WO2020137909A1 - Matériau de graphite pour électrode négative de batterie secondaire au lithium-ion - Google Patents

Matériau de graphite pour électrode négative de batterie secondaire au lithium-ion Download PDF

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WO2020137909A1
WO2020137909A1 PCT/JP2019/050171 JP2019050171W WO2020137909A1 WO 2020137909 A1 WO2020137909 A1 WO 2020137909A1 JP 2019050171 W JP2019050171 W JP 2019050171W WO 2020137909 A1 WO2020137909 A1 WO 2020137909A1
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negative electrode
graphite material
less
ion secondary
secondary battery
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PCT/JP2019/050171
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Japanese (ja)
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武内　正隆
祐一 上條
安顕 脇坂
俊介 吉岡
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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
    • 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
    • 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

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  • the present invention relates to a graphite material for a negative electrode of a lithium ion secondary battery, and a lithium ion secondary battery and an all-solid-state lithium ion secondary battery using the graphite material as a negative electrode material.
  • lithium-ion secondary batteries have become the mainstream because of their large energy density and long cycle life. Since the functions of mobile devices are diversified and the power consumption is increased, it is required for lithium ion secondary batteries to further increase the energy density thereof and at the same time improve the charge/discharge cycle characteristics.
  • high-output and large-capacity secondary batteries for electric tools such as electric drills and hybrid vehicles.
  • lead secondary batteries, nickel-cadmium secondary batteries, and nickel-hydrogen secondary batteries have been mainly used in this field, but expectations for small, lightweight, high energy density lithium ion secondary batteries are high, and large currents are high.
  • a lithium ion secondary battery having excellent load characteristics (rate characteristics) is required.
  • BEV battery electric vehicles
  • HEV hybrid electric vehicles
  • long-term cycle characteristics for 10 years or more and rate characteristics for driving a high-power motor are mainly required characteristics
  • a high volumetric energy density is required to extend the cruising range, which is severe compared to mobile applications.
  • This lithium-ion secondary battery generally uses a metal oxide such as lithium cobalt oxide or lithium manganate or a composite oxide thereof as a positive electrode active material, a lithium salt as an electrolyte solution, and a graphite as a negative electrode active material. Carbonaceous materials are used. As graphite, there are natural graphite and artificial graphite.
  • Patent Document 1 proposes a method of coating artificial carbon on the surface of natural graphite processed into a spherical shape.
  • the material produced by this method can meet the high capacity, low current and medium cycle characteristics required for mobile applications, etc., it can meet the requirements for large current and long cycle characteristics of large batteries as described above. Very difficult to meet.
  • natural graphite has many metal impurities such as iron, which is problematic in terms of quality stability.
  • ⁇ As artificial graphite those obtained by graphitizing petroleum, coal pitch, coke, etc. can be obtained at relatively low cost.
  • the needle-shaped coke having good crystallinity becomes scaly and is easily oriented.
  • the method described in Patent Document 2 has been successful.
  • not only fine powder of artificial graphite raw material but also fine powder of natural graphite and the like can be used, and it has high capacity and excellent characteristics as the graphite for small lithium ion secondary batteries to date.
  • it is essential to improve productivity with an increase in the amount used, reduce manufacturing cost, control impurities, and improve cycle characteristics and storage characteristics.
  • the negative electrode material using so-called hard carbon or amorphous carbon described in Patent Document 3 has excellent characteristics with respect to a large current, and also has relatively good cycle characteristics.
  • the volume energy density is too low and the price is very expensive, so that it is used only for some special large batteries.
  • An object of the present invention is to provide a graphite material for a lithium-ion secondary battery negative electrode, which can be used to manufacture an electrode having both high cycle characteristics, high rate characteristics, and high energy density required for a large battery.
  • the present invention has the following configurations.
  • the average spacing d002 of (002) planes measured by X-ray diffraction is 0.3354 nm or more and 0.3370 nm or less,
  • the surface roughness calculated from the ratio of the BET surface area to the sphere-converted area calculated from the particle size distribution (BET surface area/sphere-converted area) is 6.0 to 14.0,
  • the ratio of the area of the optically anisotropic domain is 95.0% with respect to the total area of the optically anisotropic domain, the optically isotropic domain and the void of 100.0% measured by observing the cross section of the graphite material with a polarization microscope.
  • the integrated value when the areas of the optically anisotropic domains are integrated in order from the smallest one is the maximum domain area ( ⁇ m 2 ) when n% of the area ( ⁇ m 2 ) of all the optically anisotropic domains is reached.
  • a graphite material for a negative electrode of a lithium ion secondary battery that satisfies the following conditions (1) to (3) when Da(n) (where n represents a numerical value in the range of 0 to 100) is satisfied.
  • the ratio of the area of the void is 1.0% or less with respect to the total area of the optically anisotropic domain, the area of the optically isotropic domain and the area of the void of 100.0%. 1.
  • Db is the maximum domain area ( ⁇ m 2 ) when the total number of optically anisotropic domains arranged in ascending order of area reaches m% of the number of all optically anisotropic domains.
  • the 10% particle diameter (D10) in the volume-based particle diameter distribution measured by a laser diffraction method is 1.0 ⁇ m or more and 16.0 ⁇ m or less, and the 50% particle diameter (D50) is 6.0 ⁇ m or more and 30.0 ⁇ m.
  • the graphite material for a negative electrode of a lithium ion secondary battery according to any one of 1 to 6 above which has a circularity of 0.89 or more and 0.98 or less.
  • a negative electrode for a lithium ion secondary battery containing the negative electrode active material as described in 10 above.
  • a graphite material for a lithium-ion secondary battery which can be used to manufacture an electrode having both high cycle characteristics, high rate characteristics, and high energy density required by a large battery.
  • FIG. 1 is a schematic diagram showing an example of the configuration of an all-solid-state lithium-ion secondary battery in one embodiment of the present invention.
  • graphite material (I) A graphite material for a negative electrode of a lithium ion secondary battery (hereinafter, also referred to as “graphite material (I)”) in one embodiment of the present invention will be described in detail below.
  • the average interplanar spacing d002 of the (002) planes of the graphite material (I) measured by X-ray diffraction is 0.3354 nm or more.
  • 0.3354 nm is the lower limit value of d002 of the graphite crystal.
  • the d002 is preferably 0.3356 nm or more. When the d002 is 0.3356 nm or more, the graphite crystal structure is not overdeveloped, and the cycle characteristics are excellent.
