WO2019171436A1 - Dispositif electrochimique - Google Patents

Dispositif electrochimique Download PDF

Info

Publication number
WO2019171436A1
WO2019171436A1 PCT/JP2018/008376 JP2018008376W WO2019171436A1 WO 2019171436 A1 WO2019171436 A1 WO 2019171436A1 JP 2018008376 W JP2018008376 W JP 2018008376W WO 2019171436 A1 WO2019171436 A1 WO 2019171436A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
peak
positive electrode
negative electrode
binding energy
Prior art date
Application number
PCT/JP2018/008376
Other languages
English (en)
Japanese (ja)
Inventor
馨 今野
Original Assignee
日立化成株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日立化成株式会社 filed Critical 日立化成株式会社
Priority to JP2020504498A priority Critical patent/JPWO2019171436A1/ja
Priority to PCT/JP2018/008376 priority patent/WO2019171436A1/fr
Publication of WO2019171436A1 publication Critical patent/WO2019171436A1/fr

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to an electrochemical device.
  • Patent Document 1 discloses a non-aqueous electrolyte battery electrolyte containing a specific siloxane compound in order to improve cycle characteristics and internal resistance characteristics.
  • one of the characteristics required for electrochemical devices is low temperature input characteristics.
  • the charge capacity of electrochemical devices at low temperatures eg, 0 ° C. or lower
  • the charge capacity at normal temperatures eg, 25 ° C.
  • the reduction in charge capacity is suppressed as much as possible. That is, it is required to have excellent low temperature input characteristics.
  • an object of the present invention is to provide an electrochemical device having excellent low-temperature input characteristics and reduced resistance.
  • a peak derived from 2p electrons of a silicon atom present in a bond energy range of 96 eV or more and less than 108 eV and a nitrogen atom present in a bond energy range of 393 eV or more and less than 407 eV are obtained.
  • An electrochemical device comprising an electrode exhibiting a peak derived from 1s electrons.
  • the positive electrode is preferably a peak derived from the 1s electron of a nitrogen atom, preferably a peak existing in the range of a binding energy of 393 eV or more and less than 401 eV, and a bond of 401 eV or more and less than 407 eV. At least one of the peaks existing in the energy range is shown.
  • the ratio of the sum of the peak areas existing in the range of the binding energy of 393 eV or more and less than 401 eV to the sum of the peak areas existing in the range of the binding energy of 401 eV or more and less than 407 eV is preferably 1.0. It is 10.0 or less.
  • the negative electrode is preferably a peak derived from a 1s electron of a nitrogen atom, preferably a peak existing in the range of a binding energy of 393 eV or more and less than 401 eV, and a bond of 401 eV or more and less than 407 eV. At least one of the peaks existing in the energy range is shown.
  • the ratio of the sum of the peak areas existing in the range of the binding energy of 393 eV or more and less than 401 eV to the sum of the peak areas existing in the range of the bond energy of 401 eV or more and less than 407 eV is preferably 2.0 or more. 10.0 or less.
  • the above electrode contains an electrode active material, and preferably a film containing silicon atoms and nitrogen atoms is formed on the surface of the electrode active material.
  • the electrochemical device is preferably a non-aqueous electrolyte secondary battery or a capacitor.
  • an electrochemical device having excellent low-temperature input characteristics and reduced resistance can be provided.
  • FIG. (A) and (c) are spectra derived from 2p electrons of silicon atoms in the positive electrode of Example 1 and Comparative Example 1, respectively, and (b) and (d) are nitrogen in the positive electrode of Example 1 and Comparative Example 1, respectively. It is a spectrum derived from 1s electrons of atoms.
  • (A) and (c) are spectra derived from 2p electrons of silicon atoms in the negative electrode of Example 1 and Comparative Example 1, respectively, and (b) and (d) are nitrogen in the negative electrode of Example 1 and Comparative Example 1, respectively. It is a spectrum derived from 1s electrons of atoms. It is a graph which shows the evaluation result of resistance of Example 1 and Comparative Example 1.
  • (A), (c) and (e) are spectra derived from 2p electrons of silicon atoms in the positive electrodes of Example 2, Comparative Example 2 and Comparative Example 3, respectively,
  • (b) and (f) are It is the spectrum derived from the 1s electron of the nitrogen atom in the positive electrode of Example 2, Comparative example 2, and Comparative example 3, respectively.
  • (A), (c) and (e) are spectra derived from 2p electrons of silicon atoms in the negative electrodes of Example 2, Comparative Example 2 and Comparative Example 3, respectively, and (b), (d) and (f) are It is the spectrum derived from the 1s electron of the nitrogen atom in the negative electrode of Example 2, Comparative example 2, and Comparative example 3, respectively.
  • 6 is a graph showing the evaluation results of resistance in Example 2 and Comparative Examples 2 to 3.
  • 4 is a graph showing evaluation results of cycle characteristics of Example 2 and Comparative Examples 2 to 3.
  • (A) and (c) are TEM observation image results of the positive electrode in Example 1 and Comparative Example 1, respectively.
  • (B) and (d) are Si by EDX measurement in the fields of (a) and (c), respectively. It is an image result of mapping.
  • FIG. 1 is a perspective view showing an electrochemical device according to an embodiment.
  • the electrochemical device is a non-aqueous electrolyte secondary battery.
  • the nonaqueous electrolyte secondary battery 1 includes an electrode group 2 composed of a positive electrode, a negative electrode, and a separator, and a bag-shaped battery exterior body 3 that houses the electrode group 2.
  • a positive electrode current collecting tab 4 and a negative electrode current collecting tab 5 are provided on the positive electrode and the negative electrode, respectively.
