WO2014061579A1 - Method for producing positive electrode active material for lithium secondary battery, and active material precursor powder used therein - Google Patents

Method for producing positive electrode active material for lithium secondary battery, and active material precursor powder used therein Download PDF

Info

Publication number
WO2014061579A1
WO2014061579A1 PCT/JP2013/077742 JP2013077742W WO2014061579A1 WO 2014061579 A1 WO2014061579 A1 WO 2014061579A1 JP 2013077742 W JP2013077742 W JP 2013077742W WO 2014061579 A1 WO2014061579 A1 WO 2014061579A1
Authority
WO
WIPO (PCT)
Prior art keywords
powder
active material
lithium
raw material
particles
Prior art date
Application number
PCT/JP2013/077742
Other languages
French (fr)
Japanese (ja)
Inventor
昌平 横山
小林　伸行
幸信 由良
Original Assignee
日本碍子株式会社
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 日本碍子株式会社 filed Critical 日本碍子株式会社
Priority to JP2014542104A priority Critical patent/JP5830178B2/en
Publication of WO2014061579A1 publication Critical patent/WO2014061579A1/en

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
    • H01M4/36—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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/006—Compounds containing, besides nickel, two or more other elements, with the exception of oxygen or hydrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese of the type [MnO2]n-, e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/30—Particle morphology extending in three dimensions
    • C01P2004/32—Spheres
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/11—Powder tap density
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/14—Pore volume
    • 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 method for producing a positive electrode active material for a lithium secondary battery having a layered rock salt structure and an active material precursor powder used therefor.
  • Patent Document 1 Japanese Patent Laid-Open No. 5-226004
  • Patent Document 2 Japanese Patent Laid-Open No. 2003-132877
  • lithium ions Li +
  • the diffusion of lithium ions (Li + ) therein is performed in the in-plane direction of the (003) plane (that is, any direction in a plane parallel to the (003) plane). It is known that lithium ions enter and exit from crystal planes other than the (003) plane (for example, the (101) plane or the (104) plane).
  • the crystal plane (surface other than the (003) plane, for example, the (101) plane or the (104) plane) on which lithium ions can be satisfactorily entered and exited, is brought into contact with the electrolyte. Attempts have been made to improve the battery characteristics of lithium secondary batteries by exposing them (see, for example, Patent Document 3 (International Publication No. 2010/074304)).
  • this type of positive electrode active material is known in which pores (also referred to as pores or voids) are formed therein (for example, Patent Document 4 (Japanese Patent Laid-Open No. 2002-75365)). 5 (Japanese Patent Laid-Open No. 2004-083388) and Patent Document 6 (Japanese Patent Laid-Open No. 2009-117241).
  • a pore-forming agent void forming material
  • void forming material a particulate or fibrous substance made of an organic synthetic resin, which is decomposed (mainly evaporated or carbonized) in a temporary firing step.
  • the pore-forming agent is reduced in order to increase the volume energy density and the amount of voids is reduced, the voids are difficult to communicate with each other, and closed pores are formed. May not be able to enter the pores, which may reduce the output characteristics. Therefore, it is advantageous if a desired porosity and average pore diameter can be realized without using such a pore-forming agent.
  • the present inventors now use a pore-forming agent by granulating and spheroidizing a substantially spherical secondary particle raw material powder to include voids (hereinafter sometimes referred to as “tertiary granulation”).
  • a positive electrode active material having a desired porosity and a high open pore ratio can be produced, which provides high battery characteristics.
  • an object of the present invention is to produce a positive electrode active material having a desired porosity and a high open pore ratio, which provides high battery characteristics without using a pore-forming agent.
  • a method for producing a positive electrode active material for a lithium ion battery Ni 1-y M y (OH) 2 (where 0 ⁇ y ⁇ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles.
  • Preparing a hydroxide raw material powder or an aggregate thereof Using the hydroxide raw material powder or pulverizing the aggregate to prepare a slurry containing the hydroxide raw material powder; and Producing a substantially spherical granulated powder using the slurry; Mixing the lithium compound with the granulated powder to obtain a lithium mixed powder; Firing the lithium mixed powder to react the granulated powder with a lithium compound, thereby obtaining a positive active material for a lithium secondary battery having open pores; A method comprising is provided.
  • a method for producing a positive electrode active material for a lithium ion battery comprising: Ni 1-y M y (OH) 2 (where 0 ⁇ y ⁇ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles.
  • Preparing a hydroxide raw material powder or an aggregate thereof Using the hydroxide raw material powder or pulverizing the aggregate to prepare a slurry containing the hydroxide raw material powder and lithium hydroxide; Producing a substantially spherical granulated powder using the slurry; Calcining the granulated powder to react the granulated powder with the lithium hydroxide, thereby obtaining a positive electrode active material for a lithium secondary battery having open pores;
  • a method comprising is provided.
  • an active material precursor powder used for manufacturing a positive electrode active material for a lithium ion battery Ni 1-y M y (OH) 2 (where 0 ⁇ y ⁇ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles.
  • Hydroxide raw material powder A raw material having the same composition as the hydroxide raw material powder and a particle size smaller than that of the hydroxide raw material powder, in an amount of 0 to 25% by mass or less based on the total amount of the hydroxide raw material powder and the raw material fine particles Fine particles, A water-soluble lithium compound interposed between the secondary particles and / or between the secondary particles and the raw material fine particles;
  • the active material precursor powder is deagglomerated in water by ultrasonic irradiation, the proportion of particles having a particle size of 1.0 ⁇ m or less is 0 to 40% on a volume basis.
  • An active material precursor powder having a reference D50 average particle size is provided.
  • Primary particles refers to unit particles that do not contain crystal grain boundaries inside.
  • secondary particles those in which primary particles are aggregated and those in which a plurality (large number) of single-crystal primary particles are aggregated are referred to as “secondary particles”.
  • the term “tertiary particles” is sometimes used in the present specification, but this is a term used for convenience to express particles of agglomerated powder in which a large number of secondary particles are aggregated. The above is included in the category of “secondary particles”.
  • the “average particle diameter” is an average value of particle diameters.
  • the “diameter” is typically a diameter of the sphere when the particle is assumed to be a sphere having the same volume or the same cross-sectional area.
  • the “average value” is preferably calculated on the basis of the number.
  • the average particle diameter of the primary particles can be determined, for example, by observing the surface or cross section of the secondary particles with a scanning electron microscope (SEM).
  • SEM scanning electron microscope
  • the average particle size of the secondary particles is a volume-based D50 average particle measured using water as a dispersion medium using a laser diffraction / scattering particle size distribution analyzer (for example, model number “MT3000-II” manufactured by Nikkiso Co., Ltd.). It is evaluated by the diameter (median diameter).
  • “Voidage” is the volume ratio of voids (including pores: including open pores and closed pores) in the positive electrode active material of the present invention. “Porosity” is sometimes referred to as “porosity”. This “porosity” is calculated from, for example, the bulk density and the true density. “Open pores” are pores communicating with the outside among the pores. “Closed pores” are pores which are not communicated with the outside among the pores.
  • Open pore ratio is the ratio of open pores communicating with outside air in all pores in the secondary particles. That is, the open pore ratio is (area of open pore portion) / (area of open pore portion + area of closed pore portion). Since the open pores communicate with the outside, the resin can be injected from the outside, and the closed pores do not communicate with the outside, so the resin cannot be injected from the outside. Therefore, the open pore ratio is determined by performing resin filling in which a resin is injected into the gap (and thus in the open pore) while sufficiently removing the air present in the open pore using a vacuum impregnation device.
  • the impregnated portion is treated as an open pore
  • the portion of the void not impregnated with resin is treated as a closed pore
  • these areas are obtained from, for example, image processing of a SEM photograph of the cross-section of the secondary particle, , (Area of open pore portion) / (area of open pore portion + area of closed pore portion).
  • Average open pore diameter means the average pore diameter of the open pores, and is the average value of the diameters of the open pores in the secondary particles. This “diameter” is typically the diameter of the spherical shape when the open pores are assumed to be spherical with the same volume or the same cross-sectional area. The “average value” is preferably calculated on a volume basis. Further, the average open pore diameter can be determined by a known method such as image processing of an SEM photograph of the cross section of the secondary particle or mercury intrusion method.
  • “Tap density” is an increased bulk density obtained after mechanically tapping a container containing a powder sample.
  • the tap density is obtained by mechanically tapping a measuring graduated cylinder or container containing a powder sample.
  • the tap density is measured by measuring the initial volume or mass of the powder and then mechanically tapping the measuring graduated cylinder or container and reading the volume or mass until almost no change in volume or mass is observed. .
  • Press density is a bulk density obtained when a powder sample is formed into a tablet with a constant press pressure in a mold or the like.
  • the present invention of the positive electrode active material for a lithium secondary battery a method for producing a cathode active material for a lithium secondary battery having a layered rock salt structure.
  • “Layered rock salt structure” means a crystal structure in which lithium layers and transition metal layers other than lithium are alternately stacked with oxygen layers in between (typically ⁇ -NaFeO 2 type structure: cubic rock salt type structure) [111] A structure in which transition metals and lithium are regularly arranged in the axial direction.
  • the method of the present invention produces a hydroxide raw material powder comprising substantially spherical secondary particles in which a large number of primary particles are aggregated, wherein at least a part of the primary particles are arranged outward from the center of the secondary particles.
  • the slurry containing the hydroxide raw material powder is used to produce a substantially spherical granulated powder containing voids, which is mixed with a lithium compound and then subjected to firing to cause the granulated powder to react with the lithium compound. Comprising.
  • the substantially spherical secondary particle raw material of the raw material powder is granulated and spheroidized (tertiary granulated) so as to include voids, without using a pore forming agent.
  • a positive electrode active material having a desired porosity and a high open pore ratio can be produced, which provides high battery characteristics.
  • an aqueous metal element solution, an aqueous caustic solution, and an ammonium ion supplier are continuously supplied into a tank adjusted in pH and temperature while controlling the concentration and flow rate.
  • a hydroxide raw material powder composed of substantially spherical secondary particles in which a large number of primary particles are aggregated and in which at least a part of the primary particles are arranged outward from the center of the secondary particles is produced.
  • a slurry containing raw material secondary particles is prepared and dried by spray drying or the like to obtain a substantially spherical granulated powder.
  • the granulated powder thus obtained can be expressed as a tertiary particle powder in that many secondary particles are aggregated.
  • a large number of gaps are formed between the particles of the raw material secondary particle powder constituting the granulated powder due to the substantially spherical shape of the raw material powder.
  • a large number of gaps provide a large number of voids that are easily communicated with the outside of the positive electrode active material as a fired body, and open pores are easily formed even when the amount of voids is reduced.
  • a method of forming voids by utilizing melting or vaporization of the pore-forming agent during firing or calcination by incorporating a pore-forming agent is also conceivable, but in that case, it is necessary to increase the volume energy density. If the amount of voids is reduced by reducing the amount of the pore agent, there is a problem in that the voids are difficult to communicate with each other and closed pores are formed, so that the output characteristics are deteriorated because the electrolyte and the conductive additive cannot enter the pores. Further, although pores can be formed by adjusting the firing temperature or the like, there is a problem that closed pores are formed in a region where the amount of voids is small.
  • the open pores are not through-holes (there is only one entrance / exit to the surface), and it is difficult for the gas in the pores to escape when the electrolyte is injected. There was also a problem that it was difficult to penetrate.
  • the pores derived from the pore-forming agent are three-dimensionally formed by suppressing densification during firing and forming fine pores (for example, 0.1 ⁇ m or less) between the primary particles.
  • Ni 1-y M y (OH) 2 (where 0 ⁇ y ⁇ 0.5, M is Co, Al, Mg, Mn, Ti , Fe, Cr, Zn, and Ga, at least one metal element selected from the group consisting of secondary particles in which a large number of primary particles are aggregated, and at least part of the primary particles are secondary.
  • a hydroxide raw material powder or an aggregate thereof is prepared, which is arranged radially outward from the center of the particle.
  • the preferred metal element M is at least one or two metal elements selected from the group consisting of Co, Al, Mg and Mn, more preferably Al.
  • Mg and Mn and at least one selected from the group consisting of Co and Co, and particularly preferred combinations of metal elements M are Co and Al, or Co and Mn.
  • a predetermined element such as Al may not be included or made insufficient in the hydroxide raw material powder, and may be added in any subsequent step.
  • it is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga and is not included in the hydroxide raw material powder or hydroxide raw material powder
  • a compound for example, an oxide, a hydroxide and a hydrate thereof
  • the slurrying step is more preferable because the additive element compound can be easily mixed.
  • a part of the metal element M may be added at any stage.
  • a part of the metal element M added in any subsequent step is not a main additive element (for example, Co or Mn) but a small amount of additive element (for example, an element other than Co and Mn). This is because, when producing a hydroxide raw material powder that is a composite hydroxide, control of the particle shape and composition becomes easier when the number of types of elements is smaller.
  • the type of the metal element M is reduced to only the main additive element (for example, Co or Mn) to facilitate the control of the particle shape and composition, while the hydroxide raw material powder is prepared.
  • the main additive element for example, Co or Mn
  • an additive element for example, an element other than Co and Mn
  • the hydroxide raw material powder preferably has a tap density of 1.40 g / cc or more, more preferably 1.5 g / cc or more, and still more preferably 1.6 g / cc or more.
  • the higher the tap density the larger the difference in density between the voids and the particles in the tertiary particle powder described later, so that a high open pore ratio can be achieved even with a small porosity, but at 1.9 g / cc or less. It is realistic.
  • the hydroxide raw material powder preferably has a volume-based D50 average particle size of 1 to 5 ⁇ m as a secondary particle size, more preferably 2 to 4 ⁇ m, and still more preferably 2 to 3 ⁇ m.
  • the powder having a secondary particle size in the above range is composed of secondary particles having a volume-based D50 average particle size of 5 ⁇ m or more in which many primary particles are aggregated, and at least a part of the primary particles is outward from the center of the secondary particles It is also possible to use a lightly pulverized hydroxide raw material powder arranged radially toward the surface.
  • agglomerates of hydroxide raw material powder having the radial orientation described above may be used, and such agglomerates preferably have a volume-based D50 average particle size of 5 to 30 ⁇ m, more preferably 10 to 20 ⁇ m. It is.
  • Such a hydroxide raw material powder can be produced according to a known technique (see, for example, Patent Documents 3 and 4). For example, a method in which a nickel salt aqueous solution, a metal element M-containing aqueous solution, a caustic alkaline aqueous solution, and an ammonium ion supplier are continuously supplied and controlled while controlling the concentration and flow rate in a tank adjusted in pH and temperature. Is mentioned. At this time, in order to satisfy the tap density and the D50 average particle diameter, it is preferable that the pH in the tank is 10.0 to 12.0 and the temperature is 40 to 70 ° C.
  • This slurry is formed using the said hydroxide raw material powder or aggregate.
  • This slurry can be prepared, for example, by mixing a hydroxide raw material powder (substantially spherical secondary particles) with a dispersion medium such as water, and agglomeration of the hydroxide raw material powder having the radial orientation described above.
  • a hydroxide raw material powder substantially spherical secondary particles
  • a dispersion medium such as water
  • raw material fine particles having a diameter smaller than that of the raw material powder may be mixed with the raw material powder.
  • the raw material fine particles preferably have the same composition as the hydroxide raw material powder, and may be obtained by pulverizing the hydroxide raw material powder, or prepared separately from the hydroxide raw material powder. It may be.
  • the raw material fine particles may have a radial orientation similar to that of the hydroxide raw material powder, but may not have an orientation.
  • the porosity and the void diameter can be appropriately changed by controlling the particle size ratio and the mixing ratio of the raw material powder and the raw material fine particles in the slurry.
  • the raw material fine particles have high cohesion, the granulated powder can be made difficult to break.
  • the volume-based D50 average particle diameter of the raw material fine particles is preferably 10 nm to 700 nm, and more preferably 50 nm to 500 nm.
  • the ratio of the raw material fine particles to the total amount of the raw material powder and the raw material fine particles is preferably 25% by mass or less, more preferably 20% by mass or less.
  • a binder or a dispersant may or may not be added.
  • a preferred slurry is an aqueous slurry containing water as a dispersion medium.
  • the water-soluble lithium compound not only functions as a lithium source, but can also function as a binder for binding secondary particles of the hydroxide raw material powder to form tertiary particles in the subsequent granulation step. Therefore, the use of a water-soluble lithium compound in an aqueous slurry makes it easy to stably obtain a granulated powder having a desired particle size, and it is possible to eliminate the need for a subsequent lithium mixing step if necessary. .
  • the use of an organic binder can be eliminated, a degreasing process for eliminating the organic binder can be eliminated.
  • the water-soluble lithium compound include lithium hydroxide, lithium nitrate, lithium chloride, lithium oxide, and lithium peroxide. More preferably, the binder effect is high, the reactivity is high, and lithium can be easily introduced. In terms of lithium hydroxide.
  • the aqueous slurry preferably contains a water-soluble lithium compound in an amount of 0.01 to 0.20 in terms of a molar ratio of Li / (Ni + M), more preferably 0.02 to 0.15, and even more preferably. Is 0.04 to 0.10.
  • a molar ratio of Li / (Ni + M) Li / (Ni + M)
  • the capacity increases in battery characteristics.
  • the reactivity with the water-soluble lithium compound added in the above range is improved. That is, when the Li / (Ni + M) ratio is 0.01 or more, lithium is also present in the granulated powder in advance, so that lithium can be sufficiently supplied to the reaction at the time of firing, whereby the active material It is considered that it is difficult to form a lithium-deficient region inside.
  • Li / (Ni + M) ratio is 0.10% or less, a gas that is generated during the reaction of the water-soluble lithium compound and can stay in the granulated powder (in the case of lithium hydroxide, water vapor is It is considered that the amount of generation) is reduced to suppress the relative decrease in the concentration of oxygen necessary for the reaction, thereby making it difficult to form a region deficient in oxygen.
  • it is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn, and Ga, and is not included in the hydroxide raw material powder or hydroxylated.
  • a compound of an element lacking in the raw material powder may be added to the slurry.
  • a substantially spherical granulated powder containing voids can be obtained as a tertiary granulated powder.
  • the particle size of the granulated powder is a direct factor that determines the average particle size of the positive electrode active material particles, and is appropriately set according to the intended use of the particles. Tap density, press density, electrode film thickness In view of the above, the volume-based D50 average particle diameter is generally 5 to 40 ⁇ m, preferably 7 to 40 ⁇ m.
  • the drying / granulation method is not particularly limited as long as the raw material powder is filled and formed into a substantially spherical shape.
  • the atmosphere at the time of drying is not particularly limited, and may be an air atmosphere or an inert gas atmosphere.
  • nitrogen, argon, etc. It is preferable to use an inert gas atmosphere. This is because it is liable to react with lithium compounds in the firing step (lithium introduction step), because lithium carbonate, which is inferior in reactivity due to carbon dioxide in the air, can be precipitated when spray drying is performed in the air. This is because it may take time.
  • the added water-soluble lithium compound may precipitate between secondary particles constituting the granulated powder and function as a binder.
  • the granulated powder as the tertiary powder obtained in this manner is an active material precursor powder, and may be directly subjected to the subsequent lithium mixing step (can be omitted in some cases) and the firing step (lithium introduction step). Alternatively, it may be traded as an active material precursor powder or as a mixed powder with a lithium compound under the premise that the subsequent process is performed by the purchaser.
  • the granulated powder is mixed with a lithium compound to form a lithium mixed powder.
  • the lithium compound any lithium-containing compound that can finally give the composition LiMO 2 of the positive electrode active material can be used, and preferable examples include lithium hydroxide and lithium carbonate.
  • the pulverized powder is preferably mixed with the lithium compound by a method such as dry mixing or wet mixing.
  • the average particle size of the lithium compound is not particularly limited, but is preferably 0.1 to 5 ⁇ m from the viewpoint of ease of handling and reactivity from the viewpoint of hygroscopicity. In order to increase the reactivity, the lithium amount may be excessive by about 0.5 to 40 mol%.
  • the calcination temperature is preferably 400 ° C to 1000 ° C. When the temperature is 400 ° C. or higher, a sufficient thermal decomposition effect can be obtained. On the other hand, when the temperature is 1000 ° C. or lower, rapid progress of grain growth can be suppressed, and a decrease in reactivity with lithium in the firing step can be avoided.
  • the calcination atmosphere is not particularly limited, and may be an air atmosphere or an oxygen atmosphere.
  • it is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn, and Ga, and is not included in the hydroxide raw material powder or hydroxylated.
  • a compound of an element lacking in the raw material powder may be added to the granulated powder.
  • water-soluble lithium compound when used as a binder, it is possible to eliminate the lithium mixing step. In this case, all the required amount of water-soluble lithium compound may be added to the aqueous slurry in the slurrying step. However, a necessary amount of a part of the water-soluble lithium compound may be added to the aqueous slurry, and the remaining insufficient amount of the water-soluble lithium compound may be compensated in the lithium mixing step.
  • Firing step (introducing lithium)
  • the lithium mixed powder is fired to react the granulated powder with a lithium compound, thereby obtaining a positive electrode active material for a lithium secondary battery having open pores.
  • lithium is introduce
  • firing can be performed by putting a sheath containing the mixture before firing into a furnace. By this firing, the synthesis of the positive electrode active material, the sintering of the particles, and the grain growth are performed, and at the same time, open pores due to the gaps between the substantially spherical raw material powder secondary particles are formed.
  • the firing temperature is preferably 600 ° C. to 1100 ° C. Within this range, grain growth is sufficient, and the desired composition can be easily realized by suppressing decomposition of the positive electrode active material and volatilization of lithium.
  • the firing time is preferably 1 to 50 hours, and if it is within this range, excessive increase in energy consumed for firing can be prevented.
  • the temperature may be held at a temperature lower than the firing temperature (for example, 400 to 600 ° C.) for 1 to 20 hours. Since lithium is melted through the temperature holding step, the reactivity can be increased. The same effect can be obtained by adjusting the temperature increase rate in a certain temperature range (for example, 400 to 600 ° C.) in this firing (lithium introduction) step.
  • the firing atmosphere must be set appropriately so that decomposition does not proceed during firing.
  • firing is preferably performed in an atmosphere having a high oxygen partial pressure.
  • crushing and classification may be appropriately performed for the purpose of releasing adhesion and aggregation between the positive electrode active material particles or adjusting the average particle diameter of the positive electrode active material particles.
  • post-heat treatment may be performed at 100 to 400 ° C. in the positive electrode material active material after firing or after being crushed or classified.
  • the surface layer of the primary particles can be modified, thereby improving the rate characteristics and output characteristics.
  • the positive electrode active material may be subjected to a water washing treatment after firing or after being crushed or classified. By performing this water washing treatment step, the unreacted lithium raw material remaining on the surface of the positive electrode active material powder or the lithium carbonate produced by the adsorption of moisture and carbon dioxide in the atmosphere on the surface of the positive electrode active material powder is removed. Thereby, the high-temperature storage characteristics (especially gas generation suppression) are improved.
  • Positive electrode active material for lithium secondary battery According to the production method of the present invention described above, a positive electrode active material for a lithium secondary battery having a layered rock salt structure having voids with a high open pore ratio that provides high battery characteristics can be obtained. .
  • secondary particles composed of a large number of primary particles form tertiary particles having a porosity of 1 to 30% and an open pore ratio of 50% or more. . By making the porosity within this range, the effect of improving the charge / discharge characteristics can be obtained without impairing the capacity.
  • the open pore ratio in the positive electrode active material particles is preferably 50% or more, more preferably 60% or more, still more preferably 70%, particularly preferably 80% or more, and most preferably 90% or more. It is. Thus, since an open pore ratio is so high that it is preferable, an upper limit is not set in particular. By increasing the open pore ratio with a porosity in such a range, the electrolyte solution easily penetrates into the tertiary particles through the open pores, so that the ion conductivity is improved and at the same time, there are many portions other than the open pores.
  • lithium cobaltate (LiCoO 2 ) can be typically used.
  • a solid solution containing nickel or manganese in addition to cobalt as the lithium composite oxide constituting the positive electrode active material of the present invention.
  • the lithium composite oxide constituting the positive electrode active material of the present invention the following composition formula: Li x Ni 1-z M z O 2 (Wherein 0.96 ⁇ x ⁇ 1.09, 0 ⁇ z ⁇ 0.5) (where 0 ⁇ y ⁇ 0.5, M is Co, Al, Mg, Mn, Ti, Fe, Cr, Those represented by at least one metal element selected from the group consisting of Zn and Ga are preferably usable.
  • a preferable value of x is 0.98 to 1.06, and more preferably 1.00 to 1.04.
  • a preferable value of z is 0.15 to 0.4, and more preferably 0.15 to 0.25.
  • Preferred metal element M is at least one or two metal elements selected from the group consisting of Co, Al, Mg and Mn, more preferably at least one selected from the group consisting of Al, Mg and Mn.
  • a particularly preferred combination of metal elements M containing Co is Co and Al, or Co and Mn.
  • the surface of the positive electrode active material contains a compound containing a metal element not included in the active material, for example, a transition metal that can take an expensive number such as W, Mo, Nb, Ta, Re, etc. May be present.
  • a compound may be a compound of a transition metal capable of taking an expensive number such as W, Mo, Nb, Ta, Re, and Li.
  • the compound containing a metal element may be dissolved in the positive electrode active material or may exist as the second phase. By doing so, it is considered that the interface between the positive electrode active material and the non-aqueous electrolyte is modified, the charge transfer reaction is promoted, and the output characteristics and rate characteristics are improved.
  • lithium compound may be added to the raw material powder so that lithium is in an excess of 0.1 to 40 mol%.
  • low melting point oxide bismuth oxide, vanadium oxide, etc.
  • low melting point glass borosilicate glass, etc.
  • lithium fluoride lithium chloride boron oxide, etc.
  • the positive electrode active material according to a preferred embodiment of the present invention is a secondary particle comprising a large number of primary particles (preferably a single crystal primary particle of a lithium composite oxide having a layered rock salt structure) having an average primary particle size of 0.01 to 5 ⁇ m.
  • primary particles preferably a single crystal primary particle of a lithium composite oxide having a layered rock salt structure
  • Form tertiary particles, and the tertiary particles have a volume-based D50 average particle size of 1 to 100 ⁇ m, a porosity of 1 to 30%, an open pore ratio of 50% or more, and an average open pore size of 0.1 to 5 ⁇ m.
  • a value obtained by dividing the average particle diameter of primary particles by the average open pore diameter is 0.1 to 5.
  • the positive electrode active material having such a configuration a large number of primary particles exist around the pores in the tertiary particles, and the direction of electron conduction and lithium ion diffusion between the adjacent primary particles (particularly the direction of electron conduction). Is well aligned. For this reason, the path
  • the value of “average primary particle diameter / average open pore diameter” is preferably 0.1 or more and 5 or less, more preferably 0.2 or more and 3 or less, and further preferably 0.3 or more and 1 or less, as described above.
  • the lithium ion conductivity and the electron conductivity in the tertiary particles are maximized. That is, when the value of “average primary particle diameter / average open pore diameter” is 0.1 or more, excessive increase in grain boundary resistance due to excessive number of primary particles present around the pores is prevented. Thus, it is possible to prevent the output characteristics and rate characteristics from being deteriorated.
  • the value of “average primary particle diameter / average open pore diameter” is 5 or less, the number of contact points between the primary particles existing around the pores is increased, and electron conduction and lithium ion diffusion paths (especially electrons) Sufficient conduction path) can be secured to prevent degradation of output characteristics.
  • the positive electrode active material particles have a large number of pores, preferably open pores. That is, in the positive electrode active material particles, the porosity is 1% or more and 30% or less, and the average open pore diameter is 0.1 ⁇ m or more and 5 ⁇ m or less. Furthermore, in this positive electrode active material particle, the value obtained by dividing the average particle size of the single crystal primary particles by the average open pore size is 0.1 or more and 5 or less.
  • the positive electrode active material particles of the present embodiment a large number of single crystal primary particles exist around the pores (to the extent that the grain boundary resistance does not become too large), and electron conduction occurs between a plurality of adjacent single crystal primary particles.
  • the direction of lithium ion diffusion is well aligned. Therefore, the path
  • the secondary particles constituting the positive electrode active material particles are derived from the used hydroxide raw material, and the (003) plane where electron conduction and lithium ion diffusion are performed is outside the center of the secondary particles. They are lined up towards. For this reason, the exposure of the lithium ion entrance / exit surface and the electron conduction surface on the inner surface formed by the outer surface and open pores that are in contact with the electrolytic solution is increased, and the electron conduction in the secondary particles and the resistance of lithium ion diffusion are also increased. Can be reduced.
  • the secondary particles are typically substantially spherical, the radial orientation is likely to be aligned in substantially the same direction at the contact point between adjacent secondary particles, and the direction of electron conduction and lithium ion diffusion (especially the direction of electron conduction) is accordingly increased. It is easy to arrange well between secondary particles. From this point of view, it can be said that it is easy to ensure the path of electron conduction and lithium ion diffusion (particularly the path of electron conduction) in the tertiary particles.
  • the average particle size of the single crystal primary particles is preferably 0.01 ⁇ m or more and 5 ⁇ m or less, more preferably 0.01 ⁇ m or more and 3 ⁇ m or less, and further preferably 0.01 ⁇ m or more and 1.5 ⁇ m or less.
  • the crystallinity of the single crystal primary particles is ensured.
  • the average particle size of the single crystal primary particles is less than 0.1 ⁇ m, the crystallinity of the single crystal primary particles may be reduced, and the output characteristics and rate characteristics of the lithium secondary battery may be reduced.
  • the positive electrode active material particles of the present embodiment even if the average particle size of the single crystal primary particles is 0.1 to 0.01 ⁇ m, no significant reduction in output characteristics or rate characteristics is observed.
  • the average particle diameter (volume-based D50 average particle diameter) of the positive electrode active material particles as the tertiary particles is preferably 1 ⁇ m or more and 100 ⁇ m or less, more preferably 2 ⁇ m or more and 70 ⁇ m or less, and further preferably 3 ⁇ m or more and 50 ⁇ m or less. It is particularly preferably 5 ⁇ m to 40 ⁇ m, most preferably 10 to 20 ⁇ m.
  • the filling rate of the positive electrode active material can be increased, and the output characteristics and rate characteristics of the lithium secondary battery are deteriorated and the flatness of the electrode surface is increased. Can be prevented.
  • the distribution of the average particle diameter of the positive electrode active material particles may be sharp, broad, or have a plurality of peaks. For example, when the average particle size distribution of the positive electrode active material particles is not sharp, the packing density of the positive electrode active material in the positive electrode active material layer is increased, or the adhesion between the positive electrode active material layer and the positive electrode current collector is increased. can do. Thereby, charge / discharge characteristics can be further improved.
  • a positive electrode active material having an average particle diameter within the above range (especially from 5 ⁇ m to 40 ⁇ m) can be obtained stably.
  • the porosity (volume ratio of pores) in the positive electrode active material particles is preferably 1% or more and 30% or less. By making the porosity within this range, the effect of improving the charge / discharge characteristics can be obtained without impairing the capacity. In particular, according to the method of the present invention, there is an advantage that a high open pore ratio can be realized even with a low porosity (for example, 10% or less).
  • the open pore ratio in the positive electrode active material particles is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, and most preferably 90%. That's it.
  • the average open pore diameter in the positive electrode active material particles is preferably 0.1 ⁇ m or more and 5 ⁇ m or less, more preferably 0.2 ⁇ m or more and 3 ⁇ m or less. Is 0.4 ⁇ m or more and 3 ⁇ m or less.
  • generation of relatively large pores can be prevented, and a sufficient amount per volume of the positive electrode active material contributing to charge / discharge can be secured.
  • the positive electrode active material preferably has a tap density of 2.5 to 3.1 g / cc, more preferably 2.6 to 3.0 g / cc.
  • a tap density in such a range means that the positive electrode active material has a high density, and thus a positive electrode active material having a high volumetric energy density is brought about.
  • the positive electrode active material preferably has a press density of 3.0 to 3.5 g / cc, more preferably 3.2 to 3.4 g / cc when uniaxially pressed at a pressure of 1.0 kgf / cm 2. It is.
  • a press density in such a range means that a high density is obtained when the electrode is formed, resulting in a positive electrode active material having a high volumetric energy density.
  • This press density is obtained by weighing 1.5 g of the positive electrode active material on a cylindrical die having a diameter of 20 mm, uniaxially pressing with a load of 1.0 kgf / cm 2 , and then (powder weight) / (bulk volume of pressed powder). It can be determined by calculating.
  • an active material precursor powder that is used in the production of a positive electrode active material for a lithium ion battery.
  • This active material precursor powder is a powder comprising the hydroxide raw material powder, the water-soluble lithium compound, and optionally aggregated particles containing the raw material fine particles as described above with respect to the production method. That is, the hydroxide raw material powder is Ni 1-y M y (OH) 2 (where 0 ⁇ y ⁇ 0.5, M is Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga).
  • the raw material fine particles have the same composition as the hydroxide raw material powder and a particle size smaller than that of the hydroxide raw material powder in an amount of 0 to 25% by mass or less based on the total amount of the hydroxide raw material powder and the fine particles. It is an ingredient.
  • the water-soluble lithium compound is interposed between the secondary particles and / or between the secondary particles and the raw material fine particles, and not only functions as a lithium source but also binds the secondary particles of the hydroxide raw material powder to the tertiary particles.
  • the active material precursor powder corresponds to the granulated powder obtained in the “(3) drying / granulation (tertiary granulation) step” in the method for producing a positive electrode active material described above. Therefore, the description regarding the hydroxide raw material powder, the water-soluble lithium compound, and the raw material fine particles described in “Method for producing positive electrode active material for lithium secondary battery” is also incorporated into the active material precursor powder of this embodiment as it is. Shall.
  • the active material precursor powder of this embodiment has a volume-based D50 average particle diameter of 10 to 40 ⁇ m, preferably 10 to 20 ⁇ m, when converted into a positive electrode active material through the introduction of lithium by firing.
  • the method of introducing lithium by firing may be in accordance with general lithium introduction and firing methods. However, for more accurate evaluation, after adding a lithium compound as necessary, a crucible made of high-purity alumina is used. It is preferable to carry out heat treatment in an oxygen atmosphere (0.1 MPa) at a rate of 50 ° C./h and heat treatment at 765 ° C. for 24 hours. What is necessary is just to measure the volume reference
  • the proportion of particles having a particle size of 1.0 ⁇ m or less on a volume basis is 0 to 40%, preferably 10 to 30%.
  • the particle size distribution is such that the proportion of particles having a particle size of 1.0 to 5.0 ⁇ m is 60 to 100%, preferably 70 to 90%.
  • This deagglomeration may be carried out in accordance with a general deagglomeration technique by ultrasonic irradiation in water. However, in order to perform a more accurate evaluation, after putting the active material precursor powder into water, it is 600 W using an ultrasonic homogenizer.
  • the particle size distribution of the sample slurry thus obtained may be measured using a laser diffraction / scattering particle size distribution measuring device.
  • the active material precursor powder is the precursor powder before being subjected to firing, so the average particle size and particle size in the form as they are. Since it is not easy to determine the distribution uniquely, it is based on the idea that a more objective evaluation method is desirable. And the active material precursor powder of this embodiment characterized by the particle size distribution characteristics within the above range can be obtained by simply introducing lithium by firing (after mixing with a lithium compound as desired) without using a pore-forming agent, A positive electrode active material having a desired porosity and a high open pore ratio that provides high battery characteristics can be obtained very simply.
  • the water-soluble lithium compound include lithium hydroxide, lithium nitrate, lithium chloride, lithium oxide, and lithium peroxide. More preferably, the binder effect is high, the reactivity is high, and lithium can be easily introduced. In terms of lithium hydroxide.
  • Aggregated particles preferably contain a water-soluble lithium compound in a molar ratio of Li / (Ni + M) of 0.01 to 0.20, more preferably 0.02 to 0.15, and even more preferably. 0.04 to 0.10. As described above, when the molar ratio is within this range, the capacity increases in battery characteristics.
  • the active material precursor powder preferably has a porosity of 1 to 30% and an open pore ratio of 50% or more when converted into a positive electrode active material through the introduction of lithium by firing.
  • a more preferable porosity is 3 to 20%, and further preferably 5 to 15%.
  • a more preferable open pore ratio is 60% or more, further preferably 70% or more, particularly preferably 80% or more, and most preferably 90% or more.
  • the active material precursor powder preferably has an average open pore size of 0.2 to 3 ⁇ m, more preferably 0.4 to 3 ⁇ m, when converted into a positive electrode active material through the introduction of lithium by firing.
  • the active material precursor powder preferably has a value obtained by dividing the average particle diameter of the primary particles constituting the positive electrode active material by the average open pore diameter of 0.2 to 3, more preferably 0.3 to 1. .
  • the advantages of being within these numerical ranges are as described above for the positive electrode active material.
  • ⁇ D50 particle size The average particle size of the hydroxide raw material powder, granulated powder (active material precursor powder), and positive electrode active material is determined using a laser diffraction / scattering type particle size distribution measuring device (for example, model number “MT3000-II” manufactured by Nikkiso Co., Ltd.). The volume-based D50 average particle diameter (median diameter) measured using water as a dispersion medium was measured.
  • the positive electrode material active material is filled with resin, and polished so that the cross-section polished surface of the positive electrode active material can be observed with a cross section polisher (CP).
  • CP cross section polisher
  • SEM scanning microscope, “JSM-6390LA” manufactured by JEOL Ltd.
  • JSM-6390LA scanning microscope, “JSM-6390LA” manufactured by JEOL Ltd.
  • Get a cross-sectional image This image is subjected to image processing to divide the void portion and the positive electrode material portion in the cross section, and obtain (area of void portion) / (area of void portion + area of positive electrode material). This was performed with respect to ten secondary particles, and the average value thereof was obtained as the porosity (%).
  • the portion of the void portion that is impregnated with the resin is the open pore
  • the portion of the void portion that is not impregnated with the resin is the closed pore (area of the open pore portion) / (open pore) (Area of the portion + area of the closing mechanism portion). This was performed on 10 secondary particles, and the average value thereof was obtained as the open pore ratio.
  • a vacuum impregnation device device name “Sitback” manufactured by Struers
  • FE-SEM field emission scanning electron microscope: manufactured by JEOL Ltd., product name “JSM-7000F”
  • ⁇ Tap density> After tapping a graduated cylinder containing a powder sample of positive electrode active material particles 200 times using a commercially available tap density measuring device, the tap density was determined by calculating (powder weight) / (bulk volume of powder). .
  • a coin cell type battery was produced as follows. Specifically, the obtained tertiary particle powder, acetylene black, and polyvinylidene fluoride (PVDF) are mixed at a mass ratio of 90: 5: 5 and dispersed in N-methyl-2-pyrrolidone. Thus, a positive electrode active material paste was prepared. This paste was applied on an aluminum foil having a thickness of 20 ⁇ m as a positive electrode current collector so as to have a uniform thickness (thickness after drying: 50 ⁇ m), and punched out into a disk shape having a diameter of 14 mm from the dried sheet.
  • PVDF polyvinylidene fluoride
  • a positive electrode plate was produced by pressing the product at a pressure of 2000 kg / cm 2 .
  • a coin cell was manufactured using the positive electrode plate thus manufactured.
  • the electrolytic solution was prepared by dissolving LiPF 6 in an organic solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at an equal volume ratio to a concentration of 1 mol / L.
  • the output characteristic was evaluated by performing a charge / discharge operation as follows. Specifically, constant current charging was performed until the battery voltage reached 4.3 V at a current value of 0.1 C rate. Thereafter, constant voltage charging was performed until the current value decreased to 1/20 under the current condition of maintaining the battery voltage at 4.3V. After resting for 10 minutes, the battery was discharged at a constant current at a current value of 5C until the battery voltage reached 2.5 V, and then rested for 10 minutes. These charging / discharging operations were defined as 1 cycle, and the cycle was repeated for 2 cycles under the condition of 25 ° C. The value of the discharge capacity at the second cycle was adopted as the measurement result.
  • SOC 10% voltage SOC is an abbreviation for “State Of Charge” and means a state of charge
  • Example 1 Comparative example using a pore-forming agent (1) Preparation of hydroxide raw material powder The composition is (Ni 0.844 Co 0.156 ) (OH) 2 and the secondary particles are almost spherical and primary particles. A nickel-cobalt composite hydroxide powder having a secondary particle diameter (D50) shown in Table 1 in which some of the particles are arranged radially outward from the center of the secondary particles was prepared.
  • This nickel-cobalt composite hydroxide powder can be produced according to a known technique. For example, it was produced as follows.
  • a mixed aqueous solution of nickel sulfate and cobalt sulfate having a molar ratio of Ni: Co 84.4: 15.6 in a molar ratio of 1 mol / L to a reaction vessel containing 20 L of pure water at a charging rate of 50 ml / min.
  • Ammonium sulfate having a concentration of 3 mol / L was continuously continuously fed at a feeding rate of 2 ml / min.
  • an aqueous sodium hydroxide solution having a concentration of 10 mol / L was added so that the pH in the reaction vessel was automatically maintained at 12.5.
  • the temperature in the reaction vessel was maintained at 70 ° C., and was always stirred with a stirrer.
  • the produced nickel / cobalt composite hydroxide was taken out by overflowing from the overflow tube, washed with water, dehydrated, and dried.
  • a pore-forming agent (spherical: manufactured by Air Water Co., Ltd., trade name “Bellpearl R100”) was added so that the ratio to the total powder weight after addition was 2%, and a binder (polyvinyl alcohol: product number VP) -18, 1 part of Nippon Vinegar Pover Co., Ltd.), 1 part of dispersant (product name “Marialim KM-0521”, manufactured by NOF Corporation) and antifoaming agent (1-octanol: Wako Pure Chemical Industries, Ltd.) After adding 0.5 part), the mixture was mixed with a ball mill for 24 hours. The mixture was degassed by stirring under reduced pressure, and a slurry was prepared by adjusting the viscosity to 0.5 Pa ⁇ s (measured using an LVT viscometer manufactured by Brookfield).
  • Examples 2 to 7 Examples in which no pore forming agent is used (tertiary granulation) (1) Preparation of hydroxide raw material powder The composition is (Ni 0.844 Co 0.156 ) (OH) 2 by appropriately changing various conditions in accordance with the same method as in Example 1, and the secondary particles Prepared various nickel-cobalt composite hydroxide powders with secondary particle size (D50) shown in Table 1 in which the particles are almost spherical and some of the primary particles are arranged radially outward from the center of the secondary particles. did.
  • the mixture thus obtained was defoamed by stirring under reduced pressure, and the viscosity was adjusted to 0.5 Pa ⁇ s (measured using a Brookfield LVT viscometer) to prepare a slurry. .
  • Each of the positive electrode active materials obtained in Examples 2 to 7 includes tertiary particles composed of a large number of primary particles having an average primary particle diameter of 0.01 to 5 ⁇ m, and the tertiary particles have a volume basis of 10 to 40 ⁇ m.
  • D50 has an average particle diameter of 1-30%, an open pore ratio of 50% or more, and an average open pore diameter of 0.2-3 ⁇ m, and the average primary pore diameter is divided by the average open pore diameter. The value was 0.2 to 3, and the tap density was 2.5 g / cc or more.
  • Examples 8 and 9 Example in which no pore-forming agent was used (addition of lithium compound in tertiary granulation and slurry preparation process) (1) Preparation of hydroxide raw material powder The composition is (Ni 0.844 Co 0.156 ) (OH) 2 by appropriately changing various conditions in accordance with the same method as in Example 1, and the secondary particles Prepared various nickel-cobalt composite hydroxide powders with secondary particle size (D50) shown in Table 1 in which the particles are almost spherical and some of the primary particles are arranged radially outward from the center of the secondary particles. did.
  • the mixture thus obtained was defoamed by stirring under reduced pressure, and the viscosity was adjusted to 0.5 Pa ⁇ s (measured using a Brookfield LVT viscometer) to prepare a slurry. .
  • Each of the positive electrode active materials obtained in Examples 8 and 9 includes tertiary particles composed of a large number of primary particles having an average primary particle diameter of 0.01 to 5 ⁇ m, and the tertiary particles are based on a volume of 10 to 40 ⁇ m.
  • D50 has an average particle diameter of 1-30%, an open pore ratio of 50% or more, and an average open pore diameter of 0.2-3 ⁇ m, and the average primary pore diameter is divided by the average open pore diameter. The value was 0.2 to 3, and the tap density was 2.5 g / cc or more.
  • Examples 10 to 13 Examples in which no pore-forming agent is used (tertiary granulation, addition of lithium compound in the slurry preparation process)
  • Example 8 in “(2) Slurry preparation process”, the mixing amount of LiOH ⁇ H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.) was expressed in terms of a molar ratio of Li / (Ni 0.81 Co 0.15 Al 0.
  • Example 04 becomes 0.01 (Example 10), 0.05 (Example 11), 0.10 (Example 12) or 0.15 (Example 13), and further "(4) Mixing with lithium compound” , Dried granulated powder and LiOH.H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.), Li / (Ni 0.81 Co 0.15 Al 0.04 ) 1.03 (Example 10) ), 0.99 (Example 11), 0.94 (Example 12) or 0.89 (Example 13), except that the positive electrode active material was prepared and evaluated in the same manner as in Example 8. . The results were as shown in Table 1.
  • Each of the positive electrode active materials obtained in Examples 10 to 13 includes tertiary particles composed of a large number of primary particles having an average primary particle diameter of 0.01 to 5 ⁇ m, and the tertiary particles are based on a volume of 10 to 40 ⁇ m.
  • D50 has an average particle diameter of 1-30%, an open pore ratio of 50% or more, and an average open pore diameter of 0.2-3 ⁇ m, and the average primary pore diameter is divided by the average open pore diameter. The value was 0.2 to 3, and the tap density was 2.5 g / cc or more.
  • Example 14 Comparative example using a pore-forming agent (1) Preparation of hydroxide raw material powder The composition is (Ni 0.5 Co 0.2 Mn 0.3 ) (OH) 2 and the secondary particles are almost spherical. In addition, a nickel / cobalt / manganese composite hydroxide powder having a secondary particle diameter (D50) shown in Table 2 in which some of the primary particles are arranged radially outward from the center of the secondary particles was prepared.
  • This nickel-cobalt-manganese composite hydroxide powder can be produced according to a known technique, and for example, produced as follows.
  • ammonium sulfate having a concentration of 3 mol / L was continuously charged simultaneously at a charging rate of 2 ml / min.
  • an aqueous sodium hydroxide solution having a concentration of 10 mol / L was added so that the pH in the reaction vessel was automatically maintained at 12.5.
  • the temperature in the reaction vessel was maintained at 70 ° C., and was always stirred with a stirrer.
  • the produced nickel-cobalt-manganese composite hydroxide was taken out by overflowing from the overflow tube, washed with water, dehydrated and dried.
  • all of a series of steps i.e., a series of steps excluding water washing, dehydration and drying treatment
  • all of a series of steps i.e., a series of steps excluding water washing, dehydration and drying treatment
  • Firing step (lithium introduction step)
  • the above mixed powder is put into a crucible made of high-purity alumina, heated at 50 ° C./h in an air atmosphere, and heat-treated at 850 ° C. for 24 hours, whereby Li ((Ni 0.5 Co 0 .2 Mn 0.3 ) O 2 powder was obtained, and various measurements were performed on the positive electrode active material thus obtained, and the results shown in Table 2 were obtained.
  • Examples 15 to 20 Examples in which no pore forming agent is used (tertiary granulation) (1) Preparation of hydroxide raw material powder The composition is (Ni 0.5 Co 0.2 Mn 0.3 ) (OH) 2 by appropriately changing various conditions in accordance with the same method as in Example 14. Various nickel-cobalt-manganese composites having secondary particle diameters (D50) shown in Table 2 in which the secondary particles are substantially spherical and part of the primary particles are arranged radially outward from the center of the secondary particles. A hydroxide powder was prepared.
  • Examples 21 to 26 Examples in which no pore-forming agent is used (tertiary granulation, addition of lithium compound in the slurry preparation process)
  • the composition is (Ni 0.5 Co 0.2 Mn 0.3 ) (OH) 2 by appropriately changing various conditions in accordance with the same method as in Example 14.
  • D50 secondary particle diameters
  • LiOH.H 2 O powder was mixed at a molar ratio of Li / (H / O) in the slurry preparation step.
  • Ni 0.5 Co 0.2 Mn 0.3 ) 1.04 was mixed so that the dried granulated powder and the lithium compound were not mixed.
  • Each of the positive electrode active materials obtained in Examples 15 to 26 includes tertiary particles composed of a large number of primary particles having an average primary particle diameter of 0.01 to 5 ⁇ m, and the tertiary particles are based on a volume of 10 to 40 ⁇ m.
  • D50 has an average particle diameter of 1-30%, an open pore ratio of 50% or more, and an average open pore diameter of 0.2-3 ⁇ m, and the average primary pore diameter is divided by the average open pore diameter. The value was 0.2 to 3, and the tap density was 2.5 g / cc or more.

