WO2018056280A1 - Électrode négative pour éléments accumulateurs d'électricité à électrolyte non aqueux, et élément accumulateur d'électricité à électrolyte non aqueux - Google Patents

Électrode négative pour éléments accumulateurs d'électricité à électrolyte non aqueux, et élément accumulateur d'électricité à électrolyte non aqueux Download PDF

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WO2018056280A1
WO2018056280A1 PCT/JP2017/033807 JP2017033807W WO2018056280A1 WO 2018056280 A1 WO2018056280 A1 WO 2018056280A1 JP 2017033807 W JP2017033807 W JP 2017033807W WO 2018056280 A1 WO2018056280 A1 WO 2018056280A1
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negative electrode
active material
electrode active
material layer
nonaqueous electrolyte
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PCT/JP2017/033807
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English (en)
Japanese (ja)
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卓 千澤
青木　寿之
裕章 遠藤
博 降矢
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株式会社Ｇｓユアサ
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/38—Carbon pastes or blends; Binders or additives therein
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a negative electrode for a nonaqueous electrolyte storage element and a nonaqueous electrolyte storage element.
  • Nonaqueous electrolyte secondary batteries typified by lithium ion secondary batteries are widely used in electronic devices such as personal computers and communication terminals, automobiles and the like because of their high energy density.
  • the non-aqueous electrolyte secondary battery generally includes an electrode body having a pair of electrodes electrically separated by a separator, and a non-aqueous electrolyte interposed between the electrodes, and transfers ions between both electrodes. It is configured to charge and discharge by performing.
  • capacitors such as lithium ion capacitors and electric double layer capacitors are widely used as power storage elements other than secondary batteries.
  • a carbon material is widely used as an active material of a negative electrode provided in such a power storage element.
  • This carbon material is roughly classified into a carbonaceous material (amorphous carbon) having low crystallinity and graphite having high crystallinity.
  • the carbonaceous material has a structure in which crystal planes are irregularly stacked. For this reason, in the case of a carbonaceous material, since the ion insertion / desorption reaction proceeds on a relatively large number of surfaces, the resistance of the ion insertion / desorption reaction is low, and a storage element having good high-rate discharge characteristics is obtained. It is said that it is easy to obtain.
  • graphite has a structure in which hexagonal crystal planes of carbon atoms are regularly stacked.
  • the present invention has been made based on the circumstances as described above, and an object thereof is a non-aqueous electrolyte power storage capable of increasing the capacity retention rate of a non-aqueous electrolyte power storage element using a carbonaceous material as a negative electrode active material.
  • One embodiment of the present invention made to solve the above problems includes a negative electrode active material layer, the negative electrode active material layer contains a carbonaceous material, and the content of the carbonaceous material in the negative electrode active material layer is
  • the negative electrode for a non-aqueous electrolyte electricity storage element is 90% by mass or more and the surface roughness of the negative electrode active material layer is 0.4 ⁇ m or less.
  • capacitance maintenance factor of the nonaqueous electrolyte electrical storage element using a carbonaceous material as a negative electrode active material can be raised.
  • FIG. 1 is an external perspective view showing a secondary battery according to an embodiment of the present invention.
  • FIG. 2 is a schematic diagram showing a power storage device configured by assembling a plurality of secondary batteries according to an embodiment of the present invention.
  • One embodiment of the present invention includes a negative electrode active material layer, the negative electrode active material layer contains a carbonaceous material, and the content of the carbonaceous material in the negative electrode active material layer is 90% by mass or more.
  • This is a negative electrode for a nonaqueous electrolyte storage element (hereinafter, also simply referred to as “negative electrode”) in which the surface roughness of the active material layer is 0.4 ⁇ m or less.
  • the capacity retention rate of the nonaqueous electrolyte storage element can be increased.
  • the reason why such an effect occurs is not clear, but the following is presumed.
  • the surface of the negative electrode active material layer is rough, the reaction is likely to be uneven, which is one of the factors that decrease the capacity retention rate.
  • graphite has soft particles, when graphite is used for the negative electrode active material layer, even if the surface is rough, the surface roughness is reduced with repeated charge and discharge, and the decrease in capacity retention rate is suppressed.
  • the particles of the carbonaceous material are hard, when the negative electrode active material layer contains 90% by mass or more of the carbonaceous material, the surface roughness is difficult to be relaxed even by repeated charge and discharge.
  • a storage element using a carbonaceous material as a negative electrode active material has a low capacity retention rate. Therefore, in the negative electrode active material layer containing 90% by mass or more of the carbonaceous material, the surface roughness is reduced to 0.4 ⁇ m or less, so that uneven reaction on the surface of the negative electrode active material layer is reduced, and the discharge capacity of the storage element It is assumed that the maintenance rate will increase.