  • the positive electrode current collecting tab 4 and the negative electrode current collecting tab 5 protrude from the inside of the battery outer package 3 to the outside so that the positive electrode and the negative electrode can be electrically connected to the outside of the nonaqueous electrolyte secondary battery 1, respectively. .
  • the battery outer package 3 is filled with an electrolytic solution (not shown).
  • the non-aqueous electrolyte secondary battery 1 may be a battery (coin type, cylindrical type, laminated type, etc.) having a shape other than the so-called “laminate type” as described above.
  • the battery outer package 3 may be a container formed of a laminate film, for example.
  • the laminate film may be a laminate film in which a resin film such as a polyethylene terephthalate (PET) film, a metal foil such as aluminum, copper, and stainless steel, and a sealant layer such as polypropylene are laminated in this order.
  • PET polyethylene terephthalate
  • metal foil such as aluminum, copper, and stainless steel
  • sealant layer such as polypropylene
  • FIG. 2 is an exploded perspective view showing an embodiment of the electrode group 2 in the nonaqueous electrolyte secondary battery 1 shown in FIG.
  • the electrode group 2 includes a positive electrode 6, a separator 7, and a negative electrode 8 in this order.
  • the positive electrode 6 and the negative electrode 8 are arranged so that the surfaces on the positive electrode mixture layer 10 side and the negative electrode mixture layer 12 side face the separator 7, respectively.
  • the separator 7 is particularly limited as long as it electrically insulates between the positive electrode 6 and the negative electrode 8 and allows ions to pass therethrough and has resistance to oxidation on the positive electrode 6 side and reduction on the negative electrode 8 side.
  • Examples of the material (material) of the separator 7 include resins and inorganic substances.
  • the separator 7 is preferably a porous sheet or a non-woven fabric formed of a polyolefin such as polyethylene or polypropylene from the viewpoint of being stable with respect to the electrolytic solution and having excellent liquid retention.
  • the separator 7 may be a separator in which a fibrous or particulate inorganic substance is adhered to a thin film substrate such as a nonwoven fabric, a woven fabric, or a microporous film.
  • the electrolytic solution contains an electrolyte salt, a non-aqueous solvent, and an additive.
  • the electrolyte salt may be a lithium salt, for example.
  • the lithium salt include LiPF 6 , LiBF 4 , LiFSI (lithium bisfluorosulfonylimide), LiTFSI (lithium bistrifluoromethanesulfonylimide), LiClO 4 , LiB (C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3. It may be at least one selected from the group consisting of SO 3 , LiN (SO 2 F) 2 , LiN (SO 2 CF 3 ) 2 , and LiN (SO 2 CF 2 CF 3 ) 2 .
  • the lithium salt preferably contains LiPF 6 from the viewpoint of further excellent solubility in a solvent, charge / discharge characteristics of a secondary battery, output characteristics, low temperature input characteristics, and the like.
  • the concentration of the electrolyte salt is preferably 0.5 mol / L or more, more preferably 0.7 mol / L or more, and still more preferably 0.8, based on the total amount of the nonaqueous solvent. It is 8 mol / L or more, preferably 1.5 mol / L or less, more preferably 1.3 mol / L or less, and further preferably 1.2 mol / L or less.
  • Nonaqueous solvents include, for example, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ⁇ -butyl lactone, acetonitrile, 1,2-dimethoxyethane, dimethoxymethane, tetrahydrofuran, dioxolane, methylene chloride, methyl acetate, etc. It may be.
  • the non-aqueous solvent may be one kind of these or a mixture of two or more kinds, preferably a mixture of two or more kinds.
  • the additive may be, for example, nitrogen, sulfur, or a heterocyclic compound containing nitrogen and sulfur, a cyclic carboxylic acid ester, a fluorine-containing cyclic carbonate, or other compounds having an unsaturated bond in the molecule.
  • the positive electrode 6 includes a positive electrode current collector 9 and a positive electrode mixture layer 10 provided on the positive electrode current collector 9.
  • the positive electrode current collector 9 is provided with a positive electrode current collector tab 4.
  • the positive electrode current collector 9 is made of, for example, aluminum, titanium, stainless steel, nickel, baked carbon, conductive polymer, conductive glass, or the like.
  • the positive electrode current collector 9 may have a surface such as aluminum or copper that has been treated with carbon, nickel, titanium, silver, or the like for the purpose of improving adhesiveness, conductivity, and oxidation resistance.
  • the thickness of the positive electrode current collector 9 is, for example, 1 to 50 ⁇ m from the viewpoint of electrode strength and energy density.
  • the positive electrode mixture layer 10 contains a positive electrode active material, a conductive agent, and a binder.
  • the thickness of the positive electrode mixture layer 10 is, for example, 20 to 200 ⁇ m.
  • the positive electrode active material may be lithium oxide, for example.
  • the content of the positive electrode active material may be 80% by mass or more, 85% by mass or more, and 99% by mass or less based on the total amount of the positive electrode mixture layer.
  • the conductive agent may be a carbon black such as acetylene black or ketjen black, a carbon material such as graphite, graphene or carbon nanotube.
  • the content of the conductive agent may be, for example, 0.01% by mass or more, 0.1% by mass or more, or 1% by mass or more based on the total amount of the positive electrode mixture layer, and is 50% by mass or less, 30% by mass. Or 15% by mass or less.
  • binder examples include resins such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, and nitrocellulose; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluorine rubber Rubber such as isoprene rubber, butadiene rubber, ethylene-propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / Thermoplastic elastomers such as ethylene copolymers, styrene / isoprene / styrene block copolymers or hydrogenated products thereof; syndiotactic-1, 2-polybutadiene, polyvinyl acetate, ethylene /