Abstract

Disclosed is a method for producing, without using a pore-forming agent, positive electrode active material which has high battery characteristics, and which has a high open-pore ratio at a predetermined porosity. In this method, primary particles of a composition represented by Ni1-yMy(OH)2 (in the formula, 0<y≦0.5, and M is at least one type of metallic element selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) constitute agglomerated secondary particles. At least some of the primary particles are formed so as to be arranged radially, facing outwards from the centre of a secondary particle. A hydroxide raw material powder or an aggregate thereof is prepared, the hydroxide raw material powder is used or the aggregate is crushed and used, a slurry containing hydroxide raw material powder is processed, a spherical granulated powder is produced using the slurry, a lithium compound is mixed with the granulated powder, and a lithium mixed powder is obtained. The lithium mixed powder is calcinated, causing the granulated powder and the lithium compound to react, and thereby the positive electrode active material for a lithium secondary battery comprising open pores is obtained.

Description

リチウム二次電池用正極活物質の製造方法及びそれに用いられる活物質前駆体粉末Method for producing positive electrode active material for lithium secondary battery and active material precursor powder used therefor
　本発明は、層状岩塩構造を有するリチウム二次電池用正極活物質の製造方法及びそれに用いられる活物質前駆体粉末に関する。 The present invention relates to a method for producing a positive electrode active material for a lithium secondary battery having a layered rock salt structure and an active material precursor powder used therefor.
　リチウム二次電池（リチウムイオン二次電池と称されることもある）における正極活物質として、層状岩塩構造を有するリチウム複合酸化物（リチウム遷移金属酸化物）を用いたものが広く知られている（例えば、特許文献１（特開平５－２２６００４号公報）及び特許文献２（特開２００３－１３２８８７号公報）を参照）。 As a positive electrode active material in a lithium secondary battery (sometimes called a lithium ion secondary battery), a material using a lithium composite oxide (lithium transition metal oxide) having a layered rock salt structure is widely known. (See, for example, Patent Document 1 (Japanese Patent Laid-Open No. 5-226004) and Patent Document 2 (Japanese Patent Laid-Open No. 2003-132877)).
　この種の正極活物質においては、その内部でのリチウムイオン（Ｌｉ＋）の拡散が（００３）面の面内方向（すなわち（００３）面と平行な平面内の任意の方向）で行われる一方、（００３）面以外の結晶面（例えば（１０１）面や（１０４）面）でリチウムイオンの出入りが生じることが知られている。 In this type of positive electrode active material, the diffusion of lithium ions (Li + ) therein is performed in the in-plane direction of the (003) plane (that is, any direction in a plane parallel to the (003) plane). It is known that lithium ions enter and exit from crystal planes other than the (003) plane (for example, the (101) plane or the (104) plane).
　そこで、この種の正極活物質において、リチウムイオンの出入りが良好に行われる結晶面（（００３）面以外の面、例えば（１０１）面や（１０４）面）をより多く電解質と接触する表面に露出させることで、リチウム二次電池の電池特性を向上させる試みがなされている（例えば、特許文献３（国際公開第２０１０／０７４３０４号公報）を参照）。 Therefore, in this type of positive electrode active material, the crystal plane (surface other than the (003) plane, for example, the (101) plane or the (104) plane) on which lithium ions can be satisfactorily entered and exited, is brought into contact with the electrolyte. Attempts have been made to improve the battery characteristics of lithium secondary batteries by exposing them (see, for example, Patent Document 3 (International Publication No. 2010/074304)).
　また、この種の正極活物質において、内部に気孔（空孔あるいは空隙とも称される）を形成したものが知られている（例えば、特許文献４（特開２００２－７５３６５号公報）、特許文献５（特開２００４－０８３３８８号公報）及び特許文献６（特開２００９－１１７２４１号公報）を参照）。 Also, this type of positive electrode active material is known in which pores (also referred to as pores or voids) are formed therein (for example, Patent Document 4 (Japanese Patent Laid-Open No. 2002-75365)). 5 (Japanese Patent Laid-Open No. 2004-083388) and Patent Document 6 (Japanese Patent Laid-Open No. 2009-117241).
特開平５－２２６００４号公報JP-A-5-226004 特開２００３－１３２８８７号公報JP 2003-132877 A 国際公開第２０１０／０７４３０４号公報International Publication No. 2010/074304 特開２００２－７５３６５号公報JP 2002-75365 A 特開２００４－０８３３８８号公報JP 2004-083388 A 特開２００９－１１７２４１号公報JP 2009-117241 A
　所望の空隙率及び平均気孔径を実現するための手法の一つとして、原料に対して、添加剤としての造孔剤（空隙形成材）を配合することが考えられる。このような造孔剤の例としては、仮焼成工程において分解（主に蒸発あるいは炭化）される、有機合成樹脂からなる粒子状又は繊維状物質が考えられる。しかしながら、本発明者らの知見によれば、体積エネルギー密度を上げるために造孔剤を減量して空隙量を減らすと、空隙が連通しにくく、閉気孔化してしまい、電解液や導電助材が気孔内に進入できなくなることで出力特性が落ちることがある。したがって、このような造孔剤を使用することなく所望の空隙率及び平均気孔径を実現することができれば好都合である。 As one method for realizing a desired porosity and average pore diameter, it is conceivable to add a pore-forming agent (void forming material) as an additive to the raw material. As an example of such a pore-forming agent, a particulate or fibrous substance made of an organic synthetic resin, which is decomposed (mainly evaporated or carbonized) in a temporary firing step, can be considered. However, according to the knowledge of the present inventors, when the pore-forming agent is reduced in order to increase the volume energy density and the amount of voids is reduced, the voids are difficult to communicate with each other, and closed pores are formed. May not be able to enter the pores, which may reduce the output characteristics. Therefore, it is advantageous if a desired porosity and average pore diameter can be realized without using such a pore-forming agent.
　本発明者らは、今般、略球状の二次粒子原料粉末を、空隙を含むよう造粒・球状化する（以下「三次粒化」と表記することがある）ことで、造孔剤を使用することなく、高い電池特性をもたらす、所望の空隙率で開気孔比率の高い正極活物質を製造できるとの知見を得た。 The present inventors now use a pore-forming agent by granulating and spheroidizing a substantially spherical secondary particle raw material powder to include voids (hereinafter sometimes referred to as “tertiary granulation”). Thus, it was found that a positive electrode active material having a desired porosity and a high open pore ratio can be produced, which provides high battery characteristics.
　したがって、本発明の目的は、造孔剤を使用することなく、高い電池特性をもたらす、所望の空隙率で開気孔比率の高い正極活物質を製造することにある。 Therefore, an object of the present invention is to produce a positive electrode active material having a desired porosity and a high open pore ratio, which provides high battery characteristics without using a pore-forming agent.
　本発明の一態様によれば、リチウムイオン電池用正極活物質の製造方法であって、
　Ｎｉ１－ｙＭｙ（ＯＨ）２（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表される組成の一次粒子が多数凝集した二次粒子からなり、前記一次粒子の少なくとも一部が前記二次粒子の中心から外方に向かって放射状に並んでなる、水酸化物原料粉末又はその凝集物を用意する工程と、
　前記水酸化物原料粉末を用いて又は前記凝集物を解砕して用いて、前記水酸化物原料粉末を含むスラリーを調製する工程と、
　前記スラリーを用いて略球状の造粒粉末を作製する工程と、
　前記造粒粉末にリチウム化合物を混合してリチウム混合粉末を得る工程と、
　前記リチウム混合粉末を焼成して前記造粒粉末とリチウム化合物を反応させ、それにより開気孔を備えたリチウム二次電池用正極活物質を得る工程と、
を含んでなる方法が提供される。 According to one aspect of the present invention, there is provided a method for producing a positive electrode active material for a lithium ion battery,
Ni 1-y M y (OH) 2 (where 0 <y ≦ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles. Preparing a hydroxide raw material powder or an aggregate thereof;
Using the hydroxide raw material powder or pulverizing the aggregate to prepare a slurry containing the hydroxide raw material powder; and
Producing a substantially spherical granulated powder using the slurry;
Mixing the lithium compound with the granulated powder to obtain a lithium mixed powder;
Firing the lithium mixed powder to react the granulated powder with a lithium compound, thereby obtaining a positive active material for a lithium secondary battery having open pores;
A method comprising is provided.
　本発明の別の一態様によれば、リチウムイオン電池用正極活物質の製造方法であって、
　Ｎｉ１－ｙＭｙ（ＯＨ）２（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表される組成の一次粒子が多数凝集した二次粒子からなり、前記一次粒子の少なくとも一部が前記二次粒子の中心から外方に向かって放射状に並んでなる、水酸化物原料粉末又はその凝集物を用意する工程と、
　前記水酸化物原料粉末を用いて又は前記凝集物を解砕して用いて、前記水酸化物原料粉末及び水酸化リチウムを含むスラリーを調製する工程と、
　前記スラリーを用いて略球状の造粒粉末を作製する工程と、
　前記造粒粉末を焼成して前記造粒粉末と前記水酸化リチウムを反応させ、それにより開気孔を備えたリチウム二次電池用正極活物質を得る工程と、
を含んでなる方法が提供される。 According to another aspect of the present invention, a method for producing a positive electrode active material for a lithium ion battery, comprising:
Ni 1-y M y (OH) 2 (where 0 <y ≦ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles. Preparing a hydroxide raw material powder or an aggregate thereof;
Using the hydroxide raw material powder or pulverizing the aggregate to prepare a slurry containing the hydroxide raw material powder and lithium hydroxide;
Producing a substantially spherical granulated powder using the slurry;
Calcining the granulated powder to react the granulated powder with the lithium hydroxide, thereby obtaining a positive electrode active material for a lithium secondary battery having open pores;
A method comprising is provided.
　本発明の更に別の一態様によれば、リチウムイオン電池用正極活物質の製造に用いられる活物質前駆体粉末であって、
　Ｎｉ１－ｙＭｙ（ＯＨ）２（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表される組成の一次粒子が多数凝集した二次粒子からなり、前記一次粒子の少なくとも一部が前記二次粒子の中心から外方に向かって放射状に並んでなる、水酸化物原料粉末と、
　前記水酸化物原料粉末及び原料微粒子の合計量に対して０～２５質量％以下の量の、前記水酸化物原料粉末と同様の組成及び前記水酸化物原料粉末よりも小さい粒径を有する原料微粒子と、
　前記二次粒子間及び／又は前記二次粒子及び前記原料微粒子間に介在する水溶性リチウム化合物と、
を含んでなる凝集粒子からなり、前記活物質前駆体粉末が、水中で超音波照射により解凝集された場合に、体積基準で、粒径１．０μｍ以下の粒子の割合が０～４０％であり、粒径１．０～５．０μｍの粒子の割合が６０～１００％である粒度分布を有し、かつ、焼成によるリチウム導入を経て正極活物質とされた場合に、１０～４０μｍの体積基準Ｄ５０平均粒径を有する、活物質前駆体粉末が提供される。 According to still another aspect of the present invention, there is provided an active material precursor powder used for manufacturing a positive electrode active material for a lithium ion battery,
Ni 1-y M y (OH) 2 (where 0 <y ≦ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles. Hydroxide raw material powder,
A raw material having the same composition as the hydroxide raw material powder and a particle size smaller than that of the hydroxide raw material powder, in an amount of 0 to 25% by mass or less based on the total amount of the hydroxide raw material powder and the raw material fine particles Fine particles,
A water-soluble lithium compound interposed between the secondary particles and / or between the secondary particles and the raw material fine particles;
When the active material precursor powder is deagglomerated in water by ultrasonic irradiation, the proportion of particles having a particle size of 1.0 μm or less is 0 to 40% on a volume basis. And having a particle size distribution in which the proportion of particles having a particle size of 1.0 to 5.0 μm is 60 to 100%, and a volume of 10 to 40 μm when made into a positive electrode active material through the introduction of lithium by firing. An active material precursor powder having a reference D50 average particle size is provided.
本発明の方法における開気孔の形成を説明するための模式図である。It is a schematic diagram for demonstrating formation of the open pore in the method of this invention. 例２において本発明の範囲内の条件で製造された正極活物質のＳＥＭ画像である。4 is a SEM image of a positive electrode active material produced in Example 2 under conditions within the scope of the present invention.
　定義
　本明細書で使用される幾つかの用語についての定義を以下に示す。 Definitions Listed below are definitions for some terms used in this specification.
　「一次粒子」とは、内部に結晶粒界を含まない単位粒子をいう。これに対し、一次粒子が凝集したものや、単結晶一次粒子が複数（多数）集合したものを、「二次粒子」という。なお、本明細書中に「三次粒子」なる用語が使用されることがあるが、これは二次粒子が多数凝集された造粒粉末の粒子を表現するための便宜上の用語であり、あくまで定義上は「二次粒子」の範疇に含まれる。「平均粒子径」は、粒子の直径の平均値である。かかる「直径」は、典型的には、当該粒子を同体積あるいは同断面積を有する球形と仮定した場合の、当該球形における直径である。なお、「平均値」は、個数基準で算出されたものが適している。一次粒子の平均粒子径は、例えば、二次粒子の表面あるいは断面を走査電子顕微鏡（ＳＥＭ）で観察することで求めることが可能である。二次粒子の平均粒子径は、レーザ回折／散乱式粒度分布測定装置（例えば、日機装株式会社製、型番「ＭＴ３０００－ＩＩ」）を用いて、水を分散媒として測定される体積基準Ｄ５０平均粒子径（メディアン径）によって評価される。 “Primary particles” refers to unit particles that do not contain crystal grain boundaries inside. On the other hand, those in which primary particles are aggregated and those in which a plurality (large number) of single-crystal primary particles are aggregated are referred to as “secondary particles”. The term “tertiary particles” is sometimes used in the present specification, but this is a term used for convenience to express particles of agglomerated powder in which a large number of secondary particles are aggregated. The above is included in the category of “secondary particles”. The “average particle diameter” is an average value of particle diameters. The “diameter” is typically a diameter of the sphere when the particle is assumed to be a sphere having the same volume or the same cross-sectional area. The “average value” is preferably calculated on the basis of the number. The average particle diameter of the primary particles can be determined, for example, by observing the surface or cross section of the secondary particles with a scanning electron microscope (SEM). The average particle size of the secondary particles is a volume-based D50 average particle measured using water as a dispersion medium using a laser diffraction / scattering particle size distribution analyzer (for example, model number “MT3000-II” manufactured by Nikkiso Co., Ltd.). It is evaluated by the diameter (median diameter).
　「空隙率（ｖｏｉｄａｇｅ）」は、本発明の正極活物質における、空隙（気孔：開気孔及び閉気孔を含む）の体積比率である。「空隙率」は、「気孔率（ｐｏｒｏｓｉｔｙ）」と称されることもある。この「空隙率」は、例えば、嵩密度と真密度とから計算上求められる。「開気孔」は、気孔のうち、外部と連通している気孔である。「閉気孔」は、気孔のうち、外部と連通していない気孔である。 “Voidage” is the volume ratio of voids (including pores: including open pores and closed pores) in the positive electrode active material of the present invention. “Porosity” is sometimes referred to as “porosity”. This “porosity” is calculated from, for example, the bulk density and the true density. “Open pores” are pores communicating with the outside among the pores. “Closed pores” are pores which are not communicated with the outside among the pores.
　「開気孔比率」は、二次粒子中の全気孔に占める外気と連通する開気孔の比率である。即ち、開気孔比率は、（開気孔部分の面積）／（開気孔部分の面積＋閉気孔部分の面積）である。開気孔は外部と連通しているので外部から樹脂を注入することができ、閉気孔は外部と連通していないので外部から樹脂を注入することができない。そこで、開気孔比率は、真空含浸装置を用いて開気孔中に存在する空気を十分に排除しながら空隙内（従って、開気孔内）に樹脂を注入する樹脂埋めを行い、空隙のうち樹脂が含浸されている部分を開気孔として扱い、空隙のうち樹脂が含浸されていない部分を閉気孔として扱い、これらの面積を、例えば、前記二次粒子の断面のＳＥＭ写真の画像処理から求め、次いで、（開気孔部分の面積）／（開気孔部分の面積＋閉気孔部分の面積）を算出することによって求めることができる。 “Open pore ratio” is the ratio of open pores communicating with outside air in all pores in the secondary particles. That is, the open pore ratio is (area of open pore portion) / (area of open pore portion + area of closed pore portion). Since the open pores communicate with the outside, the resin can be injected from the outside, and the closed pores do not communicate with the outside, so the resin cannot be injected from the outside. Therefore, the open pore ratio is determined by performing resin filling in which a resin is injected into the gap (and thus in the open pore) while sufficiently removing the air present in the open pore using a vacuum impregnation device. The impregnated portion is treated as an open pore, the portion of the void not impregnated with resin is treated as a closed pore, and these areas are obtained from, for example, image processing of a SEM photograph of the cross-section of the secondary particle, , (Area of open pore portion) / (area of open pore portion + area of closed pore portion).
　「平均開気孔径」は、開気孔の平均気孔径を意味し、二次粒子内の開気孔の、直径の平均値である。この「直径」は、典型的には、開気孔を同体積あるいは同断面積を有する球形と仮定した場合の、当該球形における直径である。なお、「平均値」は、体積基準で算出したされたものが適している。また、平均開気孔径は、例えば、二次粒子の断面のＳＥＭ写真の画像処理や、水銀圧入法等の、周知の方法によって求めることが可能である。 “Average open pore diameter” means the average pore diameter of the open pores, and is the average value of the diameters of the open pores in the secondary particles. This “diameter” is typically the diameter of the spherical shape when the open pores are assumed to be spherical with the same volume or the same cross-sectional area. The “average value” is preferably calculated on a volume basis. Further, the average open pore diameter can be determined by a known method such as image processing of an SEM photograph of the cross section of the secondary particle or mercury intrusion method.
　「タップ密度」は、粉体試料を入れた容器を機械的にタップした後に得られる、増大した嵩密度である。タップ密度は粉体試料を入れた測定用メスシリンダー又は容器を機械的にタップすることにより得られる。タップ密度の測定は、粉体の初期体積又は質量を測定した後、測定用メスシリンダー又は容器を機械的にタップし、体積又は質量変化が殆ど認められなくなるまで体積又は質量を読み取ることにより行われる。 “Tap density” is an increased bulk density obtained after mechanically tapping a container containing a powder sample. The tap density is obtained by mechanically tapping a measuring graduated cylinder or container containing a powder sample. The tap density is measured by measuring the initial volume or mass of the powder and then mechanically tapping the measuring graduated cylinder or container and reading the volume or mass until almost no change in volume or mass is observed. .
　「プレス密度」は、粉体試料を金型等において一定のプレス圧で錠剤成形した際に得られる嵩密度である。 “Press density” is a bulk density obtained when a powder sample is formed into a tablet with a constant press pressure in a mold or the like.
　リチウム二次電池用正極活物質の製造方法
　本発明は、層状岩塩構造を有するリチウム二次電池用正極活物質の製造方法に関するものである。「層状岩塩構造」とは、リチウム層とリチウム以外の遷移金属層とが酸素の層を挟んで交互に積層された結晶構造（典型的にはα－ＮａＦｅＯ２型構造：立方晶岩塩型構造の［１１１］軸方向に遷移金属とリチウムとが規則配列した構造）をいう。本発明の方法は、一次粒子が多数凝集した略球状の二次粒子からなり、一次粒子の少なくとも一部が二次粒子の中心から外方に向かって並んでなる水酸化物原料粉末を作製し、水酸化物原料粉末を含むスラリーを用いて、空隙を含む略球状の造粒粉末を作製し、これをリチウム化合物と混合したのち焼成に付して造粒粉末をリチウム化合物と反応させることを含んでなる。このように本発明の方法にあっては、原料粉末の略球状の二次粒子原料を、空隙を含むよう造粒・球状化（三次粒化）することで、造孔剤を使用することなく、高い電池特性をもたらす、所望の空隙率で開気孔比率の高い正極活物質を製造することができる。 TECHNICAL FIELD The present invention of the positive electrode active material for a lithium secondary battery, a method for producing a cathode active material for a lithium secondary battery having a layered rock salt structure. “Layered rock salt structure” means a crystal structure in which lithium layers and transition metal layers other than lithium are alternately stacked with oxygen layers in between (typically α-NaFeO 2 type structure: cubic rock salt type structure) [111] A structure in which transition metals and lithium are regularly arranged in the axial direction. The method of the present invention produces a hydroxide raw material powder comprising substantially spherical secondary particles in which a large number of primary particles are aggregated, wherein at least a part of the primary particles are arranged outward from the center of the secondary particles. The slurry containing the hydroxide raw material powder is used to produce a substantially spherical granulated powder containing voids, which is mixed with a lithium compound and then subjected to firing to cause the granulated powder to react with the lithium compound. Comprising. Thus, in the method of the present invention, the substantially spherical secondary particle raw material of the raw material powder is granulated and spheroidized (tertiary granulated) so as to include voids, without using a pore forming agent. Thus, a positive electrode active material having a desired porosity and a high open pore ratio can be produced, which provides high battery characteristics.
　すなわち、本発明の方法においては、まず、ｐＨおよび温度を調整した槽内に、金属元素水溶液、苛性アルカリ水溶液、およびアンモニウムイオン供給体を、その濃度や流量を制御しながら連続的に供給することで、一次粒子が多数凝集した略球状の二次粒子からなり、一次粒子の少なくとも一部が二次粒子の中心から外方に向かって並んでなる水酸化物原料粉末を作製する。次いで、図１に模式的に示されるように、原料二次粒子を含むスラリーを調製し、これをスプレー乾燥等で乾燥させることで、略球状の造粒粉末を得る。こうして得られた造粒粉末は原料二次粒子が多数凝集してなる点でいわば三次粒粉末と表現することもできるものである。このような造粒粉末には、原料粉末の略球状に起因して、造粒粉末を構成する原料二次粒子粉末の粒子間に多数の隙間が形成されることになる。そして、このような造粒粉末を焼成すると、多数の隙間が、焼成体としての正極活物質の外部と細かく連通しやすい多数の空隙をもたらし、空隙量を減らした際も開気孔化しやすくなる。前述のとおり、造孔剤を内在させることにより焼成又は仮焼時に造孔剤の溶融又は気化を利用して空隙を形成する手法も考えられるが、その場合には、体積エネルギー密度を上げるべく造孔剤の減量により空隙量を減らすと、空隙が連通しにくく、閉気孔化してしまい、電解液や導電助材が気孔内に進入できなくなることで出力特性が落ちるという問題があった。また、焼成温度等の調整によっても孔は形成できるものの、空隙量が少ない領域では閉気孔化してしまうという問題もあった。閉気孔化しないまでも、開気孔が貫通孔でない（表面への出入り口が１つしかない）状態となってしまい、電解液の注液時、気孔内のガスが抜けにくくなることで、電解液が浸透しにくくなる問題もあった。開気孔を貫通孔としたい場合は、焼成時の緻密化を抑え、１次粒子間に細かい気孔（たとえば０．１μｍ以下）を形成することで、造孔剤由来の空隙を、３次元的に連結する方法が考えられるが、体積エネルギー密度が下がる問題や、粒界抵抗が上がり、電子伝導、及びリチウムイオン拡散の抵抗も増大するという問題もあった。このような問題が本発明の方法によれば効果的に解消ないし低減される。 That is, in the method of the present invention, first, an aqueous metal element solution, an aqueous caustic solution, and an ammonium ion supplier are continuously supplied into a tank adjusted in pH and temperature while controlling the concentration and flow rate. Thus, a hydroxide raw material powder composed of substantially spherical secondary particles in which a large number of primary particles are aggregated and in which at least a part of the primary particles are arranged outward from the center of the secondary particles is produced. Next, as schematically shown in FIG. 1, a slurry containing raw material secondary particles is prepared and dried by spray drying or the like to obtain a substantially spherical granulated powder. The granulated powder thus obtained can be expressed as a tertiary particle powder in that many secondary particles are aggregated. In such a granulated powder, a large number of gaps are formed between the particles of the raw material secondary particle powder constituting the granulated powder due to the substantially spherical shape of the raw material powder. When such a granulated powder is fired, a large number of gaps provide a large number of voids that are easily communicated with the outside of the positive electrode active material as a fired body, and open pores are easily formed even when the amount of voids is reduced. As described above, a method of forming voids by utilizing melting or vaporization of the pore-forming agent during firing or calcination by incorporating a pore-forming agent is also conceivable, but in that case, it is necessary to increase the volume energy density. If the amount of voids is reduced by reducing the amount of the pore agent, there is a problem in that the voids are difficult to communicate with each other and closed pores are formed, so that the output characteristics are deteriorated because the electrolyte and the conductive additive cannot enter the pores. Further, although pores can be formed by adjusting the firing temperature or the like, there is a problem that closed pores are formed in a region where the amount of voids is small. Even if the pores are not closed, the open pores are not through-holes (there is only one entrance / exit to the surface), and it is difficult for the gas in the pores to escape when the electrolyte is injected. There was also a problem that it was difficult to penetrate. When the open pores are desired to be through-holes, the pores derived from the pore-forming agent are three-dimensionally formed by suppressing densification during firing and forming fine pores (for example, 0.1 μm or less) between the primary particles. Although a method of connection is conceivable, there is a problem that the volume energy density is lowered and a problem that the grain boundary resistance is increased and the resistance of electron conduction and lithium ion diffusion is also increased. Such a problem is effectively eliminated or reduced by the method of the present invention.