  • d002 is 0.3370 nm or less, preferably 0.3365 nm or less, more preferably 0.3360 nm or less from the viewpoint that the discharge capacity becomes large and a battery satisfying the energy density required for a large battery can be obtained. is there.
  • the crystallite size Lc of the (002) diffraction line of the graphite material (I) measured by X-ray diffraction is preferably 80 nm from the viewpoint that the discharge capacity becomes large and a battery satisfying the energy density required for a large battery can be obtained. Or more, more preferably 90 nm or more, and further preferably 100 nm or more. Further, the Lc(002) is preferably 1000 nm or less, more preferably 500 nm or less, still more preferably 300 nm or less, from the viewpoint that the graphite crystal structure does not develop too much and the cycle characteristics are excellent.
  • the graphite crystal plane spacing d002 and the crystallite size Lc can be measured using a powder X-ray diffraction (XRD) method (see Iwashita et al., Carbon vol. 42 (2004), p. 701-714).
  • XRD powder X-ray diffraction
  • the surface roughness of a graphite material is determined by the ratio of the BET surface area to the sphere-converted area calculated from the particle size distribution (BET surface area/sphere-converted area) (Toshio Oshima et al., Journal of Powder Engineering). , Vol. 30, No. 7, (1993) 496-501).
  • the surface roughness of the graphite material (I) is 6.0 or more, preferably 7.0 or more, and more preferably 8.0 or more, from the viewpoint that resistance tends to decrease and rate characteristics tend to improve. Further, the surface roughness is 14.0 or less, preferably 13.0 or less, more preferably 12.0 or less from the viewpoint of suppressing side reactions with the electrolytic solution and excellent cycle characteristics.
  • the BET specific surface area can be determined using a specific surface area meter using a nitrogen gas adsorption method (for example, NOVA-1200 manufactured by Quantachrome).
  • a nitrogen gas adsorption method for example, NOVA-1200 manufactured by Quantachrome.
  • the sphere-converted area ( SD ) calculated from the particle size distribution can be calculated by the following formula based on the data of the particle size distribution obtained by using a laser diffraction type particle size distribution measuring device (for example, Mastersizer manufactured by Malvern Instruments Ltd.). it can.
  • a laser diffraction type particle size distribution measuring device for example, Mastersizer manufactured by Malvern Instruments Ltd.
  • Vi is the relative volume of the particle size category i (average diameter d i ), ⁇ is the particle density, and D is the particle size.
  • a graphite material is a domain that exhibits optical anisotropy (a domain in which crystals have developed and a graphite network plane is arranged.
  • an optically anisotropic domain a domain in which crystals have developed and a graphite network plane is arranged.
  • an optically isotropic domain a domain in which crystals are undeveloped or in which crystal disorder such as hard carbon is large.
  • an optically isotropic domain a domain in which crystals are undeveloped or in which crystal disorder such as hard carbon is large.
  • the domain means a unit region where optical tissues are continuous.
  • the measuring method is according to the method described in Examples.
  • the area of the optically anisotropic domain is 95.0% or more, preferably 96% with respect to the total area of the optically anisotropic domains, optically isotropic domains, and voids of 100.0%. It is 0.0% or more. Since the optically anisotropic domain contributes to insertion/desorption of lithium ions and the like, the energy density becomes large when the content is 95.0% or more. Further, the area of the optically anisotropic domain is 99.0% or less, preferably 98.0% or less, from the viewpoint that an optically isotropic domain can be sufficiently secured and cycle characteristics and rate characteristics are excellent.
  • the area of the optically isotropic domain is 100.0% of the total of the area of the optically anisotropic domain, the area of the optically isotropic domain, and the area of the voids, which is excellent in rate characteristics and cycle characteristics. Therefore, it is preferably 1.0% or more, and more preferably 1.5% or more.
  • the area of the optically isotropic domain is preferably 5.0% or less, and more preferably 4.0% or less, from the viewpoint that the optically anisotropic domain can be sufficiently secured and the energy density is excellent.
  • the area of the voids is preferably 1.0% or less, more preferably 0% with respect to the total of the area of the optically anisotropic domain, the area of the optically isotropic domain, and the area of the voids of 100.0%. It is 0.5% or less, and more preferably 0.3% or less. Since the voids do not directly contribute to charge and discharge, the energy density becomes high when the void content is 1.0% or less.
  • Da(10) is preferably 7 ⁇ m 2 or more, more preferably 8 ⁇ m 2 or more, and Da(10) is preferably 16 ⁇ m 2 or less, more preferably 12 ⁇ m 2 or less.
  • Da(50) is preferably 100 ⁇ m 2 or more, more preferably 150 ⁇ m 2 or more, and Da(50) is preferably 230 ⁇ m 2 or less, more preferably 210 ⁇ m 2 or less.
  • Da (90) is preferably 250 [mu] m 2 or more, more preferably 300 [mu] m 2 or more, also, Da (90) is preferably 450 [mu] m 2 or less, more preferably 420 [mu] m 2 or less.
  • Da(30) is preferably 10 ⁇ m 2 or more, more preferably 20 ⁇ m 2 or more, further preferably 30 ⁇ m 2 or more, and , Da(30) is preferably 90 ⁇ m 2 or less, more preferably 80 ⁇ m 2 or less, still more preferably 70 ⁇ m 2 or less.
  • Db(99.5)/Da(100) is more preferably 0.65 or less, still more preferably 0.55 or less.
  • Lmax/Lave In the optically anisotropic domain of the graphite material (I), the maximum value of the long side length is Lmax, and the 50% particle diameter (D50) in the volume-based particle diameter distribution of the graphite material (I) by the laser diffraction method.
  • Is Lave, Lmax/Lave is preferably 1.00 or less, and more preferably 0.95 or less.
  • Lmax/Lave is 1.00 or less, the optically anisotropic domains are not too large, and the orientation of the carbon network in each domain is not oriented in one direction but is oriented in any direction. The expansion and contraction of the crystallite at that time are dispersed, and as a result, the amount of deformation of the electrode becomes small.
  • the probability of losing electrical contact between particles is reduced even when charging and discharging are repeated, and cycle characteristics are improved.
  • the rate characteristic is also advantageous.
  • the measurement of Love can be performed using a laser diffraction type particle size distribution measuring instrument such as Malvern Mastersizer.
  • Cmin The orientation of the optically anisotropic domain can be confirmed from the change in domain interference color when the sample is rotated from 0 to 45 degrees with respect to the analyzer of the polarization microscope. In this case, depending on the orientation of the domain, it can be classified into three types of interference colors of blue, yellow and magenta. Of the total area of each color, the smallest area ratio is represented by Cmin.
