particle size particles does not proceed much. A device is preferred.
  • the impact force tends to be transmitted to large-sized particles preferentially, and not so much to small-sized particles.
  • a means such as a pin mill or a rotary cutter mill that mainly crushes by impact and shear the shearing force is preferentially transmitted to large-sized particles, and not so much to small-sized particles.
  • the composite (A) can be obtained by using such a device and pulverizing or mixing the silicon-containing particles without promoting the oxidation.
  • the non-oxidizing atmosphere include an atmosphere filled with an inert gas such as argon gas and nitrogen gas.
  • the heat treatment for converting the carbonaceous material precursor into a carbonaceous material is preferably performed at a temperature of 200°C or higher and 1100°C or lower, more preferably 500°C or higher and 1050°C or lower, and particularly preferably 600°C or higher and 1050°C or lower.
  • the carbonaceous material can coat the silicon-containing particles, and the carbonaceous material can be brought into a form in which the carbonaceous material penetrates and is connected to each other. If the heat treatment temperature is too low, carbonization of the carbonaceous material precursor may not be completed sufficiently, and hydrogen and oxygen may remain in the negative electrode material, which may adversely affect the battery characteristics.
  • the heat treatment is preferably performed in a non-oxidizing atmosphere.
  • the non-oxidizing atmosphere include an atmosphere filled with an inert gas such as argon gas and nitrogen gas. Since a lump may be formed by fusion due to heat treatment, it is preferable to disintegrate the heat-treated product in order to use it as an electrode active material.
  • a crushing method a pulsarizer using an impact force of a hammer or the like, a jet mill using collision of objects to be crushed, and the like are preferable.
  • the composite (A) and the carbonaceous material precursor may be mixed and the resulting mixture may be heat-treated to form the composite (A) coated with the carbonaceous material.
  • the surface of the composite (A) with the carbonaceous material it is possible to reliably provide the surface with the carbonaceous material layer containing no silicon-containing particles.
  • the carbonaceous material precursor and the heat treatment conditions for coating the surface of the composite (A) with the carbonaceous material the same carbonaceous precursor and conditions as those used in the production of the composite (A) can be adopted.
  • the surface of graphite is covered with a carbonaceous material.
  • a carbonaceous material By covering the surface of the graphite with the carbonaceous material, the affinity with the solid electrolyte is increased and the dispersion in the electrode is improved.
  • the method of coating the carbonaceous material is not limited, and examples thereof include a method of depositing a carbonaceous material precursor on the surface of the composite and firing it in an inert gas atmosphere at a temperature range of 900 to 1500°C.
  • the carbonaceous material precursor is preferably petroleum pitch or coal pitch.
  • the amount of the carbonaceous material precursor added is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and further preferably 0.2 parts by mass or more with respect to 100 parts by mass of graphite.
  • the amount is preferably 0.5 parts by mass or more, and from the viewpoint that the energy density tends to be excellent, preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and further preferably 2.0 parts by mass or less. Is.
  • the carbonaceous material precursor can be mixed with a solvent to form a liquid, mixed and kneaded with graphite, and then the solvent is volatilized and a baking treatment is performed to coat the surface of the graphite with the carbonaceous material. Further, a method of simply mixing the carbonaceous material precursor and graphite and heat-treating it may be used.
  • 50% diameter D50 in the volume-based cumulative particle size distribution is preferably 0.1 ⁇ m or more, more preferably 1 ⁇ m or more, further preferably 5 ⁇ m or more.
  • the D50 is preferably 10 ⁇ m or less.
  • the D50 is 10 ⁇ m or less, good contact between the solid electrolyte particles and the negative electrode active material can be maintained, the resistance value of the electrode decreases, and the charge/discharge rate characteristics improve.
  • Volume-based cumulative particle size distribution can be measured using a laser diffraction particle size distribution measuring device.
  • a laser diffraction particle size distribution measuring device For example, Malvern Mastersizer (registered trademark) can be used.