  • the “carbonaceous material” means a carbon material having an interlayer distance (d002) determined by a wide-angle X-ray diffraction method of 3.40 mm or more.
  • Surface roughness refers to the arithmetic average roughness (Ra) measured at a reference length of 25 ⁇ m in accordance with JIS-B-0601 (1994).
  • the carbonaceous material preferably contains non-graphitizable carbon. Since the non-graphitizable carbon particles have higher hardness than other carbonaceous materials, the effect of increasing the capacity retention rate of the electricity storage device can be increased when non-graphitizable carbon is used.
  • non-graphitizable carbon means that it does not convert to graphite even when heated to an ultrahigh temperature of about 3300 K at normal pressure, and the interlayer distance (d002) determined by wide-angle X-ray diffraction method is 3.60 mm. The above carbonaceous material is meant.
  • Graphite means a carbon material having an interlayer distance (d002) determined by a wide-angle X-ray diffraction method of less than 3.40 mm.
  • the carbonaceous material preferably has an average particle size of 4 ⁇ m or less.
  • the “average particle size” means a value (D50) at which the volume-based integrated distribution calculated according to JIS-Z-8819-2 (2001) is 50%. Specifically, it can be measured by the following method. Measurement is performed using a laser diffraction particle size distribution measuring apparatus (“SALD-2200” manufactured by Shimadzu Corporation) as a measuring apparatus and WingSALD-2200 as measurement control software. A scattering measurement mode is employed, and laser light is irradiated to a wet cell in which a dispersion liquid in which a measurement target sample (carbonaceous material) is dispersed in a dispersion solvent circulates to obtain a scattered light distribution from the measurement sample.
  • SALD-2200 laser diffraction particle size distribution measuring apparatus
  • a scattering measurement mode is employed, and laser light is irradiated to a wet cell in which a dispersion liquid in which a measurement target sample (carbonaceous material) is dispersed in a dispersion solvent circulates to obtain a scattered light distribution from the measurement sample.
  • the scattered light distribution is approximated by a lognormal distribution, and the particle diameter corresponding to a cumulative degree of 50% (D50) is defined as the average particle diameter.
  • D50 cumulative degree of 50%
  • the average particle size based on the above measurement is approximately the same as the average particle size measured by extracting 100 carbonaceous materials from the SEM image of the negative electrode while avoiding extremely large carbonaceous materials and extremely small carbonaceous materials. It is confirmed that they match.
  • Nonaqueous electrolyte storage element (hereinafter also simply referred to as “storage element”) including the negative electrode.
  • the power storage element can have a high capacity retention rate while including a negative electrode having a carbonaceous material as a negative electrode active material.
  • the negative electrode which concerns on one Embodiment of this invention has a negative electrode base material and the negative electrode active material layer distribute
  • the negative electrode substrate is a conductive substrate.
  • a material of the negative electrode substrate metals such as copper, nickel, stainless steel, nickel-plated steel or alloys thereof are used, and copper or copper alloys are preferable.
  • foil, a vapor deposition film, etc. are mentioned as a formation form of a negative electrode base material, and foil is preferable from the surface of cost. That is, copper foil is preferable as the negative electrode substrate. Examples of the copper foil include rolled copper foil and electrolytic copper foil. “Conductive” means that the volume resistivity measured in accordance with JIS-H-0505 (1975) is 107 ⁇ ⁇ cm or less, and “nonconductive” It means that the volume resistivity is more than 107 ⁇ ⁇ cm.
  • middle layer is a coating layer of the surface of a negative electrode base material, for example, and can reduce the contact resistance of a negative electrode base material and a negative electrode active material layer by including electroconductive particles, such as a carbon particle.
  • middle layer is not specifically limited, For example, it can form with the composition containing a resin binder and electroconductive particle.
  • the negative electrode active material layer is formed from a negative electrode active material layer forming material containing a carbonaceous material.
  • the carbonaceous material is used as a negative electrode active material.
  • the negative electrode active material layer forming material includes optional components such as a negative electrode active material other than the carbonaceous material, a binder (binder) such as an elastomer, a conductive agent, a thickener, and a filler as necessary.
  • the carbonaceous material is so-called amorphous carbon, and examples thereof include non-graphitizable carbon (hard carbon); graphitizable carbon (soft carbon) such as coke and pyrolytic carbon.
  • the shape of the carbonaceous material is not particularly limited, and examples thereof include particles and plates.
  • the upper limit of the average particle diameter of the carbonaceous material is not particularly limited, and may be, for example, 20 ⁇ m, but is preferably 10 ⁇ m, more preferably 6 ⁇ m, and further preferably 4 ⁇ m.
