WO2019244936A1 - 正極活物質および電池 - Google Patents
正極活物質および電池 Download PDFInfo
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- WO2019244936A1 WO2019244936A1 PCT/JP2019/024321 JP2019024321W WO2019244936A1 WO 2019244936 A1 WO2019244936 A1 WO 2019244936A1 JP 2019024321 W JP2019024321 W JP 2019024321W WO 2019244936 A1 WO2019244936 A1 WO 2019244936A1
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- C01G51/00—Compounds of cobalt
- C01G51/40—Cobaltates
- C01G51/42—Cobaltates containing alkali metals, e.g. LiCoO2
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- C01—INORGANIC CHEMISTRY
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- C01G51/00—Compounds of cobalt
- C01G51/04—Oxides; Hydroxides
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/74—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by peak-intensities or a ratio thereof only
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- C01—INORGANIC CHEMISTRY
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- C01P2002/00—Crystal-structural characteristics
- C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
- C01P2002/82—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by IR- or Raman-data
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
- C01P2002/85—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by XPS, EDX or EDAX data
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- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
- C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
- C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
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- C—CHEMISTRY; METALLURGY
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- C01P2006/00—Physical properties of inorganic compounds
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- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/40—Electric properties
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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- 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 positive electrode active material and a battery.
- LiCoO 2 lithium cobalt oxide
- Patent Literature 1 discusses a technique for providing lithium cobalt oxide having a certain performance by analyzing the structural change of lithium cobalt oxide by Raman spectrum and predicting cycle life characteristics and charge / discharge characteristics.
- An object of the present invention is to provide a positive electrode active material and a battery that can achieve both charge / discharge cycle characteristics and storage characteristics.
- a first invention includes positive electrode active material particles including a composite oxide having a hexagonal structure, and the composite oxide includes Li, Co, Ni, Fe, Pb, At least one element M1 selected from the group consisting of Mg, Al, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn and Cr; Element M1 is present on the surface of the positive electrode active material particles, and the atomic ratio of the amount of Co on the surface of the positive electrode active material particles to the total amount of at least one element M1 (total amount of at least one element M1 / Co amount) Is 0.6 or more and 1.3 or less, the half-width of the peak of the A 1g vibration mode of the hexagonal structure in the Raman spectrum is 10 cm -1 or more and 17 cm -1 or less, and the hexagonal structure in the Raman spectrum is of a 1g vibration mode of Over click and intensity IA 1 g-H, the peak intensity ratio IA 1g-H
- the "surface of the positive electrode active material particles” refers to a region having a depth of 5 nm or less from the outermost surface of the positive electrode active material particles.
- a second invention is a battery including a positive electrode containing the above-described positive electrode active material, a negative electrode, and an electrolyte.
- FIG. 1 is a cross-sectional view illustrating an example of a configuration of a positive electrode active material according to a first embodiment of the present invention.
- 4 is a graph illustrating an example of a Raman spectrum of the positive electrode active material according to the first embodiment of the present invention. It is an exploded perspective view showing an example of the composition of the nonaqueous electrolyte secondary battery concerning a 2nd embodiment of the present invention.
- FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3. It is a block diagram showing an example of composition of an electronic device concerning a 3rd embodiment of the present invention.
- Embodiments of the present invention will be described in the following order. 1. First Embodiment (Example of Positive Electrode Active Material) 2. Second Embodiment (Example of Laminated Battery) 3. Third embodiment (example of electronic device)
- the present inventors include a composite oxide having a hexagonal structure in order to achieve both cycle characteristics and storage characteristics, and this composite oxide is composed of Li, Co, Ni, At least one element M1 selected from the group consisting of Fe, Pb, Mg, Al, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn and Cr
- the positive electrode active material particles were studied diligently. As a result, they have found that the content and the crystal structure of at least one element M1 on the surface of the positive electrode active material particles are defined.
- the content and the crystal structure are defined as follows.
- (B) The half-width of the peak of the A 1g vibration mode of the hexagonal structure in the Raman spectrum is 10 cm ⁇ 1 to 17 cm ⁇ 1, and the peak intensity IA 1g-H of the A 1g vibration mode of the hexagonal structure in the Raman spectrum.
- the crystal structure on the surface of the positive electrode active material particles is adjusted. Is defined.
- FIG. 1 shows an example of the configuration of the positive electrode active material according to the first embodiment of the present invention.
- the positive electrode active material according to the first embodiment is a positive electrode active material for a so-called non-aqueous electrolyte secondary battery, and includes a powder of surface-coated positive electrode active material particles 100.
- the surface-coated positive electrode active material particles 100 include a core particle 101 and a spinel phase 102 present on at least a part of the surface of the core particle 101.
- the presence of the spinel phase 102 on at least a part of the surface of the core particle 101 can suppress the decomposition of the positive electrode active material in a high temperature environment.
- composition of the positive electrode active material means a reaction or the like in which the release of oxygen or the like occurs due to the elution of a transition metal ion such as cobalt, and a defect occurs in a part of the crystal structure.
- the positive electrode potential (vsLi / Li + ) in the fully charged state of the battery to which the positive electrode active material according to the first embodiment is applied preferably exceeds 4.20 V, more preferably 4.25 V or more, and still more preferably. It is at least 4.40 V, particularly preferably at least 4.45 V, most preferably at least 4.50 V.
- the upper limit of the positive electrode potential (vsLi / Li + ) in a fully charged state is not particularly limited, but is preferably 6 V or less, more preferably 4.6 V or less.
- the positive electrode active material particles 100 include the spinel phase 102 on the surface of the core particle 101 .
- the positive electrode active material particles 100 may not include the spinel phase 102.
- the positive electrode active material particles 100 include the spinel phase 102 on the surface of the core particle 101.
- the core particles 101 can occlude and release lithium as an electrode reactant, and include a composite oxide having a hexagonal layered rock-salt structure.
- the composite oxide is a so-called lithium transition metal composite oxide, specifically, Li, Co, Ni, Fe, Pb, Mg, Al, K, Na, Ca, Si, Ti, Sn, V, At least one element M1 selected from the group consisting of Ge, Ga, B, As, Zr, Mn, and Cr.
- the lithium transition metal oxide is mainly composed of Co.
- “mainly composed of Co” means that the atomic ratio of Co to the total amount of metal elements contained in the composite oxide is 50% or more.
- the composite oxide preferably has an average composition represented by the following formula (1).
- Li x Co y M1 1-y O 2 (1) M1 is from the group consisting of Ni, Fe, Pb, Mg, Al, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn and Cr. It contains at least one element selected.
- X and y satisfy 0.95 ⁇ x ⁇ 1.0 and 0 ⁇ y ⁇ 1.
- the crystallinity on the surface of the core particle 101 is lower than the crystallinity inside the core particle 101. More specifically, the crystallinity of the positive electrode active material particles 100 preferably decreases from the surface of the positive electrode active material particles 100 toward the inside. In this case, the crystallinity may change gradually from the surface of the positive electrode active material particles 100 toward the inside, or may change abruptly in steps or the like. Since the crystallinity on the surface of the core particle 101 is low as described above, the strain of the lattice and crystallite in the core particle 101 caused by the Li insertion / desorption reaction accompanied by the phase transition can be relaxed. Can be improved.
- the “surface of the core particle 101” refers to a region having a depth of 5 nm or less from the outermost surface of the core particle 101, and the “inside of the core particle 101” refers to a region from the outermost surface of the core particle 101 Means a region exceeding 5 nm.
- the spinel phase 102 contains an oxide containing Li and at least one element M1 described above. It is particularly preferable that this oxide contains at least one element selected from the group consisting of Mg, Al, and Ti among the elements M1, from the viewpoint of improving cycle characteristics and storage characteristics. All of the element M1 contained in the core particle 101 and the spinel phase 102 may be common, part of the element M1 contained in the core particle 101 and the spinel phase 102 may be common, or the core particle 101 And all the elements M1 contained in the spinel phase 102 may not be common.
- the spinel phase 102 preferably has an average composition represented by the following formula (2).
- Co x M2 3-x O 4 (2) (However, in the formula (2), M2 is composed of Ni, Fe, Pb, Mg, Al, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, and Cr. It contains at least one element selected from the group.
- X satisfies 0 ⁇ X ⁇ 1.
- the crystal structure of the positive electrode active material particles 100 may gradually change from the spinel phase (spinel type crystal structure) 102 toward the inside of the positive electrode active material particles 100 to a hexagonal layered rock salt type structure. , May change abruptly in steps or the like.
- the positive electrode active material particles 100 further include a compound including at least one element M2 selected from the group consisting of S, P, and F. As described above, when the positive electrode active material particles 100 further include a compound containing at least one type of element M2, performance degradation during long-term storage and long-term cycle characteristics can be particularly improved.
- the compound containing at least one element M2 functions outside the crystal system of the composite oxide, it is preferably present on at least one of the surface of the positive electrode active material particles 100 and the crystal grain boundary of the positive electrode active material particles 100. .
- the compound of the element M2 may be present on the surface of the positive electrode active material particles 100 and on a portion other than the crystal grain boundaries of the positive electrode active material particles 100.
- the compound of the element M2 may be scattered on the surface of the positive electrode active material particles 100, or the compound of the element M2 may be The surface may be coated.
- the coating may partially cover the surface of the positive electrode active material particles 100, or may cover the entire surface of the positive electrode active material particles 100.
- At least one element M1 exists on the surface of the positive electrode active material particles 100 at a specified ratio.
- the atomic ratio between the amount of Co on the surface of the positive electrode active material particles 100 and the total amount of at least one element M1 is 0.6 or more and 1.3. Or less, preferably 0.8 or more and 1.1 or less. If the atomic ratio (M1 / Co) is less than 0.6, the amount of the element M1 existing on the surface of the positive electrode active material particles 100 is too small, and the function of stabilizing the crystal structure is reduced. May not be possible.
- the “surface of the positive electrode active material particles 100” refers to a region having a depth of 5 nm or less from the outermost surface of the positive electrode active material particles 100. Further, “inside the positive electrode active material particles 100” refers to a region exceeding a depth of 5 nm from the outermost surface of the positive electrode active material particles 100.
