WO2023053631A1 - 非水電解質二次電池用負極活物質及び非水電解質二次電池 - Google Patents

非水電解質二次電池用負極活物質及び非水電解質二次電池 Download PDF

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WO2023053631A1
WO2023053631A1 PCT/JP2022/025674 JP2022025674W WO2023053631A1 WO 2023053631 A1 WO2023053631 A1 WO 2023053631A1 JP 2022025674 W JP2022025674 W JP 2022025674W WO 2023053631 A1 WO2023053631 A1 WO 2023053631A1
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silicate
negative electrode
electrolyte secondary
secondary battery
particles
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French (fr)
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公 小泉
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Sanyo Electric Co Ltd
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Sanyo Electric Co Ltd
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Priority to US18/694,550 priority Critical patent/US20250132311A1/en
Priority to CN202280062146.1A priority patent/CN117981112A/zh
Priority to JP2023550377A priority patent/JPWO2023053631A1/ja
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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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/20—Silicates
    • C01B33/32—Alkali metal silicates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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 disclosure relates to negative electrode active materials for non-aqueous electrolyte secondary batteries and non-aqueous electrolyte secondary batteries.
  • non-aqueous electrolyte secondary batteries have high voltage and high energy density, so they are expected to be used as power sources for small consumer applications, power storage devices, and electric vehicles.
  • the use of materials containing silicon that alloys with lithium is expected as a negative electrode active material with a high theoretical capacity density.
  • Patent Documents 1 and 2 disclose negative electrode active materials for non-aqueous electrolyte secondary batteries containing composite particles having silicon particles and a carbon phase covering the surface of the silicon particles.
  • Patent Document 3 discloses a negative electrode active material for a non-aqueous electrolyte secondary battery containing composite particles having a graphite base material and a nanosilicon material deposited inside the graphite base material. .
  • Patent Document 4 discloses a negative electrode active material for non-aqueous electrolyte secondary batteries containing composite particles having a lithium silicate phase and silicon particles dispersed in the lithium silicate phase.
  • Patent Document 5 discloses a negative electrode active material for a non-aqueous electrolyte secondary battery containing composite particles having a structure in which scale-like silicon particles are dispersed in a carbon material, and graphite-based particles.
  • an object of the present disclosure is to suppress deterioration in charge-discharge cycle characteristics of a non-aqueous electrolyte secondary battery using a negative electrode active material containing silicon particles.
  • a negative electrode active material for a non-aqueous electrolyte secondary battery which is one aspect of the present disclosure, includes a silicate-containing composite having a carbon phase and a plurality of Si-containing silicate particles dispersed in the carbon phase, wherein the Si-containing silicate particles has a silicate phase and a plurality of silicon particles dispersed in the silicate phase, and the ratio (B /A) is 15 or more and 120 or less.
  • a non-aqueous electrolyte secondary battery includes a negative electrode having a negative electrode mixture layer containing the negative electrode active material for a non-aqueous electrolyte secondary battery, a positive electrode, and a non-aqueous electrolyte.
  • FIG. 1 is a schematic cross-sectional view of a silicate-containing composite that is an example of an embodiment
  • FIG. 1 is a schematic cross-sectional view of Si-containing silicate particles constituting a silicate-containing composite.
  • a negative electrode active material for a non-aqueous electrolyte secondary battery which is one aspect of the present disclosure, includes a silicate-containing composite having a carbon phase and a plurality of Si-containing silicate particles dispersed in the carbon phase, wherein the Si-containing silicate particles has a silicate phase and a plurality of silicon particles dispersed in the silicate phase, and the ratio (B /A) is 15 or more and 120 or less.
  • the ratio (B /A) is 15 or more and 120 or less.
  • the above-mentioned particle cracking is further suppressed, and furthermore, the negative electrode of the negative electrode active material caused by the above-mentioned particle cracking. Since electrical isolation from the battery is suppressed, deterioration of charge-discharge cycle characteristics is suppressed.