  • a carbonaceous material having such an average particle size it is easy to obtain high rate discharge characteristics, and the surface of the negative electrode active material layer is in a better state. The rate can be increased.
  • a minimum of the average particle diameter of the said carbonaceous material it is 0.5 micrometer, for example, and may be 2 micrometers.
  • Content in the negative electrode active material layer of the said carbonaceous material is 90 mass% or more.
  • the content of the carbonaceous material in the negative electrode active material layer is 90% by mass or more, the surface of the negative electrode active material layer becomes hard, and the roughness of the surface of the negative electrode active material layer is not relaxed even by repeated charge and discharge. It is in.
  • the capacity retention rate can be increased by setting the surface roughness of the negative electrode active material layer to 0.4 ⁇ m or less.
  • the negative electrode active material layer of the carbonaceous material when the content in the negative electrode active material layer of the carbonaceous material is less than 90% by mass (specifically, in the negative electrode obtained by mixing non-graphitizable carbon and graphite, the negative electrode active material layer of non-graphitizable carbon In the case where the content of is 80%, the effect of the present invention is hardly obtained.
  • the negative electrode active material layer preferably contains only a carbonaceous material as the negative electrode active material.
  • the upper limit of the carbonaceous material can be 99% by mass.
  • the negative electrode active material layer may contain a negative electrode active material other than the carbonaceous material.
  • negative electrode active materials that may be contained in the negative electrode active material layer include known materials that are commonly used. Examples thereof include metals or semimetals such as Si and Sn; Si oxides, Sn oxides, and the like. Metal oxides or metalloid oxides; polyphosphoric acid compounds; graphite. Examples of the semimetal include B, Si, Ge, As, Sb, Te, Po, At and the like.
  • binder examples include elastomers such as ethylene-propylene-diene rubber (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), and fluorine rubber; fluorine resin (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.) , Thermoplastic resins such as polyethylene, polypropylene, and polyimide.
  • EPDM ethylene-propylene-diene rubber
  • SBR sulfonated EPDM
  • SBR styrene butadiene rubber
  • fluorine rubber fluorine resin
  • PTFE polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • Thermoplastic resins such as polyethylene, polypropylene, and polyimide.
  • an elastomer is preferable, and SBR is more preferable.
  • SBR is more preferable.
  • the lower limit of the content of the elastomer in the negative electrode active material layer is preferably 0.5% by mass, and more preferably 1% by mass.
  • the upper limit of this content is preferably 5% by mass, and more preferably 3% by mass.
  • aqueous solvent water or a solvent mainly composed of water
  • examples of the binder that can use an aqueous solvent include fluororesins such as PTFE, elastomers such as SBR, and other vinyl acetate copolymers. That is, an elastomer such as SBR is particularly preferable as a binder from the viewpoints of smoothness, production cost, environmental load reduction, and the like.
  • the content of the carbonaceous material in the negative electrode active material layer is preferably 95% by mass or more.
  • the content of the binder can be reduced, so that the capacity of the negative electrode can be increased and the surface roughness of the negative electrode active material layer can be reduced.
  • the glass transition temperature (Tg) of the binder is not particularly limited, but is preferably 25 ° C. or lower. If the glass transition temperature (Tg) of the binder is 25 ° C. or less, it is considered that the binder tends to uniformly cover the surface of the carbonaceous material particles. As a result, when the negative electrode active material layer is pressed, the negative electrode active material layer is uniformly pressed, which makes it easy to control the surface smoothness to a good state. Can be further enhanced.
  • the conductive agent is not particularly limited as long as it is a conductive material that does not adversely affect battery performance.
  • a conductive agent include metals, conductive ceramics, carbon materials such as carbon black, and the like.
  • Examples of the shape of the conductive agent include powder and fiber.
  • thickener examples include polysaccharide polymers such as carboxymethylcellulose (CMC) and methylcellulose.
  • CMC carboxymethylcellulose
  • the thickener is preferably deactivated by methylation or the like.
  • the negative electrode active material layer preferably contains CMC.
  • CMC is contained in the negative electrode active material layer
  • the surface of the carbonaceous material particles is covered with CMC, so that the surface of the negative electrode active material layer can be made smoother.
  • the content of CMC with respect to the negative electrode active material layer is preferably 0.5 to 1.5% by mass.
  • the content of CMC is less than 0.5% by mass, the amount covering the particle surface decreases, and when it exceeds 1.5% by mass, the resistance increase of the negative electrode increases.
  • the filler is not particularly limited as long as it does not adversely affect battery performance.
  • the main component of the filler include polyolefins such as polypropylene and polyethylene, silica, alumina, zeolite, and glass.