- the concentration of the element M1 on the surface of the positive electrode active material particles 100 is preferably higher than the concentration of the element M1 inside the positive electrode active material particles 100. . More specifically, it is preferable that the concentration of the element M1 in the positive electrode active material particles 100 decreases from the surface of the positive electrode active material particles 100 toward the inside. In this case, the concentration of the element M1 may change gradually from the surface of the positive electrode active material particles 100 toward the inside, or may change rapidly in a step-like manner.
- the composition in the core particles 101 is preferably uniform. If the composition in the core particle 101 changes, the effect of adding the element M1 to stabilize the crystal structure may vary between the central portion and the outer surface portion of the core particle 101, which may adversely affect the cycle characteristics. is there.
- a region containing the element M1 at a high concentration on the surface of the positive electrode active material particles 100 functions to suppress the decomposition of the positive electrode active material in a high-temperature environment. Since the decomposition proceeds near the particle surface, it is preferable that the high concentration region of the element M1 is present on the entire surface of the positive electrode active material particles 100. However, even if the high concentration region of the element M1 is scattered on the surface of the positive electrode active material particles 100, the function of suppressing the decomposition of the positive electrode active material can be sufficiently exhibited.
- the “high-concentration region of the element M1” means that the atomic ratio between the amount of Co and the total amount of at least one element M1 (the total amount of at least one element M1 / the amount of Co) is 0.6 or more and 1.3 or more.
- the following areas are referred to.
- FIG. 2 shows an example of a Raman spectrum of the positive electrode active material according to the first embodiment of the present invention.
- the peak of the observed E g oscillation mode of a hexagonal structure in the vicinity of 480 cm -1 the peak of A 1 g oscillation mode of a hexagonal system structure is observed in the vicinity of 590 cm -1.
- E g oscillation mode is attributed to O-Co-O bending
- a 1g vibration mode is attributed to Co-O stretching.
- a peak of the A 1g vibration mode of the spinel phase 102 is observed in a range of 600 cm ⁇ 1 to 700 cm ⁇ 1 .
- the half-width of the peak of the A 1g vibration mode having a hexagonal structure in the Raman spectrum is from 10 cm -1 to 17 cm -1 , preferably from 12 cm -1 to 15 cm -1 .
- the half width means the full width at half maximum (FWHM).
- the half width is less than 10 cm ⁇ 1 , the crystallinity of the surface of the positive electrode active material particles 100 is high, so that good storage characteristics can be obtained, but the cycle characteristics may be deteriorated.
- the half-value width exceeds 17 cm ⁇ 1 , the crystallinity of the surface of the positive electrode active material particles 100 is low, so that good cycle characteristics can be obtained.
- the peak intensity ratio IA 1g-H / IE g of the peak intensity IA 1g-H of the A 1g vibration mode of the hexagonal structure and the peak intensity IE g of the E g vibration mode of the hexagonal structure in the Raman spectrum is 1 0.1 or more and 1.9 or less, preferably 1.3 or more and 1.7 or less.
- the peak intensity ratio IA 1g-H / IE g is less than 1.1, due to the low crystallinity of the surface of the positive electrode active material particles 100, but excellent cycle characteristics can be obtained, there is a possibility that storage characteristics is reduced .
- the spinel phase is generated when the amount of Li element on the surface of the positive electrode active material particles 100 is reduced in the synthesis of the composite oxide particles.
- the positive electrode active material particles 100 synthesized in such a state have a distribution of the additive element M1. Is particularly likely to be unevenly distributed near the surface.
- the spinel phase be present to such an extent that the spinel phase can be observed, for example, by local observation using a transmission electron microscope (TEM).
- TEM transmission electron microscope
- the peak intensity ratio IA gS / IA gH is 0. If it exceeds 0.04, the amount of the spinel phase 102 existing on the surface of the core particle 101 is too large, and the cycle characteristics and the storage characteristics may decrease due to an increase in resistance.
- the positive electrode active material according to the first embodiment of the present invention is produced, for example, as follows. First, a powder of composite oxide particles containing Li, Co, and at least one element M1 and having a hexagonal layered rock salt type structure is prepared.
- the prepared composite oxide particles, lithium carbonate, cobalt oxide, Ni-containing compound, Fe-containing compound, Pb-containing compound, Mg-containing compound, Al-containing compound, K-containing compound, Na-containing compound, and Ca From the group consisting of compound containing, Si containing compound, Ti containing compound, Sn containing compound, V containing compound, Ge containing compound, Ga containing compound, B containing compound, As containing compound, Zr containing compound, Mn containing compound and Cr containing compound A mixture is obtained by mixing with at least one selected compound.
- the atomic ratio between the amount of Co and the total amount of at least one element M1 on the surface of the finally obtained cathode active material particles 100 is 0.6 or more and 1 or more.
- the mixing ratio of each material is adjusted so as to be 0.3 or less.
- at least one of lithium phosphate, lithium fluoride and lithium sulfide may be used.
- the mixture is stirred at a high speed, heat-treated under, for example, an air stream, and then pulverized. Thereby, the positive electrode active material according to the first embodiment is obtained.
- the processing time of the high-speed stirring is preferably from 2 hours to 5 hours. If the processing time of the high-speed stirring is less than 2 hours, the peak intensity ratio IA 1g-H / IE g may be less than 1.1. On the other hand, if the processing time of the high-speed stirring exceeds 5 hours, the peak intensity ratio IA 1g-H / IE g may exceed 1.9.
- the temperature of the heat treatment is preferably from 750 ° C to 850 ° C. If the temperature of the heat treatment is lower than 750 ° C., the half width of the peak of the A 1g vibration mode having a hexagonal structure may be lower than 10 cm ⁇ 1 . On the other hand, when the temperature of the heat treatment exceeds 850 ° C., the half width of the peak of the A 1g vibration mode having a hexagonal structure may exceed 17 cm ⁇ 1 .
- the positive electrode active material according to the first embodiment includes a powder of surface-coated positive electrode active material particles 100.
- the positive electrode active material particles 100 include a core particle 101 and a spinel phase 102 present on at least a part of the surface of the core particle 101.
- the core particles 101 include the positive electrode active material particles 100 including a composite oxide having a hexagonal structure.
- the composite oxide is composed of Li, Co, Ni, Fe, Pb, Mg, Al, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn and Cr.
- the spinel phase 102 includes an oxide containing Li and at least one element M1.
- the atomic ratio of the amount of Co on the particle surface to the total amount of at least one element M1 is 0.6 or more and 1.3 or less, and the hexagonal system in the Raman spectrum
- the half-width of the peak of the A 1g vibration mode of the structure is 10 cm ⁇ 1 or more and 17 cm ⁇ 1 or less, the peak intensity IA 1g-H of the A 1g vibration mode of the hexagonal structure in the Raman spectrum, and the peak intensity IA 1g-H of the hexagonal structure.
- the peak intensity ratio IA 1g-H / IE g with respect to the peak intensity IE g in the E g vibration mode is 1.1 or more and 1.9 or less. Thereby, both cycle characteristics and storage characteristics can be achieved.
- non-aqueous electrolyte secondary batteries of various shapes and sizes (hereinafter, simply referred to as “batteries”) can be manufactured.
- batteries non-aqueous electrolyte secondary batteries of various shapes and sizes
- FIG. 3 shows an example of the configuration of the battery according to the second embodiment of the present invention.
- the battery according to the second embodiment is a so-called laminate type battery, in which the electrode body 20 to which the positive electrode lead 11 and the negative electrode lead 12 are attached is housed inside the film-shaped exterior material 10. It is possible to reduce the weight and thickness.
- the positive electrode lead 11 and the negative electrode lead 12 each extend from the inside of the exterior material 10 to the outside, for example, are led out in the same direction.
- the positive electrode lead 11 and the negative electrode lead 12 are each made of a metal material such as Al, Cu, Ni, or stainless steel, for example, and have a thin plate shape or a mesh shape, respectively.
- the outer package 10 is made of, for example, a rectangular aluminum laminate film in which a nylon film, an aluminum foil, and a polyethylene film are laminated in this order.
- the exterior material 10 is disposed, for example, such that the polyethylene film side and the electrode body 20 face each other, and the respective outer edges are adhered to each other by fusion bonding or an adhesive.
- An adhesive film 13 for preventing outside air from entering is inserted between the exterior material 10 and the positive electrode lead 11 and the negative electrode lead 12.
- the adhesive film 13 is made of a material having adhesiveness to the positive electrode lead 11 and the negative electrode lead 12, for example, a polyolefin resin such as polyethylene, polypropylene, modified polyethylene or modified polypropylene.
- the package 10 may be made of a laminated film having another structure, a polymer film such as polypropylene, or a metal film, instead of the above-described aluminum laminated film.
- a polymer film such as polypropylene
- a metal film instead of the above-described aluminum laminated film.
- it may be constituted by a laminated film in which a polymer film is laminated on one or both sides of an aluminum film as a core material.
- FIG. 4 is a cross-sectional view of the electrode body 20 shown in FIG. 3 along the line IV-IV.
- the electrode body 20 is of a wound type, and has a configuration in which a long positive electrode 21 and a long negative electrode 22 are laminated via a long separator 23 and wound flat and spirally. The outermost portion is protected by a protective tape 24.
- An electrolytic solution as an electrolyte is injected into the exterior material 10 and impregnated in the positive electrode 21, the negative electrode 22, and the separator 23.
- the positive electrode 21 includes, for example, a positive electrode current collector 21A and positive electrode active material layers 21B provided on both surfaces of the positive electrode current collector 21A.
- the positive electrode current collector 21A is made of, for example, a metal foil such as an aluminum foil, a nickel foil, and a stainless steel foil.
- the positive electrode active material layer 21B contains a positive electrode active material.
- the positive electrode active material layer 21B may further include at least one of a binder and a conductive agent as necessary.
- the positive electrode active material is the positive electrode active material according to the above-described first embodiment.
- binder for example, at least one selected from the group consisting of resin materials such as polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, styrene butadiene rubber, and carboxymethyl cellulose, and copolymers mainly containing these resin materials Is used.
- resin materials such as polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, styrene butadiene rubber, and carboxymethyl cellulose, and copolymers mainly containing these resin materials Is used.