  • a non-aqueous electrolyte secondary battery which is an example of an embodiment, includes a negative electrode, a positive electrode, and a non-aqueous electrolyte.
  • a separator is preferably provided between the positive electrode and the negative electrode.
  • An example of the structure of the non-aqueous electrolyte secondary battery includes a structure in which an electrode body in which a positive electrode and a negative electrode are wound with a separator interposed therebetween, and a non-aqueous electrolyte are accommodated in an outer package.
  • another form of electrode body such as a stacked electrode body in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween may be applied.
  • the non-aqueous electrolyte secondary battery may be of any shape such as cylindrical, square, coin, button, and laminate.
  • the positive electrode is preferably composed of, for example, a positive electrode current collector made of metal foil or the like, and a positive electrode mixture layer formed on the current collector.
  • a positive electrode current collector a foil of a metal such as aluminum that is stable in the positive electrode potential range, a film having the metal on the surface layer, or the like can be used.
  • the positive electrode mixture layer preferably contains a conductive material and a binder in addition to the positive electrode active material.
  • Examples of positive electrode active materials include lithium transition metal oxides containing transition metal elements such as Co, Mn, and Ni.
  • Lithium transition metal oxides include, for example, Li x CoO 2 , Li x NiO 2 , Li x MnO 2 , Li x Co y Ni 1-y O 2 , Li x Co y M 1-y O z , Li x Ni 1- yMyOz , LixMn2O4, LixMn2-yMyO4, LiMPO4 , Li2MPO4F ( M ; Na , Mg , Sc, Y , Mn, Fe, Co, Ni , Cu, Zn, Al, Cr, Pb, Sb, and B, 0 ⁇ x ⁇ 1.2, 0 ⁇ y ⁇ 0.9, 2.0 ⁇ z ⁇ 2.3). These may be used individually by 1 type, and may be used in mixture of multiple types.
  • Examples of conductive materials include carbon materials such as carbon black, acetylene black, ketjen black, and graphite. These may be used alone or in combination of two or more.
  • fluorine-based resins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyimide-based resins, acrylic-based resins, polyolefin-based resins, carboxymethylcellulose (CMC) or Salts thereof (CMC-Na, CMC-K, CMC- NH4 , etc., may also be partially neutralized salts), styrene-butadiene rubber (SBR), polyacrylic acid (PAA) or salts thereof (PAA -Na, PAA-K, and partially neutralized salts), polyvinyl alcohol (PVA), polyethylene oxide (PEO), and the like can be used. These may be used alone or in combination of two or more.
  • PTFE polytetrafluoroethylene
  • PVdF polyvinylidene fluoride
  • PAN polyacrylonitrile
  • polyimide-based resins acrylic-based resins
  • the negative electrode is preferably composed of, for example, a negative electrode current collector made of metal foil or the like, and a negative electrode mixture layer formed on the current collector.
  • a negative electrode current collector a foil of a metal such as copper that is stable in the potential range of the negative electrode, a film having the metal on the surface layer, or the like can be used.
  • the negative electrode mixture layer contains a negative electrode active material.
  • the negative electrode active material contains a silicate-containing composite, which will be described later.
  • the negative electrode mixture layer preferably contains a binder in addition to the negative electrode active material.
  • a binder fluorine-based resin, PAN, polyimide-based resin, acrylic-based resin, polyolefin-based resin, CMC or a salt thereof (CMC-Na, CMC-K, CMC- NH4 , etc., or It may be a partially neutralized salt), styrene-butadiene rubber (SBR), polyacrylic acid (PAA) or a salt thereof (PAA-Na, PAA-K, etc., or a partially neutralized salt may be used), polyvinyl alcohol (PVA), polyethylene oxide (PEO), and the like can be used.
  • FIG. 1 shows a schematic cross-sectional view of a silicate-containing composite that is an example of an embodiment
  • FIG. 2 shows a schematic cross-sectional view of Si-containing silicate particles constituting the silicate-containing composite.