  • the content of the binder may be, for example, 0.1% by mass or more, 1% by mass or more, or 1.5% by mass or more based on the total amount of the positive electrode mixture layer, and is 30% by mass or less, 20% by mass. % Or less, or 10 mass% or less.
  • the negative electrode 8 includes a negative electrode current collector 11 and a negative electrode mixture layer 12 provided on the negative electrode current collector 11.
  • the negative electrode current collector 11 is provided with a negative electrode current collector tab 5.
  • the negative electrode current collector 11 is made of copper, stainless steel, nickel, aluminum, titanium, baked carbon, conductive polymer, conductive glass, aluminum-cadmium alloy, or the like.
  • the negative electrode current collector 11 may be one in which the surface of copper, aluminum or the like is treated with carbon, nickel, titanium, silver or the like for the purpose of improving adhesiveness, conductivity, and reduction resistance.
  • the thickness of the negative electrode current collector 11 is, for example, 1 to 50 ⁇ m from the viewpoint of electrode strength and energy density.
  • the negative electrode mixture layer 12 contains, for example, a negative electrode active material, a binder, and a thickener.
  • the negative electrode active material is not particularly limited as long as it is a material capable of occluding and releasing lithium ions.
  • Examples of the negative electrode active material include carbon materials, metal composite oxides, oxides or nitrides of Group 4 elements such as tin, germanium, and silicon, simple substances of lithium, lithium alloys such as lithium aluminum alloys, silicon and tin Examples thereof include a material containing at least one element selected from the group consisting of metals and metals capable of forming an alloy with lithium.
  • the negative electrode active material is preferably at least one selected from the group consisting of a carbon material and a metal composite oxide from the viewpoint of safety.
  • the negative electrode active material may be one of these alone or a mixture of two or more.
  • the shape of the negative electrode active material may be, for example, a particulate shape.
  • carbon materials examples include amorphous carbon materials, natural graphite, composite carbon materials in which a film of amorphous carbon material is formed on natural graphite, artificial graphite (resin raw materials such as epoxy resins and phenol resins, or petroleum, coal, etc. And the like obtained by firing a pitch-based raw material obtained from the above.
  • the metal composite oxide preferably contains one or both of titanium and lithium, and more preferably contains lithium.
  • the negative electrode active materials carbon materials have high conductivity and are particularly excellent in low temperature characteristics and cycle stability.
  • graphite is preferable from the viewpoint of increasing the capacity.
  • the carbon network plane interlayer (d002) in the X-ray wide angle diffraction method is preferably less than 0.34 nm, more preferably 0.3354 nm or more and 0.337 nm or less.
  • a carbon material that satisfies such conditions may be referred to as pseudo-anisotropic carbon.
  • the material containing at least one element selected from the group consisting of silicon and tin may be a compound containing at least one element selected from the group consisting of silicon or tin alone, silicon and tin.
  • the compound may be an alloy containing at least one element selected from the group consisting of silicon and tin.
  • nickel, copper, iron, cobalt, manganese, zinc, indium, silver An alloy containing at least one selected from the group consisting of titanium, germanium, bismuth, antimony and chromium.
  • the compound containing at least one element selected from the group consisting of silicon and tin may be an oxide, a nitride, or a carbide.
  • silicon oxide such as SiO, SiO 2 , LiSiO, etc.
  • silicon nitride such as Si 3 N 4 and Si 2 N 2 O
  • silicon carbide such as SiC
  • tin oxide such as SnO, SnO 2 and LiSnO.
  • the negative electrode mixture layer 12 preferably contains a carbon material, more preferably graphite, and more preferably carbon material, silicon, and silicon as the negative electrode active material. It includes a mixture with a material containing at least one element selected from the group consisting of tin, and particularly preferably includes a mixture of graphite and silicon oxide.
  • the content of the material (silicon oxide) containing at least one element selected from the group consisting of silicon and tin in the mixture is 1% by mass or more, or 3% by mass or more based on the total amount of the mixture, It may be 30% by mass or less.
  • the content of the negative electrode active material may be 80% by mass or more, 85% by mass or more, and 99% by mass or less based on the total amount of the negative electrode mixture layer.
  • the binder and its content may be the same as the binder and its content in the positive electrode mixture layer described above.
  • the negative electrode mixture layer 12 may further contain a thickener in order to adjust the viscosity.
  • the thickener is not particularly limited, but may be carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof.
  • the thickener may be one of these alone or a mixture of two or more.
  • the content of the thickener may be 0.1% by mass or more, preferably 0.2% by mass or more, based on the total amount of the negative electrode mixture layer. More preferably, it is 0.5% by mass or more.
  • the content of the thickener may be 5% by mass or less, preferably 3% by mass or less, more preferably 2 from the viewpoint of suppressing a decrease in battery capacity or an increase in resistance between the negative electrode active materials. It is below mass%.
  • At least one of the positive electrode 6 and the negative electrode 8 is a peak derived from 2p electrons of silicon atoms (hereinafter also referred to as “Si2p peak”) and a 1s electron of nitrogen atoms in the measurement by X-ray photoelectron spectroscopy (XPS). (Hereinafter also referred to as “N1s peak”).