  • the upper limit of the surface roughness (Ra) of the negative electrode active material layer is preferably 0.4 ⁇ m, and more preferably 0.29 ⁇ m. By setting the surface roughness of the negative electrode active material layer to 0.29 ⁇ m or less, the capacity retention rate of the power storage element can be further increased as described above.
  • the lower limit of the surface roughness (Ra) is not particularly limited, but is preferably 0.05 ⁇ m, more preferably 0.1 ⁇ m, and further preferably 0.15 ⁇ m. By setting the surface roughness of the negative electrode active material layer to be equal to or higher than the above lower limit, a sufficient surface area can be secured, and the charge / discharge characteristics of the power storage element can be further improved.
  • the surface roughness of the negative electrode active material layer is adjusted by adjusting the particle diameter of the carbonaceous material, the solid content concentration of the negative electrode active material layer forming material (slurry), and the coating of the negative electrode active material layer (negative electrode active material layer forming material). It can be performed by controlling a plurality of factors such as the presence or absence of pressing on the subsequent coating film) and the press strength.
  • the upper limit of the maximum height (Ry) of the negative electrode active material layer is preferably 2.2 ⁇ m, more preferably 1.5 ⁇ m.
  • the lower limit of the maximum height (Ry) is preferably 0.5 ⁇ m, and more preferably 1.0 ⁇ m.
  • the upper limit of the ten-point average roughness (Rz) of the negative electrode active material layer is preferably 1.1 ⁇ m, and more preferably 0.8 ⁇ m.
  • the lower limit of the ten-point average roughness (Rz) is preferably 0.3 ⁇ m, and more preferably 0.6 ⁇ m.
  • the upper limit of the average interval (Sm) of the unevenness of the negative electrode active material layer is preferably 6 ⁇ m, and more preferably 4 ⁇ m. On the other hand, as a minimum of this average interval (Sm) of unevenness, 1.5 micrometers is preferred and 2 micrometers is more preferred. By setting the average interval (Sm) of the unevenness of the negative electrode active material layer within the above range, the capacity retention rate can be increased.
  • the upper limit of the average distance (S) between the local peaks of the negative electrode active material layer is preferably 0.85 ⁇ m, and more preferably 0.7 ⁇ m.
  • the lower limit of the average interval (S) between the local peaks is preferably 0.3 ⁇ m, and more preferably 0.5 ⁇ m.
  • the upper limit of the root mean square roughness (Rms) of the negative electrode active material layer is preferably 0.5 ⁇ m, and more preferably 0.35 ⁇ m.
  • the lower limit of the root mean square roughness (Rms) is preferably 0.15 ⁇ m, more preferably 0.2 ⁇ m.
  • the maximum height (Ry), ten-point average roughness (Rz), average interval of irregularities (Sm), average interval between local peaks (S), and mean square roughness (Rms) are JIS-B- In accordance with 0601 (1994), it indicates each value measured at a reference length of 25 ⁇ m.
  • the average thickness of the negative electrode active material layer is not particularly limited, but the lower limit is preferably 3 ⁇ m, more preferably 5 ⁇ m, and even more preferably 10 ⁇ m.
  • the upper limit of the average thickness is preferably 75 ⁇ m, more preferably 60 ⁇ m, and even more preferably 50 ⁇ m.
  • the negative electrode can be obtained by laminating a negative electrode active material layer directly or via an intermediate layer on the negative electrode substrate.
  • the intermediate layer can be obtained by applying an intermediate layer forming material to the negative electrode substrate.
  • the lamination of the negative electrode active material layer can be obtained by coating and drying a slurry-like negative electrode active material layer forming material.
  • the negative electrode active material layer forming material includes a carbonaceous material, a binder, and a dispersion medium (solvent).
  • the surface roughness of the negative electrode mixture layer is the particle size of the carbonaceous material, the solid content concentration of the negative electrode active material layer forming material (slurry), the presence or absence of pressing of the negative electrode mixture layer, and the press strength (press pressure). It can be adjusted by a plurality of factors such as. For example, when carbonaceous particles having the same particle diameter are used, it is preferable that the solid content concentration of the slurry-like negative electrode active material layer forming material is higher.
  • the presence or absence of a press to a negative mix layer and press strength differ with the difference in the particle diameter of a carbonaceous particle.
  • the press linear pressure is 2000 N / cm 2 or less.
  • the electrical storage element which concerns on one Embodiment of this invention has a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte.
  • a secondary battery will be described as an example of a power storage element.
  • the positive electrode and the negative electrode usually form an electrode body that is alternately superposed by stacking or winding via a separator.
  • the electrode body is housed in a case, and the case is filled with the nonaqueous electrolyte.
  • the non-aqueous electrolyte is interposed between the positive electrode and the negative electrode.
  • a known aluminum case that is usually used as a case of a secondary battery can be used.