  • the type of solid electrolyte is not limited, and the effects of the present invention can be exhibited by using a known solid electrolyte.
  • the solid electrolyte according to one embodiment of the present invention uses, for example, an oxide solid electrolyte or a sulfide solid electrolyte.
  • sulfide-based solid electrolyte examples include sulfide glass, sulfide glass ceramic, and Thio-LISICON type sulfide. Of these sulfide-based solid electrolytes, it is preferable to select a sulfide-based solid electrolyte that can be stably used even if the negative electrode potential is low.
  • the battery performance of an all-solid-state lithium-ion battery is further improved by combining a solid electrolyte that can be used stably even with a low negative electrode potential with the negative electrode active material of the present invention.
  • the above solid electrolyte may be used alone or in combination of two or more. It is more preferable to use a sulfide-based solid electrolyte for the solid electrolyte according to one embodiment of the present invention.
  • the solid electrolyte layer constituting the all-solid-state lithium-ion battery of the present invention is not particularly limited as long as it is a layer containing a solid electrolyte, and can be appropriately selected according to the purpose.
  • the solid electrolyte is preferably the same as that used for the negative electrode.
  • the positive electrode constituting the all-solid-state lithium-ion battery of the present invention is not particularly limited as long as it is a layer containing a positive electrode material, and can be appropriately selected according to the purpose.
  • the positive electrode mixture layer preferably contains a solid electrolyte, and more preferably contains a conductive auxiliary agent.
  • the solid electrolyte is more preferably the same as that used for the negative electrode mixture.
  • a known positive electrode active material can be used as the positive electrode material.
  • rock salt type layered active materials such as LiCoO 2 , LiMnO 2 , LiNiO 2 , LiVO 2 , LiNi 1/3 Mn 1/3 Co 1/3 O 2 , spinel type active materials such as LiMn 2 O 4 , LiFePO 4 ,
  • An olivine-type active material such as LiMnPO 4 , LiNiPO 4 , LiCuPO 4 or a sulfide active material such as Li 2 S can be used. These can be used alone or in a mixture.
  • the D50 which is the 50% diameter in the volume-based cumulative particle size distribution of the positive electrode material, is preferably 2 ⁇ m or more, more preferably 3 ⁇ m or more.
  • the D50 is preferably 15 ⁇ m or less, more preferably 10 ⁇ m or less.
  • the particle size of the positive electrode active material is preferably close to that of the solid electrolyte.
  • the method for producing the solid electrolyte particles, and the means for mixing each positive electrode material, the negative electrode material, the solid electrolyte particles and the conductive auxiliary agent are not particularly limited, but in addition to homogenization using a mortar, a planetary mill, a ball mill, a vibration Mechanical milling can be performed using a mill, Mechanofusion (registered trademark), or the like.
  • an aluminum foil can be used for the positive electrode and a nickel foil or a copper foil can be used for the negative electrode. Both rolled foil and electrolytic foil can be used for the current collector. A carbon-coated aluminum foil or nickel foil can also be used as the current collector.
  • the method of carbon coating is not particularly limited.
  • the carbon contained in the carbon coat layer is not particularly limited, and acetylene black, Ketjen Black (registered trademark), carbon nanotube, graphene, vapor grown carbon fiber, artificial graphite fine powder, or the like can be used.
  • ICP inductively coupled plasma
  • Petroleum pitch (softening point 220° C.) was used.
  • the residual coal ratio at 1100° C. of the petroleum pitch measured by thermal analysis under a nitrogen gas flow was 52% by mass.
  • the QI content of the petroleum pitch measured by the method described in JIS K2425 or a method similar thereto was 0.62% by mass, and the TI content was 48.9% by mass.
  • D50 ( ⁇ m), which is the 50% diameter in the volume-based cumulative particle size distribution, was measured by a wet method using water as a solvent, using a Malvern Mastersizer (registered trademark) as a laser diffraction particle size distribution measuring device.