  • the peak of Si2p exists in the range of the binding energy of 96 eV or more and less than 108 eV.
  • the peak of N1s exists in the binding energy range of 393 eV or more and less than 407 eV.
  • both the positive electrode 6 and the negative electrode 8 exhibit a Si2p peak and a N1s peak.
  • the range of the binding energy where the peak of Si2p exists in the positive electrode 6 and the negative electrode 8 is 96 eV or more and less than 108 eV, preferably 98 eV or more and less than 106 eV, more preferably 99 eV or more and less than 104 eV, and further preferably 100 eV or more and 103 eV. Is less than. Only one Si2p peak may be present in the above-mentioned range of binding energy, or two or more peaks may be present, for example, near 102 eV and 104 eV.
  • the range of the binding energy where the N1s peak exists is 393 eV or more and less than 407 eV, preferably 394 eV or more and less than 405 eV, more preferably 395 eV or more and less than 404 eV. There may be only one N1s peak in the above-mentioned range of binding energy, or two or more peaks.
  • the positive electrode 6 and the negative electrode 8 may show at least one of a peak existing in a range of binding energy of 393 eV or more and less than 401 eV and a peak existing in a range of binding energy of 401 eV or more and less than 407 eV as a peak of N1s, At least one N1s peak (first N1s peak) in a binding energy range of 393 eV to less than 401 eV, and at least one N1s peak (second N1s peak in a binding energy range of 401 eV to less than 407 eV). May be shown).
  • the range of the binding energy where the first N1s peak exists is preferably 394 eV or more and less than 401 eV, and more preferably 395 eV or more and less than 401 eV.
  • the range of the binding energy in which the second N1s peak exists is preferably 401 eV or more and less than 406 eV, more preferably 401 eV or more and less than 404 eV.
  • one or more first N1s peaks may exist near 397 eV or 400 eV
  • one or more second N1s peaks may exist near 402 eV or 403 eV, for example.
  • the Si2p peak and the N1s peak in the positive electrode 6 and the negative electrode 8 are, for example, a spectrum derived from 2p electrons of a silicon atom measured using an X-ray photoelectron spectroscopy system (for example, “K-Alpha” from Thermo Scientific) and It can be analyzed from the spectrum derived from the 1s electron of the nitrogen atom.
  • the measurement conditions for example, the measurement can be performed under the conditions that the X-ray source is Al K ⁇ ray, the voltage is 12 kV, the current value is 6 mA, and the spot size is 200 to 400 ⁇ m.
  • the degree of vacuum in the sample evaluation chamber before measurement can be measured at 5.0 ⁇ 10 ⁇ 8 to 1.0 ⁇ 10 ⁇ 9 mBar.
  • the peak derived from LiF in the spectrum derived from 1s electrons of fluorine (F1s spectrum) may be adjusted to 685 eV.
  • the XPS spectrum for analyzing the Si2p peak and the N1s peak is measured as follows.
  • the electrochemical device that was charged and discharged was completely discharged, and the non-aqueous electrolyte secondary battery (electrochemical device) 1 was placed in a glove box under an argon atmosphere (oxygen concentration of less than 1 ppm, dew point of less than -70 ° C). It disassembles and takes out the positive electrode 6 or the negative electrode 8.
  • the positive electrode 6 or the negative electrode 8 is washed with a nonaqueous solvent (for example, dimethyl carbonate) and then dried.
  • a nonaqueous solvent for example, dimethyl carbonate
  • the Si2p peak and the N1s peak shown by the positive electrode 6 and the negative electrode 8 are obtained because the positive electrode 6 and the negative electrode 8 contain silicon atoms and nitrogen atoms on their surfaces, respectively.
  • the Si2p peak and the N1s peak shown by the positive electrode 6 and the negative electrode 8 are obtained because, in an embodiment, films containing silicon atoms and nitrogen atoms are formed on the surfaces of the positive electrode active material and the negative electrode active material, respectively. It is done.
  • This film containing silicon atoms and nitrogen atoms may contain, for example, a compound containing silicon atoms and not containing nitrogen atoms in the same molecule and a compound containing nitrogen atoms and not containing silicon atoms in the same molecule, Alternatively, a compound containing a silicon atom and a nitrogen atom may be contained in the same molecule, and preferably a compound containing a silicon atom and a nitrogen atom is contained in the same molecule.
  • This film may be formed on at least a part of the positive electrode active material and the negative electrode active material. Preferably, the portion where the positive electrode active material and the negative electrode active material are exposed on the surfaces of the positive electrode 6 and the negative electrode 8 ( It may be formed on a part or all of the part in contact with the electrolyte.
  • FIB focused ion beam
  • TEM / EDX energy dispersive X-ray analysis
  • a focused ion beam / electron beam processing observation apparatus (nanoDUE'T NB5000, manufactured by Hitachi High-Technologies Corporation) can be used.
  • TEM / EDX analysis scanning transmission with a spherical aberration correction function is used.
  • An electron microscope for example, JEM-ARM200F (manufactured by JEOL Ltd.) / JED-2300T (manufactured by JEOL Ltd.) etc.
  • JEM-ARM200F manufactured by JEOL Ltd.
  • JED-2300T manufactured by JEOL Ltd.
  • the silicon atom and the nitrogen atom contained in the film formed on the surface of the positive electrode 6 (positive electrode active material) or the negative electrode 8 (negative electrode active material) are derived from the compound represented by the following formula (1).
  • R 1 to R 3 each independently represents an alkyl group or a fluorine atom
  • R 4 represents an alkylene group
  • R 5 represents an organic group containing a nitrogen atom.
  • the compound represented by the formula (1) contains only one silicon atom in one molecule. That is, in one embodiment, the organic group represented by R 5 does not contain a silicon atom.