  • the orientation is random, which means that the anisotropic structure does not grow significantly, and when the direction is small, the anisotropic structures are aligned and the anisotropic structure grows greatly.
  • Cmin which represents the randomness of the orientation of the optically anisotropic domain of the graphite material (I), is preferably 20% or less, more preferably 15% or less, still more preferably 12% or less. If Cmin is 20% or less, the anisotropic structure grows sufficiently and the discharge capacity increases.
  • the intensity ratio ID/IG (R value) to the peak intensity (IG) in the range of 1620 cm ⁇ 1 is 0.09 or more, preferably 0.10 or more, more preferably 0.12 or more.
  • ID/IG (R value) is 0.09 or more, the barrier for lithium in/out is lowered, and the current load characteristics are likely to be improved.
  • the ID/IG (R value) is 0.40 or less, preferably 0.30 or less, and more preferably 0 or 20 or less. When ID/IG (R value) is 0.40 or less, excessive exposure of highly active edge portions can be suppressed, and Coulombic efficiency can be increased.
  • the 50% particle size (D50) in the volume-based particle size distribution by the laser diffraction method of the graphite material (I) is preferably 6.0 ⁇ m or more, more preferably 10 ⁇ m. It is at least 0.0 ⁇ m, more preferably at least 15.0 ⁇ m.
  • the D50 is 6.0 ⁇ m or more, the coatability is increased, the production efficiency is improved, and the Coulombic efficiency is easily increased.
  • the D50 is preferably 30.0 ⁇ m or less, more preferably 29.0 ⁇ m or less, and further preferably 27.0 ⁇ m or less from the viewpoint of enhancing rate characteristics.
  • the 10% particle size (D10) in the volume-based particle size distribution of the graphite material (I) measured by the laser diffraction method is preferably 1.0 ⁇ m or more, more preferably 4.0 ⁇ m or more, and further preferably from the viewpoint of enhancing cycle characteristics. Is 7.0 ⁇ m or more.
  • the D10 is preferably 16.0 ⁇ m or less. When the D10 is 16.0 ⁇ m or less, a thin electrode can be manufactured, which is advantageous for increasing the energy density.
  • the 90% particle diameter (D90) in the volume-based particle diameter distribution of the graphite material (I) by the laser diffraction method is preferably 25.0 ⁇ m or more. Further, the D90 is preferably 80.0 ⁇ m or less, more preferably 70.0 ⁇ m or less, and further preferably 50.0 ⁇ m or less, from the viewpoint that a thin electrode can be manufactured and it is advantageous for increasing the energy density. ..
  • the volume-based particle size distribution by the laser diffraction method can be measured with a laser scattering diffraction type particle size distribution measuring device (MASTERSIZER manufactured by MALVERN).
  • MASTERSIZER manufactured by MALVERN.
  • the BET specific surface area of the graphite material (I) is preferably 0.5 m 2 /g or more, more preferably 0.8 m 2 /g or more, further preferably from the viewpoint of enhancing rate characteristics. Is 1.0 m 2 /g or more.
  • the BET specific surface area from the viewpoint that it is possible to increase the coulombic efficiency and cycle characteristics, preferably not more than 6.0 m 2 / g, more preferably 4.0 m 2 / g or less, more preferably 3.0 m 2 / g or less.
  • the BET specific surface area can be measured using the BET specific surface area measuring device described in the examples.
  • Circularity The circularity of the graphite material (I) is preferably 0.89 or more, more preferably 0.90 or more, from the viewpoint that the energy density can be increased. Further, the circularity is preferably 0.98 or less, more preferably 0.96 or less from the viewpoint that the number of particles contact each other and the rate characteristics are improved. The circularity can be measured using the circularity measuring device described in the examples.
  • the uniformity of particle size (D60/D10) in the graphite material (I) is preferably 1.5 or more, more preferably 1.8 or more, and further preferably 2.0 or more, from the viewpoint of excellent electrode coatability of the particles. Is. Further, the uniformity of particle size (D60/D10) is preferably 3.0 or less, more preferably 2.8 or less, and further preferably 2.6 or less. When D60/D10 is 3.0 or less, the uniformity is low, that is, the width of the particle size distribution is narrow, and the electrode density can be increased.
  • D60 is a 60% particle size in the volume-based particle size distribution by the laser diffraction method
  • D10 is a 10% particle size in the volume-based particle size distribution by the laser diffraction method.
  • the amount of surface oxygen between the surface of the particle and 40 nm in the depth direction measured from the peak intensity of O1s obtained by HAX-PES measurement using hard X-ray of 7940 eV, is: It is preferably 0.010% by mass or more, and more preferably 0.015% by mass.
  • the amount of surface oxygen is preferably 0.040 mass% or less, more preferably 0.030 mass% or less. When the amount of surface oxygen is 0.040 mass% or less, the conductivity of the graphite material is not adversely affected and the resistance can be suppressed low, so that the rate characteristics can be maintained high.
  • a method for producing graphite material (I) according to one embodiment of the present invention comprises crushing a carbon material. To obtain carbon particles, and a graphitization step of heat-treating the carbon particles at 2800° C. or more and 3300° C. or less to obtain a graphite material.
  • production method (II) comprises crushing a carbon material. To obtain carbon particles, and a graphitization step of heat-treating the carbon particles at 2800° C. or more and 3300° C. or less to obtain a graphite material.
  • the carbon material is not limited, for example, petroleum pitch, coal pitch, coal coke, petroleum coke, petroleum-derived bulk mesophase carbon, petroleum-derived mesophase microbeads, coal-derived bulk mesophase carbon, coal-derived mesophase microbeads, and mixtures thereof. It is preferably selected from those that have been heat treated. Among them, petroleum-derived bulk mesophase carbon, petroleum-derived mesophase microbeads, coal-derived bulk mesophase carbon, coal-derived mesophase microbeads, petroleum-derived mesophase pitch, coal-derived mesophase pitch, and petroleum coke are more preferable, and petroleum coke is further preferable.
  • Particularly preferred is petroleum coke obtained from crude oil having a paraffin content of 40% or more.
  • the paraffin content is preferably 40% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, a graphite material having a large optically anisotropic domain can be obtained, and high energy density and high cycle characteristics can be obtained. It's easy to get a point battery
  • Paraffin content is obtained from the mass of paraphene component when the total amount of paraffinic component, aromatic component, resin component and asphaltene component of crude oil component is 100% by mass.