  • a silicate-containing composite 10 has a carbon phase 12 and a plurality of Si-containing silicate particles 14 dispersed in the carbon phase 12 .
  • a silicate-containing composite 10 has a sea-island structure in which a plurality of Si-containing silicate particles 14 are dispersed in a matrix of a carbon phase 12 .
  • the carbon phase 12 is preferably composed of amorphous carbon.
  • the carbon phase 12 may contain crystalline carbon such as graphite, but the content of the crystalline carbon is preferably 5% by mass or less, more preferably 1% by mass or less, relative to the total amount of the carbon phase 12. preferable.
  • the content of the carbon phase 12 is preferably 10% by mass or more and 45% by mass or less with respect to the total amount of the silicate-containing composite 10.
  • the content of the carbon phase 12 satisfies the above range, compared with the case of less than 10% by mass, for example, the conductivity of the Si-containing silicate particles 14 is sufficiently ensured, so that the charge-discharge cycle characteristics are more deteriorated. may be suppressed.
  • the content of the carbon phase 12 satisfies the above range, compared to the case of exceeding 45% by mass, for example, the packing density of the Si-containing silicate particles 14 is improved, and the capacity of the non-aqueous electrolyte secondary battery is increased. may be attempted.
  • the carbon phase 12 is obtained from an organic compound (carbon precursor) that can be converted to carbonaceous by heat treatment.
  • Carbon precursors include, for example, crude oil pitch, coal tar pitch, asphalt decomposition pitch, pitch generated by thermally decomposing organic compounds such as polyvinyl chloride, naphthalene, etc., which are polymerized in the presence of a superacid.
  • a synthetic pitch etc. are mentioned. Synthetic polymers such as phenol resin, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate and polyvinyl butyral, and natural polymers such as starch and cellulose may also be used.
  • the Si-containing silicate particles 14 have a silicate phase 16 and a plurality of silicon particles 18 dispersed in the silicate phase 16 . It is desirable that a plurality of silicon particles 18 are dispersed substantially uniformly within the silicate phase 16 .
  • the Si-containing silicate particles 14 have, for example, a sea-island structure in which a plurality of fine silicon particles 18 are dispersed in the matrix of the silicate phase 16 .
  • the Si-containing silicate particles 14 may contain a third component in addition to the silicate phase 16 and silicon particles 18 .
  • silicate phase 16 may include crystalline or amorphous SiO 2 in addition to lithium silicate.
  • the SiO 2 content in the Si-containing silicate particles 14 measured by Si-NMR is, for example, preferably 30% by mass or less, more preferably 7% by mass or less.
  • the silicon particles 18 can occlude more lithium ions than carbon materials such as graphite, their application to the negative electrode active material contributes to increasing the capacity of the battery.
  • the content of the silicon particles 18 (simple Si) in the Si-containing silicate particles 14 measured by Si-NMR is, for example, preferably 20% by mass to 95% by mass, more preferably 35% by mass to 75% by mass, from the viewpoint of increasing the capacity. % by mass is more preferred.
  • the silicate phase 16 has, for example, the formula: Li 2 Si 2 O 5. (x-2)SiO 2 , Li 2 O.2SiO 2. (x-2) SiO 2 , or Li 2 O.xSiO 2 (2 ⁇ x ⁇ 18).
  • Such lithium silicate is desirably contained in the silicate phase 16 in an amount of 90% by mass or more. It is desirable that the silicate phase 16 contain almost no Li 4 SiO 4 and Li 2 SiO 3 which tend to elute alkaline components.
  • the silicate phase 16 includes , in addition to the phase of Li2Si2O5 , for example Li2Si3O7 , Li2Si4O9 , Li2Si5O11 , Li2Si6O13 , Li 2 Si 7 O 15 , Li 2 Si 8 O 17 , Li 2 Si 9 O 19 , Li 2 Si 10 O 21 , and other phases are delocalized, and the above composition is the average composition of the whole including crystalline and amorphous. show.