- the conductive agent for example, at least one carbon material selected from the group consisting of graphite, carbon fiber, carbon black, Ketjen black, carbon nanotube, and the like is used.
- the conductive agent may be any material having conductivity, and is not limited to a carbon material.
- a metal material or a conductive polymer material may be used as the conductive agent.
- the negative electrode 22 includes, for example, a negative electrode current collector 22A and negative electrode active material layers 22B provided on both surfaces of the negative electrode current collector 22A.
- the negative electrode current collector 22A is made of, for example, a metal foil such as a copper foil, a nickel foil, and a stainless steel foil.
- the negative electrode active material layer 22B includes one or more negative electrode active materials capable of inserting and extracting lithium.
- the anode active material layer 22B may further include at least one of a binder and a conductive agent as needed.
- the electrochemical equivalent of the negative electrode 22 or the negative electrode active material is larger than the electrochemical equivalent of the positive electrode 21.
- lithium metal does not deposit on the negative electrode 22 during charging. Is preferred.
- the negative electrode active material examples include carbon materials such as non-graphitizable carbon, easily graphitizable carbon, graphite, pyrolytic carbons, cokes, glassy carbons, organic polymer compound fired bodies, carbon fibers, and activated carbon. Is mentioned. Among them, the cokes include pitch coke, needle coke, petroleum coke and the like.
- An organic polymer compound fired body is obtained by firing a polymer material such as a phenol resin or a furan resin at an appropriate temperature and carbonizing the material. Some of the materials are hardly graphitizable carbon or easily graphitizable carbon. Some are classified as.
- These carbon materials are preferable because a change in crystal structure that occurs during charge and discharge is very small, a high charge and discharge capacity can be obtained, and good cycle characteristics can be obtained.
- graphite is preferable because it has a large electrochemical equivalent and can obtain a high energy density.
- non-graphitizable carbon is preferable because excellent cycle characteristics can be obtained.
- a material having a low charge / discharge potential specifically, a material having a charge / discharge potential close to lithium metal is preferable because a high energy density of a battery can be easily realized.
- a material containing at least one of a metal element and a metalloid element as a constituent element for example, an alloy, a compound, or a mixture
- a high energy density can be obtained.
- alloys include alloys containing one or more metal elements and one or more metalloid elements in addition to alloys composed of two or more metal elements. Further, it may contain a non-metallic element.
- the structure includes a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or a structure in which two or more of them coexist.
- a negative electrode active material for example, a metal element or a metalloid element capable of forming an alloy with lithium is given.
- a metal element or a metalloid element capable of forming an alloy with lithium.
- Specific examples include Mg, B, Al, Ti, Ga, In, Si, Ge, Sn, Pb, Bi, Cd, Ag, Zn, Hf, Zr, Y, Pd, and Pt. These may be crystalline or amorphous.
- a material containing a metal element or a metalloid element belonging to Group 4B in the short-periodic table as a constituent element is preferable, and more preferable is a substance containing at least one of Si and Sn as a constituent element. This is because Si and Sn have a large ability to insert and extract lithium and can obtain a high energy density.
- Examples of such a negative electrode active material include a simple substance, an alloy, or a compound of Si, a simple substance, an alloy, or a compound of Sn, and a material having at least one or more of them.
- alloy of Si for example, Sn, Ni, Cu, Fe, Co, Mn, Zn, In, Ag, Ti, Ge, Bi, Sb, Nb, Mo, Al
- the second constituent element other than Si examples include those containing at least one selected from the group consisting of P, Ga, and Cr.
- alloy of Sn for example, as the second constituent element other than Sn, Si, Ni, Cu, Fe, Co, Mn, Zn, In, Ag, Ti, Ge, Bi, Sb, Nb, Mo, Al, Examples include those containing at least one selected from the group consisting of P, Ga, and Cr.
- Examples of the compound of Sn or the compound of Si include those containing O or C as a constituent element. These compounds may include the second constituent element described above.
- the Sn-based negative electrode active material contains Co, Sn, and C as constituent elements and has a low crystallinity or an amorphous structure.
- Examples of other negative electrode active materials include, for example, metal oxides or polymer compounds capable of inserting and extracting lithium.
- metal oxide include lithium titanium oxide containing Li and Ti, such as lithium titanate (Li 4 Ti 5 O 12 ), iron oxide, ruthenium oxide, and molybdenum oxide.
- the polymer compound include polyacetylene, polyaniline, and polypyrrole.
- binder As the binder, the same binder as that for the positive electrode active material layer 21B can be used.
- the same material as that of the positive electrode active material layer 21B can be used.
- the separator 23 separates the positive electrode 21 from the negative electrode 22 and allows lithium ions to pass therethrough while preventing current short circuit due to contact between the two electrodes.
- the separator 23 is made of, for example, a porous material made of polytetrafluoroethylene, polyolefin resin (such as polypropylene (PP) or polyethylene (PE)), acrylic resin, styrene resin, polyester resin or nylon resin, or a resin obtained by blending these resins. It is made of a porous film, and may have a structure in which two or more of these porous films are laminated.
- a porous film made of polyolefin is preferable because it has an excellent short circuit prevention effect and can improve the safety of the battery by a shutdown effect.
- polyethylene is preferable as a material constituting the separator 23 because it can obtain a shutdown effect in the range of 100 ° C. or more and 160 ° C. or less and has excellent electrochemical stability.
- low-density polyethylene, high-density polyethylene, and linear polyethylene are suitably used because they have an appropriate melting temperature and are easily available.
- a material obtained by copolymerizing or blending a resin having chemical stability with polyethylene or polypropylene can be used.
- the porous membrane may have a structure of three or more layers in which a polypropylene layer, a polyethylene layer, and a polypropylene layer are sequentially laminated.
- a single-layer substrate having 100 wt% of PP or 100 wt% of PE can be used.
- the method for producing the separator 23 may be either a wet method or a dry method.
- a non-woven fabric may be used as the separator 23.
- Aramid fiber, glass fiber, polyolefin fiber, polyethylene terephthalate (PET) fiber, nylon fiber, or the like can be used as the fiber constituting the nonwoven fabric. Further, these two or more kinds of fibers may be mixed to form a nonwoven fabric.
- the separator 23 may have a configuration including a base material and a surface layer provided on one or both surfaces of the base material.
- the surface layer includes inorganic particles having electrical insulation properties, and a resin material that binds the inorganic particles to the surface of the base material and binds the inorganic particles to each other.
- This resin material may be, for example, fibrillated and have a three-dimensional network structure in which a plurality of fibrils are connected.
- the inorganic particles are supported on the resin material having the three-dimensional network structure.
- the resin material may bind the surface of the base material or the inorganic particles without fibrillation. In this case, higher binding properties can be obtained.
- the base material is a porous film made of an insulating film that transmits lithium ions and has a predetermined mechanical strength. Since the electrolyte solution is held in the pores of the base material, the base material has resistance to the electrolyte solution. , High reactivity, low reactivity, and difficult to expand.
- the above-described resin material or nonwoven fabric forming the separator 23 can be used.
- the inorganic particles include at least one selected from the group consisting of metal oxides, metal nitrides, metal carbides, metal sulfides, and the like.
- metal oxide aluminum oxide (alumina, Al 2 O 3 ), boehmite (hydrated aluminum oxide), magnesium oxide (magnesia, MgO), titanium oxide (titania, TiO 2 ), zirconium oxide (zirconia, ZrO 2) ), Silicon oxide (silica, SiO 2 ) or yttrium oxide (yttria, Y 2 O 3 ) or the like can be suitably used.
- silicon nitride Si 3 N 4
- aluminum nitride AlN
- boron nitride BN
- titanium nitride TiN
- metal carbide silicon carbide (SiC) or boron carbide (B 4 C)
- metal sulfide barium sulfate (BaSO 4 ) or the like can be suitably used.
- alumina titania (especially having a rutile structure), silica or magnesia, and it is more preferable to use alumina.
- the inorganic particles are made of a porous aluminosilicate such as zeolite (M 2 / n O.Al 2 O 3 .xSiO 2 .yH 2 O, M is a metal element, x ⁇ 2, y ⁇ 0); Salts and minerals such as barium titanate (BaTiO 3 ) or strontium titanate (SrTiO 3 ) may be included.
- the inorganic particles have oxidation resistance and heat resistance, and the surface layer on the side facing the positive electrode containing the inorganic particles has strong resistance to an oxidizing environment near the positive electrode during charging.
- the shape of the inorganic particles is not particularly limited, and any of a spherical shape, a plate shape, a fiber shape, a cubic shape, and a random shape can be used.
- the particle size of the inorganic particles is preferably in the range of 1 nm or more and 10 ⁇ m or less. If the thickness is smaller than 1 nm, it is difficult to obtain, and if the thickness is larger than 10 ⁇ m, the distance between the electrodes becomes large, so that a sufficient amount of active material cannot be obtained in a limited space, and the battery capacity decreases.
- the resin material constituting the surface layer examples include fluorine-containing resins such as polyvinylidene fluoride and polytetrafluoroethylene, fluorine-containing rubbers such as vinylidene fluoride-tetrafluoroethylene copolymer and ethylene-tetrafluoroethylene copolymer, and styrene.
- fluorine-containing resins such as polyvinylidene fluoride and polytetrafluoroethylene
- fluorine-containing rubbers such as vinylidene fluoride-tetrafluoroethylene copolymer and ethylene-tetrafluoroethylene copolymer
- styrene examples include polystyrene.
- -Butadiene copolymer or hydride thereof acrylonitrile-butadiene copolymer or hydride thereof, acrylonitrile-butadiene-styrene copolymer or hydride thereof, methacrylate-acrylate copolymer, styrene-acrylate Copolymers, acrylonitrile-acrylate copolymers, rubbers such as ethylene propylene rubber, polyvinyl alcohol, polyvinyl acetate, etc., ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, carboxymethyl Cellulose derivatives such as cellulose, polyphenylene ether, polysulfone, polyethersulfone, polyphenylene sulfide, polyetherimide, polyimide, polyamide such as wholly aromatic polyamide (aramid), polyamideimide, polyacrylonitrile, polyvinyl alcohol, polyether, acrylic resin Alternatively, a resin having high heat resistance such as polyester having at least one
- resin materials may be used alone or as a mixture of two or more.