  • the alkyl group represented by R 1 to R 3 may have 1 or more carbon atoms and 3 or less carbon atoms.
  • R 1 to R 3 may be a methyl group, an ethyl group, or a propyl group, and may be linear or branched. At least one of R 1 to R 3 is preferably a fluorine atom.
  • Carbon number of the alkylene group represented by R 4 may be 1 or more, 2 or less, or 5 or less or 4 or less.
  • the alkylene group represented by R 4 may be a methylene group, an ethylene group, a propylene group, a butylene group, or a pentylene group, and may be linear or branched.
  • R 5 may be a group represented by the following formula (2) in one embodiment from the viewpoint of further improving the low temperature input characteristics of the electrochemical device.
  • R 6 and R 7 each independently represent a hydrogen atom or an alkyl group.
  • the alkyl group represented by R 6 or R 7 may be the same as the alkyl group represented by R 1 to R 3 described above. * Indicates a bond.
  • the non-aqueous electrolyte secondary battery 1 Resistance is significantly reduced, and input characteristics at low temperatures are remarkably improved.
  • a decrease in cycle characteristics caused by the electrolytic solution or the decomposition product of the electrolyte salt deposited on the positive electrode 6 or the negative electrode 8 is suppressed.
  • membrane containing a silicon atom is formed in the surface of the negative electrode 8 (negative electrode active material), it is thought that the nonaqueous electrolyte secondary battery 1 is stabilized more physically and electrochemically. It is done.
  • the area of each peak can be calculated by the following method.
  • a baseline is drawn using a Shirley method in a region where the binding energy is 96 eV or more and less than 108 eV.
  • a baseline is drawn using the Shirley method in a region where the binding energy is 393 eV or more and less than 407 eV.
  • peaks existing in these ranges are separated using a Gaussian function, and the area of the portion surrounded by the baseline is obtained. When there are a plurality of peaks, the total area of each peak is obtained.
  • the positive electrode 6 exhibits at least one N1s peak in a binding energy range of 393 eV or more and less than 401 eV and further shows at least one N1s peak in a binding energy range of 401 eV or more and less than 407 eV
  • the positive electrode 6 has a peak of 393 eV or more and less than 401 eV.
  • the ratio RN 1 of N1 for N2 is preferably 1.0 or more, more preferably 2.0 or more.
  • RN 1 is not particularly limited, it is, for example, 10.0 or less, 8.0 or less, 5.0 or less, or 3.0 or less. That is, RN 1 is 1.0 or more and 10.0 or less, 1.0 or more and 8.0 or less, 1.0 or more and 5.0 or less, 1.0 or more and 3.0 or less, and 2.0 or more and 10.0 or less. 2.0 or more and 8.0 or less, 2.0 or more and 5.0 or less, or 2.0 or more and 3.0 or less.
  • RN 1 When RN 1 is 1.0 or more, silicon atoms and nitrogen atoms derived from a compound having a structure by interaction with a carrier such as Li ion are included as a film on the surface of positive electrode 6 (positive electrode active material). It is considered that the ionic conductivity is improved. When RN 1 is 2.0 or more, the silicon atom and the nitrogen atom (or a compound derived from them) contained in the film formed on the surface of the (positive electrode active material) are further stabilized, thereby causing resistance. It is considered that the low temperature input characteristic and the cycle characteristic are further improved.
  • the negative electrode 8 shows at least one N1s peak in the range of the binding energy of 393 eV or more and less than 401 eV, and further shows at least one N1s peak in the range of the binding energy of 401 eV or more and less than 407 eV, it is 393 eV or more and less than 401 eV
  • the ratio RN 2 of N3 for N4 is preferably 1.0 or more, more preferably 2.0 or more, and further preferably 3.0 or more.
  • RN 2 is not particularly limited, it is, for example, 10.0 or less, 9.0 or less, 8.5 or less, 7.0 or less, or 5.0 or less. That, RN 2 is 1.0 to 10.0, 1.0 to 9.0, 1.0 to 8.5, 1.0 to 7.0, 1.0 to 5.0 2.0 to 10.0, 2.0 to 9.0, 2.0 to 8.5, 2.0 to 7.0, 2.0 to 5.0, 3.0 or more It may be 10.0 or less, 3.0 or more and 9.0 or less, 3.0 or more and 8.5 or less, 3.0 or more and 7.0 or less, or 3.0 or more and 5.0 or less.
  • RN 2 When RN 2 is 1.0 or more, silicon atoms and nitrogen atoms derived from a compound having a structure by interaction with a carrier such as Li ion are included as a film on the surface of negative electrode 8 (negative electrode active material). It is considered that the ionic conductivity is improved. When RN 2 is 2.0 or more, silicon atoms and nitrogen atoms (or compounds derived from them) contained in the film formed on the surface of the negative electrode 8 (negative electrode active material) are further stabilized. It is considered that the resistance is further reduced and the low temperature input characteristics and the cycle characteristics are further improved.
  • the manufacturing method of the nonaqueous electrolyte secondary battery 1 includes a first step of obtaining the positive electrode 6, a second step of obtaining the negative electrode 8, a third step of housing the electrode group 2 in the battery outer package 3, And a fourth step of injecting the electrolytic solution into the battery outer package 3.
  • the positive electrode mixture is treated with a doctor blade method,
  • the positive electrode 6 is obtained by coating on the positive electrode current collector 9 by dipping method, spraying method or the like, and then volatilizing the dispersion medium.
  • a compression molding step using a roll press may be provided as necessary.
  • the positive electrode mixture layer 10 may be formed as a positive electrode mixture layer having a multilayer structure by performing the above-described steps from application of the positive electrode mixture to volatilization of the dispersion medium a plurality of times.
  • the dispersion medium may be water, 1-methyl-2-pyrrolidone (hereinafter also referred to as NMP), and the like.