　以下、本発明の方法における各工程について具体的に説明する。 Hereinafter, each step in the method of the present invention will be specifically described.
（１）水酸化物原料粉末の作製
　本発明の方法においては、Ｎｉ１－ｙＭｙ（ＯＨ）２（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表される組成の一次粒子が多数凝集した二次粒子からなり、一次粒子の少なくとも一部が二次粒子の中心から外方に向かって放射状に並んでなる、水酸化物原料粉末又はその凝集物を用意する。好ましくは、０．１５≦ｙ≦０．４であり、好ましい金属元素ＭはＣｏ、Ａｌ、Ｍｇ及びＭｎからなる群から選択される少なくとも１種又は２種の金属元素であり、より好ましくはＡｌ、Ｍｇ及びＭｎからなる群から選択される少なくとも１種とＣｏとを含み、特に好ましい金属元素Ｍの組合せはＣｏ及びＡｌ、又はＣｏ及びＭｎである。 (1) Preparation of hydroxide raw material powder In the method of the present invention, Ni 1-y M y (OH) 2 (where 0 <y ≦ 0.5, M is Co, Al, Mg, Mn, Ti , Fe, Cr, Zn, and Ga, at least one metal element selected from the group consisting of secondary particles in which a large number of primary particles are aggregated, and at least part of the primary particles are secondary. A hydroxide raw material powder or an aggregate thereof is prepared, which is arranged radially outward from the center of the particle. Preferably, 0.15 ≦ y ≦ 0.4, and the preferred metal element M is at least one or two metal elements selected from the group consisting of Co, Al, Mg and Mn, more preferably Al. , Mg and Mn and at least one selected from the group consisting of Co and Co, and particularly preferred combinations of metal elements M are Co and Al, or Co and Mn.
　もっとも、これらの金属元素Ｍのうち、Ａｌ等の所定の元素を水酸化物原料粉末には含めないか又は不足させておき、後続の任意の工程で添加してもよい。この場合、Ｃｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種であって、水酸化物原料粉末に含まれないか又は水酸化物原料粉末において不足する元素を含む化合物（例えば酸化物、水酸化物及びその水和物等）を、後続のスラリー化工程及び／又はリチウム混合工程でスラリー及び／又は造粒粉末に添加するのが好ましい。この点、スラリー化工程の方が添加元素化合物を混合しやすい点でより好ましい。このように、最終的に所望の組成の正極活物質が得られるかぎり、金属元素Ｍの一部の元素はどの段階で添加されてもよい。特に、後続の任意の工程で添加される金属元素Ｍの一部は、主要添加元素（例えばＣｏ又はＭｎ）ではなく、微量添加元素（例えばＣｏ及びＭｎ以外の元素）であるのが好ましい。これは、複合水酸化物である水酸化物原料粉末を作製する際、元素の種類が少ない方が粒子形状や組成の制御が容易になるためである。すなわち、水酸化物原料粉末の作製時においては金属元素Ｍの種類を主要添加元素（例えばＣｏ又はＭｎ）のみに減らして粒子形状や組成の制御を容易にする一方、水酸化物原料粉末を作製する溶液プロセスでは組成の制御が難しい微量添加元素（例えばＣｏ及びＭｎ以外の元素）を後続の任意の工程で添加して、所望の正極活物質組成をより正確に得ることができる。 However, among these metal elements M, a predetermined element such as Al may not be included or made insufficient in the hydroxide raw material powder, and may be added in any subsequent step. In this case, it is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga and is not included in the hydroxide raw material powder or hydroxide raw material powder It is preferable to add a compound (for example, an oxide, a hydroxide and a hydrate thereof) containing an element deficient in the slurry and / or the granulated powder in a subsequent slurrying step and / or a lithium mixing step. In this respect, the slurrying step is more preferable because the additive element compound can be easily mixed. Thus, as long as a positive electrode active material having a desired composition is finally obtained, a part of the metal element M may be added at any stage. In particular, it is preferable that a part of the metal element M added in any subsequent step is not a main additive element (for example, Co or Mn) but a small amount of additive element (for example, an element other than Co and Mn). This is because, when producing a hydroxide raw material powder that is a composite hydroxide, control of the particle shape and composition becomes easier when the number of types of elements is smaller. That is, at the time of preparing the hydroxide raw material powder, the type of the metal element M is reduced to only the main additive element (for example, Co or Mn) to facilitate the control of the particle shape and composition, while the hydroxide raw material powder is prepared. By adding a trace amount of an additive element (for example, an element other than Co and Mn) that is difficult to control in the solution process, a desired positive electrode active material composition can be obtained more accurately.
　水酸化物原料粉末は、１．４０ｇ／ｃｃ以上のタップ密度を有するのが好ましく、より好ましくは１．５ｇ／ｃｃ以上であり、更に好ましくは１．６ｇ／ｃｃ以上である。タップ密度が高いほど後述する三次粒粉末中の空隙部と粒子部の粗密差が大きくなるため、少ない空隙率でも高い開気孔比率を実現することが可能となるが、１．９ｇ／ｃｃ以下であるのが現実的である。また、水酸化物原料粉末は、二次粒径として、１～５μｍの体積基準Ｄ５０平均粒径を有するのが好ましく、より好ましくは２～４μｍであり、更に好ましくは２～３μｍである。この程度の粒径であると三次粒粉末中に適切な大きさの隙間が多数形成され、少ない空隙率でも高い開気孔比率を達成するのに有利となる。上記範囲の二次粒径を有する粉末として、一次粒子が多数凝集した５μｍ以上の体積基準Ｄ５０平均粒径を有する二次粒子からなり、一次粒子の少なくとも一部が二次粒子の中心から外方に向かって放射状に並んでなる水酸化物原料粉末を軽く粉砕したものを用いてもよい。あるいは、上述した放射状配向を有する水酸化物原料粉末の凝集物を用いてもよく、そのような凝集物は５～３０μｍの体積基準Ｄ５０平均粒径を有するのが好ましく、より好ましくは１０～２０μｍである。 The hydroxide raw material powder preferably has a tap density of 1.40 g / cc or more, more preferably 1.5 g / cc or more, and still more preferably 1.6 g / cc or more. The higher the tap density, the larger the difference in density between the voids and the particles in the tertiary particle powder described later, so that a high open pore ratio can be achieved even with a small porosity, but at 1.9 g / cc or less. It is realistic. The hydroxide raw material powder preferably has a volume-based D50 average particle size of 1 to 5 μm as a secondary particle size, more preferably 2 to 4 μm, and still more preferably 2 to 3 μm. When the particle size is about this level, a large number of gaps of an appropriate size are formed in the tertiary powder, which is advantageous for achieving a high open pore ratio even with a small porosity. The powder having a secondary particle size in the above range is composed of secondary particles having a volume-based D50 average particle size of 5 μm or more in which many primary particles are aggregated, and at least a part of the primary particles is outward from the center of the secondary particles It is also possible to use a lightly pulverized hydroxide raw material powder arranged radially toward the surface. Alternatively, agglomerates of hydroxide raw material powder having the radial orientation described above may be used, and such agglomerates preferably have a volume-based D50 average particle size of 5 to 30 μm, more preferably 10 to 20 μm. It is.
　このような水酸化物原料粉末は公知の技術に従って作製することができる（例えば特許文献３及び４を参照）。例えば、ｐＨ及び温度を調整した槽内に、ニッケル塩水溶液、金属元素Ｍ含有水溶液、苛性アルカリ水溶液、及びアンモニウムイオン供給体を、その濃度及び流量を制御しながら連続的に供給して採取する方法が挙げられる。この時、上記タップ密度やＤ５０平均粒径を満たすためには、槽内のｐＨを１０．０～１２．０とし、温度を４０～７０℃とするのが好ましい。 Such a hydroxide raw material powder can be produced according to a known technique (see, for example, Patent Documents 3 and 4). For example, a method in which a nickel salt aqueous solution, a metal element M-containing aqueous solution, a caustic alkaline aqueous solution, and an ammonium ion supplier are continuously supplied and controlled while controlling the concentration and flow rate in a tank adjusted in pH and temperature. Is mentioned. At this time, in order to satisfy the tap density and the D50 average particle diameter, it is preferable that the pH in the tank is 10.0 to 12.0 and the temperature is 40 to 70 ° C.
（２）スラリー化工程
　上記水酸化物原料粉末又は凝集物を用いてスラリーを形成する。このスラリーの調製は、たとえば水酸化物原料粉末（略球状の二次粒子）を水等の分散媒と混合することによって行うことができるが、上述した放射状配向を有する水酸化物原料粉末の凝集物を用いる場合には凝集物を解砕して、望ましくは上述した放射状配向を有する水酸化物原料粉末の形態にした上でスラリー調製に用いるのが好ましい。さらに、空隙率や空隙径を制御する目的で、原料粉末よりも小径の原料微粒子を原料粉末に混合してもよい。原料微粒子は水酸化物原料粉末と同様の組成を有するのが好ましく、水酸化物原料粉末を解砕することにより得られたものであってもよいし、水酸化物原料粉末とは別に作製されたものであってもよい。また、原料微粒子は水酸化物原料粉末と同様の放射状の配向を有していてもよいが、配向を有していなくてもよい。原料微粒子はスラリー中における原料粉末と原料微粒子の粒径比や配合割合を制御することによって、空隙率及び空隙径を適宜変化させることができる。また、原料微粒子の凝集力が高いことから、造粒粉末を壊れにくくすることもできる。原料微粒子の体積基準Ｄ５０平均粒径は１０ｎｍ～７００ｎｍが好ましく、５０ｎｍ～５００ｎｍがより好ましい。また、原料粉末及び原料微粒子の合計量に対する原料微粒子の比率は２５質量％以下であるのが好ましく、より好ましくは２０質量％以下である。また、バインダーや分散剤を加えてもよいし、加えなくてもよい。 (2) Slurry process A slurry is formed using the said hydroxide raw material powder or aggregate. This slurry can be prepared, for example, by mixing a hydroxide raw material powder (substantially spherical secondary particles) with a dispersion medium such as water, and agglomeration of the hydroxide raw material powder having the radial orientation described above. In the case of using a product, it is preferable to use the product in the slurry preparation after crushing the agglomerate and desirably forming the above-mentioned hydroxide raw material powder having the radial orientation. Furthermore, for the purpose of controlling the porosity and the void diameter, raw material fine particles having a diameter smaller than that of the raw material powder may be mixed with the raw material powder. The raw material fine particles preferably have the same composition as the hydroxide raw material powder, and may be obtained by pulverizing the hydroxide raw material powder, or prepared separately from the hydroxide raw material powder. It may be. The raw material fine particles may have a radial orientation similar to that of the hydroxide raw material powder, but may not have an orientation. For the raw material fine particles, the porosity and the void diameter can be appropriately changed by controlling the particle size ratio and the mixing ratio of the raw material powder and the raw material fine particles in the slurry. In addition, since the raw material fine particles have high cohesion, the granulated powder can be made difficult to break. The volume-based D50 average particle diameter of the raw material fine particles is preferably 10 nm to 700 nm, and more preferably 50 nm to 500 nm. The ratio of the raw material fine particles to the total amount of the raw material powder and the raw material fine particles is preferably 25% by mass or less, more preferably 20% by mass or less. In addition, a binder or a dispersant may or may not be added.
　好ましいスラリーは、水を分散媒として含む水系スラリーである。この場合、水系スラリーに水溶性リチウム化合物を更に含ませてリチウム化合物水溶液とするのがより好ましい。水溶性リチウム化合物はリチウム源として機能するのみならず、後続の造粒工程において、水酸化物原料粉末の二次粒子同士を結着させて三次粒子とするためのバインダーとしても機能しうる。したがって、水溶性リチウム化合物の水系スラリー中での使用により、所望の粒径の造粒粉末を安定的に得やすくするとともに、必要に応じて後続のリチウム混合工程を不要にすることすら可能になる。その上、有機バインダーの使用も不要にすることができるので、有機バインダーを消失させるための脱脂工程を無くすこともできる。水溶性リチウム化合物の好ましい例としては、水酸化リチウム、硝酸リチウム、塩化リチウム、酸化リチウム、及び過酸化リチウムが挙げられ、より好ましくは、バインダー効果が高く、かつ、反応性が高くリチウム導入しやすい点で水酸化リチウムである。 A preferred slurry is an aqueous slurry containing water as a dispersion medium. In this case, it is more preferable to further include a water-soluble lithium compound in the aqueous slurry to form an aqueous lithium compound solution. The water-soluble lithium compound not only functions as a lithium source, but can also function as a binder for binding secondary particles of the hydroxide raw material powder to form tertiary particles in the subsequent granulation step. Therefore, the use of a water-soluble lithium compound in an aqueous slurry makes it easy to stably obtain a granulated powder having a desired particle size, and it is possible to eliminate the need for a subsequent lithium mixing step if necessary. . In addition, since the use of an organic binder can be eliminated, a degreasing process for eliminating the organic binder can be eliminated. Preferable examples of the water-soluble lithium compound include lithium hydroxide, lithium nitrate, lithium chloride, lithium oxide, and lithium peroxide. More preferably, the binder effect is high, the reactivity is high, and lithium can be easily introduced. In terms of lithium hydroxide.
　水系スラリーは、水溶性リチウム化合物を、Ｌｉ／（Ｎｉ＋Ｍ）のモル比率で０．０１～０．２０の量で含むのが好ましく、より好ましくは、０．０２～０．１５であり、さらに好ましくは０．０４～０．１０である。この範囲のモル比であると電池特性において容量が高くなる。その理由は必ずしも明らかではないが、上記範囲において添加した水溶性リチウム化合物との反応性が良好になるためであると推察される。すなわち、Ｌｉ／（Ｎｉ＋Ｍ）比が０．０１以上であると、リチウムが造粒粉末内にも予め存在することになるため焼成時にリチウムを反応に十分に供給することができ、それにより活物質内部にリチウム不足の領域が形成されにくくなるものと考えられる。すなわち、造粒粉末内にリチウムが無い場合、造粒粉末の中心部をリチウムと十分に反応させるためには、リチウムを造粒粉末の外から中心部までの比較的長い距離を拡散させる必要があるが、リチウムが造粒粉末内に予め存在していれば、比較的短い拡散距離で中心部まで到達させることができるので、反応不足の領域が生じやすい中心付近においても十分にリチウムと反応させることができる。また、Ｌｉ／（Ｎｉ＋Ｍ）比が０．１０％以下であると、水溶性リチウム化合物の反応時に発生して造粒粉内に滞在しうるガス（水酸化リチウムの場合は下記式の如く水蒸気が発生）の量を低減して、反応に必要な酸素の相対的な濃度低下を抑制し、それにより酸素が欠損した領域が形成されにくくなるものと考えられる。
＜水酸化リチウムと水酸化物原料粉末との反応の一例＞
　（ＮｉＣｏＡｌ）（ＯＨ）２＋ＬｉＯＨ・Ｈ２Ｏ＋１／４Ｏ２
　　　　　　　　　　　　　　　　　　　→Ｌｉ（ＮｉＣｏＡｌ）Ｏ２＋５／２Ｈ２Ｏ The aqueous slurry preferably contains a water-soluble lithium compound in an amount of 0.01 to 0.20 in terms of a molar ratio of Li / (Ni + M), more preferably 0.02 to 0.15, and even more preferably. Is 0.04 to 0.10. When the molar ratio is in this range, the capacity increases in battery characteristics. The reason is not necessarily clear, but it is presumed that the reactivity with the water-soluble lithium compound added in the above range is improved. That is, when the Li / (Ni + M) ratio is 0.01 or more, lithium is also present in the granulated powder in advance, so that lithium can be sufficiently supplied to the reaction at the time of firing, whereby the active material It is considered that it is difficult to form a lithium-deficient region inside. That is, when there is no lithium in the granulated powder, it is necessary to diffuse lithium over a relatively long distance from the outside of the granulated powder to the central portion in order to sufficiently react the central portion of the granulated powder with lithium. However, if lithium is pre-existing in the granulated powder, it can reach the center with a relatively short diffusion distance, so that it can sufficiently react with lithium even in the vicinity of the center where an insufficiently reactive region is likely to occur. be able to. Further, if the Li / (Ni + M) ratio is 0.10% or less, a gas that is generated during the reaction of the water-soluble lithium compound and can stay in the granulated powder (in the case of lithium hydroxide, water vapor is It is considered that the amount of generation) is reduced to suppress the relative decrease in the concentration of oxygen necessary for the reaction, thereby making it difficult to form a region deficient in oxygen.
<Example of reaction between lithium hydroxide and hydroxide raw material powder>
(NiCoAl) (OH) 2 + LiOH.H 2 O + 1 / 4O 2
　　　　　　　　　　　　　　　　　　　 → Li (NiCoAl) O 2 + 5 / 2H 2 O
　また、前述したとおり、Ｃｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種であって、水酸化物原料粉末に含まれないか又は水酸化物原料粉末において不足する元素の化合物が、スラリーに添加されてもよい。 Further, as described above, it is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn, and Ga, and is not included in the hydroxide raw material powder or hydroxylated. A compound of an element lacking in the raw material powder may be added to the slurry.
（３）乾燥・造粒（三次粒化）工程
　上記スラリーをスプレー乾燥等で乾燥し造粒することにより、空隙を含む略球状の造粒粉末を三次粒粉末として得ることができる。この造粒粉末の粒径は、正極活物質粒子の平均粒子径を決定する直接的な因子となることから、粒子の用途に合わせて適宜設定されるが、タップ密度、プレス密度、電極膜厚等の関係から、体積基準Ｄ５０平均粒径において５～４０μｍ、好ましくは７～４０μｍとするのが一般的である。乾燥・造粒方法としては、原料粉末が充填され、略球状に成形される限り、特に限定はない。 (3) Drying / granulating (tertiary granulation) step By drying and granulating the slurry by spray drying or the like, a substantially spherical granulated powder containing voids can be obtained as a tertiary granulated powder. The particle size of the granulated powder is a direct factor that determines the average particle size of the positive electrode active material particles, and is appropriately set according to the intended use of the particles. Tap density, press density, electrode film thickness In view of the above, the volume-based D50 average particle diameter is generally 5 to 40 μm, preferably 7 to 40 μm. The drying / granulation method is not particularly limited as long as the raw material powder is filled and formed into a substantially spherical shape.
　乾燥時の雰囲気は、特に限定されず、大気雰囲気であっても不活性ガス雰囲気であってもよいが、前述のスラリー化工程において水溶性リチウム化合物を使用した場合においては、窒素、アルゴン等の不活性ガス雰囲気を用いるのが好ましい。これは、スプレー乾燥等による乾燥を大気中で行うと大気中の二酸化炭素に起因して反応性に劣る炭酸リチウムが析出しうるため、焼成工程（リチウム導入工程）におけるリチウム化合物との反応に長時間を要することがあるためである。なお、乾燥の際には、添加した水溶性リチウム化合物が造粒粉末を構成する二次粒子間に析出してバインダーとして機能しうる。 The atmosphere at the time of drying is not particularly limited, and may be an air atmosphere or an inert gas atmosphere. However, when a water-soluble lithium compound is used in the slurrying step described above, nitrogen, argon, etc. It is preferable to use an inert gas atmosphere. This is because it is liable to react with lithium compounds in the firing step (lithium introduction step), because lithium carbonate, which is inferior in reactivity due to carbon dioxide in the air, can be precipitated when spray drying is performed in the air. This is because it may take time. In addition, at the time of drying, the added water-soluble lithium compound may precipitate between secondary particles constituting the granulated powder and function as a binder.
　こうして得られる三次粒粉末としての造粒粉末は、活物質前駆体粉末というべきものであり、そのまま後続のリチウム混合工程（場合により省略可能）及び焼成工程（リチウム導入工程）に付されてもよいし、あるいは、その後購入者によって上記後続の工程が行われる前提の下、活物質前駆体粉末として又はリチウム化合物との混合粉末として商取引されてもよい。 The granulated powder as the tertiary powder obtained in this manner is an active material precursor powder, and may be directly subjected to the subsequent lithium mixing step (can be omitted in some cases) and the firing step (lithium introduction step). Alternatively, it may be traded as an active material precursor powder or as a mixed powder with a lithium compound under the premise that the subsequent process is performed by the purchaser.
（４）リチウム混合工程
　造粒粉末はリチウム化合物と混合されてリチウム混合粉末とされる。リチウム化合物は正極活物質の組成ＬｉＭＯ２を最終的に与えることが可能なあらゆるリチウム含有化合物が使用可能であり、好ましい例としては水酸化リチウム、炭酸リチウム等が挙げられる。反応に先立ち、解砕粉末はリチウム化合物と、乾式混合、湿式混合等の手法により混合されるのが好ましい。リチウム化合物の平均粒子径は特に限定されないが、０．１～５μｍであることが吸湿性の観点からの取扱い容易性及び反応性の観点から好ましい。なお、反応性を高めるために、リチウム量を０．５～４０ｍｏｌ％程度過剰にしてもよい。なお、リチウム混合工程前に仮焼してもよいし、仮焼しなくてもよい。仮焼により、前駆体に含まれる水酸化物基等の熱分解成分を除去することができ、後の焼成工程において、リチウムとの反応性を高めることができる。仮焼温度は４００℃～１０００℃が好ましい。４００℃以上の温度であると十分な熱分解効果が得られる一方、１０００℃以下であると急激な粒成長の進行を抑制して、焼成工程におけるリチウムとの反応性の低下を回避できる。仮焼の雰囲気は、特に限定されず、大気雰囲気であってもよいし、酸素雰囲気であってもよい。 (4) Lithium mixing step The granulated powder is mixed with a lithium compound to form a lithium mixed powder. As the lithium compound, any lithium-containing compound that can finally give the composition LiMO 2 of the positive electrode active material can be used, and preferable examples include lithium hydroxide and lithium carbonate. Prior to the reaction, the pulverized powder is preferably mixed with the lithium compound by a method such as dry mixing or wet mixing. The average particle size of the lithium compound is not particularly limited, but is preferably 0.1 to 5 μm from the viewpoint of ease of handling and reactivity from the viewpoint of hygroscopicity. In order to increase the reactivity, the lithium amount may be excessive by about 0.5 to 40 mol%. In addition, it may be calcined before the lithium mixing step or may not be calcined. By calcining, a thermal decomposition component such as a hydroxide group contained in the precursor can be removed, and the reactivity with lithium can be increased in the subsequent firing step. The calcination temperature is preferably 400 ° C to 1000 ° C. When the temperature is 400 ° C. or higher, a sufficient thermal decomposition effect can be obtained. On the other hand, when the temperature is 1000 ° C. or lower, rapid progress of grain growth can be suppressed, and a decrease in reactivity with lithium in the firing step can be avoided. The calcination atmosphere is not particularly limited, and may be an air atmosphere or an oxygen atmosphere.
　また、前述したとおり、Ｃｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種であって、水酸化物原料粉末に含まれないか又は水酸化物原料粉末において不足する元素の化合物が、造粒粉末に添加されてもよい。 Further, as described above, it is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn, and Ga, and is not included in the hydroxide raw material powder or hydroxylated. A compound of an element lacking in the raw material powder may be added to the granulated powder.
　なお、バインダーとして前述の水溶性リチウム化合物を使用した場合には、上記リチウム混合工程を不要にすることすら可能である。この場合には、スラリー化工程において全必要量の水溶性リチウム化合物を水系スラリーに加えておけばよい。もっとも、必要量の一部の水溶性リチウム化合物を水系スラリーに加えておき、残りの不足分の水溶性リチウム化合物をリチウム混合工程で補填するようにしてもよい。 In addition, when the above-mentioned water-soluble lithium compound is used as a binder, it is possible to eliminate the lithium mixing step. In this case, all the required amount of water-soluble lithium compound may be added to the aqueous slurry in the slurrying step. However, a necessary amount of a part of the water-soluble lithium compound may be added to the aqueous slurry, and the remaining insufficient amount of the water-soluble lithium compound may be compensated in the lithium mixing step.
（５）焼成工程（リチウム導入）
　リチウム混合粉末は焼成されて造粒粉末をリチウム化合物と反応させ、それにより開気孔を備えたリチウム二次電池用正極活物質が得られる。このとき、上述の焼成前混合物を適宜の方法で焼成することで、正極活物質前駆体粒子にリチウムが導入され、それにより正極活物質粒子が得られる。例えば、上述の焼成前混合物を収容した鞘を炉中に投入することで、焼成が行われ得る。この焼成により、正極活物質の合成、さらには粒子の焼結及び粒成長が行われると同時に、略球状の原料粉末二次粒子の粒子間隙間に起因する開気孔が形成される。 (5) Firing step (introducing lithium)
The lithium mixed powder is fired to react the granulated powder with a lithium compound, thereby obtaining a positive electrode active material for a lithium secondary battery having open pores. At this time, lithium is introduce | transduced into positive electrode active material precursor particle | grains by baking the above-mentioned mixture before baking by a suitable method, and, thereby, positive electrode active material particle | grains are obtained. For example, firing can be performed by putting a sheath containing the mixture before firing into a furnace. By this firing, the synthesis of the positive electrode active material, the sintering of the particles, and the grain growth are performed, and at the same time, open pores due to the gaps between the substantially spherical raw material powder secondary particles are formed.
　焼成温度は、６００℃～１１００℃が好ましく、この範囲内であると、粒成長が十分となり、正極活物質の分解やリチウムの揮発を抑制して所望の組成が実現しやすくなる。焼成時間は１～５０時間とするのが好ましく、この範囲であると焼成のために消費されるエネルギーの過度の増大を防止できる。 The firing temperature is preferably 600 ° C. to 1100 ° C. Within this range, grain growth is sufficient, and the desired composition can be easily realized by suppressing decomposition of the positive electrode active material and volatilization of lithium. The firing time is preferably 1 to 50 hours, and if it is within this range, excessive increase in energy consumed for firing can be prevented.
　また、昇温過程において混合したリチウムと前駆体との反応性を高める目的で、焼成温度より低温（例えば４００～６００℃）で１～２０時間の温度保持が行われてもよい。かかる温度保持工程を経ることで、リチウムが溶融するため、反応性を高めることができる。なお、この焼成（リチウム導入）工程における、ある温度域（例えば４００～６００℃）の昇温速度を調整することによっても、同様の効果が得られる。 In addition, for the purpose of increasing the reactivity between the lithium mixed with the precursor and the precursor in the temperature raising process, the temperature may be held at a temperature lower than the firing temperature (for example, 400 to 600 ° C.) for 1 to 20 hours. Since lithium is melted through the temperature holding step, the reactivity can be increased. The same effect can be obtained by adjusting the temperature increase rate in a certain temperature range (for example, 400 to 600 ° C.) in this firing (lithium introduction) step.