  • the phase of Li 2 Si 2 O 5 is preferable to use as the main component (the component with the largest mass) . It is preferably more than 15% by mass, more preferably 40% by mass or more. Desirable Si-NMR measurement conditions are shown below.
  • Measurement device Solid-state nuclear magnetic resonance spectrometer (INOVA-400) manufactured by Varian Probe: Varian 7mm CPMAS-2 MAS: 4.2kHz MAS speed: 4kHz Pulse: DD (45° pulse + signal acquisition time 1H decouple) Repeat time: 1200sec Observation width: 100kHz Observation center: Around -100 ppm Signal capture time: 0.05 sec Cumulative count: 560 Sample amount: 207.6 mg
  • composition of the silicate phase 16 can be analyzed as follows.
  • the mass of the sample of the silicate-containing composite 10 is measured. After that, the contents of carbon, lithium and oxygen contained in the sample are calculated as follows. Next, the carbon content is subtracted from the mass of the sample to calculate the lithium and oxygen content in the remaining amount, and the x value is obtained from the molar ratio of lithium (Li) and oxygen (O).
  • the carbon content is measured using a carbon/sulfur analyzer (for example, EMIA-520 model manufactured by Horiba, Ltd.).
  • a sample is measured on a magnetic board, a combustion improver is added, the board is inserted into a combustion furnace (carrier gas: oxygen) heated to 1350° C., and the amount of carbon dioxide gas generated during combustion is detected by infrared absorption.
  • a calibration curve is prepared, for example, in the Bureau of Analyzed Sample. Ltd. carbon steel (carbon content 0.49%) is used, and the carbon content of the sample is calculated (high-frequency induction heating furnace combustion-infrared absorption method).
  • the oxygen content is measured using an oxygen/nitrogen/hydrogen analyzer (for example, Model EGMA-830 manufactured by Horiba, Ltd.).
  • An oxygen/nitrogen/hydrogen analyzer for example, Model EGMA-830 manufactured by Horiba, Ltd.
  • a sample is placed in a Ni capsule, which is put into a carbon crucible heated with a power of 5.75 kW together with Sn pellets and Ni pellets as fluxes, and carbon monoxide gas released is detected.
  • a calibration curve is prepared using a standard sample Y 2 O 3 , and the oxygen content of the sample is calculated (inert gas fusion-nondispersive infrared absorption method).
  • Lithium content was determined by dissolving all the sample in hot hydrofluoric/nitric acid (mixed acid of hot hydrofluoric acid and nitric acid), removing carbon from the dissolution residue by filtration, and then subjecting the resulting filtrate to inductively coupled plasma emission spectroscopy ( Analyze by ICP-AES) to determine the lithium content.
  • a calibration curve is prepared using a commercially available lithium standard solution, and the lithium content of the sample is calculated.
  • the ratio (B/A) of the average particle size (B) of the silicate-containing composite 10 to the average particle size (A) of the Si-containing silicate particles 14 is 15 or more and 120 or less, preferably 20. 120 or less.
  • B/A satisfies the above range
  • the Si-containing silicate particles 14 can be dispersed in the carbon phase 12 without being exposed from the surface of the carbon phase 12. Therefore, for example, negative electrode activity caused by particle cracking can be prevented. Electrical isolation of the substance from the negative electrode is suppressed, and deterioration of charge-discharge cycle characteristics of the non-aqueous electrolyte secondary battery is suppressed.
  • the average particle size of the silicate-containing composite 10 is preferably 4 ⁇ m or more and 15 ⁇ m or less, more preferably 4 ⁇ m or more and 8 ⁇ m or less.
  • the Si-containing silicate particles 14 are not exposed from the surface of the carbon phase 12, and are inside the carbon phase 12, compared to the case where the above range is not satisfied.