  • the second step may be the same as the first step described above, and the method of forming the negative electrode mixture layer 12 on the negative electrode current collector 11 may be the same method as the first step described above. .
  • the separator 7 is sandwiched between the produced positive electrode 6 and negative electrode 8, and the electrode group 2 is formed.
  • the electrode group 2 is accommodated in the battery outer package 3.
  • the electrolytic solution is injected into the battery outer package 3.
  • the electrolytic solution can be prepared, for example, by first dissolving the electrolyte salt in a solvent and then dissolving other materials.
  • the compound represented by the above formula (1) is added to the electrolytic solution. That is, the electrolytic solution may contain the compound represented by the formula (1).
  • the content of the compound represented by the formula (1) is preferably 0.001% by mass or more, more preferably 0, based on the total amount of the electrolyte from the viewpoint of further improving the low temperature input characteristics of the electrochemical device. 0.005% by mass or more, and more preferably 0.01% by mass or more. From the same viewpoint, the content of the compound represented by the formula (1) is preferably 10% by mass or less, more preferably 7% by mass or less, and further preferably 5% by mass based on the total amount of the electrolytic solution. % Or less, particularly preferably 3% by mass or less.
  • the electrochemical device may be a capacitor. Similar to the non-aqueous electrolyte secondary battery 1 described above, the capacitor may include an electrode group including a positive electrode, a negative electrode, and a separator, and a bag-shaped battery outer package that houses the electrode group. The details of each component in the capacitor may be the same as those of the non-aqueous electrolyte secondary battery 1.
  • Example 1 Lithium cobaltate (95% by mass) as a positive electrode active material, fibrous graphite (1% by mass) and acetylene black (AB) (1% by mass) as a conductive agent, and a binder (3% by mass) Were added sequentially and mixed.
  • NMP as a dispersion medium was added and kneaded to prepare a slurry-like positive electrode mixture.
  • a predetermined amount of this positive electrode mixture was uniformly and uniformly applied to an aluminum foil having a thickness of 20 ⁇ m as a positive electrode current collector. Then, after volatilizing the dispersion medium, the dispersion medium was compacted to a density of 3.6 g / cm 3 by pressing to obtain a positive electrode.
  • a positive electrode cut into a 13.5 cm 2 square was sandwiched between polyethylene porous sheets (trade names: Hypore (registered trademark), manufactured by Asahi Kasei Co., Ltd., thickness 30 ⁇ m) as a separator, and further, 14.3 cm 2
  • a negative electrode cut into a quadrangular shape was stacked to produce an electrode group.
  • This electrode group was accommodated in a container (battery exterior body) formed of an aluminum laminate film (trade name: aluminum laminate film, manufactured by Dai Nippon Printing Co., Ltd.). Subsequently, 1 mL of electrolyte solution was added in the container, the container was heat-welded, and the lithium ion secondary battery for evaluation was produced.
  • 1% by mass of vinylene carbonate (VC) with respect to the total amount of the mixed solution in a mixed solution of ethylene carbonate, dimethyl carbonate and diethyl carbonate containing 1 mol / L LiPF 6 is represented by the following formula (3).
  • the compound A used was added with 1% by mass based on the total amount of the electrolyte.
  • Example 1 a lithium ion secondary battery was produced in the same manner as in Example 1 except that Compound A was not used.
  • the spectrum by XPS was measured for the positive electrode and the negative electrode by the following method.
  • the charged and discharged lithium ion secondary battery was completely discharged, the battery was disassembled in a glove box under an argon atmosphere (oxygen concentration less than 1 ppm, dew point less than -70 ° C.), and the positive electrode and the negative electrode were taken out. .
  • the positive electrode and the negative electrode were washed with dimethyl carbonate, and then dried by holding in a vacuum atmosphere at 25 ° C.
  • FIG. 3 shows data of each spectrum at the positive electrode
  • FIG. 4 shows data of each spectrum at the negative electrode.
  • (a) and (c) are the Si2p spectra of Example 1 and Comparative Example 1, respectively
  • (b) and (d) are the N1s spectra of Example 1 and Comparative Example 1, respectively. It is.
  • ⁇ Positive electrode> in the spectrum derived from 2p electrons of silicon atoms, a baseline was drawn in the region from 96 eV to 108 eV using the Shirley method. The peaks in the vicinity of 102 eV and 104 eV were separated using a Gaussian function, and the area surrounded by the base line was obtained. Similarly, in the N1s spectrum, a baseline was drawn in the region from 395 eV to 406 eV using the Shirley method. The peak in the vicinity of 400 eV was peak-separated using a Gaussian function, the area surrounded by the base line was determined, and the sum of these areas was defined as N1. Next, the peak in the vicinity of 402 eV was separated using a Gaussian function, the area of the portion surrounded by the baseline was determined, and the sum of these areas was N2.
  • ⁇ Negative electrode> Similar to the positive electrode, a baseline was drawn in the region of 96 eV to 108 eV using the Shirley method in the Si2p spectrum. The peaks in the vicinity of 101 eV and 103 eV were separated using a Gaussian function, and the area of the portion surrounded by the baseline was obtained. Similarly, in the spectrum of N1s, a baseline was drawn using the Shirley method in a region from 393 eV to 407 eV. Peaks in the vicinity of 397 eV and 400 eV in the meantime were separated using a Gaussian function, the area of the portion surrounded by the baseline was determined, and the sum of these areas was N3. Next, the peak in the vicinity of 402 eV was separated using a Gaussian function, the area surrounded by the baseline was determined, and the sum of these areas was defined as N4.