  • the secondary battery (storage element) the above-described negative electrode for nonaqueous electrolyte storage element is used as the negative electrode.
  • the secondary battery (storage element) includes a negative electrode having a carbonaceous material as a negative electrode, and has a high capacity retention rate.
  • the positive electrode has a positive electrode base material and a positive electrode active material layer disposed on the positive electrode base material directly or via an intermediate layer.
  • the positive electrode intermediate layer may be the same as the negative electrode intermediate layer described above.
  • the positive electrode base material has conductivity.
  • a metal such as aluminum, titanium, tantalum, stainless steel, or an alloy thereof is used.
  • aluminum and aluminum alloys are preferable from the balance of potential resistance, high conductivity and cost.
  • foil, a vapor deposition film, etc. are mentioned as a formation form of a positive electrode base material, and foil is preferable from the surface of cost. That is, an aluminum foil is preferable as the positive electrode base material.
  • Examples of aluminum or aluminum alloy include A1085P and A3003P defined in JIS-H-4000 (2014).
  • the positive electrode active material layer is formed from a positive electrode active material layer forming material containing a positive electrode active material. Moreover, the positive electrode active material layer forming material which forms a positive electrode active material layer contains arbitrary components, such as a electrically conductive agent, a binder (binder), a thickener, and a filler as needed. These optional components can be the same as those of the negative electrode described above.
  • Examples of the positive electrode active material include composite oxides represented by Li x MO y (M represents at least one transition metal) (Li x CoO 2 having a layered ⁇ -NaFeO 2 type crystal structure, Li x NiO). 2 , Li x MnO 2 , Li x Ni ⁇ Co (1- ⁇ ) O 2 , Li x Ni ⁇ Mn ⁇ Co (1- ⁇ - ⁇ ) O 2, etc.
  • Li x Mn 2 O 4 having a spinel crystal structure Li x Ni ⁇ Mn (2- ⁇ ) O 4 ), (Me represents at least one transition metal, and X represents, for example, P, Si, B, V, etc.) (LiFePO 4 , LiMnPO 4 , LiNiPO 4 , LiCoPO 4 , Li 3 V 2 (PO 4 ) 3 , Li 2 MnSiO 4 , Li 2 CoPO 4 F, etc.).
  • the elements or polyanions in these compounds may be partially substituted with other elements or anion species.
  • one kind of these compounds may be used alone, or two or more kinds may be mixed and used.
  • the negative electrode provided in the secondary battery (storage element) is as described above.
  • the material of the separator for example, a woven fabric, a nonwoven fabric, a porous resin film, or the like is used. Among these, a porous resin film is preferable from the viewpoint of strength.
  • the main component of the separator is preferably a polyolefin such as polyethylene or polypropylene from the viewpoint of strength, and is preferably polyimide or aramid from the viewpoint of resistance to oxidative degradation. These resins may be combined.
  • the density of the porous resin is preferably 0.65 g / cm 3 or less, and more preferably 0.55 g / cm 3 or less.
  • the surface roughness of the negative electrode active material layer is 0.4 ⁇ m or less, even when the density of the porous resin of the separator is low, the separator is hardly damaged, and a slight voltage drop due to the damage of the separator occurs. Hard to do.
  • the lower limit of the density of the porous resin is preferably 0.25 g / cm 3 .
  • Non-aqueous solvent As said non-aqueous solvent, the well-known non-aqueous solvent normally used as a non-aqueous solvent of the general non-aqueous electrolyte for electrical storage elements can be used.
  • the non-aqueous solvent include cyclic carbonate, chain carbonate, ester, ether, amide, sulfone, lactone, and nitrile. Among these, it is preferable to use at least cyclic carbonate or chain carbonate, and it is more preferable to use cyclic carbonate and chain carbonate in combination.
  • the volume ratio of the cyclic carbonate to the chain carbonate is not particularly limited, but is, for example, 5:95 or more and 50:50 or less. Is preferred.
  • cyclic carbonate examples include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), chloroethylene carbonate, fluoroethylene carbonate (FEC), and difluoroethylene.
  • EC ethylene carbonate
  • PC propylene carbonate
  • BC butylene carbonate
  • VEC vinylene carbonate
  • FEC fluoroethylene carbonate
  • difluoroethylene examples include carbonate (DFEC), styrene carbonate, catechol carbonate, 1-phenyl vinylene carbonate, 1,2-diphenyl vinylene carbonate, and among these, EC is preferable.
  • chain carbonate examples include diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diphenyl carbonate.
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • EMC ethyl methyl carbonate
  • diphenyl carbonate examples include diphenyl carbonate.
  • EMC is preferable.
  • electrolyte salt As said electrolyte salt, the well-known electrolyte salt normally used as an electrolyte salt of the general nonaqueous electrolyte for electrical storage elements can be used.