  • the electrical isolation of the negative electrode active material from the negative electrode caused by particle cracking is suppressed, and the deterioration of the charge-discharge cycle characteristics of the non-aqueous electrolyte secondary battery may be further suppressed. be.
  • the average particle size of the silicate-containing composite 10 means the particle size (volume average particle size) at which the volume integrated value is 50% in the particle size distribution measured by the laser diffraction scattering method.
  • “LA-750" manufactured by HORIBA, Ltd. can be used as the measuring device.
  • the average particle diameter of the Si-containing silicate particles 14 is preferably 1 ⁇ m or less, more preferably 200 nm or less.
  • the Si-containing silicate particles 14 are not exposed from the surface of the carbon phase 12, and are inside the carbon phase 12, compared to the case where the above range is not satisfied.
  • the electrical isolation of the negative electrode active material from the negative electrode caused by particle cracking is suppressed, and the deterioration of the charge-discharge cycle characteristics of the non-aqueous electrolyte secondary battery may be further suppressed.
  • the average particle diameter of the Si-containing silicate particles 14 means the volume-average particle diameter as in the case of the silicate-containing composite 10 .
  • the average particle diameter of the silicon particles 18 is, for example, 500 nm or less, preferably 200 nm or less, and more preferably 50 nm or less before the first charge.
  • the average particle diameter of the silicon particles 18 satisfies the above range, the volume change during charging and discharging is reduced compared to the case where the above range is not satisfied, particle cracking is suppressed, and the silicon particles 18 form the silicate phase 16. Since it becomes easy to disperse in the silicate phase 16 without being exposed from the surface, for example, a side reaction between the non-aqueous electrolyte and the silicon particles 18 can be suppressed.
  • the average particle diameter of the silicon particles 18 is measured by observing the cross section of the silicate-containing composite 10 using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). It is obtained by converting the individual areas of the particles 18 into equivalent circular diameters and averaging them.
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • the silicate-containing composite 10 may be used alone, or may be used in combination with other active materials.
  • the content of the silicate-containing composite 10 is, for example, 1% by mass or more and 50% by mass with respect to the total amount of the negative electrode mixture layer in order to increase the capacity of the battery while suppressing deterioration in charge-discharge cycle characteristics. It is preferably 10% by mass or more and 45% by mass or less.
  • a carbon material such as graphite is preferable.
  • the mass ratio of the silicate-containing composite 10 and the carbon material is preferably 1:99 to 30:70 from the viewpoints of increasing capacity and suppressing deterioration of charge-discharge cycle characteristics.
  • silicate powder For example, silicon dioxide and a lithium compound are mixed at a predetermined mass ratio, and the mixture is heated in the air at 400° C. to 1200° C. to obtain the formula: Li 2 Si 2 O 5. (x ⁇ 2) A silicate powder represented by SiO 2 , Li 2 O.2SiO 2 .(x ⁇ 2)SiO 2 , or Li 2 O.xSiO 2 (2 ⁇ x ⁇ 18) is obtained. Moreover, it is desirable to pulverize the obtained silicate powder to a predetermined particle size.
  • silicate powder and silicon powder are mixed at a predetermined mass ratio, and the mixture is stirred in an inert atmosphere using a pulverizing device such as a planetary ball mill to combine the silicate powder and silicon powder ( compounding treatment) to obtain Si-containing silicate particles.
  • a pulverizing device such as a planetary ball mill to combine the silicate powder and silicon powder ( compounding treatment) to obtain Si-containing silicate particles.
  • the time for the compounding treatment may be, for example, 3 hours to 15 hours.
  • Si-containing silicate particles are pulverized and classified by an air classifier.
  • Si-containing silicate particles and carbon precursors e.g., pitches, resins, thermally decomposable carbon gas, etc.
  • the stirring time may be, for example, 30 minutes to 3 hours.
  • the stirred mixture is heated, for example, at 450° C. to 1000° C. in an inert atmosphere and fired to obtain a silicate-containing composite.