  • Example 1 For positive and negative electrodes of Examples and Comparative Examples, to observe the peak of each element was determined RN 1 (N1 / N2) and RN 2 (N3 / N4). As a result, in Example 1, the peak of the peak and N1s of Si2p observed, RN 1 is 2.8, RN 2 was 3.7. In Comparative Example 1, the Si2p peak and the N1s peak were not observed.
  • the resistances of the lithium ion secondary batteries of Example 1 and Comparative Example 1 were evaluated by AC impedance measurement. Specifically, the prepared lithium ion battery was subjected to constant current charging at a current value of 0.1 C up to an upper limit voltage of 4.2 V in an environment of 25 ° C., and subsequently, constant voltage charging was performed at 4.2 V. The charge termination condition was a current value of 0.01C. These lithium ion secondary batteries were measured in an environment of 25 ° C. using an AC impedance measuring device (1260 type, manufactured by Solartron) in the frequency range of 20 mHz to 200 kHz with an amplitude of 10 mV. The measurement results are shown in FIG.
  • the lithium ion secondary battery of Example 1 including a positive electrode and a negative electrode showing a peak derived from 2p electrons and a peak derived from 1s electrons of a nitrogen atom present in a binding energy range of 393 eV or more and less than 407 eV is as described above. It is clear that the input characteristics at low temperature ( ⁇ 10 ° C.) are better and the impedance (resistance) at 25 ° C.
  • Example 2 A lithium ion secondary battery was produced in the same manner as in Example 1 except that silicon oxide was further added as the negative electrode active material in Example 1 to produce a negative electrode.
  • Example 2 A lithium ion secondary battery was produced in the same manner as in Example 2 except that Compound A was not used in Example 2.
  • Example 2 was the same as Example 2 except that 4-fluoro-1,3-dioxolan-2-one (fluoroethylene carbonate; FEC) was added in place of Compound A in an amount of 1% by mass based on the total amount of the electrolytic solution. Thus, a lithium ion secondary battery was produced.
  • FEC fluoroethylene carbonate
  • Example 2 [Calculation of peak area] From the spectrum obtained by XPS measurement, the peak of each element was observed by the same method as in Example 1 and Comparative Example 1, and the area of each peak was calculated. RN 1 and RN 2 were determined for the positive electrode and negative electrode of each example and comparative example. As a result, in Example 2, the peak of the peak and N1s of Si2p observed, RN 1 is 2.6, RN 2 was 4.3. On the other hand, in Comparative Example 2 and Comparative Example 3, the Si2p peak and the N1s peak were not observed.
  • FIG. 9 shows the relationship between the number of cycles and the relative value of the discharge capacity.
  • the lithium ion secondary battery of Example 2 including a positive electrode and a negative electrode showing a peak derived from 2p electrons and a peak derived from 1s electrons of nitrogen atoms existing in a binding energy range of 393 eV or more and less than 407 eV is as described above.
  • the input characteristics at low temperature were better as compared with the lithium ion secondary battery of Comparative Example 2 provided with a positive electrode and a negative electrode that did not show any peak. Further, as shown in FIG. 9, the lithium ion secondary battery of Example 2 was compared with Comparative Example 2 and further compared with the lithium ion secondary battery of Comparative Example 3 containing 1% by mass of FEC at 25 ° C. It became clear that impedance (resistance) was low. The mechanism for improving this characteristic is not always clear, but a stable and good ion-conducting film is formed on the surface of the positive electrode (positive electrode active material) or the negative electrode (negative electrode active material) as in the case of providing a negative electrode containing graphite. It is considered that the activation energy for the formation of lithium and the desolvation of lithium has decreased.
  • the lithium ion secondary battery of Example 2 had better cycle characteristics than the lithium ion secondary batteries of Comparative Examples 2 to 3.
  • the mechanism for improving the cycle characteristics is not necessarily clear, since a stable film is formed on the positive electrode or the negative electrode, decomposition of the electrolyte near the electrode is suppressed, and further, decomposition of the electrolyte salt (LiPF 6 ) is prevented. It is thought that it was suppressed.
  • a focused ion beam / electron beam processing observation apparatus (nanoDUE'T NB5000, manufactured by Hitachi High-Technologies Corporation) was used for the FIB processing. Thereafter, the thinned positive electrode was observed with a TEM / EDX apparatus.
  • a scanning transmission electron microscope with a spherical aberration correction function (JEM-ARM200F, manufactured by JEOL Ltd./JED-2300T, manufactured by JEOL Ltd.) was used for TEM / EDX observation.
  • Fig. 10 shows the observation image results obtained.
  • the TEM observation image result of the positive electrode of the lithium ion secondary battery described in Example 1 is shown in (a), and the image result of Si mapping by EDX measurement in the visual field is shown in (b). From these results, it was confirmed that silicon atoms were present on the surface of the positive electrode active material 13, and it was confirmed that a film 14 containing at least silicon atoms was formed on the surface of the positive electrode active material.
  • (c) shows the TEM observation image result of the positive electrode of the lithium ion secondary battery described in Comparative Example 1
  • (d) shows the Si mapping image result by EDX measurement in the field of view. From these results, it was confirmed that no film containing silicon atoms was formed on the surface of the positive electrode active material 13 in the positive electrode of Comparative Example 1.
  • non-aqueous electrolyte secondary battery electrochemical device
  • 6 positive electrode
  • 7 separator
  • 8 negative electrode