  • the electrolyte salt include lithium salt, sodium salt, potassium salt, magnesium salt, onium salt, and the like, and lithium salt is preferable.
  • lithium salt examples include inorganic lithium salts such as LiPF 6 , LiPO 2 F 2 , LiBF 4 , LiClO 4 , LiN (SO 2 F) 2 , LiSO 3 CF 3 , LiN (SO 2 CF 3 ) 2 , LiN (SO Fluorohydrocarbon groups such as 2 C 2 F 5 ) 2 , LiN (SO 2 CF 3 ) (SO 2 C 4 F 9 ), LiC (SO 2 CF 3 ) 3 , LiC (SO 2 C 2 F 5 ) 3
  • inorganic lithium salts are preferable, and LiPF 6 is more preferable.
  • the upper limit is not particularly limited, but is preferably 2.5M, more preferably 2M, and even more preferably 1.5M.
  • the secondary battery (storage element) can be produced by a known method except that the nonaqueous electrolyte storage element negative electrode is used as the negative electrode.
  • the manufacturing method includes, for example, a step of housing a positive electrode and a negative electrode (electrode body) in a case, and a step of injecting the nonaqueous electrolyte into the case.
  • the present invention is not limited to the above-described embodiment, and can be implemented in a mode in which various changes and improvements are made in addition to the above-described mode.
  • an intermediate layer may be provided in the positive electrode or the negative electrode.
  • the description has been made mainly on the case where the power storage element is a secondary battery, but other power storage elements may be used. Examples of other power storage elements include capacitors (electric double layer capacitors, lithium ion capacitors), primary batteries, and the like.
  • FIG. 1 shows a schematic diagram of a rectangular secondary battery 1 which is an embodiment of a power storage device according to the present invention.
  • the inside of the container is seen through.
  • an electrode body 2 is accommodated in a battery container 3.
  • the electrode body 2 is formed by winding a positive electrode including a positive electrode active material and a negative electrode including a negative electrode active material via a separator.
  • the positive electrode is electrically connected to the positive electrode terminal 4 via the positive electrode lead 4 ′
  • the negative electrode is electrically connected to the negative electrode terminal 5 via the negative electrode lead 5 ′.
  • the nonaqueous electrolyte for electrical storage elements which concerns on one Embodiment of this invention is inject
  • the configuration of the electricity storage device according to the present invention is not particularly limited, and examples thereof include a cylindrical battery, a square battery (rectangular battery), a flat battery, and the like.
  • the present invention can also be realized as a power storage device including a plurality of the above power storage elements.
  • a power storage device is shown in FIG. In FIG. 2, the power storage device 30 includes a plurality of power storage units 20. Each power storage unit 20 includes a plurality of secondary batteries 1.
  • the power storage device 30 can be mounted as a power source for vehicles such as an electric vehicle (EV), a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), and the like.
  • EV electric vehicle
  • HEV hybrid vehicle
  • PHEV plug-in hybrid vehicle
  • surface roughness (arithmetic average roughness (Ra), maximum height (Ry), ten-point average roughness (Rz), average interval of irregularities (Sm), average interval of local peaks (S ) And root mean square roughness (Rms)) were measured by “SPM-9500J2” manufactured by Shimadzu Corporation based on the method described above.
  • the average particle size in the following examples was measured by “SALD-2200” manufactured by Shimadzu Corporation based on the method described above.
  • Example 1 (Production of working electrode) First, as a negative electrode active material, a carbonaceous material (non-graphitizable carbon having an average particle diameter (D50) of 10 ⁇ m), an elastomer SBR as a binder, and CMC as a thickener, in a solid content ratio, 97 parts by mass of a carbonaceous material, 2 parts by mass of a binder, and 1 part by mass of a thickener were kneaded and water was added to prepare a slurry-like negative electrode active material layer forming material.
  • a carbonaceous material non-graphitizable carbon having an average particle diameter (D50) of 10 ⁇ m
  • an elastomer SBR as a binder
  • CMC a thickener
  • the ratio of the total mass of the carbonaceous material, the binder and the thickener in the negative electrode active material layer forming material was defined as the solid content concentration, and water was added so that the solid content concentration was 65%.
  • the negative electrode active material layer forming material was coated on the surface of a copper foil as a negative electrode substrate, and was heat-treated at 120 ° C. and dried. Thereafter, the surface of the coating layer was pressed at a pressure of 2000 N / cm using a roll press apparatus to form a negative electrode active material layer, thereby obtaining a negative electrode. When the surface roughness of this negative electrode active material layer was measured, the arithmetic surface roughness (Ra) was 0.40 ⁇ m. The obtained negative electrode was used as a working electrode in Example 1.
  • Lithium metal was used for the counter electrode.