  • the mixture may be fired while applying pressure to the mixture by hot pressing or the like. Since silicate is stable at 450° C. to 1000° C. and hardly reacts with silicon, even if a decrease in capacity occurs, it is slight.
  • the carbon precursor is not crystallized at 450° C. to 1000° C. and is in an amorphous state.
  • the non-aqueous electrolyte includes a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent.
  • the lithium salt concentration in the nonaqueous electrolyte is, for example, 0.5 to 2 mol/L.
  • the non-aqueous electrolyte may contain known additives.
  • non-aqueous solvent for example, cyclic carbonate, chain carbonate, cyclic carboxylate, and the like are used.
  • Cyclic carbonates include propylene carbonate (PC) and ethylene carbonate (EC).
  • Chain carbonates include diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC) and the like.
  • Cyclic carboxylic acid esters include ⁇ -butyrolactone (GBL) and ⁇ -valerolactone (GVL).
  • the non-aqueous solvent may be used singly or in combination of two or more.
  • lithium salts examples include lithium salts of chlorine-containing acids ( LiClO4 , LiAlCl4 , LiB10Cl10 , etc.), lithium salts of fluorine- containing acids ( LiPF6 , LiBF4 , LiSbF6 , LiAsF6 , LiCF3SO3 , LiCF3CO2 , etc. ), lithium salts of fluorine - containing acid imides (LiN( CF3SO2 ) 2 , LiN( CF3SO2 ) ( C4F9SO2 ) , LiN( C2F5SO2 ) 2, etc.), lithium halides (LiCl, LiBr, LiI, etc.) and the like can be used. Lithium salts may be used singly or in combination of two or more.
  • a porous sheet having ion permeability and insulation is used.
  • porous sheets include microporous thin films, woven fabrics, and non-woven fabrics.
  • Suitable materials for the separator include olefin resins such as polyethylene and polypropylene, and cellulose.
  • the separator may be a laminate having a cellulose fiber layer and a thermoplastic resin fiber layer such as an olefin resin.
  • Lithium silicate (Li 2 O.2.1SiO 2 ) with an average particle size of 10 ⁇ m and raw material silicon (3N, average particle size of 10 ⁇ m) were mixed at a mass ratio of 50:50, and the mixture was subjected to a planetary ball mill (manufactured by Fritsch, P-5) pot (made of SUS, volume: 500 mL) is filled, 24 SUS balls (20 mm in diameter) are placed in the pot, the lid is closed, and the mixture is compounded for 50 hours at 200 rpm in an inert atmosphere. treated to obtain Si-containing silicate particles.
  • the Si-containing silicate particles obtained by the compounding treatment were pulverized and classified by an air classifier to obtain Si-containing silicate particles with an average particle size of 0.2 ⁇ m.
  • a predetermined amount of Si-containing silicate particles having an average particle size of 0.2 ⁇ m is filled in a pot (made of SUS, volume: 500 mL) of a planetary ball mill (P-5, manufactured by Fritsch), and the silicate-containing composite after firing is filled.
  • a pot made of SUS, volume: 500 mL
  • P-5 planetary ball mill
  • the silicate-containing composite after firing is filled.
  • a silicate-containing composite was obtained by sintering the mixture obtained by the above stirring under conditions of 800°C for 4 hours in an inert atmosphere.
  • the obtained silicate-containing composite was pulverized and classified by an air classifier. Thereafter, a sieve was used to obtain a silicate-containing composite having an average particle size of 12 ⁇ m.
  • the crystallite size of the silicon particles calculated by Scherrer's formula from the diffraction peak attributed to the Si (111) plane in the XRD analysis of the silicate-containing composite was 15 nm.
  • Si /Li ratio was 1.05, and the content of Li 2 Si 2 O 5 measured by Si-NMR was 48% by mass.
  • the silicate-containing composite had a plurality of Si-containing silicate particles dispersed in the carbon phase, and that the Si-containing silicate particles were dispersed in the silicate phase. It was confirmed that a plurality of silicon particles were dispersed.