- a fluororesin such as polyvinylidene fluoride is preferable, and from the viewpoint of heat resistance, it is preferable to contain aramid or polyamideimide.
- a slurry composed of a matrix resin, a solvent and inorganic particles is applied on a substrate (porous film), and the slurry is passed through a poor solvent for the matrix resin and a solvent-friendly bath of the solvent.
- a method of phase separation and then drying can be used.
- the inorganic particles described above may be contained in a porous film as a substrate. Further, the surface layer may not include the inorganic particles, and may be formed only of the resin material.
- the electrolyte is a so-called non-aqueous electrolyte, and includes an organic solvent (non-aqueous solvent) and an electrolyte salt dissolved in the organic solvent.
- the electrolytic solution may contain a known additive to improve battery characteristics. Note that, instead of the electrolytic solution, an electrolyte layer containing the electrolytic solution and a polymer compound serving as a holder for holding the electrolytic solution may be used. In this case, the electrolyte layer may be in a gel state.
- a cyclic carbonate such as ethylene carbonate or propylene carbonate can be used, and it is preferable to use one of ethylene carbonate and propylene carbonate, particularly to use a mixture of both. This is because the cycle characteristics can be further improved.
- organic solvent it is preferable to use a mixture of chain carbonates such as diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate or methylpropyl carbonate in addition to these cyclic carbonates. This is because high ionic conductivity can be obtained.
- the organic solvent further contains 2,4-difluoroanisole or vinylene carbonate. This is because 2,4-difluoroanisole can further improve the discharge capacity, and vinylene carbonate can further improve the cycle characteristics. Therefore, it is preferable to use a mixture of these, because the discharge capacity and cycle characteristics can be further improved.
- organic solvents include butylene carbonate, ⁇ -butyrolactone, ⁇ -valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolan, and 4-methyl-1,3 -Dioxolane, methyl acetate, methyl propionate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropyronitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N- Examples thereof include dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, dimethylsulfoxide, and trimethyl phosphate.
- Examples of the electrolyte salt include a lithium salt, and one kind may be used alone, or two or more kinds may be used in combination.
- the lithium salt LiPF 6, LiBF 4, LiAsF 6, LiClO 4, LiB (C 6 H 5) 4, LiCH 3 SO 3, LiCF 3 SO 3, LiN (SO 2 CF 3) 2, LiC (SO 2 CF 3 ) 3 , LiAlCl 4 , LiSiF 6 , LiCl, lithium difluoro [oxolate-O, O ′] borate, lithium bisoxalate borate, or LiBr.
- LiPF 6 is preferable because high ionic conductivity can be obtained and cycle characteristics can be further improved.
- the positive electrode 21 is manufactured as follows. First, for example, a positive electrode mixture is prepared by mixing a positive electrode active material, a conductive agent, and a binder, and this positive electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone (NMP) to form a paste. Is prepared. Next, the positive electrode mixture slurry is applied to the positive electrode current collector 21A, the solvent is dried, and compression molding is performed by a roll press or the like to form the positive electrode active material layer 21B, and the positive electrode 21 is obtained.
- NMP N-methyl-2-pyrrolidone
- the negative electrode 22 is manufactured as follows. First, for example, a negative electrode mixture is prepared by mixing a negative electrode active material and a binder, and this negative electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to prepare a paste-like negative electrode mixture slurry. I do. Next, the negative electrode mixture slurry is applied to the negative electrode current collector 22A, the solvent is dried, and compression molding is performed with a roll press or the like to form the negative electrode active material layer 22B, and the negative electrode 22 is obtained.
- a negative electrode mixture is prepared by mixing a negative electrode active material and a binder, and this negative electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to prepare a paste-like negative electrode mixture slurry. I do.
- the negative electrode mixture slurry is applied to the negative electrode current collector 22A, the solvent is dried, and compression molding is performed with a roll press or the like to form the negative electrode active material layer 22B, and the negative electrode 22 is
- the wound electrode body 20 is manufactured as follows. First, the cathode lead 11 is attached to one end of the cathode current collector 21A by welding, and the anode lead 12 is attached to one end of the anode current collector 22A by welding. Next, the positive electrode 21 and the negative electrode 22 are wrapped around a flat core with a separator 23 interposed therebetween, and are wound many times in the longitudinal direction. Get.
- the electrode body 20 is sealed with the exterior material 10 as follows. First, the electrode body 20 is sandwiched between the package members 10, and the outer peripheral edge portion excluding one side is heat-fused to form a bag, which is housed inside the package member 10. At that time, the adhesive film 13 is inserted between the positive electrode lead 11 and the negative electrode lead 12 and the exterior material 10. Note that the adhesive film 13 may be attached to the positive electrode lead 11 and the negative electrode lead 12 in advance. Next, after injecting the electrolytic solution into the exterior material 10 from one side of the unfused part, one side of the unfused part is heat-sealed in a vacuum atmosphere and sealed. Thus, the batteries shown in FIGS. 3 and 4 are obtained.
- the positive electrode active material layer 21B includes the positive electrode active material according to the first embodiment, so that both cycle characteristics and storage characteristics can be achieved. In particular, both cycle characteristics and storage characteristics can be achieved in a high-temperature environment.
- FIG. 5 shows an example of the configuration of an electronic device 400 according to the third embodiment of the present invention.
- the electronic device 400 includes an electronic circuit 401 of the electronic device main body and the battery pack 300.
- Battery pack 300 is electrically connected to electronic circuit 401 via positive electrode terminal 331a and negative electrode terminal 331b.
- the electronic device 400 may have a configuration in which the battery pack 300 is detachable.
- Examples of the electronic device 400 include a notebook personal computer, a tablet computer, a mobile phone (for example, a smartphone), a portable information terminal (Personal Digital Assistants: PDA), a display device (LCD (Liquid Crystal Display), and an EL (Electro Luminescence).
- PDA Personal Digital Assistants
- LCD Liquid Crystal Display
- EL Electro Luminescence
- the electronic circuit 401 includes, for example, a CPU (Central Processing Unit), a peripheral logic unit, an interface unit, a storage unit, and the like, and controls the entire electronic device 400.
- a CPU Central Processing Unit
- the battery pack 300 includes an assembled battery 301 and a charge / discharge circuit 302.
- the battery pack 300 may further include an exterior material (not shown) that accommodates the assembled battery 301 and the charging / discharging circuit 302 as necessary.
- the assembled battery 301 is configured by connecting a plurality of secondary batteries 301a in series and / or in parallel.
- the plurality of secondary batteries 301a are connected in, for example, n parallel and m series (n and m are positive integers).
- FIG. 5 shows an example in which six rechargeable batteries 301a are connected in two parallel and three series (2P3S).
- the secondary battery 301a the battery according to the above-described second embodiment is used.
- the battery pack 300 includes an assembled battery 301 including a plurality of secondary batteries 301a.
- the battery pack 300 includes a single secondary battery 301a instead of the assembled battery 301. May be adopted.
- the charging / discharging circuit 302 is a control unit that controls charging / discharging of the battery pack 301. Specifically, at the time of charging, the charge / discharge circuit 302 controls charging of the battery pack 301. On the other hand, at the time of discharging (that is, at the time of using the electronic device 400), the charging / discharging circuit 302 controls discharging to the electronic device 400.
- the exterior material for example, a case made of a metal, a polymer resin, or a composite material thereof can be used.
- the composite material include a laminate in which a metal layer and a polymer resin layer are laminated.
- Step (1) First, commercially available lithium carbonate, cobalt oxide, aluminum hydroxide and magnesium carbonate were mixed such that the molar ratios of Li, Co, Mg and Al were 1.02: 0.99: 0.005: 0.005, respectively. By doing so, a mixture was obtained. Next, this mixture was fired in air at 1000 ° C. for 6 hours, and gradually cooled to obtain a powder of Mg and Al-containing LiCoO 2 particles having an average particle diameter of 20 ⁇ m and a specific surface area of 0.3 m 2 / g. .
- Step (2) First, commercially available lithium carbonate, cobalt oxide, magnesium carbonate, aluminum hydroxide and titanium oxide were mixed with Li, Co, Mg, Al and Ti at a molar ratio of 1.02: 0.85: 0.05: 0.05, respectively. : 0.05 to obtain a mixture. Next, 5% by mass of this mixture was added to 95% by mass of the powder (base material) of LCO 2 particles obtained in the step (1), and the mixture was treated with a high-speed stirrer for 3 hours. After firing for 3 hours, the mixture was finely pulverized with a ball mill. As a result, a powder of positive electrode active material particles containing Mg, Al, and Ti at a high concentration on the surface was obtained.
- Example 2-1> In the same manner as in Example 1 except that the treatment time in the high-speed stirrer in the step (2) was set to 2 hours, powder of positive electrode active material particles having Mg, Al, and Ti present on the surface in a high concentration was obtained.
- Example 2-2> In the same manner as in Example 1 except that the treatment time in the high-speed stirrer in step (2) was set to 5 hours, powder of positive electrode active material particles having Mg, Al, and Ti present on the surface in high concentration was obtained.
- Example 3-1> In the same manner as in Example 1 except that the firing temperature in the step (2) was set to 750 ° C., powder of positive electrode active material particles having Mg, Al, and Ti present on the surface in a high concentration was obtained.
- Example 3-2> In the same manner as in Example 1 except that the firing temperature in the step (2) was set to 850 ° C., powder of positive electrode active material particles having Mg, Al, and Ti present on the surface in a high concentration was obtained.
- Example 4-1> In the same manner as in Example 1 except that the molar ratio of Li, Co, Mg, Al and Ti in the step (2) was set to 1.02: 0.79: 0.07: 0.07: 0.07, respectively. , Mg, Al and Ti were obtained in the form of positive electrode active material particles having a high concentration on the surface.
- Example 4-2> In the same manner as in Example 1 except that the molar ratio of Li, Co, Mg, Al and Ti in the step (2) was set to 1.02: 0.91: 0.03: 0.03: 0.03, respectively. , Mg, Al and Ti were obtained in the form of positive electrode active material particles having a high concentration on the surface.