　焼成雰囲気は、焼成中に分解が進まないように適宜設定する必要がある。リチウムの揮発が進むような場合は、炭酸リチウム等を同じ鞘内に配置してリチウム雰囲気とすることが好ましい。焼成中に酸素の放出や、さらには還元が進むような場合、酸素分圧の高い雰囲気で焼成することが好ましい。なお、焼成後に、正極活物質粒子同士の癒着や凝集を解したり、正極活物質粒子の平均粒子径を調整したりする目的で、適宜、解砕や分級が行われてもよい。 The firing atmosphere must be set appropriately so that decomposition does not proceed during firing. When the volatilization of lithium proceeds, it is preferable to arrange lithium carbonate or the like in the same sheath to create a lithium atmosphere. When oxygen release or further reduction proceeds during firing, firing is preferably performed in an atmosphere having a high oxygen partial pressure. In addition, after firing, crushing and classification may be appropriately performed for the purpose of releasing adhesion and aggregation between the positive electrode active material particles or adjusting the average particle diameter of the positive electrode active material particles.
　また、焼成後、もしくは解砕や分級工程を経た、正極材活物質において、１００～４００℃で後熱処理を行われても良い。かかる後熱処理工程を行うことで、一次粒子の表面層を改質することができ、以てレート特性及び出力特性が改善される。また、焼成後、もしくは解砕や分級工程を経た、正極活物質に水洗処理が行われてもよい。かかる水洗処理工程を行うことで、正極活物質粉末の表面に残留した未反応のリチウム原料、あるいは大気中の水分及び二酸化炭素が正極活物質粉末表面に吸着して生成する炭酸リチウムを除去することができ、それにより高温保存特性（特にガス発生抑制）が改善される。 In addition, post-heat treatment may be performed at 100 to 400 ° C. in the positive electrode material active material after firing or after being crushed or classified. By performing such a post heat treatment step, the surface layer of the primary particles can be modified, thereby improving the rate characteristics and output characteristics. In addition, the positive electrode active material may be subjected to a water washing treatment after firing or after being crushed or classified. By performing this water washing treatment step, the unreacted lithium raw material remaining on the surface of the positive electrode active material powder or the lithium carbonate produced by the adsorption of moisture and carbon dioxide in the atmosphere on the surface of the positive electrode active material powder is removed. Thereby, the high-temperature storage characteristics (especially gas generation suppression) are improved.
　リチウム二次電池用正極活物質
　上述した本発明の製造方法によれば、高い電池特性をもたらす開気孔比率の高い空隙を備えた、層状岩塩構造を有するリチウム二次電池用正極活物質が得られる。典型的には、本発明により得られる正極活物質は、多数の一次粒子からなる二次粒子が、１～３０％の空隙率及び５０％以上の開気孔比率を有する三次粒子を形成している。空隙率をこの範囲にすることで、容量を損なうことなく充放電特性の改善という効果を得ることができる。正極活物質粒子における開気孔比率は５０％以上であるのが好ましく、より好ましくは６０％以上であり、更に好ましくは７０％であり、特に好ましくは８０％以上であり、最も好ましくは９０％以上である。このように開気孔比率は高ければ高いほど好ましいことから上限値は特に設定されない。このような範囲の空隙率で開気孔比率を高くすることで、開気孔を通って三次粒子内に電解液が浸透しやすくなるためイオン伝導性が向上すると同時に、開気孔以外の部分は多数の一次粒子同士の緻密な結合に起因して電子伝導の経路となる一次粒子間の結合部を十分多く確保することができ、空隙形成に伴う電子伝導性の低下を抑制できる。その結果、本来はトレードオフの関係にある電子伝導性とイオン伝導性の両立が可能となり、改善したレート特性が得られるものと考えられる。 Positive electrode active material for lithium secondary battery According to the production method of the present invention described above, a positive electrode active material for a lithium secondary battery having a layered rock salt structure having voids with a high open pore ratio that provides high battery characteristics can be obtained. . Typically, in the positive electrode active material obtained by the present invention, secondary particles composed of a large number of primary particles form tertiary particles having a porosity of 1 to 30% and an open pore ratio of 50% or more. . By making the porosity within this range, the effect of improving the charge / discharge characteristics can be obtained without impairing the capacity. The open pore ratio in the positive electrode active material particles is preferably 50% or more, more preferably 60% or more, still more preferably 70%, particularly preferably 80% or more, and most preferably 90% or more. It is. Thus, since an open pore ratio is so high that it is preferable, an upper limit is not set in particular. By increasing the open pore ratio with a porosity in such a range, the electrolyte solution easily penetrates into the tertiary particles through the open pores, so that the ion conductivity is improved and at the same time, there are many portions other than the open pores. Due to the dense bonding between the primary particles, a sufficiently large number of bonding portions between the primary particles serving as electron conduction paths can be secured, and the decrease in electron conductivity associated with void formation can be suppressed. As a result, it is considered that both the electron conductivity and the ionic conductivity which are originally in a trade-off relationship can be achieved, and an improved rate characteristic can be obtained.
　本発明の正極活物質を構成する、層状岩塩構造を有するリチウム複合酸化物としては、典型的には、コバルト酸リチウム（ＬｉＣｏＯ２）を用いることができる。もっとも、コバルトの他にニッケルやマンガン等を含有した固溶体を、本発明の正極活物質を構成するリチウム複合酸化物として用いることも可能である。具体的には、本発明の正極活物質を構成するリチウム複合酸化物として、下記の組成式：
　ＬｉｘＮｉ１－ｚＭｚＯ２
（式中、０．９６≦ｘ≦１．０９、０＜ｚ≦０．５）（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表されるものが好ましく利用可能である。ｘの好ましい値は０．９８～１．０６であり、より好ましくは１．００～１．０４である。ｚの好ましい値は０．１５～０．４であり、より好ましくは０．１５～０．２５である。好ましい金属元素ＭはＣｏ、Ａｌ、Ｍｇ及びＭｎからなる群から選択される少なくとも１種又は２種の金属元素であり、より好ましくはＡｌ、Ｍｇ及びＭｎからなる群から選択される少なくとも１種とＣｏとを含み、特に好ましい金属元素Ｍの組合せはＣｏ及びＡｌ、又はＣｏ及びＭｎである。 As the lithium composite oxide having a layered rock salt structure constituting the positive electrode active material of the present invention, lithium cobaltate (LiCoO 2 ) can be typically used. However, it is also possible to use a solid solution containing nickel or manganese in addition to cobalt as the lithium composite oxide constituting the positive electrode active material of the present invention. Specifically, as the lithium composite oxide constituting the positive electrode active material of the present invention, the following composition formula:
Li x Ni 1-z M z O 2
(Wherein 0.96 ≦ x ≦ 1.09, 0 <z ≦ 0.5) (where 0 <y ≦ 0.5, M is Co, Al, Mg, Mn, Ti, Fe, Cr, Those represented by at least one metal element selected from the group consisting of Zn and Ga are preferably usable. A preferable value of x is 0.98 to 1.06, and more preferably 1.00 to 1.04. A preferable value of z is 0.15 to 0.4, and more preferably 0.15 to 0.25. Preferred metal element M is at least one or two metal elements selected from the group consisting of Co, Al, Mg and Mn, more preferably at least one selected from the group consisting of Al, Mg and Mn. A particularly preferred combination of metal elements M containing Co is Co and Al, or Co and Mn.
　さらに、正極活物質の表面（気孔内壁も含む）に、活物質には含まれない金属元素を含む化合物、例えば、Ｗ、Ｍｏ、Ｎｂ、Ｔａ、Ｒｅ等の高価数をとりうる遷移金属を含有する化合物が存在していてもよい。そのような化合物は、Ｗ、Ｍｏ、Ｎｂ、Ｔ　ａ、Ｒｅ等の高価数をとることができる遷移金属とＬｉとの化合物であってもよい。金属元素を含む化合物は、正極活物質内に固溶していてもよいし、第２相として存在していてもよい。こうすることにより、正極活物質と非水電解液との界面が改質され、電荷移動反応が促進されて、出力特性やレート特性が改善されるものと考えられる。 Furthermore, the surface of the positive electrode active material (including the pore inner wall) contains a compound containing a metal element not included in the active material, for example, a transition metal that can take an expensive number such as W, Mo, Nb, Ta, Re, etc. May be present. Such a compound may be a compound of a transition metal capable of taking an expensive number such as W, Mo, Nb, Ta, Re, and Li. The compound containing a metal element may be dissolved in the positive electrode active material or may exist as the second phase. By doing so, it is considered that the interface between the positive electrode active material and the non-aqueous electrolyte is modified, the charge transfer reaction is promoted, and the output characteristics and rate characteristics are improved.
　なお、粒成長の促進、あるいは、焼成中におけるリチウム揮発を考慮して、リチウムが０．１～４０ｍｏｌ％過剰になるように、原料粉末中にリチウム化合物が多めに投入されていてもよい。また、粒成長を促進する目的で、原料粉末に低融点酸化物（酸化ビスマス、酸化バナジウム等）、低融点ガラス（ホウケイ酸ガラス等）、フッ化リチウム塩化リチウム、酸化ホウ素等が、０．００１～３０質量％添加されてもよい。 In addition, considering the promotion of grain growth or the volatilization of lithium during firing, a large amount of lithium compound may be added to the raw material powder so that lithium is in an excess of 0.1 to 40 mol%. For the purpose of promoting grain growth, low melting point oxide (bismuth oxide, vanadium oxide, etc.), low melting point glass (borosilicate glass, etc.), lithium fluoride lithium chloride, boron oxide, etc. are used as the raw material powder. Up to 30% by mass may be added.
　本発明の好ましい態様による正極活物質は、平均一次粒子径が０．０１～５μｍである多数の一次粒子（好ましくは層状岩塩構造を有するリチウム複合酸化物の単結晶一次粒子）からなる二次粒子が三次粒子を形成し、三次粒子が、１～１００μｍの体積基準Ｄ５０平均粒子径、１～３０％の空隙率、５０％以上の開気孔比率、及び０．１～５μｍの平均開気孔径を有し、平均開気孔径で一次粒子の平均粒子径を除した値が０．１～５である。かかる構成を有する正極活物質においては、三次粒子中の気孔の周辺に多数の一次粒子が存在するとともに、隣り合う複数の一次粒子同士で電子伝導及びリチウムイオン拡散の方向（特に電子伝導の方向）が良好に揃う。このため、三次粒子中における電子伝導及びリチウムイオン拡散の経路（特に電子伝導の経路）が良好に確保される。したがって、本発明によれば、従来よりもさらにいっそう電池特性を向上させることが可能となる。特に、ハイレートでの放電電圧（以下、単に「出力特性」と称する）や、ハイレートでの放電容量（以下、単に「レート特性」と称する）を向上させることが可能となる。 The positive electrode active material according to a preferred embodiment of the present invention is a secondary particle comprising a large number of primary particles (preferably a single crystal primary particle of a lithium composite oxide having a layered rock salt structure) having an average primary particle size of 0.01 to 5 μm. Form tertiary particles, and the tertiary particles have a volume-based D50 average particle size of 1 to 100 μm, a porosity of 1 to 30%, an open pore ratio of 50% or more, and an average open pore size of 0.1 to 5 μm. A value obtained by dividing the average particle diameter of primary particles by the average open pore diameter is 0.1 to 5. In the positive electrode active material having such a configuration, a large number of primary particles exist around the pores in the tertiary particles, and the direction of electron conduction and lithium ion diffusion between the adjacent primary particles (particularly the direction of electron conduction). Is well aligned. For this reason, the path | route (especially path | route of electronic conduction) of the electronic conduction and lithium ion diffusion in a tertiary particle is ensured favorably. Therefore, according to the present invention, it is possible to further improve the battery characteristics as compared with the prior art. In particular, it is possible to improve the discharge voltage at high rate (hereinafter simply referred to as “output characteristics”) and the discharge capacity at high rate (hereinafter simply referred to as “rate characteristics”).
　なお、「平均一次粒子径／平均開気孔径」の値が上述のように好ましくは０．１以上５以下、より好ましくは０．２以上３以下、さらに好ましくは０．３以上１以下のとき、三次粒子におけるリチウムイオン伝導性及び電子伝導性が最大限に引き出される。すなわち、「平均一次粒子径／平均開気孔径」の値が０．１以上であると、気孔の周辺に存在する一次粒子の数が多くなり過ぎることによる粒界抵抗の過度の増大を防止して、出力特性やレート特性の低下を防止できる。また、「平均一次粒子径／平均開気孔径」の値が５以下であると、気孔の周辺に存在する一次粒子同士の接触点を多くして、電子伝導及びリチウムイオン拡散の経路（特に電子伝導の経路）を十分に確保して、出力特性の低下を防止できる。 The value of “average primary particle diameter / average open pore diameter” is preferably 0.1 or more and 5 or less, more preferably 0.2 or more and 3 or less, and further preferably 0.3 or more and 1 or less, as described above. In addition, the lithium ion conductivity and the electron conductivity in the tertiary particles are maximized. That is, when the value of “average primary particle diameter / average open pore diameter” is 0.1 or more, excessive increase in grain boundary resistance due to excessive number of primary particles present around the pores is prevented. Thus, it is possible to prevent the output characteristics and rate characteristics from being deteriorated. Further, when the value of “average primary particle diameter / average open pore diameter” is 5 or less, the number of contact points between the primary particles existing around the pores is increased, and electron conduction and lithium ion diffusion paths (especially electrons) Sufficient conduction path) can be secured to prevent degradation of output characteristics.
　また、正極活物質粒子は、多数の気孔、好ましくは開気孔を有している。すなわち、この正極活物質粒子においては、空隙率が１％以上３０％以下であり、平均開気孔径が０．１μｍ以上５μｍ以下である。さらに、この正極活物質粒子においては、単結晶一次粒子の平均粒子径を平均開気孔径で除した値が、０．１以上５以下である。 Moreover, the positive electrode active material particles have a large number of pores, preferably open pores. That is, in the positive electrode active material particles, the porosity is 1% or more and 30% or less, and the average open pore diameter is 0.1 μm or more and 5 μm or less. Furthermore, in this positive electrode active material particle, the value obtained by dividing the average particle size of the single crystal primary particles by the average open pore size is 0.1 or more and 5 or less.
　本実施形態の正極活物質粒子においては、気孔の周辺に多数の単結晶一次粒子が（粒界抵抗が大きくなり過ぎない程度に）存在するとともに、隣り合う複数の単結晶一次粒子同士で電子伝導及びリチウムイオン拡散の方向が良好に揃うのが好ましい。これにより、電子伝導及びリチウムイオン拡散の経路が良好に確保される。よって、単結晶一次粒子間での電子伝導及びリチウムイオン拡散の抵抗が低減され、リチウムイオン伝導性や電子伝導性が向上する。したがって、本実施形態の正極活物質粒子によれば、リチウム二次電池の充放電特性（特にレート特性や出力特性）を顕著に向上させることができる。 In the positive electrode active material particles of the present embodiment, a large number of single crystal primary particles exist around the pores (to the extent that the grain boundary resistance does not become too large), and electron conduction occurs between a plurality of adjacent single crystal primary particles. In addition, it is preferable that the direction of lithium ion diffusion is well aligned. Thereby, the path | route of electronic conduction and lithium ion diffusion is ensured favorably. Therefore, the resistance of electron conduction and lithium ion diffusion between single crystal primary particles is reduced, and lithium ion conductivity and electron conductivity are improved. Therefore, according to the positive electrode active material particles of this embodiment, the charge / discharge characteristics (particularly rate characteristics and output characteristics) of the lithium secondary battery can be significantly improved.
　さらに、正極活物質粒子（三次粒子）を構成する二次粒子は、用いた水酸化物原料に由来して、電子伝導及びリチウムイオン拡散が行われる（００３）面が二次粒子の中心から外方に向かって並んでいる。このため、電解液と接する、外表面や開気孔により形成される内表面におけるリチウムイオン出入り面および電子伝導面の露出が増大するとともに、二次粒子内の電子伝導、及びリチウムイオン拡散の抵抗も低減されうる。特に、二次粒子は典型的には略球状であるため隣り合う二次粒子の接点で放射状配向が略同一方向に揃いやすく、それだけ電子伝導及びリチウムイオン拡散の方向（特に電子伝導の方向）が二次粒子同士間においても良好に揃いやすい。このような観点からも、三次粒子中における電子伝導及びリチウムイオン拡散の経路（特に電子伝導の経路）を確保しやすいといえる。 Further, the secondary particles constituting the positive electrode active material particles (tertiary particles) are derived from the used hydroxide raw material, and the (003) plane where electron conduction and lithium ion diffusion are performed is outside the center of the secondary particles. They are lined up towards. For this reason, the exposure of the lithium ion entrance / exit surface and the electron conduction surface on the inner surface formed by the outer surface and open pores that are in contact with the electrolytic solution is increased, and the electron conduction in the secondary particles and the resistance of lithium ion diffusion are also increased. Can be reduced. In particular, since the secondary particles are typically substantially spherical, the radial orientation is likely to be aligned in substantially the same direction at the contact point between adjacent secondary particles, and the direction of electron conduction and lithium ion diffusion (especially the direction of electron conduction) is accordingly increased. It is easy to arrange well between secondary particles. From this point of view, it can be said that it is easy to ensure the path of electron conduction and lithium ion diffusion (particularly the path of electron conduction) in the tertiary particles.
　単結晶一次粒子の平均粒子径は、０．０１μｍ以上５μｍ以下であるのが好ましく、０．０１μｍ以上３μｍ以下であることがより好ましく、０．０１μｍ以上１．５μｍ以下であることがさらに好ましい。単結晶一次粒子の平均粒子径を上記の範囲内とすることで、単結晶一次粒子の結晶性が確保される。この点、単結晶一次粒子の平均粒子径が０．１μｍ未満であると、単結晶一次粒子の結晶性が低下し、リチウム二次電池の出力特性やレート特性が低下する場合がある。しかしながら、本実施形態の正極活物質粒子においては、単結晶一次粒子の平均粒子径が０．１～０．０１μｍであっても、出力特性やレート特性の大きな低下は見られない。 The average particle size of the single crystal primary particles is preferably 0.01 μm or more and 5 μm or less, more preferably 0.01 μm or more and 3 μm or less, and further preferably 0.01 μm or more and 1.5 μm or less. By setting the average particle diameter of the single crystal primary particles within the above range, the crystallinity of the single crystal primary particles is ensured. In this respect, if the average particle size of the single crystal primary particles is less than 0.1 μm, the crystallinity of the single crystal primary particles may be reduced, and the output characteristics and rate characteristics of the lithium secondary battery may be reduced. However, in the positive electrode active material particles of the present embodiment, even if the average particle size of the single crystal primary particles is 0.1 to 0.01 μm, no significant reduction in output characteristics or rate characteristics is observed.
　三次粒子としての正極活物質粒子の平均粒子径（体積基準Ｄ５０平均粒径）は、１μｍ以上１００μｍ以下であるのが好ましく、より好ましくは２μｍ以上７０μｍ以下であり、さらに好ましくは３μｍ以上５０μｍ以下であり、特に好ましくは５μｍ～４０μｍであり、最も好ましくは１０～２０μｍである。正極活物質粒子の平均粒子径をこの範囲内とすることで、正極活物質粒子内における正極活物質の充填性が確保される（充填率が向上する）。また、リチウム二次電池の出力特性やレート特性を維持しつつ、平坦な電極表面を形成することができる。一方、正極活物質粒子の平均粒子径が上記範囲内であると、正極活物質の充填率を高くすることができるとともに、リチウム二次電池の出力特性やレート特性の低下や電極表面の平坦性の低下を防止することができる。正極活物質粒子の平均粒子径の分布は、シャープであってもよく、ブロードであってもよく、ピークを複数有していてもよい。例えば、正極活物質粒子の平均粒子径の分布がシャープでない場合は、正極活物質層内の正極活物質の充填密度を高めたり、正極活物質層と正極集電体との密着力を高めたりすることができる。これにより、充放電特性をさらに改善することができる。特に、水溶性リチウム化合物を含むスラリーをバインダー兼リチウム源として使用した場合には、上記範囲内（特に５μｍ～４０μｍ）の平均粒径を有する正極活物質を安定的に得やすくなる。 The average particle diameter (volume-based D50 average particle diameter) of the positive electrode active material particles as the tertiary particles is preferably 1 μm or more and 100 μm or less, more preferably 2 μm or more and 70 μm or less, and further preferably 3 μm or more and 50 μm or less. It is particularly preferably 5 μm to 40 μm, most preferably 10 to 20 μm. By setting the average particle diameter of the positive electrode active material particles within this range, the filling property of the positive electrode active material in the positive electrode active material particles is ensured (the filling rate is improved). In addition, a flat electrode surface can be formed while maintaining the output characteristics and rate characteristics of the lithium secondary battery. On the other hand, when the average particle diameter of the positive electrode active material particles is within the above range, the filling rate of the positive electrode active material can be increased, and the output characteristics and rate characteristics of the lithium secondary battery are deteriorated and the flatness of the electrode surface is increased. Can be prevented. The distribution of the average particle diameter of the positive electrode active material particles may be sharp, broad, or have a plurality of peaks. For example, when the average particle size distribution of the positive electrode active material particles is not sharp, the packing density of the positive electrode active material in the positive electrode active material layer is increased, or the adhesion between the positive electrode active material layer and the positive electrode current collector is increased. can do. Thereby, charge / discharge characteristics can be further improved. In particular, when a slurry containing a water-soluble lithium compound is used as a binder and lithium source, a positive electrode active material having an average particle diameter within the above range (especially from 5 μm to 40 μm) can be obtained stably.
　正極活物質粒子における空隙率（気孔の体積比率）は、１％以上３０％以下であるのが好ましい。空隙率をこの範囲にすることで、容量を損なうことなく充放電特性の改善という効果を得ることができる。特に、本発明の方法によれば低い空隙率（例えば１０％以下）でも高い開気孔比率を実現可能であるとの利点がある。正極活物質粒子における開気孔比率は５０％以上であるのが好ましく、より好ましくは６０％以上であり、更に好ましくは７０％以上であり、特に好ましくは８０％以上であり、最も好ましくは９０％以上である。正極活物質粒子における平均開気孔径（正極活物質粒子内の開気孔の直径の平均値）は、０．１μｍ以上５μｍ以下であるのが好ましく、より好ましくは０．２μｍ以上３μｍ以下、さらに好ましくは０．４μｍ以上３μｍ以下である。このような範囲であると、比較的大きな気孔の生成を防止して、充放電に寄与する正極活物質の体積あたりの量を十分に確保することができる。また、このような大きな気孔の局所において、応力集中が発生するのを防止して、内部で応力を均一に開放する効果が得られる。さらに、導電材や電解質を内在させやすくなり、気孔による応力開放効果を十分なものとすることができる。このため、高容量を維持しつつ充放電特性を改善するという効果が期待できる。 The porosity (volume ratio of pores) in the positive electrode active material particles is preferably 1% or more and 30% or less. By making the porosity within this range, the effect of improving the charge / discharge characteristics can be obtained without impairing the capacity. In particular, according to the method of the present invention, there is an advantage that a high open pore ratio can be realized even with a low porosity (for example, 10% or less). The open pore ratio in the positive electrode active material particles is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, and most preferably 90%. That's it. The average open pore diameter in the positive electrode active material particles (average diameter of open pores in the positive electrode active material particles) is preferably 0.1 μm or more and 5 μm or less, more preferably 0.2 μm or more and 3 μm or less. Is 0.4 μm or more and 3 μm or less. Within such a range, generation of relatively large pores can be prevented, and a sufficient amount per volume of the positive electrode active material contributing to charge / discharge can be secured. Further, it is possible to prevent the stress concentration from occurring locally in such large pores and to release the stress uniformly inside. Furthermore, it becomes easy to contain a conductive material and an electrolyte, and the stress releasing effect by the pores can be made sufficient. For this reason, the effect of improving the charge / discharge characteristics while maintaining a high capacity can be expected.
　正極活物質は、２．５～３．１ｇ／ｃｃのタップ密度を有するのが好ましく、より好ましくは２．６～３．０ｇ／ｃｃである。このような範囲のタップ密度は正極活物質として高密度であることを意味するため、体積エネルギー密度が高い正極活物質をもたらす。 The positive electrode active material preferably has a tap density of 2.5 to 3.1 g / cc, more preferably 2.6 to 3.0 g / cc. A tap density in such a range means that the positive electrode active material has a high density, and thus a positive electrode active material having a high volumetric energy density is brought about.
　正極活物質は、１．０ｋｇｆ／ｃｍ２の圧力で一軸プレスした際のプレス密度が、３．０～３．５ｇ／ｃｃであることが好ましく、より好ましくは３．２～３．４ｇ／ｃｃである。このような範囲のプレス密度は、電極形成した際に高密度であることを意味するため、体積エネルギー密度が高い正極活物質をもたらす。このプレス密度は、直径２０ｍｍの円筒ダイスに正極活物質を１．５ｇ秤量し、１．０ｋｇｆ／ｃｍ２の荷重で一軸プレスした後、（粉末重量）／（プレス後の粉末の嵩体積）を算出することによって決定することができる。 The positive electrode active material preferably has a press density of 3.0 to 3.5 g / cc, more preferably 3.2 to 3.4 g / cc when uniaxially pressed at a pressure of 1.0 kgf / cm 2. It is. A press density in such a range means that a high density is obtained when the electrode is formed, resulting in a positive electrode active material having a high volumetric energy density. This press density is obtained by weighing 1.5 g of the positive electrode active material on a cylindrical die having a diameter of 20 mm, uniaxially pressing with a load of 1.0 kgf / cm 2 , and then (powder weight) / (bulk volume of pressed powder). It can be determined by calculating.