  • the particle morphology of the silicate-containing composite observed in the SEM photograph was the same in Experimental Examples 2 to 11 below.
  • Solid content of slurry (%) (Solid components in negative electrode mixture slurry (graphite, silicate-containing composite, etc.) ⁇ (negative electrode mixture slurry mass) ⁇ 100
  • the negative electrode mixture slurry was applied to both sides of the copper foil by a doctor blade method, the coating film was dried, and then rolled to prepare a negative electrode having negative electrode mixture layers formed on both sides of the copper foil. .
  • a lithium transition metal oxide represented by LiNi 0.88 Co 0.09 Al 0.03 O 2 , acetylene black, and polyvinylidene fluoride were mixed at a mass ratio of 95:2.5:2.5. , and N-methyl-2-pyrrolidone (NMP) were added, and then stirred using a mixer (TK Hibismix manufactured by Primix) to prepare a positive electrode mixture slurry.
  • NMP N-methyl-2-pyrrolidone
  • the positive electrode mixture slurry was applied to the surface of the aluminum foil, the coating film was dried, and then rolled to form a positive electrode mixture layer having a density of 3.6 g/cm 3 on both sides of the aluminum foil.
  • a positive electrode was produced.
  • a nonaqueous electrolytic solution was prepared by adding LiPF6 to a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) at a volume ratio of 3:7 to a concentration of 1.0 mol/L. bottom.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • An electrode body was produced by attaching a tab to each electrode, arranging the positive electrode and the negative electrode with a separator interposed therebetween, and spirally winding them. This electrode body is placed in a battery casing made of an aluminum laminate film, vacuum dried at 105 ° C. for 2 hours, a non-aqueous electrolyte is injected into the battery casing, the battery casing is sealed, and the battery is completed. made.
  • Example 2 A battery was fabricated in the same manner as in Experimental Example 1, except that the pot was filled with coal tar pitch so that the mass ratio of the carbon phase in the silicate-containing composite was 10%.
  • Example 3 A battery was fabricated in the same manner as in Experimental Example 1, except that the pot was filled with coal tar pitch so that the mass ratio of the carbon phase in the silicate-containing composite was 45%.
  • Example 4 A battery was fabricated in the same manner as in Experimental Example 1, except that the average particle size of the Si-containing silicate particles obtained by the compounding treatment was adjusted to 1 ⁇ m by pulverization and classification using an air classifier.
  • Example 5 A battery was fabricated in the same manner as in Experimental Example 1, except that the average particle size of the Si-containing silicate particles obtained by the compounding treatment was adjusted to 6 ⁇ m by pulverization and classification using an air classifier.
  • Example 6 A battery was produced in the same manner as in Experimental Example 1, except that the average particle size of the silicate-containing composite was adjusted to 15 ⁇ m by pulverization, classification, and sieving using an air classifier.
  • Example 7 A battery was produced in the same manner as in Experimental Example 1, except that the average particle size of the silicate-containing composite was adjusted to 8 ⁇ m by pulverization, classification, and sieving using an air classifier.
  • Example 8 A battery was produced in the same manner as in Experimental Example 1, except that the average particle size of the silicate-containing composite was adjusted to 4 ⁇ m by pulverization, classification, and sieving using an air classifier.
  • Example 9 A battery was produced in the same manner as in Experimental Example 1, except that the coal tar pitch was replaced with a phenolic resin.
  • Example 10 A battery was fabricated in the same manner as in Experimental Example 1, except that the average particle diameter of the Si-containing silicate particles obtained by the compounding treatment was adjusted to 0.1 ⁇ m by pulverization and classification using an air classifier.
  • Example 11 The average particle diameter of the Si-containing silicate particles obtained by the composite treatment was adjusted to an average particle diameter of 0.1 ⁇ m by pulverization and classification with an air classifier, and the average particle diameter of the silicate-containing composite was measured by the air classifier.