  • the TLC-FID method can be used, and it can be measured by Iotroscan (manufactured by LSI Rulece Co., Ltd.).
  • the mass reduction in this temperature range is preferably 0.1% by mass or more.
  • the mass reduction is 0.1% by mass or more, the particle shape is likely to be agglomerate or spherical at the time of pulverization, the electrode is likely to have a high density, and the side reaction with the electrolytic solution is reduced when used as the negative electrode. ..
  • the reason for this is presumed that the component volatilized by heating from 300° C. to 1200° C. stabilizes the crystal of the exposed edge portion during graphitization.
  • the mass reduction is preferably 3.0 mass% or less from the viewpoint that particles after graphitization are less bound to each other and the yield is good.
  • the loss on heating can be measured by using a commercially available device capable of simultaneous differential thermal/thermogravimetric measurement (TG-DTA) at a heating rate of 10° C./min.
  • TG-DTA simultaneous differential thermal/thermogravimetric measurement
  • Seiko Instruments' TGDTAw6300 is used, about 15 mg of a measurement sample is accurately measured, placed on a platinum pan and set in the apparatus, and argon gas is flown at 200 ml/min to 300 at 10° C./min. The temperature is raised from °C to 1200 °C and measured.
  • ⁇ -alumina manufactured by Wako Pure Chemical Industries which has been previously treated at 1500° C. for 3 hours to remove volatile components, is used.
  • [2-2] Crushing Step Although the method of crushing the carbon material is not limited, it can be carried out using a commercially available crusher such as a jet mill, a hammer mill, a roller mill, a pin mill and a vibration mill. It is also possible to use two or more types of these pulverizers and pulverize in two stages. Carbon particles are obtained by crushing the carbon material.
  • a commercially available crusher such as a jet mill, a hammer mill, a roller mill, a pin mill and a vibration mill. It is also possible to use two or more types of these pulverizers and pulverize in two stages. Carbon particles are obtained by crushing the carbon material.
  • the maximum thermal history of the carbon material is preferably 600°C or lower.
  • the maximum heat history is 600° C. or less, the carbon material is not crushed into scales during crushing and a large amount of edge surface is not exposed, and when used as a negative electrode after graphitization, a side reaction with an electrolytic solution occurs. Less.
  • the carbon particles are preferably heat-treated at 800°C or higher and 1500°C or lower.
  • Heat treatment at 800° C. or higher lowers the resistance value during graphitization and increases productivity.
  • the heat treatment temperature is more preferably 900° C. or higher, further preferably 1000° C. or higher.
  • the volatile components of the carbon material appropriately remain and the surface of the graphite material (I) becomes in an appropriate state.
  • the heat treatment temperature is more preferably 1400° C. or lower, still more preferably 1300° C. or lower.
  • the method of heat treatment is not limited, for example, a rotary kiln, a roller hearth kiln, or a batch type baking furnace can be used, and it is preferable to perform the heat treatment in an inert gas atmosphere.
  • the angle of repose of the carbon particles is preferably 30° or more, more preferably 32° or more. If the angle of repose is less than 30°, the fluidity of the carbon material becomes high, so that the carbon material may scatter during charging into the furnace body or powder may be ejected during energization. Further, the angle of repose is preferably 50° or less, more preferably 45° or less, and further preferably 40° or less. When the angle of repose exceeds 50°, the fluidity of the carbon material decreases, the filling property in the furnace body decreases, the productivity decreases, and the energization resistance of the entire furnace may increase extremely.
  • the angle of repose can be measured using a tap denser. Specifically, using KYT-4000 manufactured by Seishin Enterprise Co., Ltd., 50 g of a measurement sample was allowed to freely fall from a dedicated inlet on the upper part of the device, and deposited in a triangular pyramid shape on an attached table, and then the table and the triangular pyramid.
  • the angle of repose can be obtained by measuring the rising angle of the protractor with a protractor.
  • the compression ratio ((solidified bulk density-relaxed bulk density)/relaxed bulk density) calculated from the loosened bulk density (0 times tapping) and the compacted bulk density (tap density) of the carbon particles is 20% or more and 50% or less. preferable. Within this range, it is possible to obtain an electrode slurry which has good fluidity and is easily applied onto the current collector when preparing an electrode slurry kneaded with a binder and a solvent.
  • the loosened bulk density is the density obtained by dropping 100 g of a sample from a height of 20 cm into a graduated cylinder and measuring the volume and mass without applying vibration.
  • the solidified bulk density (tap density) is a density obtained by measuring the volume and mass of 100 g of powder tapped 400 times using a Kantachrome auto tap.
  • the circularity of the carbon particles is preferably 0.89 or more, more preferably 0.90 or more, from the viewpoint that the density can be increased and the heat can be uniformly distributed during graphitization. Further, the circularity is preferably 0.98 or less, more preferably 0.96 or less from the viewpoint of increasing contact between particles and increasing heat generation efficiency during graphitization.
  • the uniformity of the particle size (D60/D10) of the carbon particles is preferably 1.5 or more, more preferably 1.8 or more, and further preferably 2.0 or more.
  • the uniformity is low, that is, the width of the particle size distribution is narrow, and the fluidity during graphitization is high and the heat is easily uniformly distributed.
  • D60/D10 is preferably 3.0 or less, more preferably 2.8 or less, still more preferably 2.6 or less from the viewpoint of good fluidity and excellent transportability.
  • the graphitization step in the production method (II) is not limited, it is preferably carried out by directly applying an electric current to the carbon particles to generate heat.
  • the method of directly passing an electric current through the carbon particles is not limited, but for example, it can be performed using a rectangular parallelepiped furnace body made of ceramic brick and having an open top.
  • a furnace body structure When such a furnace body structure is adopted, heat is uniformly applied to the carbon particles, so that there is an advantage that no aggregation occurs during graphitization. Further, since the temperature distribution is uniform and there is no trap portion for impurity volatilization, a graphite material with few impurities can be obtained.
  • the graphitization treatment is preferably performed in a non-oxidizing atmosphere.
  • a method of performing heat treatment in an atmosphere of an inert gas such as nitrogen gas, or a method of providing a layer for barrier to oxygen on the surface in contact with air can be mentioned.
  • the barrier layer for example, a method of separately providing a carbon plate or a carbon powder layer and consuming oxygen can be cited.
  • the graphitization temperature is preferably 2500° C. or higher, more preferably 2900° C. or higher, even more preferably 3000° C. or higher.