　活物質前駆体粉末
　本発明の一態様によれば、リチウムイオン電池用正極活物質の製造に用いられる活物質前駆体粉末が提供される。この活物質前駆体粉末は、製造方法に関して前述した、水酸化物原料粉末、水溶性リチウム化合物、及び所望により原料微粒子を含んでなる凝集粒子からなる粉末である。すなわち、水酸化物原料粉末は、Ｎｉ１－ｙＭｙ（ＯＨ）２（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表される組成の一次粒子が多数凝集した二次粒子からなり、一次粒子の少なくとも一部が二次粒子の中心から外方に向かって放射状に並んでなるものである。原料微粒子は、水酸化物原料粉末及び微粒子の合計量に対して０～２５質量％以下の量の、水酸化物原料粉末と同様の組成及び水酸化物原料粉末よりも小さい粒径を有する任意成分である。水溶性リチウム化合物は、二次粒子間及び／又は二次粒子及び原料微粒子間に介在し、リチウム源として機能するのみならず水酸化物原料粉末の二次粒子同士を結着させて三次粒子とするためのバインダーとしても機能する。このように、活物質前駆体粉末は、前述した正極活物質の製造方法における「（３）乾燥・造粒（三次粒化）工程」で得られる造粒粉末に相当する。したがって、「リチウム二次電池用正極活物質の製造方法」において述べた、水酸化物原料粉末、水溶性リチウム化合物、及び原料微粒子に関する記載は、本態様の活物質前駆体粉末にもそのまま援用するものとする。 Active Material Precursor Powder According to one embodiment of the present invention, there is provided an active material precursor powder that is used in the production of a positive electrode active material for a lithium ion battery. This active material precursor powder is a powder comprising the hydroxide raw material powder, the water-soluble lithium compound, and optionally aggregated particles containing the raw material fine particles as described above with respect to the production method. That is, the hydroxide raw material powder is Ni 1-y M y (OH) 2 (where 0 <y ≦ 0.5, M is Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga). At least one metal element selected from the group consisting of secondary particles in which a large number of primary particles are aggregated, and at least part of the primary particles are directed outward from the center of the secondary particles. Are arranged in a radial pattern. The raw material fine particles have the same composition as the hydroxide raw material powder and a particle size smaller than that of the hydroxide raw material powder in an amount of 0 to 25% by mass or less based on the total amount of the hydroxide raw material powder and the fine particles. It is an ingredient. The water-soluble lithium compound is interposed between the secondary particles and / or between the secondary particles and the raw material fine particles, and not only functions as a lithium source but also binds the secondary particles of the hydroxide raw material powder to the tertiary particles. It also functions as a binder. Thus, the active material precursor powder corresponds to the granulated powder obtained in the “(3) drying / granulation (tertiary granulation) step” in the method for producing a positive electrode active material described above. Therefore, the description regarding the hydroxide raw material powder, the water-soluble lithium compound, and the raw material fine particles described in “Method for producing positive electrode active material for lithium secondary battery” is also incorporated into the active material precursor powder of this embodiment as it is. Shall.
　また、本態様の活物質前駆体粉末は、焼成によるリチウム導入を経て正極活物質とされた場合に、１０～４０μｍ、好ましくは１０～２０μｍの体積基準Ｄ５０平均粒径を有する。この焼成によるリチウム導入の手法は、一般的なリチウム導入及び焼成手法に従えばよいが、より正確な評価を行うためには、必要に応じてリチウム化合物を添加した後、高純度アルミナ製のるつぼ内に投入し、酸素雰囲気中（０．１ＭＰａ）にて５０℃／ｈで昇温し、７６５℃で２４時間加熱処理することにより行うのが好ましい。こうして得られた正極活物質の体積基準Ｄ５０平均粒径をレーザ回折／散乱式粒度分布測定装置により水を分散媒として測定すればよい。 Further, the active material precursor powder of this embodiment has a volume-based D50 average particle diameter of 10 to 40 μm, preferably 10 to 20 μm, when converted into a positive electrode active material through the introduction of lithium by firing. The method of introducing lithium by firing may be in accordance with general lithium introduction and firing methods. However, for more accurate evaluation, after adding a lithium compound as necessary, a crucible made of high-purity alumina is used. It is preferable to carry out heat treatment in an oxygen atmosphere (0.1 MPa) at a rate of 50 ° C./h and heat treatment at 765 ° C. for 24 hours. What is necessary is just to measure the volume reference | standard D50 average particle diameter of the positive electrode active material obtained in this way by a laser diffraction / scattering type particle size distribution measuring apparatus by using water as a dispersion medium.
　さらに、本態様の活物質前駆体粉末は、水中で超音波照射により解凝集された場合に、体積基準で、粒径１．０μｍ以下の粒子の割合が０～４０％、好ましくは１０～３０％であり、粒径１．０～５．０μｍの粒子の割合が６０～１００％、好ましくは７０～９０％である粒度分布を有する。この解凝集は、水中での超音波照射による一般的な解凝集手法に従えばよいが、より正確な評価を行うためには、活物質前駆体粉末を水中に投入後、超音波ホモジナイザーにより６００Ｗで３分間超音波照射を行い、水酸化物原料粉末及び原料微粒子の状態にほぐすことにより行うのが好ましい。こうして得られた試料スラリーの粒度分布をレーザ回折／散乱式粒度分布測定装置を用いて測定すればよい。 Furthermore, when the active material precursor powder of this embodiment is deaggregated in water by ultrasonic irradiation, the proportion of particles having a particle size of 1.0 μm or less on a volume basis is 0 to 40%, preferably 10 to 30%. The particle size distribution is such that the proportion of particles having a particle size of 1.0 to 5.0 μm is 60 to 100%, preferably 70 to 90%. This deagglomeration may be carried out in accordance with a general deagglomeration technique by ultrasonic irradiation in water. However, in order to perform a more accurate evaluation, after putting the active material precursor powder into water, it is 600 W using an ultrasonic homogenizer. It is preferable to carry out by irradiating with ultrasonic waves for 3 minutes to loosen the hydroxide raw material powder and raw material fine particles. The particle size distribution of the sample slurry thus obtained may be measured using a laser diffraction / scattering particle size distribution measuring device.
　上記のように焼成ないし解凝集して粒度分布特性を評価しているのは、活物質前駆体粉末は焼成に付される前の前駆体粉末であるため、そのままの形態で平均粒径や粒度分布を一義的に決定することは容易ではないため、より客観的な評価手法が望ましいとの考えに基づくものである。そして、上記範囲内の粒度分布特性によって特性付けられる本態様の活物質前駆体粉末は、（所望によるリチウム化合物との混合後）焼成によりリチウム導入するだけで、造孔剤を使用することなく、高い電池特性をもたらす、所望の空隙率で開気孔比率の高い正極活物質を極めて簡便に得ることができる。 The reason why the particle size distribution characteristics are evaluated by firing or deaggregating as described above is that the active material precursor powder is the precursor powder before being subjected to firing, so the average particle size and particle size in the form as they are. Since it is not easy to determine the distribution uniquely, it is based on the idea that a more objective evaluation method is desirable. And the active material precursor powder of this embodiment characterized by the particle size distribution characteristics within the above range can be obtained by simply introducing lithium by firing (after mixing with a lithium compound as desired) without using a pore-forming agent, A positive electrode active material having a desired porosity and a high open pore ratio that provides high battery characteristics can be obtained very simply.
　水溶性リチウム化合物の好ましい例としては、水酸化リチウム、硝酸リチウム、塩化リチウム、酸化リチウム、及び過酸化リチウムが挙げられ、より好ましくは、バインダー効果が高く、かつ、反応性が高くリチウム導入しやすい点で水酸化リチウムである。 Preferable examples of the water-soluble lithium compound include lithium hydroxide, lithium nitrate, lithium chloride, lithium oxide, and lithium peroxide. More preferably, the binder effect is high, the reactivity is high, and lithium can be easily introduced. In terms of lithium hydroxide.
　凝集粒子は、水溶性リチウム化合物をＬｉ／（Ｎｉ＋Ｍ）のモル比率で０．０１～０．２０の量で含むのが好ましく、より好ましくは、０．０２～０．１５であり、さらに好ましくは０．０４～０．１０である。前述したように、この範囲のモル比であると電池特性において容量が高くなる。 Aggregated particles preferably contain a water-soluble lithium compound in a molar ratio of Li / (Ni + M) of 0.01 to 0.20, more preferably 0.02 to 0.15, and even more preferably. 0.04 to 0.10. As described above, when the molar ratio is within this range, the capacity increases in battery characteristics.
　活物質前駆体粉末は、焼成によるリチウム導入を経て正極活物質とされた場合に、１～３０％の空隙率及び５０％以上の開気孔比率を有するのが好ましい。より好ましい空隙率は３～２０％であり、さらに好ましくは５～１５％である。より好ましい開気孔比率は６０％以上であり、更に好ましくは７０％以上であり、特に好ましくは８０％以上であり、最も好ましくは９０％以上である。活物質前駆体粉末は、焼成によるリチウム導入を経て正極活物質とされた場合に、０．２～３μｍの平均開気孔径を有するのが好ましく、より好ましくは０．４～３μｍである。活物質前駆体粉末は、正極活物質を構成する一次粒子の平均粒子径を平均開気孔径で除した値が０．２～３であるのが好ましく、より好ましくは０．３～１である。これらの数値範囲内であることの利点は正極活物質に関して前述したとおりである。 The active material precursor powder preferably has a porosity of 1 to 30% and an open pore ratio of 50% or more when converted into a positive electrode active material through the introduction of lithium by firing. A more preferable porosity is 3 to 20%, and further preferably 5 to 15%. A more preferable open pore ratio is 60% or more, further preferably 70% or more, particularly preferably 80% or more, and most preferably 90% or more. The active material precursor powder preferably has an average open pore size of 0.2 to 3 μm, more preferably 0.4 to 3 μm, when converted into a positive electrode active material through the introduction of lithium by firing. The active material precursor powder preferably has a value obtained by dividing the average particle diameter of the primary particles constituting the positive electrode active material by the average open pore diameter of 0.2 to 3, more preferably 0.3 to 1. . The advantages of being within these numerical ranges are as described above for the positive electrode active material.
　本発明を以下の例によってさらに具体的に説明する。また、各種物性値の測定方法、及び諸特性の評価方法は、以下に示す通りである。 The present invention will be described more specifically with reference to the following examples. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are as showing below.
＜Ｄ５０粒径＞
　水酸化物原料粉末、造粒粉末（活物質前駆体粉末）及び正極活物質の平均粒子径は、レーザ回折／散乱式粒度分布測定装置（例えば、日機装株式会社製　型番「ＭＴ３０００－ＩＩ」）を用いて、水を分散媒として測定される体積基準Ｄ５０平均粒子径（メディアン径）を測定した。 <D50 particle size>
The average particle size of the hydroxide raw material powder, granulated powder (active material precursor powder), and positive electrode active material is determined using a laser diffraction / scattering type particle size distribution measuring device (for example, model number “MT3000-II” manufactured by Nikkiso Co., Ltd.). The volume-based D50 average particle diameter (median diameter) measured using water as a dispersion medium was measured.
＜粒径１．０μｍ以下の粒子の割合＞
　造粒粉末（活物質前駆体粉末）を水中に投入後、超音波ホモジナイザー（株式会社日本精機製作所製、ＵＳ－６００Ｔ）により６００Ｗで３分間超音波照射を行い、水酸化物原料粉末及び原料微粒子の状態にほぐした。こうして得られた試料スラリーの粒度分布を、レーザ回折／散乱式粒度分布測定装置（例えば、日機装株式会社製　型番「ＭＴ３０００－ＩＩ」）を用いて測定し、全構成粒子中に占める粒径１．０μｍ以下の粒子の割合を決定した。 <Percentage of particles having a particle size of 1.0 μm or less>
After putting the granulated powder (active material precursor powder) into water, ultrasonic irradiation is performed for 3 minutes at 600 W with an ultrasonic homogenizer (Nippon Seiki Seisakusho, US-600T), hydroxide raw material powder and raw material fine particles I relaxed to the state of. The particle size distribution of the sample slurry thus obtained was measured using a laser diffraction / scattering particle size distribution measuring apparatus (for example, model number “MT3000-II” manufactured by Nikkiso Co., Ltd.). The proportion of particles below 0 μm was determined.
＜空隙率＞
　正極材料活物質を樹脂埋めし、クロスセクションポリッシャ（ＣＰ）により正極活物質の断面研磨面が観察できるように研磨し、ＳＥＭ（走査型子顕微鏡、「ＪＳＭ－６３９０ＬＡ」日本電子社製）により、断面イメージを取得する。このイメージを画像処理により、断面中の空隙部分と正極材料部分を分け、（空隙部分の面積）／（空隙部分の面積＋正極材料の面積）を求める。これを、１０個の２次粒子に対して行い、その平均値を求め、空隙率（％）とした。 <Porosity>
The positive electrode material active material is filled with resin, and polished so that the cross-section polished surface of the positive electrode active material can be observed with a cross section polisher (CP). By SEM (scanning microscope, “JSM-6390LA” manufactured by JEOL Ltd.), Get a cross-sectional image. This image is subjected to image processing to divide the void portion and the positive electrode material portion in the cross section, and obtain (area of void portion) / (area of void portion + area of positive electrode material). This was performed with respect to ten secondary particles, and the average value thereof was obtained as the porosity (%).
＜開気孔比率＞
　上述の空隙率の評価法において、空隙部分のうち樹脂が含浸されている部分を開気孔、空隙部分のうち樹脂が含浸されていない部分を閉気孔とし（開気孔部分の面積）／（開気孔部分の面積＋閉機構部分の面積）によって求める。これを、１０個の２次粒子に対して行い、その平均値を求め、開気孔比率とした。なお、樹脂埋めの際には、開気孔中に十分に樹脂が含浸されるよう、真空含浸装置（ストルアス社製　装置名「シトバック」）を用いて気孔中に存在する空気を十分に追い出しながら樹脂埋めを行った。 <Open pore ratio>
In the porosity evaluation method described above, the portion of the void portion that is impregnated with the resin is the open pore, and the portion of the void portion that is not impregnated with the resin is the closed pore (area of the open pore portion) / (open pore) (Area of the portion + area of the closing mechanism portion). This was performed on 10 secondary particles, and the average value thereof was obtained as the open pore ratio. When filling the resin, use a vacuum impregnation device (device name “Sitback” manufactured by Struers) to sufficiently impregnate the open pores with the resin while sufficiently expelling the air present in the pores. Filled.
＜平均開気孔径＞
　平均開気孔径（平均開気孔径）は、水銀圧入式細孔分布測定装置（株式会社島津製作所製、装置名「オートポアＩＶ９５１０」）を用いた水銀圧入法によって測定した。 <Average open pore size>
The average open pore diameter (average open pore diameter) was measured by a mercury intrusion method using a mercury intrusion pore distribution measuring apparatus (manufactured by Shimadzu Corporation, apparatus name “Autopore IV9510”).
＜一次粒子径／平均開気孔径＞
　ＦＥ－ＳＥＭ（電界放射型走査型電子顕微鏡：日本電子株式会社製、製品名「ＪＳＭ－７０００Ｆ」）を用いて、単結晶一次粒子が視野内に１０個以上入る倍率を選択して、ＳＥＭ画像を撮影した。このＳＥＭ画像において、１０個の一次粒子のそれぞれについて、外接円を描いたときの当該外接円の直径を求めた。そして、得られた１０個の直径の平均値を、一次粒子径とした。この一次粒子径を平均開気孔径で除して、一次粒子径／平均開気孔径の比率を得た。 <Primary particle size / average open pore size>
Using a FE-SEM (field emission scanning electron microscope: manufactured by JEOL Ltd., product name “JSM-7000F”), a magnification at which 10 or more single crystal primary particles enter the field of view is selected, and an SEM image Was taken. In this SEM image, for each of the 10 primary particles, the diameter of the circumscribed circle when the circumscribed circle was drawn was determined. And the average value of the obtained 10 diameter was made into the primary particle diameter. The primary particle size was divided by the average open pore size to obtain a ratio of primary particle size / average open pore size.
＜タップ密度＞
　正極活物質粒子の粉末試料を入れたメスシリンダーを市販のタップ密度測定装置を用いて２００回タッピングした後、（粉末重量）／（粉末の嵩体積）を算出することによって、タップ密度を求めた。 <Tap density>
After tapping a graduated cylinder containing a powder sample of positive electrode active material particles 200 times using a commercially available tap density measuring device, the tap density was determined by calculating (powder weight) / (bulk volume of powder). .
＜放電容量及びＳＯＣ１０％電圧＞
　電池特性の評価のために、次のようにしてコインセル型電池を作製した。具体的には、得られた三次粒粉末、アセチレンブラック、及びポリフッ化ビニリデン（ＰＶＤＦ）を、質量比で９０：５：５となるように混合し、Ｎ－メチル－２－ピロリドンに分散させることで、正極活物質ペーストを作製した。このペーストを正極集電体としての厚さ２０μｍのアルミニウム箔上に均一な厚さ（乾燥後の厚さ５０μｍ）となるように塗布し、乾燥後のシートから直径１４ｍｍの円板状に打ち抜いたものを２０００ｋｇ／ｃｍ２の圧力でプレスすることで、正極板を作製した。このようにして作製した正極板を用いてコインセルを作製した。なお、電解液は、エチレンカーボネート（ＥＣ）及びジエチルカーボネート（ＤＥＣ）を等体積比で混合した有機溶媒に、ＬｉＰＦ６を１ｍｏｌ／Ｌの濃度となるように溶解することで調製した。 <Discharge capacity and SOC 10% voltage>
In order to evaluate the battery characteristics, a coin cell type battery was produced as follows. Specifically, the obtained tertiary particle powder, acetylene black, and polyvinylidene fluoride (PVDF) are mixed at a mass ratio of 90: 5: 5 and dispersed in N-methyl-2-pyrrolidone. Thus, a positive electrode active material paste was prepared. This paste was applied on an aluminum foil having a thickness of 20 μm as a positive electrode current collector so as to have a uniform thickness (thickness after drying: 50 μm), and punched out into a disk shape having a diameter of 14 mm from the dried sheet. A positive electrode plate was produced by pressing the product at a pressure of 2000 kg / cm 2 . A coin cell was manufactured using the positive electrode plate thus manufactured. The electrolytic solution was prepared by dissolving LiPF 6 in an organic solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at an equal volume ratio to a concentration of 1 mol / L.
　上述のように作製した特性評価用電池（コインセル）を用いて、以下のように充放電操作を行うことで、出力特性の評価を行った。具体的には、０．１Ｃレートの電流値で電池電圧が４．３Ｖとなるまで定電流充電した。その後、電池電圧を４．３Ｖに維持する電流条件で、その電流値が１／２０に低下するまで定電圧充電した。１０分間休止した後、５Ｃレートの電流値で電池電圧が２．５Ｖになるまで定電流放電し、その後１０分間休止した。これらの充放電操作を１サイクルとし、２５℃の条件下で合計２サイクル繰り返した。２サイクル目の放電容量の値を測定結果として採用した。２サイクル目の放電容量を１００％とした際の９０％時の放電電圧（ＳＯＣ１０％電圧：ＳＯＣは「Ｓｔａｔｅ　Ｏｆ　Ｃｈａｒｇｅ」の略であって充電状態を意味する）を放電曲線から読み取った。この数値を出力特性の指標とした。この数値が高いほど、出力特性が高く、好ましい。 Using the battery for characteristic evaluation (coin cell) produced as described above, the output characteristic was evaluated by performing a charge / discharge operation as follows. Specifically, constant current charging was performed until the battery voltage reached 4.3 V at a current value of 0.1 C rate. Thereafter, constant voltage charging was performed until the current value decreased to 1/20 under the current condition of maintaining the battery voltage at 4.3V. After resting for 10 minutes, the battery was discharged at a constant current at a current value of 5C until the battery voltage reached 2.5 V, and then rested for 10 minutes. These charging / discharging operations were defined as 1 cycle, and the cycle was repeated for 2 cycles under the condition of 25 ° C. The value of the discharge capacity at the second cycle was adopted as the measurement result. The discharge voltage at 90% when the discharge capacity at the second cycle was 100% (SOC 10% voltage: SOC is an abbreviation for “State Of Charge” and means a state of charge) was read from the discharge curve. This value was used as an index of output characteristics. The higher this value, the higher the output characteristics, which is preferable.
　例１：造孔剤を使用した比較例
（１）水酸化物原料粉末の作製
　組成が（Ｎｉ０．８４４Ｃｏ０．１５６）（ＯＨ）２であり、二次粒子がほぼ球状且つ一次粒子の一部が二次粒子の中心から外方向へ放射状に並んだ、表１に示される二次粒子径（Ｄ５０）を有するニッケル・コバルト複合水酸化物粉末を用意した。このニッケル・コバルト複合水酸化物粉末は公知の技術に従って作製可能なものであり、例えば以下のようにして作製した。すなわち、純水２０Ｌを入れた反応槽へ、モル比でＮｉ：Ｃｏ＝８４．４：１５．６である濃度１ｍｏｌ／Ｌの硫酸ニッケルと硫酸コバルトの混合水溶液を投入速度５０ｍｌ／ｍｉｎで、また濃度３ｍｏｌ／Ｌの硫酸アンモニウムを投入速度２ｍｌ／ｍｉｎで同時に連続投入した。一方、濃度１０ｍｏｌ／Ｌの水酸化ナトリウム水溶液を、反応槽内のｐＨが自動的に１２．５に維持されるように投入した。反応槽内の温度は７０℃に維持し、攪拌機により常に攪拌した。生成したニッケル・コバルト複合水酸化物は、オーバーフロー管からオーバーフローさせて取り出し、水洗、脱水、乾燥処理した。 Example 1 : Comparative example using a pore-forming agent (1) Preparation of hydroxide raw material powder The composition is (Ni 0.844 Co 0.156 ) (OH) 2 and the secondary particles are almost spherical and primary particles. A nickel-cobalt composite hydroxide powder having a secondary particle diameter (D50) shown in Table 1 in which some of the particles are arranged radially outward from the center of the secondary particles was prepared. This nickel-cobalt composite hydroxide powder can be produced according to a known technique. For example, it was produced as follows. That is, a mixed aqueous solution of nickel sulfate and cobalt sulfate having a molar ratio of Ni: Co = 84.4: 15.6 in a molar ratio of 1 mol / L to a reaction vessel containing 20 L of pure water at a charging rate of 50 ml / min. Ammonium sulfate having a concentration of 3 mol / L was continuously continuously fed at a feeding rate of 2 ml / min. On the other hand, an aqueous sodium hydroxide solution having a concentration of 10 mol / L was added so that the pH in the reaction vessel was automatically maintained at 12.5. The temperature in the reaction vessel was maintained at 70 ° C., and was always stirred with a stirrer. The produced nickel / cobalt composite hydroxide was taken out by overflowing from the overflow tube, washed with water, dehydrated, and dried.
（２）スラリー調製工程
　上述のように作製した水酸化物原料粉末に対し、モル比でＮｉ：Ｃｏ：Ａｌ＝８１：１５：４となるようにＡｌ原料であるベーマイトを加えた後、分散媒として純水４００部を加え、ボールミルにより２４時間粉砕し、一次粒子とした。これに対し、造孔剤（球状：エアウォーター株式会社製、商品名「ベルパールＲ１００」）を、添加後の粉末総重量に対する割合が２％となるよう添加し、さらにバインダー（ポリビニルアルコール：品番ＶＰ－１８、日本酢ビ・ポバール株式会社製）１部と、分散剤（製品名「マリアリムＫＭ－０５２１」、日油株式会社製）１部と、消泡剤（１－オクタノール：和光純薬工業株式会社製）０．５部を添加後、ボールミルにより２４時間混合した。この混合物を、減圧下で撹拌することで脱泡するとともに、粘度を０．５Ｐａ・ｓ（ブルックフィールド社製ＬＶＴ型粘度計を用いて測定）に調整することで、スラリーを調製した。 (2) Slurry preparation step After adding boehmite which is an Al raw material to the hydroxide raw material powder produced as described above so that the molar ratio is Ni: Co: Al = 81: 15: 4, a dispersion medium is added. As a primary particle, 400 parts of pure water was added and ground with a ball mill for 24 hours. On the other hand, a pore-forming agent (spherical: manufactured by Air Water Co., Ltd., trade name “Bellpearl R100”) was added so that the ratio to the total powder weight after addition was 2%, and a binder (polyvinyl alcohol: product number VP) -18, 1 part of Nippon Vinegar Pover Co., Ltd.), 1 part of dispersant (product name “Marialim KM-0521”, manufactured by NOF Corporation) and antifoaming agent (1-octanol: Wako Pure Chemical Industries, Ltd.) After adding 0.5 part), the mixture was mixed with a ball mill for 24 hours. The mixture was degassed by stirring under reduced pressure, and a slurry was prepared by adjusting the viscosity to 0.5 Pa · s (measured using an LVT viscometer manufactured by Brookfield).
（３）乾燥・造粒工程
　上述のようにして調製したスラリーをスプレードライヤー（大川原化工機株式会社製、型式「ＦＯＣ－１６」、熱風入り口温度１２０℃、アトマイザ回転数２４０００ｒｐｍ）で乾燥・造粒することにより、略球状の二次粒造粒粉末作製した。乾燥後のＤ５０粒径は、１７μｍであった。造粒した粉末を５０℃／ｈで５００℃まで昇温し、５００℃で３時間保持することにより仮焼成を行った。 (3) Drying and granulating step The slurry prepared as described above is dried and granulated with a spray dryer (Okawara Kako Co., Ltd., model “FOC-16”, hot air inlet temperature 120 ° C., atomizer rotational speed 24000 rpm). By doing so, a substantially spherical secondary granulated powder was produced. The D50 particle size after drying was 17 μm. The granulated powder was heated to 50 ° C./h up to 500 ° C., and held at 500 ° C. for 3 hours to carry out temporary firing.
（４）リチウム化合物との混合
　仮焼した粉末と、ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）とを、ｍｏｌ比率でＬｉ／（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）＝１．０４となるように混合した。 (4) Mixing with Lithium Compound The calcined powder and LiOH.H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.) in a molar ratio of Li / (Ni 0.81 Co 0.15 Al 0.04 ) = 1.04.
（５）焼成工程（リチウム導入工程）
　上述の混合粉末を、高純度アルミナ製のるつぼ内に投入し、酸素雰囲気中（０．１ＭＰａ）にて５０℃／ｈで昇温し、７６５℃で２４時間加熱処理することで、Ｌｉ（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）Ｏ２粉末を得た。こうして得られた正極活物質について各種測定を行ったところ表１に示されるとおりの結果が得られた。 (5) Firing step (lithium introduction step)
The above mixed powder is put into a crucible made of high-purity alumina, heated at 50 ° C./h in an oxygen atmosphere (0.1 MPa), and heat-treated at 765 ° C. for 24 hours to obtain Li (Ni 0.81 Co 0.15 Al 0.04 ) O 2 powder was obtained. When various measurements were performed on the positive electrode active material thus obtained, the results shown in Table 1 were obtained.
　例２～７：造孔剤を使用しない例（三次粒化）
（１）水酸化物原料粉末の作製
　例１と同様の方法に準拠しつつ諸条件を適宜変えることにより、組成が（Ｎｉ０．８４４Ｃｏ０．１５６）（ＯＨ）２であり、二次粒子がほぼ球状且つ一次粒子の一部が二次粒子の中心から外方向へ放射状に並んだ、表１に示される二次粒子径（Ｄ５０）を有する各種のニッケル・コバルト複合水酸化物粉末を用意した。 Examples 2 to 7 : Examples in which no pore forming agent is used (tertiary granulation)