  • a battery was produced in the same manner as in Experimental Example 1, except that the average particle size was adjusted to 10 ⁇ m by pulverizing, classifying, and sieving.
  • Example 12 A battery was produced in the same manner as in Experimental Example 1, except that the Si-containing silicate particles obtained by the composite treatment were used as the negative electrode active material without producing a silicate-containing composite.
  • Lithium silicate (Li 2 O.2.1SiO 2 ) with an average particle size of 10 ⁇ m and raw material silicon (3N, average particle size of 10 ⁇ m) were mixed at a mass ratio of 50:50, and the mixture was subjected to a planetary ball mill (manufactured by Fritsch, P-5) pot (made of SUS, volume: 500 mL) is filled, 24 SUS balls (20 mm in diameter) are placed in the pot, the lid is closed, and the mixture is compounded for 50 hours at 200 rpm in an inert atmosphere. treated to obtain Si-containing silicate particles.
  • the Si-containing silicate particles obtained by the compounding treatment were pulverized and classified by an air classifier to obtain Si-containing silicate particles with an average particle size of 12 ⁇ m.
  • a predetermined amount of Si-containing silicate particles with an average particle size of 12 ⁇ m was filled in a pot (made of SUS, volume: 500 mL) of a planetary ball mill (manufactured by Fritsch, P-5). After filling the pot with coal tar pitch so that the mass ratio of is 4%, put 24 SUS balls (20 mm in diameter) in the pot and close the lid. Stirred for an hour.
  • a silicate-containing composite was obtained by sintering the mixture obtained by the above stirring under conditions of 800°C for 1 hour in an inert atmosphere. After that, a silicate-containing composite whose particle size distribution was adjusted using a sieve was obtained. The volume average particle size of the obtained silicate-containing composite was approximately the same as the average particle size of the Si-containing silicate particles.
  • the silicate-containing composite of Experimental Example 13 When the particle cross section of the silicate-containing composite of Experimental Example 13 was observed with an SEM photograph, the silicate-containing composite had a carbon film coated on the surface of the Si-containing silicate particles in which a plurality of silicon particles were dispersed in the silicate phase. It was confirmed that the particles were
  • Table 1 summarizes the results of the capacity retention rate based on the charge-discharge cycle test of each experimental example. Note that the higher the value of the capacity retention rate, the more suppressed the deterioration of the charge-discharge cycle characteristics.
  • silicate-containing composite 12 carbon phase
  • Si-containing silicate particles 16 silicate phase
  • 18 silicon particles 10 silicate-containing composite, 12 carbon phase, 14 Si-containing silicate particles, 16 silicate phase, 18 silicon particles.

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JPWO2023074099A1 (https=) * 2021-10-25 2023-05-04
TWI890996B (zh) * 2023-04-19 2025-07-21 國立臺灣科技大學 一種可調溶劑化特性的電解質溶劑、其製造方法與應用

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JP2007059213A (ja) * 2005-08-24 2007-03-08 Toshiba Corp 非水電解質電池および負極活物質
WO2015145521A1 (ja) * 2014-03-24 2015-10-01 株式会社 東芝 非水電解質電池用負極活物質、非水電解質二次電池用負極、非水電解質二次電池及び電池パック
WO2020129652A1 (ja) * 2018-12-21 2020-06-25 パナソニックＩｐマネジメント株式会社 二次電池用負極活物質および二次電池
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WO2015145521A1 (ja) * 2014-03-24 2015-10-01 株式会社 東芝 非水電解質電池用負極活物質、非水電解質二次電池用負極、非水電解質二次電池及び電池パック
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JPWO2023074099A1 (https=) * 2021-10-25 2023-05-04
JP7364125B2 (ja) 2021-10-25 2023-10-18 Dic株式会社 二次電池用複合活物質および二次電池
TWI890996B (zh) * 2023-04-19 2025-07-21 國立臺灣科技大學 一種可調溶劑化特性的電解質溶劑、其製造方法與應用

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