  • a counter electrode was formed by bonding a lithium metal foil on both sides of a stainless steel mesh base material to which stainless steel terminals were attached, and pressing it.
  • Lithium metal was used for the reference electrode.
  • a reference electrode was prepared by attaching a lithium metal piece to the tip of a stainless steel rod.
  • a nonaqueous electrolyte was prepared by dissolving LiClO 4 as an electrolyte salt at a concentration of 1.0 mol / l in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1.
  • a three-terminal cell was assembled in an Ar box with a dew point of ⁇ 40 ° C. or lower.
  • the three-terminal cell is configured by using an outer package as a glass container and arranging a working electrode, a counter electrode, a reference electrode, and a nonaqueous electrolyte.
  • a glass container is composed of a lid and a housing, and a gold-plated clip having a conductive portion is provided on the lid.
  • Each of the working electrode, the counter electrode, and the reference electrode was fixed by being sandwiched between gold-plated clips provided on the lid.
  • a polypropylene cup into which the non-aqueous electrolyte was poured was installed in the housing of the container.
  • the lid was fitted into the opening of the housing so that the working electrode, the counter electrode, and the reference electrode fixed with the gold-plated clip were immersed in the nonaqueous electrolyte in the cup, and a three-terminal cell was obtained.
  • Comparative Example 1 The negative electrode of Comparative Example 1 was prepared in the same manner as in Example 1, except that when the negative electrode active material layer forming material was prepared, the amount of water added was adjusted so that the solid content concentration of the negative electrode active material layer forming material was 55%. (Working electrode) and a three-terminal cell were obtained. That is, for Example 1 and Comparative Example 1, the surface of the negative electrode active material layer was obtained by making the press pressure of the coating layer (negative electrode active material layer) the same and changing the solid content concentration of the negative electrode active material layer forming material. The roughness was adjusted.
  • Example 2 A negative electrode (working electrode) and a three-terminal cell of Example 2 were obtained in the same manner as in Example 1 except that non-graphitizable carbon having an average particle diameter (D50) of 4 ⁇ m was used as the carbonaceous material.
  • D50 average particle diameter
  • Example 2 in order to adjust the surface roughness of the negative electrode active material layer, the solid content concentration of the negative electrode active material layer forming material was set to 50%, and no pressing was performed.
  • Examples 3 to 5 The negative electrode (working electrode) and the three-terminal cell of Examples 3 to 5 were obtained in the same manner as in Example 1 except that non-graphitizable carbon having an average particle diameter (D50) of 4 ⁇ m was used as the carbonaceous material. It was.
  • the coating layer (negative electrode active material layer) press is not performed, and the solid content concentration of the negative electrode active material layer forming material is 60%, 65%, and 70%, The surface roughness of the negative electrode active material layer was adjusted.
  • Negative electrodes (working electrodes) and three-terminal cells of Reference Examples 1 to 4 were obtained in the same manner as in Example 1 except that graphite (average particle diameter (D50) 5 ⁇ m) was used as the carbon material.
  • the solid content concentration of the negative electrode active material layer forming material was 50, 60, 65, and 70%, and the coating layer (negative electrode active material layer) was not pressed, and the negative electrode active material layer forming material was not pressed. The surface roughness of the material layer was adjusted.
  • the point average roughness (Rz), the average interval of irregularities (Sm), the average interval of local peaks (S) and the root mean square roughness (Rms) were measured. The measurement results are shown in Table 1.
  • charge upper limit voltage is 0.02Vvs.
  • Li / Li + discharge end voltage is 2.0 Vvs.
  • Charging / discharging was performed 3 times as Li / Li + to confirm whether the three-terminal cell was normally produced.
  • a charge / discharge cycle test was performed by the following method to determine the capacity retention rate.
  • the charge / discharge cycle test was also performed in an environment of 25 ° C. Constant current charging was performed at a charging current of 0.5 mA / cm 2 and a final voltage of 0.0 V, and then a 10-minute rest period was provided. Thereafter, a constant current discharge with a discharge current of 2.5 mA / cm 2 and a final voltage of 2.0 V was performed, and then a 10-minute rest period was provided. This charge / discharge was performed 30 cycles. The ratio of the discharge capacity at the 30th cycle to the discharge capacity at the 1st cycle in the charge / discharge cycle test was determined as “capacity maintenance ratio (%)”. The results are shown in Table 1.
  • Example 1 in which the surface roughness of the negative electrode active material layer is 0.4 ⁇ m or less is shown. It can be seen that the three-terminal cell using ⁇ 5 negative electrodes (working electrodes) has a high capacity retention rate. Furthermore, it can be seen that the three-terminal cell using the negative electrodes (working electrodes) of Examples 3 to 5 in which the surface roughness of the negative electrode active material layer is 0.29 ⁇ m or less has a particularly high capacity retention rate.