  • the graphite crystal plane spacing d002 was calculated using the following powder X-ray diffraction (XRD) method. Fill a glass sample plate (sample plate window 18 ⁇ 20 mm, depth 0.2 mm) with a mixture of the sample and standard silicon (NIST) in a mass ratio of 9:1, and measure under the following conditions: I went.
  • XRD device Rigaku's SmartLab
  • X-ray type Cu-K ⁇ ray
  • K ⁇ ray removal method Ni filter
  • X-ray output 45kV, 200mA
  • Scan speed 2.0 deg. /Min.
  • orientation index was calculated by calculating the intensity ratio I(110)/I(004) of the diffraction peaks belonging to the (110) plane and (004) plane of graphite by using the powder X-ray diffraction (XRD) method. evaluated.
  • sample plate made of sample glass (sample plate window 18 ⁇ 20 mm, depth 0.2 mm) was filled, and measurement was performed under the following conditions.
  • XRD device Rigaku's SmartLab
  • X-ray type Cu-K ⁇ ray
  • K ⁇ ray removal method Ni filter
  • X-ray output 45kV, 200mA
  • Measuring range 5.0-100.0 deg
  • Scan speed 2.0 deg. /Min
  • (110) plane 76.5 to 78.0 deg.
  • ⁇ Content of silicon-containing particles The amount of carbon material (C) contained in the composite (A) was measured using a carbon/sulfur analyzer EMIA-920V (manufactured by Horiba Ltd.). The content of silicon-containing particles was determined by subtracting the amount of carbon material (C) from the amount of composite (A).
  • the test was conducted in a constant temperature bath set at 25°C. At this time, the capacity at the time of initial discharge was taken as the initial discharge capacity.
  • the ratio of the amount of electricity during the initial charge/discharge, that is, the amount of discharged electricity/the amount of charged electricity was expressed as a percentage, and the result was taken as the initial Coulombic efficiency.
  • This silicon-containing particle (1)/petroleum pitch/carbon black mixture was put into a firing furnace, and the temperature was raised to 1100° C. at 150° C./h under nitrogen gas flow and kept at 1100° C. for 1 hour. After cooling to room temperature, taking out from the firing furnace, disintegrating with a rotary cutter mill, and sieving with a sieve with an opening of 45 ⁇ m, the bottom of the sieve is carbon black attached to a composite containing silicon-containing particles and carbonaceous material, carbon black attachment Obtained as a composite (A1).
  • a polyacrylate was mixed so that the binder would be 3% by mass, and the Cu foil current collector having a thickness of 10 ⁇ m was coated on one side to prepare a negative electrode sheet having a thickness of about 60 ⁇ m. ..
  • the negative electrode sheet was punched out to a diameter of 15 mm in a polypropylene cell with a screw-in lid (inner diameter of about 18 mm). This and a lithium metal foil punched out to 16 mm ⁇ were sandwiched between separators (polypropylene microporous film (Celguard 2400)) and laminated, and an electrolytic solution was added to obtain a test cell.
  • the electrolytic solution was prepared by mixing 5% by mass of fluoroethylene carbonate (FEC) in a solvent in which ethylene carbonate, ethylmethyl carbonate and diethyl carbonate were mixed in a volume ratio of 3:5:2, and further, electrolyte LiPF 6 was added thereto. Is a solution obtained by dissolving the above to a concentration of 1 mol/L. Using this counter electrode lithium half cell, the initial discharge capacity and the initial efficiency were measured by the methods described above.
  • FEC fluoroethylene carbonate
  • This powder coke 1 was filled in a graphite crucible and heat-treated in an Acheson furnace for 1 week so that the maximum temperature reached was about 3300° C. to obtain scaly artificial graphite particles (B1).
  • the scale-like artificial graphite particles (B1) thus obtained had D50 of 6.4 ⁇ m, BET specific surface area of 6.1 m 2 /g, d002 of 0.3357 nm, Lc of 104 nm, R value of 0.15, and orientation.