- Example 5 In the step (2), commercially available lithium carbonate, cobalt oxide, aluminum hydroxide and titanium oxide were prepared by changing the molar ratio of Li, Co, Al and Ti to 1.02: 0.90: 0.05: 0.05, respectively. In this manner, a powder of positive electrode active material particles having a high concentration of Al and Ti on the surface was obtained in the same manner as in Example 1 except that a mixture was obtained.
- step (2) commercially available lithium carbonate, cobalt oxide, magnesium carbonate, and aluminum hydroxide were converted to a molar ratio of Li, Co, Mg, and Al of 1.02: 0.90: 0.05: 0.05, respectively.
- a powder of the positive electrode active material particles in which Mg and Al exist at a high concentration on the surface in the same manner as in Example 1 except that a mixture was obtained.
- Example 7 In the step (2), commercially available lithium carbonate, cobalt oxide, magnesium carbonate, and titanium oxide are converted to a molar ratio of Li, Co, Mg, and Ti of 1.02: 0.90: 0.05: 0.05, respectively. In the same manner as in Example 1 except that a mixture was obtained, a powder of positive electrode active material particles containing Mg and Ti at a high concentration on the surface was obtained.
- Example 8 In step (2), commercially available lithium carbonate, cobalt oxide, and aluminum hydroxide are mixed such that the molar ratios of Li, Co, and Al are 1.02: 0.95: 0.05, respectively, to form a mixture. In the same manner as in Example 1 except that the powder was obtained, powder of positive electrode active material particles having Al at a high concentration on the surface was obtained.
- step (2) commercially available lithium carbonate, cobalt oxide, and titanium oxide are mixed so that the molar ratios of Li, Co, and Ti are 1.02: 0.95: 0.05, respectively. Except for that, in the same manner as in Example 1, powder of positive electrode active material particles having a high concentration of Ti on the surface was obtained.
- step (2) commercially available lithium carbonate, cobalt oxide, and magnesium carbonate are mixed such that the molar ratios of Li, Co, and Mg are 1.02: 0.95: 0.05, respectively. Except for that, in the same manner as in Example 1, a powder of positive electrode active material particles having Mg at a high concentration on the surface was obtained.
- Example 11 In the same manner as in Example 1 except that lithium phosphate was used in place of lithium carbonate in step (2), a positive electrode active material in which Mg, Al, and Ti were present at a high concentration on the surface and P was also present on the surface. A powder of material particles was obtained.
- Example 12 In the same manner as in Example 1 except that lithium fluoride was used in place of lithium carbonate in step (2), a positive electrode active material in which Mg, Al, and Ti were present at a high concentration on the surface and F was also present on the surface. A powder of material particles was obtained.
- Example 13> A positive electrode active material in which Mg, Al, and Ti are present at a high concentration on the surface and S is also present on the surface in the same manner as in Example 1 except that lithium sulfide is used instead of lithium carbonate in step (2). A powder of particles was obtained.
- step (2) when treating with a high-speed stirrer, Mg, Al, and Ti are added at a high concentration to the surface in the same manner as in Example 1 except that 1200 ppm of LiAlMg-containing cobalt oxide produced by the method described below is mixed. A powder of existing positive electrode active material particles was obtained.
- step (1) commercially available lithium carbonate and cobalt oxide were mixed so that the molar ratio of Li and Co was 1.02: 1.00, respectively, to obtain a mixture.
- step (2) commercially available lithium carbonate and cobalt oxide were mixed so that the molar ratio of Li and Co was 1.02: 1.00, respectively, to obtain a mixture.
- step (2) commercially available lithium carbonate and cobalt oxide were mixed so that the molar ratio of Li and Co was 1.02: 1.00, respectively, to obtain a mixture.
- a powder of the positive electrode active material particles was obtained in the same manner as in Example 1.
- X-ray photoelectron spectroscopy First, using a scanning X-ray photoelectron spectrometer (Quantera SXM) manufactured by ULVAC-PHI, Inc., the measurement was performed under the following measurement conditions.
- X-ray source monochromatic Al-K ⁇ (1486.6 eV)
- X-ray spot diameter 100 ⁇ m
- the surface atomic concentration was calculated using a relative sensitivity factor provided by ULVAC-PHI Co., Ltd., and the element M1 (at least of Mg, Al and Ti) with respect to the Co amount was calculated.
- the atomic ratio (total amount of M1 / Co amount) of the total amount of one kind of element M1) was calculated.
- the A 1 g peak intensity ratio IA 1g-H / IE g of the peak intensity IE g of E g oscillation mode of a peak intensity IA 1 g-H and hexagonal structure vibration mode of the hexagonal structure was calculated.
- a positive electrode was produced as follows. First, 98% by weight of a positive electrode active material (powder of positive electrode active material particles), 0.8% by weight of amorphous carbon powder (Ketjen black) and 1.2% by weight of polyvinylidene fluoride (PVdF) were mixed. A mixture was prepared. Subsequently, this positive electrode mixture is dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode mixture slurry, and this positive electrode mixture slurry is uniformly applied to a positive electrode current collector made of a strip-shaped aluminum foil. It was applied to form a coating layer. Next, the coating layer was dried with hot air, punched out to a diameter of 15 mm, and compression-molded with a hydraulic press to produce a positive electrode.
- NMP N-methyl-2-pyrrolidone
- a negative electrode was produced as follows. First, 95% by weight of graphite powder and 5% by weight of PVdF were mixed to prepare a negative electrode mixture. Next, the negative electrode mixture is dispersed in N-methyl-2-pyrrolidone to prepare a negative electrode mixture slurry, and then the negative electrode mixture slurry is uniformly applied to a negative electrode current collector made of a strip-shaped copper foil. A layer was formed. Next, the coating layer was dried with hot air, punched out to a diameter of 16 mm, and compression-molded with a hydraulic press to produce a negative electrode.
- a battery was manufactured as follows. First, an electrode body was produced by laminating a positive electrode and a negative electrode via a porous polyolefin film. Subsequently, ethylene carbonate and propylene carbonate were mixed at a volume mixing ratio of 1: 1 to prepare a mixed solution. Next, LiPF 6 was dissolved in this mixed solution to a concentration of 1 mol / dm 3 to prepare a non-aqueous electrolyte. Finally, a CR2032 coin-type battery was manufactured using the above-described electrode body and the electrolytic solution.
- Co eluted amount (Co concentration) / (weight of active material contained in positive electrode)
- the measured amount of Co eluted in each of the examples and comparative examples was converted to a relative value where the amount of Co eluted in Example 5 was 100.
- Table 1 shows the configurations and evaluation results of the positive electrode active materials of Examples 1 to 14 and Comparative Examples 1 to 4-2.
- Table 1 shows the configurations and evaluation results of the positive electrode active materials of Examples 1 to 14 and Comparative Examples 1 to 4-2.
- ⁇ 0.04 means “IA 1g-S / IA 1g-H ⁇ 0.04”.
- the lithium transition metal composite oxide contains Li, Co, and at least one element M1 selected from the group consisting of Mg, Al, and Ti, and the at least one element M1 is a positive electrode active material. Present on the surface of the particle.
- the atomic ratio of the Co amount on the particle surface to the total amount of the at least one element M1 (total amount of the at least one element M1 / Co amount) is 0.6 or more and 1.3 or less.
- the half-width of the peak of the A 1g vibration mode having a hexagonal structure in the Raman spectrum is 10 cm ⁇ 1 or more and 17 cm ⁇ 1 or less.
- the positive electrode active materials of Examples 1 to 13 further include the following configuration (5) in addition to the above configurations (1) to (4), so that the cycle characteristics and storage characteristics in a high temperature environment are further improved. can do.
- (5) of the spinel phase in the Raman spectrum A 1 g and peak intensity IA 1 g-S of the vibration mode, the peak intensity of the A 1 g oscillation mode of a hexagonal system structure IA 1 g-H and of the peak intensity ratio IA 1g-S / IA 1g -H is 0.04 or less.
- the positive electrode active materials of Comparative Examples 1 to 4-2 do not have at least one of the above configurations (1) to (4), and thus have both cycle characteristics and storage characteristics under a high temperature environment. I can't.
- the present invention is not limited to the above-described first to fourth embodiments, but is based on the technical idea of the present invention. Various modifications are possible.
- the configurations, methods, steps, shapes, materials, numerical values, and the like described in the first to third embodiments are merely examples, and different configurations, methods, steps, shapes, and materials may be used as necessary. And numerical values may be used.