  • the upper limit of the graphitization temperature is preferably 3300° C. or lower from the viewpoint of preventing alteration due to sublimation of the material. It is preferable not to crush or crush the obtained graphite material after the graphitization treatment. By crushing or crushing after graphitization, the edge surface of the surface may be newly exposed and the performance may deteriorate.
  • a graphitization promoter such as a boron compound such as B 4 C or a silicon compound such as SiC.
  • the blending amount is preferably 10 mass ppm or more and 100000 mass ppm or less in the carbon material. This can increase the heat treatment efficiency and productivity of graphitization.
  • Negative Electrode Active Material of Lithium Ion Secondary Battery The negative electrode active material of the lithium ion secondary battery in one embodiment of the present invention (hereinafter also referred to as “negative electrode active material (III)”) is the above graphite material (I). Including.
  • the negative electrode active material (III) is made of the above graphite material (I) or further contains other graphite or carbon material. When containing other graphite or carbon material, it is preferable to add 0.01 to 20.00 parts by mass of the other graphite material or carbon material to 100.00 parts by mass of the graphite material (I). By mixing and using other graphite or carbon materials, a negative electrode active material having excellent characteristics of other graphite or carbon materials while maintaining the excellent characteristics of the graphite material (I) can be obtained. It is possible. From the same viewpoint, it is more preferable to add 0.01 to 10.00 parts by mass. As other graphite or carbon material, spherical natural graphite or artificial graphite is preferable.
  • the amount of carbon fiber blended is preferably 0.01 to 20.00 parts by mass, more preferably 0.500 to 5.00 parts by mass, relative to 100.00 parts by mass of the negative electrode active material (III).
  • carbon fibers examples include PAN-based carbon fibers, pitch-based carbon fibers, organic carbon fibers such as rayon-based carbon fibers, and vapor grown carbon fibers.
  • vapor grown carbon fiber having high crystallinity and high thermal conductivity is particularly preferable.
  • adhering carbon fibers to the surface of the composite carbon particles vapor grown carbon fibers are particularly preferable.
  • a commercially available mixer or stirrer can be used as a device for mixing the composite carbon particles and other materials.
  • mixers such as ribbon mixers, V-type mixers, W-type mixers, one-blade mixers and Nauta mixers.
  • Negative Electrode for Lithium Ion Secondary Battery contains the negative electrode active material (III). More specifically, the negative electrode (IV) comprises a current collector and a negative electrode mixture layer formed by applying a negative electrode mixture containing the negative electrode active material (III) and a binder onto the current collector. ..
  • the negative electrode mixture preferably contains a conductive auxiliary agent. Examples of the conductive aid include Denka Black (registered trademark, HS-100), VGCF (registered trademark)-H, and the like.
  • the current collector may be, for example, aluminum, nickel, copper, stainless steel foil, mesh, or the like.
  • the coating thickness of the negative electrode mixture is preferably 50 to 200 ⁇ m.
  • the method of applying the negative electrode mixture is not particularly limited, and examples thereof include a method of applying with a doctor blade or a bar coater and thereafter forming with a roll press or the like.
  • Examples of the pressure molding method include molding methods such as roll pressing and press pressing.
  • the pressure during pressure molding is preferably 1 ⁇ 10 3 to 3 ⁇ 10 3 kg/cm 2 .
  • binder examples include fluorine-based polymers such as polyvinylidene fluoride and polytetrafluoroethylene, and SBR (styrene butadiene rubber).
  • Lithium Ion Secondary Battery has a structure in which a positive electrode and a negative electrode are immersed in an electrolytic solution or an electrolyte.
  • the lithium ion secondary battery in one embodiment of the present invention comprises the above negative electrode (IV).
  • a lithium-containing transition metal oxide is usually used as a positive electrode active material, and preferably at least selected from Ti, V, Cr, Mn, Fe, Co, Ni, Mo and W.
  • a compound which is an oxide mainly containing at least one transition metal element selected from Fe, Co and Ni and lithium, and whose molar ratio of lithium to the transition metal is 0.3 to 2.2 is used.
  • a separator may be provided between the positive electrode and the negative electrode.
  • the separator include non-woven fabric containing polyolefin such as polyethylene and polypropylene as a main component, cloth, a microporous film, or a combination thereof.
  • electrolytes inorganic solid electrolytes, and polymer solid electrolytes can be used as the electrolyte solution and the electrolyte constituting the lithium ion secondary battery in the preferred embodiment of the present invention, but the organic electrolyte solution from the viewpoint of electrical conductivity is preferable.
  • the all-solid-state lithium-ion secondary battery has a structure in which the positive electrode and the negative electrode are in contact with the solid electrolyte layer.
  • FIG. 1 is a schematic diagram showing an example of the configuration of an all-solid-state lithium ion secondary battery 1 according to this embodiment.
  • the all-solid-state lithium-ion secondary battery 1 includes a positive electrode layer 11, a solid electrolyte layer 12, and a negative electrode layer 13.
  • the positive electrode 11 has a positive electrode current collector 111 and a positive electrode mixture layer 112.
  • the positive electrode current collector 111 is connected to a positive electrode lead 111a for exchanging charges with an external circuit.
  • the positive electrode current collector 111 is preferably a metal foil, and an aluminum foil is preferably used as the metal foil.
  • the positive electrode mixture layer 112 contains a positive electrode active material, and may further contain a solid electrolyte, a conductive additive, a binder, and the like.
  • the positive electrode active material include rock salt type layered active materials such as LiCoO 2 , LiMnO 2 , LiNiO 2 , LiVO 2 , and LiNi 1/3 Mn 1/3 Co 1/3 O 2 , spinel type active materials such as LiMn 2 O 4.
  • Olivine type active materials such as LiFePO 4 , LiMnPO 4 , LiNiPO 4 , LiCuPO 4 and sulfide active materials such as Li 2 S can be used. Further, these active materials may be coated with LTO (Lithium Tin Oxide), carbon or the like.
  • the content of the solid electrolyte in the positive electrode mixture layer 112 is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and 80 parts by mass or more with respect to 100 parts by mass of the positive electrode active material. Is more preferable.
  • the content of the solid electrolyte in the positive electrode mixture layer 112 is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and 125 parts by mass or less with respect to 100 parts by mass of the positive electrode active material. Is more preferable.
  • the conduction aid it is preferable to use a particulate carbonaceous conduction aid or a fibrous carbonaceous conduction aid.