  • the index was 0.28.
  • the initial discharge capacity and the initial Coulombic efficiency of the artificial graphite particles (B1) were measured by the same method as the composite (A1). The initial discharge capacity was 355 mAh/g and the initial Coulombic efficiency was 93%.
  • ⁇ Negative electrode>> In a glove box in an argon gas atmosphere, 25 parts by mass of the composite (A1) and 25 parts by mass of the artificial graphite particles (B1), 45 parts by mass of the solid electrolyte (Li 3 PS 4 , D50:8 ⁇ m), and , 3 parts by mass of Denka Black (HS-100) as a conductive additive and 2 parts by mass of "VGCF-H" manufactured by Showa Denko KK were mixed, and further milled at 100 rpm for 1 hour using a planetary ball mill. It homogenized by processing and the negative electrode composite material was obtained. Next, the obtained negative electrode mixture was press-molded at 400 MPa with a uniaxial press molding machine using a polyethylene die having an inner diameter of 10 mm ⁇ and a SUS punch to obtain a negative electrode used in a battery evaluation test.
  • HS-100 Denka Black
  • the first charge was 0.35 mA (0.01 C) constant current charge up to 4.2 V, followed by constant voltage charge at a constant voltage of 4.2 V for 40 hours. After that, constant current discharge was performed at 0.35 mA (0.01 C) until the voltage became 2.75 V.
  • the capacity at the first charge/discharge was defined as the discharge capacity.
  • the initial discharge capacity/initial charge capacity*100 was defined as the initial Coulombic efficiency.
  • the initial discharge capacity measured at 25°C was taken as 100%, and the discharge capacity after 50 cycles was taken as the cycle characteristic (%).
  • charging was performed with constant current of 0.35 mA (0.01 C) until it reached 4.2 V, and then with constant voltage of 4.2 V until constant current was reduced to 0.005 C. Charged. Further, the discharge was performed by a constant current discharge of 0.35 mA (0.01 C) until 2.75 V was reached.
  • Example 2 A composite (A2) containing the silicon-containing particles (1) and the carbonaceous material was produced in the same manner as in Example 1 except that carbon black was not added. With respect to the obtained composite (A2), the initial discharge capacity and the initial Coulombic efficiency of the counter lithium half cell were measured in the same manner as in Example 1.
  • Example 3 A mixture of 1% by mass of petroleum pitch with a V-type mixer was mixed with the carbon black-adhered composite material (A1) produced in the example, and the mixture was put into a firing furnace. Under nitrogen gas flow, 150°C/h up to 1100°C. The temperature was raised and kept at 1100° C. for 1 hour. The mixture was cooled to room temperature, taken out from the firing furnace, and sieved with a sieve having an opening of 45 ⁇ m to obtain a bottom of the sieve as a composite (A3) in which the carbon black-adhered composite (A1) was coated with carbon. The surface of this composite (A3) was a carbonaceous material layer containing no silicon-containing particles. With respect to the obtained composite (A3), the initial discharge capacity and the initial Coulombic efficiency of the counter lithium half cell were measured by the same method as in Example 1.
  • Table 2 shows the physical properties of the composites (A1) to (A5), and the measurement results of the initial discharge capacity and the initial cloning efficiency using a counter electrode lithium half cell.
  • Table 3 shows the evaluation results of the all-solid-state lithium ion batteries of Examples 1 to 5 and Comparative Examples 1 to 4.