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)
  • Secondary Cells (AREA)

Abstract

La présente invention concerne, dans un mode de réalisation, un dispositif électrochimique équipé d'une électrode présentant, dans une mesure par spectroscopie photoélectronique à rayons X, un pic présent dans une plage d'énergie de liaison de 96 eV à moins de 108 eV qui provient d'un électron 2p d'atome de silicium, et un pic présent dans une plage d'énergie de liaison de 393 eV à moins de 407 eV qui provient d'un électron 1s d'atome d'azote.
PCT/JP2018/008376 2018-03-05 2018-03-05 Dispositif electrochimique WO2019171436A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2020504498A JPWO2019171436A1 (ja) 2018-03-05 2018-03-05 電気化学デバイス
PCT/JP2018/008376 WO2019171436A1 (fr) 2018-03-05 2018-03-05 Dispositif electrochimique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2018/008376 WO2019171436A1 (fr) 2018-03-05 2018-03-05 Dispositif electrochimique

Publications (1)

Publication Number Publication Date
WO2019171436A1 true WO2019171436A1 (fr) 2019-09-12

Family

ID=67846600

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2018/008376 WO2019171436A1 (fr) 2018-03-05 2018-03-05 Dispositif electrochimique

Country Status (2)

Country Link
JP (1) JPWO2019171436A1 (fr)
WO (1) WO2019171436A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020218020A1 (fr) * 2019-04-26 2020-10-29 株式会社村田製作所 Matériau actif d'électrode négative, électrode négative et batterie secondaire

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002042864A (ja) * 2000-07-28 2002-02-08 Matsushita Electric Ind Co Ltd 非水電解質二次電池
JP2009037842A (ja) * 2007-08-01 2009-02-19 Sony Corp 負極、電池およびそれらの製造方法
WO2017061323A1 (fr) * 2015-10-05 2017-04-13 東レ株式会社 Électrode positive pour batterie secondaire au lithium-ion, particules composites de matière active d'électrode positive/graphène, et leurs procédés de fabrication, et pâte d'électrode positive pour batterie secondaire au lithium-ion

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002042864A (ja) * 2000-07-28 2002-02-08 Matsushita Electric Ind Co Ltd 非水電解質二次電池
JP2009037842A (ja) * 2007-08-01 2009-02-19 Sony Corp 負極、電池およびそれらの製造方法
WO2017061323A1 (fr) * 2015-10-05 2017-04-13 東レ株式会社 Électrode positive pour batterie secondaire au lithium-ion, particules composites de matière active d'électrode positive/graphène, et leurs procédés de fabrication, et pâte d'électrode positive pour batterie secondaire au lithium-ion

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020218020A1 (fr) * 2019-04-26 2020-10-29 株式会社村田製作所 Matériau actif d'électrode négative, électrode négative et batterie secondaire

Also Published As

Publication number Publication date
JPWO2019171436A1 (ja) 2021-03-18

Similar Documents

Publication Publication Date Title
RU2540321C1 (ru) Активный материал отрицательного электрода для электрического устройства
JP3658517B2 (ja) 非水系電解液二次電池
WO2019171436A1 (fr) Dispositif electrochimique
US11444325B2 (en) Electrolytic solution and electrochemical device
KR102561972B1 (ko) 전해액 및 전기화학 디바이스
WO2020116583A1 (fr) Solution électrolytique, et dispositif électrochimique
JP7040594B2 (ja) 電気化学デバイス
CN113396493A (zh) 电解液及电化学器件
JP2020004542A (ja) 負極及び電気化学デバイス
JP7415947B2 (ja) 電解液及び電気化学デバイス
US11411250B2 (en) Electrolytic solution and electrochemical device
US11276862B2 (en) Electrode for secondary battery and secondary battery
WO2018220799A1 (fr) Solution électrolytique, et dispositif électrochimique
WO2020027004A1 (fr) Électrolyte et dispositif électrochimique
JP3555262B2 (ja) 電池用電解質および電池
WO2018220795A1 (fr) Solution électrolytique, et dispositif électrochimique
WO2020027003A1 (fr) Électrolyte et dispositif électrochimique
JP2015201335A (ja) リチウムイオン電池

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18908796

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2020504498

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18908796

Country of ref document: EP

Kind code of ref document: A1