  • a particulate carbonaceous conductive aid Denka Black (registered trademark) (manufactured by Denki Kagaku Kogyo Co., Ltd.), Ketjen Black (registered trademark) (manufactured by Lion Corporation), graphite fine powder SFG series (manufactured by Timcal), graphene Particulate carbon such as can be used.
  • VGCF vapor grown carbon fibers
  • VGCF registered trademark
  • VGCF registered trademark-H (manufactured by Showa Denko KK)
  • carbon nanotubes carbon nanohorns and the like
  • VGCF registered trademark
  • Vapor grown carbon fiber "VGCF (registered trademark)-H" manufactured by Showa Denko KK
  • the content of the conductive additive in the positive electrode mixture layer 112 is preferably 0.1 part by mass or more, and more preferably 0.3 part by mass or more, based on 100 parts by mass of the positive electrode active material.
  • the content of the conductive additive in the positive electrode mixture layer 112 is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less with respect to 100 parts by mass of the positive electrode active material.
  • binder examples include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl acetate, polymethacrylate, polyacrylate, polyacrylonitrile, polyvinyl alcohol, styrene-butadiene rubber, carboxymethyl cellulose and the like.
  • the content of the binder with respect to 100 parts by mass of the positive electrode active material is preferably 1 part by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 7 parts by mass or less.
  • the solid electrolyte layer 12 is interposed between the positive electrode layer 11 and the negative electrode layer 13, and serves as a medium for moving lithium ions between the positive electrode layer 11 and the negative electrode layer 13.
  • the solid electrolyte layer 12 preferably contains at least one selected from the group consisting of a sulfide solid electrolyte and an oxide solid electrolyte, and more preferably contains a sulfide solid electrolyte.
  • sulfide solid electrolyte examples include sulfide glass, sulfide glass ceramics, Thio-LISICON type sulfide, and the like. More specifically, for example, Li 2 S-P 2 S 5 , Li 2 S-P 2 S 5 -LiI, Li 2 S-P 2 S 5 -LiCl, Li 2 S-P 2 S 5 -LiBr, Li 2 S-P 2 S 5 -Li 2 O, Li 2 S-P 2 S 5 -Li 2 O-LiI, Li 2 S-SiS 2 , Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -LiBr, Li 2 S-SiS 2 -LiCl, Li 2 S-SiS 2 -B 2 S 3 -LiI, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 S-B 2 S 3, Li 2 S—P 2 S 5 —Z
  • the sulfide solid electrolyte material may be amorphous, crystalline, or glass ceramics.
  • oxide solid electrolyte examples include perovskite, garnet, and LISICON type oxide. More specifically, for example, La 0.51 Li 0.34 TiO 2.94 , Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 , Li 7 La 3 Zr 2 O 12 , 50Li 4 SiO 4 .50Li 3 BO 3 , Li 2.9 PO 3.3. N 0.46 (LIPON), Li 3.6 Si 0.6 P 0.4 O 4, Li 1.07 Al 0.69 Ti 1.46 (PO 4) 3, Li 1.5 Al 0.5 Ge 1.5 (PO 4) may be mentioned 3 or the like.
  • the oxide solid electrolyte material may be amorphous, crystalline, or glass ceramics.
  • the negative electrode layer 13 includes a negative electrode current collector 131 and a negative electrode mixture layer 132.
  • the negative electrode current collector 131 is connected to a negative electrode lead 131a for exchanging charges with an external circuit.
  • the negative electrode current collector 131 is preferably a metal foil, and a stainless foil, a copper foil, or an aluminum foil is preferably used as the metal foil.
  • the surface of the current collector may be coated with carbon or the like.
  • the negative electrode mixture layer 132 contains a negative electrode active material, and may also contain a solid electrolyte, a binder, a conductive auxiliary agent, and the like.
  • the composite carbon particles are used as the negative electrode active material.
  • the materials mentioned in the solid electrolyte layer 12 may be used, but the solid electrolyte contained in the solid electrolyte layer 12 or the positive electrode mixture layer may be contained.
  • a material different from the existing solid electrolyte may be used.
  • the content of the solid electrolyte in the negative electrode mixture layer 132 is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and 80 parts by mass or more with respect to 100 parts by mass of the negative electrode active material. Is more preferable.
  • the content of the solid electrolyte in the negative electrode mixture layer 132 is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and 125 parts by mass or less with respect to 100 parts by mass of the negative electrode active material. Is more preferable.
  • the conductive auxiliary agent that may be included in the negative electrode mixture layer 132 the conductive auxiliary agents described in the description of the positive electrode mixture layer 112 can be used, but the conductive auxiliary agent included in the positive electrode mixture layer 112 is used. Different materials may be used.
  • the content of the conductive additive in the negative electrode mixture layer 132 is preferably 0.1 part by mass or more, and more preferably 0.3 part by mass or more, with respect to 100 parts by mass of the negative electrode active material.
  • the content of the conductive additive in the negative electrode mixture layer 132 is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less with respect to 100 parts by mass of the negative electrode active material.
  • the binder for example, the materials mentioned in the description of the positive electrode mixture layer 112 can be used, but the binder is not limited to these.
  • the content of the binder based on 100 parts by mass of the negative electrode active material is preferably 0.3 parts by mass or more and 10 parts by mass or less, and 0.5 parts by mass or more and 5 parts by mass or less. More preferable.
  • BET Specific Surface Area BET Specific Surface Area Measuring Device Quantrome NOVA 2200e A 3 g sample was placed in a measurement cell (9 mm ⁇ 135 mm), dried at 300° C. for 1 hour under vacuum, and then measured. N 2 was used as the gas for measuring the BET specific surface area.
  • the obtained mixture (about 5 ml) was slowly poured into the sample container until the height became about 1 cm, and the mixture was allowed to stand for 1 day to cure. Next, the cured sample was taken out and the double-sided tape was peeled off. Then, the surface to be measured was polished using a polishing plate rotary type polishing machine.
  • Polishing was performed by pressing the polishing surface against the rotating surface.
  • the rotation speed of the polishing plate is 1000 rpm.
  • the polishing plate count is #500, #1000, #2000 in this order, and the last is alumina (trade name: Baicalox type 0.3CR, particle size 0.3 ⁇ m, manufacturing company: Baikowski, sales company: Baikou It was mirror-polished using (Ski Japan).
  • the polished sample was fixed on the slide with clay, and 10 spots were randomly observed in a reflection mode using a polarization microscope (BX51, manufactured by OLYMPUS).
  • a square area (100 ⁇ m square) was cut out from the same point at an observation angle of 0° and 45°, and the images of the selected magnifications were subjected to the following analysis for all particles within that range to obtain an average.