(1) Preparation of hydroxide raw material powder The composition is (Ni 0.844 Co 0.156 ) (OH) 2 by appropriately changing various conditions in accordance with the same method as in Example 1, and the secondary particles Prepared various nickel-cobalt composite hydroxide powders with secondary particle size (D50) shown in Table 1 in which the particles are almost spherical and some of the primary particles are arranged radially outward from the center of the secondary particles. did.
（２）スラリー調製工程
　例２～４においては、得られた水酸化物原料粉末にＡｌ原料であるベーマイトを加えた粉末１００部を分散媒としての純水３００部と、二次粒子が粉砕されないように攪拌混合した。一方、例５～７においては、得られた水酸化物原料粉末及びその原料微粉末を表１に示される混合比で含んでなる混合粉末にＡｌ原料であるベーマイトを加えた粉末１００部を分散媒としての純水３００部と混合した。なお、例５～７で用いた原料微粉末は、水酸化物原料粉末を例１と同様にボールミルにより２４時間粉砕して得たものである。また、例２～７において、ベーマイトの添加量は、混合粉末におけるモル比でＮｉ：Ｃｏ：Ａｌ＝８１：１５：４となるような量とした。こうして得られた混合物を、減圧下で撹拌することで脱泡するとともに、粘度を０．５Ｐａ・ｓ（ブルックフィールド社製ＬＶＴ型粘度計を用いて測定）に調整することで、スラリーを調製した。 (2) Slurry Preparation Step In Examples 2 to 4, 100 parts of powder obtained by adding boehmite, which is an Al raw material, to the obtained hydroxide raw material powder, 300 parts of pure water as a dispersion medium, and secondary particles are not pulverized. Were mixed with stirring. On the other hand, in Examples 5 to 7, 100 parts of powder obtained by adding boehmite, which is an Al raw material, to a mixed powder containing the obtained hydroxide raw material powder and the raw material fine powder in a mixing ratio shown in Table 1 were dispersed. Mixed with 300 parts of pure water as a medium. The raw material fine powder used in Examples 5 to 7 was obtained by grinding hydroxide raw material powder with a ball mill for 24 hours in the same manner as in Example 1. In Examples 2 to 7, the amount of boehmite added was such that the molar ratio in the mixed powder was Ni: Co: Al = 81: 15: 4. The mixture thus obtained was defoamed by stirring under reduced pressure, and the viscosity was adjusted to 0.5 Pa · s (measured using a Brookfield LVT viscometer) to prepare a slurry. .
（３）乾燥・造粒工程（三次粒化工程）
　上述のようにして調製したスラリーを例１と同様の方法により、乾燥・造粒することにより、略球状の三次粒造粒粉末を得た。乾燥後のＤ５０粒径は、１７μｍであった。 (3) Drying / granulating process (tertiary granulating process)
The slurry prepared as described above was dried and granulated in the same manner as in Example 1 to obtain a substantially spherical tertiary granulated powder. The D50 particle size after drying was 17 μm.
（４）リチウム化合物との混合および（５）焼成工程（リチウム導入工程）は例１と同様の方法により行った。こうして得られた正極活物質について各種測定を行ったところ表１に示されるとおりの結果が得られた。 (4) Mixing with the lithium compound and (5) calcination step (lithium introduction step) were carried out in the same manner as in Example 1. When various measurements were performed on the positive electrode active material thus obtained, the results shown in Table 1 were obtained.
　例２～７で得られた正極活物質はいずれも、平均一次粒子径が０．０１～５μｍである多数の一次粒子からなる三次粒子を含んでなり、三次粒子が、１０～４０μｍの体積基準Ｄ５０平均粒子径、１～３０％の空隙率、５０％以上の開気孔比率、及び０．２～３μｍの平均開気孔径を有し、平均開気孔径で一次粒子の平均粒子径を除した値が０．２～３、タップ密度２．５ｇ／ｃｃ以上であった。 Each of the positive electrode active materials obtained in Examples 2 to 7 includes tertiary particles composed of a large number of primary particles having an average primary particle diameter of 0.01 to 5 μm, and the tertiary particles have a volume basis of 10 to 40 μm. D50 has an average particle diameter of 1-30%, an open pore ratio of 50% or more, and an average open pore diameter of 0.2-3 μm, and the average primary pore diameter is divided by the average open pore diameter. The value was 0.2 to 3, and the tap density was 2.5 g / cc or more.
　例８及び９：造孔剤を使用しない例（三次粒化、スラリー調製工程でリチウム化合物を添加）
（１）水酸化物原料粉末の作製
　例１と同様の方法に準拠しつつ諸条件を適宜変えることにより、組成が（Ｎｉ０．８４４Ｃｏ０．１５６）（ＯＨ）２であり、二次粒子がほぼ球状且つ一次粒子の一部が二次粒子の中心から外方向へ放射状に並んだ、表１に示される二次粒子径（Ｄ５０）を有する各種のニッケル・コバルト複合水酸化物粉末を用意した。 Examples 8 and 9 : Example in which no pore-forming agent was used (addition of lithium compound in tertiary granulation and slurry preparation process)
(1) Preparation of hydroxide raw material powder The composition is (Ni 0.844 Co 0.156 ) (OH) 2 by appropriately changing various conditions in accordance with the same method as in Example 1, and the secondary particles Prepared various nickel-cobalt composite hydroxide powders with secondary particle size (D50) shown in Table 1 in which the particles are almost spherical and some of the primary particles are arranged radially outward from the center of the secondary particles. did.
（２）スラリー調製工程
　得られた水酸化物原料粉末にＡｌ原料であるベーマイトを加えた粉末１００部を、分散媒としての純水３００部と二次粒子が粉砕されないように攪拌混合した後、ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）を混合及び溶解した。なお、ベーマイトの添加量は混合粉末におけるモル比でＮｉ：Ｃｏ：Ａｌ＝８１：１５：４となるような量とした。また、例８においては、ｍｏｌ比率でＬｉ／（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）＝０．４０となるように、例９においては、ｍｏｌ比率でＬｉ／（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）＝１．０４となるようにＬｉＯＨ・Ｈ２Ｏ粉末を用いた。こうして得られた混合物を、減圧下で撹拌することで脱泡するとともに、粘度を０．５Ｐａ・ｓ（ブルックフィールド社製ＬＶＴ型粘度計を用いて測定）に調整することで、スラリーを調製した。 (2) Slurry preparation process After stirring and mixing 100 parts of powder obtained by adding boehmite which is an Al raw material to the obtained hydroxide raw material powder, so that secondary particles are not pulverized with 300 parts of pure water as a dispersion medium, LiOH · H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.) was mixed and dissolved. The amount of boehmite added was such that the molar ratio in the mixed powder was Ni: Co: Al = 81: 15: 4. In Example 8, Li / (Ni 0.81 Co 0.15 Al 0.04 ) = 0.40 in terms of mol ratio, and in Example 9, Li / (Ni 0.81 in terms of mol ratio). LiOH · H 2 O powder was used so that Co 0.15 Al 0.04 ) = 1.04. The mixture thus obtained was defoamed by stirring under reduced pressure, and the viscosity was adjusted to 0.5 Pa · s (measured using a Brookfield LVT viscometer) to prepare a slurry. .
（３）乾燥・造粒工程（三次粒化工程）
　上述のようにして調製したスラリーを例１と同様の方法により、乾燥・造粒することにより、略球状の三次粒造粒粉末を得た。乾燥後のＤ５０粒径は、１７μｍであった。 (3) Drying / granulating process (tertiary granulating process)
The slurry prepared as described above was dried and granulated in the same manner as in Example 1 to obtain a substantially spherical tertiary granulated powder. The D50 particle size after drying was 17 μm.
（４）リチウム化合物との混合
　例８においては、乾燥した造粒粉末と、ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）とを、混合後のｍｏｌ比率でＬｉ／（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）＝１．０４となるように、Ｌｉ／（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）＝０．６４の比率で混合した。例９においては、ＬｉＯＨ・Ｈ２Ｏ粉末をスラリー調製工程において、ｍｏｌ比率でＬｉ／（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）＝１．０４となるよう混合したため、乾燥した造粒粉末とリチウム化合物の混合は行わなかった。 (4) Mixing with Lithium Compound In Example 8, Li / (Ni 0 .2) in a mol ratio after mixing dried granulated powder and LiOH.H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.) . It was mixed at a ratio of Li / (Ni 0.81 Co 0.15 Al 0.04 ) = 0.64 so that 81 Co 0.15 Al 0.04 ) = 1.04. In Example 9, since LiOH.H 2 O powder was mixed in the slurry preparation step so that the molar ratio was Li / (Ni 0.81 Co 0.15 Al 0.04 ) = 1.04, dry granulation was performed. The powder and the lithium compound were not mixed.
（５）焼成工程（リチウム導入工程）は例１と同様の方法により行った。こうして得られた正極活物質について各種測定を行ったところ表１に示されるとおりの結果が得られた。 (5) The firing step (lithium introduction step) was performed in the same manner as in Example 1. When various measurements were performed on the positive electrode active material thus obtained, the results shown in Table 1 were obtained.
　例８及び９で得られた正極活物質はいずれも、平均一次粒子径が０．０１～５μｍである多数の一次粒子からなる三次粒子を含んでなり、三次粒子が、１０～４０μｍの体積基準Ｄ５０平均粒子径、１～３０％の空隙率、５０％以上の開気孔比率、及び０．２～３μｍの平均開気孔径を有し、平均開気孔径で一次粒子の平均粒子径を除した値が０．２～３、タップ密度２．５ｇ／ｃｃ以上であった。 Each of the positive electrode active materials obtained in Examples 8 and 9 includes tertiary particles composed of a large number of primary particles having an average primary particle diameter of 0.01 to 5 μm, and the tertiary particles are based on a volume of 10 to 40 μm. D50 has an average particle diameter of 1-30%, an open pore ratio of 50% or more, and an average open pore diameter of 0.2-3 μm, and the average primary pore diameter is divided by the average open pore diameter. The value was 0.2 to 3, and the tap density was 2.5 g / cc or more.
　例１０～１３：造孔剤を使用しない例（三次粒化、スラリー調製工程でリチウム化合物を添加）
　例８において「（２）スラリー調製工程」において、ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）の混合量を、ｍｏｌ比率でＬｉ／（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）が０．０１（例１０）、０．０５（例１１）、０．１０（例１２）又は０．１５（例１３）となるように、さらに「（４）リチウム化合物との混合」において、乾燥した造粒粉末と、ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）とを、Ｌｉ／（Ｎｉ０．８１Ｃｏ０．１５Ａｌ０．０４）が１．０３（例１０）、０．９９（例１１）、０．９４（例１２）又は０．８９（例１３）の比率で混合した以外は、例８と同様の方法で正極活物質の作製及び評価を行った。結果は表１に示されるとおりであった。 Examples 10 to 13 : Examples in which no pore-forming agent is used (tertiary granulation, addition of lithium compound in the slurry preparation process)
In Example 8, in “(2) Slurry preparation process”, the mixing amount of LiOH · H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.) was expressed in terms of a molar ratio of Li / (Ni 0.81 Co 0.15 Al 0. 04 ) becomes 0.01 (Example 10), 0.05 (Example 11), 0.10 (Example 12) or 0.15 (Example 13), and further "(4) Mixing with lithium compound" , Dried granulated powder and LiOH.H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.), Li / (Ni 0.81 Co 0.15 Al 0.04 ) 1.03 (Example 10) ), 0.99 (Example 11), 0.94 (Example 12) or 0.89 (Example 13), except that the positive electrode active material was prepared and evaluated in the same manner as in Example 8. . The results were as shown in Table 1.
　例１０～１３で得られた正極活物質はいずれも、平均一次粒子径が０．０１～５μｍである多数の一次粒子からなる三次粒子を含んでなり、三次粒子が、１０～４０μｍの体積基準Ｄ５０平均粒子径、１～３０％の空隙率、５０％以上の開気孔比率、及び０．２～３μｍの平均開気孔径を有し、平均開気孔径で一次粒子の平均粒子径を除した値が０．２～３、タップ密度２．５ｇ／ｃｃ以上であった。 Each of the positive electrode active materials obtained in Examples 10 to 13 includes tertiary particles composed of a large number of primary particles having an average primary particle diameter of 0.01 to 5 μm, and the tertiary particles are based on a volume of 10 to 40 μm. D50 has an average particle diameter of 1-30%, an open pore ratio of 50% or more, and an average open pore diameter of 0.2-3 μm, and the average primary pore diameter is divided by the average open pore diameter. The value was 0.2 to 3, and the tap density was 2.5 g / cc or more.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　例１４：造孔剤を使用した比較例
（１）水酸化物原料粉末の作製
　組成が（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）（ＯＨ）２であり、二次粒子がほぼ球状且つ一次粒子の一部が二次粒子の中心から外方向へ放射状に並んだ、表２に示される二次粒子径（Ｄ５０）を有するニッケル・コバルト・マンガン複合水酸化物粉末を用意した。このニッケル・コバルト・マンガン複合水酸化物粉末は公知の技術に従って作製可能なものであり、例えば以下のようにして作製した。すなわち、純水２０Ｌを入れた反応槽へ、モル比でＮｉ：Ｃｏ：Ｍｎ＝５０：２０：３０である濃度１ｍｏｌ／Ｌの硫酸ニッケル、硫酸コバルト及び硫酸マンガンの混合水溶液を投入速度５０ｍｌ／ｍｉｎで、また濃度３ｍｏｌ／Ｌの硫酸アンモニウムを投入速度２ｍｌ／ｍｉｎで同時に連続投入した。一方、濃度１０ｍｏｌ／Ｌの水酸化ナトリウム水溶液を、反応槽内のｐＨが自動的に１２．５に維持されるように投入した。反応槽内の温度は７０℃に維持し、攪拌機により常に攪拌した。生成したニッケル・コバルト・マンガン複合水酸化物は、オーバーフロー管からオーバーフローさせて取り出し、水洗、脱水、乾燥処理した。なお、反応槽への上記各化合物の投入から水酸化物の取り出しに至るまでの一連の工程（すなわち水洗、脱水及び乾燥処理を除く一連の工程）はいずれも不活性雰囲気中で行った。 Example 14 : Comparative example using a pore-forming agent (1) Preparation of hydroxide raw material powder The composition is (Ni 0.5 Co 0.2 Mn 0.3 ) (OH) 2 and the secondary particles are almost spherical. In addition, a nickel / cobalt / manganese composite hydroxide powder having a secondary particle diameter (D50) shown in Table 2 in which some of the primary particles are arranged radially outward from the center of the secondary particles was prepared. This nickel-cobalt-manganese composite hydroxide powder can be produced according to a known technique, and for example, produced as follows. That is, a mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate having a concentration of 1 mol / L in a molar ratio of Ni: Co: Mn = 50: 20: 30 is charged into a reaction vessel containing 20 L of pure water at a rate of 50 ml / min. In addition, ammonium sulfate having a concentration of 3 mol / L was continuously charged simultaneously at a charging rate of 2 ml / min. On the other hand, an aqueous sodium hydroxide solution having a concentration of 10 mol / L was added so that the pH in the reaction vessel was automatically maintained at 12.5. The temperature in the reaction vessel was maintained at 70 ° C., and was always stirred with a stirrer. The produced nickel-cobalt-manganese composite hydroxide was taken out by overflowing from the overflow tube, washed with water, dehydrated and dried. In addition, all of a series of steps (i.e., a series of steps excluding water washing, dehydration and drying treatment) from the introduction of each compound into the reaction vessel to the removal of the hydroxide was performed in an inert atmosphere.
（２）スラリー調製工程
　上述のように作製した水酸化物原料粉末に対し、分散媒として純水４００部を加え、ボールミルにより２４時間粉砕し、一次粒子とした。これに対し、造孔剤（球状：エアウォーター株式会社製、商品名「ベルパールＲ１００」）を、添加後の粉末総重量に対する割合が２％となるよう添加し、さらにバインダー（ポリビニルアルコール：品番ＶＰ－１８、日本酢ビ・ポバール株式会社製）１部と、分散剤（製品名「マリアリムＫＭ－０５２１」、日油株式会社製）１部と、消泡剤（１－オクタノール：和光純薬工業株式会社製）０．５部を添加後、ボールミルにより２４時間混合した。この混合物を、減圧下で撹拌することで脱泡するとともに、粘度を０．５Ｐａ・ｓ（ブルックフィールド社製ＬＶＴ型粘度計を用いて測定）に調整することで、スラリーを調製した。 (2) Slurry Preparation Step 400 parts of pure water was added as a dispersion medium to the hydroxide raw material powder produced as described above, and pulverized with a ball mill for 24 hours to obtain primary particles. On the other hand, a pore-forming agent (spherical: manufactured by Air Water Co., Ltd., trade name “Bellpearl R100”) was added so that the ratio to the total powder weight after addition was 2%, and a binder (polyvinyl alcohol: product number VP) -18, 1 part of Nippon Vinegar Pover Co., Ltd.), 1 part of dispersant (product name “Marialim KM-0521”, manufactured by NOF Corporation) and antifoaming agent (1-octanol: Wako Pure Chemical Industries, Ltd.) After adding 0.5 part), the mixture was mixed with a ball mill for 24 hours. The mixture was degassed by stirring under reduced pressure, and a slurry was prepared by adjusting the viscosity to 0.5 Pa · s (measured using an LVT viscometer manufactured by Brookfield).
（３）乾燥・造粒工程
　上述のようにして調製したスラリーをスプレードライヤー（大川原化工機株式会社製、型式「ＦＯＣ－１６」、熱風入り口温度１２０℃、アトマイザ回転数２４０００ｒｐｍ）で乾燥・造粒することにより、略球状の二次粒造粒粉末作製した。造粒した粉末を５０℃／ｈで５００℃まで昇温し、５００℃で３時間保持することにより仮焼成を行った。 (3) Drying and granulating step The slurry prepared as described above is dried and granulated with a spray dryer (Okawara Kako Co., Ltd., model “FOC-16”, hot air inlet temperature 120 ° C., atomizer rotational speed 24000 rpm). By doing so, a substantially spherical secondary granulated powder was produced. The granulated powder was heated to 50 ° C./h up to 500 ° C., and held at 500 ° C. for 3 hours to carry out temporary firing.
（４）リチウム化合物との混合
　仮焼した粉末と、ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）とを、ｍｏｌ比率でＬｉ／（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）＝１．０４となるように混合した。 (4) Mixing with Lithium Compound The calcined powder and LiOH · H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.) are in a molar ratio of Li / (Ni 0.5 Co 0.2 Mn 0.3 ) = 1.04.
（５）焼成工程（リチウム導入工程）
　上述の混合粉末を、高純度アルミナ製のるつぼ内に投入し、大気雰囲気中で５０℃／ｈで昇温し、８５０℃で２４時間加熱処理することで、Ｌｉ（（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）Ｏ２粉末を得た。こうして得られた正極活物質について各種測定を行ったところ表２に示されるとおりの結果が得られた。 (5) Firing step (lithium introduction step)
The above mixed powder is put into a crucible made of high-purity alumina, heated at 50 ° C./h in an air atmosphere, and heat-treated at 850 ° C. for 24 hours, whereby Li ((Ni 0.5 Co 0 .2 Mn 0.3 ) O 2 powder was obtained, and various measurements were performed on the positive electrode active material thus obtained, and the results shown in Table 2 were obtained.
　例１５～２０：造孔剤を使用しない例（三次粒化）
（１）水酸化物原料粉末の作製
　例１４と同様の方法に準拠しつつ諸条件を適宜変えることにより、組成が（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）（ＯＨ）２であり、二次粒子がほぼ球状且つ一次粒子の一部が二次粒子の中心から外方向へ放射状に並んだ、表２に示される二次粒子径（Ｄ５０）を有する各種のニッケル・コバルト・マンガン複合水酸化物粉末を用意した。 Examples 15 to 20 : Examples in which no pore forming agent is used (tertiary granulation)
(1) Preparation of hydroxide raw material powder The composition is (Ni 0.5 Co 0.2 Mn 0.3 ) (OH) 2 by appropriately changing various conditions in accordance with the same method as in Example 14. Various nickel-cobalt-manganese composites having secondary particle diameters (D50) shown in Table 2 in which the secondary particles are substantially spherical and part of the primary particles are arranged radially outward from the center of the secondary particles. A hydroxide powder was prepared.
（２）スラリー調製工程
　例１５～１７においては、得られた水酸化物原料粉末１００部を分散媒としての純水３００部と、二次粒子が粉砕されないように攪拌混合した。一方、例１８～２０においては、得られた水酸化物原料粉末及びその原料微粉末を表２に示される混合比で含んでなる混合粉末１００部を分散媒としての純水３００部と混合した。なお、例１８～２０で用いた原料微粉末は、水酸化物原料粉末を例１４と同様にボールミルにより２４時間粉砕して得たものである。こうして得られた混合物を、減圧下で撹拌することで脱泡するとともに、粘度を０．５Ｐａ・ｓ（ブルックフィールド社製ＬＶＴ型粘度計を用いて測定）に調整することで、スラリーを調製した。 (2) Slurry Preparation Step In Examples 15 to 17, 100 parts of the obtained hydroxide raw material powder was mixed with 300 parts of pure water as a dispersion medium with stirring so that secondary particles were not pulverized. On the other hand, in Examples 18 to 20, 100 parts of a mixed powder comprising the obtained hydroxide raw material powder and the raw material fine powder in a mixing ratio shown in Table 2 was mixed with 300 parts of pure water as a dispersion medium. . The raw material fine powder used in Examples 18 to 20 was obtained by pulverizing hydroxide raw material powder with a ball mill for 24 hours in the same manner as in Example 14. The mixture thus obtained was defoamed by stirring under reduced pressure, and the viscosity was adjusted to 0.5 Pa · s (measured using a Brookfield LVT viscometer) to prepare a slurry. .
（３）乾燥・造粒工程（三次粒化工程）
　上述のようにして調製したスラリーを例１４と同様の方法により、乾燥・造粒することにより、略球状の三次粒造粒粉末を得た。 (3) Drying / granulating process (tertiary granulating process)
The slurry prepared as described above was dried and granulated by the same method as in Example 14 to obtain a substantially spherical tertiary granulated powder.
（４）リチウム化合物との混合および（５）焼成工程（リチウム導入工程）は例１４と同様の方法により行った。こうして得られた正極活物質について各種測定を行ったところ表２に示されるとおりの結果が得られた。 (4) Mixing with the lithium compound and (5) calcination step (lithium introduction step) were carried out in the same manner as in Example 14. When various measurements were performed on the positive electrode active material thus obtained, the results shown in Table 2 were obtained.
　例２１～２６：造孔剤を使用しない例（三次粒化、スラリー調製工程でリチウム化合物を添加）
（１）水酸化物原料粉末の作製
　例１４と同様の方法に準拠しつつ諸条件を適宜変えることにより、組成が（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）（ＯＨ）２であり、二次粒子がほぼ球状且つ一次粒子の一部が二次粒子の中心から外方向へ放射状に並んだ、表２に示される二次粒子径（Ｄ５０）を有する各種のニッケル・コバルト・マンガン複合水酸化物粉末を用意した。 Examples 21 to 26 : Examples in which no pore-forming agent is used (tertiary granulation, addition of lithium compound in the slurry preparation process)
(1) Preparation of hydroxide raw material powder The composition is (Ni 0.5 Co 0.2 Mn 0.3 ) (OH) 2 by appropriately changing various conditions in accordance with the same method as in Example 14. Various nickel-cobalt-manganese composites having secondary particle diameters (D50) shown in Table 2 in which the secondary particles are substantially spherical and part of the primary particles are arranged radially outward from the center of the secondary particles. A hydroxide powder was prepared.
（２）スラリー調製工程
　得られた水酸化物原料粉末１００部を、分散媒としての純水３００部と二次粒子が粉砕されないように攪拌混合した後、ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）を混合及び溶解した。このとき、ｍｏｌ比率でＬｉ／（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）＝０．０１（例２１）、０．０５（例２２）、０．１０（例２３）、０．１５（例２４）、０．４０（例２５）又は１．０４（例２６）となるように、ＬｉＯＨ・Ｈ２Ｏ粉末を用いた。こうして得られた混合物を、減圧下で撹拌することで脱泡するとともに、粘度を０．５Ｐａ・ｓ（ブルックフィールド社製ＬＶＴ型粘度計を用いて測定）に調整することで、スラリーを調製した。 (2) Slurry preparation process After stirring and mixing 100 parts of the obtained hydroxide raw material powder and 300 parts of pure water as a dispersion medium and secondary particles are not crushed, LiOH · H 2 O powder (Wako Pure Chemical Industries, Ltd.) Kogyo Co., Ltd.) was mixed and dissolved. At this time, the molar ratio of Li / (Ni 0.5 Co 0.2 Mn 0.3 ) = 0.01 (Example 21), 0.05 (Example 22), 0.10 (Example 23), 0.15 LiOH.H 2 O powder was used so as to be (Example 24), 0.40 (Example 25), or 1.04 (Example 26). The mixture thus obtained was defoamed by stirring under reduced pressure, and the viscosity was adjusted to 0.5 Pa · s (measured using a Brookfield LVT viscometer) to prepare a slurry. .
（３）乾燥・造粒工程（三次粒化工程）
　上述のようにして調製したスラリーを例１４と同様の方法により、乾燥・造粒することにより、略球状の三次粒造粒粉末を得た。 (3) Drying / granulating process (tertiary granulating process)
The slurry prepared as described above was dried and granulated by the same method as in Example 14 to obtain a substantially spherical tertiary granulated powder.
（４）リチウム化合物との混合
　乾燥した造粒粉末と、ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）とを、混合後のｍｏｌ比率で（Ｌｉ／（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）＝１．０４となるように、Ｌｉ／（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）＝１．０３（例２１）、０．９９（例２２）、０．９４（例２３）、０．８９（例２４）又は０．６４（例２５）の比率で混合した。例２６においては、ＬｉＯＨ・Ｈ２Ｏ粉末をスラリー調製工程において、ｍｏｌ比率でＬｉ／（Ｎｉ０．5Ｃｏ０．2Ｍｎ０．３）＝１．０４となるよう混合したため、乾燥した造粒粉末とリチウム化合物の混合は行わなかった。 (4) Mixing with Lithium Compound Dry granulated powder and LiOH.H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.) are mixed in a molar ratio (Li / (Ni 0.5 Co 0.5 ) . 2 Mn 0.3 ) = 1.04 Li / (Ni 0.5 Co 0.2 Mn 0.3 ) = 1.03 (Example 21), 0.99 (Example 22), 0. 94 (Example 23), 0.89 (Example 24) or 0.64 (Example 25) were mixed at a ratio of 26. In Example 26, LiOH.H 2 O powder was mixed at a molar ratio of Li / (H / O) in the slurry preparation step. Ni 0.5 Co 0.2 Mn 0.3 ) = 1.04 was mixed so that the dried granulated powder and the lithium compound were not mixed.
（５）焼成工程（リチウム導入工程）は例１４と同様の方法により行った。こうして得られた正極活物質について各種測定を行ったところ表２に示されるとおりの結果が得られた。 (5) The firing step (lithium introduction step) was performed in the same manner as in Example 14. When various measurements were performed on the positive electrode active material thus obtained, the results shown in Table 2 were obtained.
　例１５～２６で得られた正極活物質はいずれも、平均一次粒子径が０．０１～５μｍである多数の一次粒子からなる三次粒子を含んでなり、三次粒子が、１０～４０μｍの体積基準Ｄ５０平均粒子径、１～３０％の空隙率、５０％以上の開気孔比率、及び０．２～３μｍの平均開気孔径を有し、平均開気孔径で一次粒子の平均粒子径を除した値が０．２～３、タップ密度２．５ｇ／ｃｃ以上であった。 Each of the positive electrode active materials obtained in Examples 15 to 26 includes tertiary particles composed of a large number of primary particles having an average primary particle diameter of 0.01 to 5 μm, and the tertiary particles are based on a volume of 10 to 40 μm. D50 has an average particle diameter of 1-30%, an open pore ratio of 50% or more, and an average open pore diameter of 0.2-3 μm, and the average primary pore diameter is divided by the average open pore diameter. The value was 0.2 to 3, and the tap density was 2.5 g / cc or more.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002