Abstract
Description
1 第1の実施形態(正極活物質の例)
2 第2の実施形態(ラミネート型電池の例)
3 第3の実施形態(電子機器の例)
[概要]
本発明者らの知見によれば、六方晶系構造を有する複合酸化物を含む正極活物質粒子では、その表面の状態が充放電サイクル特性(以下単に「サイクル特性」という。)および保存特性に大きく影響する。そこで、本発明者らは、上記の知見に基づき、サイクル特性および保存特性を両立すべく、六方晶系構造を有する複合酸化物を含み、この複合酸化物が、Liと、Coと、Ni、Fe、Pb、Mg、Al、K、Na、Ca、Si、Ti、Sn、V、Ge、Ga、B、As、Zr、MnおよびCrからなる群より選ばれる少なくとも1種の元素M1とを含む正極活物質粒子について鋭意検討を行った。その結果、正極活物質粒子の表面における、少なくとも1種の元素M1の含有量と結晶構造とを規定することを見出すに至った。
(A)正極活物質粒子の表面におけるCo量と少なくとも1種の元素M1の総量との原子比(少なくとも1種の元素M1の総量/Co量)を0.6以上1.3以下とすることで、正極活物質粒子の表面における、少なくとも1種の元素M1の含有量を規定する。
(B)ラマンスペクトルにおける六方晶系構造のA1g振動モードのピークの半値幅を10cm-1以上17cm-1以下とし、ラマンスペクトルにおける六方晶系構造のA1g振動モードのピーク強度IA1g-Hと六方晶系構造のEg振動モードのピーク強度IEgとのピーク強度比IA1g-H/IEgを1.1以上1.9以下とすることで、正極活物質粒子の表面における結晶構造を規定する。
図1は、本発明の第1の実施形態に係る正極活物質の構成の一例を示す。第1の実施形態に係る正極活物質は、いわゆる非水電解質二次電池用の正極活物質であり、表面被覆型の正極活物質粒子100の粉末を含む。表面被覆型の正極活物質粒子100は、コア粒子101と、コア粒子101の表面の少なくとも一部に存在するスピネル相102とを含む。このようにコア粒子101の表面の少なくとも一部にスピネル相102が存在することで、高温環境下における正極活物質の分解を抑制することができる。なお、本明細書において“正極活物質の分解”とは、コバルト等の遷移金属イオンの溶出により、酸素等の放出が発生し、結晶構造の一部に欠陥が生じる反応等を意味する。
コア粒子101は、電極反応物質であるリチウムを吸蔵および放出することが可能であり、六方晶系の層状岩塩型構造を有する複合酸化物を含む。複合酸化物は、いわゆるリチウム遷移金属複合酸化物であり、具体的には、Liと、Coと、Ni、Fe、Pb、Mg、Al、K、Na、Ca、Si、Ti、Sn、V、Ge、Ga、B、As、Zr、MnおよびCrからなる群より選ばれる少なくとも1種の元素M1とを含む。リチウム遷移金属酸化物は、Coを主体としていることが好ましい。ここで、“Coを主体とする”とは、複合酸化物に含まれる金属元素の合計量に対するCoの原子比率が50%以上であることを意味する。
LixCoyM11-yO2 ・・・(1)
(式(1)中、M1はNi、Fe、Pb、Mg、Al、K、Na、Ca、Si、Ti、Sn、V、Ge、Ga、B、As、Zr、MnおよびCrからなる群より選ばれる少なくとも1種の元素を含む。xおよびyは、0.95≦x≦1.0、0<y<1を満たす。)
スピネル相102が島状または斑状等の形状でコア粒子101の表面の一部に存在することで、コア粒子101の表面の一部がスピネル相102から露出していてもよい。このようにコア粒子101の表面の一部が露出することで、この露出部分を介してリチウムイオンがスピネル相102により阻害されることなく、コア粒子101と電解液との間を移動することができる。したがって、抵抗の上昇を抑制し、サイクル特性をさらに向上することができる。
CoxM23-xO4・・・(2)
(但し、式(2)中、M2はNi、Fe、Pb、Mg、Al、K、Na、Ca、Si、Ti、Sn、V、Ge、Ga、B、As、Zr、MnおよびCrからなる群より選ばれる少なくとも1種の元素を含む。xは0<X<1を満たす。)
正極活物質粒子100は、S、PおよびFからなる群より選ばれる少なくとも1種の元素M2を含む化合物をさらに含むことが好ましい。このように正極活物質粒子100が少なくとも1種の元素M2を含む化合物をさらに含むことにより、特に長期保存時の性能低下や長期のサイクル特性を改善することができる。
少なくとも1種の元素M1が、規定の割合で正極活物質粒子100の表面に存在している。具体的には、正極活物質粒子100の表面におけるCo量と少なくとも1種の元素M1の総量との原子比(少なくとも1種の元素M1の総量/Co量)が、0.6以上1.3以下、好ましくは0.8以上1.1以下である。原子比(M1/Co)が0.6未満であると、正極活物質粒子100の表面に存在する元素M1が少なすぎ、結晶構造安定化の機能が低下するため、サイクル特性および保存特性を両立することができなくなる虞がある。一方、原子比(M1/Co)が1.3を超えると、正極活物質粒子100の表面に存在する元素M1が多すぎ、相対的にコバルト等の遷移金属が減少し、粒子の導電性が低下し、抵抗成分の増加となるため、サイクル特性が低下する虞がある。本明細書において、“正極活物質粒子100の表面”とは、正極活物質粒子100の最表面から深さ5nm以下の領域のことをいう。また、正極活物質粒子100の内部”とは、正極活物質粒子100の最表面から深さ5nmを超える領域のことをいう。
図2は、本発明の第1の実施形態に係る正極活物質のラマンスペクトルの一例を示す。正極活物質のラマンスペクトルにおいて、480cm-1近傍に六方晶系構造のEg振動モードのピークが観察され、590cm-1近傍に六方晶系構造のA1g振動モードのピークが観察される。Eg振動モードはO-Co-O bendingに帰属され、A1g振動モードはCo-O stretchingに帰属される。また、600cm-1以上700cm-1以下の範囲内にスピネル相102のA1g振動モードのピークが観察される。
本発明の第1の実施形態に係る正極活物質は、例えば以下のようにして作製される。まず、Liと、Coと、少なくとも1種の元素M1とを含み、六方晶系の層状岩塩型構造を有する複合酸化物粒子の粉末を作製する。続いて、作製した複合酸化物粒子の粉末と、炭酸リチウムと、酸化コバルトと、Ni含有化合物、Fe含有化合物、Pb含有化合物、Mg含有化合物、Al含有化合物、K含有化合物、Na含有化合物、Ca含有化合物、Si含有化合物、Ti含有化合物、Sn含有化合物、V含有化合物、Ge含有化合物、Ga含有化合物、B含有化合物、As含有化合物、Zr含有化合物、Mn含有化合物およびCr含有化合物からなる群より選ばれる少なくとも1種の化合物とを混合することにより混合物を得る。この際、最終的に得られる正極活物質粒子100の表面におけるCo量と少なくとも1種の元素M1の総量との原子比(少なくとも1種の元素M1の総量/Co量)が0.6以上1.3以下とるように、各材料の配合比を調整する。また、炭酸リチウムに代えて、リン酸リチウム、フッ化リチウムおよび硫化リチウムのうちの少なくとも1種を用いてもよい。次に、混合物を高速撹拌し、例えば空気気流下で熱処理したのち、微粉砕する。これにより、第1の実施形態に係る正極活物質が得られる。
第1の実施形態に係る正極活物質は、表面被覆型の正極活物質粒子100の粉末を含む。正極活物質粒子100は、コア粒子101と、コア粒子101の表面の少なくとも一部に存在するスピネル相102とを含む。コア粒子101は、六方晶系構造を有する複合酸化物を含む正極活物質粒子100を含む。上記複合酸化物が、Liと、Coと、Ni、Fe、Pb、Mg、Al、K、Na、Ca、Si、Ti、Sn、V、Ge、Ga、B、As、Zr、MnおよびCrからなる群より選ばれる少なくとも1種の元素M1とを含む。スピネル相102は、Liと、少なくとも1種の元素M1とを含む酸化物を含む。粒子表面におけるCo量と少なくとも1種の元素M1の総量との原子比(少なくとも1種の元素M1の総量/Co量)が、0.6以上1.3以下であり、ラマンスペクトルにおける六方晶系構造のA1g振動モードのピークの半値幅が、10cm-1以上17cm-1以下であり、ラマンスペクトルにおける六方晶系構造のA1g振動モードのピーク強度IA1g-Hと、六方晶系構造のEg振動モードのピーク強度IEgとのピーク強度比IA1g-H/IEgが、1.1以上1.9以下である。これにより、サイクル特性および保存特性を両立することができる。
本発明の第1の実施形態に係る正極活物質を用いて、種々の形状およびサイズの非水電解質二次電池(以下単に「電池」という。)を作製することが可能である。以下に、本発明の第1の実施形態に係る正極活物質を用いた電池の一例について説明する。
図3は、本発明の第2の実施形態に係る電池の構成の一例を示す。第2の実施形態に係る電池は、いわゆるラミネート型電池であり、正極リード11および負極リード12が取り付けられた電極体20をフィルム状の外装材10の内部に収容したものであり、小型化、軽量化および薄型化が可能となっている。
正極21は、例えば、正極集電体21Aと、正極集電体21Aの両面に設けられた正極活物質層21Bとを備える。正極集電体21Aは、例えば、アルミニウム箔、ニッケル箔またはステンレス箔等の金属箔により構成されている。正極活物質層21Bは、正極活物質を含む。正極活物質層21Bは、必要に応じてバインダーおよび導電剤のうちの少なくとも1種をさらに含んでいてもよい。
正極活物質は、上述した第1の実施形態に係る正極活物質である。
バインダーとしては、例えば、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、ポリアクリロニトリル、スチレンブタジエンゴムおよびカルボキシメチルセルロース等の樹脂材料、ならびにこれら樹脂材料を主体とする共重合体等からなる群より選ばれる少なくとも1種が用いられる。
導電剤としては、例えば、黒鉛、炭素繊維、カーボンブラック、ケッチェンブラックおよびカーボンナノチューブ等からなる群より選ばれる少なくとも1種の炭素材料が用いられる。なお、導電剤は導電性を有する材料であればよく、炭素材料に限定されるものではない。例えば、導電剤として金属材料または導電性高分子材料等を用いるようにしてもよい。
負極22は、例えば、負極集電体22Aと、負極集電体22Aの両面に設けられた負極活物質層22Bとを備える。負極集電体22Aは、例えば、銅箔、ニッケル箔またはステンレス箔等の金属箔により構成されている。
負極活物質としては、例えば、難黒鉛化性炭素、易黒鉛化性炭素、黒鉛、熱分解炭素類、コークス類、ガラス状炭素類、有機高分子化合物焼成体、炭素繊維または活性炭等の炭素材料が挙げられる。このうち、コークス類には、ピッチコークス、ニードルコークスまたは石油コークス等がある。有機高分子化合物焼成体というのは、フェノール樹脂やフラン樹脂等の高分子材料を適当な温度で焼成して炭素化したものをいい、一部には難黒鉛化性炭素または易黒鉛化性炭素に分類されるものもある。これら炭素材料は、充放電時に生じる結晶構造の変化が非常に少なく、高い充放電容量を得ることができると共に、良好なサイクル特性を得ることができるので好ましい。特に黒鉛は、電気化学当量が大きく、高いエネルギー密度を得ることができ好ましい。また、難黒鉛化性炭素は、優れたサイクル特性が得られるので好ましい。さらにまた、充放電電位が低いもの、具体的には充放電電位がリチウム金属に近いものが、電池の高エネルギー密度化を容易に実現することができるので好ましい。
バインダーとしては、正極活物質層21Bと同様のものを用いることができる。
導電剤としては、正極活物質層21Bと同様のものを用いることができる。
セパレータ23は、正極21と負極22とを隔離し、両極の接触による電流の短絡を防止しつつ、リチウムイオンを通過させるものである。セパレータ23は、例えば、ポリテトラフルオロエチレン、ポリオレフィン樹脂(ポリプロピレン(PP)またはポリエチレン(PE)等)、アクリル樹脂、スチレン樹脂、ポリエステル樹脂またはナイロン樹脂、または、これらの樹脂をブレンドした樹脂からなる多孔質膜によって構成されており、これらの2種以上の多孔質膜を積層した構造とされていてもよい。