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Abstract

La présente invention aborde le problème de la fourniture d'un mélange d'électrode négative de batterie lithium-ion tout solide qui permet d'obtenir une batterie au lithium-ion tout solide ayant une capacité élevée, une efficacité coulombique élevée et des caractéristiques de cycle élevée. Ce mélange d'électrode négative de batterie lithium-ion tout solide est caractérisé en ce qu'il contient : un matériau d'électrode négative qui contient un complexe (A) comprenant des particules contenant du silicium et un matériau carboné, et au moins un composant (B) choisi parmi les matériaux carbonés et le graphite ; et un électrolyte solide. Cette batterie au lithium-ion tout solide est caractérisée en ce qu'elle contient une couche d'électrolyte solide, une électrode négative et une électrode positive, l'électrode négative étant formée à l'aide dudit mélange d'électrode négative.
PCT/JP2019/049107 2018-12-20 2019-12-16 Mélange d'électrode négative de batterie au lithium-ion tout solide et batterie au lithium-ion tout solide WO2020129879A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023007939A1 (fr) 2021-07-28 2023-02-02 パナソニックＩｐマネジメント株式会社 Matériau d'électrode négative, électrode négative, batterie et son procédé de production
WO2023073089A1 (fr) 2021-10-29 2023-05-04 Umicore Poudre destinée à être utilisée dans l'électrode négative d'une batterie, procédé de préparation d'une telle poudre et batterie comprenant une telle poudre

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JP2006049266A (ja) * 2004-07-09 2006-02-16 Samsung Sdi Co Ltd リチウム二次電池
JP2014187007A (ja) * 2013-02-21 2014-10-02 Ｃｏｎｎｅｘｘ Ｓｙｓｔｅｍｓ株式会社 リチウム二次電池用複合活物質およびその製造方法
WO2015159935A1 (fr) * 2014-04-16 2015-10-22 昭和電工株式会社 Matériau d'électrode négative pour batterie au lithium-ion, et son utilisation
JP2017054720A (ja) * 2015-09-10 2017-03-16 トヨタ自動車株式会社 全固体電池用負極
JP2018048070A (ja) * 2016-09-19 2018-03-29 三星電子株式会社Samsung Electronics Co., Ltd. 多孔性シリコン複合体クラスタ、それを利用した炭素複合体、並びにそれを含んだ、電極、リチウム電池、電界放出素子、バイオセンサ、半導体素子及び熱電素子
WO2018110386A1 (fr) * 2016-12-15 2018-06-21 昭和電工株式会社 Composite granulaire, électrode négative pour batterie secondaire au lithium-ion et procédé de fabrication de celle-ci

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Publication number Priority date Publication date Assignee Title
JP2006049266A (ja) * 2004-07-09 2006-02-16 Samsung Sdi Co Ltd リチウム二次電池
JP2014187007A (ja) * 2013-02-21 2014-10-02 Ｃｏｎｎｅｘｘ Ｓｙｓｔｅｍｓ株式会社 リチウム二次電池用複合活物質およびその製造方法
WO2015159935A1 (fr) * 2014-04-16 2015-10-22 昭和電工株式会社 Matériau d'électrode négative pour batterie au lithium-ion, et son utilisation
JP2017054720A (ja) * 2015-09-10 2017-03-16 トヨタ自動車株式会社 全固体電池用負極
JP2018048070A (ja) * 2016-09-19 2018-03-29 三星電子株式会社Samsung Electronics Co., Ltd. 多孔性シリコン複合体クラスタ、それを利用した炭素複合体、並びにそれを含んだ、電極、リチウム電池、電界放出素子、バイオセンサ、半導体素子及び熱電素子
WO2018110386A1 (fr) * 2016-12-15 2018-06-21 昭和電工株式会社 Composite granulaire, électrode négative pour batterie secondaire au lithium-ion et procédé de fabrication de celle-ci

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023007939A1 (fr) 2021-07-28 2023-02-02 パナソニックＩｐマネジメント株式会社 Matériau d'électrode négative, électrode négative, batterie et son procédé de production
WO2023073089A1 (fr) 2021-10-29 2023-05-04 Umicore Poudre destinée à être utilisée dans l'électrode négative d'une batterie, procédé de préparation d'une telle poudre et batterie comprenant une telle poudre

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