Claims (20)

  1. 　リチウムイオン電池用正極活物質の製造方法であって、
    　Ｎｉ１－ｙＭｙ（ＯＨ）２（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表される組成の一次粒子が多数凝集した二次粒子からなり、前記一次粒子の少なくとも一部が前記二次粒子の中心から外方に向かって放射状に並んでなる、水酸化物原料粉末又はその凝集物を用意する工程と、
    　前記水酸化物原料粉末を用いて又は前記凝集物を解砕して用いて、前記水酸化物原料粉末を含むスラリーを調製する工程と、
    　前記スラリーを用いて略球状の造粒粉末を作製する工程と、
    　前記造粒粉末にリチウム化合物を混合してリチウム混合粉末を得る工程と、
    　前記リチウム混合粉末を焼成して前記造粒粉末とリチウム化合物を反応させ、それにより開気孔を備えたリチウム二次電池用正極活物質を得る工程と、
    を含んでなる方法。     A method for producing a positive electrode active material for a lithium ion battery,
    Ni 1-y M y (OH) 2 (where 0 <y ≦ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles. Preparing a hydroxide raw material powder or an aggregate thereof;
    Using the hydroxide raw material powder or pulverizing the aggregate to prepare a slurry containing the hydroxide raw material powder; and
    Producing a substantially spherical granulated powder using the slurry;
    Mixing the lithium compound with the granulated powder to obtain a lithium mixed powder;
    Firing the lithium mixed powder to react the granulated powder with a lithium compound, thereby obtaining a positive active material for a lithium secondary battery having open pores;
    Comprising a method.
  2. 　前記水酸化物原料粉末が、１～５μｍの体積基準Ｄ５０平均粒径を有する、請求項１に記載の方法。 The method according to claim 1, wherein the hydroxide raw material powder has a volume-based D50 average particle diameter of 1 to 5 µm.
  3. 　前記スラリーが、１０ｎｍ～７００ｎｍの体積基準Ｄ５０平均粒径を有する原料微粒子を更に含む、請求項１又は２に記載の方法。 The method according to claim 1 or 2, wherein the slurry further comprises raw material fine particles having a volume-based D50 average particle diameter of 10 nm to 700 nm.
  4. 　前記原料粉末及び前記原料微粒子の合計量に対する前記原料微粒子の比率が、２５質量％以下である、請求項３に記載の方法。 The method according to claim 3, wherein a ratio of the raw material fine particles to a total amount of the raw material powder and the raw material fine particles is 25% by mass or less.
  5. 　前記造粒粉末及び前記リチウム混合粉末が、造孔剤を含まない、請求項１～４のいずれか一項に記載の方法。 The method according to any one of claims 1 to 4, wherein the granulated powder and the lithium mixed powder do not contain a pore forming agent.
  6. 　前記リチウム二次電池用正極活物質が、多数の一次粒子からなる二次粒子を含んでなり、前記二次粒子が、１～３０％の空隙率及び５０％以上の開気孔比率を有する、請求項１～５のいずれか一項に記載の方法。 The positive electrode active material for a lithium secondary battery includes secondary particles composed of a large number of primary particles, and the secondary particles have a porosity of 1 to 30% and an open pore ratio of 50% or more. Item 6. The method according to any one of Items 1 to 5.
  7. 　前記スラリーが、水系スラリーである、請求項１～６のいずれか一項に記載の方法。 The method according to any one of claims 1 to 6, wherein the slurry is an aqueous slurry.
  8. 　前記水系スラリーが、水溶性リチウム化合物を更に含む、請求項７に記載の方法。 The method according to claim 7, wherein the aqueous slurry further contains a water-soluble lithium compound.
  9. 　前記水溶性リチウム化合物が、水酸化リチウムである、請求項８に記載の方法。 The method according to claim 8, wherein the water-soluble lithium compound is lithium hydroxide.
  10. 　前記水系スラリーが、前記水溶性リチウム化合物を、Ｌｉ／（Ｎｉ＋Ｍ）のモル比率で０．０１～０．１０の量で含む、請求項８又は９に記載の方法。 The method according to claim 8 or 9, wherein the aqueous slurry contains the water-soluble lithium compound in an amount of 0.01 to 0.10 in a molar ratio of Li / (Ni + M).
  11. 　前記正極活物質が、１０～４０μｍの体積基準Ｄ５０平均粒径を有する、請求項１～１０のいずれか一項に記載の方法。 The method according to any one of claims 1 to 10, wherein the positive electrode active material has a volume-based D50 average particle diameter of 10 to 40 µm.
  12. 　リチウムイオン電池用正極活物質の製造方法であって、
    　Ｎｉ１－ｙＭｙ（ＯＨ）２（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表される組成の一次粒子が多数凝集した二次粒子からなり、前記一次粒子の少なくとも一部が前記二次粒子の中心から外方に向かって放射状に並んでなる、水酸化物原料粉末又はその凝集物を用意する工程と、
    　前記水酸化物原料粉末を用いて又は前記凝集物を解砕して用いて、前記水酸化物原料粉末及び水酸化リチウムを含むスラリーを調製する工程と、
    　前記スラリーを用いて略球状の造粒粉末を作製する工程と、
    　前記造粒粉末を焼成して前記造粒粉末と前記水酸化リチウムを反応させ、それにより開気孔を備えたリチウム二次電池用正極活物質を得る工程と、
    を含んでなる方法。     A method for producing a positive electrode active material for a lithium ion battery,
    Ni 1-y M y (OH) 2 (where 0 <y ≦ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles. Preparing a hydroxide raw material powder or an aggregate thereof;
    Using the hydroxide raw material powder or pulverizing the aggregate to prepare a slurry containing the hydroxide raw material powder and lithium hydroxide;
    Producing a substantially spherical granulated powder using the slurry;
    Calcining the granulated powder to react the granulated powder with the lithium hydroxide, thereby obtaining a positive electrode active material for a lithium secondary battery having open pores;
    Comprising a method.
  13. 　Ｃｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種であって、前記水酸化物原料粉末に含まれないか又は前記水酸化物原料粉末において不足する元素を含む化合物が、前記スラリー及び／又は前記造粒粉末に添加される、請求項１～１２のいずれか一項に記載の方法。 At least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn, and Ga, which is not included in the hydroxide raw material powder or in the hydroxide raw material powder The method according to any one of claims 1 to 12, wherein a compound containing a deficient element is added to the slurry and / or the granulated powder.
  14. 　リチウムイオン電池用正極活物質の製造に用いられる活物質前駆体粉末であって、
    　Ｎｉ１－ｙＭｙ（ＯＨ）２（式中、０＜ｙ≦０．５、ＭはＣｏ、Ａｌ、Ｍｇ、Ｍｎ、Ｔｉ、Ｆｅ、Ｃｒ、Ｚｎ及びＧａからなる群から選択される少なくとも１種以上の金属元素）で表される組成の一次粒子が多数凝集した二次粒子からなり、前記一次粒子の少なくとも一部が前記二次粒子の中心から外方に向かって放射状に並んでなる、水酸化物原料粉末と、
    　前記水酸化物原料粉末及び原料微粒子の合計量に対して０～２５質量％以下の量の、前記水酸化物原料粉末と同様の組成及び前記水酸化物原料粉末よりも小さい粒径を有する原料微粒子と、
    　前記二次粒子間及び／又は前記二次粒子及び前記原料微粒子間に介在する水溶性リチウム化合物と、
    を含んでなる凝集粒子からなり、前記活物質前駆体粉末が、水中で超音波照射により解凝集された場合に、体積基準で、粒径１．０μｍ以下の粒子の割合が０～４０％であり、粒径１．０～５．０μｍの粒子の割合が６０～１００％である粒度分布を有し、かつ、焼成によるリチウム導入を経て正極活物質とされた場合に、１０～４０μｍの体積基準Ｄ５０平均粒径を有する、活物質前駆体粉末。     An active material precursor powder used for producing a positive electrode active material for a lithium ion battery,
    Ni 1-y M y (OH) 2 (where 0 <y ≦ 0.5, M is at least one selected from the group consisting of Co, Al, Mg, Mn, Ti, Fe, Cr, Zn and Ga) Consisting of secondary particles in which a large number of primary particles having a composition represented by a metal element of a species or more are aggregated, and at least a part of the primary particles are arranged radially outward from the center of the secondary particles. Hydroxide raw material powder,
    A raw material having the same composition as the hydroxide raw material powder and a particle size smaller than that of the hydroxide raw material powder, in an amount of 0 to 25% by mass or less based on the total amount of the hydroxide raw material powder and the raw material fine particles Fine particles,
    A water-soluble lithium compound interposed between the secondary particles and / or between the secondary particles and the raw material fine particles;
    When the active material precursor powder is deagglomerated in water by ultrasonic irradiation, the proportion of particles having a particle size of 1.0 μm or less is 0 to 40% on a volume basis. And having a particle size distribution in which the proportion of particles having a particle size of 1.0 to 5.0 μm is 60 to 100%, and a volume of 10 to 40 μm when made into a positive electrode active material through the introduction of lithium by firing. An active material precursor powder having a reference D50 average particle size.
  15. 　前記水溶性リチウム化合物が、水酸化リチウムである、請求項１４に記載の活物質前駆体粉末。 The active material precursor powder according to claim 14, wherein the water-soluble lithium compound is lithium hydroxide.
  16. 　前記凝集粒子が、前記水溶性リチウム化合物をＬｉ／（Ｎｉ＋Ｍ）のモル比率で０．０１～０．１０の量で含む、請求項１４又は１５に記載の活物質前駆体粉末。 The active material precursor powder according to claim 14 or 15, wherein the aggregated particles contain the water-soluble lithium compound in an amount of 0.01 to 0.10 in terms of a molar ratio of Li / (Ni + M).
  17. 　造孔剤を含まない、請求項１４～１６のいずれか一項に記載の活物質前駆体粉末。 The active material precursor powder according to any one of claims 14 to 16, which does not contain a pore-forming agent.
  18. 　焼成によるリチウム導入を経て正極活物質とされた場合に、１～３０％の空隙率及び５０％以上の開気孔比率を有する、請求項１４～１７のいずれか一項に記載の活物質前駆体粉末。 The active material precursor according to any one of claims 14 to 17, having a porosity of 1 to 30% and an open pore ratio of 50% or more when converted into a positive electrode active material through introduction of lithium by firing. Powder.
  19. 　焼成によるリチウム導入を経て正極活物質とされた場合に、０．２～３μｍの平均開気孔径を有する、請求項１４～１８のいずれか一項に記載の活物質前駆体粉末。 The active material precursor powder according to any one of claims 14 to 18, which has an average open pore size of 0.2 to 3 µm when it is converted into a positive electrode active material through introduction of lithium by calcination.
  20. 　前記正極活物質を構成する一次粒子の平均粒子径を前記平均開気孔径で除した値が０．２～３である、請求項１９に記載の活物質前駆体粉末。 The active material precursor powder according to claim 19, wherein a value obtained by dividing an average particle diameter of primary particles constituting the positive electrode active material by the average open pore diameter is 0.2 to 3.
PCT/JP2013/077742 2012-10-15 2013-10-11 Method for producing positive electrode active material for lithium secondary battery, and active material precursor powder used therein WO2014061579A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2014542104A JP5830178B2 (en) 2012-10-15 2013-10-11 Method for producing positive electrode active material for lithium secondary battery and active material precursor powder used therefor