電解液は、いわゆる非水電解液であり、有機溶媒(非水溶媒)と、この有機溶媒に溶解された電解質塩とを含んでいる。電解液が、電池特性を向上するために、公知の添加剤を含んでいてもよい。なお、電解液に代えて、電解液と、この電解液を保持する保持体となる高分子化合物とを含む電解質層を用いるようにしてもよい。この場合、電解質層は、ゲル状となっていてもよい。
上述の構成を有する電池では、充電を行うと、例えば、正極活物質層21Bからリチウムイオンが放出され、電解液を介して負極活物質層22Bに吸蔵される。また、放電を行うと、例えば、負極活物質層22Bからリチウムイオンが放出され、電解液を介して正極活物質層21Bに吸蔵される。
次に、本発明の第2の実施形態に係る電池の製造方法の一例について説明する。
正極21を次のようにして作製する。まず、例えば、正極活物質と、導電剤と、バインダーとを混合して正極合剤を調製し、この正極合剤をN-メチル-2-ピロリドン(NMP)等の溶剤に分散させてペースト状の正極合剤スラリーを作製する。次に、この正極合剤スラリーを正極集電体21Aに塗布し溶剤を乾燥させ、ロールプレス機等により圧縮成型することにより正極活物質層21Bを形成し、正極21を得る。
負極22を次のようにして作製する。まず、例えば、負極活物質と、バインダーとを混合して負極合剤を調製し、この負極合剤をN-メチル-2-ピロリドン等の溶剤に分散させてペースト状の負極合剤スラリーを作製する。次に、この負極合剤スラリーを負極集電体22Aに塗布し溶剤を乾燥させ、ロールプレス機等により圧縮成型することにより負極活物質層22Bを形成し、負極22を得る。
巻回型の電極体20を次のようにして作製する。まず、正極集電体21Aの一方の端部に正極リード11を溶接により取り付けると共に、負極集電体22Aの一方の端部に負極リード12を溶接により取り付ける。次に、正極21と負極22とをセパレータ23を介して扁平状の巻芯の周囲に巻き付けて、長手方向に多数回巻回したのち、最外周部に保護テープ24を接着して電極体20を得る。
外装材10により電極体20を次のようにして封止する。まず、電極体20を外装材10に挟み、一辺を除く外周縁部を熱融着して袋状とし、外装材10の内部に収納する。その際、正極リード11および負極リード12と外装材10との間に密着フィルム13を挿入する。なお、正極リード11、負極リード12にそれぞれ密着フィルム13を予め取り付けておいてもよい。次に、未融着の一辺から電解液を外装材10の内部に注入したのち、未融着の一辺を真空雰囲気下で熱融着して密封する。以上により、図3、図4に示した電池が得られる。
第2の実施形態に係る電池では、正極活物質層21Bが、第1の実施形態に係る正極活物質を含むので、サイクル特性および保存特性を両立することができる。特に高温環境下においてサイクル特性および保存特性を両立することができる。
第3の実施形態では、上述の第2の実施形態に係る電池を備える電子機器について説明する。
電子回路401は、例えば、CPU(Central Processing Unit)、周辺ロジック部、インターフェース部および記憶部等を備え、電子機器400の全体を制御する。
電池パック300は、組電池301と、充放電回路302とを備える。電池パック300が、必用に応じて組電池301および充放電回路302を収容する外装材(図示せず)をさらに備えるようにしてもよい。
(工程(1))
まず、市販の炭酸リチウム、酸化コバルト、水酸化アルミニウムおよび炭酸マグネシウムを、Li、Co、MgおよびAlのモル比がそれぞれ1.02:0.99:0.005:0.005となるように混合することにより、混合物を得た。次に、この混合物を空気中で1000℃、6時間焼成し、徐冷することにより、平均粒子径20μm、比表面積0.3m2/gの、Mg、Al含有LiCoO2粒子の粉末を得た。
まず、市販の炭酸リチウム、酸化コバルト、炭酸マグネシウム、水酸化アルミニウムおよび酸化チタンを、Li、Co、Mg、AlおよびTiのモル比がそれぞれ1.02:0.85:0.05:0.05:0.05となるように混合することにより、混合物を得た。次に、この混合物5質量%を、工程(1)で得られたLCO2粒子の粉末(母材)95質量%に添加し、高速攪拌機にて3時間処理したのち、空気気流下で800℃、3時間焼成し、ボールミルにて微粉砕した。これにより、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)における高速攪拌機での処理時間を2時間としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)における高速攪拌機での処理時間を5時間とした以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)における焼成温度を750℃とした以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)における焼成温度を850℃とした以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)におけるLi、Co、Mg、AlおよびTiのモル比をそれぞれ1.02:0.79:0.07:0.07:0.07としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)におけるLi、Co、Mg、AlおよびTiのモル比をそれぞれ1.02:0.91:0.03:0.03:0.03としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)において、市販の炭酸リチウム、酸化コバルト、水酸化アルミニウムおよび酸化チタンを、Li、Co、AlおよびTiのモル比がそれぞれ1.02:0.90:0.05:0.05となるように混合することにより、混合物を得たこと以外は実施例1と同様にして、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)において、市販の炭酸リチウム、酸化コバルト、炭酸マグネシウムおよび水酸化アルミニウムを、Li、Co、MgおよびAlのモル比がそれぞれ1.02:0.90:0.05:0.05となるように混合することにより、混合物を得たこと以外は実施例1と同様にして、MgおよびAlが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)において、市販の炭酸リチウム、酸化コバルト、炭酸マグネシウムおよび酸化チタンを、Li、Co、MgおよびTiのモル比がそれぞれ1.02:0.90:0.05:0.05となるように混合することにより、混合物を得たこと以外は実施例1と同様にして、MgおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)において、市販の炭酸リチウム、酸化コバルトおよび水酸化アルミニウムを、Li、CoおよびAlのモル比がそれぞれ1.02:0.95:0.05となるように混合することにより、混合物を得たこと以外は実施例1と同様にして、Alが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)において、市販の炭酸リチウム、酸化コバルトおよび酸化チタンを、Li、CoおよびTiのモル比をそれぞれ1.02:0.95:0.05となるように混合することにより、混合物を得たこと以外は実施例1と同様にして、Tiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)において、市販の炭酸リチウム、酸化コバルトおよび炭酸マグネシウムを、Li、CoおよびMgのモル比がそれぞれ1.02:0.95:0.05となるように混合することにより、混合物を得たこと以外は実施例1と同様にして、Mgが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)において炭酸リチウムに代えてリン酸リチウムを用いたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在し、かつPも表面に存在する正極活物質粒子の粉末を得た。
工程(2)において炭酸リチウムに代えてフッ化リチウムを用いたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在し、かつFも表面に存在する正極活物質粒子の粉末を得た。
工程(2)において炭酸リチウムに代えて硫化リチウムを用いたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在し、かつSも表面に存在する正極活物質粒子の粉末を得た。
工程(2)において、高速攪拌機で処理する際に、下記に示す方法で作製したLiAlMg含有酸化コバルトを1200ppm混合する以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
炭酸コバルト100質量部に対し、炭酸リチウムを50質量部、酸化マグネシウム1質量部、酸化アルミニウム1質量部相当量を混合したのち、空気気流下で800℃、3時間焼成し、ボールミルにて微粉砕し、LiMgAl含有酸化コバルトを合成した。得られた微粉末をXRD(X‐ray diffraction)により解析したところ、スピネル相を有することが確認された。
工程(1)において、市販の炭酸リチウムおよび酸化コバルトを、LiおよびCoのモル比がそれぞれ1.02:1.00となるように混合することにより、混合物を得た。また、工程(2)において、市販の炭酸リチウムおよび酸化コバルトを、LiおよびCoのモル比がそれぞれ1.02:1.00となるように混合することにより、混合物を得た。これら以外のことは実施例1と同様にして正極活物質粒子の粉末を得た。
工程(2)における高速攪拌機での処理時間を1時間としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)における高速攪拌機での処理時間を10時間としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)における焼成温度を700℃としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)における焼成温度を900℃としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)におけるLi、Co、Mg、AlおよびTiのモル比をそれぞれ1.02:0.80:0.1:0.1:0.1としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
工程(2)におけるLi、Co、Mg、AlおよびTiのモル比をそれぞれ1.02:0.98:0.01:0.01:0.01としたこと以外は実施例1と同様にして、Mg、AlおよびTiが高濃度で表面に存在する正極活物質粒子の粉末を得た。
以上のようにして得られた正極活物質粒子の粉末について、以下の評価を行った。
まず、測定装置としてアルバック・ファイ株式会社製の走査型X線光電子分光装置(Quantera SXM)を用い、以下の測定条件で測定を行った。
X線源:単色化Al-Kα(1486.6eV)
X線スポット径:100μm
次に、検出されたすべての元素のピーク面積より、アルバック・ファイ株式会社製提供の相対感度因子を用いて表面原子濃度を計算し、Co量に対する元素M1(Mg、AlおよびTiのうちの少なくとも1種の元素M1)の総量の原子比(M1の総量/Co量)を算出した。
まず、測定装置としてナノフォトン社製のRAMAN-11を用い、以下の測定条件でラマンスペクトルの測定を行った。
励起レーザー波長:532nm
励起レーザー出力:0.26mW (optical line shaping mode)
使用対物レンズ:50倍
NA:0.8
コンフォーカルスリット幅:100μm