  • the negative electrode (working electrode) used in Example 1 and Comparative Example 1 was produced with the same pressing pressure on the negative electrode active material layer (coating layer) as described above. That is, the negative electrode (working electrode) of Example 1 and Comparative Example 1 has the ability to collect current between the negative electrode active material layer (coating layer) and the negative electrode substrate (copper foil), and the negative electrode active material layer (coating layer). The density of each is considered to be the same. Therefore, the difference in capacity retention rate of the three-terminal cell using the negative electrode (working electrode) of Example 1 and Comparative Example 1 is the current collecting property between the negative electrode active material layer and the negative electrode substrate, and the density of the negative electrode active material layer. This is considered to be caused by reducing the unevenness of the reaction on the surface of the negative electrode active material layer by regulating the surface roughness of the negative electrode active material layer.
  • the present invention can be applied to electronic devices such as personal computers and communication terminals, non-aqueous electrolyte storage elements such as non-aqueous electric field secondary batteries used as power sources for automobiles, and negative electrodes provided therein.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
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Abstract

L'invention concerne : une électrode négative pour éléments accumulateurs d'électricité à électrolyte non aqueux, qui utilise un matériau carboné en tant que matériau actif d'électrode négative, et qui permet d'améliorer le taux de maintien de capacité d'un élément accumulateur d'électricité à électrolyte non aqueux ; et un élément accumulateur d'électricité à électrolyte non aqueux qui est doté de ladite électrode négative pour éléments accumulateurs d'électricité à électrolyte non aqueux. La présente invention concerne ainsi une électrode négative pour éléments accumulateurs d'électricité à électrolyte non aqueux, qui comporte une couche de matériau actif d'électrode négative comportant un matériau carboné. Selon l'invention, la teneur en matériau carboné par rapport à la couche de matériau actif d'électrode négative est supérieure ou égale à 90 % en masse ; et la rugosité de surface de la couche de matériau actif d'électrode négative est inférieure ou égale à 0,4 µm. La présente invention concerne un élément accumulateur d'électricité à électrolyte non aqueux doté de ladite électrode négative pour éléments accumulateurs d'électricité à électrolyte non aqueux.
PCT/JP2017/033807 2016-09-21 2017-09-20 Électrode négative pour éléments accumulateurs d'électricité à électrolyte non aqueux, et élément accumulateur d'électricité à électrolyte non aqueux WO2018056280A1 (fr)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005108810A (ja) * 2003-09-26 2005-04-21 Samsung Sdi Co Ltd リチウム二次電池
JP2010050476A (ja) * 2003-03-31 2010-03-04 Fuji Heavy Ind Ltd 有機電解質キャパシタ
JP2010098020A (ja) * 2008-10-15 2010-04-30 Hitachi Powdered Metals Co Ltd リチウムイオンキャパシターの負極被膜及び電極被膜形成用塗料組成物
JP2014011070A (ja) * 2012-06-29 2014-01-20 Toyota Motor Corp 非水電解質二次電池
JP2014116155A (ja) * 2012-12-07 2014-06-26 Hitachi Chemical Co Ltd リチウムイオン二次電池用負極材、リチウムイオン二次電池用負極、及びリチウムイオン二次電池、並びにリチウムイオン二次電池用負極材の製造方法
JP2016006763A (ja) * 2014-05-28 2016-01-14 株式会社Ｇｓユアサ 蓄電素子
JP2016181409A (ja) * 2015-03-24 2016-10-13 株式会社Ｇｓユアサ 蓄電素子

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010050476A (ja) * 2003-03-31 2010-03-04 Fuji Heavy Ind Ltd 有機電解質キャパシタ
JP2005108810A (ja) * 2003-09-26 2005-04-21 Samsung Sdi Co Ltd リチウム二次電池
JP2010098020A (ja) * 2008-10-15 2010-04-30 Hitachi Powdered Metals Co Ltd リチウムイオンキャパシターの負極被膜及び電極被膜形成用塗料組成物
JP2014011070A (ja) * 2012-06-29 2014-01-20 Toyota Motor Corp 非水電解質二次電池
JP2014116155A (ja) * 2012-12-07 2014-06-26 Hitachi Chemical Co Ltd リチウムイオン二次電池用負極材、リチウムイオン二次電池用負極、及びリチウムイオン二次電池、並びにリチウムイオン二次電池用負極材の製造方法
JP2016006763A (ja) * 2014-05-28 2016-01-14 株式会社Ｇｓユアサ 蓄電素子
JP2016181409A (ja) * 2015-03-24 2016-10-13 株式会社Ｇｓユアサ 蓄電素子

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