Applications Claiming Priority (10)

Application Number Priority Date Filing Date Title
JP2012228450 2012-10-15
JP2012-228450 2012-10-15
US201261731543P 2012-11-30 2012-11-30
JP2012263072 2012-11-30
JP2012-263072 2012-11-30
US61/731,543 2012-11-30
JP2013-092628 2013-04-25
JP2013092628 2013-04-25
JP2013-149070 2013-07-18
JP2013149070 2013-07-18

Publications (1)

Publication Number Publication Date
WO2014061579A1 true WO2014061579A1 (en) 2014-04-24

Family

ID=50488145

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2013/077742 WO2014061579A1 (en) 2012-10-15 2013-10-11 Method for producing positive electrode active material for lithium secondary battery, and active material precursor powder used therein

Country Status (2)

Country Link
JP (1) JP5830178B2 (en)
WO (1) WO2014061579A1 (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016039511A1 (en) 2014-09-11 2016-03-17 주식회사 에코프로 Positive electrode active material for lithium secondary battery, and lithium secondary battery comprising same
CN106716689A (en) * 2014-09-23 2017-05-24 陶氏环球技术有限责任公司 Lithium metal oxide containing batteries having improved rate capability
JP2017533568A (en) * 2014-08-07 2017-11-09 株式会社エコプロ ビーエム Positive electrode active material for lithium secondary battery and lithium secondary battery including the same
JP2018536972A (en) * 2016-03-04 2018-12-13 エルジー・ケム・リミテッド Precursor of positive electrode active material for secondary battery and positive electrode active material produced using the same
JP2019503063A (en) * 2016-01-04 2019-01-31 ジーアールエスティー・インターナショナル・リミテッド Method for producing cathode material of lithium ion battery
WO2019147002A1 (en) * 2018-01-29 2019-08-01 삼성에스디아이 주식회사 Cathode active material for lithium secondary battery, cathode including same, and lithium secondary battery including same
CN110462897A (en) * 2017-03-31 2019-11-15 住友化学株式会社 Positive active material for lithium secondary battery, positive electrode for lithium secondary battery and lithium secondary battery
CN111656586A (en) * 2018-01-29 2020-09-11 三星Sdi株式会社 Cathode active material for lithium secondary battery, cathode including the same, and lithium secondary battery including the same
WO2022019273A1 (en) * 2020-07-21 2022-01-27 住友金属鉱山株式会社 Method for producing nickel-containing hydroxide, method for producing positive electrode active material for lithium ion secondary batteries, positive electrode active material for lithium ion secondary batteries, and lithium ion secondary battery
JP2023513027A (en) * 2020-01-29 2023-03-30 エルジー・ケム・リミテッド Positive electrode active material precursor for secondary battery, positive electrode active material, and lithium secondary battery containing the same
US11742479B2 (en) * 2014-03-28 2023-08-29 Sumitomo Metal Mining Co., Ltd. Precursor of positive electrode active material for nonaqueous electrolyte secondary batteries and production method thereof and positive electrode active material for nonaqueous electrolyte secondary batteries and production method thereof
CN117352706A (en) * 2023-12-04 2024-01-05 宁波容百新能源科技股份有限公司 Positive electrode material, preparation method thereof and lithium ion battery

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2020195463A1 (en) * 2019-03-26 2021-11-04 日本碍子株式会社 Lithium composite oxide sintered body plate

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002184403A (en) * 2000-12-14 2002-06-28 Toyota Central Res & Dev Lab Inc Manufacturing method for lithium transition metal composite oxide
JP2004079297A (en) * 2002-08-14 2004-03-11 Shin Kobe Electric Mach Co Ltd Lithium secondary battery
JP2006151707A (en) * 2004-11-25 2006-06-15 Mitsubishi Chemicals Corp Anhydride of lithium hydroxide for manufacturing lithium transition metal complex oxide and its manufacturing method, and method for manufacturing lithium transition metal complex oxide using it
WO2007037235A1 (en) * 2005-09-28 2007-04-05 Agc Seimi Chemical Co., Ltd. Process for producing lithium-containing composite oxide
JP2007242288A (en) * 2006-03-06 2007-09-20 Sumitomo Metal Mining Co Ltd Positive electrode active material for non-aqueous electrolyte secondary battery and its manufacturing method
JP2009099418A (en) * 2007-10-17 2009-05-07 Hitachi Vehicle Energy Ltd Positive electrode material for lithium secondary battery, and lithium secondary battery using the same
WO2009099158A1 (en) * 2008-02-06 2009-08-13 Agc Seimi Chemical Co., Ltd. Method for producing granular powder for positive electrode active material of lithium ion secondary battery
WO2012137534A1 (en) * 2011-04-07 2012-10-11 日本碍子株式会社 Lithium secondary battery and cathode active material thereof
WO2012169274A1 (en) * 2011-06-07 2012-12-13 住友金属鉱山株式会社 Nickel composite hydroxide and process for producing same, positive active material for nonaqueous-electrolyte secondary battery and process for producing same, and nonaqueous-electrolyte secondary battery

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002184403A (en) * 2000-12-14 2002-06-28 Toyota Central Res & Dev Lab Inc Manufacturing method for lithium transition metal composite oxide
JP2004079297A (en) * 2002-08-14 2004-03-11 Shin Kobe Electric Mach Co Ltd Lithium secondary battery
JP2006151707A (en) * 2004-11-25 2006-06-15 Mitsubishi Chemicals Corp Anhydride of lithium hydroxide for manufacturing lithium transition metal complex oxide and its manufacturing method, and method for manufacturing lithium transition metal complex oxide using it
WO2007037235A1 (en) * 2005-09-28 2007-04-05 Agc Seimi Chemical Co., Ltd. Process for producing lithium-containing composite oxide
JP2007242288A (en) * 2006-03-06 2007-09-20 Sumitomo Metal Mining Co Ltd Positive electrode active material for non-aqueous electrolyte secondary battery and its manufacturing method
JP2009099418A (en) * 2007-10-17 2009-05-07 Hitachi Vehicle Energy Ltd Positive electrode material for lithium secondary battery, and lithium secondary battery using the same
WO2009099158A1 (en) * 2008-02-06 2009-08-13 Agc Seimi Chemical Co., Ltd. Method for producing granular powder for positive electrode active material of lithium ion secondary battery
WO2012137534A1 (en) * 2011-04-07 2012-10-11 日本碍子株式会社 Lithium secondary battery and cathode active material thereof
WO2012137391A1 (en) * 2011-04-07 2012-10-11 日本碍子株式会社 Cathode active material for lithium secondary battery and lithium secondary battery
WO2012169274A1 (en) * 2011-06-07 2012-12-13 住友金属鉱山株式会社 Nickel composite hydroxide and process for producing same, positive active material for nonaqueous-electrolyte secondary battery and process for producing same, and nonaqueous-electrolyte secondary battery

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11742479B2 (en) * 2014-03-28 2023-08-29 Sumitomo Metal Mining Co., Ltd. Precursor of positive electrode active material for nonaqueous electrolyte secondary batteries and production method thereof and positive electrode active material for nonaqueous electrolyte secondary batteries and production method thereof
JP2017533568A (en) * 2014-08-07 2017-11-09 株式会社エコプロ ビーエム Positive electrode active material for lithium secondary battery and lithium secondary battery including the same
JP2020109771A (en) * 2014-09-11 2020-07-16 エコプロ ビーエム カンパニー リミテッドＥｃｏｐｒｏ Ｂｍ Ｃｏ．， Ｌｔｄ． Positive-electrode active material for lithium secondary battery and lithium secondary battery having the same
JP7121771B2 (en) 2014-09-11 2022-08-18 エコプロ ビーエム カンパニー リミテッド Positive electrode active material for lithium secondary battery and lithium secondary battery including the same
WO2016039511A1 (en) 2014-09-11 2016-03-17 주식회사 에코프로 Positive electrode active material for lithium secondary battery, and lithium secondary battery comprising same
JP2020191289A (en) * 2014-09-23 2020-11-26 ダウ グローバル テクノロジーズ エルエルシー Battery including lithium metal oxide with improved rate performance
CN106716689A (en) * 2014-09-23 2017-05-24 陶氏环球技术有限责任公司 Lithium metal oxide containing batteries having improved rate capability
JP2017535027A (en) * 2014-09-23 2017-11-24 ダウ グローバル テクノロジーズ エルエルシー Batteries containing lithium metal oxides with improved rate performance
JP7203610B2 (en) 2016-01-04 2023-01-13 ジーアールエスティー・インターナショナル・リミテッド Method for making cathode material for lithium-ion batteries
US11450848B2 (en) 2016-01-04 2022-09-20 Grst International Limited Method of preparing lithium ion battery cathode materials
JP2019503063A (en) * 2016-01-04 2019-01-31 ジーアールエスティー・インターナショナル・リミテッド Method for producing cathode material of lithium ion battery
JP2018536972A (en) * 2016-03-04 2018-12-13 エルジー・ケム・リミテッド Precursor of positive electrode active material for secondary battery and positive electrode active material produced using the same
JP2021180191A (en) * 2016-03-04 2021-11-18 エルジー・ケム・リミテッド Precursor of positive electrode active material for secondary battery, and positive electrode active material prepared using the same
JP6991530B2 (en) 2016-03-04 2022-01-12 エルジー・ケム・リミテッド A precursor of a positive electrode active material for a secondary battery and a positive electrode active material manufactured using the precursor.
US10700352B2 (en) 2016-03-04 2020-06-30 Lg Chem, Ltd. Precursor of positive electrode active material for secondary battery and positive electrode active material prepared using the same
CN110462897B (en) * 2017-03-31 2022-08-09 住友化学株式会社 Positive electrode active material for lithium secondary battery, positive electrode for lithium secondary battery, and lithium secondary battery
CN110462897A (en) * 2017-03-31 2019-11-15 住友化学株式会社 Positive active material for lithium secondary battery, positive electrode for lithium secondary battery and lithium secondary battery
WO2019147002A1 (en) * 2018-01-29 2019-08-01 삼성에스디아이 주식회사 Cathode active material for lithium secondary battery, cathode including same, and lithium secondary battery including same
CN111656586B (en) * 2018-01-29 2023-11-03 三星Sdi株式会社 Cathode active material for lithium secondary battery, cathode including the same, and lithium secondary battery including the cathode
US20200343552A1 (en) * 2018-01-29 2020-10-29 Samsung Sdi Co., Ltd. Cathode active material for lithium secondary battery, cathode including same, and lithium secondary battery including same
CN111656586A (en) * 2018-01-29 2020-09-11 三星Sdi株式会社 Cathode active material for lithium secondary battery, cathode including the same, and lithium secondary battery including the same
JP2023513027A (en) * 2020-01-29 2023-03-30 エルジー・ケム・リミテッド Positive electrode active material precursor for secondary battery, positive electrode active material, and lithium secondary battery containing the same
JPWO2022019273A1 (en) * 2020-07-21 2022-01-27
WO2022019273A1 (en) * 2020-07-21 2022-01-27 住友金属鉱山株式会社 Method for producing nickel-containing hydroxide, method for producing positive electrode active material for lithium ion secondary batteries, positive electrode active material for lithium ion secondary batteries, and lithium ion secondary battery
JP7468662B2 (en) 2020-07-21 2024-04-16 住友金属鉱山株式会社 Method for producing nickel-containing hydroxide, method for producing positive electrode active material for lithium ion secondary battery, positive electrode active material for lithium ion secondary battery, lithium ion secondary battery
CN117352706A (en) * 2023-12-04 2024-01-05 宁波容百新能源科技股份有限公司 Positive electrode material, preparation method thereof and lithium ion battery

Also Published As

Publication number Publication date
JPWO2014061579A1 (en) 2016-09-05
JP5830178B2 (en) 2015-12-09

Similar Documents

Publication Publication Date Title
JP6196175B2 (en) Method for producing positive electrode active material for lithium secondary battery and active material precursor powder used therefor
JP5830178B2 (en) Method for producing positive electrode active material for lithium secondary battery and active material precursor powder used therefor
JP6230540B2 (en) Positive electrode active material for lithium secondary battery and positive electrode using the same
JP5830179B2 (en) Method for producing positive electrode active material for lithium secondary battery and active material precursor powder used therefor
CN108352527B (en) Positive electrode active material for nonaqueous electrolyte secondary battery, method for producing same, and nonaqueous electrolyte secondary battery
JP5971109B2 (en) Nickel composite hydroxide and production method thereof, positive electrode active material for non-aqueous electrolyte secondary battery, production method thereof, and non-aqueous electrolyte secondary battery
JP5741932B2 (en) Transition metal composite hydroxide as a precursor of a positive electrode active material for a non-aqueous electrolyte secondary battery, a method for producing the same, and a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery
JP4894969B1 (en) Nickel-manganese composite hydroxide particles and production method thereof, positive electrode active material for non-aqueous electrolyte secondary battery and production method thereof, and non-aqueous electrolyte secondary battery
JP5843753B2 (en) Positive electrode active material for lithium ion battery, positive electrode for lithium ion battery, and lithium ion battery
JP7188081B2 (en) TRANSITION METAL CONTAINING COMPOSITE HYDROXIDE AND MANUFACTURING METHOD THEREOF, POSITIVE ACTIVE MATERIAL FOR NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY AND MANUFACTURING METHOD THEREOF, AND NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY
WO2012131881A1 (en) Nickel-manganese composite hydroxide particles, method for producing same, positive electrode active material for nonaqueous electrolyte secondary batteries, method for producing positive electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery
KR20120099118A (en) Positive electrode active material for lithium-ion battery, positive electrode for lithium-ion battery, and lithium-ion battery
JP2012252844A5 (en)
JP7260249B2 (en) TRANSITION METAL CONTAINING COMPOSITE HYDROXIDE PARTICLES AND MANUFACTURING METHOD THEREFOR, POSITIVE ACTIVE MATERIAL FOR NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY AND MANUFACTURING METHOD THEREOF, AND NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY
JP5811383B2 (en) Positive electrode active material for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery using the positive electrode active material
JP2020177860A (en) Composite hydroxide containing nickel, manganese and cobalt and production method thereof, composite oxide containing lithium, nickel, manganese and cobalt and production method thereof, positive electrode active material for lithium ion secondary battery and production method thereof, and lithium ion secondary battery
JP2014049410A (en) Manufacturing method of cathode active material for lithium-ion battery
JP2014067694A (en) Method for producing positive electrode active material for lithium secondary battery or precursor thereof
JP7159639B2 (en) Method for producing particles of transition metal composite hydroxide, and method for producing positive electrode active material for lithium ion secondary battery
WO2003083969A1 (en) Positive electrode material for lithium secondary cell and secondary cell using the same, and method for producing positive electrode material for lithium secondary cell
JP7183815B2 (en) Nickel-manganese-cobalt-containing composite hydroxide and manufacturing method thereof, positive electrode active material for lithium ion secondary battery and manufacturing method thereof, and lithium ion secondary battery
JP7183813B2 (en) Nickel-manganese-cobalt-containing composite hydroxide and manufacturing method thereof, positive electrode active material for lithium ion secondary battery and manufacturing method thereof, and lithium ion secondary battery
JP2014049407A (en) Method of manufacturing cathode active material for lithium secondary battery
JP7110647B2 (en) Lithium-nickel-containing composite oxide, method for producing the same, lithium-ion secondary battery, and evaluation method for lithium-nickel-containing composite oxide
JP2005050582A (en) Positive pole for lithium secondary battery and lithium secondary battery using it

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: 13847522

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2014542104

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: 13847522

Country of ref document: EP

Kind code of ref document: A1