  • the color of the optically anisotropic domain changes depending on the orientation of the crystallites, the probability of facing straight ahead is extremely low. Therefore, even if magenta is shown, the wavelength is almost different from that of pure magenta.
  • the optically isotropic domain always exhibits a pure magenta wavelength. Therefore, in the present invention, all of pure magenta is identified as an optical isotropic region.
  • the command of LUZEX AP was used, and the extraction width of each color was set by setting the IHP data as shown in Table 1 below.
  • the W-1 command of ELIMINATE1 of the logical filter is used to remove the area of 1 dot or less.
  • the number of pixels was used to calculate the total number of pixels in the image and the number of pixels of the corresponding color.
  • the area ratio of the portion where the color changed when the sample was rotated 0°, 45°, and 90° with respect to the analyzer of the polarization microscope was calculated as shown in Table 2.
  • the voids of the carbon material mean voids in the particles, and voids between particles are not included.
  • Raman spectroscopic analysis Raman spectroscopic device: JASCO Corporation NRS-5100 Excitation wavelength 532.36Nm, entrance slit width 200 [mu] m, the exposure time of 15 seconds, the number of integrations twice, was measured under the conditions of the diffraction grating 600 / mm, the intensity of the peak in the range of 1300 ⁇ 1400 cm -1 and (ID) The intensity ratio of the intensity (IG) of the peak in the range of 1580 to 1620 cm -1 was defined as the R value (ID/IG).
  • Circularity Circularity measuring device Flow type particle image analyzer FPIA-3000 (manufactured by Sysmex Corporation) The circularity is obtained by dividing the circumference of a circle having the same area as the observed area of a particle image by the circumference of the particle image, and the closer to 1 the closer the circle is to a perfect circle.
  • the graphite material was purified by passing through a filter having an opening of 106 ⁇ m, 0.1 g of the sample was added to 20 ml of ion-exchanged water, and 0.1 to 0.5% by mass of a surfactant was added to uniformly disperse the graphite material.
  • a sample solution for measurement was prepared. Dispersion was performed by using an ultrasonic cleaner UT-105S (manufactured by Sharp Manufacturing System) for 5 minutes. The obtained sample solution for measurement was put into an apparatus, and the median of circularity was calculated from the number-based frequency distribution of circularity analyzed for 10,000 particles in the LPF mode.
  • Electrode preparation, electrode density After adding NMP to the base material stock solution to adjust the viscosity, it was applied on a high-purity copper foil to a thickness of 250 ⁇ m using a doctor blade. This was vacuum dried at 120° C. for 1 hour, punched into 18 mm ⁇ , and the punched electrodes were sandwiched between super steel press plates and pressed against the electrodes at a pressure of 2 t/cm 2 . Then, it was dried at 120° C. for 12 hours in a vacuum dryer to obtain an evaluation electrode. The mass of the active material at this time was divided by the volume of the active material to obtain the electrode density (g/cm 3 ).
  • a battery was manufactured as follows. The following operations were carried out in a dry argon atmosphere with a dew point of -80°C or lower. In a cell with a polypropylene screw-in lid (inner diameter of about 18 mm), a copper foil electrode and a metallic lithium foil prepared in [7-8-2] above were separated with a separator (polypropylene microporous film (Cell Guard 2400)). It was sandwiched and laminated. An electrolytic solution was added to this and a lid was provided to obtain a battery for evaluation. As the electrolytic solution, a mixed solution of 8 parts by mass of EC (ethylene carbonate) and 12 parts by mass of DEC (diethyl carbonate) in which 1 mol/liter of LiPF 6 was dissolved as an electrolyte was used.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • the discharge capacity was defined as the value obtained by dividing the quantity of electricity during the first discharge by the weight of the graphite material for the negative electrode of the lithium-ion secondary battery. Further, the discharge capacity (0.2 C) was multiplied by the electrode density to obtain the volume energy density. Further, the ratio of the charge capacity at the time of initial charge and the discharge capacity at the time of first discharge, that is, the value obtained by expressing the ratio of initial discharge capacity/initial charge capacity in percentage was taken as the Coulombic efficiency.
  • Rate characteristic The rate characteristic was measured in a constant temperature bath set at 25°C.
  • CC constant current: constant current
  • CV constant volt: constant voltage
  • discharge release from carbon
  • a constant-current constant-voltage discharge test was performed at current densities of 0.2 C and 3 C, and cutoff was performed at a voltage of 1.5 V.
  • the value of discharge capacity (3C)/discharge capacity (3C) was defined as the discharge rate characteristic.
  • Example 1 The petroleum coke obtained by using the delayed coking process on a Chinese crude oil having a paraffin content of 45% by mass was used as a carbon material. This was crushed with a Hosokawa Micron bantam mill, air classified with a Nisshin Engineering turbo classifier to D50 of 17.0 ⁇ m, and heat-treated at 1000° C. while flowing nitrogen gas with a Japanese insulator roller hearth kiln to obtain carbon particles 1 Got The physical properties of carbon particles 1 are summarized in Table 3.
  • a ceramic brick was used to form a furnace with a length of 500 mm, a width of 1000 mm, and a depth of 200 mm, and carbon electrode plates of 450 x 180 mm and a thickness of 20 mm were installed on both inner end surfaces.
  • the carbon particles 1 were packed in the furnace and a lid provided with a nitrogen gas inlet and an exhaust port was provided.
  • a transformer was installed, and heating was performed by passing an electric current between the electrode plates for about 5 hours while flowing a nitrogen gas, and graphitized at a maximum temperature of 3200° C. to obtain a graphite material 1.
  • Table 4 shows various physical properties of the obtained graphite material 1 and evaluation results of the lithium ion battery.
  • Example 2 Carbon particles 2 were obtained by the same production method as in Example 1 except that the carbon material was pulverized and classified so that D50 was 15.0 ⁇ m. The physical properties of carbon particles 2 are summarized in Table 3. Next, a graphite material 2 was obtained in the same manner as in Example 1 except that the obtained carbon particles 2 were used. Table 4 shows various physical properties of the obtained graphite material 2 and evaluation results of the lithium ion battery.
  • Example 3 Carbon particles 3 were obtained by the same production method as in Example 1 except that the carbon material was pulverized and classified so that D50 was 24.0 ⁇ m. Table 3 shows the physical properties of the carbon particles 3. Next, a graphite material 3 was obtained in the same manner as in Example 1 except that the obtained carbon particles 3 were used. Table 4 shows various physical properties of the obtained graphite material 3 and evaluation results of the lithium ion battery.