次に、測定したラマンスペクトル(図2参照)において、六方晶系構造のA1g振動モードのピークの半値幅(FWHM)をGaussian fittingにより算出した。また、六方晶系構造のA1g振動モードのピーク強度IA1g-Hと六方晶系構造のEg振動モードのピーク強度IEgとのピーク強度比IA1g-H/IEgを算出した。さらに、ラマンスペクトルにおけるスピネル相のA1g振動モードのピーク強度IA1g-Sと、六方晶系構造のA1g振動モードのピーク強度IA1g-Hとのピーク強度比IA1g-S/IA1g-Hを算出した。
上述のようにして得られた正極活物質粒子の粉末を用いて、以下のようにして電池を作製した。
「サイクル維持率」(%)=(「500サイクル目の放電容量」/「初回放電容量」)×100(%)
まず、上述のサイクル特性評価の評価と同様にして、電池を作製した。続いて、作製した電池に対して、上述のサイクル特性評価にて初回放電容量を求めた場合と同様の充電条件で充電し、60℃の環境温度で14日間保存した。保存後、上述のサイクル特性評価にて初回放電容量を求めた場合と同様の放電条件で放電し、60℃14日間保存後の放電容量を測定し、初回放電容量に対する保存維持率を以下の式により求めた。なお、初回放電容量は、上述のサイクル特性評価と同様にして求めた。
「保存維持率」(%)=(「60℃14日間保存後の放電容量」/「初回放電容量」)×100(%)
次に、保存後の電池を解体し、負極を取り出した。続いて、取り出した負極を15mlの塩酸1M中にて15分間煮沸し、その溶液を濾過し、シーケンシャル型ICP発光分光分析装置(日立ハイテクサイエンス製、SPS3100)で溶液中に含まれるCoの濃度を測定した。そして、以下の式より、保存時におけるCoの溶出量を測定した。
Co溶出量=(Co濃度)/(正極に含まれる活物質重量)
次に、測定した各実施例および各比較例のCo溶出量を、実施例5のCo溶出量を100とする相対値に変換した。
実施例1~14の正極活物質は、以下の(1)から(4)の構成を備えるため、高温環境下において高いサイクル維持率、高い保存維持率およびCo溶出の低減を実現することができる。すなわち、高温環境下においてサイクル特性および保存特性を両立することができる。
(1)リチウム遷移金属複合酸化物が、Liと、Coと、Mg、AlおよびTiからなる群より選ばれる少なくとも1種の元素M1とを含み、当該少なくとも1種の元素M1が、正極活物質粒子の表面に存在する。
(2)粒子表面におけるCo量と上記少なくとも1種の元素M1の総量との原子比(上記少なくとも1種の元素M1の総量/Co量)が、0.6以上1.3以下である。
(3)ラマンスペクトルにおける六方晶系構造のA1g振動モードのピークの半値幅が、10cm-1以上17cm-1以下である。
(4)ラマンスペクトルにおける六方晶系構造のA1g振動モードのピーク強度IA1g-Hと、六方晶系構造のEg振動モードのピーク強度IEgとのピーク強度比IA1g-H/IEgが、1.1以上1.9以下である。
(5)ラマンスペクトルにおけるスピネル相のA1g振動モードのピーク強度IA1g-Sと、六方晶系構造のA1g振動モードのピーク強度IA1g-Hとのピーク強度比IA1g-S/IA1g-Hが、0.04以下である。
11 正極リード
12 負極リード
13 密着フィルム
20 電極体
21 正極
21A 正極集電体
21B 正極活物質層
22 負極
22A 負極集電体
22B 負極活物質層
23 セパレータ
24 保護テープ
100 正極活物質粒子
101 コア粒子
102 スピネル相
300 電池パック
400 電子機器
Claims (7)
- 六方晶系構造を有する複合酸化物を含む正極活物質粒子を含み、
前記複合酸化物が、Liと、Coと、Ni、Fe、Pb、Mg、Al、K、Na、Ca、Si、Ti、Sn、V、Ge、Ga、B、As、Zr、MnおよびCrからなる群より選ばれる少なくとも1種の元素M1とを含み、
前記少なくとも1種の元素M1が、前記正極活物質粒子の表面に存在し、
前記正極活物質粒子の表面におけるCo量と前記少なくとも1種の元素M1の総量との原子比(前記少なくとも1種の元素M1の総量/Co量)が、0.6以上1.3以下であり、
ラマンスペクトルにおける六方晶系構造のA1g振動モードのピークの半値幅が、10cm-1以上17cm-1以下であり、
ラマンスペクトルにおける六方晶系構造のA1g振動モードのピーク強度IA1g-Hと、六方晶系構造のEg振動モードのピーク強度IEgとのピーク強度比IA1g-H/IEgが、1.1以上1.9以下である正極活物質。 - 前記正極活物質粒子が、前記少なくとも1種の元素M1を含有するスピネル相をさらに含み、
前記スピネル相が、前記正極活物質粒子の表面に存在する請求項1に記載の正極活物質。 - ラマンスペクトルにおけるスピネル相のA1g振動モードのピーク強度IA1g-Sと、六方晶系構造のA1g振動モードのピーク強度IA1g-Hとのピーク強度比IA1g-S/IA1g-Hが、0.04以下である請求項2に記載の正極活物質。
- 前記元素M1が、Mg、AlおよびTiからなる群より選ばれる少なくとも1種を含む請求項1から3のいずれか1項に記載の正極活物質。
- 前記正極活物質粒子が、元素M2の化合物をさらに含み、
前記元素M2が、S、PおよびFからなる群より選ばれる少なくとも1種を含む請求項1から4のいずれか1項に記載の正極活物質。 - 前記複合酸化物が、下記の式(1)で表される平均組成を有する請求項1から5のいずれか1項に記載の正極活物質。
LixCoyM11-yO2 ・・・(1)
(式(1)中、M1はNi、Fe、Pb、Mg、Al、K、Na、Ca、Si、Ti、Sn、V、Ge、Ga、B、As、Zr、MnおよびCrからなる群より選ばれる少なくとも1種の元素を含む。xおよびyは、0.95≦x≦1.0、0<y<1を満たす。) - 請求項1から6のいずれか1項に記載の前記正極活物質を含む正極と、
負極と、
電解質と
を備える電池。
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH076753A (ja) * | 1993-06-15 | 1995-01-10 | Toray Ind Inc | 電極およびその製造方法、およびその電極を用いた二次電池 |
JPH11242959A (ja) * | 1997-12-26 | 1999-09-07 | Sanyo Electric Co Ltd | リチウム二次電池 |
JP2005044785A (ja) | 2003-07-24 | 2005-02-17 | Samsung Sdi Co Ltd | 正極活物質及びこれを利用したリチウム二次電池 |
JP2016081716A (ja) * | 2014-10-16 | 2016-05-16 | 日立金属株式会社 | リチウムイオン二次電池用正極活物質及びその製造方法並びにリチウムイオン二次電池 |
US20180079655A1 (en) * | 2016-09-21 | 2018-03-22 | Apple Inc. | Surface stabilized cathode material for lithium ion batteries and synthesizing method of the same |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20080074227A (ko) * | 2006-01-20 | 2008-08-12 | 닛코 킨조쿠 가부시키가이샤 | 리튬 니켈 망간 코발트 복합 산화물 및 리튬 이차 전지 |
JP2011100663A (ja) * | 2009-11-06 | 2011-05-19 | Sony Corp | 非水電解質電池 |
JP2012054093A (ja) * | 2010-09-01 | 2012-03-15 | Sharp Corp | 正極活物質およびこれを含む正極を備える非水系二次電池 |
JP2016033901A (ja) * | 2014-07-31 | 2016-03-10 | ソニー株式会社 | 正極活物質、正極および電池 |
JP2016033902A (ja) * | 2014-07-31 | 2016-03-10 | ソニー株式会社 | 正極活物質、正極および電池 |
-
2019
- 2019-06-19 JP JP2020525773A patent/JP6992897B2/ja active Active
- 2019-06-19 CN CN201980041486.4A patent/CN112313821B/zh active Active
- 2019-06-19 EP EP19823078.1A patent/EP3813164A4/en active Pending
- 2019-06-19 WO PCT/JP2019/024321 patent/WO2019244936A1/ja active Application Filing
-
2020
- 2020-12-15 US US17/122,127 patent/US11973216B2/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH076753A (ja) * | 1993-06-15 | 1995-01-10 | Toray Ind Inc | 電極およびその製造方法、およびその電極を用いた二次電池 |
JPH11242959A (ja) * | 1997-12-26 | 1999-09-07 | Sanyo Electric Co Ltd | リチウム二次電池 |
JP2005044785A (ja) | 2003-07-24 | 2005-02-17 | Samsung Sdi Co Ltd | 正極活物質及びこれを利用したリチウム二次電池 |
JP2016081716A (ja) * | 2014-10-16 | 2016-05-16 | 日立金属株式会社 | リチウムイオン二次電池用正極活物質及びその製造方法並びにリチウムイオン二次電池 |
US20180079655A1 (en) * | 2016-09-21 | 2018-03-22 | Apple Inc. | Surface stabilized cathode material for lithium ion batteries and synthesizing method of the same |
Non-Patent Citations (1)
Title |
---|
See also references of EP3813164A4 |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2022116279A (ja) * | 2018-08-03 | 2022-08-09 | 株式会社半導体エネルギー研究所 | リチウムイオン二次電池の作製方法 |
JP7344341B2 (ja) | 2018-08-03 | 2023-09-13 | 株式会社半導体エネルギー研究所 | リチウムイオン二次電池の作製方法 |
WO2023209475A1 (ja) * | 2022-04-25 | 2023-11-02 | 株式会社半導体エネルギー研究所 | 正極活物質、正極、二次電池、電子機器および車両 |
WO2024084368A1 (ja) * | 2022-10-21 | 2024-04-25 | 株式会社半導体エネルギー研究所 | 二次電池、電子機器および車両 |
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US20210104727A1 (en) | 2021-04-08 |
JP6992897B2 (ja) | 2022-01-13 |
CN112313821B (zh) | 2024-05-07 |
EP3813164A1 (en) | 2021-04-28 |
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