  • Example 4 Carbon particles 4 were obtained by the same production method as in Example 1 except that the carbon material was pulverized and classified so that D50 was 27.0 ⁇ m. Table 3 shows the physical properties of the carbon particles 4. Next, a graphite material 4 was obtained in the same manner as in Example 1 except that the obtained carbon particles 4 were used. Table 4 shows various physical properties of the obtained graphite material 4 and evaluation results of the lithium ion battery.
  • Example 5 The petroleum coke obtained by using the delayed coking process with respect to Chinese crude oil having a paraffin content of 65% by mass was used as a carbon material. This was crushed with a Hosokawa Micron bantam mill, air-flow classified with a Nisshin Engineering turbo classifier to D50 of 23.0 ⁇ m, and heat-treated at 1000° C. while flowing nitrogen gas with a Nippon Insulator roller hearth kiln to produce carbon particles 5 Got Table 3 shows the physical properties of the carbon particles 5. Next, a graphite material 5 was obtained in the same manner as in Example 1 except that the obtained carbon particles 5 were used. Table 4 shows various physical properties of the obtained graphite material 5 and evaluation results of the lithium ion battery.
  • Carbon particles 3 were filled in a graphite crucible with a screw lid and graphitized at a maximum temperature of 3200° C. using an Acheson furnace to obtain a graphite material 10.
  • Table 4 shows various physical properties of the obtained graphite material 10 and evaluation results of the lithium ion battery.
  • the obtained amorphous solid electrolyte is press-molded by a uniaxial press molding machine using a polyethylene die having an inner diameter of 10 mm ⁇ and a SUS punch to prepare the solid electrolyte layer 12 as a sheet having a thickness of 960 ⁇ m. ..
  • Negative Electrode Mixture Layer 132 Graphite material 48.5 parts by mass, solid electrolyte (Li 3 PS 4 , D50: 8 ⁇ m) 48.5 parts by mass, VGCF (registered trademark)-H (Showa Denko) (Manufactured by corporation) 3 parts by mass are mixed.
  • the mixture is homogenized by milling at 100 rpm for 1 hour using a planetary ball mill.
  • the homogenized mixture is 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 prepare the negative electrode mixture layer 132 as a sheet having a thickness of 65 ⁇ m.
  • the obtained layered product A was once taken out from the die, and the negative electrode lead 131a, the copper foil (the negative electrode current collector 131), and the layered product A with the negative electrode mixture layer 132 facing downward from the bottom in the die, aluminum.
  • the foil (positive electrode current collector 111) and the positive electrode lead 111a are stacked in this order, and sandwiched with a pressure of 1 MPa (10 kgf/cm 2 ) from both sides of the negative electrode lead 131a side and the positive electrode lead 111a side with a SUS punch, and the negative electrode lead 131a,
  • the copper foil, the laminate A, the aluminum foil, and the positive electrode lead 111a are joined to obtain the all-solid-state lithium ion secondary battery 1.
  • the discharge capacity (mAh) by the first constant current discharge is defined as the discharge capacity Qd1.
  • a value obtained by dividing the discharge capacity Qd1 (mAh) by the mass of the composite material in the negative electrode layer is defined as the discharge capacity density (mAh/g). Further, the ratio of the discharge capacity Qd1 to the charge capacity Qc1 is expressed as a percentage, and 100 ⁇ Qd1/Qc1 is taken as the Coulombic efficiency (%).
  • Cycle characteristics Charge is carried out by constant current charging of 5.0 mA (0.2 C) until it reaches 4.2 V, and then at a constant voltage of 4.2 V, the current value is 1.25 mA (0 C). Constant-voltage charging is performed until it decreases to .05C). The discharge is a constant current discharge of 25 mA (1.0 C) until the voltage reaches 2.75V. These charges and discharges are performed 100 times, and 100 ⁇ Qd100/Qd1 is taken as 100 cycle capacity retention rate (%) (cycle characteristics) as the discharge capacity Qd100 at the 100th time.
  • Table 5 shows the evaluation results of the all-solid-state lithium ion secondary batteries using the graphite materials 1, 6, 9, 11 obtained in the above Examples and Comparative Examples.

Abstract

Matériau de graphite pour une électrode négative d'une batterie secondaire au lithium-ion : ayant un intervalle de plan moyen d002 de (002) plans de 0,3354-0,3370 nm tel que déterminé par une mesure de diffraction à rayons X ; montrant que le rapport ID/IG entre une intensité (ID) d'un pic dans 1300-1400 cm-1 et une intensité (IG) d'un pic dans 1580-1620 cm-1 tel que déterminé respectivement par mesure spectroscopique Raman est de 0,09-0,40 ; présentant une rugosité de surface de 6,0-14,0 ; présentant des domaines optiquement anisotropes, dont la surface représente 95,0 à 99,0 % par rapport à 100,0 % de la surface totale totale des domaines optiquement anisotropes, des domaines optiquement isotropes et des vides ; et satisfaisant (1) 5 μm2≤Da(10)≤20 μm2, (2) 40 μm2≤Da(50)≤250 μm2, et (3) 200 μm2≤Da(90)≤500 μm2, la surface du domaine le plus grand étant définie Da(n) lorsqu'une valeur intégrée obtenue par intégration des zones des domaines optiquement anisotropes, en commençant par la plus petite, atteint n % de la surface totale de tous les domaines optiquement anisotropes.
PCT/JP2019/050171 2018-12-26 2019-12-20 Matériau de graphite pour électrode négative de batterie secondaire au lithium-ion WO2020137909A1 (fr)

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WO2022138753A1 (fr) * 2020-12-24 2022-06-30 昭和電工マテリアルズ株式会社 Électrode négative pour batterie tout solide, batterie tout solide, et matériau actif d'électrode négative pour batterie tout solide
WO2022215126A1 (fr) * 2021-04-05 2022-10-13 昭和電工マテリアルズ株式会社 Matériau d'électrode négative pour batterie secondaire au lithium-ion, électrode négative pour batterie secondaire au lithium-ion et batterie secondaire au lithium-ion

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JPH04190555A (ja) * 1990-11-22 1992-07-08 Osaka Gas Co Ltd リチウム二次電池
JPH07320740A (ja) * 1993-02-25 1995-12-08 Kureha Chem Ind Co Ltd 二次電池電極用炭素質材料
JPH0831410A (ja) * 1994-07-13 1996-02-02 Toshiba Battery Co Ltd リチウム二次電池
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